Negative coupled inductors for polyphase choppers

NASA Technical Reports Server (NTRS)

Jamieson, Robert S. (Inventor)

1984-01-01

A technique for negatively coupling the outputs of polyphase choppers is disclosed, wherein the output inductance of each phase is divided into two windings, and each winding is negatively coupled to a corresponding winding of a neighboring phase. In a preferred embodiment for a three-phase chopper circuit, the output inductance of phase A is divided into windings 100 and 102, the output inductance of phase B is divided into windings 110 and 112, and the output inductance of phase C is divided into windings 120 and 122. Pairs of windings 100 and 110, 112 and 120, and 102 and 122 are respectively disposed in transformers arranged for negatively coupling the windings of each pair.

A Spaceflight Magnetic Bearing Equipped Optical Chopper with Six-Axis Active Control

NASA Technical Reports Server (NTRS)

Blumenstock, Kenneth A.; Lee, Kenneth Y.; Schepis, Joseph P.

1998-01-01

This paper describes the development of an ETU (Engineering Test Unit) rotary optical chopper with magnetic bearings. An ETU is required to be both flight-like, nearly identical to a flight unit without the need for material certifications, and demonstrate structural and performance integrity. A prototype breadboard design previously demonstrated the feasibility of meeting flight performance requirements using magnetic bearings. The chopper mechanism is a critical component of the High Resolution Dynamics Limb Sounder (HIRDLS) which will be flown on EOS-CHEM (Earth Observing System-Chemistry). Particularly noteworthy are the science requirements which demand high precision positioning and minimal power consumption along with full redundancy of coils and sensors in a miniature, lightweight package. The magnetic bearings are unique in their pole design to minimize parasitic losses and utilize collocated optical sensing. The motor is of an unusual disk-type ironless stator design. The ETU design has evolved from the breadboard design. A number of improvements have been incorporated into the ETU design. Active thrust control has been added along with changes to improve sensor stability, motor efficiency, and touchdown and launch survivability. It was necessary to do all this while simultaneously reducing the mechanism volume. Flight-like electronics utilize a DSP (Digital Signal Processor) and contain all sensor electronics and drivers on a single five inch by nine inch circuit board. Performance test results are reported including magnetic bearing and motor rotational losses.

Development of optical choppers for time-resolved measurements at soft X-ray synchrotron radiation beamlines

PubMed Central

Osawa, Hitoshi; Ohkochi, Takuo; Fujisawa, Masami; Kimura, Shigeru; Kinoshita, Toyohiko

2017-01-01

Two types of optical choppers for time-resolved measurements at synchrotron radiation soft X-ray beamlines have been developed. One type uses an air-spindle-type rotation mechanism with a two-stage differential pumping system to maintain the ultra-high vacuum of the X-ray beamline, and the other uses a magnetic bearing. Both can be installed at the soft X-ray beamlines at SPring-8, greatly improving the accessibility of pump-and-probe spectroscopy. The combination of X-ray chopper and pump-and-probe photoemission electron microscope at SPring-8 provides drastic improvements in signal-to-noise ratio and resolution compared with techniques using high-voltage gating of channel plate detectors. The choppers have the capability to be used not only at synchrotron radiation facilities but also at other types of soft X-ray and VUV beamlines. PMID:28452746

Time-resolved spectroscopy using a chopper wheel as a fast shutter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shicong; Wendt, Amy E.; Boffard, John B.

Widely available, small form-factor, fiber-coupled spectrometers typically have a minimum exposure time measured in milliseconds, and thus cannot be used directly for time-resolved measurements at the microsecond level. Spectroscopy at these faster time scales is typically done with an intensified charge coupled device (CCD) system where the image intensifier acts as a “fast” electronic shutter for the slower CCD array. In this paper, we describe simple modifications to a commercially available chopper wheel system to allow it to be used as a “fast” mechanical shutter for gating a fiber-coupled spectrometer to achieve microsecond-scale time-resolved optical measurements of a periodically pulsedmore » light source. With the chopper wheel synchronized to the pulsing of the light source, the time resolution can be set to a small fraction of the pulse period by using a chopper wheel with narrow slots separated by wide spokes. Different methods of synchronizing the chopper wheel and pulsing of the light sources are explored. The capability of the chopper wheel system is illustrated with time-resolved measurements of pulsed plasmas.« less

Vehicle test report: South Coast Technology electric Volkswagen Rabbit with developmental low-power armature chopper

NASA Technical Reports Server (NTRS)

Marte, J. E.; Bryant, J. A.; Livingston, R.

1983-01-01

Dynamometer performance of a South Coast Technology electric conversion of a Volkswagen (VW) Rabbit designated SCT-8 was tested. The SCT-8 vehicle was fitted with a transistorized chopper in the motor armature circuit to supplement the standard motor speed control via field weakening. The armature chopper allowed speed control below the motor base speed. This low speed control was intended to reduce energy loss at idle during stop-and-go traffic; to eliminate the need for using the clutch below base motor speed; and to improve the drivability. Test results indicate an improvement of about 3.5% in battery energy economy for the SAE J227a-D driving cycle and 6% for the C-cycle with only a minor reduction in acceleration performance. A further reduction of about 6% would be possible if provision were made for shutting down field power during the idle phases of the driving cycles. Drivability of the vehicle equipped with the armature chopper was significantly improved compared with the standard SCT Electric Rabbit.

A 16-Channel CMOS Chopper-Stabilized Analog Front-End ECoG Acquisition Circuit for a Closed-Loop Epileptic Seizure Control System.

PubMed

Wu, Chung-Yu; Cheng, Cheng-Hsiang; Chen, Zhi-Xin

2018-06-01

In this paper, a 16-channel analog front-end (AFE) electrocorticography signal acquisition circuit for a closed-loop seizure control system is presented. It is composed of 16 input protection circuits, 16 auto-reset chopper-stabilized capacitive-coupled instrumentation amplifiers (AR-CSCCIA) with bandpass filters, 16 programmable transconductance gain amplifiers, a multiplexer, a transimpedance amplifier, and a 128-kS/s 10-bit delta-modulated successive-approximation-register analog-to-digital converter (SAR ADC). In closed-loop seizure control system applications, the stimulator shares the same electrode with the AFE amplifier for effective suppression of epileptic seizures. To prevent from overstress in MOS devices caused by high stimulation voltage, an input protection circuit with a high-voltage-tolerant switch is proposed for the AFE amplifier. Moreover, low input-referred noise is achieved by using the chopper modulation technique in the AR-CSCCIA. To reduce the undesired effects of chopper modulation, an improved offset reduction loop is proposed to reduce the output offset generated by input chopper mismatches. The digital ripple reduction loop is also used to reduce the chopper ripple. The fabricated AFE amplifier has 49.1-/59.4-/67.9-dB programmable gain and 2.02-μVrms input referred noise in a bandwidth of 0.59-117 Hz. The measured power consumption of the AFE amplifier is 3.26 μW per channel, and the noise efficiency factor is 3.36. The in vivo animal test has been successfully performed to verify the functions. It is shown that the proposed AFE acquisition circuit is suitable for implantable closed-loop seizure control systems.

FAST CHOPPER BUILDING, TRA665. DETAIL SHOWS UPPER AND LOWER LEVEL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAST CHOPPER BUILDING, TRA-665. DETAIL SHOWS UPPER AND LOWER LEVEL WALLS OF DIFFERING MATERIALS. NOTE DOORWAY TO MTR TO RIGHT OF CHOPPER BUILDING'S CLIPPED CORNER. CAMERA FACING WEST. INL NEGATIVE NO. HD42-1. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

FAST CHOPPER DETECTOR HOUSE, TRA665. SECOND FLOOR ADDITION: PLAN, SECTIONS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAST CHOPPER DETECTOR HOUSE, TRA-665. SECOND FLOOR ADDITION: PLAN, SECTIONS AND DETAILS AS ADDED TO THE EXISTING CHOPPER HOUSE IN 1962. F.C. TORKELSON 842-MTR-665-S-3, 4/1962. INL INDEX NO. 531-0665-60-851-150997, REV. 3. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

ARCS A wide-Anglular Range Chopper Spectrometer at the SNS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prof. Brent Fultz; Dr. Doug Abernathy

The ARCS spectrometer project has been funded for 39 months. Procurements are now amain activity, although engineering effort remains, and installation has begun. Most of the subsystems are under control, and represent no risk to the project. These are: cryo-goniometer, detectors and electronics, Fermi chopper system, computing cluster, basic reduction software, T0 chopper and main neutron guide. The sample hutch and radiationshielding are still items of some risk. At the time of this writing, we are awaiting vendor proposals for the scattering chamber with integrated sample isolation system. This is thelargest uncertainty in the ARCS project today. The ARCS Chiefmore » Engineer, Kevin Shaw, joined the project in 2004. Project controlsservices are now performed by the SNS. A construction progress review was held in the August, 2004, before which the project was rebaselined, and after which the ProjectExecution Plan was updated. The ARCS project will be rebaselined in March 2005 after a vendor is selected for the scattering chamber with integrated isolation system. Projectcompletion by Sept. 2006 is possible but challenging.« less

FAST CHOPPER BUILDING, TRA665. CAMERA FACING NORTH. NOTE BRICKEDIN WINDOW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAST CHOPPER BUILDING, TRA-665. CAMERA FACING NORTH. NOTE BRICKED-IN WINDOW ON RIGHT SIDE (BELOW PAINTED NUMERALS "665"). SLIDING METAL DOOR ON COVERED RAIL AT UPPER LEVEL. SHELTERED ENTRANCE TO STEEL SHIELDING DOOR. DOOR INTO MTR SERVICE BUILDING, TRA-635, STANDS OPEN. MTR BEHIND CHOPPER BUILDING. INL NEGATIVE NO. HD42-1. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Rapid and economical data acquisition in ultrafast frequency-resolved spectroscopy using choppers and a microcontroller.

PubMed

Guo, Liang; Monahan, Daniele M; Fleming, Graham

2016-08-08

Spectrometers and cameras are used in ultrafast spectroscopy to achieve high resolution in both time and frequency domains. Frequency-resolved signals from the camera pixels cannot be processed by common lock-in amplifiers, which have only a limited number of input channels. Here we demonstrate a rapid and economical method that achieves the function of a lock-in amplifier using mechanical choppers and a programmable microcontroller. We demonstrate the method's effectiveness by performing a frequency-resolved pump-probe measurement on the dye Nile Blue in solution.

Chopper herbicide site preparation for different bedding timings and vegetation complexes in North Florida

Treesearch

Dwight K. Lauer; Harold E. Quicke; David Adams

2006-01-01

The use of Chopper® (BASF Corporation, Research Triangle Park, NC) herbicide applied with an oil and water carrier was tested for site preparation. Tests were installed at eight locations to examine slash pine (Pinus elliottii Engelm.) response and vegetation control with different vegetation types and timings of bedding. Chopper was applied in...

Up-and-down chopper circuit

DOEpatents

Goffeau, Jacques R.

1979-01-01

An improved Up-and-Down Chopper Circuit is provided which is useful for voltage regulation in a bi-directional DC power system. In the down mode, power is switched from a DC power source to a lower voltage energy storing load while in the up mode stored energy in the load is transferred to the higher voltage source. The system uses Darlington transistor switches in a conventional connection. The improvement relates to circuit additions to eliminate the effects of inter-electrode capacitance inherent with this Darlington transistor switching arrangement.

Optical Chopper Assembly for the Mars Observer

NASA Technical Reports Server (NTRS)

Allen, Terry

1993-01-01

This paper describes the Honeywell-developed Optical Chopper Assembly (OCA), a component of Mars Observer spacecraft's Pressure Modulator Infrared Radiometer (PMIRR) science experiment, which will map the Martian atmosphere during 1993 to 1995. The OCA is unique because of its constant accurate rotational speed, low electrical power consumption, and long-life requirements. These strict and demanding requirements were achieved by use of a number of novel approaches.

Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 1: Test program results and recommendations

NASA Technical Reports Server (NTRS)

Hamilton, H. B.; Strangas, E.

1980-01-01

The conventional series motor model is discussed as well as procedures for obtaining, by test, the parameters necessary for calculating performance and losses. The calculated results for operation from ripple free DC are compared with observed test results, indicating approximately 5% or less error. Experimental data indicating the influence of brush shift and chopper frequency are also presented. Both factors have a significant effect on the speed and torque relationships. The losses and loss mechanisms present in a DC series motor are examined and an attempt is made to evaluate the added losses due to harmonic currents and fluxes. Findings with respect to these losses is summarized.

Mode-Locked Spike Trains in Responses of Ventral Cochlear Nucleus Chopper and Onset Neurons to Periodic Stimuli

PubMed Central

Laudanski, Jonathan; Coombes, Stephen; Palmer, Alan R.

2010-01-01

We report evidence of mode-locking to the envelope of a periodic stimulus in chopper units of the ventral cochlear nucleus (VCN). Mode-locking is a generalized description of how responses in periodically forced nonlinear systems can be closely linked to the input envelope, while showing temporal patterns of higher order than seen during pure phase-locking. Re-analyzing a previously unpublished dataset in response to amplitude modulated tones, we find that of 55% of cells (6/11) demonstrated stochastic mode-locking in response to sinusoidally amplitude modulated (SAM) pure tones at 50% modulation depth. At 100% modulation depth SAM, most units (3/4) showed mode-locking. We use interspike interval (ISI) scattergrams to unravel the temporal structure present in chopper mode-locked responses. These responses compared well to a leaky integrate-and-fire model (LIF) model of chopper units. Thus the timing of spikes in chopper unit responses to periodic stimuli can be understood in terms of the complex dynamics of periodically forced nonlinear systems. A larger set of onset (33) and chopper units (24) of the VCN also shows mode-locked responses to steady-state vowels and cosine-phase harmonic complexes. However, while 80% of chopper responses to complex stimuli meet our criterion for the presence of mode-locking, only 40% of onset cells show similar complex-modes of spike patterns. We found a correlation between a unit's regularity and its tendency to display mode-locked spike trains as well as a correlation in the number of spikes per cycle and the presence of complex-modes of spike patterns. These spiking patterns are sensitive to the envelope as well as the fundamental frequency of complex sounds, suggesting that complex cell dynamics may play a role in encoding periodic stimuli and envelopes in the VCN. PMID:20042702

Hard disk drive based microsecond X-ray chopper for characterization of ionization chambers and photodiodes.

PubMed

Müller, O; Lützenkirchen-Hecht, D; Frahm, R

2015-03-01

A fast X-ray chopper capable of producing ms long X-ray pulses with a typical rise time of few μs was realized. It is ideally suited to investigate the temporal response of X-ray detectors with response times of the order of μs to ms, in particular, any kind of ionization chambers and large area photo diodes. The drive mechanism consists of a brushless DC motor and driver electronics from a common hard disk drive, keeping the cost at an absolute minimum. Due to its simple construction and small dimensions, this chopper operates at home lab based X-ray tubes and synchrotron radiation sources as well. The dynamics of the most important detectors used in time resolved X-ray absorption spectroscopy, namely, ionization chambers and Passivated Implanted Planar Silicon photodiodes, were investigated in detail. The results emphasize the applicability of this X-ray chopper.

Effect of application timing on efficacy of site preparation treatments using Chopper® GEN2™

Treesearch

A.W. Ezell; J.L. Yeiser; D.K. Lauer; H.E. Quicke

2013-01-01

Chopper® GEN2™ is a new imazapyr product for use in forestry site preparation. A single treatment (32 ounces of Chopper® GEN2™ per acre) was applied at three timings on three sites (Louisiana, Mississippi, and Virginia) to test the effect of application timing on treatment efficacy. Hardwood control was excellent for all applications. Pine growth varied by site, but...

FAST CHOPPER BUILDING, TRA665, INTERIOR. UPPER LEVEL. CONCRETE WALLS. INL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAST CHOPPER BUILDING, TRA-665, INTERIOR. UPPER LEVEL. CONCRETE WALLS. INL NEGATIVE NO. HD42-2. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Performance of a 14.9-kW laminated-frame dc series motor with chopper controller

NASA Technical Reports Server (NTRS)

Schwab, J. R.

1979-01-01

Traction motor using two types of excitation: ripple free dc from a motor generator set for baseline data and chopped dc as supplied by a battery and chopper controller was tested. For the same average values of input voltage and current, the power output was independent of the type of excitation. At the same speeds, motor efficiency at low power output (corresponding to low duty cycle of the controller) was 5 to 10 percentage points less on chopped dc than on ripple-free dc. This illustrates that for chopped waveforms, it is incorrect to calculate input power as the product of average voltage and average current. Locked-rotor torque, no load losses, and magnetic saturation data were so determined.

Performance of 22.4-kW nonlaminated-frame dc series motor with chopper controller. [a dc to dc voltage converter

NASA Technical Reports Server (NTRS)

Schwab, J. R.

1979-01-01

Performance data obtained through experimental testing of a 22.4 kW traction motor using two types of excitation are presented. Ripple free dc from a motor-generator set for baseline data and pulse width modulated dc as supplied by a battery pack and chopper controller were used for excitation. For the same average values of input voltage and current, the motor power output was independent of the type of excitation. However, at the same speeds, the motor efficiency at low power output (corresponding to low duty cycle of the controller) was 5 to 10 percentage points lower on chopped dc than on ripple free dc. The chopped dc locked-rotor torque was approximately 1 to 3 percent greater than the ripple free dc torque for the same average current.

FAST CHOPPER BUILDING, TRA665. DETAIL OF STEEL DOOR ENTRY TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAST CHOPPER BUILDING, TRA-665. DETAIL OF STEEL DOOR ENTRY TO LOWER LEVEL. CAMERA FACING NORTH. INL NEGATIVE NO. HD42-1. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Productivity of a large-wheeled skidder and roller chopper for preparing sites.

Treesearch

Edwin S. Miyata; Helmuth M. Steinhilb; Glenn D. Mroz; Lynne A. Coyer

1983-01-01

Discusses the results of a field test of a Pettibone Master 1500 skidder and Flecor Corporation SS812 roller chopper for site preparation work in Wisconsin. Includes cost, productivity, and effectiveness of site preparation on 23.4 acres (9.47 ha).

Performance advantages of maximum likelihood methods in PRBS-modulated time-of-flight electron energy loss spectroscopy

NASA Astrophysics Data System (ADS)

Yang, Zhongyu

This thesis describes the design, experimental performance, and theoretical simulation of a novel time-of-flight analyzer that was integrated into a high resolution electron energy loss spectrometer (TOF-HREELS). First we examined the use of an interleaved comb chopper for chopping a continuous electron beam. Both static and dynamic behaviors were simulated theoretically and measured experimentally, with very good agreement. The finite penetration of the field beyond the plane of the chopper leads to non-ideal chopper response, which is characterized in terms of an "energy corruption" effect and a lead or lag in the time at which the beam responds to the chopper potential. Second we considered the recovery of spectra from pseudo-random binary sequence (PRBS) modulated TOF-HREELS data. The effects of the Poisson noise distribution and the non-ideal behavior of the "interleaved comb" chopper were simulated. We showed, for the first time, that maximum likelihood methods can be combined with PRBS modulation to achieve resolution enhancement, while properly accounting for the Poisson noise distribution and artifacts introduced by the chopper. Our results indicate that meV resolution, similar to that of modern high resolution electron energy loss spectrometers, can be achieved with a dramatic performance advantage over conventional, serial detection analyzers. To demonstrate the capabilities of the TOF-HREELS instrument, we made measurements on a highly oriented thin film polytetrafluoroethylene (PTFE) sample. We demonstrated that the TOF-HREELS can achieve a throughput advantage of a factor of 85 compared to the conventional HREELS instrument. Comparisons were made between the experimental results and theoretical simulations. We discuss various factors which affect inversion of PRBS modulated Time of Flight (TOF) data with the Lucy algorithm. Using simulations, we conclude that the convolution assumption was good under the conditions of our experiment. The chopper rise

The safety aspects of chopper motorcycles : a literature survey in response to HJR #90.

DOT National Transportation Integrated Search

1974-01-01

This study was initiated to examine certain safety characteristics of modified motorcycles. Are motorcycles which can be classified as "choppers" less safe than standard, retail, stock machines? Do personal modifications differ from professional modi...

FAST CHOPPER BUILDING, TRA665, INTERIOR. LOWER (DETECTOR) LEVEL. NOTE BRICKEDIN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAST CHOPPER BUILDING, TRA-665, INTERIOR. LOWER (DETECTOR) LEVEL. NOTE BRICKED-IN WINDOW ON MTR SIDE. USED FOR STORAGE OF LEAD BRICKS AFTER EXPERIMENTAL NEUTRON INSTRUMENTS WERE REMOVED. SIGN SAYS "IN-PROCESS LEAD SOURCE STORAGE." INL NEGATIVE NO. HD-42-2. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Response of lead-acid batteries to chopper-controlled discharge

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses at up to 25 percent compared to constant current discharges at the same average discharge current of 100 A. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-A pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

Application of MEMS-based x-ray optics as tuneable nanosecond choppers

NASA Astrophysics Data System (ADS)

Chen, Pice; Walko, Donald A.; Jung, Il Woong; Li, Zhilong; Gao, Ya; Shenoy, Gopal K.; Lopez, Daniel; Wang, Jin

2017-08-01

Time-resolved synchrotron x-ray measurements often rely on using a mechanical chopper to isolate a set of x-ray pulses. We have started the development of micro electromechanical systems (MEMS)-based x-ray optics, as an alternate method to manipulate x-ray beams. In the application of x-ray pulse isolation, we recently achieved a pulse-picking time window of half a nanosecond, which is more than 100 times faster than mechanical choppers can achieve. The MEMS device consists of a comb-drive silicon micromirror, designed for efficiently diffracting an x-ray beam during oscillation. The MEMS devices were operated in Bragg geometry and their oscillation was synchronized to x-ray pulses, with a frequency matching subharmonics of the cycling frequency of x-ray pulses. The microscale structure of the silicon mirror in terms of the curvature and the quality of crystallinity ensures a narrow angular spread of the Bragg reflection. With the discussion of factors determining the diffractive time window, this report showed our approaches to narrow down the time window to half a nanosecond. The short diffractive time window will allow us to select single x-ray pulse out of a train of pulses from synchrotron radiation facilities.

The performance and efficiency of four motor/controller/battery systems for the simpler electric vehicles

NASA Technical Reports Server (NTRS)

Shipps, P. R.

1980-01-01

A test and analysis program performed on four complete propulsion systems for an urban electric vehicle (EV) is described and results given. A dc series motor and a permanent magnet (PM) motor were tested, each powered by an EV battery pack and controlled by (1) a series/parallel voltage-switching (V-switch) system; and (2) a system using a pulse width modulation, 400 Hz transistorized chopper. Dynamometer tests were first performed, followed by eV performance predictions and data correlating road tests. During dynamometer tests using chopper control; current, voltage, and power were measured on both the battery and motor sides of the chopper, using three types of instrumentation. Conventional dc instruments provided adequate accuracy for eV power and energy measurements, when used on the battery side of the controller. When using the chopper controller, the addition of a small choke inductor improved system efficiency in the lower duty cycle range (some 8% increase at 50% duty cycle) with both types of motors. Overall system efficiency rankings during road tests were: (1) series motor with V-switch; (2) PM motor with V-switch; (3) series motor with chopper; and (4) PM motor with chopper. Chopper control of the eV was smoother and required less driver skill than V-switch control.

The front end test stand high performance H- ion source at Rutherford Appleton Laboratory.

PubMed

Faircloth, D C; Lawrie, S; Letchford, A P; Gabor, C; Wise, P; Whitehead, M; Wood, T; Westall, M; Findlay, D; Perkins, M; Savage, P J; Lee, D A; Pozimski, J K

2010-02-01

The aim of the front end test stand (FETS) project is to demonstrate that chopped low energy beams of high quality can be produced. FETS consists of a 60 mA Penning Surface Plasma Ion Source, a three solenoid low energy beam transport, a 3 MeV radio frequency quadrupole, a chopper, and a comprehensive suite of diagnostics. This paper details the design and initial performance of the ion source and the laser profile measurement system. Beam current, profile, and emittance measurements are shown for different operating conditions.

MTR, TRA603. FIRST FLOOR PLAN. REACTOR AT CENTER. TWENTYMETER CHOPPER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

MTR, TRA-603. FIRST FLOOR PLAN. REACTOR AT CENTER. TWENTY-METER CHOPPER HOUSE. COFFIN TURNING ROLLS. REMOVABLE PANEL OVER CANAL ON EAST SIDE. NEW PLUG STORAGE ACCESS. DOOR SCHEDULE INDICATES STEEL (FOR VAULT), WIRE MESH, AND HOLLOW METAL TYPES. STORAGE AND ISSUE ROOM. SAFETY SHOWERS. DOORWAY TO WING, TRA-604. BLAW-KNOX 3150-803-2, 7/1950. INL INDEX NO. 531-0603-00-098-100561, REV. 10. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Micro EEG/ECG signal’s chopper-stabilization amplifying chip for novel dry-contact electrode

NASA Astrophysics Data System (ADS)

Sun, Jianhui; Wang, Chunxing; Wang, Gongtang; Wang, Jinhui; Hua, Qing; Cheng, Chuanfu; Cai, Xinxia; Yin, Tao; Yu, Yang; Yang, Haigang; Li, Dengwang

2017-02-01

Facing the body’s EEG (electroencephalograph, 0.5–100 Hz, 5–100 μV) and ECG’s (electrocardiogram, < 100 {Hz}, 0.01–5 mV) micro signal detection requirement, this paper develops a pervasive application micro signal detection ASIC chip with the chopping modulation/demodulation method. The chopper-stabilization circuit with the RRL (ripple reduction loop) circuit is to suppress the ripple voltage, which locates at the single-stage amplifier’s outputting terminal. The single-stage chopping core’s noise has been suppressed too, and it is beneficial for suppressing noises of post-circuit. The chopping core circuit uses the PFB (positive feedback loop) to increase the inputting resistance, and the NFB (negative feedback loop) to stabilize the 40 dB intermediate frequency gain. The cascaded switch-capacitor sample/hold circuit has been used for deleting spike noises caused by non-ideal MOS switches, and the VGA/BPF (voltage gain amplifier/band pass filter) circuit is used to tune the chopper system’s gain/bandwidth digitally. Assisted with the designed novel dry-electrode, the real test result of the chopping amplifying circuit gives some critical parameters: 8.1 μW/channel, 0.8 μVrms (@band-width = 100 Hz), 4216–11220 times digitally tuning gain range, etc. The data capture system uses the NI CO’s data capturing DAQmx interface, and the captured micro EEG/ECG’s waves are real-time displayed with the PC-Labview. The proposed chopper system is a unified EEG/ECG signal’s detection instrument and has a critical real application value. Project supported by the National Natural Science Foundation of China (Nos. 61527815, 31500800, 61501426, 61471342), the National Key Basic Research Plan (No. 2014CB744600), the Beijing Science and Technology Plan (No. Z141100000214002), and the Chinese Academy of Sciences’ Key Project (No. KJZD-EW-L11-2).

Response of lead-acid batteries to chopper-controlled discharge: Preliminary results

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses up to 25 percent compared to constant current discharges at the same average discharge current of 100 amperes. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-ampere pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

Rapid Optical Shutter, Chopper, Modulator and Deflector

NASA Technical Reports Server (NTRS)

Danehy, Paul M. (Inventor)

2017-01-01

An optical device with a light source and a detector is provided. A digital micromirror device positioned between the detector and the light source may deflect light beams projected from the light source. An aperture in front of the detector may block an incoming light beam from the detector when the incoming light beam is incident on the detector outside of a passable incident range and including an aperture opening configured to pass the incoming light beam to the detector when the incoming light beam is incident on the detector within a passable incident range. The digital micromirror device may rotate between a first position causing the light beam to pass through the aperture opening and a second position causing the light beam to be blocked by the aperture. The optical device may be configured to operate as a shutter, chopper, modulator and/or deflector.

Losses in chopper-controlled DC series motors

NASA Technical Reports Server (NTRS)

Hamilton, H. B.

1982-01-01

Motors for electric vehicle (EV) applications must have different features than dc motors designed for industrial applications. The EV motor application is characterized by the following requirements: (1) the need for highest possible efficiency from light load to overload, for maximum EV range, (2) large short time overload capability (The ratio of peak to average power varies from 5/1 in heavy city traffic to 3/1 in suburban driving situations) and (3) operation from power supply voltage levels of 84 to 144 volts (probably 120 volts maximum). A test facility utilizing a dc generator as a substitute for a battery pack was designed and utilized. Criteria for the design of such a facility are presented. Two motors, differing in design detail, commercially available for EV use were tested. Losses measured are discussed, as are waves forms and their harmonic content, the measurements of resistance and inductance, EV motor/chopper application criteria, and motor design considerations.

A chopper system for shortening the duration of pulsed supersonic beams seeded with NO or Br2 down to 13 μs.

PubMed

Lam, Jessica; Rennick, Christopher J; Softley, Timothy P

2015-05-01

A chopper wheel construct is used to shorten the duration of a molecular beam to 13 μs. Molecular beams seeded with NO or with Br2 and an initial pulse width of ≥200 μs were passed through a spinning chopper wheel, which was driven by a brushless DC in vacuo motor at a range of speeds, from 3000 rpm to 80,000 rpm. The resulting duration of the molecular-beam pulses measured at the laser detection volume ranged from 80 μs to 13 μs and was the same for both NO and Br2. The duration is consistent with a simple analytical model, and the minimum pulse width measured is limited by the spreading of the beam between the chopper and the detection point as a consequence of the longitudinal velocity distribution of the beam. The setup adopted here effectively eliminates buildup of background gas without the use of a differential pumping stage, and a clean narrow pulse is obtained with low rotational temperature.

Response of lead-acid batteries to chopper-controlled discharge. [for electric vehicles

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The results of tests on an electric vehicle battery, using a simulated electric vehicle chopper-speed controller, show energy output losses up to 25 percent compared to constant current discharges at the same average current of 100 A. However, an energy output increase of 22 percent is noticed at the 200 A average level and 44 percent increase at the 300 A level using pulse discharging. Because of these complex results, electric vehicle battery/speed controller interactions must be considered in vehicle design.

Posterior segment nucleotomy for dislocated sclerotic cataractous lens using chandelier endoilluminator and sharp tipped chopper

PubMed Central

Takkar, Brijesh; Azad, Rajvardhan; Azad, Shorya; Rathi, Anubha

2015-01-01

AIM To describe a new surgical technique for managing dislocated sclerotic cataractous lens. METHODS Six patients with advanced posteriorly dislocated cataracts were operated at a tertiary care centre and analyzed retrospectively. After standard 3 port 23 G pars plana vitrectomy and perfluorocarbon liquid (PFCL) injection, the dislocated white cataract was held with occlusion using phaco fragmatome and then chopped into smaller pieces with a sharp tipped chopper using 25 G chandelier endoilluminator. Each piece was emulsified individually. Following aspiration of PFCL, Fluid Air Exchange was done in all the cases and surgery completed uneventfully. RESULTS Best corrected visual acuity (BCVA) in all the patients was better than 6/12 after one month of follow up. No serious complications were noted till minimum 6mo of follow up. CONCLUSION Four port posterior segment nucleotomy with a chandelier endoilluminator, fragmatome and a chopper appears to be a safe, easy and effective procedure for managing dislocated sclerotic cataractous nuclei. Ultrasonic energy used and adverse thermal effects of the fragmatome on the sclera may be lesser. PMID:26309887

Intracellular responses of onset chopper neurons in the ventral cochlear nucleus to tones: evidence for dual-component processing.

PubMed

Paolini, A G; Clark, G M

1999-05-01

Intracellular responses of onset chopper neurons in the ventral cochlear nucleus to tones: evidence for dual-component processing. The ventral cochlear nucleus (VCN) contains a heterogeneous collection of cell types reflecting the multiple processing tasks undertaken by this nucleus. This in vivo study in the rat used intracellular recordings and dye filling to examine membrane potential changes and firing characteristics of onset chopper (OC) neurons to acoustic stimulation (50 ms pure tones, 5 ms r/f time). Stable impalements were made from 15 OC neurons, 7 identified as multipolar cells. Neurons responded to characteristic frequency (CF) tones with sustained depolarization below spike threshold. With increasing stimulus intensity, the depolarization during the initial 10 ms of the response became peaked, and with further increases in intensity the peak became narrower. Onset spikes were generated during this initial depolarization. Tones presented below CF resulted in a broadening of this initial depolarizing component with high stimulus intensities required to initiate onset spikes. This initial component was followed by a sustained depolarizing component lasting until stimulus cessation. The amplitude of the sustained depolarizing component was greatest when frequencies were presented at high intensities below CF resulting in increased action potential firing during this period when compared with comparable high intensities at CF. During the presentation of tones at or above the high-frequency edge of a cell's response area, hyperpolarization was evident during the sustained component. The presence of hyperpolarization and the differences seen in the level of sustained depolarization during CF and off CF tones suggests that changes in membrane responsiveness between the initial and sustained components may be attributed to polysynaptic inhibitory mechanisms. The dual-component processing resulting from convergent auditory nerve excitation and polysynaptic

The cold neutron chopper spectrometer at the Spallation Neutron Source—A review of the first 8 years of operation

DOE PAGES

Ehlers, G.; Podlesnyak, A. A.; Kolesnikov, A. I.

2016-09-13

The first eight years of operation of the Cold Neutron Chopper Spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge is being reviewed. The instrument has been part of the facility user program since 2009, and more than 250 individual user experiments have been performed to date. CNCS is an extremely powerful and versatile instrument and offers leading edge performance in terms of beam intensity, energy resolution, and flexibility to trade one for another. In addition, experiments are being routinely performed with the sample at extreme conditions: T ≲ 0.05 K, p ≳ 2 GPa, and B = 8more » T can be achieved individually or in combination. In particular, CNCS is in a position to advance the state of the art with inelastic neutron scattering under pressure, and some of the recent accomplishments in this area will be presented in more detail.« less

Multiple high voltage output DC-to-DC power converter

NASA Technical Reports Server (NTRS)

Cronin, Donald L. (Inventor); Farber, Bertrand F. (Inventor); Gehm, Hartmut K. (Inventor); Goldin, Daniel S. (Inventor)

1977-01-01

Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level at a selected output.

Results of chopper-controlled discharge life cycling studies on lead acid batteries

NASA Technical Reports Server (NTRS)

Ewashinka, J. G.; Sidik, S. M.

1982-01-01

A group of 108 state of the art nominally 6 volt lead acid batteries were tested in a program of one charge/discharge cycle per day for over two years or to ultimate battery failure. The primary objective was to determine battery cycle life as a function of depth of discharge (25 to 75 percent), chopper frequency (100 to 1000 Hz), duty cycle (25 to 87.5 percent), and average discharge current (20 to 260 A). The secondary objective was to determine the types of battery failure modes, if any, were due to the above parameters. The four parameters above were incorporated in a statistically designed test program.

Timing of chopper herbicide site preparation relative to bedding in the establishment of lower coastal plain pine plantations

Treesearch

Dwight K. Lauer; Harold E. Quicke

2006-01-01

The timing of Chopper® (BASF Corporation, Research Triangle Park, NC) herbicide applications before and after bedding was examined at four Lower Coastal Plain locations. Two bedding regimes, mid-season and late-season, were included at each location. Mid-season bedding occurred between May and July and late-season bedding between September and November. No post-plant...

Note: Demodulation of spectral signal modulated by optical chopper with unstable modulation frequency.

PubMed

Zhang, Shengzhao; Li, Gang; Wang, Jiexi; Wang, Donggen; Han, Ying; Cao, Hui; Lin, Ling; Diao, Chunhong

2017-10-01

When an optical chopper is used to modulate the light source, the rotating speed of the wheel may vary with time and subsequently cause jitter of the modulation frequency. The amplitude calculated from the modulated signal would be distorted when the frequency fluctuations occur. To precisely calculate the amplitude of the modulated light flux, we proposed a method to estimate the range of the frequency fluctuation in the measurement of the spectrum and then extract the amplitude based on the sum of power of the signal in the selected frequency range. Experiments were designed to test the feasibility of the proposed method and the results showed lower root means square error than the conventional way.

Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 2: The time dependent finite element modeling of the electromagnetic field in electrical machines: Methods and applications. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Hamilton, H. B.; Strangas, E.

1980-01-01

The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.

Capacitor regenerative braking system of electric wheelchair for senior citizen based on variable frequency chopper control.

PubMed

Takahashi, Yoshiaki; Seki, Hirokazu

2009-01-01

This paper proposes a novel regenerative braking control system of electric wheelchairs for senior citizen. "Electric powered wheelchair", which generates the driving force by electric motors according to the human operation, is expected to be widely used as a mobility support system for elderly people. This study focuses on the braking control to realize the safety and smooth stopping motion using the regenerative braking control technique based on fuzzy algorithm. The ride quality improvement and energy recycling can be expected by the proposed control system with stopping distance estimation and variable frequency control on the step-up/down chopper type of capacitor regenerative circuit. Some driving experiments confirm the effectiveness of the proposed control system.

High precision moving magnet chopper for variable operation conditions

NASA Technical Reports Server (NTRS)

Aicher, Winfried; Schmid, Manfred

1994-01-01

In the context of an ESTEC technology contract, a Chopping Mechanism was developed and built with the Far Infrared and Submillimeter Telescope (FIRST) astronomy mission as a reference. The task of the mechanism is to tilt the subreflector of the telescope with an assumed mass of 2.5 kg about one chopping axis at nominal frequencies of up to 5 Hz and chopping angles of up to +/- 11.25 mrad with high efficiency (minimum time for position change). The chopping axis is required to run through the subreflector vertex. After performing a concept trade-off also considering the low operational temperatures in the 130 K range, a design using moving magnet actuators was found to be the favorite one. In addition, a bearing concept using flexible pivots was chosen to meet the high chopping accuracy required. With this approach, a very reliable design could be realized, since the actuators work without any mechanical contact between its moving and fixed parts, and the only bearings used are two flexible pivots supporting the subreflector mounting interface. The mechanism was completely built in titanium in a lightweight and stiff design. The moving magnet actuators were designed to meet the stringent requirements for minimum risetime (time necessary to move from one angular position to a new one) in the 20 msec range. The angular position and the corresponding chopping frequency as well can be arbitrarily selected by the user.

High-Speed, high-power, switching transistor

NASA Technical Reports Server (NTRS)

Carnahan, D.; Ohu, C. K.; Hower, P. L.

1979-01-01

Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cammarata, Marco; Eybert, Laurent; Ewald, Friederike

A chopper system for time resolved pump-probe experiments with x-ray beams from a synchrotron is described. The system has three parts: a water-cooled heatload chopper, a high-speed chopper, and a millisecond shutter. The chopper system, which is installed in beamline ID09B at the European Synchrotron Radiation Facility, provides short x-ray pulses for pump-probe experiments with ultrafast lasers. The chopper system can produce x-ray pulses as short as 200 ns in a continuous beam and repeat at frequencies from 0 to 3 kHz. For bunch filling patterns of the synchrotron with pulse separations greater than 100 ns, the high-speed chopper canmore » isolate single 100 ps x-ray pulses that are used for the highest time resolution. A new rotor in the high-speed chopper is presented with a single pulse (100 ps) and long pulse (10 {mu}s) option. In white beam experiments, the heatload of the (noncooled) high-speed chopper is lowered by a heatload chopper, which absorbs 95% of the incoming power without affecting the pulses selected by the high speed chopper.« less

Performance of Electric Double-Layer Capacitor Simulators

NASA Astrophysics Data System (ADS)

Funabiki, Shigeyuki; Kodama, Shinsuke; Yamamoto, Masayoshi

This paper proposes a simulator of EDLC, which realizes the performance equivalent to electric double-layer capacitors (EDLCs). The proposed simulator consists of an electrolytic capacitor and a two-quadrant chopper working as a current source. Its operation principle is described in the first place. The voltage dependence of capacitance of EDLCs is taken into account. The performance of the proposed EDLC simulator is verified by computer simulations.

A Low-Voltage Chopper-Stabilized Amplifier for Fetal ECG Monitoring With a 1.41 Power Efficiency Factor.

PubMed

Song, Shuang; Rooijakkers, Michael; Harpe, Pieter; Rabotti, Chiara; Mischi, Massimo; van Roermund, Arthur H M; Cantatore, Eugenio

2015-04-01

This paper presents a low-voltage current-reuse chopper-stabilized frontend amplifier for fetal ECG monitoring. The proposed amplifier allows for individual tuning of the noise in each measurement channel, minimizing the total power consumption while satisfying all application requirements. The low-voltage current reuse topology exploits power optimization in both the current and the voltage domain, exploiting multiple supply voltages (0.3, 0.6 and 1.2 V). The power management circuitry providing the different supplies is optimized for high efficiency (peak charge-pump efficiency = 90%).The low-voltage amplifier together with its power management circuitry is implemented in a standard 0.18 μm CMOS process and characterized experimentally. The amplifier core achieves both good noise efficiency factor (NEF=1.74) and power efficiency factor (PEF=1.05). Experiments show that the amplifier core can provide a noise level of 0.34 μVrms in a 0.7 to 182 Hz band, consuming 1.17 μW power. The amplifier together with its power management circuitry consumes 1.56 μW, achieving a PEF of 1.41. The amplifier is also validated with adult ECG and pre-recorded fetal ECG measurements.

A Bidirectional Neural Interface IC with Chopper Stabilized BioADC Array and Charge Balanced Stimulator

PubMed Central

Greenwald, Elliot; So, Ernest; Wang, Qihong; Mollazadeh, Mohsen; Maier, Christoph; Etienne-Cummings, Ralph; Cauwenberghs, Gert; Thakor, Nitish

2016-01-01

We present a bidirectional neural interface with a 4-channel biopotential analog-to-digital converter (bioADC) and a 4-channel current-mode stimulator in 180nm CMOS. The bioADC directly transduces microvolt biopotentials into a digital representation without a voltage-amplification stage. Each bioADC channel comprises a continuous-time first-order ΔΣ modulator with a chopper-stabilized OTA input and current feedback, followed by a second-order comb-filter decimator with programmable oversampling ratio. Each stimulator channel contains two independent digital-to-analog converters for anodic and cathodic current generation. A shared calibration circuit matches the amplitude of the anodic and cathodic currents for charge balancing. Powered from a 1.5V supply, the analog and digital circuits in each recording channel draw on average 1.54 μA and 2.13 μA of supply current, respectively. The bioADCs achieve an SNR of 58 dB and a SFDR of >70 dB, for better than 9-b ENOB. Intracranial EEG recordings from an anesthetized rat are shown and compared to simultaneous recordings from a commercial reference system to validate performance in-vivo. Additionally, we demonstrate bidirectional operation by recording cardiac modulation induced through vagus nerve stimulation, and closed-loop control of cardiac rhythm. The micropower operation, direct digital readout, and integration of electrical stimulation circuits make this interface ideally suited for closed-loop neuromodulation applications. PMID:27845676

Straight and chopped dc performance data for a General Electric 5BT 2366C10 motor and an EV-1 controller

NASA Technical Reports Server (NTRS)

Edie, P. C.

1981-01-01

Performance data on the General Electric 5BT 2366C10 series wound dc motor and EV-1 Chopper Controller is supplied for the electric vehicle manufacturer. Data is provided for both straight and chopped dc input to the motor, at 2 motor temperature levels. Testing was done at 6 voltage increments to the motor, and 2 voltage increments to the controller. Data results are presented in both tabular and graphical forms. Tabular information includes motor voltage and current input data, motor speed and torque output data, power data and temperature data. Graphical information includes torque-speed, motor power output-speed, torque-current, and efficiency-speed plots under the various operating conditions. The data resulting from this testing shows the speed-torque plots to have the most variance with operating temperature. The maximum motor efficiency is between 86% and 87%, regardless of temperature or mode of operation. When the chopper is utilized, maximum motor efficiency occurs when the chopper duty cycle approaches 100%.

Chiral detection in high-performance liquid chromatography by vibrational circular dichroism.

PubMed

Tran, C D; Grishko, V I; Huang, G

1994-09-01

A novel chiral detector for high-performance liquid chromatography has been developed. This detector is based on the measurement of circular dichroism of chiral effluents in the infrared region, i.e., vibrational circular dichroism (VCD). In this instrument, a solid-state spectral tunable (from 2.4 to 3.5 microns) F-center laser was used as the light source. The linearly polarized laser beam was converted into left circularly polarized light (LCPL) and right circularly polarized light (RCPL) at 42 kHz by means of a photoelastic modulator. The intensity of the LCPL and RCPL transmitted through the sample was measured by a liquid nitrogen cooled indium antimonide detector. Double modulation was employed to reduce the noise associated with the laser beam. Specifically, the linearly polarized laser beam, prior to being converted to CPL, was modulated at 85 Hz by a mechanical chopper. Demodulation and amplification were accomplished with the use of two lock-in amplifiers. In its present configuration, the instrument can be used to measure the VCD of O-H groups. Its sensitivity is so high that it was able, for the first time, to detect chirally (with limits of detection of micrograms) (R)- and (S)-2,2,2-trifluoro-1-(9- anthryl)ethanol and (R)- and (S)-benzoin when these compounds were chromatographically separated from the corresponding racemic mixtures by a Chiralcel-OD column. The main advantage of this chiral detector is, however, its universality; i.e., it can be used to virtually detect any chiral compounds which has O-H group (e.g, aliphatic alcohols such as 2-octanol).

Simple method enabling pulse on command from high power, high frequency lasers

NASA Astrophysics Data System (ADS)

Baer, David J.; Marshall, Graham D.; Coutts, David W.; Mildren, Richard P.; Withford, Michael J.

2006-09-01

A method for addressing individual laser pulses in high repetition frequency systems using an intracavity optical chopper and novel electronic timing system is reported. This "pulse on command" capability is shown to enable free running and both subharmonic pulse rate and burst mode operation of a high power, high pulse frequency copper vapor laser while maintaining a fixed output pulse energy. We demonstrate that this technique can be used to improve feature finish when laser micromachining metal.

High-speed electromechanical chutter for imaging spectrographs

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet (Inventor)

2005-01-01

The present invention presents a high-speed electromechanical shutter which has at least two rotary beam choppers that are synchronized using a phase-locked loop electronic control to reduce the duty cycle. These choppers have blade means that can comprise discs or drums, each having about 60 (+/- 15) slots which are from about 0.3 to about 0.8 mm wide and about 5 to about 20 nun long (radially) which are evenly distributed through out 360 deg, and a third rotary chopper which is optically aligned has a small number of slots, such as for example, 1 to 10 slots which are about 1 to about 2 mm wide and about 5 to about 20 mm long (radially). Further the blade means include phase slots that allow the blade means to be phase locked using a closed loop control circuit. In addition, in a preferred embodiment, the system also has a leaf shutter. Thus the invention preferably achieves a gate width of less than about 100 microseconds, using motors that operate at 3000 to 10,OOO rpm, and with a phase jitter of less than about 1.5 microseconds, and further using an aperture with more than about 75% optical transmission with a clear aperture of about 0.8 -10 nun. The system can be synchronized to external sources at 0 6 kHz lasers, data acquisition systems, and cameras.

High-speed electromechanical shutter for imaging spectrographs

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet (Inventor)

2005-01-01

The present invention presents a high-speed electromechanical shutter which has at least two rotary beam choppers that are synchronized using a phase-locked loop electronic control to reduce the duty cycle. These choppers have blade means that can comprise discs or drums, each having about 60 (+/-15) slots which are from about 0.3 to about 0.8 mm wide and about 5 to about 20 mm long (radially) which are evenly distributed through out 360?, and a third rotary chopper which is optically aligned has a small number of slots, such as for example, 1 to 10 slots which are about 1 to about 2 mm wide and about 5 to about 20 mm long (radially). Further the blade means include phase slots that allow the blade means to be phase locked using a closed loop control circuit. In addition, in a preferred embodiment, the system also has a leaf shutter. Thus the invention preferably achieves a gate width of less than about 100 microseconds, using motors that operate at 3000 to 10,000 rpm, and with a phase jitter of less than about 1.5 microseconds, and further using an aperture with more than about 75% optical transmission with a clear aperture of about 0.8 mm?10 mm. The system can be synchronized to external sources at 0 6 kHz lasers, data acquisition systems, and cameras.

An electric vehicle propulsion system's impact on battery performance: An overview

NASA Technical Reports Server (NTRS)

Bozek, J. M.; Smithrick, J. J.; Cataldo, R. C.; Ewashinka, J. G.

1980-01-01

The performance of two types of batteries, lead-acid and nickel-zinc, was measured as a function of the charging and discharging demands anticipated from electric vehicle propulsion systems. The benefits of rapid high current charging were mixed: although it allowed quick charges, the energy efficiency was reduced. For low power (overnight) charging the current wave shapes delivered by the charger to the battery tended to have no effect on the battery cycle life. The use of chopper speed controllers with series traction motors resulted in a significant reduction in the energy available from a battery whenever the motor operates at part load. The demand placed on a battery by an electric vehicle propulsion system containing electrical regenerative braking confirmed significant improvment in short term performance of the battery.

Correlation spectrometer for filtering of (quasi) elastic neutron scattering with variable resolution

NASA Astrophysics Data System (ADS)

Magazù, Salvatore; Mezei, Ferenc; Migliardo, Federica

2018-05-01

In a variety of applications of inelastic neutron scattering spectroscopy the goal is to single out the elastic scattering contribution from the total scattered spectrum as a function of momentum transfer and sample environment parameters. The elastic part of the spectrum is defined in such a case by the energy resolution of the spectrometer. Variable elastic energy resolution offers a way to distinguish between elastic and quasi-elastic intensities. Correlation spectroscopy lends itself as an efficient, high intensity approach for accomplishing this both at continuous and pulsed neutron sources. On the one hand, in beam modulation methods the Liouville theorem coupling between intensity and resolution is relaxed and time-of-flight velocity analysis of the neutron velocity distribution can be performed with 50 % duty factor exposure for all available resolutions. On the other hand, the (quasi)elastic part of the spectrum generally contains the major part of the integrated intensity at a given detector, and thus correlation spectroscopy can be applied with most favorable signal to statistical noise ratio. The novel spectrometer CORELLI at SNS is an example for this type of application of the correlation technique at a pulsed source. On a continuous neutron source a statistical chopper can be used for quasi-random time dependent beam modulation and the total time-of-flight of the neutron from the statistical chopper to detection is determined by the analysis of the correlation between the temporal fluctuation of the neutron detection rate and the statistical chopper beam modulation pattern. The correlation analysis can either be used for the determination of the incoming neutron velocity or for the scattered neutron velocity, depending of the position of the statistical chopper along the neutron trajectory. These two options are considered together with an evaluation of spectrometer performance compared to conventional spectroscopy, in particular for variable

Laser synchronized high-speed shutter for spectroscopic application

DOEpatents

Miles, Paul C.; Porter, Eldon L.; Prast, Thomas L.; Sunnarborg, Duane A.

2002-01-01

A fast mechanical shutter, based on rotating chopper wheels, has been designed and implemented to shutter the entrance slit of a spectrograph. This device enables an exposure time of 9 .mu.s to be achieved for a 0.8 mm wide spectrograph entrance slit, achieves 100% transmission in the open state, and an essentially infinite extinction ratio. The device further incorporates chopper wheel position sensing electronics to permit the synchronous triggering of a laser source.

The high-resolution time-of-flight spectrometer TOFTOF

NASA Astrophysics Data System (ADS)

Unruh, Tobias; Neuhaus, Jürgen; Petry, Winfried

2007-10-01

The TOFTOF spectrometer is a multi-disc chopper time-of-flight spectrometer for cold neutrons at the research neutron source Heinz Maier-Leibnitz (FRM II). After five reactor cycles of routine operation the characteristics of the instrument are reported in this article. The spectrometer features an excellent signal to background ratio due to its remote position in the neutron guide hall, an elaborated shielding concept and an s-shaped curved primary neutron guide which acts i.a. as a neutron velocity filter. The spectrometer is fed with neutrons from the undermoderated cold neutron source of the FRM II leading to a total neutron flux of ˜1010n/cm2/s in the continuous white beam at the sample position distributed over a continuous and particularly broad wavelength spectrum. A high energy resolution is achieved by the use of high speed chopper discs made of carbon-fiber-reinforced plastic. In the combination of intensity, resolution and signal to background ratio the spectrometer offers new scientific prospects in the fields of inelastic and quasielastic neutron scattering.

Research on power equalization using a low-loss DC-DC chopper for lithium-ion batteries in electric vehicle

NASA Astrophysics Data System (ADS)

Wei, Y. W.; Liu, G. T.; Xiong, S. N.; Cheng, J. Z.; Huang, Y. H.

2017-01-01

In the near future, electric vehicle is entirely possible to replace traditional cars due to its zero pollution, small power consumption and low noise. Lithium-ion battery, which owns lots of advantages such as lighter and larger capacity and longer life, has been widely equipped in different electric cars all over the world. One disadvantage of this energy storage device is state of charge (SOC) difference among these cells in each series branch. If equalization circuit is not allocated for series-connected batteries, its safety and lifetime are declined due to over-charge or over-discharge happened, unavoidably. In this paper, a novel modularized equalization circuit, based on DC-DC chopper, is proposed to supply zero loss in theory. The proposed circuit works as an equalizer when Lithium-ion battery pack is charging or discharging or standing idle. Theoretical analysis and control method have been finished, respectively. Simulation and small scale experiments are applied to verify its real effect.

A high efficiency 3 kW switchmode battery charger

NASA Technical Reports Server (NTRS)

Latos, T. S.; Bosack, D. J.

1982-01-01

This paper discusses the design approach and status of a high-efficiency switchmode battery charger designed to charge a 108 V battery from the 115 Vac line. The charger contains a transformer isolated boost chopper operating at 20 kHz. The boost inductor current is programmed to follow the ac line voltage such that high power factor operation and low line distortion are obtained.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Hao, E-mail: hc000211@ohio.edu; Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701; Cummings, Marvin

High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beammore » attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Hao; Cummings, Marvin L.; Shirato, Nozomi

High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the requiredmore » beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.« less

Principles for timing at spallation neutron sources based on developments at LANSCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, R. O.; Merl, R. B.; Rose, C. R.

2001-01-01

Due to AC-power-grid frequency fluctuations, the designers for accelerator-based spallation-neutron facilities have worked to optimize the conflicting demands of accelerator and neutron chopper performance. For the first time, we are able to quantitatively access the tradeoffs between these two constraints and design or upgrade a facility to optimize total system performance using powerful new simulation techniques. We have modeled timing systems that integrate chopper controllers and chopper hardware and built new systems. Thus, at LANSCE, we now operate multiple chopper systems and the accelerator as simple slaves to a single master-timing-reference generator. Based on this experience we recommend that spallationmore » neutron sources adhere to three principles. First, timing for pulsed sources should be planned starting with extraction at a fixed phase and working backwards toward the leading edge of the beam pulse. Second, accelerator triggers and storage ring extraction commands from neutron choppers offer only marginal benefits to accelerator-based spallation sources. Third, the storage-ring RF should be phase synchronized with neutron choppers to provide extraction without the one orbit timing uncertainty.« less

100-kHz shot-to-shot broadband data acquisition for high-repetition-rate pump-probe spectroscopy.

PubMed

Kanal, Florian; Keiber, Sabine; Eck, Reiner; Brixner, Tobias

2014-07-14

Shot-to-shot broadband detection is common in ultrafast pump-probe spectroscopy. Taking advantage of the intensity correlation of subsequent laser pulses improves the signal-to-noise ratio. Finite data readout times of CCD chips in the employed spectrometer and the maximum available speed of mechanical pump-beam choppers typically limit this approach to lasers with repetition rates of a few kHz. For high-repetition (≥ 100 kHz) systems, one typically averages over a larger number of laser shots leading to inferior signal-to-noise ratios or longer measurement times. Here we demonstrate broadband shot-to-shot detection in transient absorption spectroscopy with a 100-kHz femtosecond laser system. This is made possible using a home-built high-speed chopper with external laser synchronization and a fast CCD line camera. Shot-to-shot detection can reduce the data acquisition time by two orders of magnitude compared to few-kHz lasers while keeping the same signal-to-noise ratio.

Inductive Interference in Rapid Transit Signaling Systems. Volume 1. Theory and Background.

DOT National Transportation Integrated Search

1986-05-01

This report describes the mechanism of inductive interference to audio frequency (AF) signaling systems used in rail transit operations, caused by rail transit vehicles with chopper propulsion control. Choppers are switching circuits composed of high...

A 600 VOLT MULTI-STAGE, HIGH REPETITION RATE GAN FET SWITCH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frolov, D.; Pfeffer, H.; Saewert, G.

Using recently available GaN FETs, a 600 Volt three- stage, multi-FET switch has been developed having 2 nanosecond rise time driving a 200 Ohm load with the potential of approaching 30 MHz average switching rates. Possible applications include driving particle beam choppers kicking bunch-by-bunch and beam deflectors where the rise time needs to be custom tailored. This paper reports on the engineering issues addressed, the design approach taken and some performance results of this switch.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salvador Palau, A.; Eder, S. D., E-mail: sabrina.eder@uib.no; Kaltenbacher, T.

Time-of-flight (TOF) is a standard experimental technique for determining, among others, the speed ratio S (velocity spread) of a molecular beam. The speed ratio is a measure for the monochromaticity of the beam and an accurate determination of S is crucial for various applications, for example, for characterising chromatic aberrations in focussing experiments related to helium microscopy or for precise measurements of surface phonons and surface structures in molecular beam scattering experiments. For both of these applications, it is desirable to have as high a speed ratio as possible. Molecular beam TOF measurements are typically performed by chopping the beammore » using a rotating chopper with one or more slit openings. The TOF spectra are evaluated using a standard deconvolution method. However, for higher speed ratios, this method is very sensitive to errors related to the determination of the slit width and the beam diameter. The exact sensitivity depends on the beam diameter, the number of slits, the chopper radius, and the chopper rotation frequency. We present a modified method suitable for the evaluation of TOF measurements of high speed ratio beams. The modified method is based on a systematic variation of the chopper convolution parameters so that a set of independent measurements that can be fitted with an appropriate function are obtained. We show that with this modified method, it is possible to reduce the error by typically one order of magnitude compared to the standard method.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Hoy, Blake W

The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) provides variable energy neutrons for a variety of experiments. The neutrons proceed down beam lines to the experiment hall, which houses a variety of experiments and test articles. Each beam line has one or more neutron choppers which filter the neutron beam based on the neutron energy by using a rotating neutron absorbing material passing through the neutron beam. Excessive vibration of the Vision beam line, believed to be caused by the T0 chopper, prevented the Vision beam line from operating at full capacity. This problem had beenmore » addressed several times by rebalancing/reworking the T0 beam chopper but the problem stubbornly persisted. To determine the cause of the high vibration, dynamic testing was performed. Twenty-seven accelerometer and motor current channels of data were collected during drive up, drive down, coast down, and steady-state conditions; resonance testing and motor current signature analysis were also performed. The data was analyzed for traditional mechanical/machinery issues such as misalignment and imbalance using time series analysis, frequency domain analysis, and operating deflection shape analysis. The analysis showed that the chopper base plate was experiencing an amplified response to the excitation provided by the T0 beam chopper. The amplified response was diagnosed to be caused by higher than expected base plate flexibility, possibly due to improper grouting or loose floor anchors. Based on this diagnosis, a decision was made to dismantle the beam line chopper and remount the base plate. Neutron activation of the beam line components make modifications to the beam line especially expensive and time consuming due to the radiation handling requirements, so this decision had significant financial and schedule implications. It was found that the base plate was indeed loose because of improper grouting during its initial installation. The base plate

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…

Summary of electric vehicle dc motor-controller tests

NASA Technical Reports Server (NTRS)

Mcbrien, E. F.; Tryon, H. B.

1982-01-01

The differences in the performance of dc motors are evaluated when operating with chopper type controllers, and when operating on direct current. The interactions between the motor and the controller which cause these differences are investigated. Motor-controlled tests provided some of the data the quantified motor efficiency variations for both ripple free and chopper modes of operation.

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.

Evolution of Automotive Chopper Circuits Towards Ultra High Efficiency and Power Density

NASA Astrophysics Data System (ADS)

Pavlovsky, Martin; Tsuruta, Yukinori; Kawamura, Atsuo

Automotive industry is considered to be one of the main contributors to environmental pollution and global warming. Therefore, many car manufacturers are in near future planning to introduce hybrid electric vehicles (HEV), fuel cell electric vehicles (FCEV) and pure electric vehicles (EV) to make our cars more environmentally friendly. These new vehicles require highly efficient and small power converters. In recent years, considerable improvements were made in designing such converters. In this paper, an approach based on so called Snubber Assisted Zero Voltage and Zero Current Switching topology otherwise also known as SAZZ is presented. This topology has evolved to be one of the leaders in the field of highly efficient converters with high power densities. Evolution and main features of this topology are briefly discussed. Capabilities of the topology are demonstrated on two case study prototypes based on different design approaches. The prototypes are designed to be fully bi-directional for peak power output of 30kW. Both designs reached efficiencies close to 99% in wide load range. Power densities over 40kW/litre are attainable in the same time. Combination of MOSFET technology and SAZZ topology is shown to be very beneficial to converters designed for EV applications.

Implementation of cross correlation for energy discrimination on the time-of-flight spectrometer CORELLI.

PubMed

Ye, Feng; Liu, Yaohua; Whitfield, Ross; Osborn, Ray; Rosenkranz, Stephan

2018-04-01

The CORELLI instrument at Oak Ridge National Laboratory is a statistical chopper spectrometer designed and optimized to probe complex disorder in crystalline materials through diffuse scattering experiments. On CORELLI, the high efficiency of white-beam Laue diffraction combined with elastic discrimination have enabled an unprecedented data collection rate to obtain both the total and the elastic-only scattering over a large volume of reciprocal space from a single measurement. To achieve this, CORELLI is equipped with a statistical chopper to modulate the incoming neutron beam quasi-randomly, and then the cross-correlation method is applied to reconstruct the elastic component from the scattering data. Details of the implementation of the cross-correlation method on CORELLI are given and its performance is discussed.

Straight and chopped DC performance data for a reliance EV-250AT motor with a General Electric EV-1 controller

NASA Technical Reports Server (NTRS)

Edie, P. C.

1981-01-01

Straight and chopped DC motor performances for a Reliance EV-250AT motor with an EV-1 controller were examined. Effects of motor temperature and operating voltage are shown. It is found that the maximum motor efficiency is approximately 85% at low operating temperatures in the straight DC mode. Chopper efficiency is 95% under all operating conditions. For equal speeds, the motor operated in the chopped mode develops slightly more torque and draws more current than it does in the straight DC mode.

SOFIA's secondary mirror assembly: in-flight performance and control approach

NASA Astrophysics Data System (ADS)

Reinacher, Andreas; Lammen, Yannick; Roeser, Hans-Peter

2016-08-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5m infrared telescope built into a Boeing 747 SP. In 2014 SOFIA reached its Full Operational Capability milestone and nowadays takes off about three times a week to observe the infrared sky from altitudes above most of the atmosphere's water vapor content. An actively controlled 352mm SiC secondary mirror is used for infrared chopping with peak-to-peak amplitudes of up to 10 arcmin and chop frequencies of up to 20Hz and also as actuator for fast pointing corrections. The Swiss-made Secondary Mirror Mechanism (SMM) is a complex, highly integrated and compact flexure based mechanism that has been performing with remarkable reliability during recent years. Above mentioned capabilities are provided by the Tilt Chopper Mechanism (TCM) which is one of the two stages of the SMM. In addition the SMM is also used to establish a collimated telescope and to adjust the telescope focus depending on the structure's temperature which ranges from about 40°C at takeoff in Palmdale, CA to about -40°C in the stratosphere. This is achieved with the Focus Center Mechanism (FCM) which is the base stage of the SMM on which the TCM is situated. Initially the TCM was affected by strong vibrations at about 300 Hz which led to unacceptable image smearing. After some adjustments to the PID-type controller it was finally decided to develop a completely new control algorithm in state space. This pole placement controller matches the closed loop system poles to those of a Bessel filter with a corner frequency of 120 Hz for optimal square wave behavior. To reduce noise present on the position and current sensors and to estimate the velocity a static gain Kalman Filter was designed and implemented. A system inherent delay is incorporated in the Kalman filter design and measures were applied to counteract the actuators' hysteresis. For better performance over the full operational temperature range and to represent an amplitude

Advances in Neutron Spectroscopy and High Magnetic Field Instrumentation for studies of Correlated Electron Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granroth, Garrett E

2011-01-01

Neutron Spectroscopy has provided critical information on the magnetism in correlated electron systems. Specifically quantum magnets, superconductors, and multi-ferroics are areas of productive research. A discussion of recent measurements on the SEQUOIA spectrometer will provide examples of how novel instrumentation concepts are used on the latest generation of spectrometers to extend our knowledge in such systems. The now ubiquitous function of sample rotation allows for full mapping of volumes ofmore » $Q$ and $$\\omega$$ space. An instrument focused on low angles could extend these maps to cover more of the first Brillioun zone. Innovative chopper cascades allow two unique modes of operation. Multiplexed measurements allow the simultaneous measurement of high and low energy features in an excitation spectrum. Alternatively by limiting the neutron bandwidth incident on the Fermi Chopper, background from subsequent time frames is removed, enabling the observation of weak, large energy transfer features. Finally the implementation of event-based detection for neutron experiments is time correlated experiments. Diffraction studies of the high field spin states in MnWO$$_4$$ using magnetic fields up to 30 T, provided by a pulsed magnet, illustrate this method. Expanding the high field studies to spectroscopy will require a novel instrument, focused around a world class DC magnet, like Zeemans proposed for the SNS.« less

Implementation of cross correlation for energy discrimination on the time-of-flight spectrometer CORELLI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Feng; Liu, Yaohua; Whitfield, Ross

The CORELLI instrument at Oak Ridge National Laboratory is a statistical chopper spectrometer designed and optimized to probe complex disorder in crystalline materials through diffuse scattering experiments. On CORELLI, the high efficiency of white-beam Laue diffraction combined with elastic discrimination have enabled an unprecedented data collection rate to obtain both the total and the elastic-only scattering over a large volume of reciprocal space from a single measurement. To achieve this, CORELLI is equipped with a statistical chopper to modulate the incoming neutron beam quasi-randomly, and then the cross-correlation method is applied to reconstruct the elastic component from the scattering data.more » Lastly, details of the implementation of the cross-correlation method on CORELLI are given and its performance is discussed.« less

Implementation of cross correlation for energy discrimination on the time-of-flight spectrometer CORELLI

DOE PAGES

Ye, Feng; Liu, Yaohua; Whitfield, Ross; ...

2018-03-26

The CORELLI instrument at Oak Ridge National Laboratory is a statistical chopper spectrometer designed and optimized to probe complex disorder in crystalline materials through diffuse scattering experiments. On CORELLI, the high efficiency of white-beam Laue diffraction combined with elastic discrimination have enabled an unprecedented data collection rate to obtain both the total and the elastic-only scattering over a large volume of reciprocal space from a single measurement. To achieve this, CORELLI is equipped with a statistical chopper to modulate the incoming neutron beam quasi-randomly, and then the cross-correlation method is applied to reconstruct the elastic component from the scattering data.more » Lastly, details of the implementation of the cross-correlation method on CORELLI are given and its performance is discussed.« less

A clocked high-pass-filter-based offset cancellation technique for high-gain biomedical amplifiers

NASA Astrophysics Data System (ADS)

Pal, Dipankar; Goswami, Manish

2010-05-01

In this article, a simple offset cancellation technique based on a clocked high-pass filter with extremely low output offset is presented. The configuration uses the on-resistance of a complementary metal oxide semiconductor (CMOS) transmission gate (X-gate) and tunes the lower 3-dB cut-off frequency with a matched pair of floating capacitors. The results compare favourably with the more complex auto-zeroing and chopper stabilisation techniques of offset cancellation in terms of power dissipation, component count and bandwidth, while reporting inferior output noise performance. The design is suitable for use in biomedical amplifier systems for applications such as ENG-recording. The system is simulated in Spectre Cadence 5.1.41 using 0.6 μm CMOS technology and the total block gain is ∼83.0 dB while the phase error is <5°. The power consumption is 10.2 mW and the output offset obtained for an input monotone signal of 5 μVpp is 1.28 μV. The input-referred root mean square noise voltage between 1 and 5 kHz is 26.32 nV/√Hz.

High performance concrete bridges

DOT National Transportation Integrated Search

2000-08-01

This compilation of FHWA reports focuses on high performance concrete bridges. High performance concrete is described as concrete with enhanced durability and strength characteristics. Under the Strategic Highway Research Program (SHRP), more than 40...

High performance systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

HIGH RESOLUTION EMITTANCE MEASUREMENTS AT SNS FRONT END

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aleksandrov, Alexander V; Zhukov, Alexander P

2013-01-01

The Spallation Neutron Source (SNS) linac accelerates an H- beam from 2.5MeV up to 1GeV. Recently the emittance scanner in the MEBT (2.5 MeV) was upgraded. In addition to the slit - harp measurement, we now can use a slit installed on the same actuator as the harp. In combination with a faraday cup located downstream in DTL part of the linac, it represents a classical slit-slit emittance measurement device. While a slit slit scan takes much longer, it is immune to harp related problems such as wire cross talk, and thus looks promising for accurate halo measurements. Time resolutionmore » of the new device seems to be sufficient to estimate the amount of beam in the chopper gap (the scanner is downstream of the chopper), and probably to measure its emittance. This paper describes the initial measurements with the new device and some model validation data.« less

High Performance Computing at NASA

NASA Technical Reports Server (NTRS)

Bailey, David H.; Cooper, D. M. (Technical Monitor)

1994-01-01

The speaker will give an overview of high performance computing in the U.S. in general and within NASA in particular, including a description of the recently signed NASA-IBM cooperative agreement. The latest performance figures of various parallel systems on the NAS Parallel Benchmarks will be presented. The speaker was one of the authors of the NAS (National Aerospace Standards) Parallel Benchmarks, which are now widely cited in the industry as a measure of sustained performance on realistic high-end scientific applications. It will be shown that significant progress has been made by the highly parallel supercomputer industry during the past year or so, with several new systems, based on high-performance RISC processors, that now deliver superior performance per dollar compared to conventional supercomputers. Various pitfalls in reporting performance will be discussed. The speaker will then conclude by assessing the general state of the high performance computing field.

PN-CCD camera for XMM: performance of high time resolution/bright source operating modes

NASA Astrophysics Data System (ADS)

Kendziorra, Eckhard; Bihler, Edgar; Grubmiller, Willy; Kretschmar, Baerbel; Kuster, Markus; Pflueger, Bernhard; Staubert, Ruediger; Braeuninger, Heinrich W.; Briel, Ulrich G.; Meidinger, Norbert; Pfeffermann, Elmar; Reppin, Claus; Stoetter, Diana; Strueder, Lothar; Holl, Peter; Kemmer, Josef; Soltau, Heike; von Zanthier, Christoph

1997-10-01

The pn-CCD camera is developed as one of the focal plane instruments for the European photon imaging camera (EPIC) on board the x-ray multi mirror (XMM) mission to be launched in 1999. The detector consists of four quadrants of three pn-CCDs each, which are integrated on one silicon wafer. Each CCD has 200 by 64 pixels (150 micrometer by 150 micrometers) with 280 micrometers depletion depth. One CCD of a quadrant is read out at a time, while the four quadrants can be processed independently of each other. In standard imaging mode the CCDs are read out sequentially every 70 ms. Observations of point sources brighter than 1 mCrab will be effected by photon pile- up. However, special operating modes can be used to observe bright sources up to 150 mCrab in timing mode with 30 microseconds time resolution and very bright sources up to several crab in burst mode with 7 microseconds time resolution. We have tested one quadrant of the EPIC pn-CCD camera at line energies from 0.52 keV to 17.4 keV at the long beam test facility Panter in the focus of the qualification mirror module for XMM. In order to test the time resolution of the system, a mechanical chopper was used to periodically modulate the beam intensity. Pulse periods down to 0.7 ms were generated. This paper describes the performance of the pn-CCD detector in timing and burst readout modes with special emphasis on energy and time resolution.

Tough high performance composite matrix

NASA Technical Reports Server (NTRS)

Pater, Ruth H. (Inventor); Johnston, Norman J. (Inventor)

1994-01-01

This invention is a semi-interpentrating polymer network which includes a high performance thermosetting polyimide having a nadic end group acting as a crosslinking site and a high performance linear thermoplastic polyimide. Provided is an improved high temperature matrix resin which is capable of performing in the 200 to 300 C range. This resin has significantly improved toughness and microcracking resistance, excellent processability, mechanical performance, and moisture and solvent resistances.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aeloiza, Eddy C.; Burgos, Rolando P.

A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured tomore » pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Awida, Mohamed; Chen, Alex; Khabiboulline, Timergali

High intensity proton particle accelerators that supports several simultaneous physics experiments requires sharing the beam. A bunch by bunch beam chopper system located after the Radio Frequency Quadrupole (RFQ) is required in this case to structure the beam in the proper bunch format required by the several experiments. The unused beam will need to be kicked out of the beam path and is disposed in a beam dumb. In this paper, we report on the RF modeling results of a proposed helical kicker. Two beam kickers constitutes the proposed chopper. The beam sequence is formed by kicking in or outmore » the beam bunches from the streamline. The chopper was developed for Project X Injection Experiment (PXIE).« less

Process analytical technology (PAT) approach to the formulation of thermosensitive protein-loaded pellets: Multi-point monitoring of temperature in a high-shear pelletization.

PubMed

Kristó, Katalin; Kovács, Orsolya; Kelemen, András; Lajkó, Ferenc; Klivényi, Gábor; Jancsik, Béla; Pintye-Hódi, Klára; Regdon, Géza

2016-12-01

In the literature there are some publications about the effect of impeller and chopper speeds on product parameters. However, there is no information about the effect of temperature. Therefore our main aim was the investigation of elevated temperature and temperature distribution during pelletization in a high shear granulator according to process analytical technology. During our experimental work, pellets containing pepsin were formulated with a high-shear granulator. A specially designed chamber (Opulus Ltd.) was used for pelletization. This chamber contained four PyroButton-TH® sensors built in the wall and three PyroDiff® sensors 1, 2 and 3cm from the wall. The sensors were located in three different heights. The impeller and chopper speeds were set on the basis of 3 2 factorial design. The temperature was measured continuously in 7 different points during pelletization and the results were compared with the temperature values measured by the thermal sensor of the high-shear granulator. The optimization parameters were enzyme activity, average size, breaking hardness, surface free energy and aspect ratio. One of the novelties was the application of the specially designed chamber (Opulus Ltd.) for monitoring the temperature continuously in 7 different points during high-shear granulation. The other novelty of this study was the evaluation of the effect of temperature on the properties of pellets containing protein during high-shear pelletization. Copyright © 2016 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adachi, T.; The Graduate University for Advanced Studies, Hayama, Miura, Kanagawa 240-0193; Arai, T.

A new type of pulse chopper called an Einzel lens chopper is described. An Einzel lens placed immediately after an electron cyclotron resonance ion source is driven by high-voltage pulses generated by a newly developed solid-state Marx generator. A rectangular negative barrier pulse-voltage is controlled in time, and the barrier pulse is turned on only when a beam pulse is required. The results of successful experiments are reported herein.

Straight and chopped DC performance data for a General Electric 5BY436A1 DC shunt motor with a General Electric EV-1 controller

NASA Technical Reports Server (NTRS)

Edie, P. C.

1981-01-01

Both straight and chopped dc motor performance data for a General Electric 5BY436A1 motor with a General Electric EV-1 controller is presented in tabular and graphical formats. Effects of motor temperature and operating voltage are also shown. The maximum motor efficiency is approximately 85% at low operating temperatures in the straight dc mode. Chopper efficiency can be assumed to be 95% under all operating conditions. For equal speeds, the motor operated in the chopped mode develops slightly more torque and draws more current than it does in the straight mode.

High-Performance Thermoelectric Semiconductors

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre; Caillat, Thierry; Borshchevsky, Alexander

1994-01-01

Figures of merit almost double current state-of-art thermoelectric materials. IrSb3 is semiconductor found to exhibit exceptional thermoelectric properties. CoSb3 and RhSb3 have same skutterudite crystallographic structure as IrSb3, and exhibit exceptional transport properties expected to contribute to high thermoelectric performance. These three compounds form solid solutions. Combination of properties offers potential for development of new high-performance thermoelectric materials for more efficient thermoelectric power generators, coolers, and detectors.

SOFIA pointing and chopping: performance and prospect

NASA Astrophysics Data System (ADS)

Reinacher, Andreas; Lammen, Yannick; Graf, Friederike; Jakob, Holger

2016-09-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5m infrared telescope built into a Boeing 747 SP. In 2014 SOFIA reached its Full Operational Capability milestone and nowadays takes off about three times a week to observe the infrared sky from altitudes above most of the atmosphere's water vapor content. Despite reaching this major milestone the work to improve the observatory's performance is continuing in many areas. This paper focuses on the telescope's current pointing and chopping performance and gives an overview over the ongoing and foreseen work to further improve in those two areas. Pointing performance as measured with the fast focal plane camera in flight is presented and based on that data it is elaborated how and in which frequency bands a further reduction of image jitter might be achieved. One contributor to the remaining jitter as well as the major actuator to reduce jitter with frequencies greater than 5 Hz is SOFIA's Secondary Mirror Assembly (SMA) or Chopper. As-is SMA jitter and chopping performance data as measured in flight is presented as well as recent improvements to the position sensor cabling and calibration and their effect on the SMA's pointing accuracy. Furthermore a brief description of a laboratory mockup of the SMA is given and the intended use of this mockup to test major hardware changes for further performance improvement is explained.

A Neutron Diffractometer for a Long Pulsed Neutron Source

NASA Astrophysics Data System (ADS)

Sokol, Paul; Wang, Cailin

Long pulsed neutron sources are being actively developed as small university based sources and are being considered for the next generation of high powered sources, such as the European Neutron Source (ESS) and the Spallation Neutron Source (SNS) second target station. New instrumentation concepts will be required to effectively utilize the full spectrum of neutrons generated by these sources. Neutron diffractometers, which utilize time-of-flight (TOF) techniques for wavelength resolution, are particularly problematic. We describe an instrument for a long pulsed source that provides resolution comparable to that obtained on short pulsed sources without the need of long incident flight paths. We accomplish this by utilizing high speed choppers to impose a time structure on the spectrum of incident neutrons. By strategically positioning these choppers the response matrix assumes a convenient form that can be deconvoluted from the measured TOF spectrum to produce the diffraction pattern of the sample. We compare the performance of this instrument to other possible diffraction instruments that could be utilized on a long pulsed source.

Effects of carbon/graphite fiber contamination on high voltage electrical insulation

NASA Technical Reports Server (NTRS)

Garrity, T.; Eichler, C.

1980-01-01

The contamination mechanics and resulting failure modes of high voltage electrical insulation due to carbon/graphite fibers were examined. The high voltage insulation vulnerability to carbon/graphite fiber induced failure was evaluated using a contamination system which consisted of a fiber chopper, dispersal chamber, a contamination chamber, and air ducts and suction blower. Tests were conducted to evaluate the effects of fiber length, weathering, and wetness on the insulator's resistance to carbon/graphite fibers. The ability of nuclear, fossil, and hydro power generating stations to maintain normal power generation when the surrounding environment is contaminated by an accidental carbon fiber release was investigated. The vulnerability assessment included only the power plant generating equipment and its associated controls, instrumentation, and auxiliary and support systems.

A tough high performance composite matrix

NASA Technical Reports Server (NTRS)

Pater, Ruth H. (Inventor); Johnston, Norman J. (Inventor)

1992-01-01

This invention is a semi-interpenetrating polymer network which includes a high performance thermosetting polyimide having a nadic end group acting as a crosslinking site and a high performance linear thermoplastic polyimide. An improved high temperature matrix resin is provided which is capable of performing in the 200 to 300 C range. This resin has significantly improved toughness and microcracking resistance, excellent processability, mechanical performance and moisture and solvent resistances.

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)

Sofia Observatory Performance and Characterization

NASA Technical Reports Server (NTRS)

Temi, Pasquale; Miller, Walter; Dunham, Edward; McLean, Ian; Wolf, Jurgen; Becklin, Eric; Bida, Tom; Brewster, Rick; Casey, Sean; Collins, Peter;

Pressurized planar electrochromatography, high-performance thin-layer chromatography and high-performance liquid chromatography--comparison of performance.

PubMed

Płocharz, Paweł; Klimek-Turek, Anna; Dzido, Tadeusz H

2010-07-16

Kinetic performance, measured by plate height, of High-Performance Thin-Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Pressurized Planar Electrochromatography (PPEC) was compared for the systems with adsorbent of the HPTLC RP18W plate from Merck as the stationary phase and the mobile phase composed of acetonitrile and buffer solution. The HPLC column was packed with the adsorbent, which was scrapped from the chromatographic plate mentioned. An additional HPLC column was also packed with adsorbent of 5 microm particle diameter, C18 type silica based (LiChrosorb RP-18 from Merck). The dependence of plate height of both HPLC and PPEC separating systems on flow velocity of the mobile phase and on migration distance of the mobile phase in TLC system was presented applying test solute (prednisolone succinate). The highest performance, amongst systems investigated, was obtained for the PPEC system. The separation efficiency of the systems investigated in the paper was additionally confirmed by the separation of test component mixture composed of six hormones. 2010 Elsevier B.V. All rights reserved.

High performance computing and communications program

NASA Technical Reports Server (NTRS)

Holcomb, Lee

1992-01-01

A review of the High Performance Computing and Communications (HPCC) program is provided in vugraph format. The goals and objectives of this federal program are as follows: extend U.S. leadership in high performance computing and computer communications; disseminate the technologies to speed innovation and to serve national goals; and spur gains in industrial competitiveness by making high performance computing integral to design and production.

Architecture of a mixed-mode electrophysiological signal acquisition interface.

PubMed

Shen, Ding-Lan; Chen, Jyun-Min

2012-01-01

This paper proposes mixed-mode architecture for the acquisition interface of electrophysiological signals. The architecture advances the analog-to-digital converter (ADC) from the second chopper signal in the conventional approach and performs the second chopper operation in the digital domain. The demanded low-pass filter (LPF) is realized with a digital type. The analog LPF in feedback path is substituted with a digital one accompanying with a digital-to-analog converter (DAC). The analog variation is decreased due to the digitization of these operations. The entire architecture is simulated with the ECG input in a behavior model of Simulink.

Improved battery charger for electric vehicles

NASA Technical Reports Server (NTRS)

Rippel, W. E.

1981-01-01

Polyphase version of single-phase "boost chopper" significantly reduces ripple and electromagnetic interference (EMI). Drive circuit of n-phase boost chopper incorporates n-phase duty-cycle generator; inductor, transistor, and diode compose chopper which can run on single-phase or three-phase alternating current or on direct current. Device retains compactness and power factors approaching unity, while improving efficiency.

INL High Performance Building Strategy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jennifer D. Morton

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 reflectmore » 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

High-Performance Computing and Visualization | Energy Systems Integration

Science.gov Websites

Facility | NREL High-Performance Computing and Visualization High-Performance Computing and Visualization High-performance computing (HPC) and visualization at NREL propel technology innovation as a . Capabilities High-Performance Computing NREL is home to Peregrine-the largest high-performance computing system

A Practical and Portable Solids-State Electronic Terahertz Imaging System

PubMed Central

Smart, Ken; Du, Jia; Li, Li; Wang, David; Leslie, Keith; Ji, Fan; Li, Xiang Dong; Zeng, Da Zhang

2016-01-01

A practical compact solid-state terahertz imaging system is presented. Various beam guiding architectures were explored and hardware performance assessed to improve its compactness, robustness, multi-functionality and simplicity of operation. The system performance in terms of image resolution, signal-to-noise ratio, the electronic signal modulation versus optical chopper, is evaluated and discussed. The system can be conveniently switched between transmission and reflection mode according to the application. A range of imaging application scenarios was explored and images of high visual quality were obtained in both transmission and reflection mode. PMID:27110791

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…

High Performance, Dependable Multiprocessor

NASA Technical Reports Server (NTRS)

Ramos, Jeremy; Samson, John R.; Troxel, Ian; Subramaniyan, Rajagopal; Jacobs, Adam; Greco, James; Cieslewski, Grzegorz; Curreri, John; Fischer, Michael; Grobelny, Eric;

Probabilistic performance-based design for high performance control systems

NASA Astrophysics Data System (ADS)

Micheli, Laura; Cao, Liang; Gong, Yongqiang; Cancelli, Alessandro; Laflamme, Simon; Alipour, Alice

2017-04-01

High performance control systems (HPCS) are advanced damping systems capable of high damping performance over a wide frequency bandwidth, ideal for mitigation of multi-hazards. They include active, semi-active, and hybrid damping systems. However, HPCS are more expensive than typical passive mitigation systems, rely on power and hardware (e.g., sensors, actuators) to operate, and require maintenance. In this paper, a life cycle cost analysis (LCA) approach is proposed to estimate the economic benefit these systems over the entire life of the structure. The novelty resides in the life cycle cost analysis in the performance based design (PBD) tailored to multi-level wind hazards. This yields a probabilistic performance-based design approach for HPCS. Numerical simulations are conducted on a building located in Boston, MA. LCA are conducted for passive control systems and HPCS, and the concept of controller robustness is demonstrated. Results highlight the promise of the proposed performance-based design procedure.

High performance flexible heat pipes

NASA Technical Reports Server (NTRS)

Shaubach, R. M.; Gernert, N. J.

1985-01-01

A Phase I SBIR NASA program for developing and demonstrating high-performance flexible heat pipes for use in the thermal management of spacecraft is examined. The program combines several technologies such as flexible screen arteries and high-performance circumferential distribution wicks within an envelope which is flexible in the adiabatic heat transport zone. The first six months of work during which the Phase I contract goal were met, are described. Consideration is given to the heat-pipe performance requirements. A preliminary evaluation shows that the power requirement for Phase II of the program is 30.5 kilowatt meters at an operating temperature from 0 to 100 C.

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,…

Long-Wavelength Beam Steerer Based on a Micro-Electromechanical Mirror

PubMed Central

Kos, Anthony B; Gerecht, Eyal

2013-01-01

Commercially available mirrors for scanning long-wavelength beams are too large for high-speed imaging. There is a need for a smaller, more agile pointing apparatus to provide images in seconds, not minutes or hours. A fast long-wavelength beam steerer uses a commercial micro-electro-mechanical system (MEMS) mirror controlled by a high-performance digital signal processor (DSP). The DSP allows high-speed raster scanning of the incident radiation, which is focused to a small waist onto the 9mm2, gold-coated, MEMS mirror surface, while simultaneously acquiring an undistorted, high spatial-resolution image of an object. The beam steerer hardware, software and performance are described. The system can also serve as a miniaturized, high-performance long-wavelength beam chopper for lock-in detection. PMID:26401426

New Synthesis Of High-Performance Bismaleimides

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Lowther, Sharon; Cannon, Michelle; Smith, Janice; Whitely, Karen

1991-01-01

New general synthesis of tough and easy-to-process high-performance bismaleimides (BMI's) developed. Involves reaction of acetylene-terminated compounds with BMI's or biscitraconimides. Offers matrix resins and adhesives having combined advantages of toughness characteristic of thermoplastics and easy processability characteristic of thermosetting materials. Scheme has potential for providing high-performance matrix resins surviving well at high temperatures and absorb little moisture.

High-performance coatings for micromechanical mirrors.

PubMed

Gatto, Alexandre; Yang, Minghong; Kaiser, Norbert; Heber, Jörg; Schmidt, Jan Uwe; Sandner, Thilo; Schenk, Harald; Lakner, Hubert

2006-03-01

High-performance coatings for micromechanical mirrors were developed. The high-reflective metal systems can be integrated into the technology of MOEMS, such as spatial light modulators and microscanning mirrors from the near-infrared down to the vacuum-ultraviolet spectral regions. The reported metal designs permit high optical performances to be merged with suitable mechanical properties and fitting complementary metal-oxide semiconductor compatibility.

Unity power factor switching regulator

NASA Technical Reports Server (NTRS)

Rippel, Wally E. (Inventor)

1983-01-01

A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L.sub.1) and one chopper (Q.sub.1) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180.degree. out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

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.

High-performance conjugate-gradient benchmark: A new metric for ranking high-performance computing systems

DOE PAGES

Dongarra, Jack; Heroux, Michael A.; Luszczek, Piotr

2015-08-17

Here, we describe a new high-performance conjugate-gradient (HPCG) benchmark. HPCG is composed of computations and data-access patterns commonly found in scientific applications. HPCG strives for a better correlation to existing codes from the computational science domain and to be representative of their performance. Furthermore, HPCG is meant to help drive the computer system design and implementation in directions that will better impact future performance improvement.

Dinosaurs can fly -- High performance refining

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 areamore » 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.« less

High performance bilateral telerobot control.

PubMed

Kline-Schoder, Robert; Finger, William; Hogan, Neville

2002-01-01

Telerobotic systems are used when the environment that requires manipulation is not easily accessible to humans, as in space, remote, hazardous, or microscopic applications or to extend the capabilities of an operator by scaling motions and forces. The Creare control algorithm and software is an enabling technology that makes possible guaranteed stability and high performance for force-feedback telerobots. We have developed the necessary theory, structure, and software design required to implement high performance telerobot systems with time delay. This includes controllers for the master and slave manipulators, the manipulator servo levels, the communication link, and impedance shaping modules. We verified the performance using both bench top hardware as well as a commercial microsurgery system.

High-Performance Computing Data Center | Energy Systems Integration

Science.gov Websites

Facility | NREL High-Performance Computing Data Center High-Performance Computing Data Center The Energy Systems Integration Facility's High-Performance Computing Data Center is home to Peregrine -the largest high-performance computing system in the world exclusively dedicated to advancing

Comparative Evaluation of Energy Measurement Models for Transit Systems

DOT National Transportation Integrated Search

1984-02-01

Recent advances in solid state control technology have led to chopper-controlled propulsion systems in urban rail transit applications. Such systems offer the potential for superior train performance through increased train propulsion efficiency and ...

Striving for Excellence Sometimes Hinders High Achievers: Performance-Approach Goals Deplete Arithmetical Performance in Students with High Working Memory Capacity

PubMed Central

Crouzevialle, Marie; Smeding, Annique; Butera, Fabrizio

2015-01-01

We tested whether the goal to attain normative superiority over other students, referred to as performance-approach goals, is particularly distractive for high-Working Memory Capacity (WMC) students—that is, those who are used to being high achievers. Indeed, WMC is positively related to high-order cognitive performance and academic success, a record of success that confers benefits on high-WMC as compared to low-WMC students. We tested whether such benefits may turn out to be a burden under performance-approach goal pursuit. Indeed, for high achievers, aiming to rise above others may represent an opportunity to reaffirm their positive status—a stake susceptible to trigger disruptive outcome concerns that interfere with task processing. Results revealed that with performance-approach goals—as compared to goals with no emphasis on social comparison—the higher the students’ WMC, the lower their performance at a complex arithmetic task (Experiment 1). Crucially, this pattern appeared to be driven by uncertainty regarding the chances to outclass others (Experiment 2). Moreover, an accessibility measure suggested the mediational role played by status-related concerns in the observed disruption of performance. We discuss why high-stake situations can paradoxically lead high-achievers to sub-optimally perform when high-order cognitive performance is at play. PMID:26407097

High-performance IR detector modules

NASA Astrophysics Data System (ADS)

Wendler, Joachim; Cabanski, Wolfgang; Rühlich, Ingo; Ziegler, Johann

2004-02-01

The 3rd generation of infrared (IR) detection modules is expected to provide higher video resolution, advanced functions like multi band or multi color capability, higher frame rates, and better thermal resolution. AIM has developed staring and linear high performance focal plane arrays (FPA) integrated into detector/dewar cooler assemblies (IDCA). Linear FPA"s support high resolution formats such as 1920 x 1152 (HDTV), 1280 x 960, or 1536 x 1152. Standard format for staring FPA"s is 640 x 512. In this configuration, QEIP devices sensitive in the 8 10 µm band as well as MCT devices sensitive in the 3.4 5.0 µm band are available. A 256 x 256 high speed detection module allows a full frame rate >800 Hz. Especially usability of long wavelength devices in high performance FLIR systems does not only depend on the classical electrooptical performance parameters such as NEDT, detectivity, and response homogeneity, but are mainly characterized by the stability of the correction coefficients used for image correction. The FPA"s are available in suited integrated detector/dewar cooler assemblies. The linear cooling engines are designed for maximum stability of the focal plane temperature, low operating temperatures down to 60K, high MTTF lifetimes of 6000h and above even under high ambient temperature conditions. The IDCA"s are equipped with AIM standard or custom specific command and control electronics (CCE) providing a well defined interface to the system electronics. Video output signals are provided as 14 bit digital data rates up to 80 MHz for the high speed devices.

High performance data transfer

NASA Astrophysics Data System (ADS)

Cottrell, R.; Fang, C.; Hanushevsky, A.; Kreuger, W.; Yang, W.

2017-10-01

The exponentially increasing need for high speed data transfer is driven by big data, and cloud computing together with the needs of data intensive science, High Performance Computing (HPC), defense, the oil and gas industry etc. We report on the Zettar ZX software. This has been developed since 2013 to meet these growing needs by providing high performance data transfer and encryption in a scalable, balanced, easy to deploy and use way while minimizing power and space utilization. In collaboration with several commercial vendors, Proofs of Concept (PoC) consisting of clusters have been put together using off-the- shelf components to test the ZX scalability and ability to balance services using multiple cores, and links. The PoCs are based on SSD flash storage that is managed by a parallel file system. Each cluster occupies 4 rack units. Using the PoCs, between clusters we have achieved almost 200Gbps memory to memory over two 100Gbps links, and 70Gbps parallel file to parallel file with encryption over a 5000 mile 100Gbps link.

Test Excavations at Painted Rock Reservoir: Sites AZ Z:1:7, AZ Z:1:8, and AZ S:16:36.

DTIC Science & Technology

1981-11-01

choppers , two-hand manos, pestles, and possible stone vessels) are described as Hakatayan exclusively or as equally characteristic of Hohokam and...features along the ridge that three to four discrete habitation areas may be represented... While these might have been contemporaneous, it seems equally...produced from a core and the other from a quartzite flake. Choppers . A total of 12 large, unifacially worked choppers was recovered from the two sites

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,…

High Performance Computing Meets Energy Efficiency - Continuum Magazine |

Science.gov Websites

NREL High Performance Computing Meets Energy Efficiency High Performance Computing Meets Energy turbines. Simulation by Patrick J. Moriarty and Matthew J. Churchfield, NREL The new High Performance Computing Data Center at the National Renewable Energy Laboratory (NREL) hosts high-speed, high-volume data

Exploring KM Features of High-Performance Companies

NASA Astrophysics Data System (ADS)

Wu, Wei-Wen

2007-12-01

For reacting to an increasingly rival business environment, many companies emphasize the importance of knowledge management (KM). It is a favorable way to explore and learn KM features of high-performance companies. However, finding out the critical KM features of high-performance companies is a qualitative analysis problem. To handle this kind of problem, the rough set approach is suitable because it is based on data-mining techniques to discover knowledge without rigorous statistical assumptions. Thus, this paper explored KM features of high-performance companies by using the rough set approach. The results show that high-performance companies stress the importance on both tacit and explicit knowledge, and consider that incentives and evaluations are the essentials to implementing KM.

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

Analysis and Application of the Bi-Directional Scatter Distribution Function of Photonic Crystals

DTIC Science & Technology

2009-03-01

and reflected light ..................17 10. A CASI source box, showing the beam path, chopper , scaling photodetector, half-wave plate, and linear...off of a semi-reflective beam chopper , shown in Figure 10. Any variation in the output of the laser is detected by it, and the incident power is...box, showing the beam path, chopper , scaling photodetector, half-wave plate, and linear polarizers. 20 The CASI is not sensitive to ambient light

Water-vapour measurements up to the lower stratosphere — the high power raman lidar at the schneefernerhaus

NASA Astrophysics Data System (ADS)

Klanner, Lisa; Trickl, Thomas; Vogelmann, Hannes

2018-04-01

A high-power Raman lidar system has been developed at the high-altitude research station Schneefernerhaus (Garmisch-Partenkirchen, Germany) at 2675 m, at the side of an existing differential-absorption lidar. It is based on a 180-W single-line XeCl laser and on two Newtonian telescopes (up to 1.5-m-diameter). In this way a vertical range up to more than 20 km and an accuracy level of the order of 10 % can be achieved for a measurement time of 1 h. Temperature measurements have been demonstrated to altitudes up to 54 km with just 1 % of the full 308-nm backscatter signal. Significantly higher altitudes are expected when using a chopper that cuts off the first 10 km or for 353 nm.

Performance of the first structure built with high performance concrete in Virginia.

DOT National Transportation Integrated Search

2001-08-01

This study evaluated the preparation and placement operations, concrete properties, cost-effectiveness, and performance over 5 years of the first bridge containing high performance concrete built by the Virginia Department of Transportation. High per...

Rehabilitation Characteristics in High-Performance Hospitals after Acute Stroke.

PubMed

Sawabe, Masashi; Momosaki, Ryo; Hasebe, Kiyotaka; Sawaguchi, Akira; Kasuga, Seiji; Asanuma, Daichi; Suzuki, Shoya; Miyauchi, Narimi; Abo, Masahiro

2018-05-22

Rehabilitation characteristics in high-performance hospitals after acute stroke are not clarified. This retrospective observational study aimed to clarify the characteristics of high-performance hospitals in acute stroke rehabilitation. Patients with stroke discharged from participating acute hospitals were extracted from the Japan Rehabilitation Database for the period 2006-2015. We found 6855 patients from 14 acute hospitals who were eligible for analysis in this study after applying exclusion criteria. We divided facilities into high-performance hospitals and low-performance hospitals using the median of the Functional Independent Measure efficiency for each hospital. We compared rehabilitation characteristics between high- and low-performance hospitals. High-performance hospitals had significantly shorter length of stay. More patients were discharged to home in the high-performance hospitals compared with low-performance hospitals. Patients in high-performance hospitals received greater amounts of physical, occupational, and speech therapy. Patients in high-performance hospitals engaged in more self-exercise, weekend exercise, and exercise in wards. There was more participation of board-certified physiatrists and social workers in high-performance hospitals. Our data suggested that amount, timing, and type of rehabilitation, and participation of multidisciplinary staff are essential for high performance in acute stroke rehabilitation. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

High performance dielectric materials development

NASA Astrophysics Data System (ADS)

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

1994-09-01

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.

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.

Indoor Air Quality in High Performance Schools

EPA Pesticide Factsheets

High performance schools are facilities that improve the learning environment while saving energy, resources, and money. The key is understanding the lifetime value of high performance schools and effectively managing priorities, time, and budget.

Indoor Air Quality in High Performance Schools

EPA Pesticide Factsheets

2017-02-14

High performance schools are facilities that improve the learning environment while saving energy, resources, and money. The key is understanding the lifetime value of high performance schools and effectively managing priorities, time, and budget.

High-Performance Computing Systems and Operations | Computational Science |

Science.gov Websites

NREL Systems and Operations High-Performance Computing Systems and Operations NREL operates high-performance computing (HPC) systems dedicated to advancing energy efficiency and renewable energy technologies. Capabilities NREL's HPC capabilities include: High-Performance Computing Systems We operate

Noise of High-Performance Aircraft at Afterburner

DTIC Science & Technology

2015-10-07

Naval Research Project Title : Noise of High-Performance Aircraft at Afterburner Principal Investigator Dr. Christopher Tam Department...to 08/14/2015 Noise of High-Performance Aircraft at Afterburner Tam, Christopher Sponsored Research Administratiion Florida State University

Moisture Performance of High-R Wall Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Nay B.; Kochkin, Vladimir

High-performance homes offer improved comfort, lower utility bills, and assured durability. The next generation of building enclosures is a key step toward achieving high-performance goals through decreasing energy load demand and enabling advanced space-conditioning systems. Yet the adoption of high-R enclosures and particularly high-R walls has been a slow-growing trend because mainstream builders are hesitant to make the transition. In a survey of builders on this topic, one of the challenges identifi ed is an industry-wide concern about the long-term moisture performance of energy-effi cient walls. This study takes a step toward addressing this concern through direct monitoring of themore » moisture performance of high-R walls in occupied homes in several climate zones. In addition, the robustness of the design and modeling tools for selecting high-R wall solutions is evaluated using the monitored data from the field. The information and knowledge gained through this research will provide an objective basis for decision-making so that builders can implement advanced designs with confidence.« less

Pine growth following chemical site prep and postplant herbaceous weed control compared to chemical site prep only

Treesearch

Dwight K. Lauer; Harold E. Quicke

2013-01-01

Three site prep vegetation control systems were compared on two Piedmont and two Upper Coastal Plain sites. Systems were (1) a one-time site prep application of Chopper® GEN2™ 2, (2) a one-time application of Chopper® GEN2™ tank mixed with sulfometuron, and (3) two applications consisting of site prep with Chopper® GEN2™ followed by herbaceous weed control with Arsenal...

High-performance computing — an overview

NASA Astrophysics Data System (ADS)

Marksteiner, Peter

1996-08-01

An overview of high-performance computing (HPC) is given. Different types of computer architectures used in HPC are discussed: vector supercomputers, high-performance RISC processors, various parallel computers like symmetric multiprocessors, workstation clusters, massively parallel processors. Software tools and programming techniques used in HPC are reviewed: vectorizing compilers, optimization and vector tuning, optimization for RISC processors; parallel programming techniques like shared-memory parallelism, message passing and data parallelism; and numerical libraries.

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…

High performance aluminum–cerium alloys for high-temperature applications

DOE PAGES

Sims, Zachary C.; Rios, Orlando R.; Weiss, David; ...

2017-08-01

Light-weight high-temperature alloys are important to the transportation industry where weight, cost, and operating temperature are major factors in the design of energy efficient vehicles. Aluminum alloys fill this gap economically but lack high-temperature mechanical performance. Alloying aluminum with cerium creates a highly castable alloy, compatible with traditional aluminum alloy additions, that exhibits dramatically improved high-temperature performance. These compositions display a room temperature ultimate tensile strength of 400 MPa and yield strength of 320 MPa, with 80% mechanical property retention at 240 °C. A mechanism is identified that addresses the mechanical property stability of the Al-alloys to at least 300more » °C and their microstructural stability to above 500 °C which may enable applications without the need for heat treatment. Lastly, neutron diffraction under load provides insight into the unusual mechanisms driving the mechanical strength.« less

High-Performance Computing User Facility | Computational Science | NREL

Science.gov Websites

User Facility High-Performance Computing User Facility The High-Performance Computing User Facility technologies. Photo of the Peregrine supercomputer The High Performance Computing (HPC) User Facility provides Gyrfalcon Mass Storage System. Access Our HPC User Facility Learn more about these systems and how to access

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.

LOCO with a Shipboard Lidar

DTIC Science & Technology

2008-01-01

components attached. The laser is located on the far left corner of the bench the pulse chopper assembly and beam expansion optics are at center. The IMU...access to the computer and receivers. Modifications were also made to lock the alignment of the beam through the chopper to increase the output...Receiver 2 CPU & Digitizer Laser Head Pulse Chopper 100 cm 56 cm GPS & INS Therm al M anagem ent 56 cm INS Laser PC & Digitize TE cooler Page 6 of

Promising high monetary rewards for future task performance increases intermediate task performance.

PubMed

Zedelius, Claire M; Veling, Harm; Bijleveld, Erik; Aarts, Henk

2012-01-01

In everyday life contexts and work settings, monetary rewards are often contingent on future performance. Based on research showing that the anticipation of rewards causes improved task performance through enhanced task preparation, the present study tested the hypothesis that the promise of monetary rewards for future performance would not only increase future performance, but also performance on an unrewarded intermediate task. Participants performed an auditory Simon task in which they responded to two consecutive tones. While participants could earn high vs. low monetary rewards for fast responses to every second tone, their responses to the first tone were not rewarded. Moreover, we compared performance under conditions in which reward information could prompt strategic performance adjustments (i.e., when reward information was presented for a relatively long duration) to conditions preventing strategic performance adjustments (i.e., when reward information was presented very briefly). Results showed that high (vs. low) rewards sped up both rewarded and intermediate, unrewarded responses, and the effect was independent of the duration of reward presentation. Moreover, long presentation led to a speed-accuracy trade-off for both rewarded and unrewarded tones, whereas short presentation sped up responses to rewarded and unrewarded tones without this trade-off. These results suggest that high rewards for future performance boost intermediate performance due to enhanced task preparation, and they do so regardless whether people respond to rewards in a strategic or non-strategic manner.

Promising High Monetary Rewards for Future Task Performance Increases Intermediate Task Performance

PubMed Central

Zedelius, Claire M.; Veling, Harm; Bijleveld, Erik; Aarts, Henk

2012-01-01

In everyday life contexts and work settings, monetary rewards are often contingent on future performance. Based on research showing that the anticipation of rewards causes improved task performance through enhanced task preparation, the present study tested the hypothesis that the promise of monetary rewards for future performance would not only increase future performance, but also performance on an unrewarded intermediate task. Participants performed an auditory Simon task in which they responded to two consecutive tones. While participants could earn high vs. low monetary rewards for fast responses to every second tone, their responses to the first tone were not rewarded. Moreover, we compared performance under conditions in which reward information could prompt strategic performance adjustments (i.e., when reward information was presented for a relatively long duration) to conditions preventing strategic performance adjustments (i.e., when reward information was presented very briefly). Results showed that high (vs. low) rewards sped up both rewarded and intermediate, unrewarded responses, and the effect was independent of the duration of reward presentation. Moreover, long presentation led to a speed-accuracy trade-off for both rewarded and unrewarded tones, whereas short presentation sped up responses to rewarded and unrewarded tones without this trade-off. These results suggest that high rewards for future performance boost intermediate performance due to enhanced task preparation, and they do so regardless whether people respond to rewards in a strategic or non-strategic manner. PMID:22905145

Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

PubMed

Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

2017-09-01

A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Critical Factors Explaining the Leadership Performance of High-Performing Principals

ERIC Educational Resources Information Center

Hutton, Disraeli M.

2018-01-01

The study explored critical factors that explain leadership performance of high-performing principals and examined the relationship between these factors based on the ratings of school constituents in the public school system. The principal component analysis with the use of Varimax Rotation revealed that four components explain 51.1% of the…

High-performance liquid chromatography of oligoguanylates at high pH

NASA Technical Reports Server (NTRS)

Stribling, R.; Deamer, D. (Principal Investigator)

1991-01-01

Because of the stable self-structures formed by oligomers of guanosine, standard high-performance liquid chromatography techniques for oligonucleotide fractionation are not applicable. Previously, oligoguanylate separations have been carried out at pH 12 using RPC-5 as the packing material. While RPC-5 provides excellent separations, there are several limitations, including the lack of a commercially available source. This report describes a new anion-exchange high-performance liquid chromatography method using HEMA-IEC BIO Q, which successfully separates different forms of the guanosine monomer as well as longer oligoguanylates. The reproducibility and stability at high pH suggests a versatile role for this material.

Spectral line discriminator for passive detection of fluorescence

NASA Technical Reports Server (NTRS)

Kebabian, Paul L. (Inventor)

1996-01-01

A method and apparatus for detecting fluorescence from sunlit plants is based on spectral line discrimination using the A-band and B-band absorption of atmospheric oxygen. Light from a plant including scattered sunlight and the fluorescence from chlorophyll is passed through a chopper into a cell containing low-pressure, high-purity oxygen. A-band or B-band wavelengths present in the light are absorbed by the oxygen in the cell. When the chopper is closed, the absorbed light is remitted as fluorescence into a detector. The intensity of the fluorescence from the oxygen is proportional to the intensity of fluorescence from the plant.

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.

High Efficiency, High Performance Clothes Dryer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peter Pescatore; Phil Carbone

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 bothmore » 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

High Performance Pulse Tube Cryocoolers

NASA Astrophysics Data System (ADS)

Olson, J. R.; Roth, E.; Champagne, P.; Evtimov, B.; Nast, T. C.

2008-03-01

Lockheed Martin's Advanced Technology Center has been developing pulse tube cryocoolers for more than ten years. Recent innovations include successful testing of four-stage coldheads, no-load temperature below 4 K, and the recent development of a high-efficiency compressor. This paper discusses the predicted performance of single and multiple stage pulse tube coldheads driven by our new 6 kg "M5Midi" compressor, which is capable of 90% efficiency with 200 W input power, and a maximum input power of 1000 W. This compressor retains the simplicity of earlier LM-ATC compressors: it has a moving magnet and an external electrical coil, minimizing organics in the working gas and requiring no electrical penetrations through the pressure wall. Motor losses were minimized during design, resulting in a simple, easily-manufactured compressor with state-of-the-art motor efficiency. The predicted cryocooler performance is presented as simple formulae, allowing an engineer to include the impact of a highly-optimized cryocooler into a full system analysis. Performance is given as a function of the heat rejection temperature and the cold tip temperatures and cooling loads.

High performance HRM: NHS employee perspectives.

PubMed

Hyde, Paula; Sparrow, Paul; Boaden, Ruth; Harris, Claire

2013-01-01

The purpose of this paper is to examine National Health Service (NHS) employee perspectives of how high performance human resource (HR) practices contribute to their performance. The paper draws on an extensive qualitative study of the NHS. A novel two-part method was used; the first part used focus group data from managers to identify high-performance HR practices specific to the NHS. Employees then conducted a card-sort exercise where they were asked how or whether the practices related to each other and how each practice affected their work. In total, 11 high performance HR practices relevant to the NHS were identified. Also identified were four reactions to a range of HR practices, which the authors developed into a typology according to anticipated beneficiaries (personal gain, organisation gain, both gain and no-one gains). Employees were able to form their own patterns (mental models) of performance contribution for a range of HR practices (60 interviewees produced 91 groupings). These groupings indicated three bundles particular to the NHS (professional development, employee contribution and NHS deal). These mental models indicate employee perceptions about how health services are organised and delivered in the NHS and illustrate the extant mental models of health care workers. As health services are rearranged and financial pressures begin to bite, these mental models will affect employee reactions to changes both positively and negatively. The novel method allows for identification of mental models that explain how NHS workers understand service delivery. It also delineates the complex and varied relationships between HR practices and individual performance.

High skin temperature and hypohydration impair aerobic performance.

PubMed

Sawka, Michael N; Cheuvront, Samuel N; Kenefick, Robert W

2012-03-01

This paper reviews the roles of hot skin (>35°C) and body water deficits (>2% body mass; hypohydration) in impairing submaximal aerobic performance. Hot skin is associated with high skin blood flow requirements and hypohydration is associated with reduced cardiac filling, both of which act to reduce aerobic reserve. In euhydrated subjects, hot skin alone (with a modest core temperature elevation) impairs submaximal aerobic performance. Conversely, aerobic performance is sustained with core temperatures >40°C if skin temperatures are cool-warm when euhydrated. No study has demonstrated that high core temperature (∼40°C) alone, without coexisting hot skin, will impair aerobic performance. In hypohydrated subjects, aerobic performance begins to be impaired when skin temperatures exceed 27°C, and even warmer skin exacerbates the aerobic performance impairment (-1.5% for each 1°C skin temperature). We conclude that hot skin (high skin blood flow requirements from narrow skin temperature to core temperature gradients), not high core temperature, is the 'primary' factor impairing aerobic exercise performance when euhydrated and that hypohydration exacerbates this effect.

DistributedFBA.jl: High-level, high-performance flux balance analysis in Julia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heirendt, Laurent; Thiele, Ines; Fleming, Ronan M. T.

Flux balance analysis and its variants are widely used methods for predicting steady-state reaction rates in biochemical reaction networks. The exploration of high dimensional networks with such methods is currently hampered by software performance limitations. DistributedFBA.jl is a high-level, high-performance, open-source implementation of flux balance analysis in Julia. It is tailored to solve multiple flux balance analyses on a subset or all the reactions of large and huge-scale networks, on any number of threads or nodes. DistributedFBA.jl is a high-level, high-performance, open-source implementation of flux balance analysis in Julia. It is tailored to solve multiple flux balance analyses on amore » subset or all the reactions of large and huge-scale networks, on any number of threads or nodes.« less

DistributedFBA.jl: High-level, high-performance flux balance analysis in Julia

DOE PAGES

Heirendt, Laurent; Thiele, Ines; Fleming, Ronan M. T.

2017-01-16

Flux balance analysis and its variants are widely used methods for predicting steady-state reaction rates in biochemical reaction networks. The exploration of high dimensional networks with such methods is currently hampered by software performance limitations. DistributedFBA.jl is a high-level, high-performance, open-source implementation of flux balance analysis in Julia. It is tailored to solve multiple flux balance analyses on a subset or all the reactions of large and huge-scale networks, on any number of threads or nodes. DistributedFBA.jl is a high-level, high-performance, open-source implementation of flux balance analysis in Julia. It is tailored to solve multiple flux balance analyses on amore » subset or all the reactions of large and huge-scale networks, on any number of threads or nodes.« less

High-performance analysis of filtered semantic graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buluc, Aydin; Fox, Armando; Gilbert, John R.

2012-01-01

High performance is a crucial consideration when executing a complex analytic query on a massive semantic graph. In a semantic graph, vertices and edges carry "attributes" of various types. Analytic queries on semantic graphs typically depend on the values of these attributes; thus, the computation must either view the graph through a filter that passes only those individual vertices and edges of interest, or else must first materialize a subgraph or subgraphs consisting of only the vertices and edges of interest. The filtered approach is superior due to its generality, ease of use, and memory efficiency, but may carry amore » performance cost. In the Knowledge Discovery Toolbox (KDT), a Python library for parallel graph computations, the user writes filters in a high-level language, but those filters result in relatively low performance due to the bottleneck of having to call into the Python interpreter for each edge. In this work, we use the Selective Embedded JIT Specialization (SEJITS) approach to automatically translate filters defined by programmers into a lower-level efficiency language, bypassing the upcall into Python. We evaluate our approach by comparing it with the high-performance C++ /MPI Combinatorial BLAS engine, and show that the productivity gained by using a high-level filtering language comes without sacrificing performance.« less

Rotordynamic Instability Problems in High-Performance Turbomachinery

NASA Technical Reports Server (NTRS)

1984-01-01

Rotordynamics and predictions on the stability of characteristics of high performance turbomachinery were discussed. Resolutions of problems on experimental validation of the forces that influence rotordynamics were emphasized. The programs to predict or measure forces and force coefficients in high-performance turbomachinery are illustrated. Data to design new machines with enhanced stability characteristics or upgrading existing machines are presented.

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.

Laser-Extinction and High-Resolution Atmospheric Transmission Measurements Conducted at White Sands Missile Range, New Mexico, March 1979.

DTIC Science & Technology

1980-11-19

used is first collimated by auxiliary optics to a diameter of approximately 18 mm. The beam is then focused via the off-axis parabolic mirror shown in...RECEIVER STATIONARY OF AISZERO ~ PAR ABOLA PATH OR PATH - CHOPPER I 90cm 120 cm COLLIMATOR / COLLECTOR XMTR DMOBILE RCvR CAIBAIO C0J POSITION - ETECTOR

Improved confinement in highly powered high performance scenarios on DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrie, Thomas W.; Osborne, Thomas; Fenstermacher, Max E.

DIII-D has recently demonstrated improved energy confinement by injecting neutral deuterium gas into high performance near-double null divertor (DND) plasmas during high power operation. Representative parameters for these plasmas are: q 95 = 6, P IN up to 15 MW, H 98 = 1.4–1.8, and β N = 2.5–4.0. The ion B xmore » $$\\triangledown$$B direction is away from the primary X-point. While plasma conditions at lower to moderate power input (e.g., 11 MW) are shown to be favorable to successful puff-and-pump radiating divertor applications, particularly when using argon seeds, plasma behavior at higher powers (e.g., ≥14 MW) may make successful puff-and-pump operation more problematic. In contrast to lower powered high performance plasmas, both $$\\tau$$ E and β N in the high power cases (≥14 MW) increased and ELM frequency decreased, as density was raised by deuterium gas injection. Improved performance in the higher power plasmas was tied to higher pedestal pressure, which according to peeling-ballooning mode stability analysis using the ELITE code could increase with density along the kink/peeling stability threshold, while the pedestal pressure gradient in the lower power discharges were limited by the ballooning threshold. This resulted in improved fueling efficiency and ≈10% higher $$\\tau$$ E and β N than is normally observed in comparable high performance plasmas on DIII-D. Applying the puff-and-pump radiating divertor approach at moderate versus high power input is shown to result in a much different evolution in core and pedestal plasma behavior. In conclusion, we find that injecting deuterium gas into these highly powered DND plasmas may open up a new avenue for achieving elevated plasma performance, including better fueling, but the resulting higher density may also complicate application of a radiating divertor approach to heat flux reduction in present-day tokamaks, if scenarios involving second-harmonic electron cyclotron heating are used.« less

Improved confinement in highly powered high performance scenarios on DIII-D

DOE PAGES

Petrie, Thomas W.; Osborne, Thomas; Fenstermacher, Max E.; ...

2017-06-09

DIII-D has recently demonstrated improved energy confinement by injecting neutral deuterium gas into high performance near-double null divertor (DND) plasmas during high power operation. Representative parameters for these plasmas are: q 95 = 6, P IN up to 15 MW, H 98 = 1.4–1.8, and β N = 2.5–4.0. The ion B xmore » $$\\triangledown$$B direction is away from the primary X-point. While plasma conditions at lower to moderate power input (e.g., 11 MW) are shown to be favorable to successful puff-and-pump radiating divertor applications, particularly when using argon seeds, plasma behavior at higher powers (e.g., ≥14 MW) may make successful puff-and-pump operation more problematic. In contrast to lower powered high performance plasmas, both $$\\tau$$ E and β N in the high power cases (≥14 MW) increased and ELM frequency decreased, as density was raised by deuterium gas injection. Improved performance in the higher power plasmas was tied to higher pedestal pressure, which according to peeling-ballooning mode stability analysis using the ELITE code could increase with density along the kink/peeling stability threshold, while the pedestal pressure gradient in the lower power discharges were limited by the ballooning threshold. This resulted in improved fueling efficiency and ≈10% higher $$\\tau$$ E and β N than is normally observed in comparable high performance plasmas on DIII-D. Applying the puff-and-pump radiating divertor approach at moderate versus high power input is shown to result in a much different evolution in core and pedestal plasma behavior. In conclusion, we find that injecting deuterium gas into these highly powered DND plasmas may open up a new avenue for achieving elevated plasma performance, including better fueling, but the resulting higher density may also complicate application of a radiating divertor approach to heat flux reduction in present-day tokamaks, if scenarios involving second-harmonic electron cyclotron heating are used.« less

High-Performance Bipropellant Engine

NASA Technical Reports Server (NTRS)

Biaglow, James A.; Schneider, Steven J.

1999-01-01

TRW, under contract to the NASA Lewis Research Center, has successfully completed over 10 000 sec of testing of a rhenium thrust chamber manufactured via a new-generation powder metallurgy. High performance was achieved for two different propellants, N2O4- N2H4 and N2O4 -MMH. TRW conducted 44 tests with N2O4-N2H4, accumulating 5230 sec of operating time with maximum burn times of 600 sec and a specific impulse Isp of 333 sec. Seventeen tests were conducted with N2O4-MMH for an additional 4789 sec and a maximum Isp of 324 sec, with a maximum firing duration of 700 sec. Together, the 61 tests totalled 10 019 sec of operating time, with the chamber remaining in excellent condition. Of these tests, 11 lasted 600 to 700 sec. The performance of radiation-cooled rocket engines is limited by their operating temperature. For the past two to three decades, the majority of radiation-cooled rockets were composed of a high-temperature niobium alloy (C103) with a disilicide oxide coating (R512) for oxidation resistance. The R512 coating practically limits the operating temperature to 1370 C. For the Earth-storable bipropellants commonly used in satellite and spacecraft propulsion systems, a significant amount of fuel film cooling is needed. The large film-cooling requirement extracts a large penalty in performance from incomplete mixing and combustion. A material system with a higher temperature capability has been matured to the point where engines are being readied for flight, particularly the 100-lb-thrust class engine. This system has powder rhenium (Re) as a substrate material with an iridium (Ir) oxidation-resistant coating. Again, the operating temperature is limited by the coating; however, Ir is capable of long-life operation at 2200 C. For Earth-storable bipropellants, this allows for the virtual elimination of fuel film cooling (some film cooling is used for thermal control of the head end). This has resulted in significant increases in specific impulse performance

High-Quality Carbohydrates and Physical Performance

PubMed Central

Kanter, Mitch

2018-01-01

While all experts agreed that protein needs for performance are likely greater than believed in past generations, particularly for strength training athletes, and that dietary fat could sustain an active person through lower-intensity training bouts, current research still points to carbohydrate as an indispensable energy source for high-intensity performance. PMID:29449746

Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

NASA Astrophysics Data System (ADS)

Ersez, Tunay; Esposto, Fernando; Souza, Nicolas R. de

2017-09-01

The shielding for the neutron high-resolution backscattering spectrometer (EMU) located at the OPAL reactor (ANSTO) was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

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.

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.

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.

High Performance Work System, HRD Climate and Organisational Performance: An Empirical Study

ERIC Educational Resources Information Center

Muduli, Ashutosh

2015-01-01

Purpose: This paper aims to study the relationship between high-performance work system (HPWS) and organizational performance and to examine the role of human resource development (HRD) Climate in mediating the relationship between HPWS and the organizational performance in the context of the power sector of India. Design/methodology/approach: The…

Approaches to High-Performance Preparative Chromatography of Proteins

NASA Astrophysics Data System (ADS)

Sun, Yan; Liu, Fu-Feng; Shi, Qing-Hong

Preparative liquid chromatography is widely used for the purification of chemical and biological substances. Different from high-performance liquid chromatography for the analysis of many different components at minimized sample loading, high-performance preparative chromatography is of much larger scale and should be of high resolution and high capacity at high operation speed and low to moderate pressure drop. There are various approaches to this end. For biochemical engineers, the traditional way is to model and optimize a purification process to make it exert its maximum capability. For high-performance separations, however, we need to improve chromatographic technology itself. We herein discuss four approaches in this review, mainly based on the recent studies in our group. The first is the development of high-performance matrices, because packing material is the central component of chromatography. Progress in the fabrication of superporous materials in both beaded and monolithic forms are reviewed. The second topic is the discovery and design of affinity ligands for proteins. In most chromatographic methods, proteins are separated based on their interactions with the ligands attached to the surface of porous media. A target-specific ligand can offer selective purification of desired proteins. Third, electrochromatography is discussed. An electric field applied to a chromatographic column can induce additional separation mechanisms besides chromatography, and result in electrokinetic transport of protein molecules and/or the fluid inside pores, thus leading to high-performance separations. Finally, expanded-bed adsorption is described for process integration to reduce separation steps and process time.

Noise of High-Performance Aircraft at Afterburner

DTIC Science & Technology

2015-03-30

Quarterly progress report 3. DATES COVERED (From - To) 12-15-2014 to 04-03-2015 4. TITLE AND SUBTITLE Noise of High-Performance Aircraft at Afterburner ...generation of a high- performance aircraft operating at afterburner condition. The new noise components are indirect combustion noise produced by the...spectrum is reported 15. SUBJECT TERMS Jet noise at afterburner 16. SECURITY CLASSIFICATION OF: a. REPORT u b. ABSTRACT u c. THIS PAGE u 17

3D printed high performance strain sensors for high temperature applications

NASA Astrophysics Data System (ADS)

Rahman, Md Taibur; Moser, Russell; Zbib, Hussein M.; Ramana, C. V.; Panat, Rahul

2018-01-01

Realization of high temperature physical measurement sensors, which are needed in many of the current and emerging technologies, is challenging due to the degradation of their electrical stability by drift currents, material oxidation, thermal strain, and creep. In this paper, for the first time, we demonstrate that 3D printed sensors show a metamaterial-like behavior, resulting in superior performance such as high sensitivity, low thermal strain, and enhanced thermal stability. The sensors were fabricated using silver (Ag) nanoparticles (NPs), using an advanced Aerosol Jet based additive printing method followed by thermal sintering. The sensors were tested under cyclic strain up to a temperature of 500 °C and showed a gauge factor of 3.15 ± 0.086, which is about 57% higher than that of those available commercially. The sensor thermal strain was also an order of magnitude lower than that of commercial gages for operation up to a temperature of 500 °C. An analytical model was developed to account for the enhanced performance of such printed sensors based on enhanced lateral contraction of the NP films due to the porosity, a behavior akin to cellular metamaterials. The results demonstrate the potential of 3D printing technology as a pathway to realize highly stable and high-performance sensors for high temperature applications.

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.

Type-II Superlattice for High Performance LWIR Detectors

DTIC Science & Technology

2008-05-15

Superlattice for High Performance LWIR Detectors 5. FUNDING NUMBERS F49620-03-1-0436 6. AUTHOR(S) M. Razeghi 7. PERFORMING ORGANIZATION NAME(S...298 (Rcv.2-89) Prescribed by ANSI Std. 239-18 298-102 Final Technical Report Type-II Superlattice for High Performance LWIR Detectors Contract No...Short-period InAs/GaSb type-II superlattices for mid- infrared detectors . Physica E: Low- dimensional Systems and Nanostructures, 2006.

High-Performance Java Codes for Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Riley, Christopher; Chatterjee, Siddhartha; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2001-01-01

The computational science community is reluctant to write large-scale computationally -intensive applications in Java due to concerns over Java's poor performance, despite the claimed software engineering advantages of its object-oriented features. Naive Java implementations of numerical algorithms can perform poorly compared to corresponding Fortran or C implementations. To achieve high performance, Java applications must be designed with good performance as a primary goal. This paper presents the object-oriented design and implementation of two real-world applications from the field of Computational Fluid Dynamics (CFD): a finite-volume fluid flow solver (LAURA, from NASA Langley Research Center), and an unstructured mesh adaptation algorithm (2D_TAG, from NASA Ames Research Center). This work builds on our previous experience with the design of high-performance numerical libraries in Java. We examine the performance of the applications using the currently available Java infrastructure and show that the Java version of the flow solver LAURA performs almost within a factor of 2 of the original procedural version. Our Java version of the mesh adaptation algorithm 2D_TAG performs within a factor of 1.5 of its original procedural version on certain platforms. Our results demonstrate that object-oriented software design principles are not necessarily inimical to high performance.

High Skin Temperature and Hypohydration Impair Aerobic Performance

DTIC Science & Technology

2012-01-01

hypohydration) in impairing submaximal aerobic performance. Hot skin is associated with high skin blood flow requirements and hypohydration is...the aerobic performance impairment (-1.5% for each l°C skin temperature). We conclude that hot skin ( high skin blood flow requirements from narrow...associated with high skin blood flow requirements and hypohydration is associated with reduced cardiac filling, both of which act to reduce aerobic

High Performance Parallel Computational Nanotechnology

NASA Technical Reports Server (NTRS)

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

1995-01-01

At a recent press conference, NASA Administrator Dan Goldin encouraged NASA Ames Research Center to take a lead role in promoting research and development of advanced, high-performance computer technology, including nanotechnology. Manufacturers of leading-edge microprocessors currently perform large-scale simulations in the design and verification of semiconductor devices and microprocessors. Recently, the need for this intensive simulation and modeling analysis has greatly increased, due in part to the ever-increasing complexity of these devices, as well as the lessons of experiences such as the Pentium fiasco. Simulation, modeling, testing, and validation will be even more important for designing molecular computers because of the complex specification of millions of atoms, thousands of assembly steps, as well as the simulation and modeling needed to ensure reliable, robust and efficient fabrication of the molecular devices. The software for this capacity does not exist today, but it can be extrapolated from the software currently used in molecular modeling for other applications: semi-empirical methods, ab initio methods, self-consistent field methods, Hartree-Fock methods, molecular mechanics; and simulation methods for diamondoid structures. In as much as it seems clear that the application of such methods in nanotechnology will require powerful, highly powerful systems, this talk will discuss techniques and issues for performing these types of computations on parallel systems. We will describe system design issues (memory, I/O, mass storage, operating system requirements, special user interface issues, interconnects, bandwidths, and programming languages) involved in parallel methods for scalable classical, semiclassical, quantum, molecular mechanics, and continuum models; molecular nanotechnology computer-aided designs (NanoCAD) techniques; visualization using virtual reality techniques of structural models and assembly sequences; software required to

Optical interconnection networks for high-performance computing systems

NASA Astrophysics Data System (ADS)

Biberman, Aleksandr; Bergman, Keren

2012-04-01

Enabled by silicon photonic technology, optical interconnection networks have the potential to be a key disruptive technology in computing and communication industries. The enduring pursuit of performance gains in computing, combined with stringent power constraints, has fostered the ever-growing computational parallelism associated with chip multiprocessors, memory systems, high-performance computing systems and data centers. Sustaining these parallelism growths introduces unique challenges for on- and off-chip communications, shifting the focus toward novel and fundamentally different communication approaches. Chip-scale photonic interconnection networks, enabled by high-performance silicon photonic devices, offer unprecedented bandwidth scalability with reduced power consumption. We demonstrate that the silicon photonic platforms have already produced all the high-performance photonic devices required to realize these types of networks. Through extensive empirical characterization in much of our work, we demonstrate such feasibility of waveguides, modulators, switches and photodetectors. We also demonstrate systems that simultaneously combine many functionalities to achieve more complex building blocks. We propose novel silicon photonic devices, subsystems, network topologies and architectures to enable unprecedented performance of these photonic interconnection networks. Furthermore, the advantages of photonic interconnection networks extend far beyond the chip, offering advanced communication environments for memory systems, high-performance computing systems, and data centers.

High-performance, stretchable, wire-shaped supercapacitors.

PubMed

Chen, Tao; Hao, Rui; Peng, Huisheng; Dai, Liming

2015-01-07

A general approach toward extremely stretchable and highly conductive electrodes was developed. The method involves wrapping a continuous carbon nanotube (CNT) thin film around pre-stretched elastic wires, from which high-performance, stretchable wire-shaped supercapacitors were fabricated. The supercapacitors were made by twisting two such CNT-wrapped elastic wires, pre-coated with poly(vinyl alcohol)/H3PO4 hydrogel, as the electrolyte and separator. The resultant wire-shaped supercapacitors exhibited an extremely high elasticity of up to 350% strain with a high device capacitance up to 30.7 F g(-1), which is two times that of the state-of-the-art stretchable supercapacitor under only 100% strain. The wire-shaped structure facilitated the integration of multiple supercapacitors into a single wire device to meet specific energy and power needs for various potential applications. These supercapacitors can be repeatedly stretched from 0 to 200% strain for hundreds of cycles with no change in performance, thus outperforming all the reported state-of-the-art stretchable electronics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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

The High-Speed Research Program sponsored the NASA High-Speed Research Program Aerodynamic Performance 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 areas of: Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization) and High-Lift. 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 scientist and engineers working HSCT aerodynamics. The HSR AP 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 within the airframe element of the HSR Program. This Volume 2/Part 1 publication presents the High-Lift Configuration Development session.

Archaeological Investigations at Site 45-DO-273, Chief Joseph Dam Project, Washington.

DTIC Science & Technology

1984-01-01

CHOPPERS . .. ........................... 60 DRILLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 GRAVERS...6 Plate 3-1. Shaft abrader, hammerstones, netslnker, and chopper . . . . 50 Plate 3-2. Blfaces and scrapers .. .. .. .... ... .... . ... 58 Plate 3...sites as low as possible. * . The Project’s Investigations are documented In four report series. Reports describing archaeological reconnaissance and

High performance, high bandgap, lattice-mismatched, GaInP solar cells

DOEpatents

Wanlass, Mark W; Carapella, Jeffrey J; Steiner, Myles A

2016-11-01

High performance, high bandgap, lattice-mismatched, photovoltaic cells (10), both transparent and non-transparent to sub-bandgap light, are provided as devices for use alone or in combination with other cells in split spectrum apparatus or other applications.

High performance, high bandgap, lattice-mismatched, GaInP solar cells

DOEpatents

Wanlass, Mark W.; Carapella, Jeffrey J.; Steiner, Myles A.

2014-07-08

High performance, high bandgap, lattice-mismatched, photovoltaic cells (10), both transparent and non-transparent to sub-bandgap light, are provided as devices for use alone or in combination with other cells in split spectrum apparatus or other applications.

Nonacademic Effects of Homework in Privileged, High-Performing High Schools

ERIC Educational Resources Information Center

Galloway, Mollie; Conner, Jerusha; Pope, Denise

2013-01-01

This study used survey data to examine relations among homework, student well-being, and behavioral engagement in a sample of 4,317 students from 10 high-performing high schools in upper middle class communities. Results indicated that students in these schools average more than 3 hr of homework per night. Students who did more hours of homework…

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.

Quantum Accelerators for High-performance Computing Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Humble, Travis S.; Britt, Keith A.; Mohiyaddin, Fahd A.

We define some of the programming and system-level challenges facing the application of quantum processing to high-performance computing. Alongside barriers to physical integration, prominent differences in the execution of quantum and conventional programs challenges the intersection of these computational models. Following a brief overview of the state of the art, we discuss recent advances in programming and execution models for hybrid quantum-classical computing. We discuss a novel quantum-accelerator framework that uses specialized kernels to offload select workloads while integrating with existing computing infrastructure. We elaborate on the role of the host operating system to manage these unique accelerator resources, themore » prospects for deploying quantum modules, and the requirements placed on the language hierarchy connecting these different system components. We draw on recent advances in the modeling and simulation of quantum computing systems with the development of architectures for hybrid high-performance computing systems and the realization of software stacks for controlling quantum devices. Finally, we present simulation results that describe the expected system-level behavior of high-performance computing systems composed from compute nodes with quantum processing units. We describe performance for these hybrid systems in terms of time-to-solution, accuracy, and energy consumption, and we use simple application examples to estimate the performance advantage of quantum acceleration.« less

Performance model-directed data sieving for high-performance I/O

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yong; Lu, Yin; Amritkar, Prathamesh

2014-09-10

Many scientific computing applications and engineering simulations exhibit noncontiguous I/O access patterns. Data sieving is an important technique to improve the performance of noncontiguous I/O accesses by combining small and noncontiguous requests into a large and contiguous request. It has been proven effective even though more data are potentially accessed than demanded. In this study, we propose a new data sieving approach namely performance model-directed data sieving, or PMD data sieving in short. It improves the existing data sieving approach from two aspects: (1) dynamically determines when it is beneficial to perform data sieving; and (2) dynamically determines how tomore » perform data sieving if beneficial. It improves the performance of the existing data sieving approach considerably and reduces the memory consumption as verified by both theoretical analysis and experimental results. Given the importance of supporting noncontiguous accesses effectively and reducing the memory pressure in a large-scale system, the proposed PMD data sieving approach in this research holds a great promise and will have an impact on high-performance I/O systems.« less

Silicon photonics for high-performance interconnection networks

NASA Astrophysics Data System (ADS)

Biberman, Aleksandr

2011-12-01

We assert in the course of this work that silicon photonics has the potential to be a key disruptive technology in computing and communication industries. The enduring pursuit of performance gains in computing, combined with stringent power constraints, has fostered the ever-growing computational parallelism associated with chip multiprocessors, memory systems, high-performance computing systems, and data centers. Sustaining these parallelism growths introduces unique challenges for on- and off-chip communications, shifting the focus toward novel and fundamentally different communication approaches. This work showcases that chip-scale photonic interconnection networks, enabled by high-performance silicon photonic devices, enable unprecedented bandwidth scalability with reduced power consumption. We demonstrate that the silicon photonic platforms have already produced all the high-performance photonic devices required to realize these types of networks. Through extensive empirical characterization in much of this work, we demonstrate such feasibility of waveguides, modulators, switches, and photodetectors. We also demonstrate systems that simultaneously combine many functionalities to achieve more complex building blocks. Furthermore, we leverage the unique properties of available silicon photonic materials to create novel silicon photonic devices, subsystems, network topologies, and architectures to enable unprecedented performance of these photonic interconnection networks and computing systems. We show that the advantages of photonic interconnection networks extend far beyond the chip, offering advanced communication environments for memory systems, high-performance computing systems, and data centers. Furthermore, we explore the immense potential of all-optical functionalities implemented using parametric processing in the silicon platform, demonstrating unique methods that have the ability to revolutionize computation and communication. Silicon photonics

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.

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. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Personality Types of Illinois Elementary Principals in High-Poverty, High-Performing Schools

ERIC Educational Resources Information Center

Hollowell, Daniel R.

2016-01-01

The socio-economic achievement gap is prevalent in schools across the country. There are many high-poverty, high-performing schools that have been successful in closing this achievement gap. This study investigated 30 Illinois elementary school principals from high-poverty, high-achieving schools. Principals were given the Myers-Briggs Type…

Ultra-compact high-performance MCT MWIR engine

NASA Astrophysics Data System (ADS)

Lutz, H.; Breiter, R.; Eich, D.; Figgemeier, H.; Oelmaier, R.; Rutzinger, S.; Schenk, H.; Wendler, J.

2017-02-01

Size, weight and power (SWaP) reduction is highly desired by applications such as sights for the dismounted soldier or small gimbals for UAVs. But why have high performance and small size of IR systems inevitably exclude each other? Namely, recent development progress in the fields of miniature cryocoolers, short dewars and high operating temperature (HOT) FPAs combined with pitch size reduction opens the door for very compact MWIR-modules while keeping high electro-optical performance. Now, AIM has realized first prototypes of an ultra-compact high-performance MWIR engine in a total volume of only 18cl (60mm length x 60mm height x 50mm width). Impressive SWaP characteristics are completed by a total weight below 400g and a power consumption < 4W in basic imaging mode. The engine consists of a XGA-format (1024x768) MCT detector array with 10μm pitch and a low power consuming ROIC. It is cooled down to a typical operating temperature of 160K by the miniature linear cryocooler SX020. The dewar uses a short coldfinger and is designed to reduce the heat load as much as possible. The cooler drive electronics is implemented in the CCE layout in order to reduce the required space of the printed boards and to save power. Uncorrected 14bit video data is provided via Camera Link. Optionally, a small image processing board can be stacked on top of the CCE to gain access to basic functions such as BPR, 2- point NUC and dynamic reduction. This paper will present the design, functionalities and performance data of the ultra-compact MCT MWIR engine operated at HOT.

High performance bonded neo magnets using high density compaction

NASA Astrophysics Data System (ADS)

Herchenroeder, J.; Miller, D.; Sheth, N. K.; Foo, M. C.; Nagarathnam, K.

2011-04-01

This paper presents a manufacturing method called Combustion Driven Compaction (CDC) for the manufacture of isotropic bonded NdFeB magnets (bonded Neo). Magnets produced by the CDC method have density up to 6.5 g/cm3 which is 7-10% higher compared to commercially available bonded Neo magnets of the same shape. The performance of an actual seat motor with a representative CDC ring magnet is presented and compared with the seat motor performance with both commercial isotropic bonded Neo and anisotropic NdFeB rings of the same geometry. The comparisons are made at both room and elevated temperatures. The airgap flux for the magnet produced by the proposed method is 6% more compared to the commercial isotropic bonded Neo magnet. After exposure to high temperature due to the superior thermal aging stability of isotropic NdFeB powders the motor performance with this material is comparable to the motor performance with an anisotropic NdFeB magnet.

Training | High-Performance Computing | NREL

Science.gov Websites

Training Training Find training resources for using NREL's high-performance computing (HPC) systems as well as related online tutorials. Upcoming Training HPC User Workshop - June 12th We will be Conference, a group meets to discuss Best Practices in HPC Training. This group developed a list of resources

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.

Can Knowledge of the Characteristics of "High Performers" Be Generalised?

ERIC Educational Resources Information Center

McKenna, Stephen

2002-01-01

Two managers described as high performing constructed complexity maps of their organization/world. The maps suggested that high performance is socially constructed and negotiated in specific contexts and management competencies associated with it are context specific. Development of high performers thus requires personalized coaching more than…

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.

Oasis: A high-level/high-performance open source Navier-Stokes solver

NASA Astrophysics Data System (ADS)

Mortensen, Mikael; Valen-Sendstad, Kristian

2015-03-01

Oasis is a high-level/high-performance finite element Navier-Stokes solver written from scratch in Python using building blocks from the FEniCS project (fenicsproject.org). The solver is unstructured and targets large-scale applications in complex geometries on massively parallel clusters. Oasis utilizes MPI and interfaces, through FEniCS, to the linear algebra backend PETSc. Oasis advocates a high-level, programmable user interface through the creation of highly flexible Python modules for new problems. Through the high-level Python interface the user is placed in complete control of every aspect of the solver. A version of the solver, that is using piecewise linear elements for both velocity and pressure, is shown to reproduce very well the classical, spectral, turbulent channel simulations of Moser et al. (1999). The computational speed is strongly dominated by the iterative solvers provided by the linear algebra backend, which is arguably the best performance any similar implicit solver using PETSc may hope for. Higher order accuracy is also demonstrated and new solvers may be easily added within the same framework.

Scout: high-performance heterogeneous computing made simple

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jablin, James; Mc Cormick, Patrick; Herlihy, Maurice

2011-01-26

Researchers must often write their own simulation and analysis software. During this process they simultaneously confront both computational and scientific problems. Current strategies for aiding the generation of performance-oriented programs do not abstract the software development from the science. Furthermore, the problem is becoming increasingly complex and pressing with the continued development of many-core and heterogeneous (CPU-GPU) architectures. To acbieve high performance, scientists must expertly navigate both software and hardware. Co-design between computer scientists and research scientists can alleviate but not solve this problem. The science community requires better tools for developing, optimizing, and future-proofing codes, allowing scientists to focusmore » on their research while still achieving high computational performance. Scout is a parallel programming language and extensible compiler framework targeting heterogeneous architectures. It provides the abstraction required to buffer scientists from the constantly-shifting details of hardware while still realizing higb-performance by encapsulating software and hardware optimization within a compiler framework.« less

Strategies to achieve long-term benefits from multiple operational herbicide applications in lower coastal plain pine stands

Treesearch

Harold E. Quicke; Dwight K. Lauer

2010-01-01

Studies were installed on a range of soils to examine different post-plant herbaceous weed control timings following different site preparation timings with Chopper® herbicide. Chopper site preparation treatments were applied after bedding and included two application dates (August versus November). Pines were planted in winter following site preparation. Site...

Straight and chopped dc performance data for a Prestolite MTC-4001 motor and a general electric EV-1 controller

NASA Technical Reports Server (NTRS)

Edie, P. C.

1981-01-01

Performance data on the Prestolite MTC-4001 series wound dc motor and General Electric EV-1 Chopper Controller is supplied for the electric vehicle manufacturer. Data are provided for both straight and chopped dc input to the motor, at 2 motor temperature levels. Testing was done at 6 voltage increments to the motor, and 2 voltage increments to the controller. Data results are presented in both tabular and graphical forms. Tabular information includes motor voltage and current input data, motor speed and torque output data, power data and temperature data. Graphical information includes torque-speed, motor power output-speed, torque-current, and efficiency-speed plots under the various operating conditions. The data resulting from this testing show the speed-torque plots to have the most variance with operating temperature. The maximum motor efficiency is between 76% and 82%, regardless of temperature or mode of operation.

Micromagnetics on high-performance workstation and mobile computational platforms

NASA Astrophysics Data System (ADS)

Fu, S.; Chang, R.; Couture, S.; Menarini, M.; Escobar, M. A.; Kuteifan, M.; Lubarda, M.; Gabay, D.; Lomakin, V.

2015-05-01

The feasibility of using high-performance desktop and embedded mobile computational platforms is presented, including multi-core Intel central processing unit, Nvidia desktop graphics processing units, and Nvidia Jetson TK1 Platform. FastMag finite element method-based micromagnetic simulator is used as a testbed, showing high efficiency on all the platforms. Optimization aspects of improving the performance of the mobile systems are discussed. The high performance, low cost, low power consumption, and rapid performance increase of the embedded mobile systems make them a promising candidate for micromagnetic simulations. Such architectures can be used as standalone systems or can be built as low-power computing clusters.

High-Performance, Semi-Interpenetrating Polymer Network

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Lowther, Sharon E.; Smith, Janice Y.; Cannon, Michelle S.; Whitehead, Fred M.; Ely, Robert M.

1992-01-01

High-performance polymer made by new synthesis in which one or more easy-to-process, but brittle, thermosetting polyimides combined with one or more tough, but difficult-to-process, linear thermoplastics to yield semi-interpenetrating polymer network (semi-IPN) having combination of easy processability and high tolerance to damage. Two commercially available resins combined to form tough, semi-IPN called "LaRC-RP49." Displays improvements in toughness and resistance to microcracking. LaRC-RP49 has potential as high-temperature matrix resin, adhesive, and molding resin. Useful in aerospace, automotive, and electronic industries.

Advances in Experiment Design for High Performance Aircraft

NASA Technical Reports Server (NTRS)

Morelli, Engene A.

1998-01-01

A general overview and summary of recent advances in experiment design for high performance aircraft is presented, along with results from flight tests. General theoretical background is included, with some discussion of various approaches to maneuver design. Flight test examples from the F-18 High Alpha Research Vehicle (HARV) are used to illustrate applications of the theory. Input forms are compared using Cramer-Rao bounds for the standard errors of estimated model parameters. Directions for future research in experiment design for high performance aircraft are identified.

Improving UV Resistance of High Performance Fibers

NASA Astrophysics Data System (ADS)

Hassanin, Ahmed

High performance fibers are characterized by their superior properties compared to the traditional textile fibers. High strength fibers have high modules, high strength to weight ratio, high chemical resistance, and usually high temperature resistance. It is used in application where superior properties are needed such as bulletproof vests, ropes and cables, cut resistant products, load tendons for giant scientific balloons, fishing rods, tennis racket strings, parachute cords, adhesives and sealants, protective apparel and tire cords. Unfortunately, Ultraviolet (UV) radiation causes serious degradation to the most of high performance fibers. UV lights, either natural or artificial, cause organic compounds to decompose and degrade, because the energy of the photons of UV light is high enough to break chemical bonds causing chain scission. This work is aiming at achieving maximum protection of high performance fibers using sheathing approaches. The sheaths proposed are of lightweight to maintain the advantage of the high performance fiber that is the high strength to weight ratio. This study involves developing three different types of sheathing. The product of interest that need be protected from UV is braid from PBO. First approach is extruding a sheath from Low Density Polyethylene (LDPE) loaded with different rutile TiO2 % nanoparticles around the braid from the PBO. The results of this approach showed that LDPE sheath loaded with 10% TiO2 by weight achieved the highest protection compare to 0% and 5% TiO2. The protection here is judged by strength loss of PBO. This trend noticed in different weathering environments, where the sheathed samples were exposed to UV-VIS radiations in different weatheromter equipments as well as exposure to high altitude environment using NASA BRDL balloon. The second approach is focusing in developing a protective porous membrane from polyurethane loaded with rutile TiO2 nanoparticles. Membrane from polyurethane loaded with 4

Beating the Odds: High Performing, Small High-Schools in the Rural South

ERIC Educational Resources Information Center

Rural School and Community Trust, 2004

2004-01-01

The Southern Rural High School Study Initiative seeks to identify high performing rural high schools in the South, engage education leaders in the region in analyzing the challenges faced by these schools and consider the public policies that might serve to transfer the lessons and strategies used by these schools to other small rural high schools…

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.

High performance sapphire windows

NASA Astrophysics Data System (ADS)

Bates, Stephen C.; Liou, Larry

1993-02-01

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.

Stretchable and high-performance supercapacitors with crumpled graphene papers.

PubMed

Zang, Jianfeng; Cao, Changyong; Feng, Yaying; Liu, Jie; Zhao, Xuanhe

2014-10-01

Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g(-1)), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance.

Stretchable and High-Performance Supercapacitors with Crumpled Graphene Papers

NASA Astrophysics Data System (ADS)

Zang, Jianfeng; Cao, Changyong; Feng, Yaying; Liu, Jie; Zhao, Xuanhe

2014-10-01

Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g-1), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance.

Stretchable and High-Performance Supercapacitors with Crumpled Graphene Papers

PubMed Central

Zang, Jianfeng; Cao, Changyong; Feng, Yaying; Liu, Jie; Zhao, Xuanhe

2014-01-01

Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g−1), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance. PMID:25270673

A probability metric for identifying high-performing facilities: an application for pay-for-performance programs.

PubMed

Shwartz, Michael; Peköz, Erol A; Burgess, James F; Christiansen, Cindy L; Rosen, Amy K; Berlowitz, Dan

2014-12-01

Two approaches are commonly used for identifying high-performing facilities on a performance measure: one, that the facility is in a top quantile (eg, quintile or quartile); and two, that a confidence interval is below (or above) the average of the measure for all facilities. This type of yes/no designation often does not do well in distinguishing high-performing from average-performing facilities. To illustrate an alternative continuous-valued metric for profiling facilities--the probability a facility is in a top quantile--and show the implications of using this metric for profiling and pay-for-performance. We created a composite measure of quality from fiscal year 2007 data based on 28 quality indicators from 112 Veterans Health Administration nursing homes. A Bayesian hierarchical multivariate normal-binomial model was used to estimate shrunken rates of the 28 quality indicators, which were combined into a composite measure using opportunity-based weights. Rates were estimated using Markov Chain Monte Carlo methods as implemented in WinBUGS. The probability metric was calculated from the simulation replications. Our probability metric allowed better discrimination of high performers than the point or interval estimate of the composite score. In a pay-for-performance program, a smaller top quantile (eg, a quintile) resulted in more resources being allocated to the highest performers, whereas a larger top quantile (eg, being above the median) distinguished less among high performers and allocated more resources to average performers. The probability metric has potential but needs to be evaluated by stakeholders in different types of delivery systems.

Female Leadership at High-Poverty, High-Performing Schools: Four Case Studies

ERIC Educational Resources Information Center

Reynolds, Shirley Ann

2009-01-01

This mixed methods study examined the leadership abilities of four African American female principals in an urban setting. The purpose of the mixed methods study was to observe, describe and analyze how the principals have been effective leaders in their respective high-poverty, high-performing elementary schools (K-5). The qualitative methodology…

Engineering High-Energy Interfacial Structures for High-Performance Oxygen-Involving Electrocatalysis.

PubMed

Guo, Chunxian; Zheng, Yao; Ran, Jingrun; Xie, Fangxi; Jaroniec, Mietek; Qiao, Shi-Zhang

2017-07-10

Engineering high-energy interfacial structures for high-performance electrocatalysis is achieved by chemical coupling of active CoO nanoclusters and high-index facet Mn 3 O 4 nano-octahedrons (hi-Mn 3 O 4 ). A thorough characterization, including synchrotron-based near edge X-ray absorption fine structure, reveals that strong interactions between both components promote the formation of high-energy interfacial Mn-O-Co species and high oxidation state CoO, from which electrons are drawn by Mn III -O present in hi-Mn 3 O 4 . The CoO/hi-Mn 3 O 4 demonstrates an excellent catalytic performance over the conventional metal oxide-based electrocatalysts, which is reflected by 1.2 times higher oxygen evolution reaction (OER) activity than that of Ru/C and a comparable oxygen reduction reaction (ORR) activity to that of Pt/C as well as a better stability than that of Ru/C (95 % vs. 81 % retained OER activity) and Pt/C (92 % vs. 78 % retained ORR activity after 10 h running) in alkaline electrolyte. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cultural characteristics of "high" and "low" performing hospitals.

PubMed

Mannion, R; Davies, H T O; Marshall, M N

2005-01-01

To compare and contrast the cultural characteristics of "high" and "low" performing hospitals in the UK National Health Service (NHS). A multiple case study design incorporating a purposeful sample of "low" and "high" performing acute hospital Trusts, as assessed by the star performance rating system. These case studies suggest that "high" and "low" performing acute hospital organisations may be very different environments in which to work. Although each case possessed its own unique character, significant patternings were observed within cases grouped by performance to suggest considerable cultural divergence. The key points of divergence can be grouped under four main headings: leadership and management orientation; accountability and information systems; human resources policies; and relationships within the local health economy. As with any study, interpretation of findings should be tempered with a degree of caution because of methodological considerations. First, there are the limitations of case study which proceeds on the basis of theoretical rather than quantitative generalisation. Second, organisational culture was assessed by exploring the views of middle and senior managers. While one should in no way suggest that such an approach can capture all important cultural characteristics of organisations, it is believed that it may be at least partially justified, given the agenda-setting powers and influence of the senior management team. Finally "star" performance measures are far from a perfect measure of organisational performance. Despite such reservations, the findings indicate that organisational culture is associated in a variety of non-trivial ways with the measured performance of hospital organisations. Highlights considerable cultural divergence within UK NHS hospitals.

Teacher Accountability at High Performing Charter Schools

ERIC Educational Resources Information Center

Aguirre, Moises G.

2016-01-01

This study will examine the teacher accountability and evaluation policies and practices at three high performing charter schools located in San Diego County, California. Charter schools are exempted from many laws, rules, and regulations that apply to traditional school systems. By examining the teacher accountability systems at high performing…

Compensated infrared absorption sensor for carbon dioxide and other infrared absorbing gases

DOEpatents

Owen, Thomas E.

2005-11-29

A gas sensor, whose chamber uses filters and choppers in either a semicircular geometry or annular geometry, and incorporates separate infrared radiation filters and optical choppers. This configuration facilitates the use of a single infrared radiation source and a single detector for infrared measurements at two wavelengths, such that measurement errors may be compensated.

High-Performance, Space-Storable, Bi-Propellant Program Status

NASA Technical Reports Server (NTRS)

Schneider, Steven J.

2002-01-01

Bipropellant propulsion systems currently represent the largest bus subsystem for many missions. These missions range from low Earth orbit satellite to geosynchronous communications and planetary exploration. The payoff of high performance bipropellant systems is illustrated by the fact that Aerojet Redmond has qualified a commercial NTO/MMH engine based on the high Isp technology recently delivered by this program. They are now qualifying a NTO/hydrazine version of this engine. The advanced rhenium thrust chambers recently provided by this program have raised the performance of earth storable propellants from 315 sec to 328 sec of specific impulse. The recently introduced rhenium technology is the first new technology introduced to satellite propulsion in 30 years. Typically, the lead time required to develop and qualify new chemical thruster technology is not compatible with program development schedules. These technology development programs must be supported by a long term, Base R&T Program, if the technology s to be matured. This technology program then addresses the need for high performance, storable, on-board chemical propulsion for planetary rendezvous and descent/ascent. The primary NASA customer for this technology is Space Science, which identifies this need for such programs as Mars Surface Return, Titan Explorer, Neptune Orbiter, and Europa Lander. High performance (390 sec) chemical propulsion is estimated to add 105% payload to the Mars Sample Return mission or alternatively reduce the launch mass by 33%. In many cases, the use of existing (flight heritage) propellant technology is accommodated by reducing mission objectives and/or increasing enroute travel times sacrificing the science value per unit cost of the program. Therefore, a high performance storable thruster utilizing fluorinated oxidizers with hydrazine is being developed.

WOMBAT: A Scalable and High-performance Astrophysical Magnetohydrodynamics Code

NASA Astrophysics Data System (ADS)

Mendygral, P. J.; Radcliffe, N.; Kandalla, K.; Porter, D.; O'Neill, B. J.; Nolting, C.; Edmon, P.; Donnert, J. M. F.; Jones, T. W.

2017-02-01

We present a new code for astrophysical magnetohydrodynamics specifically designed and optimized for high performance and scaling on modern and future supercomputers. We describe a novel hybrid OpenMP/MPI programming model that emerged from a collaboration between Cray, Inc. and the University of Minnesota. This design utilizes MPI-RMA optimized for thread scaling, which allows the code to run extremely efficiently at very high thread counts ideal for the latest generation of multi-core and many-core architectures. Such performance characteristics are needed in the era of “exascale” computing. We describe and demonstrate our high-performance design in detail with the intent that it may be used as a model for other, future astrophysical codes intended for applications demanding exceptional performance.

Ultra-high performance concrete for Michigan bridges, material performance : phase I.

DOT National Transportation Integrated Search

2008-10-13

One of the latest advancements in concrete technology is Ultra-High Performance Concrete (UHPC). UHPC is : defined as concretes attaining compressive strengths exceeding 25 ksi (175 MPa). It is a fiber-reinforced, denselypacked : concrete material wh...

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.

Design and Implementation of High-Performance GIS Dynamic Objects Rendering Engine

NASA Astrophysics Data System (ADS)

Zhong, Y.; Wang, S.; Li, R.; Yun, W.; Song, G.

2017-12-01

Spatio-temporal dynamic visualization is more vivid than static visualization. It important to use dynamic visualization techniques to reveal the variation process and trend vividly and comprehensively for the geographical phenomenon. To deal with challenges caused by dynamic visualization of both 2D and 3D spatial dynamic targets, especially for different spatial data types require high-performance GIS dynamic objects rendering engine. The main approach for improving the rendering engine with vast dynamic targets relies on key technologies of high-performance GIS, including memory computing, parallel computing, GPU computing and high-performance algorisms. In this study, high-performance GIS dynamic objects rendering engine is designed and implemented for solving the problem based on hybrid accelerative techniques. The high-performance GIS rendering engine contains GPU computing, OpenGL technology, and high-performance algorism with the advantage of 64-bit memory computing. It processes 2D, 3D dynamic target data efficiently and runs smoothly with vast dynamic target data. The prototype system of high-performance GIS dynamic objects rendering engine is developed based SuperMap GIS iObjects. The experiments are designed for large-scale spatial data visualization, the results showed that the high-performance GIS dynamic objects rendering engine have the advantage of high performance. Rendering two-dimensional and three-dimensional dynamic objects achieve 20 times faster on GPU than on CPU.

High-Performance Liquid Chromatography-Mass Spectrometry.

ERIC Educational Resources Information Center

Vestal, Marvin L.

1984-01-01

Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

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.

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.

High-performance scientific computing in the cloud

NASA Astrophysics Data System (ADS)

Jorissen, Kevin; Vila, Fernando; Rehr, John

2011-03-01

Cloud computing has the potential to open up high-performance computational science to a much broader class of researchers, owing to its ability to provide on-demand, virtualized computational resources. However, before such approaches can become commonplace, user-friendly tools must be developed that hide the unfamiliar cloud environment and streamline the management of cloud resources for many scientific applications. We have recently shown that high-performance cloud computing is feasible for parallelized x-ray spectroscopy calculations. We now present benchmark results for a wider selection of scientific applications focusing on electronic structure and spectroscopic simulation software in condensed matter physics. These applications are driven by an improved portable interface that can manage virtual clusters and run various applications in the cloud. We also describe a next generation of cluster tools, aimed at improved performance and a more robust cluster deployment. Supported by NSF grant OCI-1048052.

Artificial Intelligence Tools for Scaling Up of High Shear Wet Granulation Process.

PubMed

Landin, Mariana

2017-01-01

The results presented in this article demonstrate the potential of artificial intelligence tools for predicting the endpoint of the granulation process in high-speed mixer granulators of different scales from 25L to 600L. The combination of neurofuzzy logic and gene expression programing technologies allowed the modeling of the impeller power as a function of operation conditions and wet granule properties, establishing the critical variables that affect the response and obtaining a unique experimental polynomial equation (transparent model) of high predictability (R 2 > 86.78%) for all size equipment. Gene expression programing allowed the modeling of the granulation process for granulators of similar and dissimilar geometries and can be improved by implementing additional characteristics of the process, as composition variables or operation parameters (e.g., batch size, chopper speed). The principles and the methodology proposed here can be applied to understand and control manufacturing process, using any other granulation equipment, including continuous granulation processes. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

High-performance noncontact thermal diode via asymmetric nanostructures

NASA Astrophysics Data System (ADS)

Shen, Jiadong; Liu, Xianglei; He, Huan; Wu, Weitao; Liu, Baoan

2018-05-01

Electric diodes, though laying the foundation of modern electronics and information processing industries, suffer from ineffectiveness and even failure at high temperatures. Thermal diodes are promising alternatives to relieve above limitations, but usually possess low rectification ratios, and how to obtain a high-performance thermal rectification effect is still an open question. This paper proposes an efficient contactless thermal diode based on the near-field thermal radiation of asymmetric doped silicon nanostructures. The rectification ratio computed via exact scattering theories is demonstrated to be as high as 10 at a nanoscale gap distance and period, outperforming the counterpart flat-plate diode by more than one order of magnitude. This extraordinary performance mainly lies in the higher forward and lower reverse radiative heat flux within the low frequency band compared with the counterpart flat-plate diode, which is caused by a lower loss and smaller cut-off wavevector of nanostructures for the forward and reversed scheme, respectively. This work opens new routes to realize high performance thermal diodes, and may have wide applications in efficient thermal computing, thermal information processing, and thermal management.

High performance pipelined multiplier with fast carry-save adder

NASA Technical Reports Server (NTRS)

Wu, Angus

1990-01-01

A high-performance pipelined multiplier is described. Its high performance results from the fast carry-save adder basic cell which has a simple structure and is suitable for the Gate Forest semi-custom environment. The carry-save adder computes the sum and carry within two gate delay. Results show that the proposed adder can operate at 200 MHz for a 2-micron CMOS process; better performance is expected in a Gate Forest realization.

High-Performance Computing Data Center Warm-Water Liquid Cooling |

Science.gov Websites

Computational Science | NREL Warm-Water Liquid Cooling High-Performance Computing Data Center Warm-Water Liquid Cooling NREL's High-Performance Computing Data Center (HPC Data Center) is liquid water Liquid cooling technologies offer a more energy-efficient solution that also allows for effective

Effective Science Instruction: Impact on High-Stakes Assessment Performance

ERIC Educational Resources Information Center

Johnson, Carla C.; Zhang, Danhui; Kahle, Jane Butler

2012-01-01

This longitudinal prospective cohort study was conducted to determine the impact of effective science instruction on performance on high-stakes high school graduation assessments in science. This study provides powerful findings to support authentic science teaching to enhance long-term retention of learning and performance on state-mandated…

WOMBAT: A Scalable and High-performance Astrophysical Magnetohydrodynamics Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendygral, P. J.; Radcliffe, N.; Kandalla, K.

2017-02-01

We present a new code for astrophysical magnetohydrodynamics specifically designed and optimized for high performance and scaling on modern and future supercomputers. We describe a novel hybrid OpenMP/MPI programming model that emerged from a collaboration between Cray, Inc. and the University of Minnesota. This design utilizes MPI-RMA optimized for thread scaling, which allows the code to run extremely efficiently at very high thread counts ideal for the latest generation of multi-core and many-core architectures. Such performance characteristics are needed in the era of “exascale” computing. We describe and demonstrate our high-performance design in detail with the intent that it maymore » be used as a model for other, future astrophysical codes intended for applications demanding exceptional performance.« less

Anthropometry as a predictor of high speed performance.

PubMed

Caruso, J F; Ramey, E; Hastings, L P; Monda, J K; Coday, M A; McLagan, J; Drummond, J

2009-07-01

To assess anthropometry as a predictor of high-speed performance, subjects performed four seated knee- and hip-extension workouts with their left leg on an inertial exercise trainer (Impulse Technologies, Newnan GA). Workouts, done exclusively in either the tonic or phasic contractile mode, entailed two one-minute sets separated by a 90-second rest period and yielded three performance variables: peak force, average force and work. Subjects provided the following anthropometric data: height, weight, body mass index, as well as total, upper and lower left leg lengths. Via multiple regression, anthropometry attempted to predict the variance per performance variable. Anthropometry explained a modest (R2=0.27-0.43) yet significant degree of variance from inertial exercise trainer workouts. Anthropometry was a better predictor of peak force variance from phasic workouts, while it accounted for a significant degree of average force and work variance solely from tonic workouts. Future research should identify variables that account for the unexplained variance from high-speed exercise performance.

Q-Switching in a Neodymium Laser

ERIC Educational Resources Information Center

Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

2012-01-01

We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

AMOR - the time-of-flight neutron reflectometer at SINQ/PSI

NASA Astrophysics Data System (ADS)

Gupta, Mukul; Gutberlet, T.; Stahn, J.; Keller, P.; Clemens, D.

2004-07-01

The apparatus for multioptional reflectometry (AMOR) at SINQ/PSI is a versatile reflectometer operational in the time-of-flight (TOF) mode (in a wavelength range of 0.15 nm <λ < 1.3 nm) as well as in the monochromatic (theta-2theta) mode with both polarized and unpolarized neutrons. AMOR is designed to perform reflectometry measurements in horizontal sample-plane geometry which allows studying both solid-liquid and liquid-liquid interfaces. A pulsed cold neutron beam from the end position of the neutron guide is produced by a dual-chopper system (side-by-side) having two windows at 180^{circ} and rotatable with a maximum frequency of 200 Hz. In the TOF mode, the chopper frequency, width of the gating window and the chopper-detector distance can be selected independently providing a wide range of q-resolution (Delta q/q=1-10&%slash;). Remanent FeCoV/Ti : N supermirrors are used as polarizer/analyzer with a polarization efficiency of sim97&%slash;. For the monochromatic wavelength mode, a Ni/Ti multilayer is used as a monochromator, giving sim50&%slash; reflectivity at a wavelength of 0.47 nm. In the present work, a detailed description of the instrument and setting-up of the polarization option is described. Results from some of the recent studies with polarized neutrons and measurements on liquid surfaces are presented.

Proven high-performance display solution

NASA Astrophysics Data System (ADS)

Johnson, Rick J.; Shaw, James E.; Mosier, Don; Liss, Raymond L.; Prouty, Todd D.; Davis, Josh; Marzen, Vincent P.; Deloy, Christian T.

2002-08-01

Rockwell Collins serves both the military and the commercial segments by exploiting the common elements of these applications. Rockwell Collins has created a liquid crystal display family capable of 100:1 contrast ratio, 40:1 high ambient contrast, 0.25% specular reflectance, 0.1% diffuse reflectance, enhanced color stability over +/- 55H, 0-30V field of view, 300 fL with 10K:1 dimming range, color NVIS B compliance while exceeding environmental performance requirements though ruggedization. In order to meet the full range of display requirements at a system level, all the components must be understood and managed to meet the end solution of the final system. This paper details Rockwell Collins' optical performance using an avionics grade panel, third generation custom compensation, and solid state backlight.

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…

An Analysis of a High Performing School District's Culture

ERIC Educational Resources Information Center

Corum, Kenneth D.; Schuetz, Todd B.

2012-01-01

This report describes a problem based learning project focusing on the cultural elements of a high performing school district. Current literature on school district culture provides numerous cultural elements that are present in high performing school districts. With the current climate in education placing pressure on school districts to perform…

A Theoretical Structure of High School Concert Band Performance

ERIC Educational Resources Information Center

Bergee, Martin J.

2015-01-01

This study used exploratory (EFA) and confirmatory factor analysis (CFA) to verify a theoretical structure for high school concert band performance and to test that structure for viability, generality, and invariance. A total of 101 university students enrolled in two different bands rated two high school band performances (a "first"…

High-performance reactionless scan mechanism

NASA Technical Reports Server (NTRS)

Williams, Ellen I.; Summers, Richard T.; Ostaszewski, Miroslaw A.

1995-01-01

A high-performance reactionless scan mirror mechanism was developed for space applications to provide thermal images of the Earth. The design incorporates a unique mechanical means of providing reactionless operation that also minimizes weight, mechanical resonance operation to minimize power, combined use of a single optical encoder to sense coarse and fine angular position, and a new kinematic mount of the mirror. A flex pivot hardware failure and current project status are discussed.

DETERMINATION OF CARBENDAZIM IN WATER BY HIGH-PERFORMANCE IMMUNOAFFINITY CHROMATOGRAPHY ON-LINE WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH DIODE-ARRAY OR MASS SPECTROMETRIC DETECTION

EPA Science Inventory

An automated method for the determination of carbendazim in water that combines high-performance immunoaffinity chromatography (HPIAC), high-performance liquid chromatography (HPLC) in the reversed-phase mode, and detection by either UV-Vis diode array detector (DAD) spectroscopy...

Life-cycle costs of high-performance cells

NASA Technical Reports Server (NTRS)

Daniel, R.; Burger, D.; Reiter, L.

1985-01-01

A life cycle cost analysis of high efficiency cells was presented. Although high efficiency cells produce more power, they also cost more to make and are more susceptible to array hot-spot heating. Three different computer analysis programs were used: SAMICS (solar array manufacturing industry costing standards), PVARRAY (an array failure mode/degradation simulator), and LCP (lifetime cost and performance). The high efficiency cell modules were found to be more economical in this study, but parallel redundancy is recommended.

Progress on high-performance rapid prototype aluminum mirrors

NASA Astrophysics Data System (ADS)

Woodard, Kenneth S.; Myrick, Bruce H.

2017-05-01

Near net shape parts can be produced using some very old processes (investment casting) and the relatively new direct metal laser sintering (DMLS) process. These processes have significant advantages for complex blank lightweighting and costs but are not inherently suited for producing high performance mirrors. The DMLS process can provide extremely complex lightweight structures but the high residual stresses left in the material results in unstable mirror figure retention. Although not to the extreme intricacy of DMLS, investment casting can also provide complex lightweight structures at considerably lower costs than DMLS and even conventional wrought mirror blanks but the less than 100% density for casting (and also DMLS) limits finishing quality. This paper will cover the progress that has been made to make both the DMLS and investment casting processes into viable near net shape blank options for high performance aluminum mirrors. Finish and figure results will be presented to show performance commensurate with existing conventional processes.

Porous Graphene Microflowers for High-Performance Microwave Absorption

NASA Astrophysics Data System (ADS)

Chen, Chen; Xi, Jiabin; Zhou, Erzhen; Peng, Li; Chen, Zichen; Gao, Chao

2018-06-01

Graphene has shown great potential in microwave absorption (MA) owing to its high surface area, low density, tunable electrical conductivity and good chemical stability. To fully realize graphene's MA ability, the microstructure of graphene should be carefully addressed. Here we prepared graphene microflowers (Gmfs) with highly porous structure for high-performance MA filler material. The efficient absorption bandwidth (reflection loss ≤ -10 dB) reaches 5.59 GHz and the minimum reflection loss is up to -42.9 dB, showing significant increment compared with stacked graphene. Such performance is higher than most graphene-based materials in the literature. Besides, the low filling content (10 wt%) and low density (40-50 mg cm-3) are beneficial for the practical applications. Without compounding with magnetic materials or conductive polymers, Gmfs show outstanding MA performance with the aid of rational microstructure design. Furthermore, Gmfs exhibit advantages in facile processibility and large-scale production compared with other porous graphene materials including aerogels and foams.

Sleep, recovery, and performance: the new frontier in high-performance athletics.

PubMed

Samuels, Charles

2008-02-01

The relationship of sleep to post-exercise recovery (PER) and athletic performance is a topic of great interest because of the growing body of scientific evidence confirming a link between critical sleep factors, cognitive processes, and metabolic function. Sleep restriction (sleep deprivation), sleep disturbance (poor sleep quality), and circadian rhythm disturbance (jet lag) are the key sleep factors that affect the overall restorative quality of the sleep state. This article discusses these theoretic concepts, presents relevant clinical cases, and reviews pilot data exploring the prevalence of sleep disturbance in two groups of high-performance athletes.

High-performance large-area AMLCD avionic display module

NASA Astrophysics Data System (ADS)

Syroid, Daniel D.; Hansen, Glenn A.

1995-06-01

There is a need for a reliable source of high performance large area sunlight readable active matrix liquid crystal displays (AMLCDs) for avionic and military land vehicle applications. Image Quest has developed an avionic display module (ADM) to demonstrate the capability to produce high performance avionic displays to satisfy this need. The ADM is a large area (6.24 X 8.32 inch) display with VGA compatible interface, 640 X 480 color pixels and 64 gray shades per primary color. The display features excellent color discrimination in full sunlight due to a saturated color gamut, very low specular reflectance (< 1%) and high output white luminance (200 fL). The ADM is designed from the glass up to fully meet the avionic and military application and environment. Control over all the display performance parameters including contrast, transmission, chroma, resolution, active size and packaging configuration is ensured because Image Quest produces all of the critical elements of the display. These elements include the a-Si TFT AMLCD glass, RGB color filter matrix, bonding of folded back driver TABs, anti-reflective cover glass, LC heater and integration of high luminance hot cathode backlight with thermal controls. The display features rugged compact packaging, 2000:1 luminance dimming range and wide operating temperature range (-40 to +71 $DRGC). In the immediate future Image Quest plans to expand the development efforts to other similar custom high resolution and high performance avionic display module configurations including 4 X 4 inch delta triad, 6.7 X 6.7 inch delta triad and 16.5 inch diagonal with 1280 X 1024 pixels. Image Quest can deliver up to 10,000 displays per year on a timely basis at a reasonable cost.

High Performance Schools--It's a No-Brainer.

ERIC Educational Resources Information Center

Nicklas, Mike

2002-01-01

A North Carolina middle school demonstrates that high performance, sustainable school buildings cost no more to build and are more comfortable and productive learning environments than conventional buildings. (Author)

High performance light-colored nitrile-butadiene rubber nanocomposites.

PubMed

Lei, Yanda; Guo, Baochun; Chen, Feng; Zhu, Lixin; Zhou, Wenyou; Jia, Demin

2011-12-01

High mechanical performance nitrile-butadiene rubber (NBR) with light color was fabricated by the method of in situ formation of zinc disorbate (ZDS) or magnesium disorbate (MDS). The in situ formed ZDS and its polymerization via internal mixing was confirmed by X-ray diffaraction. The mechanical properties, ageing resistance, morphology and the dynamic mechanical analysis were fully studied. It was found that with increasing loading of metallic disorbate both the curing rate and the ionic crosslink density was largely increased. The modulus, tensile strength and tear strength were largely increased. With a comparison between internal mixing and opening mixing, the mechanical performance for the former one was obviously better than the latter one. The high performance was ascribed to the finely dispersion nano domains with irregular shape and obscure interfacial structures. Except for the NBR vulcanizate with a high loading of MDS, the others' ageing resistance with incorporation of these two metallic disorbate was found to be good. Dynamic mechanical analysis (DMA) showed that, with increasing loading of metallic disorbate, the highly increased storage modulus above -20 degrees C, the up-shifted glass transition temperature (Tg) and the reduced mechanical loss were ascribed to strengthened interfacial interactions.

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.

Creating a High-Performance School System.

ERIC Educational Resources Information Center

Thompson, Scott

2003-01-01

Describes several critical factors of a high-performing school system such as the system holds itself accountable for the success of all its schools. Provides school district examples of critical success factors in action. Includes districts in Colorado, Washington, Texas, California, New Jersey. Discusses the role of strategic and authentic…

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.

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.

High performance forward swept wing aircraft

NASA Technical Reports Server (NTRS)

Koenig, David G. (Inventor); Aoyagi, Kiyoshi (Inventor); Dudley, Michael R. (Inventor); Schmidt, Susan B. (Inventor)

1988-01-01

A high performance aircraft capable of subsonic, transonic and supersonic speeds employs a forward swept wing planform and at least one first and second solution ejector located on the inboard section of the wing. A high degree of flow control on the inboard sections of the wing is achieved along with improved maneuverability and control of pitch, roll and yaw. Lift loss is delayed to higher angles of attack than in conventional aircraft. In one embodiment the ejectors may be advantageously positioned spanwise on the wing while the ductwork is kept to a minimum.

Energy Design Guidelines for High Performance Schools: Hot and Dry Climates.

ERIC Educational Resources Information Center

Department of Energy, Washington, DC. Office of Energy Efficiency and Renewable Energy.

This guide contains recommendations for designing high performance, energy efficient schools located in hot and dry climates. A high performance checklist for designers is included along with several case studies of projects that successfully demonstrated high performance design solutions for hot and dry climates. The guide's 10 sections…

High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

DOE PAGES

Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

2014-07-28

The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable ofmore » handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.« less

High performance direct methanol fuel cell with thin electrolyte membrane

NASA Astrophysics Data System (ADS)

Wan, Nianfang

2017-06-01

A high performance direct methanol fuel cell is achieved with thin electrolyte membrane. 320 mW cm-2 of peak power density and over 260 mW cm-2 at 0.4 V are obtained when working at 90 °C with normal pressure air supply. It is revealed that the increased anode half-cell performance with temperature contributes primarily to the enhanced performance at elevated temperature. From the comparison of iR-compensated cathode potential of methanol/air with that of H2/air fuel cell, the impact of methanol crossover on cathode performance decreases with current density and becomes negligible at high current density. Current density is found to influence fuel efficiency and methanol crossover significantly from the measurement of fuel efficiency at different current density. At high current density, high fuel efficiency can be achieved even at high temperature, indicating decreased methanol crossover.

An Empirical Examination of the Mechanisms Mediating between High-Performance Work Systems and the Performance of Japanese Organizations

ERIC Educational Resources Information Center

Takeuchi, Riki; Lepak, David P.; Wang, Heli; Takeuchi, Kazuo

2007-01-01

The resource-based view of the firm and social exchange perspectives are invoked to hypothesize linkages among high-performance work systems, collective human capital, the degree of social exchange in an establishment, and establishment performance. The authors argue that high-performance work systems generate a high level of collective human…

High performance thermal imaging for the 21st century

NASA Astrophysics Data System (ADS)

Clarke, David J.; Knowles, Peter

2003-01-01

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

The impact of mirrors on body image and performance in high and low performing female ballet students.

PubMed

Radell, Sally A; Adame, Daniel D; Cole, Steven P; Blumenkehl, Nicole J

2011-09-01

This study assesses the effect of mirrors on body image and performance in high and low performing female collegiate ballet students. Twenty-three females enrolled in a beginning ballet class were taught using mirrors, and a second group of 23 beginning females were taught without mirrors. All participants completed the Cash 69-item Body Self-Relations Questionnaire during the first and last class of a 14-week semester. They were videotaped performing in the studio during the fifth and fourteenth weeks. Two ballet teachers independently viewed the videotapes to evaluate the dancers' rhythmic accuracy, ease and flow of movement, and mastery of steps and alignment, and rated the students' skill level on a 1-5 scale. For analysis purposes, students whose scores averaged three or higher were categorized as "high performers," and those who averaged less than three were "low performers." Two (mirror, non-mirror) by two (high performance, low performance) by two (pre-test, post-test) repeated measures ANOVAs were used to test class differences over the course of the semester. There were significant 3-way interactions for overweight preoccupation (p < 0.01) and body-areas satisfaction (p < 0.05). Low performers increased in overweight preoccupation in the non-mirror class while decreasing in the mirror class. High performers significantly increased in satisfaction for most areas of their body in the non-mirror class, while there were smaller increases for both low and high performers in the mirror class. It is concluded that while use of the mirror has some benefits in training, higher performing dancers feel better about their body image when they do not use the mirror. Lower performers who use the mirror worry less about their weight; those who do not use the mirror worry more. The mirror may provide feedback that helps low performing dancers feel more comfortable with their weight.

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.

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinomura, A., E-mail: a.kinomura@aist.go.jp; Suzuki, R.; Oshima, N.

2014-12-15

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at amore » pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO{sub 2} layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.« less

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Kinomura, A.; Suzuki, R.; Oshima, N.; O'Rourke, B. E.; Nishijima, T.; Ogawa, H.

2014-12-01

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at a pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO2 layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.

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.

High School Employment, School Performance, and College Entry

ERIC Educational Resources Information Center

Lee, Chanyoung; Orazem, Peter F.

2010-01-01

The proportion of U.S. high school students working during the school year ranges from 23% in the freshman year to 75% in the senior year. This study estimates how cumulative work histories during the high school years affect probability of dropout, high school academic performance, and the probability of attending college. Variations in…

The 2014 Michigan Public High School Context and Performance Report Card

ERIC Educational Resources Information Center

Spalding, Audrey

2014-01-01

The 2014 Michigan Public High School Context and Performance Report Card is the Mackinac Center's second effort to measure high school performance. The first high school assessment was published in 2012, followed by the Center's 2013 elementary and middle school report card, which used a similar methodology to evaluate school performance. The…

Performance evaluation of high modulus asphalt concrete mixes

NASA Astrophysics Data System (ADS)

Haritonovs, V.; Tihonovs, J.; Zaumanis, M.

2016-04-01

Dolomite is one of the most available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality (mainly, LA index). Therefore, mostly imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance to EN 13108-1 standard.

Principals' Perceptions of Professional Development in High- and Low-Performing High-Poverty Schools

ERIC Educational Resources Information Center

Moore, Sheila; Kochan, Frances

2013-01-01

This is the second part of a two-part study examining issues related to professional development in high-poverty schools. The findings from the initial study indicated that principals in high-poverty, high-performing schools perceived higher levels of implementation of quality professional development standards in their schools than did principals…

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.

High-definition television evaluation for remote handling task performance

NASA Astrophysics Data System (ADS)

Fujita, Y.; Omori, E.; Hayashi, S.; Draper, J. V.; Herndon, J. N.

Described are experiments designed to evaluate the impact of HDTV (High-Definition Television) on the performance of typical remote tasks. The experiments described in this paper compared the performance of four operators using HDTV with their performance while using other television systems. The experiments included four television systems: (1) high-definition color television, (2) high-definition monochromatic television, (3) standard-resolution monochromatic television, and (4) standard-resolution stereoscopic monochromatic television. The stereo system accomplished stereoscopy by displaying two cross-polarized images, one reflected by a half-silvered mirror and one seen through the mirror. Observers wore spectacles with cross-polarized lenses so that the left eye received only the view from the left camera and the right eye received only the view from the right camera.

High-performance nanostructured supercapacitors on a sponge.

PubMed

Chen, Wei; Rakhi, R B; Hu, Liangbing; Xie, Xing; Cui, Yi; Alshareef, H N

2011-12-14

A simple and scalable method has been developed to fabricate nanostructured MnO2-carbon nanotube (CNT)-sponge hybrid electrodes. A novel supercapacitor, henceforth referred to as "sponge supercapacitor", has been fabricated using these hybrid electrodes with remarkable performance. A specific capacitance of 1,230 F/g (based on the mass of MnO2) can be reached. Capacitors based on CNT-sponge substrates (without MnO2) can be operated even under a high scan rate of 200 V/s, and they exhibit outstanding cycle performance with only 2% degradation after 100,000 cycles under a scan rate of 10 V/s. The MnO2-CNT-sponge supercapacitors show only 4% of degradation after 10,000 cycles at a charge-discharge specific current of 5 A/g. The specific power and energy of the MnO2-CNT-sponge supercapacitors are high with values of 63 kW/kg and 31 Wh/kg, respectively. The attractive performances exhibited by these sponge supercapacitors make them potentially promising candidates for future energy storage systems.

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.

EPDM - Silicone blends - a high performance elastomeric composition for automotive applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, J.M.

1987-01-01

Styling and design changes have dramatically altered performance requirements for elastomers. High performance engines with electronic fuel injection have increased temperatures under the hood. Therefore, high performance elastomers are required to meet today's service conditions. New technology has been developed to compatibilize EPDM and silicone into high performance elastomeric compositions. These blends have physical, electrical and mechanical properties, for 175/sup 0/C service. Formulations are discussed for applications which require heat and weather resistance.

High Performance OLED Panel and Luminaire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spindler, Jeffrey

2017-02-20

In this project, OLEDWorks developed and demonstrated the technology required to produce OLED lighting panels with high energy efficiency and excellent light quality. OLED panels developed in this program produce high quality warm white light with CRI greater than 85 and efficacy up to 80 lumens per watt (LPW). An OLED luminaire employing 24 of the high performance panels produces practical levels of illumination for general lighting, with a flux of over 2200 lumens at 60 LPW. This is a significant advance in the state of the art for OLED solid-state lighting (SSL), which is expected to be a complementarymore » light source to the more advanced LED SSL technology that is rapidly replacing all other traditional forms of lighting.« less

High-performance computing for airborne applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinn, Heather M; Manuzzato, Andrea; Fairbanks, Tom

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 thoughmore » 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.« less

High- and Reproducible-Performance Graphene/II-VI Semiconductor Film Hybrid Photodetectors

PubMed Central

Huang, Fan; Jia, Feixiang; Cai, Caoyuan; Xu, Zhihao; Wu, Congjun; Ma, Yang; Fei, Guangtao; Wang, Min

2016-01-01

High- and reproducible-performance photodetectors are critical to the development of many technologies, which mainly include one-dimensional (1D) nanostructure based and film based photodetectors. The former suffer from a huge performance variation because the performance is quite sensitive to the synthesis microenvironment of 1D nanostructure. Herein, we show that the graphene/semiconductor film hybrid photodetectors not only possess a high performance but also have a reproducible performance. As a demo, the as-produced graphene/ZnS film hybrid photodetector shows a high responsivity of 1.7 × 107 A/W and a fast response speed of 50 ms, and shows a highly reproducible performance, in terms of narrow distribution of photocurrent (38–65 μA) and response speed (40–60 ms) for 20 devices. Graphene/ZnSe film and graphene/CdSe film hybrid photodetectors fabricated by this method also show a high and reproducible performance. The general method is compatible with the conventional planar process, and would be easily standardized and thus pay a way for the photodetector applications. PMID:27349692

High-Speed 3D Printing of High-Performance Thermosetting Polymers via Two-Stage Curing.

PubMed

Kuang, Xiao; Zhao, Zeang; Chen, Kaijuan; Fang, Daining; Kang, Guozheng; Qi, Hang Jerry

2018-04-01

Design and direct fabrication of high-performance thermosets and composites via 3D printing are highly desirable in engineering applications. Most 3D printed thermosetting polymers to date suffer from poor mechanical properties and low printing speed. Here, a novel ink for high-speed 3D printing of high-performance epoxy thermosets via a two-stage curing approach is presented. The ink containing photocurable resin and thermally curable epoxy resin is used for the digital light processing (DLP) 3D printing. After printing, the part is thermally cured at elevated temperature to yield an interpenetrating polymer network epoxy composite, whose mechanical properties are comparable to engineering epoxy. The printing speed is accelerated by the continuous liquid interface production assisted DLP 3D printing method, achieving a printing speed as high as 216 mm h -1 . It is also demonstrated that 3D printing structural electronics can be achieved by combining the 3D printed epoxy composites with infilled silver ink in the hollow channels. The new 3D printing method via two-stage curing combines the attributes of outstanding printing speed, high resolution, low volume shrinkage, and excellent mechanical properties, and provides a new avenue to fabricate 3D thermosetting composites with excellent mechanical properties and high efficiency toward high-performance and functional applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improved confinement in highly powered high performance scenarios on DIII-D

NASA Astrophysics Data System (ADS)

Petrie, T. W.; Osborne, T.; Fenstermacher, M. E.; Ferron, J.; Groebner, R.; Grierson, B.; Holcomb, C.; Lasnier, C.; Leonard, A.; Luce, T.; Makowski, M.; Turco, F.; Solomon, W.; Victor, B.; Watkins, J.

2017-08-01

DIII-D has recently demonstrated improved energy confinement by injecting neutral deuterium gas into high performance near-double null divertor (DND) plasmas during high power operation. Representative parameters for these plasmas are: q 95  =  6, P IN up to 15 MW, H 98  =  1.4-1.8, and β N  =  2.5-4.0. The ion B   ×  \

Experimental Performance of a Micromachined Heat Flux Sensor

NASA Technical Reports Server (NTRS)

Stefanescu, S.; DeAnna, R. G.; Mehregany, M.

1998-01-01

Steady-state and frequency response calibration of a microfabricated heat-flux sensor have been completed. This sensor is batch fabricated using standard, micromachining techniques, allowing both miniaturization and the ability to create arrays of sensors and their corresponding interconnects. Both high-frequency and spatial response is desired, so the sensors are both thin and of small cross-sectional area. Thin-film, temperature-sensitive resistors are used as the active gauge elements. Two sensor configurations are investigated: (1) a Wheatstone-bridge using four resistors; and (2) a simple, two-resistor design. In each design, one resistor (or pair) is covered by a thin layer (5000 A) thermal barrier; the other resistor (or pair) is covered by a thick (5 microns) thermal barrier. The active area of a single resistor is 360 microns by 360 microns; the total gauge area is 1.5 mm square. The resistors are made of 2000 A-thick metal; and the entire gauge is fabricated on a 25 microns-thick flexible, polyimide substrate. Heat flux through the surface changes the temperature of the resistors and produces a corresponding change in resistance. Sensors were calibrated using two radiation heat sources: (1) a furnace for steady-state, and (2) a light and chopper for frequency response.

Support Expressed in Congress for U.S. High-Performance Computing

NASA Astrophysics Data System (ADS)

Showstack, Randy

2004-06-01

Advocates for a stronger U.S. position in high-performance computing-which could help with a number of grand challenges in the Earth sciences and other disciplines-hope that legislation recently introduced in the House of Representatives, and, will help to revitalize U.S. efforts. The High-Performance Computing Revitalization Act of 2004 would amend the earlier High-Performance Computing Act of 1991 (Public Law 102-194), which is partially credited with helping to strengthen U.S. capabilities in this area. The bill has the support of the Bush administration.

Chopper-stabilized phase detector

NASA Technical Reports Server (NTRS)

Hopkins, P. M.

1978-01-01

Phase-detector circuit for binary-tracking loops and other binary-data acquisition systems minimizes effects of drift, gain imbalance, and voltage offset in detector circuitry. Input signal passes simultaneously through two channels where it is mixed with early and late codes that are alternately switched between channels. Code switching is synchronized with polarity switching of detector output of each channel so that each channel uses each detector for half time. Net result is that dc offset errors are canceled, and effect of gain imbalance is simply change in sensitivity.

Monitoring SLAC High Performance UNIX Computing Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.more » Comparisons between data storage by both databases are made using gnuplot and Ganglia's real-time graphical user interface.« less

GPU-based High-Performance Computing for Radiation Therapy

PubMed Central

Jia, Xun; Ziegenhein, Peter; Jiang, Steve B.

2014-01-01

Recent developments in radiotherapy therapy demand high computation powers to solve challenging problems in a timely fashion in a clinical environment. Graphics processing unit (GPU), as an emerging high-performance computing platform, has been introduced to radiotherapy. It is particularly attractive due to its high computational power, small size, and low cost for facility deployment and maintenance. Over the past a few years, GPU-based high-performance computing in radiotherapy has experienced rapid developments. A tremendous amount of studies have been conducted, in which large acceleration factors compared with the conventional CPU platform have been observed. In this article, we will first give a brief introduction to the GPU hardware structure and programming model. We will then review the current applications of GPU in major imaging-related and therapy-related problems encountered in radiotherapy. A comparison of GPU with other platforms will also be presented. PMID:24486639

PuTTY | High-Performance Computing | NREL

Science.gov Websites

PuTTY PuTTY Learn how to use PuTTY to connect to NREL's high-performance computing (HPC) systems . Connecting When you start the PuTTY app, the program will display PuTTY's Configuration menu. When this comes . When prompted, type your password again followed by . Note: to increase

Blocking Student Performance in High School?

ERIC Educational Resources Information Center

Hughes, Woodrow, W., Jr.

2004-01-01

Block schedules have been used in several different high schools in various areas of the United States. Reasons for their use vary from better preparing students for college work to fewer disruptions of the school day. Several studies have examined the impact of changing from a semester system to a block system on the academic performance in…

Student Performance Standards for Senior High Language Arts.

ERIC Educational Resources Information Center

Brevard County School Board, Cocoa, FL.

Developed by a team of 13 teachers, this guide presents student performance standards for 36 high school language arts courses. For each course described, performance standards and intended outcomes are preceded by a curriculum framework that includes a statement of major concepts and content, laboratory activities, special notes, and intended…

Two Profiles of the Dutch High Performing Employee

ERIC Educational Resources Information Center

de Waal, A. A.; Oudshoorn, Michella

2015-01-01

Purpose: The purpose of this study is to explore the profile of an ideal employee, to be more precise the behavioral characteristics of the Dutch high-performing employee (HPE). Organizational performance depends for a large part on the commitment of employees. Employees provide their knowledge, skills, experiences and creativity to the…

High Performance Computing Software Applications for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Giuliano, C.; Schumacher, P.; Matson, C.; Chun, F.; Duncan, B.; Borelli, K.; Desonia, R.; Gusciora, G.; Roe, K.

The High Performance Computing Software Applications Institute for Space Situational Awareness (HSAI-SSA) has completed its first full year of applications development. The emphasis of our work in this first year was in improving space surveillance sensor models and image enhancement software. These applications are the Space Surveillance Network Analysis Model (SSNAM), the Air Force Space Fence simulation (SimFence), and physically constrained iterative de-convolution (PCID) image enhancement software tool. Specifically, we have demonstrated order of magnitude speed-up in those codes running on the latest Cray XD-1 Linux supercomputer (Hoku) at the Maui High Performance Computing Center. The software applications improvements that HSAI-SSA has made, has had significant impact to the warfighter and has fundamentally changed the role of high performance computing in SSA.

Lanczos eigensolution method for high-performance computers

NASA Technical Reports Server (NTRS)

Bostic, Susan W.

1991-01-01

The theory, computational analysis, and applications are presented of a Lanczos algorithm on high performance computers. The computationally intensive steps of the algorithm are identified as: the matrix factorization, the forward/backward equation solution, and the matrix vector multiples. These computational steps are optimized to exploit the vector and parallel capabilities of high performance computers. The savings in computational time from applying optimization techniques such as: variable band and sparse data storage and access, loop unrolling, use of local memory, and compiler directives are presented. Two large scale structural analysis applications are described: the buckling of a composite blade stiffened panel with a cutout, and the vibration analysis of a high speed civil transport. The sequential computational time for the panel problem executed on a CONVEX computer of 181.6 seconds was decreased to 14.1 seconds with the optimized vector algorithm. The best computational time of 23 seconds for the transport problem with 17,000 degs of freedom was on the the Cray-YMP using an average of 3.63 processors.

Efficient high-performance ultrasound beamforming using oversampling

NASA Astrophysics Data System (ADS)

Freeman, Steven R.; Quick, Marshall K.; Morin, Marc A.; Anderson, R. C.; Desilets, Charles S.; Linnenbrink, Thomas E.; O'Donnell, Matthew

1998-05-01

High-performance and efficient beamforming circuitry is very important in large channel count clinical ultrasound systems. Current state-of-the-art digital systems using multi-bit analog to digital converters (A/Ds) have matured to provide exquisite image quality with moderate levels of integration. A simplified oversampling beamforming architecture has been proposed that may a low integration of delta-sigma A/Ds onto the same chip as digital delay and processing circuitry to form a monolithic ultrasound beamformer. Such a beamformer may enable low-power handheld scanners for high-end systems with very large channel count arrays. This paper presents an oversampling beamformer architecture that generates high-quality images using very simple; digitization, delay, and summing circuits. Additional performance may be obtained with this oversampled system for narrow bandwidth excitations by mixing the RF signal down in frequency to a range where the electronic signal to nose ratio of the delta-sigma A/D is optimized. An oversampled transmit beamformer uses the same delay circuits as receive and eliminates the need for separate transmit function generators.

Designing 3D highly ordered nanoporous CuO electrodes for high-performance asymmetric supercapacitors.

PubMed

Moosavifard, Seyyed E; El-Kady, Maher F; Rahmanifar, Mohammad S; Kaner, Richard B; Mousavi, Mir F

2015-03-04

The increasing demand for energy has triggered tremendous research efforts for the development of lightweight and durable energy storage devices. Herein, we report a simple, yet effective, strategy for high-performance supercapacitors by building three-dimensional pseudocapacitive CuO frameworks with highly ordered and interconnected bimodal nanopores, nanosized walls (∼4 nm) and large specific surface area of 149 m(2) g(-1). This interesting electrode structure plays a key role in providing facilitated ion transport, short ion and electron diffusion pathways and more active sites for electrochemical reactions. This electrode demonstrates excellent electrochemical performance with a specific capacitance of 431 F g(-1) (1.51 F cm(-2)) at 3.5 mA cm(-2) and retains over 70% of this capacitance when operated at an ultrafast rate of 70 mA cm(-2). When this highly ordered CuO electrode is assembled in an asymmetric cell with an activated carbon electrode, the as-fabricated device demonstrates remarkable performance with an energy density of 19.7 W h kg(-1), power density of 7 kW kg(-1), and excellent cycle life. This work presents a new platform for high-performance asymmetric supercapacitors for the next generation of portable electronics and electric vehicles.

A high-performance channel engineered charge-plasma-based MOSFET with high-κ spacer

NASA Astrophysics Data System (ADS)

Shan, Chan; Wang, Ying; Luo, Xin; Bao, Meng-tian; Yu, Cheng-hao; Cao, Fei

2017-12-01

In this paper, the performance of graded channel double-gate MOSFET (GC-DGFET) that utilizes the charge-plasma concept and a high-κ spacer is investigated through 2-D device simulations. The results demonstrate that GC-DGFET with high-κ spacer can effectively improve the ON-state driving current (ION) and reduce the OFF-leakage current (IOFF). We find that reduction of the initial energy barrier between the source and channel is the origin of this ION enhancement. The reason for the IOFF reduction is identified to be the extension of the effective channel length owing to the fringing field via high-κ spacers. Consequently, these devices offer enhanced performance by reducing the total gate-to-gate capacitance (Cgg) and decreasing the intrinsic delay (τ).

High-performance wireless powering for peripheral nerve neuromodulation systems

PubMed Central

Liu, Jiayin; Liao, Song-Yan; Zhen, Zhe; Hsu, Stephanie; Shuto, Chika; Zhu, Zi-Yi; Ma, Andrew; Vassos, Christopher; Chen, Peter; Tse, Hung Fat; Poon, Ada S. Y.

2017-01-01

Neuromodulation of peripheral nerves with bioelectronic devices is a promising approach for treating a wide range of disorders. Wireless powering could enable long-term operation of these devices, but achieving high performance for miniaturized and deeply placed devices remains a technological challenge. We report the miniaturized integration of a wireless powering system in soft neuromodulation device (15 mm length, 2.7 mm diameter) and demonstrate high performance (about 10%) during in vivo wireless stimulation of the vagus nerve in a porcine animal model. The increased performance is enabled by the generation of a focused and circularly polarized field that enhances efficiency and provides immunity to polarization misalignment. These performance characteristics establish the clinical potential of wireless powering for emerging therapies based on neuromodulation. PMID:29065141

High-performance wireless powering for peripheral nerve neuromodulation systems.

PubMed

Tanabe, Yuji; Ho, John S; Liu, Jiayin; Liao, Song-Yan; Zhen, Zhe; Hsu, Stephanie; Shuto, Chika; Zhu, Zi-Yi; Ma, Andrew; Vassos, Christopher; Chen, Peter; Tse, Hung Fat; Poon, Ada S Y

2017-01-01

Neuromodulation of peripheral nerves with bioelectronic devices is a promising approach for treating a wide range of disorders. Wireless powering could enable long-term operation of these devices, but achieving high performance for miniaturized and deeply placed devices remains a technological challenge. We report the miniaturized integration of a wireless powering system in soft neuromodulation device (15 mm length, 2.7 mm diameter) and demonstrate high performance (about 10%) during in vivo wireless stimulation of the vagus nerve in a porcine animal model. The increased performance is enabled by the generation of a focused and circularly polarized field that enhances efficiency and provides immunity to polarization misalignment. These performance characteristics establish the clinical potential of wireless powering for emerging therapies based on neuromodulation.

Signal Processing, Pattern Formation and Adaptation in Neural Oscillators

DTIC Science & Technology

2016-11-29

nonlinear oscillations of outer hair cells. We obtained analytical forms for auditory tuning curves of both unidirectionally and bidirectionally coupled...oscillations of outer hair cells in the cochlea, mode-locking of chopper cells to sound in the cochlear nucleus, and entrainment of cortical...oscillations of outer hair cells (e.g., Fredrickson-Hemsing, Ji, Bruinsma, & Bozovic, 2012), mode-locking of choppers in the cochlear nucleus (e.g., Laudanski

Internal curing of high-performance concrete for bridge decks.

DOT National Transportation Integrated Search

2013-03-01

High performance concrete (HPC) provides a long lasting, durable concrete that is typically used in bridge decks due to its low permeability, high abrasion resistance, freeze-thaw resistance and strength. However, this type of concrete is highly susc...

Building and measuring a high performance network architecture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kramer, William T.C.; Toole, Timothy; Fisher, Chuck

2001-04-20

Once a year, the SC conferences present a unique opportunity to create and build one of the most complex and highest performance networks in the world. At SC2000, large-scale and complex local and wide area networking connections were demonstrated, including large-scale distributed applications running on different architectures. This project was designed to use the unique opportunity presented at SC2000 to create a testbed network environment and then use that network to demonstrate and evaluate high performance computational and communication applications. This testbed was designed to incorporate many interoperable systems and services and was designed for measurement from the very beginning.more » The end results were key insights into how to use novel, high performance networking technologies and to accumulate measurements that will give insights into the networks of the future.« less

A High Performance Block Eigensolver for Nuclear Configuration Interaction Calculations

DOE PAGES

Aktulga, Hasan Metin; Afibuzzaman, Md.; Williams, Samuel; ...

2017-06-01

As on-node parallelism increases and the performance gap between the processor and the memory system widens, achieving high performance in large-scale scientific applications requires an architecture-aware design of algorithms and solvers. We focus on the eigenvalue problem arising in nuclear Configuration Interaction (CI) calculations, where a few extreme eigenpairs of a sparse symmetric matrix are needed. Here, we consider a block iterative eigensolver whose main computational kernels are the multiplication of a sparse matrix with multiple vectors (SpMM), and tall-skinny matrix operations. We then present techniques to significantly improve the SpMM and the transpose operation SpMM T by using themore » compressed sparse blocks (CSB) format. We achieve 3-4× speedup on the requisite operations over good implementations with the commonly used compressed sparse row (CSR) format. We develop a performance model that allows us to correctly estimate the performance of our SpMM kernel implementations, and we identify cache bandwidth as a potential performance bottleneck beyond DRAM. We also analyze and optimize the performance of LOBPCG kernels (inner product and linear combinations on multiple vectors) and show up to 15× speedup over using high performance BLAS libraries for these operations. The resulting high performance LOBPCG solver achieves 1.4× to 1.8× speedup over the existing Lanczos solver on a series of CI computations on high-end multicore architectures (Intel Xeons). We also analyze the performance of our techniques on an Intel Xeon Phi Knights Corner (KNC) processor.« less

A High Performance Block Eigensolver for Nuclear Configuration Interaction Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aktulga, Hasan Metin; Afibuzzaman, Md.; Williams, Samuel

As on-node parallelism increases and the performance gap between the processor and the memory system widens, achieving high performance in large-scale scientific applications requires an architecture-aware design of algorithms and solvers. We focus on the eigenvalue problem arising in nuclear Configuration Interaction (CI) calculations, where a few extreme eigenpairs of a sparse symmetric matrix are needed. Here, we consider a block iterative eigensolver whose main computational kernels are the multiplication of a sparse matrix with multiple vectors (SpMM), and tall-skinny matrix operations. We then present techniques to significantly improve the SpMM and the transpose operation SpMM T by using themore » compressed sparse blocks (CSB) format. We achieve 3-4× speedup on the requisite operations over good implementations with the commonly used compressed sparse row (CSR) format. We develop a performance model that allows us to correctly estimate the performance of our SpMM kernel implementations, and we identify cache bandwidth as a potential performance bottleneck beyond DRAM. We also analyze and optimize the performance of LOBPCG kernels (inner product and linear combinations on multiple vectors) and show up to 15× speedup over using high performance BLAS libraries for these operations. The resulting high performance LOBPCG solver achieves 1.4× to 1.8× speedup over the existing Lanczos solver on a series of CI computations on high-end multicore architectures (Intel Xeons). We also analyze the performance of our techniques on an Intel Xeon Phi Knights Corner (KNC) processor.« less

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.

Co-Percolating Graphene-Wrapped Silver Nanowire Network for High Performance, Highly Stable, Transparent Conducting Electrodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ruiyi; Das, Suprem R; Jeong, Changwook

Transparent conducting electrodes (TCEs) require high transparency and low sheet resistance for applications in photovoltaics, photodetectors, flat panel displays, touch screen devices, and imagers. Indium tin oxide (ITO), or other transparent conductive oxides, have been used, and provide a baseline sheet resistance (RS) vs. transparency (T) relationship. Several alternative material systems have been investigated. The development of high-performance hybrid structures provides a route towards robust, scalable and low-cost approaches for realizing high-performance TCE.

Highly automated driving, secondary task performance, and driver state.

PubMed

Merat, Natasha; Jamson, A Hamish; Lai, Frank C H; Carsten, Oliver

2012-10-01

A driving simulator study compared the effect of changes in workload on performance in manual and highly automated driving. Changes in driver state were also observed by examining variations in blink patterns. With the addition of a greater number of advanced driver assistance systems in vehicles, the driver's role is likely to alter in the future from an operator in manual driving to a supervisor of highly automated cars. Understanding the implications of such advancements on drivers and road safety is important. A total of 50 participants were recruited for this study and drove the simulator in both manual and highly automated mode. As well as comparing the effect of adjustments in driving-related workload on performance, the effect of a secondary Twenty Questions Task was also investigated. In the absence of the secondary task, drivers' response to critical incidents was similar in manual and highly automated driving conditions. The worst performance was observed when drivers were required to regain control of driving in the automated mode while distracted by the secondary task. Blink frequency patterns were more consistent for manual than automated driving but were generally suppressed during conditions of high workload. Highly automated driving did not have a deleterious effect on driver performance, when attention was not diverted to the distracting secondary task. As the number of systems implemented in cars increases, an understanding of the implications of such automation on drivers' situation awareness, workload, and ability to remain engaged with the driving task is important.

Towards high-performance materials for road construction

NASA Astrophysics Data System (ADS)

Gladkikh, V.; Korolev, E.; Smirnov, V.

2017-10-01

Due to constant increase of traffic, modern road construction is in need of high-performance pavement materials. The operational performance of such materials can be characterized by many properties. Nevertheless, the most important ones are resistance to rutting and resistance to dynamical loads. It was proposed earlier to use sulfur extended asphalt concrete in road construction practice. To reduce the emission of sulfur dioxide and hydrogen sulfide during the concrete mix preparation and pavement production stages, it is beneficial to make such a concrete on the base of complex sulfur modifier. In the present work the influence of the complex modifier to mechanical properties of sulfur extended asphalt concrete was examined. It was shown that sulfur extended asphalt concrete is of high mechanical properties. It was also revealed that there as an anomalous negative correlations between strain capacity, fatigue life and fracture toughness.

Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

PubMed

Doshi, Gaurav Mahesh; Une, Hemant Devidas

2016-01-01

In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

PubMed Central

Doshi, Gaurav Mahesh; Une, Hemant Devidas

2016-01-01

Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

Importance of balanced architectures in the design of high-performance imaging systems

NASA Astrophysics Data System (ADS)

Sgro, Joseph A.; Stanton, Paul C.

1999-03-01

Imaging systems employed in demanding military and industrial applications, such as automatic target recognition and computer vision, typically require real-time high-performance computing resources. While high- performances computing systems have traditionally relied on proprietary architectures and custom components, recent advances in high performance general-purpose microprocessor technology have produced an abundance of low cost components suitable for use in high-performance computing systems. A common pitfall in the design of high performance imaging system, particularly systems employing scalable multiprocessor architectures, is the failure to balance computational and memory bandwidth. The performance of standard cluster designs, for example, in which several processors share a common memory bus, is typically constrained by memory bandwidth. The symptom characteristic of this problem is failure to the performance of the system to scale as more processors are added. The problem becomes exacerbated if I/O and memory functions share the same bus. The recent introduction of microprocessors with large internal caches and high performance external memory interfaces makes it practical to design high performance imaging system with balanced computational and memory bandwidth. Real word examples of such designs will be presented, along with a discussion of adapting algorithm design to best utilize available memory bandwidth.

An integrated framework for high level design of high performance signal processing circuits on FPGAs

NASA Astrophysics Data System (ADS)

Benkrid, K.; Belkacemi, S.; Sukhsawas, S.

2005-06-01

This paper proposes an integrated framework for the high level design of high performance signal processing algorithms' implementations on FPGAs. The framework emerged from a constant need to rapidly implement increasingly complicated algorithms on FPGAs while maintaining the high performance needed in many real time digital signal processing applications. This is particularly important for application developers who often rely on iterative and interactive development methodologies. The central idea behind the proposed framework is to dynamically integrate high performance structural hardware description languages with higher level hardware languages in other to help satisfy the dual requirement of high level design and high performance implementation. The paper illustrates this by integrating two environments: Celoxica's Handel-C language, and HIDE, a structural hardware environment developed at the Queen's University of Belfast. On the one hand, Handel-C has been proven to be very useful in the rapid design and prototyping of FPGA circuits, especially control intensive ones. On the other hand, HIDE, has been used extensively, and successfully, in the generation of highly optimised parameterisable FPGA cores. In this paper, this is illustrated in the construction of a scalable and fully parameterisable core for image algebra's five core neighbourhood operations, where fully floorplanned efficient FPGA configurations, in the form of EDIF netlists, are generated automatically for instances of the core. In the proposed combined framework, highly optimised data paths are invoked dynamically from within Handel-C, and are synthesized using HIDE. Although the idea might seem simple prima facie, it could have serious implications on the design of future generations of hardware description languages.

High-performance flexible microwave passives on plastic

NASA Astrophysics Data System (ADS)

Ma, Zhenqiang; Seo, Jung-Hun; Cho, Sang June; Zhou, Weidong

2014-06-01

We report the demonstration of bendable inductors, capacitors and switches fabricated on a polyethylene terephthalate (PET) substrate that can operate at high microwave frequencies. By employing bendable dielectric and single crystalline semiconductor materials, spiral inductors and metal-insulator-metal (MIM) capacitors with high quality factors and high resonance frequencies and single-pole, single-throw (SPST) switches were archived. The effects of mechanical bending on the performance of inductors, capacitors and switches were also measured and analyzed. We further investigated the highest possible resonance frequencies and quality factors of inductors and capacitors and, high frequency responses and insertion loss. These demonstrations will lead to flexible radio-frequency and microwave systems in the future.

High Performance Fatty Acid-Based Vinyl Ester Resin for Liquid Molding

DTIC Science & Technology

2007-07-01

High Performance Fatty Acid -Based Vinyl Ester Resin for Liquid Molding by Xing Geng, John J. La Scala, James M. Sands, and Giuseppe R...it to the originator. Army Research Laboratory Aberdeen Proving Ground, MD 21005-5069 ARL-RP-184 July 2007 High Performance Fatty Acid ...CONTRACT NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE High Performance Fatty Acid -Based Vinyl Ester Resin for Liquid Molding 5c. PROGRAM

Tough, high performance, addition-type thermoplastic polymers

NASA Technical Reports Server (NTRS)

Pater, Ruth H. (Inventor)

1992-01-01

A tough, high performance polyimide is provided by reacting a triple bond conjugated with an aromatic ring in a bisethynyl compound with the active double bond in a compound containing a double bond activated toward the formation of a Diels-Adler type adduct, especially a bismaleimide, a biscitraconimide, or a benzoquinone, or mixtures thereof. Addition curing of this product produces a high linear polymeric structure and heat treating the highly linear polymeric structure produces a thermally stable aromatic addition-type thermoplastic polyimide, which finds utility in the preparation of molding compounds, adhesive compositions, and polymer matrix composites.

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.

High altitude cognitive performance and COPD interaction

PubMed Central

Kourtidou-Papadeli, C; Papadelis, C; Koutsonikolas, D; Boutzioukas, S; Styliadis, C; Guiba-Tziampiri, O

2008-01-01

Introduction: Thousands of people work and perform everyday in high altitude environment, either as pilots, or shift workers, or mountaineers. The problem is that most of the accidents in this environment have been attributed to human error. The objective of this study was to assess complex cognitive performance as it interacts with respiratory insufficiency at altitudes of 8000 feet and identify the potential effect of hypoxia on safe performance. Methods: Twenty subjects participated in the study, divided in two groups: Group I with mild asymptomatic chronic obstructive pulmonary disease (COPD), and Group II with normal respiratory function. Altitude was simulated at 8000 ft. using gas mixtures. Results: Individuals with mild COPD experienced notable hypoxemia with significant performance decrements and increased number of errors at cabin altitude, compared to normal subjects, whereas their blood pressure significantly increased. PMID:19048098

42 CFR 493.25 - Laboratories performing tests of high complexity.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 5 2011-10-01 2011-10-01 false Laboratories performing tests of high complexity. 493.25 Section 493.25 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND....25 Laboratories performing tests of high complexity. (a) A laboratory must obtain a certificate for...

42 CFR 493.25 - Laboratories performing tests of high complexity.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 5 2010-10-01 2010-10-01 false Laboratories performing tests of high complexity. 493.25 Section 493.25 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND....25 Laboratories performing tests of high complexity. (a) A laboratory must obtain a certificate for...

Application of ultra-high performance concrete to bridge girders.

DOT National Transportation Integrated Search

2009-02-01

"Ultra-High Performance Concrete (UHPC) is a new class of concrete that has superior performance characteristics : compared to conventional concrete. The enhanced strength and durability properties of UHPC are mainly due to optimized : particle grada...

High performance felt-metal-wick heat pipe for solar receivers

NASA Astrophysics Data System (ADS)

Andraka, Charles E.; Moss, Timothy A.; Baturkin, Volodymyr; Zaripov, Vladlen; Nishchyk, Oleksandr

2016-05-01

Sodium heat pipes have been identified as a potentially effective heat transport approach for CSP systems that require near-isothermal input to power cycles or storage, such as dish Stirling and highly recuperated reheat-cycle supercritical CO2 turbines. Heat pipes offer high heat flux capabilities, leading to small receivers, as well as low exergetic losses through isothermal coupling with the engine. Sandia developed a felt metal wick approach in the 1990's, and demonstrated very high performance1. However, multiple durability issues arose, primarily the structural collapse of the wick at temperature over short time periods. NTUU developed several methods of improving robustness of the wick2, but the resulting wick had limited performance capabilities. For application to CSP systems, the wick structures must retain high heat pipe performance with robustness for long term operation. In this paper we present our findings in developing an optimal balance between performance and ruggedness, including operation of a laboratory-scale heat pipe for over 5500 hours so far. Application of heat pipes to dish-Stirling systems has been shown to increase performance as much as 20%3, and application to supercritical CO2 systems has been proposed.

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dufresne, Eric M.; Dunford, Robert W.; Kanter, Elliot P.

The performance of a cooled Be compound refractive lens (CRL) has been tested at the Advanced Photon Source (APS) to enable vertical focusing of the pink beam and permit the X-ray beam to spatially overlap with an 80 µm-high low-density plasma that simulates astrophysical environments. Focusing the fundamental harmonics of an insertion device white beam increases the APS power density; here, a power density as high as 500 W mm –2 was calculated. A CRL is chromatic so it does not efficiently focus X-rays whose energies are above the fundamental. Only the fundamental of the undulator focuses at the experiment.more » A two-chopper system reduces the power density on the imaging system and lens by four orders of magnitude, enabling imaging of the focal plane without any X-ray filter. As a result, a method to measure such high power density as well as the performance of the lens in focusing the pink beam is reported.« less

Pink-beam focusing with a one-dimensional compound refractive lens

DOE PAGES

Dufresne, Eric M.; Dunford, Robert W.; Kanter, Elliot P.; ...

2016-07-28

The performance of a cooled Be compound refractive lens (CRL) has been tested at the Advanced Photon Source (APS) to enable vertical focusing of the pink beam and permit the X-ray beam to spatially overlap with an 80 µm-high low-density plasma that simulates astrophysical environments. Focusing the fundamental harmonics of an insertion device white beam increases the APS power density; here, a power density as high as 500 W mm –2 was calculated. A CRL is chromatic so it does not efficiently focus X-rays whose energies are above the fundamental. Only the fundamental of the undulator focuses at the experiment.more » A two-chopper system reduces the power density on the imaging system and lens by four orders of magnitude, enabling imaging of the focal plane without any X-ray filter. As a result, a method to measure such high power density as well as the performance of the lens in focusing the pink beam is reported.« less

42 CFR 493.25 - Laboratories performing tests of high complexity.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 5 2014-10-01 2014-10-01 false Laboratories performing tests of high complexity. 493.25 Section 493.25 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STANDARDS AND CERTIFICATION LABORATORY REQUIREMENTS General Provisions § 493.25 Laboratories performing tests of high...

Unlocking the Black Box: Exploring the Link between High-Performance Work Systems and Performance

ERIC Educational Resources Information Center

Messersmith, Jake G.; Patel, Pankaj C.; Lepak, David P.

2011-01-01

With a growing body of literature linking systems of high-performance work practices to organizational performance outcomes, recent research has pushed for examinations of the underlying mechanisms that enable this connection. In this study, based on a large sample of Welsh public-sector employees, we explored the role of several individual-level…

Chaining for Flexible and High-Performance Key-Value Systems

DTIC Science & Technology

2012-09-01

store that is fault tolerant achieves high performance and availability, and offers strong data consistency? We present a new replication protocol...effective high performance data access and analytics, many sites use simpler data model “ NoSQL ” systems. ese systems store and retrieve data only by...DRAM, Flash, and disk-based storage; can act as an unreliable cache or a durable store ; and can offer strong or weak data consistency. e value of

High-Performance I/O: HDF5 for Lattice QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurth, Thorsten; Pochinsky, Andrew; Sarje, Abhinav

2015-01-01

Practitioners of lattice QCD/QFT have been some of the primary pioneer users of the state-of-the-art high-performance-computing systems, and contribute towards the stress tests of such new machines as soon as they become available. As with all aspects of high-performance-computing, I/O is becoming an increasingly specialized component of these systems. In order to take advantage of the latest available high-performance I/O infrastructure, to ensure reliability and backwards compatibility of data files, and to help unify the data structures used in lattice codes, we have incorporated parallel HDF5 I/O into the SciDAC supported USQCD software stack. Here we present the design andmore » implementation of this I/O framework. Our HDF5 implementation outperforms optimized QIO at the 10-20% level and leaves room for further improvement by utilizing appropriate dataset chunking.« less

High-Performance I/O: HDF5 for Lattice QCD

DOE PAGES

Kurth, Thorsten; Pochinsky, Andrew; Sarje, Abhinav; ...

2017-05-09

Practitioners of lattice QCD/QFT have been some of the primary pioneer users of the state-of-the-art high-performance-computing systems, and contribute towards the stress tests of such new machines as soon as they become available. As with all aspects of high-performance-computing, I/O is becoming an increasingly specialized component of these systems. In order to take advantage of the latest available high-performance I/O infrastructure, to ensure reliability and backwards compatibility of data files, and to help unify the data structures used in lattice codes, we have incorporated parallel HDF5 I/O into the SciDAC supported USQCD software stack. Here we present the design andmore » implementation of this I/O framework. Our HDF5 implementation outperforms optimized QIO at the 10-20% level and leaves room for further improvement by utilizing appropriate dataset chunking.« less

Micro-polarimeter for high performance liquid chromatography

DOEpatents

Yeung, Edward E.; Steenhoek, Larry E.; Woodruff, Steven D.; Kuo, Jeng-Chung

1985-01-01

A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

Ideation High Performers: A Study of Motivational Factors

ERIC Educational Resources Information Center

Bergendahl, Magnus; Magnusson, Mats; Björk, Jennie

2015-01-01

As innovation today is one of the keys to success for firms, creativity among employees becomes an important asset and the understanding about what motivates employees in ideation is consequently of high interest. This article addresses differences in motivation among high and low performers in ideation and contributes to existing theory by…

Development of high-performance blended cements

NASA Astrophysics Data System (ADS)

Wu, Zichao

2000-10-01

This thesis presents the development of high-performance blended cements from industrial by-products. To overcome the low-early strength of blended cements, several chemicals were studied as the activators for cement hydration. Sodium sulfate was discovered as the best activator. The blending proportions were optimized by Taguchi experimental design. The optimized blended cements containing up to 80% fly ash performed better than Type I cement in strength development and durability. Maintaining a constant cement content, concrete produced from the optimized blended cements had equal or higher strength and higher durability than that produced from Type I cement alone. The key for the activation mechanism was the reaction between added SO4 2- and Ca2+ dissolved from cement hydration products.

High Temperature Steam Electrolysis: Demonstration of Improved Long-Term Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. E. O'Brien; X. Zhang; R. C. O'Brien

2011-11-01

Long-term performance is an ongoing issue for hydrogen production based on high-temperature steam electrolysis (HTSE). For commercial deployment, solid-oxide electrolysis stacks must achieve high performance with long-term degradation rates of {approx}0.5%/1000 hours or lower. Significant progress has been achieved toward this goal over the past few years. This paper will provide details of progress achieved under the Idaho National Laboratory high temperature electrolysis research program. Recent long-term stack tests have achieved high initial performance with degradation rates less than 5%/khr. These tests utilize internally manifolded stacks with electrode-supported cells. The cell material sets are optimized for the electrolysis mode ofmore » operation. Details of the cells and stacks will be provided along with details of the test apparatus, procedures, and results.« less

High-performance workplace practices in nursing homes: an economic perspective.

PubMed

Bishop, Christine E

2014-02-01

To develop implications for research, practice and policy, selected economics and human resources management research literature was reviewed to compare and contrast nursing home culture change work practices with high-performance human resource management systems in other industries. The organization of nursing home work under culture change has much in common with high-performance work systems, which are characterized by increased autonomy for front-line workers, self-managed teams, flattened supervisory hierarchy, and the aspiration that workers use specific knowledge gained on the job to enhance quality and customization. However, successful high-performance work systems also entail intensive recruitment, screening, and on-going training of workers, and compensation that supports selective hiring and worker commitment; these features are not usual in the nursing home sector. Thus despite many parallels with high-performance work systems, culture change work systems are missing essential elements: those that require higher compensation. If purchasers, including public payers, were willing to pay for customized, resident-centered care, productivity gains could be shared with workers, and the nursing home sector could move from a low-road to a high-road employment system.

Mediaprocessors in medical imaging for high performance and flexibility

NASA Astrophysics Data System (ADS)

Managuli, Ravi; Kim, Yongmin

2002-05-01

New high performance programmable processors, called mediaprocessors, have been emerging since the early 1990s for various digital media applications, such as digital TV, set-top boxes, desktop video conferencing, and digital camcorders. Modern mediaprocessors, e.g., TI's TMS320C64x and Hitachi/Equator Technologies MAP-CA, can offer high performance utilizing both instruction-level and data-level parallelism. During this decade, with continued performance improvement and cost reduction, we believe that the mediaprocessors will become a preferred choice in designing imaging and video systems due to their flexibility in incorporating new algorithms and applications via programming and faster-time-to-market. In this paper, we will evaluate the suitability of these mediaprocessors in medical imaging. We will review the core routines of several medical imaging modalities, such as ultrasound and DR, and present how these routines can be mapped to mediaprocessors and their resultant performance. We will analyze the architecture of several leading mediaprocessors. By carefully mapping key imaging routines, such as 2D convolution, unsharp masking, and 2D FFT, to the mediaprocessor, we have been able to achieve comparable (if not better) performance to that of traditional hardwired approaches. Thus, we believe that future medical imaging systems will benefit greatly from these advanced mediaprocessors, offering significantly increased flexibility and adaptability, reducing the time-to-market, and improving the cost/performance ratio compared to the existing systems while meeting the high computing requirements.

Coated Porous Si for High Performance On-Chip Supercapacitors

NASA Astrophysics Data System (ADS)

Grigoras, K.; Keskinen, J.; Grönberg, L.; Ahopelto, J.; Prunnila, M.

2014-11-01

High performance porous Si based supercapacitor electrodes are demonstrated. High power density and stability is provided by ultra-thin TiN coating of the porous Si matrix. The TiN layer is deposited by atomic layer deposition (ALD), which provides sufficient conformality to reach the bottom of the high aspect ratio pores. Our porous Si supercapacitor devices exhibit almost ideal double layer capacitor characteristic with electrode volumetric capacitance of 7.3 F/cm3. Several orders of magnitude increase in power and energy density is obtained comparing to uncoated porous silicon electrodes. Good stability of devices is confirmed performing several thousands of charge/discharge cycles.

High-performance fiber-reinforced concrete in a bridge deck.

DOT National Transportation Integrated Search

2005-01-01

The purpose of this research was to compare the performance of high-performance fiber-reinforced concrete (FRC) with that of conventional concrete in a bridge deck. FRC is expected to increase toughness, provide enhanced residual strength, and minimi...

Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac.

PubMed

Wu, Q; Ma, H Y; Yang, Y; Sun, L T; Zhang, X Z; Zhang, Z M; Zhao, H Y; He, Y; Zhao, H W

2016-02-01

Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

NASA Astrophysics Data System (ADS)

Wu, Q.; Ma, H. Y.; Yang, Y.; Sun, L. T.; Zhang, X. Z.; Zhang, Z. M.; Zhao, H. Y.; He, Y.; Zhao, H. W.

2016-02-01

Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Q., E-mail: wuq@impcas.ac.cn; Ma, H. Y.; Yang, Y.

Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimummore » width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.« less

Enhancements to High Temperature In-Pile Thermocouple Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

J.C. Crepeau; J.L. Rempe; J.E. Daw

2008-03-31

A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped molybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of themore » art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing

Enhancements to High Temperature In-Pile Thermocouple Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. C. Crepeau; J. L. Rempe; J. E. Daw

2008-03-01

A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped lybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of themore » art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 °C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing

Superwettability-Induced Confined Reaction toward High-Performance Flexible Electrodes.

PubMed

Xiong, Weiwei; Liu, Hongliang; Zhou, Yahong; Ding, Yi; Zhang, Xiqi; Jiang, Lei

2016-05-18

To find a general strategy to realize confinement of the conductive layer for high-performance flexible electrodes, with improved interfacial adhesion and high conductivity, is of important scientific significance. In this work, superwettability-induced confined reaction is used to fabricate high-performance flexible Ag/polymer electrodes, showing significantly improved silver conversion efficiency and interfacial adhesion. The as-prepared flexible electrodes by superhydrophilic polymeric surface under oil are highly conductive with an order of magnitude higher than the Ag/polymer electrodes obtained from original polymeric surface. The high conductivity achieved via superhydrophilic confinement is ascribed to the fact that the superhydrophilic polymeric surface can enhance the reaction rate of silver deposition and reduce the size of silver nanoparticles to achieve the densest packing. This new approach will provide a simple method to fabricate flexible and highly conductive Ag/polymer electrodes with excellent adhesion between the conductive layer and the substrate, and can be extended to other metal/polymeric electrodes or alloy/polymeric electrodes.

Clinical outcomes of the high-performance membrane dialyzer.

PubMed

Koda, Yutaka

2011-01-01

HPM (high-performance membrane or high-flux membrane) has better biocompatibility and higher capacity to remove retention solutes of large molecular weight, which has been proven to be toxic especially to cardiovascular and skeletal organs. To date, several non-randomized observational studies have shown a reduction in morbidity and mortality in HPM-treated patients compared with low-flux conventional membrane. Meanwhile, two randomized controlled trials were unable to reveal the superiority of high-flux membrane in survival of all-cause mortality, but suggested a significant benefit by subgroup analyses or post-hoc analyses in patients with diabetes, hypoalbuminemia and long duration of prior dialysis. Thus, the results of the published studies are conflicting and it still cannot be explained whether the effect is based on the biocompatibility of the membrane or on the differences in the clearance of middle molecules, or on the microbiological purity of dialysate which improved simultaneously with the flux increment. As survival outcome might be determined by additional multiple confounding factors, dialysis-related or non-dialysis-related, investigations to control them are difficult to perform. Although the clinical results are non-conclusive and it is still unanswered how much large molecule removal is required to improve outcomes in routine clinical practice, there is a considerable amount of biological plausibility for high-flux dialysis or middle molecule removal. Further trials will be required to confirm what patient group benefits the most, the magnitude of advantages and how large the molecules are and how much molecule removal is acceptable using advanced high-performance dialyzers. Dispersing hazardous effects by a low-quality therapy should be taken more seriously than practicing a high-quality therapy of uncertain superiority. Copyright © 2011 S. Karger AG, Basel.

Multi-Grid detector for neutron spectroscopy: results obtained on time-of-flight spectrometer CNCS

NASA Astrophysics Data System (ADS)

Anastasopoulos, M.; Bebb, R.; Berry, K.; Birch, J.; Bryś, T.; Buffet, J.-C.; Clergeau, J.-F.; Deen, P. P.; Ehlers, G.; van Esch, P.; Everett, S. M.; Guerard, B.; Hall-Wilton, R.; Herwig, K.; Hultman, L.; Höglund, C.; Iruretagoiena, I.; Issa, F.; Jensen, J.; Khaplanov, A.; Kirstein, O.; Lopez Higuera, I.; Piscitelli, F.; Robinson, L.; Schmidt, S.; Stefanescu, I.

2017-04-01

The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.

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.

High performance optical materials cyclo olefin polymer ZEONEX

NASA Astrophysics Data System (ADS)

Obuchi, Kazuyuki; Komatsu, Masaaki; Minami, Koji

2007-09-01

ZEON CORPORATION developed innovative optical plastic Cyclo Olefin Polymer (COP), ZEONEX (R) with own technology in 1990 then started commercial production of ZEONEX (R) for optical applications with its very unique properties such as high light transmission, low birefringence, low water absorption, and high glass-transition temperature etc. ZEONEX (R) exhibits outstanding optical performance even under high humidity and temperature conditions. In order to meet increasing requirements of optical market, ZEON CORPORATION newly developed ZEONEX (R)F52R which has high glass-transition temperature 156 deg. C and shows the feature of very low focal length change after high-temperature and high-humidity test.

"Live High-Train Low and High" Hypoxic Training Improves Team-Sport Performance.

PubMed

Brocherie, Franck; Millet, Grégoire P; Hauser, Anna; Steiner, Thomas; Rysman, Julien; Wehrlin, Jon P; Girard, Olivier

2015-10-01

This study aims to investigate physical performance and hematological changes in 32 elite male team-sport players after 14 d of "live high-train low" (LHTL) training in normobaric hypoxia (≥14 h·d at 2800-3000 m) combined with repeated-sprint training (six sessions of four sets of 5 × 5-s sprints with 25 s of passive recovery) either in normobaric hypoxia at 3000 m (LHTL + RSH, namely, LHTLH; n = 11) or in normoxia (LHTL + RSN, namely, LHTL; n = 12) compared with controlled "live low-train low" (LLTL; n = 9) training. Before (Pre), immediately after (Post-1), and 3 wk after (Post-2) the intervention, hemoglobin mass (Hbmass) was measured in duplicate [optimized carbon monoxide (CO) rebreathing method], and vertical jump, repeated-sprint (8 × 20 m-20 s recovery), and Yo-Yo Intermittent Recovery level 2 (YYIR2) performances were tested. Both hypoxic groups similarly increased their Hbmass at Post-1 and Post-2 in reference to Pre (LHTLH: +4.0%, P < 0.001 and +2.7%, P < 0.01; LHTL: +3.0% and +3.0%, both P < 0.001), whereas no change occurred in LLTL. Compared with Pre, YYIR2 performance increased by ∼21% at Post-1 (P < 0.01) and by ∼45% at Post-2 (P < 0.001), with no difference between the two intervention groups (vs no change in LLTL). From Pre to Post-1, cumulated sprint time decreased in LHTLH (-3.6%, P < 0.001) and LHTL (-1.9%, P < 0.01), but not in LLTL (-0.7%), and remained significantly reduced at Post-2 (-3.5%, P < 0.001) in LHTLH only. Vertical jump performance did not change. "Live high-train low and high" hypoxic training interspersed with repeated sprints in hypoxia for 14 d (in season) increases the Hbmass, YYIR2 performance, and repeated-sprint ability of elite field team-sport players, with benefits lasting for at least 3 wk postintervention.

NAVIGATION PERFORMANCE IN HIGH EARTH ORBITS USING NAVIGATOR GPS RECEIVER

NASA Technical Reports Server (NTRS)

Bamford, William; Naasz, Bo; Moreau, Michael C.

2006-01-01

NASA GSFC has developed a GPS receiver that can acquire and track GPS signals with sensitivity significantly lower than conventional GPS receivers. This opens up the possibility of using GPS based navigation for missions in high altitude orbit, such as Geostationary Operational Environmental Satellites (GOES) in a geostationary orbit, and the Magnetospheric MultiScale (MMS) Mission, in highly eccentric orbits extending to 12 Earth radii and higher. Indeed much research has been performed to study the feasibility of using GPS navigation in high Earth orbits and the performance achievable. Recently, GSFC has conducted a series of hardware in-the-loop tests to assess the performance of this new GPS receiver in various high Earth orbits of interest. Tracking GPS signals to down to approximately 22-25 dB-Hz, including signals from the GPS transmitter side-lobes, steady-state navigation performance in a geostationary orbit is on the order of 10 meters. This paper presents the results of these tests, as well as sensitivity analysis to such factors as ionosphere masks, use of GPS side-lobe signals, and GPS receiver sensitivity.

Rotordynamic Instability Problems in High-Performance Turbomachinery, 1986

NASA Technical Reports Server (NTRS)

1987-01-01

The first rotordynamics workshop proceedings (NASA CP-2133, 1980) emphasized a feeling of uncertainty in predicting the stability of characteristics of high-performance turbomachinery. In the second workshop proceedings (NASA CP-2250, 1982) these uncertainities were reduced through programs established to systematically resolve problems, with emphasis on experimental validiation of the forces that influence rotordynamics. In third proceedings (NASA CP-2338, 1984) many programs for predicting or measuring forces and force coefficients in high-performance turbomachinery produced results. Data became available for designing new machines with enhanced stability characteristics or for upgrading existing machines. The present workshop proceedings illustrates a continued trend toward a more unified view of rotordynamic instability problems and several encouraging new analytical developments.

Highly conductive porous Na-embedded carbon nanowalls for high-performance capacitive deionization

NASA Astrophysics Data System (ADS)

Chang, Liang; Hu, Yun Hang

2018-05-01

Highly conductive porous Na-embedded carbon nanowalls (Na@C), which were recently invented, have exhibited excellent performance for dye-sensitized solar cells and electric double-layer capacitors. In this work, Na@C was demonstrated as an excellent electrode material for capacitive deionization (CDI). In a three-electrode configuration system, the specific capacity of the Na@C electrodes can achieve 306.4 F/g at current density of 0.2 A/g in 1 M NaCl, which is higher than that (235.2 F/g) of activated carbon (AC) electrodes. Furthermore, a high electrosorption capacity of 8.75 mg g-1 in 100 mg/L NaCl was obtained with the Na@C electrodes in a batch-mode capacitive deionization cell. It exceeds the electrosorption capacity (4.08 mg g-1) of AC electrodes. The Na@C electrode also showed a promising cycle stability. The excellent performance of Na@C electrode for capacitive deionization (CDI) can be attributed to its high electrical conductivity and large accessible surface area.

High Performance Flat Plate Solar Thermal Collector Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rockenbaugh, Caleb; Dean, Jesse; Lovullo, David

2016-09-01

This report was prepared for the General Services Administration by the National Renewable Energy Laboratory. The Honeycomb Solar Thermal Collector (HSTC) is a flat plate solar thermal collector that shows promising high efficiencies over a wide range of climate zones. The technical objectives of this study are to: 1) verify collector performance, 2) compare that performance to other market-available collectors, 3) verify overheat protection, and 4) analyze the economic performance of the HSTC both at the demonstration sites and across a matrix of climate zones and utility markets.

High-performance silicon photonics technology for telecommunications applications.

PubMed

Yamada, Koji; Tsuchizawa, Tai; Nishi, Hidetaka; Kou, Rai; Hiraki, Tatsurou; Takeda, Kotaro; Fukuda, Hiroshi; Ishikawa, Yasuhiko; Wada, Kazumi; Yamamoto, Tsuyoshi

2014-04-01

By way of a brief review of Si photonics technology, we show that significant improvements in device performance are necessary for practical telecommunications applications. In order to improve device performance in Si photonics, we have developed a Si-Ge-silica monolithic integration platform, on which compact Si-Ge-based modulators/detectors and silica-based high-performance wavelength filters are monolithically integrated. The platform features low-temperature silica film deposition, which cannot damage Si-Ge-based active devices. Using this platform, we have developed various integrated photonic devices for broadband telecommunications applications.

High-performance silicon photonics technology for telecommunications applications

PubMed Central

Yamada, Koji; Tsuchizawa, Tai; Nishi, Hidetaka; Kou, Rai; Hiraki, Tatsurou; Takeda, Kotaro; Fukuda, Hiroshi; Ishikawa, Yasuhiko; Wada, Kazumi; Yamamoto, Tsuyoshi

2014-01-01

By way of a brief review of Si photonics technology, we show that significant improvements in device performance are necessary for practical telecommunications applications. In order to improve device performance in Si photonics, we have developed a Si-Ge-silica monolithic integration platform, on which compact Si-Ge–based modulators/detectors and silica-based high-performance wavelength filters are monolithically integrated. The platform features low-temperature silica film deposition, which cannot damage Si-Ge–based active devices. Using this platform, we have developed various integrated photonic devices for broadband telecommunications applications. PMID:27877659

High-performance silicon photonics technology for telecommunications applications

NASA Astrophysics Data System (ADS)

Yamada, Koji; Tsuchizawa, Tai; Nishi, Hidetaka; Kou, Rai; Hiraki, Tatsurou; Takeda, Kotaro; Fukuda, Hiroshi; Ishikawa, Yasuhiko; Wada, Kazumi; Yamamoto, Tsuyoshi

2014-04-01

By way of a brief review of Si photonics technology, we show that significant improvements in device performance are necessary for practical telecommunications applications. In order to improve device performance in Si photonics, we have developed a Si-Ge-silica monolithic integration platform, on which compact Si-Ge-based modulators/detectors and silica-based high-performance wavelength filters are monolithically integrated. The platform features low-temperature silica film deposition, which cannot damage Si-Ge-based active devices. Using this platform, we have developed various integrated photonic devices for broadband telecommunications applications.

Ion-Transport Design for High-Performance Na+-Based Electrochromics.

PubMed

Li, Ran; Li, Kerui; Wang, Gang; Li, Lei; Zhang, Qiangqiang; Yan, Jinhui; Chen, Yao; Zhang, Qinghong; Hou, Chengyi; Li, Yaogang; Wang, Hongzhi

2018-04-24

Sodium ion (Na + )-based electrochemical systems have been extensively investigated in batteries and supercapacitors and also can be quality candidates for electrochromic (EC) devices. However, poor diffusion kinetics and severe EC performance degradation occur during the intercalation/deintercalation processes because the ionic radii of Na + are larger than those of conventional intercalation ions. Here, through intentional design of ion-transport channels in metal-organic frameworks (MOFs), Na + serves as an efficient intercalation ion for incorporation into a nanostructured electrode with a high diffusion coefficient of approximately 10 -8 cm 2 s -1 . As a result, the well-designed MOF-based EC device demonstrates desirable Na + EC performance, including fast switching speed, multicolor switching, and high stability. A smart "quick response code" display is fabricated using a mask-free laser writing method for application in the "Internet of Things". In addition, the concept of ion transport pathway design can be widely adopted for fabricating high-performance ion intercalation materials and devices for consumer electronics.

Multichannel Detection in High-Performance Liquid Chromatography.

ERIC Educational Resources Information Center

Miller, James C.; And Others

1982-01-01

A linear photodiode array is used as the photodetector element in a new ultraviolet-visible detection system for high-performance liquid chromatography (HPLC). Using a computer network, the system processes eight different chromatographic signals simultaneously in real-time and acquires spectra manually/automatically. Applications in fast HPLC…

Expanding the Scope of High-Performance Computing Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uram, Thomas D.; Papka, Michael E.

The high-performance computing centers of the future will expand their roles as service providers, and as the machines scale up, so should the sizes of the communities they serve. National facilities must cultivate their users as much as they focus on operating machines reliably. The authors present five interrelated topic areas that are essential to expanding the value provided to those performing computational science.

Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?

PubMed

Chang, Chen-Kang; Borer, Katarina; Lin, Po-Ju

2017-02-01

Low-carbohydrate-high-fat (LCHF) diets have been used as a means of weight loss and control of symptoms in several clinical conditions. There is emerging evidence that the metabolic changes induced by LCHF diets enhance endurance performance. The aims of this review are to examine the evidence of LCHF diets in improving various aspects of athletic performance. Long-term LCHF dietary intake may help control body weight and fat mass while maintaining lean body mass in athletes in weight-sensitive sports. LCHF-adapted endurance athletes can reach the maximal fat oxidation rate of approximately 1.5 g/min, with a lower carbohydrate oxidation rate and similar muscle glycogen content and a resynthesis rate compared to their counterparts consuming high-carbohydrate-low-fat (HCLF) diets. The elevated fat oxidation rate and glycogen sparing effect may improve performance in ultra-endurance events. These metabolic changes may also prevent the decline in performance in later stages of repeated high-intensity movements, in which the aerobic metabolism becomes more important. However, elevated blood concentrations of non-esterified fatty acids and ammonia during exercise after LCHF diets may lead to early development of central fatigue. It appears that at least several months of adaptation to a LCHF diet are required for the metabolic changes and restoration of muscle glycogen to occur. Further investigations on LCHF diets are needed regarding (1) performance after weight loss in weight-categorized sports; (2) repeated high-intensity exercise performance; (3) development of central fatigue during endurance events; (4) perceptual-motor performance during prolonged intermittent sports; and (5) ideal dietary fatty acid compositions.

High-efficiency high performance liquid chromatographic analysis of red wine anthocyanins.

PubMed

de Villiers, André; Cabooter, Deirdre; Lynen, Frédéric; Desmet, Gert; Sandra, Pat

2011-07-22

The analysis of anthocyanins in natural products is of significant relevance in recent times due to the recognised health benefits associated with their consumption. In red grapes and wines in particular, anthocyanins are known to contribute important properties to the sensory (colour and taste), anti-oxidant- and ageing characteristics. However, the detailed investigation of the alteration of these compounds during wine ageing is hampered by the challenges associated with the separation of grape-derived anthocyanins and their derived products. High performance liquid chromatography (HPLC) is primarily used for this purpose, often in combination with mass spectrometric (MS) detection, although conventional HPLC methods provide incomplete resolution. We have previously demonstrated how on-column inter-conversion reactions are responsible for poor chromatographic efficiency in the HPLC analysis of anthocyanins, and how an increase in temperature and decrease in particle size may improve the chromatographic performance. In the current contribution an experimental configuration for the high efficiency analysis of anthocyanins is derived using the kinetic plot method (KPM). Further, it is shown how analysis under optimal conditions, in combination with MS detection, delivers much improved separation and identification of red wine anthocyanins and their derived products. This improved analytical performance holds promise for the in-depth investigation of these influential compounds in wine during ageing. Copyright © 2011 Elsevier B.V. All rights reserved.

Dynamic Open Inquiry Performances of High-School Biology Students

ERIC Educational Resources Information Center

Zion, Michal; Sadeh, Irit

2010-01-01

In examining open inquiry projects among high-school biology students, we found dynamic inquiry performances expressed in two criteria: "changes occurring during inquiry" and "procedural understanding". Characterizing performances in a dynamic open inquiry project can shed light on both the procedural and epistemological…

Inorganic nanostructured materials for high performance electrochemical supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Sheng; Sun, Shouheng; You, Xiao-Zeng

2014-01-01

Electrochemical supercapacitors (ES) are a well-known energy storage system that has high power density, long life-cycle and fast charge-discharge kinetics. Nanostructured materials are a new generation of electrode materials with large surface area and short transport/diffusion path for ions and electrons to achieve high specific capacitance in ES. This mini review highlights recent developments of inorganic nanostructure materials, including carbon nanomaterials, metal oxide nanoparticles, and metal oxide nanowires/nanotubes, for high performance ES applications.

Inorganic nanostructured materials for high performance electrochemical supercapacitors.

PubMed

Liu, Sheng; Sun, Shouheng; You, Xiao-Zeng

2014-02-21

Electrochemical supercapacitors (ES) are a well-known energy storage system that has high power density, long life-cycle and fast charge-discharge kinetics. Nanostructured materials are a new generation of electrode materials with large surface area and short transport/diffusion path for ions and electrons to achieve high specific capacitance in ES. This mini review highlights recent developments of inorganic nanostructure materials, including carbon nanomaterials, metal oxide nanoparticles, and metal oxide nanowires/nanotubes, for high performance ES applications.

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

Critical Role of Monoclinic Polarization Rotation in High-Performance Perovskite Piezoelectric Materials.

PubMed

Liu, Hui; Chen, Jun; Fan, Longlong; Ren, Yang; Pan, Zhao; Lalitha, K V; Rödel, Jürgen; Xing, Xianran

2017-07-07

High-performance piezoelectric materials constantly attract interest for both technological applications and fundamental research. The understanding of the origin of the high-performance piezoelectric property remains a challenge mainly due to the lack of direct experimental evidence. We perform in situ high-energy x-ray diffraction combined with 2D geometry scattering technology to reveal the underlying mechanism for the perovskite-type lead-based high-performance piezoelectric materials. The direct structural evidence reveals that the electric-field-driven continuous polarization rotation within the monoclinic plane plays a critical role to achieve the giant piezoelectric response. An intrinsic relationship between the crystal structure and piezoelectric performance in perovskite ferroelectrics has been established: A strong tendency of electric-field-driven polarization rotation generates peak piezoelectric performance and vice versa. Furthermore, the monoclinic M_{A} structure is the key feature to superior piezoelectric properties as compared to other structures such as monoclinic M_{B}, rhombohedral, and tetragonal. A high piezoelectric response originates from intrinsic lattice strain, but little from extrinsic domain switching. The present results will facilitate designing high-performance perovskite piezoelectric materials by enhancing the intrinsic lattice contribution with easy and continuous polarization rotation.

Aerodynamic and acoustic performance of high Mach number inlets

NASA Technical Reports Server (NTRS)

Lumsdaine, E.; Clark, L. R.; Cherng, J. C.; Tag, I.

1977-01-01

Experimental results were obtained for two types of high Mach number inlets, one with a translating centerbody and one with a fixed geometry (collapsing cowl) without centerbody. The aerodynamic and acoustic performance of these inlets was examined. The effects of several parameters such as area ratio and length-diameter ratio were investigated. The translating centerbody inlet was found to be superior to the collapsing cowl inlet both acoustically and aerodynamically, particularly for area ratios greater than 1.5. Comparison of length-diameter ratio and area ratio effects on performance near choked flow showed the latter parameter to be more significant. Also, greater high frequency noise attenuation was achieved by increasing Mach number from low to high subsonic values.

High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

2015-10-01

Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g-1 present high specific capacities of the 308 and 200 F g-1 in KOH electrolyte at current densities of 0.1 and 10 A g-1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g-1 at 0.1 A g-1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry.

High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors.

PubMed

Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

2015-10-16

Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m(2) g(-1) present high specific capacities of the 308 and 200 F g(-1) in KOH electrolyte at current densities of 0.1 and 10 A g(-1), respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g(-1) at 0.1 A g(-1) and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry.

High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

PubMed Central

Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

2015-01-01

Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g−1 present high specific capacities of the 308 and 200 F g−1 in KOH electrolyte at current densities of 0.1 and 10 A g−1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g−1 at 0.1 A g−1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry. PMID:26472144

High Temperature Carbonized Grass as a High Performance Sodium Ion Battery Anode.

PubMed

Zhang, Fang; Yao, Yonggang; Wan, Jiayu; Henderson, Doug; Zhang, Xiaogang; Hu, Liangbing

2017-01-11

Hard carbon is currently considered the most promising anode candidate for room temperature sodium ion batteries because of its relatively high capacity, low cost, and good scalability. In this work, switchgrass as a biomass example was carbonized under an ultrahigh temperature, 2050 °C, induced by Joule heating to create hard carbon anodes for sodium ion batteries. Switchgrass derived carbon materials intrinsically inherit its three-dimensional porous hierarchical architecture, with an average interlayer spacing of 0.376 nm. The larger interlayer spacing than that of graphite allows for the significant Na ion storage performance. Compared to the sample carbonized under 1000 °C, switchgrass derived carbon at 2050 °C induced an improved initial Coulombic efficiency. Additionally, excellent rate capability and superior cycling performance are demonstrated for the switchgrass derived carbon due to the unique high temperature treatment.

SISYPHUS: A high performance seismic inversion factory

NASA Astrophysics Data System (ADS)

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

2016-04-01

In the recent years the massively parallel high performance computers became the standard instruments for solving the forward and inverse problems in seismology. The respective software packages dedicated to forward and inverse waveform modelling specially designed for such computers (SPECFEM3D, SES3D) became mature and widely available. These packages achieve significant computational performance and provide researchers with an opportunity to solve problems of bigger size at higher resolution within a shorter time. However, a typical seismic inversion process contains various activities that are beyond the common solver functionality. They include management of information on seismic events and stations, 3D models, observed and synthetic seismograms, pre-processing of the observed signals, computation of misfits and adjoint sources, minimization of misfits, and process workflow management. These activities are time consuming, seldom sufficiently automated, and therefore represent a bottleneck that can substantially offset performance benefits provided by even the most powerful modern supercomputers. Furthermore, a typical system architecture of modern supercomputing platforms is oriented towards the maximum computational performance and provides limited standard facilities for automation of the supporting activities. We present a prototype solution that automates all aspects of the seismic inversion process and is tuned for the modern massively parallel high performance computing systems. We address several major aspects of the solution architecture, which include (1) design of an inversion state database for tracing all relevant aspects of the entire solution process, (2) design of an extensible workflow management framework, (3) integration with wave propagation solvers, (4) integration with optimization packages, (5) computation of misfits and adjoint sources, and (6) process monitoring. The inversion state database represents a hierarchical structure with

System Resource Allocations | High-Performance Computing | NREL

Science.gov Websites

Allocations System Resource Allocations To use NREL's high-performance computing (HPC) resources : Compute hours on NREL HPC Systems including Peregrine and Eagle Storage space (in Terabytes) on Peregrine , Eagle and Gyrfalcon. Allocations are principally done in response to an annual call for allocation

Achieving High Performance with FPGA-Based Computing

PubMed Central

Herbordt, Martin C.; VanCourt, Tom; Gu, Yongfeng; Sukhwani, Bharat; Conti, Al; Model, Josh; DiSabello, Doug

2011-01-01

Numerous application areas, including bioinformatics and computational biology, demand increasing amounts of processing capability. In many cases, the computation cores and data types are suited to field-programmable gate arrays. The challenge is identifying the design techniques that can extract high performance potential from the FPGA fabric. PMID:21603088

Complex performance during exposure to high temperatures.

DOT National Transportation Integrated Search

1969-06-01

The effects of high temperature on psychomotor performance and physiological function were studied on male pilots (age 30-51) holding a current medical certificate. A total of 41 runs were made at neutral (23.8C (75F), or hot (60.0C (140F), 71.1C (16...

Insights into early lithic technologies from ethnography.

PubMed

Hayden, Brian

2015-11-19

Oldowan lithic assemblages are often portrayed as a product of the need to obtain sharp flakes for cutting into animal carcases. However, ethnographic and experimental research indicates that the optimal way to produce flakes for such butchering purposes is via bipolar reduction of small cryptocrystalline pebbles rather than from larger crystalline cores resembling choppers. Ethnographic observations of stone tool-using hunter-gatherers in environments comparable with early hominins indicate that most stone tools (particularly chopper forms and flake tools) were used for making simple shaft tools including spears, digging sticks and throwing sticks. These tools bear strong resemblances to Oldowan stone tools. Bipolar reduction for butchering probably preceded chopper-like core reduction and provides a key link between primate nut-cracking technologies and the emergence of more sophisticated lithic technologies leading to the Oldowan. © 2015 The Author(s).

Insights into early lithic technologies from ethnography

PubMed Central

Hayden, Brian

2015-01-01

Oldowan lithic assemblages are often portrayed as a product of the need to obtain sharp flakes for cutting into animal carcases. However, ethnographic and experimental research indicates that the optimal way to produce flakes for such butchering purposes is via bipolar reduction of small cryptocrystalline pebbles rather than from larger crystalline cores resembling choppers. Ethnographic observations of stone tool-using hunter-gatherers in environments comparable with early hominins indicate that most stone tools (particularly chopper forms and flake tools) were used for making simple shaft tools including spears, digging sticks and throwing sticks. These tools bear strong resemblances to Oldowan stone tools. Bipolar reduction for butchering probably preceded chopper-like core reduction and provides a key link between primate nut-cracking technologies and the emergence of more sophisticated lithic technologies leading to the Oldowan. PMID:26483534

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.

High Performance Computing Operations Review Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cupps, Kimberly C.

2013-12-19

The High Performance Computing Operations Review (HPCOR) meeting—requested by the ASC and ASCR program headquarters at DOE—was held November 5 and 6, 2013, at the Marriott Hotel in San Francisco, CA. The purpose of the review was to discuss the processes and practices for HPC integration and its related software and facilities. Experiences and lessons learned from the most recent systems deployed were covered in order to benefit the deployment of new systems.

High-performance superconductors for Fusion Nuclear Science Facility

DOE PAGES

Zhai, Yuhu; Kessel, Chuck; Barth, Christian; ...

2016-11-09

High-performance superconducting magnets play an important role in the design of the next step large-scale, high-field fusion reactors such as the fusion nuclear science facility (FNSF) and the spherical tokamak (ST) pilot plant beyond ITER. Here, Princeton Plasma Physics Laboratory is currently leading the design studies of the FNSF and the ST pilot plant study. ITER, which is under construction in the south of France, utilizes the state-of-the-art low temperature superconducting magnet technology based on the cable-in-conduit conductor design, where over a thousand multifilament Nb 3Sn superconducting strands are twisted together to form a high-current-carrying cable inserted into a steelmore » jacket for coil windings. We present design options of the high-performance superconductors in the winding pack for the FNSF toroidal field magnet system based on the toroidal field radial build from the system code. For the low temperature superconductor options, the advanced J cNb 3Sn RRP strands (J c > 1000 A/mm 2 at 16 T, 4 K) from Oxford Superconducting Technology are under consideration. For the high-temperature superconductor options, the rectangular-shaped high-current HTS cable made of stacked YBCO tapes will be considered to validate feasibility of TF coil winding pack design for the ST-FNSF magnets.« less

High-performance superconductors for Fusion Nuclear Science Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhai, Yuhu; Kessel, Chuck; Barth, Christian

High-performance superconducting magnets play an important role in the design of the next step large-scale, high-field fusion reactors such as the fusion nuclear science facility (FNSF) and the spherical tokamak (ST) pilot plant beyond ITER. Here, Princeton Plasma Physics Laboratory is currently leading the design studies of the FNSF and the ST pilot plant study. ITER, which is under construction in the south of France, utilizes the state-of-the-art low temperature superconducting magnet technology based on the cable-in-conduit conductor design, where over a thousand multifilament Nb 3Sn superconducting strands are twisted together to form a high-current-carrying cable inserted into a steelmore » jacket for coil windings. We present design options of the high-performance superconductors in the winding pack for the FNSF toroidal field magnet system based on the toroidal field radial build from the system code. For the low temperature superconductor options, the advanced J cNb 3Sn RRP strands (J c > 1000 A/mm 2 at 16 T, 4 K) from Oxford Superconducting Technology are under consideration. For the high-temperature superconductor options, the rectangular-shaped high-current HTS cable made of stacked YBCO tapes will be considered to validate feasibility of TF coil winding pack design for the ST-FNSF magnets.« less

Manufacturing Advantage: Why High-Performance Work Systems Pay Off.

ERIC Educational Resources Information Center

Appelbaum, Eileen; Bailey, Thomas; Berg, Peter; Kalleberg, Arne L.

A study examined the relationship between high-performance workplace practices and the performance of plants in the following manufacturing industries: steel, apparel, and medical electronic instruments and imaging. The multilevel research methodology combined the following data collection activities: (1) site visits; (2) collection of plant…

Friction Stir Additive Manufacturing: Route to High Structural Performance

NASA Astrophysics Data System (ADS)

Palanivel, S.; Sidhar, H.; Mishra, R. S.

2015-03-01

Aerospace and automotive industries provide the next big opportunities for additive manufacturing. Currently, the additive industry is confronted with four major challenges that have been identified in this article. These challenges need to be addressed for the additive technologies to march into new frontiers and create additional markets. Specific potential success in the transportation sectors is dependent on the ability to manufacture complicated structures with high performance. Most of the techniques used for metal-based additive manufacturing are fusion based because of their ability to fulfill the computer-aided design to component vision. Although these techniques aid in fabrication of complex shapes, achieving high structural performance is a key problem due to the liquid-solid phase transformation. In this article, friction stir additive manufacturing (FSAM) is shown as a potential solid-state process for attaining high-performance lightweight alloys for simpler geometrical applications. To illustrate FSAM as a high-performance route, manufactured builds of Mg-4Y-3Nd and AA5083 are shown as examples. In the Mg-based alloy, an average hardness of 120 HV was achieved in the built structure and was significantly higher than that of the base material (97 HV). Similarly for the Al-based alloy, compared with the base hardness of 88 HV, the average built hardness was 104 HV. A potential application of FSAM is illustrated by taking an example of a simple stiffener assembly.

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.

Coal-fired high performance power generating system. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

As a result of the investigations carried out during Phase 1 of the Engineering Development of Coal-Fired High-Performance Power Generation Systems (Combustion 2000), the UTRC-led Combustion 2000 Team is recommending the development of an advanced high performance power generation system (HIPPS) whose high efficiency and minimal pollutant emissions will enable the US to use its abundant coal resources to satisfy current and future demand for electric power. The high efficiency of the power plant, which is the key to minimizing the environmental impact of coal, can only be achieved using a modern gas turbine system. Minimization of emissions can bemore » achieved by combustor design, and advanced air pollution control devices. The commercial plant design described herein is a combined cycle using either a frame-type gas turbine or an intercooled aeroderivative with clean air as the working fluid. The air is heated by a coal-fired high temperature advanced furnace (HITAF). The best performance from the cycle is achieved by using a modern aeroderivative gas turbine, such as the intercooled FT4000. A simplified schematic is shown. In the UTRC HIPPS, the conversion efficiency for the heavy frame gas turbine version will be 47.4% (HHV) compared to the approximately 35% that is achieved in conventional coal-fired plants. This cycle is based on a gas turbine operating at turbine inlet temperatures approaching 2,500 F. Using an aeroderivative type gas turbine, efficiencies of over 49% could be realized in advanced cycle configuration (Humid Air Turbine, or HAT). Performance of these power plants is given in a table.« less

Renewable-juglone-based high-performance sodium-ion batteries.

PubMed

Wang, Hua; Hu, Pengfei; Yang, Jie; Gong, Guangming; Guo, Lin; Chen, Xiaodong

2015-04-08

A renewable-biomolecule-based electrode is developed through a facile synchronous reduction and self-assembly process, without any binder or additional conductive agent. The hybridized electrodes can be fabricated with arbitrary size and shape and exhibit superior capacity and cycle performance. The renewable-biomaterial-based high-performance electrodes will hold a place in future energy-storage devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Implementing High-Performance Geometric Multigrid Solver with Naturally Grained Messages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shan, Hongzhang; Williams, Samuel; Zheng, Yili

2015-10-26

Structured-grid linear solvers often require manually packing and unpacking of communication data to achieve high performance.Orchestrating this process efficiently is challenging, labor-intensive, and potentially error-prone.In this paper, we explore an alternative approach that communicates the data with naturally grained messagesizes without manual packing and unpacking. This approach is the distributed analogue of shared-memory programming, taking advantage of the global addressspace in PGAS languages to provide substantial programming ease. However, its performance may suffer from the large number of small messages. We investigate theruntime support required in the UPC ++ library for this naturally grained version to close the performance gapmore » between the two approaches and attain comparable performance at scale using the High-Performance Geometric Multgrid (HPGMG-FV) benchmark as a driver.« less

Development of a Flow Visualization Technique for Transient Fluid Flow

DTIC Science & Technology

1992-12-31

high repetition rates, 2 to 10 kHz. The CW laser with a chopper wheel is limited to 4 kHz with a relatively large pulse width of 125 microseconds. The... four data points are in one CRAY word *I I* print«" bufloop %d width %d bufbytes %d image offset %ld xoffset %d \

Parallel Reaction Monitoring: A Targeted Experiment Performed Using High Resolution and High Mass Accuracy Mass Spectrometry

PubMed Central

Rauniyar, Navin

2015-01-01

The parallel reaction monitoring (PRM) assay has emerged as an alternative method of targeted quantification. The PRM assay is performed in a high resolution and high mass accuracy mode on a mass spectrometer. This review presents the features that make PRM a highly specific and selective method for targeted quantification using quadrupole-Orbitrap hybrid instruments. In addition, this review discusses the label-based and label-free methods of quantification that can be performed with the targeted approach. PMID:26633379

Appropriate Use Policy | High-Performance Computing | NREL

Science.gov Websites

users of the National Renewable Energy Laboratory (NREL) High Performance Computing (HPC) resources government agency, National Laboratory, University, or private entity, the intellectual property terms (if issued a multifactor token which may be a physical token or a virtual token used with one-time password

High Performance Computing and Communications Panel Report.

ERIC Educational Resources Information Center

President's Council of Advisors on Science and Technology, Washington, DC.

This report offers advice on the strengths and weaknesses of the High Performance Computing and Communications (HPCC) initiative, one of five presidential initiatives launched in 1992 and coordinated by the Federal Coordinating Council for Science, Engineering, and Technology. The HPCC program has the following objectives: (1) to extend U.S.…

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…

Determination of Atomic and Molecular Excited-State Lifetimes Using an Opto-electronic Cross-Correlation Method.

DTIC Science & Technology

1981-10-07

new instrument (cf. Fig. 1) is simply a four - quadrant ring-diode multi- 5 plier (Fig. 2). The reference frequency (RF) and local oscillator (LO) inputs...movement, and scan speed of the corner-cube. Other Components. A rotating-sector chopper modulates the laser pulse train at a frequency of approximately 50...the cross-correlation experiment. In this application, the detection bandpass is simply displaced from DC to the chopper frequency; problems arising

An Experimental Evaluation of the Internal Flow Field of an Automotive Heating, Ventilating and Air Conditioning System

DTIC Science & Technology

1990-07-01

HVAC) was conducted. This study consisted of four primary experiments designed to provide a fairly complete description of the governing flow mechanisms...interest. In order to generate the 28 required optical characteristics, the laser beam was directed through a mechanical beam chopper and a series of...lenses. The beam chopper operated at a frequency of 75 chops per second to create series of laser pulses 1/75s in duration. Once chopped, the beam was

High performance, durable polymers including poly(phenylene)

DOEpatents

Fujimoto, Cy; Pratt, Harry; Anderson, Travis Mark

2017-02-28

The present invention relates to functionalized polymers including a poly(phenylene) structure. In some embodiments, the polymers and copolymers of the invention include a highly localized concentration of acidic moieties, which facilitate proton transport and conduction through networks formed from these polymers. In addition, the polymers can include functional moieties, such as electron-withdrawing moieties, to protect the polymeric backbone, thereby extending its durability. Such enhanced proton transport and durability can be beneficial for any high performance platform that employs proton exchange polymeric membranes, such as in fuel cells or flow batteries.

A Lithium-Air Battery Stably Working at High Temperature with High Rate Performance.

PubMed

Pan, Jian; Li, Houpu; Sun, Hao; Zhang, Ye; Wang, Lie; Liao, Meng; Sun, Xuemei; Peng, Huisheng

2018-02-01

Driven by the increasing requirements for energy supply in both modern life and the automobile industry, the lithium-air battery serves as a promising candidate due to its high energy density. However, organic solvents in electrolytes are likely to rapidly vaporize and form flammable gases under increasing temperatures. In this case, serious safety problems may occur and cause great harm to people. Therefore, a kind of lithium-air that can work stably under high temperature is desirable. Herein, through the use of an ionic liquid and aligned carbon nanotubes, and a fiber shaped design, a new type of lithium-air battery that can effectively work at high temperatures up to 140 °C is developed. Ionic liquids can offer wide electrochemical windows and low vapor pressures, as well as provide high thermal stability for lithium-air batteries. The aligned carbon nanotubes have good electric and heat conductivity. Meanwhile, the fiber format can offer both flexibility and weavability, and realize rapid heat conduction and uniform heat distribution of the battery. In addition, the high temperature has also largely improved the specific powers by increasing the ionic conductivity and catalytic activity of the cathode. Consequently, the lithium-air battery can work stably at 140 °C with a high specific current of 10 A g -1 for 380 cycles, indicating high stability and good rate performance at high temperatures. This work may provide an effective paradigm for the development of high-performance energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy efficient engine high-pressure turbine component rig performance test report

NASA Technical Reports Server (NTRS)

Leach, K. P.

1983-01-01

A rig test of the cooled high-pressure turbine component for the Energy Efficient Engine was successfully completed. The principal objective of this test was to substantiate the turbine design point performance as well as determine off-design performance with the interaction of the secondary flow system. The measured efficiency of the cooled turbine component was 88.5 percent, which surpassed the rig design goal of 86.5 percent. The secondary flow system in the turbine performed according to the design intent. Characterization studies showed that secondary flow system performance is insensitive to flow and pressure variations. Overall, this test has demonstrated that a highly-loaded, transonic, single-stage turbine can achieve a high level of operating efficiency.

High-Performance Buildings – Value, Messaging, Financial and Policy Mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, Molly

At the request of the Pacific Northwest National Laboratory, an in-depth analysis of the rapidly evolving state of real estate investments, high-performance building technology, and interest in efficiency was conducted by HaydenTanner, LLC, for the U.S. Department of Energy (DOE) Building Technologies Program. The analysis objectives were • to evaluate the link between high-performance buildings and their market value • to identify core messaging to motivate owners, investors, financiers, and others in the real estate sector to appropriately value and deploy high-performance strategies and technologies across new and existing buildings • to summarize financial mechanisms that facilitate increased investment inmore » these buildings. To meet these objectives, work consisted of a literature review of relevant writings, examination of existing and emergent financial and policy mechanisms, interviews with industry stakeholders, and an evaluation of the value implications through financial modeling. This report documents the analysis methodology and findings, conclusion and recommendations. Its intent is to support and inform the DOE Building Technologies Program on policy and program planning for the financing of high-performance new buildings and building retrofit projects.« less

Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?

PubMed Central

Borer, Katarina; Lin, Po-Ju

2017-01-01

Abstract Low-carbohydrate-high-fat (LCHF) diets have been used as a means of weight loss and control of symptoms in several clinical conditions. There is emerging evidence that the metabolic changes induced by LCHF diets enhance endurance performance. The aims of this review are to examine the evidence of LCHF diets in improving various aspects of athletic performance. Long-term LCHF dietary intake may help control body weight and fat mass while maintaining lean body mass in athletes in weight-sensitive sports. LCHF-adapted endurance athletes can reach the maximal fat oxidation rate of approximately 1.5 g/min, with a lower carbohydrate oxidation rate and similar muscle glycogen content and a resynthesis rate compared to their counterparts consuming high-carbohydrate-low-fat (HCLF) diets. The elevated fat oxidation rate and glycogen sparing effect may improve performance in ultra-endurance events. These metabolic changes may also prevent the decline in performance in later stages of repeated high-intensity movements, in which the aerobic metabolism becomes more important. However, elevated blood concentrations of non-esterified fatty acids and ammonia during exercise after LCHF diets may lead to early development of central fatigue. It appears that at least several months of adaptation to a LCHF diet are required for the metabolic changes and restoration of muscle glycogen to occur. Further investigations on LCHF diets are needed regarding (1) performance after weight loss in weight-categorized sports; (2) repeated high-intensity exercise performance; (3) development of central fatigue during endurance events; (4) perceptual-motor performance during prolonged intermittent sports; and (5) ideal dietary fatty acid compositions. PMID:28469746

Progress in a novel architecture for high performance processing

NASA Astrophysics Data System (ADS)

Zhang, Zhiwei; Liu, Meng; Liu, Zijun; Du, Xueliang; Xie, Shaolin; Ma, Hong; Ding, Guangxin; Ren, Weili; Zhou, Fabiao; Sun, Wenqin; Wang, Huijuan; Wang, Donglin

2018-04-01

The high performance processing (HPP) is an innovative architecture which targets on high performance computing with excellent power efficiency and computing performance. It is suitable for data intensive applications like supercomputing, machine learning and wireless communication. An example chip with four application-specific integrated circuit (ASIC) cores which is the first generation of HPP cores has been taped out successfully under Taiwan Semiconductor Manufacturing Company (TSMC) 40 nm low power process. The innovative architecture shows great energy efficiency over the traditional central processing unit (CPU) and general-purpose computing on graphics processing units (GPGPU). Compared with MaPU, HPP has made great improvement in architecture. The chip with 32 HPP cores is being developed under TSMC 16 nm field effect transistor (FFC) technology process and is planed to use commercially. The peak performance of this chip can reach 4.3 teraFLOPS (TFLOPS) and its power efficiency is up to 89.5 gigaFLOPS per watt (GFLOPS/W).

Longitudinal analysis of high-technology medical services and hospital financial performance.

PubMed

Zengul, Ferhat D; Weech-Maldonado, Robert; Ozaydin, Bunyamin; Patrician, Patricia A; OʼConnor, Stephen J

U.S. hospitals have been investing in high-technology medical services as a strategy to improve financial performance. Despite the interest in high-tech medical services, there is not much information available about the impact of high-tech services on financial performance. The aim of this study was to examine the impact of high-tech medical services on financial performance of U.S. hospitals by using the resource-based view of the firm as a conceptual framework. Fixed-effects regressions with 2 years lagged independent variables using a longitudinal panel sample of 3,268 hospitals (2005-2010). It was hypothesized that hospitals with rare or large numbers (breadth) of high-tech medical services will experience better financial performance. Fixed effects regression results supported the link between a larger breadth of high-tech services and total margin, but only among not-for-profit hospitals. Both breadth and rareness of high-tech services were associated with high total margin among not-for-profit hospitals. Neither breadth nor rareness of high-tech services was associated with operating margin. Although breadth and rareness of high-tech services resulted in lower expenses per inpatient day among not-for-profit hospitals, these lower costs were offset by lower revenues per inpatient day. Enhancing the breadth of high-tech services may be a legitimate organizational strategy to improve financial performance, especially among not-for-profit hospitals. Hospitals may experience increased productivity and efficiency, and therefore lower inpatient operating costs, as a result of newer technologies. However, the negative impact on operating revenue should caution hospital administrators about revenue reducing features of these technologies, which may be related to the payer mix that these technologies may attract. Therefore, managers should consider both the cost and revenue implications of these technologies.

Does Visual Performance Influence Head Impact Severity Among High School Football Athletes?

PubMed

Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W

2015-11-01

To compare the odds of sustaining moderate and severe head impacts, rather than mild, between high school football players with high and low visual performance. Prospective quasi-experimental. Clinical Research Center/On-field. Thirty-seven high school varsity football players. Athletes completed the Nike SPARQ Sensory Station visual assessment before the season. Head impact biomechanics were captured at all practices and games using the Head Impact Telemetry System. Each player was classified as either a high or low performer using a median split for each of the following visual performance measures: visual clarity, contrast sensitivity, depth perception, near-far quickness, target capture, perception span, eye-hand coordination, go/no go, and reaction time. We computed the odds of sustaining moderate and severe head impacts against the reference odds of sustaining mild head impacts across groups of high and low performers for each of the visual performance measures. Players with better near-far quickness had increased odds of sustaining moderate [odds ratios (ORs), 1.27; 95% confidence intervals (CIs), 1.04-1.56] and severe head impacts (OR, 1.45; 95% CI, 1.05-2.01) as measured by Head Impact Technology severity profile. High and low performers were at equal odds on all other measures. Better visual performance did not reduce the odds of sustaining higher magnitude head impacts. Visual performance may play less of a role than expected for protecting against higher magnitude head impacts among high school football players. Further research is needed to determine whether visual performance influences concussion risk. Based on our results, we do not recommend using visual training programs at the high school level for the purpose of reducing the odds of sustaining higher magnitude head impacts.

Performance Characterization of High Energy Commercial Lithium-ion Cells

NASA Technical Reports Server (NTRS)

Schneidegger, Brianne T.

2010-01-01

The NASA Glenn Research Center Electrochemistry Branch performed characterization of commercial lithium-ion cells to determine the cells' performance against Exploration Technology Development Program (ETDP) Key Performance Parameters (KPP). The goals of the ETDP Energy Storage Project require significant improvements in the specific energy of lithium-ion technology over the state-of-the-art. This work supports the high energy cell development for the Constellation customer Lunar Surface Systems (LSS). In support of these goals, testing was initiated in September 2009 with high energy cylindrical cells obtained from Panasonic and E-One Moli. Both manufacturers indicated the capability of their cells to deliver specific energy of at least 180 Wh/kg or higher. Testing is being performed at the NASA Glenn Research Center to evaluate the performance of these cells under temperature, rate, and cycling conditions relevant to the ETDP goals for high energy cells. The cell-level specific energy goal for high energy technology is 180 Wh/kg at a C/10 rate and 0 C. The threshold value is 165 Wh/kg. The goal is to operate for at least 2000 cycles at 100 percent DOD with greater than 80 percent capacity retention. The Panasonic NCR18650 cells were able to deliver nearly 200 Wh/kg at the aforementioned conditions. The E-One Moli ICR18650J cells also met the specific energy goal by delivering 183 Wh/kg. Though both cells met the goal for specific energy, this testing was only one portion of the testing required to determine the suitability of commercial cells for the ETDP. The cells must also meet goals for cycle life and safety. The results of this characterization are summarized in this report.

Data Security Policy | High-Performance Computing | NREL

Science.gov Websites

to use its high-performance computing (HPC) systems. NREL HPC systems are operated as research systems and may only contain data related to scientific research. These systems are categorized as low per sensitive or non-sensitive. One example of sensitive data would be personally identifiable information (PII

High temperature performance of soy-based adhesives

Treesearch

Jane L. O’Dell; Christopher G. Hunt; Charles R. Frihart

2013-01-01

We studied the high temperature performance of soy meal processed to different protein concentrations (flour, concentrate, and isolate), as well as formulated soy-based adhesives, and commercial nonsoy adhesives for comparison. No thermal transitions were seen in phenol-resorcinol-formaldehyde (PRF) or soy-phenol-formaldehyde (SoyPF) or in as-received soy flour...

Teacher Performance Trajectories in High- and Lower-Poverty Schools

ERIC Educational Resources Information Center

Xu, Zeyu; Özek, Umut; Hansen, Michael

2015-01-01

This study explores whether teacher performance trajectory over time differs by school-poverty settings. Focusing on elementary school mathematics teachers in North Carolina and Florida, we find no systematic relationship between school student poverty rates and teacher performance trajectories. In both high- (=60% free/reduced-price lunch [FRPL])…

Study of a pursuit-evasion guidance law for high performance aircraft

NASA Technical Reports Server (NTRS)

Williams, Peggy S.; Menon, P. K. A.; Antoniewicz, Robert F.; Duke, Eugene L.

1989-01-01

The study of a one-on-one aircraft pursuit-evasion guidance scheme for high-performance aircraft is discussed. The research objective is to implement a guidance law derived earlier using differential game theory in conjunction with the theory of feedback linearization. Unlike earlier research in this area, the present formulation explicitly recognizes the two-sided nature of the pursuit-evasion scenario. The present research implements the guidance law in a realistic model of a modern high-performance fighter aircraft. Also discussed are the details of the guidance law, implementation in a highly detailed simulation of a high-performance fighter, and numerical results for two engagement geometries. Modifications of the guidance law for onboard implementation is also discussed.

Panoscopic approach for high-performance Te-doped skutterudite

DOE PAGES

Liang, Tao; Su, Xianli; Yan, Yonggao; ...

2017-02-24

One-step plasma-activated sintering (OS-PAS) fabrication of single-phase high-performance CoSb 3-based skutterudite thermoelectric material with a hierarchical structure on a time scale of a few minutes is first reported here. The formation mechanism of the CoSb 3 phase and the effects of the current and pressure fields on the phase transformation and microstructure evolution are studied in the one-step PAS process. The application of the panoscopic approach to this system and its effect on the transport properties are investigated. The results show that the hierarchical structure forms during the formation of the skutterudite phase under the effects of both current andmore » sintering pressure. The samples fabricated by the OS-PAS technique have defined hierarchical structures, which scatter phonons more intensely over a broader range of frequencies and significantly reduce the lattice thermal conductivity. High-performance bulk Te-doped skutterudite with the maximum ZT of 1.1 at 820 K for the composition CoSb 2.875Te 0.125 was obtained. Such high ZT values rival those obtained from single filled skutterudites. As a result, this newly developed OS-PAS technique enhances the thermoelectric performance, dramatically shortens the synthesis period and provides a facile method for obtaining hierarchical thermoelectric materials on a large scale.« less

Achieving High Performance on the i860 Microprocessor

NASA Technical Reports Server (NTRS)

Lee, King; Kutler, Paul (Technical Monitor)

1998-01-01

The i860 is a high performance microprocessor used in the Intel Touchstone project. This paper proposes a paradigm for programming the i860 that is modelled on the vector instructions of the Cray computers. Fortran callable assembler subroutines were written that mimic the concurrent vector instructions of the Cray. Cache takes the place of vector registers. Using this paradigm we have achieved twice the performance of compiled code on a traditional solve.

Performance of high performance concrete (HPC) in low pH and sulfate environment.

DOT National Transportation Integrated Search

2013-05-01

The goal of this research is to determine the impact of low pH and sulfate environment on high-performance concrete (HPC) and if the current structural and materials specifications provide adequate protections for concrete structures to meet the 75-y...

Benchmarking high performance computing architectures with CMS’ skeleton framework

NASA Astrophysics Data System (ADS)

Sexton-Kennedy, E.; Gartung, P.; Jones, C. D.

2017-10-01

In 2012 CMS evaluated which underlying concurrency technology would be the best to use for its multi-threaded framework. The available technologies were evaluated on the high throughput computing systems dominating the resources in use at that time. A skeleton framework benchmarking suite that emulates the tasks performed within a CMSSW application was used to select Intel’s Thread Building Block library, based on the measured overheads in both memory and CPU on the different technologies benchmarked. In 2016 CMS will get access to high performance computing resources that use new many core architectures; machines such as Cori Phase 1&2, Theta, Mira. Because of this we have revived the 2012 benchmark to test it’s performance and conclusions on these new architectures. This talk will discuss the results of this exercise.

Integrating Reconfigurable Hardware-Based Grid for High Performance Computing

PubMed Central

Dondo Gazzano, Julio; Sanchez Molina, Francisco; Rincon, Fernando; López, Juan Carlos

2015-01-01

FPGAs have shown several characteristics that make them very attractive for high performance computing (HPC). The impressive speed-up factors that they are able to achieve, the reduced power consumption, and the easiness and flexibility of the design process with fast iterations between consecutive versions are examples of benefits obtained with their use. However, there are still some difficulties when using reconfigurable platforms as accelerator that need to be addressed: the need of an in-depth application study to identify potential acceleration, the lack of tools for the deployment of computational problems in distributed hardware platforms, and the low portability of components, among others. This work proposes a complete grid infrastructure for distributed high performance computing based on dynamically reconfigurable FPGAs. Besides, a set of services designed to facilitate the application deployment is described. An example application and a comparison with other hardware and software implementations are shown. Experimental results show that the proposed architecture offers encouraging advantages for deployment of high performance distributed applications simplifying development process. PMID:25874241

High performance concrete in a bridge in Richlands, Virginia

DOT National Transportation Integrated Search

1999-09-01

The Virginia Department of Transportation built a high-performance concrete (HPC) bridge with high-strength and low-permeability concrete in Richlands. The beams had a minimum compressive strength of 69 MPa (10,000 psi) at 28 days and large, 15 mm (0...

Broadband and tunable high-performance microwave absorption of an ultralight and highly compressible graphene foam.

PubMed

Zhang, Yi; Huang, Yi; Zhang, Tengfei; Chang, Huicong; Xiao, Peishuang; Chen, Honghui; Huang, Zhiyu; Chen, Yongsheng

2015-03-25

The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated. Simply via physical compression, the microwave absorption performance can be tuned. The qualified bandwidth coverage of 93.8% (60.5 GHz/64.5 GHz) is achieved for the GF under 90% compressive strain (1.0 mm thickness). This mainly because of the 3D conductive network. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Performance Computer Cluster for Theoretical Studies of Roaming in Chemical Reactions

DTIC Science & Technology

2016-08-30

High-performance Computer Cluster for Theoretical Studies of Roaming in Chemical Reactions A dedicated high-performance computer cluster was...SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Computer cluster ...peer-reviewed journals: Final Report: High-performance Computer Cluster for Theoretical Studies of Roaming in Chemical Reactions Report Title A dedicated

Predicting High-Power Performance in Professional Cyclists.

PubMed

Sanders, Dajo; Heijboer, Mathieu; Akubat, Ibrahim; Meijer, Kenneth; Hesselink, Matthijs K

2017-03-01

To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists. Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model. The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model. This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

Experimental Evaluation of High Performance Integrated Heat Pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, William A; Berry, Robert; Durfee, Neal

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 themore » 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.« less

15 CFR 743.2 - High performance computers: Post shipment verification reporting.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 2 2012-01-01 2012-01-01 false High performance computers: Post... Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL REPORTING § 743.2 High performance computers: Post shipment verification...

15 CFR 743.2 - High performance computers: Post shipment verification reporting.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false High performance computers: Post... Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL REPORTING § 743.2 High performance computers: Post shipment verification...

15 CFR 743.2 - High performance computers: Post shipment verification reporting.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false High performance computers: Post... Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL REPORTING § 743.2 High performance computers: Post shipment verification...

15 CFR 743.2 - High performance computers: Post shipment verification reporting.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false High performance computers: Post... Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL REPORTING § 743.2 High performance computers: Post shipment verification...

15 CFR 743.2 - High performance computers: Post shipment verification reporting.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 15 Commerce and Foreign Trade 2 2014-01-01 2014-01-01 false High performance computers: Post... Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL REPORTING AND NOTIFICATION § 743.2 High performance computers: Post shipment...

High-performance computing with quantum processing units

DOE PAGES

Britt, Keith A.; Oak Ridge National Lab.; Humble, Travis S.; ...

2017-03-01

The prospects of quantum computing have driven efforts to realize fully functional quantum processing units (QPUs). Recent success in developing proof-of-principle QPUs has prompted the question of how to integrate these emerging processors into modern high-performance computing (HPC) systems. We examine how QPUs can be integrated into current and future HPC system architectures by accounting for func- tional and physical design requirements. We identify two integration pathways that are differentiated by infrastructure constraints on the QPU and the use cases expected for the HPC system. This includes a tight integration that assumes infrastructure bottlenecks can be overcome as well asmore » a loose integration that as- sumes they cannot. We find that the performance of both approaches is likely to depend on the quantum interconnect that serves to entangle multiple QPUs. As a result, we also identify several challenges in assessing QPU performance for HPC, and we consider new metrics that capture the interplay between system architecture and the quantum parallelism underlying computational performance.« less

High-performance computing with quantum processing units

DOE Office of Scientific and Technical Information (OSTI.GOV)

Britt, Keith A.; Oak Ridge National Lab.; Humble, Travis S.

The prospects of quantum computing have driven efforts to realize fully functional quantum processing units (QPUs). Recent success in developing proof-of-principle QPUs has prompted the question of how to integrate these emerging processors into modern high-performance computing (HPC) systems. We examine how QPUs can be integrated into current and future HPC system architectures by accounting for func- tional and physical design requirements. We identify two integration pathways that are differentiated by infrastructure constraints on the QPU and the use cases expected for the HPC system. This includes a tight integration that assumes infrastructure bottlenecks can be overcome as well asmore » a loose integration that as- sumes they cannot. We find that the performance of both approaches is likely to depend on the quantum interconnect that serves to entangle multiple QPUs. As a result, we also identify several challenges in assessing QPU performance for HPC, and we consider new metrics that capture the interplay between system architecture and the quantum parallelism underlying computational performance.« less

High-performance fiber/epoxy composite pressure vessels

NASA Technical Reports Server (NTRS)

Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.; Toland, R. H.

1978-01-01

Activities described include: (1) determining the applicability of an ultrahigh-strength graphite fiber to composite pressure vessels; (2) defining the fatigue performance of thin-titanium-lined, high-strength graphite/epoxy pressure vessel; (3) selecting epoxy resin systems suitable for filament winding; (4) studying the fatigue life potential of Kevlar 49/epoxy pressure vessels; and (5) developing polymer liners for composite pressure vessels. Kevlar 49/epoxy and graphite fiber/epoxy pressure vessels, 10.2 cm in diameter, some with aluminum liners and some with alternation layers of rubber and polymer were fabricated. To determine liner performance, vessels were subjected to gas permeation tests, fatigue cycling, and burst tests, measuring composite performance, fatigue life, and leak rates. Both the metal and the rubber/polymer liner performed well. Proportionately larger pressure vessels (20.3 and 38 cm in diameter) were made and subjected to the same tests. In these larger vessels, line leakage problems with both liners developed the causes of the leaks were identified and some solutions to such liner problems are recommended.

Fabrication of highly ordered polyaniline nanocone on pristine graphene for high-performance supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Song, Ningning; Wang, Wucong; Wu, Yue; Xiao, Ding; Zhao, Yaping

2018-04-01

The hybrids of pristine graphene with polyaniline were synthesized by in situ polymerizations for making a high-performance supercapacitor. The formed high-ordered PANI nanocones were vertically aligned on the graphene sheets. The length of the PANI nanocones increased with the concentration of aniline monomer. The specific capacitance of the hybrids electrode in the three-electrode system was measured as high as 481 F/g at a current density of 0.1 A/g, and its stability remained 87% after constant charge-discharge 10000 cycles at a current density of 1 A/g. This outstanding performance is attributed to the coupling effects of the pristine graphene and the hierarchical structure of the PANI possessing high specific surface area. The unique structure of the PANI provided more charge transmission pathways and fast charge-transfer speed of electrons to the pristine graphene because of its large specific area exposed to the electrolyte. The hybrid is expected to have potential applications in supercapacitor electrodes.

Variational formulation of high performance finite elements: Parametrized variational principles

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.; Militello, Carmello

1991-01-01

High performance elements are simple finite elements constructed to deliver engineering accuracy with coarse arbitrary grids. This is part of a series on the variational basis of high-performance elements, with emphasis on those constructed with the free formulation (FF) and assumed natural strain (ANS) methods. Parametrized variational principles that provide a foundation for the FF and ANS methods, as well as for a combination of both are presented.

Middle School Concept Helps High-Poverty Schools Become High-Performing Schools

ERIC Educational Resources Information Center

Picucci, Ali Callicoatte; Brownson, Amanda; Kahlert, Rahel; Sobel, Andrew

2004-01-01

The results of a study conducted by the Charles A. Dana Center at the University of Texas at Austin for the U.S. Department of Education during the 2001-02 school year showed that elements of the middle school concept can lead to improved student performance, even in high-poverty schools. This article describes common elements of the middle school…

Factors associated with high-quality/low-cost hospital performance.

PubMed

Jiang, H Joanna; Friedman, Bernard; Begun, James W

2006-01-01

This study explores organizational and market characteristics associated with superior hospital performance in both quality and cost of care, using the Healthcare Cost and Utilization Project State Inpatient Databases for ten states in 1997 and 2001. After controlling for a variety of patient factors, we found that for-profit ownership, hospital competition, and the number of HMOs were positively associated with the likelihood of attaining high-quality/low-cost performance. Furthermore, we examined interactions between organizational and market characteristics and identified a number of significant interactions. For example, the positive likelihood associated with for-profit hospitals diminished in markets with high HMO penetration.

High-performance web services for querying gene and variant annotation.

PubMed

Xin, Jiwen; Mark, Adam; Afrasiabi, Cyrus; Tsueng, Ginger; Juchler, Moritz; Gopal, Nikhil; Stupp, Gregory S; Putman, Timothy E; Ainscough, Benjamin J; Griffith, Obi L; Torkamani, Ali; Whetzel, Patricia L; Mungall, Christopher J; Mooney, Sean D; Su, Andrew I; Wu, Chunlei

2016-05-06

Efficient tools for data management and integration are essential for many aspects of high-throughput biology. In particular, annotations of genes and human genetic variants are commonly used but highly fragmented across many resources. Here, we describe MyGene.info and MyVariant.info, high-performance web services for querying gene and variant annotation information. These web services are currently accessed more than three million times permonth. They also demonstrate a generalizable cloud-based model for organizing and querying biological annotation information. MyGene.info and MyVariant.info are provided as high-performance web services, accessible at http://mygene.info and http://myvariant.info . Both are offered free of charge to the research community.

Simulating Effects of High Angle of Attack on Turbofan Engine Performance

NASA Technical Reports Server (NTRS)

Liu, Yuan; Claus, Russell W.; Litt, Jonathan S.; Guo, Ten-Huei

2013-01-01

A method of investigating the effects of high angle of attack (AOA) flight on turbofan engine performance is presented. The methodology involves combining a suite of diverse simulation tools. Three-dimensional, steady-state computational fluid dynamics (CFD) software is used to model the change in performance of a commercial aircraft-type inlet and fan geometry due to various levels of AOA. Parallel compressor theory is then applied to assimilate the CFD data with a zero-dimensional, nonlinear, dynamic turbofan engine model. The combined model shows that high AOA operation degrades fan performance and, thus, negatively impacts compressor stability margins and engine thrust. In addition, the engine response to high AOA conditions is shown to be highly dependent upon the type of control system employed.

Next-generation fiber lasers enabled by high-performance components

NASA Astrophysics Data System (ADS)

Kliner, D. A. V.; Victor, B.; Rivera, C.; Fanning, G.; Balsley, D.; Farrow, R. L.; Kennedy, K.; Hampton, S.; Hawke, R.; Soukup, E.; Reynolds, M.; Hodges, A.; Emery, J.; Brown, A.; Almonte, K.; Nelson, M.; Foley, B.; Dawson, D.; Hemenway, D. M.; Urbanek, W.; DeVito, M.; Bao, L.; Koponen, J.; Gross, K.

2018-02-01

Next-generation industrial fiber lasers enable challenging applications that cannot be addressed with legacy fiber lasers. Key features of next-generation fiber lasers include robust back-reflection protection, high power stability, wide power tunability, high-speed modulation and waveform generation, and facile field serviceability. These capabilities are enabled by high-performance components, particularly pump diodes and optical fibers, and by advanced fiber laser designs. We summarize the performance and reliability of nLIGHT diodes, fibers, and next-generation industrial fiber lasers at power levels of 500 W - 8 kW. We show back-reflection studies with up to 1 kW of back-reflected power, power-stability measurements in cw and modulated operation exhibiting sub-1% stability over a 5 - 100% power range, and high-speed modulation (100 kHz) and waveform generation with a bandwidth 20x higher than standard fiber lasers. We show results from representative applications, including cutting and welding of highly reflective metals (Cu and Al) for production of Li-ion battery modules and processing of carbon fiber reinforced polymers.

Performance measurement and modeling of component applications in a high performance computing environment : a case study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Robert C.; Ray, Jaideep; Malony, A.

2003-11-01

We present a case study of performance measurement and modeling of a CCA (Common Component Architecture) component-based application in a high performance computing environment. We explore issues peculiar to component-based HPC applications and propose a performance measurement infrastructure for HPC based loosely on recent work done for Grid environments. A prototypical implementation of the infrastructure is used to collect data for a three components in a scientific application and construct performance models for two of them. Both computational and message-passing performance are addressed.

User Account Passwords | High-Performance Computing | NREL

Science.gov Websites

Account Passwords User Account Passwords For NREL's high-performance computing (HPC) systems, learn about user account password requirements and how to set up, log in, and change passwords. Password Logging In the First Time After you request an HPC user account, you'll receive a temporary password. Set

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.

Technology Leadership in Malaysia's High Performance School

ERIC Educational Resources Information Center

Yieng, Wong Ai; Daud, Khadijah Binti

2017-01-01

Headmaster as leader of the school also plays a role as a technology leader. This applies to the high performance schools (HPS) headmaster as well. The HPS excel in all aspects of education. In this study, researcher is interested in examining the role of the headmaster as a technology leader through interviews with three headmasters of high…

Microspherical polyaniline/graphene nanocomposites for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Cao, Hailiang; Zhou, Xufeng; Zhang, Yiming; Chen, Liang; Liu, Zhaoping

2013-12-01

Polyaniline/graphene nanocomposites with microspherical morphology and porous structure are prepared as electrode materials for supercapacitors. Using few-layer graphene obtained by liquid phase exfoliation of graphite as the raw material, porous graphene microspheres are produced by spray drying, and are then employed as the substrates for the growth of polyaniline nanowire arrays by in situ polymerization. In the composite, interconnected graphene sheets with few structural defects constitute a high-efficient conductive network to improve the electrical conductivity of polyaniline. Furthermore, the microspherical architecture prevents restacking of polyaniline/graphene composite nanosheets, thus facilitates fast diffusion of electrolytes. Consequently, the nanocomposite exhibits excellent electrochemical performance. A specific capacitance of 338 F g-1 is reached in 1 M H2SO4 at a scan rate of 20 mV s-1, and a high capacity retention rate of 87.4% after 10,000 cycles at a current density of 3 A g-1 can be achieved, which suggests that the polyaniline/graphene composite with such kind of 3D architecture is a promising electrode material for high-performance supercapacitors.

Low Cost High Performance Nanostructured Spectrally Selective Coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Sungho

2017-04-05

Sunlight absorbing coating is a key enabling technology to achieve high-temperature high-efficiency concentrating solar power operation. A high-performance solar absorbing material must simultaneously meet all the following three stringent requirements: high thermal efficiency (usually measured by figure of merit), high-temperature durability, and oxidation resistance. The objective of this research is to employ a highly scalable process to fabricate and coat black oxide nanoparticles onto solar absorber surface to achieve ultra-high thermal efficiency. Black oxide nanoparticles have been synthesized using a facile process and coated onto absorber metal surface. The material composition, size distribution and morphology of the nanoparticle are guidedmore » by numeric modeling. Optical and thermal properties have been both modeled and measured. High temperature durability has been achieved by using nanocomposites and high temperature annealing. Mechanical durability on thermal cycling have also been investigated and optimized. This technology is promising for commercial applications in next-generation high-temperature concentration solar power (CSP) plants.« less

Benchmarking high performance computing architectures with CMS’ skeleton framework

DOE PAGES

Sexton-Kennedy, E.; Gartung, P.; Jones, C. D.

2017-11-23

Here, in 2012 CMS evaluated which underlying concurrency technology would be the best to use for its multi-threaded framework. The available technologies were evaluated on the high throughput computing systems dominating the resources in use at that time. A skeleton framework benchmarking suite that emulates the tasks performed within a CMSSW application was used to select Intel’s Thread Building Block library, based on the measured overheads in both memory and CPU on the different technologies benchmarked. In 2016 CMS will get access to high performance computing resources that use new many core architectures; machines such as Cori Phase 1&2, Theta,more » Mira. Because of this we have revived the 2012 benchmark to test it’s performance and conclusions on these new architectures. This talk will discuss the results of this exercise.« less

Benchmarking high performance computing architectures with CMS’ skeleton framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sexton-Kennedy, E.; Gartung, P.; Jones, C. D.

Here, in 2012 CMS evaluated which underlying concurrency technology would be the best to use for its multi-threaded framework. The available technologies were evaluated on the high throughput computing systems dominating the resources in use at that time. A skeleton framework benchmarking suite that emulates the tasks performed within a CMSSW application was used to select Intel’s Thread Building Block library, based on the measured overheads in both memory and CPU on the different technologies benchmarked. In 2016 CMS will get access to high performance computing resources that use new many core architectures; machines such as Cori Phase 1&2, Theta,more » Mira. Because of this we have revived the 2012 benchmark to test it’s performance and conclusions on these new architectures. This talk will discuss the results of this exercise.« less