Science.gov

Sample records for high performance control

  1. High performance magnetically controllable microturbines.

    PubMed

    Tian, Ye; Zhang, Yong-Lai; Ku, Jin-Feng; He, Yan; Xu, Bin-Bin; Chen, Qi-Dai; Xia, Hong; Sun, Hong-Bo

    2010-11-01

    Reported in this paper is two-photon photopolymerization (TPP) fabrication of magnetic microturbines with high surface smoothness towards microfluids mixing. As the key component of the magnetic photoresist, Fe(3)O(4) nanoparticles were carefully screened for homogeneous doping. In this work, oleic acid stabilized Fe(3)O(4) nanoparticles synthesized via high-temperature induced organic phase decomposition of an iron precursor show evident advantages in particle morphology. After modification with propoxylated trimethylolpropane triacrylate (PO(3)-TMPTA, a kind of cross-linker), the magnetic nanoparticles were homogeneously doped in acrylate-based photoresist for TPP fabrication of microstructures. Finally, a magnetic microturbine was successfully fabricated as an active mixing device for remote control of microfluids blending. The development of high quality magnetic photoresists would lead to high performance magnetically controllable microdevices for lab-on-a-chip (LOC) applications. PMID:20721411

  2. High performance composites with active stiffness control.

    PubMed

    Tridech, Charnwit; Maples, Henry A; Robinson, Paul; Bismarck, Alexander

    2013-09-25

    High performance carbon fiber reinforced composites with controllable stiffness could revolutionize the use of composite materials in structural applications. Here we describe a structural material, which has a stiffness that can be actively controlled on demand. Such a material could have applications in morphing wings or deployable structures. A carbon fiber reinforced-epoxy composite is described that can undergo an 88% reduction in flexural stiffness at elevated temperatures and fully recover when cooled, with no discernible damage or loss in properties. Once the stiffness has been reduced, the required deformations can be achieved at much lower actuation forces. For this proof-of-concept study a thin polyacrylamide (PAAm) layer was electrocoated onto carbon fibers that were then embedded into an epoxy matrix via resin infusion. Heating the PAAm coating above its glass transition temperature caused it to soften and allowed the fibers to slide within the matrix. To produce the stiffness change the carbon fibers were used as resistance heating elements by passing a current through them. When the PAAm coating had softened, the ability of the interphase to transfer load to the fibers was significantly reduced, greatly lowering the flexural stiffness of the composite. By changing the moisture content in PAAm fiber coating, the temperature at which the PAAm softens and the composites undergo a reduction in stiffness can be tuned. PMID:23978266

  3. Stability and control of maneuvering high-performance aircraft

    NASA Technical Reports Server (NTRS)

    Stengel, R. F.; Berry, P. W.

    1977-01-01

    The stability and control of a high-performance aircraft was analyzed, and a design methodology for a departure prevention stability augmentation system (DPSAS) was developed. A general linear aircraft model was derived which includes maneuvering flight effects and trim calculation procedures for investigating highly dynamic trajectories. The stability and control analysis systematically explored the effects of flight condition and angular motion, as well as the stability of typical air combat trajectories. The effects of configuration variation also were examined.

  4. TMD-Based Structural Control of High Performance Steel Bridges

    NASA Astrophysics Data System (ADS)

    Kim, Tae Min; Kim, Gun; Kyum Kim, Moon

    2012-08-01

    The purpose of this study is to investigate the effectiveness of structural control using tuned mass damper (TMD) for suppressing excessive traffic induced vibration of high performance steel bridge. The study considered 1-span steel plate girder bridge and bridge-vehicle interaction using HS-24 truck model. A numerical model of steel plate girder, traffic load, and TMD is constructed and time history analysis is performed using commercial structural analysis program ABAQUS 6.10. Results from analyses show that high performance steel bridge has dynamic serviceability problem, compared to relatively low performance steel bridge. Therefore, the structural control using TMD is implemented in order to alleviate dynamic serviceability problems. TMD is applied to the bridge with high performance steel and then vertical vibration due to dynamic behavior is assessed again. In consequent, by using TMD, it is confirmed that the residual amplitude is appreciably reduced by 85% in steady-state vibration. Moreover, vibration serviceability assessment using 'Reiher-Meister Curve' is also remarkably improved. As a result, this paper provides the guideline for economical design of I-girder using high performance steel and evaluates the effectiveness of structural control using TMD, simultaneously.

  5. X-31 high angle of attack control system performance

    NASA Technical Reports Server (NTRS)

    Huber, Peter; Seamount, Patricia

    1994-01-01

    The design goals for the X-31 flight control system were: (1) level 1 handling qualities during post-stall maneuvering (30 to 70 degrees angle-of-attack); (2) thrust vectoring to enhance performance across the flight envelope; and (3) adequate pitch-down authority at high angle-of-attack. Additional performance goals are discussed. A description of the flight control system is presented, highlighting flight control system features in the pitch and roll axes and X-31 thrust vectoring characteristics. The high angle-of-attack envelope clearance approach will be described, including a brief explanation of analysis techniques and tools. Also, problems encountered during envelope expansion will be discussed. This presentation emphasizes control system solutions to problems encountered in envelope expansion. An essentially 'care free' envelope was cleared for the close-in-combat demonstrator phase. High angle-of-attack flying qualities maneuvers are currently being flown and evaluated. These results are compared with pilot opinions expressed during the close-in-combat program and with results obtained from the F-18 HARV for identical maneuvers. The status and preliminary results of these tests are discussed.

  6. Switching LPV Control for High Performance Tactical Aircraft

    NASA Technical Reports Server (NTRS)

    Lu, Bei; Wu, Fen; Kim, SungWan

    2004-01-01

    This paper examines a switching Linear Parameter-Varying (LPV) control approach to determine if it is practical to use for flight control designs within a wide angle of attack region. The approach is based on multiple parameter-dependent Lyapunov functions. The full parameter space is partitioned into overlapping subspaces and a family of LPV controllers are designed, each suitable for a specific parameter subspace. The hysteresis switching logic is used to accomplish the transition among different parameter subspaces. The proposed switching LPV control scheme is applied to an F-16 aircraft model with different actuator dynamics in low and high angle of attack regions. The nonlinear simulation results show that the aircraft performs well when switching among different angle of attack regions.

  7. Robust high-performance control for robotic manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun (Inventor)

    1989-01-01

    Model-based and performance-based control techniques are combined for an electrical robotic control system. Thus, two distinct and separate design philosophies were merged into a single control system having a control law formulation including two distinct and separate components, each of which yields a respective signal componet that is combined into a total command signal for the system. Those two separate system components include a feedforward controller and feedback controller. The feedforward controller is model-based and contains any known part of the manipulator dynamics that can be used for on-line control to produce a nominal feedforward component of the system's control signal. The feedback controller is performance-based and consists of a simple adaptive PID controller which generates an adaptive control signal to complement the nomical feedforward signal.

  8. Robust high-performance control for robotic manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun (Inventor)

    1991-01-01

    Model-based and performance-based control techniques are combined for an electrical robotic control system. Thus, two distinct and separate design philosophies have been merged into a single control system having a control law formulation including two distinct and separate components, each of which yields a respective signal component that is combined into a total command signal for the system. Those two separate system components include a feedforward controller and a feedback controller. The feedforward controller is model-based and contains any known part of the manipulator dynamics that can be used for on-line control to produce a nominal feedforward component of the system's control signal. The feedback controller is performance-based and consists of a simple adaptive PID controller which generates an adaptive control signal to complement the nominal feedforward signal.

  9. Control Software for a High-Performance Telerobot

    NASA Technical Reports Server (NTRS)

    Kline-Schoder, Robert J.; Finger, William

    2005-01-01

    A computer program for controlling a high-performance, force-reflecting telerobot has been developed. The goal in designing a telerobot-control system is to make the velocity of the slave match the master velocity, and the environmental force on the master match the force on the slave. Instability can arise from even small delays in propagation of signals between master and slave units. The present software, based on an impedance-shaping algorithm, ensures stability even in the presence of long delays. It implements a real-time algorithm that processes position and force measurements from the master and slave and represents the master/slave communication link as a transmission line. The algorithm also uses the history of the control force and the slave motion to estimate the impedance of the environment. The estimate of the impedance of the environment is used to shape the controlled slave impedance to match the transmission-line impedance. The estimate of the environmental impedance is used to match the master and transmission-line impedances and to estimate the slave/environment force in order to present that force immediately to the operator via the master unit.

  10. Archon: A modern controller for high performance astronomical CCDs

    NASA Astrophysics Data System (ADS)

    Bredthauer, Greg

    2014-08-01

    The rapid evolution of commercial FPGAs and analog ICs has enabled the development of Archon, a new modular high performance astronomical CCD controller. CCD outputs are digitized by 16-bit 100 MHz ADCs with differential AC-coupled preamplifiers. The raw data stream from an ADC can be stored in parallel with standard image data into three onboard 512 MB frame buffers. Pixel values are computed using digital correlated double sampling. At low pixel rates (< 1 MHz), the dynamic range achievable by averaging hundreds of ADC samples per pixel can exceed 16 bits, so an option to store 32 bits per pixel is provided. CCD clocks are generated by 14-bit 100 MHz DACs. The scripted timing core driving the clocks can generate a new target voltage for each clock every 10 ns, and the clock slew rates are individually programmable. CCD biases are derived from 16-bit DACs, are continuously monitored for voltage and current, and power up and down in a customizable sequence. Communication between the controller and a host computer occurs over a gigabit Ethernet interface (fiber or copper). A CCD configuration is specified by a simple text file. Together, these features simplify the tuning and debugging of scientific CCDs, and enable CCD-limited imaging. I present details of the controller architecture, examples of CCD tuning, and measured performance data of the controller alone (dynamic range of 108 dB at 100 kHz and 98 dB at 1 MHz) and in combination with an STA1600LN CCD.

  11. Toward high performance radioisotope thermophotovoltaic systems using spectral control

    NASA Astrophysics Data System (ADS)

    Wang, Xiawa; Chan, Walker; Stelmakh, Veronika; Celanovic, Ivan; Fisher, Peter

    2016-12-01

    This work describes RTPV-PhC-1, an initial prototype for a radioisotope thermophotovoltaic (RTPV) system using a two-dimensional photonic crystal emitter and low bandgap thermophotovoltaic (TPV) cell to realize spectral control. We validated a system simulation using the measurements of RTPV-PhC-1 and its comparison setup RTPV-FlatTa-1 with the same configuration except a polished tantalum emitter. The emitter of RTPV-PhC-1 powered by an electric heater providing energy equivalent to one plutonia fuel pellet reached 950 °C with 52 W of thermal input power and produced 208 mW output power from 1 cm2 TPV cell. We compared the system performance using a photonic crystal emitter to a polished flat tantalum emitter and found that spectral control with the photonic crystal was four times more efficient. Based on the simulation, with more cell areas, better TPV cells, and improved insulation design, the system powered by a fuel pellet equivalent heat source is expected to reach an efficiency of 7.8%.

  12. Robust high-performance control for robotic manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1989-01-01

    A robust control scheme to accomplish accurate trajectory tracking for an integrated system of manipulator-plus-actuators is proposed. The control scheme comprises a feedforward and a feedback controller. The feedforward controller contains any known part of the manipulator dynamics that can be used for online control. The feedback controller consists of adaptive position and velocity feedback gains and an auxiliary signal which is simply generated by a fixed-gain proportional/integral/derivative controller. The feedback controller is updated by very simple adaptation laws which contain both proportional and integral adaptation terms. By introduction of a simple sigma modification to the adaptation laws, robustness is guaranteed in the presence of unmodeled dynamics and disturbances.

  13. Nonlinear stability and control study of highly maneuverable high performance aircraft

    NASA Technical Reports Server (NTRS)

    Mohler, R. R.

    1993-01-01

    This project is intended to research and develop new nonlinear methodologies for the control and stability analysis of high-performance, high angle-of-attack aircraft such as HARV (F18). Past research (reported in our Phase 1, 2, and 3 progress reports) is summarized and more details of final Phase 3 research is provided. While research emphasis is on nonlinear control, other tasks such as associated model development, system identification, stability analysis, and simulation are performed in some detail as well. An overview of various models that were investigated for different purposes such as an approximate model reference for control adaptation, as well as another model for accurate rigid-body longitudinal motion is provided. Only a very cursory analysis was made relative to type 8 (flexible body dynamics). Standard nonlinear longitudinal airframe dynamics (type 7) with the available modified F18 stability derivatives, thrust vectoring, actuator dynamics, and control constraints are utilized for simulated flight evaluation of derived controller performance in all cases studied.

  14. Investigation of High-alpha Lateral-directional Control Power Requirements for High-performance Aircraft

    NASA Technical Reports Server (NTRS)

    Foster, John V.; Ross, Holly M.; Ashley, Patrick A.

    1993-01-01

    Designers of the next-generation fighter and attack airplanes are faced with the requirements of good high-angle-of-attack maneuverability as well as efficient high speed cruise capability with low radar cross section (RCS) characteristics. As a result, they are challenged with the task of making critical design trades to achieve the desired levels of maneuverability and performance. This task has highlighted the need for comprehensive, flight-validated lateral-directional control power design guidelines for high angles of attack. A joint NASA/U.S. Navy study has been initiated to address this need and to investigate the complex flight dynamics characteristics and controls requirements for high-angle-of-attack lateral-directional maneuvering. A multi-year research program is underway which includes ground-based piloted simulation and flight validation. This paper will give a status update of this program that will include a program overview, description of test methodology and preliminary results.

  15. Investigation of high-alpha lateral-directional control power requirements for high-performance aircraft

    NASA Technical Reports Server (NTRS)

    Foster, John V.; Ross, Holly M.; Ashley, Patrick A.

    1993-01-01

    Designers of the next-generation fighter and attack airplanes are faced with the requirements of good high angle-of-attack maneuverability as well as efficient high speed cruise capability with low radar cross section (RCS) characteristics. As a result, they are challenged with the task of making critical design trades to achieve the desired levels of maneuverability and performance. This task has highlighted the need for comprehensive, flight-validated lateral-directional control power design guidelines for high angles of attack. A joint NASA/U.S. Navy study has been initiated to address this need and to investigate the complex flight dynamics characteristics and controls requirements for high angle-of-attack lateral-directional maneuvering. A multi-year research program is underway which includes groundbased piloted simulation and flight validation. This paper will give a status update of this program that will include a program overview, description of test methodology and preliminary results.

  16. Performance seeking control (PSC) for the F-15 highly integrated digital electronic control (HIDEC) aircraft

    NASA Technical Reports Server (NTRS)

    Orme, John S.

    1995-01-01

    The performance seeking control algorithm optimizes total propulsion system performance. This adaptive, model-based optimization algorithm has been successfully flight demonstrated on two engines with differing levels of degradation. Models of the engine, nozzle, and inlet produce reliable, accurate estimates of engine performance. But, because of an observability problem, component levels of degradation cannot be accurately determined. Depending on engine-specific operating characteristics PSC achieves various levels performance improvement. For example, engines with more deterioration typically operate at higher turbine temperatures than less deteriorated engines. Thus when the PSC maximum thrust mode is applied, for example, there will be less temperature margin available to be traded for increasing thrust.

  17. Application of digital servo control on high-performance VCM in HDD

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Gang; Lin, Ming-Jer

    1992-10-01

    An application of digital servo control on a high-performance voice coil motor positioning system in hard disk drive is discussed. Modern digital control theory is used in servo algorithm design, and the servo algorithm is implemented by a high-speed microprocessor, OES 22040 model. The experimental results show the excellent properties in time domain and frequency domain.

  18. Nonlinear stability and control study of highly maneuverable high performance aircraft

    NASA Technical Reports Server (NTRS)

    Mohler, R. R.

    1991-01-01

    The purpose was to develop and apply new nonlinear system methodologies to the stability analysis and adaptive control of high angle of attack (alpha) aircraft such as the F-18. Considerable progress is documented on nonlinear adaptive control and associated model development, identification, and simulation. The analysis considered linear and nonlinear, longitudinal, high alpha aircraft dynamics with varying degrees of approximation dependent on the purpose. In all cases, angle of attack or pitch rate was controlled primarily by a horizontal stabilizer. In most cases studied, a linear adaptive controller provided sufficient stability. However, it has been demonstrated by simulation of a simplified nonlinear model that certain large rapid maneuvers were not readily stabilized by the investigated linear adaptive control, but were controlled instead by means of a nonlinear time-series based adaptive control.

  19. High Performance, Robust Control of Flexible Space Structures: MSFC Center Director's Discretionary Fund

    NASA Technical Reports Server (NTRS)

    Whorton, M. S.

    1998-01-01

    Many spacecraft systems have ambitious objectives that place stringent requirements on control systems. Achievable performance is often limited because of difficulty of obtaining accurate models for flexible space structures. To achieve sufficiently high performance to accomplish mission objectives may require the ability to refine the control design model based on closed-loop test data and tune the controller based on the refined model. A control system design procedure is developed based on mixed H2/H(infinity) optimization to synthesize a set of controllers explicitly trading between nominal performance and robust stability. A homotopy algorithm is presented which generates a trajectory of gains that may be implemented to determine maximum achievable performance for a given model error bound. Examples show that a better balance between robustness and performance is obtained using the mixed H2/H(infinity) design method than either H2 or mu-synthesis control design. A second contribution is a new procedure for closed-loop system identification which refines parameters of a control design model in a canonical realization. Examples demonstrate convergence of the parameter estimation and improved performance realized by using the refined model for controller redesign. These developments result in an effective mechanism for achieving high-performance control of flexible space structures.

  20. High-performance control system for a heavy-ion medical accelerator

    SciTech Connect

    Lancaster, H.D.; Magyary, S.B.; Sah, R.C.

    1983-03-01

    A high performance control system is being designed as part of a heavy ion medical accelerator. The accelerator will be a synchrotron dedicated to clinical and other biomedical uses of heavy ions, and it will deliver fully stripped ions at energies up to 800 MeV/nucleon. A key element in the design of an accelerator which will operate in a hospital environment is to provide a high performance control system. This control system will provide accelerator modeling to facilitate changes in operating mode, provide automatic beam tuning to simplify accelerator operations, and provide diagnostics to enhance reliability. The control system being designed utilizes many microcomputers operating in parallel to collect and transmit data; complex numerical computations are performed by a powerful minicomputer. In order to provide the maximum operational flexibility, the Medical Accelerator control system will be capable of dealing with pulse-to-pulse changes in beam energy and ion species.

  1. Dynamic neural networks based on-line identification and control of high performance motor drives

    NASA Technical Reports Server (NTRS)

    Rubaai, Ahmed; Kotaru, Raj

    1995-01-01

    In the automated and high-tech industries of the future, there wil be a need for high performance motor drives both in the low-power range and in the high-power range. To meet very straight demands of tracking and regulation in the two quadrants of operation, advanced control technologies are of a considerable interest and need to be developed. In response a dynamics learning control architecture is developed with simultaneous on-line identification and control. the feature of the proposed approach, to efficiently combine the dual task of system identification (learning) and adaptive control of nonlinear motor drives into a single operation is presented. This approach, therefore, not only adapts to uncertainties of the dynamic parameters of the motor drives but also learns about their inherent nonlinearities. In fact, most of the neural networks based adaptive control approaches in use have an identification phase entirely separate from the control phase. Because these approaches separate the identification and control modes, it is not possible to cope with dynamic changes in a controlled process. Extensive simulation studies have been conducted and good performance was observed. The robustness characteristics of neuro-controllers to perform efficiently in a noisy environment is also demonstrated. With this initial success, the principal investigator believes that the proposed approach with the suggested neural structure can be used successfully for the control of high performance motor drives. Two identification and control topologies based on the model reference adaptive control technique are used in this present analysis. No prior knowledge of load dynamics is assumed in either topology while the second topology also assumes no knowledge of the motor parameters.

  2. Design of a new high-performance pointing controller for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Johnson, C. D.

    1993-01-01

    A new form of high-performance, disturbance-adaptive pointing controller for the Hubble Space Telescope (HST) is proposed. This new controller is all linear (constant gains) and can maintain accurate 'pointing' of the HST in the face of persistent randomly triggered uncertain, unmeasurable 'flapping' motions of the large attached solar array panels. Similar disturbances associated with antennas and other flexible appendages can also be accommodated. The effectiveness and practicality of the proposed new controller is demonstrated by a detailed design and simulation testing of one such controller for a planar-motion, fully nonlinear model of HST. The simulation results show a high degree of disturbance isolation and pointing stability.

  3. Design of high performance multivariable control systems for supermaneuverable aircraft at high angle of attack

    NASA Technical Reports Server (NTRS)

    Valavani, Lena

    1995-01-01

    The main motivation for the work under the present grant was to use nonlinear feedback linearization methods to further enhance performance capabilities of the aircraft, and robustify its response throughout its operating envelope. The idea was to use these methods in lieu of standard Taylor series linearization, in order to obtain a well behaved linearized plant, in its entire operational regime. Thus, feedback linearization was going to constitute an 'inner loop', which would then define a 'design plant model' to be compensated for robustness and guaranteed performance in an 'outer loop' application of modern linear control methods. The motivation for this was twofold; first, earlier work had shown that by appropriately conditioning the plant through conventional, simple feedback in an 'inner loop', the resulting overall compensated plant design enjoyed considerable enhancement of performance robustness in the presence of parametric uncertainty. Second, the nonlinear techniques did not have any proven robustness properties in the presence of unstructured uncertainty; a definition of robustness (and performance) is very difficult to achieve outside the frequency domain; to date, none is available for the purposes of control system design. Thus, by proper design of the outer loop, such properties could still be 'injected' in the overall system.

  4. Combined dynamic inversion and QFT flight control of an unstable high performance aircraft

    NASA Astrophysics Data System (ADS)

    Stout, Perry Walter

    Quantitative Feedback Theory (QFT) is a control system synthesis, technique that directly considers system uncertainties and disturbance magnitudes when formulating closed-loop control algorithms. Dynamic Inversion is a nonlinear control system design technique that relies on accurate mathematical models to compute control inputs producing arbitrary system responses. Both techniques have been applied to unstable high performance aircraft flight control, and produced effective aircraft controllers. Both techniques have certain drawbacks: Nonlinear QFT controllers tend to be unnecessarily conservative (the computed controllers have excessive bandwidth) because known system properties are treated as "unknown" disturbances during loop synthesis. Meanwhile Dynamic Inversion control is sensitive to differences between assumed mathematical models and actual system dynamic properties. Combining the two control techniques provides the benefit of both while suffering the drawbacks of neither, as demonstrated by Single Input, Single Output (SISO) control of a constant airspeed, no roll, no yaw nonlinear model of the F-16 aircraft, and by Multi-Input, Multi-Output (MIMO) control of a full six-degree-of-freedom version. Design performance of the combined controllers is verified by reduced actuator efforts and by reduced sensor noise to actuator input (U( s)/n(s)) transfer function magnitudes compared to standard QFT versions.

  5. Damage-Mitigating Control of Space Propulsion Systems for High Performance and Extended Life

    NASA Technical Reports Server (NTRS)

    Ray, Asok; Wu, Min-Kuang

    1994-01-01

    A major goal in the control of complex mechanical system such as spacecraft rocket engine's advanced aircraft, and power plants is to achieve high performance with increased reliability, component durability, and maintainability. The current practice of decision and control systems synthesis focuses on improving performance and diagnostic capabilities under constraints that often do not adequately represent the materials degradation. In view of the high performance requirements of the system and availability of improved materials, the lack of appropriate knowledge about the properties of these materials will lead to either less than achievable performance due to overly conservative design, or over-straining of the structure leading to unexpected failures and drastic reduction of the service life. The key idea in this report is that a significant improvement in service life could be achieved by a small reduction in the system dynamic performance. The major task is to characterize the damage generation process, and then utilize this information in a mathematical form to synthesize a control law that would meet the system requirements and simultaneously satisfy the constraints that are imposed by the material and structural properties of the critical components. The concept of damage mitigation is introduced for control of mechanical systems to achieve high performance with a prolonged life span. A model of fatigue damage dynamics is formulated in the continuous-time setting, instead of a cycle-based representation, for direct application to control systems synthesis. An optimal control policy is then formulated via nonlinear programming under specified constraints of the damage rate and accumulated damage. The results of simulation experiments for the transient upthrust of a bipropellant rocket engine are presented to demonstrate efficacy of the damage-mitigating control concept.

  6. Expert Meeting: Recommended Approaches to Humidity Control in High Performance Homes

    SciTech Connect

    Rudd, A.

    2013-07-01

    The topic of this Building America expert meeting was 'Recommended Approaches to Humidity Control in High Performance Homes,' which was held on October 16, 2012, in Westford, MA, and brought together experts in the field of residential humidity control to address modeling issues for dehumidification. The presentations and discussions centered on computer simulation and field experience with these systems, with the goal of developing foundational information to support the development of a Building America Measure Guideline on this topic.

  7. High-Performance Integrated Control of water quality and quantity in urban water reservoirs

    NASA Astrophysics Data System (ADS)

    Galelli, S.; Castelletti, A.; Goedbloed, A.

    2015-11-01

    This paper contributes a novel High-Performance Integrated Control framework to support the real-time operation of urban water supply storages affected by water quality problems. We use a 3-D, high-fidelity simulation model to predict the main water quality dynamics and inform a real-time controller based on Model Predictive Control. The integration of the simulation model into the control scheme is performed by a model reduction process that identifies a low-order, dynamic emulator running 4 orders of magnitude faster. The model reduction, which relies on a semiautomatic procedural approach integrating time series clustering and variable selection algorithms, generates a compact and physically meaningful emulator that can be coupled with the controller. The framework is used to design the hourly operation of Marina Reservoir, a 3.2 Mm3 storm-water-fed reservoir located in the center of Singapore, operated for drinking water supply and flood control. Because of its recent formation from a former estuary, the reservoir suffers from high salinity levels, whose behavior is modeled with Delft3D-FLOW. Results show that our control framework reduces the minimum salinity levels by nearly 40% and cuts the average annual deficit of drinking water supply by about 2 times the active storage of the reservoir (about 4% of the total annual demand).

  8. Robust Damage-Mitigating Control of Aircraft for High Performance and Structural Durability

    NASA Technical Reports Server (NTRS)

    Caplin, Jeffrey; Ray, Asok; Joshi, Suresh M.

    1999-01-01

    This paper presents the concept and a design methodology for robust damage-mitigating control (DMC) of aircraft. The goal of DMC is to simultaneously achieve high performance and structural durability. The controller design procedure involves consideration of damage at critical points of the structure, as well as the performance requirements of the aircraft. An aeroelastic model of the wings has been formulated and is incorporated into a nonlinear rigid-body model of aircraft flight-dynamics. Robust damage-mitigating controllers are then designed using the H(infinity)-based structured singular value (mu) synthesis method based on a linearized model of the aircraft. In addition to penalizing the error between the ideal performance and the actual performance of the aircraft, frequency-dependent weights are placed on the strain amplitude at the root of each wing. Using each controller in turn, the control system is put through an identical sequence of maneuvers, and the resulting (varying amplitude cyclic) stress profiles are analyzed using a fatigue crack growth model that incorporates the effects of stress overload. Comparisons are made to determine the impact of different weights on the resulting fatigue crack damage in the wings. The results of simulation experiments show significant savings in fatigue life of the wings while retaining the dynamic performance of the aircraft.

  9. Damage-mitigating control of aircraft for high performance and life extension

    NASA Astrophysics Data System (ADS)

    Caplin, Jeffrey

    1998-12-01

    A methodology is proposed for the synthesis of a Damage-Mitigating Control System for a high-performance fighter aircraft. The design of such a controller involves consideration of damage to critical points of the structure, as well as the performance requirements of the aircraft. This research is interdisciplinary, and brings existing knowledge in the fields of unsteady aerodynamics, structural dynamics, fracture mechanics, and control theory together to formulate a new approach towards aircraft flight controller design. A flexible wing model is formulated using the Finite Element Method, and the important mode shapes and natural frequencies are identified. The Doublet Lattice Method is employed to develop an unsteady flow model for computation of the unsteady aerodynamic loads acting on the wing due to rigid-body maneuvers and structural deformation. These two models are subsequently incorporated into a pre-existing nonlinear rigid-body aircraft flight-dynamic model. A family of robust Damage-Mitigating Controllers is designed using the Hinfinity-optimization and mu-synthesis method. In addition to weighting the error between the ideal performance and the actual performance of the aircraft, weights are also placed on the strain amplitude at the root of each wing. The results show significant savings in fatigue life of the wings while retaining the dynamic performance of the aircraft.

  10. An experimental study of concurrent methods for adaptively controlling vertical tail buffet in high performance aircraft

    NASA Astrophysics Data System (ADS)

    Roberts, Patrick J.

    High performance twin-tail aircraft, like the F-15 and F/A-18, encounter a condition known as tail buffet. At high angles of attack, vortices are generated at the wing fuselage interface (shoulder) or other leading edge extensions. These vortices are directed toward the twin vertical tails. When the flow interacts with the vertical tail it creates pressure variations that can oscillate the vertical tail assembly. This results in fatigue cracks in the vertical tail assembly that can decrease the fatigue life and increase maintenance costs. Recently, an offset piezoceramic stack actuator was used on an F-15 wind tunnel model to control buffet induced vibrations at high angles of attack. The controller was based on the acceleration feedback control methods, In this thesis a procedure for designing the offset piezoceramic stack actuators is developed. This design procedure includes determining the quantity and type of piezoceramic stacks used in these actuators. The changes of stresses, in the vertical tail caused by these actuators during an active control, are investigated. In many cases, linear controllers are very effective in reducing vibrations. However, during flight, the natural frequencies of the vertical tail structural system changes as the airspeed increases. This in turn, reduces the effectiveness of a linear controller. Other causes such as the unmodeled dynamics and nonlinear effects due to debonds also reduce the effectiveness of linear controllers. In this thesis, an adaptive neural network is used to augment the linear controller to correct these effects.

  11. Astronomical imaging with L3CCDs: detector performance and high-speed controller design

    NASA Astrophysics Data System (ADS)

    Mackay, Craig; Basden, Alistair; Bridgeland, Mick

    2004-09-01

    L3CCDs represent a major step in CCD performance with great potential for astronomical applications because of their ability to work at very high pixel rates with negligible readout noise. This paper describes the results of tests on some of the L3CCDs now available and discusses how the operating conditions may be optimised for a variety of different applications. In particular, at high gain they can be used for photon counting work at photon rates well in excess of one photon per pixel per second. Readout rates which can be as high as 35MHz are entirely practical for a number of astronomical applications. This paper describes some of the compromises and trade-offs that have to be made in designing high-speed controllers to work effectively with these devices. The importance of integrating high-speed controllers for astronomy with significant amount of real-time processing power is also discussed.

  12. Performance improvements of a highly integrated digital electronic control system for an F-15 airplane

    NASA Technical Reports Server (NTRS)

    Putnam, T. W.; Burcham, F. W., Jr.; Andries, M. G.; Kelly, J. B.

    1985-01-01

    The NASA highly integrated digital electronic control (HIDEC) program is structured to conduct flight research into the benefits of integrating an aircraft flight control system with the engine control system. A brief description of the HIDEC system installed on an F-15 aircraft is provided. The adaptive engine control system (ADECS) mode is described in detail, together with simulation results and analyses that show the significant excess thrust improvements achievable with the ADECS mode. It was found that this increased thrust capability is accompanied by reduced fan stall margin and can be realized during flight conditions where engine face distortion is low. The results of analyses and simulations also show that engine thrust response is improved and that fuel consumption can be reduced. Although the performance benefits that accrue because of airframe and engine control integration are being demonstrated on an F-15 aircraft, the principles are applicable to advanced aircraft such as the advanced tactical fighter and advanced tactical aircraft.

  13. Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

    NASA Astrophysics Data System (ADS)

    Han, Yung-Min; Han, Chulhee; Kim, Wan Ho; Seong, Ho Yong; Choi, Seung-Bok

    2016-09-01

    This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.

  14. Compact high-performance MWIR camera with exposure control and 12-bit video processor

    NASA Astrophysics Data System (ADS)

    Villani, Thomas S.; Loesser, Kenneth A.; Perna, Steve N.; McCarthy, D. R.; Pantuso, Francis P.

    1998-07-01

    The design and performance of a compact infrared camera system is presented. The 3 - 5 micron MWIR imaging system consists of a Stirling-cooled 640 X 480 staring PtSi infrared focal plane array (IRFPA) with a compact, high-performance 12-bit digital image processor. The low-noise CMOS IRFPA is X-Y addressable, utilizes on-chip-scanning registers and has electronic exposure control. The digital image processor uses 16-frame averaged, 2-point non-uniformity compensation and defective pixel substitution circuitry. There are separate 12- bit digital and analog I/O ports for display control and video output. The versatile camera system can be configured in NTSC, CCIR, and progressive scan readout formats and the exposure control settings are digitally programmable.

  15. New Technique of High-Performance Torque Control Developed for Induction Machines

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.

    2003-01-01

    Two forms of high-performance torque control for motor drives have been described in the literature: field orientation control and direct torque control. Field orientation control has been the method of choice for previous NASA electromechanical actuator research efforts with induction motors. Direct torque control has the potential to offer some advantages over field orientation, including ease of implementation and faster response. However, the most common form of direct torque control is not suitable for the highspeed, low-stator-flux linkage induction machines designed for electromechanical actuators with the presently available sample rates of digital control systems (higher sample rates are required). In addition, this form of direct torque control is not suitable for the addition of a high-frequency carrier signal necessary for the "self-sensing" (sensorless) position estimation technique. This technique enables low- and zero-speed position sensorless operation of the machine. Sensorless operation is desirable to reduce the number of necessary feedback signals and transducers, thus improving the reliability and reducing the mass and volume of the system. This research was directed at developing an alternative form of direct torque control known as a "deadbeat," or inverse model, solution. This form uses pulse-width modulation of the voltage applied to the machine, thus reducing the necessary sample and switching frequency for the high-speed NASA motor. In addition, the structure of the deadbeat form allows the addition of the high-frequency carrier signal so that low- and zero-speed sensorless operation is possible. The new deadbeat solution is based on using the stator and rotor flux as state variables. This choice of state variables leads to a simple graphical representation of the solution as the intersection of a constant torque line with a constant stator flux circle. Previous solutions have been expressed only in complex mathematical terms without a

  16. High-Achieving High School Students and Not so High-Achieving College Students: A Look at Lack of Self-Control, Academic Ability, and Performance in College

    ERIC Educational Resources Information Center

    Honken, Nora B.; Ralston, Patricia A. S.

    2013-01-01

    This study investigated the relationship among lack of self-control, academic ability, and academic performance for a cohort of freshman engineering students who were, with a few exceptions, extremely high achievers in high school. Structural equation modeling analysis led to the conclusion that lack of self-control in high school, as measured by…

  17. Innovative use of controlled availability fertilizers with high performance for intensive agriculture and environmental conservation.

    PubMed

    Shoji, Sadao

    2005-12-01

    A variety of slow release fertilizers, controlled release (availability) fertilizers (CAFs), and stability fertilizers have been developed in response to the serious drawbacks of the conventional fertilizers since the early 1960's. Of these fertilizers, CAFs which are coated with resin are consumed in the largest quantity in the world. Selecting CAFs with higher performance, the author will discuss about: 1) Innovation of agro-technologies for various field crops including new concepts of fertilizer application, 2) high yielding of field crops, 3) enhancing quality and safety of farm products, and 4) controlling the adverse effect of intensive agriculture on the environment. PMID:16512212

  18. Innovative use of controlled availability fertilizers with high performance for intensive agriculture and environmental conservation.

    PubMed

    Shoji, Sadao

    2005-09-01

    A variety of slow release fertilizers, controlled release (availability) fertilizers (CAFs), and stability fertilizers have been developed in response to the serious drawbacks of the conventional fertilizers since the early 1960's. Of these fertilizers, CAFs which are coated with resin are consumed in the largest quantity in the world. Selecting CAFs with higher performance, the author will discuss about: 1) Innovation of agro-technologies for various field crops including new concepts of fertilizer application, 2) high yielding of field crops, 3) enhancing quality and safety of farm products, and 4) controlling the adverse effect of intensive agriculture on the environment. PMID:20549445

  19. Innovative use of controlled availability fertilizers with high performance for intensive agriculture and environmental conservation.

    PubMed

    Shoji, Sadao

    2005-09-01

    A variety of slow release fertilizers, controlled release (availability) fertilizers (CAFs), and stability fertilizers have been developed in response to the serious drawbacks of the conventional fertilizers since the early 1960's. Of these fertilizers, CAFs which are coated with resin are consumed in the largest quantity in the world. Selecting CAFs with higher performance, the author will discuss about: 1) Innovation of agro-technologies for various field crops including new concepts of fertilizer application, 2) high yielding of field crops, 3) enhancing quality and safety of farm products, and 4) controlling the adverse effect of intensive agriculture on the environment.

  20. Innovative use of controlled availability fertilizers with high performance for intensive agriculture and environmental conservation.

    PubMed

    Shoji, Sadao

    2005-12-01

    A variety of slow release fertilizers, controlled release (availability) fertilizers (CAFs), and stability fertilizers have been developed in response to the serious drawbacks of the conventional fertilizers since the early 1960's. Of these fertilizers, CAFs which are coated with resin are consumed in the largest quantity in the world. Selecting CAFs with higher performance, the author will discuss about: 1) Innovation of agro-technologies for various field crops including new concepts of fertilizer application, 2) high yielding of field crops, 3) enhancing quality and safety of farm products, and 4) controlling the adverse effect of intensive agriculture on the environment.

  1. Intelligent adaptive nonlinear flight control for a high performance aircraft with neural networks.

    PubMed

    Savran, Aydogan; Tasaltin, Ramazan; Becerikli, Yasar

    2006-04-01

    This paper describes the development of a neural network (NN) based adaptive flight control system for a high performance aircraft. The main contribution of this work is that the proposed control system is able to compensate the system uncertainties, adapt to the changes in flight conditions, and accommodate the system failures. The underlying study can be considered in two phases. The objective of the first phase is to model the dynamic behavior of a nonlinear F-16 model using NNs. Therefore a NN-based adaptive identification model is developed for three angular rates of the aircraft. An on-line training procedure is developed to adapt the changes in the system dynamics and improve the identification accuracy. In this procedure, a first-in first-out stack is used to store a certain history of the input-output data. The training is performed over the whole data in the stack at every stage. To speed up the convergence rate and enhance the accuracy for achieving the on-line learning, the Levenberg-Marquardt optimization method with a trust region approach is adapted to train the NNs. The objective of the second phase is to develop intelligent flight controllers. A NN-based adaptive PID control scheme that is composed of an emulator NN, an estimator NN, and a discrete time PID controller is developed. The emulator NN is used to calculate the system Jacobian required to train the estimator NN. The estimator NN, which is trained on-line by propagating the output error through the emulator, is used to adjust the PID gains. The NN-based adaptive PID control system is applied to control three angular rates of the nonlinear F-16 model. The body-axis pitch, roll, and yaw rates are fed back via the PID controllers to the elevator, aileron, and rudder actuators, respectively. The resulting control system has learning, adaptation, and fault-tolerant abilities. It avoids the storage and interpolation requirements for the too many controller parameters of a typical flight control

  2. Intelligent adaptive nonlinear flight control for a high performance aircraft with neural networks.

    PubMed

    Savran, Aydogan; Tasaltin, Ramazan; Becerikli, Yasar

    2006-04-01

    This paper describes the development of a neural network (NN) based adaptive flight control system for a high performance aircraft. The main contribution of this work is that the proposed control system is able to compensate the system uncertainties, adapt to the changes in flight conditions, and accommodate the system failures. The underlying study can be considered in two phases. The objective of the first phase is to model the dynamic behavior of a nonlinear F-16 model using NNs. Therefore a NN-based adaptive identification model is developed for three angular rates of the aircraft. An on-line training procedure is developed to adapt the changes in the system dynamics and improve the identification accuracy. In this procedure, a first-in first-out stack is used to store a certain history of the input-output data. The training is performed over the whole data in the stack at every stage. To speed up the convergence rate and enhance the accuracy for achieving the on-line learning, the Levenberg-Marquardt optimization method with a trust region approach is adapted to train the NNs. The objective of the second phase is to develop intelligent flight controllers. A NN-based adaptive PID control scheme that is composed of an emulator NN, an estimator NN, and a discrete time PID controller is developed. The emulator NN is used to calculate the system Jacobian required to train the estimator NN. The estimator NN, which is trained on-line by propagating the output error through the emulator, is used to adjust the PID gains. The NN-based adaptive PID control system is applied to control three angular rates of the nonlinear F-16 model. The body-axis pitch, roll, and yaw rates are fed back via the PID controllers to the elevator, aileron, and rudder actuators, respectively. The resulting control system has learning, adaptation, and fault-tolerant abilities. It avoids the storage and interpolation requirements for the too many controller parameters of a typical flight control

  3. Freeze-drying for morphological control of high performance semi-interpenetrating polymer networks. III

    NASA Technical Reports Server (NTRS)

    Hsiung, H. J.; Hansen, M. G.; Pater, R. H.

    1991-01-01

    The feasibility of using a freeze-drying (solvent removal by sublimation) approach for controlling the morphology of a high-performance semi-IPN is assessed. A high-performance thermoplastic polyimide and commercially available 4,4'-bismaleimide diphenylenemethane were dissolved in a solvent, 1,3,5-trioxane. The solvent was removed from the constituents by freeze-drying. For purposes of comparison, the constituents were dissolved in a high-boiling-point solvent, N,N-dimethylformamide. The solvent was removed from the solution by evaporation. The physical and mechanical properties and phase morphology of the neat resins and composites prepared by freeze-drying and traditional solution methods are presented and compared. It is concluded that the TG is higher and that the magnitude of minor constituent separation is less in the freeze-dry processed materials than for the processed solution.

  4. A Modified Lunar Reconnaissance Orbiter (LRO) High Gain Antenna (HGA) Controller Based on Flight Performance

    NASA Technical Reports Server (NTRS)

    Shah, Neerav

    2010-01-01

    The National Aeronautics and Space Administration's (NASA) Lunar Reconnaissance Orbiter (LRO) was launched on June 18, 2009 and is currently in a 50 km mean altitude polar orbit around the Moon. LRO was designed and built by the NASA Goddard Space Flight Center in Greenbelt, MD. The spacecraft is three-axis stabilized via the attitude control system (ACS), which is composed of various control modes using different sets of sensors and actuators. In addition to pointing the spacecraft, the ACS is responsible for pointing LRO s two appendages, the Solar Array (SA) and the High Gain Antenna (HGA). This study reviews LRO s HGA control system. Starting with an overview of the HGA system, the paper delves into the single input single output (SISO) linear analysis followed by the controller design. Based on flight results, an alternate control scheme is devised to address inherent features in the flight control system. The modified control scheme couples the HGA loop with the spacecraft pointing control loop, and through analysis is shown to be stable and improve transient performance. Although proposed, the LRO project decided against implementing this modification.

  5. High-performance computing-based exploration of flow control with micro devices.

    PubMed

    Fujii, Kozo

    2014-08-13

    The dielectric barrier discharge (DBD) plasma actuator that controls flow separation is one of the promising technologies to realize energy savings and noise reduction of fluid dynamic systems. However, the mechanism for controlling flow separation is not clearly defined, and this lack of knowledge prevents practical use of this technology. Therefore, large-scale computations for the study of the DBD plasma actuator have been conducted using the Japanese Petaflops supercomputer 'K' for three different Reynolds numbers. Numbers of new findings on the control of flow separation by the DBD plasma actuator have been obtained from the simulations, and some of them are presented in this study. Knowledge of suitable device parameters is also obtained. The DBD plasma actuator is clearly shown to be very effective for controlling flow separation at a Reynolds number of around 10(5), and several times larger lift-to-drag ratio can be achieved at higher angles of attack after stall. For higher Reynolds numbers, separated flow is partially controlled. Flow analysis shows key features towards better control. DBD plasma actuators are a promising technology, which could reduce fuel consumption and contribute to a green environment by achieving high aerodynamic performance. The knowledge described above can be obtained only with high-end computers such as the supercomputer 'K'.

  6. High-performance computing-based exploration of flow control with micro devices.

    PubMed

    Fujii, Kozo

    2014-08-13

    The dielectric barrier discharge (DBD) plasma actuator that controls flow separation is one of the promising technologies to realize energy savings and noise reduction of fluid dynamic systems. However, the mechanism for controlling flow separation is not clearly defined, and this lack of knowledge prevents practical use of this technology. Therefore, large-scale computations for the study of the DBD plasma actuator have been conducted using the Japanese Petaflops supercomputer 'K' for three different Reynolds numbers. Numbers of new findings on the control of flow separation by the DBD plasma actuator have been obtained from the simulations, and some of them are presented in this study. Knowledge of suitable device parameters is also obtained. The DBD plasma actuator is clearly shown to be very effective for controlling flow separation at a Reynolds number of around 10(5), and several times larger lift-to-drag ratio can be achieved at higher angles of attack after stall. For higher Reynolds numbers, separated flow is partially controlled. Flow analysis shows key features towards better control. DBD plasma actuators are a promising technology, which could reduce fuel consumption and contribute to a green environment by achieving high aerodynamic performance. The knowledge described above can be obtained only with high-end computers such as the supercomputer 'K'. PMID:25024414

  7. High-performance computing-based exploration of flow control with micro devices

    PubMed Central

    Fujii, Kozo

    2014-01-01

    The dielectric barrier discharge (DBD) plasma actuator that controls flow separation is one of the promising technologies to realize energy savings and noise reduction of fluid dynamic systems. However, the mechanism for controlling flow separation is not clearly defined, and this lack of knowledge prevents practical use of this technology. Therefore, large-scale computations for the study of the DBD plasma actuator have been conducted using the Japanese Petaflops supercomputer ‘K’ for three different Reynolds numbers. Numbers of new findings on the control of flow separation by the DBD plasma actuator have been obtained from the simulations, and some of them are presented in this study. Knowledge of suitable device parameters is also obtained. The DBD plasma actuator is clearly shown to be very effective for controlling flow separation at a Reynolds number of around 105, and several times larger lift-to-drag ratio can be achieved at higher angles of attack after stall. For higher Reynolds numbers, separated flow is partially controlled. Flow analysis shows key features towards better control. DBD plasma actuators are a promising technology, which could reduce fuel consumption and contribute to a green environment by achieving high aerodynamic performance. The knowledge described above can be obtained only with high-end computers such as the supercomputer ‘K’. PMID:25024414

  8. Damage-mitigating control of a reusable rocket engine for high performance and extended life

    NASA Technical Reports Server (NTRS)

    Ray, Asok; Dai, Xiaowen

    1995-01-01

    The goal of damage mitigating control in reusable rocket engines is to achieve high performance with increased durability of mechanical structures such that functional lives of the critical components are increased. The major benefit is an increase in structural durability with no significant loss of performance. This report investigates the feasibility of damage mitigating control of reusable rocket engines. Phenomenological models of creep and thermo-mechanical fatigue damage have been formulated in the state-variable setting such that these models can be combined with the plant model of a reusable rocket engine, such as the Space Shuttle Main Engine (SSME), for synthesizing an optimal control policy. Specifically, a creep damage model of the main thrust chamber wall is analytically derived based on the theories of sandwich beam and viscoplasticity. This model characterizes progressive bulging-out and incremental thinning of the coolant channel ligament leading to its eventual failure by tensile rupture. The objective is to generate a closed form solution of the wall thin-out phenomenon in real time where the ligament geometry is continuously updated to account for the resulting deformation. The results are in agreement with those obtained from the finite element analyses and experimental observation for both Oxygen Free High Conductivity (OFHC) copper and a copper-zerconium-silver alloy called NARloy-Z. Due to its computational efficiency, this damage model is suitable for on-line applications of life prediction and damage mitigating control, and also permits parametric studies for off-line synthesis of damage mitigating control systems. The results are presented to demonstrate the potential of life extension of reusable rocket engines via damage mitigating control. The control system has also been simulated on a testbed to observe how the damage at different critical points can be traded off without any significant loss of engine performance. The research work

  9. Multisensory systems integration for high-performance motor control in flies.

    PubMed

    Frye, Mark A

    2010-06-01

    Engineered tracking systems 'fuse' data from disparate sensor platforms, such as radar and video, to synthesize information that is more reliable than any single input. The mammalian brain registers visual and auditory inputs to directionally localize an interesting environmental feature. For a fly, sensory perception is challenged by the extreme performance demands of high speed flight. Yet even a fruit fly can robustly track a fragmented odor plume through varying visual environments, outperforming any human engineered robot. Flies integrate disparate modalities, such as vision and olfaction, which are neither related by spatiotemporal spectra nor processed by registered neural tissue maps. Thus, the fly is motivating new conceptual frameworks for how low-level multisensory circuits and functional algorithms produce high-performance motor control.

  10. Multisensory systems integration for high-performance motor control in flies.

    PubMed

    Frye, Mark A

    2010-06-01

    Engineered tracking systems 'fuse' data from disparate sensor platforms, such as radar and video, to synthesize information that is more reliable than any single input. The mammalian brain registers visual and auditory inputs to directionally localize an interesting environmental feature. For a fly, sensory perception is challenged by the extreme performance demands of high speed flight. Yet even a fruit fly can robustly track a fragmented odor plume through varying visual environments, outperforming any human engineered robot. Flies integrate disparate modalities, such as vision and olfaction, which are neither related by spatiotemporal spectra nor processed by registered neural tissue maps. Thus, the fly is motivating new conceptual frameworks for how low-level multisensory circuits and functional algorithms produce high-performance motor control. PMID:20202821

  11. Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

    NASA Technical Reports Server (NTRS)

    Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

    2012-01-01

    At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

  12. Performance of High-Speed PWM Control Chips at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard; Overton, Eric

    2001-01-01

    The operation of power electronic systems at cryogenic temperatures is anticipated in many NASA space missions such as planetary exploration and deep space probes. In addition to surviving the space hostile environment, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing development and launch costs. As part of the NASA Glenn Low Temperature Electronics Program, several commercial high-speed Pulse Width Modulation (PWM) chips have been characterized in terms of their performance as a function of temperature in the range of 25 to -196 C (liquid nitrogen). These chips ranged in their electrical characteristics, modes of control, packaging options, and applications. The experimental procedures along with the experimental data obtained on the investigated chips are presented and discussed.

  13. TiO2 microboxes with controlled internal porosity for high-performance lithium storage

    DOE PAGESBeta

    Gao, Xuehui; Li, Gaoran; Xu, Yangyang; Hong, Zhanglian; Liang, Chengdu; Lin, Zhan

    2015-10-02

    Titanium dioxide (TiO2) is considered a promising anode material for high-power lithium ion batteries (LIBs) because of its low cost, high thermal/chemical stability, and good safety performance without solid electrolyte interface formation. However, the poor electronic conductivity and low lithium ion diffusivity of TiO2 result in poor cyclability and lithium ion depletion at high current rates, which hinder them from practical applications. Herein we demonstrate that hierarchically structured TiO2 microboxes with controlled internal porosity can address the aforementioned problems for high-power, long-life LIB anodes. A self-templating method for the synthesis of mesoporous microboxes was developed through Na2EDTA-assisted ion exchange ofmore » CaTiO3 microcubes. The resulting TiO2 nanorods were organized into microboxes that resemble the microcube precursors. Furthermore, this nanostructured TiO2 material has superior lithium storage properties with a capacity of 187 mAh g-1 after 300 cycles at 1C and good rate capabilities up to 20C.« less

  14. TiO2 Microboxes with Controlled Internal Porosity for High-Performance Lithium Storage.

    PubMed

    Gao, Xuehui; Li, Gaoran; Xu, Yangyang; Hong, Zhanglian; Liang, Chengdu; Lin, Zhan

    2015-11-23

    Titanium dioxide (TiO2) is considered a promising anode material for high-power lithium ion batteries (LIBs) because of its low cost, high thermal/chemical stability, and good safety performance without solid electrolyte interface formation. However, the poor electronic conductivity and low lithium ion diffusivity of TiO2 result in poor cyclability and lithium ion depletion at high current rates, which hinder them from practical applications. Herein we demonstrate that hierarchically structured TiO2 microboxes with controlled internal porosity can address the aforementioned problems for high-power, long-life LIB anodes. A self-templating method for the synthesis of mesoporous microboxes was developed through Na2 EDTA-assisted ion exchange of CaTiO3 microcubes. The resulting TiO2 nanorods were organized into microboxes that resemble the microcube precursors. This nanostructured TiO2 material has superior lithium storage properties with a capacity of 187 mAh g(-1) after 300 cycles at 1 C and good rate capabilities up to 20 C.

  15. Low-Noise High-Performance Current Controllers for Quantum Cascade Lasers

    SciTech Connect

    Taubman, Matthew S.

    2011-06-01

    Quantum cascade lasers have ushered in a new era of enhanced capability for chemical sensing. The higher current and voltage demands of these devices over their laser diode counterparts has also ushered in the demand for more capable drive electronics. The current-sensitivity and high frequency response of these devices has continued the desire for low noise, stability and agility enjoyed by the laser diode community for many years. This article addresses the issue of maintaining these characteristics at the currents and voltages required, and presents example performance of current controllers developed by the author at Pacific Northwest National Laboratory, achieving output currents up to two amperes and compliance voltages of 15 volts, with noise levels close to the Johnson noise of the internal resistors, typically a few nA/rt-Hz. Full current depth rapid modulation up to 100 kHz is also demonstrated.

  16. Low-noise high-performance current controllers for quantum cascade lasers.

    PubMed

    Taubman, Matthew S

    2011-06-01

    Quantum cascade lasers have ushered in a new era of enhanced capability for chemical sensing. The higher current and voltage demands of these devices over their laser diode counterparts have also ushered in the demand for more capable drive electronics. The current-sensitivity and high frequency response of these devices have continued the desire for low noise, stability, and agility enjoyed by the laser diode community for many years. This article addresses the issue of maintaining these characteristics at the currents and voltages required, and presents example performance of current controllers developed by the author at Pacific Northwest National Laboratory, achieving output currents up to 2 A and compliance voltages of 15 V, with noise levels close to the Johnson noise of the internal resistors, typically a few nA/√Hz. Rapid full-depth current modulation up to 100 kHz is also demonstrated.

  17. Materials for high-energy laser windows: how thermal lensing and thermal stresses control the performance

    NASA Astrophysics Data System (ADS)

    Klein, Claude A.

    2007-09-01

    The engineering of high-energy lasers (HELs) for applications such as the airborne laser (ABL) system requires optical windows capable of handling megajoule beam energies. The selection of a suitable window material involves considerations relating to thermal lensing, i.e., the beam distortion caused by thermally induced phase-aberrations, in addition to issues arising from the thermal stresses generated by beam-induced temperature gradients. In this paper we document analytical methods for evaluating the impact of both beam-induced optical distortions and beam-induced mechanical stresses, which may allow the designer to properly assess the performance of window-material candidates. Specifically, thermal lensing in conjunction with planar stresses control the allowable beam fluence, whereas the two axial-stress related failure modes (thermal-shock induced fracture and yielding in compression) control the allowable beam intensity. We illustrate these considerations in the light of an evaluation of the performance of three window-material candidates for operation at the 1.315-μm wavelength. Currently, fused Si02 is the window material of choice for contemplated HELs operating in the near infrared; it is, however, vulnerable to optical distortion, which renders this material unsuitable for applications that require transmitting large beam fluences. On assuming that stress-birefringence is of no concern, oxyfluoride glass outperforms Si02, but evidence of a poor thermal conductivity degrades this material's ability to transmit high-intensity beams. Fusion-cast CaF2 emerges as the most promising "compromise" solution in the sense that this material combines superior optical features with acceptable thermomechanical properties; in effect, CaF2 windows easily meet requirements as formulated for the first-generation ABL system.

  18. Advanced use of high-performance liquid chromatography for synthesis of controlled metal clusters

    NASA Astrophysics Data System (ADS)

    Niihori, Yoshiki; Matsuzaki, Miku; Uchida, Chihiro; Negishi, Yuichi

    2014-06-01

    Because the synthesis of metal clusters with multiple ligand types results in a distribution of ligands, high-resolution separation of each unique cluster from the mixture is required for precise control of the ligand composition. Reverse-phase high-performance liquid chromatography combined with appropriate transitioning of the mobile phase composition is an extremely effective means of separating ligand combinations when working with metal clusters protected by two different types of thiolates. We report herein advanced use of this method. The studies involving Au24Pd(SR1)18-x(SR2)x and Au24Pd(SR1)18-x(SeR2)x (SR1, SR2 = thiolate, SeR2 = selenolate) revealed the following. (1) In general, an increase in the difference between the polarities of the functional groups incorporated in the two types of ligands improves the separation resolution. A suitable ligand combination for separation can be predicted from the retention times of Au24Pd(SR1)18 and Au24Pd(SR2)18, which cause the terminal peaks in a series of peaks. (2) The use of a step-gradient program during the mobile phase substitution results in improved resolution compared to that achievable with the linear gradients applied in prior work. (3) This technique is also useful for the evaluation of the chemical compositions of metal clusters protected by two different types of ligands with similar molecular weights. These findings will provide clear design guidelines for the functionalization of metal clusters via control of the ligand composition, and will also improve our understanding of the high-resolution isolation of metal clusters.Because the synthesis of metal clusters with multiple ligand types results in a distribution of ligands, high-resolution separation of each unique cluster from the mixture is required for precise control of the ligand composition. Reverse-phase high-performance liquid chromatography combined with appropriate transitioning of the mobile phase composition is an extremely effective

  19. CF6 Jet Engine Performance Improvement: High Pressure Turbine Active Clearance Control

    NASA Technical Reports Server (NTRS)

    Rich, S. E.; Fasching, W. A.

    1982-01-01

    An active clearance control system was developed which reduces fuel consumption and performance degradation. This system utilizes compressor discharge air during takeoff and fan discharge air during cruise to impinge on the shroud structure to improve the thermal response. The system was evaluated in component and engine tests. The test results demonstrated a performance improvement of 0.7 percent in cruise SFC.

  20. Sentinel-3 Mission Performance Center: paving the way of high-quality controlled data

    NASA Astrophysics Data System (ADS)

    Bruniquel, Jerome; Féménias, Pierre; Goryl, Philippe; Bonekamp, Hans

    2015-04-01

    As part of the Sentinel-3 mission and in order to ensure the highest quality of products, ESA and EUMETSAT set up the Sentinel-3 Mission Performance Centre (S-3 MPC). This facility is part of the Payload Data Ground Segment (PDGS) and aims at controlling the quality of all generated products, from L0 to L2. The S-3 MPC is composed of a Coordinating Centre (CC), where the core infrastructure is hosted, which is in charge of the main routine activities (especially the quality control of data) and the overall service management. Expert Support Laboratories (ESLs) are involved in calibration and validation activities and provide specific assessment of the products (e.g., analysis of trends, ad hoc analysis of anomalies, etc.). The S-3 MPC interacts with the Processing Archiving Centers (PACs) and the marine centre at EUMETSAT. The S-3 MPC service contract is currently carried out by 23-partners consortium led by ACRI-ST, France. The S-3 MPC contract was kick-offed in September 2014 with a first set-up phase of 12 months. After the launch of S3-A (planned before end of 2015), the S-3 MPC will start its second phase to support commissioning activities. Then a routine operation phase of up to 5 years will begin, including the commissioning activities related to S3-B. The main S-3 MPC activities are: - Calibration: to update on-board and on-ground configuration data in order to meet product quality requirements. - Validation: to assess, by independent means with respect to the methods and tools used for calibration, the quality of the generated data products. Validation functions provide feedback to calibration and data processors corrective and perfective maintenance activities. - Verification: to confirm that the specified requirements on a system have been satisfied. - Quality Control: to routinely monitor the status of the sensor and to check if the derived products (Level 0, Level 1 and Level 2) meet the quality requirements along mission lifetime. - Algorithm

  1. An Electronic Workshop on the Performance Seeking Control and Propulsion Controlled Aircraft Results of the F-15 Highly Integrated Digital Electronic Control Flight Research Program

    NASA Technical Reports Server (NTRS)

    Powers, Sheryll Goecke (Compiler)

    1995-01-01

    Flight research for the F-15 HIDEC (Highly Integrated Digital Electronic Control) program was completed at NASA Dryden Flight Research Center in the fall of 1993. The flight research conducted during the last two years of the HIDEC program included two principal experiments: (1) performance seeking control (PSC), an adaptive, real-time, on-board optimization of engine, inlet, and horizontal tail position on the F-15; and (2) propulsion controlled aircraft (PCA), an augmented flight control system developed for landings as well as up-and-away flight that used only engine thrust (flight controls locked) for flight control. In September 1994, the background details and results of the PSC and PCA experiments were presented in an electronic workshop, accessible through the Dryden World Wide Web (http://www.dfrc.nasa.gov/dryden.html) and as a compact disk.

  2. Real-Time Adaptive Control Allocation Applied to a High Performance Aircraft

    NASA Technical Reports Server (NTRS)

    Davidson, John B.; Lallman, Frederick J.; Bundick, W. Thomas

    2001-01-01

    Abstract This paper presents the development and application of one approach to the control of aircraft with large numbers of control effectors. This approach, referred to as real-time adaptive control allocation, combines a nonlinear method for control allocation with actuator failure detection and isolation. The control allocator maps moment (or angular acceleration) commands into physical control effector commands as functions of individual control effectiveness and availability. The actuator failure detection and isolation algorithm is a model-based approach that uses models of the actuators to predict actuator behavior and an adaptive decision threshold to achieve acceptable false alarm/missed detection rates. This integrated approach provides control reconfiguration when an aircraft is subjected to actuator failure, thereby improving maneuverability and survivability of the degraded aircraft. This method is demonstrated on a next generation military aircraft Lockheed-Martin Innovative Control Effector) simulation that has been modified to include a novel nonlinear fluid flow control control effector based on passive porosity. Desktop and real-time piloted simulation results demonstrate the performance of this integrated adaptive control allocation approach.

  3. Direct selective laser sintering of high performance metals: Machine design, process development and process control

    NASA Astrophysics Data System (ADS)

    Das, Suman

    1998-11-01

    This dissertation describes the development of an advanced manufacturing technology known as Direct Selective Laser Sintering (Direct SLS). Direct SLS is a laser based rapid manufacturing technology that enables production of functional, fully dense, metal and cermet components via the direct, layerwise consolidation of constituent powders. Specifically, this dissertation focuses on a new, hybrid net shape manufacturing technique known as Selective Laser Sintering/Hot Isostatic Pressing (SLS/HIP). The objective of research presented in this dissertation was to establish the fundamental machine technology and processing science to enable direct SLS fabrication of metal components composed of high performance, high temperature metals and alloys. Several processing requirements differentiate direct SLS of metals from SLS of polymers or polymer coated powders. Perhaps the most important distinguishing characteristic is the regime of high temperatures involved in direct SLS of metals. Biasing the temperature of the feedstock powder via radiant preheat prior to and during SLS processing was shown to be beneficial. Preheating the powder significantly influenced the flow and wetting characteristics of the melt. During this work, it was conclusively established that powder cleanliness is of paramount importance for successful layerwise consolidation of metal powders by direct SLS. Sequential trials were conducted to establish optimal bake-out and degas cycles under high vacuum. These cycles agreed well with established practices in the powder metallurgy industry. A study of some of the important transport mechanisms in direct SLS of metals was undertaken to obtain a fundamental understanding of the underlying process physics. This study not only provides an explanation of phenomena observed during SLS processing of a variety of metallic materials but also helps in developing selection schemes for those materials that are most amenable to direct SLS processing. The

  4. Development of high-performance liquid chromatographic for quality and authenticity control of Chinese propolis.

    PubMed

    Cui-ping, Zhang; Shuai, Huang; Wen-ting, Wei; Shun, Ping; Xiao-ge, Shen; Ya-jing, Li; Fu-liang, Hu

    2014-07-01

    A RP-high-performance liquid chromatography (HPLC) method was developed for quality control of Chinese propolis by simultaneous analysis of 12 flavonoids and 8 phenolic acids. The results showed that vanillic acid, rutin, myricetin, and luteolin were not detected in all of the analyzed propolis and poplar tree gum samples. The caffeic acid, ferulic acid and p-coumaric acid were not detected in poplar tree gum but were detected in propolis, which suggest that they are practical indexes of distinguishing propolis from poplar tree gum. The flavonoid profiles of poplar tree gum were found to be similar to those of propolis, which are dominated by pinobanksin, pinocembrin, 3-O-acetylpinobanksin, chrysin, and galangin. Therefore, the proposed method could be applied to exclude poplar tree gum from propolis with cafferic acid, ferulic acid, and p-coumaric acid as qualitative markers, and distinguish poplar source resin from other illegal substances, and evaluate the quality grading of poplar-type propolis with pinobanksin, pinocembrin, 3-O-acetylpinobanksin, chrysin, and galangin as qualitative and quantitative markers.

  5. Modeling and control of actuators for high performance structural dynamic testing

    NASA Astrophysics Data System (ADS)

    Gao, X.; Dyke, S. J.

    2014-05-01

    Most research in the structural engineering field uses either a simplified data-based model or a physics-based model to describe the dynamic behavior of servo-hydraulic actuators. In either way, the nominal model is typically used for modeling, analysis and control design. However, little effort has been directed to model uncertainties that are inherently associated with any physical system. A robust modeling approach is proposed in this study that can characterize both parametric and non-parametric uncertainties. The combination of this uncertainty with the nominal model provides a powerful tool to analyze the system performance and stability properties. Several control techniques are evaluated experimentally, and an H∞ robust control design is demonstrated to achieve the best performance as well as good robustness.

  6. High performance, accelerometer-based control of the Mini-MAST structure at Langley Research Center

    NASA Technical Reports Server (NTRS)

    Collins, Emmanuel G., Jr.; King, James A.; Phillips, Douglas J.; Hyland, David C.

    1991-01-01

    Many large space system concepts will require active vibration control to satisfy critical performance requirements such as line of sight pointing accuracy and constraints on rms surface roughness. In order for these concepts to become operational, it is imperative that the benefits of active vibration control be shown to be practical in ground based experiments. The results of an experiment shows the successful application of the Maximum Entropy/Optimal Projection control design methodology to active vibration control for a flexible structure. The testbed is the Mini-Mast structure at NASA-Langley and has features dynamically traceable to future space systems. To maximize traceability to real flight systems, the controllers were designed and implemented using sensors (four accelerometers and one rate gyro) that are actually mounted to the structure. Ground mounted displacement sensors that could greatly ease the control design task were available but were used only for performance evaluation. The use of the accelerometers increased the potential of destabilizing the system due to spillover effects and motivated the use of precompensation strategy to achieve sufficient compensator roll-off.

  7. High performance, accelerometer-based control of the Mini-MAST structure

    NASA Technical Reports Server (NTRS)

    Collins, Emmanuel G., Jr.; King, James A.; Phillips, Douglas J.; Hyland, David C.

    1992-01-01

    Many large space system concepts will require active vibration control to satisfy critical performance requirements such as line of sight pointing accuracy and constraints on rms surface roughness. In order for these concepts to become operational, it is imperative that the benefits of active vibration control be shown to be practical in ground based experiments. The results of an experiment shows the successful application of the Maximum Entropy/Optical Projection control design methodology to active vibration control for a flexible structure. The testbed is the Mini-Mast structure at NASA-Langley and has features dynamically traceable to future space systems. To maximize traceability to real flight systems, the controllers were designed and implemented using sensors (four accelerometers and one rate gyro) that are actually mounted to the structure. Ground mounted displacement sensors that could greatly ease the control design task were available but were used only for performance evaluation. The use of the accelerometers increased the potential of destabilizing the system due to spillover effects and motivated the use of precompensation strategy to achieve sufficient compensator roll-off.

  8. Constructing a LabVIEW-Controlled High-Performance Liquid Chromatography (HPLC) System: An Undergraduate Instrumental Methods Exercise

    ERIC Educational Resources Information Center

    Smith, Eugene T.; Hill, Marc

    2011-01-01

    In this laboratory exercise, students develop a LabVIEW-controlled high-performance liquid chromatography system utilizing a data acquisition device, two pumps, a detector, and fraction collector. The programming experience involves a variety of methods for interface communication, including serial control, analog-to-digital conversion, and…

  9. Performance, Performance System, and High Performance System

    ERIC Educational Resources Information Center

    Jang, Hwan Young

    2009-01-01

    This article proposes needed transitions in the field of human performance technology. The following three transitions are discussed: transitioning from training to performance, transitioning from performance to performance system, and transitioning from learning organization to high performance system. A proposed framework that comprises…

  10. A robust and high-performance queue management controller for large round trip time networks

    NASA Astrophysics Data System (ADS)

    Khoshnevisan, Ladan; Salmasi, Farzad R.

    2016-05-01

    Congestion management for transmission control protocol is of utmost importance to prevent packet loss within a network. This necessitates strategies for active queue management. The most applied active queue management strategies have their inherent disadvantages which lead to suboptimal performance and even instability in the case of large round trip time and/or external disturbance. This paper presents an internal model control robust queue management scheme with two degrees of freedom in order to restrict the undesired effects of large and small round trip time and parameter variations in the queue management. Conventional approaches such as proportional integral and random early detection procedures lead to unstable behaviour due to large delay. Moreover, internal model control-Smith scheme suffers from large oscillations due to the large round trip time. On the other hand, other schemes such as internal model control-proportional integral and derivative show excessive sluggish performance for small round trip time values. To overcome these shortcomings, we introduce a system entailing two individual controllers for queue management and disturbance rejection, simultaneously. Simulation results based on Matlab/Simulink and also Network Simulator 2 (NS2) demonstrate the effectiveness of the procedure and verify the analytical approach.

  11. Controlling the Interface Areas of Organic/Inorganic Semiconductor Heterojunction Nanowires for High-Performance Diodes.

    PubMed

    Xue, Zheng; Yang, Hui; Gao, Juan; Li, Jiaofu; Chen, Yanhuan; Jia, Zhiyu; Li, Yongjun; Liu, Huibiao; Yang, Wensheng; Li, Yuliang; Li, Dan

    2016-08-24

    A new method of in situ electrically induced self-assembly technology combined with electrochemical deposition has been developed for the controllable preparation of organic/inorganic core/shell semiconductor heterojunction nanowire arrays. The size of the interface of the heterojunction nanowire can be tuned by the growing parameter. The heterojunction nanowires of graphdiyne/CuS with core/shell structure showed the strong dependence of rectification ratio and perfect diode performance on the size of the interface. It will be a new way for controlling the structures and properties of one-dimensional heterojunction nanomaterials. PMID:27472226

  12. Mission Control Operations: Employing a New High Performance Design for Communications Links Supporting Exploration Programs

    NASA Technical Reports Server (NTRS)

    Jackson, Dan E., Jr.

    2015-01-01

    The planetary exploration programs demand a totally new examination of data multiplexing, digital communications protocols and data transmission principles for both ground and spacecraft operations. Highly adaptive communications devices on-board and on the ground must provide the greatest possible transmitted data density between deployed crew personnel, spacecraft and ground control teams. Regarding these requirements, this proposal borrows from research into quantum mechanical computing by applying the concept of a qubit, a single bit that represents 16 states, to radio frequency (RF) communications link design for exploration programs. This concept of placing multiple character values into a single data bit can easily make the evolutionary steps needed to meet exploration mission demands. To move the qubit from the quantum mechanical research laboratory into long distance RF data transmission, this proposal utilizes polarization modulation of the RF carrier signal to represent numbers from zero to fifteen. It introduces the concept of a binary-to-hexadecimal converter that quickly chops any data stream into 16-bit words and connects variously polarized feedhorns to a single-frequency radio transmitter. Further, the concept relies on development of a receiver that uses low-noise amplifiers and an antenna array to quickly assess carrier polarity and perform hexadecimal to binary conversion. Early testbed experiments using the International Space Station (ISS) as an operations laboratory can be implemented to provide the most cost-effective return for research investment. The improvement in signal-to-noise ratio while supporting greater baseband data rates that could be achieved through this concept justifies its consideration for long-distance exploration programs.

  13. High Performance FORTRAN

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush

    1994-01-01

    High performance FORTRAN is a set of extensions for FORTRAN 90 designed to allow specification of data parallel algorithms. The programmer annotates the program with distribution directives to specify the desired layout of data. The underlying programming model provides a global name space and a single thread of control. Explicitly parallel constructs allow the expression of fairly controlled forms of parallelism in particular data parallelism. Thus the code is specified in a high level portable manner with no explicit tasking or communication statements. The goal is to allow architecture specific compilers to generate efficient code for a wide variety of architectures including SIMD, MIMD shared and distributed memory machines.

  14. Control of interfacial layers for high-performance porous Si lithium-ion battery anode.

    PubMed

    Park, Hyungmin; Lee, Sungjun; Yoo, Seungmin; Shin, Myoungsoo; Kim, Jieun; Chun, Myungjin; Choi, Nam-Soon; Park, Soojin

    2014-09-24

    We demonstrate a facile synthesis of micrometer-sized porous Si particles via copper-assisted chemical etching process. Subsequently, metal and/or metal silicide layers are introduced on the surface of porous Si particles using a simple chemical reduction process. Macroporous Si and metal/metal silicide-coated Si electrodes exhibit a high initial Coulombic efficiency of ∼90%. Reversible capacity of carbon-coated porous Si gradually decays after 80 cycles, while metal/metal silicide-coated porous Si electrodes show significantly improved cycling performance even after 100 cycles with a reversible capacity of >1500 mAh g(-1). We confirm that a stable solid-electrolyte interface layer is formed on metal/metal silicide-coated porous Si electrodes during cycling, leading to a highly stable cycling performance. PMID:25153926

  15. Control of interfacial layers for high-performance porous Si lithium-ion battery anode.

    PubMed

    Park, Hyungmin; Lee, Sungjun; Yoo, Seungmin; Shin, Myoungsoo; Kim, Jieun; Chun, Myungjin; Choi, Nam-Soon; Park, Soojin

    2014-09-24

    We demonstrate a facile synthesis of micrometer-sized porous Si particles via copper-assisted chemical etching process. Subsequently, metal and/or metal silicide layers are introduced on the surface of porous Si particles using a simple chemical reduction process. Macroporous Si and metal/metal silicide-coated Si electrodes exhibit a high initial Coulombic efficiency of ∼90%. Reversible capacity of carbon-coated porous Si gradually decays after 80 cycles, while metal/metal silicide-coated porous Si electrodes show significantly improved cycling performance even after 100 cycles with a reversible capacity of >1500 mAh g(-1). We confirm that a stable solid-electrolyte interface layer is formed on metal/metal silicide-coated porous Si electrodes during cycling, leading to a highly stable cycling performance.

  16. Whisker: a client-server high-performance multimedia research control system.

    PubMed

    Cardinal, Rudolf N; Aitken, Michael R F

    2010-11-01

    We describe an original client-server approach to behavioral research control and the Whisker system, a specific implementation of this design. The server process controls several types of hardware, including digital input/output devices, multiple graphical monitors and touchscreens, keyboards, mice, and sound cards. It provides a way to access this hardware for client programs, communicating with them via a simple text-based network protocol based on the standard Internet protocol. Clients to implement behavioral tasks may be written in any network-capable programming language. Applications to date have been in experimental psychology and behavioral and cognitive neuroscience, using rodents, humans, nonhuman primates, dogs, pigs, and birds. This system is flexible and reliable, although there are potential disadvantages in terms of complexity. Its design, features, and performance are described. PMID:21139173

  17. Nanoscale interface control for high-performance Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Oh, Yuhong; Nam, Seunghoon; Wi, Sungun; Hong, Saeromi; Park, Byungwoo

    2012-04-01

    Li-ion batteries have attracted great interest for the past decades, and now are one of the most important power sources for portable electronic devices, store electricity, hybrid electric vehicles (HEV), etc. However, Li-ion-battery technologies still have several problems related to the electrochemical performance (cycle-life performance and power density) or safety of the active electrode materials. There have been numerous breakthrough challenges to overcome these problems by extensive research. Among the various methods to improve the battery's electrochemical properties, nanoscale coating on active materials and control of the nanostructured morphology were proven as effective approaches over the last decade. In this review paper, enhanced electrochemical properties of the cathode and anode materials via nanoscale interface modification and the respective enhancing mechanisms will be discussed.

  18. Damage-mitigating control of space propulsion systems for high performance and extended life

    NASA Technical Reports Server (NTRS)

    Ray, Asok; Wu, Min-Kuang; Dai, Xiaowen; Carpino, Marc; Lorenzo, Carl F.

    1993-01-01

    Calculations are presented showing that a substantial improvement in service life of a reusable rocket engine can be achieved by an insignificant reduction in the system dynamic performance. The paper introduces the concept of damage mitigation and formulates a continuous-time model of fatigue damage dynamics. For control of complex mechanical systems, damage prediction and damage mitigation are carried out based on the available sensory and operational information such that the plant can be inexpensively maintained and safely and efficiently steered under diverse operating conditions. The results of simulation experiments are presented for transient operations of a reusable rocket engine.

  19. The sun-tracking control of solar collectors using high-performance step motors

    NASA Technical Reports Server (NTRS)

    Hughes, R. O.

    1977-01-01

    Sun-tracking solar energy-focusing devices involving a central receiver, thermionic conversion, or a distributed solar thermal collector system are described. The Perkins solar collector uses a fixed focal point about which an 18 m-diameter parabolic dish moves on tracks. The elevation axis also moves on a circular track. A microprocessor manipulates sun sensor information and sun ephemeris data to ensure correct placement. Stepper motors are digital devices which provide direct interface with digital electronics and a wide dynamic range, and could easily be associated with the microprocessors. Design philosophy, performance criteria, wind load analysis, and control system requirements are also discussed.

  20. Construction of High-Performance, Low-Cost Photoelectrodes with Controlled Polycrystalline Architectures

    SciTech Connect

    Kyoung-Shin Choi

    2013-06-30

    The major goal of our research was to gain the ability in electrochemical synthesis to precisely control compositions and morphologies of various oxide-based polycrystalline photoelectrodes in order to establish the composition-morphology-photoelectrochemical property relationships while discovering highly efficient photoelectrode systems for use in solar energy conversion. Major achievements include: development of porous n-type BiVO{sub 4} photoanode for efficient and stable solar water oxidation; development of p-type CuFeO{sub 2} photocathode for solar hydrogen production; and junction studies on electrochemically fabricated p-n Cu{sub 2}O homojunction solar cells for efficiency enhancement.

  1. Runtime Performance and Virtual Network Control Alternatives in VM-Based High-Fidelity Network Simulations

    SciTech Connect

    Yoginath, Srikanth B; Perumalla, Kalyan S; Henz, Brian J

    2012-01-01

    In prior work (Yoginath and Perumalla, 2011; Yoginath, Perumalla and Henz, 2012), the motivation, challenges and issues were articulated in favor of virtual time ordering of Virtual Machines (VMs) in network simulations hosted on multi-core machines. Two major components in the overall virtualization challenge are (1) virtual timeline establishment and scheduling of VMs, and (2) virtualization of inter-VM communication. Here, we extend prior work by presenting scaling results for the first component, with experiment results on up to 128 VMs scheduled in virtual time order on a single 12-core host. We also explore the solution space of design alternatives for the second component, and present performance results from a multi-threaded, multi-queue implementation of inter-VM network control for synchronized execution with VM scheduling, incorporated in our NetWarp simulation system.

  2. High Contrast Vacuum Nuller Testbed (VNT) Contrast, Performance and Null Control

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.

    2012-01-01

    Herein we report on our Visible Nulling Coronagraph high-contrast result of 109 contrast averaged over a focal planeregion extending from 14 D with the Vacuum Nuller Testbed (VNT) in a vibration isolated vacuum chamber. TheVNC is a hybrid interferometriccoronagraphic approach for exoplanet science. It operates with high Lyot stopefficiency for filled, segmented and sparse or diluted-aperture telescopes, thereby spanning the range of potential futureNASA flight telescopes. NASAGoddard Space Flight Center (GSFC) has a well-established effort to develop the VNCand its technologies, and has developed an incremental sequence of VNC testbeds to advance this approach and itsenabling technologies. These testbeds have enabled advancement of high-contrast, visible light, nulling interferometry tounprecedented levels. The VNC is based on a modified Mach-Zehnder nulling interferometer, with a W configurationto accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters.We give an overview of the VNT and discuss the high-contrast laboratory results, the optical configuration, criticaltechnologies and null sensing and control.

  3. Carbohydrate supplementation and exercise performance at high altitude: a randomized controlled trial.

    PubMed

    Oliver, Samuel J; Golja, Petra; Macdonald, Jamie H

    2012-03-01

    Acute carbohydrate supplementation decreases effort perception and increases endurance exercise capacity at sea level. It also improves laboratory-based endurance performance at altitude. However, the effect of chronic carbohydrate supplementation at altitude, when acclimatization may attenuate carbohydrate effects, achieved doses are lower and metabolic effects may be different, is unknown and was therefore focused on in the present study. Forty-one members of a 22-day high altitude expedition were randomized in a double-blind design to receive either placebo or carbohydrate supplementation. Diet was manipulated with commercially available energy drinks consumed ad libitum throughout the expedition. Participants performed a mountaineering time trial at 5192 m, completed submaximal incremental exercise step tests to assess cardiovascular parameters before, during, and after the expedition, and recorded spontaneous physical activity by accelerometer on rest days. Compared to placebo, compliant individuals of the carbohydrate-supplemented group received daily an additional 3.5±1.4 g carbohydrate·kg body mass(-1). Compliant individuals of the carbohydrate supplemented group reported 18% lower ratings of perceived exertion during the time trial at altitude, and completed it 17% faster than the placebo group (both p<0.05 by t-test). However, cardiovascular parameters obtained during submaximal exercise and spontaneous physical activity on rest days were similar between the two groups (all p>0.05 by analysis of variance). This study utilized testing protocols of specific relevance to high altitude sojourners, including the highest mountaineering time trial completed to date at altitude. Chronic carbohydrate supplementation reduced ratings of perceived exertion and improved physical performance, especially during prolonged and higher intensity exercise tasks. PMID:22429229

  4. Controllable film densification and interface flatness for high-performance amorphous indium oxide based thin film transistors

    SciTech Connect

    Ou-Yang, Wei E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Mitoma, Nobuhiko; Kizu, Takio; Gao, Xu; Lin, Meng-Fang; Tsukagoshi, Kazuhito E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Nabatame, Toshihide

    2014-10-20

    To avoid the problem of air sensitive and wet-etched Zn and/or Ga contained amorphous oxide transistors, we propose an alternative amorphous semiconductor of indium silicon tungsten oxide as the channel material for thin film transistors. In this study, we employ the material to reveal the relation between the active thin film and the transistor performance with aid of x-ray reflectivity study. By adjusting the pre-annealing temperature, we find that the film densification and interface flatness between the film and gate insulator are crucial for achieving controllable high-performance transistors. The material and findings in the study are believed helpful for realizing controllable high-performance stable transistors.

  5. High-performance reverse osmosis CNT/polyamide nanocomposite membrane by controlled interfacial interactions.

    PubMed

    Kim, Hee Joong; Choi, Kwonyong; Baek, Youngbin; Kim, Dong-Gyun; Shim, Jimin; Yoon, Jeyong; Lee, Jong-Chan

    2014-02-26

    Polyamide reverse osmosis (RO) membranes with carbon nanotubes (CNTs) are prepared by interfacial polymerization using trimesoyl chloride (TMC) solutions in n-hexane and aqueous solutions of m-phenylenediamine (MPD) containing functionalized CNTs. The functionalized CNTs are prepared by the reactions of pristine CNTs with acid mixture (sulfuric acid and nitric acid of 3:1 volume ratio) by varying amounts of acid, reaction temperature, and reaction time. CNTs prepared by an optimized reaction condition are found to be well-dispersed in the polyamide layer, which is confirmed from atomic force microscopy, scanning electron microscopy, and Raman spectroscopy studies. The polyamide RO membranes containing well-dispersed CNTs exhibit larger water flux values than polyamide membrane prepared without any CNTs, although the salt rejection values of these membranes are close. Furthermore, the durability and chemical resistance against NaCl solutions of the membranes containing CNTs are found to be improved compared with those of the membrane without CNTs. The high membrane performance (high water flux and salt rejection) and the improved stability of the polyamide membranes containing CNTs are ascribed to the hydrophobic nanochannels of CNTs and well-dispersed states in the polyamide layers formed through the interactions between CNTs and polyamide in the active layers.

  6. Tail buffet alleviation of high performance twin tail aircraft using offset piezoceramic stack actuators and acceleration feedback control

    NASA Astrophysics Data System (ADS)

    Bayon de Noyer, Maxime P.

    In High Performance Twin-Tail Aircraft (HPTTA), tail buffet occurs during high angles of attack maneuvers. At high angles of attack, flow separates and vortices are convected by the geometry of the wing-fuselage interface toward the vertical tails. This phenomenon, along with the aeroelastic coupling of the tail structural assembly, results in vibrations that can shorten the fatigue life of the empennage assembly and limit the flight envelope due to the large amplitude of the fin vibrations. The main goal of this research was to develop an active buffet alleviation system for HPTTA using Offset Piezoceramic Stack Actuators (OPSA) in combination with Acceleration Feedback Control (AFC) theory. In order to complete this task, the research work was divided into three main areas. First, two new methods for the design of non-collocated AFC controller parameters were developed for pure active damping applications and for quadratic performance criterion minimization. Second, a new type of moment inducing actuator based on piezoceramic stacks, the OPSA, was developed to provide high control authority while satisfying high reliability and maintainability requirements. A modal model of the OPSA acting on a benchmark structure was developed to create a low frequency approximation of the actuator and to optimize its offset distance and its placement. Third, because of the non-availability of reliable models for the controlled structure and the buffet-induced loads, a control system design method, based solely on the use of experimental data, was developed. Finally, two sets of experiments were conducted to show the feasibility of controlling buffet-induced vibrations during high angle of attack operations of a HPTTA. The first experiment validated both the effectiveness and the robustness of the active buffet alleviation system on an aeroelastically scaled model in wind tunnel tests. The second experiment showed that the combination of OPSA and AFC could suppress vibrations in

  7. Controlling Capital Costs in High Performance Office Buildings: A Review of Best Practices for Overcoming Cost Barriers

    SciTech Connect

    Pless, S.; Torcellini, P.

    2012-05-01

    This paper presents a set of 15 best practices for owners, designers, and construction teams of office buildings to reach high performance goals for energy efficiency, while maintaining a competitive budget. They are based on the recent experiences of the owner and design/build team for the Research Support Facility (RSF) on National Renewable Energy Facility's campus in Golden, CO, which show that achieving this outcome requires each key integrated team member to understand their opportunities to control capital costs.

  8. Process for controlling morphology and improving thermal mechanical performance of high performance interpenetrating and semiinterpenetrating polymer networks

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor); Hansen, Marion G. (Inventor)

    1998-01-01

    In the process of the present invention, a non-polar, aprotic solvent is removed from an oligomer/polymer solution by freeze-drying in order to produce IPNs and semi-IPNs. By thermally quenching the solution to a solid in a short length of time, the size of the minor constituent-rich regions is greatly reduced as they are excluded along with the major constituent from the regions of crystallizing solvent. The use of this process sequence of controlling phase morphology provides IPNs and semi-IPNs with improved fracture toughness, microcracking resistance, and other physical-mechanical properties as compared to IPNs and semi-IPNs formed when the solvent is evaporated rather than sublimed.

  9. Process for controlling morphology and improving thermal-mechanical performance of high performance interpenetrating and semi-interpenetrating polymer networks

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor); Hansen, Marion G. (Inventor)

    1997-01-01

    In the process of the present invention, a non-polar, aprotic solvent is removed from an oligomer/polymer solution by freeze-drying in order to produce IPNs and semi-IPNs. By thermally quenching the solution to a solid in a short length of time, the size of the minor constituent-rich regions is greatly reduced as they are excluded along with the major constituent from the regions of crystallizing solvent. The use of this process sequence of controlling phase morphology provides IPNs and semi-IPNs with improved fracture toughness, microcracking resistance, and other physical-mechanical properties as compared to IPNs and semi-IPNs formed when the solvent is evaporated rather than sublimed.

  10. High Performance Operation Control for Heat Driven Heat Pump System using Metal Hydride

    NASA Astrophysics Data System (ADS)

    Okamoto, Hideyuki; Masuda, Masao; Kozawa, Yoshiyuki

    lt is recognized that COP of heat driven heat pump system using metal hydride is 0.3-0.4 in general. In order to rise COP, we have proposed two kinds of specific operation control; the control of cycle change time according to cold heat load and the control of cooling water temperature according to outside air wet-bulb temperature. The characteristics of the heat pump system using metal hydride have grasped by various experiments and simulations. The validity of the simulation model has been confirmed by comparing with experimental results. As results of the simulations programmed for the actual operation control month by month, yearly COP has risen till 0.5-0.6 for practical scale air-conditioning system without regard for the building use. By the operation control hour by hour, yearly COP has risen till 0.6-0.65. Moreover, in the office building case added 40% sensible heat recovery, yearly COP has risen more than 0.8.

  11. A high-performance network for a distributed-control system

    NASA Astrophysics Data System (ADS)

    Cuttone, G.; Aghion, F.; Giove, D.

    1989-04-01

    Local area networks play a central rule in modern distributed-control systems for accelerators. For a superconducting cyclotron under construction at the University of Milan, an optical Ethernet network has been implemented for the interconnection of multicomputer-based stations. Controller boards, with VLSI protocol chips, have been used. The higher levels of the ISO OSI model have been implemented to suit real-time control requirements. The experimental setup for measuring the data throughput between stations will be described. The effect of memory-to-memory data transfer with respect to the packet size has been studied for packets ranging from 200 bytes to 10 Kbytes. Results, showing the data throughput to range from 0.2 to 1.1 Mbit/s, will be discussed.

  12. High-performance digital triggering system for phase-controlled rectifiers

    SciTech Connect

    Olsen, R.E.

    1983-01-01

    The larger power supplies used to power accelerator magnets are most commonly polyphase rectifiers using phase control. While this method is capable of handling impressive amounts of power, it suffers from one serious disadvantage, namely that of subharmonic ripple. Since the stability of the stored beam depends to a considerable extent on the regulation of the current in the bending magnets, subharmonic ripple, especially that of low frequency, can have a detrimental effect. At the NSLS, we have constructed a 12-pulse, phase control system using digital signal processing techniques that essentially eliminates subharmonic ripple.

  13. Expert Meeting. Recommended Approaches to Humidity Control in High Performance Homes

    SciTech Connect

    Rudd, Armin

    2013-07-01

    This meeting was held on October 16, 2012, in Westford, MA, and brought together experts in the field of residential humidity control to address modeling issues for dehumidification. The presentations and discussions centered on computer simulation and field experience with these systems, with the goal of developing foundational information to support the development of a Building America Measure Guideline on this topic.

  14. Performance of microprocessor controllers

    SciTech Connect

    Gates, R.S.; Turner, L.W.; Overhults, D.G. . Dept. of Agricultural Engineering)

    1992-01-01

    United States animal production systems are at the threshold of a major new method for daily management of environmental control -- the integrated microprocessor-based environmental control system. Widespread adoption of this technology has the potential for dramatic improvement in production efficiencies through lower management costs, improved energy savings, and better feed conversion efficiencies. However, the technical problems of transient surge protection and appropriate mechanical backup systems have not been adequately addressed by the industry. The goals of this research were to identify the degree to which transient surge protection was being provided by current manufacturers, and to illustrate the implementation of microprocessor environmental control systems with mechanical backup. Transient open circuit over-voltage tests (ANSI/IEEE C62.41-1980) were performed on 16 environmental control units: a maximum of 800 V spike was applied to the power supplies, and up to 100 V spike applied to temperature sensor lines. Under these relatively mild tests, no failures were noted due to power supply transients, but three units failed when subjected to transients on their temperature sensor lines. Mechanical backup systems were designed to provide essential life-support during critical conditions of extreme outside conditions and extreme animal densities. The design and installation of environmental control systems for (1) a gestation unit and (2) a broiler house was performed. An overview of the process, and difficulties noted, is presented. Both systems incorporated mechanical backups. 20 refs.

  15. High performance polymer development

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1991-01-01

    The term high performance as applied to polymers is generally associated with polymers that operate at high temperatures. High performance is used to describe polymers that perform at temperatures of 177 C or higher. In addition to temperature, other factors obviously influence the performance of polymers such as thermal cycling, stress level, and environmental effects. Some recent developments at NASA Langley in polyimides, poly(arylene ethers), and acetylenic terminated materials are discussed. The high performance/high temperature polymers discussed are representative of the type of work underway at NASA Langley Research Center. Further improvement in these materials as well as the development of new polymers will provide technology to help meet NASA future needs in high performance/high temperature applications. In addition, because of the combination of properties offered by many of these polymers, they should find use in many other applications.

  16. High Contrast Vacuum Nuller Testbed (VNT) Contrast, Performance and Null Control

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.

    2012-01-01

    Herein we report on our contrast assessment and the development, sensing and control of the Vacuum Nuller Testbed to realize a Visible Nulling Coronagraphy (VNC) for exoplanet detection and characterization. Tbe VNC is one of the few approaches that works with filled, segmented and sparse or diluted-aperture telescope systems. It thus spans a range of potential future NASA telescopes and could be flown as a separate instrument on such a future mission. NASA/Goddard Space Flight Center has an established effort to develop VNC technologies, and an incremental sequence of testbeds to advance this approach and its critical technologies. We discuss the development of the vacuum Visible Nulling Coronagraph testbed (VNT). The VNT is an ultra-stable vibration isolated testbed that operates under closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible-light nulling milestones with sequentially higher contrasts of 10(exp 8), 10(exp 9) and ideally 10(exp 10) at an inner working angle of 2*lambda/D. The VNT is based on a modified Mach-Zehnder nulling interferometer, with a "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. We discuss the laboratory results, optical configuration, critical technologies and the null sensing and control approach.

  17. High-Performance Metal/Carbide Composites with Far-From-Equilibrium Compositions and Controlled Microstructures

    PubMed Central

    Hu, Liangfa; O’Neil, Morgan; Erturun, Veysel; Benitez, Rogelio; Proust, Gwénaëlle; Karaman, Ibrahim; Radovic, Miladin

    2016-01-01

    The prospect of extending existing metal-ceramic composites to those with the compositions that are far from thermodynamic equilibrium is examined. A current and pressure-assisted, rapid infiltration is proposed to fabricate composites, consisting of reactive metallic and ceramic phases with controlled microstructure and tunable properties. An aluminum (Al) alloy/Ti2AlC composite is selected as an example of the far-from-equilibrium systems to fabricate, because Ti2AlC exists only in a narrow region of the Ti-Al-C phase diagram and readily reacts with Al. This kind of reactive systems challenges conventional methods for successfully processing corresponding metal-ceramic composites. Al alloy/Ti2AlC composites with controlled microstructures, various volume ratios of constituents (40/60 and 27/73) and metallic phase sizes (42–83 μm, 77–276 μm, and 167–545 μm), are obtained using the Ti2AlC foams with different pore structures as preforms for molten metal (Al alloy) infiltration. The resulting composites are lightweight and display exceptional mechanical properties at both ambient and elevated temperatures. These structures achieve a compressive strength that is 10 times higher than the yield strength of the corresponding peak-aged Al alloy at ambient temperature and 14 times higher at 400 °C. Possible strengthening mechanisms are described, and further strategies for improving properties of those composites are proposed. PMID:27752106

  18. Controlled Growth of Platinum Nanowire Arrays on Sulfur Doped Graphene as High Performance Electrocatalyst

    PubMed Central

    Wang, Rongyue; Higgins, Drew C.; Hoque, Md Ariful; Lee, DongUn; Hassan, Fathy; Chen, Zhongwei

    2013-01-01

    Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2–5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2–3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst. PMID:23942256

  19. High-performance perovskite light-emitting diodes via morphological control of perovskite films.

    PubMed

    Yu, Jae Choul; Kim, Da Bin; Jung, Eui Dae; Lee, Bo Ram; Song, Myoung Hoon

    2016-04-01

    Solution-processable perovskite materials have garnered tremendous attention because of their excellent charge carrier mobility, possibility of a tunable optical bandgap, and high photoluminescence quantum efficiency (PLQE). In particular, the uniform morphology of a perovskite film is the most important factor in realizing perovskite light-emitting diodes (PeLEDs) with high efficiency and full-coverage electroluminescence (EL). In this study, we demonstrate highly efficient PeLEDs that contain a perovskite film with a uniform morphology by introducing HBr into the perovskite precursor. The introduction of HBr into the perovskite precursor results in a perovskite film with a uniform, continuous morphology because the HBr increases the solubility of the inorganic component in the perovskite precursor and reduces the crystallization rate of the perovskite film upon spin-coating. Moreover, PeLEDs fabricated using perovskite films with a uniform, continuous morphology, which were deposited using 6 vol% HBr in a dimethylformamide (DMF)/hydrobromic acid (HBr) cosolvent, exhibited full coverage of the green EL emission. Finally, the optimized PeLEDs fabricated with perovskite films deposited using the DMF/HBr cosolvent exhibited a maximum luminance of 3490 cd m(-2) (at 4.3 V) and a luminous efficiency of 0.43 cd A(-1) (at 4.3 V). PMID:26607474

  20. Composite-Based High Performance Electroactive Polymers For Remotely Controlled Mechanical Manipulations in NASA Applications

    NASA Technical Reports Server (NTRS)

    Zhang, Q. M.

    2003-01-01

    This program supported investigation of an all-polymer percolative composite which exhibits very high dielectric constant (less than 7,000). The experimental results show that the dielectric behavior of this new class of percolative composites follows the prediction of the percolation theory and the analysis of the conductive percolation phenomena. The very high dielectric constant of the all-polymer composites which are also very flexible and possess elastic modulus not very much different from that of the insulation polymer matrix makes it possible to induce a high electromechanical response under a much reduced electric field (a strain of 2.65% with an elastic energy density of 0.18 J/cu cm can be achieved under a field of 16 MV/m). Data analysis also suggests that in these composites, the non-uniform local field distribution as well as interface effects can significantly enhance the strain responses. Furthermore, the experimental data as well as the data analysis indicate that the conduction loss in these composites will not affect the strain hysteresis.

  1. High-performance perovskite light-emitting diodes via morphological control of perovskite films

    NASA Astrophysics Data System (ADS)

    Yu, Jae Choul; Kim, Da Bin; Jung, Eui Dae; Lee, Bo Ram; Song, Myoung Hoon

    2016-03-01

    Solution-processable perovskite materials have garnered tremendous attention because of their excellent charge carrier mobility, possibility of a tunable optical bandgap, and high photoluminescence quantum efficiency (PLQE). In particular, the uniform morphology of a perovskite film is the most important factor in realizing perovskite light-emitting diodes (PeLEDs) with high efficiency and full-coverage electroluminescence (EL). In this study, we demonstrate highly efficient PeLEDs that contain a perovskite film with a uniform morphology by introducing HBr into the perovskite precursor. The introduction of HBr into the perovskite precursor results in a perovskite film with a uniform, continuous morphology because the HBr increases the solubility of the inorganic component in the perovskite precursor and reduces the crystallization rate of the perovskite film upon spin-coating. Moreover, PeLEDs fabricated using perovskite films with a uniform, continuous morphology, which were deposited using 6 vol% HBr in a dimethylformamide (DMF)/hydrobromic acid (HBr) cosolvent, exhibited full coverage of the green EL emission. Finally, the optimized PeLEDs fabricated with perovskite films deposited using the DMF/HBr cosolvent exhibited a maximum luminance of 3490 cd m-2 (at 4.3 V) and a luminous efficiency of 0.43 cd A-1 (at 4.3 V).Solution-processable perovskite materials have garnered tremendous attention because of their excellent charge carrier mobility, possibility of a tunable optical bandgap, and high photoluminescence quantum efficiency (PLQE). In particular, the uniform morphology of a perovskite film is the most important factor in realizing perovskite light-emitting diodes (PeLEDs) with high efficiency and full-coverage electroluminescence (EL). In this study, we demonstrate highly efficient PeLEDs that contain a perovskite film with a uniform morphology by introducing HBr into the perovskite precursor. The introduction of HBr into the perovskite precursor results in

  2. Closed-Loop System Identification Experience for Flight Control Law and Flying Qualities Evaluation of a High Performance Fighter Aircraft

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick C.

    1999-01-01

    This paper highlights some of the results and issues associated with estimating models to evaluate control law design methods and design criteria for advanced high performance aircraft. Experimental fighter aircraft such as the NASA High Alpha Research Vehicle (HARV) have the capability to maneuver at very high angles of attack where nonlinear aerodynamics often predominate. HARV is an experimental F/A-18, configured with thrust vectoring and conformal actuated nose strakes. Identifying closed-loop models for this type of aircraft can be made difficult by nonlinearities and high-order characteristics of the system. In this paper only lateral-directional axes are considered since the lateral-directional control law was specifically designed to produce classical airplane responses normally expected with low-order, rigid-body systems. Evaluation of the control design methodology was made using low-order equivalent systems determined from flight and simulation. This allowed comparison of the closed-loop rigid-body dynamics achieved in flight with that designed in simulation. In flight, the On Board Excitation System was used to apply optimal inputs to lateral stick and pedals at five angles of attack: 5, 20, 30, 45, and 60 degrees. Data analysis and closed-loop model identification were done using frequency domain maximum likelihood. The structure of the identified models was a linear state-space model reflecting classical 4th-order airplane dynamics. Input time delays associated with the high-order controller and aircraft system were accounted for in data preprocessing. A comparison of flight estimated models with small perturbation linear design models highlighted nonlinearities in the system and indicated that the estimated closed-loop rigid-body dynamics were sensitive to input amplitudes at 20 and 30 degrees angle of attack.

  3. Closed-Loop System Identification Experience for Flight Control Law and Flying Qualities Evaluation of a High Performance Fighter Aircraft

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick C.

    1996-01-01

    This paper highlights some of the results and issues associated with estimating models to evaluate control law design methods and design criteria for advanced high performance aircraft. Experimental fighter aircraft such as the NASA-High Alpha Research Vehicle (HARV) have the capability to maneuver at very high angles of attack where nonlinear aerodynamics often predominate. HARV is an experimental F/A-18, configured with thrust vectoring and conformal actuated nose strakes. Identifying closed-loop models for this type of aircraft can be made difficult by nonlinearities and high order characteristics of the system. In this paper, only lateral-directional axes are considered since the lateral-directional control law was specifically designed to produce classical airplane responses normally expected with low-order, rigid-body systems. Evaluation of the control design methodology was made using low-order equivalent systems determined from flight and simulation. This allowed comparison of the closed-loop rigid-body dynamics achieved in flight with that designed in simulation. In flight, the On Board Excitation System was used to apply optimal inputs to lateral stick and pedals at five angles at attack : 5, 20, 30, 45, and 60 degrees. Data analysis and closed-loop model identification were done using frequency domain maximum likelihood. The structure of identified models was a linear state-space model reflecting classical 4th-order airplane dynamics. Input time delays associated with the high-order controller and aircraft system were accounted for in data preprocessing. A comparison of flight estimated models with small perturbation linear design models highlighted nonlinearities in the system and indicated that the closed-loop rigid-body dynamics were sensitive to input amplitudes at 20 and 30 degrees angle of attack.

  4. Performance of high-area-ratio annular dump diffuser using suction-stabilized-vortex flow control

    NASA Technical Reports Server (NTRS)

    Juhasz, A. J.; Smith, J. M.

    1977-01-01

    A short annular dump diffuser having a geometry conductive to formation of suction stabilized toroidal vortices in the region of abrupt area change was tested. The overall diffuser area ratio was 4.0 and the length to inlet height ratio was 2.0. Performance data were obtained at near ambient temperature and pressure for inlet Mach numbers of 0.18 and 0.30 with suction rates ranging from 0 to 18 percent of total inlet mass flowrate. Results show that the exit velocity profile could be readily biased toward either wall by adjustment of inner and outer wall suction rates. Symmetric exit velocity profiles were inherently unstable with a tendency to revert to a hub or tip bias. Diffuser effectiveness was increased from about 38 percent without suction to over 85 percent at a total suction rate of 10 to 12 percent. At the same time diffuser total pressure loss was reduced from 3.1 percent to 1.1 percent at an inlet Mach number of 0.3.

  5. High-performance super capacitors based on activated anthracite with controlled porosity

    NASA Astrophysics Data System (ADS)

    Lee, Hyun-Chul; Byamba-Ochir, Narandalai; Shim, Wang-Geun; Balathanigaimani, M. S.; Moon, Hee

    2015-02-01

    Mongolian anthracite is chemically activated using potassium hydroxide as an activation agent to make activated carbon materials. Prior to the chemical activation, the chemical agent is introduced by two different methods as follows, (1) simple physical mixing, (2) impregnation. The physical properties such as specific surface area, pore volume, pore size distribution, and adsorption energy distribution are measured to assess them as carbon electrode materials for electric double-layer capacitors (EDLC). The surface functional groups and morphology are also characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analyses respectively. The electrochemical results for the activated carbon electrodes in 3 M sulfuric acid electrolyte solution indicate that the activated Mongolian anthracite has relatively large specific capacitances in the range of 120-238 F g-1 and very high electrochemical stability, as they keep more than 98% of initial capacitances until 1000 charge/discharge cycles.

  6. Turbulence Decorrelation via Controlled Ex B Shear in High-Performance Plasmas

    NASA Astrophysics Data System (ADS)

    McKee, G. R.

    2015-11-01

    Multi-scale spatiotemporal turbulence properties are significantly altered as toroidal rotation and resulting ExB shearing rate profile are systematically varied in advanced-inductive H-mode plasmas on DIII-D (βN ~ 2.7, q95=5.1). Density, electron and ion temperature profiles and dimensionless parameters (βN, q95, ν*, ρ*, and Te/Ti) are maintained nearly fixed during the rotation scan. Low-wavenumber turbulence (k⊥ρS < 1), measured with Beam Emission Spectroscopy, exhibits increased decorrelation rates (reduced eddy lifetime) as the ExB shear rises across the radial zone of maximum shearing rate (0.55 < ρ < 0 . 75), while the fluctuation amplitude undergoes little change. The poloidal wavenumber is reduced at higher shear, indicating a change in the wavenumber spectrum: eddies elongate in the direction orthogonal to shear and field. At both low and high shear, the 2D turbulence correlation function exhibits a tilted structure, consistent with flow shear. At mid-radius (ρ ~ 0.5), low-k density fluctuations show localized amplitude reduction, consistent with linear GYRO growth rates and ωExB shearing rates. Intermediate and high wavenumber fluctuations measured with Doppler Back-Scattering (k⊥ρS ~ 2.5-3.5) at ρ=0.7 and Phase Contrast Imaging (k⊥ρS > 5) exhibit decreasing amplitude at higher rotation. The energy confinement time increases from 105 ms to 150 ms as the toroidal Mach number (M=vTOR / vth , i) increases to Mo ~ 0.5, while transport decreases. TGLF calculations match the Ti profile with modest discrepancies in the Te and ne profiles. These results clarify the complex mechanisms by which ExB shear affects turbulence. Work supported in part by the US DOE under DE-FG02-08ER54999, DE-FC02-04ER54698.

  7. High performance systems

    SciTech Connect

    Vigil, M.B.

    1995-03-01

    This document provides a written compilation of the presentations and viewgraphs from the 1994 Conference on High Speed Computing given at the High Speed Computing Conference, {open_quotes}High Performance Systems,{close_quotes} held at Gleneden Beach, Oregon, on April 18 through 21, 1994.

  8. High Performance Polymers

    NASA Technical Reports Server (NTRS)

    Venumbaka, Sreenivasulu R.; Cassidy, Patrick E.

    2003-01-01

    This report summarizes results from research on high performance polymers. The research areas proposed in this report include: 1) Effort to improve the synthesis and to understand and replicate the dielectric behavior of 6HC17-PEK; 2) Continue preparation and evaluation of flexible, low dielectric silicon- and fluorine- containing polymers with improved toughness; and 3) Synthesis and characterization of high performance polymers containing the spirodilactam moiety.

  9. TiO2 microboxes with controlled internal porosity for high-performance lithium storage

    SciTech Connect

    Gao, Xuehui; Li, Gaoran; Xu, Yangyang; Hong, Zhanglian; Liang, Chengdu; Lin, Zhan

    2015-10-02

    Titanium dioxide (TiO2) is considered a promising anode material for high-power lithium ion batteries (LIBs) because of its low cost, high thermal/chemical stability, and good safety performance without solid electrolyte interface formation. However, the poor electronic conductivity and low lithium ion diffusivity of TiO2 result in poor cyclability and lithium ion depletion at high current rates, which hinder them from practical applications. Herein we demonstrate that hierarchically structured TiO2 microboxes with controlled internal porosity can address the aforementioned problems for high-power, long-life LIB anodes. A self-templating method for the synthesis of mesoporous microboxes was developed through Na2EDTA-assisted ion exchange of CaTiO3 microcubes. The resulting TiO2 nanorods were organized into microboxes that resemble the microcube precursors. Furthermore, this nanostructured TiO2 material has superior lithium storage properties with a capacity of 187 mAh g-1 after 300 cycles at 1C and good rate capabilities up to 20C.

  10. Facet-Controlling Agents Free Synthesis of Hematite Crystals with High-Index Planes: Excellent Photodegradation Performance and Mechanism Insight.

    PubMed

    Ding, Dahu; Huang, Yang; Zhou, Cuifeng; Liu, Zongwen; Ren, Jichang; Zhang, Ruiqin; Wang, Jianhai; Zhang, Yuanjian; Lei, Zhongfang; Zhang, Zhenya; Zhi, Chunyi

    2016-01-13

    Hematite (α-Fe2O3) crystals with uniform size and structure are synthesized through very facile one-pot hydrothermal methods without any additive. The as-synthesized sub-micrometer-sized α-Fe2O3 crystals with small surface areas perform superb visible light photodegradation activities, even much better than most other α-Fe2O3 nanostructures with large surface areas. Profound mechanism analyses reveal that the microwave-assisted hydrothermal (Mic-H) synthesized α-Fe2O3 is enclosed by 12 high-index {2-15} facets. The structure and the low unoccupied molecular orbital (LUMO) of the high-index planes result in the excellent photocatalytic activity. This is the first report on the formation of {2-15} plane group of hematite, and the synthesis of the hematite particles with the {2-15} planes is very simple and no any facet-controlling agent is used. This study may pave the way to further performance enhancement and practical applications of the cheap hematite materials.

  11. Solid State Digital Propulsion "Cluster Thrusters" For Small Satellites Using High Performance Electrically Controlled Extinguishable Solid Propellants (ECESP)

    NASA Technical Reports Server (NTRS)

    Sawka, Wayne N.; Katzakian, Arthur; Grix, Charles

    2005-01-01

    Electrically controlled extinguishable solid propellants (ESCSP) are capable of multiple ignitions, extinguishments and throttle control by the application of electrical power. Both core and end burning no moving parts ECESP grains/motors to three inches in diameter have now been tested. Ongoing research has led to a newer family of even higher performance ECESP providing up to 10% higher performance, manufacturing ease, and significantly higher electrical conduction. The high conductivity was not found to be desirable for larger motors; however it is ideal for downward scaling to micro and pico- propulsion applications with a web thickness of less than 0.125 inch/ diameter. As a solid solution propellant, this ECESP is molecularly uniform, having no granular structure. Because of this homogeneity and workable viscosity it can be directly cast into thin layers or vacuum cast into complex geometries. Both coaxial and grain stacks have been demonstrated. Combining individual propellant coaxial grains and/or grain stacks together form three-dimensional arrays yield modular cluster thrusters. Adoption of fabless manufacturing methods and standards from the electronics industry will provide custom, highly reproducible micro-propulsion arrays and clusters at low costs. These stack and cluster thruster designs provide a small footprint saving spacecraft surface area for solar panels and/or experiments. The simplicity of these thrusters will enable their broad use on micro-pico satellites for primary propulsion, ACS and formation flying applications. Larger spacecraft may find uses for ECESP thrusters on extended booms, on-orbit refueling, pneumatic actuators, and gas generators.

  12. Preparation of morphology-controllable polyaniline and polyaniline/graphene hydrogels for high performance binder-free supercapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Luo, Jinwei; Zhong, Wenbin; Zou, Yubo; Xiong, Changlun; Yang, Wantai

    2016-07-01

    Polyaniline (PANI) and its composite hydrogels have been considered as a unique supercapacitor electrode material due to their three dimensional (3D) porous structures, formed conducting networks, high specific surface areas and fast electron/ion transfer. Herein, dendritic and long fibrous PANI nanostructure hydrogels (PDH and PFH), dendritic PNAI nanofiber/graphene and long PANI nanofibers/Nitrogen-doped graphene composite hydrogels (PGH and PNGH) were prepared by integration polymerization of aniline and hydrothermal process. It was found that the addition of p-Phenylenediamine (PPD) not only controlled the morphologies of PANI from dendritic to long fibrous, but also facilitated the graphene oxide (GO) into nitrogen-doped graphene. Furthermore, after freeze-drying, PDH and PGH exhibited a max compressive strength of 9.5 and 9.6 KPa, respectively; while the max compressive strength of PFH and PNGH constructed with long PANI nanofiber is 79.9 and 75.8 KPa, respectively. Directly using these prepared hydrogels as electrodes for supercapacitors, it was found that PDH, PFH, PGH and PNGH exhibited high specific capacitances of 448.6, 470, 540.9 and 610 F g-1, respectively, at the current density of 1 A g-1. It is expected that the prepared PDH, PFH, PGH and PNGH can be directly applied in the field of high performance energy storage devices.

  13. High-performance flat data center network architecture based on scalable and flow-controlled optical switching system

    NASA Astrophysics Data System (ADS)

    Calabretta, Nicola; Miao, Wang; Dorren, Harm

    2016-03-01

    Traffic in data centers networks (DCNs) is steadily growing to support various applications and virtualization technologies. Multi-tenancy enabling efficient resource utilization is considered as a key requirement for the next generation DCs resulting from the growing demands for services and applications. Virtualization mechanisms and technologies can leverage statistical multiplexing and fast switch reconfiguration to further extend the DC efficiency and agility. We present a novel high performance flat DCN employing bufferless and distributed fast (sub-microsecond) optical switches with wavelength, space, and time switching operation. The fast optical switches can enhance the performance of the DCNs by providing large-capacity switching capability and efficiently sharing the data plane resources by exploiting statistical multiplexing. Benefiting from the Software-Defined Networking (SDN) control of the optical switches, virtual DCNs can be flexibly created and reconfigured by the DCN provider. Numerical and experimental investigations of the DCN based on the fast optical switches show the successful setup of virtual network slices for intra-data center interconnections. Experimental results to assess the DCN performance in terms of latency and packet loss show less than 10^-5 packet loss and 640ns end-to-end latency with 0.4 load and 16- packet size buffer. Numerical investigation on the performance of the systems when the port number of the optical switch is scaled to 32x32 system indicate that more than 1000 ToRs each with Terabit/s interface can be interconnected providing a Petabit/s capacity. The roadmap to photonic integration of large port optical switches will be also presented.

  14. Introduction to Cost Control Strategies for Zero Energy Buildings: High-Performance Design and Construction on a Budget (Fact Sheet)

    SciTech Connect

    Not Available

    2014-09-01

    Momentum behind zero energy building design and construction is increasing, presenting a tremendous opportunity for advancing energy performance in the commercial building industry. At the same time, there is a lingering perception that zero energy buildings must be cost prohibitive or limited to showcase projects. Fortunately, an increasing number of projects are demonstrating that high performance can be achieved within typical budgets. This factsheet highlights replicable, recommended strategies for achieving high performance on a budget, based on experiences from past projects.

  15. High-Performance WSe2 Field-Effect Transistors via Controlled Formation of In-Plane Heterojunctions.

    PubMed

    Liu, Bilu; Ma, Yuqiang; Zhang, Anyi; Chen, Liang; Abbas, Ahmad N; Liu, Yihang; Shen, Chenfei; Wan, Haochuan; Zhou, Chongwu

    2016-05-24

    Monolayer WSe2 is a two-dimensional (2D) semiconductor with a direct band gap, and it has been recently explored as a promising material for electronics and optoelectronics. Low field-effect mobility is the main constraint preventing WSe2 from becoming one of the competing channel materials for field-effect transistors (FETs). Recent results have demonstrated that chemical treatments can modify the electrical properties of transition metal dichalcogenides (TMDCs), including MoS2 and WSe2. Here, we report that controlled heating in air significantly improves device performance of WSe2 FETs in terms of on-state currents and field-effect mobilities. Specifically, after being heated at optimized conditions, chemical vapor deposition grown monolayer WSe2 FETs showed an average FET mobility of 31 cm(2)·V(-1)·s(-1) and on/off current ratios up to 5 × 10(8). For few-layer WSe2 FETs, after the same treatment applied, we achieved a high mobility up to 92 cm(2)·V(-1)·s(-1). These values are significantly higher than FETs fabricated using as-grown WSe2 flakes without heating treatment, demonstrating the effectiveness of air heating on the performance improvements of WSe2 FETs. The underlying chemical processes involved during air heating and the formation of in-plane heterojunctions of WSe2 and WO3-x, which is believed to be the reason for the improved FET performance, were studied by spectroscopy and transmission electron microscopy. We further demonstrated that, by combining the air heating method developed in this work with supporting 2D materials on the BN substrate, we achieved a noteworthy field-effect mobility of 83 cm(2)·V(-1)·s(-1) for monolayer WSe2 FETs. This work is a step toward controlled modification of the properties of WSe2 and potentially other TMDCs and may greatly improve device performance for future applications of 2D materials in electronics and optoelectronics. PMID:27159780

  16. High performance polymeric foams

    SciTech Connect

    Gargiulo, M.; Sorrentino, L.; Iannace, S.

    2008-08-28

    The aim of this work was to investigate the foamability of high-performance polymers (polyethersulfone, polyphenylsulfone, polyetherimide and polyethylenenaphtalate). Two different methods have been used to prepare the foam samples: high temperature expansion and two-stage batch process. The effects of processing parameters (saturation time and pressure, foaming temperature) on the densities and microcellular structures of these foams were analyzed by using scanning electron microscopy.

  17. DSP-based adaptive backstepping using the tracking errors for high-performance sensorless speed control of induction motor drive.

    PubMed

    Zaafouri, Abderrahmen; Ben Regaya, Chiheb; Ben Azza, Hechmi; Châari, Abdelkader

    2016-01-01

    This paper presents a modified structure of the backstepping nonlinear control of the induction motor (IM) fitted with an adaptive backstepping speed observer. The control design is based on the backstepping technique complemented by the introduction of integral tracking errors action to improve its robustness. Unlike other research performed on backstepping control with integral action, the control law developed in this paper does not propose the increase of the number of system state so as not increase the complexity of differential equations resolution. The digital simulation and experimental results show the effectiveness of the proposed control compared to the conventional PI control. The results analysis shows the characteristic robustness of the adaptive control to disturbances of the load, the speed variation and low speed.

  18. Bioreactor control improves bioprocess performance.

    PubMed

    Simutis, Rimvydas; Lübbert, Andreas

    2015-08-01

    The performance of bioreactors is not only determined by productivity but also by process quality, which is mainly determined by variances in the process variables. As fluctuations in these quantities directly affect the variability in the product properties, combatting distortions is the main task of practical quality assurance. The straightforward way of reducing this variability is keeping the product formation process tightly under control. Purpose of this keynote is to show that there is enough evidence in literature showing that the performance of the fermentation processes can significantly be improved by feedback control. Most of the currently used open loop control procedures can be replaced by relatively simple feedback techniques. It is shown by practical examples that such a retrofitting does not require significant changes in the well-established equipment. Feedback techniques are best in assuring high reproducibility of the industrial cultivation processes and thus in assuring the quality of their products. Many developments in supervising and controlling industrial fermentations can directly be taken over in manufacturing processes. Even simple feedback controllers can efficiently improve the product quality. It's the time now that manufacturers follow the developments in most other industries and improve process quality by automatic feedback control. PMID:26228573

  19. Bioreactor control improves bioprocess performance.

    PubMed

    Simutis, Rimvydas; Lübbert, Andreas

    2015-08-01

    The performance of bioreactors is not only determined by productivity but also by process quality, which is mainly determined by variances in the process variables. As fluctuations in these quantities directly affect the variability in the product properties, combatting distortions is the main task of practical quality assurance. The straightforward way of reducing this variability is keeping the product formation process tightly under control. Purpose of this keynote is to show that there is enough evidence in literature showing that the performance of the fermentation processes can significantly be improved by feedback control. Most of the currently used open loop control procedures can be replaced by relatively simple feedback techniques. It is shown by practical examples that such a retrofitting does not require significant changes in the well-established equipment. Feedback techniques are best in assuring high reproducibility of the industrial cultivation processes and thus in assuring the quality of their products. Many developments in supervising and controlling industrial fermentations can directly be taken over in manufacturing processes. Even simple feedback controllers can efficiently improve the product quality. It's the time now that manufacturers follow the developments in most other industries and improve process quality by automatic feedback control.

  20. Thermal effects on the dynamics and motor control of ballistic prey capture in toads: maintaining high performance at low temperature.

    PubMed

    Deban, Stephen M; Lappin, A Kristopher

    2011-04-15

    Temperature has a strong influence on biological rates, including the contractile rate properties of muscle and thereby the velocity, acceleration and power of muscle-powered movements. We hypothesized that the dynamics of movements powered by elastic recoil have a lower thermal dependence than muscle-powered movements. We examined the prey capture behavior of toads (Bufo terrestris) using high speed imaging and electromyography to compare the effects of body temperature (11-35°C) on the kinematics, dynamics and motor control of two types of movement: (1) ballistic mouth opening and tongue projection, which are powered by elastic recoil, and (2) non-ballistic prey transport, including tongue retraction and mouth closing, which are powered directly by muscle contraction. Over 11-25°C, temperature coefficients of ballistic mouth opening and tongue projection dynamics (Q(10) of 0.99-1.25) were not significantly different from 1.00 and were consistently lower than those of prey transport movements (Q(10) of 1.77-2.26), supporting our main hypothesis. The depressor mandibulae muscle, which is responsible for ballistic mouth opening and tongue projection via the recovery of elastic strain energy stored by the muscle prior to the onset of the movement, was activated earlier and for a longer duration at lower temperatures (Q(10) of 2.29-2.41), consistent with a slowing of its contractile rates. Muscle recruitment was unaffected by temperature, as revealed by the lack of thermal dependence in the intensity of activity of both the jaw depressor and jaw levator muscles (Q(10) of 0.754-1.12). Over the 20-35°C range, lower thermal dependence was found for the dynamics of non-elastic movements and the motor control of both elastic and non-elastic movements, in accord with a plateau of high performance found in other systems.

  1. High performance parallel architectures

    SciTech Connect

    Anderson, R.E. )

    1989-09-01

    In this paper the author describes current high performance parallel computer architectures. A taxonomy is presented to show computer architecture from the user programmer's point-of-view. The effects of the taxonomy upon the programming model are described. Some current architectures are described with respect to the taxonomy. Finally, some predictions about future systems are presented. 5 refs., 1 fig.

  2. High-Performance Happy

    ERIC Educational Resources Information Center

    O'Hanlon, Charlene

    2007-01-01

    Traditionally, the high-performance computing (HPC) systems used to conduct research at universities have amounted to silos of technology scattered across the campus and falling under the purview of the researchers themselves. This article reports that a growing number of universities are now taking over the management of those systems and…

  3. High-Performance Integrated Control of water quality and quantity in urban water reservoirs by dynamic emulation and model predictive control

    NASA Astrophysics Data System (ADS)

    Castelletti, A.; Galelli, S.; Goedbloed, A.

    2015-12-01

    Retention basins and urban reservoirs are increasingly used to support drinking water supply in large metropolitan contexts, since they make use of a resource, i.e., stormwater, that would be otherwise wasted, thus limiting the amount of water extracted from natural systems or produced with energy-intensive techniques. Yet, the operation of these infrastructures faces a twofold challenge. First, the presence of large impervious areas in urban catchments results in high discharge peaks and runoff volumes and a fast runoff response to rainfall, with consequent very short times of concentration. Second, stormwater transports large amount of pollutants to the receiving water bodies. This paper contributes a novel High-Performance Integrated Control framework to support the real-time operation of urban water supply storages affected by water quality problems. We use a 3D hydrodynamic, high-fidelity, simulation model to predict the main water quality dynamics and inform a real-time controller based on Model Predictive Control. We integrate the simulation model into the control scheme by a model reduction process, where the high-fidelity simulator is first used to identify and then replaced by a low-order dynamic emulator, which runs orders of magnitude faster. The framework is used to design the hourly operation of Marina Reservoir, a 3.2 Mm3 stormwater-fed reservoir located in the centre of Singapore operated for drinking water supply and flood control. Because of its recent formation from a former estuary, the reservoir suffers from high salinity levels, whose dynamics is modelled with Delft3D-FLOW. Results show that the real-time operation designed by our framework drops the minimum salinity levels of nearly 30% while reducing the average annual deficit of drinking water supply by about two times the active storage of the reservoir. Such a win-win solution is obtained by means of a model reduction process that reduced the dimensionality of Delft3D-FLOW by three orders

  4. A Method for Integrating Thrust-Vectoring and Actuated Forebody Strakes with Conventional Aerodynamic Controls on a High-Performance Fighter Airplane

    NASA Technical Reports Server (NTRS)

    Lallman, Frederick J.; Davidson, John B.; Murphy, Patrick C.

    1998-01-01

    A method, called pseudo controls, of integrating several airplane controls to achieve cooperative operation is presented. The method eliminates conflicting control motions, minimizes the number of feedback control gains, and reduces the complication of feedback gain schedules. The method is applied to the lateral/directional controls of a modified high-performance airplane. The airplane has a conventional set of aerodynamic controls, an experimental set of thrust-vectoring controls, and an experimental set of actuated forebody strakes. The experimental controls give the airplane additional control power for enhanced stability and maneuvering capabilities while flying over an expanded envelope, especially at high angles of attack. The flight controls are scheduled to generate independent body-axis control moments. These control moments are coordinated to produce stability-axis angular accelerations. Inertial coupling moments are compensated. Thrust-vectoring controls are engaged according to their effectiveness relative to that of the aerodynamic controls. Vane-relief logic removes steady and slowly varying commands from the thrust-vectoring controls to alleviate heating of the thrust turning devices. The actuated forebody strakes are engaged at high angles of attack. This report presents the forward-loop elements of a flight control system that positions the flight controls according to the desired stability-axis accelerations. This report does not include the generation of the required angular acceleration commands by means of pilot controls or the feedback of sensed airplane motions.

  5. Controlled modification of carbon nanotubes and polyaniline on macroporous graphite felt for high-performance microbial fuel cell anode

    NASA Astrophysics Data System (ADS)

    Cui, Hui-Fang; Du, Lin; Guo, Peng-Bo; Zhu, Bao; Luong, John H. T.

    2015-06-01

    Polyaniline (PANI) was electropolymerized on the surface of macroporous graphite felt (GF) followed by the electrophoretic deposition of carbon nanotubes (CNTs). The as-prepared macroporous material was characterized by scanning electron microscopy, water contact angle goniometry and electrochemical techniques. Upon the modification of PANI, a rough and nano-cilia containing film is coated on the surface of the graphite fibers, transforming the surface from hydrophobic to hydrophilic. The subsequent modification by CNTs increases the effective surface area and electrical conductivity of the resulting material. The power output of a mediator-free dual-chamber microbial fuel cell (MFC) constructed from the GF anode and an exoelectrogen Shewanella putrefaciens increases drastically with the CNT modification. The CNT/PANI/GF MFC attains an output voltage of 342 mV across an external resistor of 1.96 kΩ constant load, and a maximum power density of 257 mW m-2, increased by 343% and 186%, compared to that of the pristine GF MFC and the PANI/GF MFC, respectively. More bacteria are attached on the CNT/PANI/GF anode than on the PANI/GF anode during the working of the MFC. This strategy provides an easy scale-up, simple and controllable method for the preparation of high-performance and low-cost MFC anodes.

  6. High Performance Window Retrofit

    SciTech Connect

    Shrestha, Som S; Hun, Diana E; Desjarlais, Andre Omer

    2013-12-01

    The US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and Traco partnered to develop high-performance windows for commercial building that are cost-effective. The main performance requirement for these windows was that they needed to have an R-value of at least 5 ft2 F h/Btu. This project seeks to quantify the potential energy savings from installing these windows in commercial buildings that are at least 20 years old. To this end, we are conducting evaluations at a two-story test facility that is representative of a commercial building from the 1980s, and are gathering measurements on the performance of its windows before and after double-pane, clear-glazed units are upgraded with R5 windows. Additionally, we will use these data to calibrate EnergyPlus models that we will allow us to extrapolate results to other climates. Findings from this project will provide empirical data on the benefits from high-performance windows, which will help promote their adoption in new and existing commercial buildings. This report describes the experimental setup, and includes some of the field and simulation results.

  7. High performance satellite networks

    NASA Astrophysics Data System (ADS)

    Helm, Neil R.; Edelson, Burton I.

    1997-06-01

    The high performance satellite communications networks of the future will have to be interoperable with terrestrial fiber cables. These satellite networks will evolve from narrowband analogue formats to broadband digital transmission schemes, with protocols, algorithms and transmission architectures that will segment the data into uniform cells and frames, and then transmit these data via larger and more efficient synchronous optional (SONET) and asynchronous transfer mode (ATM) networks that are being developed for the information "superhighway". These high performance satellite communications and information networks are required for modern applications, such as electronic commerce, digital libraries, medical imaging, distance learning, and the distribution of science data. In order for satellites to participate in these information superhighway networks, it is essential that they demonstrate their ability to: (1) operate seamlessly with heterogeneous architectures and applications, (2) carry data at SONET rates with the same quality of service as optical fibers, (3) qualify transmission delay as a parameter not a problem, and (4) show that satellites have several performance and economic advantages over fiber cable networks.

  8. High Performance Buildings Database

    DOE Data Explorer

    The High Performance Buildings Database is a shared resource for the building industry, a unique central repository of in-depth information and data on high-performance, green building projects across the United States and abroad. The database includes information on the energy use, environmental performance, design process, finances, and other aspects of each project. Members of the design and construction teams are listed, as are sources for additional information. In total, up to twelve screens of detailed information are provided for each project profile. Projects range in size from small single-family homes or tenant fit-outs within buildings to large commercial and institutional buildings and even entire campuses. The database is a data repository as well. A series of Web-based data-entry templates allows anyone to enter information about a building project into the database. Once a project has been submitted, each of the partner organizations can review the entry and choose whether or not to publish that particular project on its own Web site.

  9. High User Control in Game Design Elements Increases Compliance and In-game Performance in a Memory Training Game.

    PubMed

    Nagle, Aniket; Riener, Robert; Wolf, Peter

    2015-01-01

    Computer games are increasingly being used for training cognitive functions like working memory and attention among the growing population of older adults. While cognitive training games often include elements like difficulty adaptation, rewards, and visual themes to make the games more enjoyable and effective, the effect of different degrees of afforded user control in manipulating these elements has not been systematically studied. To address this issue, two distinct implementations of the three aforementioned game elements were tested among healthy older adults (N = 21, 69.9 ± 6.4 years old) playing a game-like version of the n-back task on a tablet at home for 3 weeks. Two modes were considered, differentiated by the afforded degree of user control of the three elements: user control of difficulty vs. automatic difficulty adaptation, difficulty-dependent rewards vs. automatic feedback messages, and user choice of visual theme vs. no choice. The two modes ("USER-CONTROL" and "AUTO") were compared for frequency of play, duration of play, and in-game performance. Participants were free to play the game whenever and for however long they wished. Participants in USER-CONTROL exhibited significantly higher frequency of playing, total play duration, and in-game performance than participants in AUTO. The results of the present study demonstrate the efficacy of providing user control in the three game elements, while validating a home-based study design in which participants were not bound by any training regimen, and could play the game whenever they wished. The results have implications for designing cognitive training games that elicit higher compliance and better in-game performance, with an emphasis on home-based training. PMID:26635681

  10. High Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  11. Effects of high energy simulated space radiation on polymeric second-surface mirrors. [thermal control coatings - performance tests

    NASA Technical Reports Server (NTRS)

    Eogdall, L. B.; Cannaday, S. S.

    1975-01-01

    A radiation effects experimental program was performed, in which second surface mirror type thermal control coatings were exposed to ultraviolet radiation, electrons, and protons simultaneously. Stability was assessed by making periodic spectral reflectance measurements in situ (and in air after testing for comparison). Solar absorption coefficients were derived by computer. Many of the exposed materials showed large amounts of degradation in reflectance absorptance, principally due to the electron exposure. A series of tests was conducted, leading to the identification of a modified second surface mirror that shows considerable improvement and promise for stability during thermal control applications in a charged particle space radiation environment.

  12. High-performance electrode for medium-temperature solid oxide fuel cells. Control of microstructure of ceria-based anodes with highly dispersed ruthenium electrocatalysts

    SciTech Connect

    Uchida, Hiroyuki; Osuga, Takashi; Watanabe, Masahiro

    1999-05-01

    In order to enhance gas-diffusion rates in a mixed-conducting samaria-doped ceria (SDC) anode, micrometer-sized pores were prepared by sintering a SDC paste containing fine polymer beads (d = 1.2 {micro}m) coated on an yttria-stabilized zirconia electrolyte. SDC anodes prepared under different conditions were examined to determine their pore-size distribution, pore volume, ohmic resistance, polarization behavior, and morphological structure. Both the anodic overpotential and the ohmic resistance of SDC anodes were lowered appreciably by controlling their microstructures. The performance of a SDC anode with optimized microstructure was enhanced further with highly dispersed Ru catalysts at 3 wt % loading, especially at low operating temperatures at about 800 C. The current density on a Ru-SDC anode at an overpotential of 0.1 V was 0.5 A/cm{sup 2} at 800 C.

  13. High Performance Parallel Architectures

    NASA Technical Reports Server (NTRS)

    El-Ghazawi, Tarek; Kaewpijit, Sinthop

    1998-01-01

    Traditional remote sensing instruments are multispectral, where observations are collected at a few different spectral bands. Recently, many hyperspectral instruments, that can collect observations at hundreds of bands, have been operational. Furthermore, there have been ongoing research efforts on ultraspectral instruments that can produce observations at thousands of spectral bands. While these remote sensing technology developments hold great promise for new findings in the area of Earth and space science, they present many challenges. These include the need for faster processing of such increased data volumes, and methods for data reduction. Dimension Reduction is a spectral transformation, aimed at concentrating the vital information and discarding redundant data. One such transformation, which is widely used in remote sensing, is the Principal Components Analysis (PCA). This report summarizes our progress on the development of a parallel PCA and its implementation on two Beowulf cluster configuration; one with fast Ethernet switch and the other with a Myrinet interconnection. Details of the implementation and performance results, for typical sets of multispectral and hyperspectral NASA remote sensing data, are presented and analyzed based on the algorithm requirements and the underlying machine configuration. It will be shown that the PCA application is quite challenging and hard to scale on Ethernet-based clusters. However, the measurements also show that a high- performance interconnection network, such as Myrinet, better matches the high communication demand of PCA and can lead to a more efficient PCA execution.

  14. High User Control in Game Design Elements Increases Compliance and In-game Performance in a Memory Training Game

    PubMed Central

    Nagle, Aniket; Riener, Robert; Wolf, Peter

    2015-01-01

    Computer games are increasingly being used for training cognitive functions like working memory and attention among the growing population of older adults. While cognitive training games often include elements like difficulty adaptation, rewards, and visual themes to make the games more enjoyable and effective, the effect of different degrees of afforded user control in manipulating these elements has not been systematically studied. To address this issue, two distinct implementations of the three aforementioned game elements were tested among healthy older adults (N = 21, 69.9 ± 6.4 years old) playing a game-like version of the n-back task on a tablet at home for 3 weeks. Two modes were considered, differentiated by the afforded degree of user control of the three elements: user control of difficulty vs. automatic difficulty adaptation, difficulty-dependent rewards vs. automatic feedback messages, and user choice of visual theme vs. no choice. The two modes (“USER-CONTROL” and “AUTO”) were compared for frequency of play, duration of play, and in-game performance. Participants were free to play the game whenever and for however long they wished. Participants in USER-CONTROL exhibited significantly higher frequency of playing, total play duration, and in-game performance than participants in AUTO. The results of the present study demonstrate the efficacy of providing user control in the three game elements, while validating a home-based study design in which participants were not bound by any training regimen, and could play the game whenever they wished. The results have implications for designing cognitive training games that elicit higher compliance and better in-game performance, with an emphasis on home-based training. PMID:26635681

  15. High performance sapphire windows

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.; Liou, Larry

    1993-01-01

    High-quality, wide-aperture optical access is usually required for the advanced laser diagnostics that can now make a wide variety of non-intrusive measurements of combustion processes. Specially processed and mounted sapphire windows are proposed to provide this optical access to extreme environment. Through surface treatments and proper thermal stress design, single crystal sapphire can be a mechanically equivalent replacement for high strength steel. A prototype sapphire window and mounting system have been developed in a successful NASA SBIR Phase 1 project. A large and reliable increase in sapphire design strength (as much as 10x) has been achieved, and the initial specifications necessary for these gains have been defined. Failure testing of small windows has conclusively demonstrated the increased sapphire strength, indicating that a nearly flawless surface polish is the primary cause of strengthening, while an unusual mounting arrangement also significantly contributes to a larger effective strength. Phase 2 work will complete specification and demonstration of these windows, and will fabricate a set for use at NASA. The enhanced capabilities of these high performance sapphire windows will lead to many diagnostic capabilities not previously possible, as well as new applications for sapphire.

  16. Interface-designed Membranes with Shape-controlled Patterns for High-performance Polymer Electrolyte Membrane Fuel Cells

    NASA Astrophysics Data System (ADS)

    Jeon, Yukwon; Kim, Dong Jun; Koh, Jong Kwan; Ji, Yunseong; Kim, Jong Hak; Shul, Yong-Gun

    2015-11-01

    Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method. The best MEA performance is achieved using patterned Nafion membrane with a circle 2 μm in size, which exhibited a very high power density of 1906 mW/cm2 at 75 °C and Pt loading of 0.4 mg/cm2 with 73% improvement compared to the commercial membrane. The improved performance are attributed to the decreased MEA resistances and increased surface area for higher Pt utilization of over 80%. From these enhanced properties, it is possible to operate at lower Pt loading of 0.2 mg/cm2 with an outstanding performance of 1555 mW/cm2 and even at air/low humidity operations.

  17. Interface-designed Membranes with Shape-controlled Patterns for High-performance Polymer Electrolyte Membrane Fuel Cells.

    PubMed

    Jeon, Yukwon; Kim, Dong Jun; Koh, Jong Kwan; Ji, Yunseong; Kim, Jong Hak; Shul, Yong-Gun

    2015-11-10

    Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method. The best MEA performance is achieved using patterned Nafion membrane with a circle 2 μm in size, which exhibited a very high power density of 1906 mW/cm(2) at 75 °C and Pt loading of 0.4 mg/cm(2) with 73% improvement compared to the commercial membrane. The improved performance are attributed to the decreased MEA resistances and increased surface area for higher Pt utilization of over 80%. From these enhanced properties, it is possible to operate at lower Pt loading of 0.2 mg/cm(2) with an outstanding performance of 1555 mW/cm(2) and even at air/low humidity operations.

  18. Interface-designed Membranes with Shape-controlled Patterns for High-performance Polymer Electrolyte Membrane Fuel Cells

    PubMed Central

    Jeon, Yukwon; Kim, Dong Jun; Koh, Jong Kwan; Ji, Yunseong; Kim, Jong Hak; Shul, Yong-Gun

    2015-01-01

    Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method. The best MEA performance is achieved using patterned Nafion membrane with a circle 2 μm in size, which exhibited a very high power density of 1906 mW/cm2 at 75 °C and Pt loading of 0.4 mg/cm2 with 73% improvement compared to the commercial membrane. The improved performance are attributed to the decreased MEA resistances and increased surface area for higher Pt utilization of over 80%. From these enhanced properties, it is possible to operate at lower Pt loading of 0.2 mg/cm2 with an outstanding performance of 1555 mW/cm2 and even at air/low humidity operations. PMID:26552839

  19. High Performance Network Monitoring

    SciTech Connect

    Martinez, Jesse E

    2012-08-10

    Network Monitoring requires a substantial use of data and error analysis to overcome issues with clusters. Zenoss and Splunk help to monitor system log messages that are reporting issues about the clusters to monitoring services. Infiniband infrastructure on a number of clusters upgraded to ibmon2. ibmon2 requires different filters to report errors to system administrators. Focus for this summer is to: (1) Implement ibmon2 filters on monitoring boxes to report system errors to system administrators using Zenoss and Splunk; (2) Modify and improve scripts for monitoring and administrative usage; (3) Learn more about networks including services and maintenance for high performance computing systems; and (4) Gain a life experience working with professionals under real world situations. Filters were created to account for clusters running ibmon2 v1.0.0-1 10 Filters currently implemented for ibmon2 using Python. Filters look for threshold of port counters. Over certain counts, filters report errors to on-call system administrators and modifies grid to show local host with issue.

  20. Controllable synthesis of Cu-doped CoO hierarchical structure for high performance lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Chen, Chengcheng; Huang, Yanan; Zhang, Hao; Wang, Xiaofeng; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2016-05-01

    We report on the strategy of Cu doping inducing the nanosize effect of CoO and their application as anode for lithium ion batteries. With an increase of Cu-doped amount, the structures and morphologies of CoO have special changes. The 0.05 mol Cu-doped CoO shows straw-like bundle structure assembled by nanorods, and the nanorods consist of ultra small nanoparticles (about 6-8 nm). Meanwhile, it shows an excellent rates performance and cycle life. The capacity of 800 mA h g-1 is obtained at 0.5 C after 80 cycles. The highest discharge capacity is 580 mA h g-1 at 10 C and the discharge capacities are relatively stable for 1000 cycles as an anode for Li-ion battery. Therefore, the controllable Cu-doped CoO composite could be deemed to be a potential candidate as an anode material.

  1. Phase-controlled synthesis of α-NiS nanoparticles confined in carbon nanorods for High Performance Supercapacitors

    PubMed Central

    Sun, Chencheng; Ma, Mingze; Yang, Jun; Zhang, Yufei; Chen, Peng; Huang, Wei; Dong, Xiaochen

    2014-01-01

    A facile and phase-controlled synthesis of α-NiS nanoparticles (NPs) embedded in carbon nanorods (CRs) is reported by in-situ sulfurating the preformed Ni/CRs. The nanopore confinement by the carbon matrix is essential for the formation of α-NiS and preventing its transition to β-phase, which is in strong contrast to large aggregated β-NiS particles grown freely without the confinement of CRs. When used as electrochemical electrode, the hybrid electrochemical charge storage of the ultrasmall α-NiS nanoparticels dispersed in CRs is benefit for the high capacitor (1092, 946, 835, 740 F g−1 at current densities of 1, 2, 5, 10 A g−1, respectively.). While the high electrochemical stability (approximately 100% retention of specific capacitance after 2000 charge/discharge cycles) is attributed to the supercapacitor-battery electrode, which makes synergistic effect of capacitor (CRs) and battery (NiS NPs) components rather than a merely additive composite. This work not only suggests a general approach for phase-controlled synthesis of nickel sulfide but also opens the door to the rational design and fabrication of novel nickel-based/carbon hybrid supercapacitor-battery electrode materials. PMID:25394517

  2. Phase-controlled synthesis of α-NiS nanoparticles confined in carbon nanorods for High Performance Supercapacitors

    NASA Astrophysics Data System (ADS)

    Sun, Chencheng; Ma, Mingze; Yang, Jun; Zhang, Yufei; Chen, Peng; Huang, Wei; Dong, Xiaochen

    2014-11-01

    A facile and phase-controlled synthesis of α-NiS nanoparticles (NPs) embedded in carbon nanorods (CRs) is reported by in-situ sulfurating the preformed Ni/CRs. The nanopore confinement by the carbon matrix is essential for the formation of α-NiS and preventing its transition to β-phase, which is in strong contrast to large aggregated β-NiS particles grown freely without the confinement of CRs. When used as electrochemical electrode, the hybrid electrochemical charge storage of the ultrasmall α-NiS nanoparticels dispersed in CRs is benefit for the high capacitor (1092, 946, 835, 740 F g-1 at current densities of 1, 2, 5, 10 A g-1, respectively.). While the high electrochemical stability (approximately 100% retention of specific capacitance after 2000 charge/discharge cycles) is attributed to the supercapacitor-battery electrode, which makes synergistic effect of capacitor (CRs) and battery (NiS NPs) components rather than a merely additive composite. This work not only suggests a general approach for phase-controlled synthesis of nickel sulfide but also opens the door to the rational design and fabrication of novel nickel-based/carbon hybrid supercapacitor-battery electrode materials.

  3. Phase-controlled synthesis of α-NiS nanoparticles confined in carbon nanorods for high performance supercapacitors.

    PubMed

    Sun, Chencheng; Ma, Mingze; Yang, Jun; Zhang, Yufei; Chen, Peng; Huang, Wei; Dong, Xiaochen

    2014-01-01

    A facile and phase-controlled synthesis of α-NiS nanoparticles (NPs) embedded in carbon nanorods (CRs) is reported by in-situ sulfurating the preformed Ni/CRs. The nanopore confinement by the carbon matrix is essential for the formation of α-NiS and preventing its transition to β-phase, which is in strong contrast to large aggregated β-NiS particles grown freely without the confinement of CRs. When used as electrochemical electrode, the hybrid electrochemical charge storage of the ultrasmall α-NiS nanoparticels dispersed in CRs is benefit for the high capacitor (1092, 946, 835, 740 F g(-1) at current densities of 1, 2, 5, 10 A g(-1), respectively.). While the high electrochemical stability (approximately 100% retention of specific capacitance after 2000 charge/discharge cycles) is attributed to the supercapacitor-battery electrode, which makes synergistic effect of capacitor (CRs) and battery (NiS NPs) components rather than a merely additive composite. This work not only suggests a general approach for phase-controlled synthesis of nickel sulfide but also opens the door to the rational design and fabrication of novel nickel-based/carbon hybrid supercapacitor-battery electrode materials. PMID:25394517

  4. High-performance n-type black phosphorus transistors with type control via thickness and contact-metal engineering

    PubMed Central

    Perello, David J.; Chae, Sang Hoon; Song, Seunghyun; Lee, Young Hee

    2015-01-01

    Recent work has demonstrated excellent p-type field-effect switching in exfoliated black phosphorus, but type control has remained elusive. Here, we report unipolar n-type black phosphorus transistors with switching polarity control via contact-metal engineering and flake thickness, combined with oxygen and moisture-free fabrication. With aluminium contacts to black phosphorus, a unipolar to ambipolar transition occurs as flake thickness increases from 3 to 13 nm. The 13-nm aluminium-contacted flake displays graphene-like symmetric hole and electron mobilities up to 950 cm2 V−1 s−1 at 300 K, while a 3 nm flake displays unipolar n-type switching with on/off ratios greater than 105 (107) and electron mobility of 275 (630) cm2 V−1 s−1 at 300 K (80 K). For palladium contacts, p-type behaviour dominates in thick flakes, while 2.5–7 nm flakes have symmetric ambipolar transport. These results demonstrate a leap in n-type performance and exemplify the logical switching capabilities of black phosphorus. PMID:26223778

  5. Ordered Monolayer Gold Nano-urchin Structures and Their Size Induced Control for High Gas Sensing Performance

    NASA Astrophysics Data System (ADS)

    Sabri, Ylias M.; Kandjani, Ahmad Esmaielzadeh; Ippolito, Samuel J.; Bhargava, Suresh K.

    2016-04-01

    The synthesis of ordered monolayers of gold nano-urchin (Au-NU) nanostructures with controlled size, directly on thin films using a simple electrochemical method is reported in this study. In order to demonstrate one of the vast potential applications, the developed Au-NUs were formed on the electrodes of transducers (QCM) to selectively detect low concentrations of elemental mercury (Hg0) vapor. It was found that the sensitivity and selectivity of the sensor device is enhanced by increasing the size of the nanospikes on the Au-NUs. The Au-NU-12 min QCM (Au-NUs with nanospikes grown on it for a period of 12 min) had the best performance in terms of transducer based Hg0 vapor detection. The sensor had 98% accuracy, 92% recovery, 96% precision (repeatability) and significantly, showed the highest sensitivity reported to date, resulting in a limit of detection (LoD) of only 32 μg/m3 at 75 °C. When compared to the control counterpart, the accuracy and sensitivity of the Au-NU-12 min was enhanced by ~2 and ~5 times, respectively. The results demonstrate the excellent activity of the developed materials which can be applied to a range of applications due to their long range order, tunable size and ability to form directly on thin-films.

  6. High-performance n-type black phosphorus transistors with type control via thickness and contact-metal engineering.

    PubMed

    Perello, David J; Chae, Sang Hoon; Song, Seunghyun; Lee, Young Hee

    2015-07-30

    Recent work has demonstrated excellent p-type field-effect switching in exfoliated black phosphorus, but type control has remained elusive. Here, we report unipolar n-type black phosphorus transistors with switching polarity control via contact-metal engineering and flake thickness, combined with oxygen and moisture-free fabrication. With aluminium contacts to black phosphorus, a unipolar to ambipolar transition occurs as flake thickness increases from 3 to 13 nm. The 13-nm aluminium-contacted flake displays graphene-like symmetric hole and electron mobilities up to 950 cm(2) V(-1) s(-1) at 300 K, while a 3 nm flake displays unipolar n-type switching with on/off ratios greater than 10(5) (10(7)) and electron mobility of 275 (630) cm(2) V(-1) s(-1) at 300 K (80 K). For palladium contacts, p-type behaviour dominates in thick flakes, while 2.5-7 nm flakes have symmetric ambipolar transport. These results demonstrate a leap in n-type performance and exemplify the logical switching capabilities of black phosphorus.

  7. Ordered Monolayer Gold Nano-urchin Structures and Their Size Induced Control for High Gas Sensing Performance

    PubMed Central

    Sabri, Ylias M.; Kandjani, Ahmad Esmaielzadeh; Ippolito, Samuel J.; Bhargava, Suresh K.

    2016-01-01

    The synthesis of ordered monolayers of gold nano-urchin (Au-NU) nanostructures with controlled size, directly on thin films using a simple electrochemical method is reported in this study. In order to demonstrate one of the vast potential applications, the developed Au-NUs were formed on the electrodes of transducers (QCM) to selectively detect low concentrations of elemental mercury (Hg0) vapor. It was found that the sensitivity and selectivity of the sensor device is enhanced by increasing the size of the nanospikes on the Au-NUs. The Au-NU-12 min QCM (Au-NUs with nanospikes grown on it for a period of 12 min) had the best performance in terms of transducer based Hg0 vapor detection. The sensor had 98% accuracy, 92% recovery, 96% precision (repeatability) and significantly, showed the highest sensitivity reported to date, resulting in a limit of detection (LoD) of only 32 μg/m3 at 75 °C. When compared to the control counterpart, the accuracy and sensitivity of the Au-NU-12 min was enhanced by ~2 and ~5 times, respectively. The results demonstrate the excellent activity of the developed materials which can be applied to a range of applications due to their long range order, tunable size and ability to form directly on thin-films. PMID:27090570

  8. Ordered Monolayer Gold Nano-urchin Structures and Their Size Induced Control for High Gas Sensing Performance.

    PubMed

    Sabri, Ylias M; Kandjani, Ahmad Esmaielzadeh; Ippolito, Samuel J; Bhargava, Suresh K

    2016-01-01

    The synthesis of ordered monolayers of gold nano-urchin (Au-NU) nanostructures with controlled size, directly on thin films using a simple electrochemical method is reported in this study. In order to demonstrate one of the vast potential applications, the developed Au-NUs were formed on the electrodes of transducers (QCM) to selectively detect low concentrations of elemental mercury (Hg(0)) vapor. It was found that the sensitivity and selectivity of the sensor device is enhanced by increasing the size of the nanospikes on the Au-NUs. The Au-NU-12 min QCM (Au-NUs with nanospikes grown on it for a period of 12 min) had the best performance in terms of transducer based Hg(0) vapor detection. The sensor had 98% accuracy, 92% recovery, 96% precision (repeatability) and significantly, showed the highest sensitivity reported to date, resulting in a limit of detection (LoD) of only 32 μg/m3 at 75 °C. When compared to the control counterpart, the accuracy and sensitivity of the Au-NU-12 min was enhanced by ~2 and ~5 times, respectively. The results demonstrate the excellent activity of the developed materials which can be applied to a range of applications due to their long range order, tunable size and ability to form directly on thin-films. PMID:27090570

  9. Commoditization of High Performance Storage

    SciTech Connect

    Studham, Scott S.

    2004-04-01

    The commoditization of high performance computers started in the late 80s with the attack of the killer micros. Previously, high performance computers were exotic vector systems that could only be afforded by an illustrious few. Now everyone has a supercomputer composed of clusters of commodity processors. A similar commoditization of high performance storage has begun. Commodity disks are being used for high performance storage, enabling a paradigm change in storage and significantly changing the price point of high volume storage.

  10. High Performance Computing Today

    SciTech Connect

    Dongarra, Jack; Meuer,Hans; Simon,Horst D.; Strohmaier,Erich

    2000-04-01

    In last 50 years, the field of scientific computing has seen a rapid change of vendors, architectures, technologies and the usage of systems. Despite all these changes the evolution of performance on a large scale however seems to be a very steady and continuous process. Moore's Law is often cited in this context. If the authors plot the peak performance of various computers of the last 5 decades in Figure 1 that could have been called the supercomputers of their time they indeed see how well this law holds for almost the complete lifespan of modern computing. On average they see an increase in performance of two magnitudes of order every decade.

  11. Controlled growth of conical nickel oxide nanocrystals and their high performance gas sensing devices for ammonia molecule detection.

    PubMed

    Wang, Jian; Yang, Fan; Wei, Xiaowei; Zhang, Yafei; Wei, Liangming; Zhang, Jianjun; Tang, Qifeng; Guo, Biao; Xu, Lei

    2014-08-21

    NiO nanocones with good symmetry and highly ordered structure on NiO foil substrate have been successfully fabricated via a facile wet chemical approach combined with subsequent high temperature oxidation. These organized conical superstructures grow only along a certain direction and be controlled via the self-assembly and oriented attachment of a nucleus, which mainly rely on the similar surface energies and the extent of lattice matching of the oriented attached surfaces. During high temperature oxidation, the electric field created via the Ni(2+) and O(2-) facilitates Ni(2+) diffusion outward along the grain boundaries and O(2-) diffusion inward toward to meet the Ni(2+) ions, forming NiO. The as-grown NiO nanocones are 50-350 nm in diameter and 50-400 nm in height. The tip diameter of the nanocone is about 30 nm and the apex angle of the nanocone is about 40°. Meanwhile, we systematically investigated the gas sensing properties of the sensors based on the as-fabricated NiO foil covered with nanocone arrays for ammonia detection at room temperature. The results show that the gas sensing devices have outstanding sensitivity, reproducibility and selectivity, which are mainly because of the excellent connection between the NiO sensing materials and the Au electrodes, the strong electron donating ability of ammonia and the large active surface of selective physisorption for ammonia.

  12. High Performance Parallel Computational Nanotechnology

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Craw, James M. (Technical Monitor)

    1995-01-01

    control mini robotic manipulators for positional control; scalable numerical algorithms for reliability, verifications and testability. There appears no fundamental obstacle to simulating molecular compilers and molecular computers on high performance parallel computers, just as the Boeing 777 was simulated on a computer before manufacturing it.

  13. Numerical Stability and Control Analysis Towards Falling-Leaf Prediction Capabilities of Splitflow for Two Generic High-Performance Aircraft Models

    NASA Technical Reports Server (NTRS)

    Charlton, Eric F.

    1998-01-01

    Aerodynamic analysis are performed using the Lockheed-Martin Tactical Aircraft Systems (LMTAS) Splitflow computational fluid dynamics code to investigate the computational prediction capabilities for vortex-dominated flow fields of two different tailless aircraft models at large angles of attack and sideslip. These computations are performed with the goal of providing useful stability and control data to designers of high performance aircraft. Appropriate metrics for accuracy, time, and ease of use are determined in consultations with both the LMTAS Advanced Design and Stability and Control groups. Results are obtained and compared to wind-tunnel data for all six components of forces and moments. Moment data is combined to form a "falling leaf" stability analysis. Finally, a handful of viscous simulations were also performed to further investigate nonlinearities and possible viscous effects in the differences between the accumulated inviscid computational and experimental data.

  14. Graphene oxide as a high-performance fluid-loss-control additive in water-based drilling fluids.

    PubMed

    Kosynkin, Dmitry V; Ceriotti, Gabriel; Wilson, Kurt C; Lomeda, Jay R; Scorsone, Jason T; Patel, Arvind D; Friedheim, James E; Tour, James M

    2012-01-01

    Graphene oxide (GO) performs well as a filtration additive in water-based drilling fluids at concentrations as low as 0.2 % (w/w) by carbon content. Standard American Petroleum Institute (API) filtration tests were conducted on pH-adjusted, aqueous dispersions of GO and xanthan gum. It was found that a combination of large-flake GO and powdered GO in a 3:1 ratio performed best in the API tests, allowing an average fluid loss of 6.1 mL over 30 min and leaving a filter cake ~20 μm thick. In comparison, a standard suspension (~12 g/L) of clays and polymers used in the oil industry gave an average fluid loss of 7.2 mL and a filter cake ~280 μm thick. Scanning electron microscopy imaging revealed the extreme pliability of well-exfoliated GO, as the pressure due to filtration crumpled single GO sheets, forcing them to slide through pores with diameters much smaller than the flake's flattened size. GO solutions also exhibited greater shear thinning and higher temperature stability compared to clay-based fluid-loss additives, demonstrating potential for high-temperature well applications.

  15. Graphene oxide as a high-performance fluid-loss-control additive in water-based drilling fluids.

    PubMed

    Kosynkin, Dmitry V; Ceriotti, Gabriel; Wilson, Kurt C; Lomeda, Jay R; Scorsone, Jason T; Patel, Arvind D; Friedheim, James E; Tour, James M

    2012-01-01

    Graphene oxide (GO) performs well as a filtration additive in water-based drilling fluids at concentrations as low as 0.2 % (w/w) by carbon content. Standard American Petroleum Institute (API) filtration tests were conducted on pH-adjusted, aqueous dispersions of GO and xanthan gum. It was found that a combination of large-flake GO and powdered GO in a 3:1 ratio performed best in the API tests, allowing an average fluid loss of 6.1 mL over 30 min and leaving a filter cake ~20 μm thick. In comparison, a standard suspension (~12 g/L) of clays and polymers used in the oil industry gave an average fluid loss of 7.2 mL and a filter cake ~280 μm thick. Scanning electron microscopy imaging revealed the extreme pliability of well-exfoliated GO, as the pressure due to filtration crumpled single GO sheets, forcing them to slide through pores with diameters much smaller than the flake's flattened size. GO solutions also exhibited greater shear thinning and higher temperature stability compared to clay-based fluid-loss additives, demonstrating potential for high-temperature well applications. PMID:22136134

  16. Helicopter high gain control

    NASA Technical Reports Server (NTRS)

    Cunningham, T. B.; Nunn, E. C.

    1979-01-01

    High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.

  17. Controllable synthesis of Cu-doped CoO hierarchical structure for high performance lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Chen, Chengcheng; Huang, Yanan; Zhang, Hao; Wang, Xiaofeng; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2016-05-01

    We report on the strategy of Cu doping inducing the nanosize effect of CoO and their application as anode for lithium ion batteries. With an increase of Cu-doped amount, the structures and morphologies of CoO have special changes. The 0.05 mol Cu-doped CoO shows straw-like bundle structure assembled by nanorods, and the nanorods consist of ultra small nanoparticles (about 6-8 nm). Meanwhile, it shows an excellent rates performance and cycle life. The capacity of 800 mA h g-1 is obtained at 0.5 C after 80 cycles. The highest discharge capacity is 580 mA h g-1 at 10 C and the discharge capacities are relatively stable for 1000 cycles as an anode for Li-ion battery. Therefore, the controllable Cu-doped CoO composite could be deemed to be a potential candidate as an anode material.

  18. High Performance Arcjet Engines

    NASA Technical Reports Server (NTRS)

    Kennel, Elliot B.; Ivanov, Alexey Nikolayevich; Nikolayev, Yuri Vyacheslavovich

    1994-01-01

    This effort sought to exploit advanced single crystal tungsten-tantalum alloy material for fabrication of a high strength, high temperature arcjet anode. The use of this material is expected to result in improved strength, temperature resistance, and lifetime compared to state of the art polycrystalline alloys. In addition, the use of high electrical and thermal conductivity carbon-carbon composites was considered, and is believed to be a feasible approach. Highly conductive carbon-carbon composite anode capability represents enabling technology for rotating-arc designs derived from the Russian Scientific Research Institute of Thermal Processes (NIITP) because of high heat fluxes at the anode surface. However, for US designs the anode heat flux is much smaller, and thus the benefits are not as great as in the case of NIITP-derived designs. Still, it does appear that the tensile properties of carbon-carbon can be even better than those of single crystal tungsten alloys, especially when nearly-single-crystal fibers such as vapor grown carbon fiber (VGCF) are used. Composites fabricated from such materials must be coated with a refractory carbide coating in order to ensure compatibility with high temperature hydrogen. Fabrication of tungsten alloy single crystals in the sizes required for fabrication of an arcjet anode has been shown to be feasible. Test data indicate that the material can be expected to be at least the equal of W-Re-HfC polycrystalline alloy in terms of its tensile properties, and possibly superior. We are also informed by our colleagues at Scientific Production Association Luch (NP0 Luch) that it is possible to use Russian technology to fabricate polycrystalline W-Re-HfC or other high strength alloys if desired. This is important because existing engines must rely on previously accumulated stocks of these materials, and a fabrication capability for future requirements is not assured.

  19. High performance cyclone development

    SciTech Connect

    Giles, W.B.

    1981-01-01

    The results of cold flow experiments at atmospheric conditions of an air-shielded 18 in-dia electrocyclone with a central cusped electrode are reported using fine test dusts of both flyash and nickel powder. These results are found to confirm expectations of enhanced performance, similar to earlier work on a 12 in-dia model. An analysis of the combined inertial-electrostatic force field is also presented which identifies general design goals and scaling laws. From this, it is found that electrostatic enhancement will be particularly beneficial for fine dusts in large cyclones. Recommendations for further improvement in cyclone collection efficiency are proposed.

  20. Controllable in situ synthesis of epsilon manganese dioxide hollow structure/RGO nanocomposites for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Lin, Mei; Chen, Bolei; Wu, Xiao; Qian, Jiasheng; Fei, Linfeng; Lu, Wei; Chan, Lai Wa Helen; Yuan, Jikang

    2016-01-01

    Well-organized epsilon-MnO2 hollow spheres/reduced graphene oxide (MnO2HS/RGO) composites have been successfully constructed via a facile and one-pot synthetic route. The ε-MnO2 hollow spheres with the diameter of ~500 nm were grown in situ with homogeneous distribution on both sides of graphene oxide (GO) sheets in aqueous suspensions. The formation mechanism of the MnO2HS/RGO composites has been systematically investigated, and a high specific capacitance and good cycling capability were achieved on using the composites as supercapacitors. The galvanostatic charge/discharge curves show a specific capacitance of 471.5 F g-1 at 0.8 A g-1. The hollow structures of ε-MnO2 and the crumpled RGO sheets can enhance the electroactive surface area and improve the electrical conductivity, thus further facilitating the charge transport. The MnO2HS/RGO composite exhibits a high capacitance of 272 F g-1 at 3 A g-1 (92% retention) even after 1000 cycles. The prominent electrochemical performance might be attributed to the combination of the pseudo-capacitance of the MnO2 nanospheres with a hollow structure and to the good electrical conductivity of the RGO sheets. This work explores a new concept in designing metal oxides/RGO composites as electrode materials.Well-organized epsilon-MnO2 hollow spheres/reduced graphene oxide (MnO2HS/RGO) composites have been successfully constructed via a facile and one-pot synthetic route. The ε-MnO2 hollow spheres with the diameter of ~500 nm were grown in situ with homogeneous distribution on both sides of graphene oxide (GO) sheets in aqueous suspensions. The formation mechanism of the MnO2HS/RGO composites has been systematically investigated, and a high specific capacitance and good cycling capability were achieved on using the composites as supercapacitors. The galvanostatic charge/discharge curves show a specific capacitance of 471.5 F g-1 at 0.8 A g-1. The hollow structures of ε-MnO2 and the crumpled RGO sheets can enhance the

  1. Effect of the fused quartz particle density on nucleation and grain control of high-performance multicrystalline silicon ingots

    NASA Astrophysics Data System (ADS)

    Ding, Junjing; Yu, Yunyang; Chen, Wenliang; Zhou, Xucheng; Wu, Zhiyong; Zhong, Genxiang; Huang, Xinming

    2016-11-01

    The nucleation process of high-performance multicrystalline silicon (HP mc-Si) growth seeded by fused quartz particles (FQP) through directional solidification is crucial for the ingot quality. To determine the optimal density of FQP and obtain a better nucleation process and the grain growth, we cast ingots using four different densities of FQP fixed on the bottom of the four quartz crucibles and covered them with a certain thickness of Si3N4 coating. FQP sizes of 30-50 mesh were used, and the influence of the fused quartz particle density on the nucleation mechanism, initial grain uniformity, grain size, density of dislocation clusters, and cell efficiency were analyzed. Compared with the ingots seeded with other three densities of FQP, the 220 particles/cm2 of FQP seeded ingot showed better uniformity of nucleation and initial grains. A large number of small uniform Si grains with lower density of dislocation clusters in the bottom of the ingot were observed. The average conversion efficiency of p-type solar cells manufactured with the 220 particles/cm2 seeded ingot (18.28%) was 0.19% higher than that manufactured with the 120 particles/cm2 seeded ingot (18.09%).

  2. ACCESS: Detector Control and Performance

    NASA Astrophysics Data System (ADS)

    Morris, Matthew J.; Kaiser, M.; McCandliss, S. R.; Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Bohlin, R.; Kurucz, R. L.; Riess, A. G.; Pelton, R.; Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Mott, D. B.; Wen, Y.; Benford, D. J.; Gardner, J. P.; Feldman, P. D.; Moos, H. W.; Lampton, M.; Perlmutter, S.; Woodgate, B. E.

    2014-01-01

    ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a series of rocket-borne sub-orbital missions and ground-based experiments that will enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory 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 (companion poster, Kaiser et al.). The flight detector and detector spare have been selected and integrated with their electronics and flight mount. The controller electronics have been flight qualified. Vibration testing to launch loads and thermal vacuum testing of the detector, mount, and housing have been successfully performed. Further improvements to the flight controller housing have been made. A cryogenic ground test system has been built. Dark current and read noise tests have been performed, yielding results consistent with the initial characterization tests of the detector performed by Goddard Space Flight Center’s Detector Characterization Lab (DCL). Detector control software has been developed and implemented for ground testing. Performance and integration of the detector and controller with the flight software will be presented. NASA APRA sounding rocket grant NNX08AI65G supports this work.

  3. High Voltage SPT Performance

    NASA Technical Reports Server (NTRS)

    Manzella, David; Jacobson, David; Jankovsky, Robert

    2001-01-01

    A 2.3 kW stationary plasma thruster designed to operate at high voltage was tested at discharge voltages between 300 and 1250 V. Discharge specific impulses between 1600 and 3700 sec were demonstrated with thrust between 40 and 145 mN. Test data indicated that discharge voltage can be optimized for maximum discharge efficiency. The optimum discharge voltage was between 500 and 700 V for the various anode mass flow rates considered. The effect of operating voltage on optimal magnet field strength was investigated. The effect of cathode flow rate on thruster efficiency was considered for an 800 V discharge.

  4. High performance steam development

    SciTech Connect

    Duffy, T.; Schneider, P.

    1995-10-01

    Over 30 years ago U.S. industry introduced the world`s highest temperature (1200{degrees}F at 5000 psig) and most efficient power plant, the Eddystone coal-burning steam plant. The highest alloy material used in the plant was 316 stainless steel. Problems during the first few years of operation caused a reduction in operating temperature to 1100{degrees}F which has generally become the highest temperature used in plants around the world. Leadership in high temperature steam has moved to Japan and Europe over the last 30 years.

  5. High performance aerated lagoon systems

    SciTech Connect

    Rich, L.

    1999-08-01

    At a time when less money is available for wastewater treatment facilities and there is increased competition for the local tax dollar, regulatory agencies are enforcing stricter effluent limits on treatment discharges. A solution for both municipalities and industry is to use aerated lagoon systems designed to meet these limits. This monograph, prepared by a recognized expert in the field, provides methods for the rational design of a wide variety of high-performance aerated lagoon systems. Such systems range from those that can be depended upon to meet secondary treatment standards alone to those that, with the inclusion of intermittent sand filters or elements of sequenced biological reactor (SBR) technology, can also provide for nitrification and nutrient removal. Considerable emphasis is placed on the use of appropriate performance parameters, and an entire chapter is devoted to diagnosing performance failures. Contents include: principles of microbiological processes, control of algae, benthal stabilization, design for CBOD removal, design for nitrification and denitrification in suspended-growth systems, design for nitrification in attached-growth systems, phosphorus removal, diagnosing performance.

  6. Turning High-Poverty Schools into High-Performing Schools

    ERIC Educational Resources Information Center

    Parrett, William H.; Budge, Kathleen

    2012-01-01

    If some schools can overcome the powerful and pervasive effects of poverty to become high performing, shouldn't any school be able to do the same? Shouldn't we be compelled to learn from those schools? Although schools alone will never systemically eliminate poverty, high-poverty, high-performing (HP/HP) schools take control of what they can to…

  7. Hetero-metal cation control of CuO nanostructures and their high catalytic performance for CO oxidation

    NASA Astrophysics Data System (ADS)

    Huang, Hongwen; Zhang, Liqiang; Wu, Kewei; Yu, Qing; Chen, Ru; Yang, Hangsheng; Peng, Xinsheng; Ye, Zhizhen

    2012-11-01

    A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous CuO quasi-monocrystalline nanosheets prepared at 25 °C with a thickness of ca. 10 nm and large specific surface area of 80.32 m2 g-1 is investigated intensively. These CuO nanosheets demonstrate a superior catalytic activity for CO oxidation, with features of high CO conversion efficiency (47.77 mmolCO g-1CuO h-1 at 200 °C), which is close to that reported for previously investigated supported-CuO catalysts, and a low apparent activation energy Ea (53.3 kJ mol-1).A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous Cu

  8. High Performance Astrophysics Computing

    NASA Astrophysics Data System (ADS)

    Capuzzo-Dolcetta, R.; Arca-Sedda, M.; Mastrobuono-Battisti, A.; Punzo, D.; Spera, M.

    2012-07-01

    The application of high end computing to astrophysical problems, mainly in the galactic environment, is developing for many years at the Dep. of Physics of Sapienza Univ. of Roma. The main scientific topic is the physics of self gravitating systems, whose specific subtopics are: i) celestial mechanics and interplanetary probe transfers in the solar system; ii) dynamics of globular clusters and of globular cluster systems in their parent galaxies; iii) nuclear clusters formation and evolution; iv) massive black hole formation and evolution; v) young star cluster early evolution. In this poster we describe the software and hardware computational resources available in our group and how we are developing both software and hardware to reach the scientific aims above itemized.

  9. Thermal pretreatments of superficially porous silica particles for high-performance liquid chromatography: Surface control, structural characterization and chromatographic evaluation.

    PubMed

    Mignot, Mélanie; Sebban, Muriel; Tchapla, Alain; Mercier, Olivier; Cardinael, Pascal; Peulon-Agasse, Valérie

    2015-11-01

    This study reports the impact of thermal pretreatment between 400 and 1100°C on superficially porous silica particles (e.g. core-shell, fused-core; here abbreviated as SPP silica). The different thermally pretreated SPP silica (400°C, 900°C and 1100°C) were chemically bonded with an octadecyl chain under microwave irradiation. The bare SPP silica, thermally untreated and pretreated, as well as the chemically bonded phases (CBPs) were fully characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and solid state cross polarization magic angle spinning (CP-MAS) (29)Si NMR. The chromatographic properties of the overall set of C18-thermally pretreated SPP silica stationary phases were determined using the Tanaka test. Complementary, the simplified Veuthey test was used to deeply study the silanol activity, considering a set of 7 basic solutes with various physicochemical properties. Both tests were also performed on different commercial SPP silica columns and different types of bonding chemistry (C18, Phenyl-hexyl, RP-amide, C30, aQ). Multivariate data analyses (hierarchical cluster analysis and principal component analysis) were carried out to define groups of stationary phases with similar chromatographic properties and situate them in relation to those commercially available. These different C18-thermally pretreated SPP silicas represented a wide range of stationary phases as they were spread out along the score plot. Moreover, this study highlighted that the thermal pretreatment improved the chemical stability of the SPP silica compare to untreated SPP silica and untreated porous silica. Consequently, higher thermal pretreatment can be applied (up to 900°C) before functionalization without destruction of the silica matrix. Indeed, a significantly lower dissolution of the thermally pretreated SPP silica under aggressive conditions could allow the use of the corresponding functionalized stationary phases at high

  10. CFD simulations of the flow control performance applied for inlet of low drag high-bypass turbofan engine at cross flow regimes

    NASA Astrophysics Data System (ADS)

    Kursakov, I. A.; Kazhan, E. V.; Lysenkov, A. V.; Savelyev, A. A.

    2016-10-01

    Paper describes the optimization procedure for low cruise drag inlet of high-bypass ratio turbofan engine (HBRE). The critical cross-flow velocity when the flow separation on the lee side of the inlet channel occurs is determined. The effciency of different flow control devices used to improve the flow parameters at inlet section cross flow regime is analyzed. Boundary layer suction, bypass slot and vortex generators are considered. It is shown that flow control devices enlarge the stability range of inlet performance at cross flow regimes.

  11. High performance alloy electroforming

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Winkelman, D. M.

    1989-01-01

    Electroformed copper and nickel are used in structural applications for advanced propellant combustion chambers. An improved process has been developed by Bell Aerospace Textron, Inc. wherein electroformed nickel-manganese alloy has demonstrated superior mechanical and thermal stability when compared to previously reported deposits from known nickel plating processes. Solution chemistry and parametric operating procedures are now established and material property data is established for deposition of thick, large complex shapes such as the Space Shuttle Main Engine. The critical operating variables are those governing the ratio of codeposited nickel and manganese. The deposition uniformity which in turn affects the manganese concentration distribution is affected by solution resistance and geometric effects as well as solution agitation. The manganese concentration in the deposit must be between 2000 and 3000 ppm for optimum physical properties to be realized. The study also includes data regarding deposition procedures for achieving excellent bond strength at an interface with copper, nickel-manganese or INCONEL 718. Applications for this electroformed material include fabrication of complex or re-entry shapes which would be difficult or impossible to form from high strength alloys such as INCONEL 718.

  12. Experimental and Numerical Optimization of a High-Lift System to Improve Low-Speed Performance, Stability, and Control of an Arrow-Wing Supersonic Transport

    NASA Technical Reports Server (NTRS)

    Hahne, David E.; Glaab, Louis J.

    1999-01-01

    An investigation was performed to evaluate leading-and trailing-edge flap deflections for optimal aerodynamic performance of a High-Speed Civil Transport concept during takeoff and approach-to-landing conditions. The configuration used for this study was designed by the Douglas Aircraft Company during the 1970's. A 0.1-scale model of this configuration was tested in the Langley 30- by 60-Foot Tunnel with both the original leading-edge flap system and a new leading-edge flap system, which was designed with modem computational flow analysis and optimization tools. Leading-and trailing-edge flap deflections were generated for the original and modified leading-edge flap systems with the computational flow analysis and optimization tools. Although wind tunnel data indicated improvements in aerodynamic performance for the analytically derived flap deflections for both leading-edge flap systems, perturbations of the analytically derived leading-edge flap deflections yielded significant additional improvements in aerodynamic performance. In addition to the aerodynamic performance optimization testing, stability and control data were also obtained. An evaluation of the crosswind landing capability of the aircraft configuration revealed that insufficient lateral control existed as a result of high levels of lateral stability. Deflection of the leading-and trailing-edge flaps improved the crosswind landing capability of the vehicle considerably; however, additional improvements are required.

  13. High Stability Engine Control (HISTEC)

    NASA Technical Reports Server (NTRS)

    DeLaat, John C.; Southwick, Robert D.; Gallops, George W.

    1996-01-01

    Future aircraft turbine engines, both commercial and military, must be able to successfully accommodate expected increased levels of steady-state and dynamic engine-face distortion. The current approach of incorporating a sufficient component design stall margin to tolerate these increased levels of distortion would significantly reduce performance. The objective of the High Stability Engine Control (HISTEC) program is to design, develop, and flight demonstrate an advanced, high-stability, integrated engine control system that uses measurement-based, real-time estimates of distortion to enhance engine stability. The resulting distortion tolerant control reduces the required design stall margin, with a corresponding increase in performance and decrease in fuel burn. The HISTEC concept, consisting of a Distortion Estimation System and a Stability Management Control, has been designed and developed. The Distortion Estimation System uses a small number of high-response pressure sensors at the engine face to calculate indicators of the type and extent of distortion in real time. The Stability Management Control, through direct control of the fan and compressor pressure ratio, accommodates the distortion by transiently increasing the amount of stall margin available based on information from the Distortion Estimation System. Simulation studies have shown the HISTEC distortion tolerant control is able to successfully estimate and accommodate time-varying distortion. Currently, hardware and software systems necessary for flight demonstration of the HISTEC concept are being designed and developed. The HISTEC concept will be flight tested in early 1997.

  14. High Performance Perovskite Solar Cells

    PubMed Central

    Tong, Xin; Lin, Feng; Wu, Jiang

    2015-01-01

    Perovskite solar cells fabricated from organometal halide light harvesters have captured significant attention due to their tremendously low device costs as well as unprecedented rapid progress on power conversion efficiency (PCE). A certified PCE of 20.1% was achieved in late 2014 following the first study of long‐term stable all‐solid‐state perovskite solar cell with a PCE of 9.7% in 2012, showing their promising potential towards future cost‐effective and high performance solar cells. Here, notable achievements of primary device configuration involving perovskite layer, hole‐transporting materials (HTMs) and electron‐transporting materials (ETMs) are reviewed. Numerous strategies for enhancing photovoltaic parameters of perovskite solar cells, including morphology and crystallization control of perovskite layer, HTMs design and ETMs modifications are discussed in detail. In addition, perovskite solar cells outside of HTMs and ETMs are mentioned as well, providing guidelines for further simplification of device processing and hence cost reduction.

  15. Cost Control Strategies for Zero Energy Buildings: High-Performance Design and Construction on a Budget (Brochure)

    SciTech Connect

    Not Available

    2014-09-01

    There is mounting evidence that zero energy can, in many cases, be achieved within typical construction budgets. To ensure that the momentum behind zero energy buildings and other low-energy buildings will continue to grow, this guide assembles recommendations for replicating specific successes of early adopters who have met their energy goals while controlling costs. Contents include: discussion of recommended cost control strategies, which are grouped by project phase (acquisition and delivery, design, and construction) and accompanied by industry examples; recommendations for balancing key decision-making factors; and quick reference tables that can help teams apply strategies to specific projects.

  16. Multi-analyte high performance liquid chromatography coupled to high resolution tandem mass spectrometry method for control of pesticide residues, mycotoxins, and pyrrolizidine alkaloids.

    PubMed

    Dzuman, Zbynek; Zachariasova, Milena; Veprikova, Zdenka; Godula, Michal; Hajslova, Jana

    2015-03-10

    A new reliable and highly sensitive method based on high performance liquid chromatographic (HPLC) separation and high resolution tandem mass spectrometric detection (HRMS/MS) has been developed and validated for determination of 323 pesticide residues, 55 mycotoxins, and 11 plant toxins represented by pyrrolizidine alkaloids. The method was validated for three matrices, leek, wheat, and tea differing in nature/amount of co-extracts that may cause various matrix effects. For target analytes isolation, optimized QuEChERS-based (quick, easy, cheap, effective, rugged, and safe) extraction procedure was employed. Spectral HRMS/MS library has been established providing an entire spectrum of fragment ions for each analyte, which allows unbiased identification and confirmation of target compounds. The limits of quantification (LOQs) of target analytes were below 10 μg kg(-1) for 82%, 81%, and 61% for matrices leek, wheat, and tea, respectively. Recoveries were in the acceptable range (70-120%) according to SANCO/12571/2013 for most of target analytes, except for highly polar 'masked' mycotoxin deoxynivalenol-3-glucoside with recoveries 35%, 47%, and 42% for matrices leek, wheat, and tea, respectively. The linearities of calibration curves expressed as coefficients of determination were in the range of 0.9661-1.000, and repeatabilities expressed as relative standard deviations (RSDs) at LOQs lied in the range of 0.25-13.51%. The trueness of the method was verified using several certified reference materials (CRMs) and proficiency test samples.

  17. High Performance Thin Layer Chromatography.

    ERIC Educational Resources Information Center

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  18. Yoga Improves Academic Performance in Urban High School Students Compared to Physical Education: A Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Hagins, Marshall; Rundle, Andrew

    2016-01-01

    Yoga programs within schools have become more widespread but research regarding the potential effect on academic achievement remains limited. This study cluster-randomized 112 students within a single New York City public high school to participate in either school-based yoga or physical education (PE) for an entire academic year. The primary…

  19. Study and Simulation of Enhancements for TCP (Transmission Control Protocol) Performance Over Noisy, High-Latency Links

    NASA Technical Reports Server (NTRS)

    Shepard, Timothy J.; Partridge, Craig; Coulter, Robert

    1997-01-01

    The designers of the TCP/IP protocol suite explicitly included support of satellites in their design goals. The goal of the Internet Project was to design a protocol which could be layered over different networking technologies to allow them to be concatenated into an internet. The results of this project included two protocols, IP and TCP. IP is the protocol used by all elements in the network and it defines the standard packet format for IP datagrams. TCP is the end-to-end transport protocol commonly used between end systems on the Internet to derive a reliable bi-directional byte-pipe service from the underlying unreliable IP datagram service. Satellite links are explicitly mentioned in Vint Cerf's 2-page article which appeared in 1980 in CCR [2] to introduce the specifications for IP and TCP. In the past fifteen years, TCP has been demonstrated to work over many differing networking technologies, including over paths including satellites links. So if satellite links were in the minds of the designers from the beginning, what is the problem? The problem is that the performance of TCP has in some cases been disappointing. A goal of the authors of the original specification of TCP was to specify only enough behavior to ensure interoperability. The specification left a number of important decisions, in particular how much data is to be sent when, to the implementor. This was deliberately' done. By leaving performance-related decisions to the implementor, this would allow the protocol TCP to be tuned and adapted to different networks and situations in the future without the need to revise the specification of the protocol, or break interoperability. Interoperability would continue while future implementations would be allowed flexibility to adapt to needs which could not be anticipated at the time of the original protocol design.

  20. High power ion thruster performance

    NASA Technical Reports Server (NTRS)

    Rawlin, Vincent K.; Patterson, Michael J.

    1987-01-01

    The ion thruster is one of several forms of space electric propulsion being considered for use on future SP-100-based missions. One possible major mission ground rule is the use of a single Space Shuttle launch. Thus, the mass in orbit at the reactor activation altitude would be limited by the Shuttle mass constraints. When the spacecraft subsystem masses are subtracted from this available mass limit, a maximum propellant mass may be calculated. Knowing the characteristics of each type of electric thruster allows maximum values of total impulse, mission velocity increment, and thrusting time to be calculated. Because ion thrusters easily operate at high values of efficiency (60 to 70%) and specific impulse (3000 to 5000 sec), they can impart large values of total impulse to a spacecraft. They also can be operated with separate control of the propellant flow rate and exhaust velocity. This paper presents values of demonstrated and projected performance of high power ion thrusters used in an analysis of electric propulsion for an SP-100 based mission.

  1. Large-area high-performance SERS substrates with deep controllable sub-10-nm gap structure fabricated by depositing Au film on the cicada wing

    NASA Astrophysics Data System (ADS)

    Jiwei, Qi; Yudong, Li; Ming, Yang; Qiang, Wu; Zongqiang, Chen; Wudeng, Wang; Wenqiang, Lu; Xuanyi, Yu; Jingjun, Xu; Qian, Sun

    2013-10-01

    Noble metal nanogap structure supports strong surface-enhanced Raman scattering (SERS) which can be used to detect single molecules. However, the lack of reproducible fabrication techniques with nanometer-level control over the gap size has limited practical applications. In this letter, by depositing the Au film onto the cicada wing, we engineer the ordered array of nanopillar structures on the wing to form large-area high-performance SERS substrates. Through the control of the thickness of the Au film deposited onto the cicada wing, the gap sizes between neighboring nanopillars are fine defined. SERS substrates with sub-10-nm gap sizes are obtained, which have the highest average Raman enhancement factor (EF) larger than 2 × 108, about 40 times as large as that of commercial Klarite® substrates. The cicada wings used as templates are natural and environment-friendly. The depositing method is low cost and high throughput so that our large-area high-performance SERS substrates have great advantage for chemical/biological sensing applications.

  2. High Performance Networks for High Impact Science

    SciTech Connect

    Scott, Mary A.; Bair, Raymond A.

    2003-02-13

    This workshop was the first major activity in developing a strategic plan for high-performance networking in the Office of Science. Held August 13 through 15, 2002, it brought together a selection of end users, especially representing the emerging, high-visibility initiatives, and network visionaries to identify opportunities and begin defining the path forward.

  3. Coparative assessment of irradiated proteins in potato tuber with untreated control by High Performance Liquid Chromatography (HPLC) and gel electrophoresis

    NASA Astrophysics Data System (ADS)

    Ghojaie, M.; Sayhoon, M.

    1995-02-01

    About 2% of the weight of potato tuber is composed of proteins. In spite of their low quantity the proteins play a key role in the physiological activities leading to the break of the dormancy period and start of the cell division. This causes sprouting and also greening due to chlorophyll formation. This in turn is always accompanied by the production of the glycoalkaloid solanine in the flesh of tuber. For evaluation of radiation effect (dose range 50-250 Gy) and probable structural changes (amino acid release), analysis of selected proteins (molecular range 5 × 10^4 - 2 × 10^5 Dalton) of potato tuber in both irradiated and control type by HPLC showed no considerable changes in retention times, but qualitative assessment of amino acids by Pico-Tag^TM Pre-derivatizing method had some changes in quantity of amino acids like lysine which was increased 1 month after irradiation while Glutamic acid had considerable decreasment after the same time of irradiation.

  4. Controlled soft-template synthesis of ultrathin C@FeS nanosheets with high-Li-storage performance.

    PubMed

    Xu, Chen; Zeng, Yi; Rui, Xianhong; Xiao, Ni; Zhu, Jixin; Zhang, Wenyu; Chen, Jing; Liu, Weiling; Tan, Huiteng; Hng, Huey Hoon; Yan, Qingyu

    2012-06-26

    We report a facile approach to prepare carbon-coated troilite FeS (C@FeS) nanosheets via surfactant-assisted solution-based synthesis. 1-Dodecanethiol is used as both the sulfur source and the surfactant, which may form different-shaped micelles to direct the growth of nanostructures. Under appropriate growth conditions, the iron and sulfur atoms react to form thin layers of FeS while the hydrocarbon tails of 1-dodecanethiol separate the thin FeS layers, which turn to carbon after annealing in Ar. Such an approach can be extended to grow C@FeS nanospheres and nanoplates by modifying the synthesis parameters. The C@FeS nanosheets display excellent Li storage properties with high specific capacities and stable charge/discharge cyclability, especially at fast charge/discharge rates.

  5. Improved Transient and Steady-State Performances of Series Resonant ZCS High-Frequency Inverter-Coupled Voltage Multiplier Converter with Dual Mode PFM Control Scheme

    NASA Astrophysics Data System (ADS)

    Chu, Enhui; Gamage, Laknath; Ishitobi, Manabu; Hiraki, Eiji; Nakaoka, Mutsuo

    The A variety of switched-mode high voltage DC power supplies using voltage-fed type or current-fed type high-frequency transformer resonant inverters using MOS gate bipolar power transistors; IGBTs have been recently developed so far for a medical-use X-ray high power generator. In general, the high voltage high power X-ray generator using voltage-fed high frequency inverter with a high voltage transformer link has to meet some performances such as (i) short rising period in start transient of X-ray tube voltage (ii) no overshoot transient response in tube voltage, (iii) minimized voltage ripple in periodic steady-state under extremely wide load variations and filament heater current fluctuation conditions of the X-ray tube. This paper presents two lossless inductor snubber-assisted series resonant zero current soft switching high-frequency inverter using a diode-capacitor ladder type voltage multiplier called Cockcroft-Walton circuit, which is effectively implemented for a high DC voltage X-ray power generator. This DC high voltage generator which incorporates pulse frequency modulated series resonant inverter using IGBT power module packages is based on the operation principle of zero current soft switching commutation scheme under discontinuous resonant current and continuous resonant current transition modes. This series capacitor compensated for transformer resonant power converter with a high frequency transformer linked voltage boost multiplier can efficiently work a novel selectively-changed dual mode PFM control scheme in order to improve the start transient and steady-state response characteristics and can completely achieve stable zero current soft switching commutation tube filament current dependent for wide load parameter setting values with the aid of two lossless inductor snubbers. It is proved on the basis of simulation and experimental results in which a simple and low cost control implementation based on selectively-changed dual-mode PFM for

  6. High-Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Reuhs, Bradley L.; Rounds, Mary Ann

    High-performance liquid chromatography (HPLC) developed during the 1960s as a direct offshoot of classic column liquid chromatography through improvements in the technology of columns and instrumental components (pumps, injection valves, and detectors). Originally, HPLC was the acronym for high-pressure liquid chromatography, reflecting the high operating pressures generated by early columns. By the late 1970s, however, high-performance liquid chromatography had become the preferred term, emphasizing the effective separations achieved. In fact, newer columns and packing materials offer high performance at moderate pressure (although still high pressure relative to gravity-flow liquid chromatography). HPLC can be applied to the analysis of any compound with solubility in a liquid that can be used as the mobile phase. Although most frequently employed as an analytical technique, HPLC also may be used in the preparative mode.

  7. High-Performance Ball Bearing

    NASA Technical Reports Server (NTRS)

    Bursey, Roger W., Jr.; Haluck, David A.; Olinger, John B.; Owen, Samuel S.; Poole, William E.

    1995-01-01

    High-performance bearing features strong, lightweight, self-lubricating cage with self-lubricating liners in ball apertures. Designed to operate at high speed (tens of thousands of revolutions per minute) in cryogenic environment like liquid-oxygen or liquid-hydrogen turbopump. Includes inner race, outer race, and cage keeping bearing balls equally spaced.

  8. High performance dielectric materials development

    NASA Technical Reports Server (NTRS)

    Piche, Joe; Kirchner, Ted; Jayaraj, K.

    1994-01-01

    The mission of polymer composites materials technology is to develop materials and processing technology to meet DoD and commercial needs. The following are outlined in this presentation: high performance capacitors, high temperature aerospace insulation, rationale for choosing Foster-Miller (the reporting industry), the approach to the development and evaluation of high temperature insulation materials, and the requirements/evaluation parameters. Supporting tables and diagrams are included.

  9. Nonlinear feedback control of highly manoeuvrable aircraft

    NASA Technical Reports Server (NTRS)

    Garrard, William L.; Enns, Dale F.; Snell, S. A.

    1992-01-01

    This paper describes the application of nonlinear quadratic regulator (NLQR) theory to the design of control laws for a typical high-performance aircraft. The NLQR controller design is performed using truncated solutions of the Hamilton-Jacobi-Bellman equation of optimal control theory. The performance of the NLQR controller is compared with the performance of a conventional P + I gain scheduled controller designed by applying standard frequency response techniques to the equations of motion of the aircraft linearized at various angles of attack. Both techniques result in control laws which are very similar in structure to one another and which yield similar performance. The results of applying both control laws to a high-g vertical turn are illustrated by nonlinear simulation.

  10. INL High Performance Building Strategy

    SciTech Connect

    Jennifer D. Morton

    2010-02-01

    High performance buildings, also known as sustainable buildings and green buildings, are resource efficient structures that minimize the impact on the environment by using less energy and water, reduce solid waste and pollutants, and limit the depletion of natural resources while also providing a thermally and visually comfortable working environment that increases productivity for building occupants. As Idaho National Laboratory (INL) becomes the nation’s premier nuclear energy research laboratory, the physical infrastructure will be established to help accomplish this mission. This infrastructure, particularly the buildings, should incorporate high performance sustainable design features in order to be environmentally responsible and reflect an image of progressiveness and innovation to the public and prospective employees. Additionally, INL is a large consumer of energy that contributes to both carbon emissions and resource inefficiency. In the current climate of rising energy prices and political pressure for carbon reduction, this guide will help new construction project teams to design facilities that are sustainable and reduce energy costs, thereby reducing carbon emissions. With these concerns in mind, the recommendations described in the INL High Performance Building Strategy (previously called the INL Green Building Strategy) are intended to form the INL foundation for high performance building standards. This revised strategy incorporates the latest federal and DOE orders (Executive Order [EO] 13514, “Federal Leadership in Environmental, Energy, and Economic Performance” [2009], EO 13423, “Strengthening Federal Environmental, Energy, and Transportation Management” [2007], and DOE Order 430.2B, “Departmental Energy, Renewable Energy, and Transportation Management” [2008]), the latest guidelines, trends, and observations in high performance building construction, and the latest changes to the Leadership in Energy and Environmental Design

  11. High Performance Bulk Thermoelectric Materials

    SciTech Connect

    Ren, Zhifeng

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  12. High performance storable propellant resistojet

    NASA Astrophysics Data System (ADS)

    Vaughan, C. E.

    1992-01-01

    From 1965 until 1985 resistojets were used for a limited number of space missions. Capability increased in stages from an initial application using a 90 W gN2 thruster operating at 123 sec specific impulse (Isp) to a 830 W N2H4 thruster operating at 305 sec Isp. Prior to 1985 fewer than 100 resistojets were known to have been deployed on spacecraft. Building on this base NASA embarked upon the High Performance Storable Propellant Resistojet (HPSPR) program to significantly advance the resistojet state-of-the-art. Higher performance thrusters promised to increase the market demand for resistojets and enable space missions requiring higher performance. During the program three resistojets were fabricated and tested. High temperature wire and coupon materials tests were completed. A life test was conducted on an advanced gas generator.

  13. Aligning Task Control with Desire for Control: Implications for Performance

    PubMed Central

    Ramsey, Alex T.; Etcheverry, Paul E.

    2015-01-01

    The current study examined whether matches between task control and participants' desire for control over their environment lead to better task performance than mismatches. Work control and desire for control were manipulated, and participants engaged in timed tasks. As predicted, performance was higher in cases of match, even when task control and desire for control were low. Task control and desire for control may predict work performance in combination, highlighting the importance of Person-Environment Fit theory for both selection and work design. By manipulating desire for control, our research also explores the potentially state-dependent quality of this individual difference variable. PMID:26045630

  14. High Performance Tools And Technologies

    SciTech Connect

    Collette, M R; Corey, I R; Johnson, J R

    2005-01-24

    This goal of this project was to evaluate the capability and limits of current scientific simulation development tools and technologies with specific focus on their suitability for use with the next generation of scientific parallel applications and High Performance Computing (HPC) platforms. The opinions expressed in this document are those of the authors, and reflect the authors' current understanding and functionality of the many tools investigated. As a deliverable for this effort, we are presenting this report describing our findings along with an associated spreadsheet outlining current capabilities and characteristics of leading and emerging tools in the high performance computing arena. This first chapter summarizes our findings (which are detailed in the other chapters) and presents our conclusions, remarks, and anticipations for the future. In the second chapter, we detail how various teams in our local high performance community utilize HPC tools and technologies, and mention some common concerns they have about them. In the third chapter, we review the platforms currently or potentially available to utilize these tools and technologies on to help in software development. Subsequent chapters attempt to provide an exhaustive overview of the available parallel software development tools and technologies, including their strong and weak points and future concerns. We categorize them as debuggers, memory checkers, performance analysis tools, communication libraries, data visualization programs, and other parallel development aides. The last chapter contains our closing information. Included with this paper at the end is a table of the discussed development tools and their operational environment.

  15. ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS

    SciTech Connect

    WONG, CPC; MALANG, S; NISHIO, S; RAFFRAY, R; SAGARA, S

    2002-04-01

    OAK A271 ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS. First wall and blanket (FW/blanket) design is a crucial element in the performance and acceptance of a fusion power plant. High temperature structural and breeding materials are needed for high thermal performance. A suitable combination of structural design with the selected materials is necessary for D-T fuel sufficiency. Whenever possible, low afterheat, low chemical reactivity and low activation materials are desired to achieve passive safety and minimize the amount of high-level waste. Of course the selected fusion FW/blanket design will have to match the operational scenarios of high performance plasma. The key characteristics of eight advanced high performance FW/blanket concepts are presented in this paper. Design configurations, performance characteristics, unique advantages and issues are summarized. All reviewed designs can satisfy most of the necessary design goals. For further development, in concert with the advancement in plasma control and scrape off layer physics, additional emphasis will be needed in the areas of first wall coating material selection, design of plasma stabilization coils, consideration of reactor startup and transient events. To validate the projected performance of the advanced FW/blanket concepts the critical element is the need for 14 MeV neutron irradiation facilities for the generation of necessary engineering design data and the prediction of FW/blanket components lifetime and availability.

  16. Simultaneous Determinations of Eleven Bioactive Components in Suanzaoren Decoction Granules by High-Performance Liquid Chromatography and Its Application to the Quality Control in Productive Processes.

    PubMed

    Kuang, Yali; He, Bosai; DU, Yiyang; Li, Jiahui; Wang, Di; Bi, Kaishun; Li, Qing

    2016-01-01

    A simple and reliable method using high-performance liquid chromatography coupled with a photodiode array detector (HPLC-PDA) was firstly established for the determinations of eleven bioactive compounds (neomangiferin, mangiferin, spinosin, liquiritin apioside, liquiritin, fumalic acid, 6'''-feruloylspinosin, senkyunolide I, isoliquiritin, glycyrrhizic acid and senkyunolide A) in Suanzaoren decoction (SZRD) extract and its granules. The chromatographic analysis was performed on a C18 column at 30°C. Excellent linear behaviors over the investigated concentration ranges were observed with the values of R(2) being higher than 0.9990 for all analytes. The developed method showed good precision and accuracy with overall intra- and inter-day variations of less than 2.0%, and overall recoveries in the range of 97.2 - 102.1%. The validated method was successfully applied to the determination of eleven components in SZRD samples from different production batches, including SZRD extract, lab-made SZRD granules and clinical medicine. This accurate and reliable HPLC-PDA method will be helpful for improving the quality evaluation of SZRD granules and its quality control in productive processes. PMID:27682396

  17. High Efficiency, High Performance Clothes Dryer

    SciTech Connect

    Peter Pescatore; Phil Carbone

    2005-03-31

    This program covered the development of two separate products; an electric heat pump clothes dryer and a modulating gas dryer. These development efforts were independent of one another and are presented in this report in two separate volumes. Volume 1 details the Heat Pump Dryer Development while Volume 2 details the Modulating Gas Dryer Development. In both product development efforts, the intent was to develop high efficiency, high performance designs that would be attractive to US consumers. Working with Whirlpool Corporation as our commercial partner, TIAX applied this approach of satisfying consumer needs throughout the Product Development Process for both dryer designs. Heat pump clothes dryers have been in existence for years, especially in Europe, but have not been able to penetrate the market. This has been especially true in the US market where no volume production heat pump dryers are available. The issue has typically been around two key areas: cost and performance. Cost is a given in that a heat pump clothes dryer has numerous additional components associated with it. While heat pump dryers have been able to achieve significant energy savings compared to standard electric resistance dryers (over 50% in some cases), designs to date have been hampered by excessively long dry times, a major market driver in the US. The development work done on the heat pump dryer over the course of this program led to a demonstration dryer that delivered the following performance characteristics: (1) 40-50% energy savings on large loads with 35 F lower fabric temperatures and similar dry times; (2) 10-30 F reduction in fabric temperature for delicate loads with up to 50% energy savings and 30-40% time savings; (3) Improved fabric temperature uniformity; and (4) Robust performance across a range of vent restrictions. For the gas dryer development, the concept developed was one of modulating the gas flow to the dryer throughout the dry cycle. Through heat modulation in a

  18. High performance ammonium nitrate propellant

    NASA Technical Reports Server (NTRS)

    Anderson, F. A. (Inventor)

    1979-01-01

    A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

  19. New, high performance rotating parachute

    SciTech Connect

    Pepper, W.B. Jr.

    1983-01-01

    A new rotating parachute has been designed primarily for recovery of high performance reentry vehicles. Design and development/testing results are presented from low-speed wind tunnel testing, free-flight deployments at transonic speeds and tests in a supersonic wind tunnel at Mach 2.0. Drag coefficients of 1.15 based on the 2-ft diameter of the rotor have been measured in the wind tunnel. Stability of the rotor is excellent.

  20. Comparison of Raman spectroscopy vs. high performance liquid chromatography for quality control of complex therapeutic objects: model of elastomeric portable pumps filled with a fluorouracil solution.

    PubMed

    Bourget, Philippe; Amin, Alexandre; Vidal, Fabrice; Merlette, Christophe; Lagarce, Frédéric

    2014-03-01

    This study compares the performance of a reference method of HPLC to Raman spectroscopy (RS) for the analytical quality control (AQC) of complex therapeutic objects. We assessed a model consisting of a widely used anticancer drug, i.e., 5-fluorouracil, which was compounded in a complex medical device, i.e., an elastomeric portable infusion pump. In view of the main objective, the two methods provided excellent results for the analytical validation key criteria, i.e., trueness, precision and accuracy, ranging from 7.5 to 50mg/mL and in either isotonic sodium or 5% dextrose. The Spearman and Kendall correlation tests (p-value<1×10(-15)) and the statistical studies performed on the graphs confirm a strong correlation in the results between RS and the standard HPLC under the experimental conditions. The selection of a spectral interval between 700 and 1400cm(-1) for both the characterization and quantification by RS was the result of a gradual process optimization, combining matrix and packaging responses. In this new application, we demonstrate at least eight benefits of RS: (a) operator safety, (b) elimination of disposables, (c) elimination of analysis waste, which contributes to the protection of the environment, (d) a fast analytical response of less than 2min, (e) the ability to identify the solubilizing phase, (f) reduction of the risk of errors because no intrusion or dilution are needed, (g) negligible maintenance costs and (h) a reduction in the budget dedicated to technician training. Overall, we indicate the potential of non-intrusive AQC performed by RS, especially when the analysis is not possible using the usual techniques, and the technique's high potential as a contributor to the safety of medication.

  1. Comparison of Raman spectroscopy vs. high performance liquid chromatography for quality control of complex therapeutic objects: model of elastomeric portable pumps filled with a fluorouracil solution.

    PubMed

    Bourget, Philippe; Amin, Alexandre; Vidal, Fabrice; Merlette, Christophe; Lagarce, Frédéric

    2014-03-01

    This study compares the performance of a reference method of HPLC to Raman spectroscopy (RS) for the analytical quality control (AQC) of complex therapeutic objects. We assessed a model consisting of a widely used anticancer drug, i.e., 5-fluorouracil, which was compounded in a complex medical device, i.e., an elastomeric portable infusion pump. In view of the main objective, the two methods provided excellent results for the analytical validation key criteria, i.e., trueness, precision and accuracy, ranging from 7.5 to 50mg/mL and in either isotonic sodium or 5% dextrose. The Spearman and Kendall correlation tests (p-value<1×10(-15)) and the statistical studies performed on the graphs confirm a strong correlation in the results between RS and the standard HPLC under the experimental conditions. The selection of a spectral interval between 700 and 1400cm(-1) for both the characterization and quantification by RS was the result of a gradual process optimization, combining matrix and packaging responses. In this new application, we demonstrate at least eight benefits of RS: (a) operator safety, (b) elimination of disposables, (c) elimination of analysis waste, which contributes to the protection of the environment, (d) a fast analytical response of less than 2min, (e) the ability to identify the solubilizing phase, (f) reduction of the risk of errors because no intrusion or dilution are needed, (g) negligible maintenance costs and (h) a reduction in the budget dedicated to technician training. Overall, we indicate the potential of non-intrusive AQC performed by RS, especially when the analysis is not possible using the usual techniques, and the technique's high potential as a contributor to the safety of medication. PMID:24463044

  2. High Performance Proactive Digital Forensics

    NASA Astrophysics Data System (ADS)

    Alharbi, Soltan; Moa, Belaid; Weber-Jahnke, Jens; Traore, Issa

    2012-10-01

    With the increase in the number of digital crimes and in their sophistication, High Performance Computing (HPC) is becoming a must in Digital Forensics (DF). According to the FBI annual report, the size of data processed during the 2010 fiscal year reached 3,086 TB (compared to 2,334 TB in 2009) and the number of agencies that requested Regional Computer Forensics Laboratory assistance increasing from 689 in 2009 to 722 in 2010. Since most investigation tools are both I/O and CPU bound, the next-generation DF tools are required to be distributed and offer HPC capabilities. The need for HPC is even more evident in investigating crimes on clouds or when proactive DF analysis and on-site investigation, requiring semi-real time processing, are performed. Although overcoming the performance challenge is a major goal in DF, as far as we know, there is almost no research on HPC-DF except for few papers. As such, in this work, we extend our work on the need of a proactive system and present a high performance automated proactive digital forensic system. The most expensive phase of the system, namely proactive analysis and detection, uses a parallel extension of the iterative z algorithm. It also implements new parallel information-based outlier detection algorithms to proactively and forensically handle suspicious activities. To analyse a large number of targets and events and continuously do so (to capture the dynamics of the system), we rely on a multi-resolution approach to explore the digital forensic space. Data set from the Honeynet Forensic Challenge in 2001 is used to evaluate the system from DF and HPC perspectives.

  3. Size exclusion and reversed-phase high-performance liquid chromatography/UV for routine control of thermal processing of cows' and donkey milk major proteins.

    PubMed

    Pinho, Carina; Martins, Zita E; Petisca, Catarina; Figurska, Agata M; Pinho, Olívia; Ferreira, Isabel M P L V O

    2012-05-01

    Cows' and donkey milks (raw and thermally processed) and respective whey were analysed for quantification of major proteins. Two different chromatographic approaches, size exclusion (SE-HPLC) and reversed-phase high performance liquid chromatography (RP-HPLC) both coupled to UV detection were used. Usefulness of these methods for routine control of the effect of thermal processing was evaluated. The external standard method was used to calibrate the SE-HPLC and RP-HPLC systems. Concerning quantification of β-lactoglobulin (β-lg), α-lactalbumin (α-la), lysozyme (lys), and total casein (cn), no significant differences between results obtained by SE-HPLC and by RP-HPLC (t-test, P>0·05) were observed for raw milks and whey. Heating of cows' milk promoted aggregation of denatured proteins as observed by SE-HPLC, whereas α-la and β-lg from donkey milk were stable to thermal processing at 100 °C (5 min). Lys was quantified in donkey raw milk and whey however, in thermally processed donkey milk lys was denatured and could not be quantified by HPLC.

  4. Pilot Implementation of a Field Study Design to Evaluate the Impact of Source Control Measures on Indoor Air Quality in High Performance Homes

    SciTech Connect

    Widder, Sarah H.; Chamness, Michele A.; Petersen, Joseph M.; Singer, Brett C.; Maddalena, Randy L.; Destaillats, Hugo; Russell, M. L.

    2014-10-01

    -emitting and “conventional” materials as installed in newly constructed residential homes using both (1) highly controlled, short-term active samples to precisely characterize the building-related chemical emissions and building contents and (2) a week-long passive sample designed to capture the impact of occupant behavior and related activities on measured IAQ contaminant levels indoors. The combination of detailed short-term measurements with the home under controlled/consistent conditions during pre- and post-occupancy and the week-long passive sampling data provide the opportunity to begin to separate the different emission sources and help isolate and quantify variability in the monitored homes. Between April and August 2014, the research team performed pre-occupancy and post-occupancy sampling in one conventional home and two homes built with low-emitting materials that were generally consistent with EPA’s Indoor airPLUS guidelines. However, for a number of reasons, the full experimental plan was not implemented. The project was intended to continue for up to three years to asses long-term changes in IAQ but the project was limited to one calendar year. As a result, several of the primary research questions related to seasonal impacts and the long-term trends in IAQ could not be addressed. In addition, there were several unexpected issues related to recruiting, availability of home types, and difficulty coordinating with builders/realtors/homeowners. Several field monitoring issues also came up that provide “lessons learned” that led to improvements to the original monitoring plan. The project produced a good experimental plan that is expected to be be useful for future efforts collecting data to support answering these same or similar research questions.

  5. High Performance Field Reversed Configurations

    NASA Astrophysics Data System (ADS)

    Binderbauer, Michl

    2014-10-01

    The field-reversed configuration (FRC) is a prolate compact toroid with poloidal magnetic fields. FRCs could lead to economic fusion reactors with high power density, simple geometry, natural divertor, ease of translation, and possibly capable of burning aneutronic fuels. However, as in other high-beta plasmas, there are stability and confinement concerns. These concerns can be addressed by introducing and maintaining a significant fast ion population in the system. This is the approach adopted by TAE and implemented for the first time in the C-2 device. Studying the physics of FRCs driven by Neutral Beam (NB) injection, significant improvements were made in confinement and stability. Early C-2 discharges had relatively good confinement, but global power losses exceeded the available NB input power. The addition of axially streaming plasma guns, magnetic end plugs as well as advanced surface conditioning leads to dramatic reductions in turbulence driven losses and greatly improved stability. As a result, fast ion confinement significantly improved and allowed for build-up of a dominant fast particle population. Under such appropriate conditions we achieved highly reproducible, long-lived, macroscopically stable FRCs with record lifetimes. This demonstrated many beneficial effects of large orbit particles and their performance impact on FRCs Together these achievements point to the prospect of beam-driven FRCs as a path toward fusion reactors. This presentation will review and expand on key results and present context for their interpretation.

  6. The High Performance Storage System

    SciTech Connect

    Coyne, R.A.; Hulen, H.; Watson, R.

    1993-09-01

    The National Storage Laboratory (NSL) was organized to develop, demonstrate and commercialize technology for the storage system that will be the future repositories for our national information assets. Within the NSL four Department of Energy laboratories and IBM Federal System Company have pooled their resources to develop an entirely new High Performance Storage System (HPSS). The HPSS project concentrates on scalable parallel storage system for highly parallel computers as well as traditional supercomputers and workstation clusters. Concentrating on meeting the high end of storage system and data management requirements, HPSS is designed using network-connected storage devices to transfer data at rates of 100 million bytes per second and beyond. The resulting products will be portable to many vendor`s platforms. The three year project is targeted to be complete in 1995. This paper provides an overview of the requirements, design issues, and architecture of HPSS, as well as a description of the distributed, multi-organization industry and national laboratory HPSS project.

  7. LPV Controller Interpolation for Improved Gain-Scheduling Control Performance

    NASA Technical Reports Server (NTRS)

    Wu, Fen; Kim, SungWan

    2002-01-01

    In this paper, a new gain-scheduling control design approach is proposed by combining LPV (linear parameter-varying) control theory with interpolation techniques. The improvement of gain-scheduled controllers can be achieved from local synthesis of Lyapunov functions and continuous construction of a global Lyapunov function by interpolation. It has been shown that this combined LPV control design scheme is capable of improving closed-loop performance derived from local performance improvement. The gain of the LPV controller will also change continuously across parameter space. The advantages of the newly proposed LPV control is demonstrated through a detailed AMB controller design example.

  8. Feedback control laws for highly maneuverable aircraft

    NASA Technical Reports Server (NTRS)

    Garrard, William L.; Balas, Gary J.

    1992-01-01

    The results of a study of the application of H infinity and mu synthesis techniques to the design of feedback control laws for the longitudinal dynamics of the High Angle of Attack Research Vehicle (HARV) are presented. The objective of this study is to develop methods for the design of feedback control laws which cause the closed loop longitudinal dynamics of the HARV to meet handling quality specifications over the entire flight envelope. Control law designs are based on models of the HARV linearized at various flight conditions. The control laws are evaluated by both linear and nonlinear simulations of typical maneuvers. The fixed gain control laws resulting from both the H infinity and mu synthesis techniques result in excellent performance even when the aircraft performs maneuvers in which the system states vary significantly from their equilibrium design values. Both the H infinity and mu synthesis control laws result in performance which compares favorably with an existing baseline longitudinal control law.

  9. TRMM On Orbit Attitude Control System Performance

    NASA Technical Reports Server (NTRS)

    Robertson, Brent; Placanica, Sam; Morgenstern, Wendy

    1999-01-01

    This paper presents an overview of the Tropical Rainfall Measuring Mission (TRMM) Attitude Control System (ACS) along with detailed in-flight performance results for each operational mode. The TRMM spacecraft is an Earth-pointed, zero momentum bias satellite launched on November 27, 1997 from Tanegashima Space Center, Japan. TRMM is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan designed to monitor and study tropical rainfall and the associated release of energy. Launched to provide a validation for poorly known rainfall data sets generated by global climate models, TRMM has demonstrated its utility by reducing uncertainties in global rainfall measurements by a factor of two. The ACS is comprised of Attitude Control Electronics (ACE), an Earth Sensor Assembly (ESA), Digital Sun Sensors (DSS), Inertial Reference Units (IRU), Three Axis Magnetometers (TAM), Coarse Sun Sensors (CSS), Magnetic Torquer Bars (MTB), Reaction Wheel Assemblies (RWA), Engine Valve Drivers (EVD) and thrusters. While in Mission Mode, the ESA provides roll and pitch axis attitude error measurements and the DSS provide yaw updates twice per orbit. In addition, the TAM in combination with the IRU and DSS can be used to provide pointing in a contingency attitude determination mode which does not rely on the ESA. Although the ACS performance to date has been highly successful, lessons were learned during checkout and initial on-orbit operation. This paper describes the design, on-orbit checkout, performance and lessons learned for the TRMM ACS.

  10. Characterization of a high-pressure diesel fuel injection system as a control technology option to improve engine performance and reduce exhaust emissions

    NASA Technical Reports Server (NTRS)

    Mcfadden, J. J.; Dezelick, R. A.; Barrows, R. R.

    1983-01-01

    Test results from a high pressure electronically controlled fuel injection system are compared with a commercial mechanical injection system on a single cylinder, diesel test engine using an inlet boost pressure of 2.6:1. The electronic fuel injection system achieved high pressure by means of a fluid intensifier with peak injection pressures of 47 to 69 MPa. Reduced exhaust emissions were demonstrated with an increasing rate of injection followed by a fast cutoff of injection. The reduction in emissions is more responsive to the rate of injection and injection timing than to high peak injection pressure.

  11. High performance anode for advanced Li batteries

    SciTech Connect

    Lake, Carla

    2015-11-02

    The overall objective of this Phase I SBIR effort was to advance the manufacturing technology for ASI’s Si-CNF high-performance anode by creating a framework for large volume production and utilization of low-cost Si-coated carbon nanofibers (Si-CNF) for the battery industry. This project explores the use of nano-structured silicon which is deposited on a nano-scale carbon filament to achieve the benefits of high cycle life and high charge capacity without the consequent fading of, or failure in the capacity resulting from stress-induced fracturing of the Si particles and de-coupling from the electrode. ASI’s patented coating process distinguishes itself from others, in that it is highly reproducible, readily scalable and results in a Si-CNF composite structure containing 25-30% silicon, with a compositionally graded interface at the Si-CNF interface that significantly improve cycling stability and enhances adhesion of silicon to the carbon fiber support. In Phase I, the team demonstrated the production of the Si-CNF anode material can successfully be transitioned from a static bench-scale reactor into a fluidized bed reactor. In addition, ASI made significant progress in the development of low cost, quick testing methods which can be performed on silicon coated CNFs as a means of quality control. To date, weight change, density, and cycling performance were the key metrics used to validate the high performance anode material. Under this effort, ASI made strides to establish a quality control protocol for the large volume production of Si-CNFs and has identified several key technical thrusts for future work. Using the results of this Phase I effort as a foundation, ASI has defined a path forward to commercialize and deliver high volume and low-cost production of SI-CNF material for anodes in Li-ion batteries.

  12. High performance Cu adhesion coating

    SciTech Connect

    Lee, K.W.; Viehbeck, A.; Chen, W.R.; Ree, M.

    1996-12-31

    Poly(arylene ether benzimidazole) (PAEBI) is a high performance thermoplastic polymer with imidazole functional groups forming the polymer backbone structure. It is proposed that upon coating PAEBI onto a copper surface the imidazole groups of PAEBI form a bond with or chelate to the copper surface resulting in strong adhesion between the copper and polymer. Adhesion of PAEBI to other polymers such as poly(biphenyl dianhydride-p-phenylene diamine) (BPDA-PDA) polyimide is also quite good and stable. The resulting locus of failure as studied by XPS and IR indicates that PAEBI gives strong cohesive adhesion to copper. Due to its good adhesion and mechanical properties, PAEBI can be used in fabricating thin film semiconductor packages such as multichip module dielectric (MCM-D) structures. In these applications, a thin PAEBI coating is applied directly to a wiring layer for enhancing adhesion to both the copper wiring and the polymer dielectric surface. In addition, a thin layer of PAEBI can also function as a protection layer for the copper wiring, eliminating the need for Cr or Ni barrier metallurgies and thus significantly reducing the number of process steps.

  13. ALMA high performance nutating subreflector

    NASA Astrophysics Data System (ADS)

    Gasho, Victor L.; Radford, Simon J. E.; Kingsley, Jeffrey S.

    2003-02-01

    For the international ALMA project"s prototype antennas, we have developed a high performance, reactionless nutating subreflector (chopping secondary mirror). This single axis mechanism can switch the antenna"s optical axis by +/-1.5" within 10 ms or +/-5" within 20 ms and maintains pointing stability within the antenna"s 0.6" error budget. The light weight 75 cm diameter subreflector is made of carbon fiber composite to achieve a low moment of inertia, <0.25 kg m2. Its reflecting surface was formed in a compression mold. Carbon fiber is also used together with Invar in the supporting structure for thermal stability. Both the subreflector and the moving coil motors are mounted on flex pivots and the motor magnets counter rotate to absorb the nutation reaction force. Auxiliary motors provide active damping of external disturbances, such as wind gusts. Non contacting optical sensors measure the positions of the subreflector and the motor rocker. The principle mechanical resonance around 20 Hz is compensated with a digital PID servo loop that provides a closed loop bandwidth near 100 Hz. Shaped transitions are used to avoid overstressing mechanical links.

  14. Controllable synthesis of SnO2@C yolk-shell nanospheres as a high-performance anode material for lithium ion batteries.

    PubMed

    Wang, Jinxiu; Li, Wei; Wang, Fei; Xia, Yongyao; Asiri, Abdullah M; Zhao, Dongyuan

    2014-03-21

    In this work, we report a facile synthesis of uniform SnO2@C yolk-shell nanospheres as high-performance anode materials for lithium ion batteries (LIBs). The yolk-shell structured SnO2@C nanospheres were fabricated through a two-step sol-gel coating process by using tetraethyl orthosilicate (TEOS) and resorcinol-formaldehyde (RF) as precursors, where the silica interlayer not only acts as a template to produce the void space, but also promotes the coating of the RF layer. The synthesis is easy to operate and allows tailoring the carbon shell thickness and void space size. The resultant SnO2@C yolk-shell nanospheres possess a hollow highly crystalline SnO2 core (280-380 nm), tailored carbon shell thickness (15-25 nm) and a large void space size (100-160 nm), a high surface area (∼205 m(2) g(-1)), a large pore volume (∼0.25 cm(3) g(-1)), as well as a high SnO2 content (77 wt%). When evaluated as an anode of LIBs, the materials manifest superior electrochemical performance with a high lithium storage capability (2190 mA h g(-1) in initial discharge capacity; >950 mA h g(-1) in the first 10 cycles), a good cycling performance and an excellent rate capability.

  15. Nanotubular structured Si-based multicomponent anodes for high-performance lithium-ion batteries with controllable pore size via coaxial electro-spinning.

    PubMed

    Ryu, Jaegeon; Choi, Sinho; Bok, Taesoo; Park, Soojin

    2015-04-14

    We demonstrate a simple but straightforward process for the synthesis of nanotube-type Si-based multicomponents by combining a coaxial electrospinning technique and subsequent metallothermic reduction reaction. Si-based multicomponent anodes consisting of Si, alumina and titanium silicide show several advantages for high-performance lithium-ion batteries. Alumina and titanium silicide, which have high mechanical properties, act as an effective buffer layer for the large volume change of Si, resulting in outstanding volume suppression behavior (volume expansion of only 14%). Moreover, electrically conductive titanium silicide layers located at the inner and outer layers of a Si nanotube exhibit a high initial coulombic efficiency of 88.5% and an extraordinary rate capability. Nanotubular structured Si-based multicomponents with mechanically and electrically improved components can be used as a promising alternative to conventional graphite anode materials. This synthetic route can be extended to other high capacity lithium-ion battery anode materials. PMID:25772327

  16. Nanotubular structured Si-based multicomponent anodes for high-performance lithium-ion batteries with controllable pore size via coaxial electro-spinning.

    PubMed

    Ryu, Jaegeon; Choi, Sinho; Bok, Taesoo; Park, Soojin

    2015-04-14

    We demonstrate a simple but straightforward process for the synthesis of nanotube-type Si-based multicomponents by combining a coaxial electrospinning technique and subsequent metallothermic reduction reaction. Si-based multicomponent anodes consisting of Si, alumina and titanium silicide show several advantages for high-performance lithium-ion batteries. Alumina and titanium silicide, which have high mechanical properties, act as an effective buffer layer for the large volume change of Si, resulting in outstanding volume suppression behavior (volume expansion of only 14%). Moreover, electrically conductive titanium silicide layers located at the inner and outer layers of a Si nanotube exhibit a high initial coulombic efficiency of 88.5% and an extraordinary rate capability. Nanotubular structured Si-based multicomponents with mechanically and electrically improved components can be used as a promising alternative to conventional graphite anode materials. This synthetic route can be extended to other high capacity lithium-ion battery anode materials.

  17. Nanotubular structured Si-based multicomponent anodes for high-performance lithium-ion batteries with controllable pore size via coaxial electro-spinning

    NASA Astrophysics Data System (ADS)

    Ryu, Jaegeon; Choi, Sinho; Bok, Taesoo; Park, Soojin

    2015-03-01

    We demonstrate a simple but straightforward process for the synthesis of nanotube-type Si-based multicomponents by combining a coaxial electrospinning technique and subsequent metallothermic reduction reaction. Si-based multicomponent anodes consisting of Si, alumina and titanium silicide show several advantages for high-performance lithium-ion batteries. Alumina and titanium silicide, which have high mechanical properties, act as an effective buffer layer for the large volume change of Si, resulting in outstanding volume suppression behavior (volume expansion of only 14%). Moreover, electrically conductive titanium silicide layers located at the inner and outer layers of a Si nanotube exhibit a high initial coulombic efficiency of 88.5% and an extraordinary rate capability. Nanotubular structured Si-based multicomponents with mechanically and electrically improved components can be used as a promising alternative to conventional graphite anode materials. This synthetic route can be extended to other high capacity lithium-ion battery anode materials.We demonstrate a simple but straightforward process for the synthesis of nanotube-type Si-based multicomponents by combining a coaxial electrospinning technique and subsequent metallothermic reduction reaction. Si-based multicomponent anodes consisting of Si, alumina and titanium silicide show several advantages for high-performance lithium-ion batteries. Alumina and titanium silicide, which have high mechanical properties, act as an effective buffer layer for the large volume change of Si, resulting in outstanding volume suppression behavior (volume expansion of only 14%). Moreover, electrically conductive titanium silicide layers located at the inner and outer layers of a Si nanotube exhibit a high initial coulombic efficiency of 88.5% and an extraordinary rate capability. Nanotubular structured Si-based multicomponents with mechanically and electrically improved components can be used as a promising alternative to

  18. Performance specification for control tower display systems

    NASA Astrophysics Data System (ADS)

    Aleva, Denise L.; Meyer, Frederick M.

    2003-09-01

    Personnel in airport control towers monitor and direct the takeoff of outgoing aircraft, landing of incoming aircraft and all movements of aircraft on the ground. Although the primary source of information for the Local Controller, Assistant Local Controller and the Ground Controller is the real world viewed through the windows of the control tower, electronic displays are also used to provide situation awareness. Due to the criticality of the work to be performed by the controllers and the rather unique environment of the air traffic control tower, display hardware standards, which have been developed for general use, are not directly applicable. The Federal Aviation Administration (FAA) requested assistance of Air Force Research Laboratory Human Effectiveness Directorate in producing a document which can be adopted as a Tower Display Standard usable by display engineers, human factors practitioners and system integrators. Particular emphasis was placed on human factors issues applicable to the control tower environment and controller task demands.

  19. Temperature controlled high voltage regulator

    DOEpatents

    Chiaro, Jr., Peter J.; Schulze, Gerald K.

    2004-04-20

    A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

  20. Controlling your high blood pressure

    MedlinePlus

    Controlling hypertension ... when you wake up. For people with very high blood pressure, this is when they are most at risk ... 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed ...

  1. Process controls for improving bioleaching performance of both Li and Co from spent lithium ion batteries at high pulp density and its thermodynamics and kinetics exploration.

    PubMed

    Niu, Zhirui; Zou, Yikan; Xin, Baoping; Chen, Shi; Liu, Changhao; Li, Yuping

    2014-08-01

    Release of Co and Li from spent lithium ion batteries (LIBs) by bioleaching has attracted growing attentions. However, the pulp density was only 1% or lower, meaning that a huge quantity of media was required for bioleaching. In this work, bioleaching behavior of the spent LIBs at pulp densities ranging from 1% to 4% was investigated and process controls to improve bioleaching performance at pulp density of 2% were explored. The results showed that the pulp density exerted a considerable influence on leaching performance of Co and Li. The bioleaching efficiency decreased respectively from 52% to 10% for Co and from 80% to 37% for Li when pulp density rose from 1% to 4%. However, the maximum extraction efficiency of 89% for Li and 72% for Co was obtained at pulp density of 2% by process controls. Bioleaching of the spent LIBs has much greater potential to occur than traditional chemical leaching based on thermodynamics analysis. The product layer diffusion model described best bioleaching behavior of Co and Li.

  2. High Performance Torso Cooling Garment

    NASA Technical Reports Server (NTRS)

    Conger, Bruce; Makinen, Janice

    2016-01-01

    The concept proposed in this paper is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area, which could facilitate removal of LCVG tubing from the arms and legs, thereby increasing suited crew member mobility. EVA space suit mobility in micro-gravity is challenging, and it becomes even more challenging in the gravity of Mars. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased. This increase in efficiency could provide the required liquid cooling via torso tubing only; no arm or leg LCVG tubing would be required. Benefits of this approach include increased crewmember mobility, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development. This report describes analysis and test activities performed to evaluate the potential improvements to the thermal performance of the LCVG. Analyses evaluated potential tube shapes for improving the thermal performance of the LCVG. The analysis results fed into the selection of flat flow strips to improve thermal contact with the skin of the suited test subject. Testing of small segments was performed to compare thermal performance of the tubing approach of the current LCVG to the flat flow strips proposed as the new concept. Results of the testing is presented along with recommendations for future development of this new concept.

  3. High performance oilfield scale inhibitors

    SciTech Connect

    Duccini, Y.; Dufour, A.; Hann, W.M.; Sanders, T.W.; Weinstein, B.

    1997-08-01

    Sea water often reacts with the formation water in offshore fields to produce barium, calcium and strontium sulfate deposits that hinder oil production. Newer fields often have more difficult to control scale problems than older ones, and current technology scale inhibitors are not able to control the deposits as well as needed. In addition, ever more stringent regulations designed to minimize the impact of inhibitors on the environment are being enacted. Three new inhibitors are presented that overcome many of the problems of older technology scale inhibitors.

  4. Feedback control laws for highly maneuverable aircraft

    NASA Technical Reports Server (NTRS)

    Garrard, William L.; Balas, Gary J.

    1995-01-01

    During this year, we concentrated our efforts on the design of controllers for lateral/directional control using mu synthesis. This proved to be a more difficult task than we anticipated and we are still working on the designs. In the lateral-directional control problem, the inputs are pilot lateral stick and pedal commands and the outputs are roll rate about the velocity vector and side slip angle. The control effectors are ailerons, rudder deflection, and directional thrust vectoring vane deflection which produces a yawing moment about the body axis. Our math model does not contain any provision for thrust vectoring of rolling moment. This has resulted in limitations of performance at high angles of attack. During 1994-95, the following tasks for the lateral-directional controllers were accomplished: (1) Designed both inner and outer loop dynamic inversion controllers. These controllers are implemented using accelerometer outputs rather than an a priori model of the vehicle aerodynamics; (2) Used classical techniques to design controllers for the system linearized by dynamics inversion. These controllers acted to control roll rate and Dutch roll response; (3) Implemented the inner loop dynamic inversion and classical controllers on the six DOF simulation; (4) Developed a lateral-directional control allocation scheme based on minimizing required control effort among the ailerons, rudder, and directional thrust vectoring; and (5) Developed mu outer loop controllers combined with classical inner loop controllers.

  5. Control of household refrigerators. Part 1: Modeling temperature control performance

    SciTech Connect

    Graviss, K.J.; Collins, R.L.

    1999-07-01

    Commercial household refrigerators use simple, cost-effective, temperature controllers to obtain acceptable control. A manually adjusted airflow damper regulates the freezer compartment temperature while a thermostat controls operation of the compressor and evaporator fan to regulate refrigerator compartment temperature. Dual compartment temperature control can be achieved with automatic airflow dampers that function independently of the compressor and evaporator fan thermostat, resulting in improved temperature control quality and energy consumption. Under dual control, freezer temperature is controlled by the thermostat while the damper controls refrigerator temperature by regulating airflow circulation. A simulation model is presented that analyzes a household refrigerator configured with a conventional thermostat and both manual and automatic dampers. The model provides a new paradigm for investigating refrigerator systems and temperature control performance relative to the extensive verification testing that is typically done by manufacturers. The effects of each type of control and damper configuration are compared with respect to energy usage, control quality, and ambient temperature shift criteria. The results indicate that the appropriate control configuration can have significant effects and can improve plant performance.

  6. A high performance thermoacoustic engine

    NASA Astrophysics Data System (ADS)

    Tijani, M. E. H.; Spoelstra, S.

    2011-11-01

    In thermoacoustic systems heat is converted into acoustic energy and vice versa. These systems use inert gases as working medium and have no moving parts which makes the thermoacoustic technology a serious alternative to produce mechanical or electrical power, cooling power, and heating in a sustainable and environmentally friendly way. A thermoacoustic Stirling heat engine is designed and built which achieves a record performance of 49% of the Carnot efficiency. The design and performance of the engine is presented. The engine has no moving parts and is made up of few simple components.

  7. High-performance composite chocolate

    NASA Astrophysics Data System (ADS)

    Dean, Julian; Thomson, Katrin; Hollands, Lisa; Bates, Joanna; Carter, Melvyn; Freeman, Colin; Kapranos, Plato; Goodall, Russell

    2013-07-01

    The performance of any engineering component depends on and is limited by the properties of the material from which it is fabricated. It is crucial for engineering students to understand these material properties, interpret them and select the right material for the right application. In this paper we present a new method to engage students with the material selection process. In a competition-based practical, first-year undergraduate students design, cost and cast composite chocolate samples to maximize a particular performance criterion. The same activity could be adapted for any level of education to introduce the subject of materials properties and their effects on the material chosen for specific applications.

  8. Doping control analysis of 46 polar drugs in horse plasma and urine using a 'dilute-and-shoot' ultra high performance liquid chromatography-high resolution mass spectrometry approach.

    PubMed

    Kwok, Wai Him; Choi, Timmy L S; Kwok, Karen Y; Chan, George H M; Wong, Jenny K Y; Wan, Terence S M

    2016-06-17

    The high sensitivity of ultra high performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS) allows the identification of many prohibited substances without pre-concentration, leading to the development of simple and fast 'dilute-and-shoot' methods for doping control for human and equine sports. While the detection of polar drugs in plasma and urine is difficult using liquid-liquid or solid-phase extraction as these substances are poorly extracted, the 'dilute-and-shoot' approach is plausible. This paper describes a 'dilute-and-shoot' UHPLC-HRMS screening method to detect 46 polar drugs in equine urine and plasma, including some angiotensin-converting enzyme (ACE) inhibitors, sympathomimetics, anti-epileptics, hemostatics, the new doping agent 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), as well as two threshold substances, namely dimethyl sulfoxide and theobromine. For plasma, the sample (200μL) was protein precipitated using trichloroacetic acid, and the resulting supernatant was diluted using Buffer A with an overall dilution factor of 3. For urine, the sample (20μL) was simply diluted 50-fold with Buffer A. The diluted plasma or urine sample was then analysed using a UHPLC-HRMS system in full-scan ESI mode. The assay was validated for qualitative identification purpose. This straightforward and reliable approach carried out in combination with other screening procedures has increased the efficiency of doping control analysis in the laboratory. Moreover, since the UHPLC-HRMS data were acquired in full-scan mode, the method could theoretically accommodate an unlimited number of existing and new doping agents, and would allow a retrospectively search for drugs that have not been targeted at the time of analysis. PMID:27180888

  9. Influence of the sample toxic profile on the suitability of a high performance liquid chromatography method for official paralytic shellfish toxins control.

    PubMed

    Ben-Gigirey, B; Rodríguez-Velasco, M L; Villar-González, A; Botana, L M

    2007-01-26

    An HPLC-FLD method, involving pre-chromatographic oxidation of the PSP toxins with hydrogen peroxide and periodate, has been AOAC validated through a collaborative trial and adopted as AOAC Official Method. This method could be a candidate for replacing the mouse bioassay (MBA) for the Official Control of PSP toxins at European level, once accepted by the legislation. An interlaboratory exercise has been organized by the CRLMB to evaluate its "fitness for purpose" for the Official Control of PSP toxins in the EU laboratories. Eighteen EU laboratories took part in the study and had to analyze six bivalve mollusc samples with several PSP toxic profiles. The performance of the participant laboratories in the application of this method was compared with that obtained at the collaborative trial. Information on problems/drawbacks encountered by participants in the application of this method was also sought. The HPLC validated method is only applicable for Official PSP Control for certain samples. This depends on sample PSP toxic profile. Results obtained for samples where only GTX2,3 and STX were present were satisfactory and in agreement with MBA results. Results obtained for a sample with a toxic profile dominated by GTX6 and suspected to contain also C1,2 and C3,4 were not satisfactory. GTX5 and dc-STX could be quantified, although the results achieved (total toxicity) were lower than those obtained by MBA. It can be also useful as a screening method, complementary to MBA, helping in the reduction of the animals used. However, the lack of several PSP standards, the fact that the method is not validated for all the PSP toxins, and several drawbacks found in its application are a handicap to fully implement it for Official PSP Control as a viable replacement for bioassay.

  10. Toward High-Performance Organizations.

    ERIC Educational Resources Information Center

    Lawler, Edward E., III

    2002-01-01

    Reviews management changes that companies have made over time in adopting or adapting four approaches to organizational performance: employee involvement, total quality management, re-engineering, and knowledge management. Considers future possibilities and defines a new view of what constitutes effective organizational design in management.…

  11. High-Performance Composite Chocolate

    ERIC Educational Resources Information Center

    Dean, Julian; Thomson, Katrin; Hollands, Lisa; Bates, Joanna; Carter, Melvyn; Freeman, Colin; Kapranos, Plato; Goodall, Russell

    2013-01-01

    The performance of any engineering component depends on and is limited by the properties of the material from which it is fabricated. It is crucial for engineering students to understand these material properties, interpret them and select the right material for the right application. In this paper we present a new method to engage students with…

  12. High performance, high density hydrocarbon fuels

    NASA Technical Reports Server (NTRS)

    Frankenfeld, J. W.; Hastings, T. W.; Lieberman, M.; Taylor, W. F.

    1978-01-01

    The fuels were selected from 77 original candidates on the basis of estimated merit index and cost effectiveness. The ten candidates consisted of 3 pure compounds, 4 chemical plant streams and 3 refinery streams. Critical physical and chemical properties of the candidate fuels were measured including heat of combustion, density, and viscosity as a function of temperature, freezing points, vapor pressure, boiling point, thermal stability. The best all around candidate was found to be a chemical plant olefin stream rich in dicyclopentadiene. This material has a high merit index and is available at low cost. Possible problem areas were identified as low temperature flow properties and thermal stability. An economic analysis was carried out to determine the production costs of top candidates. The chemical plant and refinery streams were all less than 44 cent/kg while the pure compounds were greater than 44 cent/kg. A literature survey was conducted on the state of the art of advanced hydrocarbon fuel technology as applied to high energy propellents. Several areas for additional research were identified.

  13. THE SNS RESONANCE CONTROL COOLING SYSTEM CONTROL VALVE UPGRADE PERFORMANCE

    SciTech Connect

    Williams, Derrick C; Schubert, James Phillip; Tang, Johnny Y

    2008-01-01

    The normal-conducting linac of the Spallation Neutron Source (SNS) uses 10 separate Resonance Control Cooling System (RCCS) water skids to control the resonance of 6 Drift Tube Linac (DTL) and 4 Coupled Cavity Linac (CCL) accelerating structures. The RCCS water skids use 2 control valves; one to regulate the chilled water flow and the other to bypass water to a chilled water heat exchanger. These valves have hydraulic actuators that provide position and feedback to the control system. Frequency oscillations occur using these hydraulic actuators due to their coarse movement and control of the valves. New pneumatic actuator and control positioners have been installed on the DTL3 RCCS water skid to give finer control and regulation of DTL3 cavity temperature. This paper shows a comparison of resonance control performance for the two valve configurations.

  14. Joint Strength Control at the Fiber/Matrix Interface during the Production of Polymer Composite Materials Reinforced with High Performance Fibers

    NASA Astrophysics Data System (ADS)

    Kudinov, Vladimir V.; Korneeva, Natalia V.

    2010-06-01

    The paper presents the results obtained in the study of the joint strength between polymer matrix and high performance polyethylene fiber. The fiber/matrix joints simulate the unit cell of the fiber-reinforced composite materials. Effect of heat treatment on the composite properties at the interface was estimated by a multifilament wet-pull-out method. It was found that the joint strength may be increased with the help of extra heart treatment. Both the energy to peak load and the energy to failure for CM joints at various stages of loading were determined.

  15. High Performance Commercial Fenestration Framing Systems

    SciTech Connect

    Mike Manteghi; Sneh Kumar; Joshua Early; Bhaskar Adusumalli

    2010-01-31

    A major objective of the U.S. Department of Energy is to have a zero energy commercial building by the year 2025. Windows have a major influence on the energy performance of the building envelope as they control over 55% of building energy load, and represent one important area where technologies can be developed to save energy. Aluminum framing systems are used in over 80% of commercial fenestration products (i.e. windows, curtain walls, store fronts, etc.). Aluminum framing systems are often required in commercial buildings because of their inherent good structural properties and long service life, which is required from commercial and architectural frames. At the same time, they are lightweight and durable, requiring very little maintenance, and offer design flexibility. An additional benefit of aluminum framing systems is their relatively low cost and easy manufacturability. Aluminum, being an easily recyclable material, also offers sustainable features. However, from energy efficiency point of view, aluminum frames have lower thermal performance due to the very high thermal conductivity of aluminum. Fenestration systems constructed of aluminum alloys therefore have lower performance in terms of being effective barrier to energy transfer (heat loss or gain). Despite the lower energy performance, aluminum is the choice material for commercial framing systems and dominates the commercial/architectural fenestration market because of the reasons mentioned above. In addition, there is no other cost effective and energy efficient replacement material available to take place of aluminum in the commercial/architectural market. Hence it is imperative to improve the performance of aluminum framing system to improve the energy performance of commercial fenestration system and in turn reduce the energy consumption of commercial building and achieve zero energy building by 2025. The objective of this project was to develop high performance, energy efficient commercial

  16. Controlling human fixed-interval performance.

    PubMed

    Weiner, H

    1969-05-01

    Both high and relatively constant rates of responding without post-reinforcement pauses and lower rates with pauses after reinforcement are produced by human subjects under fixed-interval (FI) schedules. Such FI rates and patterns may be controlled when subjects are provided with different histories of conditioning and different conditions of response cost (reinforcement penalties per response). Subjects with a conditioning history under ratio schedules typically produce high and relatively constant rates of responding under FI schedules; this responding does not change systematically with changes in FI value. In contrast, subjects with a history under schedules which produce little or no responding between reforcements [such as differential-reinforcement-of-low-rate (DRL) schedules] tend to pause after reinforcement and respond at low rates under FI schedules, whether or not they also have ratio conditioning histories; cost increases the likelihood of this type of performance. For DRL-history subjects, post-reinforcement pauses increase and response rates decrease as FI values increase.

  17. Carpet Aids Learning in High Performance Schools

    ERIC Educational Resources Information Center

    Hurd, Frank

    2009-01-01

    The Healthy and High Performance Schools Act of 2002 has set specific federal guidelines for school design, and developed a federal/state partnership program to assist local districts in their school planning. According to the Collaborative for High Performance Schools (CHPS), high-performance schools are, among other things, healthy, comfortable,…

  18. High-Performance Miniature Hygrometer

    NASA Technical Reports Server (NTRS)

    Van Zandt, Thomas R.; Kaiser, William J.; Kenny, Thomas W.; Crisp, David

    1994-01-01

    Relatively inexpensive hygrometer that occupies volume less than 4 in.(3) measures dewpoints as much as 100 degrees C below ambient temperatures, with accuracy of 0.1 degrees C. Field tests indicate accuracy and repeatability identical to those of state-of-the-art larger dewpoint hygrometers. Operates up to 100 times as fast as older hygrometers, and offers simplicity and small size needed to meet cost and performance requirements of many applications.

  19. High-performance solar collector

    NASA Technical Reports Server (NTRS)

    Beekley, D. C.; Mather, G. R., Jr.

    1979-01-01

    Evacuated all-glass concentric tube collector using air or liquid transfer mediums is very efficient at high temperatures. Collector can directly drive existing heating systems that are presently driven by fossil fuel with relative ease of conversion and less expense than installation of complete solar heating systems.

  20. Solar Sail Attitude Control Performance Comparison

    NASA Technical Reports Server (NTRS)

    Bladt, Jeff J.; Lawrence, Dale A.

    2005-01-01

    Performance of two solar sail attitude control implementations is evaluated. One implementation employs four articulated reflective vanes located at the periphery of the sail assembly to generate control torque about all three axes. A second attitude control configuration uses mass on a gimbaled boom to alter the center-of-mass location relative to the center-of-pressure producing roll and pitch torque along with a pair of articulated control vanes for yaw control. Command generation algorithms employ linearized dynamics with a feedback inversion loop to map desired vehicle attitude control torque into vane and/or gimbal articulation angle commands. We investigate the impact on actuator deflection angle behavior due to variations in how the Jacobian matrix is incorporated into the feedback inversion loop. Additionally, we compare how well each implementation tracks a commanded thrust profile, which has been generated to follow an orbit trajectory from the sun-earth L1 point to a sub-L1 station.

  1. Novel high performance multispectral photodetector and its performance

    NASA Astrophysics Data System (ADS)

    Mizuno, Genki; Dutta, Jaydeep; Oduor, Patrick; Dutta, Achyut K.; Dhar, Nibir K.

    2016-05-01

    Banpil Photonics has developed a novel high-performance multispectral photodetector array for Short-Wave Infrared (SWIR) imaging. The InGaAs based device uses a unique micro-nano pillar structure that eliminates surface reflection to significantly increase sensitivity and the absorption spectra compared to its macro-scaled thin film pixels counterpart (non-pillar). We discuss the device structure and highlight fabrication of the novel high performance multispectral image sensor. We also present performance results of the device characterization showing low dark current suitable for high performance imaging applications for the most demanding security, defense, and machine vision applications.

  2. Thermal control surfaces experiment flight system performance

    NASA Technical Reports Server (NTRS)

    Wilkes, Donald R.; Hummer, Leigh L.; Zwiener, James M.

    1991-01-01

    The Thermal Control Surfaces Experiment (TCSE) is the most complex system, other than the LDEF, retrieved after long term space exposure. The TCSE is a microcosm of complex electro-optical payloads being developed and flow by NASA and the DoD including SDI. The objective of TCSE was to determine the effects of the near-Earth orbital environment and the LDEF induced environment on spacecraft thermal control surfaces. The TCSE was a comprehensive experiment that combined in-space measurements with extensive post flight analyses of thermal control surfaces to determine the effects of exposure to the low earth orbit space environment. The TCSE was the first space experiment to measure the optical properties of thermal control surfaces the way they are routinely measured in a lab. The performance of the TCSE confirms that low cost, complex experiment packages can be developed that perform well in space.

  3. High-performance liquid chromatography.

    PubMed

    Clevett, K J

    1990-01-01

    Gas chromatography has developed over the past 25 years or so into one of the most extensively used on-line analytical techniques in industrial process control and optimization. Liquid chromatography, and its several individual techniques, is firmly established in the laboratory, but its on-line process use has not developed as rapidly as GC. At the present time, only three companies (Applied Automation Inc., Dionex Corp., and Millipore Corp.) are active in this area. Nevertheless, substantial growth in on-line process LC is predicted for the next few years. The techniques of HPLC (normal-phase and reversed-phase), IEC, and SEC have great potential in industry as on-line analytical techniques, including the new field of biotechnology. Computer-based, multistream, multicomponent systems should find extensive use in pilot-plant investigations, where their ability to gather large amounts of data (on-line rather than by laboratory testing) could have important implications. In bioprocess control, undoubtedly the greatest challenge will come in the area of sample-handling technique. On-line chromatography has traditionally involved the sampling and conditioning of fairly conventional process gases and liquids. One exception is in the plastics and elastomers areas, where on-line SEC has been used for polymer MWD measurement. Here the sample is more difficult to handle, and some specialized techniques have been used. In biotechnology, we are treading new ground; nevertheless, it is hoped that some of the experience in sample handling gained in industry over the past 25 years will be of use in this new field.

  4. High-Performance LiNi0.5Mn1.5O4 Spinel Controlled by Mn3+ Concentration and Site Disorder

    SciTech Connect

    Xiao, Jie; Chen, Xilin; Sushko, P. V.; Sushko, Maria L.; Kovarik, Libor; Feng, Jijun; Deng, Zhiqun; Zheng, Jianming; Graff, Gordon L.; Nie, Zimin; Choi, Daiwon; Liu, Jun; Zhang, Jiguang; Whittingham, M. S.

    2012-03-19

    The influences of Mn3+ ions on the properties of high voltage spinel LiNi0.5Mn1.5O4 is systematically investigated in this work. The content of Mn3+ ions in the spinel is tuned by further annealing of the sample or partially substitution of Ni2+ in the lattice structure. The former decreases the amount of Mn3+ while the latter increases Mn3+ concentration, which has been confirmed by both X-ray diffraction (XRD) and electron diffraction analysis. It has also been experimentally and theoretically proven that Mn3+ ions are directly related to the disordering between Ni2+ and Mn4+ on the octahedral sites in the spinel structure which facilitates the transportation of Li+ ions especially at elevated current densities. An extremely cycling stability as well as good rate capability have been observed in the Cr-substituted spinel confirming that an appropriate amount of Mn3+ ions is the key for a high performance high voltage spinel.

  5. High performance rotational vibration isolator.

    PubMed

    Sunderland, Andrew; Blair, David G; Ju, Li; Golden, Howard; Torres, Francis; Chen, Xu; Lockwood, Ray; Wolfgram, Peter

    2013-10-01

    We present a new rotational vibration isolator with an extremely low resonant frequency of 0.055 ± 0.002 Hz. The isolator consists of two concentric spheres separated by a layer of water and joined by very soft silicone springs. The isolator reduces rotation noise at all frequencies above its resonance which is very important for airborne mineral detection. We show that more than 40 dB of isolation is achieved in a helicopter survey for rotations at frequencies between 2 Hz and 20 Hz. Issues affecting performance such as translation to rotation coupling and temperature are discussed. The isolator contains almost no metal, making it particularly suitable for electromagnetic sensors.

  6. Performance measurement: A tool for program control

    NASA Technical Reports Server (NTRS)

    Abell, Nancy

    1994-01-01

    Performance measurement is a management tool for planning, monitoring, and controlling as aspects of program and project management--cost, schedule, and technical requirements. It is a means (concept and approach) to a desired end (effective program planning and control). To reach the desired end, however, performance measurement must be applied and used appropriately, with full knowledge and recognition of its power and of its limitations--what it can and cannot do for the project manager. What is the potential of this management tool? What does performance measurement do that a traditional plan vs. actual technique cannot do? Performance measurement provides an improvement over the customary comparison of how much money was spent (actual cost) vs. how much was planned to be spent based on a schedule of activities (work planned). This commonly used plan vs. actual comparison does not allow one to know from the numerical data if the actual cost incurred was for work intended to be done.

  7. Effects of Sprint versus High-Intensity Aerobic Interval Training on Cross-Country Mountain Biking Performance: A Randomized Controlled Trial

    PubMed Central

    Inoue, Allan; Impellizzeri, Franco M.; Pires, Flávio O.; Pompeu, Fernando A. M. S.; Deslandes, Andrea C.; Santos, Tony M.

    2016-01-01

    Objectives The current study compared the effects of high-intensity aerobic training (HIT) and sprint interval training (SIT) on mountain biking (MTB) race simulation performance and physiological variables, including peak power output (PPO), lactate threshold (LT) and onset of blood lactate accumulation (OBLA). Methods Sixteen mountain bikers (mean ± SD: age 32.1 ± 6.4 yr, body mass 69.2 ± 5.3 kg and VO2max 63.4 ± 4.5 mL∙kg-1∙min-1) completed graded exercise and MTB performance tests before and after six weeks of training. The HIT (7–10 x [4–6 min—highest sustainable intensity / 4–6 min—CR100 10–15]) and SIT (8–12 x [30 s—all-out intensity / 4 min—CR100 10–15]) protocols were included in the participants’ regular training programs three times per week. Results Post-training analysis showed no significant differences between training modalities (HIT vs. SIT) in body mass, PPO, LT or OBLA (p = 0.30 to 0.94). The Cohen’s d effect size (ES) showed trivial to small effects on group factor (p = 0.00 to 0.56). The interaction between MTB race time and training modality was almost significant (p = 0.08), with a smaller ES in HIT vs. SIT training (ES = -0.43). A time main effect (pre- vs. post-phases) was observed in MTB race performance and in several physiological variables (p = 0.001 to 0.046). Co-variance analysis revealed that the HIT (p = 0.043) group had significantly better MTB race performance measures than the SIT group. Furthermore, magnitude-based inferences showed HIT to be of likely greater benefit (83.5%) with a lower probability of harmful effects (0.8%) compared to SIT. Conclusion The results of the current study suggest that six weeks of either HIT or SIT may be effective at increasing MTB race performance; however, HIT may be a preferable strategy. Trial Registration ClinicalTrials.gov NCT01944865 PMID:26789124

  8. Highly dispersed Co0.5Zn0.5Fe2O4/polypyrrole nanocomposites for cost-effective, high-performance defluoridation using a magnetically controllable microdevice.

    PubMed

    Wang, Gang; Shi, Guoying; Mu, Qinghui; Zhang, Qinghong; Wang, Hongzhi; Li, Yaogang

    2012-10-30

    Highly dispersed Co(0.5)Zn(0.5)Fe(2)O(4)/polypyrrole (CZFO/PPy) nanocomposites with enhanced electromagnetic properties and large surface area were rapidly and controllably prepared using microfluidic reactors. A novel magnetically controllable microdevice using the new adsorbent in a highly dispersed form was assembled and used for fluoride adsorption. Compared with traditional adsorption methods, the device displayed high adsorption efficiency and capacity. The adsorbents were regenerated with no significant loss in defluoridation ability, which indicates that the device is a realistic and highly efficient alternative way of removing fluoride pollution at low cost. PMID:22959477

  9. Automatic Energy Schemes for High Performance Applications

    SciTech Connect

    Sundriyal, Vaibhav

    2013-01-01

    Although high-performance computing traditionally focuses on the efficient execution of large-scale applications, both energy and power have become critical concerns when approaching exascale. Drastic increases in the power consumption of supercomputers affect significantly their operating costs and failure rates. In modern microprocessor architectures, equipped with dynamic voltage and frequency scaling (DVFS) and CPU clock modulation (throttling), the power consumption may be controlled in software. Additionally, network interconnect, such as Infiniband, may be exploited to maximize energy savings while the application performance loss and frequency switching overheads must be carefully balanced. This work first studies two important collective communication operations, all-to-all and allgather and proposes energy saving strategies on the per-call basis. Next, it targets point-to-point communications to group them into phases and apply frequency scaling to them to save energy by exploiting the architectural and communication stalls. Finally, it proposes an automatic runtime system which combines both collective and point-to-point communications into phases, and applies throttling to them apart from DVFS to maximize energy savings. The experimental results are presented for NAS parallel benchmark problems as well as for the realistic parallel electronic structure calculations performed by the widely used quantum chemistry package GAMESS. Close to the maximum energy savings were obtained with a substantially low performance loss on the given platform.

  10. Simultaneous quantification of the major bile acids in artificial Calculus bovis by high-performance liquid chromatography with precolumn derivatization and its application in quality control.

    PubMed

    Shi, Yan; Xiong, Jing; Sun, Dongmei; Liu, Wei; Wei, Feng; Ma, Shuangcheng; Lin, Ruichao

    2015-08-01

    An accurate and sensitive high-performance liquid chromatography method coupled with ultralviolet detection and precolumn derivatization was developed for the simultaneous quantification of the major bile acids in Artificial Calculus bovis, including cholic acid, hyodeoxycholic acid, chenodeoxycholic acid, and deoxycholic acid. The extraction, derivatization, chromatographic separation, and detection parameters were fully optimized. The samples were extracted with methanol by ultrasonic extraction. Then, 2-bromine-4'-nitroacetophenone and 18-crown ether-6 were used for derivatization. The chromatographic separation was performed on an Agilent SB-C18 column (250 × 4.6 mm id, 5 μm) at a column temperature of 30°C and liquid flow rate of 1.0 mL/min using water and methanol as the mobile phase with a gradient elution. The detection wavelength was 263 nm. The method was extensively validated by evaluating the linearity (r(2) ≥ 0.9980), recovery (94.24-98.91%), limits of detection (0.25-0.31 ng) and limits of quantification (0.83-1.02 ng). Seventeen samples were analyzed using the developed and validated method. Then, the amounts of bile acids were analyzed by hierarchical agglomerative clustering analysis and principal component analysis. The results of the chemometric analysis showed that the contents of these compounds reflect the intrinsic quality of artificial Calculus bovis, and two compounds (hyodeoxycholic acid and chenodeoxycholic acid) were the most important markers for quality evaluating. PMID:26016891

  11. Simultaneous quantification of the major bile acids in artificial Calculus bovis by high-performance liquid chromatography with precolumn derivatization and its application in quality control.

    PubMed

    Shi, Yan; Xiong, Jing; Sun, Dongmei; Liu, Wei; Wei, Feng; Ma, Shuangcheng; Lin, Ruichao

    2015-08-01

    An accurate and sensitive high-performance liquid chromatography method coupled with ultralviolet detection and precolumn derivatization was developed for the simultaneous quantification of the major bile acids in Artificial Calculus bovis, including cholic acid, hyodeoxycholic acid, chenodeoxycholic acid, and deoxycholic acid. The extraction, derivatization, chromatographic separation, and detection parameters were fully optimized. The samples were extracted with methanol by ultrasonic extraction. Then, 2-bromine-4'-nitroacetophenone and 18-crown ether-6 were used for derivatization. The chromatographic separation was performed on an Agilent SB-C18 column (250 × 4.6 mm id, 5 μm) at a column temperature of 30°C and liquid flow rate of 1.0 mL/min using water and methanol as the mobile phase with a gradient elution. The detection wavelength was 263 nm. The method was extensively validated by evaluating the linearity (r(2) ≥ 0.9980), recovery (94.24-98.91%), limits of detection (0.25-0.31 ng) and limits of quantification (0.83-1.02 ng). Seventeen samples were analyzed using the developed and validated method. Then, the amounts of bile acids were analyzed by hierarchical agglomerative clustering analysis and principal component analysis. The results of the chemometric analysis showed that the contents of these compounds reflect the intrinsic quality of artificial Calculus bovis, and two compounds (hyodeoxycholic acid and chenodeoxycholic acid) were the most important markers for quality evaluating.

  12. High performance electromagnetic simulation tools

    NASA Astrophysics Data System (ADS)

    Gedney, Stephen D.; Whites, Keith W.

    1994-10-01

    Army Research Office Grant #DAAH04-93-G-0453 has supported the purchase of 24 additional compute nodes that were installed in the Intel iPsC/860 hypercube at the Univesity Of Kentucky (UK), rendering a 32-node multiprocessor. This facility has allowed the investigators to explore and extend the boundaries of electromagnetic simulation for important areas of defense concerns including microwave monolithic integrated circuit (MMIC) design/analysis and electromagnetic materials research and development. The iPSC/860 has also provided an ideal platform for MMIC circuit simulations. A number of parallel methods based on direct time-domain solutions of Maxwell's equations have been developed on the iPSC/860, including a parallel finite-difference time-domain (FDTD) algorithm, and a parallel planar generalized Yee-algorithm (PGY). The iPSC/860 has also provided an ideal platform on which to develop a 'virtual laboratory' to numerically analyze, scientifically study and develop new types of materials with beneficial electromagnetic properties. These materials simulations are capable of assembling hundreds of microscopic inclusions from which an electromagnetic full-wave solution will be obtained in toto. This powerful simulation tool has enabled research of the full-wave analysis of complex multicomponent MMIC devices and the electromagnetic properties of many types of materials to be performed numerically rather than strictly in the laboratory.

  13. n-Type semiconducting naphthalene diimide-perylene diimide copolymers: controlling crystallinity, blend morphology, and compatibility toward high-performance all-polymer solar cells.

    PubMed

    Hwang, Ye-Jin; Earmme, Taeshik; Courtright, Brett A E; Eberle, Frank N; Jenekhe, Samson A

    2015-04-01

    Knowledge of the critical factors that determine compatibility, blend morphology, and performance of bulk heterojunction (BHJ) solar cells composed of an electron-accepting polymer and an electron-donating polymer remains limited. To test the idea that bulk crystallinity is such a critical factor, we have designed a series of new semiconducting naphthalene diimide (NDI)-selenophene/perylene diimide (PDI)-selenophene random copolymers, xPDI (10PDI, 30PDI, 50PDI), whose crystallinity varies with composition, and investigated them as electron acceptors in BHJ solar cells. Pairing of the reference crystalline (crystalline domain size Lc = 10.22 nm) NDI-selenophene copolymer (PNDIS-HD) with crystalline (Lc = 9.15 nm) benzodithiophene-thieno[3,4-b]thiophene copolymer (PBDTTT-CT) donor yields incompatible blends, whose BHJ solar cells have a power conversion efficiency (PCE) of 1.4%. However, pairing of the new 30PDI with optimal crystallinity (Lc = 5.11 nm) as acceptor with the same PBDTTT-CT donor yields compatible blends and all-polymer solar cells with enhanced performance (PCE = 6.3%, Jsc = 18.6 mA/cm(2), external quantum efficiency = 91%). These photovoltaic parameters observed in 30PDI:PBDTTT-CT devices are the best so far for all-polymer solar cells, while the short-circuit current (Jsc) and external quantum efficiency are even higher than reported values for [70]-fullerene:PBDTTT-CT solar cells. The morphology and bulk carrier mobilities of the polymer/polymer blends varied substantially with crystallinity of the acceptor polymer component and thus with the NDI/PDI copolymer composition. These results demonstrate that the crystallinity of a polymer component and thus compatibility, blend morphology, and efficiency of polymer/polymer blend solar cells can be controlled by molecular design.

  14. n-Type semiconducting naphthalene diimide-perylene diimide copolymers: controlling crystallinity, blend morphology, and compatibility toward high-performance all-polymer solar cells.

    PubMed

    Hwang, Ye-Jin; Earmme, Taeshik; Courtright, Brett A E; Eberle, Frank N; Jenekhe, Samson A

    2015-04-01

    Knowledge of the critical factors that determine compatibility, blend morphology, and performance of bulk heterojunction (BHJ) solar cells composed of an electron-accepting polymer and an electron-donating polymer remains limited. To test the idea that bulk crystallinity is such a critical factor, we have designed a series of new semiconducting naphthalene diimide (NDI)-selenophene/perylene diimide (PDI)-selenophene random copolymers, xPDI (10PDI, 30PDI, 50PDI), whose crystallinity varies with composition, and investigated them as electron acceptors in BHJ solar cells. Pairing of the reference crystalline (crystalline domain size Lc = 10.22 nm) NDI-selenophene copolymer (PNDIS-HD) with crystalline (Lc = 9.15 nm) benzodithiophene-thieno[3,4-b]thiophene copolymer (PBDTTT-CT) donor yields incompatible blends, whose BHJ solar cells have a power conversion efficiency (PCE) of 1.4%. However, pairing of the new 30PDI with optimal crystallinity (Lc = 5.11 nm) as acceptor with the same PBDTTT-CT donor yields compatible blends and all-polymer solar cells with enhanced performance (PCE = 6.3%, Jsc = 18.6 mA/cm(2), external quantum efficiency = 91%). These photovoltaic parameters observed in 30PDI:PBDTTT-CT devices are the best so far for all-polymer solar cells, while the short-circuit current (Jsc) and external quantum efficiency are even higher than reported values for [70]-fullerene:PBDTTT-CT solar cells. The morphology and bulk carrier mobilities of the polymer/polymer blends varied substantially with crystallinity of the acceptor polymer component and thus with the NDI/PDI copolymer composition. These results demonstrate that the crystallinity of a polymer component and thus compatibility, blend morphology, and efficiency of polymer/polymer blend solar cells can be controlled by molecular design. PMID:25807377

  15. An Associate Degree in High Performance Manufacturing.

    ERIC Educational Resources Information Center

    Packer, Arnold

    In order for more individuals to enter higher paying jobs, employers must create a sufficient number of high-performance positions (the demand side), and workers must acquire the skills needed to perform in these restructured workplaces (the supply side). Creating an associate degree in High Performance Manufacturing (HPM) will help address four…

  16. HIGH-PERFORMANCE COATING MATERIALS

    SciTech Connect

    SUGAMA,T.

    2007-01-01

    Corrosion, erosion, oxidation, and fouling by scale deposits impose critical issues in selecting the metal components used at geothermal power plants operating at brine temperatures up to 300 C. Replacing these components is very costly and time consuming. Currently, components made of titanium alloy and stainless steel commonly are employed for dealing with these problems. However, another major consideration in using these metals is not only that they are considerably more expensive than carbon steel, but also the susceptibility of corrosion-preventing passive oxide layers that develop on their outermost surface sites to reactions with brine-induced scales, such as silicate, silica, and calcite. Such reactions lead to the formation of strong interfacial bonds between the scales and oxide layers, causing the accumulation of multiple layers of scales, and the impairment of the plant component's function and efficacy; furthermore, a substantial amount of time is entailed in removing them. This cleaning operation essential for reusing the components is one of the factors causing the increase in the plant's maintenance costs. If inexpensive carbon steel components could be coated and lined with cost-effective high-hydrothermal temperature stable, anti-corrosion, -oxidation, and -fouling materials, this would improve the power plant's economic factors by engendering a considerable reduction in capital investment, and a decrease in the costs of operations and maintenance through optimized maintenance schedules.

  17. Study of High-Performance Coronagraphic Techniques

    NASA Astrophysics Data System (ADS)

    Tolls, Volker; Aziz, M. J.; Gonsalves, R. A.; Korzennik, S. G.; Labeyrie, A.; Lyon, R. G.; Melnick, G. J.; Somerstein, S.; Vasudevan, G.; Woodruff, R. A.

    2007-05-01

    We will provide a progress report about our study of high-performance coronagraphic techniques. At SAO we have set up a testbed to test coronagraphic masks and to demonstrate Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase or amplitude) and second occulter for speckle light suppression. The testbed consists of a coronagraph with high precision optics (2 inch spherical mirrors with lambda/1000 surface quality), lasers simulating the host star and the planet, and a single Labeyrie correction stage with a MEMS deformable mirror (DM) for the phase correction. The correction function is derived from images taken in- and slightly out-of-focus using phase diversity. The testbed is operational awaiting coronagraphic masks. The testbed control software for operating the CCD camera, the translation stage that moves the camera in- and out-of-focus, the wavefront recovery (phase diversity) module, and DM control is under development. We are also developing coronagraphic masks in collaboration with Harvard University and Lockheed Martin Corp. (LMCO). The development at Harvard utilizes a focused ion beam system to mill masks out of absorber material and the LMCO approach uses patterns of dots to achieve the desired mask performance. We will present results of both investigations including test results from the first generation of LMCO masks obtained with our high-precision mask scanner. This work was supported by NASA through grant NNG04GC57G, through SAO IR&D funding, and by Harvard University through the Research Experience for Undergraduate Program of Harvard's Materials Science and Engineering Center. Central facilities were provided by Harvard's Center for Nanoscale Systems.

  18. Performance of Personal Workspace Controls Final Report

    SciTech Connect

    Rubinstein, Francis; Kiliccote, Sila; Loffeld, John; Pettler,Pete; Snook, Joel

    2004-12-01

    One of the key deliverables for the DOE-funded controls research at LBNL for FY04 was the development of a prototype Personal Workspace Control system. The successful development of this system is a critical milestone for the LBNL Lighting Controls Research effort because this system demonstrates how IBECS can add value to today's Task Ambient lighting systems. LBNL has argued that by providing both the occupant and the facilities manager with the ability to precisely control the operation of overhead lighting and all task lighting in a coordinated manner, that task ambient lighting can optimize energy performance and occupant comfort simultaneously [Reference Task Ambient Foundation Document]. The Personal Workspace Control system is the application of IBECS to this important lighting problem. This report discusses the development of the Personal Workspace Control to date including descriptions of the different fixture types that have been converted to IBECS operation and a detailed description of the operation of PWC Scene Controller, which provides the end user with precise control of his task ambient lighting system. The objective, from the Annual Plan, is to demonstrate improvements in efficiency, lighting quality and occupant comfort realized using Personal Workspace Controls (PWC) designed to optimize the delivery of lighting to the individual's workstation regardless of which task-ambient lighting solution is chosen. The PWC will be capable of controlling floor-mounted, desk lamps, furniture-mounted and overhead lighting fixtures from a personal computer and handheld remote. The PWC will use an environmental sensor to automatically monitor illuminance, temperature and occupancy and to appropriately modulate ambient lighting according to daylight availability and to switch off task lighting according to local occupancy. [Adding occupancy control to the system would blunt the historical criticism of occupant-controlled lighting - the tendency of the occupant

  19. Rotordynamic Instability Problems in High-Performance Turbomachinery

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Rotor dynamic instability problems in high performance turbomachinery are reviewed. Mechanical instability mechanisms are discussed. Seal forces and working fluid forces in turbomachinery are discussed. Control of rotor instability is also investigated.

  20. Statistical properties of high performance cesium standards

    NASA Technical Reports Server (NTRS)

    Percival, D. B.

    1973-01-01

    The intermediate term frequency stability of a group of new high-performance cesium beam tubes at the U.S. Naval Observatory were analyzed from two viewpoints: (1) by comparison of the high-performance standards to the MEAN(USNO) time scale and (2) by intercomparisons among the standards themselves. For sampling times up to 5 days, the frequency stability of the high-performance units shows significant improvement over older commercial cesium beam standards.

  1. High performance amorphous selenium lateral photodetector

    NASA Astrophysics Data System (ADS)

    Abbaszadeh, Shiva; Allec, Nicholas; Karim, Karim S.

    2012-03-01

    Lateral amorphous selenium (a-Se) detectors based on the metal-semiconductor-metal (MSM) device structure have been studied for indirect detector medical imaging applications. These detectors have raised interest due to their simple structure, ease of fabrication, high-speed, low dark current, low capacitance per unit area and better light utilization. The lateral device structure has a benefit that the electrode spacing may be easily controlled to reduce the required bias for a given desired electric field. In indirect conversion x-ray imaging, the scintillator is coupled to the top of the a-Se MSM photodetector, which itself is integrated on top of the thin-film-transistor (TFT) array. The carriers generated at the top surface of the a-Se layer experience a field that is parallel to the surface, and does not initially sweep them away from the surface. Therefore these carriers may recombine or get trapped in surface states and change the field at the surface, which may degrade the performance of the photodetector. In addition, due to the finite width of the electrodes, the fill factor of the device is less than unity. In this study we examine the effect of lateral drift of carriers and the fill factor on the photodetector performance. The impact of field magnitude on the performance is also investigated.

  2. Frequency Control Performance Measurement and Requirements

    SciTech Connect

    Illian, Howard F.

    2010-12-20

    Frequency control is an essential requirement of reliable electric power system operations. Determination of frequency control depends on frequency measurement and the practices based on these measurements that dictate acceptable frequency management. This report chronicles the evolution of these measurements and practices. As technology progresses from analog to digital for calculation, communication, and control, the technical basis for frequency control measurement and practices to determine acceptable performance continues to improve. Before the introduction of digital computing, practices were determined largely by prior experience. In anticipation of mandatory reliability rules, practices evolved from a focus primarily on commercial and equity issues to an increased focus on reliability. This evolution is expected to continue and place increased requirements for more precise measurements and a stronger scientific basis for future frequency management practices in support of reliability.

  3. A General and Mild Approach to Controllable Preparation of Manganese-Based Micro- and Nanostructured Bars for High Performance Lithium-Ion Batteries.

    PubMed

    Ma, Guo; Li, Sheng; Zhang, Weixin; Yang, Zeheng; Liu, Shulin; Fan, Xiaoming; Chen, Fei; Tian, Yuan; Zhang, Weibo; Yang, Shihe; Li, Mei

    2016-03-01

    One-dimensional (1D) micro- and nanostructured electrode materials with controllable phase and composition are appealing materials for use in lithium-ion batteries with high energy and power densities, but they are challenging to prepare. Herein, a novel ethanol-water mediated co-precipitation method by a chimie douce route (synthesis conducted under mild conditions) has been exploited to selectively prepare an extensive series of manganese-based electrode materials, manifesting the considerable generalizability and efficacy of the method. Moreover, by simply tuning the mixed solvent and reagents, transition metal oxide bars with differing aspect ratios and compositions were prepared with an unprecedented uniformity. Application prospects are demonstrated by Li-rich 0.5 Li2 MnO3 ⋅0.5 LiNi1/3 Co1/3 Mn1/3 O2 bars, which demonstrate excellent reversible capacity and rate capability thanks to the steerable nature of the synthesis and material quality. This work opens a new route to 1D micro- and nanostructured materials by customizing the precipitating solvent to orchestrate the crystallization process.

  4. Energetic Salts Based on 3,5-Bis(dinitromethyl)-1,2,4-triazole Monoanion and Dianion: Controllable Preparation, Characterization, and High Performance.

    PubMed

    Zhang, Jiaheng; Dharavath, Srinivas; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2016-06-22

    Molecular modification of known explosives is considered to be an efficient route to design new energetic materials. A new family of energetic salts based on the 3,5-bis(dinitromethyl)-1,2,4-triazole monoanion and dianion were controllably synthesized by using 1-diamino-2,2-dinitroethene as a precursor. X-ray structure determination of monohydrazinium 3,5-bis(dinitromethyl)-1,2,4-triazolate (5) and monoammonium (6) and diammonium 3,5-bis(dinitromethyl)-1,2,4-triazolate hydrate (8·H2O) further confirmed the structures of these anions. In addition, as supported by X-ray data, in the monoanion system, the roving proton on the ring nitrogen rather than on the gem-dinitro carbon results in extensive hydrogen-bonding interactions and higher packing coefficients. Interestingly, 5 and 6 possess the highest calculated crystal densities, 1.965 and 1.957 g cm(-3) at 150 K, for hydrazinium and ammonium energetic salts, respectively. Energetic evaluation indicates that 5 (detonation velocity vD = 9086 m s(-1); detonation pressure P = 38.7 GPa) and 6 (vD, 9271 m s(-1); P = 41.0 GPa) exhibit great detonation properties, superior to those of current highly explosive benchmarks, such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). PMID:27267735

  5. Effects of high Zn and Pb concentrations on Phragmites australis (Cav.) Trin. Ex. Steudel: Photosynthetic performance and metal accumulation capacity under controlled conditions.

    PubMed

    Bernardini, A; Salvatori, E; Guerrini, V; Fusaro, L; Canepari, S; Manes, F

    2016-01-01

    The response of Phragmites australis (Cav.) Trin. Ex. Steudel to zinc (Zn) and lead (Pb) was studied separately in two hydroponic tests, during a three weeks experiment. The effects on ecophysiology and biomass partitioning were evaluated during the metal treatments and at the recovery, and total metal content and accumulation capacity in different plant organs were assessed. Zn and Pb had different effects on the overall measured parameters, highlighting different mechanism of action. In particular, Zn concentration was higher in roots and, being a micronutrient, it was translocated into leaves, producing a reduction of assimilation rate, stomatal conductance (-71.9 and -81.3% respect to the control plant respectively), and a strong down regulation of photosystems functionality both at PSII and PSI level. Otherwise, Pb was accumulated mainly in the more lignified tissue such as rhizomes, with slightly effect on gas exchange. Chlorophyll a fluorescence highlighted that Pb inhibits the electron transfer process at the PSI donor side, without recovery after the removal of the metal stress. Despite these physiological limitations, P. australis showed a high capacity to accumulate both metals, and only slight reduction of biomass, being therefore a suitable species for phytoremediation interventions.

  6. Energetic Salts Based on 3,5-Bis(dinitromethyl)-1,2,4-triazole Monoanion and Dianion: Controllable Preparation, Characterization, and High Performance.

    PubMed

    Zhang, Jiaheng; Dharavath, Srinivas; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2016-06-22

    Molecular modification of known explosives is considered to be an efficient route to design new energetic materials. A new family of energetic salts based on the 3,5-bis(dinitromethyl)-1,2,4-triazole monoanion and dianion were controllably synthesized by using 1-diamino-2,2-dinitroethene as a precursor. X-ray structure determination of monohydrazinium 3,5-bis(dinitromethyl)-1,2,4-triazolate (5) and monoammonium (6) and diammonium 3,5-bis(dinitromethyl)-1,2,4-triazolate hydrate (8·H2O) further confirmed the structures of these anions. In addition, as supported by X-ray data, in the monoanion system, the roving proton on the ring nitrogen rather than on the gem-dinitro carbon results in extensive hydrogen-bonding interactions and higher packing coefficients. Interestingly, 5 and 6 possess the highest calculated crystal densities, 1.965 and 1.957 g cm(-3) at 150 K, for hydrazinium and ammonium energetic salts, respectively. Energetic evaluation indicates that 5 (detonation velocity vD = 9086 m s(-1); detonation pressure P = 38.7 GPa) and 6 (vD, 9271 m s(-1); P = 41.0 GPa) exhibit great detonation properties, superior to those of current highly explosive benchmarks, such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).

  7. High performance carbon nanocomposites for ultracapacitors

    DOEpatents

    Lu, Wen

    2012-10-02

    The present invention relates to composite electrodes for electrochemical devices, particularly to carbon nanotube composite electrodes for high performance electrochemical devices, such as ultracapacitors.

  8. Method of making a high performance ultracapacitor

    DOEpatents

    Farahmandi, C. Joseph; Dispennette, John M.

    2000-07-26

    A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.

  9. Performance TTradeoffs in Distributed Control Systems

    NASA Astrophysics Data System (ADS)

    Borowski, Holly

    Large scale systems consisting of many interacting subsystems are often controlled in a distributed fashion due to inherent limitations in computation, communication, or sensing. Here, individual agents must make decisions based on local, often incomplete information. This dissertation focuses on understanding performance tradeoffs in distributed control systems, specifically focusing on using a game theoretic framework to assign agent control laws. Performance of a distributed control law is determined by (1) the degree with which it meets a stated objective, (2) the amount of time it takes to converge, (3) agents' informational requirements, and (4) vulnerability to adversarial manipulation. The three main research questions addressed in this work are: • When is fast convergence to near-optimal behavior possible in a distributed system? We design a distributed control law which converges to a near-optimal configuration in a time that is near-linear in the number of agents. This worst case convergence time is an improvement over existing algorithms whose worst-case convergence times are exponential in the number of agents. • Can agents in a distributed system learn near-optimal correlated behavior despite severely limited information about one another's behavior? We design a distributed control law that imposes limited informational requirements for individual agents and converges to near-optimal correlated behavior. • How does the structure of agent interaction impact a distributed control system's vulnerability to adversarial manipulation? We derive a graph theoretical condition that ensures resilience to adversarial manipulation, and we examine the conditions under which an adversary can manipulate collective behavior in a distributed control system, simply by influencing small subsets of agents.

  10. Performance of microprocessor controllers. Final report

    SciTech Connect

    Gates, R.S.; Turner, L.W.; Overhults, D.G.

    1992-01-01

    United States animal production systems are at the threshold of a major new method for daily management of environmental control -- the integrated microprocessor-based environmental control system. Widespread adoption of this technology has the potential for dramatic improvement in production efficiencies through lower management costs, improved energy savings, and better feed conversion efficiencies. However, the technical problems of transient surge protection and appropriate mechanical backup systems have not been adequately addressed by the industry. The goals of this research were to identify the degree to which transient surge protection was being provided by current manufacturers, and to illustrate the implementation of microprocessor environmental control systems with mechanical backup. Transient open circuit over-voltage tests (ANSI/IEEE C62.41-1980) were performed on 16 environmental control units: a maximum of 800 V spike was applied to the power supplies, and up to 100 V spike applied to temperature sensor lines. Under these relatively mild tests, no failures were noted due to power supply transients, but three units failed when subjected to transients on their temperature sensor lines. Mechanical backup systems were designed to provide essential life-support during critical conditions of extreme outside conditions and extreme animal densities. The design and installation of environmental control systems for (1) a gestation unit and (2) a broiler house was performed. An overview of the process, and difficulties noted, is presented. Both systems incorporated mechanical backups. 20 refs.

  11. Optimal performance of constrained control systems

    NASA Astrophysics Data System (ADS)

    Harvey, P. Scott, Jr.; Gavin, Henri P.; Scruggs, Jeffrey T.

    2012-08-01

    This paper presents a method to compute optimal open-loop trajectories for systems subject to state and control inequality constraints in which the cost function is quadratic and the state dynamics are linear. For the case in which inequality constraints are decentralized with respect to the controls, optimal Lagrange multipliers enforcing the inequality constraints may be found at any time through Pontryagin’s minimum principle. In so doing, the set of differential algebraic Euler-Lagrange equations is transformed into a nonlinear two-point boundary-value problem for states and costates whose solution meets the necessary conditions for optimality. The optimal performance of inequality constrained control systems is calculable, allowing for comparison to previous, sub-optimal solutions. The method is applied to the control of damping forces in a vibration isolation system subjected to constraints imposed by the physical implementation of a particular controllable damper. An outcome of this study is the best performance achievable given a particular objective, isolation system, and semi-active damper constraints.

  12. Orion Entry Flight Control Stability and Performance

    NASA Technical Reports Server (NTRS)

    Strahan, Alan L.; Loe, Greg R.; Seiler, Pete

    2007-01-01

    The Orion Spacecraft will be required to perform entry and landing functions for both Low Earth Orbit (LEO) and Lunar return missions, utilizing only the Command Module (CM) with its unique systems and GN&C design. This paper presents the current CM Flight Control System (FCS) design to support entry and landing, with a focus on analyses that have supported its development to date. The CM FCS will have to provide for spacecraft stability and control while following guidance or manual commands during exo-atmospheric flight, after Service Module separation, translational powered flight required of the CM, atmospheric flight supporting both direct entry and skip trajectories down to drogue chute deploy, and during roll attitude reorientation just prior to touchdown. Various studies and analyses have been performed or are on-going supporting an overall FCS design with reasonably sized Reaction Control System (RCS) jets, that minimizes fuel usage, that provides appropriate command following but with reasonable stability and control margin. Results from these efforts to date are included, with particular attention on design issues that have emerged, such as the struggle to accommodate sub-sonic pitch and yaw control without using excessively large jets that could have a detrimental impact on vehicle weight. Apollo, with a similar shape, struggled with this issue as well. Outstanding CM FCS related design and analysis issues, planned for future effort, are also briefly be discussed.

  13. Strategy Guideline: High Performance Residential Lighting

    SciTech Connect

    Holton, J.

    2012-02-01

    The Strategy Guideline: High Performance Residential Lighting has been developed to provide a tool for the understanding and application of high performance lighting in the home. The high performance lighting strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner's expectations for high quality lighting.

  14. Improving UV Resistance of High Performance Fibers

    NASA Astrophysics Data System (ADS)

    Hassanin, Ahmed

    % rutile TiO2 nanoparticles showed excellent protection of braid from PBO. Only 7.5% strength loss was observed. To optimize the degree of protection of the sheath loaded with UV blocker particles, computational models were developed to optimize the protective layer thickness/weight and the amount of UV particles that provide the maximum protection with lightest weight of the protective layer and minimum amount of UV particles. The simulated results were found to be higher that the experimental results due to the tendency of nanoparticles to be agglomerated in real experiments. The third approach to achieve a maximum protection with the minimum weight added is constructing a sleeve from SpectraRTM (Ultra High Molecular Weight Polyethylene (UHMWPE) high performance fiber), which is known to resist UV, woven fabric. Covering the braid from PBO fiber with Spectra RTM woven fabric provide hybrid structure with two compatible components that can share the load and thus maintain the high strength to weight ratio. Although the SpectraRTM fabric had maximum cover factor, 20 % of visible light and about 15 % of UV were able to penetrate the fabric. This transmittance of UV-VIS light negatively affected the protection performance of the SpectraRTM woven fabric layer. It is thought that SpectraRTM fabric be coated with a thin layer (mentioned earlier) containing UV blocker for additional protection while maintain strength contribution to the hybrid structure. To maximize the strength to weight ratio of the hybrid structure (with core from PBO braid and sheath from SpectraRTM woven fabric) an established finite element model was utilized. The theoretical results using the finite element theory indicated that by controlling the bending rigidity of the filling yarn of the SpectraRTM fabric, the extension at peak load of woven fabric in warp direction (loading direction) could be controlled to match the braid extension at peak load. The match in the extension at peak load of the two

  15. Integrating advanced facades into high performance buildings

    SciTech Connect

    Selkowitz, Stephen E.

    2001-05-01

    Glass is a remarkable material but its functionality is significantly enhanced when it is processed or altered to provide added intrinsic capabilities. The overall performance of glass elements in a building can be further enhanced when they are designed to be part of a complete facade system. Finally the facade system delivers the greatest performance to the building owner and occupants when it becomes an essential element of a fully integrated building design. This presentation examines the growing interest in incorporating advanced glazing elements into more comprehensive facade and building systems in a manner that increases comfort, productivity and amenity for occupants, reduces operating costs for building owners, and contributes to improving the health of the planet by reducing overall energy use and negative environmental impacts. We explore the role of glazing systems in dynamic and responsive facades that provide the following functionality: Enhanced sun protection and cooling load control while improving thermal comfort and providing most of the light needed with daylighting; Enhanced air quality and reduced cooling loads using natural ventilation schemes employing the facade as an active air control element; Reduced operating costs by minimizing lighting, cooling and heating energy use by optimizing the daylighting-thermal tradeoffs; Net positive contributions to the energy balance of the building using integrated photovoltaic systems; Improved indoor environments leading to enhanced occupant health, comfort and performance. In addressing these issues facade system solutions must, of course, respect the constraints of latitude, location, solar orientation, acoustics, earthquake and fire safety, etc. Since climate and occupant needs are dynamic variables, in a high performance building the facade solution have the capacity to respond and adapt to these variable exterior conditions and to changing occupant needs. This responsive performance capability

  16. Role of information systems in controlling costs: the electronic medical record (EMR) and the high-performance computing and communications (HPCC) efforts

    NASA Astrophysics Data System (ADS)

    Kun, Luis G.

    1994-12-01

    On October 18, 1991, the IEEE-USA produced an entity statement which endorsed the vital importance of the High Performance Computer and Communications Act of 1991 (HPCC) and called for the rapid implementation of all its elements. Efforts are now underway to develop a Computer Based Patient Record (CBPR), the National Information Infrastructure (NII) as part of the HPCC, and the so-called `Patient Card'. Multiple legislative initiatives which address these and related information technology issues are pending in Congress. Clearly, a national information system will greatly affect the way health care delivery is provided to the United States public. Timely and reliable information represents a critical element in any initiative to reform the health care system as well as to protect and improve the health of every person. Appropriately used, information technologies offer a vital means of improving the quality of patient care, increasing access to universal care and lowering overall costs within a national health care program. Health care reform legislation should reflect increased budgetary support and a legal mandate for the creation of a national health care information system by: (1) constructing a National Information Infrastructure; (2) building a Computer Based Patient Record System; (3) bringing the collective resources of our National Laboratories to bear in developing and implementing the NII and CBPR, as well as a security system with which to safeguard the privacy rights of patients and the physician-patient privilege; and (4) utilizing Government (e.g. DOD, DOE) capabilities (technology and human resources) to maximize resource utilization, create new jobs and accelerate technology transfer to address health care issues.

  17. Prospective Randomized Controlled Study on the Efficacy of Multimedia Informed Consent for Patients Scheduled to Undergo Green-Light High-Performance System Photoselective Vaporization of the Prostate

    PubMed Central

    Ham, Dong Yeub; Choi, Woo Suk; Song, Sang Hoon; Ahn, Young-Joon; Park, Hyoung Keun; Kim, Hyeong Gon

    2016-01-01

    Purpose The aim of this study was to evaluate the efficacy of a multimedia informed consent (IC) presentation on the understanding and satisfaction of patients who were scheduled to receive 120-W green-light high-performance system photoselective vaporization of the prostate (HPS-PVP). Materials and Methods A multimedia IC (M-IC) presentation for HPS-PVP was developed. Forty men with benign prostatic hyperplasia who were scheduled to undergo HPS-PVP were prospectively randomized to a conventional written IC group (W-IC group, n=20) or the M-IC group (n=20). The allocated IC was obtained by one certified urologist, followed by a 15-question test (maximum score, 15) to evaluate objective understanding, and questionnaires on subjective understanding (range, 0~10) and satisfaction (range, 0~10) using a visual analogue scale. Results Demographic characteristics, including age and the highest level of education, did not significantly differ between the two groups. No significant differences were found in scores reflecting the objective understanding of HPS-PVP (9.9±2.3 vs. 10.6±2.8, p=0.332) or in subjective understanding scores (7.5±2.1 vs. 8.6±1.7, p=0.122); however, the M-IC group showed higher satisfaction scores than the W-IC group (7.4±1.7 vs. 8.4±1.5, p=0.033). After adjusting for age and educational level, the M-IC group still had significantly higher satisfaction scores. Conclusions M-IC did not enhance the objective knowledge of patients regarding this surgical procedure. However, it improved the satisfaction of patients with the IC process itself. PMID:27169129

  18. Low-Cost High-Performance MRI.

    PubMed

    Sarracanie, Mathieu; LaPierre, Cristen D; Salameh, Najat; Waddington, David E J; Witzel, Thomas; Rosen, Matthew S

    2015-01-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5-3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm(3) imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices. PMID:26469756

  19. Low-Cost High-Performance MRI

    NASA Astrophysics Data System (ADS)

    Sarracanie, Mathieu; Lapierre, Cristen D.; Salameh, Najat; Waddington, David E. J.; Witzel, Thomas; Rosen, Matthew S.

    2015-10-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5-3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices.

  20. Team Development for High Performance Management.

    ERIC Educational Resources Information Center

    Schermerhorn, John R., Jr.

    1986-01-01

    The author examines a team development approach to management that creates shared commitments to performance improvement by focusing the attention of managers on individual workers and their task accomplishments. It uses the "high-performance equation" to help managers confront shared beliefs and concerns about performance and develop realistic…

  1. Common Factors of High Performance Teams

    ERIC Educational Resources Information Center

    Jackson, Bruce; Madsen, Susan R.

    2005-01-01

    Utilization of work teams is now wide spread in all types of organizations throughout the world. However, an understanding of the important factors common to high performance teams is rare. The purpose of this content analysis is to explore the literature and propose findings related to high performance teams. These include definition and types,…

  2. Properties Of High-Performance Thermoplastics

    NASA Technical Reports Server (NTRS)

    Johnston, Norman J.; Hergenrother, Paul M.

    1992-01-01

    Report presents review of principal thermoplastics (TP's) used to fabricate high-performance composites. Sixteen principal TP's considered as candidates for fabrication of high-performance composites presented along with names of suppliers, Tg, Tm (for semicrystalline polymers), and approximate maximum processing temperatures.

  3. Biotechnology-based odour control: design criteria and performance data.

    PubMed

    Quigley, C; Easter, C; Burrowes, P; Witherspoon, J

    2004-01-01

    As neighbouring areas continue to encroach upon wastewater treatment plants, there is an increasing need for odour control to mitigate potential negative offsite odorous impacts. One technology that is gaining widespread acceptance is biotechnology, which utilises the inherent ability of certain microorganisms to biodegrade offensive odorous compounds. Two main advantages of this form of treatment over other odour control technologies include the absence of hazardous chemicals and relatively low operation and maintenance requirements. The purpose of this paper is to provide information related to odour control design criteria used in sizing/selecting biotechnology-based odour control technologies, and to provide odour removal performance data obtained from several different biotechnology-based odour control systems. CH2M HILL has collected biotechnology-based odour control performance data over the last several years in order to track the continued performance of various biofilters and biotowers over time. Specifically, odour removal performance data have been collected from soil-, organic- and inorganic-media biofilters and inert inorganic media biotowers. Results indicate that biotechnology-based odour control is a viable and consistent technology capable of achieving high removal performance for odour and hydrogen sulphide. It is anticipated that the information presented in this paper will be of interest to anyone involved with odour control technology evaluation/selection or design review.

  4. Biotechnology-based odour control: design criteria and performance data.

    PubMed

    Quigley, C; Easter, C; Burrowes, P; Witherspoon, J

    2004-01-01

    As neighbouring areas continue to encroach upon wastewater treatment plants, there is an increasing need for odour control to mitigate potential negative offsite odorous impacts. One technology that is gaining widespread acceptance is biotechnology, which utilises the inherent ability of certain microorganisms to biodegrade offensive odorous compounds. Two main advantages of this form of treatment over other odour control technologies include the absence of hazardous chemicals and relatively low operation and maintenance requirements. The purpose of this paper is to provide information related to odour control design criteria used in sizing/selecting biotechnology-based odour control technologies, and to provide odour removal performance data obtained from several different biotechnology-based odour control systems. CH2M HILL has collected biotechnology-based odour control performance data over the last several years in order to track the continued performance of various biofilters and biotowers over time. Specifically, odour removal performance data have been collected from soil-, organic- and inorganic-media biofilters and inert inorganic media biotowers. Results indicate that biotechnology-based odour control is a viable and consistent technology capable of achieving high removal performance for odour and hydrogen sulphide. It is anticipated that the information presented in this paper will be of interest to anyone involved with odour control technology evaluation/selection or design review. PMID:15484776

  5. Scalable resource management in high performance computers.

    SciTech Connect

    Frachtenberg, E.; Petrini, F.; Fernandez Peinador, J.; Coll, S.

    2002-01-01

    Clusters of workstations have emerged as an important platform for building cost-effective, scalable and highly-available computers. Although many hardware solutions are available today, the largest challenge in making large-scale clusters usable lies in the system software. In this paper we present STORM, a resource management tool designed to provide scalability, low overhead and the flexibility necessary to efficiently support and analyze a wide range of job scheduling algorithms. STORM achieves these feats by closely integrating the management daemons with the low-level features that are common in state-of-the-art high-performance system area networks. The architecture of STORM is based on three main technical innovations. First, a sizable part of the scheduler runs in the thread processor located on the network interface. Second, we use hardware collectives that are highly scalable both for implementing control heartbeats and to distribute the binary of a parallel job in near-constant time, irrespective of job and machine sizes. Third, we use an I/O bypass protocol that allows fast data movements from the file system to the communication buffers in the network interface and vice versa. The experimental results show that STORM can launch a job with a binary of 12MB on a 64 processor/32 node cluster in less than 0.25 sec on an empty network, in less than 0.45 sec when all the processors are busy computing other jobs, and in less than 0.65 sec when the network is flooded with a background traffic. This paper provides experimental and analytical evidence that these results scale to a much larger number of nodes. To the best of our knowledge, STORM is at least two orders of magnitude faster than existing production schedulers in launching jobs, performing resource management tasks and gang scheduling.

  6. Adaptive Performance Seeking Control Using Fuzzy Model Reference Learning Control and Positive Gradient Control

    NASA Technical Reports Server (NTRS)

    Kopasakis, George

    1997-01-01

    Performance Seeking Control attempts to find the operating condition that will generate optimal performance and control the plant at that operating condition. In this paper a nonlinear multivariable Adaptive Performance Seeking Control (APSC) methodology will be developed and it will be demonstrated on a nonlinear system. The APSC is comprised of the Positive Gradient Control (PGC) and the Fuzzy Model Reference Learning Control (FMRLC). The PGC computes the positive gradients of the desired performance function with respect to the control inputs in order to drive the plant set points to the operating point that will produce optimal performance. The PGC approach will be derived in this paper. The feedback control of the plant is performed by the FMRLC. For the FMRLC, the conventional fuzzy model reference learning control methodology is utilized, with guidelines generated here for the effective tuning of the FMRLC controller.

  7. Advanced Noise Control Fan Aerodynamic Performance

    NASA Technical Reports Server (NTRS)

    Bozak, Richard F., Jr.

    2009-01-01

    The Advanced Noise Control Fan at the NASA Glenn Research Center is used to experimentally analyze fan generated acoustics. In order to determine how a proposed noise reduction concept affects fan performance, flow measurements can be used to compute mass flow. Since tedious flow mapping is required to obtain an accurate mass flow, an equation was developed to correlate the mass flow to inlet lip wall static pressure measurements. Once this correlation is obtained, the mass flow for future configurations can be obtained from the nonintrusive wall static pressures. Once the mass flow is known, the thrust and fan performance can be evaluated. This correlation enables fan acoustics and performance to be obtained simultaneously without disturbing the flow.

  8. Attitude Control Performance of IRVE-3

    NASA Technical Reports Server (NTRS)

    Dillman, Robert A.; Gsell, Valerie T.; Bowden, Ernest L.

    2013-01-01

    The Inflatable Reentry Vehicle Experiment 3 (IRVE-3) launched July 23, 2012, from NASA Wallops Flight Facility and successfully performed its mission, demonstrating both the survivability of a hypersonic inflatable aerodynamic decelerator in the reentry heating environment and the effect of an offset center of gravity on the aeroshell's flight L/D. The reentry vehicle separated from the launch vehicle, released and inflated its aeroshell, reoriented for atmospheric entry, and mechanically shifted its center of gravity before reaching atmospheric interface. Performance data from the entire mission was telemetered to the ground for analysis. This paper discusses the IRVE-3 mission scenario, reentry vehicle design, and as-flown performance of the attitude control system in the different phases of the mission.

  9. High temperature control rod assembly

    DOEpatents

    Vollman, Russell E.

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  10. Morphology controlled synthesis of platinum nanoparticles performed on the surface of graphene oxide using a gas-liquid interfacial reaction and its application for high-performance electrochemical sensing.

    PubMed

    Bai, Wushuang; Sheng, Qinglin; Zheng, Jianbin

    2016-07-21

    In this paper, we report a novel morphology-controlled synthetic method. Platinum (Pt) nanoparticles with three kinds of morphology (aggregation-like, cube-like and globular) were grown on the surface of graphene oxide (GO) using a simple gas-liquid interfacial reaction and Pt/GO nanocomposites were obtained successfully. According to the experimental results, the morphology of the Pt nanoparticles can be controlled by adjusting the reaction temperature with the protection of chitosan. The obtained Pt/GO nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). Then the Pt/GO nanocomposites with the three kinds of morphology were all used to fabricate electrochemical sensors. The electrochemical experimental results indicated that compared with various reported electrochemical sensors, the Pt/GO modified sensors in this work exhibit a low detection limit, high sensitivity and an extra wide linear range for the detection of nitrite. In addition, the synthesis of Pt particles based on a gas-liquid interfacial reaction provides a new platform for the controllable synthesis of nanomaterials. PMID:27181605

  11. Morphology controlled synthesis of platinum nanoparticles performed on the surface of graphene oxide using a gas-liquid interfacial reaction and its application for high-performance electrochemical sensing.

    PubMed

    Bai, Wushuang; Sheng, Qinglin; Zheng, Jianbin

    2016-07-21

    In this paper, we report a novel morphology-controlled synthetic method. Platinum (Pt) nanoparticles with three kinds of morphology (aggregation-like, cube-like and globular) were grown on the surface of graphene oxide (GO) using a simple gas-liquid interfacial reaction and Pt/GO nanocomposites were obtained successfully. According to the experimental results, the morphology of the Pt nanoparticles can be controlled by adjusting the reaction temperature with the protection of chitosan. The obtained Pt/GO nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). Then the Pt/GO nanocomposites with the three kinds of morphology were all used to fabricate electrochemical sensors. The electrochemical experimental results indicated that compared with various reported electrochemical sensors, the Pt/GO modified sensors in this work exhibit a low detection limit, high sensitivity and an extra wide linear range for the detection of nitrite. In addition, the synthesis of Pt particles based on a gas-liquid interfacial reaction provides a new platform for the controllable synthesis of nanomaterials.

  12. High-Performance Control of Two Three-Phase Permanent-Magnet Synchronous Machines in an Integrated Drive for Automotive Applications

    SciTech Connect

    Tang, Lixin; Su, Gui-Jia

    2008-01-01

    The closed-loop control of an integrated dual AC drive system is presented to control two three-phase permanent-magnet motors. A five-leg inverter is employed in the drive system; three of the inverter legs are for a main traction motor, but only two are needed for a three-phase auxiliary motor by utilizing the neutral point of the traction motor. An integrated drive with reduced component count is therefore achieved by eliminating one inverter leg and its gate drivers. A modified current control scheme based on the rotor flux orientation principle is presented. Simulation and experimental results are included to verify the independent control capability of the integrated drive.

  13. High precision high flow range control valve

    DOEpatents

    McCray, John A.

    1999-01-01

    A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90.degree. turn. In the preferred embodiment only one of the two fluid passageways contains a 90.degree. turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings.

  14. High precision high flow range control valve

    DOEpatents

    McCray, J.A.

    1999-07-13

    A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90 [degree] turn. In the preferred embodiment only one of the two fluid passageways contains a 90[degree] turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings. 12 figs.

  15. SISYPHUS: A high performance seismic inversion factory

    NASA Astrophysics Data System (ADS)

    Gokhberg, Alexey; Simutė, Saulė; Boehm, Christian; Fichtner, Andreas

    2016-04-01

    branches for the static process setup, inversion iterations, and solver runs, each branch specifying information at the event, station and channel levels. The workflow management framework is based on an embedded scripting engine that allows definition of various workflow scenarios using a high-level scripting language and provides access to all available inversion components represented as standard library functions. At present the SES3D wave propagation solver is integrated in the solution; the work is in progress for interfacing with SPECFEM3D. A separate framework is designed for interoperability with an optimization module; the workflow manager and optimization process run in parallel and cooperate by exchanging messages according to a specially designed protocol. A library of high-performance modules implementing signal pre-processing, misfit and adjoint computations according to established good practices is included. Monitoring is based on information stored in the inversion state database and at present implements a command line interface; design of a graphical user interface is in progress. The software design fits well into the common massively parallel system architecture featuring a large number of computational nodes running distributed applications under control of batch-oriented resource managers. The solution prototype has been implemented on the "Piz Daint" supercomputer provided by the Swiss Supercomputing Centre (CSCS).

  16. Strategy Guideline. Partnering for High Performance Homes

    SciTech Connect

    Prahl, Duncan

    2013-01-01

    High performance houses require a high degree of coordination and have significant interdependencies between various systems in order to perform properly, meet customer expectations, and minimize risks for the builder. Responsibility for the key performance attributes is shared across the project team and can be well coordinated through advanced partnering strategies. For high performance homes, traditional partnerships need to be matured to the next level and be expanded to all members of the project team including trades, suppliers, manufacturers, HERS raters, designers, architects, and building officials as appropriate. This guide is intended for use by all parties associated in the design and construction of high performance homes. It serves as a starting point and features initial tools and resources for teams to collaborate to continually improve the energy efficiency and durability of new houses.

  17. High performance BGMI circuit for VLWIR FPAs

    NASA Astrophysics Data System (ADS)

    Hao, Li-chao; Chen, Hong-lei; Huang, Ai-bo; Zhang, Jun-ling; Ding, Rui-jun

    2013-09-01

    An improved CMOS readout integrated circuit (ROIC) for N-on-P very long wavelength (VLWIR) detectors is designed, which has the ability to operate with a simple background suppression. It increases the integration time and the signal-to-noise ratio (SNR) of image data. A buffered gate modulation input (BGMI) cell as input circuit provides a low input resistance, high injection efficiency, and precise biasing voltage to the photodiode. By theoretically analyzing the characteristic parameters of MOS device at low temperature, a high gain's feedback amplifier is devised which using a differential stage to provide the inverting gain to improve linearity and to provide tight control of the detector bias. The final chip is fabricated with HHNEC 0.35um 1P4M process technology. The measurement results of the fabricated readout chip under 50K have successfully verified both readout function and performance improvement. With the 5.0V power supply, ROIC provides the output dynamic range over 2.5V. At the same time, the total power dissipation is less than 200mW, and the maximum readout speed is more than 2.5MHz.

  18. A low-power high-performance configurable auto-gain control loop for a digital hearing aid SoC

    NASA Astrophysics Data System (ADS)

    Chengying, Chen; Hainan, Liu; Yong, Hei; Jun, Fan; Xiaoyu, Hu

    2013-10-01

    A low-power, configurable auto-gain control loop for a digital hearing aid system on a chip (SoC) is presented. By adopting a mixed-signal feedback control structure and peak detection and judgment, it can work in automatic gain or variable gain control modes through a digital signal processing unit. A noise-reduction and dynamic range (DR) improvement technique is also used to ensure the DR of the circuit in a low-voltage supply. The circuit is implemented in an SMIC 0.13 μm 1P8M CMOS process. The measurement results show that in a 1 V power supply, 1.6 kHz input frequency and 200 mVp—p, the SFDR is 74.3 dB, the THD is 66.1 dB, and the total power is 89 μW, meeting the application requirements of hearing aid SoCs.

  19. In-flight performance optimization for rotorcraft with redundant controls

    NASA Astrophysics Data System (ADS)

    Ozdemir, Gurbuz Taha

    A conventional helicopter has limits on performance at high speeds because of the limitations of main rotor, such as compressibility issues on advancing side or stall issues on retreating side. Auxiliary lift and thrust components have been suggested to improve performance of the helicopter substantially by reducing the loading on the main rotor. Such a configuration is called the compound rotorcraft. Rotor speed can also be varied to improve helicopter performance. In addition to improved performance, compound rotorcraft and variable RPM can provide a much larger degree of control redundancy. This additional redundancy gives the opportunity to further enhance performance and handling qualities. A flight control system is designed to perform in-flight optimization of redundant control effectors on a compound rotorcraft in order to minimize power required and extend range. This "Fly to Optimal" (FTO) control law is tested in simulation using the GENHEL model. A model of the UH-60, a compound version of the UH-60A with lifting wing and vectored thrust ducted propeller (VTDP), and a generic compound version of the UH-60A with lifting wing and propeller were developed and tested in simulation. A model following dynamic inversion controller is implemented for inner loop control of roll, pitch, yaw, heave, and rotor RPM. An outer loop controller regulates airspeed and flight path during optimization. A Golden Section search method was used to find optimal rotor RPM on a conventional helicopter, where the single redundant control effector is rotor RPM. The FTO builds off of the Adaptive Performance Optimization (APO) method of Gilyard by performing low frequency sweeps on a redundant control for a fixed wing aircraft. A method based on the APO method was used to optimize trim on a compound rotorcraft with several redundant control effectors. The controller can be used to optimize rotor RPM and compound control effectors through flight test or simulations in order to

  20. Monitoring the Performance of a Neuro-Adaptive Controller

    NASA Technical Reports Server (NTRS)

    Schumann, Johann; Gupta, Pramod

    2004-01-01

    Traditional control has proven to be ineffective to deal with catastrophic changes or slow degradation of complex, highly nonlinear systems like aircraft or spacecraft, robotics, or flexible manufacturing systems. Control systems which can adapt toward changes in the plant have been proposed as they offer many advantages (e.g., better performance, controllability of aircraft despite of a damaged wing). In the last few years, use of neural networks in adaptive controllers (neuro-adaptive control) has been studied actively. Neural networks of various architectures have been used successfully for online learning adaptive controllers. In such a typical control architecture, the neural network receives as an input the current deviation between desired and actual plant behavior and, by on-line training, tries to minimize this discrepancy (e.g.; by producing a control augmentation signal). Even though neuro-adaptive controllers offer many advantages, they have not been used in mission- or safety-critical applications, because performance and safety guarantees cannot b e provided at development time-a major prerequisite for safety certification (e.g., by the FAA or NASA). Verification and Validation (V&V) of an adaptive controller requires the development of new analysis techniques which can demonstrate that the control system behaves safely under all operating conditions. Because of the requirement to adapt toward unforeseen changes during operation, i.e., in real time, design-time V&V is not sufficient.

  1. Dinosaurs can fly -- High performance refining

    SciTech Connect

    Treat, J.E.

    1995-09-01

    High performance refining requires that one develop a winning strategy based on a clear understanding of one`s position in one`s company`s value chain; one`s competitive position in the products markets one serves; and the most likely drivers and direction of future market forces. The author discussed all three points, then described measuring performance of the company. To become a true high performance refiner often involves redesigning the organization as well as the business processes. The author discusses such redesigning. The paper summarizes ten rules to follow to achieve high performance: listen to the market; optimize; organize around asset or area teams; trust the operators; stay flexible; source strategically; all maintenance is not equal; energy is not free; build project discipline; and measure and reward performance. The paper then discusses the constraints to the implementation of change.

  2. High spin rate magnetic controller for nanosatellites

    NASA Astrophysics Data System (ADS)

    Slavinskis, A.; Kvell, U.; Kulu, E.; Sünter, I.; Kuuste, H.; Lätt, S.; Voormansik, K.; Noorma, M.

    2014-02-01

    This paper presents a study of a high rate closed-loop spin controller that uses only electromagnetic coils as actuators. The controller is able to perform spin rate control and simultaneously align the spin axis with the Earth's inertial reference frame. It is implemented, optimised and simulated for a 1-unit CubeSat ESTCube-1 to fulfil its mission requirements: spin the satellite up to 360 deg s-1 around the z-axis and align its spin axis with the Earth's polar axis with a pointing error of less than 3°. The attitude of the satellite is determined using a magnetic field vector, a Sun vector and angular velocity. It is estimated using an Unscented Kalman Filter and controlled using three electromagnetic coils. The algorithm is tested in a simulation environment that includes models of space environment and environmental disturbances, sensor and actuator emulation, attitude estimation, and a model to simulate the time delay caused by on-board calculations. In addition to the normal operation mode, analyses of reduced satellite functionality are performed: significant errors of attitude estimation due to non-operational Sun sensors; and limited actuator functionality due to two non-operational coils. A hardware-in-the-loop test is also performed to verify on-board software.

  3. System analysis of high performance MHD systems

    SciTech Connect

    Chang, S.L.; Berry, G.F.; Hu, N.

    1988-01-01

    This paper presents the results of an investigation on the upper ranges of performance that an MHD power plant using advanced technology assumptions might achieve and a parametric study on the key variables affecting this high performance. To simulate a high performance MHD power plant and conduct a parametric study, the Systems Analysis Language Translator (SALT) code developed at Argonne National Laboratory was used. The parametric study results indicate that the overall efficiency of an MHD power plant can be further increased subject to the improvement of some key variables such as, the MHD generator inverter efficiency, channel electrical loading factor, magnetic field strength, preheated air temperature, and combustor heat loss. In an optimization calculation, the simulated high performance MHD power plant using advanced technology assumptions can attain an ultra high overall efficiency, exceeding 62%. 12 refs., 5 figs., 4 tabs.

  4. High performance pitch-based carbon fiber

    SciTech Connect

    Tadokoro, Hiroyuki; Tsuji, Nobuyuki; Shibata, Hirotaka; Furuyama, Masatoshi

    1996-12-31

    The high performance pitch-based carbon fiber with smaller diameter, six micro in developed by Nippon Graphite Fiber Corporation. This fiber possesses high tensile modulus, high tensile strength, excellent yarn handle ability, low thermal expansion coefficient, and high thermal conductivity which make it an ideal material for space applications such as artificial satellites. Performance of this fiber as a reinforcement of composites was sufficient. With these characteristics, this pitch-based carbon fiber is expected to find wide variety of possible applications in space structures, industrial field, sporting goods and civil infrastructures.

  5. Highlighting High Performance: Whitman Hanson Regional High School; Whitman, Massachusetts

    SciTech Connect

    Not Available

    2006-06-01

    This brochure describes the key high-performance building features of the Whitman-Hanson Regional High School. The brochure was paid for by the Massachusetts Technology Collaborative as part of their Green Schools Initiative. High-performance features described are daylighting and energy-efficient lighting, indoor air quality, solar and wind energy, building envelope, heating and cooling systems, water conservation, and acoustics. Energy cost savings are also discussed.

  6. Microwave performance of an optically controlled AlGaAs/GaAs high electron mobility transistor and GaAs MESFET

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Bhasin, Kul. B.

    Direct current and also the microwave characteristics of optically illuminated AlGaAs/GaAs HEMT are experimentally measured for the first time and compared with that of GaAs MESFET. The results showed that the average increase in the gain is 2.89 dB under 1.7 nW/sq cm optical intensity at 0.83 microns. Further, the effect of illumination on S-parameters is more pronounced when the devices are biased close to pinch off. Novel applications of optically illuminated HEMT as a variable gain amplifier, high speed high frequency photo detector, and mixer are demonstrated.

  7. Microwave performance of an optically controlled AlGaAs/GaAs high electron mobility transistor and GaAs MESFET

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.

    1987-12-01

    Direct current and also the microwave characteristics of optically illuminated AlGaAs/GaAs HEMT are experimentally measured for the first time and compared with that of GaAs MESFET. The results showed that the average increase in the gain is 2.89 dB under 1.7 mW optical intensity at 0.83 microns. Further, the effect of illumination on S-parameters is more pronounced when the devices are biased close to pinch off. Novel applications of optically illuminated HEMT as a variable gain amplifier, high speed high frequency photodetector, and mixer are demonstrated.

  8. Neurocognitive control in dance perception and performance.

    PubMed

    Bläsing, Bettina; Calvo-Merino, Beatriz; Cross, Emily S; Jola, Corinne; Honisch, Juliane; Stevens, Catherine J

    2012-02-01

    Dance is a rich source of material for researchers interested in the integration of movement and cognition. The multiple aspects of embodied cognition involved in performing and perceiving dance have inspired scientists to use dance as a means for studying motor control, expertise, and action-perception links. The aim of this review is to present basic research on cognitive and neural processes implicated in the execution, expression, and observation of dance, and to bring into relief contemporary issues and open research questions. The review addresses six topics: 1) dancers' exemplary motor control, in terms of postural control, equilibrium maintenance, and stabilization; 2) how dancers' timing and on-line synchronization are influenced by attention demands and motor experience; 3) the critical roles played by sequence learning and memory; 4) how dancers make strategic use of visual and motor imagery; 5) the insights into the neural coupling between action and perception yielded through exploration of the brain architecture mediating dance observation; and 6) a neuroesthetics perspective that sheds new light on the way audiences perceive and evaluate dance expression. Current and emerging issues are presented regarding future directions that will facilitate the ongoing dialog between science and dance.

  9. Untargeted metabolomics in doping control: detection of new markers of testosterone misuse by ultrahigh performance liquid chromatography coupled to high-resolution mass spectrometry.

    PubMed

    Raro, Montse; Ibáñez, María; Gil, Rubén; Fabregat, Andreu; Tudela, Eva; Deventer, Koen; Ventura, Rosa; Segura, Jordi; Marcos, Josep; Kotronoulas, Aristotelis; Joglar, Jesús; Farré, Magi; Yang, Sheng; Xing, Yanyi; Van Eenoo, Peter; Pitarch, Elena; Hernández, Félix; Sancho, Juan Vicente; Pozo, Óscar J

    2015-08-18

    The use of untargeted metabolomics for the discovery of markers is a promising and virtually unexplored tool in the doping control field. Hybrid quadrupole time-of-flight (QTOF) and hybrid quadrupole Orbitrap (Q Exactive) mass spectrometers, coupled to ultrahigh pressure liquid chromatography, are excellent tools for this purpose. In the present work, QTOF and Q Exactive have been used to look for markers for testosterone cypionate misuse by means of untargeted metabolomics. Two different groups of urine samples were analyzed, collected before and after the intramuscular administration of testosterone cypionate. In order to avoid analyte losses in the sample treatment, samples were just 2-fold diluted with water and directly injected into the chromatographic system. Samples were analyzed in both positive and negative ionization modes. Data from both systems were treated under untargeted metabolomic strategies using XCMS application and multivariate analysis. Results from the two mass spectrometers differed in the number of detected features, but both led to the same potential marker for the particular testosterone ester misuse. The in-depth study of the MS and MS/MS behavior of this marker allowed for the establishment of 1-cyclopentenoylglycine as a feasible structure. The putative structure was confirmed by comparison with synthesized material. This potential marker seems to come from the metabolism of the cypionic acid release after hydrolysis of the administered ester. Its suitability for doping control has been evaluated.

  10. Overview of high performance aircraft propulsion research

    NASA Technical Reports Server (NTRS)

    Biesiadny, Thomas J.

    1992-01-01

    The overall scope of the NASA Lewis High Performance Aircraft Propulsion Research Program is presented. High performance fighter aircraft of interest include supersonic flights with such capabilities as short take off and vertical landing (STOVL) and/or high maneuverability. The NASA Lewis effort involving STOVL propulsion systems is focused primarily on component-level experimental and analytical research. The high-maneuverability portion of this effort, called the High Alpha Technology Program (HATP), is part of a cooperative program among NASA's Lewis, Langley, Ames, and Dryden facilities. The overall objective of the NASA Inlet Experiments portion of the HATP, which NASA Lewis leads, is to develop and enhance inlet technology that will ensure high performance and stability of the propulsion system during aircraft maneuvers at high angles of attack. To accomplish this objective, both wind-tunnel and flight experiments are used to obtain steady-state and dynamic data, and computational fluid dynamics (CFD) codes are used for analyses. This overview of the High Performance Aircraft Propulsion Research Program includes a sampling of the results obtained thus far and plans for the future.

  11. High Performance Work Systems for Online Education

    ERIC Educational Resources Information Center

    Contacos-Sawyer, Jonna; Revels, Mark; Ciampa, Mark

    2010-01-01

    The purpose of this paper is to identify the key elements of a High Performance Work System (HPWS) and explore the possibility of implementation in an online institution of higher learning. With the projected rapid growth of the demand for online education and its importance in post-secondary education, providing high quality curriculum, excellent…

  12. NCI's Transdisciplinary High Performance Scientific Data Platform

    NASA Astrophysics Data System (ADS)

    Evans, Ben; Antony, Joseph; Bastrakova, Irina; Car, Nicholas; Cox, Simon; Druken, Kelsey; Evans, Bradley; Fraser, Ryan; Ip, Alex; Kemp, Carina; King, Edward; Minchin, Stuart; Larraondo, Pablo; Pugh, Tim; Richards, Clare; Santana, Fabiana; Smillie, Jon; Trenham, Claire; Wang, Jingbo; Wyborn, Lesley

    2016-04-01

    The Australian National Computational Infrastructure (NCI) manages Earth Systems data collections sourced from several domains and organisations onto a single High Performance Data (HPD) Node to further Australia's national priority research and innovation agenda. The NCI HPD Node has rapidly established its value, currently managing over 10 PBytes of datasets from collections that span a wide range of disciplines including climate, weather, environment, geoscience, geophysics, water resources and social sciences. Importantly, in order to facilitate broad user uptake, maximise reuse and enable transdisciplinary access through software and standardised interfaces, the datasets, associated information systems and processes have been incorporated into the design and operation of a unified platform that NCI has called, the National Environmental Research Data Interoperability Platform (NERDIP). The key goal of the NERDIP is to regularise data access so that it is easily discoverable, interoperable for different domains and enabled for high performance methods. It adopts and implements international standards and data conventions, and promotes scientific integrity within a high performance computing and data analysis environment. NCI has established a rich and flexible computing environment to access to this data, through the NCI supercomputer; a private cloud that supports both domain focused virtual laboratories and in-common interactive analysis interfaces; as well as remotely through scalable data services. Data collections of this importance must be managed with careful consideration of both their current use and the needs of the end-communities, as well as its future potential use, such as transitioning to more advanced software and improved methods. It is therefore critical that the data platform is both well-managed and trusted for stable production use (including transparency and reproducibility), agile enough to incorporate new technological advances and

  13. COLLABORATIVE APPROACH IN THE DEVELOPMENT OF HIGH PERFORMANCE BRAIN-COMPUTER INTERFACES FOR A NEUROPROSTHETIC ARM: TRANSLATION FROM ANIMAL MODELS TO HUMAN CONTROL

    PubMed Central

    Collinger, Jennifer; Kryger, Michael; Barbara, Richard; Betler, Timothy; Bowsher, Kristen; Brown, Elke HP; Clanton, Samuel T.; Degenhart, Alan; Foldes, Stephen; Gaunt, Robert A; Gyulai, Ferenc E; Harchick, Elizabeth A; Harrington, Deborah; Helder, John B; Hemmes, Timothy; Johannes, Matthew S; Katyal, Kapil D; Ling, Geoffrey SF; McMorland, Angus JC; Palko, Karina; Para, Matthew P; Scheuermann, Janet; Schwartz, Andrew; Skidmore, Elizabeth R; Solzbacher, Florian; Srikameswaran, Anita V.; Swanson, Dennis P; Swetz, Scott; Tyler-Kabara, Elizabeth C; Velliste, Meel; Wang, Wei; Weber, Douglas J; Wodlinger, Brian; Boninger, Michael

    2013-01-01

    Our research group recently demonstrated that a person with tetraplegia could use a brain-computer interface (BCI) to control a sophisticated anthropomorphic robotic arm with skill and speed approaching that of an able-bodied person. This multi-year study exemplifies important principles in translating research from foundational theory and animal experiments into a clinical study. We present a roadmap that may serve as an example for other areas of clinical device research as well as an update on study results. Prior to conducting a multi-year clinical trial, years of animal research preceded BCI testing in an epilepsy monitoring unit, and then in a short term (28 days) clinical investigation. Scientists and engineers developed the necessary robotic and surgical hardware, software environment, data analysis techniques, and training paradigms. Coordination among researchers, funding institutes and regulatory bodies ensured that the study would provide valuable scientific information in a safe environment for the study participant. Finally, clinicians from neurosurgery, anesthesiology, physiatry, psychology and occupational therapy all worked in a multidisciplinary team along with the other researchers to conduct a multi-year BCI clinical study. This teamwork and coordination can be used as a model for others attempting to translate basic science into real-world clinical situations. PMID:24528900

  14. Collaborative approach in the development of high-performance brain-computer interfaces for a neuroprosthetic arm: translation from animal models to human control.

    PubMed

    Collinger, Jennifer L; Kryger, Michael A; Barbara, Richard; Betler, Timothy; Bowsher, Kristen; Brown, Elke H P; Clanton, Samuel T; Degenhart, Alan D; Foldes, Stephen T; Gaunt, Robert A; Gyulai, Ferenc E; Harchick, Elizabeth A; Harrington, Deborah; Helder, John B; Hemmes, Timothy; Johannes, Matthew S; Katyal, Kapil D; Ling, Geoffrey S F; McMorland, Angus J C; Palko, Karina; Para, Matthew P; Scheuermann, Janet; Schwartz, Andrew B; Skidmore, Elizabeth R; Solzbacher, Florian; Srikameswaran, Anita V; Swanson, Dennis P; Swetz, Scott; Tyler-Kabara, Elizabeth C; Velliste, Meel; Wang, Wei; Weber, Douglas J; Wodlinger, Brian; Boninger, Michael L

    2014-02-01

    Our research group recently demonstrated that a person with tetraplegia could use a brain-computer interface (BCI) to control a sophisticated anthropomorphic robotic arm with skill and speed approaching that of an able-bodied person. This multiyear study exemplifies important principles in translating research from foundational theory and animal experiments into a clinical study. We present a roadmap that may serve as an example for other areas of clinical device research as well as an update on study results. Prior to conducting a multiyear clinical trial, years of animal research preceded BCI testing in an epilepsy monitoring unit, and then in a short-term (28 days) clinical investigation. Scientists and engineers developed the necessary robotic and surgical hardware, software environment, data analysis techniques, and training paradigms. Coordination among researchers, funding institutes, and regulatory bodies ensured that the study would provide valuable scientific information in a safe environment for the study participant. Finally, clinicians from neurosurgery, anesthesiology, physiatry, psychology, and occupational therapy all worked in a multidisciplinary team along with the other researchers to conduct a multiyear BCI clinical study. This teamwork and coordination can be used as a model for others attempting to translate basic science into real-world clinical situations.

  15. Multi-wavelength high-performance liquid chromatographic fingerprints and chemometrics to predict the antioxidant activity of Turnera diffusa as part of its quality control.

    PubMed

    Lucio-Gutiérrez, J Ricardo; Garza-Juárez, Aurora; Coello, J; Maspoch, S; Salazar-Cavazos, M L; Salazar-Aranda, Ricardo; Waksman de Torres, Noemi

    2012-04-27

    The determination of the antioxidant activity of Turnera diffusa using partial least squares regression (PLSR) on chromatographic data is presented. The chromatograms were recorded with a diode array detector and, for each sample, an enhanced fingerprint was constructed by compiling into a single data vector the chromatograms at four wavelengths (216, 238, 254 and 345 nm). The wavelengths were selected from a contour plot, in order to obtain the greater number of peaks at each of the wavelengths. A further pretreatment of the data that included baseline correction, scaling and correlation optimized warping was performed. Optimal values of the parameters used in the warping were found by means of simplex optimization. A PLSR model with four latent variables (LV) explained 52.5% of X variance and 98.4% of Y, with a root mean square error for cross validation of 6.02. To evaluate its reliability, it was applied to an external prediction set, retrieving a relative standard error for prediction of 7.8%. The study of the most important variables for the regression indicated the chromatographic peaks related to antioxidant activity at the used wavelengths. PMID:22405537

  16. Development characterization and use of a high-performance enzymatic time-temperature integrator for the control of sterilization process' impacts.

    PubMed

    Guiavarc'h, Yann; Van Loey, Ann; Zuber, François; Hendrickx, Marc

    2004-10-01

    A small sized single-component enzymatic time temperature integrator (TTI) was developed. It consisted of glass beads coated with Bacillus licheniformis alpha-amylase (BLA) and stabilizing additives in a dehydrated form. Post heating residual enzymatic activity was used as a response property of the TTI. Under isothermal conditions, different batches of the system were characterized by z(TTI)-values around 13.5 degrees C in the temperature range 100-130 degrees C as well as by their ability to provide a response within 5 min after thermal processing. When used under non-isothermal conditions in a model food (silicone spheres), the system allowed to measure process-values (zTTI)F(121.1 degrees C) up to 60 min with an average error of 10.9%. The capabilities of the system were validated in a real solid/liquid food matrix sterilized by retorting. The combination of F(TTI)-values with heat transfer simulations based on finite difference calculations allowed for the determination of process values, which evaluated actual process-values (10 degrees C)F(121.1 degrees C) up to 90 min with an average error of 11.4%. The good performances of the system as well as its easiness of preparation and use, make the latter a valuable biological device for thermal process assessment.

  17. Programming high-performance reconfigurable computers

    NASA Astrophysics Data System (ADS)

    Smith, Melissa C.; Peterson, Gregory D.

    2001-07-01

    High Performance Computers (HPC) provide dramatically improved capabilities for a number of defense and commercial applications, but often are too expensive to acquire and to program. The smaller market and customized nature of HPC architectures combine to increase the cost of most such platforms. To address the problems with high hardware costs, one may create more inexpensive Beowolf clusters of dedicated commodity processors. Despite the benefit of reduced hardware costs, programming the HPC platforms to achieve high performance often proves extremely time-consuming and expensive in practice. In recent years, programming productivity gains come from the development of common APIs and libraries of functions to support distributed applications. Examples include PVM, MPI, BLAS, and VSIPL. The implementation of each API or library is optimized for a given platform, but application developers can write code that is portable across specific HPC architectures. The application of reconfigurable computing (RC) into HPC platforms promises significantly enhanced performance and flexibility at a modest cost. Unfortunately, configuring (programming) the reconfigurable computing nodes remains a challenging task and relatively little work to date has focused on potential high performance reconfigurable computing (HPRC) platforms consisting of reconfigurable nodes paired with processing nodes. This paper addresses the challenge of effectively exploiting HPRC resources by first considering the performance evaluation and optimization problem before turning to improving the programming infrastructure used for porting applications to HPRC platforms.

  18. Performance variability of highly parallel architectures

    SciTech Connect

    Kramer, William T.C.; Ryan, Clint

    2003-05-01

    The design and evaluation of high performance computers has concentrated on increasing computational speed for applications. This performance is often measured on a well configured dedicated system to show the best case. In the real environment, resources are not always dedicated to a single task, and systems run tasks that may influence each other, so run times vary, sometimes to an unreasonably large extent. This paper explores the amount of variation seen across four large distributed memory systems in a systematic manner. It then analyzes the causes for the variations seen and discusses what can be done to decrease the variation without impacting performance.

  19. Achieving High Performance Perovskite Solar Cells

    NASA Astrophysics Data System (ADS)

    Yang, Yang

    2015-03-01

    Recently, metal halide perovskite based solar cell with the characteristics of rather low raw materials cost, great potential for simple process and scalable production, and extreme high power conversion efficiency (PCE), have been highlighted as one of the most competitive technologies for next generation thin film photovoltaic (PV). In UCLA, we have realized an efficient pathway to achieve high performance pervoskite solar cells, where the findings are beneficial to this unique materials/devices system. Our recent progress lies in perovskite film formation, defect passivation, transport materials design, interface engineering with respect to high performance solar cell, as well as the exploration of its applications beyond photovoltaics. These achievements include: 1) development of vapor assisted solution process (VASP) and moisture assisted solution process, which produces perovskite film with improved conformity, high crystallinity, reduced recombination rate, and the resulting high performance; 2) examination of the defects property of perovskite materials, and demonstration of a self-induced passivation approach to reduce carrier recombination; 3) interface engineering based on design of the carrier transport materials and the electrodes, in combination with high quality perovskite film, which delivers 15 ~ 20% PCEs; 4) a novel integration of bulk heterojunction to perovskite solar cell to achieve better light harvest; 5) fabrication of inverted solar cell device with high efficiency and flexibility and 6) exploration the application of perovskite materials to photodetector. Further development in film, device architecture, and interfaces will lead to continuous improved perovskite solar cells and other organic-inorganic hybrid optoelectronics.

  20. Performance analysis of memory hierachies in high performance systems

    SciTech Connect

    Yogesh, A.

    1993-07-01

    This thesis studies memory bandwidth as a performance predictor of programs. The focus of this work is on computationally intensive programs. These programs are the most likely to access large amounts of data, stressing the memory system. Computationally intensive programs are also likely to use highly optimizing compilers to produce the fastest executables possible. Methods to reduce the amount of data traffic by increasing the average number of references to each item while it resides in the cache are explored. Increasing the average number of references to each cache item reduces the number of memory requests. Chapter 2 describes the DLX architecture. This is the architecture on which all the experiments were performed. Chapter 3 studies memory moves as a performance predictor for a group of application programs. Chapter 4 introduces a model to study the performance of programs in the presence of memory hierarchies. Chapter 5 explores some compiler optimizations that can help increase the references to each item while it resides in the cache.

  1. High performance APCS conceptual design and evaluation scoping study

    SciTech Connect

    Soelberg, N.; Liekhus, K.; Chambers, A.; Anderson, G.

    1998-02-01

    This Air Pollution Control System (APCS) Conceptual Design and Evaluation study was conducted to evaluate a high-performance (APC) system for minimizing air emissions from mixed waste thermal treatment systems. Seven variations of high-performance APCS designs were conceptualized using several design objectives. One of the system designs was selected for detailed process simulation using ASPEN PLUS to determine material and energy balances and evaluate performance. Installed system capital costs were also estimated. Sensitivity studies were conducted to evaluate the incremental cost and benefit of added carbon adsorber beds for mercury control, specific catalytic reduction for NO{sub x} control, and offgas retention tanks for holding the offgas until sample analysis is conducted to verify that the offgas meets emission limits. Results show that the high-performance dry-wet APCS can easily meet all expected emission limits except for possibly mercury. The capability to achieve high levels of mercury control (potentially necessary for thermally treating some DOE mixed streams) could not be validated using current performance data for mercury control technologies. The engineering approach and ASPEN PLUS modeling tool developed and used in this study identified APC equipment and system performance, size, cost, and other issues that are not yet resolved. These issues need to be addressed in feasibility studies and conceptual designs for new facilities or for determining how to modify existing facilities to meet expected emission limits. The ASPEN PLUS process simulation with current and refined input assumptions and calculations can be used to provide system performance information for decision-making, identifying best options, estimating costs, reducing the potential for emission violations, providing information needed for waste flow analysis, incorporating new APCS technologies in existing designs, or performing facility design and permitting activities.

  2. Improved precision and accuracy for high-performance liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometric exact mass measurement of small molecules from the simultaneous and controlled introduction of internal calibrants via a second electrospray nebuliser.

    PubMed

    Herniman, Julie M; Bristow, Tony W T; O'Connor, Gavin; Jarvis, Jackie; Langley, G John

    2004-01-01

    The use of a second electrospray nebuliser has proved to be highly successful for exact mass measurement during high-performance liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry (HPLC/FTICRMS). Much improved accuracy and precision of mass measurement were afforded by the introduction of the internal calibration solution, thus overcoming space charge issues due to the lack of control over relative ion abundances of the species eluting from the HPLC column. Further, issues of suppression of ionisation, observed when using a T-piece method, are addressed and this simple system has significant benefits over other more elaborate approaches providing data that compares very favourably with these other approaches. The technique is robust, flexible and transferable and can be used in conjunction with HPLC, infusion or flow injection analysis (FIA) to provide constant internal calibration signals to allow routine, accurate and precise mass measurements to be recorded.

  3. An Introduction to Controller Performance Assessment in Process Control Class through Stiction in Control Valves

    ERIC Educational Resources Information Center

    Srinivasan, Ranganathan; Rengaswamy, Raghunathan; Harris, Sandra

    2007-01-01

    In this paper, we discuss a simple liquid level experiment that can be used to teach nonlinear phenomena in process control through stiction in control valves. This experiment can be used to introduce the undergraduate students to the area of Controller Performance Assessment (CPA). The experiment is very easy to set-up and demonstrate. While…

  4. 1997 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G. (Editor)

    1999-01-01

    The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Aerodynamic Performance Workshop on February 25-28, 1997. The workshop was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of Configuration Aerodynamics (transonic and supersonic cruise drag, prediction and minimization), High-Lift, Flight Controls, Supersonic Laminar Flow Control, and Sonic Boom Prediction. The workshop objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientist and engineers working HSCT aerodynamics. In particular, single- and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT Motion Simulator results were presented along with executives summaries for all the Aerodynamic Performance technology areas.

  5. Strategy Guideline: Partnering for High Performance Homes

    SciTech Connect

    Prahl, D.

    2013-01-01

    High performance houses require a high degree of coordination and have significant interdependencies between various systems in order to perform properly, meet customer expectations, and minimize risks for the builder. Responsibility for the key performance attributes is shared across the project team and can be well coordinated through advanced partnering strategies. For high performance homes, traditional partnerships need to be matured to the next level and be expanded to all members of the project team including trades, suppliers, manufacturers, HERS raters, designers, architects, and building officials as appropriate. In an environment where the builder is the only source of communication between trades and consultants and where relationships are, in general, adversarial as opposed to cooperative, the chances of any one building system to fail are greater. Furthermore, it is much harder for the builder to identify and capitalize on synergistic opportunities. Partnering can help bridge the cross-functional aspects of the systems approach and achieve performance-based criteria. Critical success factors for partnering include support from top management, mutual trust, effective and open communication, effective coordination around common goals, team building, appropriate use of an outside facilitator, a partnering charter progress toward common goals, an effective problem-solving process, long-term commitment, continuous improvement, and a positive experience for all involved.

  6. High performance stationary phases for planar chromatography.

    PubMed

    Poole, Salwa K; Poole, Colin F

    2011-05-13

    The kinetic performance of stabilized particle layers, particle membranes, and thin films for thin-layer chromatography is reviewed with a focus on how layer characteristics and experimental conditions affect the observed plate height. Forced flow and pressurized planar electrochromatography are identified as the best candidates to overcome the limited performance achieved by capillary flow for stabilized particle layers. For conventional and high performance plates band broadening is dominated by molecular diffusion at low mobile phase velocities typical of capillary flow systems and by mass transfer with a significant contribution from flow anisotropy at higher flow rates typical of forced flow systems. There are few possible changes to the structure of stabilized particle layers that would significantly improve their performance for capillary flow systems while for forced flow a number of avenues for further study are identified. New media for ultra thin-layer chromatography shows encouraging possibilities for miniaturized high performance systems but the realization of their true performance requires improvements in instrumentation for sample application and detection.

  7. Using LEADS to shift to high performance.

    PubMed

    Fenwick, Shauna; Hagge, Erna

    2016-03-01

    Health systems across Canada are tasked to measure results of all their strategic initiatives. Included in most strategic plans is leadership development. How to measure leadership effectiveness in relation to organizational objectives is key in determining organizational effectiveness. The following findings offer considerations for a 21(st)-century approach to shifting to high-performance systems.

  8. Project materials [Commercial High Performance Buildings Project

    SciTech Connect

    2001-01-01

    The Consortium for High Performance Buildings (ChiPB) is an outgrowth of DOE'S Commercial Whole Buildings Roadmapping initiatives. It is a team-driven public/private partnership that seeks to enable and demonstrate the benefit of buildings that are designed, built and operated to be energy efficient, environmentally sustainable, superior quality, and cost effective.

  9. High Performance Builder Spotlight: Imagine Homes

    SciTech Connect

    2011-01-01

    Imagine Homes, working with the DOE's Building America research team member IBACOS, has developed a system that can be replicated by other contractors to build affordable, high-performance homes. Imagine Homes has used the system to produce more than 70 Builders Challenge-certified homes per year in San Antonio over the past five years.

  10. Commercial Buildings High Performance Rooftop Unit Challenge

    SciTech Connect

    2011-12-16

    The U.S. Department of Energy (DOE) and the Commercial Building Energy Alliances (CBEAs) are releasing a new design specification for high performance rooftop air conditioning units (RTUs). Manufacturers who develop RTUs based on this new specification will find strong interest from the commercial sector due to the energy and financial savings.

  11. Debugging a high performance computing program

    DOEpatents

    Gooding, Thomas M.

    2013-08-20

    Methods, apparatus, and computer program products are disclosed for debugging a high performance computing program by gathering lists of addresses of calling instructions for a plurality of threads of execution of the program, assigning the threads to groups in dependence upon the addresses, and displaying the groups to identify defective threads.

  12. Debugging a high performance computing program

    DOEpatents

    Gooding, Thomas M.

    2014-08-19

    Methods, apparatus, and computer program products are disclosed for debugging a high performance computing program by gathering lists of addresses of calling instructions for a plurality of threads of execution of the program, assigning the threads to groups in dependence upon the addresses, and displaying the groups to identify defective threads.

  13. Co-design for High Performance Computing

    NASA Astrophysics Data System (ADS)

    Rodrigues, Arun; Dosanjh, Sudip; Hemmert, Scott

    2010-09-01

    Co-design has been identified as a key strategy for achieving Exascale computing in this decade. This paper describes the need for co-design in High Performance Computing related research in embedded computing the development of hardware/software co-simulation methods.

  14. High Performance Work Organizations. Myths and Realities.

    ERIC Educational Resources Information Center

    Kerka, Sandra

    Organizations are being urged to become "high performance work organizations" (HPWOs) and vocational teachers have begun considering how best to prepare workers for them. Little consensus exists as to what HPWOs are. Several common characteristics of HPWOs have been identified, and two distinct models of HPWOs are emerging in the United States.…

  15. High-Performance, Low Environmental Impact Refrigerants

    NASA Technical Reports Server (NTRS)

    McCullough, E. T.; Dhooge, P. M.; Glass, S. M.; Nimitz, J. S.

    2001-01-01

    Refrigerants used in process and facilities systems in the US include R-12, R-22, R-123, R-134a, R-404A, R-410A, R-500, and R-502. All but R-134a, R-404A, and R-410A contain ozone-depleting substances that will be phased out under the Montreal Protocol. Some of the substitutes do not perform as well as the refrigerants they are replacing, require new equipment, and have relatively high global warming potentials (GWPs). New refrigerants are needed that addresses environmental, safety, and performance issues simultaneously. In efforts sponsored by Ikon Corporation, NASA Kennedy Space Center (KSC), and the US Environmental Protection Agency (EPA), ETEC has developed and tested a new class of refrigerants, the Ikon (registered) refrigerants, based on iodofluorocarbons (IFCs). These refrigerants are nonflammable, have essentially zero ozone-depletion potential (ODP), low GWP, high performance (energy efficiency and capacity), and can be dropped into much existing equipment.

  16. High performance flight simulation at NASA Langley

    NASA Technical Reports Server (NTRS)

    Cleveland, Jeff I., II; Sudik, Steven J.; Grove, Randall D.

    1992-01-01

    The use of real-time simulation at the NASA facility is reviewed specifically with regard to hardware, software, and the use of a fiberoptic-based digital simulation network. The network hardware includes supercomputers that support 32- and 64-bit scalar, vector, and parallel processing technologies. The software include drivers, real-time supervisors, and routines for site-configuration management and scheduling. Performance specifications include: (1) benchmark solution at 165 sec for a single CPU; (2) a transfer rate of 24 million bits/s; and (3) time-critical system responsiveness of less than 35 msec. Simulation applications include the Differential Maneuvering Simulator, Transport Systems Research Vehicle simulations, and the Visual Motion Simulator. NASA is shown to be in the final stages of developing a high-performance computing system for the real-time simulation of complex high-performance aircraft.

  17. Cost and performance of activated carbon injection for mercury control

    SciTech Connect

    2006-08-15

    Activated carbon injection (ACI) is one technology being developed to absorb mercury from mercury emitted from coal-fired power plants. In 2003/04, the USDOE and NETL selected 14 projects to test and evaluate mercury control technologies. While field testing is still ongoing, DOE/NETL recently completed an economic analysis of mercury control for six test sites spanning three ACI variations - conventional powdered activated carbon (PAC), brominated PAC and conventional PAC combined with a sorbent enhancement additive (SEA) applied to the coal. To evaluate the progress of the field testing program and discern the performance of ACI, a data adjustment methodology was developed to account for baseline methane capture. This data were used to perform economic analyses to achieve low, mid and high levels of mercury control. The costs are given in the article. Full details are available on the DOE/NETL website, www.netl.doe.gov. 2 figs., 1 photo.

  18. Strategy Guideline. High Performance Residential Lighting

    SciTech Connect

    Holton, J.

    2012-02-01

    This report has been developed to provide a tool for the understanding and application of high performance lighting in the home. The strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner’s expectations for high quality lighting.

  19. High Performance Woven Mesh Heat Exchangers

    NASA Astrophysics Data System (ADS)

    Wirtz, Richard A.; Li, Chen; Park, Ji-Wook; Xu, Jun

    2002-07-01

    Simple-to-fabricate woven mesh structures, consisting of bonded laminates of two-dimensional plain-weave conductive screens, or three-dimensional orthogonal weaves are described. Geometric equations show that these porous matrices can be fabricated to have a wide range of porosity and a highly anisotropic thermal conductivity vector. A mathematical model of the thermal performance of such a mesh, deployed as a heat exchange surface, is developed. Measurements of pressure drop and overall heat transfer rate are reported and used with the performance model to develop correlation equations of mesh friction factor and Colburn j-factor as a function of coolant properties, mesh characteristics and flow rate through the mesh. A heat exchanger performance analysis delineates conditions where the two mesh technologies offer superior performance.

  20. High-performance commercial building systems

    SciTech Connect

    Selkowitz, Stephen

    2003-10-01

    This report summarizes key technical accomplishments resulting from the three year PIER-funded R&D program, ''High Performance Commercial Building Systems'' (HPCBS). The program targets the commercial building sector in California, an end-use sector that accounts for about one-third of all California electricity consumption and an even larger fraction of peak demand, at a cost of over $10B/year. Commercial buildings also have a major impact on occupant health, comfort and productivity. Building design and operations practices that influence energy use are deeply engrained in a fragmented, risk-averse industry that is slow to change. Although California's aggressive standards efforts have resulted in new buildings designed to use less energy than those constructed 20 years ago, the actual savings realized are still well below technical and economic potentials. The broad goal of this program is to develop and deploy a set of energy-saving technologies, strategies, and techniques, and improve processes for designing, commissioning, and operating commercial buildings, while improving health, comfort, and performance of occupants, all in a manner consistent with sound economic investment practices. Results are to be broadly applicable to the commercial sector for different building sizes and types, e.g. offices and schools, for different classes of ownership, both public and private, and for owner-occupied as well as speculative buildings. The program aims to facilitate significant electricity use savings in the California commercial sector by 2015, while assuring that these savings are affordable and promote high quality indoor environments. The five linked technical program elements contain 14 projects with 41 distinct R&D tasks. Collectively they form a comprehensive Research, Development, and Demonstration (RD&D) program with the potential to capture large savings in the commercial building sector, providing significant economic benefits to building owners and

  1. A Linux Workstation for High Performance Graphics

    NASA Technical Reports Server (NTRS)

    Geist, Robert; Westall, James

    2000-01-01

    The primary goal of this effort was to provide a low-cost method of obtaining high-performance 3-D graphics using an industry standard library (OpenGL) on PC class computers. Previously, users interested in doing substantial visualization or graphical manipulation were constrained to using specialized, custom hardware most often found in computers from Silicon Graphics (SGI). We provided an alternative to expensive SGI hardware by taking advantage of third-party, 3-D graphics accelerators that have now become available at very affordable prices. To make use of this hardware our goal was to provide a free, redistributable, and fully-compatible OpenGL work-alike library so that existing bodies of code could simply be recompiled. for PC class machines running a free version of Unix. This should allow substantial cost savings while greatly expanding the population of people with access to a serious graphics development and viewing environment. This should offer a means for NASA to provide a spectrum of graphics performance to its scientists, supplying high-end specialized SGI hardware for high-performance visualization while fulfilling the requirements of medium and lower performance applications with generic, off-the-shelf components and still maintaining compatibility between the two.

  2. SPS phase control system performance via analytical simulation

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.; Booth, R. W. D.

    1979-01-01

    A solar power satellite transmission system which incorporates automatic beam forming, steering, and phase control is discussed. The phase control concept centers around the notation of an active retrodirective phased array as a means of pointing the beam to the appropriate spot on Earth. The transmitting antenna (spacetenna) directs the high power beam so that it focuses on the ground-based receiving antenna (rectenna). A combination of analysis and computerized simulation was conducted to determine the far field performance of the reference distribution system, and the beam forming and microwave power generating systems.

  3. Performance monitoring following conflict: internal adjustments in cognitive control?

    PubMed

    Larson, Michael J; Clayson, Peter E; Baldwin, Scott A

    2012-02-01

    The purpose of this study was to investigate the effects of strategic conflict-related adjustments in cognitive control processes on indices of performance monitoring. Previous research has examined the ability of parametric task-related manipulations to bias attention to errors; however, the present study sought to elucidate the effects of internal adjustments in control mediated by the anterior cingulate cortex on error-related conflict processing. High-density event-related potentials (ERPs) were obtained from 124 healthy individuals (68 female, 66 male) during a modified Eriksen flanker task. Behavioral measures (i.e., error rates, response times [RTs]) and N2 amplitudes showed significant conflict adaptation (i.e., previous-trial congruencies influenced current-trial measures). For error trials, the error-related negativity (ERN) was more negative for errors on high-conflict (i.e., incongruent) trials following high-conflict trials relative to errors on high-conflict trials following low-conflict (i.e., congruent) trials. These findings indicate that error-related conflict-monitoring processes adjust according to the post-conflict recruitment of strategic cognitive control and suggest an ongoing interplay between conflict and internal adjustments in control resources. Interpretations from the perspective of the conflict monitoring theory of cognitive control, the reinforcement learning theory, and the response-outcome theory of the ERN are discussed.

  4. Modeling-Error-Driven Performance-Seeking Direct Adaptive Control

    NASA Technical Reports Server (NTRS)

    Kulkarni, Nilesh V.; Kaneshige, John; Krishnakumar, Kalmanje; Burken, John

    2008-01-01

    This paper presents a stable discrete-time adaptive law that targets modeling errors in a direct adaptive control framework. The update law was developed in our previous work for the adaptive disturbance rejection application. The approach is based on the philosophy that without modeling errors, the original control design has been tuned to achieve the desired performance. The adaptive control should, therefore, work towards getting this performance even in the face of modeling uncertainties/errors. In this work, the baseline controller uses dynamic inversion with proportional-integral augmentation. Dynamic inversion is carried out using the assumed system model. On-line adaptation of this control law is achieved by providing a parameterized augmentation signal to the dynamic inversion block. The parameters of this augmentation signal are updated to achieve the nominal desired error dynamics. Contrary to the typical Lyapunov-based adaptive approaches that guarantee only stability, the current approach investigates conditions for stability as well as performance. A high-fidelity F-15 model is used to illustrate the overall approach.

  5. An Introduction to High Performance Computing

    NASA Astrophysics Data System (ADS)

    Almeida, Sérgio

    2013-09-01

    High Performance Computing (HPC) has become an essential tool in every researcher's arsenal. Most research problems nowadays can be simulated, clarified or experimentally tested by using computational simulations. Researchers struggle with computational problems when they should be focusing on their research problems. Since most researchers have little-to-no knowledge in low-level computer science, they tend to look at computer programs as extensions of their minds and bodies instead of completely autonomous systems. Since computers do not work the same way as humans, the result is usually Low Performance Computing where HPC would be expected.

  6. Rotordynamic Instability Problems in High-Performance Turbomachinery

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Diagnostic and remedial methods concerning rotordynamic instability problems in high performance turbomachinery are discussed. Instabilities due to seal forces and work-fluid forces are identified along with those induced by rotor bearing systems. Several methods of rotordynamic control are described including active feedback methods, the use of elastometric elements, and the use of hydrodynamic journal bearings and supports.

  7. Design of a Performance-Adaptive PID Control System Based on Modeling Performance Assessment

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toru

    In industrial processes represented by petroleum and refinery processes, it is necessary to establish the performance-driven control strategy in order to improve the productivity, which the control performance is firstly evaluated, and the controller is reconstructed. This paper describes a design scheme of performance-adaptive PID controllers which are based on the above control mechanism. According to the proposed control scheme, the system identification works corresponding to the result of modeling performance assessment, and PID parameters are computed using the newly estimated system parameters. In calculating the PID parameters, the desired control performance is considered. The behaviour of the proposed control scheme is numerically examined in some simulation examples.

  8. Controller design and performance of the Spacelab instrument pointing system

    NASA Astrophysics Data System (ADS)

    Woelker, A.

    The Spacelab instrument pointing system (IPS) is designed for high-precision pointing of space experiments. The IPS demonstrated its performance during the maiden flight on the Shuttle in July 1985. The control system provides three-axis pointing and stabilization in the arcsec range for a variety of experiments. The envisaged pointing accuracy as well as the structural flexibility of the plant and disturbances imposed challenging requirements on the controller design. The control system comprises a feedback loop with attenuation filters and PID control as well as feed-forward compensation of external disturbances. Based on optical sensor and gyro measurements the attitude is determined via a special version of the Kalman filter.

  9. Toward a theory of high performance.

    PubMed

    Kirby, Julia

    2005-01-01

    What does it mean to be a high-performance company? The process of measuring relative performance across industries and eras, declaring top performers, and finding the common drivers of their success is such a difficult one that it might seem a fool's errand to attempt. In fact, no one did for the first thousand or so years of business history. The question didn't even occur to many scholars until Tom Peters and Bob Waterman released In Search of Excellence in 1982. Twenty-three years later, we've witnessed several more attempts--and, just maybe, we're getting closer to answers. In this reported piece, HBR senior editor Julia Kirby explores why it's so difficult to study high performance and how various research efforts--including those from John Kotter and Jim Heskett; Jim Collins and Jerry Porras; Bill Joyce, Nitin Nohria, and Bruce Roberson; and several others outlined in a summary chart-have attacked the problem. The challenge starts with deciding which companies to study closely. Are the stars the ones with the highest market caps, the ones with the greatest sales growth, or simply the ones that remain standing at the end of the game? (And when's the end of the game?) Each major study differs in how it defines success, which companies it therefore declares to be worthy of emulation, and the patterns of activity and attitude it finds in common among them. Yet, Kirby concludes, as each study's method incrementally solves problems others have faced, we are progressing toward a consensus theory of high performance. PMID:16028814

  10. Design of high performance piezo composites actuators

    NASA Astrophysics Data System (ADS)

    Almajid, Abdulhakim A.

    Design of high performance piezo composites actuators are developed. Functionally Graded Microstructure (FGM) piezoelectric actuators are designed to reduce the stress concentration at the middle interface existed in the standard bimorph actuators while maintaining high actuation performance. The FGM piezoelectric laminates are composite materials with electroelastic properties varied through the laminate thickness. The elastic behavior of piezo-laminates actuators is developed using a 2D-elasticity model and a modified classical lamination theory (CLT). The stresses and out-of-plane displacements are obtained for standard and FGM piezoelectric bimorph plates under cylindrical bending generated by an electric field throughout the thickness of the laminate. The analytical model is developed for two different actuator geometries, a rectangular plate actuator and a disk shape actuator. The limitations of CLT are investigated against the 2D-elasticity model for the rectangular plate geometry. The analytical models based on CLT (rectangular and circular) and 2D-elasticity are compared with a model based on Finite Element Method (FEM). The experimental study consists of two FGM actuator systems, the PZT/PZT FGM system and the porous FGM system. The electroelastic properties of each layer in the FGM systems were measured and input in the analytical models to predict the FGM actuator performance. The performance of the FGM actuator is optimized by manipulating the thickness of each layer in the FGM system. The thickness of each layer in the FGM system is made to vary in a linear or non-linear manner to achieve the best performance of the FGM piezoelectric actuator. The analytical and FEM results are found to agree well with the experimental measurements for both rectangular and disk actuators. CLT solutions are found to coincide well with the elasticity solutions for high aspect ratios while the CLT solutions gave poor results compared to the 2D elasticity solutions for

  11. Monitoring SLAC High Performance UNIX Computing Systems

    SciTech Connect

    Lettsome, Annette K.; /Bethune-Cookman Coll. /SLAC

    2005-12-15

    Knowledge of the effectiveness and efficiency of computers is important when working with high performance systems. The monitoring of such systems is advantageous in order to foresee possible misfortunes or system failures. Ganglia is a software system designed for high performance computing systems to retrieve specific monitoring information. An alternative storage facility for Ganglia's collected data is needed since its default storage system, the round-robin database (RRD), struggles with data integrity. The creation of a script-driven MySQL database solves this dilemma. This paper describes the process took in the creation and implementation of the MySQL database for use by Ganglia. Comparisons between data storage by both databases are made using gnuplot and Ganglia's real-time graphical user interface.

  12. Evaluation of high-performance computing software

    SciTech Connect

    Browne, S.; Dongarra, J.; Rowan, T.

    1996-12-31

    The absence of unbiased and up to date comparative evaluations of high-performance computing software complicates a user`s search for the appropriate software package. The National HPCC Software Exchange (NHSE) is attacking this problem using an approach that includes independent evaluations of software, incorporation of author and user feedback into the evaluations, and Web access to the evaluations. We are applying this approach to the Parallel Tools Library (PTLIB), a new software repository for parallel systems software and tools, and HPC-Netlib, a high performance branch of the Netlib mathematical software repository. Updating the evaluations with feed-back and making it available via the Web helps ensure accuracy and timeliness, and using independent reviewers produces unbiased comparative evaluations difficult to find elsewhere.

  13. Stability and Performance Metrics for Adaptive Flight Control

    NASA Technical Reports Server (NTRS)

    Stepanyan, Vahram; Krishnakumar, Kalmanje; Nguyen, Nhan; VanEykeren, Luarens

    2009-01-01

    This paper addresses the problem of verifying adaptive control techniques for enabling safe flight in the presence of adverse conditions. Since the adaptive systems are non-linear by design, the existing control verification metrics are not applicable to adaptive controllers. Moreover, these systems are in general highly uncertain. Hence, the system's characteristics cannot be evaluated by relying on the available dynamical models. This necessitates the development of control verification metrics based on the system's input-output information. For this point of view, a set of metrics is introduced that compares the uncertain aircraft's input-output behavior under the action of an adaptive controller to that of a closed-loop linear reference model to be followed by the aircraft. This reference model is constructed for each specific maneuver using the exact aerodynamic and mass properties of the aircraft to meet the stability and performance requirements commonly accepted in flight control. The proposed metrics are unified in the sense that they are model independent and not restricted to any specific adaptive control methods. As an example, we present simulation results for a wing damaged generic transport aircraft with several existing adaptive controllers.

  14. High performance microsystem packaging: A perspective

    SciTech Connect

    Romig, A.D. Jr.; Dressendorfer, P.V.; Palmer, D.W.

    1997-10-01

    The second silicon revolution will be based on intelligent, integrated microsystems where multiple technologies (such as analog, digital, memory, sensor, micro-electro-mechanical, and communication devices) are integrated onto a single chip or within a multichip module. A necessary element for such systems is cost-effective, high-performance packaging. This paper examines many of the issues associated with the packaging of integrated microsystems, with an emphasis on the areas of packaging design, manufacturability, and reliability.

  15. High Performance Databases For Scientific Applications

    NASA Technical Reports Server (NTRS)

    French, James C.; Grimshaw, Andrew S.

    1997-01-01

    The goal for this task is to develop an Extensible File System (ELFS). ELFS attacks the problem of the following: 1. Providing high bandwidth performance architectures; 2. Reducing the cognitive burden faced by applications programmers when they attempt to optimize; and 3. Seamlessly managing the proliferation of data formats and architectural differences. The approach for ELFS solution consists of language and run-time system support that permits the specification on a hierarchy of file classes.

  16. Tough, High-Performance, Thermoplastic Addition Polymers

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H.; Proctor, K. Mason; Gleason, John; Morgan, Cassandra; Partos, Richard

    1991-01-01

    Series of addition-type thermoplastics (ATT's) exhibit useful properties. Because of their addition curing and linear structure, ATT polymers have toughness, like thermoplastics, and easily processed, like thermosets. Work undertaken to develop chemical reaction forming stable aromatic rings in backbone of ATT polymer, combining high-temperature performance and thermo-oxidative stability with toughness and easy processibility, and minimizing or eliminating necessity for tradeoffs among properties often observed in conventional polymer syntheses.

  17. High temperature furnace modeling and performance verifications

    NASA Technical Reports Server (NTRS)

    Smith, James E., Jr.

    1992-01-01

    Analytical, numerical, and experimental studies were performed on two classes of high temperature materials processing sources for their potential use as directional solidification furnaces. The research concentrated on a commercially available high temperature furnace using a zirconia ceramic tube as the heating element and an Arc Furnace based on a tube welder. The first objective was to assemble the zirconia furnace and construct parts needed to successfully perform experiments. The 2nd objective was to evaluate the zirconia furnace performance as a directional solidification furnace element. The 3rd objective was to establish a data base on materials used in the furnace construction, with particular emphasis on emissivities, transmissivities, and absorptivities as functions of wavelength and temperature. A 1-D and 2-D spectral radiation heat transfer model was developed for comparison with standard modeling techniques, and were used to predict wall and crucible temperatures. The 4th objective addressed the development of a SINDA model for the Arc Furnace and was used to design sample holders and to estimate cooling media temperatures for the steady state operation of the furnace. And, the 5th objective addressed the initial performance evaluation of the Arc Furnace and associated equipment for directional solidification. Results of these objectives are presented.

  18. Performance and robustness of hybrid model predictive control for controllable dampers in building models

    NASA Astrophysics Data System (ADS)

    Johnson, Erik A.; Elhaddad, Wael M.; Wojtkiewicz, Steven F.

    2016-04-01

    A variety of strategies have been developed over the past few decades to determine controllable damping device forces to mitigate the response of structures and mechanical systems to natural hazards and other excitations. These "smart" damping devices produce forces through passive means but have properties that can be controlled in real time, based on sensor measurements of response across the structure, to dramatically reduce structural motion by exploiting more than the local "information" that is available to purely passive devices. A common strategy is to design optimal damping forces using active control approaches and then try to reproduce those forces with the smart damper. However, these design forces, for some structures and performance objectives, may achieve high performance by selectively adding energy, which cannot be replicated by a controllable damping device, causing the smart damper performance to fall far short of what an active system would provide. The authors have recently demonstrated that a model predictive control strategy using hybrid system models, which utilize both continuous and binary states (the latter to capture the switching behavior between dissipative and non-dissipative forces), can provide reductions in structural response on the order of 50% relative to the conventional clipped-optimal design strategy. This paper explores the robustness of this newly proposed control strategy through evaluating controllable damper performance when the structure model differs from the nominal one used to design the damping strategy. Results from the application to a two-degree-of-freedom structure model confirms the robustness of the proposed strategy.

  19. Computational Biology and High Performance Computing 2000

    SciTech Connect

    Simon, Horst D.; Zorn, Manfred D.; Spengler, Sylvia J.; Shoichet, Brian K.; Stewart, Craig; Dubchak, Inna L.; Arkin, Adam P.

    2000-10-19

    The pace of extraordinary advances in molecular biology has accelerated in the past decade due in large part to discoveries coming from genome projects on human and model organisms. The advances in the genome project so far, happening well ahead of schedule and under budget, have exceeded any dreams by its protagonists, let alone formal expectations. Biologists expect the next phase of the genome project to be even more startling in terms of dramatic breakthroughs in our understanding of human biology, the biology of health and of disease. Only today can biologists begin to envision the necessary experimental, computational and theoretical steps necessary to exploit genome sequence information for its medical impact, its contribution to biotechnology and economic competitiveness, and its ultimate contribution to environmental quality. High performance computing has become one of the critical enabling technologies, which will help to translate this vision of future advances in biology into reality. Biologists are increasingly becoming aware of the potential of high performance computing. The goal of this tutorial is to introduce the exciting new developments in computational biology and genomics to the high performance computing community.

  20. Optimizing the design of very high power, high performance converters

    SciTech Connect

    Edwards, R J; Tiagha, E A; Ganetis, G; Nawrocky, R J

    1980-01-01

    This paper describes how various technologies are used to achieve the desired performance in a high current magnet power converter system. It is hoped that the discussions of the design approaches taken will be applicable to other power supply systems where stringent requirements in stability, accuracy and reliability must be met.

  1. Multileaf collimator performance monitoring and improvement using semiautomated quality control testing and statistical process control

    SciTech Connect

    Létourneau, Daniel McNiven, Andrea; Keller, Harald; Wang, An; Amin, Md Nurul; Pearce, Jim; Norrlinger, Bernhard; Jaffray, David A.

    2014-12-15

    Purpose: High-quality radiation therapy using highly conformal dose distributions and image-guided techniques requires optimum machine delivery performance. In this work, a monitoring system for multileaf collimator (MLC) performance, integrating semiautomated MLC quality control (QC) tests and statistical process control tools, was developed. The MLC performance monitoring system was used for almost a year on two commercially available MLC models. Control charts were used to establish MLC performance and assess test frequency required to achieve a given level of performance. MLC-related interlocks and servicing events were recorded during the monitoring period and were investigated as indicators of MLC performance variations. Methods: The QC test developed as part of the MLC performance monitoring system uses 2D megavoltage images (acquired using an electronic portal imaging device) of 23 fields to determine the location of the leaves with respect to the radiation isocenter. The precision of the MLC performance monitoring QC test and the MLC itself was assessed by detecting the MLC leaf positions on 127 megavoltage images of a static field. After initial calibration, the MLC performance monitoring QC test was performed 3–4 times/week over a period of 10–11 months to monitor positional accuracy of individual leaves for two different MLC models. Analysis of test results was performed using individuals control charts per leaf with control limits computed based on the measurements as well as two sets of specifications of ±0.5 and ±1 mm. Out-of-specification and out-of-control leaves were automatically flagged by the monitoring system and reviewed monthly by physicists. MLC-related interlocks reported by the linear accelerator and servicing events were recorded to help identify potential causes of nonrandom MLC leaf positioning variations. Results: The precision of the MLC performance monitoring QC test and the MLC itself was within ±0.22 mm for most MLC leaves

  2. High Performance High-Tc Superconducting Wires

    SciTech Connect

    Kang, Sukill; Goyal, Amit; Li, Jing; Gapud, Albert Agcaoili; Martin, Patrick M; Heatherly Jr, Lee; Thompson, James R; Christen, David K; List III, Frederick Alyious; Paranthaman, Mariappan Parans; Lee, Dominic F

    2006-01-01

    We demonstrated short segments of a superconducting wire that meets or exceeds performance requirements for many large-scale applications of high-temperature superconducting materials, especially those requiring a high supercurrent and/or a high engineering critical current density in applied magnetic fields. The performance requirements for these varied applications were met in 3-micrometer-thick YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films epitaxially grown via pulsed laser ablation on rolling assisted biaxially textured substrates. Enhancements of the critical current in self-field as well as excellent retention of this current in high applied magnetic fields were achieved in the thick films via incorporation of a periodic array of extended columnar defects, composed of self-aligned nanodots of nonsuperconducting material extending through the entire thickness of the film. These columnar defects are highly effective in pinning the superconducting vortices or flux lines, thereby resulting in the substantially enhanced performance of this wire.

  3. High Performance Oxides-Based Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Ren, Guangkun; Lan, Jinle; Zeng, Chengcheng; Liu, Yaochun; Zhan, Bin; Butt, Sajid; Lin, Yuan-Hua; Nan, Ce-Wen

    2015-01-01

    Thermoelectric materials have attracted much attention due to their applications in waste-heat recovery, power generation, and solid state cooling. In comparison with thermoelectric alloys, oxide semiconductors, which are thermally and chemically stable in air at high temperature, are regarded as the candidates for high-temperature thermoelectric applications. However, their figure-of-merit ZT value has remained low, around 0.1-0.4 for more than 20 years. The poor performance in oxides is ascribed to the low electrical conductivity and high thermal conductivity. Since the electrical transport properties in these thermoelectric oxides are strongly correlated, it is difficult to improve both the thermoelectric power and electrical conductivity simultaneously by conventional methods. This review summarizes recent progresses on high-performance oxide-based thermoelectric bulk-materials including n-type ZnO, SrTiO3, and In2O3, and p-type Ca3Co4O9, BiCuSeO, and NiO, enhanced by heavy-element doping, band engineering and nanostructuring.

  4. The path toward HEP High Performance Computing

    NASA Astrophysics Data System (ADS)

    Apostolakis, John; Brun, René; Carminati, Federico; Gheata, Andrei; Wenzel, Sandro

    2014-06-01

    High Energy Physics code has been known for making poor use of high performance computing architectures. Efforts in optimising HEP code on vector and RISC architectures have yield limited results and recent studies have shown that, on modern architectures, it achieves a performance between 10% and 50% of the peak one. Although several successful attempts have been made to port selected codes on GPUs, no major HEP code suite has a "High Performance" implementation. With LHC undergoing a major upgrade and a number of challenging experiments on the drawing board, HEP cannot any longer neglect the less-than-optimal performance of its code and it has to try making the best usage of the hardware. This activity is one of the foci of the SFT group at CERN, which hosts, among others, the Root and Geant4 project. The activity of the experiments is shared and coordinated via a Concurrency Forum, where the experience in optimising HEP code is presented and discussed. Another activity is the Geant-V project, centred on the development of a highperformance prototype for particle transport. Achieving a good concurrency level on the emerging parallel architectures without a complete redesign of the framework can only be done by parallelizing at event level, or with a much larger effort at track level. Apart the shareable data structures, this typically implies a multiplication factor in terms of memory consumption compared to the single threaded version, together with sub-optimal handling of event processing tails. Besides this, the low level instruction pipelining of modern processors cannot be used efficiently to speedup the program. We have implemented a framework that allows scheduling vectors of particles to an arbitrary number of computing resources in a fine grain parallel approach. The talk will review the current optimisation activities within the SFT group with a particular emphasis on the development perspectives towards a simulation framework able to profit best from

  5. [High-performance society and doping].

    PubMed

    Gallien, C L

    2002-09-01

    Doping is not limited to high-level athletes. Likewise it is not limited to the field of sports activities. The doping phenomenon observed in sports actually reveals an underlying question concerning the notion of sports itself, and more widely, the society's conception of sports. In a high-performance society, which is also a high-risk society, doping behavior is observed in a large number of persons who may or may not participate in sports activities. The motivation is the search for individual success or profit. The fight against doping must therefore focus on individual responsibility and prevention in order to preserve athlete's health and maintain the ethical and educational value of sports activities.

  6. High Performance Fortran for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush; Zima, Hans; Bushnell, Dennis M. (Technical Monitor)

    2000-01-01

    This paper focuses on the use of High Performance Fortran (HPF) for important classes of algorithms employed in aerospace applications. HPF is a set of Fortran extensions designed to provide users with a high-level interface for programming data parallel scientific applications, while delegating to the compiler/runtime system the task of generating explicitly parallel message-passing programs. We begin by providing a short overview of the HPF language. This is followed by a detailed discussion of the efficient use of HPF for applications involving multiple structured grids such as multiblock and adaptive mesh refinement (AMR) codes as well as unstructured grid codes. We focus on the data structures and computational structures used in these codes and on the high-level strategies that can be expressed in HPF to optimally exploit the parallelism in these algorithms.

  7. Heavily Doped PBSE with High Thermoelectric Performance

    NASA Technical Reports Server (NTRS)

    Snyder, G. Jeffrey (Inventor); Wang, Heng (Inventor); Pei, Yanzhong (Inventor)

    2015-01-01

    The present invention discloses heavily doped PbSe with high thermoelectric performance. Thermoelectric property measurements disclosed herein indicated that PbSe is high zT material for mid-to-high temperature thermoelectric applications. At 850 K a peak zT (is) greater than 1.3 was observed when n(sub H) approximately 1.0 X 10(exp 20) cm(exp -3). The present invention also discloses that a number of strategies used to improve zT of PbTe, such as alloying with other elements, nanostructuring and band modification may also be used to further improve zT in PbSe.

  8. Nonlinear feedback control for high alpha flight

    NASA Technical Reports Server (NTRS)

    Stalford, Harold

    1990-01-01

    Analytical aerodynamic models are derived from a high alpha 6 DOF wind tunnel model. One detail model requires some interpolation between nonlinear functions of alpha. One analytical model requires no interpolation and as such is a completely continuous model. Flight path optimization is conducted on the basic maneuvers: half-loop, 90 degree pitch-up, and level turn. The optimal control analysis uses the derived analytical model in the equations of motion and is based on both moment and force equations. The maximum principle solution for the half-loop is poststall trajectory performing the half-loop in 13.6 seconds. The agility induced by thrust vectoring capability provided a minimum effect on reducing the maneuver time. By means of thrust vectoring control the 90 degrees pitch-up maneuver can be executed in a small place over a short time interval. The agility capability of thrust vectoring is quite beneficial for pitch-up maneuvers. The level turn results are based currently on only outer layer solutions of singular perturbation. Poststall solutions provide high turn rates but generate higher losses of energy than that of classical sustained solutions.

  9. Lithography imaging control by enhanced monitoring of light source performance

    NASA Astrophysics Data System (ADS)

    Alagna, Paolo; Zurita, Omar; Lalovic, Ivan; Seong, Nakgeuon; Rechsteiner, Gregory; Thornes, Joshua; D'havé, Koen; Van Look, Lieve; Bekaert, Joost

    2013-04-01

    Reducing lithography pattern variability has become a critical enabler of ArF immersion scaling and is required to ensure consistent lithography process yield for sub-30nm device technologies. As DUV multi-patterning requirements continue to shrink, it is imperative that all sources of lithography variability are controlled throughout the product life-cycle, from technology development to high volume manufacturing. Recent developments of new ArF light-source metrology and monitoring capabilities have been introduced in order to improve lithography patterning control.[1] These technologies enable performance monitoring of new light-source properties, relating to illumination stability, and enable new reporting and analysis of in-line performance.

  10. Performance of annular high frequency thermoacoustic engines

    NASA Astrophysics Data System (ADS)

    Rodriguez, Ivan A.

    This thesis presents studies of the behavior of miniature annular thermoacoustic prime movers and the imaging of the complex sound fields using PIV inside the small acoustic wave guides when driven by a temperature gradient. Thermoacoustic engines operating in the standing wave mode are limited in their acoustic efficiency by a high degree of irreversibility that is inherent in how they work. Better performance can be achieved by using traveling waves in the thermoacoustic devices. This has led to the development of an annular high frequency thermoacoustic prime mover consisting of a regenerator, which is a random stack in-between a hot and cold heat exchanger, inside an annular waveguide. Miniature devices were developed and studied with operating frequencies in the range of 2-4 kHz. This corresponds to an average ring circumference of 11 cm for the 3 kHz device, the resonator bore being 6 mm. A similar device of 11 mm bore, length of 18 cm was also investigated; its resonant frequency was 2 kHz. Sound intensities as high as 166.8 dB were generated with limited heat input. Sound power was extracted from the annular structure by an impedance-matching side arm. The nature of the acoustic wave generated by heat was investigated using a high speed PIV instrument. Although the acoustic device appears symmetric, its performance is characterized by a broken symmetry and by perturbations that exist in its structure. Effects of these are observed in the PIV imaging; images show axial and radial components. Moreover, PIV studies show effects of streaming and instabilities which affect the devices' acoustic efficiency. The acoustic efficiency is high, being of 40% of Carnot. This type of device shows much promise as a high efficiency energy converter; it can be reduced in size for microcircuit applications.

  11. High capacity heat pipe performance demonstration

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A high capacity heat pipe which will operate in one-g and in zero-g is investigated. An artery configuration which is self-priming in one-g was emphasized. Two artery modifications were evolved as candidates to achieve one-g priming and will provide the very high performance: the four artery and the eight artery configurations. These were each evaluated analytically for performance and priming capability. The eight artery configuration was found to be inadequate from a performance standpoint. The four artery showed promise of working. A five-inch long priming element test article was fabricated using the four artery design. Plexiglas viewing windows were made on each end of the heat pipe to permit viewing of the priming activity. The five-inch primary element would not successfully prime in one-g. Difficulties on priming in one-g raised questions about zero-g priming. Therefore a small test element heat pipe for verifying that the proposed configuration will self-prime in zero-g was fabricated and delivered.

  12. A High Performance COTS Based Computer Architecture

    NASA Astrophysics Data System (ADS)

    Patte, Mathieu; Grimoldi, Raoul; Trautner, Roland

    2014-08-01

    Using Commercial Off The Shelf (COTS) electronic components for space applications is a long standing idea. Indeed the difference in processing performance and energy efficiency between radiation hardened components and COTS components is so important that COTS components are very attractive for use in mass and power constrained systems. However using COTS components in space is not straightforward as one must account with the effects of the space environment on the COTS components behavior. In the frame of the ESA funded activity called High Performance COTS Based Computer, Airbus Defense and Space and its subcontractor OHB CGS have developed and prototyped a versatile COTS based architecture for high performance processing. The rest of the paper is organized as follows: in a first section we will start by recapitulating the interests and constraints of using COTS components for space applications; then we will briefly describe existing fault mitigation architectures and present our solution for fault mitigation based on a component called the SmartIO; in the last part of the paper we will describe the prototyping activities executed during the HiP CBC project.

  13. Performance of silvered Teflon (trademark) thermal control blankets on spacecraft

    NASA Technical Reports Server (NTRS)

    Pippin, Gary; Stuckey, Wayne; Hemminger, Carol

    1993-01-01

    Silverized Teflon (Ag/FEP) is a widely used passive thermal control material for space applications. The material has a very low alpha/e ratio (less than 0.1) for low operating temperatures and is fabricated with various FEP thicknesses (as the Teflon thickness increases, the emittance increases). It is low outgassing and, because of its flexibility, can be applied around complex, curved shapes. Ag/FEP has achieved multiyear lifetimes under a variety of exposure conditions. This has been demonstrated by the Long Duration Exposure Facility (LDEF), Solar Max, Spacecraft Charging at High Altitudes (SCATHA), and other flight experiments. Ag/FEP material has been held in place on spacecraft by a variety of methods: mechanical clamping, direct adhesive bonding of tapes and sheets, and by Velcro(TM) tape adhesively bonded to back surfaces. On LDEF, for example, 5-mil blankets held by Velcro(TM) and clamping were used for thermal control over 3- by 4-ft areas on each of 17 trays. Adhesively bonded 2- and 5-mil sheets were used on other LDEF experiments, both for thermal control and as tape to hold other thermal control blankets in place. Performance data over extended time periods are available from a number of flights. The observed effects on optical properties, mechanical properties, and surface chemistry will be summarized in this paper. This leads to a discussion of performance life estimates and other design lessons for Ag/FEP thermal control material.

  14. ControlNet features high speed

    SciTech Connect

    McEldowney, D.

    1996-11-01

    ControlNet is a high-speed, high-capacity network providing a connection among controllers and I/O subsystems. It was designed for applications in which data integrity, determinism, high speeds, and high data capacities are required. ControlNet addresses applications needing tighter control over processes as well as demanding remote I/O or interlocked PLC applications, both discrete- and process-related. Some examples include high-speed conveyors, transfer lines, cut-to-length lines, high-speed assembly, bottling, and packaging. Process examples, or those typically requiring heavy remote analog I/O, include water/wastewater, test stands, chemical, beverage, food, marine control, and utility balance-of-plant.

  15. Performance of the CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Perrotta, Andrea

    2015-12-01

    The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level is the so-called High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increases in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. The increase in the number of interactions per bunch crossing, on average 25 in 2012, and expected to be around 40 in Run II, will be an additional complication. We present here the expected performance of the main triggers that will be used during the 2015 data taking campaign, paying particular attention to the new approaches that have been developed to cope with the challenges of the new run. This includes improvements in HLT electron and photon reconstruction as well as better performing muon triggers. We will also present the performance of the improved tracking and vertexing algorithms, discussing their impact on the b-tagging performance as well as on the jet and missing energy reconstruction.

  16. RISC Processors and High Performance Computing

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Bailey, David H.; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    In this tutorial, we will discuss top five current RISC microprocessors: The IBM Power2, which is used in the IBM RS6000/590 workstation and in the IBM SP2 parallel supercomputer, the DEC Alpha, which is in the DEC Alpha workstation and in the Cray T3D; the MIPS R8000, which is used in the SGI Power Challenge; the HP PA-RISC 7100, which is used in the HP 700 series workstations and in the Convex Exemplar; and the Cray proprietary processor, which is used in the new Cray J916. The architecture of these microprocessors will first be presented. The effective performance of these processors will then be compared, both by citing standard benchmarks and also in the context of implementing a real applications. In the process, different programming models such as data parallel (CM Fortran and HPF) and message passing (PVM and MPI) will be introduced and compared. The latest NAS Parallel Benchmark (NPB) absolute performance and performance per dollar figures will be presented. The next generation of the NP13 will also be described. The tutorial will conclude with a discussion of general trends in the field of high performance computing, including likely future developments in hardware and software technology, and the relative roles of vector supercomputers tightly coupled parallel computers, and clusters of workstations. This tutorial will provide a unique cross-machine comparison not available elsewhere.

  17. Towards high performance inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Gong, Xiong

    2013-03-01

    Bulk heterojunction polymer solar cells that can be fabricated by solution processing techniques are under intense investigation in both academic institutions and industrial companies because of their potential to enable mass production of flexible and cost-effective alternative to silicon-based electronics. Despite the envisioned advantages and recent technology advances, so far the performance of polymer solar cells is still inferior to inorganic counterparts in terms of the efficiency and stability. There are many factors limiting the performance of polymer solar cells. Among them, the optical and electronic properties of materials in the active layer, device architecture and elimination of PEDOT:PSS are the most determining factors in the overall performance of polymer solar cells. In this presentation, I will present how we approach high performance of polymer solar cells. For example, by developing novel materials, fabrication polymer photovoltaic cells with an inverted device structure and elimination of PEDOT:PSS, we were able to observe over 8.4% power conversion efficiency from inverted polymer solar cells.

  18. High-performance computing in seismology

    SciTech Connect

    1996-09-01

    The scientific, technical, and economic importance of the issues discussed here presents a clear agenda for future research in computational seismology. In this way these problems will drive advances in high-performance computing in the field of seismology. There is a broad community that will benefit from this work, including the petroleum industry, research geophysicists, engineers concerned with seismic hazard mitigation, and governments charged with enforcing a comprehensive test ban treaty. These advances may also lead to new applications for seismological research. The recent application of high-resolution seismic imaging of the shallow subsurface for the environmental remediation industry is an example of this activity. This report makes the following recommendations: (1) focused efforts to develop validated documented software for seismological computations should be supported, with special emphasis on scalable algorithms for parallel processors; (2) the education of seismologists in high-performance computing technologies and methodologies should be improved; (3) collaborations between seismologists and computational scientists and engineers should be increased; (4) the infrastructure for archiving, disseminating, and processing large volumes of seismological data should be improved.

  19. High Power MPD Thruster Performance Measurements

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Strzempkowski, Eugene; Pencil, Eric

    2004-01-01

    High power magnetoplasmadynamic (MPD) thrusters are being developed as cost effective propulsion systems for cargo transport to lunar and Mars bases, crewed missions to Mars and the outer planets, and robotic deep space exploration missions. Electromagnetic MPD thrusters have demonstrated, at the laboratory level, the ability to process megawatts of electrical power while providing significantly higher thrust densities than electrostatic electric propulsion systems. The ability to generate higher thrust densities permits a reduction in the number of thrusters required to perform a given mission, and alleviates the system complexity associated with multiple thruster arrays. The specific impulse of an MPD thruster can be optimized to meet given mission requirements, from a few thousand seconds with heavier gas propellants up to 10,000 seconds with hydrogen propellant. In support of programs envisioned by the NASA Office of Exploration Systems, Glenn Research Center is developing and testing quasi-steady MW-class MPD thrusters as a prelude to steady state high power thruster tests. This paper provides an overview of the GRC high power pulsed thruster test facility, and presents preliminary performance data for a quasi-steady baseline MPD thruster geometry.

  20. Arteriopathy in the high-performance athlete.

    PubMed

    Takach, Thomas J; Kane, Peter N; Madjarov, Jeko M; Holleman, Jeremiah H; Nussbaum, Tzvi; Robicsek, Francis; Roush, Timothy S

    2006-01-01

    Pain occurs frequently in high-performance athletes and is most often due to musculoskeletal injury or strain. However, athletes who participate in sports that require highly frequent, repetitive limb motion can also experience pain from an underlying arteriopathy, which causes exercise-induced ischemia. We reviewed the clinical records and follow-up care of 3 high-performance athletes (mean age, 29.3 yr; range, 16-47 yr) who were admitted consecutively to our institution from January 2002 through May 2003, each with a diagnosis of limb ischemia due to arteriopathy. The study group comprised 3 males: 2 active in competitive baseball (ages, 16 and 19 yr) and a cyclist (age, 47 yr). Provocative testing and radiologic evaluation established the diagnoses. Treatment goals included targeted resection of compressive structures, arterial reconstruction to eliminate stenosis and possible emboli, and improvement of distal perfusion. Our successful reconstructive techniques included thoracic outlet decompression and interpositional bypass of the subclavian artery in the 16-year-old patient, pectoralis muscle and tendon decompression to relieve compression of the axillary artery in the 19-year-old, and patch angioplasty for endofibrosis affecting the external iliac artery in the 47-year-old. Each patient was asymptomatic on follow-up and had resumed participation in competitive athletics. The recognition and anatomic definition of an arteriopathy that produces exercise-induced ischemia enables the application of precise therapy that can produce a symptom-free outcome and the ability to resume competitive athletics.

  1. High performance robotic traverse of desert terrain.

    SciTech Connect

    Whittaker, William

    2004-09-01

    This report presents tentative innovations to enable unmanned vehicle guidance for a class of off-road traverse at sustained speeds greater than 30 miles per hour. Analyses and field trials suggest that even greater navigation speeds might be achieved. The performance calls for innovation in mapping, perception, planning and inertial-referenced stabilization of components, hosted aboard capable locomotion. The innovations are motivated by the challenge of autonomous ground vehicle traverse of 250 miles of desert terrain in less than 10 hours, averaging 30 miles per hour. GPS coverage is assumed to be available with localized blackouts. Terrain and vegetation are assumed to be akin to that of the Mojave Desert. This terrain is interlaced with networks of unimproved roads and trails, which are a key to achieving the high performance mapping, planning and navigation that is presented here.

  2. Enhancing supply chain performance with improved order-control policies

    NASA Astrophysics Data System (ADS)

    Nilakantan, K.

    2010-09-01

    This article takes up the study of the dynamics of a single product in a prototype three-stage supply chain system, at the downstream warehouse end of the chain, under a responsive chain strategy. The dynamics under various ordering policies and the parameters which will yield desired responses are systematically analysed, both for deterministic and stochastic systems. Higher-order control policies are then proposed and analysed. The considered key performance criteria are the permanent inventory deviations from the desired levels, or the offset, the maximum dip in inventory, the 'undershoot', the damping effect and decay rates, and the duration of time in the negative region, for deterministic systems; and additionally, the inventory variance for stochastic systems. It is shown that the disadvantages of the conventional (proportional-integral-derivative) control policies, like large negative deviations, low decay rates, and high inventory variance, can be overcome by the use of higher-order control policies proposed herein.

  3. The effects of bedrest on crew performance during simulated shuttle reentry. Volume 2: Control task performance

    NASA Technical Reports Server (NTRS)

    Jex, H. R.; Peters, R. A.; Dimarco, R. J.; Allen, R. W.

    1974-01-01

    A simplified space shuttle reentry simulation performed on the NASA Ames Research Center Centrifuge is described. Anticipating potentially deleterious effects of physiological deconditioning from orbital living (simulated here by 10 days of enforced bedrest) upon a shuttle pilot's ability to manually control his aircraft (should that be necessary in an emergency) a comprehensive battery of measurements was made roughly every 1/2 minute on eight military pilot subjects, over two 20-minute reentry Gz vs. time profiles, one peaking at 2 Gz and the other at 3 Gz. Alternate runs were made without and with g-suits to test the help or interference offered by such protective devices to manual control performance. A very demanding two-axis control task was employed, with a subcritical instability in the pitch axis to force a high attentional demand and a severe loss-of-control penalty. The results show that pilots experienced in high Gz flying can easily handle the shuttle manual control task during 2 Gz or 3 Gz reentry profiles, provided the degree of physiological deconditioning is no more than induced by these 10 days of enforced bedrest.

  4. Climate Modeling using High-Performance Computing

    SciTech Connect

    Mirin, A A

    2007-02-05

    The Center for Applied Scientific Computing (CASC) and the LLNL Climate and Carbon Science Group of Energy and Environment (E and E) are working together to improve predictions of future climate by applying the best available computational methods and computer resources to this problem. Over the last decade, researchers at the Lawrence Livermore National Laboratory (LLNL) have developed a number of climate models that provide state-of-the-art simulations on a wide variety of massively parallel computers. We are now developing and applying a second generation of high-performance climate models. Through the addition of relevant physical processes, we are developing an earth systems modeling capability as well.

  5. High Performance Piezoelectric Actuated Gimbal (HIERAX)

    SciTech Connect

    Charles Tschaggeny; Warren Jones; Eberhard Bamberg

    2007-04-01

    This paper presents a 3-axis gimbal whose three rotational axes are actuated by a novel drive system: linear piezoelectric motors whose linear output is converted to rotation by using drive disks. Advantages of this technology are: fast response, high accelerations, dither-free actuation and backlash-free positioning. The gimbal was developed to house a laser range finder for the purpose of tracking and guiding unmanned aerial vehicles during landing maneuvers. The tilt axis was built and the test results indicate excellent performance that meets design specifications.

  6. High-performance neural networks. [Neural computers

    SciTech Connect

    Dress, W.B.

    1987-06-01

    The new Forth hardware architectures offer an intermediate solution to high-performance neural networks while the theory and programming details of neural networks for synthetic intelligence are developed. This approach has been used successfully to determine the parameters and run the resulting network for a synthetic insect consisting of a 200-node ''brain'' with 1760 interconnections. Both the insect's environment and its sensor input have thus far been simulated. However, the frequency-coded nature of the Browning network allows easy replacement of the simulated sensors by real-world counterparts.

  7. High performance channel injection sealant invention abstract

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Basiulis, D. I.; Salisbury, D. P. (Inventor)

    1982-01-01

    High performance channel sealant is based on NASA patented cyano and diamidoximine-terminated perfluoroalkylene ether prepolymers that are thermally condensed and cross linked. The sealant contains asbestos and, in its preferred embodiments, Lithofrax, to lower its thermal expansion coefficient and a phenolic metal deactivator. Extensive evaluation shows the sealant is extremely resistant to thermal degradation with an onset point of 280 C. The materials have a volatile content of 0.18%, excellent flexibility, and adherence properties, and fuel resistance. No corrosibility to aluminum or titanium was observed.

  8. Initial performance of the High Speed Photometer

    NASA Technical Reports Server (NTRS)

    Richards, Evan; Percival, Jeff; Nelson, Matt; Hatter, ED; Fitch, John; White, Rick

    1991-01-01

    The Hubble Space Telescope High Speed Photometer has four image dissector tubes, two with UV sensitive photocathodes, two sensitive to the near UV and to visual light, and a single red sensitive photomultiplier tube. The HSP is capable of photometric measurements from 1200 to 7500 A with time resolution of 11 microseconds and has no moving parts. An initial analysis of the on-orbit engineering performance of the HSP is presented with changes in operating procedures resulting from the primary mirror spherical aberration and experience gained during the verification period.

  9. High-Performance Water-Iodinating Cartridge

    NASA Technical Reports Server (NTRS)

    Sauer, Richard; Gibbons, Randall E.; Flanagan, David T.

    1993-01-01

    High-performance cartridge contains bed of crystalline iodine iodinates water to near saturation in single pass. Cartridge includes stainless-steel housing equipped with inlet and outlet for water. Bed of iodine crystals divided into layers by polytetrafluoroethylene baffles. Holes made in baffles and positioned to maximize length of flow path through layers of iodine crystals. Resulting concentration of iodine biocidal; suppresses growth of microbes in stored water or disinfects contaminated equipment. Cartridge resists corrosion and can be stored wet. Reused several times before necessary to refill with fresh iodine crystals.

  10. High-temperature testing of high performance fiber reinforced concrete

    NASA Astrophysics Data System (ADS)

    Fořt, Jan; Vejmelková, Eva; Pavlíková, Milena; Trník, Anton; Čítek, David; Kolísko, Jiří; Černý, Robert; Pavlík, Zbyšek

    2016-06-01

    The effect of high-temperature exposure on properties of High Performance Fiber Reinforced Concrete (HPFRC) is researched in the paper. At first, reference measurements are done on HPFRC samples without high-temperature loading. Then, the HPFRC samples are exposed to the temperatures of 200, 400, 600, 800, and 1000 °C. For the temperature loaded samples, measurement of residual mechanical and basic physical properties is done. Linear thermal expansion coefficient as function of temperature is accessed on the basis of measured thermal strain data. Additionally, simultaneous difference scanning calorimetry (DSC) and thermogravimetry (TG) analysis is performed in order to observe and explain material changes at elevated temperature. It is found that the applied high temperature loading significantly increases material porosity due to the physical, chemical and combined damage of material inner structure, and negatively affects also the mechanical strength. Linear thermal expansion coefficient exhibits significant dependence on temperature and changes of material structure. The obtained data will find use as input material parameters for modelling the damage of HPFRC structures exposed to the fire and high temperature action.

  11. Performance calculation and simulation system of high energy laser weapon

    NASA Astrophysics Data System (ADS)

    Wang, Pei; Liu, Min; Su, Yu; Zhang, Ke

    2014-12-01

    High energy laser weapons are ready for some of today's most challenging military applications. Based on the analysis of the main tactical/technical index and combating process of high energy laser weapon, a performance calculation and simulation system of high energy laser weapon was established. Firstly, the index decomposition and workflow of high energy laser weapon was proposed. The entire system was composed of six parts, including classical target, platform of laser weapon, detect sensor, tracking and pointing control, laser atmosphere propagation and damage assessment module. Then, the index calculation modules were designed. Finally, anti-missile interception simulation was performed. The system can provide reference and basis for the analysis and evaluation of high energy laser weapon efficiency.

  12. High temperature furnace modeling and performance verifications

    NASA Technical Reports Server (NTRS)

    Smith, James E., Jr.

    1988-01-01

    Analytical, numerical and experimental studies were performed on two classes of high temperature materials processing furnaces. The research concentrates on a commercially available high temperature furnace using zirconia as the heating element and an arc furnace based on a ST International tube welder. The zirconia furnace was delivered and work is progressing on schedule. The work on the arc furnace was initially stalled due to the unavailability of the NASA prototype, which is actively being tested aboard the KC-135 experimental aircraft. A proposal was written and funded to purchase an additional arc welder to alleviate this problem. The ST International weld head and power supply were received and testing will begin in early November. The first 6 months of the grant are covered.

  13. Parallel Algebraic Multigrid Methods - High Performance Preconditioners

    SciTech Connect

    Yang, U M

    2004-11-11

    The development of high performance, massively parallel computers and the increasing demands of computationally challenging applications have necessitated the development of scalable solvers and preconditioners. One of the most effective ways to achieve scalability is the use of multigrid or multilevel techniques. Algebraic multigrid (AMG) is a very efficient algorithm for solving large problems on unstructured grids. While much of it can be parallelized in a straightforward way, some components of the classical algorithm, particularly the coarsening process and some of the most efficient smoothers, are highly sequential, and require new parallel approaches. This chapter presents the basic principles of AMG and gives an overview of various parallel implementations of AMG, including descriptions of parallel coarsening schemes and smoothers, some numerical results as well as references to existing software packages.

  14. High level intelligent control of telerobotics systems

    NASA Technical Reports Server (NTRS)

    Mckee, James

    1988-01-01

    A high level robot command language is proposed for the autonomous mode of an advanced telerobotics system and a predictive display mechanism for the teleoperational model. It is believed that any such system will involve some mixture of these two modes, since, although artificial intelligence can facilitate significant autonomy, a system that can resort to teleoperation will always have the advantage. The high level command language will allow humans to give the robot instructions in a very natural manner. The robot will then analyze these instructions to infer meaning so that is can translate the task into lower level executable primitives. If, however, the robot is unable to perform the task autonomously, it will switch to the teleoperational mode. The time delay between control movement and actual robot movement has always been a problem in teleoperations. The remote operator may not actually see (via a monitor) the results of high actions for several seconds. A computer generated predictive display system is proposed whereby the operator can see a real-time model of the robot's environment and the delayed video picture on the monitor at the same time.

  15. Initial Performance of the Keck AO Wavefront Controller System

    SciTech Connect

    Johansson, E M; Acton, D S; An, J R; Avicola, K; Beeman, B V; Brase, J M; Carrano, C J; Gathright, J; Gavel, D T; Hurd, R L; Lai, O; Lupton, W; Macintosh, B A; Max, C E; Olivier, S S; Shelton, J C; Stomski, P J; Tsubota, K; Waltjen, K E; Watson, J A; Wizinowich, P L

    2001-03-01

    The wavefront controller for the Keck Observatory AO system consists of two separate real-time control loops: a tip-tilt control loop to remove tilt from the incoming wavefront, and a deformable mirror control loop to remove higher-order aberrations. In this paper, we describe these control loops and analyze their performance using diagnostic data acquired during the integration and testing of the AO system on the telescope. Disturbance rejection curves for the controllers are calculated from the experimental data and compared to theory. The residual wavefront errors due to control loop bandwidth are also calculated from the data, and possible improvements to the controller performance are discussed.

  16. Concurrently adjusting interrelated control parameters to achieve optimal engine performance

    SciTech Connect

    Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

    2015-12-01

    Methods and systems for real-time engine control optimization are provided. A value of an engine performance variable is determined, a value of a first operating condition and a value of a second operating condition of a vehicle engine are detected, and initial values for a first engine control parameter and a second engine control parameter are determined based on the detected first operating condition and the detected second operating condition. The initial values for the first engine control parameter and the second engine control parameter are adjusted based on the determined value of the engine performance variable to cause the engine performance variable to approach a target engine performance variable. In order to cause the engine performance variable to approach the target engine performance variable, adjusting the initial value for the first engine control parameter necessitates a corresponding adjustment of the initial value for the second engine control parameter.

  17. High-performance mass storage system for workstations

    NASA Technical Reports Server (NTRS)

    Chiang, T.; Tang, Y.; Gupta, L.; Cooperman, S.

    1993-01-01

    Reduced Instruction Set Computer (RISC) workstations and Personnel Computers (PC) are very popular tools for office automation, command and control, scientific analysis, database management, and many other applications. However, when using Input/Output (I/O) intensive applications, the RISC workstations and PC's are often overburdened with the tasks of collecting, staging, storing, and distributing data. Also, by using standard high-performance peripherals and storage devices, the I/O function can still be a common bottleneck process. Therefore, the high-performance mass storage system, developed by Loral AeroSys' Independent Research and Development (IR&D) engineers, can offload a RISC workstation of I/O related functions and provide high-performance I/O functions and external interfaces. The high-performance mass storage system has the capabilities to ingest high-speed real-time data, perform signal or image processing, and stage, archive, and distribute the data. This mass storage system uses a hierarchical storage structure, thus reducing the total data storage cost, while maintaining high-I/O performance. The high-performance mass storage system is a network of low-cost parallel processors and storage devices. The nodes in the network have special I/O functions such as: SCSI controller, Ethernet controller, gateway controller, RS232 controller, IEEE488 controller, and digital/analog converter. The nodes are interconnected through high-speed direct memory access links to form a network. The topology of the network is easily reconfigurable to maximize system throughput for various applications. This high-performance mass storage system takes advantage of a 'busless' architecture for maximum expandability. The mass storage system consists of magnetic disks, a WORM optical disk jukebox, and an 8mm helical scan tape to form a hierarchical storage structure. Commonly used files are kept in the magnetic disk for fast retrieval. The optical disks are used as archive

  18. High-performance laboratories and cleanrooms

    SciTech Connect

    Tschudi, William; Sartor, Dale; Mills, Evan; Xu, Tengfang

    2002-07-01

    The California Energy Commission sponsored this roadmap to guide energy efficiency research and deployment for high performance cleanrooms and laboratories. Industries and institutions utilizing these building types (termed high-tech buildings) have played an important part in the vitality of the California economy. This roadmap's key objective to present a multi-year agenda to prioritize and coordinate research efforts. It also addresses delivery mechanisms to get the research products into the market. Because of the importance to the California economy, it is appropriate and important for California to take the lead in assessing the energy efficiency research needs, opportunities, and priorities for this market. In addition to the importance to California's economy, energy demand for this market segment is large and growing (estimated at 9400 GWH for 1996, Mills et al. 1996). With their 24hr. continuous operation, high tech facilities are a major contributor to the peak electrical demand. Laboratories and cleanrooms constitute the high tech building market, and although each building type has its unique features, they are similar in that they are extremely energy intensive, involve special environmental considerations, have very high ventilation requirements, and are subject to regulations--primarily safety driven--that tend to have adverse energy implications. High-tech buildings have largely been overlooked in past energy efficiency research. Many industries and institutions utilize laboratories and cleanrooms. As illustrated, there are many industries operating cleanrooms in California. These include semiconductor manufacturing, semiconductor suppliers, pharmaceutical, biotechnology, disk drive manufacturing, flat panel displays, automotive, aerospace, food, hospitals, medical devices, universities, and federal research facilities.

  19. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2006-03-14

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  20. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2008-03-25

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  1. High-performance vertical organic transistors.

    PubMed

    Kleemann, Hans; Günther, Alrun A; Leo, Karl; Lüssem, Björn

    2013-11-11

    Vertical organic thin-film transistors (VOTFTs) are promising devices to overcome the transconductance and cut-off frequency restrictions of horizontal organic thin-film transistors. The basic physical mechanisms of VOTFT operation, however, are not well understood and VOTFTs often require complex patterning techniques using self-assembly processes which impedes a future large-area production. In this contribution, high-performance vertical organic transistors comprising pentacene for p-type operation and C60 for n-type operation are presented. The static current-voltage behavior as well as the fundamental scaling laws of such transistors are studied, disclosing a remarkable transistor operation with a behavior limited by injection of charge carriers. The transistors are manufactured by photolithography, in contrast to other VOTFT concepts using self-assembled source electrodes. Fluorinated photoresist and solvent compounds allow for photolithographical patterning directly and strongly onto the organic materials, simplifying the fabrication protocol and making VOTFTs a prospective candidate for future high-performance applications of organic transistors. PMID:23637074

  2. Climate Modeling using High-Performance Computing

    SciTech Connect

    Mirin, A A; Wickett, M E; Duffy, P B; Rotman, D A

    2005-03-03

    The Center for Applied Scientific Computing (CASC) and the LLNL Atmospheric Science Division (ASD) are working together to improve predictions of future climate by applying the best available computational methods and computer resources to this problem. Over the last decade, researchers at the Lawrence Livermore National Laboratory (LLNL) have developed a number of climate models that provide state-of-the-art simulations on a wide variety of massively parallel computers. We are now developing and applying a second generation of high-performance climate models. As part of LLNL's participation in DOE's Scientific Discovery through Advanced Computing (SciDAC) program, members of CASC and ASD are collaborating with other DOE labs and NCAR in the development of a comprehensive, next-generation global climate model. This model incorporates the most current physics and numerics and capably exploits the latest massively parallel computers. One of LLNL's roles in this collaboration is the scalable parallelization of NASA's finite-volume atmospheric dynamical core. We have implemented multiple two-dimensional domain decompositions, where the different decompositions are connected by high-speed transposes. Additional performance is obtained through shared memory parallelization constructs and one-sided interprocess communication. The finite-volume dynamical core is particularly important to atmospheric chemistry simulations, where LLNL has a leading role.

  3. High-performance computing for airborne applications

    SciTech Connect

    Quinn, Heather M; Manuzzato, Andrea; Fairbanks, Tom; Dallmann, Nicholas; Desgeorges, Rose

    2010-06-28

    Recently, there has been attempts to move common satellite tasks to unmanned aerial vehicles (UAVs). UAVs are significantly cheaper to buy than satellites and easier to deploy on an as-needed basis. The more benign radiation environment also allows for an aggressive adoption of state-of-the-art commercial computational devices, which increases the amount of data that can be collected. There are a number of commercial computing devices currently available that are well-suited to high-performance computing. These devices range from specialized computational devices, such as field-programmable gate arrays (FPGAs) and digital signal processors (DSPs), to traditional computing platforms, such as microprocessors. Even though the radiation environment is relatively benign, these devices could be susceptible to single-event effects. In this paper, we will present radiation data for high-performance computing devices in a accelerated neutron environment. These devices include a multi-core digital signal processor, two field-programmable gate arrays, and a microprocessor. From these results, we found that all of these devices are suitable for many airplane environments without reliability problems.

  4. High Performance Computing CFRD -- Final Technial Report

    SciTech Connect

    Hope Forsmann; Kurt Hamman

    2003-01-01

    The Bechtel Waste Treatment Project (WTP), located in Richland, WA, is comprised of many processes containing complex physics. Accurate analyses of the underlying physics of these processes is needed to reduce the amount of added costs during and after construction that are due to unknown process behavior. The WTP will have tight operating margins in order to complete the treatment of the waste on schedule. The combination of tight operating constraints coupled with complex physical processes requires analysis methods that are more accurate than traditional approaches. This study is focused specifically on multidimensional computer aided solutions. There are many skills and tools required to solve engineering problems. Many physical processes are governed by nonlinear partial differential equations. These governing equations have few, if any, closed form solutions. Past and present solution methods require assumptions to reduce these equations to solvable forms. Computational methods take the governing equations and solve them directly on a computational grid. This ability to approach the equations in their exact form reduces the number of assumptions that must be made. This approach increases the accuracy of the solution and its applicability to the problem at hand. Recent advances in computer technology have allowed computer simulations to become an essential tool for problem solving. In order to perform computer simulations as quickly and accurately as possible, both hardware and software must be evaluated. With regards to hardware, the average consumer personal computers (PCs) are not configured for optimal scientific use. Only a few vendors create high performance computers to satisfy engineering needs. Software must be optimized for quick and accurate execution. Operating systems must utilize the hardware efficiently while supplying the software with seamless access to the computer’s resources. From the perspective of Bechtel Corporation and the Idaho

  5. Performance of fluidically controlled oscillating jet

    NASA Astrophysics Data System (ADS)

    Srinivas, T.; Vasudevan, B.; Prabhu, A.

    An experimental investigation on a fluidically controlled oscillating jet is reported. The flow inside the fluidic nozzle shows a feedback mechanism different from what is currently accepted. Although large spread angles can be obtained with fluidically oscillated jets, entrainment of secondary flow seems less than that in a steady jet.

  6. Locus of Control and Performance: Widening Applicabilities

    ERIC Educational Resources Information Center

    Manichander, T.

    2014-01-01

    In an attempt to explain the evidence which indicates that internal perception of control is positively related to academic achievement, this paper suggests that mediating motivational and cognitive reactions, which differentiate internals from externals, may account for this relationship. Furthermore, on the basis of data which suggest that the…

  7. Mariner Mars 1971 attitude control subsystem flight performance

    NASA Technical Reports Server (NTRS)

    Schumacher, L.

    1973-01-01

    The flight performance of the Mariner 71 attitude control subsystem is discussed. Each phase of the mission is delineated and the attitude control subsystem is evaluated within the observed operational environment. Performance anomalies are introduced and discussed within the context of general performance. Problems such as the sun sensor interface incompatibility, gas valve leaks, and scan platform dynamic coupling effects are given analytical considerations.

  8. Optimal control of 2-wheeled mobile robot at energy performance index

    NASA Astrophysics Data System (ADS)

    Kaliński, Krzysztof J.; Mazur, Michał

    2016-03-01

    The paper presents the application of the optimal control method at the energy performance index towards motion control of the 2-wheeled mobile robot. With the use of the proposed method of control the 2-wheeled mobile robot can realise effectively the desired trajectory. The problem of motion control of mobile robots is usually neglected and thus performance of the realisation of the high level control tasks is limited.

  9. Performance seeking control: Program overview and future directions

    NASA Technical Reports Server (NTRS)

    Gilyard, Glenn B.; Orme, John S.

    1993-01-01

    A flight test evaluation of the performance-seeking control (PSC) algorithm on the NASA F-15 highly integrated digital electronic control research aircraft was conducted for single-engine operation at subsonic and supersonic speeds. The model-based PSC system was developed with three optimization modes: minimum fuel flow at constant thrust, minimum turbine temperature at constant thrust, and maximum thrust at maximum dry and full afterburner throttle settings. Subsonic and supersonic flight testing were conducted at the NASA Dryden Flight Research Facility covering the three PSC optimization modes and over the full throttle range. Flight results show substantial benefits. In the maximum thrust mode, thrust increased up to 15 percent at subsonic and 10 percent at supersonic flight conditions. The minimum fan turbine inlet temperature mode reduced temperatures by more than 100 F at high altitudes. The minimum fuel flow mode results decreased fuel consumption up to 2 percent in the subsonic regime and almost 10 percent supersonically. These results demonstrate that PSC technology can benefit the next generation of fighter or transport aircraft. NASA Dryden is developing an adaptive aircraft performance technology system that is measurement based and uses feedback to ensure optimality. This program will address the technical weaknesses identified in the PSC program and will increase performance gains.

  10. Process Performance of Optima XEx Single Wafer High Energy Implanter

    SciTech Connect

    Kim, J. H.; Yoon, Jongyoon; Kondratenko, S.; David, J.; Rubin, L. M.; Jang, I. S.; Cha, J. C.; Joo, Y. H.; Lee, A. B.; Jin, S. W.

    2011-01-07

    To meet the process requirements for well formation in future CMOS memory production, high energy implanters require more robust angle, dose, and energy control while maintaining high productivity. The Optima XEx high energy implanter meets these requirements by integrating a traditional LINAC beamline with a robust single wafer handling system. To achieve beam angle control, Optima XEx can control both the horizontal and vertical beam angles to within 0.1 degrees using advanced beam angle measurement and correction. Accurate energy calibration and energy trim functions accelerate process matching by eliminating energy calibration errors. The large volume process chamber and UDC (upstream dose control) using faraday cups outside of the process chamber precisely control implant dose regardless of any chamber pressure increase due to PR (photoresist) outgassing. An optimized RF LINAC accelerator improves reliability and enables singly charged phosphorus and boron energies up to 1200 keV and 1500 keV respectively with higher beam currents. A new single wafer endstation combined with increased beam performance leads to overall increased productivity. We report on the advanced performance of Optima XEx observed during tool installation and volume production at an advanced memory fab.

  11. Flight controller alertness and performance during MOD shiftwork operations

    NASA Technical Reports Server (NTRS)

    Kelly, Sean M.; Rosekind, Mark R.; Dinges, David F.; Miller, Donna L.; Gillen, Kelly A.; Gregory, Kevin B.; Aguilar, Ronald D.; Smith, Roy M.

    1994-01-01

    Decreased alertness and performance associated with fatigue, sleep loss, and circadian disruption are issues faced by a diverse range of shiftwork operations. During STS operations, MOD personnel provide 24 hr. coverage of critical tasks. A joint JSC and ARC project was undertaken to examine these issues in flight controllers during MOD shiftwork operations. An initial operational test of procedures and measures was conducted during STS-53 in Dec. 1992. The study measures included a background questionnaire, a subjective daily logbook completed on a 24 hr. basis (to report sleep patterns, work periods, etc.), and an 8 minute performance and mood test battery administered at the beginning, middle, and end of each shift period. Seventeen Flight controllers representing the 3 Orbit shifts participated. The initial results clearly support further data collection during other STS missions to document baseline levels of alertness and performance during MOD shiftwork operations. These issues are especially pertinent for the night shift operations and the acute phase advance required for the transition of day shift personnel into the night for shuttle launch. Implementation and evaluation of the countermeasure strategies to maximize alertness and performance is planned. As STS missions extend to further extended duration orbiters, timelines and planning for 24 circadian disruption will remain highly relevant in the MOD environment.

  12. PREFACE: High Performance Computing Symposium 2011

    NASA Astrophysics Data System (ADS)

    Talon, Suzanne; Mousseau, Normand; Peslherbe, Gilles; Bertrand, François; Gauthier, Pierre; Kadem, Lyes; Moitessier, Nicolas; Rouleau, Guy; Wittig, Rod

    2012-02-01

    HPCS (High Performance Computing Symposium) is a multidisciplinary conference that focuses on research involving High Performance Computing and its application. Attended by Canadian and international experts and renowned researchers in the sciences, all areas of engineering, the applied sciences, medicine and life sciences, mathematics, the humanities and social sciences, it is Canada's pre-eminent forum for HPC. The 25th edition was held in Montréal, at the Université du Québec à Montréal, from 15-17 June and focused on HPC in Medical Science. The conference was preceded by tutorials held at Concordia University, where 56 participants learned about HPC best practices, GPU computing, parallel computing, debugging and a number of high-level languages. 274 participants from six countries attended the main conference, which involved 11 invited and 37 contributed oral presentations, 33 posters, and an exhibit hall with 16 booths from our sponsors. The work that follows is a collection of papers presented at the conference covering HPC topics ranging from computer science to bioinformatics. They are divided here into four sections: HPC in Engineering, Physics and Materials Science, HPC in Medical Science, HPC Enabling to Explore our World and New Algorithms for HPC. We would once more like to thank the participants and invited speakers, the members of the Scientific Committee, the referees who spent time reviewing the papers and our invaluable sponsors. To hear the invited talks and learn about 25 years of HPC development in Canada visit the Symposium website: http://2011.hpcs.ca/lang/en/conference/keynote-speakers/ Enjoy the excellent papers that follow, and we look forward to seeing you in Vancouver for HPCS 2012! Gilles Peslherbe Chair of the Scientific Committee Normand Mousseau Co-Chair of HPCS 2011 Suzanne Talon Chair of the Organizing Committee UQAM Sponsors The PDF also contains photographs from the conference banquet.

  13. Combining high performance simulation, data acquisition, and graphics display computers

    NASA Technical Reports Server (NTRS)

    Hickman, Robert J.

    1989-01-01

    Issues involved in the continuing development of an advanced simulation complex are discussed. This approach provides the capability to perform the majority of tests on advanced systems, non-destructively. The controlled test environments can be replicated to examine the response of the systems under test to alternative treatments of the system control design, or test the function and qualification of specific hardware. Field tests verify that the elements simulated in the laboratories are sufficient. The digital computer is hosted by a Digital Equipment Corp. MicroVAX computer with an Aptec Computer Systems Model 24 I/O computer performing the communication function. An Applied Dynamics International AD100 performs the high speed simulation computing and an Evans and Sutherland PS350 performs on-line graphics display. A Scientific Computer Systems SCS40 acts as a high performance FORTRAN program processor to support the complex, by generating numerous large files from programs coded in FORTRAN that are required for the real time processing. Four programming languages are involved in the process, FORTRAN, ADSIM, ADRIO, and STAPLE. FORTRAN is employed on the MicroVAX host to initialize and terminate the simulation runs on the system. The generation of the data files on the SCS40 also is performed with FORTRAN programs. ADSIM and ADIRO are used to program the processing elements of the AD100 and its IOCP processor. STAPLE is used to program the Aptec DIP and DIA processors.

  14. Resource estimation in high performance medical image computing.

    PubMed

    Banalagay, Rueben; Covington, Kelsie Jade; Wilkes, D M; Landman, Bennett A

    2014-10-01

    Medical imaging analysis processes often involve the concatenation of many steps (e.g., multi-stage scripts) to integrate and realize advancements from image acquisition, image processing, and computational analysis. With the dramatic increase in data size for medical imaging studies (e.g., improved resolution, higher throughput acquisition, shared databases), interesting study designs are becoming intractable or impractical on individual workstations and servers. Modern pipeline environments provide control structures to distribute computational load in high performance computing (HPC) environments. However, high performance computing environments are often shared resources, and scheduling computation across these resources necessitates higher level modeling of resource utilization. Submission of 'jobs' requires an estimate of the CPU runtime and memory usage. The resource requirements for medical image processing algorithms are difficult to predict since the requirements can vary greatly between different machines, different execution instances, and different data inputs. Poor resource estimates can lead to wasted resources in high performance environments due to incomplete executions and extended queue wait times. Hence, resource estimation is becoming a major hurdle for medical image processing algorithms to efficiently leverage high performance computing environments. Herein, we present our implementation of a resource estimation system to overcome these difficulties and ultimately provide users with the ability to more efficiently utilize high performance computing resources.

  15. Resource estimation in high performance medical image computing.

    PubMed

    Banalagay, Rueben; Covington, Kelsie Jade; Wilkes, D M; Landman, Bennett A

    2014-10-01

    Medical imaging analysis processes often involve the concatenation of many steps (e.g., multi-stage scripts) to integrate and realize advancements from image acquisition, image processing, and computational analysis. With the dramatic increase in data size for medical imaging studies (e.g., improved resolution, higher throughput acquisition, shared databases), interesting study designs are becoming intractable or impractical on individual workstations and servers. Modern pipeline environments provide control structures to distribute computational load in high performance computing (HPC) environments. However, high performance computing environments are often shared resources, and scheduling computation across these resources necessitates higher level modeling of resource utilization. Submission of 'jobs' requires an estimate of the CPU runtime and memory usage. The resource requirements for medical image processing algorithms are difficult to predict since the requirements can vary greatly between different machines, different execution instances, and different data inputs. Poor resource estimates can lead to wasted resources in high performance environments due to incomplete executions and extended queue wait times. Hence, resource estimation is becoming a major hurdle for medical image processing algorithms to efficiently leverage high performance computing environments. Herein, we present our implementation of a resource estimation system to overcome these difficulties and ultimately provide users with the ability to more efficiently utilize high performance computing resources. PMID:24906466

  16. High pressure common rail injection system modeling and control.

    PubMed

    Wang, H P; Zheng, D; Tian, Y

    2016-07-01

    In this paper modeling and common-rail pressure control of high pressure common rail injection system (HPCRIS) is presented. The proposed mathematical model of high pressure common rail injection system which contains three sub-systems: high pressure pump sub-model, common rail sub-model and injector sub-model is a relative complicated nonlinear system. The mathematical model is validated by the software Matlab and a virtual detailed simulation environment. For the considered HPCRIS, an effective model free controller which is called Extended State Observer - based intelligent Proportional Integral (ESO-based iPI) controller is designed. And this proposed method is composed mainly of the referred ESO observer, and a time delay estimation based iPI controller. Finally, to demonstrate the performances of the proposed controller, the proposed ESO-based iPI controller is compared with a conventional PID controller and ADRC. PMID:27012440

  17. High-performance commercial building facades

    SciTech Connect

    Lee, Eleanor; Selkowitz, Stephen; Bazjanac, Vladimir; Inkarojrit, Vorapat; Kohler, Christian

    2002-06-01

    This study focuses on advanced building facades that use daylighting, sun control, ventilation systems, and dynamic systems. A quick perusal of the leading architectural magazines, or a discussion in most architectural firms today will eventually lead to mention of some of the innovative new buildings that are being constructed with all-glass facades. Most of these buildings are appearing in Europe, although interestingly U.S. A/E firms often have a leading role in their design. This ''emerging technology'' of heavily glazed fagades is often associated with buildings whose design goals include energy efficiency, sustainability, and a ''green'' image. While there are a number of new books on the subject with impressive photos and drawings, there is little critical examination of the actual performance of such buildings, and a generally poor understanding as to whether they achieve their performance goals, or even what those goals might be. Even if the building ''works'' it is often dangerous to take a design solution from one climate and location and transport it to a new one without a good causal understanding of how the systems work. In addition, there is a wide range of existing and emerging glazing and fenestration technologies in use in these buildings, many of which break new ground with respect to innovative structural use of glass. It is unclear as to how well many of these designs would work as currently formulated in California locations dominated by intense sunlight and seismic events. Finally, the costs of these systems are higher than normal facades, but claims of energy and productivity savings are used to justify some of them. Once again these claims, while plausible, are largely unsupported. There have been major advances in glazing and facade technology over the past 30 years and we expect to see continued innovation and product development. It is critical in this process to be able to understand which performance goals are being met by current

  18. High-Performance Energy Applications and Systems

    SciTech Connect

    Miller, Barton

    2014-01-01

    The Paradyn project has a history of developing algorithms, techniques, and software that push the cutting edge of tool technology for high-end computing systems. Under this funding, we are working on a three-year agenda to make substantial new advances in support of new and emerging Petascale systems. The overall goal for this work is to address the steady increase in complexity of these petascale systems. Our work covers two key areas: (1) The analysis, instrumentation and control of binary programs. Work in this area falls under the general framework of the Dyninst API tool kits. (2) Infrastructure for building tools and applications at extreme scale. Work in this area falls under the general framework of the MRNet scalability framework. Note that work done under this funding is closely related to work done under a contemporaneous grant, “Foundational Tools for Petascale Computing”, SC0003922/FG02-10ER25940, UW PRJ27NU.

  19. Impact of Advance Control on Microturbine Generation System Performance

    NASA Astrophysics Data System (ADS)

    Kamil Mat Hussin, Ahmad; Zamri Che Wanik, Mohd

    2013-06-01

    Advance control employed in microturbine generation system (MTGS) is expected to improve its performance in responding to grid faults. This paper compares the effect of advance control of MTGS power conversion topology on the performance in riding through the grid faults. The analysis and investigation study through simulation shows there is no significant different on MTGS output performance even advance control is employed for its rectifier.

  20. High Thermoelectric Performance in Copper Telluride

    SciTech Connect

    He, Ying; Zhang, Tiansong; Shi, Xun; Wei, Su-Huai; Chen, Lidong

    2015-06-21

    Recently, Cu 2-δ S and Cu 2-δ Se were reported to have an ultralow thermal conductivity and high thermoelectric figure of merit zT. Thus, as a member of the copper chalcogenide group, Cu 2-δ Te is expected to possess superior zTs because Te is less ionic and heavy. However, the zT value is low in the Cu2Te sintered using spark plasma sintering, which is typically used to fabricate high-density bulk samples. In addition, the extra sintering processes may change the samples’ compositions as well as their physical properties, especially for Cu2Te, which has many stable and meta-stable phases as well as weaker ionic bonding between Cu and Te as compared with Cu2S and Cu2Se. In this study, high-density Cu2Te samples were obtained using direct annealing without a sintering process. In the absence of sintering processes, the samples’ compositions could be well controlled, leading to substantially reduced carrier concentrations that are close to the optimal value. The electrical transports were optimized, and the thermal conductivity was considerably reduced. The zT values were significantly improved—to 1.1 at 1000 K—which is nearly 100% improvement. Furthermore, this method saves substantial time and cost during the sample’s growth. The study demonstrates that Cu 2-δ X (X=S, Se and Te) is the only existing system to show high zTs in the series of compounds composed of three sequential primary group elements.

  1. High Thermoelectric Performance in Copper Telluride

    DOE PAGESBeta

    He, Ying; Zhang, Tiansong; Shi, Xun; Wei, Su-Huai; Chen, Lidong

    2015-06-21

    Recently, Cu 2-δ S and Cu 2-δ Se were reported to have an ultralow thermal conductivity and high thermoelectric figure of merit zT. Thus, as a member of the copper chalcogenide group, Cu 2-δ Te is expected to possess superior zTs because Te is less ionic and heavy. However, the zT value is low in the Cu2Te sintered using spark plasma sintering, which is typically used to fabricate high-density bulk samples. In addition, the extra sintering processes may change the samples’ compositions as well as their physical properties, especially for Cu2Te, which has many stable and meta-stable phasesmore » as well as weaker ionic bonding between Cu and Te as compared with Cu2S and Cu2Se. In this study, high-density Cu2Te samples were obtained using direct annealing without a sintering process. In the absence of sintering processes, the samples’ compositions could be well controlled, leading to substantially reduced carrier concentrations that are close to the optimal value. The electrical transports were optimized, and the thermal conductivity was considerably reduced. The zT values were significantly improved—to 1.1 at 1000 K—which is nearly 100% improvement. Furthermore, this method saves substantial time and cost during the sample’s growth. The study demonstrates that Cu 2-δ X (X=S, Se and Te) is the only existing system to show high zTs in the series of compounds composed of three sequential primary group elements.« less

  2. How to create high-performing teams.

    PubMed

    Lam, Samuel M

    2010-02-01

    This article is intended to discuss inspirational aspects on how to lead a high-performance team. Cogent topics discussed include how to hire staff through methods of "topgrading" with reference to Geoff Smart and "getting the right people on the bus" referencing Jim Collins' work. In addition, once the staff is hired, this article covers how to separate the "eagles from the ducks" and how to inspire one's staff by creating the right culture with suggestions for further reading by Don Miguel Ruiz (The four agreements) and John Maxwell (21 Irrefutable laws of leadership). In addition, Simon Sinek's concept of "Start with Why" is elaborated to help a leader know what the core element should be with any superior culture. PMID:20127598

  3. High performance stepper motors for space mechanisms

    NASA Technical Reports Server (NTRS)

    Sega, Patrick; Estevenon, Christine

    1995-01-01

    Hybrid stepper motors are very well adapted to high performance space mechanisms. They are very simple to operate and are often used for accurate positioning and for smooth rotations. In order to fulfill these requirements, the motor torque, its harmonic content, and the magnetic parasitic torque have to be properly designed. Only finite element computations can provide enough accuracy to determine the toothed structures' magnetic permeance, whose derivative function leads to the torque. It is then possible to design motors with a maximum torque capability or with the most reduced torque harmonic content (less than 3 percent of fundamental). These later motors are dedicated to applications where a microstep or a synchronous mode is selected for minimal dynamic disturbances. In every case, the capability to convert electrical power into torque is much higher than on DC brushless motors.

  4. High performance computing applications in neurobiological research

    NASA Technical Reports Server (NTRS)

    Ross, Muriel D.; Cheng, Rei; Doshay, David G.; Linton, Samuel W.; Montgomery, Kevin; Parnas, Bruce R.

    1994-01-01

    The human nervous system is a massively parallel processor of information. The vast numbers of neurons, synapses and circuits is daunting to those seeking to understand the neural basis of consciousness and intellect. Pervading obstacles are lack of knowledge of the detailed, three-dimensional (3-D) organization of even a simple neural system and the paucity of large scale, biologically relevant computer simulations. We use high performance graphics workstations and supercomputers to study the 3-D organization of gravity sensors as a prototype architecture foreshadowing more complex systems. Scaled-down simulations run on a Silicon Graphics workstation and scale-up, three-dimensional versions run on the Cray Y-MP and CM5 supercomputers.

  5. High-performance capillary electrophoresis of histones

    SciTech Connect

    Gurley, L.R.; London, J.E.; Valdez, J.G.

    1991-01-01

    A high performance capillary electrophoresis (HPCE) system has been developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in a 0.1M phosphate buffer at pH 2.5 in a 50 {mu}m {times} 35 cm coated capillary. Electrophoresis was accomplished in 9 minutes separating a whole histone preparation into its components in the following order of decreasing mobility; (MHP) H3, H1 (major variant), H1 (minor variant), (LHP) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B, (MHP) H2A (minor variant) where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase HPLC and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. 27 refs., 8 figs.

  6. Perturbing engine performance measurements to determine optimal engine control settings

    DOEpatents

    Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

    2014-12-30

    Methods and systems for optimizing a performance of a vehicle engine are provided. The method includes determining an initial value for a first engine control parameter based on one or more detected operating conditions of the vehicle engine, determining a value of an engine performance variable, and artificially perturbing the determined value of the engine performance variable. The initial value for the first engine control parameter is then adjusted based on the perturbed engine performance variable causing the engine performance variable to approach a target engine performance variable. Operation of the vehicle engine is controlled based on the adjusted initial value for the first engine control parameter. These acts are repeated until the engine performance variable approaches the target engine performance variable.

  7. Study of High Performance Coronagraphic Techniques

    NASA Technical Reports Server (NTRS)

    Crane, Phil (Technical Monitor); Tolls, Volker

    2004-01-01

    The goal of the Study of High Performance Coronagraphic Techniques project (called CoronaTech) is: 1) to verify the Labeyrie multi-step speckle reduction method and 2) to develop new techniques to manufacture soft-edge occulter masks preferably with Gaussian absorption profile. In a coronagraph, the light from a bright host star which is centered on the optical axis in the image plane is blocked by an occulter centered on the optical axis while the light from a planet passes the occulter (the planet has a certain minimal distance from the optical axis). Unfortunately, stray light originating in the telescope and subsequent optical elements is not completely blocked causing a so-called speckle pattern in the image plane of the coronagraph limiting the sensitivity of the system. The sensitivity can be increased significantly by reducing the amount of speckle light. The Labeyrie multi-step speckle reduction method implements one (or more) phase correction steps to suppress the unwanted speckle light. In each step, the stray light is rephased and then blocked with an additional occulter which affects the planet light (or other companion) only slightly. Since the suppression is still not complete, a series of steps is required in order to achieve significant suppression. The second part of the project is the development of soft-edge occulters. Simulations have shown that soft-edge occulters show better performance in coronagraphs than hard-edge occulters. In order to utilize the performance gain of soft-edge occulters. fabrication methods have to be developed to manufacture these occulters according to the specification set forth by the sensitivity requirements of the coronagraph.

  8. High-Performance Monopropellants and Catalysts Evaluated

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.

    2004-01-01

    The NASA Glenn Research Center is sponsoring efforts to develop advanced monopropellant technology. The focus has been on monopropellant formulations composed of an aqueous solution of hydroxylammonium nitrate (HAN) and a fuel component. HAN-based monopropellants do not have a toxic vapor and do not need the extraordinary procedures for storage, handling, and disposal required of hydrazine (N2H4). Generically, HAN-based monopropellants are denser and have lower freezing points than N2H4. The performance of HAN-based monopropellants depends on the selection of fuel, the HAN-to-fuel ratio, and the amount of water in the formulation. HAN-based monopropellants are not seen as a replacement for N2H4 per se, but rather as a propulsion option in their own right. For example, HAN-based monopropellants would prove beneficial to the orbit insertion of small, power-limited satellites because of this propellant's high performance (reduced system mass), high density (reduced system volume), and low freezing point (elimination of tank and line heaters). Under a Glenn-contracted effort, Aerojet Redmond Rocket Center conducted testing to provide the foundation for the development of monopropellant thrusters with an I(sub sp) goal of 250 sec. A modular, workhorse reactor (representative of a 1-lbf thruster) was used to evaluate HAN formulations with catalyst materials. Stoichiometric, oxygen-rich, and fuelrich formulations of HAN-methanol and HAN-tris(aminoethyl)amine trinitrate were tested to investigate the effects of stoichiometry on combustion behavior. Aerojet found that fuelrich formulations degrade the catalyst and reactor faster than oxygen-rich and stoichiometric formulations do. A HAN-methanol formulation with a theoretical Isp of 269 sec (designated HAN269MEO) was selected as the baseline. With a combustion efficiency of at least 93 percent demonstrated for HAN-based monopropellants, HAN269MEO will meet the I(sub sp) 250 sec goal.

  9. High performance zinc air fuel cell stack

    NASA Astrophysics Data System (ADS)

    Pei, Pucheng; Ma, Ze; Wang, Keliang; Wang, Xizhong; Song, Mancun; Xu, Huachi

    2014-03-01

    A zinc air fuel cell (ZAFC) stack with inexpensive manganese dioxide (MnO2) as the catalyst is designed, in which the circulation flowing potassium hydroxide (KOH) electrolyte carries the reaction product away and acts as a coolant. Experiments are carried out to investigate the characteristics of polarization, constant current discharge and dynamic response, as well as the factors affecting the performance and uniformity of individual cells in the stack. The results reveal that the peak power density can be as high as 435 mW cm-2 according to the area of the air cathode sheet, and the influence factors on cell performance and uniformity are cell locations, filled state of zinc pellets, contact resistance, flow rates of electrolyte and air. It is also shown that the time needed for voltages to reach steady state and that for current step-up or current step-down are both in milliseconds, indicating the ZAFC can be excellently applied to vehicles with rapid dynamic response demands.

  10. USING MULTITAIL NETWORKS IN HIGH PERFORMANCE CLUSTERS

    SciTech Connect

    S. COLL; E. FRACHTEMBERG; F. PETRINI; A. HOISIE; L. GURVITS

    2001-03-01

    Using multiple independent networks (also known as rails) is an emerging technique to overcome bandwidth limitations and enhance fault-tolerance of current high-performance clusters. We present and analyze various venues for exploiting multiple rails. Different rail access policies are presented and compared, including static and dynamic allocation schemes. An analytical lower bound on the number of networks required for static rail allocation is shown. We also present an extensive experimental comparison of the behavior of various allocation schemes in terms of bandwidth and latency. Striping messages over multiple rails can substantially reduce network latency, depending on average message size, network load and allocation scheme. The methods compared include a static rail allocation, a round-robin rail allocation, a dynamic allocation based on local knowledge, and a rail allocation that reserves both end-points of a message before sending it. The latter is shown to perform better than other methods at higher loads: up to 49% better than local-knowledge allocation and 37% better than the round-robin allocation. This allocation scheme also shows lower latency and it saturates on higher loads (for messages large enough). Most importantly, this proposed allocation scheme scales well with the number of rails and message sizes.

  11. Vortices in high-performance high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Kwok, Wai-Kwong; Welp, Ulrich; Glatz, Andreas; Koshelev, Alexei E.; Kihlstrom, Karen J.; Crabtree, George W.

    2016-11-01

    The behavior of vortex matter in high-temperature superconductors (HTS) controls the entire electromagnetic response of the material, including its current carrying capacity. Here, we review the basic concepts of vortex pinning and its application to a complex mixed pinning landscape to enhance the critical current and to reduce its anisotropy. We focus on recent scientific advances that have resulted in large enhancements of the in-field critical current in state-of-the-art second generation (2G) YBCO coated conductors and on the prospect of an isotropic, high-critical current superconductor in the iron-based superconductors. Lastly, we discuss an emerging new paradigm of critical current by design—a drive to achieve a quantitative correlation between the observed critical current density and mesoscale mixed pinning landscapes by using realistic input parameters in an innovative and powerful large-scale time dependent Ginzburg–Landau approach to simulating vortex dynamics.

  12. Continuous performance measurement in flight systems. [sequential control model

    NASA Technical Reports Server (NTRS)

    Connelly, E. M.; Sloan, N. A.; Zeskind, R. M.

    1975-01-01

    The desired response of many man machine control systems can be formulated as a solution to an optimal control synthesis problem where the cost index is given and the resulting optimal trajectories correspond to the desired trajectories of the man machine system. Optimal control synthesis provides the reference criteria and the significance of error information required for performance measurement. The synthesis procedure described provides a continuous performance measure (CPM) which is independent of the mechanism generating the control action. Therefore, the technique provides a meaningful method for online evaluation of man's control capability in terms of total man machine performance.

  13. A high performance field-reversed configuration

    SciTech Connect

    Binderbauer, M. W.; Tajima, T.; Steinhauer, L. C.; Garate, E.; Tuszewski, M.; Smirnov, A.; Gota, H.; Barnes, D.; Deng, B. H.; Thompson, M. C.; Trask, E.; Yang, X.; Putvinski, S.; Rostoker, N.; Andow, R.; Aefsky, S.; Bolte, N.; Bui, D. Q.; Ceccherini, F.; Clary, R.; and others

    2015-05-15

    Conventional field-reversed configurations (FRCs), high-beta, prolate compact toroids embedded in poloidal magnetic fields, face notable stability and confinement concerns. These can be ameliorated by various control techniques, such as introducing a significant fast ion population. Indeed, adding neutral beam injection into the FRC over the past half-decade has contributed to striking improvements in confinement and stability. Further, the addition of electrically biased plasma guns at the ends, magnetic end plugs, and advanced surface conditioning led to dramatic reductions in turbulence-driven losses and greatly improved stability. Together, these enabled the build-up of a well-confined and dominant fast-ion population. Under such conditions, highly reproducible, macroscopically stable hot FRCs (with total plasma temperature of ∼1 keV) with record lifetimes were achieved. These accomplishments point to the prospect of advanced, beam-driven FRCs as an intriguing path toward fusion reactors. This paper reviews key results and presents context for further interpretation.

  14. A high performance field-reversed configurationa)

    NASA Astrophysics Data System (ADS)

    Binderbauer, M. W.; Tajima, T.; Steinhauer, L. C.; Garate, E.; Tuszewski, M.; Schmitz, L.; Guo, H. Y.; Smirnov, A.; Gota, H.; Barnes, D.; Deng, B. H.; Thompson, M. C.; Trask, E.; Yang, X.; Putvinski, S.; Rostoker, N.; Andow, R.; Aefsky, S.; Bolte, N.; Bui, D. Q.; Ceccherini, F.; Clary, R.; Cheung, A. H.; Conroy, K. D.; Dettrick, S. A.; Douglass, J. D.; Feng, P.; Galeotti, L.; Giammanco, F.; Granstedt, E.; Gupta, D.; Gupta, S.; Ivanov, A. A.; Kinley, J. S.; Knapp, K.; Korepanov, S.; Hollins, M.; Magee, R.; Mendoza, R.; Mok, Y.; Necas, A.; Primavera, S.; Onofri, M.; Osin, D.; Rath, N.; Roche, T.; Romero, J.; Schroeder, J. H.; Sevier, L.; Sibley, A.; Song, Y.; Van Drie, A. D.; Walters, J. K.; Waggoner, W.; Yushmanov, P.; Zhai, K.

    2015-05-01

    Conventional field-reversed configurations (FRCs), high-beta, prolate compact toroids embedded in poloidal magnetic fields, face notable stability and confinement concerns. These can be ameliorated by various control techniques, such as introducing a significant fast ion population. Indeed, adding neutral beam injection into the FRC over the past half-decade has contributed to striking improvements in confinement and stability. Further, the addition of electrically biased plasma guns at the ends, magnetic end plugs, and advanced surface conditioning led to dramatic reductions in turbulence-driven losses and greatly improved stability. Together, these enabled the build-up of a well-confined and dominant fast-ion population. Under such conditions, highly reproducible, macroscopically stable hot FRCs (with total plasma temperature of ˜1 keV) with record lifetimes were achieved. These accomplishments point to the prospect of advanced, beam-driven FRCs as an intriguing path toward fusion reactors. This paper reviews key results and presents context for further interpretation.

  15. How swifts control their glide performance with morphing wings.

    PubMed

    Lentink, D; Müller, U K; Stamhuis, E J; de Kat, R; van Gestel, W; Veldhuis, L L M; Henningsson, P; Hedenström, A; Videler, J J; van Leeuwen, J L

    2007-04-26

    Gliding birds continually change the shape and size of their wings, presumably to exploit the profound effect of wing morphology on aerodynamic performance. That birds should adjust wing sweep to suit glide speed has been predicted qualitatively by analytical glide models, which extrapolated the wing's performance envelope from aerodynamic theory. Here we describe the aerodynamic and structural performance of actual swift wings, as measured in a wind tunnel, and on this basis build a semi-empirical glide model. By measuring inside and outside swifts' behavioural envelope, we show that choosing the most suitable sweep can halve sink speed or triple turning rate. Extended wings are superior for slow glides and turns; swept wings are superior for fast glides and turns. This superiority is due to better aerodynamic performance-with the exception of fast turns. Swept wings are less effective at generating lift while turning at high speeds, but can bear the extreme loads. Finally, our glide model predicts that cost-effective gliding occurs at speeds of 8-10 m s(-1), whereas agility-related figures of merit peak at 15-25 m s(-1). In fact, swifts spend the night ('roost') in flight at 8-10 m s(-1) (ref. 11), thus our model can explain this choice for a resting behaviour. Morphing not only adjusts birds' wing performance to the task at hand, but could also control the flight of future aircraft.

  16. PMSM sensorless control with separate control strategies and smooth switch from low speed to high speed.

    PubMed

    Chen, SiYi; Luo, Ying; Pi, YouGuo

    2015-09-01

    This paper proposes a smooth switching scheme with separate control strategies on low speed mode and high speed mode for permanent magnet synchronous motor (PMSM) sensorless control to improve the overall performance in full speed range. Constant voltage/frequency tuning method is used on low speed mode because the rotor position can hardly be estimated precisely at low speed. Along with the increasing speed, the control strategy can be switched to high speed mode smoothly when current and speed meet the given requirements. In this high speed mode, the current tracking with a sliding mode observer (SMO) and speed tracking with a sliding mode controller (SMC) are handled, respectively. Experimental demonstration is presented to show the desired performance in full speed range of the PMSM sensorless control using the proposed control scheme in this paper.

  17. High-Performance Beam Simulator for the LANSCE Linac

    SciTech Connect

    Pang, Xiaoying; Rybarcyk, Lawrence J.; Baily, Scott A.

    2012-05-14

    A high performance multiparticle tracking simulator is currently under development at Los Alamos. The heart of the simulator is based upon the beam dynamics simulation algorithms of the PARMILA code, but implemented in C++ on Graphics Processing Unit (GPU) hardware using NVIDIA's CUDA platform. Linac operating set points are provided to the simulator via the EPICS control system so that changes of the real time linac parameters are tracked and the simulation results updated automatically. This simulator will provide valuable insight into the beam dynamics along a linac in pseudo real-time, especially where direct measurements of the beam properties do not exist. Details regarding the approach, benefits and performance are presented.

  18. An investigation of high performance, short thrust augmenting ejectors

    NASA Astrophysics Data System (ADS)

    Yang, T.; Jiang, T.; Pitts, D. R.; Ntone, F.

    1984-12-01

    The design of air-to-air, thrust augmenting ejectors having short curved wall diffusers utilizing boundary layer control is discussed. The design is achieved by an inverse method which uses the vorticity at the diffuser inlet as a flow parameter in the analysis. Three diffusers having ejector length-to-mixing chamber diameter ratios of approximately 6:1 and mixing chamber inlet area-to-primary nozzle area ratios of 20:1 and 40:1 were designed and tested. A new high level of performance was analytically predicted and achieved experimentally. Comparisons between predicted and observed performances, velocity distributions and pressure distributions are presented.

  19. High Power Flex-Propellant Arcjet Performance

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.

    2011-01-01

    implied nearly frozen flow in the nozzle and yielded performance ranges of 800-1100 sec for hydrogen and 400-600 sec for ammonia. Inferred thrust-to-power ratios were in the range of 30-10 lbf/MWe for hydrogen and 60-20 lbf/MWe for ammonia. Successful completion of this test series represents a fundamental milestone in the progression of high power arcjet technology, and it is hoped that the results may serve as a reliable touchstone for the future development of MW-class regeneratively-cooled flex-propellant plasma rockets.

  20. High-performance computing in image registration

    NASA Astrophysics Data System (ADS)

    Zanin, Michele; Remondino, Fabio; Dalla Mura, Mauro

    2012-10-01

    Thanks to the recent technological advances, a large variety of image data is at our disposal with variable geometric, radiometric and temporal resolution. In many applications the processing of such images needs high performance computing techniques in order to deliver timely responses e.g. for rapid decisions or real-time actions. Thus, parallel or distributed computing methods, Digital Signal Processor (DSP) architectures, Graphical Processing Unit (GPU) programming and Field-Programmable Gate Array (FPGA) devices have become essential tools for the challenging issue of processing large amount of geo-data. The article focuses on the processing and registration of large datasets of terrestrial and aerial images for 3D reconstruction, diagnostic purposes and monitoring of the environment. For the image alignment procedure, sets of corresponding feature points need to be automatically extracted in order to successively compute the geometric transformation that aligns the data. The feature extraction and matching are ones of the most computationally demanding operations in the processing chain thus, a great degree of automation and speed is mandatory. The details of the implemented operations (named LARES) exploiting parallel architectures and GPU are thus presented. The innovative aspects of the implementation are (i) the effectiveness on a large variety of unorganized and complex datasets, (ii) capability to work with high-resolution images and (iii) the speed of the computations. Examples and comparisons with standard CPU processing are also reported and commented.

  1. High-performance computers for unmanned vehicles

    NASA Astrophysics Data System (ADS)

    Toms, David; Ettinger, Gil J.

    2005-10-01

    The present trend of increasing functionality onboard unmanned vehicles is made possible by rapid advances in high-performance computers (HPCs). An HPC is characterized by very high computational capability (100s of billions of operations per second) contained in lightweight, rugged, low-power packages. HPCs are critical to the processing of sensor data onboard these vehicles. Operations such as radar image formation, target tracking, target recognition, signal intelligence signature collection and analysis, electro-optic image compression, and onboard data exploitation are provided by these machines. The net effect of an HPC is to minimize communication bandwidth requirements and maximize mission flexibility. This paper focuses on new and emerging technologies in the HPC market. Emerging capabilities include new lightweight, low-power computing systems: multi-mission computing (using a common computer to support several sensors); onboard data exploitation; and large image data storage capacities. These new capabilities will enable an entirely new generation of deployed capabilities at reduced cost. New software tools and architectures available to unmanned vehicle developers will enable them to rapidly develop optimum solutions with maximum productivity and return on investment. These new technologies effectively open the trade space for unmanned vehicle designers.

  2. New high performance Si for optical devices

    NASA Astrophysics Data System (ADS)

    Tenma, T.; Matsuzaka, M.; Sako, R.; Takase, K.; Chiba, K.

    2016-05-01

    Against the backdrop of a growing demand in the areas of smart buildings, security, vehicle installation, and other applications, the market for far infrared cameras is expected to grow significantly in the future. However, since germanium (Ge) and chalcogenide glass, which have been used as the lens materials of far infrared cameras, are very expensive or highly toxic, there are some problems supporting the growing demand. We have therefore focused attention on silicon, which is inexpensive and less toxic. Although silicon has been used as a lens material of far infrared cameras, there are some problems remaining to be solved: Cz silicon is inexpensive but delivers low transmittance, and Fz silicon delivers sufficient transmittance but is expensive. We have developed New Cz silicon, which delivers high transmittance as Fz silicon does, and is inexpensive as conventional Cz silicon is. We have already started its sample work at both companies in Japan and overseas and have obtained excellent performance results. Mass production is scheduled to start in this fiscal year.

  3. High Performance Circularly Polarized Microstrip Antenna

    NASA Technical Reports Server (NTRS)

    Bondyopadhyay, Probir K. (Inventor)

    1997-01-01

    A microstrip antenna for radiating circularly polarized electromagnetic waves comprising a cluster array of at least four microstrip radiator elements, each of which is provided with dual orthogonal coplanar feeds in phase quadrature relation achieved by connection to an asymmetric T-junction power divider impedance notched at resonance. The dual fed circularly polarized reference element is positioned with its axis at a 45 deg angle with respect to the unit cell axis. The other three dual fed elements in the unit cell are positioned and fed with a coplanar feed structure with sequential rotation and phasing to enhance the axial ratio and impedance matching performance over a wide bandwidth. The centers of the radiator elements are disposed at the corners of a square with each side of a length d in the range of 0.7 to 0.9 times the free space wavelength of the antenna radiation and the radiator elements reside in a square unit cell area of sides equal to 2d and thereby permit the array to be used as a phased array antenna for electronic scanning and is realizable in a high temperature superconducting thin film material for high efficiency.

  4. Low cost, high performance far infrared microbolometer

    NASA Astrophysics Data System (ADS)

    Roer, Audun; Lapadatu, Adriana; Elfving, Anders; Kittilsland, Gjermund; Hohler, Erling

    2010-04-01

    Far infrared (FIR) is becoming more widely accepted within the automotive industry as a powerful sensor to detect Vulnerable Road Users like pedestrians and bicyclist as well as animals. The main focus of FIR system development lies in reducing the cost of their components, and this will involve optimizing all aspects of the system. Decreased pixel size, improved 3D process integration technologies and improved manufacturing yields will produce the necessary cost reduction on the sensor to enable high market penetration. The improved 3D process integration allows a higher fill factor and improved transmission/absorption properties. Together with the high Thermal Coefficient of Resistance (TCR) and low 1/f noise properties provided by monocrystalline silicon germanium SiGe thermistor material, they lead to bolometer performances beyond those of existing devices. The thermistor material is deposited and optimized on an IR wafer separated from the read-out integrated circuit (ROIC) wafer. The IR wafer is transferred to the ROIC using CMOS compatible processes and materials, utilizing a low temperature wafer bonding process. Long term vacuum sealing obtained by wafer scale packaging enables further cost reductions and improved quality. The approach allows independent optimization of ROIC and thermistor material processing and is compatible with existing MEMS-foundries, allowing fast time to market.

  5. High performance interconnection between high data rate networks

    NASA Technical Reports Server (NTRS)

    Foudriat, E. C.; Maly, K.; Overstreet, C. M.; Zhang, L.; Sun, W.

    1992-01-01

    The bridge/gateway system needed to interconnect a wide range of computer networks to support a wide range of user quality-of-service requirements is discussed. The bridge/gateway must handle a wide range of message types including synchronous and asynchronous traffic, large, bursty messages, short, self-contained messages, time critical messages, etc. It is shown that messages can be classified into three basic classes, synchronous and large and small asynchronous messages. The first two require call setup so that packet identification, buffer handling, etc. can be supported in the bridge/gateway. Identification enables resequences in packet size. The third class is for messages which do not require call setup. Resequencing hardware based to handle two types of resequencing problems is presented. The first is for a virtual parallel circuit which can scramble channel bytes. The second system is effective in handling both synchronous and asynchronous traffic between networks with highly differing packet sizes and data rates. The two other major needs for the bridge/gateway are congestion and error control. A dynamic, lossless congestion control scheme which can easily support effective error correction is presented. Results indicate that the congestion control scheme provides close to optimal capacity under congested conditions. Under conditions where error may develop due to intervening networks which are not lossless, intermediate error recovery and correction takes 1/3 less time than equivalent end-to-end error correction under similar conditions.

  6. Control Design and Performance Analysis for Autonomous Formation Flight Experimentss

    NASA Astrophysics Data System (ADS)

    Rice, Caleb Michael

    Autonomous Formation Flight is a key approach for reducing greenhouse gas emissions and managing traffic in future high density airspace. Unmanned Aerial Vehicles (UAV's) have made it possible for the physical demonstration and validation of autonomous formation flight concepts inexpensively and eliminates the flight risk to human pilots. This thesis discusses the design, implementation, and flight testing of three different formation flight control methods, Proportional Integral and Derivative (PID); Fuzzy Logic (FL); and NonLinear Dynamic Inversion (NLDI), and their respective performance behavior. Experimental results show achievable autonomous formation flight and performance quality with a pair of low-cost unmanned research fixed wing aircraft and also with a solo vertical takeoff and landing (VTOL) quadrotor.

  7. POPCORN: a Supervisory Control Simulation for Workload and Performance Research

    NASA Technical Reports Server (NTRS)

    Hart, S. G.; Battiste, V.; Lester, P. T.

    1984-01-01

    A multi-task simulation of a semi-automatic supervisory control system was developed to provide an environment in which training, operator strategy development, failure detection and resolution, levels of automation, and operator workload can be investigated. The goal was to develop a well-defined, but realistically complex, task that would lend itself to model-based analysis. The name of the task (POPCORN) reflects the visual display that depicts different task elements milling around waiting to be released and pop out to be performed. The operator's task was to complete each of 100 task elements that ere represented by different symbols, by selecting a target task and entering the desired a command. The simulated automatic system then completed the selected function automatically. Highly significant differences in performance, strategy, and rated workload were found as a function of all experimental manipulations (except reward/penalty).

  8. A secure communications infrastructure for high-performance distributed computing

    SciTech Connect

    Foster, I.; Koenig, G.; Tuecke, S.

    1997-08-01

    Applications that use high-speed networks to connect geographically distributed supercomputers, databases, and scientific instruments may operate over open networks and access valuable resources. Hence, they can require mechanisms for ensuring integrity and confidentially of communications and for authenticating both users and resources. Security solutions developed for traditional client-server applications do not provide direct support for the program structures, programming tools, and performance requirements encountered in these applications. The authors address these requirements via a security-enhanced version of the Nexus communication library; which they use to provide secure versions of parallel libraries and languages, including the Message Passing Interface. These tools permit a fine degree of control over what, where, and when security mechanisms are applied. In particular, a single application can mix secure and nonsecure communication, allowing the programmer to make fine-grained security/performance tradeoffs. The authors present performance results that quantify the performance of their infrastructure.

  9. An optimal performance control scheme for a 3D crane

    NASA Astrophysics Data System (ADS)

    Maghsoudi, Mohammad Javad; Mohamed, Z.; Husain, A. R.; Tokhi, M. O.

    2016-01-01

    This paper presents an optimal performance control scheme for control of a three dimensional (3D) crane system including a Zero Vibration shaper which considers two control objectives concurrently. The control objectives are fast and accurate positioning of a trolley and minimum sway of a payload. A complete mathematical model of a lab-scaled 3D crane is simulated in Simulink. With a specific cost function the proposed controller is designed to cater both control objectives similar to a skilled operator. Simulation and experimental studies on a 3D crane show that the proposed controller has better performance as compared to a sequentially tuned PID-PID anti swing controller. The controller provides better position response with satisfactory payload sway in both rail and trolley responses. Experiments with different payloads and cable lengths show that the proposed controller is robust to changes in payload with satisfactory responses.

  10. Enhanced control performance and application to fuel cell systems

    NASA Astrophysics Data System (ADS)

    Shishodia, Vikram

    The inverted-pendulum virtual control lab, a simulation environment for teaching advanced concepts of process control, is designed using the LabVIEW software tool. Significant advantages of using this simulation tool for pedagogical purposes include avoiding the potential issue of schedule conflicts for securing equipment-access time in a physical laboratory and providing a learning resource that becomes accessible to students located in remote geographical places. A set of tuning relationships are proposed for standard proportional-integral controllers and proportional double-integral controllers for the purpose of tracking the slope of a ramp trajectory. Three different performance metrics are investigated to serve as the criteria for optimality, and a numerical optimization procedure is used to minimize each metric over 20,000 different plants. The proportional integral controller with tuning parameters selected to optimize value of the integral of the time-weighted absolute error is recommended for tracking the slope of a ramp trajectory. A generalized predictive control (GPC) strategy is proposed for a fuel cell system, where the controller incorporates a measured disturbance in the control design. The control objective is to maintain oxygen excess ratio at a prescribed constant value. The performance of the GPC control design is compared with that of the controllers proposed in literature for various scenarios including model uncertainty. The GPC controller has zero offset when the performance variable is measured and performs better than competing designs offered in the literature. The GPC controller is also robust with respect to model uncertainty. A battery of observers with a switching strategy is proposed for estimating the value of the performance variable when it is not measured. The GPC controller with a battery of observers has no offset demonstrating better performance than analogous designs proposed in literature. However, the control performance

  11. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1995-05-09

    A high performance capacitor is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The notepad capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  12. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1996-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  13. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1995-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  14. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1996-01-23

    A high performance capacitor is described which is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200--300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The ``notepad`` capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  15. Electrostatic precipitator control for high resistivity particulate

    SciTech Connect

    Bibbo, P.P.; Hankins, F.E.; Jakoplic, R.

    1982-01-19

    A method and apparatus are described for optimizing the operating efficiency of an electrostatic precipitator based on controlling the average input power of the precipitator electrodes in response to control signals derived by sensing changes in specific instantaneous peak voltages associated with the average electrode voltages. The method is particularly well suited for electrostatic precipitators processing high resistivity fly ash and exhibiting an inflection region in its kvmin electrode voltage characteristic. The apparatus is organized to serve as a stand alone control system, or as an adjunct to existing electrostatic precipitator control systems.

  16. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  17. High performance constructed wetlands for cold climates.

    PubMed

    Jenssen, Petter D; Maehlum, Trend; Krogstad, Tore; Vråle, Lasse

    2005-01-01

    In 1991, the first subsurface flow constructed wetland for treatment of domestic wastewater was built in Norway. Today, this method is rapidly becoming a popular method for wastewater treatment in rural Norway. This is due to excellent performance even during winter and low maintenance. The systems can be constructed regardless of site conditions. The Norwegian concept for small constructed wetlands is based on the use of a septic tank followed by an aerobic vertical down-flow biofilter succeeded by a subsurface horizontal-flow constructed wetland. The aerobic biofilter, prior to the subsurface flow stage, is essential to remove BOD and achieve nitrification in a climate where the plants are dormant during the cold season. When designed according to present guidelines a consistent P-removal of > 90% can be expected for 15 years using natural iron or calcium rich sand or a new manufactured lightweight aggregate with P-sorption capacities, which exceeds most natural media. When the media is saturated with P it can be used as soil conditioner and P-fertilizer. Nitrogen removal in the range of 40-60% is achieved. Removal of indicator bacteria is high and < 1000 thermotolerant coliforms/100 ml is normally achieved.

  18. High performance vapour-cell frequency standards

    NASA Astrophysics Data System (ADS)

    Gharavipour, M.; Affolderbach, C.; Kang, S.; Bandi, T.; Gruet, F.; Pellaton, M.; Mileti, G.

    2016-06-01

    We report our investigations on a compact high-performance rubidium (Rb) vapour-cell clock based on microwave-optical double-resonance (DR). These studies are done in both DR continuous-wave (CW) and Ramsey schemes using the same Physics Package (PP), with the same Rb vapour cell and a magnetron-type cavity with only 45 cm3 external volume. In the CW-DR scheme, we demonstrate a DR signal with a contrast of 26% and a linewidth of 334 Hz; in Ramsey-DR mode Ramsey signals with higher contrast up to 35% and a linewidth of 160 Hz have been demonstrated. Short-term stabilities of 1.4×10-13 τ-1/2 and 2.4×10-13 τ-1/2 are measured for CW-DR and Ramsey-DR schemes, respectively. In the Ramsey-DR operation, thanks to the separation of light and microwave interactions in time, the light-shift effect has been suppressed which allows improving the long-term clock stability as compared to CW-DR operation. Implementations in miniature atomic clocks are considered.

  19. Compact high performance spectrometers using computational imaging

    NASA Astrophysics Data System (ADS)

    Morton, Kenneth; Weisberg, Arel

    2016-05-01

    Compressive sensing technology can theoretically be used to develop low cost compact spectrometers with the performance of larger and more expensive systems. Indeed, compressive sensing for spectroscopic systems has been previously demonstrated using coded aperture techniques, wherein a mask is placed between the grating and a charge coupled device (CCD) and multiple measurements are collected with different masks. Although proven effective for some spectroscopic sensing paradigms (e.g. Raman), this approach requires that the signal being measured is static between shots (low noise and minimal signal fluctuation). Many spectroscopic techniques applicable to remote sensing are inherently noisy and thus coded aperture compressed sensing will likely not be effective. This work explores an alternative approach to compressed sensing that allows for reconstruction of a high resolution spectrum in sensing paradigms featuring significant signal fluctuations between measurements. This is accomplished through relatively minor changes to the spectrometer hardware together with custom super-resolution algorithms. Current results indicate that a potential overall reduction in CCD size of up to a factor of 4 can be attained without a loss of resolution. This reduction can result in significant improvements in cost, size, and weight of spectrometers incorporating the technology.

  20. An integrated high performance Fastbus slave interface

    SciTech Connect

    Christiansen, J.; Ljuslin, C. )

    1993-08-01

    A high performance CMOS Fastbus slave interface ASIC (Application Specific Integrated Circuit) supporting all addressing and data transfer modes defined in the IEEE 960 - 1986 standard is presented. The FAstbus Slave Integrated Circuit (FASIC) is an interface between the asynchronous Fastbus and a clock synchronous processor/memory bus. It can work stand-alone or together with a 32 bit microprocessor. The FASIC is a programmable device enabling its direct use in many different applications. A set of programmable address mapping windows can map Fastbus addresses to convenient memory addresses and at the same time act as address decoding logic. Data rates of 100 MBytes/sec to Fastbus can be obtained using an internal FIFO in the FASIC to buffer data between the two buses during block transfers. Message passing from Fastbus to a microprocessor on the slave module is supported. A compact (70 mm x 170 mm) Fastbus slave piggy back sub-card interface including level conversion between ECL and TTL signal levels has been implemented using surface mount components and the 208 pin FASIC chip.

  1. Comparison between the performance of two classes of fuzzy controllers

    NASA Technical Reports Server (NTRS)

    Janabi, T. H.; Sultan, L. H.

    1992-01-01

    This paper presents an application comparison between two classes of fuzzy controllers: the Clearness Transformation Fuzzy Controller (CTFC) and the CRI-based Fuzzy Controller. The comparison is performed by studying the application of the controllers to simulation examples of nonlinear systems. The CTFC is a new approach for the organization of fuzzy controllers based on a cognitive model of parameter driven control, the notion of fuzzy patterns to represent fuzzy knowledge and the Clearness Transformation Rule of Inference (CTRI) for approximate reasoning. The approach facilitates the implementation of the basic modules of the controller: the fuzzifier, defuzzifier, and the control protocol in a rule-based architecture. The CTRI scheme for approximate reasoning does not require the formation of fuzzy relation matrices yielding improved performance in comparison with the traditional organization of fuzzy controllers.

  2. Dynamic Curvature Steering Control for Autonomous Vehicle: Performance Analysis

    NASA Astrophysics Data System (ADS)

    Aizzat Zakaria, Muhammad; Zamzuri, Hairi; Amri Mazlan, Saiful

    2016-02-01

    This paper discusses the design of dynamic curvature steering control for autonomous vehicle. The lateral control and longitudinal control are discussed in this paper. The controller is designed based on the dynamic curvature calculation to estimate the path condition and modify the vehicle speed and steering wheel angle accordingly. In this paper, the simulation results are presented to show the capability of the controller to track the reference path. The controller is able to predict the path and modify the vehicle speed to suit the path condition. The effectiveness of the controller is shown in this paper whereby identical performance is achieved with the benchmark but with extra curvature adaptation capabilites.

  3. Control system for high power laser drilling workover and completion unit

    DOEpatents

    Zediker, Mark S; Makki, Siamak; Faircloth, Brian O; DeWitt, Ronald A; Allen, Erik C; Underwood, Lance D

    2015-05-12

    A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

  4. Decoupling congestion control and error control mechanisms in TCP and evaluating their performance over broadband satellite networks

    NASA Astrophysics Data System (ADS)

    Wang, Lina; Gu, Xuemai

    2004-04-01

    In this paper, we propose a novel method to better evaluate the performance of TCP over broadband satellite networks. We decouple the most crucial parts of TCP that impact its performance in broadband satellite environments, namely congestion control and error control mechanisms. And then we re-design these two function blocks and make them become two individual parts. With these re-designed modules, we have investigated the interactions between various currently existing TCP congestion control and error control schemes, as well as their impact on TCP performance over a geostationary broadband satellite link with long propagation delay and high bit error rate. Simulation results have shown that some combinations of different congestion control and error control mechanisms can waste satellite link bandwidth with large numbers of retransmission packets and unnecessary retransmission packets. And the modified TCP NewReno implementation can avoid high amount of retransmissions and unnecessary retransmissions.

  5. Experience with high-performance PACS

    NASA Astrophysics Data System (ADS)

    Wilson, Dennis L.; Goldburgh, Mitchell M.; Head, Calvin

    1997-05-01

    Lockheed Martin (Loral) has installed PACS with associated teleradiology in several tens of hospitals. The PACS that have been installed have been the basis for a shift to filmless radiology in many of the hospitals. the basic structure for the PACS and the teleradiology that is being used is outlined. The way that the PACS are being used in the hospitals is instructive. The three most used areas for radiology in the hospital are the wards including the ICU wards, the emergency room, and the orthopedics clinic. The examinations are mostly CR images with 20 percent to 30 percent of the examinations being CT, MR, and ultrasound exams. The PACS are being used to realize improved productivity for radiology and for the clinicians. For radiology the same staff is being used for 30 to 50 percent more workload. For the clinicians 10 to 20 percent of their time is being saved in dealing with radiology images. The improved productivity stems from the high performance of the PACS that has been designed and installed. Images are available on any workstation in the hospital within less than two seconds, even during the busiest hour of the day. The examination management functions to restrict the attention of any one user to the examinations that are of interest. The examination management organizes the workflow through the radiology department and the hospital, improving the service of the radiology department by reducing the time until the information from a radiology examination is available. The remaining weak link in the PACS system is transcription. The examination can be acquired, read, an the report dictated in much less than ten minutes. The transcription of the dictated reports can take from a few hours to a few days. The addition of automatic transcription services will remove this weak link.

  6. Experimental Evaluation of High Performance Integrated Heat Pump

    SciTech Connect

    Miller, William A; Berry, Robert; Durfee, Neal; Baxter, Van D

    2016-01-01

    Integrated heat pump (IHP) technology provides significant potential for energy savings and comfort improvement for residential buildings. In this study, we evaluate the performance of a high performance IHP that provides space heating, cooling, and water heating services. Experiments were conducted according to the ASHRAE Standard 206-2013 where 24 test conditions were identified in order to evaluate the IHP performance indices based on the airside performance. Empirical curve fits of the unit s compressor maps are used in conjunction with saturated condensing and evaporating refrigerant conditions to deduce the refrigerant mass flowrate, which, in turn was used to evaluate the refrigerant side performance as a check on the airside performance. Heat pump (compressor, fans, and controls) and water pump power were measured separately per requirements of Standard 206. The system was charged per the system manufacturer s specifications. System test results are presented for each operating mode. The overall IHP performance metrics are determined from the test results per the Standard 206 calculation procedures.

  7. High Performance Input/Output Systems for High Performance Computing and Four-Dimensional Data Assimilation

    NASA Technical Reports Server (NTRS)

    Fox, Geoffrey C.; Ou, Chao-Wei

    1997-01-01

    The approach of this task was to apply leading parallel computing research to a number of existing techniques for assimilation, and extract parameters indicating where and how input/output limits computational performance. The following was used for detailed knowledge of the application problems: 1. Developing a parallel input/output system specifically for this application 2. Extracting the important input/output characteristics of data assimilation problems; and 3. Building these characteristics s parameters into our runtime library (Fortran D/High Performance Fortran) for parallel input/output support.

  8. High performance network and channel-based storage

    NASA Technical Reports Server (NTRS)

    Katz, Randy H.

    1991-01-01

    In the traditional mainframe-centered view of a computer system, storage devices are coupled to the system through complex hardware subsystems called input/output (I/O) channels. With the dramatic shift towards workstation-based computing, and its associated client/server model of computation, storage facilities are now found attached to file servers and distributed throughout the network. We discuss the underlying technology trends that are leading to high performance network-based storage, namely advances in networks, storage devices, and I/O controller and server architectures. We review several commercial systems and research prototypes that are leading to a new approach to high performance computing based on network-attached storage.

  9. Storage Area Networks and The High Performance Storage System

    SciTech Connect

    Hulen, H; Graf, O; Fitzgerald, K; Watson, R W

    2002-03-04

    The High Performance Storage System (HPSS) is a mature Hierarchical Storage Management (HSM) system that was developed around a network-centered architecture, with client access to storage provided through third-party controls. Because of this design, HPSS is able to leverage today's Storage Area Network (SAN) infrastructures to provide cost effective, large-scale storage systems and high performance global file access for clients. Key attributes of SAN file systems are found in HPSS today, and more complete SAN file system capabilities are being added. This paper traces the HPSS storage network architecture from the original implementation using HIPPI and IPI-3 technology, through today's local area network (LAN) capabilities, and to SAN file system capabilities now in development. At each stage, HPSS capabilities are compared with capabilities generally accepted today as characteristic of storage area networks and SAN file systems.

  10. Magnetic Bearing Controller Improvements for High Speed Flywheel System

    NASA Technical Reports Server (NTRS)

    Dever, Timothy P.; Brown, Gerald V.; Jansen, Ralph H.; Kascak, Peter E.; Provenza, Andrew J.

    2003-01-01

    A magnetic bearing control system for a high-speed flywheel system is described. The flywheel utilizes a five axis active magnetic bearing system, using eddy current sensors for position feedback to the bearing controller. Magnetic bearing controller features designed to improve flywheel operation and testing are described. Operational improvements include feed forward control to compensate for rotor imbalance, moving notch filtering to compensate for synchronous and harmonic rotational noise, and fixed notching to prevent rotor bending mode excitation. Testing improvements include adding safe gain, bearing current hold, bearing current zero, and excitation input features. Performance and testing improvements provided by these features are measured and discussed.

  11. Preliminary supersonic flight test evaluation of performance seeking control

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Gilyard, Glenn B.

    1993-01-01

    Digital flight and engine control, powerful onboard computers, and sophisticated controls techniques may improve aircraft performance by maximizing fuel efficiency, maximizing thrust, and extending engine life. An adaptive performance seeking control system for optimizing the quasi-steady state performance of an F-15 aircraft was developed and flight tested. This system has three optimization modes: minimum fuel, maximum thrust, and minimum fan turbine inlet temperature. Tests of the minimum fuel and fan turbine inlet temperature modes were performed at a constant thrust. Supersonic single-engine flight tests of the three modes were conducted using varied after burning power settings. At supersonic conditions, the performance seeking control law optimizes the integrated airframe, inlet, and engine. At subsonic conditions, only the engine is optimized. Supersonic flight tests showed improvements in thrust of 9 percent, increases in fuel savings of 8 percent, and reductions of up to 85 deg R in turbine temperatures for all three modes. The supersonic performance seeking control structure is described and preliminary results of supersonic performance seeking control tests are given. These findings have implications for improving performance of civilian and military aircraft.

  12. High performance MEMS micro-gyroscope

    NASA Technical Reports Server (NTRS)

    Bae, S. Y.; Hayworth, K. J.; Yee, K. Y.; Shcheglov, K.; Challoner, A. D.; Wiberg, D. V.

    2002-01-01

    This paper reports on JPL's on-going research into MEMS gyroscopes. This paper will describe the gyroscope's fabrication-methods, a new 8-electrode layout developed to improve performance, and performance statistics of a batch of six gyroscopes recently rate tested.

  13. Maintaining safety and high performance on shiftwork

    NASA Technical Reports Server (NTRS)

    Monk, T. H.; Folkard, S.; Wedderburn, A. I.

    1996-01-01

    This review of the shiftwork area focuses on aspects of safety and productivity. It discusses the situations in which shiftworker performance is critical, the types of problem that can develop and the reasons why shiftworker performance can be impaired. The review ends with a discnssion of the various advantages and disadvantages of several shift rotation systems, and of other possible solutions to the problem.

  14. OVERALL CONTROL SYSTEM FOR HIGH FLUX PILE

    DOEpatents

    Newson, H.W.; Durham, N.C.; Wigner, E.P.; Princeton, N.J.; Epler, E.P.

    1961-05-23

    A control system is given for a high fiux reactor incorporating an anti- scram control feature whereby a neutron absorbing control rod acts as a fine adjustment while a neutron absorbing shim rod, actuated upon a command received from reactor period and level signals, has substantially greater effect on the neutron level and is moved prior to scram conditions to alter the reactor activity before a scram condition is created. Thus the probability that a scram will have to be initiated is substantially decreased.

  15. Human manual control performance in hyper-gravity.

    PubMed

    Clark, Torin K; Newman, Michael C; Merfeld, Daniel M; Oman, Charles M; Young, Laurence R

    2015-05-01

    Hyper-gravity provides a unique environment to study how misperceptions impact control of orientation relative to gravity. Previous studies have found that static and dynamic roll tilts are perceptually overestimated in hyper-gravity. The current investigation quantifies how this influences control of orientation. We utilized a long-radius centrifuge to study manual control performance in hyper-gravity. In the dark, subjects were tasked with nulling out a pseudo-random roll disturbance on the cab of the centrifuge using a rotational hand controller to command their roll rate in order to remain perceptually upright. The task was performed in 1, 1.5, and 2 G's of net gravito-inertial acceleration. Initial performance, in terms of root-mean-square deviation from upright, degraded in hyper-gravity relative to 1 G performance levels. In 1.5 G, initial performance degraded by 26 % and in 2 G, by 45 %. With practice, however, performance in hyper-gravity improved to near the 1 G performance level over several minutes. Finally, pre-exposure to one hyper-gravity level reduced initial performance decrements in a different, novel, hyper-gravity level. Perceptual overestimation of roll tilts in hyper-gravity leads to manual control performance errors, which are reduced both with practice and with pre-exposure to alternate hyper-gravity stimuli.

  16. High Stability Engine Control (HISTEC) Flight Test Results

    NASA Technical Reports Server (NTRS)

    Southwick, Robert D.; Gallops, George W.; Kerr, Laura J.; Kielb, Robert P.; Welsh, Mark G.; DeLaat, John C.; Orme, John S.

    1998-01-01

    The High Stability Engine Control (HISTEC) Program, managed and funded by the NASA Lewis Research Center, is a cooperative effort between NASA and Pratt & Whitney (P&W). The program objective is to develop and flight demonstrate an advanced high stability integrated engine control system that uses real-time, measurement-based estimation of inlet pressure distortion to enhance engine stability. Flight testing was performed using the NASA Advanced Controls Technologies for Integrated Vehicles (ACTIVE) F-15 aircraft at the NASA Dryden Flight Research Center. The flight test configuration, details of the research objectives, and the flight test matrix to achieve those objectives are presented. Flight test results are discussed that show the design approach can accurately estimate distortion and perform real-time control actions for engine accommodation.

  17. HIGH STRENGTH CONTROL RODS FOR NEUTRONIC REACTORS

    DOEpatents

    Lustman, B.; Losco, E.F.; Cohen, I.

    1961-07-11

    Nuclear reactor control rods comprised of highly compressed and sintered finely divided metal alloy panticles and fine metal oxide panticles substantially uniformly distributed theretbrough are described. The metal alloy consists essentially of silver, indium, cadmium, tin, and aluminum, the amount of each being present in centain percentages by weight. The oxide particles are metal oxides of the metal alloy composition, the amount of oxygen being present in certain percentages by weight and all the oxygen present being substantially in the form of metal oxide. This control rod is characterized by its high strength and resistance to creep at elevated temperatures.

  18. NEW HIGHER PERFORMANCE LOW COST SELECTIVE SOLAR RADIATION CONTROL COATINGS

    SciTech Connect

    Timothy Ellison; Buddie Dotter; David Tsu

    2003-10-28

    Energy Conversion Devices, Inc., ECD, has developed a new high-speed low-cost process for depositing high quality dielectric optical coatings--Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD). This process can deposit SiO{sub x} about 10 times faster than the state-of-the-art conventional technology, magnetron sputtering, at about 1/10th the cost. This process is also being optimized for depositing higher refractive index materials such as Si{sub 3}N{sub 4} and TiO{sub 2}. In this program ECD, in collaboration with Southwall Technologies, Inc. (STI), demonstrated that this process can be used to fabricate high performance low cost Selective Solar Radiation Control (SSRC) films for use in the automotive industry. These coatings were produced on thin (2 mil thick) PET substrates in ECD's pilot roll-to-roll pilot MPECVD deposition machine. Such film can be laminated with PVB in a vehicle's windows. This process can also be used to deposit the films directly onto the glass. Such highly selective films, with a visible transmission (T{sub vis}) of > 70% and a shading coefficient of < 60% can significantly reduce the heat entering a car from solar radiation. Consequently, passenger comfort is increased and the energy needed to operate air conditioning (a/c) systems is reduced; consequently smaller a/c systems can be employed resulting in improved vehicle fuel efficiency.

  19. Performance and Controllability of Pulsed Ion Beam Ablation Propulsion

    SciTech Connect

    Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi

    2006-05-02

    We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

  20. High Performance Diesel Fueled Cabin Heater

    SciTech Connect

    Butcher, Tom

    2001-08-05

    Recent DOE-OHVT studies show that diesel emissions and fuel consumption can be greatly reduced at truck stops by switching from engine idle to auxiliary-fired heaters. Brookhaven National Laboratory (BNL) has studied high performance diesel burner designs that address the shortcomings of current low fire-rate burners. Initial test results suggest a real opportunity for the development of a truly advanced truck heating system. The BNL approach is to use a low pressure, air-atomized burner derived form burner designs used commonly in gas turbine combustors. This paper reviews the design and test results of the BNL diesel fueled cabin heater. The burner design is covered by U.S. Patent 6,102,687 and was issued to U.S. DOE on August 15, 2000.The development of several novel oil burner applications based on low-pressure air atomization is described. The atomizer used is a pre-filming, air blast nozzle of the type commonly used in gas turbine combustion. The air pressure used can b e as low as 1300 Pa and such pressure can be easily achieved with a fan. Advantages over conventional, pressure-atomized nozzles include ability to operate at low input rates without very small passages and much lower fuel pressure requirements. At very low firing rates the small passage sizes in pressure swirl nozzles lead to poor reliability and this factor has practically constrained these burners to firing rates over 14 kW. Air atomization can be used very effectively at low firing rates to overcome this concern. However, many air atomizer designs require pressures that can be achieved only with a compressor, greatly complicating the burner package and increasing cost. The work described in this paper has been aimed at the practical adaptation of low-pressure air atomization to low input oil burners. The objective of this work is the development of burners that can achieve the benefits of air atomization with air pressures practically achievable with a simple burner fan.

  1. Morphology engineering of high performance binary oxide electrodes.

    PubMed

    Chen, Kunfeng; Sun, Congting; Xue, Dongfeng

    2015-01-14

    Advances in materials have preceded almost every major technological leap since the beginning of civilization. On the nanoscale and microscale, mastery over the morphology, size, and structure of a material enables control of its properties and enhancement of its usefulness for a given application, such as energy storage. In this review paper, our aim is to present a review of morphology engineering of high performance oxide electrode materials for electrochemical energy storage. We begin with the chemical bonding theory of single crystal growth to direct the growth of morphology-controllable materials. We then focus on the growth of various morphologies of binary oxides and their electrochemical performances for lithium ion batteries and supercapacitors. The morphology-performance relationships are elaborated by selecting examples in which there is already reasonable understanding for this relationship. Based on these comprehensive analyses, we proposed colloidal supercapacitor systems beyond morphology control on the basis of system- and ion-level design. We conclude this article with personal perspectives on the directions toward which future research in this field might take. PMID:25406718

  2. Jules Horowitz Reactor: a high performance material testing reactor

    NASA Astrophysics Data System (ADS)

    Iracane, Daniel; Chaix, Pascal; Alamo, Ana

    2008-04-01

    The physical modelling of materials' behaviour under severe conditions is an indispensable element for developing future fission and fusion systems: screening, design, optimisation, processing, licensing, and lifetime assessment of a new generation of structure materials and fuels, which will withstand high fast neutron flux at high in-service temperatures with the production of elements like helium and hydrogen. JANNUS and other analytical experimental tools are developed for this objective. However, a purely analytical approach is not sufficient: there is a need for flexible experiments integrating higher scales and coupled phenomena and offering high quality measurements; these experiments are performed in material testing reactors (MTR). Moreover, complementary representative experiments are usually performed in prototypes or dedicated facilities such as IFMIF for fusion. Only such a consistent set of tools operating on a wide range of scales, can provide an actual prediction capability. A program such as the development of silicon carbide composites (600-1200 °C) illustrates this multiscale strategy. Facing the long term needs of experimental irradiations and the ageing of present MTRs, it was thought necessary to implement a new generation high performance MTR in Europe for supporting existing and future nuclear reactors. The Jules Horowitz Reactor (JHR) project copes with this context. It is funded by an international consortium and will start operation in 2014. JHR will provide improved performances such as high neutron flux ( 10 n/cm/s above 0.1 MeV) in representative environments (coolant, pressure, temperature) with online monitoring of experimental parameters (including stress and strain control). Experimental devices designing, such as high dpa and small thermal gradients experiments, is now a key objective requiring a broad collaboration to put together present scientific state of art, end-users requirements and advanced instrumentation. To cite this

  3. FRAMEWORK AND APPLICATION FOR MODELING CONTROL ROOM CREW PERFORMANCE AT NUCLEAR POWER PLANTS

    SciTech Connect

    Ronald L Boring; David I Gertman; Tuan Q Tran; Brian F Gore

    2008-09-01

    This paper summarizes an emerging project regarding the utilization of high-fidelity MIDAS simulations for visualizing and modeling control room crew performance at nuclear power plants. The key envisioned uses for MIDAS-based control room simulations are: (i) the estimation of human error associated with advanced control room equipment and configurations, (ii) the investigative determination of contributory cognitive factors for risk significant scenarios involving control room operating crews, and (iii) the certification of reduced staffing levels in advanced control rooms. It is proposed that MIDAS serves as a key component for the effective modeling of cognition, elements of situation awareness, and risk associated with human performance in next generation control rooms.

  4. Bedford Farmhouse High Performance Retrofit Prototype

    SciTech Connect

    2010-04-26

    In this case study, Building Science Corporation partnered with Habitat for Humanity of Greater Lowell on a retrofit of a mid-19th century farmhouse into affordable housing meeting Building America performance standards.

  5. Use corporate culture to trigger high performance.

    PubMed

    Bettinger, C

    1989-01-01

    The challenge is to manage the organization's culture so that you can tap the company's strengths to achieve superior performance and identify its weaknesses in time to overcome them before they cause serious damage.

  6. High Reliability Engine Control Demonstrated for Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Guo, Ten-Huei

    1999-01-01

    For a dual redundant-control system, which is typical for short-haul aircraft, if a failure is detected in a control sensor, the engine control is transferred to a safety mode and an advisory is issued for immediate maintenance action to replace the failed sensor. The safety mode typically results in severely degraded engine performance. The goal of the High Reliability Engine Control (HREC) program was to demonstrate that the neural-network-based sensor validation technology can safely operate an engine by using the nominal closed-loop control during and after sensor failures. With this technology, engine performance could be maintained, and the sensor could be replaced as a conveniently scheduled maintenance action.

  7. 75 FR 35092 - Submission for Review: Performance Measurement Surveys, OMB Control No. 3206-NEW

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-21

    ... MANAGEMENT Submission for Review: Performance Measurement Surveys, OMB Control No. 3206-NEW AGENCY: U.S... on a new information collection request (ICR) 3206-NEW, Performance Measurement Surveys. As required... high quality and diverse workforce. Performance measurement surveys are valuable tools to...

  8. High Performance Electrolyzers for Hybrid Thermochemical Cycles

    SciTech Connect

    Dr. John W. Weidner

    2009-05-10

    Extensive electrolyzer testing was performed at the University of South Carolina (USC). Emphasis was given to understanding water transport under various operating (i.e., temperature, membrane pressure differential and current density) and design (i.e., membrane thickness) conditions when it became apparent that water transport plays a deciding role in cell voltage. A mathematical model was developed to further understand the mechanisms of water and SO2 transport, and to predict the effect of operating and design parameters on electrolyzer performance.

  9. 1998 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    McMillin, S. Naomi (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1998 Aerodynamic Performance Technical Review on February 9-13, in Los Angeles, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High-Lift, and Flight Controls. The review objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientists and engineers working HSCT aerodynamics. In particular, single- and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program.

  10. 1999 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    Hahne, David E. (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1999 Aerodynamic Performance Technical Review on February 8-12, 1999 in Anaheim, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in the areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High Lift, and Flight Controls. The review objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among die scientists and engineers working on HSCT aerodynamics. In particular, single and midpoint optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented, along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program. This Volume 2/Part 2 publication covers the tools and methods development session.

  11. Secrets of high-performance image display

    NASA Astrophysics Data System (ADS)

    Desormeaux, David A.

    1996-04-01

    Medical imaging companies have traditionally supplied the industry with image visualization solutions based on their own custom hardware designs. Today, more and more systems are being deployed using only off-the-shelf workstations. Two major factors are driving this change. First, workstations are delivering the functionality and performance required to replace custom hardware for an ever increasing subset of visualization techniques, while continuing to come down in cost. Second, cost pressures are forcing medical imaging companies to OEM the hardware platform and focus on what they do best -- delivering solutions to health care providers. This industry shift is challenging the workstation vendors to deliver the maximum inherent performance in their computer systems to medical imaging applications without locking the application into a specific vendor's hardware. Since extracting the maximum performance from a workstation is not always intuitively obvious and often requires vendor-specific tricks, the best way to deliver performance to an application is through an application programmer's interface (API). The Hewlett-Packard Image Visualization Library (HP-IVL) is such an API. It transparently delivers the maximum possible imaging performance on Hewlett-Packard workstations, while allowing significant portability between platforms. This paper describes the performance tricks and trade-offs made in the software implementation of HP's Image Visualization Library and how the HP Image Visualization Accelerator (HP-IVX) fits into the overall architecture.

  12. Thermal Performance Analysis of a High-Mass Residential Building

    SciTech Connect

    Smith, M.W.; Torcellini, P.A., Hayter, S.J.; Judkoff, R.

    2001-01-30

    Minimizing energy consumption in residential buildings using passive solar strategies almost always calls for the efficient use of massive building materials combined with solar gain control and adequate insulation. Using computerized simulation tools to understand the interactions among all the elements facilitates designing low-energy houses. Finally, the design team must feel confident that these tools are providing realistic results. The design team for the residential building described in this paper relied on computerized design tools to determine building envelope features that would maximize the energy performance [1]. Orientation, overhang dimensions, insulation amounts, window characteristics and other strategies were analyzed to optimize performance in the Pueblo, Colorado, climate. After construction, the actual performance of the house was monitored using both short-term and long-term monitoring approaches to verify the simulation results and document performance. Calibrated computer simulations showed that this house consumes 56% less energy than would a similar theoretical house constructed to meet the minimum residential energy code requirements. This paper discusses this high-mass house and compares the expected energy performance, based on the computer simulations, versus actual energy performance.

  13. High-Flux, High Performance H2O2 Catalyst Bed for ISTAR

    NASA Technical Reports Server (NTRS)

    Ponzo, J.

    2005-01-01

    On NASA's ISTAR RBCC program packaging and performance requirements exceeded traditional H2O2 catalyst bed capabilities. Aerojet refined a high performance, monolithic 90% H202 catalyst bed previously developed and demonstrated. This approach to catalyst bed design and fabrication was an enabling technology to the ISTAR tri-fluid engine. The catalyst bed demonstrated 55 starts at throughputs greater than 0.60 lbm/s/sq in for a duration of over 900 seconds in a physical envelope approximately 114 of traditional designs. The catalyst bed uses photoetched plates of metal bonded into a single piece monolithic structure. The precise control of the geometry and complete mixing results in repeatable, quick starting, high performing catalyst bed. Three different beds were designed and tested, with the best performing bed used for tri-fluid engine testing.

  14. Digital control of highly augmented combat rotorcraft

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.

    1987-01-01

    Proposed concepts for the next generation of combat helicopters are to be embodied in a complex, highly maneuverable, multiroled vehicle with avionics systems. Single pilot and nap-of-the-Earth operations require handling qualities which minimize the involvement of the pilot in basic stabilization tasks. To meet these requirements will demand a full authority, high-gain, multimode, multiply-redundant, digital flight-control system. The gap between these requirements and current low-authority, low-bandwidth operational rotorcraft flight-control technology is considerable. This research aims at smoothing the transition between current technology and advanced concept requirements. The state of the art of high-bandwidth digital flight-control systems are reviewed; areas of specific concern for flight-control systems of modern combat are exposed; and the important concepts are illustrated in design and analysis of high-gain, digital systems with a detailed case study involving a current rotorcraft system. Approximate and exact methods are explained and illustrated for treating the important concerns which are unique to digital systems.

  15. Digitally Controlled High Availability Power Supply

    SciTech Connect

    MacNair, David; /SLAC

    2008-09-25

    This paper reports the design and test results on novel topology, high-efficiency, and low operating temperature, 1,320-watt power modules for high availability power supplies. The modules permit parallel operation for N+1 redundancy with hot swap capability. An embedded DSP provides intelligent start-up and shutdown, output regulation, general control and fault detection. PWM modules in the DSP drive the FET switches at 20 to 100 kHz. The DSP also ensures current sharing between modules, synchronized switching, and soft start up for hot swapping. The module voltage and current have dedicated ADCs (>200 kS/sec) to provide pulse-by-pulse output control. A Dual CAN bus interface provides for low cost redundant control paths. Over-rated module components provide high reliability and high efficiency at full load. Low on-resistance FETs replace conventional diodes in the buck regulator. Saturable inductors limit the FET reverse diode current during switching. The modules operate in a two-quadrant mode, allowing bipolar output from complimentary module groups. Controllable, low resistance FETs at the input and output provide fault isolation and allow module hot swapping.

  16. Strategy Guideline: Advanced Construction Documentation Recommendations for High Performance Homes

    SciTech Connect

    Lukachko, A.; Gates, C.; Straube, J.

    2011-12-01

    As whole house energy efficiency increases, new houses become less like conventional houses that were built in the past. New materials and new systems require greater coordination and communication between industry stakeholders. The Guideline for Construction Documents for High Performance Housing provides advice to address this need. The reader will be presented with four changes that are recommended to achieve improvements in energy efficiency, durability and health in Building America houses: create coordination drawings, improve specifications, improve detail drawings, and review drawings and prepare a Quality Control Plan.

  17. Benchmarking: More Aspects of High Performance Computing

    SciTech Connect

    Ravindrudu, Rahul

    2004-01-01

    The original HPL algorithm makes the assumption that all data can be fit entirely in the main memory. This assumption will obviously give a good performance due to the absence of disk I/O. However, not all applications can fit their entire data in memory. These applications which require a fair amount of I/O to move data to and from main memory and secondary storage, are more indicative of usage of an Massively Parallel Processor (MPP) System. Given this scenario a well designed I/O architecture will play a significant part in the performance of the MPP System on regular jobs. And, this is not represented in the current Benchmark. The modified HPL algorithm is hoped to be a step in filling this void. The most important factor in the performance of out-of-core algorithms is the actual I/O operations performed and their efficiency in transferring data to/from main memory and disk, Various methods were introduced in the report for performing I/O operations. The I/O method to use depends on the design of the out-of-core algorithm. Conversely, the performance of the out-of-core algorithm is affected by the choice of I/O operations. This implies, good performance is achieved when I/O efficiency is closely tied with the out-of-core algorithms. The out-of-core algorithms must be designed from the start. It is easily observed in the timings for various plots, that I/O plays a significant part in the overall execution time. This leads to an important conclusion, retro-fitting an existing code may not be the best choice. The right-looking algorithm selected for the LU factorization is a recursive algorithm and performs well when the entire dataset is in memory. At each stage of the loop the entire trailing submatrix is read into memory panel by panel. This gives a polynomial number of I/O reads and writes. If the left-looking algorithm was selected for the main loop, the number of I/O operations involved will be linear on the number of columns. This is due to the data access

  18. High bandwidth control of precision motion instrumentation

    NASA Astrophysics Data System (ADS)

    Bristow, Douglas A.; Dong, Jingyan; Alleyne, Andrew G.; Ferreira, Placid; Salapaka, Srinivas

    2008-10-01

    This article presents a high-bandwidth control design suitable for precision motion instrumentation. Iterative learning control (ILC), a feedforward technique that uses previous iterations of the desired trajectory, is used to leverage the repetition that occurs in many tasks, such as raster scanning in microscopy. Two ILC designs are presented. The first design uses the motion system dynamic model to maximize bandwidth. The second design uses a time-varying bandwidth that is particularly useful for nonsmooth trajectories such as raster scanning. Both designs are applied to a multiaxis piezoelectric-actuated flexure system and evaluated on a nonsmooth trajectory. The ILC designs demonstrate significant bandwidth and precision improvements over the feedback controller, and the ability to achieve precision motion control at frequencies higher than multiple system resonances.

  19. RISC Processors and High Performance Computing

    NASA Technical Reports Server (NTRS)

    Bailey, David H.; Saini, Subhash; Craw, James M. (Technical Monitor)

    1995-01-01

    This tutorial will discuss the top five RISC microprocessors and the parallel systems in which they are used. It will provide a unique cross-machine comparison not available elsewhere. The effective performance of these processors will be compared by citing standard benchmarks in the context of real applications. The latest NAS Parallel Benchmarks, both absolute performance and performance per dollar, will be listed. The next generation of the NPB will be described. The tutorial will conclude with a discussion of future directions in the field. Technology Transfer Considerations: All of these computer systems are commercially available internationally. Information about these processors is available in the public domain, mostly from the vendors themselves. The NAS Parallel Benchmarks and their results have been previously approved numerous times for public release, beginning back in 1991.

  20. High-performance holographic technologies for fluid-dynamics experiments

    PubMed Central

    Orlov, Sergei S.; Abarzhi, Snezhana I.; Oh, Se Baek; Barbastathis, George; Sreenivasan, Katepalli R.

    2010-01-01

    Modern technologies offer new opportunities for experimentalists in a variety of research areas of fluid dynamics. Improvements are now possible in the state-of-the-art in precision, dynamic range, reproducibility, motion-control accuracy, data-acquisition rate and information capacity. These improvements are required for understanding complex turbulent flows under realistic conditions, and for allowing unambiguous comparisons to be made with new theoretical approaches and large-scale numerical simulations. One of the new technologies is high-performance digital holography. State-of-the-art motion control, electronics and optical imaging allow for the realization of turbulent flows with very high Reynolds number (more than 107) on a relatively small laboratory scale, and quantification of their properties with high space–time resolutions and bandwidth. In-line digital holographic technology can provide complete three-dimensional mapping of the flow velocity and density fields at high data rates (over 1000 frames per second) over a relatively large spatial area with high spatial (1–10 μm) and temporal (better than a few nanoseconds) resolution, and can give accurate quantitative description of the fluid flows, including those of multi-phase and unsteady conditions. This technology can be applied in a variety of problems to study fundamental properties of flow–particle interactions, rotating flows, non-canonical boundary layers and Rayleigh–Taylor mixing. Some of these examples are discussed briefly. PMID:20211881