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Sample records for aerobot thermo-mechanical subsystem

  1. Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development

    NASA Technical Reports Server (NTRS)

    Pauken, Michael T.; Hall, Jeffery L.

    2006-01-01

    This paper presents experimental results on a set of 4 thermo-mechanical research tasks aimed at Titan and Venus aerobots: 1. A cryogenic balloon materials development program culminating in the fabrication and testing of a 4.6 m long blimp prototype at 93K. 2. A combined computational and experimental thermal analysis of the effect of radioisotope power system (RPS) waste heat on the behavior of a helium filled blimp hull. 3. Aerial deployment and inflation testing using a blimp 4. A proof of concept experiment with an aerobot-mounted steerable high gain antenna These tasks were supported with JPL internal R&D funds and executed by JPL engineers with substantial industry collaboration for Task #1, the cryogenic balloon materials

  2. Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development

    NASA Technical Reports Server (NTRS)

    Hall, Jeffrey L.; Jones, J. A.; Kerzhanovich, V. V.; Lachenmeier, T.; Mahr, P.; Pauken, M.; Plett, G. A.; Smith, L.; VanLuvender, M. L.; Yavrouian, A. H.

    2006-01-01

    This paper describes experimental results from a development program focused in maturing Titan aerobot technology in the areas of mechanical and thermal subsystems. Results from four key activities are described: first, a cryogenic balloon materials development program involving coupon and cylinder tests and culminating in the fabrication and testing of an inflated 4.6 m long prototype blimp at 93 K; second, a combined lab experiment and numerical simulation effort to assess potential problems resulting from radioisotope thermal generator waste heat generation near an inflated blimp; third, an aerial deployment and inflation development program consisting of laboratory and helicopter drop tests on a near full scale (11 m long) prototype blimp; and fourth, a proof of concept experiment demonstrating the viability of using a mechanically steerable high gain antenna on a floating blimp to perform direct to Earth telecommunications from Titan. The paper provides details on all of these successful activities and discusses their impact on the overall effort to produce mature systems technology for future Titan aerobot missions.

  3. Venus Aerobot Multisonde Mission

    NASA Technical Reports Server (NTRS)

    Cutts, James A.; Kerzhanovich, Viktor; Balaram, J. Bob; Campbell, Bruce; Gershaman, Robert; Greeley, Ronald; Hall, Jeffery L.; Cameron, Jonathan; Klaasen, Kenneth; Hansen, David M.

    1999-01-01

    Robotic exploration of Venus presents many challenges because of the thick atmosphere and the high surface temperatures. The Venus Aerobot Multisonde mission concept addresses these challenges by using a robotic balloon or aerobot to deploy a number of short lifetime probes or sondes to acquire images of the surface. A Venus aerobot is not only a good platform for precision deployment of sondes but is very effective at recovering high rate data. This paper describes the Venus Aerobot Multisonde concept and discusses a proposal to NASA's Discovery program using the concept for a Venus Exploration of Volcanoes and Atmosphere (VEVA). The status of the balloon deployment and inflation, balloon envelope, communications, thermal control and sonde deployment technologies are also reviewed.

  4. Aerobot Autonomy Architecture

    NASA Technical Reports Server (NTRS)

    Elfes, Alberto; Hall, Jeffery L.; Kulczycki, Eric A.; Cameron, Jonathan M.; Morfopoulos, Arin C.; Clouse, Daniel S.; Montgomery, James F.; Ansar, Adnan I.; Machuzak, Richard J.

    2009-01-01

    An architecture for autonomous operation of an aerobot (i.e., a robotic blimp) to be used in scientific exploration of planets and moons in the Solar system with an atmosphere (such as Titan and Venus) is undergoing development. This architecture is also applicable to autonomous airships that could be flown in the terrestrial atmosphere for scientific exploration, military reconnaissance and surveillance, and as radio-communication relay stations in disaster areas. The architecture was conceived to satisfy requirements to perform the following functions: a) Vehicle safing, that is, ensuring the integrity of the aerobot during its entire mission, including during extended communication blackouts. b) Accurate and robust autonomous flight control during operation in diverse modes, including launch, deployment of scientific instruments, long traverses, hovering or station-keeping, and maneuvers for touch-and-go surface sampling. c) Mapping and self-localization in the absence of a global positioning system. d) Advanced recognition of hazards and targets in conjunction with tracking of, and visual servoing toward, targets, all to enable the aerobot to detect and avoid atmospheric and topographic hazards and to identify, home in on, and hover over predefined terrain features or other targets of scientific interest. The architecture is an integrated combination of systems for accurate and robust vehicle and flight trajectory control; estimation of the state of the aerobot; perception-based detection and avoidance of hazards; monitoring of the integrity and functionality ("health") of the aerobot; reflexive safing actions; multi-modal localization and mapping; autonomous planning and execution of scientific observations; and long-range planning and monitoring of the mission of the aerobot. The prototype JPL aerobot (see figure) has been tested extensively in various areas in the California Mojave desert.

  5. Mars Aerobot Validation Program

    NASA Technical Reports Server (NTRS)

    Kerzhanovich, V. V.; Cutts, J.; Bachelder, A.; Cameron, J.; Patzold, J.; Quadrelli, M.; Yavrouian, A.; Cantrell, J.; Lachenmeier, T.; Smith, M.

    1999-01-01

    The Mars Balloon Validation Program (MABVAP) was initiated in August 1997 to develop and validate key technologies needed for aerobot missions on Mars. The major elements of the program are the development of balloons for flight on Mars, robust techniques for deployment and inflation and modeling and simulation of balloon flight paths. selection, development and tests of available balloon materials, design and fabrication of balloons (both superpressure and solar- heated), design and fabrication of deployment and inflation systems for aerial deployment, design and fabrication of avionics to control deployment/inflation process and to get telemetry and video data. Modeling of main processes during deployment and actual flight is also a part of MABVAP. In order to validate deployment and inflation, MABVAP applies experience from previous Mars balloon development or study activities the Russian-French Mars Aerostat Project (1988-1995), Mars Aerial Platform Study (1994) and Mars Aerobot/Balloon Study (1996). The program includes laboratory, wind tunnel, vacuum chamber tests of the system components and a number of tropospheric and stratospheric flight tests of deployment and inflation of lightfilm balloons in a simulated Martian environment.

  6. Planning Flight Paths of Autonomous Aerobots

    NASA Technical Reports Server (NTRS)

    Kulczycki, Eric; Elfes, Alberto; Sharma, Shivanjli

    2009-01-01

    Algorithms for planning flight paths of autonomous aerobots (robotic blimps) to be deployed in scientific exploration of remote planets are undergoing development. These algorithms are also adaptable to terrestrial applications involving robotic submarines as well as aerobots and other autonomous aircraft used to acquire scientific data or to perform surveying or monitoring functions.

  7. Columnar Jointing Thermo-Mechanics

    NASA Astrophysics Data System (ADS)

    Iddon, Fiona; Hornby, Adrian; Kendrick, Jackie; Wadsworth, Fabian; von Aulock, Felix; Lavallée, Yan

    2014-05-01

    Thermo-mechanical effects, common to a wide range of geological phenomena, are integral to the formation of columnar joints during cooling and crystallisation of lava flows. The process, and resultant geometry, relies on a complex inter-play between heat distribution, contraction and tensile strength, yet the kinetics of their formation remains elusive. Results are presented from a combination of field survey, thermo-analytical characterisation and mechanical investigation to constrain conditions favourable for columnar jointing. Columnar joints from Seljavallir, Iceland, produce quadratic to heptagonal cross sectional patterns with column widths ranging from 20 to 70 cm in size. The fracture surfaces are characterised by striae of which spacing (between 1 to 6 cm) appear to share a positive linear relationship to the joint spacing. The striae exhibit both a smooth and rough portion, interpreted to express a change in deformation regime from fully brittle, mode-I fracture propagation to an increasingly ductile response of the lava with tensile fracture dissipation as the fracture event wanes. The contraction of the basalts has been investigated via the expansion coefficient determined in a dilatometer (at 3mN of normal stress and a rate of 2 °C/min). The expansion coefficient has been constrained to 10-5/°C and the onset of melting (and completion of natural crystallisation) at 1150°C. Experiments are currently being conducted to assess the effect of cooling rate and normal stress on the properties of the Seljavallir basalts. The mechanical properties of the rock in tension have been tested at room temperature in a uniaxial press (high-temperature tests are also scheduled). During true-tension pull test at a strain rate of 10-4 s-1, elastic deformation agrees to a Young's modulus of 6.3 GPa. Tensile failure initiated after 0.35% strain with the generation of a large crack at a peak stress of 2.2 MPa. The fracture induced a stress drop and upon stress build-up to

  8. Aerobots as a Ubiquitous Part of Society

    NASA Technical Reports Server (NTRS)

    Young, Larry A.

    2006-01-01

    Small autonomous aerial robots (aerobots) have the potential to make significant positive contributions to modern society. Aerobots of various vehicle-types - CTOL, STOL, VTOL, and even possibly LTA - will be a part of a new paradigm for the distribution of goods and services. Aerobots as a class of vehicles may test the boundaries of aircraft design. New system analysis and design tools will be required in order to account for the new technologies and design parameters/constraints for such vehicles. The analysis tools also provide new approaches to defining/assessing technology goals and objectives and the technology portfolio necessary to accomplish those goals and objectives. Using the aerobot concept as an illustrative test case, key attributes of these analysis tools are discussed.

  9. On-Board Perception System For Planetary Aerobot Balloon Navigation

    NASA Technical Reports Server (NTRS)

    Balaram, J.; Scheid, Robert E.; T. Salomon, Phil

    1996-01-01

    NASA's Jet Propulsion Laboratory is implementing the Planetary Aerobot Testbed to develop the technology needed to operate a robotic balloon aero-vehicle (Aerobot). This earth-based system would be the precursor for aerobots designed to explore Venus, Mars, Titan and other gaseous planetary bodies. The on-board perception system allows the aerobot to localize itself and navigate on a planet using information derived from a variety of celestial, inertial, ground-imaging, ranging, and radiometric sensors.

  10. Technology Validation Program for Mars Aerobot Micromission

    NASA Technical Reports Server (NTRS)

    Cutts, J.; Kerzhanovich, V.; Bachelder, A.; Patzold, J.; Cameron, J.; Hall, J.; Jones, J.; Weiss, J.; Yavrouian, A.

    1999-01-01

    The Mars Aerobot Validation Program (MABVAP) was initiated in August 1997 to develop and validate key technologies needed for aerobot missions on Mars. The major elements of the program are the development of balloons for flight on Mars, robust techniques for deployment and inflation and modeling and simulation of balloon flight paths, selection, development and tests of available balloon materials, design and fabrication of balloons (both superpressure and solar-heated), design and fabrication of deployment and inflation systems for aerial deployment, design and fabrication of avionics to control deployment/inflation process and to get telemetry and video data. The program includes laboratory, wind tunnel, vacuum chamber tests of the system components and a number of tropospheric and stratospheric flight tests of deployment and inflation of light-film balloons in a simulated Martian environment Key issues in the design include: the use of proven materials or their combinations; the availability of adequate balloon fabrication technologies and processes; evacuation of gas from the balloon prior to packaging and the design of a balloon container capable of storing the balloon over a wide range of ambient pressures. Tests that have been made at JPL and at the Vertical Wind Tunnel at NASA Langley Research Center clarified many of the first order issues discussed above and lead to the baseline configuration with inflation from the bottom without a reefing mechanism.

  11. Thermo-mechanical characterization of silicone foams

    SciTech Connect

    Rangaswamy, Partha; Smith, Nickolaus A.; Cady, Carl M.; Lewis, Matthew W.

    2015-10-01

    Cellular solids such as elastomeric foams are used in many structural applications to absorb and dissipate energy, due to their light weight (low density) and high energy absorption capability. In this paper we will discuss foams derived from S5370, a silicone foam formulation developed by Dow Corning. In the application presented, the foam is consolidated into a cushion component of constant thickness but variable density. A mechanical material model developed by Lewis (2013), predicts material response, in part, as a function of relative density. To determine the required parameters for this model we have obtained the mechanical response in compression for ambient, cold and hot temperatures. The variable density cushion provided samples sufficient samples so that the effect of sample initial density on the mechanical response could be studied. The mechanical response data showed extreme sensitivity to relative density. We also observed at strains corresponding to 1 MPa a linear relationship between strain and initial density for all temperatures. Samples taken from parts with a history of thermal cycling demonstrated a stiffening response that was a function of temperature, with the trend of more stiffness as temperature increased above ambient. This observation is in agreement with the entropic effects on the thermo-mechanical behavior of silicone polymers. In this study, we present the experimental methods necessary for the development of a material model, the testing protocol, analysis of test data, and a discussion of load (stress) and gap (strain) as a function of sample initial densities and temperatures

  12. Robust and Opportunistic Autonomous Science for a Potential Titan Aerobot

    NASA Technical Reports Server (NTRS)

    Gaines, Daniel M.; Estlin, Tara; Schaffer, Steve; Castano, Rebecca; Elfes, Alberto

    2010-01-01

    We are developing onboard planning and execution technologies to provide robust and opportunistic mission operations for a potential Titan aerobot. Aerobot have the potential for collecting a vast amount of high priority science data. However, to be effective, an aerobot must address several challenges including communication constraints, extended periods without contact with Earth, uncertain and changing environmental conditions, maneuverability constraints and potentially short-lived science opportunities. We are developing the AerOASIS system to develop and test technology to support autonomous science operations for a potential Titan Aerobot. The planning and execution component of AerOASIS is able to generate mission operations plans that achieve science and engineering objectives while respecting mission and resource constraints as well as adapting the plan to respond to new science opportunities. Our technology leverages prior work on the OASIS system for autonomous rover exploration. In this paper we describe how the OASIS planning component was adapted to address the unique challenges of a Titan Aerobot and we describe a field demonstration of the system with the JPL prototype aerobot.

  13. Near-field NanoThermoMechanical memory

    SciTech Connect

    Elzouka, Mahmoud; Ndao, Sidy

    2014-12-15

    In this letter, we introduce the concept of NanoThermoMechanical Memory. Unlike electronic memory, a NanoThermoMechanical memory device uses heat instead of electricity to record, store, and recover data. Memory function is achieved through the coupling of near-field thermal radiation and thermal expansion resulting in negative differential thermal resistance and thermal latching. Here, we demonstrate theoretically via numerical modeling the concept of near-field thermal radiation enabled negative differential thermal resistance that achieves bistable states. Design and implementation of a practical silicon based NanoThermoMechanical memory device are proposed along with a study of its dynamic response under write/read cycles. With more than 50% of the world's energy losses being in the form of heat along with the ever increasing need to develop computer technologies which can operate in harsh environments (e.g., very high temperatures), NanoThermoMechanical memory and logic devices may hold the answer.

  14. Near-field NanoThermoMechanical memory

    NASA Astrophysics Data System (ADS)

    Elzouka, Mahmoud; Ndao, Sidy

    2014-12-01

    In this letter, we introduce the concept of NanoThermoMechanical Memory. Unlike electronic memory, a NanoThermoMechanical memory device uses heat instead of electricity to record, store, and recover data. Memory function is achieved through the coupling of near-field thermal radiation and thermal expansion resulting in negative differential thermal resistance and thermal latching. Here, we demonstrate theoretically via numerical modeling the concept of near-field thermal radiation enabled negative differential thermal resistance that achieves bistable states. Design and implementation of a practical silicon based NanoThermoMechanical memory device are proposed along with a study of its dynamic response under write/read cycles. With more than 50% of the world's energy losses being in the form of heat along with the ever increasing need to develop computer technologies which can operate in harsh environments (e.g., very high temperatures), NanoThermoMechanical memory and logic devices may hold the answer.

  15. Venus Aerobot Surface Science Imaging System (VASSIS)

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1999-01-01

    The VASSIS task was to design and develop an imaging system and container for operation above the surface of Venus in preparation for a Discovery-class mission involving a Venus aerobot balloon. The technical goals of the effort were to: a) evaluate the possible nadir-viewed surface image quality as a function of wavelength and altitude in the Venus lower atmosphere, b) design a pressure vessel to contain the imager and supporting electronics that will meet the environmental requirements of the VASSIS mission, c) design and build a prototype imaging system including an Active-Pixel Sensor camera head and VASSIS-like optics that will meet the science requirements. The VASSIS science team developed a set of science requirements for the imaging system upon which the development work of this task was based.

  16. Aerobot measurements successfully obtained during Solo Spirit Balloon Mission

    NASA Astrophysics Data System (ADS)

    Avidson, Raymond E.; Bowman, Judd D.; Guinness, Edward A.; Johnson, Sarah S.; Slavney, S. H.; Stein, Thomas C.; Bachelder, Aaron D.; Cameron, Jonathan M.; Cutts, James A.; Ivlev, Robert V.; Kahn, Ralph A.

    Robotic balloons, also known as aerobots, have become candidates for collecting atmospheric data and detailed surface observations of Venus, Mars, and Titan. A mission to Venus over a decade ago used two of them. Their inclusion last year in attempts by a balloonist to circumnavigate the Earth aptly demonstrated their utility for remote sensing and in situ observations of planetary atmospheres.To simulate aspects of an aerobot mission, a small payload to measure local atmospheric conditions and balloon position and velocity was included on Solo Spirit “Round the World” flights during January and August of last year. These missions, flown in Roziere balloons, were attempts by Steve Fossett to become the first person to circumnavigate the globe in a balloon without stopping. Neither attempt was successful, but the aerobot came through with flying colors.

  17. An aerobot for global in situ exploration of Titan

    NASA Technical Reports Server (NTRS)

    Hall, Jeffery L.; Kerzhanovich, V. V.; Yavrouian, A. H.; Jones, J. A.; White, C. V.; Dudik, B. A.; Plett, G. A.; Menella, J.; Elfes, A.

    2004-01-01

    This paper describes the design and component testing of an aerobot that would be capable of global in situ exploration of Saturn's moon, Titan, over a 6 to 12 month mission lifetime. The proposed aerobot is a propeller-driven, buoyant vehicle that resembles terrestrial airships. However, the extremely cold Titan environment requires the use of cryogenic materials of construction and careful thermal design for protection of temperature-sensitive payload elements. Multiple candidate balloon materials have been identified based on extensive laboratory testing at 77 K. The most promising materials to date are laminates comprised of polyester fabrics and/or films with areal densities in the range of 40-100 g/m2. The aerobot hull is a streamlined ellipsoid 14 meters in length with a maximum diameter of 3 meters. The enclosed volume of 60 m3 is sufficient to float a mass of 234 kg at a maximum altitude of 8 km at Titan. Forward and aft ballonets are located inside the hull to enable the aerobot to descend to the surface while preserving a fully inflated streamlined shape. Altitude changes are effected primarily through thrust vectoring of the twin main propellers, with pressure modulated buoyancy change via the ballonets available as a slower backup option. A total of 100 W of electrical power is provided to the vehicle by a radioisotope power supply. Up to half of this power is available to the propulsion system to generate a top flight speed in the range of 1-2 m/s. This speed is expected to be greater than the near surface winds at Titan, enabling the aerobot to fly to and hover over targets of interest. A preliminary science payload has been devised for the aerobot to give it the capability for aerial imaging of the surface, atmospheric observations and sampling, and surface sample acquisition and analysis. Targeting, hovering, surface sample acquisition and vehicle health monitoring and automatic safing actions will all require significant on-board autonomy due to

  18. An aerobot for global in situ exploration of Titan

    NASA Astrophysics Data System (ADS)

    Hall, J. L.; Kerzhanovich, V. V.; Yavrouian, A. H.; Jones, J. A.; White, C. V.; Dudik, B. A.; Plett, G. A.; Mennella, J.; Elfes, A.

    This paper describes the design and component testing of an aerobot that would be capable of global in situ exploration of Saturn's moon, Titan, over a 6-12 month mission lifetime. The proposed aerobot is a propeller-driven, buoyant vehicle that resembles terrestrial airships. However, the extremely cold Titan environment requires the use of cryogenic materials of construction and careful thermal design for protection of temperature-sensitive payload elements. Multiple candidate balloon materials have been identified based on extensive laboratory testing at 77 K. The most promising materials to date are laminates comprised of polyester fabrics and/or films with areal densities in the range of 40-100 g/m 2. The aerobot hull is a streamlined ellipsoid 14 m in length with a maximum diameter of 3 m. The enclosed volume of 60 m 3 is sufficient to float a mass of 234 kg at a maximum altitude of 8 km at Titan. Forward and aft ballonets are located inside the hull to enable the aerobot to descend to the surface while preserving a fully inflated streamlined shape. Altitude changes are effected primarily through thrust vectoring of the twin main propellers, with pressure modulated buoyancy change via the ballonets available as a slower backup option. A total of 100 W of electrical power is provided to the vehicle by a radioisotope power supply. Up to half of this power is available to the propulsion system to generate a top flight speed in the range of 1-2 m/s. This speed is expected to be greater than the near surface winds at Titan, enabling the aerobot to fly to and hover over targets of interest. A preliminary science payload has been devised for the aerobot to give it the capability for aerial imaging of the surface, atmospheric observations and sampling, and surface sample acquisition and analysis. Targeting, hovering, surface sample acquisition and vehicle health monitoring and automatic safing actions will all require significant on-board autonomy due to the over 2 h

  19. An Aerobot for Global In Situ Exploration of Titan

    NASA Astrophysics Data System (ADS)

    Hall, J.; Kerzhanovich, V.; Yavrouian, A.; Jones, J.; White, C.; Dudik, B.; Elfes, A.

    This paper describes the design and component testing of an aerobot that will be capable of global in situ exploration of Saturn's moon, Titan, over a 6 to 12 month mission lifetime. The proposed aerobot is a propeller-driven, buoyant vehicle that resembles terrestrial airships. However, the extremely cold Titan environment requires the use of cryogenic materials of construction and careful thermal design for protection of temperature-sensitive payload elements. Multiple candidate balloon materials have been identified based on extensive laboratory testing at 77 K. The most promising materials to date are laminates comprised of polyester fabrics and/or films with areal densities in the range of 40-100 g/m^2. The aerobot hull is a streamlined ellipsoid 12 meters in length with a maximum diameter of 3 meters. The enclosed volume of 56 m^3 is sufficient to float a mass of 200 kg at a maximum altitude of 8 km at Titan. Forward and aft ballonets are located inside the hull to enable the aerobot to descend to the surface while preserving a fully inflated streamlined shape. Altitude changes are effected primarily through thrust vectoring of the twin main propellers, with pressure modulated buoyancy change via the ballonets available as a slower backup option. A total of 100 W of electrical power is provided to the vehicle by a radioisotope thermal generator. Up to half of this power is available to the propulsion system to generate a top flight speed in the range of 1-2 m/s. This speed is expected to be greater than the near surface winds at Titan, enabling the aerobot to fly to and hover over targets of interest. A preliminary science payload has been devised for the aerobot to give it the capability for aerial imaging of the surface, atmospheric observations and sampling, and surface sample acquisition and analysis. Targeting, hovering, surface sample acquisition and vehicle health monitoring and reflexive safing actions will all require significant on-board autonomy

  20. Thermo-Mechanical Modeling and Analysis for Turbopump Assemblies

    NASA Technical Reports Server (NTRS)

    Platt, Mike; Marsh, Matt

    2003-01-01

    Life, reliability, and cost are strongly impacted by steady and transient thermo-mechanical effect. Design cycle can suffer big setbacks when working a transient stress/deflection issue. Balance between objectives and constrains is always difficult. Requires assembly-level analysis early in the design cycle.

  1. Thermo-Mechanical Processing Parameters for the INCONEL ALLOY 740

    SciTech Connect

    Ludtka, G.M.; Smith, G.

    2007-11-19

    In 2000, a Cooperative Research and Development Agreement (CRADA) was undertaken between the Oak Ridge National Laboratory (ORNL) and the Special Metals Corporation (SMC) to determine the mechanical property response of the IN740 alloy to help establish thermo-mechanical processing parameters for the use of this alloy in supercritical and ultra-critical boiler tubes with the potential for other end uses. SMC had developed an alloy, commercially known as INCONEL alloy 740, which exhibited various beneficial physical, mechanical, and chemical properties. As part of SMC's on-going efforts to optimize this alloy for targeted boiler applications there was a need to develop an understanding of the thermo-mechanical response of the material, characterize the resulting microstructure from this processing, and possibly, utilize models to develop the appropriate processing scheme for this product.

  2. Universal mechanism of thermo-mechanical deformation in metallic glasses

    DOE PAGES

    Dmowski, W.; Tong, Y.; Iwashita, T.; ...

    2015-02-11

    Here we investigated the atomistic structure of metallic glasses subjected to thermo-mechanical creep deformation using high energy x-ray diffraction and molecular dynamics simulation. The experiments were performed in-situ, at high temperatures as a time dependent deformation in the elastic regime, and ex-situ on samples quenched under stress. We show that all the anisotropic structure functions of the samples undergone thermo-mechanical creep can be scaled into a single curve, regardless of the magnitude of anelastic strain, stress level and the sign of the stress, demonstrating universal behavior and pointing to unique atomistic unit of anelastic deformation. The structural changes due tomore » creep are strongly localized within the second nearest neighbors, involving only a small group of atoms.« less

  3. Universal mechanism of thermo-mechanical deformation in metallic glasses

    SciTech Connect

    Dmowski, W.; Tong, Y.; Iwashita, T.; Egami, Takeshi; Yokoyama, Y.

    2015-02-11

    Here we investigated the atomistic structure of metallic glasses subjected to thermo-mechanical creep deformation using high energy x-ray diffraction and molecular dynamics simulation. The experiments were performed in-situ, at high temperatures as a time dependent deformation in the elastic regime, and ex-situ on samples quenched under stress. We show that all the anisotropic structure functions of the samples undergone thermo-mechanical creep can be scaled into a single curve, regardless of the magnitude of anelastic strain, stress level and the sign of the stress, demonstrating universal behavior and pointing to unique atomistic unit of anelastic deformation. The structural changes due to creep are strongly localized within the second nearest neighbors, involving only a small group of atoms.

  4. Geomorphological-thermo-mechanical modeling: Application to orogenic wedge dynamics

    NASA Astrophysics Data System (ADS)

    Ueda, K.; Willett, S. D.; Gerya, T.; Ruh, J.

    2015-09-01

    Coupled geomorphological-thermo-mechanical modeling is presented in a new implementation that combines two established thermo-mechanical and landscape evolution models. A finite-difference marker-in-cell technique is used to solve for the thermo-mechanical problem including complex visco-plastic rheologies in high resolution. Each timestep is synchronously solved with a fluvial landscape evolution model that includes numerical solution of fluvial incision and analytical hillslope processes for both diffusive and slope-limited processes on an adaptive grid. The implementation is successful in modeling large deformation at different scales. We demonstrate high degrees of coupling through processes such as exhumation of rocks with different erodibilities. Sensitivity of the coupled system evolution to surface parameters, and mechanical parameters, is explored for the established case of development of compressive wedges. The evolution of wedge models proves to be primarily sensitive to erodibility and the degree of river network integration. Relief follows deformation in propagating forward with wedge growth. We apply the method to a large-scale model of continental collision, in which a close relationship between deep tectonics, fluvial network evolution, and uplift and erosion can be demonstrated.

  5. Trajectory Generation and Path Planning for Autonomous Aerobots

    NASA Technical Reports Server (NTRS)

    Sharma, Shivanjli; Kulczycki, Eric A.; Elfes, Alberto

    2007-01-01

    This paper presents global path planning algorithms for the Titan aerobot based on user defined waypoints in 2D and 3D space. The algorithms were implemented using information obtained through a planner user interface. The trajectory planning algorithms were designed to accurately represent the aerobot's characteristics, such as minimum turning radius. Additionally, trajectory planning techniques were implemented to allow for surveying of a planar area based solely on camera fields of view, airship altitude, and the location of the planar area's perimeter. The developed paths allow for planar navigation and three-dimensional path planning. These calculated trajectories are optimized to produce the shortest possible path while still remaining within realistic bounds of airship dynamics.

  6. Thermo-mechanical coupling strategies in elastic-plastic problems

    NASA Astrophysics Data System (ADS)

    Vaz, M.; Lange, M. R.

    2017-03-01

    Modeling strategies aimed at thermo-mechanical coupled problems has been developed for a wide range of engineering applications. Staggered-type coupling procedures have been largely used in materials processing operations, especially in commercial codes, owing to their simplicity and flexibility. The present work shows that, in thermo-plastic problems, the classical implementation of the most common coupling procedure may present accuracy issues and time-stepping dependency. Numerical experiments indicate that an iterative coupling scheme constitutes a viable and simple approach to this class of problems.

  7. Coupled Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    NASA Technical Reports Server (NTRS)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2000-01-01

    A procedure that models coupled thermo-mechanical deformations of viscoelastic rubber cylinders by employing the ABAQUS finite element code is described. Computational simulations of hysteretic heating are presented for several tall and short rubber cylinders both with and without a steel disk at their centers. The cylinders are compressed axially and are then cyclically loaded about the compressed state. The non-uniform hysteretic heating of the rubber cylinders containing a steel disk is presented. The analyses performed suggest that the coupling procedure should be considered for further development as a design tool for rubber degradation studies.

  8. Continuous damage parameter calculation under thermo-mechanical random loading.

    PubMed

    Nagode, Marko

    2014-01-01

    The paper presents a method on how the mean stress effect on fatigue damage can be taken into account under an arbitrary low cycle thermo-mechanical loading. From known stress, elastoplastic strain and temperature histories the cycle amplitudes and cycle mean values are extracted and the damage parameter is computed. In contrast to the existing methods the proposed method enables continuous damage parameter computation without the need of waiting for the cycles to close. The limitations of the standardized damage parameters are thus surpassed. The damage parameters derived initially for closed and isothermal cycles assuming that the elastoplastic stress-strain response follows the Masing and memory rules can now be used to take the mean stress effect into account under an arbitrary low cycle thermo-mechanical loading. The method includes:•stress and elastoplastic strain history transformation into the corresponding amplitude and mean values;•stress and elastoplastic strain amplitude and mean value transformation into the damage parameter amplitude history;•damage parameter amplitude history transformation into the damage parameter history.

  9. Continuous damage parameter calculation under thermo-mechanical random loading

    PubMed Central

    Nagode, Marko

    2014-01-01

    The paper presents a method on how the mean stress effect on fatigue damage can be taken into account under an arbitrary low cycle thermo-mechanical loading. From known stress, elastoplastic strain and temperature histories the cycle amplitudes and cycle mean values are extracted and the damage parameter is computed. In contrast to the existing methods the proposed method enables continuous damage parameter computation without the need of waiting for the cycles to close. The limitations of the standardized damage parameters are thus surpassed. The damage parameters derived initially for closed and isothermal cycles assuming that the elastoplastic stress–strain response follows the Masing and memory rules can now be used to take the mean stress effect into account under an arbitrary low cycle thermo-mechanical loading. The method includes:•stress and elastoplastic strain history transformation into the corresponding amplitude and mean values;•stress and elastoplastic strain amplitude and mean value transformation into the damage parameter amplitude history;•damage parameter amplitude history transformation into the damage parameter history. PMID:26150939

  10. Thermo-mechanical properties of polyester mortar using recycled PET

    SciTech Connect

    Rebeiz, K.S.; Craft, A.P.

    1997-07-01

    The thermo-mechanical properties of polyester mortar (PM) using unsaturated polyester resins based on recycled PET are investigated in this paper (the recycled PET waste is mainly obtained from used plastic beverage bottles). The use of recycled PET in PM formulation is important because it helps produce good quality PM at a relatively low cost, save energy and alleviate an environmental problem posed by plastic wastes. PM construction applications include the repair of dams, piers, runways, bridges and other structures. Test results show that the effective use of PM overlays on portland cement concrete slabs is best achieved by utilizing flexible resins with low modulus and high elongation capacity at failure. The use of flexible resins in PM production is especially important in situations involving large thermal movements.

  11. Thermo-mechanical process for treatment of welds

    SciTech Connect

    Malik, R K

    1980-03-01

    Benefits from thermo-mechanical processing (TMP) of austenitic stainless steel weldments, analogous to hot isostatic pressing (HIP) of castings, most likely result from compressive plastic deformation, enhanced diffusion, and/or increased dislocation density. TMP improves ultrasonic inspectability of austenitic stainless steel welds owing to: conversion of cast dendrites into equiaxed austenitic grains, reduction in size and number of stringers and inclusions, and reduction of delta ferrite content. TMP induces structural homogenization and healing of void-type defects and thus contributes to an increase in elongation, impact strength, and fracture toughness as well as a significant reduction in data scatter for these properties. An optimum temperature for TMP or HIP of welds is one which causes negligible grain growth and an acceptable reduction in yield strength, and permits healing of porosity.

  12. Thermo-mechanical Deformation in Magneto-micropolar Elastic Medium

    NASA Astrophysics Data System (ADS)

    Kumar, Rajneesh; Rupender

    2009-04-01

    The present investigation is concerned with a two-dimensional problem in electromagnetic micropolar elasticity for a half-space whose surface is subjected to distributed (concentrated or continuous) thermo-mechanical sources in the presence of a transverse magnetic field. As an application of the approach, the sources are taken as uniformly or linearly distributed. Laplace and Fourier transform techniques are used to solve the problem. The integral transforms have been inverted by using a numerical technique to obtain the components of normal strain, normal stress, tangential couple stress, and temperature distribution in the physical domain. Magnetic effects on the components of normal strain, normal stress, tangential couple stress, and temperature distribution have been depicted graphically for two different theories of generalized thermoelasticity, Lord and Shulman (L-S) theory and Green and Lindsay (G-L) theory. A particular case of interest is also deduced from the present investigation.

  13. Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    NASA Technical Reports Server (NTRS)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2002-01-01

    Thick rubber components are employed by the Army to carry large loads. In tanks, rubber covers road wheels and track systems to protect roadways. It is difficult for design engineers to simulate the details of the hysteretic heating for large strain viscoelastic deformations. In this study, an approximation to the viscoelastic energy dissipated per unit time is investigated for use in estimating mechanically induced viscoelastic heating. Coupled thermo-mechanical simulations of large cyclic deformations of rubber cylinders are presented. The cylinders are first compressed axially and then cyclically loaded about the compressed state. Details of the algorithm and some computational issues are discussed. The coupled analyses are conducted for tall and short rubber cylinders both with and without imbedded metal disks.

  14. A Transversely Isotropic Thermo-mechanical Framework for Oil Shale

    NASA Astrophysics Data System (ADS)

    Semnani, S. J.; White, J. A.; Borja, R. I.

    2014-12-01

    The present study provides a thermo-mechanical framework for modeling the temperature dependent behavior of oil shale. As a result of heating, oil shale undergoes phase transformations, during which organic matter is converted to petroleum products, e.g. light oil, heavy oil, bitumen, and coke. The change in the constituents and microstructure of shale at high temperatures dramatically alters its mechanical behavior e.g. plastic deformations and strength, as demonstrated by triaxial tests conducted at multiple temperatures [1,2]. Accordingly, the present model formulates the effects of changes in the chemical constituents due to thermal loading. It is well known that due to the layered structure of shale its mechanical properties in the direction parallel to the bedding planes is significantly different from its properties in the perpendicular direction. Although isotropic models simplify the modeling process, they fail to accurately describe the mechanical behavior of these rocks. Therefore, many researchers have studied the anisotropic behavior of rocks, including shale [3]. The current study presents a framework to incorporate the effects of transverse isotropy within a thermo-mechanical formulation. The proposed constitutive model can be readily applied to existing finite element codes to predict the behavior of oil shale in applications such as in-situ retorting process and stability assessment in petroleum reservoirs. [1] Masri, M. et al."Experimental Study of the Thermomechanical Behavior of the Petroleum Reservoir." SPE Eastern Regional/AAPG Eastern Section Joint Meeting. Society of Petroleum Engineers, 2008. [2] Xu, B. et al. "Thermal impact on shale deformation/failure behaviors---laboratory studies." 45th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, 2011. [3] Crook, AJL et al. "Development of an orthotropic 3D elastoplastic material model for shale." SPE/ISRM Rock Mechanics Conference. Society of Petroleum Engineers

  15. Newer Concepts in Mars Exploration; LORPEX and PV Enhanced Aerobots

    NASA Astrophysics Data System (ADS)

    Ramohalli, Kumar; Natale, Guy; Marcozzi, Massimiliano; Greene, Jack; Duke, Vanessa

    2002-01-01

    This paper describes two new concepts in Mars Exploration, both of which involve the utilization of in-situ resources. In the first invention, we describe a Locally Refueled Planetary Explorer (LORPEX) which has practically unlimited range and life since it "lives off the land/atmosphere" by extracting fuel and oxidizer from the atmosphere, and possibly water at a later stage, as a source of hydrogen. The robot has been built and demonstrated to the media, including one science show in Pasadena. In the second invention, the concept is to obviate the difficulty of finding a suitable, lightweight substrate to bond the photovoltaic cells to; if we have an aerobot anyway for covering vast terrains, the balloon surface provides an ideal substrate for the PV cells at a minimal additional mass. Because of the truly large areas, and because sun-pointing is no longer a factor, the power availability is constant and represents at least a ten-fold increase over comparable/competing technologies; when this is combined with the minimum mass, the advantages should be apparent. Both of these technologies, LORPEX and PV-Enhanced Aerobots, won NASA NTR awards.

  16. High Temperature Near-Field NanoThermoMechanical Rectification

    NASA Astrophysics Data System (ADS)

    Elzouka, Mahmoud; Ndao, Sidy

    2017-03-01

    Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies. In the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. However, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. Here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (NFTR) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments. We achieved rectification through the coupling between NFTR and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. We fabricated and tested a proof-of-concept NanoThermoMechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 K. Experimentally, we operated the microdevice in temperatures as high as about 600 K, demonstrating this technology’s suitability to operate at high temperatures.

  17. High Temperature Near-Field NanoThermoMechanical Rectification

    PubMed Central

    Elzouka, Mahmoud; Ndao, Sidy

    2017-01-01

    Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies. In the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. However, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. Here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (NFTR) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments. We achieved rectification through the coupling between NFTR and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. We fabricated and tested a proof-of-concept NanoThermoMechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 K. Experimentally, we operated the microdevice in temperatures as high as about 600 K, demonstrating this technology’s suitability to operate at high temperatures. PMID:28322324

  18. Boundary characterization of microstructures through thermo-mechanical testing

    NASA Astrophysics Data System (ADS)

    Rinaldi, G.; Packirisamy, M.; Stiharu, I.

    2006-03-01

    A variety of silicon foundry processes available for microsystem implementation are available at the present time. The manufacturing methods and the associated process tolerances employed at a particular foundry will determine the performance of the finished devices. Moreover, micro-electro-mechanical systems (MEMS) often require processes that are difficult to control. Device-to-device variations can occur even in batch microfabricated systems. One particular limitation of MEMS foundry processes, in general, is associated with non-classical boundary support conditions due to over/under etching of silicon. These non-classical support conditions will affect the static and dynamic performance of the microsystem. This condition has important implications in atomic force microscopy applications where the targeted natural frequencies are given a wide tolerance due in large part to microfabrication limitations. This paper presents the boundary characterization of single crystal silicon microcantilevers through thermo-mechanical testing. A non-contact optical sensing approach is used for the experimentation. The Rayleigh-Ritz energy method incorporating boundary characteristic orthogonal polynomials is used for the prediction analysis.

  19. GaN-on-diamond electronic device reliability: Mechanical and thermo-mechanical integrity

    SciTech Connect

    Liu, Dong; Sun, Huarui; Pomeroy, James W.; Kuball, Martin; Francis, Daniel; Faili, Firooz; Twitchen, Daniel J.

    2015-12-21

    The mechanical and thermo-mechanical integrity of GaN-on-diamond wafers used for ultra-high power microwave electronic devices was studied using a micro-pillar based in situ mechanical testing approach combined with an optical investigation of the stress and heat transfer across interfaces. We find the GaN/diamond interface to be thermo-mechanically stable, illustrating the potential for this material for reliable GaN electronic devices.

  20. Robust transition control of a Martian coaxial tiltrotor aerobot

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Underwood, Craig

    2014-06-01

    Hyperion is an autonomous solar-electric powered coaxial tiltrotor aerobot proposed to investigate the Isidis Planitia region on Mars. The objective of this paper is to propose a robust control strategy for transition flight between hover and cruise based on the supervisory control method and the linear robust control method. The proposed transition controller has two levels. The lower level is a series of candidate controllers for the subproblems, which are obtained by the operation of divide and conquer. The higher level uses the state variables to determine which lower level candidate controller should be used. The candidate controllers are solved using the μ synthesis and the conventional longitudinal and lateral control loops. The robustness of the candidate controllers is guaranteed by the robust control theory. The stability and robustness of the transition controller is determined by the switch logic in the higher level. The stability of the proposed control strategy is analyzed. A 6 Degree of Freedom simulation with uncertain aerodynamic model is used to show the robustness and the performance of the proposed controller.

  1. Shape memory behavior of epoxy-based model materials: Tailoring approaches and thermo-mechanical modeling

    NASA Astrophysics Data System (ADS)

    Pandini, Stefano; Avanzini, Andrea; Battini, Davide; Berardi, Mario; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    A series of structurally related epoxy resins were prepared as model systems for the investigation of the shape memory response, with the aim to assess the possibility of tailoring their thermo-mechanical response and conveniently describing their strain evolution under triggering stimuli with a simple thermoviscoelastic model. The resins formulation was varied in order to obtain systems with controlled glass transition temperature and crosslink density. The shape memory response was investigated by means of properly designed thermo-mechanical cycles, which allowed to measure both the ability to fully recover the applied strain and to exert a stress on a confining medium. The results were also compared with the predictions obtained by finite element simulations of the thermo-mechanical cycle by the employ of a model whose parameters were implemented from classical DMA analysis.

  2. Effects of Microstructural Variability on Thermo-Mechanical Properties of a Woven Ceramic Matrix Composite

    NASA Technical Reports Server (NTRS)

    Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

    2013-01-01

    The objectives of this paper include identifying important architectural parameters that describe the SiC/SiC five-harness satin weave composite and characterizing the statistical distributions and correlations of those parameters from photomicrographs of various cross sections. In addition, realistic artificial cross sections of a 2D representative volume element (RVE) are generated reflecting the variability found in the photomicrographs, which are used to determine the effects of architectural variability on the thermo-mechanical properties. Lastly, preliminary information is obtained on the sensitivity of thermo-mechanical properties to architectural variations. Finite element analysis is used in combination with a response surface and it is shown that the present method is effective in determining the effects of architectural variability on thermo-mechanical properties.

  3. Application of Thermo-Mechanical Measurements of Plastic Packages for Reliability Evaluation of PEMS

    NASA Technical Reports Server (NTRS)

    Sharma, Ashok K.; Teverovsky, Alexander

    2004-01-01

    Thermo-mechanical analysis (TMA) is typically employed for measurements of the glass transition temperature (Tg) and coefficients of thermal expansion (CTE) in molding compounds used in plastic encapsulated microcircuits (PEMs). Application of TMA measurements directly to PEMs allows anomalies to be revealed in deformation of packages with temperature, and thus indicates possible reliability concerns related to thermo-mechanical integrity and stability of the devices. In this work, temperature dependencies of package deformation were measured in several types of PEMs that failed environmental stress testing including temperature cycling, highly accelerated stress testing (HAST) in humid environments, and bum-in (BI) testing. Comparison of thermo-mechanical characteristics of packages and molding compounds in the failed parts allowed for explanation of the observed failures. The results indicate that TMA of plastic packages might be used for quality evaluation of PEMs intended for high-reliability applications.

  4. Shape memory alloy nanostructures with coupled dynamic thermo-mechanical effects

    NASA Astrophysics Data System (ADS)

    Dhote, R. P.; Gomez, H.; Melnik, R. N. V.; Zu, J.

    2015-07-01

    Employing the Ginzburg-Landau phase-field theory, a new coupled dynamic thermo-mechanical 3D model has been proposed for modeling the cubic-to-tetragonal martensitic transformations in shape memory alloy (SMA) nanostructures. The stress-induced phase transformations and thermo-mechanical behavior of nanostructured SMAs have been investigated. The mechanical and thermal hysteresis phenomena, local non-uniform phase transformations and corresponding non-uniform temperatures and deformations' distributions are captured successfully using the developed model. The predicted microstructure evolution qualitatively matches with the experimental observations. The developed coupled dynamic model has provided a better understanding of underlying martensitic transformation mechanisms in SMAs, as well as their effect on the thermo-mechanical behavior of nanostructures.

  5. Thermo-Mechanical Behaviour of Turbine Disc Assembly in the Presence of Residual Stresses

    NASA Astrophysics Data System (ADS)

    Maricic, Luke Anthony

    A comprehensive three dimensional coupled thermo-mechanical finite element study is performed on turbine blade attachments in gas turbine engines. The effects of the self-generated centrifugal forces of the disc and the associated blades, thermal loads, and shot peening residual are all considered in this thesis. Three aspects of the work were accordingly examined. The first was concerned with the coupled thermo-mechanical stress analysis and load sharing between the teeth of the fir-tree root. The second was devoted to the development of a complete model incorporating the effect of shot peening residual stresses upon the developed stress state. The effectiveness of shot peening treatment in response to cyclic thermo-mechanical loadings at the contact interface has also been studied. The third was concerned with the validation of some aspects of the developed models analytically using closed form solutions and experimentally using photoelasticity.

  6. Innovative plasticized alginate obtained by thermo-mechanical mixing: Effect of different biobased polyols systems.

    PubMed

    Gao, Chengcheng; Pollet, Eric; Avérous, Luc

    2017-02-10

    Plasticized alginate films with different biobased polyols (glycerol and sorbitol) and their mixtures were successfully prepared by thermo-mechanical mixing instead of the usual casting-evaporation procedure. The microstructure and properties of the different plasticized alginate formulations were investigated by SEM, FTIR, XRD, DMTA and uniaxial tensile tests. SEM and XRD results showed that native alginate particles were largely destructured with the plasticizers (polyols and water), under a thermo-mechanical input. With increasing amount of plasticizers, the samples showed enhanced homogeneity while their thermal and mechanical properties decreased. Compared to sorbitol, glycerol resulted in alginate films with a higher flexibility due to its better plasticization efficiency resulting from its smaller size and higher hydrophilic character. Glycerol and sorbitol mixtures seemed to be an optimum to obtain the best properties. This work showed that thermo-mechanical mixing is a promising method to produce, at large scale, plasticized alginate-based films with improved properties.

  7. Thermo-Mechanical Properties of Alumina Films Created Using the Atomic Layer Deposition Technique

    DTIC Science & Technology

    2010-01-01

    Miller, R.R. Foster, S.H. Jen, J.A. Bertrand, D. Seghete, B.H. Yoon, Y.C. Lee, S.M. George, M.L. Dunn, Thermo-mechanical properties of aluminum ...homepage: www.e lsev ier .com/ locate /sna Thermo-mechanical properties of alumina films created using the atomic layer deposition technique David C...form 11 September 2010 Accepted 22 September 2010 Available online 29 September 2010 Keywords: Thin film Mechanical properties Reliability Robustness a

  8. Coupled infrared laser-thermo-mechanical response of RDX-PCTFE energetic aggregates

    NASA Astrophysics Data System (ADS)

    Brown, Judith A.; Zikry, M. A.

    2016-04-01

    A computational approach is developed to investigate the coupled phenomena of high frequency electromagnetic (EM) wave propagation, laser heat absorption, thermal conduction, and inelastic dynamic thermo-mechanical deformation in heterogeneous energetic materials. The method is used to study hot spot formation in RDX-PCTFE aggregates subjected to high strain rate loads and infrared laser irradiation. The approach couples Maxwell's equations with a dislocation density-based crystal plasticity formulation within a nonlinear finite-element approach to predict and understand thermo-mechanical response due to the interrelated effects of dielectric heating, adiabatic heating, thermal decomposition, and heat conduction. RDX crystalline interfaces and orientations, polymer binder, inelastic strains, dislocation-density evolution, and voids significantly affected the coupled EM-thermo-mechanical response. EM and thermo-mechanical mismatches at interfaces between RDX crystals, binder, and voids resulted in localized regions with high electric field and laser heat generation rates, which subsequently led to hot spot formation. It is predicted that incident laser intensity and plastic shear strain localization are the dominant mechanisms that lead to hot spot formation.

  9. Thermo-mechanical stress analysis of cryopreservation in cryobags and the potential benefit of nanowarming.

    PubMed

    Solanki, Prem K; Bischof, John C; Rabin, Yoed

    2017-02-10

    Cryopreservation by vitrification is the only promising solution for long-term organ preservation which can save tens of thousands of lives across the world every year. One of the challenges in cryopreservation of large-size tissues and organs is to prevent fracture formation due to the tendency of the material to contract with temperature. The current study focuses on a pillow-like shape of a cryobag, while exploring various strategies to reduce thermo-mechanical stress during the rewarming phase of the cryopreservation protocol, where maximum stresses are typically found. It is demonstrated in this study that while the level of stress may generally increase with the increasing amount of CPA filled in the cryobag, the ratio between width and length of the cryobag play a significant role. Counterintuitively, the overall maximum stress is not found when the bag is filled to its maximum capacity (when the filled cryobag resembles a sphere). Parametric investigation suggests that reducing the initial rewarming rate between the storage temperature and the glass transition temperature may dramatically decrease the thermo-mechanical stress. Adding a temperature hold during rewarming at the glass transition temperature may reduce the thermo-mechanical stress in some cases, but may have an adverse effect in other cases. Finally, it is demonstrated that careful incorporation of volumetric heating by means on nanoparticles in an alternating magnetic field, or nanowarming, can dramatically reduce the resulting thermo-mechanical stress. These observations display the potential benefit of a thermo-mechanical design of the cryopreservation protocols in order to prevent structural damage.

  10. Detailed exploration of Titan with a Montgolfiere aerobot

    NASA Astrophysics Data System (ADS)

    Spilker, T.; Tipex Team

    The International Cassini/Huygens (CH) mission has verified the expectation that Saturn's moon Titan offers many opportunities for studying high-priority planetary and astrobiology science objectives. CH results to date show that this world, though entirely alien in its frigid environment, presents an Earth-like and diverse appearance due to the relative balance of competing forces such as geology/tectonics, meteorology, aeronomy, and cosmic impacts. But with the limitations of a single Huygens probe, and a finite number of Cassini flybys limited in proximity and remote sensing resolution by Titan's thick atmosphere and hazes, there is much science to be done there after the CH mission has ended. Detailed exploration of Titan's surface and lower atmosphere, especially for astrobiological objectives, is best addressed by in situ investigations. The atmosphere and its hazes severely restrict orbital remote sensing: Titan cannot be mapped from orbit in the same manner as Mars, at (essentially) arbitrarily high resolution, and limited infrared (IR) windows allow only gross compositional interpretations. After CH indeed there will be further orbital investigations to be carried out, notably completion of the global mapping by Synthetic Aperture Radar and IR mapping spectrometry begun by CH, at the best resolutions practical from orbit. But to fully understand Titan as an evolving, planetary-scale body and an abode of preserved protobiological chemistry will require a platform that has access to, and mobility at, the surface and the lowest few kilometers of the atmosphere. The TiPEx study team weighed the options for Titan in situ exploration, and finds that a mission based on a Montgolfiere (a type of hot-air balloon) aerobot is the best candidate for post-CH exploration. Ground-based platforms of the type used to date on Mars are far too limited in range to sample the diversity of Titan, and do not adequately investigate the lower atmosphere. Titan's cold, dense

  11. Thermo-Mechanical Stress in High-Frequency Vacuum Electron Devices

    NASA Astrophysics Data System (ADS)

    Gamzina, Diana; Luhmann, Neville C.; Ravani, Bahram

    2017-01-01

    Analysis of the thermo-mechanical performance of high-frequency vacuum electron devices is essential to the advancement of RF sources towards high-power generation. Operation in an ultra-high vacuum environment, space restricting magnetic focusing, and limited material options are just some of the constraints that complicate thermal management in a high-power VED. An analytical method for evaluating temperature, stress, and deformation distribution in thin vacuum-to-cooling walls is presented, accounting for anisotropic material properties. Thin plate geometry is used and analytical expressions are developed for thermo-mechanical analysis that includes the microstructure effects of grain orientations. The method presented evaluates the maximum allowable heat flux that can be used to establish the power-handling limitation of high-frequency VEDs prior to full-scale design, accelerating time-to-manufacture.

  12. Description of the performances of a thermo-mechanical energy harvester using bimetallic beams

    NASA Astrophysics Data System (ADS)

    Arnaud, A.; Boughaleb, J.; Monfray, S.; Boeuf, F.; Cugat, O.; Skotnicki, T.

    2016-06-01

    Many recent researches have been focused on the development of thermal energy harvesters using thermo-mechanical or thermo-electrical coupling phenomena associated to a first-order thermodynamic transition. In the case of the bimetallic strip heat engine, the exploitation of the thermo-mechanical instability of bimetallic membranes placed in a thermal gradient enables to convert heat into kinetic energy. This paper is a contribution to the modeling and the comprehension of these heat engines. By restraining the study to the simply-supported bimetallic beams and using a Ritz approximation of the beam shape, this paper aims to give an analytical solution to the first mode of the composite beams and then to evaluate the efficiency of the harvesters exploiting these kinds of instability.

  13. Heat generation and thermo-mechanical effect modeling in longitudinally diode-pumped solid state lasers

    NASA Astrophysics Data System (ADS)

    Lakhdari, Fouad; Osmani, Ismahen; Tabet, Saida

    2015-09-01

    Thermal management in solid state laser is a challenge to the high power laser industry's ability to provide continued improvements in device and system performance. In this work an investigation of heat generation and thermo-mechanical effect in a high-power Nd:YAG and Yb:YAG cylindrical-type solid state laser pumped longitudinally with different power by fibre coupled laser diode is carried out by numerical simulation based on the finite element method (FEM). Impact of the dopant concentration on the power conversion efficiency is included in the simulation. The distribution of the temperature inside the lasing material is resolute according to the thermal conductivity. The thermo-mechanical effect is explored as a function of pump power in order to determine the maximum pumping power allowed to prevent the crystal's fracture. The presented simulations are in broad agreement with analytical solutions; provided that the boundary condition of the pump induced heat generation is accurately modelled.

  14. The development and production of thermo-mechanically forged tool steel spur gears

    NASA Technical Reports Server (NTRS)

    Bamberger, E. N.

    1973-01-01

    A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

  15. A study of thermo-mechanical stress and its impact on through-silicon vias

    NASA Astrophysics Data System (ADS)

    Ranganathan, N.; Prasad, K.; Balasubramanian, N.; Pey, K. L.

    2008-07-01

    The BOSCH etch process, which is commonly used in microelectromechanical system fabrication, has been extensively investigated in this work for implementation in through-silicon via (TSV) technology for 3D-microsystems packaging. The present work focuses on thermo-mechanical stresses caused by thermal loading due to post-TSV processes and their impact on the electrical performance of through-silicon copper interconnects. A test vehicle with deep silicon copper-plated comb structure was designed to study and evaluate different deep silicon via etch processes and its effect on the electrical leakage characteristics under various electrical and thermal stress conditions. It has been shown that the leakage current between the comb interconnect structures increases with an increase in sidewall roughness and that it can be significantly lowered by smoothening the sidewalls. It was also shown that by tailoring a non-BOSCH etch process with the normal BOSCH process, a similar leakage current reduction can be achieved. It was also shown through thermo-mechanical simulation studies that there is a clear correlation between high leakage current behavior due to non-uniform Ta barrier deposition over the rough sidewalls and the thermo-mechanical stress induced by post-TSV processes.

  16. A thermo-mechanical stress prediction model for contemporary planar sodium sulfur (NaS) cells

    NASA Astrophysics Data System (ADS)

    Jung, Keeyoung; Colker, Jeffrey P.; Cao, Yuzhe; Kim, Goun; Park, Yoon-Cheol; Kim, Chang-Soo

    2016-08-01

    We introduce a comprehensive finite-element analysis (FEA) computational model to accurately predict the thermo-mechanical stresses at heterogeneous joints and components of large-size sodium sulfur (NaS) cells during thermal cycling. Quantification of the thermo-mechanical stress is important because the accumulation of stress during cell assembly and/or operation is one of the critical issues in developing practical planar NaS cells. The computational model is developed based on relevant experimental assembly and operation conditions to predict the detailed stress field of a state-of-the-art planar NaS cell. Prior to the freeze-and-thaw thermal cycle simulation, residual stresses generated from the actual high temperature cell assembly procedures are calculated and implemented into the subsequent model. The calculation results show that large stresses are developed on the outer surface of the insulating header and the solid electrolyte, where component fracture is frequently observed in the experimental cell fabrication process. The impacts of the coefficients of thermal expansion (CTE) of glass materials and the thicknesses of cell container on the stress accumulation are also evaluated to improve the cell manufacturing procedure and to guide the material choices for enhanced thermo-mechanical stability of large-size NaS cells.

  17. Multiscale Thermo-Mechanical Design and Analysis of High Frequency and High Power Vacuum Electron Devices

    NASA Astrophysics Data System (ADS)

    Gamzina, Diana

    Diana Gamzina March 2016 Mechanical and Aerospace Engineering Multiscale Thermo-Mechanical Design and Analysis of High Frequency and High Power Vacuum Electron Devices Abstract A methodology for performing thermo-mechanical design and analysis of high frequency and high average power vacuum electron devices is presented. This methodology results in a "first-pass" engineering design directly ready for manufacturing. The methodology includes establishment of thermal and mechanical boundary conditions, evaluation of convective film heat transfer coefficients, identification of material options, evaluation of temperature and stress field distributions, assessment of microscale effects on the stress state of the material, and fatigue analysis. The feature size of vacuum electron devices operating in the high frequency regime of 100 GHz to 1 THz is comparable to the microstructure of the materials employed for their fabrication. As a result, the thermo-mechanical performance of a device is affected by the local material microstructure. Such multiscale effects on the stress state are considered in the range of scales from about 10 microns up to a few millimeters. The design and analysis methodology is demonstrated on three separate microwave devices: a 95 GHz 10 kW cw sheet beam klystron, a 263 GHz 50 W long pulse wide-bandwidth sheet beam travelling wave tube, and a 346 GHz 1 W cw backward wave oscillator.

  18. Effect of Water on the Thermo-Mechanical Behavior of Carbon Cloth Phenolic

    NASA Technical Reports Server (NTRS)

    Sullivan, Roy M.; Stokes, Eric; Baker, Eric H.

    2011-01-01

    The results of thermo-mechanical experiments, which were conducted previously by one of the authors, are reviewed. The strain in the direction normal to the fabric plane was measured as a function of temperature for a variety of initial moisture contents and heating rates. In this paper, the general features of the thermo-mechanical response are discussed and the effect of heating rate and initial moisture content are highlighted. The mechanical interaction between the phenolic polymer and water trapped within its free volumes as the polymer is heated to high temperatures is discussed. An equation for the internal stresses which are generated within the polymer due to trapped water is obtained from the total stress expression for a binary mixture of polymer and water. Numerical solutions for moisture diffusion in the thermo-mechanical experiments were performed and the results of these solutions are presented. The results of the moisture diffusion solutions help to explain the effects of heating rate and moisture content on the strain behavior normal to the fabric plane.

  19. Assessing thermo-mechanical properties of the lithospheric mantle in Asia

    NASA Astrophysics Data System (ADS)

    Stolk, W.; Kaban, M. K.; Beekman, F.; Tesauro, M.; Cloetingh, S.

    2012-12-01

    Asia is a key natural laboratory for the study of active intra-continental deformation in response to the ongoing far-field collision of India and Eurasia. The resulting tectonic processes strongly depend on the thermo-mechanical structure of the lithosphere. However, the problem of the thermo-mechanical properties of the lithospheric mantle is complex and still not well resolved. While seismic studies give an indication of the heterogeneity of the mantle lithosphere it alone is insufficient to attribute these anomalies to thermal differences, since compositional difference may have a significant effect on observed wave velocities. Using solely gravity field analysis one cannot distinguish between e.g. stacked density anomalies or lateral density anomalies. Combining both datasets allows for a better insight into the mantle lithosphere, though the solution to the problem at hand remains non-unique. This study, of which the preliminary results will be presented here, attempts to gain insight into both compositional and thermal aspects of the mantle lithosphere in Asia. By combining a recent high resolution tomographic inversion with gravity field data, but without the assumption of a steady state mantle, a trade off between compositional and thermal effects can be made. Furthermore, susceptibility of the resulting model to small changes in parameter space can be obtained thus creating a 'playing field' for possible solutions to the thermo-mechanical problem. This 'playing field' can be further constrained by additional data from other sources, such as xenolith studies.

  20. Interactive evolution concept for analyzing a rock salt cavern under cyclic thermo-mechanical loading

    NASA Astrophysics Data System (ADS)

    König, Diethard; Mahmoudi, Elham; Khaledi, Kavan; von Blumenthal, Achim; Schanz, Tom

    2016-04-01

    The excess electricity produced by renewable energy sources available during off-peak periods of consumption can be used e.g. to produce and compress hydrogen or to compress air. Afterwards the pressurized gas is stored in the rock salt cavities. During this process, thermo-mechanical cyclic loading is applied to the rock salt surrounding the cavern. Compared to the operation of conventional storage caverns in rock salt the frequencies of filling and discharging cycles and therefore the thermo-mechanical loading cycles are much higher, e.g. daily or weekly compared to seasonally or yearly. The stress strain behavior of rock salt as well as the deformation behavior and the stability of caverns in rock salt under such loading conditions are unknown. To overcome this, existing experimental studies have to be supplemented by exploring the behavior of rock salt under combined thermo-mechanical cyclic loading. Existing constitutive relations have to be extended to cover degradation of rock salt under thermo-mechanical cyclic loading. At least the complex system of a cavern in rock salt under these loading conditions has to be analyzed by numerical modeling taking into account the uncertainties due to limited access in large depth to investigate material composition and properties. An interactive evolution concept is presented to link the different components of such a study - experimental modeling, constitutive modeling and numerical modeling. A triaxial experimental setup is designed to characterize the cyclic thermo-mechanical behavior of rock salt. The imposed boundary conditions in the experimental setup are assumed to be similar to the stress state obtained from a full-scale numerical simulation. The computational model relies primarily on the governing constitutive model for predicting the behavior of rock salt cavity. Hence, a sophisticated elasto-viscoplastic creep constitutive model is developed to take into account the dilatancy and damage progress, as well as

  1. Correlation of microstructure and thermo-mechanical properties of a novel hydrogen transport membrane

    NASA Astrophysics Data System (ADS)

    Zhang, Yongjun

    A key part of the FutureGen concept is to support the production of hydrogen to fuel a "hydrogen economy," with the use of clean burning hydrogen in power-producing fuel cells, as well as for use as a transportation fuel. One of the key technical barriers to FutureGen deployment is reliable and efficient hydrogen separation technology. Most Hydrogen Transport Membrane (HTM) research currently focuses on separation technology and hydrogen flux characterization. No significant work has been performed on thermo-mechanical properties of HTMs. The objective of the thesis is to understand the structure-property correlation of HTM and to characterize (1) thermo mechanical properties under different reducing environments and thermal cycles (thermal shock), and (2) evaluate the stability of the novel HTM material. A novel HTM cermet bulk sample was characterized for its physical and mechanical properties at both room temperature and at elevated temperature up to 1000°C. Micro-structural properties and residual stresses were evaluated in order to understand the changing mechanism of the microstructure and its effects on the mechanical properties of materials. A correlation of the microstructural and thermo mechanical properties of the HTM system was established for both HTM and the substrate material. Mechanical properties of both selected structural ceramics and the novel HTM cermet bulk sample are affected mainly by porosity and microstructural features, such as grain size and pore size-distribution. The Young's Modulus (E-value) is positively correlated to the flexural strength for materials with similar crystallographic structure. However, for different crystallographic materials, physical properties are independent of mechanical properties. Microstructural properties, particularly, grain size and crystallographic structure, and thermodynamic properties are the main factors affecting the mechanical properties at both room and high temperatures. The HTM cermet behaves

  2. User-defined Material Model for Thermo-mechanical Progressive Failure Analysis

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.

    2008-01-01

    Previously a user-defined material model for orthotropic bimodulus materials was developed for linear and nonlinear stress analysis of composite structures using either shell or solid finite elements within a nonlinear finite element analysis tool. Extensions of this user-defined material model to thermo-mechanical progressive failure analysis are described, and the required input data are documented. The extensions include providing for temperature-dependent material properties, archival of the elastic strains, and a thermal strain calculation for materials exhibiting a stress-free temperature.

  3. Modelling the Thermo-Mechanical Behavior of Magnesium Alloys during Indirect Extrusion

    SciTech Connect

    Steglich, D.; Ertuerk, S.; Bohlen, J.; Letzig, D.; Brocks, W.

    2010-06-15

    One of the basic metal forming process for semi-finished products is extrusion. Since extrusion involves complex thermo-mechanical and multiaxial loading conditions resulting in large strains, high strain rates and an increase in temperature due to deformation, a proper yield criterion and hardening law should be used in the numerical modelling of the process. A phenomenological model based on a plastic potential has been proposed that takes strain, strain rate and temperature dependency on flow behaviour into consideration. A hybrid methodology of experiment and finite element simulation has been adopted in order to obtain necessary model parameters. The anisotropy/asymmetry in yielding was quantified by tensile and compression tests of specimens prepared from different directions. The identification of the corresponding model parameters was performed by a genetic algorithm. A fully coupled thermo-mechanical analysis has been used in extrusion simulations for calculation of the temperature field by considering heat fluxes and heat generated due to plastic deformation. The results of the approach adopted in this study appeared to be successful showing promising predictions of the experiments and thus may be extended to be applicable to other magnesium alloys or even other hcp metals.

  4. Thermo-mechanical simulations of CO2 laser-fused silica interactions

    NASA Astrophysics Data System (ADS)

    Doualle, T.; Gallais, L.; Cormont, P.; Hébert, D.; Combis, P.; Rullier, J.-L.

    2016-03-01

    CO2 laser heating of silica glass is used in many scientific and industrial applications. Particularly, localized CO2 laser heating of silica glass has demonstrated its ability to mitigate surface damage on optics used for high power laser applications. To develop such applications, the control of temperature, heat affected area, and resulting mechanical stresses are critical. Therefore, it is necessary to understand the silica transformation, the material ejection, and the thermo-mechanical stresses induced by the laser heating and subsequent cooling. In this paper, we detail the development of comprehensive thermo-mechanical numerical simulations of these physical processes, based on finite-element method. The approach is developed for 2D or 3D cases to tackle the case of a moving beam at the surface of the sample, and we particularly discuss the choice of the different parameters based on bibliographic inputs. The thermal and mechanical numerical results have been compared to different dedicated experimental studies: infrared thermography measurements at the surface of the irradiated area, optical profilometry measurements of the laser-processed sites, and photo-elastic measurements. Very consistent results are obtained between numerical and experimental results for the description of the temperature gradients, the material ejection, and the residual stresses.

  5. A thermodynamic theory for characterizing thermo-mechanical response of polymers during crystallization

    SciTech Connect

    Negahban, M.

    1995-12-31

    A thermodynamic theory will be presented to capture the thermo-mechanical characteristics associated with crystallization of polymers. The basic characteristics associated with crystallization consists of (a) crystallization in polymers is considered a gradual transition from an amorphous polymer to a semi-crystalline polymer, (b) there is a volume reduction associated with crystallization as the material moves to the denser morphology of the crystal structure, (c) there is a substantial stiffening of the polymer, (d) there is stress relaxation associated with crystallization for polymers under a constant stretch, (e) there is creep associated with crystallization in polymers under a fixed load. These and other characteristics are modeled in a multi-dimensional thermodynamic theory. As a first example, the simplest possible constitutive assumptions are studied in relation to characterizing the behavior of natural rubber. Natural rubber is selected due to the abundance of information on its thermo-mechanical behavior. This work is an extension to non-isothermal thermodynamic processes of previous work on characterizing the mechanical effects of polymer crystallization under isothermal conditions.

  6. Damage mechanisms in PBT-GF30 under thermo-mechanical cyclic loading

    SciTech Connect

    Schaaf, A. De Monte, M. Hoffmann, C.; Vormwald, M.; Quaresimin, M.

    2014-05-15

    The scope of this paper is the investigation of damage mechanisms at microscopic scale on a short glass fiber reinforced polybutylene terephthalate (PBT-GF30) under thermo-mechanical cyclic loading. In addition the principal mechanisms are verified through micro mechanical FE models. In order to investigate the fatigue behavior of the material both isothermal strain controlled fatigue (ISCF) tests at three different temperatures and thermo-mechanical fatigue (TMF) tests were conducted on plain and notched specimens, manufactured by injection molding. The goal of the work is to determine the damage mechanisms occurring under TMF conditions and to compare them with the mechanisms occurring under ISCF. For this reason fracture surfaces of TMF and ISCF samples loaded at different temperature levels were analyzed using scanning electron microscopy. Furthermore, specimens that failed under TMF were examined on microsections revealing insight into both crack initiation and crack propagation. The findings of this investigation give valuable information about the main damage mechanisms of PBT-GF30 under TMF loading and serve as basis for the development of a TMF life estimation methodology.

  7. Effect of Thermo-mechanical Load Cycling on Microleakage in Class II Ormocer Restorations

    PubMed Central

    Erdilek, Dina; Dörter, Can; Koray, Fatma; Kunzelmann, Karl-Heinz; Efes, Begum Guray; Gomec, Yavuz

    2009-01-01

    Objectives The objective of this in vitro study was to evaluate the marginal sealing ability of an ormocer in comparison with a hybrid composite when using thermocycling and load cycling procedures together in the study design. Methods Modified proximal Class II cavities were prepared on the mesial and distal surfaces of twenty-two human premolars. Each tooth was restored with Admira and contralaterally with TPH Spectrum. Half of all of the teeth were subjected to thermo-mechanical load cycling. After dye penetration, longitudinal sections in mesio-distal direction were prepared and examined under a stereomicroscope. Data were analyzed with Mann Whitney U test. Results The results showed that the thermo-mechanical load cycling caused a statistically significant increase in gingival microleakage when compared with the non-thermocycled and non-loaded restorations for both the materials Admira (P=0.006) and TPH Spectrum (P=0.023). Conclusions Simultaneous load cycling and thermocycling are decisive factors in the in vitro assessment of gingival microleakage, which still remains to be a clinical problem even with the ormocer system Admira. PMID:19756194

  8. Three-dimensional EBSD characterization of thermo-mechanical fatigue crack morphology in compacted graphite iron

    SciTech Connect

    Pirgazi, Hadi; Ghodrat, Sepideh; Kestens, Leo A.I.

    2014-04-01

    In cylinder heads made of compacted graphitic iron (CGI), heating and cooling cycles can lead to localized cracking due to thermo-mechanical fatigue (TMF). To meticulously characterize the complex crack path morphology of CGI under TMF condition, in relation to microstructural features and to find out how and by which mechanisms the cracks predominantly develop, three-dimensional electron back scattering diffraction (EBSD) was employed. Based on the precise quantitative microstructural analysis, it is found that graphite particles not only play a crucial role in the crack initiation, but also are of primary significance for crack propagation, i.e. crack growth is enhanced by the presence of graphite particles. Furthermore, the density of graphite particles on the fracture plane is more than double as high as in any other arbitrary plane of the structure. The obtained results did not indicate a particular crystallographic preference of fracture plane, i.e. the crystal plane parallel to the fracture plane was nearly of random orientation. - Highlights: • Crystallographic features of a thermo-mechanical fatigue (TMF) crack were studied. • Wide-field 3D EBSD is used to characterize the TMF crack morphology. • Data processing was applied on a large length scale of the order of millimeters. • Graphite density in the fracture plane is much higher than any other random plane. • It is revealed that crack growth is enhanced by the presence of graphite particles.

  9. Thermo-Mechanical Modeling of Laser-Mig Hybrid Welding (lmhw)

    NASA Astrophysics Data System (ADS)

    Kounde, Ludovic; Engel, Thierry; Bergheau, Jean-Michel; Boisselier, Didier

    2011-01-01

    Hybrid welding is a combination of two different technologies such as laser (Nd: YAG, CO2…) and electric arc welding (MIG, MAG / TIG …) developed to assemble thick metal sheets (over 3 mm) in order to reduce the required laser power. As a matter of fact, hybrid welding is a lso used in the welding of thin materials to benefit from process, deep penetration and gap limit. But the thermo-mechanical behaviour of thin parts assembled by LMHW technology for railway cars production is far from being controlled the modeling and simulation contribute to the assessment of the causes and effects of the thermo mechanical behaviour in the assembled parts. In order to reproduce the morphology of melted and heat-affected zones, two analytic functions were combined to model the heat source of LMHW. On one hand, we applied a so-called "diaboloïd" (DB) which is a modified hyperboloid, based on experimental parameters and the analysis of the macrographs of the welds. On the other hand, we used a so-called "double ellipsoïd" (DE) which takes the MIG only contribution including the bead into account. The comparison between experimental result and numerical result shows a good agreement.

  10. Integrated Radiation Transport and Thermo-Mechanics Simulation of a PWR Assembly

    SciTech Connect

    Clarno, Kevin T; Hamilton, Steven P; Philip, Bobby; Sampath, Rahul S; Allu, Srikanth; Berrill, Mark A; Barai, Pallab; Banfield, James E

    2012-01-01

    The Advanced Multi-Physics (AMP) Nuclear Fuel Performance code (AMPFuel) is focused on predicting the temperature and strain within a nuclear fuel assembly to evaluate the performance and safety of existing and advanced nuclear fuel bundles within existing and advanced nuclear reactors. AMPFuel was extended to include an integrated nuclear fuel assembly capability for (one-way) coupled radiation transport and nuclear fuel assembly thermo-mechanics. This capability is the initial step towards incorporating an improved predictive nuclear fuel assembly modeling capability to accurately account for source terms, such as the neutron flux distribution, coolant conditions, and assembly mechanical stresses, of traditional (single-pin) nuclear fuel performance simulation. AMPFuel was used to model an entire 17 x 17 Pressurized Water Reactor (PWR) fuel assembly with many of the features resolved in three dimensions (for thermo-mechanics and/or neutronics), including the fuel, gap, and cladding of each of the 264 fuel pins, the 25 guide tubes, top and bottom structural regions, and the upper and lower (neutron) reflector regions. The final full-assembly calculation was executed on Jaguar (Cray XT5) at the Oak Ridge Leadership Computing Facility using 40,000 cores in under 10 hours to model over 162 billion degrees of freedom for 10 loading steps.

  11. Thermo-mechanical properties of boron nitride nanoribbons: A molecular dynamics simulation study.

    PubMed

    Mahdizadeh, Sayyed Jalil; Goharshadi, Elaheh K; Akhlamadi, Golnoosh

    2016-07-01

    Thermo-mechanical properties of boron nitride nanoribbons (BNNRs) were computed using molecular dynamics simulation with optimized Tersoff empirical potential. Thermal conductivity (TC) and heat transport properties of BNNRs were calculated as functions of both temperature and nanoribbon's length. The results show that TC of BNNRs decreases with raising temperature by T(-1.5) up to 1000K. The phonon-phonon scattering relaxation time, mean free path of phonons, and contribution of high frequency optical phonons in TC of BNNRs were calculated at various temperatures. TC decreases as nanoribbon size increases and it converges to ∼500Wm(-1)K(-1) for nanoribbons with length longer than 30nm. The mechanical properties, including Gruneisen parameter, stress-strain response curves, Young's modulus, intrinsic strength, critical strain, and poisson's ratio were calculated in the temperature range of 137-1000K. The simulation results show that Gruneisen parameter and poisson's ratio of BNNRs are -0.092 and 0.245, respectively. The Young's modulus of BNNRs decreases with raising temperature and its value is 630GPa at 300K. According to the results, BNNRs duo to their extraordinary thermo-mechanical properties, are the promising candidate for the future nano-device manufacturing.

  12. Determination of hysteresis loops in thermo-mechanical fatigue using isothermal stress-strain data

    NASA Astrophysics Data System (ADS)

    Skelton, R. P.

    1994-04-01

    Thermo-mechanical fatigue stress-strain data on ferritic/austenitic steels and superalloys from a variety of sources are analyzed with regard to hysteresis loop stress asymmetry. This arises from a decoupling of the thermal and mechanical strain signals in the test technique so that many tension-compression load combinations are possible. Data from simplified isothermal and bithermal tests are also examined. Taking a typical example of an 'out-of-phase' thermo-mechanical loop on a 1/2CrMoV steel cycled between 200 and 550 C, isothermal stress-strain data were generated at 50 C intervals on material from the same cast and, used in conjunction with the elastic characteristics of the apparatus, an attempt was made to re-create this loop. The methods employed were: (1) a graphical construction between appropriate isothermal yield contours; (2) a tangent modulus calculation; and (3) a secant modulus calculation. Method (1) appeared to give the closest agreement in the present case.

  13. Thermo-mechanical analysis of FG nanobeam with attached tip mass: an exact solution

    NASA Astrophysics Data System (ADS)

    Ghadiri, Majid; Jafari, Ali

    2016-12-01

    Present disquisition proposes an analytical solution method for exploring the vibration characteristics of a cantilever functionally graded nanobeam with a concentrated mass exposed to thermal loading for the first time. Thermo-mechanical properties of FGM nanobeam are supposed to change through the thickness direction of beam based on the rule of power-law (P-FGM). The small-scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. Linear temperature rise (LTR) through thickness direction is studied. Existence of centralized mass in the free end of nanobeam influences the mechanical and physical properties. Timoshenko beam theory is employed to derive the nonlocal governing equations and boundary conditions of FGM beam attached with a tip mass under temperature field via Hamilton's principle. An exact solution procedure is exploited to achieve the non-dimensional frequency of FG nanobeam exposed to temperature field with a tip mass. A parametric study is led to assess the efficacy of temperature changes, tip mass, small scale, beam thickness, power-law exponent, slenderness and thermal loading on the natural frequencies of FG cantilever nanobeam with a point mass at the free end. It is concluded that these parameters play remarkable roles on the dynamic behavior of FG nanobeam subjected to LTR with a tip mass. The results for simpler states are confirmed with known data in the literature. Presented numerical results can serve as benchmarks for future thermo-mechanical analyses of FG nanobeam with tip mass.

  14. The Effect of Thermo-Mechanical Treatment on Structure of Ultrahigh Carbon PM Steel

    NASA Astrophysics Data System (ADS)

    Nikiel, Piotr; Szczepanik, Stefan; Skrzypek, Stanisław Jan; Rogal, Łukasz

    2017-03-01

    The effects of thermo-mechanical treatment on selected properties related to the structure of Fe-0.85Mo-0.65i-1.4C powder metallurgy (PM) steel are reported. Three kinds of initial microstructure of specimens, i.e., pearlite + ferrite + cementite, martensite + retained austenite and α + spheroidized cementite were examined. Processing was carried out on a plastometer-dilatometer Bähr machine by compression cylindrical specimens at 775 °C at a strain rate of 0.001 s-1. X-ray diffraction was carried out with symmetrical Bragg-Brentano and grazing incident angle methods on a D8-Advance diffractometer with filtered radiation of cobalt CoK α . The following features were determined: texture, density of dislocations, density of vacancies, lattice parameter of Fe α and mean size of crystallites. Significant differences in structure were observed, especially in quenched specimen, as a result of the thermo-mechanical treatment. Regardless of initial state of the specimens, the determined properties were on a similar level. Crystallite size was in the range 97-106 nm, crystallite texture (I{200}/I{110}) × 10 = 1.15-1.62 and density of vacancies I{110}/I{220} = 7.06-7.52.

  15. First principles calculation of thermo-mechanical properties of thoria using Quantum ESPRESSO

    NASA Astrophysics Data System (ADS)

    Malakkal, Linu; Szpunar, Barbara; Zuniga, Juan Carlos; Siripurapu, Ravi Kiran; Szpunar, Jerzy A.

    2016-05-01

    In this work, we have used Quantum ESPRESSO (QE), an open source first principles code, based on density-functional theory, plane waves, and pseudopotentials, along with quasi-harmonic approximation (QHA) to calculate the thermo-mechanical properties of thorium dioxide (ThO2). Using Python programming language, our group developed qe-nipy-advanced, an interface to QE, which can evaluate the structural and thermo-mechanical properties of materials. We predicted the phonon contribution to thermal conductivity (kL) using the Slack model. We performed the calculations within local density approximation (LDA) and generalized gradient approximation (GGA) with the recently proposed version for solids (PBEsol). We employed a Monkhorst-Pack 5 × 5 × 5 k-points mesh in reciprocal space with a plane wave cut-off energy of 150 Ry to obtain the convergence of the structure. We calculated the dynamical matrices of the lattice on a 4 × 4 × 4 mesh. We have predicted the heat capacity, thermal expansion and the phonon contribution to thermal conductivity, as a function of temperature up to 1400K, and compared them with the previous work and known experimental results.

  16. A Thermo-mechanical Framework for Shale Based on Anisotropic Critical State Plasticity

    NASA Astrophysics Data System (ADS)

    Semnani, S. J.

    2015-12-01

    Due to its layered structure at multiple scales, mechanical properties of shale in the direction parallel to the bedding planes are significantly different from its properties in the perpendicular direction. Isotropic material models simplify the process of modeling these materials; however, they often fail to accurately describe mechanical response when the layered structure plays an important role. Further, shales often exhibit temperature-dependent properties when significantly heated or cooled. In this work, we study the thermo-mechanical behavior of oil shale, a kerogen-rich source rock. In particular, we examine in-situ conversion processes in which the shale is heated to high temperatures (>300C) to convert the solid kerogen phase to useful oil and gas products. Multi-temperature triaxial tests on core samples reveal that changes in microstructure at high temperatures dramatically alter mechanical properties. Accordingly, the current study presents a thermo-mechanical framework for modeling oil shale and related materials. The underlying model is based on the well-known Modified Cam-Clay (MCC) yield surface, here modified to incorporate the effects of transverse isotropy. We also include temperature dependence in the elastic and plastic response. The proposed model is verified by comparison with available experimental data, and used to study the effect of anisotropy on deformation behavior during mechanical and thermal loading. We also study the formation of deformation bands as a result material instability, and the effect the bedding structure has on the shear localization process.

  17. Simulation of the PBF-Candu test with coupled thermal-hydraulic and fuel thermo-mechanical responses

    SciTech Connect

    Baschuk, J. J.

    2012-07-01

    During a large loss-of-coolant accident (LLOCA), the fuel sheath temperature is influenced by thermal-hydraulic and thermo-mechanical phenomena. The thermal-hydraulic phenomena include the heat transfer from the sheath to the coolant and surroundings. Thermo-mechanical phenomena, such as creep and thermal expansion, influence the size of the fuel-to-sheath gap, and thus the heat transfer from the fuel to the sheath. Therefore, coupling the thermal-hydraulic and thermo-mechanical analysis of an LLOCA would result in more accurate predictions of sheath temperature. This is illustrated by comparing the sheath temperature predictions from coupled and decoupled simulations of the PBF-Candu Test with experimental measurements. The codes CATHENA and ELOCA were used for the thermal-hydraulic and thermo-mechanical analysis, respectively. The predicted sheath temperatures from both the coupled and decoupled simulations were higher than the measured values. However, after the initial power pulse, when the fuel-to-sheath gap was calculated as being opened, the sheath temperatures predicted by the coupled simulation were closer to the experimental measurements. Thus, under conditions of an open fuel-to-sheath gap, a coupled thermal-hydraulic and thermo-mechanical analysis can improve predictions of sheath temperatures. (authors)

  18. Thermo-mechanical analysis of an internal cooling system with various configurations of a combustion liner after shell

    NASA Astrophysics Data System (ADS)

    Moon, Hokyu; Kim, Kyung Min; Park, Jun Su; Kim, Beom Seok; Cho, Hyung Hee

    2015-12-01

    The after-shell section, which is part of the gas turbine combustion liner, is exposed to the hottest combustion gas. Various cooling schemes have been applied to protect against severe thermal load. However, there is a significant discrepancy in the thermal expansion with large temperature differences, resulting in thermo-mechanical crack formation. In this study, to reduce combustion liner damage, thermo-mechanical analysis was conducted on three after-shell section configurations: inline-discrete divider wall, staggered divider wall, and swirler wall arrays. These array components are well-known heat-transfer enhancement structures in the duct. In the numerical analyses, the heat transfer characteristics, temperature and thermo-mechanical stress distribution were evaluated using finite volume method and finite element method commercial codes. As a result, we demonstrated that the temperature and the thermo-mechanical stress distribution were readily dependent on the structural array for cooling effectiveness and structural support in each modified cooling system. Compared with the reference model, the swirler wall array was most effective in diminishing the thermo-mechanical stress concentration, especially on the inner ring that is vulnerable to crack formation.

  19. An Autonomy Architecture for Aerobot Exploration of the Saturnian Moon Titan

    NASA Technical Reports Server (NTRS)

    Elfes, Alberto; Hall, Jeffery L.; Kulczycki, Eric A.; Clouse, Daniel S.; Morfopoulos, Arin C.; Montgomery, James F.; Cameron, Jonathan M.; Ansar, Adnan; Machuzak, Richard J.

    2008-01-01

    The Huygens probe arrived at Saturn's moon Titan on January 14, 2005, unveiling a world that is radically different from any other in the Solar system. The data obtained, complemented by continuing observations from the Cassini spacecraft, show methane lakes, river channels and drainage basins, sand dunes, cryovolcanos and sierras. This has lead to an enormous scientific interest in a follow-up mission to Titan, using a robotic lighter-than-air vehicle (or aerobot). Aerobots have modest power requirements, can fly missions with extended durations, and have very long distance traverse capabilities. They can execute regional surveys, transport and deploy scientific instruments and in-situ laboratory facilities over vast distances, and also provide surface sampling at strategic science sites. This paper describes our progress in the development of the autonomy technologies that will be required for exploration of Titan. We provide an overview of the autonomy architecture and some of its key components. We also show results obtained from autonomous flight tests conducted in the Mojave desert.

  20. Determination of Constitutive Equation for Thermo-mechanical Processing of INCONEL 718 Through Double Multivariate Nonlinear Regression Analysis

    NASA Astrophysics Data System (ADS)

    Hussain, Mirza Zahid; Li, Fuguo; Wang, Jing; Yuan, Zhanwei; Li, Pan; Wu, Tao

    2015-07-01

    The present study comprises the determination of constitutive relationship for thermo-mechanical processing of INCONEL 718 through double multivariate nonlinear regression, a newly developed approach which not only considers the effect of strain, strain rate, and temperature on flow stress but also explains the interaction effect of these thermo-mechanical parameters on flow behavior of the alloy. Hot isothermal compression experiments were performed on Gleeble-3500 thermo-mechanical testing machine in the temperature range of 1153 to 1333 K within the strain rate range of 0.001 to 10 s-1. The deformation behavior of INCONEL 718 is analyzed and summarized by establishing the high temperature deformation constitutive equation. The calculated correlation coefficient ( R) and average absolute relative error ( AARE) underline the precision of proposed constitutive model.

  1. Thermo-mechanical and experimental analysis of double pass line heating

    NASA Astrophysics Data System (ADS)

    Biswas, Pankaj; Mandal, N. R.; Sha, O. P.; Mahapatra, M. M.

    2011-06-01

    The present investigation deals with process analysis of oxy-acetylene flame assisted double pass line heating for varying plate thickness. oxy-acetylene flame as the heat source for multi pass line heating to achieve 3-D bending of plates with varying thicknesses was studied. The oxy-acetylene flame was modeled as the moving heat source in the FEM analysis. The transient thermal histories were predicted taking into account the temperature dependent thermo-mechanical properties. A comparative study between single pass and double pass line heating residual deformation was also carried out. The temperature distribution and residual deformations predicted by the numerical model developed in the present work compared fairly well with those of the experimental ones.

  2. Low Cycle and Thermo-Mechanical Fatigue of Friction Welded Dissimilar Superalloys Joint

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Motoki; Sano, Atsushi; Tran, Tra Hung; Okazaki, Masakazu; Sekihara, Masaru

    The high temperature strengths of the dissimilar friction welded superalloys joint between the cast polycrystalline Mar-M247 and the forged IN718 alloys have been investigated under low cycle and thermo-mechanical fatigue loadings, in comparison with those of the base metals. The experiments showed that the lives of the dissimilar joints were significantly influenced by the test conditions and loading modes. Not only the lives themselves but also the failure positions and mechanisms were sensitive to the loading mode. The fracture behaviors depending on the loading modes and test conditions were discussed, based on the macroscopic elastic follow-up mechanism and the microstructural inhomogeneity in the friction weld joint.

  3. Rheological properties of refined wheat - millet flour based dough under thermo-mechanical stress.

    PubMed

    Chakraborty, Subir K; Tiwari, Anu; Mishra, Atishay; Singh, Alok

    2015-05-01

    Designed experiments were conducted to study the rheological properties of baking dough prepared from different refined wheat flour (RWF) - barnyard millet blends with varying amount of water (WA), salt and sugar. Dough was subjected to thermo-mechanical stress in Mixolab, in which rheological properties were recorded in terms of five different torques. Second order polynomial models were developed using response surface methodology (RSM) to understand the effect of input variables (WA, barnyard millet, salt and sugar; all expressed as per cent of base flour) on torques recorded by Mixolab. Optimum values of input variables were obtained with constraints based on torque values which represented the qualities of acceptable bread dough. The models predicted that a dough with 57, 26, 1.8 and 3.3% of water, barnyard millet, salt and sugar, respectively, can be used for bread baking purposes.

  4. New nano-particle-strengthened ferritic/martensitic steels by conventional thermo-mechanical treatment

    NASA Astrophysics Data System (ADS)

    Klueh, R. L.; Hashimoto, N.; Maziasz, P. J.

    2007-08-01

    For increased fusion power plant efficiency, steels for operation at 650 °C and higher are sought. Based on the science of precipitate strengthening, a thermo-mechanical treatment (TMT) was developed that increased the strength from room temperature to 700 °C of commercial nitrogen-containing steels and new steels designed for the TMT. At 700 °C increases in yield stress of 80 and 200% were observed for a commercial steel and a new steel, respectively, compared to commercial normalized-and-tempered steels. Creep-rupture strength was similarly improved. Depending on the TMT, precipitates were up to eight-times smaller at a number density four orders of magnitude greater than those in a conventionally heat treated steel of similar composition.

  5. Influence of Carbon Nano Tubes on the Thermo-Mechanical Properties of Unsaturated Polyester Nanocomposite

    NASA Astrophysics Data System (ADS)

    Moshiul Alam, A. K. M.; Beg, M. D. H.; Mohd Yunus, Rosli

    2015-04-01

    To date nano fillers are renowned reinforcing agent for polymer materials. In this work, unsaturated polyester (UPR) nanocomposites were fabricated by 0.1, 0.3 and 0.5 wt% multi walled carbon nanotubes (MWCNTs) through solution dispersion and casting method. The influence of MWCNT content was investigated by thermo-mechanical properties. Dispersion of nanotubes was observed by fracture morphology. The strength of nanocomposites rose with raising the CNT content. Moreover, DSC thermograms of nanocomposites represent noticeable improvement of glass transition temperature (Tg), melting temperature (Tm) and enthalpy (ΔHm). Micro-crystallinity of nanocomposites increased with increasing the CNT content. Moreover, the stiffness increased with increasing the CNT content.

  6. An efficient, three dimensional, fully-coupled hydro-thermo- mechanical simulator

    SciTech Connect

    Kelkar, S.; Zyvoloski, G.

    1990-01-01

    Hydro-thermo-mechanical effects in fractured rocks are important in many oilfield processes. Modeling these effects is made difficult by the fact that the governing equations are nonlinear and coupled, and the problems to be solved are three dimensional. In this paper the authors describe a numerical code developed for this purpose. The code is finite element based to allow for complicated geometries, and the time differencing is implicit, allowing for large time steps. The use of state-of-the-art equation solvers has resulted in a practical code. An example is presented to demonstrate the effects of matrix expansion, due to pore pressure and heating, on fracture opening due to fluid injection, and induced stress changes at a distant well bore. 19 refs., 9 figs., 3 tabs.

  7. Development of Semantic Description for Multiscale Models of Thermo-Mechanical Treatment of Metal Alloys

    NASA Astrophysics Data System (ADS)

    Macioł, Piotr; Regulski, Krzysztof

    2016-08-01

    We present a process of semantic meta-model development for data management in an adaptable multiscale modeling framework. The main problems in ontology design are discussed, and a solution achieved as a result of the research is presented. The main concepts concerning the application and data management background for multiscale modeling were derived from the AM3 approach—object-oriented Agile multiscale modeling methodology. The ontological description of multiscale models enables validation of semantic correctness of data interchange between submodels. We also present a possibility of using the ontological model as a supervisor in conjunction with a multiscale model controller and a knowledge base system. Multiscale modeling formal ontology (MMFO), designed for describing multiscale models' data and structures, is presented. A need for applying meta-ontology in the MMFO development process is discussed. Examples of MMFO application in describing thermo-mechanical treatment of metal alloys are discussed. Present and future applications of MMFO are described.

  8. Multiscale Simulation of Thermo-Mechanical Processes in Irradiated Fission-Reactor Materials

    SciTech Connect

    Louis Rene Corrales

    2010-11-01

    This research characterized, by atomic level molecular dynamics (MD) simulations, the early stage aggregation of the fission product xenon in a model uranium oxide nuclear fuel matrix that contributes to the long term bubble formation mechanisms that compromise the efficiency and lifetime of nuclear fuels. These atomic level computer simulations disclosed a previously unknown pre-coarsening phenomenon in which the clustering of xenon is driven by vacancy diffusion. These key findings are to be included in higher level simulations of nuclear fuel thermo-mechanical processes that model irradiation effects within nuclear fuels. Previous multiscale models did not include these early time pre-coarsened clusters that occur in the nanosecond regime and therefore will lead to a better understanding of bubble formation in nuclear fuels.

  9. Thermo-mechanical concepts applied to modeling liquid propellant rocket engine stability

    NASA Astrophysics Data System (ADS)

    Kassoy, David R.; Norris, Adam

    2016-11-01

    The response of a gas to transient, spatially distributed energy addition can be quantified mathematically using thermo-mechanical concepts available in the literature. The modeling demonstrates that the ratio of the energy addition time scale to the acoustic time scale of the affected volume, and the quantity of energy added to that volume during the former determine the whether the responses to heating can be described as occurring at nearly constant volume, fully compressible or nearly constant pressure. Each of these categories is characterized by significantly different mechanical responses. Application to idealized configurations of liquid propellant rocket engines provides an opportunity to identify physical conditions compatible with gasdynamic disturbances that are sources of engine instability. Air Force Office of Scientific Research.

  10. An Approximate Dissipation Function for Large Strain Rubber Thermo-Mechanical Analyses

    NASA Technical Reports Server (NTRS)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2003-01-01

    Mechanically induced viscoelastic dissipation is difficult to compute. When the constitutive model is defined by history integrals, the formula for dissipation is a double convolution integral. Since double convolution integrals are difficult to approximate, coupled thermo-mechanical analyses of highly viscous rubber-like materials cannot be made with most commercial finite element software. In this study, we present a method to approximate the dissipation for history integral constitutive models that represent Maxwell-like materials without approximating the double convolution integral. The method requires that the total stress can be separated into elastic and viscous components, and that the relaxation form of the constitutive law is defined with a Prony series. Numerical data is provided to demonstrate the limitations of this approximate method for determining dissipation. Rubber cylinders with imbedded steel disks and with an imbedded steel ball are dynamically loaded, and the nonuniform heating within the cylinders is computed.

  11. Thermo-mechanical Response and Onset of Instability of Thin Film Layer Due to Thermal Loading

    NASA Astrophysics Data System (ADS)

    Imatani, Shoji; Thammakornbunjut, Ek-u.

    2010-09-01

    A new simulation technique is proposed in order to evaluate the thermo-mechanical response of thin film layer attached or jointed to substrate. A thermo-elasto-plastic finite element analysis is carried out on a jointed system while only the film layer is picked up and a deformation analysis is in parallel implemented with reference to the data obtained in the analysis on the jointed body. This approach enables us to capture the mechanical stiffness of the thin film layer considered as an independent body. The effects of crystal morphology of substrate and the surface roughness of interface are discussed on the inhomogeneity force evolution, the out-of-plane deformation and the buckling of thin film layer.

  12. Third-order thermo-mechanical properties for packs of Platonic solids using statistical micromechanics

    PubMed Central

    Gillman, A.; Amadio, G.; Matouš, K.; Jackson, T. L.

    2015-01-01

    Obtaining an accurate higher order statistical description of heterogeneous materials and using this information to predict effective material behaviour with high fidelity has remained an outstanding problem for many years. In a recent letter, Gillman & Matouš (2014 Phys. Lett. A 378, 3070–3073. ()) accurately evaluated the three-point microstructural parameter that arises in third-order theories and predicted with high accuracy the effective thermal conductivity of highly packed material systems. Expanding this work here, we predict for the first time effective thermo-mechanical properties of granular Platonic solid packs using third-order statistical micromechanics. Systems of impenetrable and penetrable spheres are considered to verify adaptive methods for computing n-point probability functions directly from three-dimensional microstructures, and excellent agreement is shown with simulation. Moreover, a significant shape effect is discovered for the effective thermal conductivity of highly packed composites, whereas a moderate shape effect is exhibited for the elastic constants. PMID:27547103

  13. A thermo-mechanically coupled finite strain model considering inelastic heat generation

    NASA Astrophysics Data System (ADS)

    Dunić, Vladimir; Busarac, Nenad; Slavković, Vukašin; Rosić, Bojana; Niekamp, Rainer; Matthies, Hermann; Slavković, Radovan; Živković, Miroslav

    2016-07-01

    The procedure for reuse of finite element method (FEM) programs for heat transfer and structure analysis to solve advanced thermo-mechanical problems is presented as powerful algorithm applicable for coupling of other physical fields (magnetic, fluid flow, etc.). In this case, nonlinear Block-Gauss-Seidel partitioned algorithm strongly couples the heat transfer and structural FEM programs by a component-based software engineering. Component template library provides possibility to exchange the data between the components which solve the corresponding subproblems. The structural component evaluates the dissipative energy induced by inelastic strain. The heat transfer component computes the temperature change due to the dissipation. The convergence is guaranteed by posing the global convergence criterion on the previously locally converged coupled variables. This enables reuse of software and allows the numerical simulation of thermo-sensitive problems.

  14. Evaluation of Thermal and Thermo-mechanical Behavior of Full-scale Energy Foundations

    NASA Astrophysics Data System (ADS)

    Murphy, Kyle D.

    This study focuses on the thermo-mechanical and thermal behavior of full-scale energy foundations installed as part of two buildings recently constructed in Colorado. The soil stratigraphy at each of the sites differed, but both foundations were expected to function as primarily end-bearing elements with a tip socketed into rock. The heat exchanger configurations were also different amongst the foundations at both sites, permitting evaluation of the role of heat exchange. A common thread for both energy foundation case histories was the monitoring of the temperature and axial strain within the foundations during heat exchange operations. The first case study involves an evaluation of the long-term thermo-mechanical response of two full-scale energy foundations installed at the new Denver Housing Authority (DHA) Senior Living Facility at 1099 Osage St. in Denver, Colorado. Due to the construction schedule for this project, the thermal properties of the foundations and surrounding subsurface could not be assessed using thermal response tests. However, instrumentation was incorporated into the foundations to assess their long-term heat exchange response as well as the thermo-mechanical strains, stresses, and displacements that occurred during construction and operation of the ground-source heat pump system. The temperature changes within the foundations during heating and cooling operations over a period of approximately 600 days ranged from 9 to 32 °C, respectively. The thermal axial stresses in the foundations were calculated from the measured strains, and ranged from 3.1 MPa during heating to --1.0 MPa during cooling. These values are within reasonable limits for reinforced concrete structures. The maximum thermal axial stress was observed near the toe of both foundations, which is consistent with trends expected for end-bearing toe boundary conditions. The greatest thermal axial strains were observed near the top of the foundations (upward expansion during

  15. Thermo-mechanical modelling of salt caverns due to fluctuating loading conditions.

    NASA Astrophysics Data System (ADS)

    Böttcher, N.

    2015-12-01

    This work summarizes the development and application of a numerical model for the thermo-mechanical behaviour of salt caverns during cyclic gas storage. Artificial salt caverns are used for short term energy storage, such as power-to-gas or compressed air energy storage. Those applications are characterized by highly fluctuating operation pressures due to the unsteady power levels of power plants based on renewable energy. Compression and expansion of the storage gases during loading and unloading stages lead to rapidly changing temperatures in the host rock of the caverns. This affects the material behaviour of the host rock within a zone that extends several meters into the rock mass adjacent to the cavern wall, and induces thermo-mechanical stresses and alters the creep response.The proposed model features the thermodynamic behaviour of the storage medium, conductive heat transport in the host rock, as well as temperature dependent material properties of rock salt using different thermo-viscoplastic material models. The utilized constitutive models are well known and state-of-the-art in various salt mechanics applications. The model has been implemented into the open-source software platform OpenGeoSys. Thermal and mechanical processes are solved using a finite element approach, coupled via a staggered coupling scheme. The simulation results allow the conclusion, that the cavern convergence rate (and thus the efficiency of the cavern) is highly influenced by the loading cycle frequency and the resulting gas temperatures. The model therefore allows to analyse the influence of operation modes on the cavern host rock or on neighbouring facilities.

  16. Enhancement of the electrochemical behaviour and biological performance of Ti-25Ta-5Zr alloy by thermo-mechanical processing.

    PubMed

    Cimpean, Anisoara; Vasilescu, Ecaterina; Drob, Paula; Cinca, Ion; Vasilescu, Cora; Anastasescu, Mihai; Mitran, Valentina; Drob, Silviu Iulian

    2014-05-01

    A new Ti-25Ta-5Zr alloy based only on non-toxic and non-allergic elements was elaborated in as-cast and thermo-mechanical processed, recrystallized states (XRD and SEM) in order to be used as candidate material for implant applications. Its long-term interactions with Ringer-Brown and Ringer solutions of different pH values and its cytocompatibility were determined. The thermo-mechanically processed alloy has nobler electrochemical behaviour than as-cast alloy due to finer microstructure obtained after the applied treatment. Corrosion and ion release rates presented the lowest values for the treated alloy. Nyquist and Bode plots displayed higher impedance values and phase angles for the processed alloy, denoting a more protective passive film. SEM micrographs revealed depositions from solutions that contain calcium, phosphorous and oxygen ions (EDX analysis), namely calcium phosphate. An electric equivalent circuit with two time constants was modelled. Cell culture experiments with MC3T3-E1 pre-osteoblasts demonstrated that thermo-mechanically processed Ti-25Ta-5Zr alloy supports a better cell adhesion and spreading, and enhanced cell proliferation. Altogether, these data indicate that thermo-mechanical treatment endows the alloy with improved anticorrosion and biological performances.

  17. Magmatism vs mushmatism: 2D thermo-mechanical modelling of crustal mush processes

    NASA Astrophysics Data System (ADS)

    Roele, K.; Morgan, J. V.; Jackson, M.

    2015-12-01

    The concept of 'mushmatism'- that a magma chamber resides in a crystalline state for the majority of its life, has been suggested as a plausible mechanism for observed crustal melt evolution. It is proposed that as melt is generated, its composition evolves as it rises buoyantly, reacting chemically with the surrounding crystal mush at progressively lower temperatures. It is therefore possible to explain formation of granitic melts and observed mafic-felsic layering in the crust using mush processes. It has previously been assumed that a high influx rate of molten material is required for large volumes of crustal melt to be produced. This has been modelled in the past with repetitive sill intrusion at unrealistically high rates (>3x107 m3a-1) to cause a large enough thermal perturbation of the geotherm to sustain eruptible melt in the shallow crust. However, these models are purely thermal and neglect the effects of melt segregation and mush processes on longevity of melt volumes in the crust. We have developed an axisymmetric thermo-mechanical model that includes mass transport described by coupled matrix compaction and buoyant melt segregation during repeated sill intrusion. Results are consistent with thermal models in that they demonstrate dominance of crystalline mush processes in the transient magma chamber at low-to-moderate intrusion rates. However, addition of buoyant segregation leads to formation of discrete high melt fraction layers as melt ascends through the emplacement zone. This causes a decoupling in location of maximum temperature and melt fraction not observed by purely thermal models. Our results therefore have significant implications for current methods of interpretation of geophysical data, in particular, calculating melt volumes and determining the depth of the magma chamber. In addition, transient reservoirs are produced at lower emplacement rates by the thermo-mechanical model because accumulated magma is evolved and able to remain liquid

  18. Thermo-mechanical modelling of cyclic gas storage applications in salt caverns

    NASA Astrophysics Data System (ADS)

    Böttcher, Norbert; Watanabe, Norihiro; Görke, Uwe-Jens; Kolditz, Olaf; Nagel, Thomas

    2016-04-01

    Due to the growing importance of renewable energy sources it becomes more and more necessary to investigate energy storage potentials. One major way to store energy is the power-to-gas concept. Excessive electrical energy can be used either to produce hydrogen or methane by electrolysis or methanation or to compress air, respectively. Those produced gases can then be stored in artificial salt caverns, which are constructed in large salt formations by solution mining. In combination with renewable energy sources, the power-to-gas concept is subjected to fluctuations. Compression and expansion of the storage gases lead to temperature differences within the salt rock. The variations can advance several metres into the host rock, influencing its material behaviour, inducing thermal stresses and altering the creep response. To investigate the temperature influence on the cavern capacity, we have developed a numerical model to simulate the thermo-mechanical behaviour of salt caverns during cyclic gas storage. The model considers the thermodynamic behaviour of the stored gases as well as the heat transport and the temperature dependent material properties of the host rock. Therefore, we utilized well-known constitutive thermo-visco-plastic material models, implemented into the open source-scientific software OpenGeoSys. Both thermal and mechanical processes are solved using a finite element approach, connected via a staggered coupling scheme. The model allows the assessment of the structural safety as well as the convergence of the salt caverns.

  19. Thermo-mechanical Fatigue Failure of Thermal Barrier Coated Superalloy Specimen

    NASA Astrophysics Data System (ADS)

    Subramanian, Rajivgandhi; Mori, Yuzuru; Yamagishi, Satoshi; Okazaki, Masakazu

    2015-09-01

    Failure behavior of thermal barrier coated (TBC) Ni-based superalloy specimens were studied from the aspect of the effect of bond coat material behavior on low cycle fatigue (LCF) and thermo-mechanical fatigue (TMF) at various temperatures and under various loading conditions. Initially, monotonic tensile tests were carried out on a MCrAlY alloy bond coat material in the temperature range of 298 K to 1273 K (25 °C to 1000 °C). Special attention was paid to understand the ductile to brittle transition temperature (DBTT). Next, LCF and TMF tests were carried out on the thermal barrier coated Ni-based alloy IN738 specimen. After these tests, the specimens were sectioned to understand their failure mechanisms on the basis of DBTT of the bond coat material. Experimental results demonstrated that the LCF and TMF lives of the TBC specimen were closely related to the DBTT of the bond coat material, and also the TMF lives were different from those of LCF tests. It has also been observed that the crack density in the bond coat in the TBC specimen was significantly dependent on the test conditions. More importantly, not only the number of cracks but also the crack penetration probability into substrate were shown to be sensitive to the DBTT.

  20. A numerical model of hydro-thermo-mechanical coupling in a fractured rock mass

    SciTech Connect

    Bower, Kathleen Marie

    1996-06-01

    Coupled hydro-thermo-mechanical codes with the ability to model fractured materials are used for predicting groundwater flow behavior in fractured aquifers containing thermal sources. The potential applications of such a code include the analysis of groundwater behavior within a geothermal reservoir. The capability of modeling hydro-thermo systems with a dual porosity, fracture flow model has been previously developed in the finite element code, FEHM. FEHM has been modified to include stress coupling with the dual porosity feature. FEHM has been further developed to implicitly couple the dependence of fracture hydraulic conductivity on effective stress within two dimensional, saturated aquifers containing fracture systems. The cubic law for flow between parallel plates was used to model fracture permeability. The Bartin-Bandis relationship was used to determine the fracture aperture within the cubic law. The code used a Newton Raphson iteration to implicitly solve for six unknowns at each node. Results from a model of heat flow from a reservoir to the moving fluid in a single fracture compared well with analytic results. Results of a model showing the increase in fracture flow due to a single fracture opening under fluid pressure compared well with analytic results. A hot dry rock, geothermal reservoir was modeled with realistic time steps indicating that the modified FEHM code does successfully model coupled flow problems with no convergence problems.

  1. Thermo-mechanical properties of W/Mo markers coatings deposited on bulk W

    NASA Astrophysics Data System (ADS)

    Grigore, E.; Ruset, C.; Gherendi, M.; Chioibasu, D.; Hakola, A.; contributors, JET

    2016-02-01

    In the present paper marker structures consisting of W/Mo layers were deposited on bulk W samples by using a modified CMSII method. This technology, compared to standard CMSII, prevents the formation of nano-pore structures at interfaces. The thicknesses of the markers were in the range 20-35 μm to balance the requirements associated with the wall erosion in ITER and thermo-mechanical performances. The coatings structure and composition were evaluated by glow discharge optical emission spectrometry (GDOES), and energy dispersive x-ray spectroscopy measurements (EDX). The adhesion of the coatings to the substrate has been assessed by scratch test method. In order to evaluate their effectiveness as potential markers for fusion applications, the marker coatings have been tested in an electron beam facility at a temperature of 1000 °C and a power density of about 3 MW m-2. A number of 300 pulses with duration of 420 s (35 testing hours) were applied on the marker coated samples.

  2. Time Evolution of Thermo-Mechanically and Chemically Coupled Magma Chambers

    NASA Astrophysics Data System (ADS)

    Ozimek, C.; Karlstrom, L.; Erickson, B. A.

    2015-12-01

    Complexity in the volcanic eruption cycle reflects time variation both of magma inputs to the crustal plumbing system and of crustal melt storage zones (magma chambers). These data include timing and volumes of eruptions, as well as erupted compositions. Thus models must take into account the coupled nature of physical attributes. Here we combine a thermo-mechanical model for magma chamber growth and pressurization with a chemical model for evolving chamber compositions, in the limit of rapid mixing, to study controls on eruption cycles and compositions through time. We solve for the mechanical evolution of a 1D magma chamber containing melt, crystals and bubbles, in a thermally evolving and viscoelastic crust. This pressure and temperature evolution constrains the input values of a chemical box model (Lee et al., 2013) that accounts for recharge, eruption, assimilation and fractional crystallization (REAFC) within the chamber. We plan to study the influence of melt supply, input composition, and chamber depth eruptive fluxes and compositions. Ultimately we will explore multiple chambers coupled by elastic-walled dikes. We expect that this framework will facilitate self-consistent inversion of long-term eruptive histories in terms of magma transport physics. Lee, C.-T. A., Lee, T.-C., Wu, C.-T., 2013. Modeling the compositional evolution of recharging, evacuating, and fractionating (REFC) magma chambers: Implications for differentiationof arc magmas. Geochemica Cosmochimica Acta, http://dx.doi.org/10.1016/j.gca.2013.08.009.

  3. FEA Based Tool Life Quantity Estimation of Hot Forging Dies Under Cyclic Thermo-Mechanical Loads

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Bouguecha, A.; Schäfer, F.; Hadifi, T.

    2011-01-01

    Hot forging dies are exposed during service to a combination of cyclic thermo-mechanical, tribological and chemical loads. Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most frequent causes of failure. In order to extend the tool life, the finite element analysis (FEA) may serve as a means for process design and process optimisation. So far the FEA based estimation of the production cycles until initial cracking is limited as tool material behaviour due to repeated loading is not captured with the required accuracy. Material models which are able to account for cyclic effects are not verified for the fatigue life predictions of forging dies. Furthermore fatigue properties from strain controlled fatigue tests of relevant hot work steels are to date not available to allow for a close-to-reality fatigue life prediction. Two industrial forging processes, where clear fatigue crack initiation has been observed are considered for a fatigue analysis. For this purpose the relevant tool components are modelled with elasto-plastic material behaviour. The predicted sites, where crack initiation occurs, agree with the ones observed on the real die component.

  4. Optimized design of thermo-mechanically loaded non-uniform bars by using a variational method

    NASA Astrophysics Data System (ADS)

    Nayak, P.; Saha, K. N.

    2016-08-01

    The present paper evaluates the axial strain and stress of a thermo-mechanically loaded non-uniform bar by using a numerical method based on a variational principle. The solutions are obtained up to the elastic limit of the material based on the assumptions that material properties are independent of temperature variation and plane cross-sections remain plane maintaining axisymmetry. This approximation is carried out by Galerkin's principle, using a linear combination of sets of orthogonal co-ordinate functions which satisfy prescribed boundary conditions. The solution algorithm is implemented with the help of MATLAB® computational simulation software. Some numerical results of thermoelastic field are presented and discussed for different bar materials such as mild steel, copper, aluminium alloy 6061 (Al alloy 6061), aluminium alloy 7075 (Al alloy 7075) and diamond. The effect of geometry parameters like aspect ratio, slenderness ratio and the type of taperness is investigated and the relevant results are obtained in dimensional form. The term bar used in this paper is in generic sense and hence the formulation is applicable for all one dimensional elements, e.g., rods, pipes, truss members, etc.

  5. Grain boundary engineering in a thermo-mechanically processed Nb-stabilized austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Yunquera, A.; Jorge-Badiola, D.; Gutiérrez, I.; Iza-Mendia, A.

    2015-04-01

    Three different thermo-mechanical strategies—annealing, strain recrystallization and strain annealing—were applied to a Nb-stabilized 304H austenitic stainless steel in order to study their effects on grain boundary character distribution (GBCD). An Electron Backscatter Diffraction (EBSD) analysis revealed specific combinations of cold reduction-temperature-time that favor annealing twinning. A uniform increase in microstructural size and special boundaries (particularly for Σ3, Σ9 and Σ27 boundaries) was achieved under strain annealing conditions (low cold reductions) and long times at high temperatures (≥ 990°C). These conditions provide a high fraction of special boundaries (about 80%), which replace the random grain boundary network and thus optimize the GBCD. The profuse presence of Σ3n boundaries is attributed to the geometric interaction of twin-related variants during grain boundary migration. In addition to all this, precipitation takes place at the temperature range where optimum GBCD is achieved. The significance of precipitation in the different strategies was also tackled.

  6. Modeling the Coupled Chemo-Thermo-Mechanical Behavior of Amorphous Polymer Networks.

    SciTech Connect

    Zimmerman, Jonathan A.; Nguyen, Thao D.; Xiao, Rui

    2015-02-01

    Amorphous polymers exhibit a rich landscape of time-dependent behavior including viscoelasticity, structural relaxation, and viscoplasticity. These time-dependent mechanisms can be exploited to achieve shape-memory behavior, which allows the material to store a programmed deformed shape indefinitely and to recover entirely the undeformed shape in response to specific environmental stimulus. The shape-memory performance of amorphous polymers depends on the coordination of multiple physical mechanisms, and considerable opportunities exist to tailor the polymer structure and shape-memory programming procedure to achieve the desired performance. The goal of this project was to use a combination of theoretical, numerical and experimental methods to investigate the effect of shape memory programming, thermo-mechanical properties, and physical and environmental aging on the shape memory performance. Physical and environmental aging occurs during storage and through exposure to solvents, such as water, and can significantly alter the viscoelastic behavior and shape memory behavior of amorphous polymers. This project – executed primarily by Professor Thao Nguyen and Graduate Student Rui Xiao at Johns Hopkins University in support of a DOE/NNSA Presidential Early Career Award in Science and Engineering (PECASE) – developed a theoretical framework for chemothermo- mechanical behavior of amorphous polymers to model the effects of physical aging and solvent-induced environmental factors on their thermoviscoelastic behavior.

  7. Multiscale Approach to the Physics of Ion-Beam Therapy:. Thermo-Mechanical Damage

    NASA Astrophysics Data System (ADS)

    Solov'yov, A. V.; Yakubovich, A. V.; Surdutovich, E.

    2012-01-01

    We present a brief overview of the multiscale approach towards the understanding of processes responsible for the radiation damage caused by energetic ions. This knowledge is important because it can be utilized in the ion-beam cancer therapy, which is one of the most advanced modern techniques to cure certain types of cancer. The central element of the multiscale approach is the theoretical evaluation and quantification of DNA damage within cell environment. We consider different pathways of DNA damage and focus on the the illustration of the thermo-mechanical effects caused by the propagation of ions through the biological environment and in particular on the possibility of the creation of the shock waves in the vicinity of the ion tracks. We demonstrate that at the initial stages after ion's passage the shock wave is so strong that it can contribute to the DNA damage due to large pressure gradients developed at the distances of a few nanometers from the ionic tracks. This novel mechanism of the DNA damage provides an important contribution to the cumulative bio-damage caused by low-energy secondary electrons, holes and free radicals.

  8. Synthesis and thermo-mechanical characterization of bare and composite chitosan films

    NASA Astrophysics Data System (ADS)

    Blagg, Amanda

    In this present work, chitosan thin films were synthesized via two synthesis techniques: sol casting and spin coating. Subsequently, silver nanoparticles or carbon black particles were incorporated into the polymeric matrix at various loadings. Produced films were characterized by optical microscopy and profilometry to investigate the morphological properties of the films; Fourier transform infrared spectroscopy and X-ray diffraction to confirm the presence of chitosan in all films; and UV-vis to confirm the presence of the silver nanoparticles. In addition, thermal degradation and thermo mechanical analyses were conducted to establish the temperature range in which produced composites can be used. The average degradation temperature and the average glass transition temperature were determined to be 292±5 °C and 82±8 °C, respectively. Therefore these films may be used at temperatures up to 70 °C without any significant change in mechanical properties, and at temperatures up to 280 °C before experiencing degradation.

  9. A new method for modeling thermo-mechanical behaviors of polycrystalline aggregates

    NASA Astrophysics Data System (ADS)

    Tian, Xia; Cui, JunZhi; Li, BoWen

    2012-11-01

    We present in this paper a numerical algorithm that couples the atomistic and continuum models for the thermal-mechanical coupled problem of polycrystalline aggregates. The key point is that the conservation laws should be satisfied for both the atomistic and continuum models at the microscale. Compared with the traditional methods which construct the constitutive equations of the grain interiors and grain boundaries by continuum mechanics, our model calculates the continuum fluxes through molecular dynamics simulations, provided that the atomistic simulations are consistent with the local microstate of the system. For the grain interiors without defects, central schemes are available for solving the conservation laws and the constitutive parameters can be obtained via molecular dynamics simulations. For the grain boundary structures, the front tracking method is employed because the solutions of the conservation equations are discontinuous near the defects. Firstly, appropriate control volumes are chosen at both sides of the interface, then the finite volume method is applied to solve the continuum equations in each control volume. Fluxes near both sides of the interface are calculated via atomistic simulations. Therefore, all thermo-mechanical information can be obtained.

  10. Thermal stability and thermo-mechanical properties of magnetron sputtered Cr-Al-Y-N coatings

    SciTech Connect

    Rovere, Florian; Mayrhofer, Paul H.

    2008-01-15

    Cr{sub 1-x}Al{sub x}N coatings are promising candidates for advanced machining and high temperature applications due to their good mechanical and thermal properties. Recently the authors have shown that reactive magnetron sputtering using Cr-Al targets with Al/Cr ratios of 1.5 and Y contents of 0, 2, 4, and 8 at % results in the formation of stoichiometric (Cr{sub 1-x}Al{sub x}){sub 1-y}Y{sub y}N films with Al/Cr ratios of {approx}1.2 and YN mole fractions of 0%, 2%, 4%, and 8%, respectively. Here, the impact of Y on thermal stability, structural evolution, and thermo-mechanical properties is investigated in detail. Based on in situ stress measurements, thermal analyzing, x-ray diffraction, and transmission electron microscopy studies the authors conclude that Y effectively retards diffusional processes such as recovery, precipitation of hcp-AlN and fcc-YN, grain growth, and decomposition induced N{sub 2} release. Hence, the onset temperature of the latter shifts from {approx}1010 to 1125 deg. C and the hardness after annealing at T{sub a}=1100 deg. C increases from {approx}32 to 39 GPa with increasing YN mole fraction from 0% to 8%, respectively.

  11. Multidisciplinary approach to assess thermo-mechanical properties of the Asian lithosphere

    NASA Astrophysics Data System (ADS)

    Stolk, Ward; Kaban, Mikhail; Tesauro, Magdala; Beekman, Fred; Cloetingh, Sierd

    2013-04-01

    Assessing the thermo-mechanical properties of the lithospheric mantle is a complex business and still poses many problems. Seismic studies indicate large heterogeneities within the mantle lithosphere, but cannot discern between e.g. thermal and compositional effects. Similarly, gravity field analysis can constrain density heterogeneities, but is by its nature unable to distinguish between e.g. stacked density anomalies or lateral density anomalies. A joint analysis of both data types potentially leads to an improved insight in the mantle lithosphere, though the solution to the problem at hand remains non-unique and additional constraints are required. We have combined a high resolution tomography model with a recent global gravity field model to improve our knowledge of both the compositional and thermal aspects of the mantle lithosphere in the Asian continent. The preliminary results presented here will focus on the four major cratonic areas in Asia: the East European Platform, Siberia, Northeast China and India. These regions represent two distinct types of cratonic lithosphere (deep root and shallow root). Xenolith studies help us to further constrain the trade off between temperature and compositional effects.

  12. The Moho in extensional tectonic settings: Insights from thermo-mechanical models

    NASA Astrophysics Data System (ADS)

    Cloetingh, Sierd; Burov, Evgenii; Matenco, Liviu; Beekman, Fred; Roure, François; Ziegler, Peter A.

    2013-12-01

    The lithospheric memory is key for the interplay of lithospheric stresses and rheological structure of the extending lithosphere and for its later tectonic reactivation. Other important factors are the temporal and spatial migration of extension and the interplay of rifting and surface processes. The mode of extension and the duration of the rifting phase required to lead to continental break-up are to a large extent controlled by the interaction of the extending plate with slab dynamics. The finite strength of the lithosphere has an important effect on the formation of extensional basins. This applies both to the geometry of the basin shape as well as to the record of vertical motions during and after rifting. We demonstrate a strong connection between the bulk rheological properties of Europe's lithosphere and the evolution of some of Europe's main rifts and back-arc systems. The thermo-mechanical structure of the lithosphere has a major impact on continental break-up and associated basin migration processes, with direct relationships between rift duration and extension velocities, thermal evolution, and the role of mantle plumes. Compressional reactivation has important consequences for post-rift inversion, borderland uplift, and denudation, as illustrated by poly-phase deformation of extensional back-arc basins in the Black Sea and the Pannonian Basin region.

  13. Probabilistic Simulation of Combined Thermo-Mechanical Cyclic Fatigue in Composites

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2011-01-01

    A methodology to compute probabilistically-combined thermo-mechanical fatigue life of polymer matrix laminated composites has been developed and is demonstrated. Matrix degradation effects caused by long-term environmental exposure and mechanical/thermal cyclic loads are accounted for in the simulation process. A unified time-temperature-stress-dependent multifactor-interaction relationship developed at NASA Glenn Research Center has been used to model the degradation/aging of material properties due to cyclic loads. The fast probability-integration method is used to compute probabilistic distribution of response. Sensitivities of fatigue life reliability to uncertainties in the primitive random variables (e.g., constituent properties, fiber volume ratio, void volume ratio, ply thickness, etc.) computed and their significance in the reliability-based design for maximum life is discussed. The effect of variation in the thermal cyclic loads on the fatigue reliability for a (0/+/-45/90)s graphite/epoxy laminate with a ply thickness of 0.127 mm, with respect to impending failure modes has been studied. The results show that, at low mechanical-cyclic loads and low thermal-cyclic amplitudes, fatigue life for 0.999 reliability is most sensitive to matrix compressive strength, matrix modulus, thermal expansion coefficient, and ply thickness. Whereas at high mechanical-cyclic loads and high thermal-cyclic amplitudes, fatigue life at 0.999 reliability is more sensitive to the shear strength of matrix, longitudinal fiber modulus, matrix modulus, and ply thickness.

  14. Space Shuttle Orbiter Wing-Leading-Edge Panel Thermo-Mechanical Analysis for Entry Conditions

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Song, Kyongchan; Raju, Ivatury S.

    2010-01-01

    Linear elastic, thermo-mechanical stress analyses of the Space Shuttle Orbiter wing-leading-edge panels is presented for entry heating conditions. The wing-leading-edge panels are made from reinforced carbon-carbon and serve as a part of the overall thermal protection system. Three-dimensional finite element models are described for three configurations: integrated configuration, an independent single-panel configuration, and a local lower-apex joggle segment. Entry temperature conditions are imposed and the through-the-thickness response is examined. From the integrated model, it was concluded that individual panels can be analyzed independently since minimal interaction between adjacent components occurred. From the independent single-panel model, it was concluded that increased through-the-thickness stress levels developed all along the chord of a panel s slip-side joggle region, and hence isolated local joggle sections will exhibit the same trend. From the local joggle models, it was concluded that two-dimensional plane-strain models can be used to study the influence of subsurface defects along the slip-side joggle region of these panels.

  15. Probabilistic Simulation of Combined Thermo-Mechanical Cyclic Fatigue in Composites

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2010-01-01

    A methodology to compute probabilistically-combined thermo-mechanical fatigue life of polymer matrix laminated composites has been developed and is demonstrated. Matrix degradation effects caused by long-term environmental exposure and mechanical/thermal cyclic loads are accounted for in the simulation process. A unified time-temperature-stress-dependent multifactor-interaction relationship developed at NASA Glenn Research Center has been used to model the degradation/aging of material properties due to cyclic loads. The fast probability-integration method is used to compute probabilistic distribution of response. Sensitivities of fatigue life reliability to uncertainties in the primitive random variables (e.g., constituent properties, fiber volume ratio, void volume ratio, ply thickness, etc.) computed and their significance in the reliability-based design for maximum life is discussed. The effect of variation in the thermal cyclic loads on the fatigue reliability for a (0/+/-45/90)s graphite/epoxy laminate with a ply thickness of 0.127 mm, with respect to impending failure modes has been studied. The results show that, at low mechanical-cyclic loads and low thermal-cyclic amplitudes, fatigue life for 0.999 reliability is most sensitive to matrix compressive strength, matrix modulus, thermal expansion coefficient, and ply thickness. Whereas at high mechanical-cyclic loads and high thermal-cyclic amplitudes, fatigue life at 0.999 reliability is more sensitive to the shear strength of matrix, longitudinal fiber modulus, matrix modulus, and ply thickness.

  16. Thermo-mechanical toner transfer for high-quality digital image correlation speckle patterns

    NASA Astrophysics Data System (ADS)

    Mazzoleni, Paolo; Zappa, Emanuele; Matta, Fabio; Sutton, Michael A.

    2015-12-01

    The accuracy and spatial resolution of full-field deformation measurements performed through digital image correlation are greatly affected by the frequency content of the speckle pattern, which can be effectively controlled using particles with well-defined and consistent shape, size and spacing. This paper introduces a novel toner-transfer technique to impress a well-defined and repeatable speckle pattern on plane and curved surfaces of metallic and cement composite specimens. The speckle pattern is numerically designed, printed on paper using a standard laser printer, and transferred onto the measurement surface via a thermo-mechanical process. The tuning procedure to compensate for the difference between designed and toner-transferred actual speckle size is presented. Based on this evidence, the applicability of the technique is discussed with respect to surface material, dimensions and geometry. Proof of concept of the proposed toner-transfer technique is then demonstrated for the case of a quenched and partitioned welded steel plate subjected to uniaxial tensile loading, and for an aluminum plate exposed to temperatures up to 70% of the melting point of aluminum and past the melting point of typical printer toner powder.

  17. Effect of thermo-mechanical stress during quench on Nb3Sn cable performance

    SciTech Connect

    Linda Imbasciati et al.

    2002-12-09

    Several high field magnets using Nb{sub 3}Sn superconductor are under development for future particle accelerators. The high levels of stored energy in these magnets can cause high peak temperatures during a quench. The thermomechanical stress generated in the winding during the fast temperature rise can result in a permanent damage of the brittle Nb{sub 3}Sn. Although there are several studies of the critical current degradation of Nb{sub 3}Sn strands due to strain, little is known about how to apply the strain limitations to define a maximum acceptable temperature in the coils during a quench. Therefore, an experimental program was launched, aimed at improving the understanding of the effect of thermo-mechanical stress in coils made from brittle Nb{sub 3}Sn. A first experiment, reported here, was performed on cables. The experimental results were compared to analytical and finite element models. The next step in the experimental program will be to repeat similar measurements in small racetrack coils and later in full size magnets.

  18. Rheological, thermo-mechanical, and baking properties of wheat-millet flour blends.

    PubMed

    Aprodu, Iuliana; Banu, Iuliana

    2015-07-01

    Millet has long been known as a good source of fiber and antioxidants, but only lately started to be exploited by food scientists and food industry as a consequence of increased consumer awareness. In this study, doughs and breads were produced using millet flour in different ratios (10, 20, 30, 40, and 50%) to white, dark, and whole wheat flour. The flour blends were evaluated in terms of rheological and thermo-mechanical properties. Fundamental rheological measurements revealed that the viscosity of the flour formulations increases with wheat flour-extraction rate and decreases with the addition of millet flour. Doughs behavior during mixing, overmixing, pasting, and gelling was established using the Mixolab device. The results of this bread-making process simulation indicate that dough properties become critical for the flour blends with millet levels higher than 30%. The breads were evaluated for volume, texture, and crumb-grain characteristics. The baking test and sensory evaluation results indicated that substitution levels of up to 30% millet flour could be used in composite bread flour. High levels of millet flour (40 and 50%) negatively influenced the loaf volume, crumb texture, and taste.

  19. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    PubMed Central

    Xie, Weihua; Meng, Songhe; Jin, Hua; Du, Chong; Wang, Libin; Peng, Tao; Scarpa, Fabrizio; Xu, Chenghai

    2016-01-01

    This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs), which are equipped with chemical composition gratings sensors (CCGs). The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE) model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C. PMID:27754356

  20. Nano-precipitation Strengthened G91 by Thermo-mechanical Treatment Optimization

    NASA Astrophysics Data System (ADS)

    Vivas, J.; Celada-Casero, C.; San Martín, D.; Serrano, M.; Urones-Garrote, E.; Adeva, P.; Aranda, M. M.; Capdevila, C.

    2016-11-01

    The increase of thermal efficiency in power plants has been the main driving force to develop Ferritic/Martensitic steels for structural applications capable of operating at 923 K (650 °C) and higher. It has been clarified in previous works that nano-sized precipitates and its distribution are the key factors controlling the stability of the microstructure at high operating temperatures. Based on the science of precipitate strengthening, the aim of this work is to optimize the thermo-mechanical treatment in a commercial creep-resistant steel (G91) to achieve a microstructure where MX precipitates present a suitable size and distribution. The alternative processing route proposed here allows gaining an increase up to 40 pct in yield strength at 973 K (700 °C) compared to the commercial steel. The results of small punch test carried out at room temperature showed that the improvement in strength was obtained without loss of ductility. This fact was attributed to a finer and more homogeneous dispersion of MX precipitates in comparison to the commercial steel.

  1. Effect of atherosclerosis on thermo-mechanical properties of arterial wall and its repercussion on plaque instability.

    PubMed

    Guinea, G V; Atienza, J M; Fantidis, P; Rojo, F J; Ortega, A; Torres, M; Gonzalez, P; Elices, M L; Hayashi, K; Elices, M

    2009-03-06

    Data from the literature report febrile reactions prior to myocardial infarction in patients with normal coronary arteries and that coronary syndromes seem to be triggered by bacterial and viral infections, being fever the common symptom. The thermo-mechanical behavior of thoracic aortas of New Zealand White rabbits with different degrees of atherosclerosis was measured by means of pressure-diameter tests at different temperatures. Specific measurements of the thermal dilatation coefficient of atheroma plaques were performed by means of tensile tests. Results show a different thermo-mechanical behavior, the dilatation coefficient of atheroma plaque being at least twice that of the arterial wall. Temperature-induced mechanical stress at the plaque-vessel interface could be enough to promote plaque rupture. Therefore, increases of corporal temperature, either local or systemic, can play a role in increasing the risk of acute coronary syndromes and deserve a more comprehensive study.

  2. Thermo-mechanical Modelling of Pebble Beds in Fusion Blankets and its Implementation by a Return-Mapping Algorithm

    SciTech Connect

    Gan, Yixiang; Kamlah, Marc

    2008-07-01

    In this investigation, a thermo-mechanical model of pebble beds is adopted and developed based on experiments by Dr. Reimann at Forschungszentrum Karlsruhe (FZK). The framework of the present material model is composed of a non-linear elastic law, the Drucker-Prager-Cap theory, and a modified creep law. Furthermore, the volumetric inelastic strain dependent thermal conductivity of beryllium pebble beds is taken into account and full thermo-mechanical coupling is considered. Investigation showed that the Drucker-Prager-Cap model implemented in ABAQUS can not fulfill the requirements of both the prediction of large creep strains and the hardening behaviour caused by creep, which are of importance with respect to the application of pebble beds in fusion blankets. Therefore, UMAT (user defined material's mechanical behaviour) and UMATHT (user defined material's thermal behaviour) routines are used to re-implement the present thermo-mechanical model in ABAQUS. An elastic predictor radial return mapping algorithm is used to solve the non-associated plasticity iteratively, and a proper tangent stiffness matrix is obtained for cost-efficiency in the calculation. An explicit creep mechanism is adopted for the prediction of time-dependent behaviour in order to represent large creep strains in high temperature. Finally, the thermo-mechanical interactions are implemented in a UMATHT routine for the coupled analysis. The oedometric compression tests and creep tests of pebble beds at different temperatures are simulated with the help of the present UMAT and UMATHT routines, and the comparison between the simulation and the experiments is made. (authors)

  3. A geometrical multi-scale numerical method for coupled hygro-thermo-mechanical problems in photovoltaic laminates.

    PubMed

    Lenarda, P; Paggi, M

    A comprehensive computational framework based on the finite element method for the simulation of coupled hygro-thermo-mechanical problems in photovoltaic laminates is herein proposed. While the thermo-mechanical problem takes place in the three-dimensional space of the laminate, moisture diffusion occurs in a two-dimensional domain represented by the polymeric layers and by the vertical channel cracks in the solar cells. Therefore, a geometrical multi-scale solution strategy is pursued by solving the partial differential equations governing heat transfer and thermo-elasticity in the three-dimensional space, and the partial differential equation for moisture diffusion in the two dimensional domains. By exploiting a staggered scheme, the thermo-mechanical problem is solved first via a fully implicit solution scheme in space and time, with a specific treatment of the polymeric layers as zero-thickness interfaces whose constitutive response is governed by a novel thermo-visco-elastic cohesive zone model based on fractional calculus. Temperature and relative displacements along the domains where moisture diffusion takes place are then projected to the finite element model of diffusion, coupled with the thermo-mechanical problem by the temperature and crack opening dependent diffusion coefficient. The application of the proposed method to photovoltaic modules pinpoints two important physical aspects: (i) moisture diffusion in humidity freeze tests with a temperature dependent diffusivity is a much slower process than in the case of a constant diffusion coefficient; (ii) channel cracks through Silicon solar cells significantly enhance moisture diffusion and electric degradation, as confirmed by experimental tests.

  4. Thermo-mechanical analysis of a user filter assembly for undulator/wiggler operations at the Advanced Photon Source

    SciTech Connect

    Nian, H.L.T.; Kuzay, T.M.; Collins, J.; Shu, D.; Benson, C.; Dejus, R.

    1996-12-31

    This paper reports a thermo-mechanical study of a beamline filter (user filter) for undulator/wiggler operations. It is deployed in conjunction with the current commissioning window assembly on the APS insertion device (ID) front ends. The beamline filter at the Advanced Photon Source (APS) will eventually be used in windowless operations also. Hence survival and reasonable life expectancy of the filters under intense insertion device (ID) heat flu are crucial to the beamline operations. To accommodate various user requirements, the filter is configured to be a multi-choice type and smart to allow only those filter combinations that will be safe to operate with a given ring current and beamline insertion device gap. However, this paper addresses only the thermo-mechanical analysis of individual filter integrity and safety in all combinations possible. The current filter design is configured to have four filter frames in a cascade with each frame holding five filters. This allows a potential 625 total filter combinations. Thermal analysis for all of these combinations becomes a mammoth task considering the desired choices for filter materials (pyrolitic graphite and metallic filters), filter thicknesses, undulator gaps, and the beam currents. The paper addresses how this difficult task has been reduced to a reasonable effort and computational level. Results from thermo-mechanical analyses of the filter combinations are presented both in tabular and graphical format.

  5. Predicting the Operating Behavior of Ceramic Filters from Thermo-Mechanical Ash Properties

    SciTech Connect

    Hemmer, G.; Kasper, G.

    2002-09-19

    Stable operation, in other words the achievement of a succession of uniform filtration cycles of reasonable length is a key issue in high-temperature gas filtration with ceramic media. Its importance has rather grown in recent years, as these media gain in acceptance due to their excellent particle retention capabilities. Ash properties have been known for some time to affect the maximum operating temperature of filters. However, softening and consequently ''stickiness'' of the ash particles generally depend on composition in a complex way. Simple and accurate prediction of critical temperature ranges from ash analysis--and even more so from coal analysis--is still difficult without practical and costly trials. In general, our understanding of what exactly happens during break-down of filtration stability is still rather crude and general. Early work was based on the concept that ash particles begin to soften and sinter near the melting temperatures of low-melting, often alkaline components. This softening coincides with a fairly abrupt increase of stickiness, that can be detected with powder mechanical methods in a Jenicke shear cell as first shown by Pilz (1996) and recently confirmed by others (Kamiya et al. 2001 and 2002, Kanaoka et al. 2001). However, recording {sigma}-{tau}-diagrams is very time consuming and not the only off-line method of analyzing or predicting changes in thermo-mechanical ash behavior. Pilz found that the increase in ash stickiness near melting was accompanied by shrinkage attributed to sintering. Recent work at the University of Karlsruhe has expanded the use of such thermo-analytical methods for predicting filtration behavior (Hemmer 2001). Demonstrating their effectiveness is one objective of this paper. Finally, our intent is to show that ash softening at near melting temperatures is apparently not the only phenomenon causing problems with filtration, although its impact is certainly the ''final catastrophe''. There are other

  6. A Study of Thermo-mechanically Processed High Stiffness NiTiCo Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Manjeri, R. M.; Norwich, D.; Sczerzenie, F.; Huang, X.; Long, M.; Ehrlinspiel, M.

    2016-03-01

    This work investigates a vacuum induction melted-vacuum arc re-melted (VIM-VAR) and thermo-mechanically processed ternary NiTiCo shape memory alloy. The NiTiCo ingot was hot processed to 6.35-mm-diameter coiled wire. The coiled wire was subsequently cold drawn to a final wire diameter of 0.53 mm, with interpass anneals. The wires were shape set at 450 °C for 3.5 min. After electropolishing, the wires were subjected to microstructural, thermal, and mechanical characterization studies. Microstructural analysis was performed by transmission electron microscope (TEM), thermal analyses by differential scanning calorimeter (DSC), and bend-free recovery and mechanical testing by uniaxial tensile testing. TEM did not reveal Ni-rich precipitates—either at the grain boundary or in the grain interior. Energy dispersive x-ray spectroscopy showed a uniform distribution of Ni, Ti, and Co in the sample. The DSC results on the shape set wire showed a single-step transformation between the austenite and the R-phase, in the forward and reverse directions. Cyclic tensile tests of the shape set wire, processed under optimum conditions, showed minimum residual strain and a stable upper plateau stress. Further, the fatigue behavior of NiTi and NiTiCo alloys was studied by rotating beam testing. The results showed that the fatigue properties of NiTiCo, under zero mean strain, are equivalent to that of binary NiTi in the high-cycle and medium-cycle regimes, taking into account the higher stiffness of NiTiCo. The above analyses helped in establishing the processing-structure-property correlation in a VIM-VAR-melted NiTiCo shape memory alloy.

  7. Thermo-mechanical buckling analysis of FGM plate using generalized plate theory

    NASA Astrophysics Data System (ADS)

    Sharma, Kanishk; Kumar, Dinesh; Gite, Anil

    2016-05-01

    This paper investigates the thermo-mechanical buckling behavior of simply-supported FGM plate under the framework of generalized plate theory (GPT), which includes classical plate theory (CPT), first order shear deformation theory (FSDT) and higher order shear deformation theory (HSDT) as special cases. The governing equations for FGM plate under thermal and mechanical loading conditions are derived from the principle of virtual displacements and Navier-type solution is assumed for simply supported boundary condition. The efficiency and applicability of presented methodology is illustrated by considering various examples of thermal and mechanical buckling of FGM plates. The closed form solutions in the form of critical thermal and mechanical buckling loads, predicted by CPT, FSDT and HSDT are compared for different side-to-thickness of FGM plate. Subsequently, the effect of material gradation profile on critical buckling parameters is examined by evaluating the buckling response for a range of power law indexes. The effect of geometrical parameters on mechanical buckling of FGM plate under uni-axial and bi-axial loading conditions are also illustrated by calculating the critical load for various values of slenderness ratios. Furthermore a comparative analysis of critical thermal buckling loads of FGM plate for different temperature profiles is also presented. It is identified that all plate theories predicted approximately same critical buckling loads and critical buckling temperatures for thin FGM plate, however for thick FGM plates, CPT overestimates the critical buckling parameters. Moreover the critical buckling loads and critical buckling temperatures of FGM plate are found to be significantly lower than the corresponding homogenous isotropic ceramic plate (n=0).

  8. Seismo-thermo-mechanical modeling of mature and immature transform faults

    NASA Astrophysics Data System (ADS)

    Preuss, Simon; Gerya, Taras; van Dinther, Ylona

    2016-04-01

    Transform faults (TF) are subdivided into continental and oceanic ones due to their markedly different tectonic position, structure, surface expression, dynamics and seismicity. Both continental and oceanic TFs are zones of rheological weakness, which is a pre-requisite for their existence and long-term stability. Compared to subduction zones, TFs are typically characterized by smaller earthquake magnitudes as both their potential seismogenic width and length are reduced. However, a few very large magnitude (Mw>8) strike-slip events were documented, which are presumably related to the generation of new transform boundaries and/or sudden reactivation of pre-existing fossil structures. In particular, the 11 April 2012 Sumatra Mw 8.6 earthquake is challenging the general concept that such high magnitude events only occur at megathrusts. Hence, the processes of TF nucleation, propagation and their direct relation to the seismic cycle and long-term deformation at both oceanic and continental transforms needs to be investigated jointly to overcome the restricted direct observations in time and space. To gain fundamental understanding of involved physical processes the numerical seismo-thermo-mechanical (STM) modeling approach, validated in a subduction zone setting (Van Dinther et al. 2013), will be adapted for TFs. A simple 2D plane view model geometry using visco-elasto-plastic material behavior will be adopted. We will study and compare seismicity patterns and evolution in two end member TF setups, each with strain-dependent and rate-dependent brittle-plastic weakening processes: (1) A single weak and mature transform fault separating two strong plates (e.g., in between oceanic ridges) and (2) A nucleating or evolving (continental) TF system with disconnected predefined faults within a plate subjected to simple shear deformation (e.g., San Andreas Fault system). The modeling of TFs provides a first tool to establish the STM model approach for transform faults in a

  9. The long-term seismic cycle in collisional margins: insights from Seismo-Thermo-Mechanical models

    NASA Astrophysics Data System (ADS)

    Dal Zilio, L.; van Dinther, Y.; Gerya, T.

    2015-12-01

    The April 25, 2015, Mw 7.8 Gorkha earthquake is the largest one in the Nepal Himalaya since 1934. Since the foreland part of it is densely populated, these events represent a considerable seismic hazard. The restricted direct observations in time and space in combination with tectonic and rheological complexities, however, pose a difficult problem for both seismic hazard assessment and modeling efforts. In this study we for the first time simulate cycles of spontaneous earthquake-like ruptures on non a-priori defined faults within a generic continental collision zone. We use the Seismo-Thermo-Mechanical (STM) numerical modeling approach, which is based on a continuum, viscoelastoplastic code I2ELVIS and is validated for seismic cycle applications against a laboratory model and natural observations (van Dinther et al., 2013a, b). The 2-D model setup consists of two continental plates separated by an oceanic plate, in which the incipient subduction phase is followed by continent-continent collision. In different collisional stages, we evaluate a non-associative Drucker-Prager plasticity yield criterion with pressure dependent yield strength and a strongly rate-dependent friction formulation. Our results show physically consistent emergence of complex rupture paths, both on- and off-main frontal thrust. Assuming different physical properties of tectonic nappes, we find that ruptures propagate following rheological or tectonic discontinuities. Our findings suggest that the interseismic coupling of the main-thrust affects the seismic cycle of the entire orogenic belt. While thrust-faulting events mainly occur on the main frontal thrust, normal-faulting events spread throughout the orogenic belt as a consequence of gravitational extension. Results from an event detection algorithm shows events in the deeper portions of the orogenic belt, both within the oceanic slab and near the bottom of the wedge where material is squeezed between stiff lithospheric mantle portions.

  10. The role of thermo-mechanical feedback in the generation of shear zones in the lithosphere

    NASA Astrophysics Data System (ADS)

    Duretz, Thibault; Schmalholz, Stefan M.; Podladchikov, Yuri Y.

    2014-05-01

    The collision between continental plates results in the development of orogenic belts. Ongoing collision is responsible for the localisation of deformation and the development of shear zones. The presence of shear zones is well documented within orogens and their importance for the exhumation of high-grade (HG) metamorphic rocks is well accepted; their role in the formation of HG units is however debated. State of the art geodynamic modelling of continental collision is often used to model the genesis and exhumation of HG rocks. Nevertheless, it is a common approach to model collision by predefining shear zones and/or by employing constitutive models that can introduce mesh dependency. Mesh size dependency leads to difficult comparison between physical models and natural data since pressure and temperature cannot be accurately computed within the modelled shear zones. In this contribution, we employ thermo-mechanical modelling to study the formation of shear zones in the lithosphere. Our approach takes into account the coupling between momentum and energy balance by including viscous dissipation and temperature/stress dependant viscosity. We show that this methodology allows for the spontaneous development of shear zones around a cylindrical weak heterogeneity. Systematic simulations showed that this approach produces mesh-insensitive results. The modelled shear zones are hence characterised by a finite-width, which is independent on the numerical mesh resolution. Additional test were performed to constrain the physical parameters that control shear band thicknesses, the results highlight the role of thermal transport properties rather than the initial heterogeneity dimensions. Moreover, we demonstrate that these results can be achieved by using two different numerical methods, which are both popular methods in the geodynamic modelling community (Lagrangian finite elements and Eulerian-Lagrangian finite differences). Such models may therefore be reliably used to

  11. Slab breakoff: Insights from 3D thermo-mechanical analogue modelling experiments

    NASA Astrophysics Data System (ADS)

    Boutelier, D.; Cruden, A. R.

    2017-01-01

    The detachment or breakoff of subducted lithosphere is investigated using scaled three-dimensional thermo-mechanical analogue experiments in which forces are measured and deformation is monitored using high-speed particle imaging velocimetry (PIV). The experiments demonstrate that the convergence rate in a subduction zone determine if and when slab detachment occurs. Slow subduction experiments (with scaled convergence rates ∼1 cm yr-1) have lower Peclet numbers and are characterized by lower tensile strength subducted lithosphere, causing detachment to occur when the downward pull force exerted by a relatively short subducted slab is relatively low. Therefore when continental collision is preceded by slow oceanic subduction, the hot and weak subducted lithosphere need not be very long or extremely negatively buoyant to cause detachment. Under such conditions, detachment may occur sooner after the onset of continental subduction than previously predicted. In contrast, if collision is preceded by rapid subduction (∼10 cm yr-1), breakoff will be delayed and occur only when the convergence rate has slowed sufficiently to thermally weaken the slab and cause its eventual failure. The analogue experiments further confirm that slab detachment occurs diachronously as it propagates along the plate boundary. Stereoscopic PIV reveals a characteristic strain pattern that accompanies the detachment. Horizontal contraction and subsidence (with scaled values up to 1200 m) in the trench and forearc area precedes the passage of the detachment, and is followed by horizontal extension and uplift (up to 900 m). High-frequency monitoring captures rapid propagation of the detachment along the plate boundary at scaled rates of up to 100 cm yr-1. However this rate is not constant and interaction between the slab and lower mantle or opening of a backarc basin in the upper plate can reduce or stop slab breakoff propagation altogether.

  12. 3-D thermo-mechanical modeling of plume-induced subduction initiation

    NASA Astrophysics Data System (ADS)

    Baes, M.; Gerya, T.; Sobolev, S. V.

    2016-11-01

    Here, we study the 3-D subduction initiation process induced by the interaction between a hot thermo-chemical mantle plume and oceanic lithosphere using thermo-mechanical viscoplastic finite difference marker-in-cell models. Our numerical modeling results show that self-sustaining subduction is induced by plume-lithosphere interaction when the plume is sufficiently buoyant, the oceanic lithosphere is sufficiently old and the plate is weak enough to allow the buoyant plume to pass through it. Subduction initiation occurs following penetration of the lithosphere by the hot plume and the downward displacement of broken, nearly circular segments of lithosphere (proto-slabs) as a result of partially molten plume rocks overriding the proto-slabs. Our experiments show four different deformation regimes in response to plume-lithosphere interaction: a) self-sustaining subduction initiation, in which subduction becomes self-sustaining; b) frozen subduction initiation, in which subduction stops at shallow depths; c) slab break-off, in which the subducting circular slab breaks off soon after formation; and d) plume underplating, in which the plume does not pass through the lithosphere and instead spreads beneath it (i.e., failed subduction initiation). These regimes depend on several parameters, such as the size, composition, and temperature of the plume, the brittle/plastic strength and age of the oceanic lithosphere, and the presence/absence of lithospheric heterogeneities. The results show that subduction initiates and becomes self-sustaining when the lithosphere is older than 10 Myr and the non-dimensional ratio of the plume buoyancy force and lithospheric strength above the plume is higher than approximately 2. The outcomes of our numerical experiments are applicable for subduction initiation in the modern and Precambrian Earth and for the origin of plume-related corona structures on Venus.

  13. Thermo-mechanically coupled subduction with a free surface using ASPECT

    NASA Astrophysics Data System (ADS)

    Fraters, Menno; Glerum, Anne; Thieulot, Cedric; Spakman, Wim

    2014-05-01

    ASPECT (Kronbichler et al., 2012), short for Advanced Solver for Problems in Earth's ConvecTion, is a new Finite Element code which was originally designed for thermally driven (mantle) convection and is built on state of the art numerical methods (adaptive mesh refinement, linear and nonlinear solver, stabilization of transport dominated processes and a high scalability on multiple processors). Here we present an application of ASPECT to modeling of fully thermo-mechanically coupled subduction. Our subduction model contains three different compositions: a crustal composition on top of both the subducting slab and the overriding plate, a mantle composition and a sticky air composition, which allows for simulating a free surface for modeling topography build-up. We implemented a visco-plastic rheology using frictional plasticity and a composite viscosity defined by diffusion and dislocation creep. The lithospheric mantle has the same composition as the mantle but has a higher viscosity because of a lower temperature. The temperature field is implemented in ASPECT as follows: a linear temperature gradient for the lithosphere and an adiabatic geotherm for the sublithospheric mantle. Initial slab temperature is defined using the analytical solution of McKenzie (1970). The plates can be pushed from the sides of the model, and it is possible to define an additional independent mantle in/out flow through the boundaries. We will show a preliminary set of models, highlighting the codes capabilities, such as the Adaptive Mesh Refinement, topography development and the influence of mantle flow on the subduction evolution. Kronbichler, M., Heister, T., and Bangerth, W. (2012), High accuracy mantle convection simulation through modern numerical methods, Geophysical Journal International,191, 12-29, doi:10.1111/j.1365-246X.2012.05609. McKenzie, D.P. (1970), Temperature and potential temperature beneath island arcs, Teconophysics, 10, 357-366, doi:10.1016/0040-1951(70)90115-0.

  14. Plume-lithosphere interactions near a passive continental margin: a thermo-mechanical modelling study

    NASA Astrophysics Data System (ADS)

    François, Thomas; Cloetingh, Sierd; Burov, Evgueni; Matenco, Liviu

    2015-04-01

    Plume head-lithosphere (PLI) interactions have important consequences both for tectonic and mineralogical evolution of the lithosphere and are often considered to be an important factor of continental break-up. Nevertheless, the interaction between plume and post break-up tectonics (i.e. evolution of passive margins) remain unclear. The passive margins represent important geometrical, thermal and rheological barriers that interact with the plume head material during its emplacement below the lithosphere. For example on the Scandinavia's North Atlantic passive margin the large Cenozoic uplift comprised uplift of basin margins as well as accelerated subsidence of basin centres adjacent to the uplifted landmasses while the compressional reactivation coincides with the postulated Iceland-plume events associated with massive magma emplacement. The goal of this study is to understand the role of the Iceland plume in the Cenozoic evolution of the Scandinavia's North Atlantic passive margin. To investigate the interactions between the plume and passive margin we use fully coupled thermo-mechanical 2D numerical code (Flamar v12). The model area is 700 km deep and 1500 km wide comprising rheologically realistic lithosphere and the entire upper mantle Our models have free upper surface boundary, surface erosion, account for the rheological stratification (upper crust, lower crust, lithospheric mantle and asthenosphere), brittle-elastic-ductile rheology, metamorphic phase changes (density and physical properties) and for the specific crustal and thermal structure of the Scandinavia's North Atlantic passive margin. We have tested several parameters including the lateral position of the plume, the rate of extension and the thermo-rheological profile of the continental lithosphere.

  15. The Moho in extensional tectonic settings: insights from thermo-mechanical models

    NASA Astrophysics Data System (ADS)

    Cloetingh, Sierd; Burov, Evgenii; Liviu, Matenco

    2013-04-01

    We review consequences for the crustal and lithospheric configuration of different models for the thermo-mechanical evolution of continental lithosphere in extensional tectonic settings. The lithospheric memory is key for the interplay of lithospheric stresses and rheological structure of the extending lithosphere and for its later tectonic reactivation. Other important factors are the temporal and spatial migration of extension and the interplay of rifting and surface processes. The mode of extension and the duration of the rifting phase required to lead to continental break-up is to a large extent controlled by the interaction of the extending plate with slab dynamics. We compare predictions from numerical models with observational constraints from a number of rifted back-arc basin settings and intraplate domains at large distance from convergent plate boundaries. We discuss the record of vertical motions during and after rifting in the context of stretching models developed to quantify rifted basin formation. The finite strength of the lithosphere has an important effect on the formation of extensional basins. This applies both to the geometry of the basin shape as well as to the record of vertical motions during and after rifting. We demonstrate a strong connection between the bulk rheological properties of Europe's lithosphere and the evolution of some of Europe's main rifts and back-arc system. The thermomechanical structure of the lithosphere has a major impact on continental breakup and associated basin migration processes, with direct relationships between rift duration and extension velocities, thermal evolution, and the role of mantle plumes. Compressional reactivation has important consequences for post-rift inversion, borderland uplift, and denudation, as illustrated by polyphase deformation of extensional back-arc basins in the Black Sea and the Pannonian Basin.

  16. Modeling of thermo-mechanical and irradiation behavior of mixed oxide fuel for sodium fast reactors

    NASA Astrophysics Data System (ADS)

    Karahan, Aydın; Buongiorno, Jacopo

    2010-01-01

    An engineering code to model the irradiation behavior of UO2-PuO2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named fuel engineering and structural analysis tool (FEAST-OXIDE). FEAST-OXIDE has several modules working in coupled form with an explicit numerical algorithm. These modules describe: (1) fission gas release and swelling, (2) fuel chemistry and restructuring, (3) temperature distribution, (4) fuel-clad chemical interaction and (5) fuel-clad mechanical analysis. Given the fuel pin geometry, composition and irradiation history, FEAST-OXIDE can analyze fuel and cladding thermo-mechanical behavior at both steady-state and design-basis transient scenarios. The code was written in FORTRAN-90 program language. The mechanical analysis module implements the LIFE algorithm. Fission gas release and swelling behavior is described by the OGRES and NEFIG models. However, the original OGRES model has been extended to include the effects of joint oxide gain (JOG) formation on fission gas release and swelling. A detailed fuel chemistry model has been included to describe the cesium radial migration and JOG formation, oxygen and plutonium radial distribution and the axial migration of cesium. The fuel restructuring model includes the effects of as-fabricated porosity migration, irradiation-induced fuel densification, grain growth, hot pressing and fuel cracking and relocation. Finally, a kinetics model is included to predict the clad wastage formation. FEAST-OXIDE predictions have been compared to the available FFTF, EBR-II and JOYO databases, as well as the LIFE-4 code predictions. The agreement was found to be satisfactory for steady-state and slow-ramp over-power accidents.

  17. Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation

    NASA Astrophysics Data System (ADS)

    L-Cancelos, R.; Varas, F.; Martín, E.; Viéitez, I.

    2016-03-01

    Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different mechanical properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the mechanical behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large deformations. The thermo-mechanical model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved.

  18. Simulation of Solid-State Weld Microstructures in Ti-17 via Thermal and Thermo- Mechanical Exposures

    NASA Astrophysics Data System (ADS)

    Orsborn, Jonathan

    Solid-state welding processes are very important to the advancement of aviation technology; since they enable the joining of dissimilar metals without the additional weight and bulk of fastening systems, the processes can create for stronger and lighter parts to increase payload and efficiency. However, since the processes are not equilibrium, not much is understood about what happens to the materials during the process. During a solid-state weld, the materials being welded are exposed to rapid heating rates, high maximum temperatures, large and varying amounts of deformation, short hold times at temperature, and fast cooling rates. Due to the dynamic nature of the process it is very hard to measure the strains and temperatures experienced by the materials. This work attempted to simulate the microstructures observed in solid-state welds of Ti-5Al-2Sn-2Zr-4Cr-4Mo, or Ti-17. If the microstructures could be replicated in a controlled and repeatable fashion, then perhaps the conditions of the welding process could be indirectly determined. The simulations were performed by rapidly heating Ti-17 specimens, holding them for a very short time, and rapidly cooling. Some of the samples were also subjected to deformation while at high temperatures. The microstructures resulting from the thermal and thermo-mechanical exposures were then compared with microstructures from an actual solid-state weld of Ti-17. It was determined that the presence of untransformed secondary alpha indicates the temperature did not exceed the beta transus of the alloy (˜900 °C), the presence of untransformed primary alpha indicates that the temperature did not exceed ˜1100 °C, homogenized beta grains indicate that the temperature did exceed 1100°C, and the presence of ghost alpha is indicative that the temperature likely exceeded ˜950 °C. These numbers are rough estimates, as time at temperature and heating rate both factor into the process, and shorter times at higher temperatures can

  19. Thermo-mechanically tunable Bragg grating filters on silicon-on-insulator rib waveguide bridges

    NASA Astrophysics Data System (ADS)

    Raum, Christopher R.

    This thesis explores the integration of an optical device within a micromechanical structure to enhance its performance and enable behaviour it would otherwise be incapable of. Thermo-mechanically tunable Bragg grating filters on silicon-on-insulator rib waveguide bridges have been designed, fabricated and characterised to demonstrate what happens when an optical device, and the actuator used to tune its optical response, are physically the same structure. The process flow developed to fabricate the device was a five mask process that included a bridge waveguide, integrated filter, and integrated heater. A surface micromachining technique was developed to release up to 4000 mum long, 5 mum thick waveguide bridges. The device has three distinct operating regimes: pre-buckle, buckle, and post-buckle. The pre-buckle experimental thermal sensitivity of the filter was 76 pm/°C and the theoretical sensitivity was 83 pm/°C. During the transient buckle regime, the Bragg filter wavelength was measured to shift 0.95 nm, and theorised to shift 0.55 nm. The post-buckle experimental thermal sensitivity of the filter was 88 pm/°C and the theoretical sensitivity was 99 pm/°C. The rib waveguide bridge was observed to possess a meta-stable regime between the pre- and post-buckle regimes. Before the critical buckle temperature could be attained, the bridge deflected 0.5 mum out-of-plane and remained static over a range of 7.5 °C, whereupon it deflected to its full 15.1 mum buckling mode height. This metastable deflection caused a Bragg wavelength shift of 0.39 nm. The thermal sensitivity of the Bragg filter wavelength in this meta-stable regime was 62 pm/°C. Rectangular cross-section beams did not produce this behaviour. Mechano-optical bi-stability was also observed. In this bi-stable regime there would be two possible Bragg wavelengths for a given temperature, depending on whether the device was in a forward or return path. The bi-stable regime occurred over a span of 15

  20. Experimental evidence of thermo-mechanical pressurization of faults during earthquakes

    NASA Astrophysics Data System (ADS)

    Violay, Marie; Di Toro, Giulio; Nielsen, Stefan; Spagnuolo, Elena; Burg, Jean-Pierre

    2015-04-01

    Earthquakes occur while fault strength decreases with increasing slip and slip rate. Thermo-mechanical pressurization of pore fluids induced by frictional heating during seismic slip is one of the possible mechanisms responsible for fault dynamic weakening. However, has not yet been observed in the laboratory. To investigate seismic slip in the presence of pore fluids, 26 friction experiments were conducted at room temperature on hollow cylinders (50/30 mm external/internal diameter) of Etna basalt (1) under room-dry conditions or immersed in water under either (2) drained conditions (constant pore pressure, preventing fluid pressurization), and (3) undrained conditions (constant pore volume). Experiments were performed by spinning two basalt cylinders with the rotary shear machine (SHIVA, INGV Rome) at target slip rates (V) of 3 m/s, displacements (δ) from 4 m to 6 m, normal stress (σn) ranging from 15 to 35 MPa and initial pore fluid pressure (Pf) of 5 MPa.The experimental data are compared with those obtained from carbonate-bearing rocks (Carrara marble). In all the experiments, the coefficient of friction μ decayed exponentially from a peak value (μp = 0.55 ∓ 0.07) at about the initiation of slip towards a steady-state value μss of 0.1 under room-dry conditions, 0.1 under drained conditions and 0.08 under undrained conditions. The shear stress decay was about 75 percent over the first 5 cm of slip, independently of the ambient conditions. However, at a given σneff, δ and V, steady state shear stress was 20 percent lower under undrained than under drained and room dry conditions. Moreover, Pf under undrained conditions increased with displacement following a power law. Conversely, Pf and σn did not vary under drained conditions. After all experiments, a continuous, 100-200 µm thick, layer of glass (Scanning Electron Microscope investigation) separated the rock cylinders, irrespective of the ambient and hydraulic conditions. In summary, the mechanical

  1. A Modified Wilson Cycle Scenario Based on Thermo-Mechanical Model

    NASA Astrophysics Data System (ADS)

    Baes, M.; Sobolev, S. V.

    2014-12-01

    The major problem of classical Wilson Cycle concept is the suggested conversion of the passive continental margin to the active subduction zone. Previous modeling studies assumed either unusually thick felsic continental crust at the margin (over 40 km) or unusually low lithospheric thickness (less than 70 km) to simulate this process. Here we propose a new triggering factor in subduction initiation process that is mantle suction force. Based on this proposal we suggest a modification of Wilson Cycle concept. Sometime after opening and extension of oceanic basin, continental passive margin moves over the slab remnants of the former active subduction zones in deep mantle. Such slab remnants or deep slabs of neighboring active subduction zones produce a suction mantle flow introducing additional compression at the passive margin. It results in the initiation of a new subduction zone, hence starting the closing phase of Wilson Cycle. In this scenario the weakness of continental crust near the passive margin which is inherited from the rifting phase and horizontal push force induced from far-field topographic gradient within the continent facilitate and speed up subduction initiation process. Our thermo-mechanical modeling shows that after a few tens of million years a shear zone may indeed develop along the passive margin that has typical two-layered 35 km thick continental crust and thermal lithosphere thicker than 100 km if there is a broad mantle down-welling flow below the margin. Soon after formation of this shear zone oceanic plate descends into mantle and subduction initiates. Subduction initiation occurs following over-thrusting of continental crust and retreating of future trench. In models without far-field topographic gradient within the continent subduction initiation requires weaker passive margin. Our results also indicate that subduction initiation depends on several parameters such as magnitude, domain size and location of suction mantle flow

  2. Updating the thermo-mechanical structure of the European lithosphere with subsurface temperature data

    NASA Astrophysics Data System (ADS)

    Limberger, Jon; van Wees, Jan-Diederik; Tesauro, Magdala; Bonté, Damien; Lipsey, Lindsay; Smit, Jeroen; Beekman, Fred; Cloetingh, Sierd

    2016-04-01

    As part of the EU FP7-funded Integrated Methods for Advanced Geothermal Exploration (IMAGE) project we developed a methodology to obtain an improved, physics-based thermal model of the European lithosphere. On the basis of geophysical data, the model is divided into a four layer geometry consisting of sediments, upper crust, lower crust and lithospheric mantle. The horizontal resolution is 10 by 10 km, while the vertical one is 250 m. The prior steady-state temperature distribution is calculated using vertical heat flow only. imposing as boundary conditions fixed temperatures at the surface and at the base of the lithosphere, respectively. Thermal properties, including radiogenic heat production and temperature- and pressure-dependent bulk thermal conductivity, are assigned on the base of the broad-scale lithological variation within the European crust. Further improvements of the thermal model, aiming at consistency between temperatures and heat flow observations and tectonic model predictions, are obtained by applying data assimilation. An Ensemble Kalman Filter (EnKF) is used to assimilate temperature data and improve the prior estimates of the thermal properties and the thermal field. One of the advantages of EnKF is that multiple model realisations yield uncertainties for both the thermal properties and the thermal field. Borehole temperature data are directly used for this procedure, when publically available. Regional thermal models - originally based on borehole data - are used for areas lacking any (public) borehole temperature data. A larger error is assigned to the temperature values derived from these models, in order to account for the higher uncertainty compared to direct-measured temperatures. The thermal model is also used together with compositional data to estimate the integrated strength of the lithosphere. The result is an updated thermo-mechanical model of the European lithosphere with estimated uncertainties for the thermal properties and the

  3. Insights from Thermo-Mechanically Coupled Modeling of High-Elevation Regions of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Sommers, A. N.; Rajaram, H.; Colgan, W. T.

    2014-12-01

    As observations become more plentiful through remote sensing and numerical models become increasingly sophisticated, a clear priority of the ice sheet modeling community is to compare model simulations with observations. Temperature and velocity conditions within the Greenland ice sheet and at the bed remain largely unknown with the exception of sparse borehole measurements, but much can be inferred from rigorous thermo-mechanically coupled modeling. Surface velocities on the Greenland ice sheet are well constrained, both from satellite imagery and field observations. We take advantage of the observed surface velocities at the PARCA stakes around the 2,000m elevation contour of the ice sheet as modeling targets that represent a broad range of flow characteristics in different regions. Prescribing ice geometry, we use a two-dimensional thermo-mechanically coupled model to calculate 'steady-state' velocity and temperature profiles throughout the depth of the ice along flowlines from the main divide to the 2,000m elevation contour. Vertical velocity calculations are based on first principles of mass conservation, accounting for convergence and divergence of the streamtube width, and the enthalpy-based temperature calculations also incorporate the effects of liquid water content in temperate ice through the flow law parameter. Numerous insights from our simulations are presented for different regions, such as the influence of variable geothermal heat flux, the treatment of basal boundary conditions, and appropriate enhancement factors based on the age of ice. Results indicate that areas of temperate bed do exist in the high-elevation interior in certain sections of Greenland. Also highlighted is the importance of including temperature calculations in ice sheet modeling, particularly in regions with a temperate bed. For example, on the west coast, computations assuming a constant temperature of -5°C result in a 41% underestimation of the surface velocity at the 2,000m

  4. Behavior of a Quasi-Isotropic Ply Metal Matrix Composite under Thermo-Mechanical and Isothermal Fatigue Loading

    DTIC Science & Technology

    1992-12-01

    Wiley & Sons, Inc., 1990. 2. Bates, Mark A. Thermo-Mechanical Fatigue. o f Fiber Reinforced Titanium Aluminide ComDosite. MS Thesis, AFIT/GAE/ENY/91S-1...Longitudinal interphase region modulus Ef, EflI Longitudinal fiber modulus Ei Constituent modulus of elasticity Em, EmlI Longitudinal matrix modulus...glass. One such candidate MMC likely to give positive results, and the target of this study, is SCS6/Ti-15-3, a titanium matrix that is reinforced with

  5. Design and thermo-mechanical analysis of a new NiTi shape memory alloy fixing clip.

    PubMed

    Nespoli, Adelaide; Dallolio, Villiam; Stortiero, Francesco; Besseghini, Stefano; Passaretti, Francesca; Villa, Elena

    2014-04-01

    In this work, a new NiTi shape memory alloy (SMA) bone fixator is proposed. Thanks to the shape memory effect, this device does not need any external tool for the fixation, as the anchorage is obtained only by the self-accommodation of the clip during the parent transformation. Calorimetry and thermo-mechanical tests were used to evaluate the phase transformation temperatures and to estimate the forces generated both during the fixing surgical procedure and after the surgical operation. An application on animal anatomical sample was also performed; an appropriate mechanical tightness as well as a good handiness has been found.

  6. The Thermo-Mechanical Problem of Internal and Edge Cracks in Multi-Layered Woven GFRP Laminates at Cryogenic Temperatures

    SciTech Connect

    Takeda, T.; Shindo, Y.; Narita, F.

    2004-06-28

    This paper presents the thermo-mechanical response of multi-layered G-11 woven glass/epoxy laminates with internal and/or edge cracks under tensile loading at cryogenic temperatures obtained from a two-dimensional finite element analysis. A condition of generalized plane strain is assumed to exist in the composite. Cracks are considered to occur in the transverse fiber bundles and extend through the entire thickness of the fiber bundles. The finite element model accounts for the temperature-dependent constituent properties. A detailed examination of the Young's modulus and stress distributions near the crack tip is carried out which provides insight into material behavior at cryogenic temperatures.

  7. Power subsystem automation study

    NASA Technical Reports Server (NTRS)

    Tietz, J. C.; Sewy, D.; Pickering, C.; Sauers, R.

    1984-01-01

    The purpose of the phase 2 of the power subsystem automation study was to demonstrate the feasibility of using computer software to manage an aspect of the electrical power subsystem on a space station. The state of the art in expert systems software was investigated in this study. This effort resulted in the demonstration of prototype expert system software for managing one aspect of a simulated space station power subsystem.

  8. Nanocomposites of polymers with layered inorganic nanofillers: Antimicrobial activity, thermo-mechanical properties, morphology, and dispersion

    NASA Astrophysics Data System (ADS)

    Songtipya, Ponusa

    's characteristics to the thermo-mechanical properties of their nanocomposites was systematically explored. The appropriate compatibilizer, based on HDPE-g-MA, was identified from achieving the best mechanical performance, i.e., maximizing the tensile modulus improvement without sacrificing the polymer ductility, which was found to be achieved where the smallest crystallinity change occured. It was revealed that lower-than-the matrix molecular weight HDPE-g-MA better enhanced the tensile properties across three HDPEs, compared to that of high viscosity HDPE-g-MA, while the flexural properties were not markedly affected by this parameter, but rather were mostly determined by the amount of clay nanofiller. Finally, polymer/layered double hydroxide (LDH, positively-charged layered clays, also termed as 'anionic' clays referring to their anion exchange capacity) were characterized as potential fillers for a variety of polymer matrices. The main focus in this part of the research was on the morphology and dispersion of the LDH as it related to their composition and their organic modification in relation to the nature of various polymers. Exemplary polymer matrices that span the range from non-polar to polar interactions---including Polypropylene (PP), polyethylenes (PE, and PE-copolymers), polymethyl-methacrylate (PMMA), polystyrene (PS)---were explored. It was observed that the LDH composition, organic modification, and polymer types were the parameters which controlled the LDH structure and dispersion, albeit in a rather involved fashion.

  9. Microstructure Evolution of a Platinum-Modified Nickel-Aluminide Coating During Thermal and Thermo-mechanical Fatigue

    NASA Astrophysics Data System (ADS)

    Sallot, Pierre; Maurel, Vincent; Rémy, Luc; N'Guyen, Franck; Longuet, Arnaud

    2015-10-01

    The microstructure evolution of a platinum-modified nickel-aluminide coating on single-crystal nickel-based superalloy was investigated for various thermal cycling and thermo-mechanical fatigue (TMF) conditions in air for a long-term exposure. An increase in roughness and in β→γ' transformation rate depends similarly on maximum temperature, holding time at maximum temperature and applied stress. Moreover, the evolution of the interdiffusion zone (IDZ) is analyzed by making the distinction between two layers, according to the major phases observed within these layers, namely β-(Ni,Pt)Al and γ'-Ni3Al. This distinction highlighted that the respective thickness evolution of these two layers are sensitive to each parameter of TMF tests with similar increase in evolution rate when increasing time, temperature, as well as applied stress. The distinctive features of phase transformation are finally discussed together with localization of phase transformation and measured evolution of phase transformation within the external coating and β- and γ'-IDZ layer thicknesses under thermal and thermo-mechanical fatigue. This analysis leads to a conclusion that grain boundaries within the external coating as well as interfaces, between thermally grown oxide, external coating, and IDZ, respectively, play a major role in diffusion, phase transformation, and microstructure evolution of typical platinum-modified nickel-aluminide coating.

  10. Proof-of-concept switchable hydrophobic/hydrophilic patterned surfaces from thermo-mechanically tailored acrylate systems

    NASA Astrophysics Data System (ADS)

    Laursen, Christopher M.

    A novel, proof-of-concept, switchable hydrophobic/hydrophilic structured surface targeted to assist in antifouling of materials in aqueous environments was created through the development of a multi-tiered platform. The understructure consists of a thermo-mechanically tailored acrylate based polymer patterned in a pillared array, which was then overlaid with spatially tailored hydrophobic/hydrophilic surface chemistry treatments. Development focused on the synthesis of a ternary acrylate system displaying proper thermo-mechanical behavior in submerged conditions for the understructure, creation of a sufficient soft molding technique, and methods to chemically alter water-surface wetting interactions. The final acrylate based polymer constituents were chosen based on expected low-toxicity and the ability to be photopolymerized, while the final system displayed appropriate mechanical toughness, water absorption, and material stiffness over a select temperature window. This was important as alteration in wettability characteristics relied upon a stark transition in the polymeric materials stiffness within a narrow temperature range. The material qualitatively displayed a more hydrophobic state with the pillared surface structures erect, and a more hydrophilic state with the pillars bent over.

  11. Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

    NASA Astrophysics Data System (ADS)

    Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

    2016-05-01

    Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 K to 1173 K (700 °C to 900 °C), was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/and above 1073 K (800 °C). Relatively low volume fraction of M23C6 precipitates was observed after processing at 1073 K (800 °C). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine-grained heat-affected zone region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard "normalization and tempering" processes. The steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room temperature toughness. The above data are also analyzed based on existing theories of creep deformation based on dislocation climb mechanism.

  12. Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

    DOE PAGES

    Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

    2016-02-23

    Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment (TMT) process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 to 1173 K (700 to 900ºC) was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/andmore » above 1073 K (800 ºC). Relatively low volume fraction of M23C6 precipitates was observed after processing at 1073 K (800 ºC). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine grained heat affected zone (FGHAZ) region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard “normalization and tempering” processes. Lastly, the steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room-temperature toughness. The above data is also analysed based on existing theories of creep deformation based on dislocation climb mechanism.« less

  13. Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

    SciTech Connect

    Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

    2016-02-23

    Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment (TMT) process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 to 1173 K (700 to 900ºC) was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/and above 1073 K (800 ºC). Relatively low volume fraction of M23C6 precipitates was observed after processing at 1073 K (800 ºC). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine grained heat affected zone (FGHAZ) region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard “normalization and tempering” processes. Lastly, the steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room-temperature toughness. The above data is also analysed based on existing theories of creep deformation based on dislocation climb mechanism.

  14. Influence of fluid thermal sensitivity on the thermo-mechanical stability of the Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Thomas, D. G.; Sureshkumar, R.; Khomami, B.

    2003-11-01

    Recent theoretical [Al-Mubaiyedh et al., Phys. Fluids 11, 3217 (1999); J. Fluid Mech. 462, 111 (2002)] and experimental [White and Muller, Phys. Rev. Lett. 84, 5130 (2000); J. Fluid Mech. 462, 133 (2002)] studies have revealed that viscous heating causes significant destabilization of the Taylor-Couette flow of highly viscous and thermally sensitive fluids. In this work, the roles of thermal sensitivity of fluid properties and co-rotation on the thermo-mechanical stability of Taylor-Couette flow are investigated theoretically. In turn, our theoretical findings are compared with the recent experimental ones by White and Muller [Phys. Fluids 14, 3880 (2002)]. It is shown that a finite gap temperature is necessary to predict the time-dependent transitions observed in the experiments. A universal scaling between the critical Reynolds number and the Nahme number is obtained for intermediate values of Nahme number ranging from 0.01 to 1.0. Studies are also performed to determine the influence of co-rotation of the outer cylinder relative to the inner one on the thermo-mechanical stability. Overall, a very favorable comparison between theoretical and experimental results is obtained.

  15. On the Effects of Thermal History on the Development and Relaxation of Thermo-Mechanical Stress in Cryopreservation

    PubMed Central

    Eisenberg, David P.; Steif, Paul S.; Rabin, Yoed

    2014-01-01

    This study investigates the effects of the thermal protocol on the development and relaxation of thermo-mechanical stress in cryopreservation by means of glass formation, also known as vitrification. The cryopreserved medium is modeled as a homogeneous viscoelastic domain, constrained within either a stiff cylindrical container or a highly compliant bag. Annealing effects during the cooling phase of the cryopreservation protocol are analyzed. Results demonstrate that an intermediate temperature-hold period can significantly reduce the maximum tensile stress, thereby decreasing the potential for structural damage. It is also demonstrated that annealing at temperatures close to glass transition significantly weakens the dependency of thermo-mechanical stress on the cooling rate. Furthermore, a slower initial rewarming rate after cryogenic storage may drastically reduce the maximum tensile stress in the material, which supports previous experimental observations on the likelihood of fracture at this stage. This study discusses the dependency of the various stress components on the storage temperature. Finally, it is demonstrated that the stiffness of the container wall can affect the location of maximum stress, with implications on the development of cryopreservation protocols. PMID:25792762

  16. A self-consistent plasticity theory for modeling the thermo-mechanical properties of irradiated FCC metallic polycrystals

    NASA Astrophysics Data System (ADS)

    Xiao, Xiazi; Song, Dingkun; Xue, Jianming; Chu, Haijian; Duan, Huiling

    2015-05-01

    A self-consistent theoretical framework is developed to model the thermo-mechanical behaviors of irradiated face-centered cubic (FCC) polycrystalline metals at low to intermediate homologous temperatures. In this model, both irradiation and temperature effects are considered at the grain level with the assist of a tensorial plasticity crystal model, and the elastic-visocoplastic self-consistent method is applied for the scale transition from individual grains to macroscopic polycrystals. The proposed theory is applied to analyze the mechanical behaviors of irradiated FCC copper. It is found that: (1) the numerical results match well with experimental data, which includes the comparison of results for single crystals under the load in different directions, and for polycrystals with the influences of irradiation and temperature. Therefore, the feasibility and accuracy of the present model are well demonstrated. (2) The main irradiation effects including irradiation hardening, post-yield softening, strain-hardening coefficient (SHC) dropping and the non-zero stress offset are all captured by the proposed model. (3) The increase of temperature results in the decrease of yield strength and SHC. The former is attributed to the weakened dislocation-defect interaction, while the latter is due to the temperature-strengthened dynamic recovery of dislocations through the thermally activated mechanism. The present model may provide a theoretical guide to predict the thermo-mechanical behaviors of irradiated FCC metals for the selection of structural materials in nuclear equipment.

  17. Influence of Annealing Time and Thermo-Mechanical Cycling on Constrained Recovery Properties of a Cold-Worked NiTi Wire

    NASA Astrophysics Data System (ADS)

    Yan, Xiaojun; Ge, Yuli; Van Humbeeck, Jan

    2017-02-01

    In this work, the influence of parameters such as annealing time, pre-strain and thermo-mechanical cycling on recovery stresses of NiTi wires has been investigated by using a dynamic mechanical analyzer. The results show that the maximum recovery stress decreases with increasing annealing time and increases with increasing pre-strain except for 60-min annealed sample with 4% pre-strain, which has a higher recovery stress than 45-min annealed sample with the same pre-strain. The recovery stresses drastically increase during the first two thermo-mechanical cycles for all samples, regardless of annealing time. The observed changes of recovery stress could be attributed to different transformation temperatures and mechanical properties induced by different annealing times and/or thermo-mechanical cycling.

  18. IO SUBSYSTEM 1 BETA

    SciTech Connect

    Sjaardema, Greg

    2002-08-21

    "IO Subsystem Ver. 1.0 Beta" uses standard object-oriented principles to minimize dependencies between the underlying input or output database format and the client code (i.e., Sierra) using the io subsystem. The interface and priciples are simolar to the Facade pattern described in the "Design Patterns" book by Gamma, et.al. The software uses data authentication algorithms to ensure data input/output is consistent with model being defined. "IO Subsystem Ver. 1.0 Beta" is a database independent input/output library for finite element analysis, preprocessing, post processing, and translation programs.

  19. Regional-scale geomechanical impact assessment of underground coal gasification by coupled 3D thermo-mechanical modeling

    NASA Astrophysics Data System (ADS)

    Otto, Christopher; Kempka, Thomas; Kapusta, Krzysztof; Stańczyk, Krzysztof

    2016-04-01

    Underground coal gasification (UCG) has the potential to increase the world-wide coal reserves by utilization of coal deposits not mineable by conventional methods. The UCG process involves combusting coal in situ to produce a high-calorific synthesis gas, which can be applied for electricity generation or chemical feedstock production. Apart from its high economic potentials, UCG may induce site-specific environmental impacts such as fault reactivation, induced seismicity and ground subsidence, potentially inducing groundwater pollution. Changes overburden hydraulic conductivity resulting from thermo-mechanical effects may introduce migration pathways for UCG contaminants. Due to the financial efforts associated with UCG field trials, numerical modeling has been an important methodology to study coupled processes considering UCG performance. Almost all previous UCG studies applied 1D or 2D models for that purpose, that do not allow to predict the performance of a commercial-scale UCG operation. Considering our previous findings, demonstrating that far-field models can be run at a higher computational efficiency by using temperature-independent thermo-mechanical parameters, representative coupled simulations based on complex 3D regional-scale models were employed in the present study. For that purpose, a coupled thermo-mechanical 3D model has been developed to investigate the environmental impacts of UCG based on a regional-scale of the Polish Wieczorek mine located in the Upper Silesian Coal Basin. The model size is 10 km × 10 km × 5 km with ten dipping lithological layers, a double fault and 25 UCG reactors. Six different numerical simulation scenarios were investigated, considering the transpressive stress regime present in that part of the Upper Silesian Coal Basin. Our simulation results demonstrate that the minimum distance between the UCG reactors is about the six-fold of the coal seam thickness to avoid hydraulic communication between the single UCG

  20. Thermo-mechanical parametric studies of Fixed Mask 1 and Photon Shutter 2 for APS front ends

    SciTech Connect

    Nian, H.L.T.; Kuzay, T.M.; Sheng, I.C.A.

    1992-09-03

    Fixed Mask 1 (FM1) and Photon Shutter 2 (PS2) are two of the critical elements on the front end of the beamlines at the Advanced Photon Source (APS) now under construction at Argonne National Laboratory (ANL). FMl and PS2 use an enhanced heat transfer tube developed at ANL. Due to a high localized thermal gradient on these components, inclined geometry is used in their design to spread the footprint of the x-ray beam. Complete closed form solutions for steady state conditions have been developed for the analyses of the thermal and thermo-mechanical behavior of FMl and PS2. A modified Manson-Coffin fatigue relation is proposed to predict the predict the thermal fatigue. The maximum temperatures and maximum effective stresses have been parametrically studied. Fatigue-failure life predictions are presented for the FM1 and PS2 designs.

  1. Improvement of the thermo-mechanical position stability of the beam position monitor in the PLS-II

    NASA Astrophysics Data System (ADS)

    Ha, Taekyun; Hong, Mansu; Kwon, Hyuckchae; Han, Hongsik; Park, Chongdo

    2016-09-01

    In the storage ring of the Pohang Light Source-II (PLS-II), we reduced the mechanical displacement of the electron-beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The BPM pickup itself must be kept stable to sub-micrometer precision in order for a stable photon beam to be provided to beamlines because the orbit feedback system is programmed to make the electron beam pass through the center of the BPM. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by an unintended beam abort. We reduced this deformation by improving the vacuum chamber support and by enhancing the water cooling. We report a thermo-mechanical analysis and displacement measurements for the BPM pickups after improvements.

  2. Durability Prediction of Solid Oxide Fuel Cell Anode Material under Thermo-Mechanical and Fuel Gas Contaminants Effects

    SciTech Connect

    Iqbal, Gulfam; Guo, Hua; Kang , Bruce S.; Marina, Olga A.

    2011-01-10

    Solid Oxide Fuel Cells (SOFCs) operate under harsh environments, which cause deterioration of anode material properties and service life. In addition to electrochemical performance, structural integrity of the SOFC anode is essential for successful long-term operation. The SOFC anode is subjected to stresses at high temperature, thermal/redox cycles, and fuel gas contaminants effects during long-term operation. These mechanisms can alter the anode microstructure and affect its electrochemical and structural properties. In this research, anode material degradation mechanisms are briefly reviewed and an anode material durability model is developed and implemented in finite element analysis. The model takes into account thermo-mechanical and fuel gas contaminants degradation mechanisms for prediction of long-term structural integrity of the SOFC anode. The proposed model is validated experimentally using a NexTech ProbostatTM SOFC button cell test apparatus integrated with a Sagnac optical setup for simultaneously measuring electrochemical performance and in-situ anode surface deformation.

  3. Damage Pre-Cursors Based Assessment of Accrued Thermo-Mechanical Damage and Remaining Useful Life in Field Deployed Electronics

    NASA Astrophysics Data System (ADS)

    Lall, Pradeep; Harsha, Mahendra; Goebel, Kai; Jones, Jim

    Field deployed electronics may accrue damage due to environmental exposure and usage after finite period of service but may not often have any o-indicators of failure such as cracks or delamination. A method to interrogate the damage state of field deployed electronics in the pre-failure space may allow insight into the damage initiation, progression, and remaining useful life of the deployed system. Aging has been previously shown to effect the reliability and constitutive behavior of second-level leadfree interconnects. Prognostication of accrued damage and assessment of residual life can provide valuable insight into impending failure. In this paper, field deployed parts have been extracted and prognosticated for accrued damage and remaining useful life in an anticipated future deployment environment. A subset of the field deployed parts have been tested to failure in the anticipated field deployed environment to validate the assessment of remaining useful life. In addition, some parts have been subjected to additional known thermo-mechanical stresses and the incremental damage accrued validated with respect to the amount of additional damage imposed on the assemblies. The presented methodology uses leading indicators of failure based on micro-structural evolution of damage to identify accrued damage in electronic systems subjected to sequential stresses of thermal aging and thermal cycling. Damage equivalency methodologies have been developed to map damage accrued in thermal aging to the reduction in thermo-mechanical cyclic life based on damage proxies. The expected error with interrogation of system state and assessment of residual life has been quantified. Prognostic metrics including α-λmetric, sample standard deviation, mean square error, mean absolute percentage error, average bias, relative accuracy, and cumulative relative accuracy have been used to compare the performance of the damage proxies.

  4. Preprototype SAWD subsystem

    NASA Technical Reports Server (NTRS)

    Nalette, T. A.

    1984-01-01

    A regenerable, three man preprototype solid amine, water desorbed (SAWD) CO2 removal and concentation subsystem was designed, fabricated, and successfully acceptance tested by Hamilton Standard. The preprototype SAWD incorporates a single solid amine canister to perform the CO2 removal function, an accumulator to provide the CO2 storage and delivery function, and a microprocessor which automatically controls the subsystem sequential operation and performance. The SAWD subsystem was configured to have a CO2 removal and CO2 delivery capability at the rate of 0.12 kg/hr (0.264 lb/hr) over the relative humidity range of 35 to 70%. The controller was developed to provide fully automatic control over the relative humidity range via custom software that was generated specifically for the SAWD subsystem. The preprototype SAWD subsystem demonstrated a total of 281 hours (208) cycles of operation during ten acceptance tests that were conducted over the 3 to 70% relative humidity range. This operation was comprised of 178 hours (128 cycles) in the CO2 overboard mode and 103 hours (80 cycles) in the CO2 reduction mode. The average CO2 removal/delivery rate met or exceeded the design specification rate of 0.12 kg/hr (0.254 lb/hr) for all ten of the acceptance tests.

  5. Experimental investigations on the state of the friction-welded joint zone in steel hybrid components after process-relevant thermo-mechanical loadings

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Bouguecha, A.; Vucetic, M.; Peshekhodov, I.; Matthias, T.; Kolbasnikov, N.; Sokolov, S.; Ganin, S.

    2016-10-01

    As a part of the newly established Collaborative Research Center 1153 (SFB 1153) "Process chain for the manufacturing of hybrid high-performance components by tailored forming" at the Leibniz Universität Hannover, the Institute of Forming Technology and Machines (IFUM) examines the influence of thermo-mechanical stresses on the reduced Young's modulus as well as the hardness of hybrid (steel-steel compound) joined semi-finished products. Currently the expertise in the production of bulk metal formed parts is limited to mono-materials. For manufacturing parts of hybrid materials and also for the methods of the new process routes, practical experience has to be gained. The subproject C1 within the collaborative research center 1153 with the short title "Failure Prediction" deals with the question, if the hybrid semi-finished products fulfill the thermo-mechanical demands or if they fail at the joining zone (JZ) during forging. For this purpose, stresses similar to those in the process were imposed on hybrid semi-finished products by torsion tests by using the thermo-mechanical test system Gleeble 3800. Afterwards, the specimens were examined metallographically and by nanoindentations with the help of a TriboIndenter TI950. Thus, first knowledge on the behaviour of thermo-mechanical stresses on the reduced Young's modulus and the hardness of hybrid joined semi-finished parts was gained.

  6. HL-20 subsystem design

    NASA Astrophysics Data System (ADS)

    Stone, H. W.; MacConochie, I. O.

    1993-10-01

    The NASA Langley Research Center has been developing a lifting-body configuration called the HL-20 for potential application as a personnel launch system orbiter that will provide the crew changeout at the Space Station Freedom. The objectives have been to provide an alternate manned access to space with a more cost-effective, efficient, reliable, and safer system for the routine transportation of people to LEO. The detailed study of this concept includes the subsystem design, flight software sizing, and mass properties that are discussed in this paper. The goals were to develop a subsystem complement to maximize operational efficiency with minimum development costs while using current technology. Subsystem selection and trade studies showed that current technology components will provide the required performance and operational effectiveness. Many of the selected components have Shuttle flight histories or considerable development heritage from other programs that will help minimize development costs.

  7. HL-20 subsystem design

    NASA Technical Reports Server (NTRS)

    Stone, H. W.; Macconochie, I. O.

    1993-01-01

    The NASA Langley Research Center has been developing a lifting-body configuration called the HL-20 for potential application as a personnel launch system orbiter that will provide the crew changeout at the Space Station Freedom. The objectives have been to provide an alternate manned access to space with a more cost-effective, efficient, reliable, and safer system for the routine transportation of people to LEO. The detailed study of this concept includes the subsystem design, flight software sizing, and mass properties that are discussed in this paper. The goals were to develop a subsystem complement to maximize operational efficiency with minimum development costs while using current technology. Subsystem selection and trade studies showed that current technology components will provide the required performance and operational effectiveness. Many of the selected components have Shuttle flight histories or considerable development heritage from other programs that will help minimize development costs.

  8. Power subsystem automation study

    NASA Technical Reports Server (NTRS)

    Imamura, M. S.; Moser, R. L.; Veatch, M.

    1983-01-01

    Generic power-system elements and their potential faults are identified. Automation functions and their resulting benefits are defined and automation functions between power subsystem, central spacecraft computer, and ground flight-support personnel are partitioned. All automation activities were categorized as data handling, monitoring, routine control, fault handling, planning and operations, or anomaly handling. Incorporation of all these classes of tasks, except for anomaly handling, in power subsystem hardware and software was concluded to be mandatory to meet the design and operational requirements of the space station. The key drivers are long mission lifetime, modular growth, high-performance flexibility, a need to accommodate different electrical user-load equipment, onorbit assembly/maintenance/servicing, and potentially large number of power subsystem components. A significant effort in algorithm development and validation is essential in meeting the 1987 technology readiness date for the space station.

  9. Topological subsystem codes

    SciTech Connect

    Bombin, H.

    2010-03-15

    We introduce a family of two-dimensional (2D) topological subsystem quantum error-correcting codes. The gauge group is generated by two-local Pauli operators, so that two-local measurements are enough to recover the error syndrome. We study the computational power of code deformation in these codes and show that boundaries cannot be introduced in the usual way. In addition, we give a general mapping connecting suitable classical statistical mechanical models to optimal error correction in subsystem stabilizer codes that suffer from depolarizing noise.

  10. Quantum error-correcting subsystems are unitarily recoverable subsystems

    SciTech Connect

    Kribs, David W.; Spekkens, Robert W.

    2006-10-15

    We show that every correctable subsystem for an arbitrary noise operation can be recovered by a unitary operation, where the notion of recovery is more relaxed than the notion of correction insofar as it does not protect the subsystem from subsequent iterations of the noise. We also demonstrate that in the case of unital noise operations one can identify a subset of all correctable subsystems--those that can be corrected by a single unitary operation--as the noiseless subsystems for the composition of the noise operation with its dual. Using the recently developed structure theory for noiseless subsystems, the identification of such unitarily correctable subsystems is reduced to an algebraic exercise.

  11. Validating predictions made by a thermo-mechanical model of melt segregation in sub-volcanic systems

    NASA Astrophysics Data System (ADS)

    Roele, Katarina; Jackson, Matthew; Morgan, Joanna

    2014-05-01

    A quantitative understanding of the spatial and temporal evolution of melt distribution in the crust is crucial in providing insights into the development of sub-volcanic crustal stratigraphy and composition. This work aims to relate numerical models that describe the base of volcanic systems with geophysical observations. Recent modelling has shown that the repetitive emplacement of mantle-derived basaltic sills, at the base of the lower crust, acts as a heat source for anatectic melt generation, buoyancy-driven melt segregation and mobilisation. These processes form the lowermost architecture of complex sub-volcanic networks as upward migrating melt produces high melt fraction layers. These 'porosity waves' are separated by zones with high compaction rates and have distinctive polybaric chemical signatures that suggest mixed crust and mantle origins. A thermo-mechanical model produced by Solano et al in 2012 has been used to predict the temperatures and melt fractions of successive high porosity layers within the crust. This model was used as it accounts for the dynamic evolution of melt during segregation and migration through the crust; a significant process that has been neglected in previous models. The results were used to input starting compositions for each of the layers into the rhyolite-MELTS thermodynamic simulation. MELTS then determined the approximate bulk composition of the layers once they had cooled and solidified. The mean seismic wave velocities of the polymineralic layers were then calculated using the relevant Voight-Reuss-Hill mixture rules, whilst accounting for the pressure and temperature dependence of seismic wave velocity. The predicted results were then compared with real examples of reflectivity for areas including the UK, where lower crustal layering is observed. A comparison between the impedance contrasts at compositional boundaries is presented as it confirms the extent to which modelling is able to make predictions that are

  12. Lithosphere tectonics and thermo-mechanical properties: An integrated modelling approach for Enhanced Geothermal Systems exploration in Europe

    NASA Astrophysics Data System (ADS)

    Cloetingh, S.; van Wees, J. D.; Ziegler, P. A.; Lenkey, L.; Beekman, F.; Tesauro, M.; Förster, A.; Norden, B.; Kaban, M.; Hardebol, N.; Bonté, D.; Genter, A.; Guillou-Frottier, L.; Ter Voorde, M.; Sokoutis, D.; Willingshofer, E.; Cornu, T.; Worum, G.

    2010-10-01

    Knowledge of temperature at drillable depth is a prerequisite in site selection for geothermal exploration and development of enhanced geothermal systems (EGS). Equally important, the thermo-mechanical signature of the lithosphere and crust provides critical constraints for the crustal stress field and basement temperatures where borehole observations are rare. The stress and temperature field in Europe is subject to strong spatial variations often linked to polyphase extensional and compressional reactivation of the lithosphere, in different modes of deformation. The development of innovative combinations of numerical and analogue modelling techniques is key to thoroughly understand the spatial and temporal variations in crustal stress and temperature. In this paper we present an overview of advances in developing and applying analogue and numerical thermo-mechanical models to quantitatively assess the interplay of lithosphere dynamics and basin (de)formation. Field studies of kinematic indicators and numerical modelling of present-day and paleo-stress fields in selected areas yield new constraints on the causes and the expression of intraplate stress fields in the lithosphere, driving basin (de)formation. The actual basin response to intraplate stress is strongly affected by the rheological structure of the underlying lithosphere, the basin geometry, fault dynamics and interplay with surface processes. Integrated basin studies show that the rheological structure of the lithosphere plays an important role in the spatial and temporal distribution of stress-induced vertical motions, varying from subtle faulting to basin reactivation and large wavelength patterns of lithospheric folding. These findings demonstrate that sedimentary basins are sensitive recorders of the intraplate stress field. The long lasting memory of the lithosphere, in terms of lithospheric scale weak zones, plays a far more important role in basin formation and reactivation than hitherto assumed

  13. Data on synthesis and thermo-mechanical properties of stimuli-responsive rubber materials bearing pendant anthracene groups.

    PubMed

    Manhart, Jakob; Ayalur-Karunakaran, Santhosh; Radl, Simone; Oesterreicher, Andreas; Moser, Andreas; Ganser, Christian; Teichert, Christian; Pinter, Gerald; Kern, Wolfgang; Griesser, Thomas; Schlögl, Sandra

    2016-12-01

    The photo-reversible [4πs+4πs] cycloaddition reaction of pendant anthracene moieties represents a convenient strategy to impart wavelength dependent properties into hydrogenated carboxylated nitrile butadiene rubber (HXNBR) networks. The present article provides the (1)H NMR data on the reaction kinetics of the side chain functionalization of HXNBR. 2-(Anthracene-9-yl)oxirane with reactive epoxy groups is covalently attached to the polymer side chain of HXNBR via ring opening reaction between the epoxy and the carboxylic groups. Along with the identification, (1)H NMR data on the quantification of the attached functional groups are shown in dependence on reaction time and concentration of 2-(anthracene-9-yl)oxirane. Changes in the modification yield are reflected in the mechanical properties and DMA data of photo-responsive elastomers are illustrated in dependence on the number of attached anthracene groups. DMA curves over repeated cycles of UV induced crosslinking (λ>300 nm) and UV induced cleavage (λ=254 nm) are further depicted, demonstrating the photo-reversibility of the thermo-mechanical properties. Interpretation and discussion of the data are provided in "Design and application of photo-reversible elastomer networks by using the [4πs+4πs] cycloaddition reaction of pendant anthracene groups" (Manhart et al., 2016) [1].

  14. The Effect of Thermo-mechanical Processing on the Mechanical Properties of Molybdenum-2 Volume%Lanthana

    SciTech Connect

    A.J. Mueller; R.W. Buckman,Jr.; A.J. Shields,Jr

    2001-03-14

    Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 Volume % La[sub]2O[sub]3 mill product forms, produced by a wet doping process, were characterized over the temperature range of -150 degrees C to 1800 degrees C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved material had superior creep rupture properties to recrystallized material at 1200 degrees C, while at 1500 degrees C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % LA[sub]2O[sub]3 to the demands of the application being considered.

  15. Effect of partially hydrolyzed guar gum on pasting, thermo-mechanical and rheological properties of wheat dough.

    PubMed

    Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

    2016-12-01

    Partially hydrolyzed guar gum was prepared using enzymatic hydrolysis of native guar gum that can be utilized as soluble fiber source. The effect of partially hydrolyzed guar gum (PHGG) on pasting, thermo-mechanical and rheological properties of wheat flour was investigated using rapid visco-analyzer, Mixolab and Microdoughlab. Wheat flour was replaced with 1-5g PHGG per 100g of wheat flour on weight basis. PHGG addition decreased the peak, trough, breakdown, setback and final viscosity of wheat flour. Water absorption and amylase activity of wheat dough were increased whereas starch gelatinization and protein weakening of wheat dough were reduced as a result of PHGG addition to wheat flour. PHGG addition also increased the peak dough height, arrival time, dough development time, dough stability and peak energy of wheat dough system. However, dough softening was decreased after PHGG addition to wheat flour dough. Overall, it can be assumed that PHGG has influenced the properties of wheat flour dough system by decreasing the RVA viscosities and increasing the water absorption and starch gelatinization of wheat dough system.

  16. SIMS evaluation of poly crystal boron nitride tool effect in thermo-mechanically affected zone of friction stir weld steels

    NASA Astrophysics Data System (ADS)

    Kim, JaeNam; Lee, SangUp; Kwun, HyoegDae; Shin, KwangSoo; Kang, ChangYong

    2014-11-01

    The effect of the poly crystal boron nitride (PCBN) tool in friction stir weld (FSW) steels was evaluated using the secondary ion mass spectroscopy (SIMS) technique. This study focused on the quantitative SIMS analysis of impurity boron through a resistive anode encoder (RAE) image. The RAE images were transformed retrospective depth profile by profiler. The relative sensitivity factors (RSFs) for boron varied heavily according to by the polarity of secondary voltage and matrix materials. The RAE images of cluster-polyatomic secondary ion species, 11B16O2, properly map the distribution of impurity boron in the thermo-mechanically affected zone (TMAZ) of FSW steels using negative secondary polarity 4.5 kV. A combination of cluster-polyatomic ion, 11B16O2 and 56Fe16O provided a good calibration curve by 3 SRMs with the least matrix effect. The boron concentrations of TMAZ in FSW steels were determined through the calibration curve by taking the corresponding boron concentration value (CB) of the intensity ratio (Ii/Im) from unknown samples. The new SIMS quantification technique of impurity boron from RAE images is found to be effective for a more quantitative understanding of the wear mechanism of the PCBN tool in TMAZ of FSW steels.

  17. Numerical modeling of inelastic structures at loading of steady state rolling. Thermo-mechanical asphalt pavement computation

    NASA Astrophysics Data System (ADS)

    Wollny, Ines; Hartung, Felix; Kaliske, Michael

    2016-05-01

    In order to gain a deeper knowledge of the interactions in the coupled tire-pavement-system, e.g. for the future design of durable pavement structures, the paper presents recent results of research in the field of theoretical-numerical asphalt pavement modeling at material and structural level, whereby the focus is on a realistic and numerically efficient computation of pavements under rolling tire load by using the finite element method based on an Arbitrary Lagrangian Eulerian (ALE) formulation. Inelastic material descriptions are included into the ALE frame efficiently by a recently developed unsplit history update procedure. New is also the implementation of a viscoelastic cohesive zone model into the ALE pavement formulation to describe the interaction of the single pavement layers. The viscoelastic cohesive zone model is further extended to account for the normal pressure dependent shear behavior of the bonding layer. Another novelty is that thermo-mechanical effects are taken into account by a coupling of the mechanical ALE pavement computation to a transient thermal computation of the pavement cross-section to obtain the varying temperature distributions of the pavement due to climatic impact. Then, each ALE pavement simulation considers the temperature dependent asphalt material model that includes elastic, viscous and plastic behavior at finite strains and the temperature dependent viscoelastic cohesive zone formulation. The temperature dependent material parameters of the asphalt layers and the interfacial layers are fitted to experimental data. Results of coupled tire-pavement computations are presented to demonstrate potential fields of application.

  18. The deformation and acoustic emission of aluminum-magnesium alloy under non-isothermal thermo-mechanical loading

    NASA Astrophysics Data System (ADS)

    Makarov, S. V.; Plotnikov, V. A.; Lysikov, M. V.; Kolubaev, E. A.

    2015-10-01

    The following study investigates the deformation behavior and acoustic emission in aluminum-magnesium alloy under conditions of non-isothermal thermo-mechanical loading. The accumulation of deformation in the alloy, in conditions of change from room temperature to 500°C, occurs in two temperature intervals (I, II), characterized by different rates of deformation. The rate of deformation accumulation is correlated with acoustic emission. With load increasing in cycles from 40 to 200 MPa, the value of the boundary temperature (Tb) between intervals I and II changes non-monotonically. In cycles with load up to 90 MPa, the Tb value increases, while an increase up to 200 MPa makes Tb shift toward lower temperatures. This suggests that the shift of boundaries in the region of low temperatures and the appearance of high-amplitude pulses of acoustic emission characterize the decrease of the magnitude of thermal fluctuations with increasing mechanical load, leading to the rupture of interatomic bonds in an elementary deformation act.

  19. Thermo-mechanical and Microstructural Characterization of Geopolymers with α-Al2O3 Particle Filler

    NASA Astrophysics Data System (ADS)

    Lin, T. S.; Jia, D. C.; He, P. G.; Wang, M. R.

    2009-10-01

    Geopolymers with different content of α-Al2O3 particle filler were prepared. The thermo-mechanical and microstructural characterization of the obtained geopolymers were systematically studied by flexural strength and thermal shrinkage measurements, TG-DTA (thermogravimetry and differential thermal analysis), XRD (X-ray diffractometry), and SEM (scanning electron microscopy). The results show that the addition of α-Al2O3 particle filler not only increases the onset crystalline temperature but also reduces the crystalline velocity of the geopolymers. The thermal shrinkage of the geopolymers increases with increasing heat treatment temperatures due to the water loss and densification. The flexural strength of the geopolymers increases with the increase of heat treatment temperatures from RT to 1200 °C, and shows a sharp increase in the range from 600 °C to 800 °C due to crystallization and solidification. The increase in content of α-Al2O3 particle filler can clearly reduce the thermal shrinkage and maintain a higher porosity at high temperatures. However, it has no distinct influence on the flexural strength after heat treatment. This is mainly attributed to the higher thermal resistance and strength of α-Al2O3.

  20. PERFORMANCE IMPROVEMENT OF CREEP-RESISTANT FERRITIC STEEL WELDMENTS THROUGH THERMO-MECHANICAL TREATMENT AND ALLOY DESIGN

    SciTech Connect

    Yamamoto, Yukinori; Babu, Prof. Sudarsanam Suresh; Shassere, Benjamin; Yu, Xinghua

    2016-01-01

    Two different approaches have been proposed for improvement of cross-weld creep properties of the high temperature ferrous structural materials for fossil-fired energy applications. The traditional creep strength-enhanced ferritic (CSEF) steel weldments suffer from Type IV failures which occur at the fine-grained heat affected zone (FGHAZ). In order to minimize the premature failure at FGHAZ in the existing CSEF steels, such as modified 9Cr-1Mo ferritic-martensitic steels (Grade 91), a thermo-mechanical treatment consisting of aus-forging/rolling and subsequent aus-aging is proposed which promotes the formation of stable MX carbonitrides prior to martensitic transformation. Such MX remains undissolved during welding process, even in FGHAZ, which successfully improves the cross-weld creep properties. Another approach is to develop a new fully ferrtic, creep-resistant FeCrAl alloy which is essentially free from Type IV failure issues. Fe-30Cr-3Al base alloys with minor alloying additions were developed which achieved a combination of good oxidation/corrosion resistance and improved tensile and creep performance comparable or superior to Grade 92 steel.

  1. The deformation and acoustic emission of aluminum-magnesium alloy under non-isothermal thermo-mechanical loading

    SciTech Connect

    Makarov, S. V.; Plotnikov, V. A. Lysikov, M. V.; Kolubaev, E. A.

    2015-10-27

    The following study investigates the deformation behavior and acoustic emission in aluminum-magnesium alloy under conditions of non-isothermal thermo-mechanical loading. The accumulation of deformation in the alloy, in conditions of change from room temperature to 500°C, occurs in two temperature intervals (I, II), characterized by different rates of deformation. The rate of deformation accumulation is correlated with acoustic emission. With load increasing in cycles from 40 to 200 MPa, the value of the boundary temperature (T{sub b}) between intervals I and II changes non-monotonically. In cycles with load up to 90 MPa, the T{sub b} value increases, while an increase up to 200 MPa makes T{sub b} shift toward lower temperatures. This suggests that the shift of boundaries in the region of low temperatures and the appearance of high-amplitude pulses of acoustic emission characterize the decrease of the magnitude of thermal fluctuations with increasing mechanical load, leading to the rupture of interatomic bonds in an elementary deformation act.

  2. Thermo-Mechanical Properties of SiC/SiC Composites with Hybrid CVI-PIP Matrices

    NASA Technical Reports Server (NTRS)

    Bhatt, R. T.; DiCarlo, J. A.

    2004-01-01

    For long term structural service, the upper temperature capability for slurry-cast melt infiltrated (MI) SiC/SiC composites is limited to approx. 1315 C because of silicon reaction with the SiC fibers. For applications requiring material temperatures in excess of 1315 C, alternate methods of manufacturing the SiC matrices without silicon are being investigated, such as a hybrid combination of CVI and PIP. In this study, stacked fabric plies of Sylramic i-BN SiC fibers were coated with a CVI BN interface layer followed by a partial CVI SiC matrix. The remaining porosity in the SiC/SiC preforms was then infiltrated with silicon carbide matrix by PIP. Thermo-mechanical property measurements indicate that these composites are stable to 1700 C in inert environments under no load conditions for 100 h and under load conditions to 1450 C in air for 300 h. The advantages, disadvantages, and potential of this composite system for high temperature applications will be discussed.

  3. Fracture Mechanics Analyses of Subsurface Defects in Reinforced Carbon-Carbon Joggles Subjected to Thermo-Mechanical Loads

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Raju, Ivatury S.; Song, Kyongchan

    2011-01-01

    Coating spallation events have been observed along the slip-side joggle region of the Space Shuttle Orbiter wing-leading-edge panels. One potential contributor to the spallation event is a pressure build up within subsurface voids or defects due to volatiles or water vapor entrapped during fabrication, refurbishment, or normal operational use. The influence of entrapped pressure on the thermo-mechanical fracture-mechanics response of reinforced carbon-carbon with subsurface defects is studied. Plane-strain simulations with embedded subsurface defects are performed to characterize the fracture mechanics response for a given defect length when subjected to combined elevated-temperature and subsurface-defect pressure loadings to simulate the unvented defect condition. Various subsurface defect locations of a fixed-length substrate defect are examined for elevated temperature conditions. Fracture mechanics results suggest that entrapped pressure combined with local elevated temperatures have the potential to cause subsurface defect growth and possibly contribute to further material separation or even spallation. For this anomaly to occur, several unusual circumstances would be required making such an outcome unlikely but plausible.

  4. Surface and thermal enhancement of the cellulosic component of thermo mechanical pulp using a rapid method: Iodomethane modification.

    PubMed

    George, Michael; Mussone, Paolo G; Bressler, David C

    2016-05-20

    The feasibility of employing chemical methods for enhancement of cellulose-based materials is dependent on the availability, price, and green index of the modifying agent. This study details the use of iodomethane, an inexpensive organo halide, to increase the hydrophobicity of thermo mechanical (TMP) samples, which renders them better structural elements for composite materials. For this system, we studied the influence of various concentration of iodomethane, concentration of caustic, and reaction time. Infrared spectroscopy suggested reaction of the organo halide with the hydroxyl groups of cellulose and lignin components of TMP. Pulp samples treated for 4 h or at low caustic concentration showed the least improvements plausibly due to pulp degradation or poor pulp swelling, respectively. On the other hand, pulp treated at 3 h using high concentrations of caustic were characterized with surfaces that were more hydrophobic. Thus, this study outlines a fast and organic solvent-free (clean up) method that can be used to enhance pulp samples for composite applications.

  5. Atomic force microscopy applied to the quantification of nano-precipitates in thermo-mechanically treated microalloyed steels

    SciTech Connect

    Renteria-Borja, Luciano; Hurtado-Delgado, Eduardo; Garnica-Gonzalez, Pedro; Dominguez-Lopez, Ivan; Garcia-Garcia, Adrian Luis

    2012-07-15

    Quantification of nanometer-size precipitates in microalloyed steels has been traditionally performed using transmission electron microscopy (TEM), in spite of its complicated sample preparation procedures, prone to preparation errors and sample perturbation. In contrast to TEM procedures, atomic force microscopy (AFM) is performed on the as-prepared specimen, with sample preparation requirements similar to those for optical microscopy (OM), rendering three-dimensional representations of the sample surface with vertical resolution of a fraction of a nanometer. In AFM, contrast mechanisms are directly related to surface properties such as topography, adhesion, and stiffness, among others. Chemical etching was performed using 0.5% nital, at time intervals between 4 and 20 s, in 4 s steps, until reaching the desired surface finish. For the present application, an average surface-roughness peak-height below 200 nm was sought. Quantification results of nanometric precipitates were obtained from the statistical analysis of AFM images of the microstructure developed by microalloyed Nb and V-Mo steels. Topography and phase contrast AFM images were used for quantification. The results obtained using AFM are consistent with similar TEM reports. - Highlights: Black-Right-Pointing-Pointer We quantified nanometric precipitates in Nb and V-Mo microalloyed steels using AFM. Black-Right-Pointing-Pointer Microstructures of the thermo-mechanically treated microalloyed steels were used. Black-Right-Pointing-Pointer Topography and phase contrast AFM images were used for quantification. Black-Right-Pointing-Pointer AFM results are comparable with traditionally obtained TEM measurements.

  6. Pressure Garment Subsystem Roadmap

    NASA Technical Reports Server (NTRS)

    Ross, Amy J.

    2010-01-01

    The Constellation program pressure garment subsystem (PGS) team has created a technical roadmap that communicates major technical questions and how and when the questions are being answered in support of major project milestones. The roadmap is a living document that guides the team priorities. The roadmap also communicates technical reactions to changes in project priorities and funding. This paper presents the roadmap and discusses specific roadmap elements in detail as representative examples to provide insight into the meaning and use of the roadmap.

  7. NEP power subsystem modeling

    NASA Astrophysics Data System (ADS)

    Harty, Richard B.

    The Nuclear Electric Propulsion (NEP) system optimization code consists of a master module and various submodules. Each of the submodules represents a subsystem within the total NEP power system. The master module sends commands and input data to each of the submodules and receives output data back. Rocketdyne was responsible for preparing submodules for the power conversion (both K-Rankine and Brayton), heat rejection, and power management and distribution.

  8. The MAP Propulsion Subsystem

    NASA Technical Reports Server (NTRS)

    Davis, Gary T.; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    This paper describes the requirements, design, integration, test, performance, and lessons learned of NASA's Microwave Anisotropy Probe (MAP) propulsion subsystem. MAP was launched on a Delta-II launch vehicle from NASA's Kennedy Space Center on June 30, 2001. Due to instrument thermal stability requirements, the Earth-Sun L2 Lagrange point was selected for the mission orbit. The L2 trajectory incorporated phasing loops and a lunar gravity assist. The propulsion subsystem's requirements are to manage momentum, perform maneuvers during the phasing loops to set up the lunar swingby, and perform stationkeeping at L2 for 2 years. MAP's propulsion subsystem uses 8 thrusters which are located and oriented to provide attitude control and momentum management about all axes, and delta-V in any direction without exposing the instrument to the sun. The propellant tank holds 72 kg of hydrazine, which is expelled by unregulated blowdown pressurization. Thermal management is complex because no heater cycling is allowed at L2. Several technical challenges presented themselves during I and T, such as in-situ weld repairs and in-situ bending of thruster tubes to accommodate late changes in the observatory CG. On-orbit performance has been nominal, and all phasing loop, mid-course correction, and stationkeeping maneuvers have been successfully performed to date.

  9. Directional solidification, thermo-mechanical and optical properties of (Mg(x)Ca(1-x))(3)Al(2)Si(3)O(12) glasses doped with Nd(3+) ions.

    PubMed

    Sola, D; Conejos, D; Martínez de Mendivil, J; Ortega-San-Martín, L; Lifante, G; Peña, J I

    2015-10-05

    In this work glass rods of (Mg(x)Ca(1-x))(3)Al(2)Si(3)O(12) (x = 0, 0.5 and 1) doped with 1 wt% Nd(2)O(3) were produced by the laser floating zone technique. Thermo-mechanical and spectroscopic properties have been evaluated. The three glass samples present good thermo-mechanical properties, with similar hardness, toughness and glass transition temperatures. The spectroscopic characterization shows spectral shifts in absorption and emission spectra. These spectral shifts together with Judd-Ofelt intensity parameters and ionic packing ratio have been used to investigate the local structure surrounding the Nd(3+) ions and the covalency of the Nd-O bond. All obtained results agree and confirm the higher covalency of the Nd-O bond in the Ca(3)Al(2)Si(3)O(12) glass.

  10. Thermo-Mechanical Response of Monolithic and NiTi Shape Memory Alloy Fiber Reinforced Sn-3.8Ag-0.7Cu Solder

    DTIC Science & Technology

    2005-09-01

    still exist from this high thermal mismatch deformation , resulting in large solder-joint stresses and strains and causing fatigue failure. The...life, but have not shown the needed improvements in thermo-mechanical fatigue life under strain - controlled conditions, which is a primary deformation ...A NiTi fiber will deform until it consists only of the correspondence variant (crystallographic orientation) that produces maximum strain . However

  11. Effect of thermo-mechanical cycling on zirconium hydride reorientation studied in situ with synchrotron X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Colas, Kimberly B.; Motta, Arthur T.; Daymond, Mark R.; Almer, Jonathan D.

    2013-09-01

    The circumferential hydrides normally present in nuclear reactor fuel cladding after reactor exposure may dissolve during drying for dry storage and re-precipitate when cooled under load into a more radial orientation, which could embrittle the fuel cladding. It is necessary to study the rates and conditions under which hydride reorientation may happen in order to assess fuel integrity in dry storage. The objective of this work is to study the effect of applied stress and thermal cycling on the hydride morphology in cold-worked stress-relieved Zircaloy-4 by combining conventional metallography and in situ X-ray diffraction techniques. Metallography is used to study the evolution of hydride morphology after several thermo-mechanical cycles. In situ X-ray diffraction performed at the Advanced Photon Source synchrotron provides real-time information on the process of hydride dissolution and precipitation under stress during several thermal cycles. The detailed study of diffracted intensity, peak position and full-width at half-maximum provides information on precipitation kinetics, elastic strains and other characteristics of the hydride precipitation process. The results show that thermo-mechanical cycling significantly increases the radial hydride fraction as well as the hydride length and connectivity. The radial hydrides are observed to precipitate at a lower temperature than circumferential hydrides. Variations in the magnitude and range of hydride strains due to reorientation and cycling have also been observed. These results are discussed in light of existing models and experiments on hydride reorientation. The study of hydride elastic strains during precipitation shows marked differences between circumferential and radial hydrides, which can be used to investigate the reorientation process. Cycling under stress above the threshold stress for reorientation drastically increases both the reoriented hydride fraction and the hydride size. The reoriented hydride

  12. System analysis with improved thermo-mechanical fuel rod models for modeling current and advanced LWR materials in accident scenarios

    NASA Astrophysics Data System (ADS)

    Porter, Ian Edward

    A nuclear reactor systems code has the ability to model the system response in an accident scenario based on known initial conditions at the onset of the transient. However, there has been a tendency for these codes to lack the detailed thermo-mechanical fuel rod response models needed for accurate prediction of fuel rod failure. This proposed work will couple today's most widely used steady-state (FRAPCON) and transient (FRAPTRAN) fuel rod models with a systems code TRACE for best-estimate modeling of system response in accident scenarios such as a loss of coolant accident (LOCA). In doing so, code modifications will be made to model gamma heating in LWRs during steady-state and accident conditions and to improve fuel rod thermal/mechanical analysis by allowing axial nodalization of burnup-dependent phenomena such as swelling, cladding creep and oxidation. With the ability to model both burnup-dependent parameters and transient fuel rod response, a fuel dispersal study will be conducted using a hypothetical accident scenario under both PWR and BWR conditions to determine the amount of fuel dispersed under varying conditions. Due to the fuel fragmentation size and internal rod pressure both being dependent on burnup, this analysis will be conducted at beginning, middle and end of cycle to examine the effects that cycle time can play on fuel rod failure and dispersal. Current fuel rod and system codes used by the Nuclear Regulatory Commission (NRC) are compilations of legacy codes with only commonly used light water reactor materials, Uranium Dioxide (UO2), Mixed Oxide (U/PuO 2) and zirconium alloys. However, the events at Fukushima Daiichi and Three Mile Island accident have shown the need for exploration into advanced materials possessing improved accident tolerance. This work looks to further modify the NRC codes to include silicon carbide (SiC), an advanced cladding material proposed by current DOE funded research on accident tolerant fuels (ATF). Several

  13. A new code for predicting the thermo-mechanical and irradiation behavior of metallic fuels in sodium fast reactors

    NASA Astrophysics Data System (ADS)

    Karahan, Aydın; Buongiorno, Jacopo

    2010-01-01

    An engineering code to predict the irradiation behavior of U-Zr and U-Pu-Zr metallic alloy fuel pins and UO2-PuO2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named Fuel Engineering and Structural analysis Tool (FEAST). FEAST has several modules working in coupled form with an explicit numerical algorithm. These modules describe fission gas release and fuel swelling, fuel chemistry and restructuring, temperature distribution, fuel-clad chemical interaction, and fuel and clad mechanical analysis including transient creep-fracture for the clad. Given the fuel pin geometry, composition and irradiation history, FEAST can analyze fuel and clad thermo-mechanical behavior at both steady-state and design-basis (non-disruptive) transient scenarios. FEAST was written in FORTRAN-90 and has a simple input file similar to that of the LWR fuel code FRAPCON. The metal-fuel version is called FEAST-METAL, and is described in this paper. The oxide-fuel version, FEAST-OXIDE is described in a companion paper. With respect to the old Argonne National Laboratory code LIFE-METAL and other same-generation codes, FEAST-METAL emphasizes more mechanistic, less empirical models, whenever available. Specifically, fission gas release and swelling are modeled with the GRSIS algorithm, which is based on detailed tracking of fission gas bubbles within the metal fuel. Migration of the fuel constituents is modeled by means of thermo-transport theory. Fuel-clad chemical interaction models based on precipitation kinetics were developed for steady-state operation and transients. Finally, a transient intergranular creep-fracture model for the clad, which tracks the nucleation and growth of the cavities at the grain boundaries, was developed for and implemented in the code. Reducing the empiricism in the constitutive models should make it more acceptable to extrapolate FEAST-METAL to new fuel compositions and higher burnup, as envisioned in advanced sodium reactors

  14. Conformal array antenna subsystem

    NASA Astrophysics Data System (ADS)

    1985-04-01

    An antenna subsystem to communicate between Ariane 4 and a data relay satellite was studied, concluding that the original ideas on ring antennas should be corrected due to the wide margin of coverage required in elevation for such antennas, which implies the need of splitting the coverage. Nevertheless, the study of cylindrical and conical conformal arrays was continued in view of their intrinsic interest. Needed coverages with specified gain can be obtained with a set of microstrip circular patch antennas. For the lower stage, a single patch is enough. For geostationary missions, one horizontal array is used, and for heliosynchronous missions two horizontal arrays and a vertical one. The numerical study carried out on omniazimuthal ring antennas shows that a tendency to omnidirectional pattern exists in spite of the directivity of the elementary radiators. A small pointing improvement of the meridian pattern can be obtained by means of conical arrays instead of the cylindrical ones.

  15. Fuel Subsystems Flight Test Handbook

    DTIC Science & Technology

    1981-12-01

    aircraft fuel subsystems and the requirements to which they are designed . Details are provided of individual testes, test support requirements and eval...Flight Test Engineering, AFFTC. It is designed to introduce a newly assigned flight test engineer to the subject and provide a working reference for...Refueling Subsystem 17 Fuel Dump Subsystem 18 Heat Exchangers 18 REVIEW OF DESIGN AND TEST REQUIREMENTS 19 Classification of Requirements Other Than 20

  16. Constrains on Crustal Accretion Obtained from Cooling Rate Calculations with a Thermo-Mechanical Model of Fast-Spreading Mid-Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Garrido, C. J.; Machetel, P.

    2012-12-01

    We have used a thermo-mechanical model designed to find steady-state solutions of motion and temperature with variable viscosity, heat diffusion, heat advection, hydrothermal cooling and latent heat release. Cases analogous to the "gabbro glacier" (G accretion structure), "sheeted sills" (S structure) and "mixed shallow and MTZ lenses" (M structure) were computed with and without sheeted dyke level modeling. The results show that thermal patterns near the ridge mainly depend on hydrothermal cooling. Several hydrothermal cooling cracking temperature have been used in order to illustrate the present scientific debate on the penetration depth and efficiency of hydrothermal flows. Second, higher cooling rates are obtained for the G structures. Third, whereas the subsolidus cooling rates, SCR, decrease monotonically with depth, the igneous cooling rates, ICR, display local minima at the merging levels of the upper and lower lenses. It appears that ICR reveal the near-ridge thermal and mechanical structures, whereas the lower value of the initial-to-closure temperature ranges used for SCR cause shifts farther from the ridge that reduces the ability of SCR to discriminate the ridge thermo-mechanical configuration. It also indicates that the common assumption that ICR and SCR should be similar is probably over-simplified. Finally, the cooling rates obtained bears the clear signature of the three intrusion hypothesis. The results show that numerical modeling of the lower crust's thermo-mechanical properties may provide new insights to discriminate among hypotheses related to G, M and S structures for fast-spreading ridges.; Thermal history obtained for the Gabro Glacier (top panels), Mixed shallow and MTZ zone (middle panels) and Sheeted Sills hypothesis (bottom panels)for the magma intrusion at ridge. Columns corresponds to various hydrothermal cooling and viscosity hypothesis.

  17. Thermo-Mechanical Optimization of a Gold Thick-film based SiC Die-attach Assembly using Finite Element Analysis

    NASA Technical Reports Server (NTRS)

    Lin, Shun-Tien; Chen, Liang-Yu

    2002-01-01

    A parametric study of the thermomechanical reliability of a Au thick-film based Sic-die- attach assembly using nonlinear finite element analysis (FEA) was conducted to optimize the die-attach thermo-mechanical performance for operation at temperatures from room temperature to 500 "C. This parametric study centered on material selection, structure design and process control. The die-attach assembly is composed of a 1 mm x 1 mm S i c die attached to a ceramic substrate (either 96% aluminum oxide (A1203) or aluminum nitride (AlN)) with a gold (Au) thick-film attach layer. The effects of die-size, Au attach layer thickness, substrate material, and stress relaxing temperature on the stress/strain distribution and relative fatigue lifetime of the die-attach assembly were numerically analyzed. By comparing the calculated permanent strain in the thick-film attach layer, FEA results indicate that AlN is superior to Al2O3. Thicker Au attach layers and smaller die sizes are recommended to reduce the permanent strain in thick-film die attach layer. Thicker S i c die also reduces the stress near the (top) surface region of the die. A stress relaxing temperature close to the midpoint of the operating temperature range further reduces the maximum stress/strain, thereby improving die-attach thermo-mechanical reliability. These recommendations present guidelines to optimize the thermo-mechanical performance of the die-attach assembly and are valid for a wide range of thermal environments.

  18. In-situ neutron diffraction study of martensitic variant redistribution in polycrystalline Ni-Mn-Ga alloy under cyclic thermo-mechanical treatment

    SciTech Connect

    Li, Zongbin; Zou, Naifu; Zhao, Xiang; Zuo, Liang E-mail: yudong.zhang@univ-lorraine.fr; Zhang, Yudong E-mail: yudong.zhang@univ-lorraine.fr; Esling, Claude; Gan, Weimin

    2014-07-14

    The influences of uniaxial compressive stress on martensitic transformation were studied on a polycrystalline Ni-Mn-Ga bulk alloy prepared by directional solidification. Based upon the integrated in-situ neutron diffraction measurements, direct experimental evidence was obtained on the variant redistribution of seven-layered modulated (7M) martensite, triggered by external uniaxial compression during martensitic transformation. Large anisotropic lattice strain, induced by the cyclic thermo-mechanical treatment, has led to the microstructure modification by forming martensitic variants with a strong 〈0 1 0〉{sub 7M} preferential orientation along the loading axis. As a result, the saturation of magnetization became easier to be reached.

  19. Thermo-mechanical modeling of continental rift evolution over mantle upwelling in presence of far-field stresses

    NASA Astrophysics Data System (ADS)

    Koptev, Alexander; Burov, Evgueni; Calais, Eric; Leroy, Sylvie; Gerya, Taras

    2016-04-01

    We conducted fully-coupled high resolution rheologically consistent 3D thermo-mechanical numerical models to investigate the processes of mantle-lithosphere interaction (MLI) in presence of preexisting far-field tectonic stresses. MLI-induced topography exhibits strongly asymmetric small-scale 3D features, such as rifts, flexural flank uplifts and complex faults structures. This suggests a dominant role of continental rheological structure and intra-plate stresses in controlling continental rifting and break-up processes above mantle upwelling while reconciling the passive (far-field tectonic stresses) versus active (plume-activated) rift concepts as our experiments show both processes in action. We tested different experiments by varying two principal controlling parameters: 1) horizontal extension velocity and 2) Moho temperature used as simplified indicator of the thermal and rheological lithosphere layering. An increase in the applied extension expectedly gives less localized deformation at lithospheric scale: the growth of external velocity from 1.5 mm/years to 6 mm/years leads to enlargement of the rift zones from 75-175 km to 150-425 km width. On the contrary, increasing of the lithospheric geotherm has an opposite effect leading to narrowing of the rift zone: the change of the Moho isotherm from 600°C to 800°C causes diminution of the rift width from 175-425 km to 75-150 km. Some of these finding are contra-intuitive in terms of usual assumptions. The models refer to strongly non-linear impact of far-field extension rates on timing of break-up processes. Experiments with relatively fast far-field extension (6 mm/years) show intensive normal fault localization in crust and uppermost mantle above the plume head at 15-20 Myrs after the onset of the experiment. When plume head material reaches the bottom of the continental crust (at 25 Myrs), the latter is rapidly ruptured (<1 Myrs) and several steady oceanic floor spreading centers develop. Slower (3 mm

  20. Simulation of the irradiation-induced micro-thermo-mechanical behaviors evolution in ADS nuclear fuel pellets

    NASA Astrophysics Data System (ADS)

    Ding, Shurong; Zhao, Yunmei; Wan, Jibo; Gong, Xin; Wang, Canglong; Yang, Lei; Huo, Yongzhong

    2013-11-01

    An Accelerator Driven System (ADS) is dedicated to Minor Actinides (MA) transmutation. The fuels for ADS are highly innovative, which are composite fuel pellets with the fuel particles containing MA phases dispersed in a MgO or Mo matrix. Assuming that the fuel particles are distributed periodically in the MgO matrix, a three-dimensional finite element model is developed. The three-dimensional incremental large-deformation constitutive relations for the fuel particles and matrix are separately built, and a method is accordingly constructed to implement simulation of the micro-thermo-mechanical behaviors evolution. Evolutions of the temperature and mechanical fields are given and discussed. With irradiation creep included in the MgO matrix constitutive relation, the conclusions can be drawn as that (1) irradiation creep has a remarkable effect on the mechanical behaviors evolution in the matrix; (2) irradiation creep plays an important role in the damage mechanism interpretation of ceramic matrix fuel pellets. Thermal conductivity The thermal conductivity model is adopted as KUO2 = K0·FD·FP·FM·FR, which was proposed by Lucuta et al. [10] to adapt to the high burnup conditions with consideration of the effects of temperature, burnup, porosity and fission products. K0 is the thermal conductivity of fully dense un-irradiated UO2, as Eq. (1) in W/m K; FD, FP are the adjust factors reflecting the effects of dissolved and precipitated fission products; FM and FR are factors due to porosity and irradiation effects. The adopted thermal conductivity varies with temperature and burnup, which expresses its degradation with burnup, with the terms as k0={1}/{0.0375+2.165×10-4T}+{4.715×109}/{T2}exp-{16361}/{T} FD={1.09}/{B3.265}+{0.0643}/{√{B}}√{T}artan{1}/{1.09/B3.265}+{0.0643}/{√{B}}√{T} FP=1+0.019B/3-0.019B{1}/{1+exp(1200-T100)} FM={1-P}/{1+(s-1)P} FR=1-{0.2}/{1+expT-90080} Thermal expansion The engineering strain of thermal expansion [11] is given as {ΔL}/{L0

  1. Waste collection subsystem study

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Practical ways were explored of improving waste compaction and of providing rapid turnaround between flights at essentially no cost for the space shuttle waste collection subsystem commode. Because of the possible application of a fully developed shuttle commode to the space station, means of providing waste treatment without overboard venting were also considered. Three basic schemes for compaction and rapid turnaround, each fully capable of meeting the objectives, were explored in sufficient depth to bring out the characteristic advantages and disadvantages of each. Tradeoff comparisons were very close between leading contenders and efforts were made to refine the design concepts sufficiently to justify a selection. The concept selected makes use of a sealed canister containing wastes that have been forcibly compacted, which is removable in flight. No selection was made between three superior non-venting treatment methods owing to the need for experimental evaluations of the processes involved. A system requirements definition document has been prepared to define the task for a test embodiment of the selected concept.

  2. Thermo-mechanical Characterization of Metal/Polymer Composite Filaments and Printing Parameter Study for Fused Deposition Modeling in the 3D Printing Process

    NASA Astrophysics Data System (ADS)

    Hwang, Seyeon; Reyes, Edgar I.; Moon, Kyoung-sik; Rumpf, Raymond C.; Kim, Nam Soo

    2015-03-01

    New metal/polymer composite filaments for fused deposition modeling (FDM) processes were developed in order to observe the thermo-mechanical properties of the new filaments. The acrylonitrile butadiene styrene (ABS) thermoplastic was mixed with copper and iron particles. The percent loading of the metal powder was varied to confirm the effects of metal particles on the thermo-mechanical properties of the filament, such as tensile strength and thermal conductivity. The printing parameters such as temperature and fill density were also varied to see the effects of the parameters on the tensile strength of the final product which was made with the FDM process. As a result of this study, it was confirmed that the tensile strength of the composites is decreased by increasing the loading of metal particles. Additionally, the thermal conductivity of the metal/polymer composite filament was improved by increasing the metal content. It is believed that the metal/polymer filament could be used to print metal and large-scale 3-dimensional (3D) structures without any distortion by the thermal expansion of thermoplastics. The material could also be used in 3D printed circuits and electromagnetic structures for shielding and other applications.

  3. Development of thermo-mechanical processing for fabricating highly durable β-type Ti-Nb-Ta-Zr rod for use in spinal fixation devices.

    PubMed

    Narita, Kengo; Niinomi, Mitsuo; Nakai, Masaaki; Hieda, Junko; Oribe, Kazuya

    2012-05-01

    The mechanical strength of a beta titanium alloy such as Ti-Nb-Ta-Zr alloy (TNTZ) can be improved significantly by thermo-mechanical treatment. In this study, TNTZ was subjected to solution treatment, cold caliber rolling, and cold swaging before aging treatment to form a rod for spinal fixation. The {110}(β) are aligned parallel to the cross-section with two strong peaks approximately 180° apart, facing one another, in the TNTZ rods subjected to cold caliber rolling and six strong peaks at approximately 60° intervals, facing one another, in the TNTZ rods subjected to cold swaging. Therefore, the TNTZ rods subjected to cold swaging have a more uniform structure than those subjected to cold caliber rolling. The orientation relationship between the α and β phases is different. A [110](β)//[121](α), (112)(β)//(210)(α) orientation relationship is observed in the TNTZ rods subjected to aging treatment at 723 K after solution treatment and cold caliber rolling. On the other hand, a [110](β)//[001](α), (112)(β)//(200)(α) orientation relationship is observed in TNTZ rod subjected to aging treatment at 723 K after cold swaging. A high 0.2% proof stress of about 1200 MPa, high elongation of 18%, and high fatigue strength of 950 MPa indicate that aging treatment at 723 K after cold swaging is the optimal thermo-mechanical process for a TNTZ rod.

  4. Thermo-Mechanical Response of a TRISO Fuel Particle in a Fusion/Fission Engine for Incineration of Weapons Grade Plutonium

    SciTech Connect

    Caro, M; DeMange, P; Marian, J; Caro, A

    2009-12-08

    The Laser Inertial Fusion-based (LIFE) engine is an advanced energy concept under development at Lawrence Livermore National Laboratory (LLNL). LIFE engine could be used to drive a subcritical fission blanket with fertile or fissile fuel. Current LIFE engine designs envisages fuel in pebble bed form with TRISO (tristructural isotropic) particles embedded in a graphite matrix, and pebbles flowing in molten salt Flibe (2LiF+BeF{sub 2}) coolant at T {approx} 700C. Weapons-grade plutonium (WGPu) fuel is an attractive option for LIFE engine involving the achievement of high fractional burnups in a short lifetime frame. However, WGPu LIFE engine operating conditions of high neutron fast fluence, high radiation damage, and high Helium and Hydrogen production pose severe challenges for typical TRISO particles. The thermo-mechanical fuel performance code HUPPCO (High burn-Up fuel Pebble Performance COde) currently under development accounts for spatial and time dependence of the material elastic properties, temperature, and irradiation swelling and creep mechanisms. In this work, some aspects of the thermo-mechanical response of TRISO particles used for incineration of weapons grade fuel in LIFE engine are analyzed. Preliminary results show the importance of developing reliable high-fidelity models of the performance of these new fuel designs and the need of new experimental data relevant to WGPu LIFE conditions.

  5. Effect of Multipass TIG and Activated TIG Welding Process on the Thermo-Mechanical Behavior of 316LN Stainless Steel Weld Joints

    NASA Astrophysics Data System (ADS)

    Ganesh, K. C.; Balasubramanian, K. R.; Vasudevan, M.; Vasantharaja, P.; Chandrasekhar, N.

    2016-04-01

    The primary objective of this work was to develop a finite element model to predict the thermo-mechanical behavior of an activated tungsten inert gas (ATIG)-welded joint. The ATIG-welded joint was fabricated using 10 mm thickness of 316LN stainless steel plates in a single pass. To distinguish the merits of ATIG welding process, it was compared with manual multipass tungsten inert gas (MPTIG)-welded joint. The ATIG-welded joint was fabricated with square butt edge configuration using an activating flux developed in-house. The MPTIG-welded joint was fabricated in thirteen passes with V-groove edge configuration. The finite element model was developed to predict the transient temperature, residual stress, and distortion of the welded joints. Also, microhardness, impact toughness, tensile strength, ferrite measurement, and microstructure were characterized. Since most of the recent publications of ATIG-welded joint was focused on the molten weld pool dynamics, this research work gives an insight on the thermo-mechanical behavior of ATIG-welded joint over MPTIG-welded joint.

  6. Thermo-mechanical vibration of a single-layer graphene sheet and a single-walled carbon nanotube on a substrate

    NASA Astrophysics Data System (ADS)

    Ding, Dongqing; Yang, Zhaoyao; Dong, Shuhong; Yu, Peishi; Zhao, Junhua

    2017-03-01

    The thermo-mechanical vibration of a single-layer graphene sheet (SLGP) and a single-walled carbon nanotube (SWCNT) on a substrate is studied by using a nonlocal elastic plate model and two nonlocal elastic beam models (including Timoshenko-beam model and Euler-beam model) with quantum effects, respectively. The effect of the van der Waals (vdW) interactions between the SLGP (or the SWCNT) and the substrate on the vibration is obtained. Checking against our molecular dynamics simulations shows that the present models are reasonable. In particular, the radial vibration of the SWCNT on the substrate with quantum effects is further derived through the continuum shell model due to the different vdW forces on each point of the SWCNT circumference. The present models show that the normalized transverse frequency decreases and the normalized radial frequency increases with increasing SWCNT radius, respectively. The radial amplitude of the SWCNT (or the amplitude of the SLGP) nonlinearly increases and the transverse amplitude of the SWCNT linearly increases with increasing temperature for a given distance, respectively. The obtained analytical solution should be of great importance for understanding the thermo-mechanical vibration of nanoelectronic devices on a substrate.

  7. Influence of the interface structure on the thermo-mechanical properties of Cu-X (X = Cr or B)/carbon fiber composites

    SciTech Connect

    Veillere, A.; Heintz, J.-M.; Chandra, N.; Douin, J.; Lahaye, M.; Lalet, G.; Vincent, C.; Silvain, J.-F.

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Two copper alloys/carbon fibers composites have been produced. Black-Right-Pointing-Pointer Correlation of the thermo-mechanical properties with the microstructure and the chemistry. Black-Right-Pointing-Pointer A composite with CTE 25% lower than a classic Cu/CF composite has been obtained. -- Abstract: This study focuses on the fabrication, for power electronics applications, of adaptive heat sink material using copper alloys/carbon fibers (CF) composites. In order to obtain composite material with good thermal conductivity and a coefficient of thermal expansion close to the ceramic substrate, it is necessary to have a strong matrix/reinforcement bond. Since there is no reaction between copper and carbon, a carbide element (chromium or boron) is added to the copper matrix to create a strong chemical bond. Composite materials (Cu-B/CF and Cu-Cr/CF) have been produced by a powder metallurgy process followed by an annealing treatment in order to create the carbide at the interphase. Chemical (Electron Probe Micro-Analysis, Auger Electron Spectroscopy) and microstructural (Scanning and Transmission Electron Microscopies) techniques were used to study the location of the alloying element and the carbide formation before and after diffusion. Finally, the thermo-mechanical properties have been measured and a promising composite material with a coefficient of thermal expansion 25% lower than a classic copper/carbon heat sink has been obtained.

  8. Spacecraft Design Thermal Control Subsystem

    NASA Technical Reports Server (NTRS)

    Miyake, Robert N.

    2003-01-01

    This slide presentation reviews the functions of the thermal control subsystem engineers in the design of spacecraft. The goal of the thermal control subsystem that will be used in a spacecraft is to maintain the temperature of all spacecraft components, subsystems, and all the flight systems within specified limits for all flight modes from launch to the end of the mission. For most thermal control subsystems the mass, power and control and sensing systems must be kept below 10% of the total flight system resources. This means that the thermal control engineer is involved in all other flight systems designs. The two concepts of thermal control, passive and active are reviewed and the use of thermal modeling tools are explained. The testing of the thermal control is also reviewed.

  9. Subsystems component definitions summary program

    NASA Technical Reports Server (NTRS)

    Scott, A. Don; Thomas, Carolyn C.; Simonsen, Lisa C.; Hall, John B., Jr.

    1991-01-01

    A computer program, the Subsystems Component Definitions Summary (SUBCOMDEF), was developed to provide a quick and efficient means of summarizing large quantities of subsystems component data in terms of weight, volume, resupply, and power. The program was validated using Space Station Freedom Program Definition Requirements Document data for the internal and external thermal control subsystem. Once all component descriptions, unit weights and volumes, resupply, and power data are input, the user may obtain a summary report of user-specified portions of the subsystem or of the entire subsystem as a whole. Any combination or all of the parameters of wet and dry weight, wet and dry volume, resupply weight and volume, and power may be displayed. The user may vary the resupply period according to individual mission requirements, as well as the number of hours per day power consuming components operate. Uses of this program are not limited only to subsystem component summaries. Any applications that require quick, efficient, and accurate weight, volume, resupply, or power summaries would be well suited to take advantage of SUBCOMDEF's capabilities.

  10. Thermo-mechanical processing of sugar beet pulp. III. Study of extruded films improvement with various plasticizers and cross-linkers.

    PubMed

    Rouilly, A; Geneau-Sbartaï, C; Rigal, L

    2009-06-01

    Thermoplastic sugar beet pulp (thermo-mechanical processing was discussed in previous studies) was formed into film strips by extrusion. Film tensile properties are discussed according to the molecular structure of external plasticizer. Sorbitol, fructose and adipic acid have a marked antiplasticizing effect, while urea and xylitol gave higher ultimate tensile stress than glycerol for a comparable strain at break. Xylitol can be considered as the best plasticizer with UTS and EL of, respectively, 4.9 MPa and 11.3% and water absorption (85% RH, 25 degrees C) was less than 25%. Glycidyl methacrylate was directly used in the extrusion process as cross-linker. In high humidity atmosphere (97% RH, 25 degrees C), film water absorption was then kept under 40% while tensile strength and strain were improved of 50% and with a 30 min UV post-treatment the mass gain in absorption was even less than 30% after 5 days.

  11. Preliminary Safety Analysis of the Gorleben Site: Thermo-mechanical Analysis of the Integrity of the Geological Barrier in the Gorleben Salt Formation - 13307

    SciTech Connect

    Eickemeier, R.; Heusermann, S.; Nipp, H.K.; Knauth, M.; Minkley, W.; Popp, T.

    2013-07-01

    Exploration work at the Gorleben salt dome has been carried out since 1977 to investigate the site regarding its suitability as a final repository for high-level radioactive wastes. In the framework of the 'Preliminary Safety Analysis of the Gorleben Site' a comprehensive assessment is being performed with focus on long-term safety. Because the integrity of the geological barrier is crucial for protection from damage caused by ionising radiation during the post-operational phase, 2D and 3D thermo-mechanical calculations for a reference section through the salt dome were carried out, all looking at two different waste emplacement concepts: emplacement in drifts and in boreholes. The calculated stresses are the basis for evaluating the barrier integrity on the basis of the dilatancy criterion and the fluid pressure criterion. (authors)

  12. i RadMat: A thermo-mechanical testing system for in situ high-energy X-ray characterization of radioactive specimens

    DOE PAGES

    Zhang, Xuan; Xu, Chi; Wang, Leyun; ...

    2017-01-27

    Here, we present an in situ Radiated Materials (iRadMat) experimental module designed to interface with a servo-hydraulic load frame for X-ray measurements at beamline 1-ID at the Advanced Photon Source. This new capability allows in situ studies of radioactive specimens subject to thermo-mechanical loading using a suite of high-energy X-ray scattering and imaging techniques. The iRadMat is a radiation-shielded vacuum heating system with the sample rotation-under-load capability. We describe the design features and performances of the iRadMat and present a dataset from a 300 °C uniaxial tensile test of a neutron-irradiated pure Fe specimen to demonstrate its capabilities.

  13. Specification of CuCrZr Alloy Properties after Various Thermo-Mechanical Treatments and Design Allowables including Neutron Irradiation Effects

    SciTech Connect

    Barabash, Vladimir; Kalinin, G. M.; Fabritsiev, Sergei A.; Zinkle, Steven J

    2012-01-01

    Precipitation hardened CuCrZr alloy is a promising heat sink and functional material for various applica- tions in ITER, for example the first wall, blanket electrical attachment, divertor, and heating systems. Three types of thermo-mechanical treatment were identified as most promising for the various applica- tions in ITER: solution annealing, cold working and ageing; solution annealing and ageing; solution annealing and ageing at non-optimal condition due to specific manufacturing processes for engineer- ing-scale components. The available data for these three types of treatments were assessed and mini- mum tensile properties were determined based on recommendation of Structural Design Criteria for the ITER In-vessel Components. The available data for these heat treatments were analyzed for assess- ment of neutron irradiation effect. Using the definitions of the ITER Structural Design Criteria the design allowable stress intensity values are proposed for CuCrZr alloy after various heat treatments.

  14. iRadMat: A thermo-mechanical testing system for in situ high-energy X-ray characterization of radioactive specimens

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Xu, Chi; Wang, Leyun; Chen, Yiren; Li, Meimei; Almer, Jonathan D.; Benda, Erika; Kenesei, Peter; Mashayekhi, Ali; Park, Jun-Sang; Westferro, Frank J.

    2017-01-01

    We present an in situ Radiated Materials (iRadMat) experimental module designed to interface with a servo-hydraulic load frame for X-ray measurements at beamline 1-ID at the Advanced Photon Source. This new capability allows in situ studies of radioactive specimens subject to thermo-mechanical loading using a suite of high-energy X-ray scattering and imaging techniques. The iRadMat is a radiation-shielded vacuum heating system with the sample rotation-under-load capability. We describe the design features and performances of the iRadMat and present a dataset from a 300 °C uniaxial tensile test of a neutron-irradiated pure Fe specimen to demonstrate its capabilities.

  15. Effect of microstructure on the coupled electromagnetic-thermo-mechanical response of cyclotrimethylenetrinitramine-estane energetic aggregates to infrared laser radiation

    SciTech Connect

    Brown, Judith A.; Zikry, M. A.

    2015-09-28

    The coupled electromagnetic (EM)-thermo-mechanical response of cyclotrimethylenetrinitramine-estane energetic aggregates under laser irradiation and high strain rate loads has been investigated for various aggregate sizes and binder volume fractions. The cyclotrimethylenetrinitramine (RDX) crystals are modeled with a dislocation density-based crystalline plasticity formulation and the estane binder is modeled with finite viscoelasticity through a nonlinear finite element approach that couples EM wave propagation with laser heat absorption, thermal conduction, and inelastic deformation. Material property and local behavior mismatch at the crystal-binder interfaces resulted in geometric scattering of the EM wave, electric field and laser heating localization, high stress gradients, dislocation density, and crystalline shear slip accumulation. Viscous sliding in the binder was another energy dissipation mechanism that reduced stresses in aggregates with thicker binder ligaments and larger binder volume fractions. This investigation indicates the complex interactions between EM waves and mechanical behavior, for accurate predictions of laser irradiation of heterogeneous materials.

  16. Space power subsystem automation technology

    NASA Technical Reports Server (NTRS)

    Graves, J. R. (Compiler)

    1982-01-01

    The technology issues involved in power subsystem automation and the reasonable objectives to be sought in such a program were discussed. The complexities, uncertainties, and alternatives of power subsystem automation, along with the advantages from both an economic and a technological perspective were considered. Whereas most spacecraft power subsystems now use certain automated functions, the idea of complete autonomy for long periods of time is almost inconceivable. Thus, it seems prudent that the technology program for power subsystem automation be based upon a growth scenario which should provide a structured framework of deliberate steps to enable the evolution of space power subsystems from the current practice of limited autonomy to a greater use of automation with each step being justified on a cost/benefit basis. Each accomplishment should move toward the objectives of decreased requirement for ground control, increased system reliability through onboard management, and ultimately lower energy cost through longer life systems that require fewer resources to operate and maintain. This approach seems well-suited to the evolution of more sophisticated algorithms and eventually perhaps even the use of some sort of artificial intelligence. Multi-hundred kilowatt systems of the future will probably require an advanced level of autonomy if they are to be affordable and manageable.

  17. Transformation behavior and shape memory characteristics of thermo-mechanically treated Ti–(45−x)Ni–5Cu–xV (at%) alloys

    SciTech Connect

    Jang, Jae-young; Chun, Su-jin; Choi, Eunsoo; Liu, Yinong; Yang, Hong; Nam, Tae-hyun

    2012-10-15

    Transformation behavior, shape memory characteristics and superelasticity of thermo-mechanically treated Ti–(45−x)Ni–5Cu–xV (at%) (x = 0.5–2.0) alloys were investigated by means of differential scanning calorimetry, transmission electron microscopy, X-ray diffractions, thermal cycling tests under constant load and tensile tests. The B2–B19′ transformation occurred when V content was 0.5 at%, above which the B2–B19–B19′ transformation occurred. The B2–B19 transformation was not separated clearly from the B19–B19′ transformation. Thermo-mechanically treated Ti–(45−x)Ni–5Cu–xV alloys showed perfect shape memory effect and transformation hysteresis(ΔT) of Ti–43.5Ni–5.0Cu–1.5V and Ti–43.0Ni–5.0Cu–2.0V alloys was about 9 K which was much smaller than that of a Ti–44.5Ni–5.0Cu–0.5V alloy(23.3 K). More than 90% of superelastic recovery ratio was observed in all specimens and transformation hysteresis (Δσ) of a Ti–44.5Ni–5.0Cu–0.5V alloy was about 70 MPa, which was much larger than that of a Ti–43.0Ni–5.0Cu–2.0V alloy (35 MPa).

  18. The Atmosphere Explorer power subsystem

    NASA Technical Reports Server (NTRS)

    Obenschain, A.; Bacher, J.; Callen, P.

    1974-01-01

    The present work describes the design and in-flight performance of the power subsystem for the first three Atmosphere Explorer (AE) spacecraft. The subsystem provides all electrical power to the spacecraft loads and consists of a solar array, three batteries, and a power supply electronics unit. Power from the solar array is supplied to the spacecraft loads through an unregulated power bus, which varies between -26 and -38 V. Loads which are normally on only during data collection phases of an orbit are fed from a tightly regulated -24.5 V bus. Power subsystem performance during the first three months in orbit has been nominal, except for an anomally in the shunt limiter protection circuitry. A malfunctioning shunt control amplifier was reconnected via ground command.

  19. The Atmosphere Explorer power subsystem

    NASA Technical Reports Server (NTRS)

    Obenschain, A.; Bacher, J.; Callen, P.

    1974-01-01

    The design and operation of the power subsystem for the Atmospheric Explorer spacecraft are discussed. The additional functional redundancy which was added in several component areas to improve the overall subsystem reliability is analyzed. The battery charging technique has been modified to include third electrode overcharge control. The automatic removal of all battery charge is provided to correct abnormally high battery voltages. An undervoltage detector has been added which removes all nonessential spacecraft loads when the battery voltage falls below a given level. All automatic functions can be over-ridden by ground command.

  20. Spacelab data management subsystem phase B study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The Spacelab data management system is described. The data management subsystem (DMS) integrates the avionics equipment into an operational system by providing the computations, logic, signal flow, and interfaces needed to effectively command, control, monitor, and check out the experiment and subsystem hardware. Also, the DMS collects/retrieves experiment data and other information by recording and by command of the data relay link to ground. The major elements of the DMS are the computer subsystem, data acquisition and distribution subsystem, controls and display subsystem, onboard checkout subsystem, and software. The results of the DMS portion of the Spacelab Phase B Concept Definition Study are analyzed.

  1. Marginal and internal fit of heat pressed versus CAD/CAM fabricated all-ceramic onlays after exposure to thermo-mechanical fatigue

    PubMed Central

    Guess, Petra C.; Vagopoulou, Thaleia; Zhang, Yu; Wolkewitz, Martin; Strub, Joerg R.

    2015-01-01

    Objectives The aim of the study was to evaluate the marginal and internal fit of heat-pressed and CAD/CAM fabricated all-ceramic onlays before and after luting as well as after thermo-mechanical fatigue. Materials and Methods Seventy-two caries-free, extracted human mandibular molars were randomly divided into three groups (n=24/group). All teeth received an onlay preparation with a mesio-occlusal-distal inlay cavity and an occlusal reduction of all cusps. Teeth were restored with heat-pressed IPS-e.max-Press* (IP, *Ivoclar-Vivadent) and Vita-PM9 (VP, Vita-Zahnfabrik) as well as CAD/CAM fabricated IPS-e.max-CAD* (IC, Cerec 3D/InLab/Sirona) all-ceramic materials. After cementation with a dual-polymerizing resin cement (VariolinkII*), all restorations were subjected to mouth-motion fatigue (98N, 1.2 million cycles; 5°C/55°C). Marginal fit discrepancies were examined on epoxy replicas before and after luting as well as after fatigue at 200x magnification. Internal fit was evaluated by multiple sectioning technique. For the statistical analysis, a linear model was fitted with accounting for repeated measurements. Results Adhesive cementation of onlays resulted in significantly increased marginal gap values in all groups, whereas thermo-mechanical fatigue had no effect. Marginal gap values of all test groups were equal after fatigue exposure. Internal discrepancies of CAD/CAM fabricated restorations were significantly higher than both press manufactured onlays. Conclusions Mean marginal gap values of the investigated onlays before and after luting as well as after fatigue were within the clinically acceptable range. Marginal fit was not affected by the investigated heat-press versus CAD/CAM fabrication technique. Press fabrication resulted in a superior internal fit of onlays as compared to the CAD/CAM technique. Clinical Relevance Clinical requirements of 100 μm for marginal fit were fulfilled by the heat-press as well as by the CAD/CAM fabricated all-ceramic onlays

  2. Catalytic distillation water recovery subsystem

    NASA Technical Reports Server (NTRS)

    Budininkas, P.; Rasouli, F.

    1985-01-01

    An integrated engineering breadboard subsystem for the recovery of potable water from untreated urine based on the vapor phase catalytic ammonia removal was designed, fabricated and tested. Unlike other evaporative methods, this process catalytically oxidizes ammonia and volatile hydrocarbons vaporizing with water to innocuous products; therefore, no pretreatment of urine is required. Since the subsystem is fabricated from commercially available components, its volume, weight and power requirements are not optimized; however, it is suitable for zero-g operation. The testing program consists of parametric tests, one month of daily tests and a continuous test of 168 hours duration. The recovered water is clear, odorless, low in ammonia and organic carbon, and requires only an adjustment of its pH to meet potable water standards. The obtained data indicate that the vapor phase catalytic ammonia removal process, if further developed, would also be competitive with other water recovery systems in weight, volume and power requirements.

  3. Life support subsystem monitoring instrumentation

    NASA Technical Reports Server (NTRS)

    Powell, J. D.; Kostell, G. D.

    1974-01-01

    The recognition of the need for instrumentation in manned spacecraft life-support subsystems has increased significantly over the past several years. Of the required control and monitoring instrumentation, this paper will focus on the monitoring instrumentation as applied to life-support subsystems. The initial approach used independent sensors, independent sensor signal conditioning circuitry, and independent logic circuitry to provide shutdown protection only. This monitoring system was replaced with a coordinated series of printed circuit cards, each of which contains all the electronics to service one sensor and provide performance trend information, fault detection and isolation information, and shutdown protection. Finally, a review of sensor and instrumentation problems is presented, and the requirement for sensors with built-in signal conditioning and provisions for in situ calibration is discussed.

  4. NFIRAOS beamsplitters subsystems optomechanical design

    NASA Astrophysics Data System (ADS)

    Lamontagne, Frédéric; Desnoyers, Nichola; Nash, Reston; Boucher, Marc-André; Martin, Olivier; Buteau-Vaillancourt, Louis; Châteauneuf, François; Atwood, Jenny; Hill, Alexis; Byrnes, Peter W. G.; Herriot, Glen; Véran, Jean-Pierre

    2016-07-01

    The early-light facility adaptive optics system for the Thirty Meter Telescope (TMT) is the Narrow-Field InfraRed Adaptive Optics System (NFIRAOS). The science beam splitter changer mechanism and the visible light beam splitter are subsystems of NFIRAOS. This paper presents the opto-mechanical design of the NFIRAOS beam splitters subsystems (NBS). In addition to the modal and the structural analyses, the beam splitters surface deformations are computed considering the environmental constraints during operation. Surface deformations are fit to Zernike polynomials using SigFit software. Rigid body motion as well as residual RMS and peak-to-valley surface deformations are calculated. Finally, deformed surfaces are exported to Zemax to evaluate the transmitted and reflected wave front error. The simulation results of this integrated opto-mechanical analysis have shown compliance with all optical requirements.

  5. The Human Subsystem - Definition and Integration

    NASA Technical Reports Server (NTRS)

    vonBengston, Kristian; Twyford, Evan

    2007-01-01

    This paper will discuss the use of the human subsystem in development phases of human space flight. Any space mission has clearly defined subsystems, managed by experts attached to these. Clearly defined subsystems and correct use provide easier and more efficient development for each independent subsystem and for the relation between these subsystems. Furthermore, this paper will argue that a defined subsystem related to humans in space has not always been clearly present, and that correct implementation is perhaps missing, based on experience and survey data. Finally, the authors will discuss why the human subsystem has not been fully integrated, why it must be a mandatory part of the programming, a re-definition of the human subsystem, and suggestions of methods to improve the integration of human factors in the development.

  6. Holonomic Quantum Computation in Subsystems

    NASA Astrophysics Data System (ADS)

    Oreshkov, Ognyan

    2009-08-01

    We introduce a generalized method of holonomic quantum computation (HQC) based on encoding in subsystems. As an application, we propose a scheme for applying holonomic gates to unencoded qubits by the use of a noisy ancillary qubit. This scheme does not require initialization in a subspace since all dynamical effects factor out as a transformation on the ancilla. We use this approach to show how fault-tolerant HQC can be realized via 2-local Hamiltonians with perturbative gadgets.

  7. A thermo-mechanical correlation with driving forces for hcp martensite and twin formations in the Fe–Mn–C system exhibiting multicomposition sets

    DOE PAGES

    Nakano, Jinichiro

    2013-03-15

    Thermodynamic properties of the Fe-Mn-C system were investigated by using an analytical model constructed by a CALPHAD approach. Stacking fault energy (SFE) of the fcc structure with respect to the hcp phase was always constant at T0, independent of composition and temperature when the other related parameters were assumed to be constant. Experimental limits for the thermal hcp formation and the mechanical (deformation-induced) hcp formation were separated by the SFE at T0. The driving force for the fcc to hcp transition, defined as a dimensionless value –dGm/(RT), was determined in the presence of Fe-rich and Mn-rich composition sets in eachmore » phase. Carbon tended to partition to the Mn-rich phase rather than to the Fe-rich phase for the studied compositions. The obtained results revealed a thermo-mechanical correlation with empirical yield strength, maximum true stress and maximum true strain. The proportionality between thermodynamics and mechanical properties is discussed.« less

  8. A thermo-mechanical correlation with driving forces for hcp martensite and twin formations in the Fe-Mn-C system exhibiting multicomposition sets.

    PubMed

    Nakano, Jinichiro

    2013-02-01

    The thermodynamic properties of the Fe-Mn-C system were investigated by using an analytical model constructed by a CALPHAD approach. The stacking fault energy (SFE) of the fcc structure with respect to the hcp phase was always constant at T0, independent of the composition and temperature when other related parameters were assumed to be constant. Experimental limits for the thermal hcp formation and the mechanical (deformation-induced) hcp formation were separated by the SFE at T0. The driving force for the fcc to hcp transition, defined as a dimensionless value -dGm/(RT), was determined in the presence of Fe-rich and Mn-rich composition sets in each phase. Carbon tended to partition to the Mn-rich phase rather than to the Fe-rich phase for the compositions studied. The results obtained revealed a thermo-mechanical correlation with empirical yield strength, maximum true stress and maximum true strain. The proportionality between thermodynamics and mechanical properties is discussed.

  9. A thermo-mechanical correlation with driving forces for hcp martensite and twin formations in the Fe–Mn–C system exhibiting multicomposition sets

    SciTech Connect

    Nakano, Jinichiro

    2013-03-15

    Thermodynamic properties of the Fe-Mn-C system were investigated by using an analytical model constructed by a CALPHAD approach. Stacking fault energy (SFE) of the fcc structure with respect to the hcp phase was always constant at T0, independent of composition and temperature when the other related parameters were assumed to be constant. Experimental limits for the thermal hcp formation and the mechanical (deformation-induced) hcp formation were separated by the SFE at T0. The driving force for the fcc to hcp transition, defined as a dimensionless value –dGm/(RT), was determined in the presence of Fe-rich and Mn-rich composition sets in each phase. Carbon tended to partition to the Mn-rich phase rather than to the Fe-rich phase for the studied compositions. The obtained results revealed a thermo-mechanical correlation with empirical yield strength, maximum true stress and maximum true strain. The proportionality between thermodynamics and mechanical properties is discussed.

  10. A macroscopic multi-mechanism based constitutive model for the thermo-mechanical cyclic degeneration of shape memory effect of NiTi shape memory alloy

    NASA Astrophysics Data System (ADS)

    Yu, Chao; Kang, Guozheng; Kan, Qianhua

    2017-01-01

    A macroscopic based multi-mechanism constitutive model is constructed in the framework of irreversible thermodynamics to describe the degeneration of shape memory effect occurring in the thermo-mechanical cyclic deformation of NiTi shape memory alloys (SMAs). Three phases, austenite A, twinned martensite Mt and detwinned martensite Md , as well as the phase transitions occurring between each pair of phases (A→ M t , Mt→ A , A→ M d , Md→ A , and Mt→ M d) are considered in the proposed model. Meanwhile, two kinds of inelastic deformation mechanisms, martensite transformation-induced plasticity and reorientation-induced plasticity, are used to explain the degeneration of shape memory effects of NiTi SMAs. The evolution equations of internal variables are proposed by attributing the degeneration of shape memory effect to the interaction between the three phases (A, Mt , and Md) and plastic deformation. Finally, the capability of the proposed model is verified by comparing the predictions with the experimental results of NiTi SMAs. It is shown that the degeneration of shape memory effect and its dependence on the loading level can be reasonably described by the proposed model.

  11. Investigation of the thermo-mechanical behavior of neutron-irradiated Fe-Cr alloys by self-consistent plasticity theory

    NASA Astrophysics Data System (ADS)

    Xiao, Xiazi; Terentyev, Dmitry; Yu, Long; Bakaev, A.; Jin, Zhaohui; Duan, Huiling

    2016-08-01

    The thermo-mechanical behavior of non-irradiated (at 223 K, 302 K and 573 K) and neutron irradiated (at 573 K) Fe-2.5Cr, Fe-5Cr and Fe-9Cr alloys is studied by a self-consistent plasticity theory, which consists of constitutive equations describing the contribution of radiation defects at grain level, and the elastic-viscoplastic self-consistent method to obtain polycrystalline behaviors. Attention is paid to two types of radiation-induced defects: interstitial dislocation loops and solute rich clusters, which are believed to be the main sources of hardening in Fe-Cr alloys at medium irradiation doses. Both the hardening mechanism and microstructural evolution are investigated by using available experimental data on microstructures, and implementing hardening rules derived from atomistic data. Good agreement with experimental data is achieved for both the yield stress and strain hardening of non-irradiated and irradiated Fe-Cr alloys by treating dislocation loops as strong thermally activated obstacles and solute rich clusters as weak shearable ones.

  12. Determination of the thermo-mechanical properties in starch and starch/gluten systems at low moisture content - a comparison of DSC and TMA.

    PubMed

    Homer, Stephen; Kelly, Michael; Day, Li

    2014-08-08

    The impact of heating rate on the glass transition (Tg) and melting transitions observed by differential scanning calorimetry (DSC) on starch and a starch/gluten blend (80:20 ratio) at low moisture content was examined. The results were compared to those determined by thermo-mechanical analysis (TMA). Comparison with dynamic mechanical thermal analysis (DMTA) and phase transition analysis (PTA) is also discussed. Higher heating rates increased the determined Tg as well as the melting peak temperatures in both starch and the starch/gluten blend. A heating rate of 5°C/min gave the most precise value of Tg while still being clearly observed above the baseline. Tg values determined from the first and second DSC scans were found to differ significantly and retrogradation of starch biopolymers may be responsible. Tg values of starch determined by TMA showed good agreement with DSC results where the Tg was below 80°C. However, moisture loss led to inaccurate Tg determination for TMA analyses at temperatures above 80°C.

  13. High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter

    SciTech Connect

    De Muri, M. Pasqualotto, R.; Dalla Palma, M.; Cervaro, V.; Fasolo, D.; Franchin, L.; Tollin, M.; Serianni, G.; Cavallin, T.; Greuner, H.; Böswirth, B.

    2014-02-15

    Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

  14. Thermo-Mechanical Modeling of Seismic Cycle and Quaternary Deformation of the Asal Rift, Djibouti, Africa: Implication for the Rheology of the Lithosphere

    NASA Astrophysics Data System (ADS)

    Cattin, R.; de Chabalier, J.; King, G.; Vigny, C.; Avouac, J.; Ruegg, J.

    2001-12-01

    Because it is subaerial, the Asal rift in the Afar depression of Djibouti provides an exceptional opportunity to study the mechanics of active rifting. Horizontal extension and vertical displacements have been deduced from the deformation of ~ 100,000 yr old volcano that had formed across the rift zone. Over the three last decades seismic, geodetic and field observations have been performed in this region. Over this period major seismovolcanic crisis occurred in 1978. This unique set of data provides information on long term, co-seismic, post-seismic and inter-seismic deformation that might be used to infer the mechanical properties of the rift zone. In that respect the data are compared with the results of a thermo-mechanical modeling. We compute the thermal structure and deformation separately. The temperature field, computed from a finite difference scheme of heat conduction in a moving medium, is adjusted to fit data of 6 thermal wells. Deformation is computed from a two-dimensional finite element model (ADELI) that was modified for the purpose of this study. We conducted several sets of experiments, varying rheological parameters and boundary conditions, in which a section of lithosphere is submitted to 17-20 mm/yr horizontal spreading. Our modeling reconciles all data on seismic cycle and quaternary deformation. The following questions will be tackle: what is the range of viscosity associated with ductile flow in lithosphere? What is the effect of plasticity? What is the contribution of tectonics and volcanism to rifting processes?

  15. Laccase-Catalyzed Surface Modification of Thermo-Mechanical Pulp (TMP) for the Production of Wood Fiber Insulation Boards Using Industrial Process Water

    PubMed Central

    Schubert, Mark; Ruedin, Pascal; Civardi, Chiara; Richter, Michael; Hach, André; Christen, Herbert

    2015-01-01

    Low-density wood fiber insulation boards are traditionally manufactured in a wet process using a closed water circuit (process water). The water of these industrial processes contains natural phenolic extractives, aside from small amounts of admixtures (e.g., binders and paraffin). The suitability of two fungal laccases and one bacterial laccase was determined by biochemical characterization considering stability and substrate spectra. In a series of laboratory scale experiments, the selected commercial laccase from Myceliophtora thermophila was used to catalyze the surface modification of thermo-mechanical pulp (TMP) using process water. The laccase catalyzed the covalent binding of the phenolic compounds of the process water onto the wood fiber surface and led to change of the surface chemistry directly via crosslinking of lignin moieties. Although a complete substitution of the binder was not accomplished by laccase, the combined use of laccase and latex significantly improved the mechanical strength properties of wood fiber boards. The enzymatically-treated TMP showed better interactions with the synthetic binder, as shown by FTIR-analysis. Moreover, the enzyme is extensively stable in the process water and the approach requires no fresh water as well as no cost-intensive mediator. By applying a second-order polynomial model in combination with the genetic algorithm (GA), the required amount of laccase and synthetic latex could be optimized enabling the reduction of the binder by 40%. PMID:26046652

  16. High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter.

    PubMed

    De Muri, M; Cavallin, T; Pasqualotto, R; Dalla Palma, M; Cervaro, V; Fasolo, D; Franchin, L; Tollin, M; Greuner, H; Böswirth, B; Serianni, G

    2014-02-01

    Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

  17. A semi analytical method for electro-thermo-mechanical nonlinear vibration analysis of nanobeam resting on the Winkler-Pasternak foundations with general elastic boundary conditions

    NASA Astrophysics Data System (ADS)

    Zarepour, Misagh; Amirhosein Hosseini, Seyed

    2016-08-01

    This study presents an examination of nonlinear free vibration of a nanobeam under electro-thermo-mechanical loading with elastic medium and various boundary conditions, especially the elastic boundary condition. The nanobeam is modeled as an Euler-Bernoulli beam. The von Kármán strain-displacement relationship together with Hamilton’s principle and Eringen’s theory are employed to derive equations of motion. The nonlinear free vibration frequency is obtained for simply supported (S-S) and elastic supported (E-E) boundary conditions. E-E boundary condition is a general and actual form of boundary conditions and it is chosen because of more realistic behavior. By applying the differential transform method (DTM), the nanobeam’s natural frequencies can be easily obtained for the two different boundary conditions mentioned above. Performing a precise study led to investigation of the influences of nonlocal parameter, temperature change, spring constants (either for elastic medium or boundary condition) and imposed electric potential on the nonlinear free vibration characteristics of nanobeam. The results for S-S and E-E nanobeams are compared with each other. In order to validate the results, some comparisons are presented between DTM results and open literature to show the accuracy of this new approach. It has been discovered that DTM solves the equations with minimum calculation cost.

  18. A thermo-mechanical correlation with driving forces for hcp martensite and twin formations in the Fe–Mn–C system exhibiting multicomposition sets

    PubMed Central

    Nakano, Jinichiro

    2013-01-01

    The thermodynamic properties of the Fe–Mn–C system were investigated by using an analytical model constructed by a CALPHAD approach. The stacking fault energy (SFE) of the fcc structure with respect to the hcp phase was always constant at T0, independent of the composition and temperature when other related parameters were assumed to be constant. Experimental limits for the thermal hcp formation and the mechanical (deformation-induced) hcp formation were separated by the SFE at T0. The driving force for the fcc to hcp transition, defined as a dimensionless value –dGm/(RT), was determined in the presence of Fe-rich and Mn-rich composition sets in each phase. Carbon tended to partition to the Mn-rich phase rather than to the Fe-rich phase for the compositions studied. The results obtained revealed a thermo-mechanical correlation with empirical yield strength, maximum true stress and maximum true strain. The proportionality between thermodynamics and mechanical properties is discussed. PMID:27877555

  19. Influence of gallium and alkali halide addition on the optical and thermo mechanical properties of GeSe2-Ga2Se3 glass

    NASA Astrophysics Data System (ADS)

    Volk, Y. V.; Malyarevich, A. M.; Yumashev, K. V.; Matrosov, V. N.; Matrosova, T. A.; Kupchenko, M. I.

    2007-10-01

    A systematic compositional study of a new family of chalcogenide glasses, transparent from the visible range up to 16 μm has been performed. Numerous glass forming regions were explored in the GeSe2-Ga2Se3-MX system (MX = alkali halide) in order to understand the role of alkali halides and the effect of Ga substitution for Sb in the glass structure. To that avail, several ternary diagrams were investigated, and optical and thermo-mechanical measurements were performed. It is shown that the introduction of an alkali halide in the GeSe2-Ga2Se3 glasses increased the band-gap energy Eg by stabilizing electrons from the lone pairs of selenium. However, the glass hardness was lowered due to a decrease in the glass network reticulation. The chemical resistance was studied in a glass containing high CsCl content. Significant corrosion occurred when the glass was exposed to hot water for several hours. There is a great deal of interest in these glasses for use in thermal imaging devices, as they permit the alignment of infrared optical systems with visible red light. Furthermore, the low cost of raw materials and the possibility of shaping these glasses into lenses by molding could extend their utilization from defense to civilian applications.

  20. Influence of gallium and alkali halide addition on the optical and thermo-mechanical properties of GeSe2-Ga2Se3 glass

    NASA Astrophysics Data System (ADS)

    Calvez, L.; Lucas, P.; Rozé, M.; Ma, H. L.; Lucas, J.; Zhang, X. H.

    2007-10-01

    A systematic compositional study of a new family of chalcogenide glasses, transparent from the visible range up to 16 μm has been performed. Numerous glass forming regions were explored in the GeSe2-Ga2Se3-MX system (MX = alkali halide) in order to understand the role of alkali halides and the effect of Ga substitution for Sb in the glass structure. To that avail, several ternary diagrams were investigated, and optical and thermo-mechanical measurements were performed. It is shown that the introduction of an alkali halide in the GeSe2-Ga2Se3 glasses increased the band-gap energy Eg by stabilizing electrons from the lone pairs of selenium. However, the glass hardness was lowered due to a decrease in the glass network reticulation. The chemical resistance was studied in a glass containing high CsCl content. Significant corrosion occurred when the glass was exposed to hot water for several hours. There is a great deal of interest in these glasses for use in thermal imaging devices, as they permit the alignment of infrared optical systems with visible red light. Furthermore, the low cost of raw materials and the possibility of shaping these glasses into lenses by molding could extend their utilization from defense to civilian applications.

  1. High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter

    NASA Astrophysics Data System (ADS)

    De Muri, M.; Cavallin, T.; Pasqualotto, R.; Dalla Palma, M.; Cervaro, V.; Fasolo, D.; Franchin, L.; Tollin, M.; Greuner, H.; Böswirth, B.; Serianni, G.

    2014-02-01

    Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

  2. Laccase-Catalyzed Surface Modification of Thermo-Mechanical Pulp (TMP) for the Production of Wood Fiber Insulation Boards Using Industrial Process Water.

    PubMed

    Schubert, Mark; Ruedin, Pascal; Civardi, Chiara; Richter, Michael; Hach, André; Christen, Herbert

    2015-01-01

    Low-density wood fiber insulation boards are traditionally manufactured in a wet process using a closed water circuit (process water). The water of these industrial processes contains natural phenolic extractives, aside from small amounts of admixtures (e.g., binders and paraffin). The suitability of two fungal laccases and one bacterial laccase was determined by biochemical characterization considering stability and substrate spectra. In a series of laboratory scale experiments, the selected commercial laccase from Myceliophtora thermophila was used to catalyze the surface modification of thermo-mechanical pulp (TMP) using process water. The laccase catalyzed the covalent binding of the phenolic compounds of the process water onto the wood fiber surface and led to change of the surface chemistry directly via crosslinking of lignin moieties. Although a complete substitution of the binder was not accomplished by laccase, the combined use of laccase and latex significantly improved the mechanical strength properties of wood fiber boards. The enzymatically-treated TMP showed better interactions with the synthetic binder, as shown by FTIR-analysis. Moreover, the enzyme is extensively stable in the process water and the approach requires no fresh water as well as no cost-intensive mediator. By applying a second-order polynomial model in combination with the genetic algorithm (GA), the required amount of laccase and synthetic latex could be optimized enabling the reduction of the binder by 40%.

  3. Technology advancement of an oxygen generation subsystem

    NASA Technical Reports Server (NTRS)

    Lee, M. K.; Burke, K. A.; Schubert, F. H.; Wynveen, R. A.

    1979-01-01

    An oxygen generation subsystem based on water electrolysis was developed and tested to further advance the concept and technology of the spacecraft air revitalization system. Emphasis was placed on demonstrating the subsystem integration concept and hardware maturity at a subsystem level. The integration concept of the air revitalization system was found to be feasible. Hardware and technology of the oxygen generation subsystem was demonstrated to be close to the preprototype level. Continued development of the oxygen generation technology is recommended to further reduce the total weight penalties of the oxygen generation subsystem through optimization.

  4. FLPP NGL Structural Subsystems Activity

    NASA Astrophysics Data System (ADS)

    Jaredson, D.; Ramusat, G.; Appel, S.; Cardone, T.; Persson, J.; Baiocco, P.; Lavelle, F.; Bouilly, Th.

    2012-07-01

    The ESA Future Launchers Preparatory Programme (FLPP) is the basis for new paradigms, investigating the key elements, logic and roadmaps to prepare the development of the safe, reliable and low cost next European Launch Vehicle (LV) for access to space (dubbed NGL - Next Generation LV), with an initial operational capability mid-next decade. In addition to carry cargo to conventional GTO or SSO, the European NGL has to be flexible enough to cope with new pioneering institutional missions as well as the evolving commercial payloads market. This achievement is broached studying three main areas relevant to ELVs: System concepts, Propulsion and Core Technology During the preliminary design activity, a number of design alternatives concerning NGL main structural subsystems have been investigated. Technology is one of the ways to meet the NGL challenges to either improve the performances or to reduce the cost or both. The relevant requirements allow to steer a ‘top-down’ approach for their conception and to propose the most effective technologies. Furthermore, all these technology developments represent a significant ‘bottom-up’ approach investment and concern a large range of activities. The structural subsystems portfolio of the FLPP ‘Core Technology’ activity encompasses major cutting-edge challenges for maturation of the various subsystems leading to reduce overall structural mass, increasing structural margins for robustness, metallic and composite containment of cryogenic propellants, significantly reducing fabrication and operations cost, etc. to derive performing upper and booster stages. Application of concurrent engineering methods will allow developments of performing technology demonstrators in terms of need, demonstration objective, size and cost yielding to safe, low-risk technical approaches for a future development. Potential ability of these advanced structural LV technologies to satisfy the system requirements of the NGL and their current

  5. iPAS Propulsion Subsystem

    NASA Technical Reports Server (NTRS)

    Sanchez, Rodrigo

    2011-01-01

    The ultimate goal of the Integrated Power, Avionics and Software (iPAS) project is to develop a simulation facility that can be apply to various missions that use common avionics, hardware, and software architecture. The iPAS facility will model several subsystems, the EP4 contribution to the project is to design and build a low fidelity representation of the in-space propulsion system for the iPAS simulation. The system would use a pressurized bottle to provide the gas for the thrusters. Air will be used to perform the simulation to prevent a hazardous environment in the facility. Three cold gas thrusters previously used for the X-38 program will be used for the simulation because they are on hand and available for use. An incremental design-build-test approach will be taken where the X-38 thrusters may be replaced with actual flight thrusters as the flight design is matured. A pressurized system must be designed, built, and tested to reduce the 2,400psi bottle pressure to a reasonable pressure (0-800psig) to minimize the amount of noise created upon thruster activation. Once all the subsystems are completed they will be integrated together for testing.

  6. Preprototype independent air revitalization subsystem

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Hallick, T. M.; Woods, R. R.

    1982-01-01

    The performance and maturity of a preprototype, three-person capacity, automatically controlled and monitored, self-contained independent air revitalization subsystem were evaluated. The subsystem maintains the cabin partial pressure of oxygen at 22 kPa (3.2 psia) and that of carbon dioxide at 400 Pa (3 mm Hg) over a wide range of cabin air relative humidity conditions. Consumption of water vapor by the water vapor electrolysis module also provides partial humidity control of the cabin environment. During operation, the average carbon dioxide removal efficiency at baseline conditions remained constant throughout the test at 84%. The average electrochemical depolarized concentrator cell voltage at the end of the parametric/endurance test was 0.41 V, representing a very slowly decreasing average cell voltage. The average water vapor electrolysis cell voltage increased only at a rate of 20 mu/h from the initial level of 1.67 V to the final level of 1.69 V at conclusion of the testing.

  7. Microstructures and High-Temperature Mechanical Properties of a Martensitic Heat-Resistant Stainless Steel 403Nb Processed by Thermo-Mechanical Treatment

    NASA Astrophysics Data System (ADS)

    Chen, Liqing; Zeng, Zhouyu; Zhao, Yang; Zhu, Fuxian; Liu, Xianghua

    2013-11-01

    Thermo-mechanical treatments (TMT) at different rolling deformation temperatures were utilized to process a martensitic heat-resistant stainless steel 403Nb containing 12 wt pct Cr and small additions of Nb and V. Microstructures and mechanical properties at room and elevated temperatures were characterized by scanning electron microscopy, transmission electron microscopy, and hardness, tensile, and creep tests. The results showed that high-temperature mechanical behavior after TMT can be greatly improved and microstructures with refined martensitic lath and finely dispersed nanosized MX carbides could be produced. The particle sizes of M23C6 and MX carbides in 403Nb steel after conventional normalizing and tempering (NT) treatments are about 50 to 160 and 10 to 20 nm, respectively, while those after TMT at 1123 K (850 °C) and subsequent tempering at 923 K (650 °C) for 2 hours reach about 25 to 85 and 5 to 10 nm, respectively. Under the condition of 260 MPa and 873 K (600 °C), the tensile creep rupture life of 403Nb steel after TMT at 1123 K (850 °C) is 455 hours, more than 3 times that after conventional NT processes. The mechanisms for improving mechanical properties at elevated temperature were analyzed in association with the existence of finely dispersed nanosized MX particles within martensitic lath. It is the nanosized MX particles having the higher stability at elevated temperature that assist both dislocation hardening and sub-grain hardening for longer duration by pinning the movement of dislocations and sub-grain boundary migration.

  8. Thermal, Mechanical and Thermo-Mechanical Assessment of the Rock Mass Surrounding SKB's Prototype Repository at Äspö HRL

    NASA Astrophysics Data System (ADS)

    Lönnqvist, Margareta; Hökmark, Harald

    2016-04-01

    The Prototype Repository (PR) was a field test of six, electrically heated, full-scale waste containers resembling the key component of a KBS-3 nuclear waste repository. The design and heat load was similar to the proposed repository at Forsmark, Sweden. In this paper, the thermal, mechanical and thermo-mechanical response of the PR host rock to excavation and to the subsequent heating is assessed. The assessment is carried out using three-dimensional models (numerical and analytical) in combination with monitoring data and visual observations from the excavations. Certain measurements and observations agree well with results from the models. These include temperature measurements during the heating phase. Additional measurements include patterns of low-magnitude acoustic emission events around the deposition holes tracked during the excavation. The spatial distribution of these events coincide with regions of modelled high compressive stresses. Models with a simple fracture network, consisting of planar disks with laboratory-scale properties, appear to give upper bound estimates of the stress disturbances caused by a real fracture network. The magnitude of the modelled stresses around the deposition hole is typically below the spalling strength. The lack of any significant or systematic occurrence of spalling in the deposition hole walls supports the modelling results. Several instruments installed at different positions to monitor stress change, strain and deformation malfunctioned during the nearly 8-year-long monitoring period. Despite this, there is ample evidence to support the overall conclusion that the modelling results and observations are in sufficient agreement to strengthen the confidence in the modelling approach.

  9. Matrix structure evolution and thermo-mechanical properties of carbon fiber-reinforced Al{sub 2}O{sub 3}-SiC-C castable composites

    SciTech Connect

    Li, Xiangcheng Li, Yaxiong; Chen, Liufang; Zhu, Boquan

    2015-01-15

    Highlights: • Carbon fibers are formed in Al{sub 2}O{sub 3}-SiC-C castable composites under the action of nano Ni. • Starting growth temperature is 900 °C and growth mechanism agrees with V–S model. • The high temperature strength of composites can be increased by above 40%. • The thermal shock resistance can be enhanced by above 20%. - Abstract: The spalling and corrosion during the thermal cycles are the main causes of the damages observed in Al{sub 2}O{sub 3}-SiC-C castable composites that are used in molten-iron system. Using the catalyst of nano Ni and ball pitch in the matrix, Al{sub 2}O{sub 3}-SiC-C castable composites were prepared with the anti-oxidant addition of silicon. The results indicate that the high temperature of the Al{sub 2}O{sub 3}-SiC-C castable composites can be increased by above 42%, and the thermal shock resistance can be enhanced by above 20% because the ball pitch is carbonized and releases C{sub x}H{sub y} vapor, which can be pyrolized to carbon atoms and subsequently deposited into carbon fibers under the catalyst action. The starting temperature of carbon fiber growth is approximately 900 °C, and their diameter and aspect ratio can increase with the rising temperature. The in-situ generation of carbon fibers in Al{sub 2}O{sub 3}-SiC-C castable composites can significantly improve the fibers’ thermo-mechanical properties.

  10. Cassini Mission Sequence Subsystem (MSS)

    NASA Technical Reports Server (NTRS)

    Alland, Robert

    2011-01-01

    This paper describes my work with the Cassini Mission Sequence Subsystem (MSS) team during the summer of 2011. It gives some background on the motivation for this project and describes the expected benefit to the Cassini program. It then introduces the two tasks that I worked on - an automatic system auditing tool and a series of corrections to the Cassini Sequence Generator (SEQ_GEN) - and the specific objectives these tasks were to accomplish. Next, it details the approach I took to meet these objectives and the results of this approach, followed by a discussion of how the outcome of the project compares with my initial expectations. The paper concludes with a summary of my experience working on this project, lists what the next steps are, and acknowledges the help of my Cassini colleagues.

  11. Preprototype nitrogen supply subsystem development

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

    1981-01-01

    A nitrogen supply subsystem based on the dissociation of hydrazine into a mixture of hydrogen and nitrogen is developed. The latter is separated to provide makeup nitrogen to control the composition of spacecraft atmospheres. Specific hardware developments resulted in the design and fabrication of a nominal 3.6 kg/d nitrogen generation module. The design integrates a hydrazine catalytic dissociator, three ammonia dissociation stages and four hydrogen separation stages into a 33 kg, 14 cu dm module. A technique was devised to alternate the ammonia dissociation and hydrogen separation stages to give high nitrogen purity in the end product stream. Tests show the product stream to contain less than 0.5 percent hydrogen and 10 parts per million ammonia. The design and development of a test stand for the nitrogen generation module and a series of tests which verified its operation and performance capability are described.

  12. Keck adaptive optics: control subsystem

    SciTech Connect

    Brase, J.M.; An, J.; Avicola, K.

    1996-03-08

    Adaptive optics on the Keck 10 meter telescope will provide an unprecedented level of capability in high resolution ground based astronomical imaging. The system is designed to provide near diffraction limited imaging performance with Strehl {gt} 0.3 n median Keck seeing of r0 = 25 cm, T =10 msec at 500 nm wavelength. The system will be equipped with a 20 watt sodium laser guide star to provide nearly full sky coverage. The wavefront control subsystem is responsible for wavefront sensing and the control of the tip-tilt and deformable mirrors which actively correct atmospheric turbulence. The spatial sampling interval for the wavefront sensor and deformable mirror is de=0.56 m which gives us 349 actuators and 244 subapertures. This paper summarizes the wavefront control system and discusses particular issues in designing a wavefront controller for the Keck telescope.

  13. Laser Crosslink Subsystem - An overview

    NASA Astrophysics Data System (ADS)

    Deadrick, R. B.; Deckelman, W. F.

    1992-06-01

    The Laser Crosslink Subsystem (LCS) is a full duplex laser communications terminal in production at McDonnell Douglas Electronics Systems Company. The LCS will provide a data crosslink for geosynchronous satellites. This paper provides an overview of the system design and major elements followed by a brief program history. One LCS is installed on each satellite. The system utilizes a solid state diode pumped Neodymium YAG laser and direct pulse detection to provide 1.28 Mbps data transmission in one direction on the link and 4 Kbps in the other. A single eight inch gimballed telescope provides both the transmit and receive antenna function. After autonomously acquiring, the 200 Hz bandwidth fine tracking system maintains pointing of the 10 microrad optical beam. The LCS began development in 1981. Since then, each of its assemblies has completed-flight qualification testing. The first integrated production unit successfully completed environmental and performance qualification testing in 1990.

  14. Optical components and subsystems: opportunities and challenges

    NASA Astrophysics Data System (ADS)

    Hong, J.; Lee, P.; Zhu, T.; Lee, G.; Xu, K.; Wang, R.

    2006-02-01

    This paper presents a brief review and discussion on the opportunities and challenges facing the optical components and sub-systems vendors. Specifically, this paper discusses some of the current components and sub-system development on the low loss CWDM filters, wavelength blockers, PLC switch arrays, wavelength selective switches, optical protection switching sub-systems, tunable filters and DCMs, and in addition, the fiber-coupled short-wavelength diode-lasers for medical applications.

  15. FUSE satellite electrical power subsystem

    SciTech Connect

    Roufberg, L.; Noah, K.

    1998-07-01

    The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite will be placed into a low earth orbit to investigate astrophysical processes related to the formation and development of the early universe. The FUSE satellite is considered a pathfinder for NASA's Mid-Class Explorers (MIDEX). To reduce mission cost and development time while delivering quality science, NASA has enforced strict cost caps with a clear definition of high-level science objectives. As a result, a significant design driver for the electrical power subsystem (EPS) was to minimize cost. The FUSE EPS is a direct energy transfer, unregulated bus architecture, with batteries directly on the bus and solar array power limted by pulse-width-modulated shunt regulators. The power subsystem electronics (PSE) contains circuitry to control battery charging, provide power to the loads, and provide fault protection. The electronics is based on the PSE which Orbital (formerly, Fairchild Space) designed and built for NASA/GSFC's XTE spacecraft. However, the FUSE PSE design incorporates a number of unique features to meet the mission requirements. To minimize size of the solar panels due to stowed attachment constraints, GaAs/Ge solar cells were selected. This is the first time this type of large area, thinned solar cell with integral bypass diodes are being used for a NASA LEO mission. The solar panels support a satellite load power of 520W. Nickel Cadmium (NiCd) batteries are used which are identical to the RADARSAT-I design, except for different temperature sensors. This is the first mission for which Orbital is using SAFT NiCd batteries. The spacecraft bus, including the EPS, has successfully completed environmental testing and has been delivered for instrument integration. Tradeoffs involved in designing the EPS and selecting components based on the requirements are discussed. Analyses including solar array and battery sizing and energy balance are presented in addition to results from testing the flight

  16. Private quantum subsystems and quasiorthogonal operator algebras

    NASA Astrophysics Data System (ADS)

    Levick, Jeremy; Jochym-O'Connor, Tomas; Kribs, David W.; Laflamme, Raymond; Pereira, Rajesh

    2016-03-01

    We generalize a recently discovered example of a private quantum subsystem to find private subsystems for Abelian subgroups of the n-qubit Pauli group, which exist in the absence of private subspaces. In doing so, we also connect these quantum privacy investigations with the theory of quasiorthogonal operator algebras through the use of tools from group theory and operator theory.

  17. Mission payloads subsystem description, revision 2

    NASA Technical Reports Server (NTRS)

    Williams, J. M.

    1976-01-01

    The Mission Payloads Subsystem (MPLS) which utilizes a simplified trajectory model to generate a list of missions for the Scheduling Algorithm for Mission Planning and Logistics Evaluation (SAMPLE) program is described. The MPLS is the mechanism that forms the basis of input for the other subsystems of SAMPLE and various post processors.

  18. Installation package for the Solaron solar subsystem

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Information that is intended to be a guide for installation, operation, and maintenance of the various solar subsystems is presented. The subsystems consist of the following: collectors, storage, transport (air handler) and controller for heat pump and peak storage. Two prototype residential systems were installed at Akron, Ohio, and Duffield, Virginia.

  19. ACCESS Sub-system Performance

    NASA Astrophysics Data System (ADS)

    Kaiser, Mary Elizabeth; Morris, Matthew J.; Aldoroty, Lauren Nicole; Godon, David; Pelton, Russell; McCandliss, Stephan R.; Kurucz, Robert L.; Kruk, Jeffrey W.; Rauscher, Bernard J.; Kimble, Randy A.; Wright, Edward L.; Benford, Dominic J.; Gardner, Jonathan P.; Feldman, Paul D.; Moos, H. Warren; Riess, Adam G.; Bohlin, Ralph; Deustua, Susana E.; Dixon, William Van Dyke; Sahnow, David J.; Lampton, Michael; Perlmutter, Saul

    2016-01-01

    ACCESS: Absolute Color Calibration Experiment for Standard Stars is a series of rocket-borne sub-orbital missions and ground-based experiments designed to leverage significant technological advances in detectors, instruments, and the precision of the fundamental laboratory standards used to calibrate these instruments to enable improvements in the precision of the astrophysical flux scale through the transfer of laboratory absolute detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 to 1.7 micron bandpass.A cross wavelength calibration of the astrophysical flux scale to this level of precision over this broad a bandpass is relevant for the data used to probe fundamental astrophysical problems such as the SNeIa photometry based measurements used to constrain dark energy theories.We will describe the strategy for achieving this level of precision, the payload and calibration configuration, present sub-system test data, and the status and preliminary performance of the integration and test of the spectrograph and telescope. NASA APRA sounding rocket grant NNX14AH48G supports this work.

  20. The Calipso Thermal Control Subsystem

    NASA Technical Reports Server (NTRS)

    Gasbarre, Joseph F.; Ousley, Wes; Valentini, Marc; Thomas, Jason; Dejoie, Joel

    2007-01-01

    The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) is a joint NASA-CNES mission to study the Earth s cloud and aerosol layers. The satellite is composed of a primary payload (built by Ball Aerospace) and a spacecraft platform bus (PROTEUS, built by Alcatel Alenia Space). The thermal control subsystem (TCS) for the CALIPSO satellite is a passive design utilizing radiators, multi-layer insulation (MLI) blankets, and both operational and survival surface heaters. The most temperature sensitive component within the satellite is the laser system. During thermal vacuum testing of the integrated satellite, the laser system s operational heaters were found to be inadequate in maintaining the lasers required set point. In response, a solution utilizing the laser system s survival heaters to augment the operational heaters was developed with collaboration between NASA, CNES, Ball Aerospace, and Alcatel-Alenia. The CALIPSO satellite launched from Vandenberg Air Force Base in California on April 26th, 2006. Evaluation of both the platform and payload thermal control systems show they are performing as expected and maintaining the critical elements of the satellite within acceptable limits.

  1. 2nd & 3rd Generation Vehicle Subsystems

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This paper contains viewgraph presentation on the "2nd & 3rd Generation Vehicle Subsystems" project. The objective behind this project is to design, develop and test advanced avionics, power systems, power control and distribution components and subsystems for insertion into a highly reliable and low-cost system for a Reusable Launch Vehicles (RLV). The project is divided into two sections: 3rd Generation Vehicle Subsystems and 2nd Generation Vehicle Subsystems. The following topics are discussed under the first section, 3rd Generation Vehicle Subsystems: supporting the NASA RLV program; high-performance guidance & control adaptation for future RLVs; Evolvable Hardware (EHW) for 3rd generation avionics description; Scaleable, Fault-tolerant Intelligent Network or X(trans)ducers (SFINIX); advance electric actuation devices and subsystem technology; hybrid power sources and regeneration technology for electric actuators; and intelligent internal thermal control. Topics discussed in the 2nd Generation Vehicle Subsystems program include: design, development and test of a robust, low-maintenance avionics with no active cooling requirements and autonomous rendezvous and docking systems; design and development of a low maintenance, high reliability, intelligent power systems (fuel cells and battery); and design of a low cost, low maintenance high horsepower actuation systems (actuators).

  2. Intelligent subsystem interface for modular hardware system

    NASA Technical Reports Server (NTRS)

    Krening, Douglas N. (Inventor); Lannan, Gregory B. (Inventor); Schneiderwind, Michael J. (Inventor); Schneiderwind, Robert A. (Inventor); Caffrey, Robert T. (Inventor)

    2000-01-01

    A single chip application specific integrated circuit (ASIC) which provides a flexible, modular interface between a subsystem and a standard system bus. The ASIC includes a microcontroller/microprocessor, a serial interface for connection to the bus, and a variety of communications interface devices available for coupling to the subsystem. A three-bus architecture, utilizing arbitration, provides connectivity within the ASIC and between the ASIC and the subsystem. The communication interface devices include UART (serial), parallel, analog, and external device interface utilizing bus connections paired with device select signals. A low power (sleep) mode is provided as is a processor disable option.

  3. Data Transport Subsystem - The SFOC glue

    NASA Technical Reports Server (NTRS)

    Parr, Stephen J.

    1988-01-01

    The design and operation of the Data Transport Subsystem (DTS) for the JPL Space Flight Operation Center (SFOC) are described. The SFOC is the ground data system under development to serve interplanetary space probes; in addition to the DTS, it comprises a ground interface facility, a telemetry-input subsystem, data monitor and display facilities, and a digital TV system. DTS links the other subsystems via an ISO OSI presentation layer and an LAN. Here, particular attention is given to the DTS services and service modes (virtual circuit, datagram, and broadcast), the DTS software architecture, the logical-name server, the role of the integrated AI library, and SFOC as a distributed system.

  4. Thermo-mechanical evolution of the magmatic plumbing system of Soufrière Hills volcano, Montserrat, and resultant ground deformation

    NASA Astrophysics Data System (ADS)

    Gottsmann, Joachim; Odbert, Henry

    2014-05-01

    We exploit cyclic ground deformation timeseries from Soufrière Hills volcano expressed by ground uplift during reservoir priming and subsidence during extrusion. This study focuses on the period of eruptive repose between July 2003 and August 2005 marked by ground uplift prior to renewed dome growth thereafter. Using finite - element analysis we simulate the stress and pressure evolution in the magmatic plumbing system using a time-dependent, non-linear pressure-time history and inelastic thermo-mechanical properties of the upper crust. We compare two models of the plumbing system assembly: 1) two stacked spheroidal reservoirs and 2) a single prolate reservoir. In addition, two different crustal rheology models are tested for each of the plumbing models, with one order of magnitude difference in near-surface (<1 km) rock stiffness. Assuming reasonable values for the tensile strength of encasing rocks as proxies for reservoir excess pressure (1 to 10 MPa), we use the deformation timeseries as a reservoir barometer. We compare the amplitude of pre-eruptive pressurisation capable of explaining the observed ground displacements from the four best-fit time-dependent model designs with pressure changes deduced for purely elastic mechanical conditions. We find that assuming an elastic rheology for the upper crust beneath Montserrat requires unrealistically low rock rigidities with values on the order of 100 MPa - similar to rubber or beeswax - to fit both near and far-field deformation data. Although one might invoke such low rigidities in the immediate (heated) vicinity of an active magmatic plumbing system, they are unreasonable to assume over a large subsurface volume. Our results show that the thermal perturbation of the geotherm by the presence of a hot plumbing system is significant and fundamentally alters the portioning of subsurface stresses and strains. We further find that the thermal perturbation caused by best-fitting dual source and single source models are

  5. Introducing tectonically and thermo-mechanically realistic lithosphere in the models of plume head -lithosphere interactions (PLI) including intra-continental plate boundaries.

    NASA Astrophysics Data System (ADS)

    Guillou-Frottier, L.; Burov, E.; Cloetingh, S.

    2007-12-01

    Plume-Lithosphere Interactions (PLI) in continets have complex topographic and magmatic signatures and are often identified near boundaries between younger plates (e.g., orogenic) and older stable plates (e.g., cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume head (e.g., Archean West Africa, East Africa, Pannonian - Carpathian system). The observable PLI signatures are conditioned by plume dynamics but also by complex rheology and structure of continental lithosphere. We address this problem by considering a new free-surface thermo-mechanical numerical model of PLI with two stratified elasto-viscous-plastic (EVP) continental plates of contrasting age, thickness and structure. The results show that: (1) surface deformation is poly-harmonic and contains smaller wavelengths (50-500 km) than that associated with the plume head (>1000 km). (2) below intra-plate boundaries, plume head flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to mechanical decoupling of crust from mantle lithosphere, and to localized faulting at the cratonic margin; (2) the return flow from the plume head results in sub-vertical down-thrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume head flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the "craton side"; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh-Taylor instabilities in the lithosphere above the plume head provide a mechanism for crustal

  6. Ongoing compression triggered exhumation of the orogenic crust in the Variscan Maures-Tanneron Massif, France - Geological arguments and thermo-mechanical tests

    NASA Astrophysics Data System (ADS)

    Gerbault, Muriel; Schneider, Julie; Reverso-Peila, Alexandre; Corsini, Michel

    2016-04-01

    The Maures-Tanneron Massif (MTM), together with Corsica and Sardinia, hosted the South-Eastern Variscan belt and record a continuous evolution from continental collision to exhumation. We present a synthesis of the available geological and geochronogical data that explores the transition from convergence to perpendicular Permean extension in the MTM (at ~ 325 Ma ± 25 My). The migmatitic Internal Zone that composes the Western MTM displays structural clues such as backthrusting and magmatic foliations, and metamorphic data indicating exhumation of deep seated partially molten rocks at an apparent heating rate of 1-2 °C/km/My from ca. 345 Ma to 320 Ma. This suggests vertical advective heat transport during continued N140° convergence (D2 phase). In contrast at the same time, the low grade External zone composing the Eastern part of the MTM recorded exhumation of more conductive patterns at an apparent rate of 0.3-0.6 °C/km/My. It is only from ca. 320 Ma that transcurrent motion dominates in the Internal zone and progressively leaves way to N-S strecthing (D3 phase), indicative of orogenic collapse and extension and in asociation with emplacement of larger volumes of magmatism in the crust. Thermo-mechanical modeling complements this synthesis in order to highlight the conditions under which deep seated HP units could melt and massively start to exhume during maintained convergence (phase D2). Accounting for temperature dependent elasto-visco-plastic rheologies, our models explore the dynamics of an orogenic prism starting from a dis-equilibrated state just after slab break-off or delamination, at ca. 350 Ma. We simulate the development of gravitational instabilities in partially melting crust, a process that is already well known to depend on strain-rate, heat sources and strength layering. In order to reproduce the exhumation patterns of rocks from ~50 km depth over the appropriate time-scale (>20 My) and spatial extent (>100 km), a best fit was obtained with a

  7. Glacial landscape evolution on Hall Peninsula, Baffin Island, since the Last Glacial Maximum: insights into switching glacial dynamics and thermo-mechanical conditions

    NASA Astrophysics Data System (ADS)

    Johnson, C. L.; Ross, M.

    2012-12-01

    channelized zones (GTZ 2) suggests a switch from warm to cold-based conditions over large areas while warm-based conditions prevailed within the channelized flow zone. This record may reflect the transition from LGM (thick warm-based ice) to thinner topographically-controlled ice, with cold-based patches, during early deglaciation. The catchment zones of the channelized system locally extended into the central area of Hall Peninsula (GTZ 3) which is reflected in till dispersal patterns and the striation record. The retreat of the LIS was later marked by southeastward readvances and/or surges (GTZ 4) and short-lived glacial lakes whose location requires ice to be maintained over GTZ 1. Thin cold-based ice remaining over GTZ 1 may explain the preservation of the inferred LGM landscape in that zone during deglacial events. The glacial landscape of Hall Peninsula reflects the effect of a switch from uniform warm-based ice and laterally extensive erosive basal sliding during LGM to a channelized flow during deglaciation and intervening cold-based zones. The change in basal thermo-mechanical conditions and the geometry of the channelized flow system may be precursor controlling factors to the development and shape of post LIS ice caps in this part of the Canadian Arctic.

  8. Magnitude of long-term non-lithostatic pressure variations in lithospheric processes: insight from thermo-mechanical subduction/collision models

    NASA Astrophysics Data System (ADS)

    Gerya, Taras

    2014-05-01

    On the one hand, the principle of lithostatic pressure is habitually used in metamorphic geology to calculate paleo-depths of metamorphism from mineralogical pressure estimates given by geobarometry. On the other hand, it is obvious that this lithostatic (hydrostatic) pressure principle should only be valid for an ideal case of negligible deviatoric stresses during the long-term development of the entire tectono-metamorphic system - the situation, which newer comes to existence in natural lithospheric processes. The question is therefore not "Do non-lithostatic pressure variations exist?" but " What is the magnitude of long-term non-lithostatic pressure variations in various lithospheric processes, which can be recorded by mineral equilibria of respective metamorphic rocks?". The later question is, in particular, relevant for various types of high-pressure (HP) and ultrahigh-pressure (UHP) rocks, which are often produced in convergent plate boundary settings (e.g., Hacker and Gerya, 2013). This question, can, in particular, be answered with the use of thermo-mechanical models of subduction/collision processes employing realistic P-T-stress-dependent visco-elasto-brittle/plastic rheology of rocks. These models suggest that magnitudes of pressure deviations from lithostatic values can range >50% underpressure to >100% overpressure, mainly in the regions of bending of rheologically strong mantle lithosphere (Burg and Gerya, 2005; Li et al., 2010). In particular, strong undepresures along normal faults forming within outer rise regions of subducting plates can be responsible for downward water suction and deep hydration of oceanic slabs (Faccenda et al., 2009). Weaker HP and UHP rocks of subduction/collision channels are typically subjected to lesser non-lithostatic pressure variations with characteristic magnitudes ranging within 10-20% from the lithostatic values (Burg and Gerya, 2005; Li et al., 2010). The strength of subducted crustal rocks and the degree of

  9. Igneous Cooling Rate constraints on the Accretion of the lower Oceanic Crust in Mid-ocean Ridges: Insights from a new Thermo-mechanical Model

    NASA Astrophysics Data System (ADS)

    Garrido, C. J.; Machetel, P.

    2005-12-01

    We report the results of a new thermo-mechanical model of crustal flow beneath fast spreading mid-ocean ridges to investigate both the effect of deep, near off-axis hydrothermal convection on the thermal structure of the magma chamber and the role of variable number of melt intrusions on the accretion of the oceanic crust. In our model the melt is injected at the center of the axial magma chamber with a 'needle' with adjustable porosity at different depths allowing the simulation of different arrangements of melt injection and supply within the magma chamber. Conversely to previous models, the shape of the magma chamber -defined as the isotherm where 95% solidification of the melt occurs- is not imposed but computed from the steady state reached by the thermal field considering the heat diffusion and advection and the latent heat of crystallization. The motion equation is solved for a temperature and phase dependent viscosity. The thermal diffusivity is also dependent on temperature and depth, with a higher diffusivity in the upper plutonic crust to account for more efficient hydrothermal cooling at these crustal levels. In agreement with previous non-dynamic thermal models, our results show that near, deep off-axis hydrothermal circulation strongly affects the shape of the axial magma by tightening isotherms in the upper half of the plutonic oceanic crust where hydrothermal cooling is more efficient. Different accretion modes have however little effect on the shape of the magma chamber, but result in variable arrangements of flow lines ranging from tent-shape in a single-lens accretion scenario to sub-horizontal in "sheeted-sill" intrusion models. For different intrusion models, we computed the average Igneous Cooling Rates (ICR) of gabbros by dividing the crystallization temperature interval of gabbros by the integrated time, from the initial intrusion to the point where it crossed the 950 °C isotherm where total solidification of gabbro occurs, along individual

  10. More About Beam-Steering Subsystem For Laser Communication

    NASA Technical Reports Server (NTRS)

    Page, Norman A.; Chen, Chien-Chu; Hemmati, Hamid; Lesh, James R.

    1995-01-01

    Two reports present additional information about developmental beam-steering subsystem of laser-communication system. Aspects of this subsystem described previously in "Beam-Steering Subsystem for Laser Communication" (NPO-19069) and "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193). Reports reiterate basic principles of operation of beam-steering subsystem and of laser-communication system as whole. Also presents some of details of optical and mechanical design of prototype of subsystem, called Optical Communication Demonstrator.

  11. Solar electric propulsion thrust subsystem development

    NASA Technical Reports Server (NTRS)

    Masek, T. D.

    1973-01-01

    The Solar Electric Propulsion System developed under this program was designed to demonstrate all the thrust subsystem functions needed on an unmanned planetary vehicle. The demonstration included operation of the basic elements, power matching input and output voltage regulation, three-axis thrust vector control, subsystem automatic control including failure detection and correction capability (using a PDP-11 computer), operation of critical elements in thermal-vacuum-, zero-gravity-type propellant storage, and data outputs from all subsystem elements. The subsystem elements, functions, unique features, and test setup are described. General features and capabilities of the test-support data system are also presented. The test program culminated in a 1500-h computer-controlled, system-functional demonstration. This included simultaneous operation of two thruster/power conditioner sets. The results of this testing phase satisfied all the program goals.

  12. Goddard trajectory determination subsystem: Mathematical specifications

    NASA Technical Reports Server (NTRS)

    Wagner, W. E. (Editor); Velez, C. E. (Editor)

    1972-01-01

    The mathematical specifications of the Goddard trajectory determination subsystem of the flight dynamics system are presented. These specifications include the mathematical description of the coordinate systems, dynamic and measurement model, numerical integration techniques, and statistical estimation concepts.

  13. A statistical design of experiments for optimizing the MALDI-TOF-MS sample preparation of polymers. An application in the assessment of the thermo-mechanical degradation mechanisms of poly (ethylene terephthalate).

    PubMed

    Badía, J D; Strömberg, E; Ribes-Greus, A; Karlsson, S

    2011-04-29

    The sample preparation procedure for MALDI-TOF MS of polymers is addressed in this study by the application of a statistical Design of Experiments (DoE). Industrial poly (ethylene terephthalate) (PET) was chosen as model polymer. Different experimental settings (levels) for matrixes, analyte/matrix proportions and concentrations of cationization agent were considered. The quality parameters used for the analysis were signal-to-noise ratio and resolution. A closer inspection of the statistical results provided the study not only with the best combination of factors for the MALDI sample preparation, but also with a better understanding of the influence of the different factors, individually or in combination, to the signal. The application of DoE for the improvement of the MALDI measure of PET stated that the best combination of factors and levels was the following: matrix (dithranol), proportion analyte/matrix/cationization agent (1/15/1, V/V/V), and concentration of cationization agent (2 g L(-1)). In a second part, multiple processing by means of successive injection cycles was used to simulate the thermo-mechanical degradation effects on the oligomeric distribution of PET under mechanical recycling. The application of MALDI-TOF-MS showed that thermo-mechanical degradation primarily affected initially predominant cyclic species. Several degradation mechanisms were proposed, remarking intramolecular transesterification and hydrolysis. The ether links of the glycol unit in PET were shown to act as potential reaction sites, driving the main reactions of degradation.

  14. Periodic subsystem density-functional theory

    SciTech Connect

    Genova, Alessandro; Pavanello, Michele; Ceresoli, Davide

    2014-11-07

    By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn–Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn–Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.

  15. Lightning testing at the subsystem level

    NASA Technical Reports Server (NTRS)

    Luteran, Frank

    1991-01-01

    Testing at the subsystem or black box level for lightning hardness is required if system hardness is to be assured at the system level. The often applied philosophy of lighting testing only at the system level leads to extensive end of the line design changes which result in excessive costs and time delays. In order to perform testing at the subsystem level two important factors must be defined to make the testing simulation meaningful. The first factor is the definition of the test stimulus appropriate to the subsystem level. Application of system level stimulations to the subsystem level usually leads to significant overdesign of the subsystem which is not necessary and may impair normal subsystem performance. The second factor is the availability of test equipment needed to provide the subsystem level lightning stimulation. Equipment for testing at this level should be portable or at least movable to enable efficient testing in a design laboratory environment. Large fixed test installations for system level tests are not readily available for use by the design engineers at the subsystem level and usually require special operating skills. The two factors, stimulation level and test equipment availability, must be evaluated together in order to produce a practical, workable test standard. The neglect or subordination of either factor will guarantee failure in generating the standard. It is not unusual to hear that test standards or specifications are waived because a specified stimulation level cannot be accomplished by in-house or independent test facilities. Determination of subsystem lightning simulation level requires a knowledge and evaluation of field coupling modes, peak and median levels of voltages and currents, bandwidths, and repetition rates. Practical limitations on test systems may require tradeoffs in lightning stimulation parameters in order to build practical test equipment. Peak power levels that can be generated at specified bandwidths with

  16. Engineering model 8-cm thruster subsystem

    NASA Technical Reports Server (NTRS)

    Herron, B. G.; Hyman, J.; Hopper, D. J.; Williamson, W. S.; Dulgeroff, C. R.; Collett, C. R.

    1978-01-01

    An Engineering Model (EM) 8 cm Ion Thruster Propulsion Subsystem was developed for operation at a thrust level 5 mN (1.1 mlb) at a specific impulse 1 sub sp = 2667 sec with a total system input power P sub in = 165 W. The system dry mass is 15 kg with a mercury-propellant-reservoir capacity of 8.75 kg permitting uninterrupted operation for about 12,500 hr. The subsystem can be started from a dormant condition in a time less than or equal to 15 min. The thruster has a design lifetime of 20,000 hr with 10,000 startup cycles. A gimbal unit is included to provide a thrust vector deflection capability of + or - 10 degrees in any direction from the zero position. The EM subsystem development program included thruster optimization, power-supply circuit optimization and flight packaging, subsystem integration, and subsystem acceptance testing including a cyclic test of the total propulsion package.

  17. Air and water quality monitor assessment of life support subsystems

    NASA Technical Reports Server (NTRS)

    Whitley, Ken; Carrasquillo, Robyn L.; Holder, D.; Humphries, R.

    1988-01-01

    Preprotype air revitalization and water reclamation subsystems (Mole Sieve, Sabatier, Static Feed Electrolyzer, Trace Contaminant Control, and Thermoelectric Integrated Membrane Evaporative Subsystem) were operated and tested independently and in an integrated arrangement. During each test, water and/or gas samples were taken from each subsystem so that overall subsystem performance could be determined. The overall test design and objectives for both subsystem and integrated subsystem tests were limited, and no effort was made to meet water or gas specifications. The results of chemical analyses for each of the participating subsystems are presented along with other selected samples which were analyzed for physical properties and microbiologicals.

  18. Embedded Thermal Control for Spacecraft Subsystems Miniaturization

    NASA Technical Reports Server (NTRS)

    Didion, Jeffrey R.

    2014-01-01

    Optimization of spacecraft size, weight and power (SWaP) resources is an explicit technical priority at Goddard Space Flight Center. Embedded Thermal Control Subsystems are a promising technology with many cross cutting NSAA, DoD and commercial applications: 1.) CubeSatSmallSat spacecraft architecture, 2.) high performance computing, 3.) On-board spacecraft electronics, 4.) Power electronics and RF arrays. The Embedded Thermal Control Subsystem technology development efforts focus on component, board and enclosure level devices that will ultimately include intelligent capabilities. The presentation will discuss electric, capillary and hybrid based hardware research and development efforts at Goddard Space Flight Center. The Embedded Thermal Control Subsystem development program consists of interrelated sub-initiatives, e.g., chip component level thermal control devices, self-sensing thermal management, advanced manufactured structures. This presentation includes technical status and progress on each of these investigations. Future sub-initiatives, technical milestones and program goals will be presented.

  19. Thermoelectric Integrated Membrane Evaporation Subsystem operational improvements

    NASA Technical Reports Server (NTRS)

    Dehner, G. F.; Winkler, H. E.; Reysa, R. P.

    1984-01-01

    A three-man preprototype Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) has been developed to provide high quality water recovery from waste fluids on extended duration space flights. In the most recent effort, a number of improvements have been made to simplify subsystem operation and increase performance. These modifications include changes to the hollow fiber membrane evaporator, the condensing section of the thermoelectric heat pump, and the electronic controller logic and display. This paper describes the results of the test program that was conducted to evaluate the implemented improvements. In addition, an advanced design concept is discussed that will provide lower electrical power consumption, greater water production capacity, lower weight, and a smaller package than the present subsystem configuration.

  20. Electrochemical energy storage subsystems study, volume 1

    NASA Technical Reports Server (NTRS)

    Miller, F. Q.; Richardson, P. W.; Graff, C. L.; Jordan, M. V.; Patterson, V. L.

    1981-01-01

    The effects on life cycle costs (LCC) of major design and performance technology parameters for multi kW LEO and GEO energy storage subsystems using NiCd and NiH2 batteries and fuel cell/electrolysis cell devices were examined. Design, performance and LCC dynamic models are developed based on mission and system/subsystem requirements and existing or derived physical and cost data relationships. The models define baseline designs and costs. The major design and performance parameters are each varied to determine their influence on LCC around the baseline values.

  1. Laboratory measurements of on-board subsystems

    NASA Technical Reports Server (NTRS)

    Nuspl, P. P.; Dong, G.; Seran, H. C.

    1991-01-01

    Good progress was achieved on the test bed for on-board subsystems for future satellites. The test bed is for subsystems developed previously. Four test setups were configured in the INTELSAT technical labs: (1) TDMA on-board modem; (2) multicarrier demultiplexer demodulator; (3) IBS/IDR baseband processor; and (4) baseband switch matrix. The first three series of tests are completed and the tests on the BSM are in progress. Descriptions of test setups and major test results are included; the format of the presentation is outlined.

  2. Electrochemical Energy Storage Subsystems Study, Volume 2

    NASA Technical Reports Server (NTRS)

    Miller, F. Q.; Richardson, P. W.; Graff, C. L.; Jordan, M. V.; Patterson, V. L.

    1981-01-01

    The effects on life cycle costs (LCC) of major design and performance technology parameters for multi kW LEO and GEO energy storage subsystems using NiCd and NiH2 batteries and fuel cell/electrolysis cell devices were examined. Design, performance and LCC dynamic models are developed based on mission and system/subsystem requirements and existing or derived physical and cost data relationships. The models are exercised to define baseline designs and costs. Then the major design and performance parameters are each varied to determine their influence on LCC around the baseline values.

  3. Timing subsystem development: Network synchronization experiments

    NASA Technical Reports Server (NTRS)

    Backe, K. R.

    1983-01-01

    This paper describes a program in which several experimental timing subsystem prototypes were designed, fabricated, and field tested using a small network of troposcatter and microwave digital communication links. This equipment was responsible for modem/radio interfacing, time interval measurement, clock adjustment and distribution, synchronization technique, and node to node information exchange. Presented are discussions of the design approach, measurement plan, and performance assessment methods. Recommendations are made based on the findings of the test program and an evaluation of the design of both the hardware and software elements of the timing subsystem prototypes.

  4. A Subsystem-Independent Generalization of Entanglement

    NASA Astrophysics Data System (ADS)

    Barnum, Howard; Knill, Emanuel; Ortiz, Gerardo; Somma, Rolando; Viola, Lorenza

    2004-03-01

    We present a generalization of entanglement based on the idea that entanglement is relative to a distinguished subspace of observables rather than a distinguished subsystem decomposition. A pure quantum state is entangled relative to such a subspace if its expectations are a proper mixture of those of other states. Many information-theoretic aspects of entanglement can be extended to this observable-based setting, suggesting new ways of measuring and classifying multipartite entanglement. By going beyond the distinguishable-subsystem framework, generalized entanglement also provides novel tools for probing quantum correlations in interacting many-body systems.

  5. Small spacecraft power and thermal subsystems

    NASA Technical Reports Server (NTRS)

    Eakman, D.; Lambeck, R.; Mackowski, M.; Slifer, L., Jr.

    1994-01-01

    This white paper provides a general guide to the conceptual design of satellite power and thermal control subsystems with special emphasis on the unique design aspects associated with small satellites. The operating principles of these technologies are explained and performance characteristics of current and projected components are provided. A tutorial is presented on the design process for both power and thermal subsystems, with emphasis on unique issues relevant to small satellites. The ability of existing technology to meet future performance requirements is discussed. Conclusions and observations are presented that stress cost-effective, high-performance design solutions.

  6. MIUS integration and subsystems test program

    NASA Technical Reports Server (NTRS)

    Beckham, W. S., Jr.; Shows, G. C.; Redding, T. E.; Wadle, R. C.; Keough, M. B.; Poradek, J. C.

    1976-01-01

    The MIUS Integration and Subsystems Test (MIST) facility at the Lyndon B. Johnson Space Center was completed and ready in May 1974 for conducting specific tests in direct support of the Modular Integrated Utility System (MIUS). A series of subsystems and integrated tests was conducted since that time, culminating in a series of 24-hour dynamic tests to further demonstrate the capabilities of the MIUS Program concepts to meet typical utility load profiles for a residential area. Results of the MIST Program are presented which achieved demonstrated plant thermal efficiencies ranging from 57 to 65 percent.

  7. JOB BUILDER remote batch processing subsystem

    NASA Technical Reports Server (NTRS)

    Orlov, I. G.; Orlova, T. L.

    1980-01-01

    The functions of the JOB BUILDER remote batch processing subsystem are described. Instructions are given for using it as a component of a display system developed by personnel of the System Programming Laboratory, Institute of Space Research, USSR Academy of Sciences.

  8. Space Interferometry Mission starlight and metrology subsystems

    NASA Astrophysics Data System (ADS)

    Ames, Lawrence L.; Barrett, Stephanie D.; Calhoon, Stuart J.; Kvamme, Eric T.; Mason, James E.; Oseas, Jeffrey M.; Pryor, Mark; Schaechter, David B.; Stubbs, David M.

    2003-02-01

    The Space Interferometry Mission (SIM), planned for launch in 2009, will measure the positions of celestial objects to an unprecedented accuracy of 4.0 microarcseconds. In order to achieve this accuracy, which represents an improvement of almost two orders of magnitude over previous astrometric measurements, a ten-meter baseline interferometer will be flown in space. NASA challenges JPL and its industrial partners, Lockheed Martin and TRW, to develop an affordable mission. This challenge will be met using a combination of existing designs and new technology. Performance and affordability must be balanced with a cost-conscious Systems Engineering approach to design and implementation trades. This paper focuses on the Lockheed Martin-led Starlight (STL) and Metrology (MET) subsystems within the main instrument of SIM. Starlight is collected by 35cm diameter telescopes to form fringes on detectors. To achieve the stated accuracy, the position of these white-light fringes must be measured to 10-9 of a wavelength of visible light. The STL Subsystem consists of siderostats, telescopes, fast steering mirrors, roof mirrors, optical delay lines and beam combiners. The MET Subsystem is used to measure very precisely the locations of the siderostats with respect to one another as well as to measure the distance traveled by starlight from the siderostat mirrors and reference corner cubes through the system to a point very close to the detectors inside the beam combiners. The MET subsystem consists of beam launchers, double and triple corner cubes, and a laser distribution system.

  9. SPECTROSCOPIC SUBSYSTEMS IN NEARBY WIDE BINARIES

    SciTech Connect

    Tokovinin, Andrei

    2015-12-15

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5 m telescope to study short-period systems. The data reduction is described, and mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, and for some of them the orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67 pc. It is found that 43 binaries contain at least one subsystem, and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods matches the simple prescription proposed by the author. The remaining 53 simple wide binaries with a median projected separation of 1300 AU have an RV difference distribution between their components that is not compatible with the thermal eccentricity distribution f (e) = 2e but rather matches the uniform eccentricity distribution.

  10. The charged particle accelerators subsystems modeling

    NASA Astrophysics Data System (ADS)

    Averyanov, G. P.; Kobylyatskiy, A. V.

    2017-01-01

    Presented web-based resource for information support the engineering, science and education in Electrophysics, containing web-based tools for simulation subsystems charged particle accelerators. Formulated the development motivation of Web-Environment for Virtual Electrophysical Laboratories. Analyzes the trends of designs the dynamic web-environments for supporting of scientific research and E-learning, within the framework of Open Education concept.

  11. The Digital Electronic Subsystem of Marsis

    NASA Astrophysics Data System (ADS)

    Maltecca, L.; Pecora, M.; Scandelli, L.

    MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) is one of the Instrument of the ESA Mars Express mission, to be launched in June 2003 with a Soyuz/Fregate. Its primary objective is to map the distribution of water, both liquid and solid, in the upper portions of the crust of Mars. Secondary objectives are subsurface geologic probing, surface characterisation and ionosphere sounding. The MARSIS instrument is a low-frequency nadir-looking pulse limited radar sounder and altimeter with ground penetration capabilities, which uses synthetic aperture techniques and a secondary-receiving antenna to isolate subsurface reflections. Functionally and also from the responsibility point of view of each organisation involved in MARSIS, the instrument can be split into three subsystems: - Antenna: ANT - Radio Frequency Subsystem: RFS (TX+RX) - Digital Electronics Subsystem: DES MARSIS is an international co-operation between Italian Space Agency (ASI) and National Aeronautics and Space Administration (NASA). The experiment has an Italian Principal investigator (from Infocom Dept. of University of Rome "La Sapienza"), an U.S. Co-PI (from Jet Propulsion Laboratory), and Co-I~@~Ys from Italy, the U.S. and other countries. Italy is the lead for the experiment definition with the participation of the U.S.. In particular Alenia Spazio/Rome is the Prime Contractor of the industrial team and also supplier of part of the RF subsystem. Laben (a company of Finmeccanica) is the supplier of the Digital Electronic Subsystem (DES), including its basic and application SW, as subcontractor of ALS. The purpose of this paper is to describe the DES from HW and SW point of view, including the Test Equipment and the special simulator developed used for DES validation.

  12. Debris measure subsystem of the nanosatellite IRECIN

    NASA Astrophysics Data System (ADS)

    Ferrante, M.; di Ciolo, L.; Ortenzi, A.; Petrozzi, M.; del Re, V.

    2003-09-01

    The on board resources, needed to perform the mission tasks, are very limited in nano-satellites. This paper proposes an Electronic real-time system that acquires space debris measures. It uses a piezo-electric sensor. The described device is a subsystem on board of the IRECIN nanosatellite composed mainly by a r.i.s.c. microprocessor, an electronic part that interfaces to the debris sensor in order to provide a low noise electrical and suitable range to ADC 12 bit converter, and finally a memory in order to store the data. The microprocessor handles the Debris Measure System measuring the impacts number, their intensity and storing their waves form. This subsystem is able to communicate with the other IRECIN subsystems through I2C Bus and principally with the "Main Microprocessor" subsystem allowing the data download directly to the Ground Station. Moreover this subsystem lets free the "Main Microprocessor Board" from the management and charge of debris data. All electronic components are SMD technology in order to reduce weight and size. The realized Electronic board are completely developed, realized and tested at the Vitrociset S.P.A. under control of Research and Development Group. The proposed system is implemented on the IRECIN, a modular nanosatellite weighting less than 1.5 kg, constituted by sixteen external sides with surface-mounted solar cells and three internal Al plates, kept together by four steel bars. Lithium-ions batteries are added for eclipse operations. Attitude is determined by two three-axis magnetometers and the solar panels data. Control is provided by an active magnetic control system. The spacecraft will be spin-stabilized with the spin-axis normal to the orbit. debris and micrometeoroids mass and velocity.

  13. National Ingition Facility subsystem design requirements pockels cell subsystem SSDR 1.3.3

    SciTech Connect

    Rhodes, M.

    1996-10-31

    This Subsystem Design Requirement document is a development specification that establishes the performance, design, development, and test requirements for the Pockels cell subsystem (WBS 1.3.3) of the NIF Laser System (WBS 1.3). The NIF is a multi-pass, 192-beam, high-power, neodymium-glass laser that meets requirements set forth in the NIF SDR 002 (Laser System). 5 figs., 1 tab.

  14. Advances in ROADM technologies and subsystems

    NASA Astrophysics Data System (ADS)

    Eldada, Louay

    2005-09-01

    Until recently, reconfigurable optical add/drop multiplexer (ROADM) systems did not exist, their components were unselected, and their market was unclear. Today, every major system vendor has a ROADM offering, and a large number of component vendors have announced ROADM products based on a variety of technologies, some more mature than others. We review the different optical component technologies that have been developed for use in ROADM subsystems, and describe their principles of operation, designs, advantages, and challenges. The technology platforms that we cover include MEMS, liquid crystals (liquid crystal devices (LCD) and liquid crystal on silicon (LCoS) technologies), and monolithic and hybrid planar lightwave circuits (PLC) based on silica on silicon and polymer on silicon platforms. For each technology, we describe the corresponding ROADM subsystem architectures in terms of functionality, features, size, cost, and maturity.

  15. Analysis of the human operator subsystems

    NASA Technical Reports Server (NTRS)

    Jones, Lynette A.; Hunter, Ian W.

    1991-01-01

    Except in low-bandwidth systems, knowledge of the human operator transfer function is essential for high-performance telerobotic systems. This information has usually been derived from detailed analyses of tracking performance, in which the human operator is considered as a complete system rather than as a summation of a number of subsystems, each of which influences the operator's output. Studies of one of these subsystems, the limb mechanics system, demonstrate that large parameter variations can occur that can have a profound effect on the stability of force-reflecting telerobot systems. An objective of this research was to decompose the performance of the human operator system in order to establish how the dynamics of each of the elements influence the operator's responses.

  16. Wideband embedded/conformal antenna subsystem concept

    NASA Astrophysics Data System (ADS)

    Smalanskas, Joseph P.; Valentine, Gary W.; Wolfson, Ronald I.

    1991-10-01

    The concept for a wideband, embedded/conformal antenna subsystem is presented. A multilayer radome not only protects the antenna from hostile environments, but also is designed to sustain aircraft dynamic loading. The radiating element consists of a planar, dual- flared slot capable of high-performance, multioctave operation. Advanced materials are currently being developed to enhance the low profile and efficient, wideband performance of the radiating element.

  17. Apollo experience report: Electrical wiring subsystem

    NASA Technical Reports Server (NTRS)

    White, L. D.

    1975-01-01

    The general requirements of the electrical wiring subsystems and the problem areas and solutions that occurred during the major part of the Apollo Program are detailed in this report. The concepts and definitions of specific requirements for electrical wiring; wire-connecting devices; and wire-harness fabrication, checkout, and installation techniques are discussed. The design and development of electrical wiring and wire-connecting devices are described. Mission performance is discussed, and conclusions and recommendations for future programs are presented.

  18. Subsystem codes with spatially local generators

    SciTech Connect

    Bravyi, Sergey

    2011-01-15

    We study subsystem codes whose gauge group has local generators in two-dimensional (2D) geometry. It is shown that there exists a family of such codes defined on lattices of size LxL with the number of logical qubits k and the minimum distance d both proportional to L. The gauge group of these codes involves only two-qubit generators of type XX and ZZ coupling nearest-neighbor qubits (and some auxiliary one-qubit generators). Our proof is not constructive as it relies on a certain version of the Gilbert-Varshamov bound for classical codes. Along the way, we introduce and study properties of generalized Bacon-Shor codes that might be of independent interest. Secondly, we prove that any 2D subsystem [n,k,d] code with spatially local generators obeys upper bounds kd=O(n) and d{sup 2}=O(n). The analogous upper bound proved recently for 2D stabilizer codes is kd{sup 2}=O(n). Our results thus demonstrate that subsystem codes can be more powerful than stabilizer codes under the spatial locality constraint.

  19. Subsystem codes with spatially local generators

    NASA Astrophysics Data System (ADS)

    Bravyi, Sergey

    2011-01-01

    We study subsystem codes whose gauge group has local generators in two-dimensional (2D) geometry. It is shown that there exists a family of such codes defined on lattices of size L×L with the number of logical qubits k and the minimum distance d both proportional to L. The gauge group of these codes involves only two-qubit generators of type XX and ZZ coupling nearest-neighbor qubits (and some auxiliary one-qubit generators). Our proof is not constructive as it relies on a certain version of the Gilbert-Varshamov bound for classical codes. Along the way, we introduce and study properties of generalized Bacon-Shor codes that might be of independent interest. Secondly, we prove that any 2D subsystem [n,k,d] code with spatially local generators obeys upper bounds kd=O(n) and d2=O(n). The analogous upper bound proved recently for 2D stabilizer codes is kd2=O(n). Our results thus demonstrate that subsystem codes can be more powerful than stabilizer codes under the spatial locality constraint.

  20. Automated searching for quantum subsystem codes

    SciTech Connect

    Crosswhite, Gregory M.; Bacon, Dave

    2011-02-15

    Quantum error correction allows for faulty quantum systems to behave in an effectively error-free manner. One important class of techniques for quantum error correction is the class of quantum subsystem codes, which are relevant both to active quantum error-correcting schemes as well as to the design of self-correcting quantum memories. Previous approaches for investigating these codes have focused on applying theoretical analysis to look for interesting codes and to investigate their properties. In this paper we present an alternative approach that uses computational analysis to accomplish the same goals. Specifically, we present an algorithm that computes the optimal quantum subsystem code that can be implemented given an arbitrary set of measurement operators that are tensor products of Pauli operators. We then demonstrate the utility of this algorithm by performing a systematic investigation of the quantum subsystem codes that exist in the setting where the interactions are limited to two-body interactions between neighbors on lattices derived from the convex uniform tilings of the plane.

  1. Advanced vehicle systems assessment. Volume 2: Subsystems assessment

    NASA Technical Reports Server (NTRS)

    Hardy, K.

    1985-01-01

    Volume 2 (Subsystems Assessment) is part of a five-volume report entitled Advanced Vehicle Systems Assessment. Volume 2 presents the projected performance capabilities and cost characteristics of applicable subsystems, considering an additional decade of development. Subsystems of interest include energy storage and conversion devices as well as the necessary powertrain components and vehicle subsystems. Volume 2 also includes updated battery information based on the assessment of an independent battery review board (with the aid of subcontractor reports on advanced battery characteristics).

  2. Analysis of Vital Subsystems of Technical System Maintenance

    DTIC Science & Technology

    1998-01-01

    fundamentals of logistic support for the technical system maintenance contained in and described by the basic maintance subsystems, have been presented in...this paper. The structure of the maintance system for major business was described throught the folloving subsystems: subsystem for the management of

  3. Digital Controller For Laser-Beam-Steering Subsystem: Part 2

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Voisinet, Leeann

    1995-01-01

    A report presents additional information about laser-beam-steering apparatus described in "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193) and "More About Beam-Steering Subsystem for Laser Communication" (NPO-19381). Reiterates basic principles of operation of beam-steering subsystem, with emphasis on modes of operation, basic design concepts, and initial experiments on partial prototype of apparatus.

  4. Automated biowaste sampling system urine subsystem operating model, part 1

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.; Mangialardi, J. K.; Rosen, F.

    1973-01-01

    The urine subsystem automatically provides for the collection, volume sensing, and sampling of urine from six subjects during space flight. Verification of the subsystem design was a primary objective of the current effort which was accomplished thru the detail design, fabrication, and verification testing of an operating model of the subsystem.

  5. Space-reactor electric systems: subsystem technology assessment

    SciTech Connect

    Anderson, R.V.; Bost, D.; Determan, W.R.

    1983-03-29

    This report documents the subsystem technology assessment. For the purpose of this report, five subsystems were defined for a space reactor electric system, and the report is organized around these subsystems: reactor; shielding; primary heat transport; power conversion and processing; and heat rejection. The purpose of the assessment was to determine the current technology status and the technology potentials for different types of the five subsystems. The cost and schedule needed to develop these potentials were estimated, and sets of development-compatible subsystems were identified.

  6. National Ignition Facility subsystem design requirements target area auxiliary subsystem SSDR 1.8.6

    SciTech Connect

    Reitz, T.

    1996-10-20

    This Subsystem Design Requirement (SSDR) establishes the performance, design, development, and test requirements for the Target Area Auxiliary Subsystems (WBS 1.8.6), which is part of the NIF Target Experimental System (WBS 1.8). This document responds directly to the requirements detailed in NIF Target Experimental System SDR 003 document. Key elements of the Target Area Auxiliary Subsystems include: WBS 1.8.6.1 Local Utility Services; WBS 1.8.6.2 Cable Trays; WBS 1.8.6.3 Personnel, Safety, and Occupational Access; WBS 1.8.6.4 Assembly, Installation, and Maintenance Equipment; WBS 1.8.6.4.1 Target Chamber Service System; WBS 1.8.6.4.2 Target Bay Service Systems.

  7. The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

    NASA Technical Reports Server (NTRS)

    Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

    1989-01-01

    The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

  8. SEP thrust subsystem performance sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Atkins, K. L.; Sauer, C. G., Jr.; Kerrisk, D. J.

    1973-01-01

    This is a two-part report on solar electric propulsion (SEP) performance sensitivity analysis. The first part describes the preliminary analysis of the SEP thrust system performance for an Encke rendezvous mission. A detailed description of thrust subsystem hardware tolerances on mission performance is included together with nominal spacecraft parameters based on these tolerances. The second part describes the method of analysis and graphical techniques used in generating the data for Part 1. Included is a description of both the trajectory program used and the additional software developed for this analysis. Part 2 also includes a comprehensive description of the use of the graphical techniques employed in this performance analysis.

  9. X-38 Bolt Retractor Subsystem Separation Demonstration

    NASA Technical Reports Server (NTRS)

    Rugless, Fedoria (Editor); Johnston, A. S.; Ahmed, R.; Garrison, J. C.; Gaines, J. L.; Waggoner, J. D.

    2002-01-01

    The Flight Robotics Laboratory FRL successfully demonstrated the X-38 bolt retractor subsystem (BRS). The BRS design was proven safe by testing in the Pyrotechnic Shock Facility (PSI) before being demonstrated in the FRL. This Technical Memorandum describes the BRS, FRL, PSF, and interface hardware. Bolt retraction time, spacecraft simulator acceleration, and a force analysis are also presented. The purpose of the demonstration was to show the FRL capability for spacecraft separation testing using pyrotechnics. Although a formal test was not performed due to schedule and budget constraints, the data will show that the BRS is a successful design concept and the FRL is suitable for future separation tests.

  10. Waves in space plasma dipole antenna subsystem

    NASA Technical Reports Server (NTRS)

    Thomson, Mark

    1993-01-01

    The Waves In Space Plasma (WISP) flight experiment requires a 50-meter-long deployable dipole antenna subsystem (DASS) to radiate radio frequencies from the STS Orbiter cargo bay. The transmissions are to excite outer ionospheric plasma between the dipole and a free-flying receiver (Spartan) for scientific purposes. This report describes the singular DASS design requirements and how the resulting design satisfies them. A jettison latch is described in some detail. The latch releases the antenna in case of any problems which might prevent the bay doors from closing for re-entry and landing of the Orbiter.

  11. High temperature superconducting digital circuits and subsystems

    SciTech Connect

    Martens, J.S.; Pance, A.; Whiteley, S.R.; Char, K.; Johansson, M.F.; Lee, L.; Hietala, V.M.; Wendt, J.R.; Hou, S.Y.; Phillips, J.

    1993-10-01

    The advances in the fabrication of high temperature superconducting devices have enabled the demonstration of high performance and useful digital circuits and subsystems. The yield and uniformity of the devices is sufficient for circuit fabrication at the medium scale integration (MSI) level with performance not seen before at 77 K. The circuits demonstrated to date include simple gates, counters, analog to digital converters, and shift registers. All of these are mid-sized building blocks for potential applications in commercial and military systems. The processes used for these circuits and blocks will be discussed along with observed performance data.

  12. Operation of the yield estimation subsystem

    NASA Technical Reports Server (NTRS)

    Mccrary, D. G.; Rogers, J. L.; Hill, J. D. (Principal Investigator)

    1979-01-01

    The organization and products of the yield estimation subsystem (YES) are described with particular emphasis on meteorological data acquisition, yield estimation, crop calendars, weekly weather summaries, and project reports. During the three phases of LACIE, YES demonstrated that it is possible to use the flow of global meteorological data and provide valuable information regarding global wheat production. It was able to establish a capability to collect, in a timely manner, detailed weather data from all regions of the world, and to evaluate and convert that data into information appropriate to the project's needs.

  13. Building the IOOS data management subsystem

    USGS Publications Warehouse

    de La Beaujardière, J.; Mendelssohn, R.; Ortiz, C.; Signell, R.

    2010-01-01

    We discuss progress to date and plans for the Integrated Ocean Observing System (IOOS??) Data Management and Communications (DMAC) subsystem. We begin by presenting a conceptual architecture of IOOS DMAC. We describe work done as part of a 3-year pilot project known as the Data Integration Framework and the subsequent assessment of lessons learned. We present work that has been accomplished as part of the initial version of the IOOS Data Catalog. Finally, we discuss near-term plans for augmenting IOOS DMAC capabilities.

  14. LARES Mission: Separation and Retention Subsystem

    NASA Technical Reports Server (NTRS)

    Bursi, Alessandro; Camilli, Pierluigi; Piredda, Claudio; Babini, Gianni; Mangraviti, Elio

    2014-01-01

    As part of the Lares (LAser RElativity Satellite) mission, an all-Italian scientific mission launched with the Vega maiden flight in February 2012, a mechanical separation and retention subsystem (SSEP) has been developed to retain the LARES satellite during launch and release it in the final orbit. The design flow was based on the identification of the driving requirements and critical areas to guide the trade-off, design, analysis and test activities. In particular, the SSEP had to face very high environmental loads and to minimize the contact areas with the satellite that had a spherical shape. The test activity overview is provided.

  15. Preprototype Vapor Compression Distillation Subsystem development

    NASA Technical Reports Server (NTRS)

    Thompson, C. D.; Ellis, G. S.; Schubert, F. H.

    1981-01-01

    Vapor Compression Distillation (VCD) has evolved as the most promising approach to reclaim potable water from wastewater for future long-term manned space missions. Life Systems, Inc. (LSI), working with NASA, has developed a preprototype Vapor Compression Distillation Subsystem (VCDS) which processes wastewater at 1.4 kg/h. The preprototype unit weighs 143 kg, occupies a volume of 0.47 cu m, and will reclaim 96 percent of the available wastewater. This unit has been tested by LSI and is scheduled for further testing at NASA-JSC. This paper presents the preprototype VCDS design, configuration, performance data, test results and flight system projections.

  16. Vacuum control subsystem for the Fermilab Tevatron

    SciTech Connect

    Zagel, J.R.; Chapman, L.J.

    1981-06-01

    The CAMAC 170 module and CIA crate provide a convenient, cost effective method of interfacing any system requiring a large number of simple devices to be multiplexed into the Accelerator Control System. The system is ideal for relatively slowly changing systems where ten bit analog to digital conversions are sufficiently accurate. Together with vacuum interface CIA cards and prom-based software resident in the 170, this system is used to provide intelligent local monitoring and control for the Tevatron vacuum subsystems. Although not implemented in the vacuum interface, digital to analog converters could be included on the plug in modules as well, providing a total digital and analog multiplexing scheme. 2 refs.

  17. UGV: security analysis of subsystem control network

    NASA Astrophysics Data System (ADS)

    Abbott-McCune, Sam; Kobezak, Philip; Tront, Joseph; Marchany, Randy; Wicks, Al

    2013-05-01

    Unmanned Ground vehicles (UGVs) are becoming prolific in the heterogeneous superset of robotic platforms. The sensors which provide odometry, localization, perception, and vehicle diagnostics are fused to give the robotic platform a sense of the environment it is traversing. The automotive industry CAN bus has dominated the industry due to the fault tolerance and the message structure allowing high priority messages to reach the desired node in a real time environment. UGVs are being researched and produced at an accelerated rate to preform arduous, repetitive, and dangerous missions that are associated with a military action in a protracted conflict. The technology and applications of the research will inevitably be turned into dual-use platforms to aid civil agencies in the performance of their various operations. Our motivation is security of the holistic system; however as subsystems are outsourced in the design, the overall security of the system may be diminished. We will focus on the CAN bus topology and the vulnerabilities introduced in UGVs and recognizable security vulnerabilities that are inherent in the communications architecture. We will show how data can be extracted from an add-on CAN bus that can be customized to monitor subsystems. The information can be altered or spoofed to force the vehicle to exhibit unwanted actions or render the UGV unusable for the designed mission. The military relies heavily on technology to maintain information dominance, and the security of the information introduced onto the network by UGVs must be safeguarded from vulnerabilities that can be exploited.

  18. Fault-tolerant multichannel demultiplexer subsystems

    NASA Technical Reports Server (NTRS)

    Redinbo, Robert

    1991-01-01

    Fault tolerance in future processing and switching communication satellites is addressed by showing new methods for detecting hardware failures in the first major subsystem, the multichannel demultiplexer. An efficient method for demultiplexing frequency slotted channels uses multirate filter banks which contain fast Fourier transform processing. All numerical processing is performed at a lower rate commensurate with the small bandwidth of each bandbase channel. The integrity of the demultiplexing operations is protected by using real number convolutional codes to compute comparable parity values which detect errors at the data sample level. High rate, systematic convolutional codes produce parity values at a much reduced rate, and protection is achieved by generating parity values in two ways and comparing them. Parity values corresponding to each output channel are generated in parallel by a subsystem, operating even slower and in parallel with the demultiplexer that is virtually identical to the original structure. These parity calculations may be time shared with the same processing resources because they are so similar.

  19. Electrochemical carbon dioxide concentrator subsystem development

    NASA Technical Reports Server (NTRS)

    Koszenski, E. P.; Heppner, D. B.; Bunnell, C. T.

    1986-01-01

    The most promising concept for a regenerative CO2 removal system for long duration manned space flight is the Electrochemical CO2 Concentrator (EDC), which allows for the continuous, efficient removal of CO2 from the spacecraft cabin. This study addresses the advancement of the EDC system by generating subsystem and ancillary component reliability data through extensive endurance testing and developing related hardware components such as electrochemical module lightweight end plates, electrochemical module improved isolation valves, an improved air/liquid heat exchanger and a triple redundant relative humidity sensor. Efforts included fabrication and testing the EDC with a Sabatier CO2 Reduction Reactor and generation of data necessary for integration of the EDC into a space station air revitalization system. The results verified the high level of performance, reliability and durability of the EDC subsystem and ancillary hardware, verified the high efficiency of the Sabatier CO2 Reduction Reactor, and increased the overall EDC technology engineering data base. The study concluded that the EDC system is approaching the hardware maturity levels required for space station deployment.

  20. PCM Passive Cooling System Containing Active Subsystems

    NASA Technical Reports Server (NTRS)

    Blanding, David E.; Bass, David I.

    2005-01-01

    A multistage system has been proposed for cooling a circulating fluid that is subject to intermittent intense heating. The system would be both flexible and redundant in that it could operate in a basic passive mode, either sequentially or simultaneously with operation of a first, active cooling subsystem, and either sequentially or simultaneously with a second cooling subsystem that could be active, passive, or a combination of both. This flexibility and redundancy, in combination with the passive nature of at least one of the modes of operation, would make the system more reliable, relative to a conventional cooling system. The system would include a tube-in-shell heat exchanger, within which the space between the tubes would be filled with a phase-change material (PCM). The circulating hot fluid would flow along the tubes in the heat exchanger. In the basic passive mode of operation, heat would be conducted from the hot fluid into the PCM, wherein the heat would be stored temporarily by virtue of the phase change.

  1. Local subsystems in gauge theory and gravity

    NASA Astrophysics Data System (ADS)

    Donnelly, William; Freidel, Laurent

    2016-09-01

    We consider the problem of defining localized subsystems in gauge theory and gravity. Such systems are associated to spacelike hypersurfaces with boundaries and provide the natural setting for studying entanglement entropy of localized subsystems. We present a general formalism to associate a gauge-invariant classical phase space to a spatial slice with boundary by introducing new degrees of freedom on the boundary. In Yang-Mills theory the new degrees of freedom are a choice of gauge on the boundary, transformations of which are generated by the normal component of the nonabelian electric field. In general relativity the new degrees of freedom are the location of a codimension-2 surface and a choice of conformal normal frame. These degrees of freedom transform under a group of surface symmetries, consisting of diffeomorphisms of the codimension-2 boundary, and position-dependent linear deformations of its normal plane. We find the observables which generate these symmetries, consisting of the conformal normal metric and curvature of the normal connection. We discuss the implications for the problem of defining entanglement entropy in quantum gravity. Our work suggests that the Bekenstein-Hawking entropy may arise from the different ways of gluing together two partial Cauchy surfaces at a cross-section of the horizon.

  2. Automating engineering verification in ALMA subsystems

    NASA Astrophysics Data System (ADS)

    Ortiz, José; Castillo, Jorge

    2014-08-01

    The Atacama Large Millimeter/submillimeter Array is an interferometer comprising 66 individual high precision antennas located over 5000 meters altitude in the north of Chile. Several complex electronic subsystems need to be meticulously tested at different stages of an antenna commissioning, both independently and when integrated together. First subsystem integration takes place at the Operations Support Facilities (OSF), at an altitude of 3000 meters. Second integration occurs at the high altitude Array Operations Site (AOS), where also combined performance with Central Local Oscillator (CLO) and Correlator is assessed. In addition, there are several other events requiring complete or partial verification of instrument specifications compliance, such as parts replacements, calibration, relocation within AOS, preventive maintenance and troubleshooting due to poor performance in scientific observations. Restricted engineering time allocation and the constant pressure of minimizing downtime in a 24/7 astronomical observatory, impose the need to complete (and report) the aforementioned verifications in the least possible time. Array-wide disturbances, such as global power interruptions and following recovery, generate the added challenge of executing this checkout on multiple antenna elements at once. This paper presents the outcome of the automation of engineering verification setup, execution, notification and reporting in ALMA and how these efforts have resulted in a dramatic reduction of both time and operator training required. Signal Path Connectivity (SPC) checkout is introduced as a notable case of such automation.

  3. Force protection demining system (FPDS) detection subsystem

    NASA Astrophysics Data System (ADS)

    Zachery, Karen N.; Schultz, Gregory M.; Collins, Leslie M.

    2005-06-01

    This study describes the U.S. Army Force Protection Demining System (FPDS); a remotely-operated, multisensor platform developed for reliable detection and neutralization of both anti-tank and anti-personnel landmines. The ongoing development of the prototype multisensor detection subsystem is presented, which integrates an advanced electromagnetic pulsed-induction array and ground penetrating synthetic aperture radar array on a single standoff platform. The FPDS detection subsystem is mounted on a robotic rubber-tracked vehicle and incorporates an accurate and precise navigation/positioning module making it well suited for operation in varied and irregular terrains. Detection sensors are optimally configured to minimize interference without loss in sensitivity or performance. Mine lane test data acquired from the prototype sensors are processed to extract signal- and image-based features for automatic target recognition. Preliminary results using optimal feature and classifier selection indicate the potential of the system to achieve high probabilities of detection while minimizing false alarms. The FPDS detection software system also exploits modern multi-sensor data fusion algorithms to provide real-time detection and discrimination information to the user.

  4. Development of an alkaline fuel cell subsystem

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A two task program was initiated to develop advanced fuel cell components which could be assembled into an alkaline power section for the Space Station Prototype (SSP) fuel cell subsystem. The first task was to establish a preliminary SSP power section design to be representative of the 200 cell Space Station power section. The second task was to conduct tooling and fabrication trials and fabrication of selected cell stack components. A lightweight, reliable cell stack design suitable for the SSP regenerative fuel cell power plant was completed. The design meets NASA's preliminary requirements for future multikilowatt Space Station missions. Cell stack component fabrication and tooling trials demonstrated cell components of the SSP stack design of the 1.0 sq ft area can be manufactured using techniques and methods previously evaluated and developed.

  5. Development of an alkaline fuel cell subsystem

    NASA Astrophysics Data System (ADS)

    1987-03-01

    A two task program was initiated to develop advanced fuel cell components which could be assembled into an alkaline power section for the Space Station Prototype (SSP) fuel cell subsystem. The first task was to establish a preliminary SSP power section design to be representative of the 200 cell Space Station power section. The second task was to conduct tooling and fabrication trials and fabrication of selected cell stack components. A lightweight, reliable cell stack design suitable for the SSP regenerative fuel cell power plant was completed. The design meets NASA's preliminary requirements for future multikilowatt Space Station missions. Cell stack component fabrication and tooling trials demonstrated cell components of the SSP stack design of the 1.0 sq ft area can be manufactured using techniques and methods previously evaluated and developed.

  6. NASA metrology information system: A NEMS subsystem

    NASA Technical Reports Server (NTRS)

    German, E. S., Jr.; Kern, F. A.; Yow, R. P.; Peterson, E.

    1984-01-01

    the NASA Metrology Information Systems (NMIS) is being developed as a standardized tool in managing the NASA field Center's instrument calibration programs. This system, as defined by the NASA Metrology and Calibration Workshop, will function as a subsystem of the newly developed NASA Equipment Management System (NEMS). The Metrology Information System is designed to utilize and update applicable NEMS data fields for controlled property and to function as a stand alone system for noncontrolled property. The NMIS provides automatic instrument calibration recall control, instrument historical performance data storage and analysis, calibration and repair labor and parts cost data, and instrument user and location data. Nineteen standardized reports were developed to analyze calibration system operations.

  7. Commissioning subsystems of the 10 meter prototype

    NASA Astrophysics Data System (ADS)

    Prins, Nathan; Fricke, Tobin; Mow-Lowry, Conor; Hanke, Manuela

    2015-04-01

    The best attempts at detecting the elusive gravitational waves are with L-shaped interferometers. Over the summer of 2014, I helped install subsystems of the 10 meter prototype, a gravitational wave interferometer designed to reach the Standard Quantum Limit (SQL), at the Max Planck Institute for Gravitational Physics in Hannover, Germany through the University of Florida's International REU. While there, the frequency reference cavity was aligned and the mode matching the cavity began. We also worked on installing and testing the intensity stabilization servo, which consisted of an out-of-vacuum photodiode for each the in-loop and out-of-loop sensing that were being connected to the LIGO Control and Data System.

  8. HYBRID FUEL CELL-SOLAR CELL SPACE POWER SUBSYSTEM CAPABILITY.

    DTIC Science & Technology

    This report outlines the capabilities and limitations of a hybrid solar cell- fuel cell space power subsystem by comparing the proposed hybrid system...to conventional power subsystem devices. The comparisons are based on projected 1968 capability in the areas of primary and secondary battery, fuel ... cell , solar cell, and chemical dynamic power subsystems. The purpose of the investigation was to determine the relative merits of a hybrid power

  9. Plant development, auxin, and the subsystem incompleteness theorem.

    PubMed

    Niklas, Karl J; Kutschera, Ulrich

    2012-01-01

    Plant morphogenesis (the process whereby form develops) requires signal cross-talking among all levels of organization to coordinate the operation of metabolic and genomic subsystems operating in a larger network of subsystems. Each subsystem can be rendered as a logic circuit supervising the operation of one or more signal-activated system. This approach simplifies complex morphogenetic phenomena and allows for their aggregation into diagrams of progressively larger networks. This technique is illustrated here by rendering two logic circuits and signal-activated subsystems, one for auxin (IAA) polar/lateral intercellular transport and another for IAA-mediated cell wall loosening. For each of these phenomena, a circuit/subsystem diagram highlights missing components (either in the logic circuit or in the subsystem it supervises) that must be identified experimentally if each of these basic plant phenomena is to be fully understood. We also illustrate the "subsystem incompleteness theorem," which states that no subsystem is operationally self-sufficient. Indeed, a whole-organism perspective is required to understand even the most simple morphogenetic process, because, when isolated, every biological signal-activated subsystem is morphogenetically ineffective.

  10. Giada improved calibration of measurement subsystems

    NASA Astrophysics Data System (ADS)

    Della Corte, V.; Rotundi, A.; Sordini, R.; Accolla, M.; Ferrari, M.; Ivanovski, S.; Lucarelli, F.; Mazzotta Epifani, E.; Palumbo, P.

    2014-12-01

    GIADA (Grain Impact Analyzer and Dust Accumulator) is an in-situ instrument devoted to measure the dynamical properties of the dust grains emitted by the comet. An Extended Calibration activity using the GIADA Flight Spare Model has been carried out taking into account the knowledge gained through the analyses of IDPs and cometary samples returned from comet 81P/Wild 2. GIADA consists of three measurement subsystems: Grain Detection System, an optical device measuring the optical cross-section for individual dust; Impact Sensor an aluminum plate connected to 5 piezo-sensors measuring the momentum of impacting single dust grains; Micro Balance System measuring the cumulative deposition in time of dust grains smaller than 10 μm. The results of the analyses on data acquired with the GIADA PFM and the comparison with calibration data acquired during the pre-launch campaign allowed us to improve GIADA performances and capabilities. We will report the results of the following main activities: a) definition of a correlation between the 2 GIADA Models (PFM housed in laboratory and In-Flight Model on-board ROSETTA); b) characterization of the sub-systems performances (signal elaboration, sensitivities, space environment effects); c) new calibration measurements and related curves by means of the PFM model using realistic cometary dust analogues. Acknowledgements: GIADA was built by a consortium led by the Univ. Napoli "Parthenope" & INAF-Oss. Astr. Capodimonte, IT, in collaboration with the Inst. de Astrofisica de Andalucia, ES, Selex-ES s.p.a. and SENER. GIADA is presently managed & operated by Ist. di Astrofisica e Planetologia Spaziali-INAF, IT. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with a support of the Spanish Ministry of Education and Science MEC, ES. GIADA was developed from a University of Kent, UK, PI proposal; sci. & tech. contribution given by CISAS, IT, Lab. d'Astr. Spat., FR, and Institutions from UK, IT, FR, DE and USA. We thank

  11. Does Normal Processing Provide Evidence of Specialised Semantic Subsystems?

    ERIC Educational Resources Information Center

    Shapiro, Laura R.; Olson, Andrew C.

    2005-01-01

    Category-specific disorders are frequently explained by suggesting that living and non-living things are processed in separate subsystems (e.g. Caramazza & Shelton, 1998). If subsystems exist, there should be benefits for normal processing, beyond the influence of structural similarity. However, no previous study has separated the relative…

  12. Triple redundant computer system/display and keyboard subsystem interface

    NASA Technical Reports Server (NTRS)

    Gulde, F. J.

    1973-01-01

    Interfacing of the redundant display and keyboard subsystem with the triple redundant computer system is defined according to space shuttle design. The study is performed in three phases: (1) TRCS configuration and characteristics identification; (2) display and keyboard subsystem configuration and characteristics identification, and (3) interface approach definition.

  13. The 30-centimeter ion thrust subsystem design manual

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The principal characteristics of the 30-centimeter ion propulsion thrust subsystem technology that was developed to satisfy the propulsion needs of future planetary and early orbital missions are described. Functional requirements and descriptions, interface and performance requirements, and physical characteristics of the hardware are described at the thrust subsystem, BIMOD engine system, and component level.

  14. Digital Controller For Laser-Beam-Steering Subsystem

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon

    1995-01-01

    Report presents additional information about proposed apparatus described in "Beam-Steering Subsystem for Laser Communication" (NPO-19069). Discusses design of digital beam-steering control subsystem and, in particular, that part of design pertaining to digital compensation for frequency response of steering mirror.

  15. Subsystem radiation susceptibility analysis for deep-space missions

    NASA Technical Reports Server (NTRS)

    West, W. S.; Poch, W.; Holmes-Siedle, A.; Bilsky, H. W.; Carroll, D.

    1971-01-01

    Scientific, unmanned spacecraft on mission to Jupiter and beyond will be subjected to nuclear radiation from the natural environment and onboard nuclear power sources which may be harmful to subsystems. This report postulates these environments and discusses practical considerations to ensure confidence that the spacecraft's materials and subsystems will withstand the effects of anticipated radiation. Degradation mechanisms are discussed.

  16. OVEN & LAVA Subsystems in the RESOLVE Payload for Resource Prospector

    NASA Technical Reports Server (NTRS)

    Captain, Janine E.

    2015-01-01

    A short briefing in Power Point of the status of the OVEN subsystem and the LAVA subsystems of the RESOLVE payload being developed under the Resource Prospector mission. The purpose of the mission is to sample and analyze volatile ices embedded in the lunar soil at the poles of the Moon and is expected to be conducted in the 2020 time frame.

  17. Development of a preprototype times wastewater recovery subsystem: Appendices

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.; Dehner, G. F.

    1984-01-01

    This Master Test Plan outlines the test program to be performed by Hamilton Standard during the Urine Water Recovery Subsystem Program. Testing is divided into three phases: (1) design support testing; development component testing; and acceptance testing. The completion of this test program verifies the subsystem operation.

  18. Double Shell Tank (DST) Monitor and Control Subsystem Definition Report

    SciTech Connect

    BAFUS, R.R.

    2000-03-16

    The system description of the Double-Shell Tank (DST) Monitor and Control Subsystem establishes the system boundaries and describes the interface of the DST Monitor and Control Subsystem with new and existing systems that are required to accomplish the Waste Feed Delivery (WFD) mission.

  19. Thermal energy storage subsystems. A collection of quarterly reports

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The design, development, and progress toward the delivery of three subsystems is discussed. The subsystem used a salt hydrate mixture for thermal energy storage. The program schedules, technical data, and other program activities from October 1, 1976, through December 31, 1977 are presented.

  20. Assessing Quality across Health Care Subsystems in Mexico

    PubMed Central

    Puig, Andrea; Pagán, José A.; Wong, Rebeca

    2012-01-01

    Recent healthcare reform efforts in Mexico have focused on the need to improve the efficiency and equity of a fragmented healthcare system. In light of these reform initiatives, there is a need to assess whether healthcare subsystems are effective at providing high-quality healthcare to all Mexicans. Nationally representative household survey data from the 2006 Encuesta Nacional de Salud y Nutrición (National Health and Nutrition Survey) were used to assess perceived healthcare quality across different subsystems. Using a sample of 7234 survey respondents, we found evidence of substantial heterogeneity in healthcare quality assessments across healthcare subsystems favoring private providers over social security institutions. These differences across subsystems remained even after adjusting for socioeconomic, demographic, and health factors. Our analysis suggests that improvements in efficiency and equity can be achieved by assessing the factors that contribute to heterogeneity in quality across subsystems. PMID:19305224

  1. Apollo experience report: Lunar module environmental control subsystem

    NASA Technical Reports Server (NTRS)

    Gillen, R. J.; Brady, J. C.; Collier, F.

    1972-01-01

    A functional description of the environmental control subsystem is presented. Development, tests, checkout, and flight experiences of the subsystem are discussed; and the design fabrication, and operational difficulties associated with the various components and subassemblies are recorded. Detailed information is related concerning design changes made to, and problems encountered with, the various elements of the subsystem, such as the thermal control water sublimator, the carbon dioxide sensing and control units, and the water section. The problems associated with water sterilization, water/glycol formulation, and materials compatibility are discussed. The corrective actions taken are described with the expection that this information may be of value for future subsystems. Although the main experiences described are problem oriented, the subsystem has generally performed satisfactorily in flight.

  2. Multi-Mission Automated Task Invocation Subsystem

    NASA Technical Reports Server (NTRS)

    Cheng, Cecilia S.; Patel, Rajesh R.; Sayfi, Elias M.; Lee, Hyun H.

    2009-01-01

    Multi-Mission Automated Task Invocation Subsystem (MATIS) is software that establishes a distributed data-processing framework for automated generation of instrument data products from a spacecraft mission. Each mission may set up a set of MATIS servers for processing its data products. MATIS embodies lessons learned in experience with prior instrument- data-product-generation software. MATIS is an event-driven workflow manager that interprets project-specific, user-defined rules for managing processes. It executes programs in response to specific events under specific conditions according to the rules. Because requirements of different missions are too diverse to be satisfied by one program, MATIS accommodates plug-in programs. MATIS is flexible in that users can control such processing parameters as how many pipelines to run and on which computing machines to run them. MATIS has a fail-safe capability. At each step, MATIS captures and retains pertinent information needed to complete the step and start the next step. In the event of a restart, this information is retrieved so that processing can be resumed appropriately. At this writing, it is planned to develop a graphical user interface (GUI) for monitoring and controlling a product generation engine in MATIS. The GUI would enable users to schedule multiple processes and manage the data products produced in the processes. Although MATIS was initially designed for instrument data product generation,

  3. Revealing Open Quantum Systems with Subsystem DFT

    NASA Astrophysics Data System (ADS)

    Krishtal, Alisa; Pavanello, Michele

    The traditional quantum chemical methods, wave function or density based, are designed to solve for a closed system, where the Hamiltonian contains all relevant interactions. The closed system is, however, not realistic, as in real life the system is embedded in an environment with which it interacts to some degree. Including the description of the environment at the full quantum mechanical level leads to the Open Quantum Systems (OQS) theory: the only theory which can describe non-Markovian dynamics between the system and the environment. By allowing the flow of information in both directions phenomena such as quantum entanglement, relevant for the design of quantum computers, become available. While most OQS theories rely on the density matrix to describe the system-bath interaction, time-dependent subsystem DFT allows to approach the problem using the electron density. Through Dyson-like equations connecting the density-density response kernels of the OQS and its environment, the extent to which non-Markovian dynamics is present can be revealed. We illustrate this for the process of excitation energy transfer in coupled chromophores embedded in explicit solvent.

  4. Synchronized target subsystem for automated docking systems

    NASA Technical Reports Server (NTRS)

    Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor)

    2000-01-01

    A synchronized target subsystem for use in an automated docking or station keeping system for docking a chase vehicle with a target vehicle wherein the chase vehicle is provided with a video camera which provides adjacent frames each having a predetermined time duration. A light source mounted on the target vehicle flashes at a frequency which has a time duration which is a multiple of the duration time of the frames, the light being on for at least one frame duration and being off for the remainder of the cycle. An image processing unit is connected to the camera for receiving signals from the camera and subtracting one of the adjacent frames from the other to detect whether the light appears in one frame, both frames or neither frame. If the target light appears in both frames or neither frame, the image processing unit feeds a signal to a timing circuit to advance the video camera one frame. This process is continued until the target light appears in one frame and not in the other, at which time the process of advancing the video camera is stopped.

  5. The CALIPSO Integrated Thermal Control Subsystem

    NASA Technical Reports Server (NTRS)

    Gasbarre, Joseph F.; Ousley, Wes; Valentini, Marc; Thomas, Jason; Dejoie, Joel

    2007-01-01

    The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) is a joint NASA-CNES mission to study the Earth's cloud and aerosol layers. The satellite is composed of a primary payload (built by Ball Aerospace) and a spacecraft platform bus (PROTEUS, built by Alcatel Alenia Space). The thermal control subsystem (TCS) for the CALIPSO satellite is a passive design utilizing radiators, multi-layer insulation (MLI) blankets, and both operational and survival surface heaters. The most temperature sensitive component within the satellite is the laser system. During thermal vacuum testing of the integrated satellite, the laser system's operational heaters were found to be inadequate in maintaining the lasers required set point. In response, a solution utilizing the laser system's survival heaters to augment the operational heaters was developed with collaboration between NASA, CNES, Ball Aerospace, and Alcatel-Alenia. The CALIPSO satellite launched from Vandenberg Air Force Base in California on April 26th, 2006. Evaluation of both the platform and payload thermal control systems show they are performing as expected and maintaining the critical elements of the satellite within acceptable limits.

  6. The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys

    DOE PAGES

    Wang, Zhangwei; Baker, Ian; Guo, Wei; ...

    2017-03-01

    We investigated the effects of cold rolling followed by annealing on the mechanical properties and dislocation substructure evolution of undoped and 1.1 at. % carbon-doped Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys (HEAs). X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom probe tomography (APT) were employed to characterize the microstructures. The as-cast HEAs were coarse-grained and single phase f.c.c., whereas the thermo-mechanical treatment caused recrystallization (to fine grain sizes) and precipitation (a B2 phase for the undoped HEA; and a B2 phase, and M23C6 and M7C3 carbides for the C-doped HEA). Carbon, which was found to have segregated tomore » the grain boundaries using APT, retarded recrystallization. The reduction in grain size resulted in a sharp increase in strength, while the precipitation, which produced only a small increase in strength, probably accounted for the small decrease in ductility for both undoped and C-doped HEAs. For both undoped and C-doped HEAs, the smaller grain-sized material initially exhibited higher strain hardening than the coarse-grained material but showed a much lower strain hardening at large tensile strains. Wavy slip in the undoped HEAs and planar slip in C-doped HEAs were found at the early stages of deformation irrespective of grain size. At higher strains, dislocation cell structures formed in the 19 μm grain-sized undoped HEA, while microbands formed in the 23 μm grain-sized C-doped HEA. Conversely, localized dislocation clusters were found in both HEAs at the finest grain sizes (5 μm). The inhibition of grain subdivision by the grain boundaries and precipitates lead to the transformation from regular dislocation configurations consisting of dislocation-cells and microbands to irregular dislocation configurations consisting of localized dislocation clusters, which further account for the decrease in ductility. Our investigation of the formation mechanism

  7. MSG Power Subsystem Flight Return Experience

    NASA Astrophysics Data System (ADS)

    Giacometti, G.; Canard, JP.; Perron, O.

    2011-10-01

    The Meteosat programme has been running for more than twenty years under ESA leadership. Meteosat Second Generation (MSG) is a series of 4 geostationary satellites developed and procured by the European Space Agency (ESA) on behalf of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Eumetsat is still operating two of the first generation satellites models named MOP3 and MTP1 which are pointed towards the Indian ocean. The European meteorological service is now enhanced by two spacecrafts of the Second Generation (MSG-1 and MSG-2). They have been launched by Ariane 5 in August 2002 and December 2005 respectively. Thales Alenia Space, Prime Contractor of the program, has developed the MSG spacecraft based on a spin-axis stabilized technology. The Electrical Power Subsystem was subcontracted to Astrium GmbH. The Solar Array is composed of 8 body mounted panels, based on Carbon Fibre Reinforced Panel substrate. The Solar network utilizes 7854 Silicon High Eta cells delivering a beginning of life power of 740W. The 28 volts mainbus is regulated using a series shunt regulating concept (S3R type). Two identical SAFT batteries, built from NiCd cells and offering a 29Ah nameplate capacity are connected to the mainbus through battery discharge and charge regulators. Both Solar Array and batteries have been designed to provide power and energy for a nominal 7 years lifetime. These equipments are continuously monitored and are still operating in excellent condition after more than eight and five years in orbit. This paper will present the major electrical design aspects of the power chain and will describe the main parameters performances, which are analysed during the in-orbit operations. Batteries ageing is detailed thanks to reconditioning processed telemetry while the solar array performances over lifetime use dedicated solar array telemetry.

  8. Shuttle Orbiter Active Thermal Control Subsystem design and flight experience

    NASA Technical Reports Server (NTRS)

    Bond, Timothy A.; Metcalf, Jordan L.; Asuncion, Carmelo

    1991-01-01

    The paper examines the design of the Space Shuttle Orbiter Active Thermal Control Subsystem (ATCS) constructed for providing the vehicle and payload cooling during all phases of a mission and during ground turnaround operations. The operation of the Shuttle ATCS and some of the problems encountered during the first 39 flights of the Shuttle program are described, with special attention given to the major problems encountered with the degradation of the Freon flow rate on the Orbiter Columbia, the Flash Evaporator Subsystem mission anomalies which occurred on STS-26 and STS-34, and problems encountered with the Ammonia Boiler Subsystem. The causes and the resolutions of these problems are discussed.

  9. Development of a preprototype vapor compression distillation water recovery subsystem

    NASA Technical Reports Server (NTRS)

    Johnson, K. L.

    1978-01-01

    The activities involved in the design, development, and test of a preprototype vapor compression distillation water recovery subsystem are described. This subsystem, part of a larger regenerative life support evaluation system, is designed to recover usable water from urine, urinal rinse water, and concentrated shower and laundry brine collected from three space vehicle crewmen for a period of 180 days without resupply. Details of preliminary design and testing as well as component developments are included. Trade studies, considerations leading to concept selections, problems encountered, and test data are also presented. The rework of existing hardware, subsystem development including computer programs, assembly verification, and comprehensive baseline test results are discussed.

  10. Subsystem response review. Seismic Safety Margins Research Program

    SciTech Connect

    Kennedy, R. P.; Campbell, R. D.; Wesley, D. A.; Kamil, H.; Gantayat, A.; Vasudevan, R.

    1981-02-01

    A study was conducted to document the state of the art in seismic qualification of nuclear power plant components and subsystems by analysis and testing and to identify the sources and magnitude of the uncertainties associated with analysis and testing methods. The uncertainties are defined in probabilistic terms for use in probabilistic seismic risk studies. Recommendations are made for the most appropriate subsystem response analysis methods to minimize response uncertainties. Additional studies, to further quantify testing uncertainties, are identified. Although the general effect of non-linearities on subsystem response is discussed, recommendations and conclusions are based principally on linear elastic analysis and testing models.

  11. Development of a preprototype times wastewater recovery subsystem

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.; Dehner, G. F.

    1982-01-01

    A three-man wastewater recovery preprototype subsystem using a hollow fiber membrane evaporator with a thermoelectric heat pump to provide efficient potable water recovery from wastewater on extended duration space flights was designed, fabricated, and tested at one-gravity. Low power, compactness and gravity insensitive operation are featured in this vacuum distillation subsystem. The tubular hollow fiber elements provide positive liquid/gas phase control with no moving parts, and provide structural integrity, improving on previous flat sheet membrane designs. A thermoelectric heat pump provides latent energy recovery. Application and integration of these key elements solved problems inherent in all previous reclamation subsystem designs.

  12. Simulation verification techniques study. Subsystem simulation validation techniques

    NASA Technical Reports Server (NTRS)

    Duncan, L. M.; Reddell, J. P.; Schoonmaker, P. B.

    1974-01-01

    Techniques for validation of software modules which simulate spacecraft onboard systems are discussed. An overview of the simulation software hierarchy for a shuttle mission simulator is provided. A set of guidelines for the identification of subsystem/module performance parameters and critical performance parameters are presented. Various sources of reference data to serve as standards of performance for simulation validation are identified. Environment, crew station, vehicle configuration, and vehicle dynamics simulation software are briefly discussed from the point of view of their interfaces with subsystem simulation modules. A detailed presentation of results in the area of vehicle subsystems simulation modules is included. A list of references, conclusions and recommendations are also given.

  13. Space shuttle atmospheric revitalization subsystem/active thermal control subsystem computer program (users manual)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A shuttle (ARS) atmosphere revitalization subsystem active thermal control subsystem (ATCS) performance routine was developed. This computer program is adapted from the Shuttle EC/LSS Design Computer Program. The program was upgraded in three noteworthy areas: (1) The functional ARS/ATCS schematic has been revised to accurately synthesize the shuttle baseline system definition. (2) The program logic has been improved to provide a more accurate prediction of the integrated ARS/ATCS system performance. Additionally, the logic has been expanded to model all components and thermal loads in the ARS/ATCS system. (3) The program is designed to be used on the NASA JSC crew system division's programmable calculator system. As written the new computer routine has an average running time of five minutes. The use of desk top type calculation equipment, and the rapid response of the program provides the NASA with an analytical tool for trade studies to refine the system definition, and for test support of the RSECS or integrated Shuttle ARS/ATCS test programs.

  14. Apollo experience report: Command and service module controls and displays subsystem

    NASA Technical Reports Server (NTRS)

    Olsen, A. B.; Swint, R. J.

    1976-01-01

    A review of the command and service module controls and displays subsystem is presented. The subsystem is described, and operational requirements, component history, problems and solutions, and conclusions and recommendations for the subsystem are included.

  15. Development of Pattern Recognition Options for Combining Safeguards Subsystems

    SciTech Connect

    Burr, Thomas L.; Hamada, Michael S.

    2012-08-24

    This talk reviews project progress in combining process monitoring data and nuclear material accounting data to improve the over nuclear safeguards system. Focus on 2 subsystems: (1) nuclear materials accounting (NMA); and (2) process monitoring (PM).

  16. Development status of a preprototype water electrolysis subsystem

    NASA Technical Reports Server (NTRS)

    Martin, R. B.; Erickson, A. C.

    1981-01-01

    A preprototype water electrolysis subsystem was designed and fabricated for NASA's advanced regenerative life support program. A solid polymer is used for the cell electrolyte. The electrolysis module has 12 cells that can generate 5.5 kg/day of oxygen for the metabolic requirements of three crewmembers, for cabin leakage, and for the oxygen and hydrogen required for carbon dioxide collection and reduction processes. The subsystem can be operated at a pressure between 276 and 2760 kN/sq m and in a continuous constant-current, cyclic, or standby mode. A microprocessor is used to aid in operating the subsystem. Sensors and controls provide fault detection and automatic shutdown. The results of development, demonstration, and parametric testing are presented. Modifications to enhance operation in an integrated and manned test are described. Prospective improvements for the electrolysis subsystem are discussed.

  17. Implementation of the radio science subsystem in the DSN

    NASA Technical Reports Server (NTRS)

    Kimball, K. R.

    1978-01-01

    The functional characteristics of a subsystem for support of radio science data acquisition requirements are described. The factors that were of major importance in the design and implementation approach are considered.

  18. Pilot climate data system: User's guide for charts subsystem

    NASA Technical Reports Server (NTRS)

    Noll, C. E.

    1984-01-01

    The use of the Pilot Climate Data System's (PCDS) CHARTS Subsystem is described. This facility is an interactive software system for the graphical production and enhancement of text and viewgraph displays.

  19. Double Shell Tank (DST) Monitor and Control Subsystem Specification

    SciTech Connect

    BAFUS, R.R.

    2000-11-03

    This specification revises the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Monitor and Control Subsystem that supports the first phase of Waste Feed Delivery.

  20. Double Shell Tank (DST) Process Waste Sampling Subsystem Specification

    SciTech Connect

    RASMUSSEN, J.H.

    2000-05-03

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied to the Double-Shell Tank (DST) Process Waste Sampling Subsystem which supports the first phase of Waste Feed Delivery.

  1. Ice pack heat sink subsystem - phase 1, volume 2

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.

    1973-01-01

    The design, development, and test of a functional laboratory model ice pack heat sink subsystem are discussed. Operating instructions to include mechanical and electrical schematics, maintenance instructions, and equipment specifications are presented.

  2. Automated Subsystem Control for Life Support System (ASCLSS)

    NASA Technical Reports Server (NTRS)

    Block, Roger F.

    1987-01-01

    The Automated Subsystem Control for Life Support Systems (ASCLSS) program has successfully developed and demonstrated a generic approach to the automation and control of space station subsystems. The automation system features a hierarchical and distributed real-time control architecture which places maximum controls authority at the lowest or process control level which enhances system autonomy. The ASCLSS demonstration system pioneered many automation and control concepts currently being considered in the space station data management system (DMS). Heavy emphasis is placed on controls hardware and software commonality implemented in accepted standards. The approach demonstrates successfully the application of real-time process and accountability with the subsystem or process developer. The ASCLSS system completely automates a space station subsystem (air revitalization group of the ASCLSS) which moves the crew/operator into a role of supervisory control authority. The ASCLSS program developed over 50 lessons learned which will aide future space station developers in the area of automation and controls..

  3. MIUS Integration and Subsystem Test (MIST) data system

    NASA Technical Reports Server (NTRS)

    Pringle, L. M.

    1977-01-01

    A data system for use in testing integrated subsystems of a modular integrated utility system (MIUS) is presented. The MIUS integration and subsystem test (MIST) data system is reviewed from its conception through its checkout and operation as the controlling portion of the MIST facility. The MIST data system provides a real time monitoring and control function that allows for complete evaluation of the performance of the mechanical and electrical subsystems, as well as controls the operation of the various components of the system. In addition to the aforementioned capabilities, the MIST data system provides computerized control of test operations such that minimum manpower is necessary to set up, operate, and shut down subsystems during test periods.

  4. Double Shell Tank (DST) Transfer Piping Subsystem Specification

    SciTech Connect

    GRAVES, C.E.

    2001-01-17

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Transfer Piping Subsystem that supports the first phase of Waste Feed Delivery.

  5. Double Shell Tank (DST) Diluent and Flush Subsystem Specification

    SciTech Connect

    GRAVES, C.E.

    2001-01-18

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied to the Double-Shell Tank (DST) Diluent and Flush Subsystem which supports the first phase of Waste Feed Delivery.

  6. Automated biowaste sampling system, solids subsystem operating model, part 2

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.; Mangialardi, J. K.; Stauffer, R. E.

    1973-01-01

    The detail design and fabrication of the Solids Subsystem were implemented. The system's capacity for the collection, storage or sampling of feces and vomitus from six subjects was tested and verified.

  7. Opto-mechanical subsystem with temperature compensation through isothemal design

    NASA Technical Reports Server (NTRS)

    Goodwin, F. E. (Inventor)

    1977-01-01

    An opto-mechanical subsystem for supporting a laser structure which minimizes changes in the alignment of the laser optics in response to temperature variations is described. Both optical and mechanical structural components of the system are formed of the same material, preferably beryllium, which is selected for high mechanical strength and good thermal conducting qualities. All mechanical and optical components are mounted and assembled to provide thorough thermal coupling throughout the subsystem to prevent the development of temperature gradients.

  8. Multilevel control optimization using subsystem relative performance index sensitivity

    NASA Technical Reports Server (NTRS)

    Leininger, G. G.; Lehtinen, F. B.

    1974-01-01

    A method is presented for the design of optimal feedback controllers for large multivariable systems with subsystem sensitivity constraints. The weighted sum of subsystem and/or operational mode relative performance index sensitivities is defined as the overall performance index. The method is developed for linear systems with quadratic performance criteria and either full or partial state feedback. An example concerning the design of a stability augmentation system for a VTOL aircraft in the transition mode demonstrates the effectiveness of the design method.

  9. Prototype Bosch CO2 reduction subsystem for the RLSE experiment

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Wynveen, R. A.; Schubert, F. H.

    1977-01-01

    Requirements for the Bosch carbon dioxide reduction subsystem were established in a study of regenerative life support evaluation experiments. A detailed design is presented including a schematic, components list and characteristics, requirements summaries, and complete definition of life systems' advanced control/monitor instrumentation applied to the Bosch subsystem. Design information needed to proceed with the final design and fabrication of a preprototype system is presented.

  10. STS-2: SAIL non-avionics subsystems math model requirements

    NASA Technical Reports Server (NTRS)

    Bennett, W. P.; Herold, R. W.

    1980-01-01

    Simulation of the STS-2 Shuttle nonavionics subsystems in the shuttle avionics integration laboratory (SAIL) is necessary for verification of the integrated shuttle avionics system. The math model (simulation) requirements for each of the nonavionics subsystems that interfaces with the Shuttle avionics system is documented and a single source document for controlling approved changes (by the SAIL change control panel) to the math models is provided.

  11. Power Subsystem for Extravehicular Activities for Exploration Missions

    NASA Technical Reports Server (NTRS)

    Manzo, Michelle

    2005-01-01

    The NASA Glenn Research Center has the responsibility to develop the next generation space suit power subsystem to support the Vision for Space Exploration. Various technology challenges exist in achieving extended duration missions as envisioned for future lunar and Mars mission scenarios. This paper presents an overview of ongoing development efforts undertaken at the Glenn Research Center in support of power subsystem development for future extravehicular activity systems.

  12. Technology for subsystems of space-based plant growth facilities

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Morrow, R. C.; Tibbitts, T. W.; Corey, R. B.

    1990-01-01

    Technologies for different subsystems of space-based plant growth facilities are being developed at the Wisconsin Center for Space Automation and Robotics, a NASA Center for the Commercial Development of Space. The technologies include concepts for water and nutrient delivery, for nutrient composition control, and for irradiation. Effort is being concentrated on these subsystems because available technologies cannot be effectively utilized for space applications.

  13. Statistical Design Model (SDM) of satellite thermal control subsystem

    NASA Astrophysics Data System (ADS)

    Mirshams, Mehran; Zabihian, Ehsan; Aarabi Chamalishahi, Mahdi

    2016-07-01

    Satellites thermal control, is a satellite subsystem that its main task is keeping the satellite components at its own survival and activity temperatures. Ability of satellite thermal control plays a key role in satisfying satellite's operational requirements and designing this subsystem is a part of satellite design. In the other hand due to the lack of information provided by companies and designers still doesn't have a specific design process while it is one of the fundamental subsystems. The aim of this paper, is to identify and extract statistical design models of spacecraft thermal control subsystem by using SDM design method. This method analyses statistical data with a particular procedure. To implement SDM method, a complete database is required. Therefore, we first collect spacecraft data and create a database, and then we extract statistical graphs using Microsoft Excel, from which we further extract mathematical models. Inputs parameters of the method are mass, mission, and life time of the satellite. For this purpose at first thermal control subsystem has been introduced and hardware using in the this subsystem and its variants has been investigated. In the next part different statistical models has been mentioned and a brief compare will be between them. Finally, this paper particular statistical model is extracted from collected statistical data. Process of testing the accuracy and verifying the method use a case study. Which by the comparisons between the specifications of thermal control subsystem of a fabricated satellite and the analyses results, the methodology in this paper was proved to be effective. Key Words: Thermal control subsystem design, Statistical design model (SDM), Satellite conceptual design, Thermal hardware

  14. Operating executive for the DSIF tracking subsystem software

    NASA Technical Reports Server (NTRS)

    Poulson, P. L.

    1972-01-01

    The advanced engineering model of the DSIF tracking subsystem (DTS) is being developed by the Deep Space Instrumentation Facility. The DTS will provide effective and reliable tracking and data acquisition support for the complex planetary and interplanetary space flight missions planned for the 1970's. The nucleus of the subsystem is a Honeywell H832 digital computer. The design and capabilities of the real-time operating executive software are described.

  15. Double Shell Tank (DST) Maintenance and Recovery Subsystem Definition Report

    SciTech Connect

    SMITH, E.A.

    2000-07-26

    The description of the Double-Shell Tank (DST) Maintenance and Recovery Subsystem presented in this document was developed to establish its boundaries. The DST Maintenance and Recovery Subsystem consists of new and existing equipment and facilities used to provide tank farm operators logistic support and problem resolution for the DST System during operations. This support will include evaluating equipment status, performing preventive and corrective maintenance, developing work packages, managing spares and consumables, supplying tooling, and training maintenance and operations personnel.

  16. Software For Real-Time Simulation Of Subsystems

    NASA Technical Reports Server (NTRS)

    Favors, Dwight A.; Devoss, Dan; Cheatham, Michael

    1995-01-01

    The Real-Time Software Simulation of Small Imbedded System (SSO) computer program developed for use in simulating number of systems and subsystems of space shuttle Columbia. These systems and subsystems include system control module (SCM), ground support equipment and test assembly (GSE/TA), and support system for orbiter experiments (OEX). Consists of SCM, orbiter experiments tape recorder, and orbiter experiments pulse-code-modulation (PCM) data system. Consists of four subprograms written in C language.

  17. An Algorithm for Integrated Subsystem Embodiment and System Synthesis

    NASA Technical Reports Server (NTRS)

    Lewis, Kemper

    1997-01-01

    Consider the statement,'A system has two coupled subsystems, one of which dominates the design process. Each subsystem consists of discrete and continuous variables, and is solved using sequential analysis and solution.' To address this type of statement in the design of complex systems, three steps are required, namely, the embodiment of the statement in terms of entities on a computer, the mathematical formulation of subsystem models, and the resulting solution and system synthesis. In complex system decomposition, the subsystems are not isolated, self-supporting entities. Information such as constraints, goals, and design variables may be shared between entities. But many times in engineering problems, full communication and cooperation does not exist, information is incomplete, or one subsystem may dominate the design. Additionally, these engineering problems give rise to mathematical models involving nonlinear functions of both discrete and continuous design variables. In this dissertation an algorithm is developed to handle these types of scenarios for the domain-independent integration of subsystem embodiment, coordination, and system synthesis using constructs from Decision-Based Design, Game Theory, and Multidisciplinary Design Optimization. Implementation of the concept in this dissertation involves testing of the hypotheses using example problems and a motivating case study involving the design of a subsonic passenger aircraft.

  18. NFIRAOS in 2015: engineering for future integration of complex subsystems

    NASA Astrophysics Data System (ADS)

    Atwood, Jenny; Andersen, David; Byrnes, Peter; Densmore, Adam; Fitzsimmons, Joeleff; Herriot, Glen; Hill, Alexis

    2016-07-01

    The Narrow Field InfraRed Adaptive Optics System (NFIRAOS) will be the first-light facility Adaptive Optics (AO) system for the Thirty Meter Telescope (TMT). NFIRAOS will be able to host three science instruments that can take advantage of this high performance system. NRC Herzberg is leading the design effort for this critical TMT subsystem. As part of the final design phase of NFIRAOS, we have identified multiple subsystems to be sub-contracted to Canadian industry. The scope of work for each subcontract is guided by the NFIRAOS Work Breakdown Structure (WBS) and is divided into two phases: the completion of the final design and the fabrication, assembly and delivery of the final product. Integration of the subsystems at NRC will require a detailed understanding of the interfaces between the subsystems, and this work has begun by defining the interface physical characteristics, stability, local coordinate systems, and alignment features. In order to maintain our stringent performance requirements, the interface parameters for each subsystem are captured in multiple performance budgets, which allow a bottom-up error estimate. In this paper we discuss our approach for defining the interfaces in a consistent manner and present an example error budget that is influenced by multiple subsystems.

  19. Double Shell Tank (DST) Monitor and Control Subsystem Specification

    SciTech Connect

    BAFUS, R.R.

    2000-04-27

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Monitor and Control Subsystem that supports the first phase of Waste Feed Delivery. This subsystem specification establishes the interface and performance requirements and provides references to the requisite codes and standards to be applied during the design of the Double-Shell Tank (DST) Monitor and Control Subsystem. The DST Monitor and Control Subsystem consists of the new and existing equipment that will be used to provide tank farm operators with integrated local monitoring and control of the DST systems to support Waste Feed Delivery (WFD). New equipment will provide automatic control and safety interlocks where required and provide operators with visibility into the status of DST subsystem operations (e.g., DST mixer pump operation and DST waste transfers) and the ability to manually control specified DST functions as necessary. This specification is intended to be the basis for new project/installations (W-521, etc.). This specification is not intended to retroactively affect previously established project design criteria without specific direction by the program.

  20. Preprototype vapor compression distillation subsystem. [recovering potable water from wastewater

    NASA Technical Reports Server (NTRS)

    Ellis, G. S.; Wynveen, R. A.; Schubert, F. H.

    1979-01-01

    A three-person capacity preprototype vapor compression distillation subsystem for recovering potable water from wastewater aboard spacecraft was designed, assembled, and tested. The major components of the subsystem are: (1) a distillation unit which includes a compressor, centrifuge, central shaft, and outer shell; (2) a purge pump; (3) a liquids pump; (4) a post-treat cartridge; (5) a recycle/filter tank; (6) an evaporator high liquid level sensor; and (7) the product water conductivity monitor. A computer based control monitor instrumentation carries out operating mode change sequences, monitors and displays subsystem parameters, maintains intramode controls, and stores and displays fault detection information. The mechanical hardware occupies 0.467 m3, requires 171 W of electrical power, and has a dry weight of 143 kg. The subsystem recovers potable water at a rate of 1.59 kg/hr, which is equivalent to a duty cycle of approximately 30% for a crew of three. The product water has no foul taste or odor. Continued development of the subsystem is recommended for reclaiming water for human consumption as well as for flash evaporator heat rejection, urinal flushing, washing, and other on-board water requirements.

  1. Safe Operation of HIFI Local Oscillator Subsystem on Herschel Mission

    NASA Astrophysics Data System (ADS)

    Michalska, Malgorzata; Juchnikowski, Grzegorz; Klein, Thomas; Leinz, Christian; Nowosielski, Witold; Orleanski, Piotr; Ward, John

    The HIFI Local Oscillator Subsystem is part of the Heterodyne Instrument for Far Infrared (HIFI) dedicated for astronomical observations,to be mounted on the ESA satellite HER- SCHEL. The Subsystem provides the local oscillator signal (480-1910 GHz) to each of the fourteen HIFI input mixers. Part of LO, the Local Oscillator Control Unit (LCU) provides the main interface between Local Oscillator Subsystem and HIFI/Herschel power and telemetry buses. The unit supplies Local Oscillator, decodes the HIFI macro-commands, programs and monitors the parameters of Ka-Band Synthesizer and THz multiplier chains and controls the operation of the whole Local Oscillator Subsystem. The unique microwave components used in HF multipliers are extremely sensitive to the proper biasing (polarity, voltage, current, presence of HF power).The ESA strategy of this mission requires full safe operation of the instrument. This requirements is covered by complex protection system implemented inside LCU. In this paper, we present the general overview of the protection system of microwave components. The different levels of protection (hardware realization and software procedures) are described as well as various reliability aspects. The functionality of LO subsystem controlled by LCU was tested in 2007. Now the flight model of HIFI instrument is integrated with the satellite and will be launched with Herschel mission in July 2008.

  2. Differential coding by two olfactory subsystems in the honeybee brain.

    PubMed

    Carcaud, Julie; Hill, Thomas; Giurfa, Martin; Sandoz, Jean-Christophe

    2012-08-01

    Sensory systems use parallel processing to extract and process different features of environmental stimuli. Parallel processing has been studied in the auditory, visual, and somatosensory systems, but equivalent research in the olfactory modality is scarce. The honeybee Apis mellifera is an interesting model for such research as its relatively simple brain contains a dual olfactory system, with a clear neural dichotomy from the periphery to higher-order centers, based on two main neuronal tracts [medial (m) and lateral (l) antenno-protocerebral tract (APT)]. The function of this dual system is as yet unknown, and attributes like odor quality and odor quantity might be separately encoded in these subsystems. We have thus studied olfactory coding at the input of both subsystems, using in vivo calcium imaging. As one of the subsystems (m-APT) has never been imaged before, a novel imaging preparation was developed to this end, and responses to a panel of aliphatic odorants at different concentrations were compared in both subsystems. Our data show a global redundancy of olfactory coding at the input of both subsystems but unravel some specificities for encoding chemical group and carbon chain length of odor molecules.

  3. The complete Heyting algebra of subsystems and contextuality

    NASA Astrophysics Data System (ADS)

    Vourdas, A.

    2013-08-01

    The finite set of subsystems of a finite quantum system with variables in {{Z}}(n), is studied as a Heyting algebra. The physical meaning of the logical connectives is discussed. It is shown that disjunction of subsystems is more general concept than superposition. Consequently, the quantum probabilities related to commuting projectors in the subsystems, are incompatible with associativity of the join in the Heyting algebra, unless if the variables belong to the same chain. This leads to contextuality, which in the present formalism has as contexts, the chains in the Heyting algebra. Logical Bell inequalities, which contain "Heyting factors," are discussed. The formalism is also applied to the infinite set of all finite quantum systems, which is appropriately enlarged in order to become a complete Heyting algebra.

  4. The definition of input parameters for modelling of energetic subsystems

    NASA Astrophysics Data System (ADS)

    Ptacek, M.

    2013-06-01

    This paper is a short review and a basic description of mathematical models of renewable energy sources which present individual investigated subsystems of a system created in Matlab/Simulink. It solves the physical and mathematical relationships of photovoltaic and wind energy sources that are often connected to the distribution networks. The fuel cell technology is much less connected to the distribution networks but it could be promising in the near future. Therefore, the paper informs about a new dynamic model of the low-temperature fuel cell subsystem, and the main input parameters are defined as well. Finally, the main evaluated and achieved graphic results for the suggested parameters and for all the individual subsystems mentioned above are shown.

  5. Mathematical modeling of control subsystems for CELSS: Application to diet

    NASA Technical Reports Server (NTRS)

    Waleh, Ahmad; Nguyen, Thoi K.; Kanevsky, Valery

    1991-01-01

    The dynamic control of a Closed Ecological Life Support System (CELSS) in a closed space habitat is of critical importance. The development of a practical method of control is also a necessary step for the selection and design of realistic subsystems and processors for a CELSS. Diet is one of the dynamic factors that strongly influences, and is influenced, by the operational states of all major CELSS subsystems. The problems of design and maintenance of a stable diet must be obtained from well characterized expert subsystems. The general description of a mathematical model that forms the basis of an expert control program for a CELSS is described. The formulation is expressed in terms of a complete set of time dependent canonical variables. System representation is dynamic and includes time dependent storage buffers. The details of the algorithm are described. The steady state results of the application of the method for representative diets made from wheat, potato, and soybean are presented.

  6. Double Shell Tank (DST) Transfer Piping Subsystem Specification

    SciTech Connect

    GRAVES, C.E.

    2000-03-22

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Transfer Piping Subsystem that supports the first phase of Waste Feed Delivery. This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Transfer Piping Subsystem that supports the first phase of waste feed delivery. This subsystem transfers waste between transfer-associated structures (pits) and to the River Protection Project (RPP) Privatization Contractor Facility where it will be processed into an immobilized waste form. This specification is intended to be the basis for new projects/installations (W-521, etc.). This specification is not intended to retroactively affect previously established project design criteria without specific direction by the program.

  7. The complete Heyting algebra of subsystems and contextuality

    SciTech Connect

    Vourdas, A.

    2013-08-15

    The finite set of subsystems of a finite quantum system with variables in Z(n), is studied as a Heyting algebra. The physical meaning of the logical connectives is discussed. It is shown that disjunction of subsystems is more general concept than superposition. Consequently, the quantum probabilities related to commuting projectors in the subsystems, are incompatible with associativity of the join in the Heyting algebra, unless if the variables belong to the same chain. This leads to contextuality, which in the present formalism has as contexts, the chains in the Heyting algebra. Logical Bell inequalities, which contain “Heyting factors,” are discussed. The formalism is also applied to the infinite set of all finite quantum systems, which is appropriately enlarged in order to become a complete Heyting algebra.

  8. Modular thrust subsystem approaches to solar electric propulsion module design

    NASA Technical Reports Server (NTRS)

    Cake, J. E.; Sharp, G. R.; Oglebay, J. C.; Shaker, F. J.; Zevesky, R. J.

    1976-01-01

    Three approaches are presented for packaging the elements of a 30 cm ion thrustor subsystem into a modular thrust subsystem. The individual modules, when integrated into a conceptual solar electric propulsion module are applicable to a multimission set of interplanetary flights with the Space Shuttle/Interim Upper Stage as the launch vehicle. The emphasis is on the structural and thermal integration of the components into the modular thrust subsystems. Thermal control for the power processing units is either by direct radiation through louvers in combination with heat pipes of an all heat pipe system. The propellant storage and feed system and thrustor gimbal system concepts are presented. The three approaches are compared on the basis of mass, cost, testing, interfaces, simplicity, reliability, and maintainability.

  9. Ice pack heat sink subsystem - Phase 1, Volume 1

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.

    1973-01-01

    The design, development, fabrication, and test at one-g of a functional laboratory model (non-flight) ice pack heat sink subsystem to be used eventually for astronaut cooling during manned space missions are discussed. In normal use, excess heat in the liquid cooling garment (LCG) coolant is transferred to a reusable/regenerable ice pack heat sink. For emergency operation, or for extension of extravehicular activity mission time after all the ice has melted, water from the ice pack is boiled to vacuum, thereby continuing to remove heat from the LCG coolant. This subsystem incorporates a quick connect/disconnect thermal interface between the ice pack heat sink and the subsystem heat exchanger.

  10. Controlling chaos in a satellite power supply subsystem

    NASA Astrophysics Data System (ADS)

    Macau, E. E. N.; Ramos Turci, L. F.; Yoneyama, T.

    2008-12-01

    In this work, we show that chaos control techniques can be used to increase the region that can be efficiently used to supply the power requests for an artificial satellite. The core of a satellite power subsystem relies on its DC/DC converter. This is a very nonlinear system that presents a multitude of phenomena ranging from bifurcations, quasi-periodicity, chaos, coexistence of attractors, among others. The traditional power subsystem design techniques try to avoid these nonlinear phenomena so that it is possible to use linear system theory in small regions about the equilibrium points. Here, we show that chaos control can be used to efficiently extend the applicability region of the satellite power subsystem when it operates in regions of high nonlinearity.

  11. Modular thrust subsystem approaches to solar electric propulsion module design

    NASA Technical Reports Server (NTRS)

    Cake, J. E.; Sharp, G. R.; Oglebay, J. C.; Shaker, F. J.; Zavesky, R. J.

    1976-01-01

    Three approaches are presented for packaging the elements of a 30 cm ion thruster subsystem into a modular thrust subsystem. The individual modules, when integrated into a conceptual solar electric propulsion module are applicable to a multimission set of interplanetary flights with the space shuttle interim upper stage as the launch vehicle. The emphasis is on the structural and thermal integration of the components into the modular thrust subsystems. Thermal control for the power processing units is either by direct radiation through louvers in combination with heat pipes or an all heat pipe system. The propellant storage and feed system and thruster gimbal system concepts are presented. The three approaches are compared on the basis of mass, cost, testing, interfaces, simplicity, reliability, and maintainability.

  12. Virtual Engineering and Science Team - Reusable Autonomy for Spacecraft Subsystems

    NASA Technical Reports Server (NTRS)

    Bailin, Sidney C.; Johnson, Michael A.; Rilee, Michael L.; Truszkowski, Walt; Thompson, Bryan; Day, John H. (Technical Monitor)

    2002-01-01

    In this paper we address the design, development, and evaluation of the Virtual Engineering and Science Team (VEST) tool - a revolutionary way to achieve onboard subsystem/instrument autonomy. VEST directly addresses the technology needed for advanced autonomy enablers for spacecraft subsystems. It will significantly support the efficient and cost effective realization of on-board autonomy and contribute directly to realizing the concept of an intelligent autonomous spacecraft. VEST will support the evolution of a subsystem/instrument model that is probably correct and from that model the automatic generation of the code needed to support the autonomous operation of what was modeled. VEST will directly support the integration of the efforts of engineers, scientists, and software technologists. This integration of efforts will be a significant advancement over the way things are currently accomplished. The model, developed through the use of VEST, will be the basis for the physical construction of the subsystem/instrument and the generated code will support its autonomous operation once in space. The close coupling between the model and the code, in the same tool environment, will help ensure that correct and reliable operational control of the subsystem/instrument is achieved.VEST will provide a thoroughly modern interface that will allow users to easily and intuitively input subsystem/instrument requirements and visually get back the system's reaction to the correctness and compatibility of the inputs as the model evolves. User interface/interaction, logic, theorem proving, rule-based and model-based reasoning, and automatic code generation are some of the basic technologies that will be brought into play in realizing VEST.

  13. Interface Supports Lightweight Subsystem Routing for Flight Applications

    NASA Technical Reports Server (NTRS)

    Lux, James P.; Block, Gary L.; Ahmad, Mohammad; Whitaker, William D.; Dillon, James W.

    2010-01-01

    A wireless avionics interface exploits the constrained nature of data networks in flight systems to use a lightweight routing method. This simplified routing means that a processor is not required, and the logic can be implemented as an intellectual property (IP) core in a field-programmable gate array (FPGA). The FPGA can be shared with the flight subsystem application. In addition, the router is aware of redundant subsystems, and can be configured to provide hot standby support as part of the interface. This simplifies implementation of flight applications requiring hot stand - by support. When a valid inbound packet is received from the network, the destination node address is inspected to determine whether the packet is to be processed by this node. Each node has routing tables for the next neighbor node to guide the packet to the destination node. If it is to be processed, the final packet destination is inspected to determine whether the packet is to be forwarded to another node, or routed locally. If the packet is local, it is sent to an Applications Data Interface (ADI), which is attached to a local flight application. Under this scheme, an interface can support many applications in a subsystem supporting a high level of subsystem integration. If the packet is to be forwarded to another node, it is sent to the outbound packet router. The outbound packet router receives packets from an ADI or a packet to be forwarded. It then uses a lookup table to determine the next destination for the packet. Upon detecting a remote subsystem failure, the routing table can be updated to autonomously bypass the failed subsystem.

  14. Embedded Thermal Control for Subsystems for Next Generation Spacecraft Applications

    NASA Technical Reports Server (NTRS)

    Didion, Jeffrey R.

    2015-01-01

    Thermal Fluids and Analysis Workshop, Silver Spring MD NCTS 21070-15. NASA, the Defense Department and commercial interests are actively engaged in developing miniaturized spacecraft systems and scientific instruments to leverage smaller cheaper spacecraft form factors such as CubeSats. This paper outlines research and development efforts among Goddard Space Flight Center personnel and its several partners to develop innovative embedded thermal control subsystems. Embedded thermal control subsystems is a cross cutting enabling technology integrating advanced manufacturing techniques to develop multifunctional intelligent structures to reduce Size, Weight and Power (SWaP) consumption of both the thermal control subsystem and overall spacecraft. Embedded thermal control subsystems permit heat acquisition and rejection at higher temperatures than state of the art systems by employing both advanced heat transfer equipment (integrated heat exchangers) and high heat transfer phenomena. The Goddard Space Flight Center Thermal Engineering Branch has active investigations seeking to characterize advanced thermal control systems for near term spacecraft missions. The embedded thermal control subsystem development effort consists of fundamental research as well as development of breadboard and prototype hardware and spaceflight validation efforts. This paper will outline relevant fundamental investigations of micro-scale heat transfer and electrically driven liquid film boiling. The hardware development efforts focus upon silicon based high heat flux applications (electronic chips, power electronics etc.) and multifunctional structures. Flight validation efforts include variable gravity campaigns and a proposed CubeSat based flight demonstration of a breadboard embedded thermal control system. The CubeSat investigation is technology demonstration will characterize in long-term low earth orbit a breadboard embedded thermal subsystem and its individual components to develop

  15. Statistical error model for a solar electric propulsion thrust subsystem

    NASA Technical Reports Server (NTRS)

    Bantell, M. H.

    1973-01-01

    The solar electric propulsion thrust subsystem statistical error model was developed as a tool for investigating the effects of thrust subsystem parameter uncertainties on navigation accuracy. The model is currently being used to evaluate the impact of electric engine parameter uncertainties on navigation system performance for a baseline mission to Encke's Comet in the 1980s. The data given represent the next generation in statistical error modeling for low-thrust applications. Principal improvements include the representation of thrust uncertainties and random process modeling in terms of random parametric variations in the thrust vector process for a multi-engine configuration.

  16. Solar electric propulsion/instrument/subsystems interaction study

    NASA Technical Reports Server (NTRS)

    Sellen, J. M., Jr.; Cole, R. K.; Kemp, R. F.; Hall, D. F.; Shelton, H.

    1973-01-01

    The interactive effects between a solar electric propulsion system and an electrically propelled scientific spacecraft were examined. The operation of the ion thrusters may impact upon the acquisition and interpretation of data by the science payload of the spacecraft. The effluents from the operation of the electric propulsion unit may also impact upon the operation of the various subsystems of the vehicle. Specific interactive effects were isolated where meaningful levels of interaction may occur. The level of impact upon elements of the science payload and other affected subsystems is examined, and avenues for the reduction or elimination of impact are defined.

  17. Development of a preprototype times wastewater recovery subsystem, addendum

    NASA Technical Reports Server (NTRS)

    Dehner, G. F.

    1984-01-01

    Six tasks are described reflecting subsystem hardware and software modifications and test evaluation of a TIMES wastewater recovery subsystem. The overall results are illustrated in a figure which shows the water production rate, the specific energy corrected to 26.5 VDC, and the product water conductivity at various points in the testing. Four tasks are described reflecting studies performed to develop a preliminary design concept for a next generation TIMES. The overall results of the study are the completion of major design analyses and preliminary configuration layout drawings.

  18. Challenges in the development of the orbiter atmosphere revitalization subsystem

    NASA Technical Reports Server (NTRS)

    Prince, R. N.; Swider, J.; Wojnarowski, J.; Decrisantis, A.; Ord, G. R.; Walleshauser, J. J.; Gibb, J. W.

    1985-01-01

    The space shuttle orbiter atmospheric revitalization subsystem provides thermal and contaminant control as well as total- and oxygen partial-pressure control of the environment within the orbiter crew cabin. Challenges that occurred during the development of this subsystem for the space shuttle orbiter are described. The design of the rotating hardware elements of the system (pumps, fans, etc.) required significant development to meet the requirements of long service life, maintainability, and high cycle-fatigue life. As a result, a stringent development program, particularly in the areas of bearing life and heat dissipation, was required. Another area requiring significant development was cabin humidity control and condensate collection.

  19. Optimizing subsystem test programs. [spacecraft equipment standardization for cost reduction

    NASA Technical Reports Server (NTRS)

    Meyer, W. H.; Pierman, B. C.

    1974-01-01

    The goal of reduction of space system costs is pursued in the areas of standardization of subsystem test requirements as well as overall subsystem test program resource requirements. A number of standard components are being developed by NASA. The rationale for the various environmental tests applicable to future missions and launch vehicles is discussed. The need for and approach to developing standard component specifications is presented. In addition, a method for reduction of test expenditures utilizing indexes of mission effect and hardware history as indicators of test requirements is proposed.

  20. Software Testbed for Developing and Evaluating Integrated Autonomous Subsystems

    NASA Technical Reports Server (NTRS)

    Ong, James; Remolina, Emilio; Prompt, Axel; Robinson, Peter; Sweet, Adam; Nishikawa, David

    2015-01-01

    To implement fault tolerant autonomy in future space systems, it will be necessary to integrate planning, adaptive control, and state estimation subsystems. However, integrating these subsystems is difficult, time-consuming, and error-prone. This paper describes Intelliface/ADAPT, a software testbed that helps researchers develop and test alternative strategies for integrating planning, execution, and diagnosis subsystems more quickly and easily. The testbed's architecture, graphical data displays, and implementations of the integrated subsystems support easy plug and play of alternate components to support research and development in fault-tolerant control of autonomous vehicles and operations support systems. Intelliface/ADAPT controls NASA's Advanced Diagnostics and Prognostics Testbed (ADAPT), which comprises batteries, electrical loads (fans, pumps, and lights), relays, circuit breakers, invertors, and sensors. During plan execution, an experimentor can inject faults into the ADAPT testbed by tripping circuit breakers, changing fan speed settings, and closing valves to restrict fluid flow. The diagnostic subsystem, based on NASA's Hybrid Diagnosis Engine (HyDE), detects and isolates these faults to determine the new state of the plant, ADAPT. Intelliface/ADAPT then updates its model of the ADAPT system's resources and determines whether the current plan can be executed using the reduced resources. If not, the planning subsystem generates a new plan that reschedules tasks, reconfigures ADAPT, and reassigns the use of ADAPT resources as needed to work around the fault. The resource model, planning domain model, and planning goals are expressed using NASA's Action Notation Modeling Language (ANML). Parts of the ANML model are generated automatically, and other parts are constructed by hand using the Planning Model Integrated Development Environment, a visual Eclipse-based IDE that accelerates ANML model development. Because native ANML planners are currently

  1. Design evolution of the orbiter reaction control subsystem

    NASA Technical Reports Server (NTRS)

    Taeber, R. J.; Karakulko, W.; Belvins, D.; Hohmann, C.; Henderson, J.

    1985-01-01

    The challenges of space shuttle orbiter reaction control subsystem development began with selection of the propellant for the subsystem. Various concepts were evaluated before the current Earth storable, bipropellant combination was selected. Once that task was accomplished, additional challenges of designing the system to satisfy the wide range of requirements dictated by operating environments, reusability, and long life were met. Verification of system adequacy was achieved by means of a combination of analysis and test. The studies, the design efforts, and the test and analysis techniques employed in meeting the challenges are described.

  2. Apollo experience report: Crew provisions and equipment subsystem

    NASA Technical Reports Server (NTRS)

    Mcallister, F.

    1972-01-01

    A description of the construction and use of crew provisions and equipment subsystem items for the Apollo Program is presented. The subsystem is composed principally of survival equipment, bioinstrumentation devices, medical components and accessories, water- and waste-management equipment, personal-hygiene articles, docking aids, flight garments (excluding the pressure garment assembly), and various other crew-related accessories. Particular attention is given to items and assemblies that presented design, development, or performance problems: the crew optical alinement sight system, the metering water dispenser, and the waste-management system. Changes made in design and materials to improve the fire safety of the hardware are discussed.

  3. Apollo experience report: Lunar module landing gear subsystem

    NASA Technical Reports Server (NTRS)

    Rogers, W. F.

    1972-01-01

    The development of the lunar module landing gear subsystem through the Apollo 11 lunar landing mission is presented. The landing gear design evolved from the design requirement, which had to satisfy the structural, mechanical, and landing performance constraints of the vehicle. Extensive analyses and tests were undertaken to verify the design adequacy. Techniques of the landing performance analysis served as a primary tool in developing the subsystem hardware and in determining the adequacy of the landing gear for toppling stability and energy absorption. The successful Apollo 11 lunar landing mission provided the first opportunity for a complete flight test of the landing gear under both natural and induced environments.

  4. Definition of an arcjet propulsion sub-system

    NASA Technical Reports Server (NTRS)

    Price, Theodore W.

    1989-01-01

    An engineering flight demonstration of a 100 kW3 Space Reactor Power System is planned for the mid to late 1990s. An arcjet based propulsion subsystem will be included on the flight demonstraction as a secondary experiment. Two studies, sponsored by the Kay Technologies Directorate of the SDI Organization and managed by the Jet Propulsion Laboratory are currently under way to define that propulsion subsystem. The principal tasks of those contracts and the plans for two later phases, an experimental verification of the concept and a flight qualification/delivery of a flight unit, are described.

  5. Seismic Safety Margins Research Program. Phase 1. Project V. Structural sub-system response: subsystem response review. [PWR; BWR

    SciTech Connect

    Fogelquist, J.; Kaul, M.K.; Koppe, R.; Tagart, S.W. Jr.; Thailer, H.; Uffer, R.

    1980-03-01

    This project is directed toward a portion of the Seismic Safety Margins Research Program which includes one link in the seismic methodology chain. The link addressed here is the structural subsystem dynamic response which consists of those components and systems whose behavior is often determined decoupled from the major structural response. Typically the mathematical model utilized for the major structural response will include only the mass effects of the subsystem and the main model is used to produce the support motion inputs for subsystem seismic qualification. The main questions addressed in this report have to do with the seismic response uncertainty of safety-related components or equipment whose seismic qualification is performed by (a) analysis, (b) tests, or (c) combinations of analysis and tests, and where the seismic input is assumed to have no uncertainty.

  6. Reception-Conversion Subsystem (RXCV) for microwave power transmission system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    As part of a program to demonstrate the feasibility of power transmission from space, an approximately 25 sq m Reception-Conversion Subsystem was designed and tested. The device collects high power microwave energy, converts it into dc, and dissipates it in an instrumented demonstration load.

  7. Maximum-rank root subsystems of hyperbolic root systems

    SciTech Connect

    Tumarkin, P V

    2004-02-28

    A Kac-Moody algebra is said to be hyperbolic if it corresponds to a generalized Cartan matrix of hyperbolic type. Root subsystems of root systems of algebras of this kind are studied. The main result of the paper is the classification of the maximum-rank regular hyperbolic subalgebras of hyperbolic Kac-Moody algebras.

  8. Command module/service module reaction control subsystem assessment

    NASA Technical Reports Server (NTRS)

    Weary, D. P.

    1971-01-01

    Detailed review of component failure histories, qualification adequacy, manufacturing flow, checkout requirements and flow, ground support equipment interfaces, subsystem interface verification, protective devices, and component design did not reveal major weaknesses in the command service module (CSM) reaction control system (RCS). No changes to the CSM RCS were recommended. The assessment reaffirmed the adequacy of the CSM RCS for future Apollo missions.

  9. Image Processing In Laser-Beam-Steering Subsystem

    NASA Technical Reports Server (NTRS)

    Lesh, James R.; Ansari, Homayoon; Chen, Chien-Chung; Russell, Donald W.

    1996-01-01

    Conceptual design of image-processing circuitry developed for proposed tracking apparatus described in "Beam-Steering Subsystem For Laser Communication" (NPO-19069). In proposed system, desired frame rate achieved by "windowed" readout scheme in which only pixels containing and surrounding two spots read out and others skipped without being read. Image data processed rapidly and efficiently to achieve high frequency response.

  10. Apollo experience report: Lunar module display and control subsystem

    NASA Technical Reports Server (NTRS)

    Farkas, A. J.

    1972-01-01

    The lunar module display and control subsystem equipment is described with emphasis on major problems and their solutions. Included in the discussion of each item is a description of what the item does and how the item is constructed. The development, hardware history, and testing for each item are also presented.

  11. Emerging Network Storage Management Standards for Intelligent Data Storage Subsystems

    NASA Technical Reports Server (NTRS)

    Podio, Fernando; Vollrath, William; Williams, Joel; Kobler, Ben; Crouse, Don

    1998-01-01

    This paper discusses the need for intelligent storage devices and subsystems that can provide data integrity metadata, the content of the existing data integrity standard for optical disks and techniques and metadata to verify stored data on optical tapes developed by the Association for Information and Image Management (AIIM) Optical Tape Committee.

  12. Cascade Distillation Subsystem Development: Progress Toward a Distillation Comparison Test

    NASA Technical Reports Server (NTRS)

    Callahan, M. R.; Lubman, A.; Pickering, Karen D.

    2009-01-01

    Recovery of potable water from wastewater is essential for the success of long-duration manned missions to the Moon and Mars. Honeywell International and a team from NASA Johnson Space Center (JSC) are developing a wastewater processing subsystem that is based on centrifugal vacuum distillation. The wastewater processor, referred to as the Cascade Distillation Subsystem (CDS), utilizes an innovative and efficient multistage thermodynamic process to produce purified water. The rotary centrifugal design of the system also provides gas/liquid phase separation and liquid transport under microgravity conditions. A five-stage subsystem unit has been designed, built, delivered and integrated into the NASA JSC Advanced Water Recovery Systems Development Facility for performance testing. A major test objective of the project is to demonstrate the advancement of the CDS technology from the breadboard level to a subsystem level unit. An initial round of CDS performance testing was completed in fiscal year (FY) 2008. Based on FY08 testing, the system is now in development to support an Exploration Life Support (ELS) Project distillation comparison test expected to begin in early 2009. As part of the project objectives planned for FY09, the system will be reconfigured to support the ELS comparison test. The CDS will then be challenged with a series of human-gene-rated waste streams representative of those anticipated for a lunar outpost. This paper provides a description of the CDS technology, a status of the current project activities, and data on the system s performance to date.

  13. Mark 4A DSN receiver-exciter and transmitter subsystems

    NASA Technical Reports Server (NTRS)

    Wick, M. R.

    1986-01-01

    The present configuration of the Mark 4A DSN Receiver-Exciter and Transmitter Subsystems is described. Functional requirements and key characteristics are given to show the differences in the capabilities required by the Networks Consolidation task for combined High Earth Orbiter and Deep Space Network tracking support.

  14. Solid rocket booster thrust vector control subsystem description

    NASA Technical Reports Server (NTRS)

    Redmon, J., Jr. (Compiler)

    1983-01-01

    Major Solid Rocket Booster-Thrust Vector Control (SRB-TVC) subsystem components and subcomponents used in the Space Transportation System (STS) are identified. Simplified schematics, detailed schematics, figures, photographs, and data are included to acquaint the reader with the operation, performance, and physical layout as well as the materials and instrumentation used.

  15. Aircraft subsystems inspection: objective and easy... then, why skimp?

    NASA Astrophysics Data System (ADS)

    Mehrotra, Yogesh

    2000-03-01

    Both NUVU and NUVU-IR instruments are now a proven demonstrated technology based on sound scientific concepts. They are designed to eliminate any crystal-ball approach to life prediction of aircraft wiring and cable subsystems. It is scientific, not magic.

  16. ANALYTICAL TOOL DEVELOPMENT FOR AFTERTREATMENT SUB-SYSTEMS INTEGRATION

    SciTech Connect

    Bolton, B; Fan, A; Goney, K; Pavlova-MacKinnon, Z; Sisken, K; Zhang, H

    2003-08-24

    The stringent emissions standards of 2007 and beyond require complex engine, aftertreatment and vehicle systems with a high degree of sub-system interaction and flexible control solutions. This necessitates a system-based approach to technology development, in addition to individual sub-system optimization. Analytical tools can provide an effective means to evaluate and develop such complex technology interactions as well as understand phenomena that is either too expensive or impossible to study with conventional experimental means. The analytical effort can also guide experimental development and thus lead to efficient utilization of available experimental resources.A suite of analytical models has been developed to represent PM and NOx aftertreatment sub-systems. These models range from computationally inexpensive zero-dimensional models for real-time control applications to CFD-based, multi-dimensional models with detailed temporal and spatial resolution. Such models in conjunction with well established engine modeling tools such as engine cycle simulation, engine controls modeling, CFD models of non-combusting and combusting flow, and vehicle models provide a comprehensive analytical toolbox for complete engine, aftertreatment and vehicle sub-systems development and system integration applications. However, the fidelity of aftertreatment models and application going forward is limited by the lack of fundamental kinetic data.

  17. Double Shell Tank (DST) Diluent and Flush Subsystem Specification

    SciTech Connect

    GRAVES, C.E.

    2000-04-27

    The Double-Shell Tank (DST) Diluent and Flush Subsystem is intended to support Waste Feed Delivery. The DST Diluent and Flush Subsystem specification describes the relationship of this system with the DST System, describes the functions that must be performed by the system, and establishes the performance requirements to be applied to the design of the system. It also provides references for the requisite codes and standards. The DST Diluent and Flush Subsystem will treat the waste for a more favorable waste transfer. This will be accomplished by diluting the waste, dissolving the soluble portion of the waste, and flushing waste residuals from the transfer line. The Diluent and Flush Subsystem will consist of the following: The Diluent and Flush Station(s) where chemicals will be off-loaded, temporarily stored, mixed as necessary, heated, and metered to the delivery system; and A piping delivery system to deliver the chemicals to the appropriate valve or pump pit Associated support structures. This specification is intended to be the basis for new projects/installations. This specification is not intended to retroactively affect previously established project design criteria without specific direction by the program.

  18. Long Duration Space Missions: Human Subsystem Risks and Requirements

    NASA Technical Reports Server (NTRS)

    Kundrot, Criag E.

    2011-01-01

    This viewgraph presentation reviews the human health and performance risks associated with long duration space flight beyond low earth orbit. The contents include: 1) Human Research Program; 2) Human Subsystem Risks; 3) Human Exploration Framework Team (HEFT) Architecture Elements; 4) Potentially Unacceptable Risks -1; 5) Potentially Unacceptable Risks-2; and 6) Major Mission Drivers of Risk.

  19. The OCLC Serials Sub-System: A First Evaluation.

    ERIC Educational Resources Information Center

    Edgar, Neal L.; And Others

    This examination of the OCLC serials control sub-system points to positive and negative aspects of the OCLC system as they relate to serials, and evaluates the system's serials cataloging capabilities. While this report assumes a knowledge of the basic operations of OCLC, it describes the system in general, its function in cataloging, and its…

  20. Subsystems in Nearby Solar-type Wide Binaries

    NASA Astrophysics Data System (ADS)

    Tokovinin, Andrei; Hartung, Markus; Hayward, Thomas L.

    2010-08-01

    We conducted a deep survey of resolved subsystems among wide binaries with solar-type components within 67 pc of the Sun. Images of 61 stars in the K and H bands were obtained with the Near-Infrared Coronagraphic Imager adaptive-optics instrument on the 8 m Gemini-South telescope. Our maximum detectable magnitude difference is about 5 mag and 7.8 mag at 0farcs15 and 0farcs9 separations, respectively. This enables a complete census of subsystems with stellar companions in the projected separation range from 5 to 100 AU. Out of seven such companions found in our sample, only one was previously known. We determine that the fraction of subsystems with projected separations above 5 AU is 0.12 ± 0.04 and that the distribution of their mass ratio is flat, with a power-law index of 0.2 ± 0.5. Comparing this with the properties of closer spectroscopic subsystems (separations below 1 AU), it appears that the mass-ratio distribution does not depend on the separation. The frequency of subsystems in the separation ranges below 1 AU and between 5 and 100 AU is similar, about 0.15. Unbiased statistics of multiplicity higher than 2, advanced by this work, provide constraints on star formation theory. Based on observations obtained at the Gemini Observatory (Program ID GS-2009B-Q-49), which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  1. Energy Efficient Engine Low Pressure Subsystem Flow Analysis

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Lynn, Sean R.; Heidegger, Nathan J.; Delaney, Robert A.

    1998-01-01

    The objective of this project is to provide the capability to analyze the aerodynamic performance of the complete low pressure subsystem (LPS) of the Energy Efficient Engine (EEE). The analyses were performed using three-dimensional Navier-Stokes numerical models employing advanced clustered processor computing platforms. The analysis evaluates the impact of steady aerodynamic interaction effects between the components of the LPS at design and off-design operating conditions. Mechanical coupling is provided by adjusting the rotational speed of common shaft-mounted components until a power balance is achieved. The Navier-Stokes modeling of the complete low pressure subsystem provides critical knowledge of component aero/mechanical interactions that previously were unknown to the designer until after hardware testing.

  2. Energy Efficient Engine Low Pressure Subsystem Aerodynamic Analysis

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Delaney, Robert A.; Lynn, Sean R.; Veres, Joseph P.

    1998-01-01

    The objective of this study was to demonstrate the capability to analyze the aerodynamic performance of the complete low pressure subsystem (LPS) of the Energy Efficient Engine (EEE). Detailed analyses were performed using three- dimensional Navier-Stokes numerical models employing advanced clustered processor computing platforms. The analysis evaluates the impact of steady aerodynamic interaction effects between the components of the LPS at design and off- design operating conditions. Mechanical coupling is provided by adjusting the rotational speed of common shaft-mounted components until a power balance is achieved. The Navier-Stokes modeling of the complete low pressure subsystem provides critical knowledge of component acro/mechanical interactions that previously were unknown to the designer until after hardware testing.

  3. ERSYS-SPP access method subsystem design specification

    NASA Technical Reports Server (NTRS)

    Weise, R. C. (Principal Investigator)

    1980-01-01

    The STARAN special purpose processor (SPP) is a machine allowing the same operation to be performed on up to 512 different data elements simultaneously. In the ERSYS system, it is to be attached to a 4341 plug compatible machine (PCM) to do certain existing algorithms and, at a later date, to perform other to be specified algorithms. That part of the interface between the 4341 PCM and the SPP located in the 4341 PCM is known as the SPP access method (SPPAM). Access to the SPPAM will be obtained by use of the NQUEUE and DQUEUE commands. The subsystem design specification is to incorporate all applicable design considerations from the ERSYS system design specification and the Level B requirements documents relating to the SPPAM. It is intended as a basis for the preliminary design review and will expand into the subsystem detailed design specification.

  4. Subsystem software for TSTA (Tritium Systems Test Assembly)

    SciTech Connect

    Mann, L.W.; Claborn, G.W.; Nielson, C.W.

    1987-01-01

    The Subsystem Control Software at the Tritium System Test Assembly (TSTA) must control sophisticated chemical processes through the physical operation of valves, motor controllers, gas sampling devices, thermocouples, pressure transducers, and similar devices. Such control software has to be capable of passing stringent quality assurance (QA) criteria to provide for the safe handling of significant amounts of tritium on a routine basis. Since many of the chemical processes and physical components are experimental, the control software has to be flexible enough to allow for trial/error learning curve, but still protect the environment and personnel from exposure to unsafe levels of radiation. The software at TSTA is implemented in several levels as described in a preceding paper in these proceedings. This paper depends on information given in the preceding paper for understanding. The top level is the Subsystem Control level.

  5. The skeletal subsystem as an integrative physiology paradigm.

    PubMed

    Weiss, Aaron J; Iqbal, Jameel; Zaidi, Neeha; Mechanick, Jeffrey I

    2010-12-01

    Homeostatic bone remodeling depends on precise regulation of osteoblast-osteoclast coupling through intricate endocrine, immune, neuronal, and mechanical factors. The osteoblast-osteoclast model of bone physiology with layers of regulatory complexity can be investigated as a component of a local skeletal subsystem or as a part of a complete whole-body system. In this review, we flip the traditional investigative paradigm of scientific experimentation ("bottom-top research") to a "top-bottom" approach using systems biology. We first establish the intricacies of the two-cell model at the molecular signaling level. We then provide, on a systems level, an integrative physiologic approach involving many recognized organ-level subsystems having direct and/or indirect effects on bone remodeling. Lastly, a hypothetical model of bone remodeling based on frequency and amplitude regulatory mechanisms is presented. It is hoped that by providing a thorough model of skeletal homeostasis, future progress can be made in researching and treating skeletal morbidities.

  6. Development of a preprototype sabatier CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Birbara, P.

    1980-01-01

    A preoprototype Sabatier CO2 Reduction Subsystem was successfully designed, fabricated and tested. The lightweight, quick starting reactor utilizes a highly active and physically durable methanation catalyst composed of ruthenium on alumina. The use of this improved catalyst permits a single straight through plug flow design with an average lean component H2/CO2 conversion efficiency of over 99% over a range of H2/CO2 molar ratios of 1.8 to 5 while operating with flows equivalent to a crew size of one person steadystate to 3 persons cyclical (equivalent to 5 persons steady state). The reactor requires no heater operation after start-up even during simulated 55 minute lightside/39 minute darkside orbital operation over the above range of molar ratios and crew loadings. The subsystem's operation and performance is controlled by a microprocessor and displayed on a nineteen inch multi-colored cathode ray tube.

  7. Development of a preprototype Sabatier CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Birbara, P.

    1981-01-01

    A lightweight, quick starting reactor utilizes a highly active and physically durable methanation catalyst composed of ruthenium on alumina. The use of this improved catalyst permits a single straight through plug flow design with an average lean component H2/CO2 conversion efficiency of over 99% over a range of H2/CO2 molar ratios of 1.8 to 5 while operating with flows equivalent to a crew size of one person steadystate to 3 persons cyclical. The reactor requires no heater operation after start-up even during simulated 55 minute lightside/39 minute darkside orbital operation over the above range of molar ratios and crew loadings. Subsystem performance was proven by parametric testing and endurance testing over a wide range of crew sizes and metabolic loadings. The subsystem's operation and performance is controlled by a microprocessor and displayed on a nineteen inch multi-colored cathode ray tube.

  8. Development of an advanced Sabatier CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Cusick, R. J.

    1981-01-01

    A preprototype Sabatier CO2 reduction subsystem was successfully designed, fabricated and tested. The lightweight, quick starting (less than 5 minutes) reactor utlizes a highly active and physically durable methanation catalyst composed of ruthenium on alumina. The use of this improved catalyst permits a simple, passively controlled reactor design with an average lean component H2/CO2 conversion efficiency of over 99% over a range of H2/CO2 molar ratios of 1.8 to 5 while operating with process flows equivalent to a crew size of up to five persons. The subsystem requires no heater operation after start-up even during simulated 55 minute lightside/39 minute darkside orbital operation.

  9. [The innovative dynamic of the mechanics, electronics and materials subsystem].

    PubMed

    Maldonado, José; Gadelha, Carlos Augusto Grabois; Costa, Laís Silveira; Vargas, Marco

    2012-12-01

    The mechanics, electronics and materials subsystem, one of the subsystems of the health care productive complex, encompasses different activities, usually clustered in what is called the medical, hospital and dental equipment and materials industry. This is a strategic area for health care, since it represents a continuous source of changes in care practices, and influences the provision of health care services. It has, moreover, potential for promoting the progress of Brazil's system of innovation and for increasing the competitiveness of the industry as a whole, given that it articulates future technologies. Despite the significant growth of this industry in Brazil in recent years, such equipment and materials have been presenting a growing deficit in the balance of trade. This incompatibility between national health care needs and the productive and innovative basis of the industry points to structural fragilities in the system. Using the framework of political economy, the article aims to discuss the development of this industry in Brazil and its challenges.

  10. Entanglement, subsystem particle numbers and topology in free fermion systems.

    PubMed

    Zhang, Y F; Sheng, L; Shen, R; Wang, Rui; Xing, D Y

    2014-03-12

    We study the relationship between bipartite entanglement, subsystem particle number and topology in a half-filled free fermion system. It is proposed that the spin-projected particle numbers can distinguish the quantum spin Hall state from other states, and can be used to establish a new topological index for the system. Furthermore, we apply the new topological invariant to a disordered system and show that a topological phase transition occurs when the disorder strength is increased beyond a critical value. It is also shown that the subsystem particle number fluctuation displays behavior very similar to that of the entanglement entropy. This provides a lower-bound estimation for the entanglement entropy, which can be utilized to obtain an estimate of the entanglement entropy experimentally.

  11. Pyrotechnic Actuator for Retracting Tubes Between MSL Subsystems

    NASA Technical Reports Server (NTRS)

    Gallon, John C.; Webster, Richard G.; Patterson, Keith D.; Orzewalla, Matthew A.; Roberts, Eric T.; Tuszynski, Andrew J.

    2010-01-01

    An apparatus, denoted the "retractuator" (a contraction of "retracting actuator"), was designed to help ensure clean separation between the cruise stage and the entry-vehicle subsystem of the Mars Science Laboratory (MSL) mission. The retractuator or an equivalent mechanism is needed because of tubes that (1) transport a heat-transfer fluid between the stages during flight and (2) are cut immediately prior to separation of the stages retractuator. The role of the retractuator is to retract the tubes, after they are cut and before separation of the subsystem, so that cut ends of the tubes do not damage thermal-protection coats on the entry vehicle and do not contribute to uncertainty of drag and consequent uncertainty in separation velocity.

  12. Automated monitor and control for deep space network subsystems

    NASA Technical Reports Server (NTRS)

    Smyth, P.

    1989-01-01

    The problem of automating monitor and control loops for Deep Space Network (DSN) subsystems is considered and an overview of currently available automation techniques is given. The use of standard numerical models, knowledge-based systems, and neural networks is considered. It is argued that none of these techniques alone possess sufficient generality to deal with the demands imposed by the DSN environment. However, it is shown that schemes that integrate the better aspects of each approach and are referenced to a formal system model show considerable promise, although such an integrated technology is not yet available for implementation. Frequent reference is made to the receiver subsystem since this work was largely motivated by experience in developing an automated monitor and control loop for the advanced receiver.

  13. OAO-3 end of mission power subsystem evaluation

    NASA Technical Reports Server (NTRS)

    Tasevoli, M.

    1982-01-01

    End of mission tests were performed on the OAO-3 power subsystem in three component areas: solar array, nickel-cadmium batteries and the On-Board Processor (OBP) power boost operation. Solar array evaluation consisted of analyzing array performance characteristics and comparing them to earlier flight data. Measured solar array degradation of 14.1 to 17.7% after 8 1/3 years is in good agreement with theortical radiation damage losses. Battery discharge characteristics were compared to results of laboratory life cycle tests performed on similar cells. Comparison of cell voltage profils reveals close correlation and confirms the validity of real time life cycle simulation. The successful operation of the system in the OBP/power boost regulation mode demonstrates the excellent life, reliability and greater system utilization of power subsystems using maximum power trackers.

  14. System integration of marketable subsystems. [for residential solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Progress is reported in the following areas: systems integration of marketable subsystems; development, design, and building of site data acquisition subsystems; development and operation of the central data processing system; operation of the MSFC Solar Test Facility; and systems analysis.

  15. Thermal performance evaluation of the infrared telescope dewar subsystem

    NASA Technical Reports Server (NTRS)

    Urban, E. W.

    1986-01-01

    Thermal performance evaluations (TPE) were conducted with the superfluid helium dewar of the Infrared Telescope (IRT) experiment from November 1981 to August 1982. Test included measuring key operating parameters, simulating operations with an attached instrument cryostat and validating servicing, operating and safety procedures. Test activities and results are summarized. All objectives are satisfied except for those involving transfer of low pressure liquid helium (LHe) from a supply dewar into the dewar subsystem.

  16. GENERAL: Nonadiabatic Geometric Phase in Composite Systems and Its Subsystem

    NASA Astrophysics Data System (ADS)

    Li, Xin

    2008-11-01

    We point out that the time-dependent gauge transformation technique may be effective in investigating the nonadiabatic geometric phase of a subsystem in a composite system. As an example, we consider two uniaxially coupled spin —1/2 particles with one of particles driven by rotating magnetic Geld. The influences of coupling and precession frequency of the magnetic Geld on geometric phase are also discussed in detail.

  17. Simultaneous Time, Wavelength and Intensity Measurement of Optical Memory Subsystems

    DTIC Science & Technology

    1998-07-01

    SIMULTANEOUS TIME, WAVELENGTH AND INTENSITY MEASUREMENT PE - 61102F OF OPTICAL MEMORY SUBSYSTEMS PR - 2300 6. AUTHOR( S ) TA - 06 WU -03 Joseph Osman and...Rebecca Bussjager 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER AFRL/SNDP25 letnic AFRL-SN-RS-TR- 1998...12025 Electronic Pky Rome, NY 13441-4515 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY REPORT NUMBER

  18. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

    1996-01-01

    This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

  19. Photovoltaic subsystem optimization and design tradeoff study. Final report

    SciTech Connect

    Stolte, W.J.

    1982-03-01

    Tradeoffs and subsystem choices are examined in photovoltaic array subfield design, power-conditioning sizing and selection, roof- and ground-mounted structure installation, energy loss, operating voltage, power conditioning cost, and subfield size. Line- and self-commutated power conditioning options are analyzed to determine the most cost-effective technology in the megawatt power range. Methods for reducing field installation of flat panels and roof mounting of intermediate load centers are discussed, including the cost of retrofit installations.

  20. Evolution of the 1-mlb mercury ion thruster subsystem

    NASA Technical Reports Server (NTRS)

    Kerslake, W. R.; Banks, B. A.

    1978-01-01

    The developmental history, performance, and major lifetests of each component of the present 1-mlb (4.5 mN) thruster system are traced over the past 10 years. The 1-mlb thruster subsystem consists of an 8 cm diameter ion thruster mounted on 2 axis gimbals, a mercury propellant tank, a power electronics unit, a controller/digital interface unit, and necessary electrical harnesses plus propellant tankage and feed lines.

  1. Design and Analysis of a Hyperspectral Microwave Receiver Subsystem

    NASA Technical Reports Server (NTRS)

    Blackwell, W.; Galbraith, C.; Hancock, T.; Leslie, R.; Osaretin, I.; Shields, M.; Racette, P.; Hillard, L.

    2012-01-01

    Hyperspectral microwave (HM) sounding has been proposed to achieve unprecedented performance. HM operation is achieved using multiple banks of RF spectrometers with large aggregate bandwidth. A principal challenge is Size/Weight/Power scaling. Objectives of this work: 1) Demonstrate ultra-compact (100 cm3) 52-channel IF processor (enabler); 2) Demonstrate a hyperspectral microwave receiver subsystem; and 3) Deliver a flight-ready system to validate HM sounding.

  2. TRIGA: Telecommunications Protocol Processing Subsystem Using Reconfigurable Interoperable Gate Arrays

    NASA Technical Reports Server (NTRS)

    Pang, Jackson; Pingree, Paula J.; Torgerson, J. Leigh

    2006-01-01

    We present the Telecommunications protocol processing subsystem using Reconfigurable Interoperable Gate Arrays (TRIGA), a novel approach that unifies fault tolerance, error correction coding and interplanetary communication protocol off-loading to implement CCSDS File Delivery Protocol and Datalink layers. The new reconfigurable architecture offers more than one order of magnitude throughput increase while reducing footprint requirements in memory, command and data handling processor utilization, communication system interconnects and power consumption.

  3. Earth-to-orbit propulsion turbomachinery subsystem: Overview

    NASA Technical Reports Server (NTRS)

    Schutzenhofer, L. A.; Garcia, R.

    1991-01-01

    The topics presented are covered in viewgraph form. The objectives are: (1) to develop the technology related to the turbomachinery systems of high performance rocket engines, which focuses on advanced design methodologies and concepts, develops high performance turbomachinery data bases, and validates turbomachinery design tools; and (2) specific turbomachinery subsystems and disciplines, which focus on turbine stages, pump stages, bearings, deals, structural dynamics, complex flow paths, materials, manufacturability, producibility, and inspectability, rotordynamics, and fatigue/fracture/life.

  4. Systems Approach to Terrorism: Countering the Terrorist Training Subsystem

    DTIC Science & Technology

    2006-12-01

    TERRORISM : COUNTERING THE TERRORIST TRAINING SUBSYSTEM by Erdogan Celebi December 2006 Thesis Advisor: Nancy Roberts Second Reader...REPORT DATE December 2006 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Systems Approach to Terrorism : Countering the...distribution is unlimited 12b. DISTRIBUTION CODE A 13. ABSTRACT This study on terrorism training follows the logic that terrorism is a

  5. Radioisotope thermoelectric generator transportation system subsystem 143 software development plan

    SciTech Connect

    King, D.A.

    1994-11-10

    This plan describes the activities to be performed and the controls to be applied to the process of specifying, developing, and qualifying the data acquisition software for the Radioisotope Thermoelectric Generator (RTG) Transportation System Subsystem 143 Instrumentation and Data Acquisition System (IDAS). This plan will serve as a software quality assurance plan, a verification and validation (V and V) plan, and a configuration management plan.

  6. Radioisotope thermoelectric generator transportation system subsystem 143 software development plan

    NASA Astrophysics Data System (ADS)

    King, D. A.

    1994-11-01

    This plan describes the activities to be performed and the controls to be applied to the process of specifying, developing, and qualifying the data acquisition software for the Radioisotope Thermoelectric Generator (RTG) Transportation System Subsystem 143 Instrumentation and Data Acquisition System (IDAS). This plan will serve as a software quality assurance plan, a verification and validation (V and V) plan, and a configuration management plan.

  7. Design of nanophotonic circuits for autonomous subsystem quantum error correction

    NASA Astrophysics Data System (ADS)

    Kerckhoff, J.; Pavlichin, D. S.; Chalabi, H.; Mabuchi, H.

    2011-05-01

    We reapply our approach to designing nanophotonic quantum memories in order to formulate an optical network that autonomously protects a single logical qubit against arbitrary single-qubit errors. Emulating the nine-qubit Bacon-Shor subsystem code, the network replaces the traditionally discrete syndrome measurement and correction steps by continuous, time-independent optical interactions and coherent feedback of unitarily processed optical fields.

  8. Development of Testing Station for Prototype Rover Thermal Subsystem

    NASA Technical Reports Server (NTRS)

    Burlingame, Kaitlin

    2010-01-01

    In order to successfully and efficiently explore the moon or other planets, a vehicle must be built to assist astronauts as they travel across the surface. One concept created to meet this need is NASA's Space Exploration Vehicle (SEV). The SEV, a small pressurized cabin integrated onto a 12-wheeled chassis, can support two astronauts up to 14 days. Engineers are currently developing the second generation of the SEV, with the goal of being faster, more robust, and able to carry a heavier payload. In order to function properly, the rover must dissipate heat produced during operation and maintain an appropriate temperature profile inside the rover. If these activities do not occur, components of the rover will start to break down, eventually leading to the failure of the rover. On the rover, these requirements are the responsibility of the thermal subsystem. My project for the summer was to design and build a testing station to facilitate the design and testing of the new thermal subsystem. As the rover develops, initial low fidelity parts can be interchanged for the high fidelity parts used on the rover. Based on a schematic of the proposed thermal system, I sized and selected parts for each of the components in the thermal subsystem. For the components in the system that produced heat but had not yet been finalized or fabricated, I used power resistors to model their load patterns. I also selected all of the fittings to put the system together and a mounting platform to support the testing station. Finally, I implemented sensors at various points in the system to measure the temperature, pressure, and flow rate, and a data acquisition system to collect this information. In the future, the information from these sensors will be used to study the behavior of the subsystem under different conditions and select the best part for the rover.

  9. Static Feed Water Electrolysis Subsystem Testing and Component Development

    NASA Technical Reports Server (NTRS)

    Koszenski, E. P.; Schubert, F. H.; Burke, K. A.

    1983-01-01

    A program was carried out to develop and test advanced electrochemical cells/modules and critical electromechanical components for a static feed (alkaline electrolyte) water electrolysis oxygen generation subsystem. The accomplishments were refurbishment of a previously developed subsystem and successful demonstration for a total of 2980 hours of normal operation; achievement of sustained one-person level oxygen generation performance with state-of-the-art cell voltages averaging 1.61 V at 191 ASF for an operating temperature of 128F (equivalent to 1.51V when normalized to 180F); endurance testing and demonstration of reliable performance of the three-fluid pressure controller for 8650 hours; design and development of a fluid control assembly for this subsystem and demonstration of its performance; development and demonstration at the single cell and module levels of a unitized core composite cell that provides expanded differential pressure tolerance capability; fabrication and evaluation of a feed water electrolyte elimination five-cell module; and successful demonstration of an electrolysis module pressurization technique that can be used in place of nitrogen gas during the standby mode of operation to maintain system pressure and differential pressures.

  10. Laser and Optical Subsystem for NASA's Cold Atom Laboratory

    NASA Astrophysics Data System (ADS)

    Kohel, James; Kellogg, James; Elliott, Ethan; Krutzik, Markus; Aveline, David; Thompson, Robert

    2016-05-01

    We describe the design and validation of the laser and optics subsystem for NASA's Cold Atom Laboratory (CAL), a multi-user facility being developed at NASA's Jet Propulsion Laboratory for studies of ultra-cold quantum gases in the microgravity environment of the International Space Station. Ultra-cold atoms will be generated in CAL by employing a combination of laser cooling techniques and evaporative cooling in a microchip-based magnetic trap. Laser cooling and absorption imaging detection of bosonic mixtures of 87 Rb and 39 K or 41 K will be accomplished using a high-power (up to 500 mW ex-fiber), frequency-agile dual wavelength (767 nm and 780 nm) laser and optical subsystem. The CAL laser and optical subsystem also includes the capability to generate high-power multi-frequency optical pulses at 784.87 nm to realize a dual-species Bragg atom interferometer. Currently at Humboldt-Universität zu Berlin.

  11. Double Shell Tank (DST) Transfer Pump Subsystem Specification

    SciTech Connect

    LESHIKAR, G.A.

    2000-03-27

    This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied to the Double-Shell Tank (DST) Transfer Pump Subsystem which supports the first phase of Waste Feed Delivery (WFD). This specification establishes the performance requirements and provides the references to the requisite codes and standards to be applied during the design of the DST Transfer Pump Subsystem that supports the first phase of (WFD). The DST Transfer Pump Subsystem consists of a pump for supernatant and or slurry transfer for the DSTs that will be retrieved during the Phase 1 WFD operations. This system is used to transfer low-activity waste (LAW) and high-level waste (HLW) to designated DST staging tanks. It also will deliver blended LAW and HLW feed from these staging tanks to the River Protection Project (RPP) Privatization Contractor facility where it will be processed into an immobilized waste form. This specification is intended to be the basis for new projects/installations (W-521, etc.). This specification is not intended to retroactively affect previously established project design criteria without specific direction by the program.

  12. Space Shuttle Orbiter audio subsystem. [to communication and tracking system

    NASA Technical Reports Server (NTRS)

    Stewart, C. H.

    1978-01-01

    The selection of the audio multiplex control configuration for the Space Shuttle Orbiter audio subsystem is discussed and special attention is given to the evaluation criteria of cost, weight and complexity. The specifications and design of the subsystem are described and detail is given to configurations of the audio terminal and audio central control unit (ATU, ACCU). The audio input from the ACCU, at a signal level of -12.2 to 14.8 dBV, nominal range, at 1 kHz, was found to have balanced source impedance and a balanced local impedance of 6000 + or - 600 ohms at 1 kHz, dc isolated. The Lyndon B. Johnson Space Center (JSC) electroacoustic test laboratory, an audio engineering facility consisting of a collection of acoustic test chambers, analyzed problems of speaker and headset performance, multiplexed control data coupled with audio channels, and the Orbiter cabin acoustic effects on the operational performance of voice communications. This system allows technical management and project engineering to address key constraining issues, such as identifying design deficiencies of the headset interface unit and the assessment of the Orbiter cabin performance of voice communications, which affect the subsystem development.

  13. Predicting Speech Intelligibility with a Multiple Speech Subsystems Approach in Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Lee, Jimin; Hustad, Katherine C.; Weismer, Gary

    2014-01-01

    Purpose: Speech acoustic characteristics of children with cerebral palsy (CP) were examined with a multiple speech subsystems approach; speech intelligibility was evaluated using a prediction model in which acoustic measures were selected to represent three speech subsystems. Method: Nine acoustic variables reflecting different subsystems, and…

  14. On DESTINY Science Instrument Electrical and Electronics Subsystem Framework

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Benford, Dominic J.; Lauer, Tod R.

    2009-01-01

    Future space missions are going to require large focal planes with many sensing arrays and hundreds of millions of pixels all read out at high data rates'' . This will place unique demands on the electrical and electronics (EE) subsystem design and it will be critically important to have high technology readiness level (TRL) EE concepts ready to support such missions. One such omission is the Joint Dark Energy Mission (JDEM) charged with making precise measurements of the expansion rate of the universe to reveal vital clues about the nature of dark energy - a hypothetical form of energy that permeates all of space and tends to increase the rate of the expansion. One of three JDEM concept studies - the Dark Energy Space Telescope (DESTINY) was conducted in 2008 at the NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. This paper presents the EE subsystem framework, which evolved from the DESTINY science instrument study. It describes the main challenges and implementation concepts related to the design of an EE subsystem featuring multiple focal planes populated with dozens of large arrays and millions of pixels. The focal planes are passively cooled to cryogenic temperatures (below 140 K). The sensor mosaic is controlled by a large number of Readout Integrated Circuits and Application Specific Integrated Circuits - the ROICs/ASICs in near proximity to their sensor focal planes. The ASICs, in turn, are serviced by a set of "warm" EE subsystem boxes performing Field Programmable Gate Array (FPGA) based digital signal processing (DSP) computations of complex algorithms, such as sampling-up-the-ramp algorithm (SUTR), over large volumes of fast data streams. The SUTR boxes are supported by the Instrument Control/Command and Data Handling box (ICDH Primary and Backup boxes) for lossless data compression, command and low volume telemetry handling, power conversion and for communications with the spacecraft. The paper outlines how the JDEM DESTINY concept

  15. Test Methods for Telemetry Systems and Subsystems. Volume 2: Test Methods for Telemetry Radio Frequency (RF) Subsystems

    DTIC Science & Technology

    2012-09-01

    than 50°). Set the output of the signal generator to the minimum level and the attenuator to maximum attenuation. Verify that no extraneous radio ... Extraterrestrial Radio Sources in the Measurement of Antenna Parameters, Institute of Electrical and Electronics Engineers Transactions on Aerospace and...RCC DOCUMENT 118-12 VOLUME 2 TELEMETRY GROUP TEST METHODS FOR TELEMETRY SYSTEMS AND SUBSYSTEMS VOLUME 2 TEST METHODS FOR TELEMETRY RADIO

  16. Autonomous navigation - The ARMMS concept. [Autonomous Redundancy and Maintenance Management Subsystem

    NASA Technical Reports Server (NTRS)

    Wood, L. J.; Jones, J. B.; Mease, K. D.; Kwok, J. H.; Goltz, G. L.; Kechichian, J. A.

    1984-01-01

    A conceptual design is outlined for the navigation subsystem of the Autonomous Redundancy and Maintenance Management Subsystem (ARMMS). The principal function of this navigation subsystem is to maintain the spacecraft over a specified equatorial longitude to within + or - 3 deg. In addition, the navigation subsystem must detect and correct internal faults. It comprises elements for a navigation executive and for orbit determination, trajectory, maneuver planning, and maneuver command. Each of these elements is described. The navigation subsystem is to be used in the DSCS III spacecraft.

  17. National Ignition Facility, subsystem design requirements beam control {ampersand} laser diagnostics SSDR 1.7

    SciTech Connect

    Bliss, E.

    1996-11-01

    This Subsystem Design Requirement document is a development specification that establishes the performance, design, development, and test requirements for the Alignment subsystem (WBS 1.7.1), Beam Diagnostics (WBS 1.7.2), and the Wavefront Control subsystem (WBS 1.7. 3) of the NIF Laser System (WBS 1.3). These three subsystems are collectively referred to as the Beam Control & Laser Diagnostics Subsystem. The NIF is a multi-pass, 192-beam, high-power, neodymium-glass laser that meets requirements set forth in the NIF SDR 002 (Laser System). 3 figs., 3 tabs.

  18. Systems and methods for an integrated electrical sub-system powered by wind energy

    DOEpatents

    Liu, Yan; Garces, Luis Jose

    2008-06-24

    Various embodiments relate to systems and methods related to an integrated electrically-powered sub-system and wind power system including a wind power source, an electrically-powered sub-system coupled to and at least partially powered by the wind power source, the electrically-powered sub-system being coupled to the wind power source through power converters, and a supervisory controller coupled to the wind power source and the electrically-powered sub-system to monitor and manage the integrated electrically-powered sub-system and wind power system.

  19. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

  20. A cost effective data management subsystem for the LST

    NASA Technical Reports Server (NTRS)

    Dougherty, J. A.; Patterson, T. D.; Cole, A. E.

    1975-01-01

    The paper outlines the approach used in developing DMS (Data Management Subsystem) alternatives for the LST (Large Space Telescope) and in selecting the concept considered to be the most cost effective means of implementing the LST DMS requirements. Two candidate DMS concepts are discussed: a functionally integrated and a functionally separated one. For the single vehicle LST program, separation of the DMS functions best provides high reliability, operations flexibility, minimal interface complexity, and the least complex software development and verification task. The use of available hardware and NASA standard components is stressed.

  1. Malaria as anthropo-ecosystem. Part VI: Demographic subsystem (DSS).

    PubMed

    Kondrashin, A V; Kalra, N I

    1991-06-01

    Demographic Subsystem (DSS) comprising structure, distribution, along with its dynamic process has been identified to influence Malaria as Anthropo-Ecosystem (MAES) broadly in two ways. Innate characters of some essential elements of DSS viz. growth, age and sex composition, infants, children, young and old adults, non-pregnant and pregnant and lactating mothers exert direct influence while other elements, viz. spatial distribution, density, configuration of settlements and migration are influenced by environmental factors and affect MAES indirectly. Attempt has been made to discuss each of these factors in the light of present knowledge and available data.

  2. Automation study for space station subsystems and mission ground support

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An automation concept for the autonomous operation of space station subsystems, i.e., electric power, thermal control, and communications and tracking are discussed. To assure that functions essential for autonomous operations are not neglected, an operations function (systems monitoring and control) is included in the discussion. It is recommended that automated speech recognition and synthesis be considered a basic mode of man/machine interaction for space station command and control, and that the data management system (DMS) and other systems on the space station be designed to accommodate fully automated fault detection, isolation, and recovery within the system monitoring function of the DMS.

  3. Use of STS subsystems and components for MMSE, volume 1

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Multiuse mission support equipment (MMSE) is flight/ground equipment for the shuttle era which is used in conjunction with more than one mission payload. Initial verification of STS subsystem's applicability to MMSE is provided along with the cost savings potential and programmatic data needed for further program planning decisions. Some 70 MMSE requirements were found to be potentially satisfied by STS equipment, and and 6 items of particular interest were chosen for special emphasis. All were found to be feasible and beneficial. Program cost savings through their use are estimated to be substantial. Further study is recommended to identify additional MMSE requirements and hardware.

  4. Addendum: Development of a preprototype times wastewater recovery subsystem

    NASA Technical Reports Server (NTRS)

    Dehner, G. F.

    1984-01-01

    The results of the second generation operational improvements and the TIMES (Thermoelectric Integrated Membrane Evaporation Subsystem) 2 study are covered. Areas covered in the second generation operational improvements are improved temperature control, water quality improvements, subsytem operational improvements, solid handling improvements, wastewater pretreatment optimization, and membrane rejuvenation concepts. The task for the TIMES 2 study are thermoelectric regenerator improvement, recycle loop pH operational criteria, recycle loop component optimization, and hollow fiber membrane evaporator improvement. Results are presented and conclusions are drawn from both studies.

  5. A shuttle radar microwave subsystem for earth resources applications

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Microwave subsystem considerations are discussed as a design example for a radar for earth resources applications to be used in conjunction with the shuttle spacelab. This system with a multiplicity of frequencies and polarizations - L-band (25-cm wavelength), S-band (10-cm wavelength), and X-band (3.2-cm wavelength) at two orthogonal linear polarizations - was tentatively selected. The space shuttle vehicle constrains the antenna to approximately 8 m in length and 3 m in width. The frequencies and antenna size comprise the major constraints on the system described, and determine the sensor altitude, coverage, and major hardware parameters.

  6. Recent developments for the Large Binocular Telescope Guiding Control Subsystem

    NASA Astrophysics Data System (ADS)

    Golota, T.; De La Peña, M. D.; Biddick, C.; Lesser, M.; Leibold, T.; Miller, D.; Meeks, R.; Hahn, T.; Storm, J.; Sargent, T.; Summers, D.; Hill, J.; Kraus, J.; Hooper, S.; Fisher, D.

    2014-07-01

    The Large Binocular Telescope (LBT) has eight Acquisition, Guiding, and wavefront Sensing Units (AGw units). They provide guiding and wavefront sensing capability at eight different locations at both direct and bent Gregorian focal stations. Recent additions of focal stations for PEPSI and MODS instruments doubled the number of focal stations in use including respective motion, camera controller server computers, and software infrastructure communicating with Guiding Control Subsystem (GCS). This paper describes the improvements made to the LBT GCS and explains how these changes have led to better maintainability and contributed to increased reliability. This paper also discusses the current GCS status and reviews potential upgrades to further improve its performance.

  7. Attitude determination and control subsystem for the TOPEX satellite

    NASA Technical Reports Server (NTRS)

    Dennehy, C. J.; Welch, R. V.; Kia, T.

    1988-01-01

    The Ocean Topography Experiment satellite will carry a modular Attitude Determination and Control Subsystem (ADCS) which contains all equipment required for attitude determination, stabilization, and control, as well as hydrazine thruster firing control, during all mission phases. Attention is presently given to the ADCS's architecture, constituent hardware components, performance requirements, and predicted on-orbit performance compliance, with emphasis on the design and analysis of the Normal Mission Mode control algorithm furnishing the primary scientific data-acquisition operational mode. This mode's attitude determination and control of on-orbit performance is predicted to better than 43 arcsec.

  8. Subsystem fault tolerance with the Bacon-Shor code.

    PubMed

    Aliferis, Panos; Cross, Andrew W

    2007-06-01

    We discuss how the presence of gauge subsystems in the Bacon-Shor code [D. Bacon, Phys. Rev. A 73, 012340 (2006)10.1103/PhysRevA.73.012340 (2006)] leads to remarkably simple and efficient methods for fault-tolerant error correction (FTEC). Most notably, FTEC does not require entangled ancillary states, and it can be implemented with nearest-neighbor two-qubit measurements. By using these methods, we prove a lower bound on the quantum accuracy threshold, 1.94 x 10(-4) for adversarial stochastic noise, that improves previous lower bounds by nearly an order of magnitude.

  9. Space Shuttle Orbiter - Reusable surface insulation subsystem thermal performance

    NASA Technical Reports Server (NTRS)

    Dotts, R. L.; Battley, H. H.; Hughes, J. T.; Neuenschwander, W. E.

    1982-01-01

    The thermal performance of the reusable surface insulation (RSI) subsystem consisting of silica tiles, silicone coated nylon felt insulation, and ceramic cloth gap fillers and thermal barriers is discussed. Thermal response predictions for the components are compared with measured flight data, which indicates that the RSI thermal performance can meet or exceed design requirements for the majority of the RSI. Visual inspections and the maximum temperature conditions observed in structural components after data acquisition suggest that the flight environment was not as severe as the worst case preflight prediction.

  10. Electric and hybrid vehicles environmental control subsystem study

    NASA Technical Reports Server (NTRS)

    1981-01-01

    An environmental control subsystem (ECS) in the passenger compartment of electric and hybrid vehicles is studied. Various methods of obtaining the desired temperature control for the battery pack is also studied. The functional requirements of ECS equipment is defined. Following categorization by methodology, technology availability and risk, all viable ECS concepts are evaluated. Each is assessed independently for benefits versus risk, as well as for its feasibility to short, intermediate and long term product development. Selection of the preferred concept is made against these requirements, as well as the study's major goal of providing safe, highly efficient and thermally confortable ECS equipment.

  11. Electric and hybrid vehicle environmental control subsystem study

    NASA Technical Reports Server (NTRS)

    Heitner, K. L.

    1980-01-01

    An environmental control subsystem (ECS) in electric and hybrid vehicles is studied. A combination of a combustion heater and gasoline engine (Otto cycle) driven vapor compression air conditioner is selected. The combustion heater, the small gasoline engine, and the vapor compression air conditioner are commercially available. These technologies have good cost and performance characteristics. The cost for this ECS is relatively close to the cost of current ECS's. Its effect on the vehicle's propulsion battery is minimal and the ECS size and weight do not have significant impact on the vehicle's range.

  12. Data Management Applications for the Service Preparation Subsystem

    NASA Technical Reports Server (NTRS)

    Luong, Ivy P.; Chang, George W.; Bui, Tung; Allen, Christopher; Malhotra, Shantanu; Chen, Fannie C.; Bui, Bach X.; Gutheinz, Sandy C.; Kim, Rachel Y.; Zendejas, Silvino C.; Yu, Dan; Kim, Richard M.; Sadaqathulla, Syed

    2009-01-01

    These software applications provide intuitive User Interfaces (UIs) with a consistent look and feel for interaction with, and control of, the Service Preparation Subsystem (SPS). The elements of the UIs described here are the File Manager, Mission Manager, and Log Monitor applications. All UIs provide access to add/delete/update data entities in a complex database schema without requiring technical expertise on the part of the end users. These applications allow for safe, validated, catalogued input of data. Also, the software has been designed in multiple, coherent layers to promote ease of code maintenance and reuse in addition to reducing testing and accelerating maturity.

  13. The sensing and perception subsystem of the NASA research telerobot

    NASA Technical Reports Server (NTRS)

    Wilcox, B.; Gennery, D. B.; Bon, B.; Litwin, T.

    1987-01-01

    A useful space telerobot for on-orbit assembly, maintenance, and repair tasks must have a sensing and perception subsystem which can provide the locations, orientations, and velocities of all relevant objects in the work environment. This function must be accomplished with sufficient speed and accuracy to permit effective grappling and manipulation. Appropriate symbolic names must be attached to each object for use by higher-level planning algorithms. Sensor data and inferences must be presented to the remote human operator in a way that is both comprehensible in ensuring safe autonomous operation and useful for direct teleoperation. Research at JPL toward these objectives is described.

  14. Characterization of Subsystems for a WB-003 Single Stage Shuttle

    NASA Technical Reports Server (NTRS)

    MacConochie, Ian O.; Lepsch, Roger A., Jr. (Technical Monitor)

    2002-01-01

    Subsystems for an all oxygen-hydrogen-single-stage shuttle are characterized for a vehicle designated WB-003. Features of the vehicle include all-electric actuation, fiber optics for information circuitry, fuel cells for power generation, and extensive use of composites for structure. The vehicle is sized for the delivery of a 25,000 lb. payload to a space station orbit without crew. When crew are being delivered, they are carried in a module in the payload bay with escape and manual override capabilities. The underlying reason for undertaking this task is to provide a framework for the study of the operations costs of the newer shuttles.

  15. Revalidation of the Huygens Descent Control Sub-System

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The Huygens probe, part of the Cassini mission to Saturn, is designed to investigate the atmosphere of Titan, Saturn's largest moon. The passage of the probe through the atmosphere is controlled by the Descent Control Sub-System (DCSS), which consists of three parachutes and associated mechanisms. The Cassini / Huygens mission was launched in October 1997 and was designed during the early 1990's. During the time since the design and launch, analysis capabilities have improved significantly, knowledge of the Titan environment has improved and the baseline mission has been modified. Consequently, a study was performed to revalidate the DCSS design against the current predictions.

  16. Reactor Subsystem Simulation for Nuclear Hybrid Energy Systems

    SciTech Connect

    Shannon Bragg-Sitton; J. Michael Doster; Alan Rominger

    2012-09-01

    Preliminary system models have been developed by Idaho National Laboratory researchers and are currently being enhanced to assess integrated system performance given multiple sources (e.g., nuclear + wind) and multiple applications (i.e., electricity + process heat). Initial efforts to integrate a Fortran-based simulation of a small modular reactor (SMR) with the balance of plant model have been completed in FY12. This initial effort takes advantage of an existing SMR model developed at North Carolina State University to provide initial integrated system simulation for a relatively low cost. The SMR subsystem simulation details are discussed in this report.

  17. Orbits of Subsystems in Four Hierarchical Multiple Stars

    NASA Astrophysics Data System (ADS)

    Tokovinin, Andrei

    2016-07-01

    Seven spectroscopic orbits in nearby solar-type multiple stars are presented. The primary of the chromospherically active star HIP 9642 is a 4.8 day double-lined pair; the outer 420 year visual orbit is updated, but remains poorly constrained. HIP 12780 is a quadruple system consisting of the resolved 6.7 year pair FIN 379 Aa,Ab, for which the combined orbit, masses, and orbital parallax are determined here, and the single-lined binary Ba,Bb with a period of 27.8 days. HIP 28790 is a young quintuple system composed of two close binaries, Aa,Ab and Ba,Bb, with periods of 221 and 13 days, respectively, and a single distant component C. Its subsystem Ba,Bb is peculiar, having a spectroscopic mass ratio of 0.89 but a magnitude difference of ˜2.2 mag. HIP 64478 also contains five stars: the A-component is a 29 year visual pair with a previously known 4 day twin subsystem, while the B-component is a contact binary with a period of 5.8 hr, seen nearly pole-on.

  18. Optimisation study of a vehicle bumper subsystem with fuzzy parameters

    NASA Astrophysics Data System (ADS)

    Farkas, L.; Moens, D.; Donders, S.; Vandepitte, D.

    2012-10-01

    This paper deals with the design and optimisation for crashworthiness of a vehicle bumper subsystem, which is a key scenario for vehicle component design. The automotive manufacturers and suppliers have to find optimal design solutions for such subsystems that comply with the conflicting requirements of the regulatory bodies regarding functional performance (safety and repairability) and regarding the environmental impact (mass). For the bumper design challenge, an integrated methodology for multi-attribute design engineering of mechanical structures is set up. The integrated process captures the various tasks that are usually performed manually, this way facilitating the automated design iterations for optimisation. Subsequently, an optimisation process is applied that takes the effect of parametric uncertainties into account, such that the system level of failure possibility is acceptable. This optimisation process is referred to as possibility-based design optimisation and integrates the fuzzy FE analysis applied for the uncertainty treatment in crash simulations. This process is the counterpart of the reliability-based design optimisation used in a probabilistic context with statistically defined parameters (variabilities).

  19. Near-infrared mapping spectrometer optical subsystem development and testing

    NASA Technical Reports Server (NTRS)

    Macenka, S. A.

    1983-01-01

    The Near-Infrared Mapping Spectrometer (NIMS) is one of the four remote-sensing science instruments of the Galileo Orbiter scientific payload. The NIMS scientific objectives require operating the detector and optical subsystem at cryogenic temperatures. The necessity of assembling, aligning, and testing the optics at room temperature and meeting design specifications at the cryogenic operating temperature (130 K) presented a set of challenging technical problems. A systematic approach to the development of athermalized mounts and supporting structures for optical components is described. A technique utilizing the visible spectral range and supplementary ray-trace information for alignment of an infrared instrument is presented. The optical subsystem point-spread function and spatial and spectral resolution were determined at room temperature using selected spectral and spatial targets. Based on thermal-distortion analyses of the structure and mounts, compensators were selected, implemented, and verified at cryogenic temperatures. The selection of the compensator and the overall system performance were verified in a thermal vacuum chamber. Various external and internal calibration targets were used.

  20. Independent Orbiter Assessment (IOA): Analysis of the instrumentation subsystem

    NASA Technical Reports Server (NTRS)

    Howard, B. S.

    1986-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Instrumentation Subsystem are documented. The Instrumentation Subsystem (SS) consists of transducers, signal conditioning equipment, pulse code modulation (PCM) encoding equipment, tape recorders, frequency division multiplexers, and timing equipment. For this analysis, the SS is broken into two major groupings: Operational Instrumentation (OI) equipment and Modular Auxiliary Data System (MADS) equipment. The OI equipment is required to acquire, condition, scale, digitize, interleave/multiplex, format, and distribute operational Orbiter and payload data and voice for display, recording, telemetry, and checkout. It also must provide accurate timing for time critical functions for crew and payload specialist use. The MADS provides additional instrumentation to measure and record selected pressure, temperature, strain, vibration, and event data for post-flight playback and analysis. MADS data is used to assess vehicle responses to the flight environment and to permit correlation of such data from flight to flight. The IOA analysis utilized available SS hardware drawings and schematics for identifying hardware assemblies and components and their interfaces. Criticality for each item was assigned on the basis of the worst-case effect of the failure modes identified.

  1. Rotating field collector subsystem phase 1 study and evaluation

    NASA Astrophysics Data System (ADS)

    Jones, D.; Eibling, J. A.

    1982-10-01

    The rotating field collector system is an alternative concept in which all heliostats are mounted on a single large platform which rotates around a tower to track the azumuthal angle of the Sun. Each heliostat is mounted to the platform with appropriate pivots, linkage, and controls to provide the additional positioning required to properly direct the solar radiation onto the receiver. The results are presented of the first phase of a study to investigate the technical and economic merits of a particular type of rotating field collector subsystem. The large pie-shaped platform would revolve over an array of support pedestals by means of a roller at the top of each pedestal. Several heliostats were built to demonstrate their construction features, and the operation of both flat and amphitheater rotating fields was studied. Work included an analysis of the concepts, development of modifications and additions to make the system comply with design criteria, and cost estimates to be used for comparison with other heliostat subsystems. Because of considerably high cost estimates, the focus of a large part of the study was directed toward developing lower cost designs of major components.

  2. ARES I Upper Stage Subsystems Design and Development

    NASA Technical Reports Server (NTRS)

    Frate, David T.; Senick, Paul F.; Tolbert, Carol M.

    2011-01-01

    From 2005 through early 2011, NASA conducted concept definition, design, and development of the Ares I launch vehicle. The Ares I was conceived to serve as a crew launch vehicle for beyond-low-Earth-orbit human space exploration missions as part of the Constellation Program Architecture. The vehicle was configured with a single shuttle-derived solid rocket booster first stage and a new liquid oxygen/liquid hydrogen upper stage, propelled by a single, newly developed J-2X engine. The Orion Crew Exploration Vehicle was to be mated to the forward end of the Ares I upper stage through an interface with fairings and a payload adapter. The vehicle design passed a Preliminary Design Review in August 2008, and was nearing the Critical Design Review when efforts were concluded as a result of the Constellation Program s cancellation. At NASA Glenn Research Center, four subsystems were developed for the Ares I upper stage. These were thrust vector control (TVC) for the J-2X, electrical power system (EPS), purge and hazardous gas (P&HG), and development flight instrumentation (DFI). The teams working each of these subsystems achieved 80 percent or greater design completion and extensive development testing. These efforts were extremely successful representing state-of-the-art technology and hardware advances necessary to achieve Ares I reliability, safety, availability, and performance requirements. This paper documents the designs, development test activity, and results.

  3. Satellite Power System (SPS) microwave subsystem impacts and benefits

    NASA Technical Reports Server (NTRS)

    Dickinson, R. M.

    1977-01-01

    The impacts and benefits to society of the microwave subsystem resulting from the developing, construction and operating of a space solar power to earth, electric power delivery system are presented and discussed. The primary benefit (usable energy) is conveyed mainly in the fundamental frequency portion of the RF radiation beam that is intercepted and converted to electric power output. The small fraction of the microwave and other electromagnetic energy that does not end up in the electric utility grid, yields most of the subsystem impacts. The impacts range from harmonics and noise radiated by the transmitting antenna, through potential interference with ionospheric communications and navigation caused by the power beam heating the ionosphere, to the potential large land area requirements for the rectennas and low level microwave radiation around the rectennas. Additional benefits range from a very low level of waste heat liberated and lack of atmospheric emissions including noise while operating to having no residual ionizing radiation from the rectenna when it is deactivated.

  4. On the subsystem formulation of linear-response time-dependent DFT.

    PubMed

    Pavanello, Michele

    2013-05-28

    A new and thorough derivation of linear-response subsystem time-dependent density functional theory (TD-DFT) is presented and analyzed in detail. Two equivalent derivations are presented and naturally yield self-consistent subsystem TD-DFT equations. One reduces to the subsystem TD-DFT formalism of Neugebauer [J. Chem. Phys. 126, 134116 (2007)]. The other yields Dyson type equations involving three types of subsystem response functions: coupled, uncoupled, and Kohn-Sham. The Dyson type equations for subsystem TD-DFT are derived here for the first time. The response function formalism reveals previously hidden qualities and complications of subsystem TD-DFT compared with the regular TD-DFT of the supersystem. For example, analysis of the pole structure of the subsystem response functions shows that each function contains information about the electronic spectrum of the entire supersystem. In addition, comparison of the subsystem and supersystem response functions shows that, while the correlated response is subsystem additive, the Kohn-Sham response is not. Comparison with the non-subjective partition DFT theory shows that this non-additivity is largely an artifact introduced by the subjective nature of the density partitioning in subsystem DFT.

  5. The development of the intrinsic functional connectivity of default network subsystems from age 3 to 5.

    PubMed

    Xiao, Yaqiong; Zhai, Hongchang; Friederici, Angela D; Jia, Fucang

    2016-03-01

    In recent years, research on human functional brain imaging using resting-state fMRI techniques has been increasingly prevalent. The term "default mode" was proposed to describe a baseline or default state of the brain during rest. Recent studies suggested that the default mode network (DMN) is comprised of two functionally distinct subsystems: a dorsal-medial prefrontal cortex (DMPFC) subsystem involved in self-oriented cognition (i.e., theory of mind) and a medial temporal lobe (MTL) subsystem engaged in memory and scene construction; both subsystems interact with the anterior medial prefrontal cortex (aMPFC) and posterior cingulate (PCC) as the core regions of DMN. The present study explored the development of DMN core regions and these two subsystems in both hemispheres from 3- to 5-year-old children. The analysis of the intrinsic activity showed strong developmental changes in both subsystems, and significant changes were specifically found in MTL subsystem, but not in DMPFC subsystem, implying distinct developmental trajectories for DMN subsystems. We found stronger interactions between the DMPFC and MTL subsystems in 5-year-olds, particularly in the left subsystems that support the development of environmental adaptation and relatively complex mental activities. These results also indicate that there is stronger right hemispheric lateralization at age 3, which then changes as bilateral development gradually increases through to age 5, suggesting in turn the hemispheric dominance in DMN subsystems changing with age. The present results provide primary evidence for the development of DMN subsystems in early life, which might be closely related to the development of social cognition in childhood.

  6. Subsystem Quantum Mechanics and its Applications to Crystalline Systems

    NASA Astrophysics Data System (ADS)

    Zou, Pengfei

    This thesis reports results of the author's investigations along the theme that both dynamic and static properties of molecules and solids can be expressed in terms of their parts from theoretical and applied aspects. Specifically, the following four main results are obtained: (1) A topological analysis of the charge density in crystals has been developed. This is an extension of the theory of molecular structure to crystalline systems. Relationships between the bulk properties of a crystal and its topological structure have been established. A comparison of the topological properties of molecules and crystals have been made. (2) The theory of atoms in molecules has been extended to a crystal and yields a variational definition of a Wigner-Seitz cell. This definition maximizes the relation of the cell to the physical form exhibited by the charge density and the derived structure factors that account, in a natural way, for the observed intensities of scattered electrons and X-rays. It has been demonstrated that the theory of atoms in molecules and crystals can provide a way to model the behaviour of solids. This is done through the use of the fact that atomic properties are often transferable from one system to another. (3) The subsystem variational principle has been reformulated in terms of quantum field theoretical language and the subsystem Feynman path integrals of electrons have been obtained using the coherent representation. This part contributes to the foundation of the theory of atoms in molecules and crystals. (4) Both dynamic and static quantum mechanical subspace techniques have been extensively investigated. A new variational method has been derived for embedding one system in another using the R-matrix formalism within the density functional approach. A formal subspace perturbation scheme has been proposed. These methods aim to obtain the charge distribution of a subsystem starting from known reference systems. Before I came here I was confused about

  7. Understanding the requirements imposed by programming model middleware on a common communication subsystem.

    SciTech Connect

    Buntinas, D.; Gropp, W.

    2005-12-13

    In high-performance parallel computing, most programming-model middleware libraries and runtime systems use a communication subsystem to abstract the lower-level network layer. The functionality required of a communication subsystem depends largely on the programming model implemented by the middleware. In order to maximize performance, middleware libraries and runtime systems typically implement their own communication subsystems that are specially tuned for the middleware, rather than use an existing communication subsystem. This situation leads to duplicated effort and prevents different middleware libraries from being used by the same application in hybrid programming models. In this paper we describe features required by various middleware libraries as well as some desirable features that would make it easier to port a middleware library to the communication subsystem and allow the middleware to make use of high-performance features provided by some networking layers. We show that none of the communication subsystems that we evaluate support all of the features.

  8. A development and integration analysis of commercial and in-house control subsystems

    SciTech Connect

    Moore, D.M.; Dalesio, L.R.

    1998-12-31

    The acquisition and integration of commercial automation and control subsystems in physics research is becoming more common. It is presumed these systems present lower risk and less cost. This paper studies four subsystems used in the Accelerator Production of Tritium (APT) Low Energy Demonstration Accelerator (LEDA) at the Los Alamos National Laboratory (LANL). The radio frequency quadrupole (RFQ) resonance-control cooling subsystem (RCCS), the high-power RF subsystem and the RFQ vacuum subsystem were outsourced; the low-level RF (LLRF) subsystem was developed in-house. Based on the authors experience a careful evaluation of the costs and risks in acquisition, implementation, integration, and maintenance associated with these approaches is given.

  9. SNAP-27/ALSEP power subsystem used in the Apollo program.

    NASA Technical Reports Server (NTRS)

    Remini, W. C.; Grayson, J. H.

    1972-01-01

    The Apollo Lunar Surface Experiments Package (ALSEP) measures lunar physical and environmental characteristics and transmits the data to receiving stations on earth. The data are used to derive information on the composition and structure of the moon. The electrical power subsystem generates and conditions all the electrical power for operations of the ALSEP system. The power source for the ALSEP is the Systems for Nuclear Auxiliary Power (SNAP) Radioisotope Thermoelectric Generator (RTG). The generator produces electricity by thermoelectric conversion. The radioactive isotope plutonium 238 is used as the energy source for the SNAP-27. By April 1, 1970, the SNAP-27 RTG had produced more than 230 kWh of continuous and stable power for the ALSEP.-

  10. Propellant Feed Subsystem for the X-34 Main Propulsion System

    NASA Technical Reports Server (NTRS)

    McDonald, J. P.; Minor, R. B.; Knight, K. C.; Champion, R. H., Jr.; Russell, F. J., Jr.

    1998-01-01

    The Orbital Sciences Corporation X-34 vehicle demonstrates technologies and operations key to future reusable launch vehicles. The general flight performance goal of this unmanned rocket plane is Mach 8 flight at an altitude of 250,000 feet. The Main Propulsion System supplies liquid propellants to the main engine, which provides the primary thrust for attaining mission goals. Major NMS design and operational goals are aircraft-like ground operations, quick turnaround between missions, and low initial/operational costs. This paper reviews major design and analysis aspects of the X-34 propellant feed subsystem of the X-34 Main Propulsion System. Topics include system requirements, system design, the integration of flight and feed system performance, propellant acquisition at engine start, and propellant tank terminal drain.

  11. Lacie phase 1 Classification and Mensuration Subsystem (CAMS) rework experiment

    NASA Technical Reports Server (NTRS)

    Chhikara, R. S.; Hsu, E. M.; Liszcz, C. J.

    1976-01-01

    An experiment was designed to test the ability of the Classification and Mensuration Subsystem rework operations to improve wheat proportion estimates for segments that had been processed previously. Sites selected for the experiment included three in Kansas and three in Texas, with the remaining five distributed in Montana and North and South Dakota. The acquisition dates were selected to be representative of imagery available in actual operations. No more than one acquisition per biophase were used, and biophases were determined by actual crop calendars. All sites were worked by each of four Analyst-Interpreter/Data Processing Analyst Teams who reviewed the initial processing of each segment and accepted or reworked it for an estimate of the proportion of small grains in the segment. Classification results, acquisitions and classification errors and performance results between CAMS regular and ITS rework are tabulated.

  12. An advanced carbon reactor subsystem for carbon dioxide reduction

    NASA Technical Reports Server (NTRS)

    Noyes, Gary P.; Cusick, Robert J.

    1986-01-01

    An evaluation is presented of the development status of an advanced carbon-reactor subsystem (ACRS) for the production of water and dense, solid carbon from CO2 and hydrogen, as required in physiochemical air revitalization systems for long-duration manned space missions. The ACRS consists of a Sabatier Methanation Reactor (SMR) that reduces CO2 with hydrogen to form methane and water, a gas-liquid separator to remove product water from the methane, and a Carbon Formation Reactor (CFR) to pyrolize methane to carbon and hydrogen; the carbon is recycled to the SMR, while the produce carbon is periodically removed from the CFR. A preprototype ACRS under development for the NASA Space Station is described.

  13. The Earth Observing System AM Spacecraft - Thermal Control Subsystem

    NASA Technical Reports Server (NTRS)

    Chalmers, D.; Fredley, J.; Scott, C.

    1993-01-01

    Mission requirements for the EOS-AM Spacecraft intended to monitor global changes of the entire earth system are considered. The spacecraft is based on an instrument set containing the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER), Clouds and Earth's Radiant Energy System (CERES), Multiangle Imaging Spectro-Radiometer (MISR), Moderate-Resolution Imaging Spectrometer (MODIS), and Measurements of Pollution in the Troposphere (MOPITT). Emphasis is placed on the design, analysis, development, and verification plans for the unique EOS-AM Thermal Control Subsystem (TCS) aimed at providing the required environments for all the onboard equipment in a densely packed layout. The TCS design maximizes the use of proven thermal design techniques and materials, in conjunction with a capillary pumped two-phase heat transport system for instrument thermal control.

  14. Progress report for the scintillator plate calorimeter subsystem

    SciTech Connect

    Not Available

    1990-12-31

    This report covers the work completed in FY90 by ANL staff and those of Westinghouse STC and BICRON Corporation under subcontract to ANL towards the design of a compensating calorimeter based on the use of scintillator plate as the sensitive medium. It is presented as five task sections dealing with respectively mechanical design; simulation studies; optical system design; electronics development; development of rad hard plastic scintillator and wavelength shifter and a summary. The work carried out by the University of Tennessee under a subcontract from ANL is reported separately. Finally, as principal institution with responsibility for the overall management of this subsystem effort, the summary here reports the conclusions resulting from the work of the collaboration and their impact on our proposed direction of effort in FY91. This proposal, for obvious reasons is given separately.

  15. Performance characterization of a Bosch CO sub 2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

    1980-01-01

    The performance of Bosch hardware at the subsystem level (up to five-person capacity) in terms of five operating parameters was investigated. The five parameters were: (1) reactor temperature, (2) recycle loop mass flow rate, (3) recycle loop gas composition (percent hydrogen), (4) recycle loop dew point and (5) catalyst density. Experiments were designed and conducted in which the five operating parameters were varied and Bosch performance recorded. A total of 12 carbon collection cartridges provided over approximately 250 hours of operating time. Generally, one cartridge was used for each parameter that was varied. The Bosch hardware was found to perform reliably and reproducibly. No startup, reaction initiation or carbon containment problems were observed. Optimum performance points/ranges were identified for the five parameters investigated. The performance curves agreed with theoretical projections.

  16. SSC detector muon sub-system beam tests

    SciTech Connect

    Downing, R.; Errede, S.; Gauthier, A.; Haney, M.; Karliner, I.; Liss, T.; O`Halloran, T.; Sheldon, P.; Simiatis, V.; Thaler, J.; Wiss, J.; Green, D.; Martin, P.; Morfin, J.; Kunori, S.; Skuja, A.; Okusawa, T.; Takahashi, T.; Teramoto, Y.; Yoshida, T.; Asano, Y.; Mann, T.; Davisson, R.; Liang, G.; Lubatti, H.; Wilkes, R.; Zhao, T.; Carlsmith, D.

    1993-08-01

    We propose to start a test-beam experiment at Fermilab studying the problems associated with tracking extremely high energy muons through absorbers. We anticipate that in this energy range the observation of the muons will be complicated by associated electromagnetic radiation Monte Carlo simulations of this background need to be tuned by direct observations. These beam tests are essential to determine important design parameters of a SSC muon detector, such as the choice of the tracking, geometry, hardware triggering schemes, the number of measuring stations, the amount of iron between measuring stations, etc. We intend to begin the first phase of this program in November of 1990 utilizing the Tevatron muon beam. We plan to measure the multiplicity, direction, and separation of secondary particles associated with the primary muon track as it emerges from an absorber. The second phase of beam test in 1992 or later will be a full scale test for the final design chosen in our muon subsystem proposal.

  17. Designing RF control subsystems using the VXIbus standard

    SciTech Connect

    Stepp, J.D.; Vong, F.C.; Bridges, J.F.

    1993-08-01

    Various components are being designed to control the RF system of the 7-GeV Advanced Photon Source (APS). The associated control electronics (phase shifters, amplitude modulators, phase detectors, automatic tuning control, and local feedback control) are designed as modular cards with multiple channels for ease of replacement as well as for compact design. Various specifications of the VXIbus are listed and the method used to simplify the design of the control subsystem is shown. A commercial VXI interface board was used to speed the design cycle. Required manpower and actual task times are included. A discussion of the computer architecture and software development of the device drivers which allowed computer control from a VME processor located in a remote crate operating under the Experimental Physics and Industrial Controls Software (EPICS) program is also presented.

  18. Portable Life Support Subsystem Thermal Hydraulic Performance Analysis

    NASA Technical Reports Server (NTRS)

    Barnes, Bruce; Pinckney, John; Conger, Bruce

    2010-01-01

    This paper presents the current state of the thermal hydraulic modeling efforts being conducted for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS). The goal of these efforts is to provide realistic simulations of the PLSS under various modes of operation. The PLSS thermal hydraulic model simulates the thermal, pressure, flow characteristics, and human thermal comfort related to the PLSS performance. This paper presents modeling approaches and assumptions as well as component model descriptions. Results from the models are presented that show PLSS operations at steady-state and transient conditions. Finally, conclusions and recommendations are offered that summarize results, identify PLSS design weaknesses uncovered during review of the analysis results, and propose areas for improvement to increase model fidelity and accuracy.

  19. Principal Components Analysis of a JWST NIRSpec Detector Subsystem

    NASA Technical Reports Server (NTRS)

    Arendt, Richard G.; Fixsen, D. J.; Greenhouse, Matthew A.; Lander, Matthew; Lindler, Don; Loose, Markus; Moseley, S. H.; Mott, D. Brent; Rauscher, Bernard J.; Wen, Yiting; Wilson, Donna V.; Xenophontos, Christos

    2013-01-01

    We present principal component analysis (PCA) of a flight-representative James Webb Space Telescope NearInfrared Spectrograph (NIRSpec) Detector Subsystem. Although our results are specific to NIRSpec and its T - 40 K SIDECAR ASICs and 5 m cutoff H2RG detector arrays, the underlying technical approach is more general. We describe how we measured the systems response to small environmental perturbations by modulating a set of bias voltages and temperature. We used this information to compute the systems principal noise components. Together with information from the astronomical scene, we show how the zeroth principal component can be used to calibrate out the effects of small thermal and electrical instabilities to produce cosmetically cleaner images with significantly less correlated noise. Alternatively, if one were designing a new instrument, one could use a similar PCA approach to inform a set of environmental requirements (temperature stability, electrical stability, etc.) that enabled the planned instrument to meet performance requirements

  20. Subsystem-based theoretical spectroscopy of biomolecules and biomolecular assemblies.

    PubMed

    Neugebauer, Johannes

    2009-12-21

    The absorption properties of chromophores in biomolecular systems are subject to several fine-tuning mechanisms. Specific interactions with the surrounding protein environment often lead to significant changes in the excitation energies, but bulk dielectric effects can also play an important role. Moreover, strong excitonic interactions can occur in systems with several chromophores at close distances. For interpretation purposes, it is often desirable to distinguish different types of environmental effects, such as geometrical, electrostatic, polarization, and response (or differential polarization) effects. Methods that can be applied for theoretical analyses of such effects are reviewed herein, ranging from continuum and point-charge models to explicit quantum chemical subsystem methods for environmental effects. Connections to physical model theories are also outlined. Prototypical applications to optical spectra and excited states of fluorescent proteins, biomolecular photoreceptors, and photosynthetic protein complexes are discussed.