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Sample records for sigma-delta modulator performances

  1. Noise Simulation of Continuous-Time {sigma}{delta} Modulators

    SciTech Connect

    Arias, J.; Quintanilla, L.; Bisbal, D.; San Pablo, J.; Enriquez, L.; Vicente, J.; Barbolla, J.

    2005-08-25

    In this work, an approach for the simulation of the effect of noise sources in the performance of continuous-time {delta}{sigma} modulators is presented. Electrical noise including thermal noise, 1/f noise and clock jitter are included in a simulation program and their impact on the system performance is analyzed.

  2. SEMICONDUCTOR INTEGRATED CIRCUITS: Study and analysis of coefficient mismatch in a MASH21 sigma-delta modulator

    NASA Astrophysics Data System (ADS)

    Binjie, Ge; Xin'an, Wang; Xing, Zhang; Xiaoxing, Feng; Qingqin, Wang

    2010-01-01

    The quantization noise leakage of the first stage in a MASH21 sigma-delta modulator is analyzed. The results show that the finite DC gain of the opamp is the main reason for noise leakage, and finite GBW and SR only generate harmonic distortion. The relationship between DC gain and leakage is modeled and conclusions on design criteria are reached. As an example, a MASH21 modulator for a digital audio application is realized. This modulator, fabricated in an 0.18 μm mixed signal process, achieves an SNDR of 91 dB with 1.8 V supply, which verifies the analysis and design criteria.

  3. Interference Resilient Sigma Delta-Based Pulse Oximeter.

    PubMed

    Shokouhian, Mohsen; Morling, Richard; Kale, Izzet

    2016-06-01

    Ambient light and optical interference can severely affect the performance of pulse oximeters. The deployment of a robust modulation technique to drive the pulse oximeter LEDs can reduce these unwanted effects and increases the resilient of the pulse oximeter against artificial ambient light. The time division modulation technique used in conventional pulse oximeters can not remove the effect of modulated light coming from surrounding environment and this may cause huge measurement error in pulse oximeter readings. This paper presents a novel cross-coupled sigma delta modulator which ensures that measurement accuracy will be more robust in comparison with conventional fixed-frequency oximeter modulation technique especially in the presence of pulsed artificial ambient light. Moreover, this novel modulator gives an extra control over the pulse oximeter power consumption leading to improved power management.

  4. Interference Resilient Sigma Delta-Based Pulse Oximeter.

    PubMed

    Shokouhian, Mohsen; Morling, Richard; Kale, Izzet

    2016-06-01

    Ambient light and optical interference can severely affect the performance of pulse oximeters. The deployment of a robust modulation technique to drive the pulse oximeter LEDs can reduce these unwanted effects and increases the resilient of the pulse oximeter against artificial ambient light. The time division modulation technique used in conventional pulse oximeters can not remove the effect of modulated light coming from surrounding environment and this may cause huge measurement error in pulse oximeter readings. This paper presents a novel cross-coupled sigma delta modulator which ensures that measurement accuracy will be more robust in comparison with conventional fixed-frequency oximeter modulation technique especially in the presence of pulsed artificial ambient light. Moreover, this novel modulator gives an extra control over the pulse oximeter power consumption leading to improved power management. PMID:26742140

  5. Parameter optimization for a high-order band-pass continuous-time sigma-delta modulator MEMS gyroscope using a genetic algorithm approach

    NASA Astrophysics Data System (ADS)

    Chen, Fang; Chang, Honglong; Yuan, Weizheng; Wilcock, Reuben; Kraft, Michael

    2012-10-01

    This paper describes a novel multiobjective parameter optimization method based on a genetic algorithm (GA) for the design of a sixth-order continuous-time, force feedback band-pass sigma-delta modulator (BP-ΣΔM) interface for the sense mode of a MEMS gyroscope. The design procedure starts by deriving a parameterized Simulink model of the BP-ΣΔM gyroscope interface. The system parameters are then optimized by the GA. Consequently, the optimized design is tested for robustness by a Monte Carlo analysis to find a solution that is both optimal and robust. System level simulations result in a signal-to-noise ratio (SNR) larger than 90 dB in a bandwidth of 64 Hz with a 200° s-1 angular rate input signal; the noise floor is about -100 dBV Hz-1/2. The simulations are compared to measured data from a hardware implementation. For zero input rotation with the gyroscope operating at atmospheric pressure, the spectrum of the output bitstream shows an obvious band-pass noise shaping and a deep notch at the gyroscope resonant frequency. The noise floor of measured power spectral density (PSD) of the output bitstream agrees well with simulation of the optimized system level model. The bias stability, rate sensitivity and nonlinearity of the gyroscope controlled by an optimized BP-ΣΔM closed-loop interface are 34.15° h-1, 22.3 mV °-1 s-1, 98 ppm, respectively. This compares to a simple open-loop interface for which the corresponding values are 89° h-1, 14.3 mV °-1 s-1, 7600 ppm, and a nonoptimized BP-ΣΔM closed-loop interface with corresponding values of 60° h-1, 17 mV °-1 s-1, 200 ppm.

  6. A digital 25 µm pixel-pitch uncooled amorphous silicon TEC-less VGA IRFPA with massive parallel Sigma-Delta-ADC readout

    NASA Astrophysics Data System (ADS)

    Weiler, Dirk; Russ, Marco; Würfel, Daniel; Lerch, Renee; Yang, Pin; Bauer, Jochen; Vogt, Holger

    2010-04-01

    This paper presents an advanced 640 x 480 (VGA) IRFPA based on uncooled microbolometers with a pixel-pitch of 25μm developed by Fraunhofer-IMS. The IRFPA is designed for thermal imaging applications in the LWIR (8 .. 14μm) range with a full-frame frequency of 30 Hz and a high sensitivity with NETD < 100 mK @ f/1. A novel readout architecture which utilizes massively parallel on-chip Sigma-Delta-ADCs located under the microbolometer array results in a high performance digital readout. Sigma-Delta-ADCs are inherently linear. A high resolution of 16 bit for a secondorder Sigma-Delta-modulator followed by a third-order digital sinc-filter can be obtained. In addition to several thousand Sigma-Delta-ADCs the readout circuit consists of a configurable sequencer for controlling the readout clocking signals and a temperature sensor for measuring the temperature of the IRFPA. Since packaging is a significant part of IRFPA's price Fraunhofer-IMS uses a chip-scaled package consisting of an IR-transparent window with antireflection coating and a soldering frame for maintaining the vacuum. The IRFPAs are completely fabricated at Fraunhofer-IMS on 8" CMOS wafers with an additional surface micromachining process. In this paper the architecture of the readout electronics, the packaging, and the electro-optical performance characterization are presented.

  7. Low-power adaptive spike detector based on a sigma-delta control loop.

    PubMed

    Gagnon-Turcotte, G; Sawan, M; Gosselin, B

    2015-08-01

    This paper presents a resources-optimized digital action potential (AP) detector featuring an adaptive threshold based on a new Sigma-delta control loop. The proposed AP detector is optimized for utilizing low hardware resources, which makes it suitable for implementation on most popular low-power microcontrollers units (MCU). The adaptive threshold is calculated using a digital control loop based on a Sigma-delta modulator that precisely estimates the standard deviation of the amplitude of the neuronal signal. The detector was implemented on a popular low-power MCU and fully characterized experimentally using previously recorded neural signals with different signal-to-noise ratios. A comparison of the obtained results with other thresholding approaches shows that the proposed method can compete with high performance and highly resources demanding spike detection approaches while achieving up to 100% of true positive detection rate at high SNR, and up to 63% for an SNR as low as 0 dB, while necessitating an execution time as low as 11 μs with the MCU operating at 8 MHz. PMID:26736719

  8. The signal to noise and distortion ratio for sigma delta ADC for SDR 3G/4G mobile receivers

    NASA Astrophysics Data System (ADS)

    Trivedi, Preeti; Verma, Ajay

    2013-01-01

    In this paper, we propose a Simulation for the test of SNDR (Signal to noise and Distortion ratio) in Sigma Delta ADC for SDR 3G and 4G mobile Receivers. Now a days, SNDR is one of the most important parameter which directly effects the performance of ADC. Simulation results show the Capability of the simulink to obtain SNDR for a 8 bit and 10 bit audio Sigma delta ADC. SNDR of ADC will always be less than SNR. The simulation model of second order Sigma Delta ADC is given in the paper. The SNR and SNDR have been taken into account.

  9. Design of a Low-Light-Level Image Sensor with On-Chip Sigma-Delta Analog-to- Digital Conversion

    NASA Technical Reports Server (NTRS)

    Mendis, Sunetra K.; Pain, Bedabrata; Nixon, Robert H.; Fossum, Eric R.

    1993-01-01

    The design and projected performance of a low-light-level active-pixel-sensor (APS) chip with semi-parallel analog-to-digital (A/D) conversion is presented. The individual elements have been fabricated and tested using MOSIS* 2 micrometer CMOS technology, although the integrated system has not yet been fabricated. The imager consists of a 128 x 128 array of active pixels at a 50 micrometer pitch. Each column of pixels shares a 10-bit A/D converter based on first-order oversampled sigma-delta (Sigma-Delta) modulation. The 10-bit outputs of each converter are multiplexed and read out through a single set of outputs. A semi-parallel architecture is chosen to achieve 30 frames/second operation even at low light levels. The sensor is designed for less than 12 e^- rms noise performance.

  10. Design Principles of A Sigma-delta Flux-gate Magnetometer

    NASA Astrophysics Data System (ADS)

    Magnes, W.; Valavanoglou, A.; Pierce, D.; Frank, A.; Schwingenschuh, K.

    A state-of-the-art flux-gate magnetometer is characterised by magnetic field resolution of several pT in a wide frequency range, low power consumption, low weight and high robustness. Therefore, flux-gate magnetometers are frequently used for ground-based Earth's field observation as well as for measurements aboard scientific space missions. But both traditional analogue and recently developed digital flux-gate magnetometers need low power and high-resolution analogue-to-digital converters for signal quan- tization. The disadvantage of such converters is the low radiation hardness. This fact has led to the idea of combining a traditional analogue flux-gate regulation circuit with that of a discretely realized sigma-delta converter in order to get a radiation hard and further miniaturized magnetometer. The name sigma-delta converter is derived from putting an integrator in front of a 1-bit delta modulator which forms the sigma-delta loop. It is followed by a digital decimation filter realized in a field-programmable gate array (FPGA). The flux-gate regulation and the sigma-delta loop are quite similar in the way of realizing the integrator and feedback circuit, which makes it easy to com- bine these two systems. The presented talk deals with the design principles and the results of a first bread board model.

  11. ROIC with on-chip sigma-delta AD converter for HgCdTe e-APD FPA

    NASA Astrophysics Data System (ADS)

    Chen, Guoqiang; Zhang, Junling; Wang, Pan; Zhou, Jie; Gao, Lei; Ding, Ruijun

    2013-10-01

    HgCdTe electron injection avalanche photodiodes (e-APDs) work at linear mode. A weak optical current signal is amplified orders of magnitude due to the internal avalanche mechanism and it has been demonstrated to be one of the most promising methods to focal-plane arrays (FPAs) for low-flux like hyper-spectral imaging and high-speed applications such as active imaging. This paper presents the design of a column-shared ADC for cooled e-APDs FPA. Designing a digital FPA requires fulfilling very stringent requirements in terms of power consumption, silicon area and speed. Among the various ADC architectures sigma-delta conversion is a promising solution for high-performance and medium size FPA such as 128×128. The performance of Sigma-delta ADC rather relies on the modulator structure which set over-sampling and noise shaping characteristics than on critical analog circuits. This makes them quite robust and flexible. A multistage noise shaping (MASH) 2-1 single bit architecture sigma-delta conversion with switched-capacitor circuits is designed for column-shared ADC, which is implanted in the GLOBALFOUNDRIES 0.35um CMOS process with 4-poly and 4-metal on the basis of a 100um pixel pitch. It operates under 3.3V supply and the output range of the quantizer is 2V. A quantization noise subtraction circuit in modulator is designed to subtract the quantization noise of first-stage modulator. The quantization noise of the modulator is shaped by a high-pass filter. The silicon area and power consumption are mainly determined by the decimation low pass filter. A cascaded integrator-comb (CIC) filter is designed as the digital decimator filter. CIC filter requires no multipliers and use limited storage thereby leading to more economical hardware implementation. The register word length of the filter in each stage is carefully dimensioned in order to minimize the required hardware. Furthermore, the digital filters operate with a reduced supply voltage to 1.5V. Simulation

  12. [Application of over sampling sigma-delta A/D in DOAS system].

    PubMed

    Li, Su-wen; Liu, Wen-qing; Xie, Pin-hua

    2006-12-01

    Differential optical absorption spectroscopy (DOAS) has become a widely used method to measure trace gases in the atmosphere. Concentration of trace gases is retrieved using least-squares fits of reference spectra to the measurement spectra. The measurement precision not only depends on the measurement precision of spectra and the noise of instrument and disturbing of other gases in measuring band, but suffers the influence of signal sampling and pre-processing. The present paper simply introduced DOAS measuring principle and the setup of instrument and put forward improving method-the technology of over sampling sigma- deltaA/D. Using the sigma-delta modulator structure to shape noises together with the over sampling technology can doubly restrain quantifying noises, which can improve the signal-to-noise ratio within the measuring band. So the measurement precision of DOAS system is improved with this technology. PMID:17361733

  13. Hybridization of a sigma-delta-based CMOS hybrid detector

    NASA Astrophysics Data System (ADS)

    Kolb, K. E.; Stoffel, N. C.; Douglas, B.; Maloney, C. W.; Raisanen, A. D.; Ashe, B.; Figer, D. F.; Tamagawa, T.; Halpern, B.; Ignjatovic, Zeljko

    2010-07-01

    The Rochester Imaging Detector Laboratory, University of Rochester, Infotonics Technology Center, and Jet Process Corporation developed a hybrid silicon detector with an on-chip sigma-delta (ΣΔ) ADC. This paper describes the process and reports the results of developing a fabrication process to robustly produce high-quality bump bonds to hybridize a back-illuminated detector with its ΣΔ ADC. The design utilizes aluminum pads on both the readout circuit and the photodiode array with interconnecting indium bumps between them. The development of the bump bonding process is discussed, including specific material choices, interim process structures, and final functionality. Results include measurements of bond integrity, cross-wafer uniformity of indium bumps, and effects of process parameters on the final product. Future plans for improving the bump bonding process are summarized.

  14. Adjustable Nyquist-rate System for Single-Bit Sigma-Delta ADC with Alternative FIR Architecture

    NASA Astrophysics Data System (ADS)

    Frick, Vincent; Dadouche, Foudil; Berviller, Hervé

    2016-09-01

    This paper presents a new smart and compact system dedicated to control the output sampling frequency of an analogue-to-digital converters (ADC) based on single-bit sigma-delta (ΣΔ) modulator. This system dramatically improves the spectral analysis capabilities of power network analysers (power meters) by adjusting the ADC's sampling frequency to the input signal's fundamental frequency with a few parts per million accuracy. The trade-off between straightforwardness and performance that motivated the choice of the ADC's architecture are preliminary discussed. It particularly comes along with design considerations of an ultra-steep direct-form FIR that is optimised in terms of size and operating speed. Thanks to compact standard VHDL language description, the architecture of the proposed system is particularly suitable for application-specific integrated circuit (ASIC) implementation-oriented low-power and low-cost power meter applications. Field programmable gate array (FPGA) prototyping and experimental results validate the adjustable sampling frequency concept. They also show that the system can perform better in terms of implementation and power capabilities compared to dedicated IP resources.

  15. A digital-type fluxgate magnetometer using a sigma-delta digital-to-analog converter for a sounding rocket experiment

    NASA Astrophysics Data System (ADS)

    Iguchi, Kyosuke; Matsuoka, Ayako

    2014-07-01

    One of the design challenges for future magnetospheric satellite missions is optimizing the mass, size, and power consumption of the instruments to meet the mission requirements. We have developed a digital-type fluxgate (DFG) magnetometer that is anticipated to have significantly less mass and volume than the conventional analog-type. Hitherto, the lack of a space-grade digital-to-analog converter (DAC) with good accuracy has prevented the development of a high-performance DFG. To solve this problem, we developed a high-resolution DAC using parts whose performance was equivalent to existing space-grade parts. The developed DAC consists of a 1-bit second-order sigma-delta modulator and a fourth-order analog low-pass filter. We tested the performance of the DAC experimentally and found that it had better than 17-bits resolution in 80% of the measurement range, and the linearity error was 2-13.3 of the measurement range. We built a DFG flight model (in which this DAC was embedded) for a sounding rocket experiment as an interim step in the development of a future satellite mission. The noise of this DFG was 0.79 nTrms at 0.1-10 Hz, which corresponds to a roughly 17-bit resolution. The results show that the sigma-delta DAC and the DFG had a performance that is consistent with our optimized design, and the noise was as expected from the noise simulation. Finally, we have confirmed that the DFG worked successfully during the flight of the sounding rocket.

  16. Multichannel spike detector with an adaptive threshold based on a Sigma-delta control loop.

    PubMed

    Gagnon-Turcotte, G; Gosselin, B

    2015-08-01

    In this paper, we present a digital spike detector using an adaptive threshold which is suitable for real time processing of 32 electrophysiological channels in parallel. Such a new scheme is based on a Sigma-delta control loop that precisely estimates the standard deviation of the amplitude of the noise of the input signal to optimize the detection rate. Additionally, it is not dependent on the amplitude of the input signal thanks to a robust algorithm. The spike detector is implemented inside a Spartan-6 FPGA using low resources, only FPGA basic logic blocks, and is using a low clock frequency under 6 MHz for minimal power consumption. We present a comparison showing that the proposed system can compete with a dedicated off-line spike detection software. The whole system achieves up to 100% of true positive detection rate for SNRs down to 5 dB while achieving 62.3% of true positive detection rate for an SNR as low as -2 dB at a 150 AP/s firing rate. PMID:26737934

  17. A novel Sigma Delta ADC application oriented to test hermetic reciprocating compressors

    NASA Astrophysics Data System (ADS)

    Raush, G.; Rigola, J.; Pérez-Segarra, D.; Oliva, A.

    2004-11-01

    A novel data acquisition approach to test hermetic reciprocating compressors is presented. A non-uniformly sampled application of a SgrDgr analogue-to-digital converter was used to investigate the compressor pV diagram, together with accurate spectral analysis of pressure readings. Several previous approaches are presented and compared with the one proposed here. Different statistical comparisons have been carried out with the main objective of demonstrating the good performance of the proposal.

  18. Design and implementation of a sigma delta technology based pulse oximeter's acquisition stage

    NASA Astrophysics Data System (ADS)

    Rossi, E. E.; Peñalva, A.; Schaumburg, F.

    2011-12-01

    Pulse oximetry is a widely used tool in medical practice for estimating patient's fraction of hemoglobin bonded to oxygen. Conventional oximetry presents limitations when changes in the baseline, or low amplitude of signals involved occur. The aim of this paper is to simultaneously solve these constraints and to simplify the circuitry needed, by using ΣΔ technology. For this purpose, a board for the acquisition of the needed signals was developed, together with a PC managed software which controls it, and displays and processes in real time the information acquired. Also laboratory and field tests where designed and executed to verify the performance of this equipment in adverse situations. A simple, robust and economic instrument was achieved, capable of obtaining signals even in situations where conventional oximetry fails.

  19. Integrated Performance Testing Workshop, Modules 6 - 11

    SciTech Connect

    Leach, Janice; Torres, Teresa M.

    2012-10-01

    These modules cover performance testing of: Interior Detection Systems; Access Controls; Exterior Detection Systems; Video Assessment Systems; SNM / Contraband Detection Systems; Access Delay Elements

  20. EXOMARS Descent Module GNC Performance

    NASA Astrophysics Data System (ADS)

    Portigliotti, S.; Capuano, M.; Montagna, M.; Martella, P.; Venditto, P.

    2007-08-01

    The ExoMars mission is the first ESA led robotic mission of the Aurora Programme and combines technology development with investigations of major scientific interest. Italy is by far the major contributor to the mission through the strong support of the Italian Space Agency (ASI). ExoMars will search for traces of past and present life, characterize the Mars geochemistry and water distribution, improve the knowledge of the Mars environment and geophysics, and identify possible surface hazards to future human exploration missions. ExoMars will also validate the technology for safe Entry, Descent and Landing (EDL) of a large size Descent Module (DM) carrying a Rover with medium range surface mobility and the access to subsurface. The ExoMars project is presently undergoing its Phase B1 with Thales Alenia Space-Italia as Industrial Prime Contractor. Additionally, as Descent Module responsible, a dedicated simulation tool is under development in Thales Alenia Space-Italia, Turin site, for the end-to-end design and validation / verification of the DM Entry Descent and Landing.

  1. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-09-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, they verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. They discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  2. Performance of Skutterudite-Based Modules

    NASA Astrophysics Data System (ADS)

    Nie, G.; Suzuki, S.; Tomida, T.; Sumiyoshi, A.; Ochi, T.; Mukaiyama, K.; Kikuchi, M.; Guo, J. Q.; Yamamoto, A.; Obara, H.

    2016-08-01

    Due to their excellent thermoelectric (TE) performance, skutterudite materials have been selected by many laboratories and companies for development of TE modules to recover power from waste heat at high temperatures (300°C to 600°C). After years of effort, we have developed reliable n- and p-type skutterudite materials showing maximum figure of merit (ZT) of 1.0 at 550°C and 0.75 at 450°C, respectively. In this work, we systematically investigated the performance of a module made using these two kinds of skutterudite. We demonstrate ˜7.2% conversion efficiency for temperature of 600°C at the hot side of the module and 50°C at the cold side, and show that the module had excellent stability in the high-temperature environment. Further improving the TE performance of our skutterudites, the conversion efficiency reached ˜8.5% under the same condition.

  3. 'AMPM' - All-day module performance measurements

    NASA Astrophysics Data System (ADS)

    Gay, C. F.; Rumburg, J. E.; Wilson, J. H.

    In an earlier paper (Gay, 1982), an AM/PM daily energy delivery rating was proposed with a view to developing a new rating system for photovoltaic modules. This new rating would correspond more accurately than peak power ratings to actual energy-conversion performance under field loads and environments. Functional requirements for a practical standard photovoltaic module rating system are formulated, with attention given to the effects of changes in the module design. A specific approach to the rating format (standard daily energy delivery) and a specific institutional framework for the rating system development are suggested.

  4. A 410 μW, 70 dB SNR high performance analog front-end for portable audio application

    NASA Astrophysics Data System (ADS)

    Lan, Dai; Wenkai, Liu; Yan, Lu

    2014-10-01

    This paper describes an analog front-end (AFE) intended for portable audio application, which operates at 1 V and consumes only 410 μW. The AFE consists of a 30 dB-gain programmable gain amplifier (PGA) and a 2nd-order 3-bit sigma-delta modulator. The PGA with single input and on-chip common-mode bias voltage shows good noise-reduction performance. The modulator makes use of data weighted averaging to reduce the linearity requirements of the digital-to-analog converter in the feedback loop. The AFE is implemented in the SMIC 0.13 μm 1P8M CMOS process. The measurement results show that in a 1 V power supply, at 200 mVp-p, between 100 Hz and 20 kHz, the maximal signal-to-noise ratio is 70 dB, and the total power is 410 μW.

  5. Thin film silicon photovoltaic module performance assessment

    NASA Astrophysics Data System (ADS)

    Jennings, Christina

    1987-06-01

    This report evaluates the performance through December, 1986 of 15 commercially-available thin film silicon-hydrogen alloy PV modules manufactured by ARCO Solar, Chronar, ECD/Sovonics, and Solarex. Advances in the technology are indicated by the performance improvements associated with each generation of thin film silicon-hydrogen alloy PV modules introduced to the commercial market. Mounted at a 30 degree tilt facing due south, all of the thin film PV modules under evaluation have experienced decreased efficiency and fill factor on initial sun exposure. Midday efficiency tends to be highest during the summer and lowest during the winter. The seasonal change in midday air mass from 1.0 during the summer to 1.4 during the winter is among the factors that counteract the temperature effects and cause lowered efficiency and fill factor values during the winter.

  6. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-05-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  7. Performance Based Education. Technology Activity Modules.

    ERIC Educational Resources Information Center

    Custer, Rodney L., Ed.

    These Technology Activity Modules are designed to serve as an implementation resource for technology education teachers as they integrate technology education with Missouri's Academic Performance Standards and provide a source of activities and activity ideas that can be used to integrate and reinforce learning across the curriculum. The modules…

  8. Functional specification of the Performance Measurement (PM) module

    NASA Technical Reports Server (NTRS)

    Berliner, J. E.

    1980-01-01

    The design of the Performance Measurement Module is described with emphasis on what the PM Module would do, and what it would look like to the user. The PM Module as described could take several man-years to develop. An evolutionary approach to the implementation of the PM Module is presented which would provide an operational baseline PM Module within a few months.

  9. VIBRATING PERVAPORATION MODULES: EFFECT OF MODULE DESIGN ON PERFORMANCE

    EPA Science Inventory

    A third commercial-scale vibrating pervaporation membrane module was fabricated and evaluated for the separation of volatile organic compounds (VOCs) from aqueous solutions. Experiments with surrogate solutions of four hydrophobic VOCs (1,1,1-trichloroethane (TCA), trichloroethy...

  10. Search for Sigma--Delta hypernuclear conversion

    NASA Astrophysics Data System (ADS)

    Bukhari, Masroor Hassan Haider Shah

    This research was aimed at the study of the in-flight A=3 (K- , pi+/-) reactions leading to in situ nuclear formation of a Sigma hyperon, its interactions with nucleons, and subsequent conversion into a Λ hyperon. The analysis was based upon the data from the Brookhaven National Laboratory experiment E774 carried out at the Alternating Gradient Synchrotron. This experiment comprised a two-layered scintillation counting barrel detector and two spectrometers to detect the missing mass in the reaction on a 3He target, resulting in the Sigma hypernucleus formation. A Monte Carlo simulation of the experiment was written within the framework of the GEANT simulation tool, incorporating physics generators for all the involved channels and the technique of multiplicity tagging. The objective was to obtain and analyze the relevant multiplicities of the involved channels which could result from the primary reaction. Analysis of results from simulations and their comparison with the experimental data revealed insight into the interactions of a Sigma within the nucleus and helped identify the multiplicities which corresponded to the true Sigma-Λ conversion events. On the basis of this analysis, the three-body system SigmaNN in the s-shell and the SigmaN → ΛN conversion were investigated. In the second phase of this study, a theoretical model for the calculation of scattering parameters and relative cross section for (Sigma-.2 H) production leading to Sigma-Λ conversion was developed. This was based on the effective range expansion and a plane wave impulse approximation (PWIA) paradigm. Both the scattering and absorption amplitudes, corresponding to s-wave SigmaSigma and SigmaΛ scattering states, respectively, were calculated. Finally the parameters (and corresponding cross section) were extracted by fitting the simulated model to the experiment data. The nature of the obtained parameters and shape of the cross section shed significant light on the Sigma-Λ conversion phenomenon and its implications on the Sigma-deuteron interaction.

  11. Evaluation of PV Module Field Performance

    SciTech Connect

    Wohlgemuth, John; Silverman, Timothy; Miller, David C.; McNutt, Peter; Kempe, Michael; Deceglie, Michael

    2015-06-14

    This paper describes an effort to inspect and evaluate PV modules in order to determine what failure or degradation modes are occurring in field installations. This paper will report on the results of six site visits, including the Sacramento Municipal Utility District (SMUD) Hedge Array, Tucson Electric Power (TEP) Springerville, Central Florida Utility, Florida Solar Energy Center (FSEC), the TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification. TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification. TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification.

  12. PV cell and module performance measurement capabilities at NREL

    SciTech Connect

    Rummel, S.; Emery, K.; Field, H.; Moriarty, T.; Anderberg, A.; Dunlavy, D.; Ottoson, L.

    1998-09-01

    The Photovoltaic (PV) Cell and Module Performance Characterization team at NREL supports the entire photovoltaic community by providing: secondary calibrations of photovoltaic cells and modules; efficiency measurements with respect to a given set of standard reporting conditions; verification of contract efficiency milestones; and current versus voltage (I-V) measurements under various conditions of temperature, spectral irradiance, and total irradiance. Support is also provided to in-house programs in device fabrication, module stability, module reliability, PV systems evaluations, and alternative rating methods by performing baseline testing, specialized measurements and other assistance when required. The I-V and spectral responsivity equipment used to accomplish these tasks are described in this paper.

  13. Payload Specialist Taylor Wang performs repairs on Drop Dynamics Module

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Payload Specialist Taylor G. Wang performs a repair task on the Drop Dynamics Module (DDM) in the science module aboard the orbiter Challenger. Fellow crew members Dr. William E. Thornton (facing camera) and Don Lind are at the right of the frame.

  14. Investigation into Spectral Parameters as they Impact CPV Module Performance

    SciTech Connect

    Muller, M.; Marion, B.; Kurtz, S.; Rodriguez, J.

    2011-03-01

    The CPV industry is well aware that performance of triple junction cells depends on spectral conditions but there is a lack of data quantifying this spectral dependence at the module level. This paper explores the impact of precipitable water vapor, aerosol optical depth (AOD), and optical air mass on multiple CPV module technologies on-sun in Golden, CO.

  15. Measurements and Characterization: Cell and Module Performance (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    Capabilities fact sheet for the National Center for Photovoltaics: Measurements and Characterization -- Cell and Module Performance. One-sided sheet that includes Scope, Core Competencies and Capabilities, and Contact/Web information.

  16. Comparison of Module Performance Characterization Methods for Energy Production

    SciTech Connect

    Kroposki, B.; Marion, W.; King, D.; Boyson, W.; Kratochvil, J.

    2000-12-04

    This report compares the two methods of determining the performance of PV modules. The methods translate module performance characterized in a laboratory to actual or reference conditions using slightly different approaches. The accuracy of both methods is compared for both hourly and daily energy production over a year of data recorded at NREL in Golden, CO. The comparison of the two methods will be presented for five different PV module technologies: multicrystalline silicon (mc-Si), dual-junction amorphous silicon (a-Si/a-Si:Ge), triple-junction amorphous silicon (a-Si/a-Si/a-Si:Ge), cadmium telluride (CdTe), and copper indium diselenide (CIGSS).

  17. Precise measurement of the performance of thermoelectric modules

    NASA Astrophysics Data System (ADS)

    Díaz-Chao, Pablo; Muñiz-Piniella, Andrés; Selezneva, Ekaterina; Cuenat, Alexandre

    2016-08-01

    The potential exploitation of thermoelectric modules into mass market applications such as exhaust gas heat recovery in combustion engines requires an accurate knowledge of their performance. Further expansion of the market will also require confidence on the results provided by suppliers to end-users. However, large variation in performance and maximum operating point is observed for identical modules when tested by different laboratories. Here, we present the first metrological study of the impact of mounting and testing procedures on the precision of thermoelectric modules measurement. Variability in the electrical output due to mechanical pressure or type of thermal interface materials is quantified for the first time. The respective contribution of the temperature difference and the mean temperature to the variation in the output performance is quantified. The contribution of these factors to the total uncertainties in module characterisation is detailed.

  18. Thin film module electrical configuration versus electrical performance

    NASA Technical Reports Server (NTRS)

    Morel, D. L.

    1985-01-01

    The as made and degraded states of thin film silicon (TFS) based modules have been modelled in terms of series resistance losses. The origins of these losses lie in interface and bulk regions of the devices. When modules degrade under light exposure, increases occur in both the interface and bulk components of the loss based on series resistance. Actual module performance can thus be simulated by use of only one unknown parameter, shunt losses. Use of the simulation to optimize module design indicates that the current design of 25 cells per linear foot is near optimum. Degradation performance suggests a shift to approx. 35 cells to effect maximum output for applications not constrained to 12 volts. Earlier studies of energy based performance and tandem structures should be updated to include stability factors, not only the initial loss factor tested here, but also appropriate annealing factors.

  19. Performance of Low-Density Parity-Check Coded Modulation

    NASA Astrophysics Data System (ADS)

    Hamkins, J.

    2011-02-01

    This article presents the simulated performance of a family of nine AR4JA low-density parity-check (LDPC) codes when used with each of five modulations. In each case, the decoder inputs are codebit log-likelihood ratios computed from the received (noisy) modulation symbols using a general formula which applies to arbitrary modulations. Suboptimal soft-decision and hard-decision demodulators are also explored. Bit-interleaving and various mappings of bits to modulation symbols are considered. A number of subtle decoder algorithm details are shown to affect performance, especially in the error floor region. Among these are quantization dynamic range and step size, clipping degree-one variable nodes, "Jones clipping" of variable nodes, approximations of the min* function, and partial hard-limiting messages from check nodes. Using these decoder optimizations, all coded modulations simulated here are free of error floors down to codeword error rates below 10^{-6}. The purpose of generating this performance data is to aid system engineers in determining an appropriate code and modulation to use under specific power and bandwidth constraints, and to provide information needed to design a variable/adaptive coded modulation (VCM/ACM) system using the AR4JA codes. IPNPR Volume 42-185 Tagged File.txt

  20. Performance of Low-Density Parity-Check Coded Modulation

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon

    2010-01-01

    This paper reports the simulated performance of each of the nine accumulate-repeat-4-jagged-accumulate (AR4JA) low-density parity-check (LDPC) codes [3] when used in conjunction with binary phase-shift-keying (BPSK), quadrature PSK (QPSK), 8-PSK, 16-ary amplitude PSK (16- APSK), and 32-APSK.We also report the performance under various mappings of bits to modulation symbols, 16-APSK and 32-APSK ring scalings, log-likelihood ratio (LLR) approximations, and decoder variations. One of the simple and well-performing LLR approximations can be expressed in a general equation that applies to all of the modulation types.

  1. MSFC Skylab airlock module, volume 1. [systems design and performance

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The history and development of the Skylab Airlock Module and Payload Shroud is presented from initial concept through final design. A summary is given of the Airlock features and systems. System design and performance are presented for the Spent Stage Experiment Support Module, structure and mechanical systems, mass properties, thermal and environmental control systems, EVA/IVA suite system, electrical power system, sequential system, sequential system, and instrumentation system.

  2. Silicon high speed modulator for advanced modulation: device structures and exemplary modulator performance

    NASA Astrophysics Data System (ADS)

    Milivojevic, Biljana; Wiese, Stefan; Whiteaway, James; Raabe, Christian; Shastri, Anujit; Webster, Mark; Metz, Peter; Sunder, Sanjay; Chattin, Bill; Anderson, Sean P.; Dama, Bipin; Shastri, Kal

    2014-03-01

    Fiber optics is well established today due to the high capacity and speed, unrivaled flexibility and quality of service. However, state of the art optical elements and components are hardly scalable in terms of cost and size required to achieve competitive port density and cost per bit. Next-generation high-speed coherent optical communication systems targeting a data rate of 100-Gb/s and beyond goes along with innovations in component and subsystem areas. Consequently, by leveraging the advanced silicon micro and nano-fabrication technologies, significant progress in developing CMOS platform-based silicon photonic devices has been made all over the world. These achievements include the demonstration of high-speed IQ modulators, which are important building blocks in coherent optical communication systems. In this paper, we demonstrate silicon photonic QPSK modulator based on a metal-oxide-semiconductor (MOS) capacitor structure, address different modulator configuration structures and report our progress and research associated with highspeed advanced optical modulation in silicon photonics

  3. Performance of the CLAS12 Silicon Vertex Tracker modules

    SciTech Connect

    Antonioli, Mary Ann; Boiarinov, Serguie; Bonneau, Peter R.; Elouadrhiri, Latifa; Eng, Brian J.; Gotra, Yuri N.; Kurbatov, Evgeny O.; Leffel, Mindy A.; Mandal, Saptarshi; McMullen, Marc E.; Merkin, Mikhail M.; Raydo, Benjamin J.; Teachey, Robert W,; Tucker, Ross J.; Ungaro, Maurizio; Yegneswaran, Amrit S.; Ziegler, Veronique

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156{micro}m, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  4. Control Performance of Vehicle Abs Featuring ER Valve Pressure Modulator

    NASA Astrophysics Data System (ADS)

    Cho, M. S.; Choi, S. B.; Wereley, N. M.

    In this work, an electrically controllable anti-lock brake system (ABS) for passenger vehicle is developed by utilizing electrorheological (ER) fluid. A pressure modulator which consists of a cylindrical ER valve and the hydraulic booster is constructed in order to achieve sufficient brake pressure variation during ABS operation. The principal design parameters of the modulator are determined by considering ER properties as well as required braking pressure. After investigating pressure controllability of the modulator, a vehicle model which is integrated with the proposed pressure modulator is formulated to design yaw rate controller. A sliding mode controller is designed to obtain desired yaw rate, and the friction forces between roads and wheels are estimated via the estimator. Braking performances of the proposed ABS under various roads are evaluated through the hardware-in-the-loop-simulation (HILS) and the steering stability during braking operation is demonstrated by undertaking split-μ test.

  5. Performance of the CLAS12 Silicon Vertex Tracker modules

    NASA Astrophysics Data System (ADS)

    Antonioli, M. A.; Boiarinov, S.; Bonneau, P.; Elouadrhiri, L.; Eng, B.; Gotra, Y.; Kurbatov, E.; Leffel, M.; Mandal, S.; McMullen, M.; Merkin, M.; Raydo, B.; Teachey, W.; Tucker, R.; Ungaro, M.; Yegneswaran, A.; Ziegler, V.

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156 μm, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  6. Airbag Landing Impact Performance Optimization for the Orion Crew Module

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; McKinney, John; Corliss, James M.

    2008-01-01

    This report will discuss the use of advanced simulation techniques to optimize the performance of the proposed Orion Crew Module airbag landing system design. The Boeing Company and the National Aeronautic and Space Administration s Langley Research Center collaborated in the analysis of the proposed airbag landing system for the next generation space shuttle replacement, the Orion spacecraft. Using LS-DYNA to simulate the Crew Module landing impacts, two main objectives were established and achieved: the investigation of potential methods of optimizing the airbag performance in order to reduce rebound on the anti-bottoming bags, lower overall landing loads, and increase overall Crew Module stability; and the determination of the Crew Module stability and load boundaries using the optimized airbag design, based on the potential Crew Module landing pitch angles and ground slopes in both the center of gravity forward and aft configurations. This paper describes the optimization and stability and load boundary studies and presents a summary of the results obtained and key lessons learned from this analysis.

  7. Performance Study of optical Modulator based on electrooptic effect

    NASA Astrophysics Data System (ADS)

    Palodiya, V.; Raghuwanshi, S. K.

    2016-08-01

    In this paper, we have studied and derive performance parameter of highly integrated Lithium Niobate optical modulator. This is a chirp free modulator having low switching voltage and large bandwidth. For an external modulator in which travelling-wave electrodes length L imposed the modulating switching voltage, the product of Vπ and L is fixed for a given electro optic material Lithium Niobate. We investigate to achieve a low Vπ by both magnitude of the electro-optic coefficient for a wide variety of electro-optic materials. A Sellmeier equation for the extraordinary index of congruent lithium niobate is derived. For phase-matching, predictions are accmate for temperature between room temperature 250°C and wavelength ranging from 0.4 to 5µm. The Sellmeier equations predict more accmately refractive indices at long wavelengths. Theoretical result is confirmed by simulated results. We have analysed the various parameters such as switching voltage, device performance index, time constant, transmittance, cut-off frequency, 3-dB bandwidth, power absorption coefficient and transmission bit rate of Lithium Niobate optical Modulator based on electro -optic effect.

  8. Theoretical Approach to Predict the Performance of Thermoelectric Generator Modules

    NASA Astrophysics Data System (ADS)

    Elarusi, Abdulmunaem H.; Fagehi, Hassan; Lee, Hosung; Attar, Alaa

    2016-10-01

    The aim of this work was to examine the validity of the thermoelectric modules' performance predicted by formulating the effective thermoelectric material properties. The three maximum parameters (output power, current, and efficiency) are defined in terms of the average temperature of the thermoelectric generator (TEG). These three maximum parameters, which are either taken from commercial TEG modules or measurements for particular operating conditions, are used to define the effective material properties (Seebeck coefficient, thermal conductivity, and electrical resistivity). The commercial performance curves provided by the manufacturer were compared with the results obtained here by the effective material properties with the simple standard thermoelectric equations. It has been found that this technique predicts the performance of four commercial thermoelectric modules with fair to good accuracy. The characteristics of the TEGs were represented using the normalized charts constructed by formulating the parameters as a fraction of over the maximum parameters. The normalized charts would be universal for any given TEG module once the thermoelectric material is known.

  9. Outdoor performance of CIGS modules in different climates

    NASA Astrophysics Data System (ADS)

    Toivola, Kristopher; Robusto, Paul F.; Saproo, Ajay; Kessler, Bill

    2014-10-01

    Outdoor product reliability testing of MiaSolé Glass-Glass CIGS Modules in different external environments is an important aspect of determining the overall product durability and quality. The multi-year performance of MiaSolé modules in several different test regions will be presented. MiaSolé has implemented outdoor testing in Dry and Hot region (Phoenix, Arizona); Hot and Humid (Miami, Florida); Seasonally Cold with Snowfall (Medina, Ohio) and at MiaSolé Headquarters in Santa Clara, CA. MiaSolé used a second party to perform the outdoor testing in Arizona, Florida, and Ohio. We will review the details of the test site setup, installation, on-site implementation, data transfer and analysis methodology.

  10. The Light Microscopy Module Design and Performance Demonstrations

    NASA Technical Reports Server (NTRS)

    Motil, Susan M.; Snead, John H.; Griffin, DeVon W.; Hovenac, Edward A.

    2003-01-01

    The Light Microscopy Module (LMM) is a state-of-the-art space station payload to provide investigations in the fields of fluids, condensed matter physics, and biological sciences. The LMM hardware will reside inside the Fluids Integrated Rack (FIR), a multi-user facility class payload that will provide fundamental services for the LMM and future payloads. LMM and FIR will be launched in 2005 and both will reside in the Destiny module of the International Space Station (ISS). There are five experiments to be performed within the LMM. This paper will provide a description of the initial five experiments: the supporting FIR subsystems; LMM design; capabilities and key features; and a summary of performance demonstrations.

  11. Investigating effects of communications modulation technique on targeting performance

    NASA Astrophysics Data System (ADS)

    Blasch, Erik; Eusebio, Gerald; Huling, Edward

    2006-05-01

    One of the key challenges facing the global war on terrorism (GWOT) and urban operations is the increased need for rapid and diverse information from distributed sources. For users to get adequate information on target types and movements, they would need reliable data. In order to facilitate reliable computational intelligence, we seek to explore the communication modulation tradeoffs affecting information distribution and accumulation. In this analysis, we explore the modulation techniques of Orthogonal Frequency Division Multiplexing (OFDM), Direct Sequence Spread Spectrum (DSSS), and statistical time-division multiple access (TDMA) as a function of the bit error rate and jitter that affect targeting performance. In the analysis, we simulate a Link 16 with a simple bandpass frequency shift keying (PSK) technique using different Signal-to-Noise ratios. The communications transfer delay and accuracy tradeoffs are assessed as to the effects incurred in targeting performance.

  12. Independent learning modules enhance student performance and understanding of anatomy.

    PubMed

    Serrat, Maria A; Dom, Aaron M; Buchanan, James T; Williams, Alison R; Efaw, Morgan L; Richardson, Laura L

    2014-01-01

    Didactic lessons are only one part of the multimodal teaching strategies used in gross anatomy courses today. Increased emphasis is placed on providing more opportunities for students to develop lifelong learning and critical thinking skills during medical training. In a pilot program designed to promote more engaged and independent learning in anatomy, self-study modules were introduced to supplement human gross anatomy instruction at Joan C. Edwards School of Medicine at Marshall University. Modules use three-dimensional constructs to help students understand complex anatomical regions. Resources are self-contained in portable bins and are accessible at any time. Students use modules individually or in groups in a structured self-study format that augments material presented in lecture and laboratory. Pilot outcome data, measured by feedback surveys and examination performance statistics, suggest that the activity may be improving learning in gross anatomy. Positive feedback on both pre- and post-examination surveys showed that students felt the activity helped to increase their understanding of the topic. In concordance with student perception, average examination scores on module-related laboratory and lecture questions were higher in the two years of the pilot program compared with the year before its initiation. Modules can be fabricated on a modest budget using minimal resources, making implementation practical for smaller institutions. Upper level medical students assist in module design and upkeep, enabling continuous opportunities for vertical integration across the curriculum. This resource offers a feasible mechanism for enhancing independent and lifelong learning competencies, which could be a valuable complement to any gross anatomy curriculum.

  13. Temporal prediction errors modulate task-switching performance.

    PubMed

    Limongi, Roberto; Silva, Angélica M; Góngora-Costa, Begoña

    2015-01-01

    We have previously shown that temporal prediction errors (PEs, the differences between the expected and the actual stimulus' onset times) modulate the effective connectivity between the anterior cingulate cortex and the right anterior insular cortex (rAI), causing the activity of the rAI to decrease. The activity of the rAI is associated with efficient performance under uncertainty (e.g., changing a prepared behavior when a change demand is not expected), which leads to hypothesize that temporal PEs might disrupt behavior-change performance under uncertainty. This hypothesis has not been tested at a behavioral level. In this work, we evaluated this hypothesis within the context of task switching and concurrent temporal predictions. Our participants performed temporal predictions while observing one moving ball striking a stationary ball which bounced off with a variable temporal gap. Simultaneously, they performed a simple color comparison task. In some trials, a change signal made the participants change their behaviors. Performance accuracy decreased as a function of both the temporal PE and the delay. Explaining these results without appealing to ad hoc concepts such as "executive control" is a challenge for cognitive neuroscience. We provide a predictive coding explanation. We hypothesize that exteroceptive and proprioceptive minimization of PEs would converge in a fronto-basal ganglia network which would include the rAI. Both temporal gaps (or uncertainty) and temporal PEs would drive and modulate this network respectively. Whereas the temporal gaps would drive the activity of the rAI, the temporal PEs would modulate the endogenous excitatory connections of the fronto-striatal network. We conclude that in the context of perceptual uncertainty, the system is not able to minimize perceptual PE, causing the ongoing behavior to finalize and, in consequence, disrupting task switching. PMID:26379568

  14. Temporal prediction errors modulate task-switching performance

    PubMed Central

    Limongi, Roberto; Silva, Angélica M.; Góngora-Costa, Begoña

    2015-01-01

    We have previously shown that temporal prediction errors (PEs, the differences between the expected and the actual stimulus’ onset times) modulate the effective connectivity between the anterior cingulate cortex and the right anterior insular cortex (rAI), causing the activity of the rAI to decrease. The activity of the rAI is associated with efficient performance under uncertainty (e.g., changing a prepared behavior when a change demand is not expected), which leads to hypothesize that temporal PEs might disrupt behavior-change performance under uncertainty. This hypothesis has not been tested at a behavioral level. In this work, we evaluated this hypothesis within the context of task switching and concurrent temporal predictions. Our participants performed temporal predictions while observing one moving ball striking a stationary ball which bounced off with a variable temporal gap. Simultaneously, they performed a simple color comparison task. In some trials, a change signal made the participants change their behaviors. Performance accuracy decreased as a function of both the temporal PE and the delay. Explaining these results without appealing to ad hoc concepts such as “executive control” is a challenge for cognitive neuroscience. We provide a predictive coding explanation. We hypothesize that exteroceptive and proprioceptive minimization of PEs would converge in a fronto-basal ganglia network which would include the rAI. Both temporal gaps (or uncertainty) and temporal PEs would drive and modulate this network respectively. Whereas the temporal gaps would drive the activity of the rAI, the temporal PEs would modulate the endogenous excitatory connections of the fronto-striatal network. We conclude that in the context of perceptual uncertainty, the system is not able to minimize perceptual PE, causing the ongoing behavior to finalize and, in consequence, disrupting task switching. PMID:26379568

  15. Temporal prediction errors modulate task-switching performance.

    PubMed

    Limongi, Roberto; Silva, Angélica M; Góngora-Costa, Begoña

    2015-01-01

    We have previously shown that temporal prediction errors (PEs, the differences between the expected and the actual stimulus' onset times) modulate the effective connectivity between the anterior cingulate cortex and the right anterior insular cortex (rAI), causing the activity of the rAI to decrease. The activity of the rAI is associated with efficient performance under uncertainty (e.g., changing a prepared behavior when a change demand is not expected), which leads to hypothesize that temporal PEs might disrupt behavior-change performance under uncertainty. This hypothesis has not been tested at a behavioral level. In this work, we evaluated this hypothesis within the context of task switching and concurrent temporal predictions. Our participants performed temporal predictions while observing one moving ball striking a stationary ball which bounced off with a variable temporal gap. Simultaneously, they performed a simple color comparison task. In some trials, a change signal made the participants change their behaviors. Performance accuracy decreased as a function of both the temporal PE and the delay. Explaining these results without appealing to ad hoc concepts such as "executive control" is a challenge for cognitive neuroscience. We provide a predictive coding explanation. We hypothesize that exteroceptive and proprioceptive minimization of PEs would converge in a fronto-basal ganglia network which would include the rAI. Both temporal gaps (or uncertainty) and temporal PEs would drive and modulate this network respectively. Whereas the temporal gaps would drive the activity of the rAI, the temporal PEs would modulate the endogenous excitatory connections of the fronto-striatal network. We conclude that in the context of perceptual uncertainty, the system is not able to minimize perceptual PE, causing the ongoing behavior to finalize and, in consequence, disrupting task switching.

  16. Performance of single-photon-counting PILATUS detector modules

    PubMed Central

    Kraft, P.; Bergamaschi, A.; Broennimann, Ch.; Dinapoli, R.; Eikenberry, E. F.; Henrich, B.; Johnson, I.; Mozzanica, A.; Schlepütz, C. M.; Willmott, P. R.; Schmitt, B.

    2009-01-01

    PILATUS is a silicon hybrid pixel detector system, operating in single-photon-counting mode, that has been developed at the Paul Scherrer Institut for the needs of macromolecular crystallography at the Swiss Light Source (SLS). A calibrated PILATUS module has been characterized with monochromatic synchrotron radiation. The influence of charge sharing on the count rate and the overall energy resolution of the detector were investigated. The dead-time of the system was determined using the attenuated direct synchrotron beam. A single module detector was also tested in surface diffraction experiments at the SLS, whereby its performance regarding fluorescence suppression and saturation tolerance were evaluated, and have shown to greatly improve the sensitivity, reliability and speed of surface diffraction data acquisition. PMID:19395800

  17. Reciprocal Modulation of Cognitive and Emotional Aspects in Pianistic Performances

    PubMed Central

    Higuchi, Marcia K. Kodama; Fornari, José; Del Ben, Cristina M.; Graeff, Frederico G.; Leite, João Pereira

    2011-01-01

    Background High level piano performance requires complex integration of perceptual, motor, cognitive and emotive skills. Observations in psychology and neuroscience studies have suggested reciprocal inhibitory modulation of the cognition by emotion and emotion by cognition. However, it is still unclear how cognitive states may influence the pianistic performance. The aim of the present study is to verify the influence of cognitive and affective attention in the piano performances. Methods and Findings Nine pianists were instructed to play the same piece of music, firstly focusing only on cognitive aspects of musical structure (cognitive performances), and secondly, paying attention solely on affective aspects (affective performances). Audio files from pianistic performances were examined using a computational model that retrieves nine specific musical features (descriptors) – loudness, articulation, brightness, harmonic complexity, event detection, key clarity, mode detection, pulse clarity and repetition. In addition, the number of volunteers' errors in the recording sessions was counted. Comments from pianists about their thoughts during performances were also evaluated. The analyses of audio files throughout musical descriptors indicated that the affective performances have more: agogics, legatos, pianos phrasing, and less perception of event density when compared to the cognitive ones. Error analysis demonstrated that volunteers misplayed more left hand notes in the cognitive performances than in the affective ones. Volunteers also played more wrong notes in affective than in cognitive performances. These results correspond to the volunteers' comments that in the affective performances, the cognitive aspects of piano execution are inhibited, whereas in the cognitive performances, the expressiveness is inhibited. Conclusions Therefore, the present results indicate that attention to the emotional aspects of performance enhances expressiveness, but constrains

  18. A High Performance Delta-Sigma Modulator for Neurosensing.

    PubMed

    Xu, Jian; Zhao, Menglian; Wu, Xiaobo; Islam, Md Kafiul; Yang, Zhi

    2015-01-01

    Recorded neural data are frequently corrupted by large amplitude artifacts that are triggered by a variety of sources, such as subject movements, organ motions, electromagnetic interferences and discharges at the electrode surface. To prevent the system from saturating and the electronics from malfunctioning due to these large artifacts, a wide dynamic range for data acquisition is demanded, which is quite challenging to achieve and would require excessive circuit area and power for implementation. In this paper, we present a high performance Delta-Sigma modulator along with several design techniques and enabling blocks to reduce circuit area and power. The modulator was fabricated in a 0.18-µm CMOS process. Powered by a 1.0-V supply, the chip can achieve an 85-dB peak signal-to-noise-and-distortion ratio (SNDR) and an 87-dB dynamic range when integrated over a 10-kHz bandwidth. The total power consumption of the modulator is 13 µW, which corresponds to a figure-of-merit (FOM) of 45 fJ/conversion step. These competitive circuit specifications make this design a good candidate for building high precision neurosensors. PMID:26262623

  19. A High Performance Delta-Sigma Modulator for Neurosensing

    PubMed Central

    Xu, Jian; Zhao, Menglian; Wu, Xiaobo; Islam, Md. Kafiul; Yang, Zhi

    2015-01-01

    Recorded neural data are frequently corrupted by large amplitude artifacts that are triggered by a variety of sources, such as subject movements, organ motions, electromagnetic interferences and discharges at the electrode surface. To prevent the system from saturating and the electronics from malfunctioning due to these large artifacts, a wide dynamic range for data acquisition is demanded, which is quite challenging to achieve and would require excessive circuit area and power for implementation. In this paper, we present a high performance Delta-Sigma modulator along with several design techniques and enabling blocks to reduce circuit area and power. The modulator was fabricated in a 0.18-μm CMOS process. Powered by a 1.0-V supply, the chip can achieve an 85-dB peak signal-to-noise-and-distortion ratio (SNDR) and an 87-dB dynamic range when integrated over a 10-kHz bandwidth. The total power consumption of the modulator is 13 μW, which corresponds to a figure-of-merit (FOM) of 45 fJ/conversion step. These competitive circuit specifications make this design a good candidate for building high precision neurosensors. PMID:26262623

  20. Evaluation of misalignments within a concentrator photovoltaic module by the module optical analyzer: A case of study concerning temperature effects on the module performance

    NASA Astrophysics Data System (ADS)

    Herrero, Rebeca; Askins, Stephen; Antón, Ignacio; Sala, Gabriel

    2015-08-01

    Instituto de Energía Solar, Universidad Politécnica de Madrid (IES-UPM) has developed a method [referred to as the luminescence inverse (LI) method] and equipment [called module optical analyzer (MOA)] to fast measure the optical-angular properties of a CPV module without illumination system nor module movement. This paper presents how the MOA can investigate the optical performance of concentrator photovoltaic (CPV) modules optical-angular performance (in particular, misalignments between the optical components comprising the module) at different temperature conditions.

  1. Assess Student Performance: Skills. Second Edition. Module D-4 of Category D--Instructional Evaluation. Professional Teacher Education Module Series.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This module, one of a series of 127 performance-based teacher education learning packages focusing upon specific professional competencies of vocational education teachers, deals with assessing student performance of psychomotor skills. Included in the module are learning experiences that address the following topics: important considerations…

  2. Performance evaluation of partial response continuous phase modulation: Discriminator detection

    NASA Astrophysics Data System (ADS)

    Trachtman, Eyal

    1989-09-01

    The principles of continuous phase modulation (CPM) are reviewed and signalling schemes based on it are discussed. The discriminator detector is widely used to detect CPM signals on band limited channels; it is a non-coherent detector which is widely used in mobile communication applications in which fading makes coherent detection difficult; it is suitable for frequency hopping systems. The detector's inferior response to that of a coherent detector can be compensated by suitable design. The performance is compared of various receivers which use the discriminator detector, using an especially written computer simulation. Receiver schemes considered included: Full response signal with integrate and dump filter; Integrate and dump filter with differential symbol detection; zero forcing linear equalization with symbol detection; Decision feedback equalization (DFE); Maximum likelihood sequence estimation; and Tomlinson filter configuration. The Tomlinson filter configuration, which has not previously been used in a CPM communication system, was compared with the other systems with respect to performance and complexity. For all CPM and detection schemes there are optimum values of h, the modulation index and there is no benefit in increasing the value of h and, therefore the bandwidth, beyond this value. Results are presented for various signal schemes, which indicate that detectability performance can be improved and bandwidth reduced by using a partial response CPM. There is a tradeoff between detectability performance and bandwidth, as a function of the baseband pulse duration. It was found that quaternary signal schemes gave better detectability performance than binary schemes, for the same bit-rates. The simulation results indicated that the Tomlinson-DFE configuration was effective for the partial response M-ary CPM channel with discriminator detection; spectral efficiency was not seriously degraded by precoding using the Tomlinson filter, and there was no

  3. Noise performance of frequency modulation Kelvin force microscopy

    PubMed Central

    Deresmes, Dominique; Mélin, Thierry

    2014-01-01

    Summary Noise performance of a phase-locked loop (PLL) based frequency modulation Kelvin force microscope (FM-KFM) is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as “noise gain” from operational amplifier (OpAmp) design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values. PMID:24455457

  4. GPM Avionics Module Heat Pipes Design and Performance Test Results

    NASA Technical Reports Server (NTRS)

    Ottenstein, Laura; DeChristopher, Mike

    2011-01-01

    The Global Precipitation Measurement (GPM) mission is an international network of satellites that provide the next-generation global observations of rain and snow. The GPM core satellite carries an advanced radar / radiometer system to measure precipitation from space and serve as a reference standard to unify precipitation measurements from a constellation of research and operational satellites. Through improved measurements of precipitation globally, the GPM mission will help to advance our understanding of Earth's water and energy cycle, improve forecasting of extreme events that cause natural hazards and disasters, and extend current capabilities in using accurate and timely information of precipitation to directly benefit society. The avionics module on the core satellite contains a number of electronics boxes which are cooled by a network of aluminum/ammonia heat pipes and a honeycomb radiator which contains thirteen embedded aluminum/ammonia heat pipes. All heat pipes were individually tested by the vendor (Advanced Cooling Technologies, Inc.) prior to delivery. Following delivery to NASA, the flight avionics radiator and the flight spare transport heat pipes were mounted to flight-like test structure and a system level thermal vacuum test was performed. This test, which used simulators in place of all electronics boxes, was done to verify the operation of the thermal control system as a whole. This presentation will discuss the design of the avionics module heat pipes, and then discuss performance tests results for the individual heat pipes prior to delivery and for the system level thermal vacuum test. All heat pipes met their performance requirements. However, it was found that the power was too low in some instances to start all of the smaller radiator spreader heat pipes when they were tested in a reflux configuration (which is the nominal test configuration). Although this lowered the efficiency of the radiator somewhat, it did not impact the operating

  5. Auditory and motor imagery modulate learning in music performance.

    PubMed

    Brown, Rachel M; Palmer, Caroline

    2013-01-01

    Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians' encoding (during Learning, as they practiced novel melodies), and retrieval (during Recall of those melodies). Pianists learned melodies by listening without performing (auditory learning) or performing without sound (motor learning); following Learning, pianists performed the melodies from memory with auditory feedback (Recall). During either Learning (Experiment 1) or Recall (Experiment 2), pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced) and temporal regularity (variability of quarter-note interonset intervals) were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists' pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2). Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1): Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2): Higher auditory imagery skill predicted greater temporal regularity during Recall in the presence of

  6. Engineering sciences area and module performance and failure analysis area

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.; Runkle, L. D.

    1982-01-01

    Photovoltaic-array/power-conditioner interface studies are updated. An experiment conducted to evaluate different operating-point strategies, such as constant voltage and pilot cells, and to determine array energy losses when the array is operated off the maximum power points is described. Initial results over a test period of three and a half weeks showed a 2% energy loss when the array is operated at a fixed voltage. Degraded-array studies conducted at NE RES that used a range of simulated common types of degraded I-V curves are reviewed. The instrumentation installed at the JPL field-test site to obtain the irradiance data was described. Experiments using an optical filter to adjust the spectral irradiance of the large-area pulsed solar simulator (LAPSS) to AM1.5 are described. Residential-array research activity is reviewed. Voltage isolation test results are described. Experiments performed on one type of module to determine the relationship between leakage current and temperature are reviewed. An encapsulated-cell testing approach is explained. The test program, data reduction methods, and initial results of long-duration module testing are described.

  7. High performance TWT development for the microwave power module

    SciTech Connect

    Whaley, D.R.; Armstrong, C.M.; Groshart, G.; Stolz, R.

    1996-12-31

    Northrop Grumman`s ongoing development of microwave power modules (MPM) provides microwave power at various power levels, frequencies, and bandwidths for a variety of applications. Present day requirements for the vacuum power booster traveling wave tubes of the microwave power module are becoming increasingly more demanding, necessitating the need for further enhancement of tube performance. The MPM development program at Northrop Grumman is designed specifically to meet this need by construction and test of a series of new tubes aimed at verifying computation and reaching high efficiency design goals. Tubes under test incorporate several different helix designs, as well as varying electron gun and magnetic confinement configurations. Current efforts also include further development of state-of-the-art TWT modeling and computational methods at Northrop Grumman incorporating new, more accurate models into existing design tools and developing new tools to be used in all aspects of traveling wave tube design. Current status of the Northrop Grumman MPM TWT development program will be presented.

  8. Cost, performance, and reliability simulator for optical transceiver modules.

    PubMed

    Stirk, C W; Delen, N; Fedor, A; Ball, M; Hooker, R B; Wu, J S; Hareb, S; Ju, T H; Lee, Y C

    1998-09-10

    The program couple combines simulators for optical performance, mechanical reliability, and production cost under a graphical-user interface to design, simulate, and evaluate micro-optomechanical structures. The thermal simulator predicts the package temperature distribution on the basis of the materials and the geometry as well as on heat sources, sinks, and boundary conditions. The thermal distribution is input to the mechanical simulator, which calculates the stresses or strains and displacements caused by differential thermal expansion. The optical simulator predicts the impact on the optical efficiency and the cross talk of mechanical and optical parameter variations such as solder heights, misalignments, and wavelength distributions. The cost simulator represents the manufacturing process flow and calculates the final cost and the cost sensitivity on basis of the cost and the yield of each process step. By means of balancing detector and coupling yield, cosimulation from optical to cost domains determines the optimum detector size to produce the lowest-cost transceiver module. PMID:18286112

  9. Performance analysis of spread spectrum modulation in data hiding

    NASA Astrophysics Data System (ADS)

    Gang, Litao; Akansu, Ali N.; Ramkumar, Mahalingam

    2001-12-01

    Watermarking or steganography technology provides a possible solution in digital multimedia copyright protection and pirate tracking. Most of the current data hiding schemes are based on spread spectrum modulation. A small value watermark signal is embedded into the content signal in some watermark domain. The information bits can be extracted via correlation. The schemes are applied both in escrow and oblivious cases. This paper reveals, through analysis and simulation, that in oblivious applications where the original signal is not available, the commonly used correlation detection is not optimal. Its maximum likelihood detection is analyzed and a feasible suboptimal detector is derived. Its performance is explored and compared with the correlation detector. Subsequently a linear embedding scheme is proposed and studied. Experiments with image data hiding demonstrates its effectiveness in applications.

  10. Performance analysis of OFDM modulation on indoor broadband PLC channels

    NASA Astrophysics Data System (ADS)

    Antonio Cortés, José; Díez, Luis; Cañete, Francisco Javier; Sánchez-Martínez, Juan José; Entrambasaguas, José Tomás

    2011-12-01

    Indoor broadband power-line communications is a suitable technology for home networking applications. In this context, orthogonal frequency-division multiplexing (OFDM) is the most widespread modulation technique. It has recently been adopted by the ITU-T Recommendation G.9960 and is also used by most of the commercial systems, whose number of carriers has gone from about 100 to a few thousands in less than a decade. However, indoor power-line channels are frequency-selective and exhibit periodic time variations. Hence, increasing the number of carriers does not always improves the performance, since it reduces the distortion because of the frequency selectivity, but increases the one caused by the channel time variation. In addition, the long impulse response of power-line channels obliges to use an insufficient cyclic prefix. Increasing its value reduces the distortion, but also the symbol rate. Therefore, there are optimum values for both modulation parameters. This article evaluates the performance of an OFDM system as a function of the number of carriers and the cyclic prefix length, determining their most appropriate values for the indoor power-line scenario. This task must be accomplished by means of time-consuming simulations employing a linear time-varying filtering, since no consensus on a tractable statistical channel model has been reached yet. However, this study presents a simpler procedure in which the distortion because of the frequency selectivity is computed using a time-invariant channel response, and an analytical expression is derived for the one caused by the channel time variation.

  11. On the Performance of Multiple Pulse Multiple Delay UWB Modulation

    SciTech Connect

    Nekoogar, F; Dowla, F U

    2003-05-23

    Multiple access (MA) in UWB communication is an area of active research. In this paper we introduce and study the performance of a new MA scheme in the context of multiple transmitted-reference short duration (nsec) chirp pulses in the presence of additive white Gaussian noise (AWGN). The transmitted-reference (T-R) receiver is extended using multiple orthogonal pulses. The proposed UWB receiver samples the receiver autocorrelation function (ACF) at both zero- and non-zero lags, thus sampling and matching the shape of ACFs rather than just the shape of the received pulses. Sampling of non-zero ACF lags is a significant new approach. The scheme proposed in this paper is a step towards combining the multi-pulse approach and T-R modulation in a multiple access ultra wideband (MA-UWB) communications system. Improved bit error rate performance over a conventional zero-lag receiver (i.e. energy detection receiver) is demonstrated by simulation. Analytical expressions for the system BER are also derived and confirmed through simulations for the system.

  12. Development and performance of pulse-width-modulated static inverter and converter modules

    NASA Technical Reports Server (NTRS)

    Pittman, P. F.; Gourash, F.; Birchenough, A. G.; Pittman, P. F.; Ravas, R. J.; Hall, W. G.

    1971-01-01

    Pulse-width-modulated inverter and converter modules are being developed for modular aerospace electrical power systems. The modules, rate 2.5 kilowatts per module and 10-minute - 150-percent overload, operate from 56 volts dc. The converter module provides two output voltages: a nominal link voltage of 200 volts dc when used with the inverter, and 150 volts dc to a load bus when used separately. The inverter module output is 400-hertz, sinusoidal, three-phase, 120/208 volts. Tests of breadboard models with standard parts and integrated circuits show rated power efficiencies of 71.4 and 85.1 percent and voltage regulation of 5 and 3.1 percent for inverter and converter modules, respectively. Sine-wave output distortion is 0.74 percent.

  13. Performance Analysis of Different Modulation Formats in Optical Communication

    NASA Astrophysics Data System (ADS)

    Singh, Kulwinder; Singh, Maninder; Bhatia, Kamaljit Singh; Ryait, Hardeep Singh

    2016-06-01

    In this paper, we demonstrated the variation of different parameters with quadrature amplitude modulation (QAM) and differential phase shift key (DPSK) sequence generator, which generates modulated signals, in data transmission for communication and analysed that how the difference of these sequence generators effect its resonant frequency (RF) value, eye diagram and electrical constellation representation of the system.

  14. Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    ERIC Educational Resources Information Center

    Rains, Larry

    This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

  15. Comparative performance testing of photovoltaic modules in tropical climates of Indonesia

    NASA Astrophysics Data System (ADS)

    Rosyid, Oo Abdul

    2016-02-01

    Solar energy is one of the most significant types of the sustainable and renewable energy sources that have been used in Indonesia. Photovoltaic (PV) is known as the direct conversion of the sunlight to electricity energy with the used of solar cells. There are number of different types of solar PV modules, from an ever increasing range of manufacturers. Each of them claims that they are the best for one reason or another. This paper reports the study results of energy yield measurements of different PV module technologies performed at the outdoor testing facility of the Energy Technology Center (B2TE-BPPT) Kawasan Puspiptek Serpong-Indonesia from March 2014 through February 2015. The purposes of the study wereto evaluate and compare the performances of three different PV modules during a medium term outdoor exposure at the tropical climate of Indonesia. Normalized energy yields (Y), module efficiency (η), and performance ratio (PR) were calculated for each module, and the effect of module temperature and solar irradiance on these parameters was investigated. Monocrystalline PV module was better in terms of module efficiency and overall power production. Meanwhile micromorph silicon (uc-Si) showed the lowest module efficiency, but the more power production compared with polycrystalline PV module. Module efficiency and performance ratio showed a decreasing trend with increase of module temperature.

  16. Photovoltaic module performance and durability following long-term field exposure

    SciTech Connect

    Ellibee, D.E.; Hansen, B.R.; King, D.L.; Kratochvil, J.A.; Quintana, M.A.

    1998-09-08

    Our investigations of both new and field-aged photovoltaic modules have indicated that, in general, today's commercially available modules area highly reliable product. However, by using new test procedures, subtle failure mechanisms have also been identified that must be addressed in order to achieve 30-year module lifetimes. This paper summarizes diagnostic test procedures, results, and implications of in-depth investigations of the performance and durability characteristics of commercial modules after long-term field exposure. A collaborative effort with U.S. module manufacturers aimed at achieving 30-year module lifetimes is also described.

  17. Performances and failure of field-aged PV modules operating in Saharan region of Algeria

    NASA Astrophysics Data System (ADS)

    Sadok, M.; Benyoucef, B.; Othmani, M.; Mehdaoui, A.

    2016-07-01

    This article deals with behaviour of PV modules, of different technologies and manufacturers, exposed for long periods in Saharan region of Algeria. These modules are exposed in Adrar in the south-western part of Algeria. The study uses experimental I-V curves of PV modules for determining their performances. The datasheet information of modules will be useful in determination of degradation rates of the modules. Three types of modules have been tested: Photowatt (PWX 500), UDTS-50 and Isofoton (I-75 and I-100 serials). Results showed that Isofoton I-100 modules present the highest degradation rate while the lowest degradation rate was reached with I-75 serial. However, these rates tallies with other studies. The visual inspection of the modules has revealed various kinds of failures and defects responsible of performances drop (EVA browning, delamination, burn marks,…).

  18. Thermal and other tests of photovoltaic modules performed in natural sunlight

    NASA Technical Reports Server (NTRS)

    Stultz, J. W.

    1979-01-01

    The nominal operating cell temperature (NOCT), an effective way to characterize the thermal performance of a photovoltaic module in natural sunlight, is developed. NOCT measurements for more than twenty different modules are presented. Changes in NOCT reflect changes in module design, residential roof mounting, and dirt accumulation. Other test results show that electrical performance is improved by cooling modules with water and by use of a phase change wax. Electrical degradation resulting from the marriage of photovoltaic and solar water heating modules is demonstrated. Cost-effectiveness of each of these techniques is evaluated.

  19. Siemens solar CIS photovoltaic module and system performance at the National Renewable Energy Laboratory

    SciTech Connect

    Strand, T.; Kroposki, B.; Hansen, R.; Willett, D.

    1996-05-01

    This paper evaluates the individual module and array performance of Siemens Solar Industries copper indium diselenide (CIS) polycrystalline thin-film technology. This is accomplished by studying module and array performance over time. Preliminary temperature coefficients for maximum power, maximum-power voltage, maximum-power current, open-circuit voltage, short-circuit current, and fill factor are determined at both the module and array level. These coefficients are used to correct module/array performance to 25{degrees}C to evaluate stability. The authors show that CIS exhibits a strong inverse correlation between array power and back-of-module temperature. This is due mainly to the narrow bandgap of the CIS material, which results in a strong inverse correlation between voltage and temperature. They also show that the temperature-corrected module and array performance has been relatively stable over the evaluation interval ({approx}2 years).

  20. High Performance Power Module for Hall Effect Thrusters

    NASA Technical Reports Server (NTRS)

    Pinero, Luis R.; Peterson, Peter Y.; Bowers, Glen E.

    2002-01-01

    Previous efforts to develop power electronics for Hall thruster systems have targeted the 1 to 5 kW power range and an output voltage of approximately 300 V. New Hall thrusters are being developed for higher power, higher specific impulse, and multi-mode operation. These thrusters require up to 50 kW of power and a discharge voltage in excess of 600 V. Modular power supplies can process more power with higher efficiency at the expense of complexity. A 1 kW discharge power module was designed, built and integrated with a Hall thruster. The breadboard module has a power conversion efficiency in excess of 96 percent and weighs only 0.765 kg. This module will be used to develop a kW, multi-kW, and high voltage power processors.

  1. When do negative and positive emotions modulate working memory performance?

    PubMed Central

    Osaka, Mariko; Yaoi, Ken; Minamoto, Takehiro; Osaka, Naoyuki

    2013-01-01

    The present study investigated when emotion modulates working memory from the perspective of neural activation. Using fMRI, we measured brain activity during the encoding and retrieval phases of a reading span test (RST) that used emotional contexts. The emotional RST required participants to read sentences that elicited negative, neural or positive emotional states while they were memorizing target words from the sentences. Compared with the neutral RST, the negative RST activated the right amygdala during the reading phase. Significant activation was also found in the parahippocampal gyrus, albeit only after activation of the amygdala became comparable to that in the neutral RST. In contrast, the positive RST activated the substantia nigra during the reading phase relative to the neutral RST. These findings suggest that negative and positive emotions modulate working memory through distinctive neural circuits. We also discuss possible relationships between emotional modulation and working memory capacity. PMID:23459220

  2. The Light Microscopy Module Design and Performance Demonstrations

    NASA Astrophysics Data System (ADS)

    Motil, S. M.; Snead, J. H.; Griffin, D. W.; Hovenac, E. A.

    2002-01-01

    The Light Microscopy Module (LMM) is planned as a remotely controllable, automated, on-orbit microscope subrack facility, allowing flexible scheduling and control of fluids and biology experiments within the Fluids and Combustion Facility (FCF) Fluids Integrated Rack (FIR) on the International Space Station (ISS). The LMM recently completed the preliminary design phase, and is progressing toward engineering model development. This paper will provide a description of the LMM preliminary design, LMM planned capabilities and key features, a summary of demonstrations for each of the diagnostics, and future plans. In addition, a brief description of the initial four experiments will be provided. Key diagnostic capabilities for meeting science requirements include video microscopy to observe microscopic phenonema and dynamic interactions, interferometry to make thin film measurements with nanometer resolution, laser tweezers for particle manipulation, confocal microscopy to provide enhanced three-dimensional visualization of structures, and spectrophotometry to measure photonic properties of materials. The LMM also provides experiment sample containment for frangibles and fluids. Sample cell design allows investigators to perform experiments and observations on a variety of sample materials, including potential biological specimens. The LMM features high resolution video microscopy, brightfield, darkfield, phase contrast, differential interference contrast (DIC), and spectrophotometry in the visible 400 nm to 700 nm range. Laser tweezers is a custom-built system, shown to be capable of trapping up to a 5x5 array of colloidal particles. The LMM confocal system includes a commercial-off-the-shelf unit which utilizes a 532 nm frequency doubled Nd:Yag laser. This instrument has been demonstrated to provide images up to 80 microns deep in collodial samples. Spectrophotometry is a custom-built system that utilizes existing optical components within the microscope in addition

  3. Improvement of spatial light modulator optical input/output performance using microlens arrays.

    PubMed

    Chase, H; Handschy, M A; O'Callaghan, M J; Supon, F W

    1995-06-15

    Advanced spatial light modulators both detect incident light and modulate reflected light. Each pixel may contain multiple photodetectors, a modulator, control circuitry, and signal-processing circuitry. Because each detector and modulator occupies only a fraction of the area of a pixel the optical efficiency of these devices suffers. We have experimented with improving optical input/output performance by integrating a microlens array with a ferroelectric liquid-crystal VLSI spatial light modulator. We have studied the microlens VLSI spacing accuracy that must be achieved to yield minimum distortion of ref lected wave fronts and the best optical efficiency for Fourier-transform applications.

  4. Solar window collection and distribution module system. Final performance report

    SciTech Connect

    Not Available

    1985-01-01

    The construction and monitoring of a solar window collection and distribution system are presented. One complete window module was purchased and assembled, including: the glass, the window frames, sealants, grills, vents and a mechanical damper device. Monitoring of the system operation was limited to measuring inside air temperature, outside air temperature, and circulation temperatures through the window module systems, as well as the actual tinted glass surface temperature. The system has produced a reduction in glare, fading of furniture, and control of solar gains to a building structure.

  5. Thermal and other tests of photovoltaic modules performed in natural sunlight

    NASA Technical Reports Server (NTRS)

    Stultz, J. W.

    1978-01-01

    The bulk of the testing was the characterization of twenty-nine modules according to their nominal operating cell temperature (NOCT) and the effect on NOCT of changes in module design, various residential roof mounting configurations, and dirt accumulation. Other tests, often performed parallel with the NOCT measurements, evaluated the improvement in electrical performance by cooling the modules with water and by channeling the waste heat into a phase change material (wax). Electrical degradation resulting from the natural marriage of photovoltaic and solar water heating modules was also demonstrated. Cost effectiveness of each of these techniques are evaluated in light of the LSA cost goal of $0.50 per watt.

  6. Family Physicians’ Quality Interventions and Performance Improvement Through the ABFM Diabetes Performance in Practice Module

    PubMed Central

    Peterson, Lars E.; Blackburn, Brenna E.; Puffer, James C.; Phillips, Robert L.

    2014-01-01

    PURPOSE Practice performance assessment is the fourth requirement of Maintenance of Certification for Family Physicians (MC-FP). American Board of Family Medicine (ABFM) diplomates have many options for completing Part 4 requirements, including Web-based Performance in Practice Modules (PPMs) developed by the ABFM. Our objective was to describe the actions and outcomes of family physicians who completed the ABFM diabetes PPM. METHODS We undertook a descriptive study of all diabetes PPMs completed by physicians in the 50 United States and Washington, DC, from 2005 to October 2012. Successful completion required quality measure abstraction from 10 patient charts before and after a plan-do-study-act cycle improvement effort. We used descriptive statistics to assess physician demographics and quality outcomes. RESULTS Family physicians completed 7,924 diabetes qualitative improvement modules. Their mean age was 48.2 years, they had practiced a mean of 13.8 years, and three-fourths lived in urban areas (76.9%). Nearly one-half selected diabetic foot examination or eye examination as their quality improvement measure. Performance on all quality measures improved. Significant improvement was seen in rates of hemoglobin A1c control (<7.0%; 57.4% to 61.3%), blood pressure control (<130/90 mm Hg; 53.3% to 56.3%), foot examinations (68.0% to 85.8%); and retina examinations (55.5% to 71.1%). The most common interventions were standing orders (51.6%) and patient education (37.1%). CONCLUSIONS Family physicians participating in MC-FP implemented improvement projects and showed quality improvements in caring for patients with diabetes. Emphasis on quality of care by payers will increasingly require physicians to embrace quality measurement and improvement. PMID:24445099

  7. Performance improvement of PEFC modules with cell containing low amount of platinum

    SciTech Connect

    Miyake, Y.; Kadowaki, M.; Hamada, A.

    1996-12-31

    Cell components of the PEFC module were studied to improve the module performance. The cell performance in a high air utilization region was improved by selecting an air channel design of the separator in which high air flow speed was obtained. Optimization of Teflon{reg_sign} amount on the cathode backing carbon paper also contributed the cell performance. Modifications of the gas channel design and the backing carbon paper were carried out in a 200 cm{sup 2} x 20-cell module and 36-cell module. Dependence of air utilization on module performance was remarkably improved and power density of more than 0.3 W/cm{sup 2} was achieved in spite of the platinum amount in the cells was decreased to 1.1 Mg/cm{sup 2}.

  8. The influence of locomotor rehabilitation on module quality and post-stroke hemiparetic walking performance.

    PubMed

    Routson, Rebecca L; Clark, David J; Bowden, Mark G; Kautz, Steven A; Neptune, Richard R

    2013-07-01

    Recent studies have suggested the biomechanical subtasks of walking can be produced by a reduced set of co-excited muscles or modules. Individuals post-stroke often exhibit poor inter-muscular coordination characterized by poor timing and merging of modules that are normally independent in healthy individuals. However, whether locomotor therapy can influence module composition and timing and whether these improvements lead to improved walking performance is unclear. The goal of this study was to examine the influence of a locomotor rehabilitation therapy on module composition and timing and post-stroke hemiparetic walking performance. Twenty-seven post-stroke hemiparetic subjects participated in a 12-week locomotor intervention incorporating treadmill training with body weight support and manual trainers accompanied by training overground walking. Electromyography (EMG), kinematic and ground reaction force data were collected from subjects both pre- and post-therapy and from 19 age-matched healthy controls walking on an instrumented treadmill at their self-selected speed. Non-negative matrix factorization was used to identify the module composition and timing from the EMG data. Module timing and composition, and various measures of walking performance were compared pre- and post-therapy. In subjects with four modules pre- and post-therapy, locomotor training resulted in improved timing of the ankle plantarflexor module and a more extended paretic leg angle that allowed the subjects to walk faster and with more symmetrical propulsion. In addition, subjects with three modules pre-therapy increased their number of modules and improved walking performance post-therapy. Thus, locomotor training has the potential to influence module composition and timing, which can lead to improvements walking performance.

  9. Optimization of the Mechanical and Electrical Performance of a Thermoelectric Module

    NASA Astrophysics Data System (ADS)

    Sarhadi, Ali; Bjørk, Rasmus; Pryds, Nini

    2015-11-01

    Finite-element simulation of a thermoelectric (TE) module was conducted to optimize its geometrical dimensions in terms of mechanical reliability and performance. The TE module consisted of bismuth telluride n- and p-type legs. The geometrical dimensions of the module, i.e., leg length and leg cross-sectional area, were varied, and the corresponding maximum thermal stress, output power, and efficiency of the module obtained. An optimal design for the module was then suggested based on minimizing the thermal stresses and maximizing the performance, i.e., power and efficiency. The optimal dimensions at maximum von Mises stress of 75 MPa were leg length of 2 mm to 2.5 mm and leg width of 1.5 mm to 2 mm, resulting in efficiency of 7.2%. Finally, the influence of solders, i.e., solder material between the leg, the interconnector, and the top ceramic layer, on the induced thermal stresses and module performance was investigated. The results revealed that the transition from elastic to plastic deformation in the solder decreased the induced thermal stresses significantly. Moreover, beyond the elastic limit, the stress magnitude was highly dependent on the magnitude and mechanism of plastic deformation in the module. The present study provides a basis for a unique and new optimization scheme for TE modules in terms of endurance and performance.

  10. Working Smart. The Los Angeles Unified School District Workplace Literacy Project. Performance Modules. Communication Modules, Manual/Workbook. Computational Modules, Manual/Workbook.

    ERIC Educational Resources Information Center

    Los Angeles Unified School District, CA. Div. of Adult and Occupational Education.

    This document consists of performance, computational, and communication modules used by the Working Smart workplace literacy project, a project conducted for the hotel and food industry in the Los Angeles area by a public school district and several profit and nonprofit companies. Literacy instruction was merged with job requirements of the…

  11. Appendix model performance: Model documentation. Renewable Fuels Module of the National Energy Modelling System

    NASA Astrophysics Data System (ADS)

    1994-09-01

    Performance aspects of the Renewable Fuels Module (RFM) is discussed. The pattern of response of the RFM to typical changes in its major inputs from other NEMS modules is presented. The overall approach of this document, with the particular statistics presented, is designed to be comparable with similar analyses conducted for all of the modules of NEMS. While not always applicable, the overall approach has been to produce analyses and statistics that are as comparable as possible with model developer's reports for other NEMS modules. Those areas where the analysis is somewhat limited or constrained are discussed. Because the RFM consists of independent submodules, this appendix is broken down by submodule.

  12. PKCβII Modulation of Myocyte Contractile Performance

    PubMed Central

    Hwang, Hyosook; Robinson, Dustin A; Stevenson, Tamara K; Wu, Helen C; Kampert, Sarah E; Pagani, Francis D; Dyke, D. Brad; Martin, Jody L; Sadayappan, Sakthival; Day, Sharlene M; Westfall, Margaret V

    2012-01-01

    Significant up-regulation of the protein kinase CβII (PKCβII) develops during heart failure and yet divergent functional outcomes are reported in animal models. The goal here is to investigate PKCβII modulation of contractile function and gain insights into downstream targets in adult cardiac myocytes. Increased PKCβII protein expression and phosphorylation developed after gene transfer into adult myocytes while expression remained undetectable in controls. The PKCβII was distributed in a perinuclear pattern and this expression resulted in diminished rates and amplitude of shortening and re-lengthening compared to controls and myocytes expressing dominant negative PKCβII (PKCβDN). Similar decreases were observed in the Ca2+ transient and the Ca2+ decay rate slowed in response to caffeine in PKCβII-expressing myocytes. Parallel phosphorylation studies indicated PKCβII targets phosphatase activity to reduce phospholamban (PLB) phosphorylation at residue Thr17 (pThr17-PLB). The PKCβ inhibitor, LY379196 (LY) restored pThr17-PLB to control levels. In contrast, myofilament protein phosphorylation was enhanced by PKCβII expression, and individually, LY and the phosphatase inhibitor, calyculin A each failed to block this response. Further work showed PKCβII increased Ca2+- activated, calmodulin-dependent kinase IIδ (CaMKIIδ) expression and enhanced both CaMKIIδ and protein kinase D (PKD) phosphorylation. Phosphorylation of both signaling targets also was resistant to acute inhibition by LY. These later results provide evidence PKCβII modulates contractile function via intermediate downstream pathway(s) in cardiac myocytes. PMID:22587992

  13. Progress under the photovoltaic module and system performance and engineering project

    SciTech Connect

    Basso, T.S.

    1995-12-31

    The Photovoltaic (PV) Module and System Performance and Engineering Project ensures that state-of-the-art PV capabilities are available as resources for cooperative research and use by the US PV community. This paper covers recent progress and describes the engineering project`s equipment, facilities, and related technical expertise such as supporting measurement and analysis activities and developing PV standards and codes. The PV engineering project is responsible for conducting and verifying PV module, system, and solar radiometric research, engineering, testing, evaluation, and analysis. Technical results and solutions to issues are provided, including developing criteria for test and evaluation procedures, and verifying PV performance. Technical accomplishments are presented under the following primary areas. (1) PV Efficiency Measurements -- Standard Reporting Conditions activities provide comprehensive evaluations of PV cell and module performance, including standardized and traceable efficiency measurements and reference-cell calibration. (2) The PV Module and System Performance Testing and Reliability activities foster coordinated approaches among the interdisciplinary staff of PV scientists, engineers, and technicians. Through NREL`s Outdoor Test Facility and related laboratories, primary focus is on emerging PV module/system technology validation, module/array performance testing, module qualification testing and test-method development, PV module materials and component durability, and PV component diagnostics and failure analysis. (3) PV Radiometric Measurements and Evaluation activities directly support the characterizing, measuring, testing, designing, and understanding of the performance of PV cells, submodules, modules, and systems by providing scientific and engineering understanding of incident solar irradiance, and through the development of instruments and/or measurement methods.

  14. Σ-Δ modulator for a programmable gain, low-power, high-linearity automotive sensor interface

    NASA Astrophysics Data System (ADS)

    de la Rosa, Jose M.; Medeiro, Fernando; Perez-Verdu, Belen; del Rio, Rocio; Rodriguez-Vazquez, Angel

    2003-04-01

    Smart sensors play a critical role in modern automotive electronic systems, covering a wide range of data capturing functions and operating under adverse environmental conditions - temperature range of [-40¦C,175¦C]. In such sensors, the signal provided by transducers is composed of an offset voltage, which depends on the manufacturing process, and a low-frequency signal carrying the information. In practice, the offset voltage is subject to temperature variations, thus causing a shifting of the signal range to be measured. Therefore, the measuring circuit driving the sensor, normally formed by a low-noise preamplifier and an Analog-to-Digital Converter (ADC), must accommodate the complete range of possible offsets and real signals. In this scenario, the use of ADCs based on Sigma-Delta Modulators (SDMs) is convenient for several reasons. On the one hand, the noise-shaping performed by SDMs allows to achieve high resolution (16-17bits), in the band of interest (10-20kHz), with less power consumption than full Nyquist ADCs. On the other hand, the action of feedback renders SDMs very linear, and high-linearity is a must for automotive applications. Last but not least, the robustness of SDMs with respect to circuit imperfections make them suitable to include programmable gain without significant performance degradation. This feature allows to accommodate the complete range of possible offsets and information signals in a sensor interface with relaxed specifications for the preamplifier circuitry. This paper describes the design and implementation of a third-order cascade (2-1) SDM with programmable gain in a 0.35mm CMOS technology - the type of technology commonly employed for automotive applications (deep submicron is mostly employed for telecom). It is capable of handling signals up to 20-kHz bandwidth with 17-bit resolution. The programmable gain is implemented by a capacitor array whose unitary capacitors are connected or disconnected depending on the value of

  15. User's Manual for Data for Validating Models for PV Module Performance

    SciTech Connect

    Marion, W.; Anderberg, A.; Deline, C.; Glick, S.; Muller, M.; Perrin, G.; Rodriguez, J.; Rummel, S.; Terwilliger, K.; Silverman, T. J.

    2014-04-01

    This user's manual describes performance data measured for flat-plate photovoltaic (PV) modules installed in Cocoa, Florida, Eugene, Oregon, and Golden, Colorado. The data include PV module current-voltage curves and associated meteorological data for approximately one-year periods. These publicly available data are intended to facilitate the validation of existing models for predicting the performance of PV modules, and for the development of new and improved models. For comparing different modeling approaches, using these public data will provide transparency and more meaningful comparisons of the relative benefits.

  16. Performing music can induce greater modulation of emotion-related psychophysiological responses than listening to music.

    PubMed

    Nakahara, Hidehiro; Furuya, Shinichi; Masuko, Tsutomu; Francis, Peter R; Kinoshita, Hiroshi

    2011-09-01

    The present study investigated the differential effects of music-induced emotion on heart rate (HR) and its variability (HRV) while playing music on the piano and listening to a recording of the same piece of music. Sixteen pianists were monitored during tasks involving emotional piano performance, non-emotional piano performance, emotional perception, and non-emotional perception. It was found that emotional induction during both perception and performance modulated HR and HRV, and that such modulations were significantly greater during musical performance than during perception. The results confirmed that musical performance was far more effective in modulating emotion-related autonomic nerve activity than musical perception in musicians. The findings suggest the presence of a neural network of reward-emotion-associated autonomic nerve activity for musical performance that is independent of a neural network for musical perception.

  17. Performance of High Voltage Modules Under Abuse Operations

    NASA Technical Reports Server (NTRS)

    Jeevarajan, Judith A.; Darcy, Eric C.; Irlbeck, Bradley W.

    2005-01-01

    The Electric Auxiliary Power Unit (EAPU) or the Advanced Hydraulic Power System (AHPS) is a Shuttle Upgrade program. Of the two battery design approaches that were considered in support of this program, the current paper concentrates on the testing performed on the small-cell approach. Testing performed at both ComDev Space, Canada and at NASA-JSC is described in this paper. Testing included those under mission profile conditions and off-nominal abusive conditions.

  18. Modulation performance of semiconductor laser coupled with an ultra-short external cavity

    NASA Astrophysics Data System (ADS)

    Ahmed, Moustafa; Bakry, Ahmed

    2016-02-01

    We present modeling on the evaluation of the modulation performance of semiconductor laser coupled with an ultra-short external cavity in terms of the intensity modulation (IM) response, relative intensity noise (RIN), carrier to noise ratio (CNR), and frequency chirp. The modulation is characterized along the period-doubling (PD) route to chaos induced by optical feedback (OFB). We focus on the possibility of increasing the modulation bandwidth by improving the carrier-photon resonance (CPR) frequency or inducing resonant modulation due to photon-photon resonance (PPR). We show that along the route to chaos, OFB could increase the CPR frequency and improve the 3 dB-modulation bandwidth from 19 GHz to 28 GHz. When strong OFB keeps the continuous wave (CW) operation or induces periodic oscillation (PO), PPR becomes significant and reveals resonance modulation over mm-frequency passband exceeding 50 GHz. Both CNR and frequency chirp are also enhanced around the CPR and PPR frequencies. The highest CNR peak is obtained when modulating the CW or PO laser, whereas the maximum peak of chirp corresponds to non-modulated chaotic laser.

  19. Final Technical Report - Recovery Act: Organic Coatings as Encapsulants for Low Cost, High Performance PV Modules

    SciTech Connect

    Stuart Hellring; Jiping Shao; James Poole

    2011-12-05

    The objective of this project was to evaluate the feasibility of utilizing PPG's commercial organic coatings systems as efficient, modernized encapsulants for low cost, high performance, thin film photovoltaic modules. Our hypothesis was that the combination of an anticorrosive coating with a more traditional barrier topcoat would mitigate many electrochemical processes that are now responsible for the significant portion of photovoltaic (PV) failures, thereby nullifying the extremely high moisture barrier requirements of currently used encapsulation technology. Nine commercially available metal primer coatings and six commercially available top coatings were selected for screening. Twenty-one different primer/top coat combinations were evaluated. The primer coatings were shown to be the major contributor to corrosion inhibition, adhesion, and barrier properties. Two primer coatings and one top coating were downselected for testing on specially-fabricated test modules. The coated test modules passed initial current leakage and insulation testing. Damp Heat testing of control modules showed visible corrosion to the bus bar metal, whereas the coated modules showed none. One of the primer/top coat combinations retained solar power performance after Damp Heat testing despite showing some delamination at the EVA/solar cell interface. Thermal Cycling and Humidity Freeze testing resulted in only one test module retaining its power performance. Failure modes depended on the particular primer/top coating combination used. Overall, this study demonstrated that a relatively thin primer/top coating has the potential to replace the potting film and backsheet in crystalline silicon-based photovoltaic modules. Positive signals were received from commercially available coatings developed for applications having performance requirements different from those required for photovoltaic modules. It is likely that future work to redesign and customize these coatings would result in a

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  1. Internal performance predictions for Langley scramjet engine module

    NASA Technical Reports Server (NTRS)

    Pinckney, S. Z.

    1978-01-01

    A one dimensional theoretical method for the prediction of the internal performance of a scramjet engine is presented. The effects of changes in vehicle forebody flow parameters and characteristics on predicted thrust for the scramjet engine were evaluated using this method, and results are presented. A theoretical evaluation of the effects of changes in the scramjet engine's internal parameters is also presented. Theoretical internal performance predictions, in terms thrust coefficient and specific impulse, are provided for the scramjet engine for free stream Mach numbers of 5, 6, and 7 free stream dynamic pressure of 23,940 N/sq m forebody surface angles of 4.6 deg to 14.6 deg, and fuel equivalence ratio of 1.0.

  2. The SOUDAN 2 detector The operation and performance of the tracking calorimeter modules

    NASA Astrophysics Data System (ADS)

    Allison, W. W. M.; Alner, G. J.; Ambats, I.; Ayres, D. S.; Balka, L. J.; Barr, G. D.; Barrett, W. L.; Benjamin, D.; Bode, C.; Border, P. M.; Brooks, C. B.; Cobb, J. H.; Cockerill, D. J. A.; Coover, K.; Cotton, R. J.; Courant, H.; Dahlin, B. B.; DasGupta, U.; Dawson, J. W.; Demuth, D. M.; Edwards, V. W.; Ewen, B.; Fields, T. H.; Garcia-Garcia, C.; Gallagher, H. M.; Giles, R. H.; Giller, G. L.; Goodman, M. C.; Gray, R. N.; Heppelmann, S.; Hill, N.; Hoftiezer, J. H.; Jankowski, D. J.; Johns, K.; Joyce, T.; Kafka, T.; Kasahara, S. M. S.; Kirby-Gallagher, L. M.; Kochocki, J.; Leeson, W.; Litchfield, P. J.; Longley, N. P.; Lopez, F. V.; Lowe, M. J.; Mann, W. A.; Marshak, M. L.; May, E. N.; Maxam, D.; McMaster, L.; Milburn, R.; Miller, W. H.; Minor, C. P.; Mondal, N.; Mualem, L.; Napier, A.; Nelson, E. M.; Nickson, R.; Oliver, W.; Pearce, G. F.; Perkins, D. H.; Peterson, E. A.; Price, L. E.; Roback, D. M.; Rosen, D. B.; Ruddick, K.; Saitta, B.; Schmid, D. J.; Schlereth, J.; Schneps, J.; Schub, M. H.; Seidlein, R. V.; Shield, P. D.; Shupe, M. A.; Spear, S.; Stassinakis, A.; Sundaralingam, N.; Thomson, M. A.; Thron, J. L.; Vassiliev, V.; Villaume, G.; Wakely, S. P.; Wall, D.; Wallis, E. W. G.; Weems, L.; Werkema, S. J.; West, N.; Wielgosz, U.; Woods, C. A.; Yarker, S.

    1996-02-01

    SOUDAN 2 is a 960-ton tracking calorimeter which has been constructed to search for nucleon decay and other phenomena. The full detector consists of 224 calorimeter modules each weighing 4.3 tons. The modules consist of finely segmented iron instrumented with 1 m long drift tubes of 15 mm internal diameter. The tubes enable three spatial coordinates and {dE }/{dx } to be recorded for charged particles traversing the tubes. The spatial resolution is 0.38 cm in the x- y plane and 0.65 cm in the z, or drift, direction. The operation and performance of the modules are discussed.

  3. Performance characteristics of a thermal energy storage module - A transient PCM/forced convection conjugate analysis

    NASA Technical Reports Server (NTRS)

    Cao, Y.; Faghri, A.

    1991-01-01

    The performance of a thermal energy storage module is simulated numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid with low Prandtl numbers are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. The numerical results show that module geometry is crucial to the design of a space-based thermal energy storage system.

  4. Low Temperature Performance of High Power Density DC/DC Converter Modules

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    In this paper, two second-generation high power density DC/DC converter modules have been evaluated at low operating temperatures. The power rating of one converter (Module 1) was specified at 150 W with an input voltage range of 36 to 75 V and output voltage of 12 V. The other converter (Module 2) was specified at 100 W with the same input voltage range and an output voltage of 3.3 V. The converter modules were evaluated in terms of their performance as a function of operating temperature in the range of 25 to -140 C. The experimental procedures along with the experimental data obtained are presented and discussed in this paper.

  5. Evaluation of Temperature-Dependent Effective Material Properties and Performance of a Thermoelectric Module

    NASA Astrophysics Data System (ADS)

    Chien, Heng-Chieh; Chu, En-Ting; Hsieh, Huey-Lin; Huang, Jing-Yi; Wu, Sheng-Tsai; Dai, Ming-Ji; Liu, Chun-Kai; Yao, Da-Jeng

    2013-07-01

    We devised a novel method to evaluate the temperature-dependent effective properties of a thermoelectric module (TEM): Seebeck coefficient ( S m), internal electrical resistance ( R m), and thermal conductance ( K m). After calculation, the effective properties of the module are converted to the average material properties of a p- n thermoelectric pillar pair inside the module: Seebeck coefficient ( S TE), electrical resistivity ( ρ TE), and thermal conductivity ( k TE). For a commercial thermoelectric module (Altec 1091) chosen to verify the novel method, the measured S TE has a maximum value at bath temperature of 110°C; ρ TE shows a positive linear trend dependent on the bath temperature, and k TE increases slightly with increasing bath temperature. The results show the method to have satisfactory measurement performance in terms of practicability and reliability; the data for tests near 23°C agree with published values.

  6. Performance characterization of an internsity-modulated fiber optic displacement sensor

    SciTech Connect

    Moro, Erik Allan; Todd, Michael D; Puckett, Santhony D

    2010-09-30

    A testbed simulating an intensity-modulated fiber optic displacement sensor is experimentally characterized, and the implications regarding sensor design are discussed. Of interest are the intensity distribution of the transmitted optical signal and the relationships between sensor architecture and performance. Particularly, an intensity-modulated sensor's sensitivity, linearity, displacement range, and resolution are functions of the relative positioning of its transmitting and receiving fibers. In this paper, sensor architectures with various combinations of these performance metrics are discussed. A sensor capable of micrometer resolution is reported, and it is concluded that this work could lead to an improved methodology for sensor design.

  7. Performance Stabilization of CdTe PV Modules using Bias and Light

    SciTech Connect

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Kurtz, S. R.

    2014-07-01

    Reversible performance changes due to light exposure frustrate repeatable performance measurements on CdTe PV modules. It is common to use extended light-exposure to ensure that measurements are representative of outdoor performance. We quantify the extent to which such a light-exposed state depends on module temperature and consider bias in the dark to aid in stabilization. We evaluate the use of dark forward bias to bring about a performance state equivalent to that obtained with light exposure, and to maintain a light-exposed state prior to STC performance measurement. Our results indicate that the most promising method for measuring a light-exposed state is to use light exposure at controlled temperature followed by prompt STC measurement with a repeatable time interval between exposure and the STC measurement.

  8. Student Performance in a Pharmacotherapy Oncology Module Before and After Flipping the Classroom.

    PubMed

    Bossaer, John B; Panus, Peter; Stewart, David W; Hagemeier, Nick E; George, Joshua

    2016-03-25

    Objective. To determine if a flipped classroom improved student examination performance in a pharmacotherapy oncology module. Design. Third-year pharmacy students in 2012 experienced the oncology module as interactive lectures with optional case studies as supplemental homework. In 2013, students experienced the same content in a primarily flipped classroom. Students were instructed to watch vodcasts (video podcasts) before in-class case studies but were not held accountable (ie, quizzed) for preclass preparation. Examination questions were identical in both cohorts. Performance on examination questions was compared between the two cohorts using analysis of covariance (ANCOVA), with prior academic performance variables (grade point average [GPA]) as covariates. Assessment. The students who experienced the flipped classroom approach performed poorer on examination questions than the cohort who experienced interactive lecture, with previous GPA used as a covariate. Conclusion. A flipped classroom does not necessarily improve student performance. Further research is needed to determine optimal classroom flipping techniques. PMID:27073284

  9. Student Performance in a Pharmacotherapy Oncology Module Before and After Flipping the Classroom

    PubMed Central

    Panus, Peter; Stewart, David W.; Hagemeier, Nick E; George, Joshua

    2016-01-01

    Objective. To determine if a flipped classroom improved student examination performance in a pharmacotherapy oncology module. Design. Third-year pharmacy students in 2012 experienced the oncology module as interactive lectures with optional case studies as supplemental homework. In 2013, students experienced the same content in a primarily flipped classroom. Students were instructed to watch vodcasts (video podcasts) before in-class case studies but were not held accountable (ie, quizzed) for preclass preparation. Examination questions were identical in both cohorts. Performance on examination questions was compared between the two cohorts using analysis of covariance (ANCOVA), with prior academic performance variables (grade point average [GPA]) as covariates. Assessment. The students who experienced the flipped classroom approach performed poorer on examination questions than the cohort who experienced interactive lecture, with previous GPA used as a covariate. Conclusion. A flipped classroom does not necessarily improve student performance. Further research is needed to determine optimal classroom flipping techniques. PMID:27073284

  10. Student Performance in a Pharmacotherapy Oncology Module Before and After Flipping the Classroom.

    PubMed

    Bossaer, John B; Panus, Peter; Stewart, David W; Hagemeier, Nick E; George, Joshua

    2016-03-25

    Objective. To determine if a flipped classroom improved student examination performance in a pharmacotherapy oncology module. Design. Third-year pharmacy students in 2012 experienced the oncology module as interactive lectures with optional case studies as supplemental homework. In 2013, students experienced the same content in a primarily flipped classroom. Students were instructed to watch vodcasts (video podcasts) before in-class case studies but were not held accountable (ie, quizzed) for preclass preparation. Examination questions were identical in both cohorts. Performance on examination questions was compared between the two cohorts using analysis of covariance (ANCOVA), with prior academic performance variables (grade point average [GPA]) as covariates. Assessment. The students who experienced the flipped classroom approach performed poorer on examination questions than the cohort who experienced interactive lecture, with previous GPA used as a covariate. Conclusion. A flipped classroom does not necessarily improve student performance. Further research is needed to determine optimal classroom flipping techniques.

  11. Performance of First-Year Health Sciences Students in a Large, Diverse, Multidisciplinary, First-Semester, Physiology Service Module

    ERIC Educational Resources Information Center

    Tufts, Mark; Higgins-Opitz, Susan B.

    2014-01-01

    Health Science students at the University of KwaZulu-Natal perform better in their professional modules compared with their physiology modules. The pass rates of physiology service modules have steadily declined over the years. While a system is in place to identify "at-risk" students, it is only activated after the first semester. As a…

  12. Resource Person's Guide...to Using Performance-Based Teacher Education Materials. Second Edition. Professional Teacher Education Module Series.

    ERIC Educational Resources Information Center

    American Association for Vocational Instructional Materials, Athens, GA.

    This document is the second edition of a guide that is part of a series of performance-based teacher education (PBTE) modules and is intended to help those serving as resource persons in vocational teacher education programs designed around the modules and those serving in that capacity where the modules are used for competency-based staff…

  13. Performing Titration Analyses for Water Quality. Module 17. Vocational Education Training in Environmental Health Sciences.

    ERIC Educational Resources Information Center

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on performing titration analysis for water quality. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming each part of…

  14. Performance Characterization and Remedy of Experimental CuInGaSe2 Mini-Modules: Preprint

    SciTech Connect

    Pern, F. J.; Yan, F.; Mansfield, L.; Glynn, S.; Rekow, M.; Murion, R.

    2011-07-01

    We employed current-voltage (I-V), quantum efficiency (QE), photoluminescence (PL), electroluminescence (EL), lock-in thermography (LIT), and (electrochemical) impedance spectroscopy (ECIS) to complementarily characterize the performance and remedy for two pairs of experimental CuInGaSe2 (CIGS) mini-modules. One pair had the three scribe-lines (P1/P2/P3) done by a single pulse-programmable laser, and the other had the P2/P3 lines by mechanical scribe. Localized QE measurements for each cell strip on all four mini-modules showed non-uniform distributions that correlated well with the presence of performance-degrading strips or spots revealed by PL, EL, and LIT imaging. Performance of the all-laser-scribed mini-modules improved significantly by adding a thicker Al-doped ZnO layer and reworking the P3 line. The efficiency on one of the all-laser-scribed mini-modules increased notably from 7.80% to 8.56% after the performance-degrading spots on the side regions along the cell array were isolated by manual scribes.

  15. Performing Analyses for Waterborne Bacteria. Module 13. Vocational Education Training in Environmental Health Sciences.

    ERIC Educational Resources Information Center

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on performing analyses for waterborne bacteria. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming, sterilizing and…

  16. Effect of modulation format and jamming spectrum on performance of direct sequence spread spectrum systems

    NASA Technical Reports Server (NTRS)

    Levitt, B. K.

    1980-01-01

    The processing gain of a direct sequence spread spectrum system is approximately the ratio of the spreading code chip rate to the data rate. This paper provides a more accurate understanding of the performance of such systems as a function of the modulation scheme and jammer characteristics.

  17. Enhanced performance of graphene-based electro-absorption waveguide modulators by engineered optical modes

    NASA Astrophysics Data System (ADS)

    Gosciniak, J.; Tan, D. T. H.; Corbett, B.

    2015-06-01

    Electro-absorption modulators based on electrically contacted double-layer graphene optimally incorporated in plasmonic and photonic waveguide configurations were simulated and analyzed in terms of the device performance at telecom wavelengths. It is shown that increasing the mode electric field strength on the graphene layers enhances absorption of graphene and, in consequence, improves the electro-optic performances. The ratio of the change in extinction ratio and the waveguide loss (Δα/α) is used as a figure of merit. A plasmonic waveguide configuration with a silicon ridge has a simulated 3 dB modulation depth for a device length of ~140 nm and Δα/α ~ 20. The calculated energy consumption per bit is as low as ~240 aJ bit-1 and ~1.8 aJ bit-1 for plasmonic modulators with polymer and silicon ridge waveguides respectively. Much higher figures of merit were obtained for modulators based on photonic waveguides with Δα/α exceeding 220 for a waveguide with a TM-supported mode. This comes at the cost of the modulator length, which increases to over 500 nm, and the calculated energy per bit of 1.93 fJ bit-1 for polymer and ~10.3 aJ bit-1 for silicon waveguides. The photonic waveguides were designed to support both TM and TE modes. The TE mode requires a much longer modulation length of ~10 µm to achieve a 3 dB modulation depth and shows a lower figure of merit of ~12 compared to the TM mode, but has a low energy per bit of ~44.0 aJ bit-1. The TE mode is in the OFF state at low applied voltage.

  18. Relationships between baroreceptor cardiac reflex sensitivity and cognitive performance: modulations by gender and blood pressure.

    PubMed

    Paso, Gustavo A Reyes Del; Mata, José Luis; Martín-Vázquez, María

    2012-01-01

    This study aimed at replicating and extending previous results on the association between baroreceptor reflex sensitivity (BRS) and cognitive performance. Thirty men and 31 women performed an arithmetic task. After adjusting for numerical aptitude and effort, no predictors of performance were found in men. In women, the relationships between BRS and parameters related to correct responses were modulated by blood pressure (BP). BRS was inversely associated with these parameters for participants with BP>1 SD above the mean, whereas the associations were positive in participants with BP<1 SD below the mean. Also for women, BRS was positively associated with number of errors during the task. These results suggest that the relation between BRS and performance varies as a function of the type of cognitive processes assessed and that the central nervous system effects of the baroreceptors on cognitive functioning are modulated by gender and BP.

  19. The International Space Station's Multi-Purpose Logistics Module, Thermal Performance of the First Five Flights

    NASA Technical Reports Server (NTRS)

    Holladay, Jon; Cho, Frank

    2003-01-01

    The Multi-Purpose Logistics Module is the primary carrier for transport of pressurized payload to the International Space Station. Performing five missions within a thirteen month span provided a unique opportunity to gather a great deal of information toward understanding and verifying the orbital performance of the vehicle. This paper will provide a brief overview of the hardware history and design capabilities followed by a summary of the missions flown, resource requirements and possibilities for the future.

  20. Performance testing and module monitoring at the EC Necessary steps to develop cost-effective PV modules

    NASA Astrophysics Data System (ADS)

    Krebs, K.

    Testing programs carried out by the European Communities to establish testing techniques and standards for verifying the reliability and integrity of solar cells intended for the marketplace are described. The efforts are being expended to assure quality control and certification for photovoltaic (PV) products manufactured in any of the member nations. The failure rate for PV modules was lowered to 0.5 pct/year by 1981, and single cell failures are projected to be lowered to 0.00001/yr, connectors to 0.001/yr, and batteries to 0.01/yr. Day/night thermal cycling causes the most dominant type of failures, i.e., cracked cells and interconnect defects. Tests have been standardized for inspection, verification, performance, mechanical loading, hail impact, damp heat, high temperature long exposure, hot-spot heating, thermal cycling, and humidity-freezing tolerance.

  1. Energy performance of semi-transparent PV modules for applications in buildings

    NASA Astrophysics Data System (ADS)

    Fung, Yu Yan

    Owing to the increasing awareness on energy conservation and environmental protection, building-integrated photovoltaic (BIPV) has been developed rapidly in the past decade. A number of research studies have been conducted on the energy performance of BIPV systems. However, most of the previous studies focused on the systems that incorporated with opaque type PV modules, little attention has been devoted to semi-transparent type PV modules, which have been commonly integrated in modern architectures. This thesis aims at evaluating the energy performance of the semi-transparent BIPV modules, including heat gains to the indoor environment, power generation from the PV modules and daylight utilization. Solar radiation intensity on PV module's surfaces is an essential parameter for assessing energy performance of the PV modules. Different slope solar radiation models are analyzed and compared. The model that best suits Hong Kong situations is selected for the further development of the energy performance of the BIPV modules. The optimum orientation and tilted angle are determined in the analysis. In addition to the solar radiation models, a detailed investigation on the heat gain through the semi-transparent BIPV modules is carried out in this study. A one-dimensional transient heat transfer model, the SPVHG model, for evaluating the thermal performance of the semi-transparent BIPV modules is developed. The SPVHG model considers in detail the energy that is transmitted, absorbed and reflected in each element of the BIPV modules such as solar cells and glass layers. A computer program of the model is written accordingly. By applying the SPVHG model, the heat gain through the semi-transparent BIPV module of any thickness can be determined for any solar irradiance level. The annual performance can also be assessed by inputting annual weather data to the model. In order to verify the SPVHG model, laboratory tests have been carried out on semi-transparent BIPV modules. A

  2. Commercialization issues and funding opportunities for high-performance optoelectronic computing modules

    NASA Astrophysics Data System (ADS)

    Hessenbruch, John M.; Guilfoyle, Peter S.

    1997-01-01

    Low power, optoelectronic integrated circuits are being developed for high speed switching and data processing applications. These high performance optoelectronic computing modules consist of three primary components: vertical cavity surface emitting lasers, diffractive optical interconnect elements, and detector/amplifier/laser driver arrays. Following the design and fabrication of an HPOC module prototype, selected commercial funding sources will be evaluated to support a product development stage. These include the formation of a strategic alliance with one or more microprocessor or telecommunications vendors, and/or equity investment from one or more venture capital firms.

  3. Performance of staggered quadrature modulations over nonlinear satellite channels with uplink noise and intersymbol interference

    NASA Technical Reports Server (NTRS)

    Simon, M. K.; Divsalar, D.; Omura, J. K.

    1982-01-01

    In this paper, the performance of staggered quadrature modulations over nonlinear satellite channels is analyzed. The effects of uplink noise and intersymbol interference caused by transmitter filtering are included. The approach taken employs computational techniques based on moments of the interference. The expressions for the system bit error rate are derived for a general transponder model characterized by AM-AM and AM-PM conversion characteristics. Specific numerical results are presented for a hard-limited satellite repeater using staggered quadrature overlapped raised cosine (SQORC) and minimum-shift-keying (MSK) modulations.

  4. Energy performance of semi-transparent PV modules for applications in buildings

    NASA Astrophysics Data System (ADS)

    Fung, Yu Yan

    Owing to the increasing awareness on energy conservation and environmental protection, building-integrated photovoltaic (BIPV) has been developed rapidly in the past decade. A number of research studies have been conducted on the energy performance of BIPV systems. However, most of the previous studies focused on the systems that incorporated with opaque type PV modules, little attention has been devoted to semi-transparent type PV modules, which have been commonly integrated in modern architectures. This thesis aims at evaluating the energy performance of the semi-transparent BIPV modules, including heat gains to the indoor environment, power generation from the PV modules and daylight utilization. Solar radiation intensity on PV module's surfaces is an essential parameter for assessing energy performance of the PV modules. Different slope solar radiation models are analyzed and compared. The model that best suits Hong Kong situations is selected for the further development of the energy performance of the BIPV modules. The optimum orientation and tilted angle are determined in the analysis. In addition to the solar radiation models, a detailed investigation on the heat gain through the semi-transparent BIPV modules is carried out in this study. A one-dimensional transient heat transfer model, the SPVHG model, for evaluating the thermal performance of the semi-transparent BIPV modules is developed. The SPVHG model considers in detail the energy that is transmitted, absorbed and reflected in each element of the BIPV modules such as solar cells and glass layers. A computer program of the model is written accordingly. By applying the SPVHG model, the heat gain through the semi-transparent BIPV module of any thickness can be determined for any solar irradiance level. The annual performance can also be assessed by inputting annual weather data to the model. In order to verify the SPVHG model, laboratory tests have been carried out on semi-transparent BIPV modules. A

  5. Standardization of the energy performance of photovoltaic modules in real operating conditions

    NASA Astrophysics Data System (ADS)

    Viganó, Davide; Kenny, Robert P.; Müllejans, Harald; Alimonti, Gianluca

    2014-12-01

    The performance of a PV module at STC [1] is a useful indicator for comparing the peak performance of different module types, but on its own is not sufficient to accurately predict how much energy a module will deliver in the field when subjected to a wide range of real operating conditions [2]. An Energy Rating approach has to be preferred for that aim. It is currently under development the standard series IEC 61853 on Energy Rating, for which only part 1 [3] has been issued. It describes methods to characterize the module performance as a function of irradiance and temperature. The reproducibility of the power matrix measurements obtained by the three different methods specified in the standard, namely: under natural sunlight using a tracking system; under natural sunlight without tracker; and a large area pulsed solar simulator of Class AAA were evaluated and discussed [4,5]. The work here presented is focused on the second method listed above, which explores the real working conditions for a PV device and therefore it represents the situation where Energy Rating procedures are expected to give the largest deviations from the STC predictions. The system for continuous monitoring of module performances, already implemented at ESTI, has been recently replaced with a new system having a number of improvements described in the following. The two system results have been compared showing a discrete compatibility. The two power matrices are then merged together using a weighted average and compared to those acquired with the other two remaining "ideal" systems. An interesting tendency seems to come up from this comparison, making the power rating under real operating conditions an essential procedure for energy rating purposes.

  6. Module to perform multiplication, division, and square root in systolic arrays for matrix computations

    SciTech Connect

    Ercegovac, M.D.; Lang, T. )

    1991-03-01

    This paper presents a module that performs multiplication, division, and square root. The implementation is compact because most of the components are shared by all three operations, the complexity being similar to a radix-2 divider. All three operations have the same execution time: one bit of the result is produced per cycle, beginning with the most significant bit. The cycle time is kept small by using redundant addition (carry-save or signed-digit) and a result-digit selection based on a low-precision estimate of the partial remainder. These properties make the module suitable for systolic arrays for matrix computations. Moreover, the communication between these modules in systolic arrays is bit-serial, yet the delay is the same as that for systems with bit-parallel communication.

  7. Analysis and measurement of the external modulation of modelocked laser diodes (Relative noise performance)

    NASA Astrophysics Data System (ADS)

    Lam, B. C.; Kellner, A. L.; Campion, D. C.; Costa, J. M.; Yu, P. K. L.

    1991-02-01

    The measurement of the relative intensity noise (RIN) of a ridge waveguide laser and a distributed feedback laser under CW, external cavity, direct modulation, and modelocking conditions is presented. The purpose is to determine the relative noise performance of modelocked laser diodes. The results indicate that the RIN of modelocked lasers are comparable to CW lasers but lower than both external cavity lasers (optimized for modelocking but without the applied RF) and directly modulated lasers; the difference can be as much as 5 optical dB. The microwave carriers produced optically by the direct modulation and modelocking of laser diodes are also compared. The comparison determines that modelocked lasers produce less noisy and more RF power efficient microwave carriers. However, no difference in microwave linewidth is detected within the limit of the resolution bandwidth of the detection system.

  8. Performance Simulation of a Flat-Plate Thermoelectric Module Consisting of Square Truncated Pyramid Elements

    NASA Astrophysics Data System (ADS)

    Oki, Sae; Suzuki, Ryosuke O.

    2016-09-01

    The performance of a flat-plate thermoelectric (TE) module consisting of square truncated pyramid elements is simulated using commercial software and original TE programs. Assuming that the temperatures of both the hot and cold surfaces are constant, the performance can be varied by changing the element shape and element alignment pattern. When the angle between the edge and the base is 85° and the small square surfaces of all n-type element faces are connected to the low-temperature surface, the efficiency becomes the largest among all the 17 examined shapes and patterns. By changing the shape to match the temperature distribution, the performance of the TE module is maximized.

  9. Error rate performance of pulse position modulation schemes for indoor wireless optical communication

    NASA Astrophysics Data System (ADS)

    Azzam, Nazmy; Aly, Moustafa H.; AboulSeoud, A. K.

    2009-06-01

    Error rate performance of pulse position modulation (PPM) schemes for indoor wireless optical communication (WOC) applications is investigated. These schemes include traditional PPM and multiple PPM (MPPM). Study is unique in presenting and evaluating symbol error behaviour under wide range of design parameters such symbol length (L), number of chips per symbol (n), number of chips forms optical pulse (w). Effect of signal to noise ratio levels and operating bitrates on symbol error performance is also discussed. A comparison between studying modulation schemes is done. Relation with IrDA and IEEE 802.11 indoor WOC standardization is also investigated. Results indicate that PPM achieve great symbol error performance at reasonable signal to noise ratio and high bitrates with large symbol length.

  10. Performance of Multiple Pulse Multiple Delay Modulated UWB Signals in a Multiple Access Indoor Wireless Channel

    SciTech Connect

    Nekoogar, F

    2003-06-12

    In this paper, the performance of a two user UWB multiple access (UWB-MA) system based on multiple-pulse multiple-delay (MPMD) modulation scheme in an indoor wireless channel is evaluated by computer simulations. The indoor multipath propagation channel model used in this study is based on the modified statistical Saleh-Valenzuela model proposed by Foerester and Li from Intel. The simulation results indicate that the multipath performance of MPMD modulated signals in a multiple access system outperforms the nonmultipath case as the number of autocorrelation function (ACF) sampling points increases for each user. This is an unusual but important result, since MPMD receiver exploits multipath phenomenon in indoor wireless channels to increase the BER performance, hence the transmission rate in a UWB-MA system.

  11. RF Transceivers for Wireless Body Area Network Controllers

    NASA Astrophysics Data System (ADS)

    Eshra, Islam; Allam, Mootaz; Sayed, Alhassan; Benabid, Sorore; Aboushady, Hassan

    2015-11-01

    This paper focuses on the system and circuit level consideration of radio frequency front-end transceivers dedicated to WBAN controllers. We show how highly digitized transceivers employing sigma-delta modulators can achieve the frequency agility required by WBAN controllers. The paper compares the performance and highlights the pros and cons of I/Q transmitters and polar transmitters. For the receiver, different sigma-delta based RF receiver architectures are presented. These architectures are compared with more conventional architectures in terms of their suitability to WBAN controllers.

  12. Indium-Tin-Oxide for High-performance Electro-optic Modulation

    NASA Astrophysics Data System (ADS)

    Ma, Zhizhen; Li, Zhuoran; Liu, Ke; Ye, Chenran; Sorger, Volker J.

    2015-06-01

    Advances in opto-electronics are often led by discovery and development of materials featuring unique properties. Recently, the material class of transparent conductive oxides (TCO) has attracted attention for active photonic devices on-chip. In particular, indium tin oxide (ITO) is found to have refractive index changes on the order of unity. This property makes it possible to achieve electrooptic modulation of sub-wavelength device scales, when thin ITO films are interfaced with optical light confinement techniques such as found in plasmonics; optical modes are compressed to nanometer scale to create strong light-matter interactions. Here we review efforts towards utilizing this novel material for high performance and ultra-compact modulation. While high performance metrics are achieved experimentally, there are open questions pertaining to the permittivity modulation mechanism of ITO. Finally, we review a variety of optical and electrical properties of ITO for different processing conditions, and show that ITO-based plasmonic electro-optic modulators have the potential to significantly outperform diffractionlimited devices.

  13. Is Baseline Cardiac Autonomic Modulation Related to Performance and Physiological Responses Following a Supramaximal Judo Test?

    PubMed Central

    Blasco-Lafarga, Cristina; Martínez-Navarro, Ignacio; Mateo-March, Manuel

    2013-01-01

    Little research exists concerning Heart Rate (HR) Variability (HRV) following supramaximal efforts focused on upper-body explosive strength-endurance. Since they may be very demanding, it seems of interest to analyse the relationship among performance, lactate and HR dynamics (i.e. HR, HRV and complexity) following them; as well as to know how baseline cardiac autonomic modulation mediates these relationships. The present study aimed to analyse associations between baseline and post-exercise HR dynamics following a supramaximal Judo test, and their relationship with lactate, in a sample of 22 highly-trained male judoists (20.70±4.56 years). A large association between the increase in HR from resting to exercise condition and performance suggests that individuals exerted a greater sympathetic response to achieve a better performance (Rating of Perceived Exertion: 20; post-exercise peak lactate: 11.57±2.24 mmol/L; 95.76±4.13 % of age-predicted HRmax). Athletes with higher vagal modulation and lower sympathetic modulation at rest achieved both a significant larger ∆HR and a faster post-exercise lactate removal. A enhanced resting parasympathetic modulation might be therefore related to a further usage of autonomic resources and a better immediate metabolic recovery during supramaximal exertions. Furthermore, analyses of variance displayed a persistent increase in α1 and a decrease in lnRMSSD along the 15 min of recovery, which are indicative of a diminished vagal modulation together with a sympathovagal balance leaning to sympathetic domination. Eventually, time-domain indices (lnRMSSD) showed no lactate correlations, while nonlinear indices (α1 and lnSaEn) appeared to be moderate to strongly correlated with it, thus pointing to shared mechanisms between neuroautonomic and metabolic regulation. PMID:24205273

  14. Performance evaluation of multilevel modulation formats using partial response for capacity upgrade in access network with limited electronic bandwidth

    NASA Astrophysics Data System (ADS)

    Madsen, Peter; Frejstrup Suhr, Lau; Sebastian Rodriguez, Juan; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

    2016-09-01

    We present a successful experimental evaluation of 4 level Pulse Amplitude Modulation (4-PAM) and Duobinary modulation. An experimental performance evaluation is presented for Duobinary 4 PAM and other modulation formats. All modulation formants used, may be considered to be implemented in future Passive Optical Network (PON) class access networks with limited electrical bandwidth. We compared NRZ, Duobinary, 4-PAM and Duobinary 4-PAM operating at 9 Gbaud over 20 km single mode fiber. The results provides an insight and guidelines on the utilization of these advanced modulation formats.

  15. Performance Prediction of Commercial Thermoelectric Cooler Modules using the Effective Material Properties

    NASA Astrophysics Data System (ADS)

    Lee, HoSung; Attar, Alaa M.; Weera, Sean L.

    2015-06-01

    This work examines the validity of formulating the effective thermoelectric material properties as a way to predict thermoelectric module performance. The three maximum parameters (temperature difference, current, and cooling power) of a thermoelectric cooler were formulated on the basis of the hot junction temperature. Then, the effective material properties (Seebeck coefficient, electrical resistance, and thermal conductivity) were defined in terms of the three maximum parameters that were taken from either a commercial thermoelectric cooler module or the measurements. It is demonstrated that the simple standard equation with the effective material properties predicts well the performance curves of the four selected commercial products. Normalized parameters over the maximum parameters were also formulated to present the characteristics of the thermoelectric coolers along with the normalized charts. The normalized charts would be universal for a given thermoelectric material.

  16. Improving the performance of bright quantum dot single photon sources using temporal filtering via amplitude modulation

    PubMed Central

    Ates, Serkan; Agha, Imad; Gulinatti, Angelo; Rech, Ivan; Badolato, Antonio; Srinivasan, Kartik

    2013-01-01

    Single epitaxially-grown semiconductor quantum dots have great potential as single photon sources for photonic quantum technologies, though in practice devices often exhibit nonideal behavior. Here, we demonstrate that amplitude modulation can improve the performance of quantum-dot-based sources. Starting with a bright source consisting of a single quantum dot in a fiber-coupled microdisk cavity, we use synchronized amplitude modulation to temporally filter the emitted light. We observe that the single photon purity, temporal overlap between successive emission events, and indistinguishability can be greatly improved with this technique. As this method can be applied to any triggered single photon source, independent of geometry and after device fabrication, it is a flexible approach to improve the performance of systems based on single solid-state quantum emitters, which often suffer from excess dephasing and multi-photon background emission. PMID:23466520

  17. Performance Evaluation of the New Compound-Carrier-Modulated Signal for Future Navigation Signals

    PubMed Central

    Luo, Ruidan; Xu, Ying; Yuan, Hong

    2016-01-01

    Navigation Signal based on Compound Carrier (NSCC), is proposed as the potential future global navigation satellite system (GNSS) signal modulation scheme. NSCC, a kind of multi-carrier (MC) signal, is generated by superposition and multi-parameter adjustment of sub-carriers. Therefore, a judious choice of parameter configation is needed. The main objective of this paper is to investigate the performance of the NSCC which is influenced by these parameters and to demonstrate its structure characteristics and superiority, employing a comprehensive evaluation system. The results show that the proposed NSCC signal processes full spectral efficiency and limited out of band (OOB) emissions, satisfying the demands of crowed frequency resources. It also presents better performance in terms of spectral separation coefficients (SSCs), tracking accuracy, multipath mitigation capability and anti-jamming reduction compared with the legacy navigation signals. NSCC modulation represents a serious candidate for navigation satellite augmentation systems, especially for signals applied in challenging environments. PMID:26828494

  18. Performance Evaluation of the New Compound-Carrier-Modulated Signal for Future Navigation Signals.

    PubMed

    Luo, Ruidan; Xu, Ying; Yuan, Hong

    2016-01-01

    Navigation Signal based on Compound Carrier (NSCC), is proposed as the potential future global navigation satellite system (GNSS) signal modulation scheme. NSCC, a kind of multi-carrier (MC) signal, is generated by superposition and multi-parameter adjustment of sub-carriers. Therefore, a judious choice of parameter configation is needed. The main objective of this paper is to investigate the performance of the NSCC which is influenced by these parameters and to demonstrate its structure characteristics and superiority, employing a comprehensive evaluation system. The results show that the proposed NSCC signal processes full spectral efficiency and limited out of band (OOB) emissions, satisfying the demands of crowed frequency resources. It also presents better performance in terms of spectral separation coefficients (SSCs), tracking accuracy, multipath mitigation capability and anti-jamming reduction compared with the legacy navigation signals. NSCC modulation represents a serious candidate for navigation satellite augmentation systems, especially for signals applied in challenging environments. PMID:26828494

  19. Performance characterization of thin-film-silicon based solar modules under clouded and clear sky conditions in comparison to crystalline silicon modules

    NASA Astrophysics Data System (ADS)

    Weicht, J. A.; Rasch, R.; Behrens, G.; Hamelmann, F. U.

    2016-07-01

    For a precise prediction of the energy yield of amorphous ( a-Si) and amorphous-microcrystalline tandem ( a-Si/ μc-Si) thinfilm-silicon photovoltaic (PV) modules it is important to know their performance ratio under different light conditions. The efficiency of solar modules is an important value for the monitoring and planning of PV-systems. The efficiency of a-Si solar modules shows no significant changes in the performance ratio at clouded or clear sky conditions. The efficiency of crystalline silicon-based ( c-Si) and a-Si/ μc-Si solar modules shows a lower efficiency for fully clouded conditions without direct irradiation compared to conditions with direct irradiation (clear sky). [Figure not available: see fulltext.

  20. High-performance deployable structures for the support of high-concentration ratio solar array modules

    NASA Technical Reports Server (NTRS)

    Mobrem, M.

    1985-01-01

    A study conducted on high-performance deployable structures for the support of high-concentration ratio solar array modules is discussed. Serious consideration is being given to the use of high-concentration ratio solar array modules or applications such as space stations. These concentrator solar array designs offer the potential of reduced cost, reduced electrical complexity, higher power per unit area, and improved survivability. Arrays of concentrators, such as the miniaturized Cassegrainian concentrator modules, present a serious challenge to the structural design because their mass per unit area (5.7 kg/square meters) is higher than that of flexible solar array blankets, and the requirement for accurate orientation towards the Sun (plus or minus 0.5 degree) requires structures with improved accuracy potentials. In addition, use on a space station requires relatively high structural natural frequencies to avoid deleterious interactions with control systems and other large structural components. The objective here is to identify and evaluate conceptual designs of structures suitable for deploying and accurately supporting high-concentration ratio solar array modules.

  1. Performance of a solar-heating module for commercial-greenhouse use: Phase V. Final report

    SciTech Connect

    Buchanan, J.M.

    1981-01-01

    A large solar heat collector was constructed to assist the heat loads of a commercial greenhouse. The collector is an insulated, black-cavity with forced-air circulating to transfer the solar energy to water storage via air-to-water heat exchangers. Performance records reported herein indicate that the annual collection is 20% of the solar radiation received, and lower than the 50% originally estimated. The result is that the years before positive cash flow is increased from 10 to 25 years for a typical projection study. Recommendations are made for improving the solar collection module which, currently, has a performance that does not recommend its cavity-type design.

  2. High-Performance Silicon-Germanium-Based Thermoelectric Modules for Gas Exhaust Energy Scavenging

    NASA Astrophysics Data System (ADS)

    Romanjek, K.; Vesin, S.; Aixala, L.; Baffie, T.; Bernard-Granger, G.; Dufourcq, J.

    2015-06-01

    Some of the energy used in transportation and industry is lost as heat, often at high-temperatures, during conversion processes. Thermoelectricity enables direct conversion of heat into electricity, and is an alternative to the waste-heat-recovery technology currently used, for example turbines and other types of thermodynamic cycling. The performance of thermoelectric (TE) materials and modules has improved continuously in recent decades. In the high-temperature range ( T hot side > 500°C), silicon-germanium (SiGe) alloys are among the best TE materials reported in the literature. These materials are based on non-toxic elements. The Thermoelectrics Laboratory at CEA (Commissariat à l'Energie Atomique et aux Energies Alternatives) has synthesized n and p-type SiGe pellets, manufactured TE modules, and integrated these into thermoelectric generators (TEG) which were tested on a dedicated bench with hot air as the source of heat. SiGe TE samples of diameter 60 mm were created by spark-plasma sintering. For n-type SiGe doped with phosphorus the peak thermoelectric figure of merit reached ZT = 1.0 at 700°C whereas for p-type SiGe doped with boron the peak was ZT = 0.75 at 700°C. Thus, state-of-the-art conversion efficiency was obtained while also achieving higher production throughput capacity than for competing processes. A standard deviation <4% in the electrical resistance of batches of ten pellets of both types was indicative of high reproducibility. A silver-paste-based brazing technique was used to assemble the TE elements into modules. This assembly technique afforded low and repeatable electrical contact resistance (<3 nΩ m2). A test bench was developed for measuring the performance of TE modules at high temperatures (up to 600°C), and thirty 20 mm × 20 mm TE modules were produced and tested. The results revealed the performance was reproducible, with power output reaching 1.9 ± 0.2 W for a 370 degree temperature difference. When the temperature

  3. High-performance GaAs/AlGaAs optical phase modulators for microwave photonic integrated circuits

    SciTech Connect

    Hietala, V.M.; Kravitz, S.H.; Armendariz, M.G.; Vawter, G.A.; Carson, R.F.

    1994-03-01

    A high-performance high-speed optical phase modulator for photonic integrated circuit (PIC) use is described. Integration of these optical phase modulators into a real system (compass) is also discussed. The optical phase modulators are based on depletion-edge translation and have experimentally provided optical phase shifts in excess of 60{degrees}/V{center_dot}mm with approximately 4 dB/cm loss while simultaneously demonstrating bandwidths in excess of 10 GHz.

  4. Weathering and durability of PV backsheets and impact on PV module performance

    NASA Astrophysics Data System (ADS)

    Gambogi, W.; Heta, Y.; Hashimoto, K.; Kopchick, J.; Felder, T.; MacMaster, S.; Bradley, A.; Hamzavytehraney, B.; Felix, V.; Aoki, T.; Stika, K.; Garreau-Illes, L.; Trout, T. J.

    2013-09-01

    Polymeric backsheets form the outer protective layer of most crystalline and multi-crystalline silicon cell photovoltaic panels. The mechanical, electrical, optical and chemical properties and durability of these backsheets are critical to the long term reliability, durability and safety of the photovoltaic modules. The stability of these backsheet properties is typically determined based on accelerated testing using individual stresses. However, the impact of multiple stresses applied sequentially or simultaneously can lead to changes in materials properties that are more predictive of performance in the field. An important consideration in the development of accelerated test protocols is the level and duration of the stress, including temperature variation, light intensity and spectral power distribution, humidity, rainfall and powered module current. In this paper, we discuss observations of the aging and degradation of solar panel from the field. Then how these changes correlate to accelerated testing results, and how accelerated tests can be modified to better match observations in the field.

  5. Performance evaluation of peak-clipped optical BPSK-SSB modulated signal.

    PubMed

    Sampath, K I Amila; Takano, Katsumi

    2015-07-27

    This study examines the performance of peak-clipped optical BPSK-SSB signal. The effectiveness of peak clipping for PAPR reduction and the degradation caused by peak clipping are numerically analyzed. PAPR of optical BPSK-SSB signal becomes high because of the peaky Hilbert-transformed signal component. PAPR improvement of 43.7% is attained by clipping the peaks of the Hilbert-transformed signal. Assessment of spectral degradation reveals that both waveform clipping and modulator nonlinearity contribute to sideband suppression degradation. Analyses of the 100-km transmitted signal results show that PAPR reduction by peak clipping alleviates the nonlinear phase shift caused by self-phase modulation (SPM), which produces a less degraded signal at the detector. Peak clipping can improve the SPM threshold of the studied system by 2.63 dB. PMID:26367640

  6. Electrostatic performance improvement of dual material cylindrical gate MOSFET using work-function modulation technique

    NASA Astrophysics Data System (ADS)

    Jena, Biswajit; Dash, Sidhartha; Mishra, Guru Prasad

    2016-09-01

    In a continuous effort to increase the DC and RF figure-of-merits (FOMs), multigate MOSFETs have evolved from classical planar device into a gate all around structure. The unique design with accuracy in device performance has made it a cutting edge device to overcome the scaling and performance barrier of the present VLSI technology. The fabrication process of a surface channel device with proper threshold voltage (Vth) directly depends upon the work-function of the gate electrode. By keeping it in mind, a metal gate with linearly modulated work-function (5-4.2 ev) along the z-axis in a cylindrical surrounding gate MOSFET is introduced. This work demonstrates the potential benefits of work-function modulation based dual material cylindrical gate MOSFET (WMDMCG) in terms of DC performance characteristics. The present model provides improved DC performance as compared to conventional dual material cylindrical surrounding gate MOSFET (DMCG) and the results obtained are validated with TCAD device simulator from Synopsys.

  7. Electrostatic performance improvement of dual material cylindrical gate MOSFET using work-function modulation technique

    NASA Astrophysics Data System (ADS)

    Jena, Biswajit; Dash, Sidhartha; Mishra, Guru Prasad

    2016-09-01

    In a continuous effort to increase the DC and RF figure-of-merits (FOMs), multigate MOSFETs have evolved from classical planar device into a gate all around structure. The unique design with accuracy in device performance has made it a cutting edge device to overcome the scaling and performance barrier of the present VLSI technology. The fabrication process of a surface channel device with proper threshold voltage (Vth) directly depends upon the work-function of the gate electrode. By keeping it in mind, a metal gate with linearly modulated work-function (5-4.2 ev) along the z-axis in a cylindrical surrounding gate MOSFET is introduced. This work demonstrates the potential benefits of work-function modulation based dual material cylindrical gate MOSFET (WMDMCG) in terms of DC performance characteristics. The present model provides improved DC performance as compared to conventional dual material cylindrical surrounding gate MOSFET (DMCG) and the results obtained are validated with TCAD device simulator from Synopsys.

  8. Performance/Program Budgeting. Module Number Six of Policy/Program Analysis and Evaluation Techniques, Package VI.

    ERIC Educational Resources Information Center

    Steiss, Alan Walter

    This packet contains the instructional materials necessary for presentation of the sixth of ten modules which comprise a portion of the National Training and Development Service Urban Management Curriculum Development Project. This module focuses on performance/program budgeting which combines and extends fiscal planning and control elements from…

  9. Performance Auditing. Material for Class Leader. Module Number Nine of Policy/Program Analysis and Evaluation Techniques, Package VI.

    ERIC Educational Resources Information Center

    Herbert, Leo

    This packet contains the materials necessary for presentation of the ninth of ten modules which comprise a portion of the National Training and Development Service Urban Management Curriculum Development Project. This module focuses on performance auditing which evaluates activities and operational efficiency by reviewing finances, management…

  10. Materials and Modules for Low Cost, High Performance Fuel Cell Humidifiers

    SciTech Connect

    Johnson, William B

    2012-12-31

    The objective of this program was to demonstrate a durable, high performance water transport membrane; and a compact, low-cost, membrane-based module utilizing that membrane for use in an automotive, stationary and/or portable fuel cell water transport exchangers. Over the past 20 years, great technical progress has been made in improving power density and durability of fuel cell stacks. Yet, operating durably at high performance levels under very dry conditions, e.g., < 20% RH at 80°C or above, remains beyond even the best fuel cell membrane electrode assemblies. Thus, today it is essential to humidify the gases supplied to the fuel cell inlets. In this work, we have produced a new, inexpensive, composite membrane capable of very high water vapor transport and low air cross-over. The composite structure consists of a very thin ionomer layer (e.g., < 5 micron) sandwiched between two microporous polymer layers. The thin ionomer layer facilitates the rapid water transport and provides an impermeable layer to prevent gas cross-over. Such an approach reduces cost, but maintains performance. The microporous layer protects the thin ionomer layer from mechanical damage during handling; confers strength to the thin layer allowing it to be more durable during use; and allows it to withstand higher automotive pressures and temperatures. The composite structure will therefore allow lower total cost while still meeting automotive humidifier water transport and durability targets. Because the transport rates of these new materials are so high, existing planar membrane humidifier module designs available at the start of the program were incapable of efficiently utilizing the high rates. Therefore, the assembled team designed, tested and demonstrated an innovative, low-cost humidifier module with customized channel geometries that can take advantage of the high the water transport rates. The objectives of the program have been fully met. The optimized membrane produced in the

  11. Tonal cues modulate line bisection performance: preliminary evidence for a new rehabilitation prospect?

    PubMed

    Ishihara, Masami; Revol, Patrice; Jacquin-Courtois, Sophie; Mayet, Romaine; Rode, Gilles; Boisson, Dominique; Farnè, Alessandro; Rossetti, Yves

    2013-01-01

    The effect of the presentation of two different auditory pitches (high and low) on manual line-bisection performance was studied to investigate the relationship between space and magnitude representations underlying motor acts. Participants were asked to mark the midpoint of a given line with a pen while they were listening a pitch via headphones. In healthy participants, the effect of the presentation order (blocked or alternative way) of auditory stimuli was tested (Experiment 1). The results showed no biasing effect of pitch in blocked-order presentation, whereas the alternative presentation modulated the line-bisection. Lower pitch produced leftward or downward bisection biases whereas higher pitch produced rightward or upward biases, suggesting that visuomotor processing can be spatially modulated by irrelevant auditory cues. In Experiment 2, the effect of such alternative stimulations in line bisection in right brain damaged patients with a unilateral neglect and without a neglect was tested. Similar biasing effects caused by auditory cues were observed although the white noise presentation also affected the patient's performance. Additionally, the effect of pitch difference was larger for the neglect patient than for the no-neglect patient as well as for healthy participants. The neglect patient's bisection performance gradually improved during the experiment and was maintained even after 1 week. It is therefore, concluded that auditory cues, characterized by both the pitch difference and the dynamic alternation, influence spatial representations. The larger biasing effect seen in the neglect patient compared to the no-neglect patient and healthy participants suggests that auditory cues could modulate the direction of the attentional bias that is characteristic of neglect patients. Thus, the alternative presentation of auditory cues could be used as rehabilitation for neglect patients. The space-pitch associations are discussed in terms of a generalized

  12. Performance modulation of α-MnO2 nanowires by crystal facet engineering

    PubMed Central

    Li, Wenxian; Cui, Xiangyuan; Zeng, Rong; Du, Guodong; Sun, Ziqi; Zheng, Rongkun; Ringer, Simon P.; Dou, Shi Xue

    2015-01-01

    Modulation of material physical and chemical properties through selective surface engineering is currently one of the most active research fields, aimed at optimizing functional performance for applications. The activity of exposed crystal planes determines the catalytic, sensory, photocatalytic, and electrochemical behavior of a material. In the research on nanomagnets, it opens up new perspectives in the fields of nanoelectronics, spintronics, and quantum computation. Herein, we demonstrate controllable magnetic modulation of α-MnO2 nanowires, which displayed surface ferromagnetism or antiferromagnetism, depending on the exposed plane. First-principles density functional theory calculations confirm that both Mn- and O-terminated α-MnO2 (1 1 0) surfaces exhibit ferromagnetic ordering. The investigation of surface-controlled magnetic particles will lead to significant progress in our fundamental understanding of functional aspects of magnetism on the nanoscale, facilitating rational design of nanomagnets. Moreover, we approved that the facet engineering pave the way on designing semiconductors possessing unique properties for novel energy applications, owing to that the bandgap and the electronic transport of the semiconductor can be tailored via exposed surface modulations. PMID:25758232

  13. Coupling a transient solvent extraction module with the separations and safeguards performance model.

    SciTech Connect

    DePaoli, David W.; Birdwell, Joseph F.; Gauld, Ian C.; Cipiti, Benjamin B.; de Almeida, Valmor F.

    2009-10-01

    A number of codes have been developed in the past for safeguards analysis, but many are dated, and no single code is able to cover all aspects of materials accountancy, process monitoring, and diversion scenario analysis. The purpose of this work was to integrate a transient solvent extraction simulation module developed at Oak Ridge National Laboratory, with the Separations and Safeguards Performance Model (SSPM), developed at Sandia National Laboratory, as a first step toward creating a more versatile design and evaluation tool. The SSPM was designed for materials accountancy and process monitoring analyses, but previous versions of the code have included limited detail on the chemical processes, including chemical separations. The transient solvent extraction model is based on the ORNL SEPHIS code approach to consider solute build up in a bank of contactors in the PUREX process. Combined, these capabilities yield a more robust transient separations and safeguards model for evaluating safeguards system design. This coupling and initial results are presented. In addition, some observations toward further enhancement of separations and safeguards modeling based on this effort are provided, including: items to be addressed in integrating legacy codes, additional improvements needed for a fully functional solvent extraction module, and recommendations for future integration of other chemical process modules.

  14. Coupling a Transient Solvent Extraction Module with the Separations and Safeguards Performance Model

    SciTech Connect

    de Almeida, Valmor F; Birdwell Jr, Joseph F; DePaoli, David W; Gauld, Ian C

    2009-10-01

    A past difficulty in safeguards design for reprocessing plants is that no code existed for analysis and evaluation of the design. A number of codes have been developed in the past, but many are dated, and no single code is able to cover all aspects of materials accountancy, process monitoring, and diversion scenario analysis. The purpose of this work was to integrate a transient solvent extraction simulation module developed at Oak Ridge National Laboratory, with the SSPM Separations and Safeguards Performance Model, developed at Sandia National Laboratory, as a first step toward creating a more versatile design and evaluation tool. The SSPM was designed for materials accountancy and process monitoring analyses, but previous versions of the code have included limited detail on the chemical processes, including chemical separations. The transient solvent extraction model is based on the ORNL SEPHIS code approach to consider solute build up in a bank of contactors in the PUREX process. Combined, these capabilities yield a much more robust transient separations and safeguards model for evaluating safeguards system design. This coupling and the initial results are presented. In addition, some observations toward further enhancement of separations and safeguards modeling based on this effort are provided, including: items to be addressed in integrating legacy codes, additional improvements needed for a fully functional solvent extraction module, and recommendations for future integration of other chemical process modules.

  15. Performance of the unique-word-reverse-modulation type demodulator for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Dohi, Tomohiro; Nitta, Kazumasa; Ueda, Takashi

    1993-01-01

    This paper proposes a new type of coherent demodulator, the unique-word (UW)-reverse-modulation type demodulator, for burst signal controlled by voice operated transmitter (VOX) in mobile satellite communication channels. The demodulator has three individual circuits: a pre-detection signal combiner, a pre-detection UW detector, and a UW-reverse-modulation type demodulator. The pre-detection signal combiner combines signal sequences received by two antennas and improves bit energy-to-noise power density ratio (E(sub b)/N(sub 0)) 2.5 dB to yield 10(exp -3) average bit error rate (BER) when carrier power-to-multipath power ratio (CMR) is 15 dB. The pre-detection UW detector improves UW detection probability when the frequency offset is large. The UW-reverse-modulation type demodulator realizes a maximum pull-in frequency of 3.9 kHz, the pull-in time is 2.4 seconds and frequency error is less than 20 Hz. The performances of this demodulator are confirmed through computer simulations and its effect is clarified in real-time experiments at a bit rate of 16.8 kbps using a digital signal processor (DSP).

  16. An assessment of the optical performance of stretched-membrane mirror modules

    SciTech Connect

    Alpert, D.J.; Houser, R.M.

    1988-01-01

    The United States Department of Energy's solar thermal program is developing an innovative concept for the heliostats used in a solar central-receiver power plant: replacing the familiar glass mirrors with stretched-membrane reflectors. This paper presents Sandia's assessment of first- and second-generation mirror modules made of stretched membranes. The first of these prototype mirror modules were built in 1986 by two contractors to Sandia. Solar Kinetics, Inc., produced a module with optical characteristics equaling those of heliostats that use glass mirrors. The first design produced by Science Applications International Corp. proved to be unworkable. Using the experience gained with the first models, the same two contractors are currently building improved prototypes. The improved designs will be easier to fabricate and will perform better than the first-generation designs. SAIC's second design has been installed at the Central Receiver Test Facility, and Sandia's preliminary assessment shows the quality of its beam to be as good as SKI's original design. SKI is currently in the process of installing its second prototype. The final paper will include detailed results of the second-generation prototypes' beam quality, focusing systems, defocusing capabilities, and durability. 23 refs., 6 figs.

  17. Observing object lifting errors modulates cortico-spinal excitability and improves object lifting performance.

    PubMed

    Buckingham, Gavin; Wong, Jeremy D; Tang, Minnie; Gribble, Paul L; Goodale, Melvyn A

    2014-01-01

    Observing the actions of others has been shown to modulate cortico-spinal excitability and affect behaviour. However, the sensorimotor consequences of observing errors are not well understood. Here, participants watched actors lift identically weighted large and small cubes which typically elicit expectation-based fingertip force errors. One group of participants observed the standard overestimation and underestimation-style errors that characterise early lifts with these cubes (Error video--EV). Another group watched the same actors performing the well-adapted error-free lifts that characterise later, well-practiced lifts with these cubes (No error video--NEV). We then examined actual object lifting performance in the subjects who watched the EV and NEV. Despite having similar cognitive expectations and perceptions of heaviness, the group that watched novice lifters making errors themselves made fewer overestimation-style errors than those who watched the expert lifts. To determine how the observation of errors alters cortico-spinal excitability, we measured motor evoked potentials in separate group of participants while they passively observed these EV and NEV. Here, we noted a novel size-based modulation of cortico-spinal excitability when observing the expert lifts, which was eradicated when watching errors. Together, these findings suggest that individuals' sensorimotor systems are sensitive to the subtle visual differences between observing novice and expert performance.

  18. Monolithic interconnected module with a tunnel junction for enhanced electrical and optical performance

    DOEpatents

    Murray, Christopher S.; Wilt, David M.

    2000-01-01

    An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMS), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

  19. The design and performance estimates for the propulsion module for the booster of a TSTO vehicle

    NASA Astrophysics Data System (ADS)

    Snyder, Christopher A.; Maldonado, Jaime J.

    1991-09-01

    A NASA study of propulsion systems for possible low-risk replacements for the Space Shuttle is presented. Results of preliminary studies to define the USAF two-stage-to-orbit (TSTO) concept to deliver 10,000 pounds to low polar orbit are described. The booster engine module consists of an over/under turbine bypass engines/ramjet engine design for acceleration from takeoff to the staging point of Mach 6.5 and approximately 100,000 feet altitude. Propulsion system performance and weight are presented with preliminary mission study results of vehicle size.

  20. A Monolithic Interconnected module with a tunnel Junction for Enhanced Electrical and Optical Performance

    SciTech Connect

    Murray, Christopher Sean; Wilt, David Morgan

    1999-06-30

    An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMs), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

  1. Effects of communication training on real practice performance: a role-play module versus a standardized patient module.

    PubMed

    Schlegel, Claudia; Woermann, Ulrich; Shaha, Maya; Rethans, Jan-Joost; van der Vleuten, Cees

    2012-01-01

    This study investigated the effectiveness of modules involving standardized patients and role-plays on training communication skills. The first module involved standardized patients and an Objective Structured Clinical Examination (OSCE); the second module consisted of peer role-plays and a written examination. A randomized posttest-only control group design with first-year nursing students was used. The intervention group received one-to-one communication training with direct oral feedback from the standardized patient. The control group had training with peer role-playing and mutual feedback. The posttest involved students' rating their self-efficacy, and real patients and clinical supervisors evaluated their communication skills. No significant differences were found between self-efficacy and patient ratings. However, the clinical supervisors rated the intervention group's communication skills to be significantly (p < 0.0001) superior. Assessments by clinical supervisors indicate that communication training modules including standardized patients and an OSCE are superior to communication training modules with peer role-playing. PMID:22085207

  2. Effects of communication training on real practice performance: a role-play module versus a standardized patient module.

    PubMed

    Schlegel, Claudia; Woermann, Ulrich; Shaha, Maya; Rethans, Jan-Joost; van der Vleuten, Cees

    2012-01-01

    This study investigated the effectiveness of modules involving standardized patients and role-plays on training communication skills. The first module involved standardized patients and an Objective Structured Clinical Examination (OSCE); the second module consisted of peer role-plays and a written examination. A randomized posttest-only control group design with first-year nursing students was used. The intervention group received one-to-one communication training with direct oral feedback from the standardized patient. The control group had training with peer role-playing and mutual feedback. The posttest involved students' rating their self-efficacy, and real patients and clinical supervisors evaluated their communication skills. No significant differences were found between self-efficacy and patient ratings. However, the clinical supervisors rated the intervention group's communication skills to be significantly (p < 0.0001) superior. Assessments by clinical supervisors indicate that communication training modules including standardized patients and an OSCE are superior to communication training modules with peer role-playing.

  3. Advanced Materials for High Temperature, High Performance, Wide Bandgap Power Modules

    NASA Astrophysics Data System (ADS)

    O'Neal, Chad B.; McGee, Brad; McPherson, Brice; Stabach, Jennifer; Lollar, Richard; Liederbach, Ross; Passmore, Brandon

    2016-01-01

    Advanced packaging materials must be utilized to take full advantage of the benefits of the superior electrical and thermal properties of wide bandgap power devices in the development of next generation power electronics systems. In this manuscript, the use of advanced materials for key packaging processes and components in multi-chip power modules will be discussed. For example, to date, there has been significant development in silver sintering paste as a high temperature die attach material replacement for conventional solder-based attach due to the improved thermal and mechanical characteristics as well as lower processing temperatures. In order to evaluate the bond quality and performance of this material, shear strength, thermal characteristics, and void quality for a number of silver sintering paste materials were analyzed as a die attach alternative to solder. In addition, as high voltage wide bandgap devices shift from engineering samples to commercial components, passivation materials become key in preventing premature breakdown in power modules. High temperature, high dielectric strength potting materials were investigated to be used to encapsulate and passivate components internal to a power module. The breakdown voltage up to 30 kV and corresponding leakage current for these materials as a function of temperature is also presented. Lastly, high temperature plastic housing materials are important for not only discrete devices but also for power modules. As the operational temperature of the device and/or ambient temperature increases, the mechanical strength and dielectric properties are dramatically reduced. Therefore, the electrical characteristics such as breakdown voltage and leakage current as a function of temperature for housing materials are presented.

  4. Performance of the Vanguard Solar Dish-Stirling Engine Module. Final report

    SciTech Connect

    Droher, J.J.; Squier, S.E.

    1986-07-01

    This report summarizes information on the performance of the Vanguard Parabolic Dish/Stirling Engine Module during an 18-month period of operational testing (February 1984 through July 1985) at Rancho Mirage, California. The test module consisted of a 10.7-m-diameter parabolic dish to collect and concentrate solar beam radiation, a solar receiver, a four-cylinder Stirling engine using hydrogen as the working gas, an induction generator, and an air-cooled radiator. Historical beam insolation data are summarized for the Palm Springs area. Gross and net output of electricity, auxiliary power requirements, system availability, and capacity factors are summarized on a monthly and annual basis. Models are presented for predicting electrical output. Operating and maintenance experience is delineated chronologically and by subsystem. The performance of each major subsystem is discussed. An assessment is made of the present and future status of the dish/Stirling system. Recommendations are made for future developmental work involving dish/Stirling applications for the utility industry.

  5. Modulating memristive performance of hexagonal WO3 nanowire by water-oxidized hydrogen ion implantation.

    PubMed

    Zhou, Yong; Peng, Yuehua; Yin, Yanling; Zhou, Fang; Liu, Chang; Ling, Jing; Lei, Le; Zhou, Weichang; Tang, Dongsheng

    2016-01-01

    In a two-terminal Au/hexagonal WO3 nanowire/Au device, ions drifting or carriers self-trapping under external electrical field will modulate the Schottky barriers between the nanowire and electrodes, and then result in memristive effect. When there are water molecules adsorbed on the surface of WO3 nanowire, hydrogen ions will generate near the positively-charged electrode and transport in the condensed water film, which will enhance the memristive performance characterized by analogic resistive switching remarkably. When the bias voltage is swept repeatedly under high relative humidity level, hydrogen ions will accumulate on the surface and then implant into the lattice of the WO3 nanowire, which leads to a transition from semiconducting WO3 nanowire to metallic HxWO3 nanowire. This insulator-metal transition can be realized more easily after enough electron-hole pairs being excited by laser illumination. The concentration of hydrogen ions in HxWO3 nanowire will decrease when the device is exposed to oxygen atmosphere or the bias voltage is swept in atmosphere with low relative humidity. By modulating the concentration of hydrogen ions, conductive hydrogen tungsten bronze filament might form or rupture near electrodes when the polarity of applied voltage changes, which will endow the device with memristive performance characterized by digital resistive switching. PMID:27600368

  6. Modulating memristive performance of hexagonal WO3 nanowire by water-oxidized hydrogen ion implantation

    PubMed Central

    Zhou, Yong; Peng, Yuehua; Yin, Yanling; Zhou, Fang; Liu, Chang; Ling, Jing; Lei, Le; Zhou, Weichang; Tang, Dongsheng

    2016-01-01

    In a two-terminal Au/hexagonal WO3 nanowire/Au device, ions drifting or carriers self-trapping under external electrical field will modulate the Schottky barriers between the nanowire and electrodes, and then result in memristive effect. When there are water molecules adsorbed on the surface of WO3 nanowire, hydrogen ions will generate near the positively-charged electrode and transport in the condensed water film, which will enhance the memristive performance characterized by analogic resistive switching remarkably. When the bias voltage is swept repeatedly under high relative humidity level, hydrogen ions will accumulate on the surface and then implant into the lattice of the WO3 nanowire, which leads to a transition from semiconducting WO3 nanowire to metallic HxWO3 nanowire. This insulator-metal transition can be realized more easily after enough electron-hole pairs being excited by laser illumination. The concentration of hydrogen ions in HxWO3 nanowire will decrease when the device is exposed to oxygen atmosphere or the bias voltage is swept in atmosphere with low relative humidity. By modulating the concentration of hydrogen ions, conductive hydrogen tungsten bronze filament might form or rupture near electrodes when the polarity of applied voltage changes, which will endow the device with memristive performance characterized by digital resistive switching. PMID:27600368

  7. Performance of motor imagery brain-computer interface based on anodal transcranial direct current stimulation modulation.

    PubMed

    Wei, Pengfei; He, Wei; Zhou, Yi; Wang, Liping

    2013-05-01

    Voluntarily modulating neural activity plays a key role in brain-computer interface (BCI). In general, the self-regulated neural activation patterns are used in the current BCI systems involving the repetitive trainings with feedback for an attempt to achieve a high-quality control performance. With the limitation posed by the training procedure in most BCI studies, the present work aims to investigate whether directly modulating the neural activity by using an external method could facilitate the BCI control. We designed an experimental paradigm that combines anodal transcranial direct current stimulation (tDCS) with a motor imagery (MI)-based feedback EEG BCI system. Thirty-two young and healthy human subjects were randomly assigned to the real and sham stimulation groups to evaluate the effect of tDCS-induced EEG pattern changes on BCI classification accuracy. Results showed that the anodal tDCS obviously induces sensorimotor rhythm (SMR)-related event-related desynchronization (ERD) pattern changes in the upper-mu (10-14 Hz) and beta (14-26 Hz) rhythm components. Both the online and offline BCI classification results demonstrate that the enhancing ERD patterns could conditionally improve BCI performance. This pilot study suggests that the tDCS is a promising method to help the users to develop reliable BCI control strategy in a relatively short time.

  8. Modulating memristive performance of hexagonal WO3 nanowire by water-oxidized hydrogen ion implantation.

    PubMed

    Zhou, Yong; Peng, Yuehua; Yin, Yanling; Zhou, Fang; Liu, Chang; Ling, Jing; Lei, Le; Zhou, Weichang; Tang, Dongsheng

    2016-01-01

    In a two-terminal Au/hexagonal WO3 nanowire/Au device, ions drifting or carriers self-trapping under external electrical field will modulate the Schottky barriers between the nanowire and electrodes, and then result in memristive effect. When there are water molecules adsorbed on the surface of WO3 nanowire, hydrogen ions will generate near the positively-charged electrode and transport in the condensed water film, which will enhance the memristive performance characterized by analogic resistive switching remarkably. When the bias voltage is swept repeatedly under high relative humidity level, hydrogen ions will accumulate on the surface and then implant into the lattice of the WO3 nanowire, which leads to a transition from semiconducting WO3 nanowire to metallic HxWO3 nanowire. This insulator-metal transition can be realized more easily after enough electron-hole pairs being excited by laser illumination. The concentration of hydrogen ions in HxWO3 nanowire will decrease when the device is exposed to oxygen atmosphere or the bias voltage is swept in atmosphere with low relative humidity. By modulating the concentration of hydrogen ions, conductive hydrogen tungsten bronze filament might form or rupture near electrodes when the polarity of applied voltage changes, which will endow the device with memristive performance characterized by digital resistive switching.

  9. Augmenting data rate performance for higher order modulation in triangular index profile multicore fiber interconnect

    NASA Astrophysics Data System (ADS)

    Mishra, Jitendra K.; Priye, Vishnu; Rahman, B. M. A.

    2016-07-01

    A triangular profile multicore fiber (MCF) optical interconnect (OI) is investigated to augment performance that typically degrades at high data rates for higher order modulation in a short reach transmission system. Firstly, probability density functions (PDFs) variation with inter-core crosstalk is calculated for 8-core MCF OI with different index profile in the core and it was observed that the triangular profile MCF OI is the most crosstalk tolerant. Next, symbol error probability (SEP) for higher order quadrature phase shift keying (QPSK) modulated signal due to inter-core crosstalk is analytically obtained and their dependence on typical characteristic parameters are examined. Further, numerical simulations are carried out to compare the error performance of QPSK for step index and triangular index MCF OI by generating eye diagram at 40 Gbps per channel. Finally, it is shown that MCF OI with triangular index profile supporting QPSK has double spectral efficiency with tolerable trade off in SEP as compared with those of binary phase shift keying (BPSK) at high data rates which is scalable up to 5 Tbps.

  10. Performance Evaluation Workshop for In-Service Managers. Module 4: Employee Feedback and Development. The Urban Management Curriculum Development Project, Package XIV.

    ERIC Educational Resources Information Center

    Scontrino, M. Peter

    This is the fourth module in a four-module training package for use in inservice seminars or workshops on performance appraisal and employee development. Module 4 addresses employee feedback and counseling aspects of performance evaluation. Primary emphasis is on use of performance reviews as employee development tools. Two related content areas…

  11. Modelling the performance of USV manoeuvring and target tracking: an approach using frequency modulated continuous wave radar rotary system.

    PubMed

    Onunka, Chiemela; Nnadozie, Remigius Chidozie

    2013-12-01

    The performance of frequency modulated continuous wave (FMCW) radar in tracking targets is presented and analysed. Obstacle detection, target tracking and radar target tracking performance models are developed and were used to investigate and to propose ways of improving the autonomous motion of unmanned surface vehicle (USV). Possible factors affecting the performance of FMCW radar in tracking targets are discussed and analysed. PMID:23853743

  12. Rationally engineered Troponin C modulates in vivo cardiac function and performance in health and disease

    PubMed Central

    Shettigar, Vikram; Zhang, Bo; Little, Sean C.; Salhi, Hussam E.; Hansen, Brian J.; Li, Ning; Zhang, Jianchao; Roof, Steve R.; Ho, Hsiang-Ting; Brunello, Lucia; Lerch, Jessica K.; Weisleder, Noah; Fedorov, Vadim V.; Accornero, Federica; Rafael-Fortney, Jill A.; Gyorke, Sandor; Janssen, Paul M. L.; Biesiadecki, Brandon J.; Ziolo, Mark T.; Davis, Jonathan P.

    2016-01-01

    Treatment for heart disease, the leading cause of death in the world, has progressed little for several decades. Here we develop a protein engineering approach to directly tune in vivo cardiac contractility by tailoring the ability of the heart to respond to the Ca2+ signal. Promisingly, our smartly formulated Ca2+-sensitizing TnC (L48Q) enhances heart function without any adverse effects that are commonly observed with positive inotropes. In a myocardial infarction (MI) model of heart failure, expression of TnC L48Q before the MI preserves cardiac function and performance. Moreover, expression of TnC L48Q after the MI therapeutically enhances cardiac function and performance, without compromising survival. We demonstrate engineering TnC can specifically and precisely modulate cardiac contractility that when combined with gene therapy can be employed as a therapeutic strategy for heart disease. PMID:26908229

  13. On the performance of Trellis coded modulation with octal phase shift keying over the TDRSS channel

    NASA Technical Reports Server (NTRS)

    Osborne, William P.; Wolcott, Ted J.; Kopp, Brian T.; Ross, Michael

    1993-01-01

    As the National Aeronautics and Space Administration moves into the 21st century with programs like Space Station Freedom, a manned mission to Mars, and the new Landsat mission, transmission demands on the Tracking and Data Relay Satellite System (TDRSS) will very likely exceed the available bandwidth. The Manual Lujan, Jr. Center for Space Telemetering and Telecommunications Systems (CSTTS) at New Mexico State University (NMSU) is studying techniques for increasing the data rate capabilities of TDRSS. These techniques include the use of advanced bandwidth efficient modulation formats to increase the data rate that can be sustained in a TDRSS transponder and the use of lossless bandwidth compression of the data to be transmitted to lower the data rate required from the user spacecraft. Based upon current technology the most promising bandwidth efficient modulation technique is Trellis Coded Modulation (TCM) operating with Octal Phase shift Keying (8PSK). Trellis Coded Modulation coding with 8PSK carrier modulation has the capability to increase the data rate which can be transmitted through the TDRSS spacecraft by a factor of 2 to 2.5 times that available with todays coded QPSK systems with only a small penalty in link performance relative to the existing systems. However, before NASA can safely employ TCM coding it is necessary to prove that this complex format can perform on the real TDRSS link as it does in labs and simulation studies. This proof-of-concept test over a live satellite channel was the objective of the construction and testing performed under this task of the NMSU NASA grant referenced above. In conjunction with NASA, NMSU's CSTTS has constructed a system to test a new candidate TDRSS modulation scheme, TCM 8PSK, that can enhance the information throughput of the TDRSS spacecraft. The test system for this project which was constructed over a period of 18 months by NMSU consisted of two racks of commercial and univeristy-designed and -built

  14. Final Report: Materials and Modules for Low Cost, High Performance Fuel Cell Humidifiers

    SciTech Connect

    Johnson, William B

    2012-12-31

    Over the past 20 years, great technical progress has been made in improving power density and durability of fuel cell stacks. Yet, operating durably at high performance levels under very dry conditions, e.g., < 20% RH at 80 °C or above, remains beyond even the best fuel cell membrane electrode assemblies. Thus, today it is essential to humidify the gases supplied to the fuel cell inlets. In this work, we have produced a new, inexpensive, composite membrane capable of very high water vapor transport and low air cross-over. The composite structure consists of a very thin ionomer layer (e.g., < 5 m) sandwiched between two microporous polymer layers. The thin ionomer layer facilitates the rapid water transport and provides an impermeable layer to prevent gas cross-over. Such an approach reduces cost, but maintains performance. The microporous layer protects the thin ionomer layer from mechanical damage during handling; confers strength to the thin layer allowing it to be more durable during use; and allows it to withstand higher automotive pressures and temperatures. The composite structure will therefore allow lower total cost while still meeting automotive humidifier water transport and durability targets. Because the transport rates of these new materials are so high, existing planar membrane humidifier module designs available at the start of the program were incapable of efficiently utilizing the high rates. Therefore, the assembled team designed, tested and demonstrated an innovative, low-cost humidifier module with customized channel geometries that can take advantage of the high the water transport rates. Program Results The objectives of the program have been fully met. The optimized membrane produced in the program has very high transport rates, nearly twice that of the closest competitive option, a homogeneous perfluorosulfonic acid (PFSA) membrane. Furthermore, the composite structure imparts significant durability advantages, allowing the membrane to

  15. Performance analysis of an all-optical logic gate based on a single I/Q modulator with direct detection.

    PubMed

    Zhai, Yaxue; Tang, Xianfeng; Zhang, Xiaoguang; Xi, Lixia; Zhang, Wenbo

    2016-09-01

    This paper investigates the performance of an all-optical logic gate scheme based on a single in-phase and quadrature (I/Q) modulator with direct detection. The proposed scheme of an all-optical logic gate is simple, high speed, and easily reconfigured to realize 24 logic states by adjusting bias voltages, peak-to-peak voltages of the driven RF signals, and the phase shift. As the scheme to realize logic gates is based on the irregular use of a commercially available I/Q modulator and laser source, a specialized logic gate system including a laser, I/Q modulator, and driven RF module should be optimally designed to obtain the best performance. With the system's extinction ratio (ER) and Q-factor as metrics, the performance of the proposed logic gate scheme is analyzed theoretically and numerically in this paper. We first give a new theoretical model of the I/Q modulator. Next, taking the OR gate as an example, the simulations are carried out to analyze performance under the influence of some key factors in the system. Results show that the extinction ratio of the whole system is affected by the phase shift between the two arms of the I/Q modulator and the extinction ratios of two Mach-Zehnder modulators (MZMs), while Q-factor is further influenced by the output power of the laser and the insertion loss of the MZMs in the I/Q modulator. For an I/Q modulator with MZMs having an extinction ratio of 20 dB, the minimum laser output power to obtain a system's ER higher than 16 dB is 3 dBm, while in order to obtain a Q-factor higher than 6, the output power of the laser must not be <10  dBm. PMID:27607252

  16. Performance evaluation of intensity modulated optical OFDM system with digital baseband distortion.

    PubMed

    Vanin, Evgeny

    2011-02-28

    Bit-Error-Ratio (BER) of intensity modulated optical orthogonal frequency division multiplexing (OFDM) system is analytically evaluated accounting for nonlinear digital baseband distortion in the transmitter and additive noise in the photo receiver. The nonlinear distortion that is caused by signal clipping and quantization is taken into consideration. The signal clipping helps to overcome the system performance limitation related to high peak-to-average power ratio (PAPR) of the OFDM signal and to minimize the value of optical power that is required for achieving specified BER. The signal quantization due to a limited bit resolution of the digital to analog converter (DAC) causes an optical power penalty in the case when the bit resolution is too low. By introducing an effective signal to noise ratio (SNR) the optimum signal clipping ratio, system BER and required optical power at the input to the receiver is evaluated for the OFDM system with multi-level quadrature amplitude modulation (QAM) applied to the optical signal subcarriers. Minimum required DAC bit resolution versus the size of QAM constellation is identified. It is demonstrated that the bit resolution of 7 and higher causes negligibly small optical power penalty at the system BER=10⁻³ when 256-QAM and a constellation of lower size is applied. The performance of the optical OFDM system is compared to the performance of the multi-level amplitude-shift keying (M-ASK) system for the same number of information bits transmitted per signal sample. It is demonstrated that in the case of the matched receiver the M-ASK system outperforms OFDM and requires 3-3.5 dB less of optical power at BER=10⁻³ when 1-4 data bits are transmitted per signal sample. PMID:21369258

  17. Trait Anxiety Modulates Brain Activity during Performance of Verbal Fluency Tasks

    PubMed Central

    Gawda, Barbara; Szepietowska, Ewa

    2016-01-01

    Trait anxiety is thought to be associated with pathological anxiety, and a risk factor for psychiatric disorders. The present study examines the brain mechanisms associated with trait anxiety during the performing of verbal fluency tasks. The aim is to show how trait anxiety modulates executive functions as measured by verbal fluency, and to explore the link between verbal fluency and anxiety due to the putative negative biases in high-anxious individuals. Seven tasks of verbal fluency were used: letter “k,” “f,” verbs, “animals,” “vehicles,” “joy,” and “fear.” The results of 35 subjects (whole sample), and 17 subjects (nine men, eight women) selected from the whole sample for the low/high-anxious groups on the basis of Trait Anxiety scores were analyzed. The subjects were healthy, Polish speaking, right-handed and aged from 20 to 35 years old. fMRI (whole-brain analysis with FWE corrections) was used to show the neural signals under active participation in verbal fluency tasks. The results confirm that trait anxiety slightly modulates neural activation during the performance of verbal fluency tasks, especially in the more difficult tasks. Significant differences were found in brain activation during the performance of more complex tasks between individuals with low anxiety and those with high anxiety. Greater activation in the right hemisphere, frontal gyri, and cerebellum was found in people with low anxiety. The results reflect better integration of cognitive and affective capacities in individuals with low anxiety. PMID:26903827

  18. Prefrontal modulation of working memory performance in brain injury and disease.

    PubMed

    Hillary, Frank G; Genova, Helen M; Chiaravalloti, Nancy D; Rypma, Bart; DeLuca, John

    2006-11-01

    The inter-related cognitive constructs of working memory (WM) and processing speed are fundamental components to general intellectual functioning in humans. Importantly, both WM and processing speed are highly susceptible to disruption in cases of brain injury, neurologic illness, and even in normal aging. A goal of this article is to summarize and critique the functional imaging studies of speeded working memory in neurologically impaired populations. This review focuses specifically on the role of the lateral prefrontal cortex in mediating WM performance and integrates the relevant WM literature in healthy adults with the current findings in the clinical literature. One important finding emerging from a summary of this literature is the dissociable contributions made by ventrolateral and dorsolateral prefrontal cortex (VLPFC and DLPFC) in guiding performance on tasks of WM. Throughout this review, it is shown that when cerebral resources are challenged, it is DLPFC, and often right DLPFC specifically, that plays a critical role in modulating WM functioning. In addition, this article will examine the relationship between task performance and brain activation across studies to clarify the role of increased DLPFC activity in clinical samples. Finally, explanations are offered for the observed increased DLPFC activation and the potentially unique role of right DLPFC in mediating WM performance during periods of cerebral challenge.

  19. Fluoxetine modulates motor performance and cerebral activation of patients recovering from stroke.

    PubMed

    Pariente, J; Loubinoux, I; Carel, C; Albucher, J F; Leger, A; Manelfe, C; Rascol, O; Chollet, F

    2001-12-01

    In order to determine the influence of a single dose of fluoxetine on the cerebral motor activation of lacunar stroke patients in the early phase of recovery, we conducted a prospective, double-blind, crossover, placebo-controlled study on 8 patients with pure motor hemiparesia. Each patient underwent two functional magnetic resonance imaging (fMRI) examinations: one under fluoxetine and one under placebo. The first was performed 2 weeks after stroke onset and the second a week later. During the two fMRI examinations, patients performed an active controlled motor task with the affected hand and a passive one conducted by the examiner with the same hand. Motor performance was evaluated by motor tests under placebo and under fluoxetine immediately before the examinations to investigate the effect of fluoxetine on motor function. Under fluoxetine, during the active motor task, hyperactivation in the ipsilesional primary motor cortex was found. Moreover, fluoxetine significantly improved motor skills of the affected side. We found that a single dose of fluoxetine was enough to modulate cerebral sensory-motor activation in patients. This redistribution of activation toward the motor cortex output activation was associated with an enhancement of motor performance. PMID:11761469

  20. Monitoring of catalyst performance in CO2 lasers using frequency modulation spectroscopy with diode lasers

    NASA Technical Reports Server (NTRS)

    Wang, Liang-Guo; Sachse, Glen

    1990-01-01

    Closed-cycle CO2 laser operation with removal of O2 and regeneration of CO2 can be achieved by catalytic CO-O2 recombination. Both parametric studies of the optimum catalyst formulation and long-term performance tests require on line monitoring of CO, O2 and CO2 concentrations. There are several existing methods for molecular oxygen detection. These methods are either intrusive (such as electrochemical method or mass spectrometry) or very expensive (such as CARS, UV laser absorption). Researchers demonstrated a high-sensitivity spectroscopic measurement of O2 using the two-tone frequency modulation spectroscopy (FMS) technique with a near infrared GaAlAs diode laser. Besides its inexpensive cost, fast response time, nonintrusive measurements and high sensitivity, this technique may also be used to differentiate between isotopes due to its high spectroscopic resolution. This frequency modulation spectroscopy technique could also be applied for the on-line monitoring of CO and CO2 using InGaAsP diode lasers operation in the 1.55 microns region and H2O in the 1.3 microns region. The existence of single mode optical fibers at the near infrared region makes it possible to combine FMS with optical fiber technology. Optical fiber FMS is particularly suitable for making point-measurements at one or more locations in the CO2 laser/catalyst system.

  1. Endocannabinoid modulation of fear responses: learning and state-dependent performance effects.

    PubMed

    Reich, C G; Mohammadi, M H; Alger, B E

    2008-09-01

    Recently, disruption of the endogenous cannabinoid (endocannabinoid, eCB) system was found to impair extinction in delay and contextual fear conditioning models. However, conditioning procedures used in that work precluded investigation of possible eCB effects on acquisition of learned fear. We therefore examined the role of eCBs in modulating fear responses using multiple-trial versions of trace (hippocampal-dependent) and delay (amygdala-dependent) Pavlovian fear conditioning. By administering the CB1 receptor antagonist AM251 (5 mg/kg, i.p) to C57/Bl/6 mice at various times, we systematically identified the stages of learning and memory (i.e. acquisition, consolidation, recall and extinction) that are modulated by eCB signaling. During tone (CS) - footshock (US) conditioning, AM251 enhanced acquisition of freezing behavior for both trace- and delay-conditioning protocols. CB1 antagonism also enhanced generalized fear (baseline freezing) and cued (CS) freezing during memory recall tests in a state-dependent manner for both trace and delay conditioned animals. Furthermore, in trace-conditioned animals, AM251 impaired extinction performance of both cued and generalized fear. CB1 antagonism did not affect short-term memory (STM) or long-term memory (LTM) consolidation processes. Together, these results suggest that during acquisition and recall of aversive learning, eCBs prevent the expression and retention of inappropriate generalized and learned responses. These findings have important implications for the therapeutic use of CB1 antagonists.

  2. Dynamic two-dimensional refractive index modulation for high performance acousto-optic deflector.

    PubMed

    Wang, Tiansi; Zhang, Chong; Aleksov, Aleksandar; Salama, Islam A; Kar, Aravinda

    2015-12-28

    The performance of an acousto-optic deflector is studied for two-dimensional refractive index that varies as periodic and sinc functions in the transverse and longitudinal directions, respectively, with respect to the direction of light propagation. Phased array piezoelectric transducers can be operated at different phase shifts to produce a two-dimensionally inhomogeneous domain of phase grating in the acousto-optic media. Also this domain can be steered at different angles by selecting the phase shift appropriately. This mechanism of dynamically tilting the refractive index-modulated domain enables adjusting the incident angle of light on the phase grating plane without moving the light source. So the Bragg angle of incidence can be always achieved at any acoustic frequency, and consequently, the deflector can operate under the Bragg diffraction condition at the optimum diffraction efficiency. Analytic solutions are obtained for the Bragg diffraction of plane waves based on the second order coupled mode theory, and the diffraction efficiency is found to be unity for optimal index modulations at certain acoustic parameters. PMID:26832030

  3. Influence of different mesh filter module configurations on effluent quality and long-term filtration performance.

    PubMed

    Loderer, Christian; Wörle, Anna; Fuchs, Werner

    2012-04-01

    Recently, a new type of wastewater treatment system became the focus of scientific research: the mesh filter activated sludge system. It is a modification of the membrane bioreactor (MBR), in which a membrane filtration process serves for sludge separation. The main difference is that a mesh filter is used instead of the membrane. The effluent is not of the same excellent quality as with membrane bioreactors due to the much lager pore sizes of the mesh. Nevertheless, it still resembles the quality of currently used standard treatment system, the activated sludge process. The new process shows high future potential as an alternative where a small footprint of these plants is required (3 times lower footprint than conventional activated sludge systems because of neglecting the secondary clarifier and reducing the biological stage). However, so far only limited information on this innovative process is available. In this study, the effect of different pore sizes and different mesh module configurations on the effluent quality was investigated varying the parameters cross-flow velocity (CFV) and flux rate. Furthermore the long-term filtration performance was studied in a pilot reactor system and results were compared to the full-scale conventional activated sludge process established at the same site. The results demonstrate that the configuration of the filter module has little impact on effluent quality and is only of importance with regard to engineering aspects. Most important for a successful operation are the hydrodynamic conditions within the filter module. The statement "the higher the pore size the higher the effluent turbidity" was verified. Excellent effluent quality with suspended solids between 5 and 15 mg L(-1) and high biological elimination rates (chemical oxygen demand (COD) 90-95%, biological oxygen demand (BOD5) 94-98%, total nitrogen (TN) 70-80%, and ammonium nitrogen (NH(4)-N) 95-99%) were achieved and also compared to those of conventional

  4. Influence of different mesh filter module configurations on effluent quality and long-term filtration performance.

    PubMed

    Loderer, Christian; Wörle, Anna; Fuchs, Werner

    2012-04-01

    Recently, a new type of wastewater treatment system became the focus of scientific research: the mesh filter activated sludge system. It is a modification of the membrane bioreactor (MBR), in which a membrane filtration process serves for sludge separation. The main difference is that a mesh filter is used instead of the membrane. The effluent is not of the same excellent quality as with membrane bioreactors due to the much lager pore sizes of the mesh. Nevertheless, it still resembles the quality of currently used standard treatment system, the activated sludge process. The new process shows high future potential as an alternative where a small footprint of these plants is required (3 times lower footprint than conventional activated sludge systems because of neglecting the secondary clarifier and reducing the biological stage). However, so far only limited information on this innovative process is available. In this study, the effect of different pore sizes and different mesh module configurations on the effluent quality was investigated varying the parameters cross-flow velocity (CFV) and flux rate. Furthermore the long-term filtration performance was studied in a pilot reactor system and results were compared to the full-scale conventional activated sludge process established at the same site. The results demonstrate that the configuration of the filter module has little impact on effluent quality and is only of importance with regard to engineering aspects. Most important for a successful operation are the hydrodynamic conditions within the filter module. The statement "the higher the pore size the higher the effluent turbidity" was verified. Excellent effluent quality with suspended solids between 5 and 15 mg L(-1) and high biological elimination rates (chemical oxygen demand (COD) 90-95%, biological oxygen demand (BOD5) 94-98%, total nitrogen (TN) 70-80%, and ammonium nitrogen (NH(4)-N) 95-99%) were achieved and also compared to those of conventional

  5. Neural variability in premotor cortex is modulated by trial history and predicts behavioral performance.

    PubMed

    Marcos, Encarni; Pani, Pierpaolo; Brunamonti, Emiliano; Deco, Gustavo; Ferraina, Stefano; Verschure, Paul

    2013-04-24

    In the study of decision making, emphasis is placed on different forms of perceptual integration, while the influence of other factors, such as memory, is ignored. In addition, it is believed that the information underlying decision making is carried in the rate of the neuronal response, while its variability is considered unspecific. Here we studied the influence of recent experience on motor decision making by analyzing the activity of neurons in the dorsal premotor area of two monkeys performing a countermanding arm task. We observe that the across-trial variability of the neural response strongly correlates with trial history-dependent changes in reaction time. Using a theoretical model of decision making, we show that a trial history-monitoring signal can explain the observed behavioral and neural modulation. Our study reveals that, in the neural processes that culminate in motor plan maturation, the evidence provided by perception and memory is reflected in mean rate and variance respectively. PMID:23622062

  6. Characteristics and performance of an intensity-modulated optically pumped magnetometer in comparison to the classical M(x) magnetometer.

    PubMed

    Schultze, Volkmar; Ijsselsteijn, Rob; Scholtes, Theo; Woetzel, Stefan; Meyer, Hans-Georg

    2012-06-18

    We compare the performance of two methods for the synchronization of the atomic spins in optically pumped magnetometers: intensity modulation of the pump light and the classical M(x) method using B(1) field modulation. Both techniques use the same set-up and measure the resulting features of the light after passing a micro-fabricated Cs cell. The intensity-modulated pumping shows several advantages: better noise-limited magnetic field sensitivity, misalignment between pumping and spin synchronization is excluded, and magnetometer arrays without any cross-talk can be easily set up.

  7. Simulated performance of the NASA 30/20 GHz test transponder using multi-H phase coded modulation

    NASA Technical Reports Server (NTRS)

    Meader, C. B.; Kwatra, S. C.; Stevens, G. H.

    1986-01-01

    The performance of a proposed NASA 30/20 GHz satellite communications system is studied for multi-h phase coded modulation (MHPM) schemes. The techniques used to model and simulate a satellite communications channel including transmitter, receiver, filters, nonlinearities, and interferers are presented. The performance of various MHPM schemes is compared for several different channel configurations. As a measure of performance, the probability of bit error vs Eb/NO is computed using a Monte Carlo simulation technique. It is found that, regardless of the channel configuration, MHPM schemes can provide power efficiency over serial minimum shift keying modulation.

  8. Speed modulation of hippocampal theta frequency correlates with spatial memory performance.

    PubMed

    Richard, Gregory R; Titiz, Ali; Tyler, Anna; Holmes, Gregory L; Scott, Rod C; Lenck-Santini, Pierre-Pascal

    2013-12-01

    Hippocampal theta rhythm is believed to play a critical role in learning and memory. In animal models of temporal lobe epilepsy (TLE), there is evidence that alterations of hippocampal theta oscillations are involved in the cognitive impairments observed in this model. However, hippocampal theta frequency and amplitude at both the local field potential (LFP) and single unit level are strongly modulated by running speed, suggesting that the integration of locomotor information into memory processes may also be critical for hippocampal processing. Here, we investigate whether hippocampal speed-theta integration influences spatial memory and whether it could account for the memory deficits observed in TLE rats. LFPs were recorded in both Control (CTR) and TLE rats as they were trained in a spatial alternation task. TLE rats required more training sessions to perform the task at CTR levels. Both theta frequency and power were significantly lower in the TLE group. In addition, speed/theta frequency correlation coefficients and regression slopes varied from session to session and were worse in TLE. Importantly, there was a strong relationship between speed/theta frequency parameters and performance. Our analyses reveal that speed/theta frequency correlation with performance cannot merely be explained by the direct influence of speed on behavior. Therefore, variations in the coordination of theta frequency with speed may participate in learning and memory processes. Impairments of this function could explain at least partially memory deficits in epilepsy.

  9. A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

    PubMed

    Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

    2015-07-29

    This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper.

  10. A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

    PubMed

    Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

    2015-01-01

    This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

  11. A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions

    PubMed Central

    Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C.

    2015-01-01

    This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

  12. Improved transmission performance of adaptively modulated optical OFDM signals over directly modulated DFB laser-based IMDD links using adaptive cyclic prefix.

    PubMed

    Giacoumidis, E; Wei, J L; Jin, X Q; Tang, J M

    2008-06-23

    The impact of Adaptive Cyclic Prefix (ACP) on the transmission performance of Adaptively Modulated Optical OFDM (AMOOFDM) is explored thoroughly in directly modulated DFB laser-based, IMDD links involving Multimode Fibres (MMFs)/Single-Mode Fibres (SMFs). Three ACP mechanisms are identified, each of which can, depending upon the link properties, affect significantly the AMOOFDM transmission performance. In comparison with AMOOFDM having a fixed cyclic prefix duration of 25%, AMOOFDM with ACP can not only improve the transmission capacity by a factor of >2 (>1.3) for >1000 m MMFs (<80 km SMFs) with 1 dB link loss margin enhancement, but also relax considerably the requirement on the DFB bandwidth. PMID:18575513

  13. Manufacturing of high performance, low cost dual mirror lamp reflector modules

    NASA Astrophysics Data System (ADS)

    Shen, Li

    The Lamp Reflector Module (LRM) is a key component in every micro display projection system, which has played a dominant role in the large-screen display market today. The goal of this research is to (1) improve the Dual Mirror prototype's light output performance, (2) investigate the underlying principles of its slow output deterioration so as to help develop effective and efficient LRM thermal management for maximized lifetime performance, and (3) improve/enable low cost mass LRM manufacturing for the projection display market. The first part of this research addresses the prototype's low output problem. More sophisticated 3D Optical Ray Tracing (ORT) models were generated to provide the output prediction depending on the arc gap, system collection etendue, etc. It was concluded that upgrading the manufacturing processes, particularly the reflector shape, surface and cold mirror coating, could effectively improve the output performance. Additionally, these theoretical models are shown to be used to design a LRM with 16% output gain for the consumer Rear Projection display market. The second part of this research focuses on the issue of lifetime performance. The electrode, arc attachment and envelope evolution were monitored by camera systems. The upgraded ORT models confirmed the arc length insensitivity property of the Dual Mirror LRM being one of the major reasons for its longer native lifetime. The third part of this research focuses on issues related to the entire LRM manufacturing. A series of quality control tools were developed to help implement manufacturing process optimization. LRMs made with the upgraded manufacturing processes showed about 25% output gain over the previous prototypes. Based on the imaging property of the Dual Mirror LRM, a lower cost lamp reflector alignment method, called cold alignment, was developed. In this method, the etendue efficiency is maintained and a slower degrading and more stable lifetime output performance are achieved

  14. Temporal modulations of agonist and antagonist muscle activities accompanying improved performance of ballistic movements.

    PubMed

    Liang, Nan; Yamashita, Takamasa; Ni, Zhen; Takahashi, Makoto; Murakami, Tsuneji; Yahagi, Susumu; Kasai, Tatsuya

    2008-02-01

    Although many studies have examined performance improvements of ballistic movement through practice, it is still unclear how performance advances while maintaining maximum velocity, and how the accompanying triphasic electromyographic (EMG) activity is modified. The present study focused on the changes in triphasic EMG activity, i.e., the first agonist burst (AG1), the second agonist burst (AG2), and the antagonist burst (ANT), that accompanied decreases in movement time and error. Twelve healthy volunteers performed 100 ballistic wrist flexion movements in ten 10-trial sessions under the instruction to "maintain maximum velocity throughout the experiment and to stop the limb at the target as fast and accurately as possible". Kinematic parameters (position and velocity) and triphasic EMG activities from the agonist (flexor carpi radialis) and antagonist (extensor carpi radialis) muscles were recorded. Comparison of the results obtained from the first and the last 10 trials, revealed that movement time, movement error, and variability of amplitudes reduced with practice, and that maximum velocity and time to maximum velocity remained constant. EMG activities showed that AG1 and AG2 durations were reduced, whereas ANT duration did not change. Additionally, ANT and AG2 latencies were reduced. Integrated EMG of AG1 was significantly reduced as well. Analysis of the alpha angle (an index of the rate of recruitment of the motoneurons) showed that there was no change in either AG1 or AG2. Correlation analysis of alpha angles between these two bursts further revealed that the close relationship of AG1 and AG2 was kept constant through practice. These findings led to the conclusion that performance improvement in ballistic movement is mainly due to the temporal modulations of agonist and antagonist muscle activities when maximum velocity is kept constant. Presumably, a specific strategy is consistently applied during practice.

  15. A high performance DAC /DDS daughter module for the RHIC LLRF platform

    SciTech Connect

    Hayes, T.; Harvey, M.; Narayan, G.; Severino, F.; Smith, K.S.; Yuan, S.

    2011-03-28

    The RHIC LLRF upgrade is a flexible, modular system. Output signals are generated by a custom designed XMC card with 4 high speed digital to analog (DAC) converters interfaced to a high performance field programmable gate array (FPGA). This paper discusses the hardware details of the XMC DAC board as well as the implementation of a low noise rf synthesizer with digital IQ modulation. This synthesizer also provides injection phase cogging and frequency hop rebucketing capabilities. A new modular RHIC LLRF system was recently designed and commissioned based on custom designed XMC cards. As part of that effort a high speed, four channel DAC board was designed. The board uses Maxim MAX5891 16 bit DACs with a maximum update rate of 600 Msps. Since this module is intended to be used for many different systems throughout the Collider Accelerator complex, it was designed to be as generic as possible. One major application of this DAC card is to implement digital synthesizers to provide drive signals to the various cavities at RHIC. Since RHIC is a storage ring with stores that typically last many hours, extremely low RF noise is a critical requirement. Synchrotron frequencies at RHIC range from a few hertz to several hundred hertz depending on the species and point in the acceleration cycle so close in phase noise is a major concern. The RHIC LLRF system uses the Update Link, a deterministic, high speed data link that broadcasts the revolution frequency and the synchronous phase angle. The digital synthesizers use this data to generate a properly phased analog drive signal. The synthesizers must also provide smooth phase shifts for cogging and support frequency shift rebucketing. One additional feature implemented in the FPGA is a digital waveform generator (WFG) that generates I and Q data pairs based on a user selected amplitude and phase profile as a function of time.

  16. A range/depth modulation transfer function (RMTF) framework for characterizing 3D imaging LADAR performance

    NASA Astrophysics Data System (ADS)

    Staple, Bevan; Earhart, R. P.; Slaymaker, Philip A.; Drouillard, Thomas F., II; Mahony, Thomas

    2005-05-01

    3D imaging LADARs have emerged as the key technology for producing high-resolution imagery of targets in 3-dimensions (X and Y spatial, and Z in the range/depth dimension). Ball Aerospace & Technologies Corp. continues to make significant investments in this technology to enable critical NASA, Department of Defense, and national security missions. As a consequence of rapid technology developments, two issues have emerged that need resolution. First, the terminology used to rate LADAR performance (e.g., range resolution) is inconsistently defined, is improperly used, and thus has become misleading. Second, the terminology does not include a metric of the system"s ability to resolve the 3D depth features of targets. These two issues create confusion when translating customer requirements into hardware. This paper presents a candidate framework for addressing these issues. To address the consistency issue, the framework utilizes only those terminologies proposed and tested by leading LADAR research and standards institutions. We also provide suggestions for strengthening these definitions by linking them to the well-known Rayleigh criterion extended into the range dimension. To address the inadequate 3D image quality metrics, the framework introduces the concept of a Range/Depth Modulation Transfer Function (RMTF). The RMTF measures the impact of the spatial frequencies of a 3D target on its measured modulation in range/depth. It is determined using a new, Range-Based, Slanted Knife-Edge test. We present simulated results for two LADAR pulse detection techniques and compare them to a baseline centroid technique. Consistency in terminology plus a 3D image quality metric enable improved system standardization.

  17. The fabrication of efficiency-improved W-series interconnect type of module by balancing the performance of single cells

    SciTech Connect

    Seo, Hyunwoong; Son, Minkyu; Hong, Jitae; Kim, Hee-Je; Lee, Dong-Yoon; An, Tae-Pung; Kim, Hyunju

    2009-12-15

    Large dye-sensitized solar cells (DSCs) are usually fabricated as module types instead of single cell types, because the overall efficiency of an area-expanded single DSC is decreased by its large surface resistances and low fill factor (FF). The general DSC module designs are the parallel grid, series interconnect, and series monolithic types. The W-series interconnect type of module has some advantages, such as its easy fabrication and simple structure. Moreover, it also avoids the reduction in the FF. However, it has an efficiency imbalance between the single cells, because of the discrepancy in their luminous intensity. Therefore, the fabrication of the W-series interconnect type of module will be cost-effective only if the problem of its efficiency imbalance is solved. In this study, the thickness of the Pt layer, which has a very high reflection rate, and that of the electrolyte layer are minimized and the transmitted light is reflected by a metallic thin film in order to increase the number of photons absorbed by the dye molecules in the module. As a result, the performance of the efficiency-balanced W-module is improved by approximately 1% as compared to that of the conventional module. (author)

  18. Inferior frontal cortex activity is modulated by reward sensitivity and performance variability.

    PubMed

    Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Costumero, Víctor; Ventura-Campos, Noelia; Bustamante, Juan Carlos; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

    2016-02-01

    High reward sensitivity has been linked with motivational and cognitive disorders related with prefrontal and striatal brain function during inhibitory control. However, few studies have analyzed the interaction among reward sensitivity, task performance and neural activity. Participants (N=57) underwent fMRI while performing a Go/No-go task with Frequent-go (77.5%), Infrequent-go (11.25%) and No-go (11.25%) stimuli. Task-associated activity was found in inhibition-related brain regions, with different activity patterns for right and left inferior frontal gyri (IFG): right IFG responded more strongly to No-go stimuli, while left IFG responded similarly to all infrequent stimuli. Reward sensitivity correlated with omission errors in Go trials and reaction time (RT) variability, and with increased activity in right and left IFG for No-go and Infrequent-go stimuli compared with Frequent-go. Bilateral IFG activity was associated with RT variability, with reward sensitivity mediating this association. These results suggest that reward sensitivity modulates behavior and brain function during executive control.

  19. The influence of flight speed on the ranging performance of bats using frequency modulated echolocation pulses

    NASA Astrophysics Data System (ADS)

    Boonman, Arjan M.; Parsons, Stuart; Jones, Gareth

    2003-01-01

    Many species of bat use ultrasonic frequency modulated (FM) pulses to measure the distance to objects by timing the emission and reception of each pulse. Echolocation is mainly used in flight. Since the flight speed of bats often exceeds 1% of the speed of sound, Doppler effects will lead to compression of the time between emission and reception as well as an elevation of the echo frequencies, resulting in a distortion of the perceived range. This paper describes the consequences of these Doppler effects on the ranging performance of bats using different pulse designs. The consequences of Doppler effects on ranging performance described in this paper assume bats to have a very accurate ranging resolution, which is feasible with a filterbank receiver. By modeling two receiver types, it was first established that the effects of Doppler compression are virtually independent of the receiver type. Then, used a cross-correlation model was used to investigate the effect of flight speed on Doppler tolerance and range-Doppler coupling separately. This paper further shows how pulse duration, bandwidth, function type, and harmonics influence Doppler tolerance and range-Doppler coupling. The influence of each signal parameter is illustrated using calls of several bat species. It is argued that range-Doppler coupling is a significant source of error in bat echolocation, and various strategies bats could employ to deal with this problem, including the use of range rate information are discussed.

  20. Performance Characteristics Of An Intensity Modulated Advanced X-Ray Source (IMAXS) For Homeland Security Applications

    NASA Astrophysics Data System (ADS)

    Langeveld, Willem G. J.; Brown, Craig; Christensen, Phil. A.; Condron, Cathie; Hernandez, Michael; Ingle, Mike; Johnson, William A.; Owen, Roger D.; Ross, Randy; Schonberg, Russell G.

    2011-06-01

    X-ray cargo inspection systems for the detection and verification of threats and contraband must address stringent, competitive performance requirements. High x-ray intensity is needed to penetrate dense cargo, while low intensity is desirable to minimize the radiation footprint, i.e. the size of the controlled area, required shielding and the dose to personnel. In a collaborative effort between HESCO/PTSE Inc., XScell Corp., Stangenes Industries, Inc. and Rapiscan Laboratories, Inc., an Intensity Modulated Advanced X-ray Source (IMAXS) was designed and produced. Cargo inspection systems utilizing such a source have been projected to achieve up to 2 inches steel-equivalent greater penetration capability, while on average producing the same or smaller radiation footprint as present fixed-intensity sources. Alternatively, the design can be used to obtain the same penetration capability as with conventional sources, but reducing the radiation footprint by about a factor of three. The key idea is to anticipate the needed intensity for each x-ray pulse by evaluating signal strength in the cargo inspection system detector array for the previous pulse. The IMAXS is therefore capable of changing intensity from one pulse to the next by an electronic signal provided by electronics inside the cargo inspection system detector array, which determine the required source intensity for the next pulse. We report on the completion of a 9 MV S-band (2998 MHz) IMAXS source and comment on its performance.

  1. The Maritime satellite communication channel - Channel model, performance of modulation and coding

    NASA Astrophysics Data System (ADS)

    Hagenauer, Joachim; Dolainsky, Frank; Lutz, Erich; Papke, Wolfgang; Schweikert, Robert

    1987-05-01

    Toward the year 2000, maritime satellite communications using the INMARSAT system will employ a second and third generation of satellites and new ship earth stations (SES). The new SES standards will use very small antennas with gains between 0 and 15 dBi. At the lower end of SES there will be no antenna stabilization. The communication channel for such small stations is described by a model including multipath fading, Doppler shift, and noise. The results of an extensive measurement program were used to determine the parameters of the channel model, which depend on antenna type and elevation angle. Analytical calculations as well as synthetic and stored channel hardware simulations have been sued to determine the performance of several modulation schemes. A complete data link using PSK modems with AFC/Costas loop, interleaving, and FEC codecs at 1.2 kbits/s, was built up around a hardware maritime channel simulator to study the performance of data transmission on the small SES maritime channel. Theoretical and measured results are given for interleaved Viterbi decoding with channel state information and Reed-Solomon codes. The measurements show that with interleaved FEC schemes, the required E(b)/N(o) for a BER of 0.00001 is in the range of 9-15 dB, and the effects of multipath fading are almost compensated for.

  2. Performance of differential amplitude pulse-position modulation with RZ coding for indoor optical wireless links

    NASA Astrophysics Data System (ADS)

    Sethakaset, Ubolthip; Gulliver, T. Aaron

    2005-02-01

    We investigate the performance of a differential amplitude pulse-position modulation with return-to-zero coding (DAPPM-RZ) over an indoor optical wireless channel. We compare the performance of DAPPM-RZ(A=2) with DAPPM(A=2), DPPM and DH-PIM. The result shows that, over a non-dispersive channel, DAPPM-RZ yields better power efficiency than DAPPM. It requires about 1.5 dB less transmit power. However, the bandwidth of DAPPM-RZ is double that of DAPPM. Compared to DPPM, the bandwidth of DAPPM-RZ is about the same as that of DPPM but DAPPM-RZ yields less power efficiency. When the number of bits/symbol(M) is above 3, the DAPPM-RZ is superior to DH-PIM_2 in terms of power efficiency but has less bandwidth efficiency. Over a dispersive channel, given the same value of M, DAPPM-RZ outperforms DPPM, DAPPM (without RZ) and DH-PIM2 when the normalized rms delay spread is high.

  3. Thermal Design and Performance results of the first High-Beta Cryo-module for HIE-ISOLDE at CERN

    NASA Astrophysics Data System (ADS)

    Valdarno, L.; Delruelle, N.; Leclercq, Y.; Parma, V.; Vandoni, G.; Williams, L.

    2015-12-01

    The High Energy and Intensity HIE-ISOLDE is a facility under construction at CERN whose target is ultimately, after the installation of six cryo-modules, to produce radioactive ion beams at 10MeV/u maximum energy in order to significantly expand the nuclear physics programme carried out by REX-ISOLDE. Since thermal control is essential to the performance of the whole cryo-module, a combination of a passive (materials, coatings, and surface finishes) and active (cryogenic loops, heaters) control has been designed to keep the cryostat operating within the allowable thermal budget. A numerical model based on Finite Element has been developed in order to generate a faithful global mapping of temperatures and heat fluxes inside the cryo-module. The numerical model, combined with the experimental results of the first test campaign, will serve as an optimization tool for the future cryo-modules in terms of improvement in the global and specific heat loads management.

  4. Improved methods for the measurement and modeling of PV module and system performance for all operating conditions

    SciTech Connect

    King, D.L.

    1995-11-01

    The objective of this work was to develop improved performance model for modules and systems for for all operating conditions for use in module specifications, system and BOS component design, and system rating or monitoring. The approach taken was to identify and quantify the influence of dominant factors of solar irradiance, cell temperature, angle-of-incidence; and solar spectrum; use outdoor test procedures to separate the effects of electrical, thermal, and optical performance; use fundamental cell characteristics to improve analysis; and combine factors in simple model using the common variables.

  5. Investigation of the Performance of Commercial Photovoltaic Modules under Tropical Conditions

    NASA Astrophysics Data System (ADS)

    Reindl, Thomas; Ouyang, Jieer; Myint Khaing, Aung; Ding, Kun; Khoo, Yong Sheng; Walsh, Timothy M.; Aberle, Armin G.

    2012-10-01

    The tropical regions will see an increasing share of solar photovoltaic (PV) applications. This paper therefore analyses the irradiance distribution in tropical Singapore and then experimentally determines the dependence of the PV efficiency on irradiance level, for nine different commercially available PV module technologies. For several of the PV module technologies, we also determine the dependence of the temperature coefficient of the modules' maximum power on the irradiance level. A full year of outdoor module testing data in Singapore show that the irradiance distribution has two energy peaks, one at around 400 W·m-2 and the second at around 850 W·m-2. Most PV technologies cannot fully convert the second peak due to the fact that, in Singapore, high light intensities are always associated with higher module temperatures, which in turn reduces the module efficiencies.

  6. Modeling and Validation of Performance Limitations for the Optimal Design of Interferometric and Intensity-Modulated Fiber Optic Displacement Sensors

    SciTech Connect

    Moro, Erik A.

    2012-06-07

    interferometric sensor depends on an appropriate performance function (e.g., desired displacement range, accuracy, robustness, etc.). In this dissertation, the performance limitations of a bundled differential intensity-modulated displacement sensor are analyzed, where the bundling configuration has been designed to optimize performance. The performance limitations of a white light Fabry-Perot displacement sensor are also analyzed. Both these sensors are non-contacting, but they have access to different regions of the performance-space. Further, both these sensors have different degrees of sensitivity to experimental uncertainty. Made in conjunction with careful analysis, the decision of which sensor to deploy need not be an uninformed one.

  7. The Self-Pleasantness Judgment Modulates the Encoding Performance and the Default Mode Network Activity.

    PubMed

    Perrone-Bertolotti, Marcela; Cerles, Melanie; Ramdeen, Kylee T; Boudiaf, Naila; Pichat, Cedric; Hot, Pascal; Baciu, Monica

    2016-01-01

    In this functional magnetic resonance imaging (fMRI) study, we evaluated the effect of self-relevance on cerebral activity and behavioral performance during an incidental encoding task. Recent findings suggest that pleasantness judgments reliably induce self-oriented (internal) thoughts and increase default mode network (DMN) activity. We hypothesized that this increase in DMN activity would relate to increased memory recognition for pleasantly-judged stimuli (which depend on internally-oriented attention) but decreased recognition for unpleasantly-judged items (which depend on externally-oriented attention). To test this hypothesis, brain activity was recorded from 21 healthy participants while they performed a pleasantness judgment requiring them to rate visual stimuli as pleasant or unpleasant. One hour later, participants performed a surprise memory recognition test outside of the scanner. Thus, we were able to evaluate the effects of pleasant and unpleasant judgments on cerebral activity and incidental encoding. The behavioral results showed that memory recognition was better for items rated as pleasant than items rated as unpleasant. The whole brain analysis indicated that successful encoding (SE) activates the inferior frontal and lateral temporal cortices, whereas unsuccessful encoding (UE) recruits two key medial posterior DMN regions, the posterior cingulate cortex (PCC) and precuneus (PCU). A region of interest (ROI) analysis including classic DMN areas, revealed significantly greater involvement of the medial prefrontal cortex (mPFC) in pleasant compared to unpleasant judgments, suggesting this region's involvement in self-referential (i.e., internal) processing. This area may be responsible for the greater recognition performance seen for pleasant stimuli. Furthermore, a significant interaction between the encoding performance (successful vs. unsuccessful) and pleasantness was observed for the PCC, PCU and inferior frontal gyrus (IFG). Overall, our

  8. Ocean acidification modulates expression of genes and physiological performance of a marine diatom

    NASA Astrophysics Data System (ADS)

    Li, Y.; Zhuang, S.; Wu, Y.; Ren, H.; Cheng, F.; Lin, X.; Wang, K.; Beardall, J.; Gao, K.

    2015-09-01

    Ocean Acidification (OA) is known to affect various aspects of the physiological performance of diatoms, but there is little information on the underlining molecular mechanisms involved. Here, we show that in the model diatom Phaeodactylum tricornutum expression of the genes related to light harvesting, carbon acquisition and carboxylation, nitrite assimilation and ATP synthesis are modulated by OA. Growth and photosynthetic carbon fixation were enhanced by elevated CO2 (1000 μatm) under both constant indoor and fluctuating outdoor light regimes. The genetic expression of nitrite reductase (NiR) was up-regulated by OA regardless of light levels and/or regimes. The transcriptional expression of fucoxanthin chlorophyll a/c protein (lhcf type (FCP)) and mitochondrial ATP synthase (mtATP synthase) genes were also enhanced by OA, but only under high light intensity. OA treatment decreased the expression of β-carbonic anhydrase (β-CA) along with down-regulation of CO2 concentrating mechanisms (CCMs). Additionally, the genes for these proteins (NiR, FCP, mtATP synthase, β-CA) showed diel expressions either under constant indoor light or fluctuating sunlight. Thus, OA enhanced photosynthetic and growth rates by stimulating nitrogen assimilation and indirectly by down-regulating the energy-costly inorganic carbon acquisition process.

  9. Timing performance of phased-locked loops in optical pulse position modulation communication systems

    NASA Technical Reports Server (NTRS)

    Lafaw, D. A.; Gardner, C. S.

    1984-01-01

    An optical digital communication system requires that an accurate clock signal be available at the receiver for proper synchronization with the transmitted signal. Phase synchronization is especially critical in M-ary pulse position modulation (PPM) systems where the optimum decision scheme is an energy detector which compares the energy in each of M time slots to decide which of M possible words was sent. Timing errors cause energy spillover into adjacent time slots (a form of intersymbol interference) so that only a portion of the signal energy may be attributed to the correct time slot. This effect decreases the effective signal, increases the effective noise, and increases the probability of error. A timing subsystem for a satellite-to-satellite optical PPM communication link is simulated. The receiver employs direct photodetection, preprocessing of the detected signal, and a phase-locked loop for timing synchronization. The variance of the relative phase error is examined under varying signal strength conditions as an indication of loop performance, and simulation results are compared to theoretical calculations.

  10. Module performance and failure analysis area: Flat-plate solar array project

    NASA Technical Reports Server (NTRS)

    Tornstrom, E.

    1984-01-01

    A redesign of the initial (Group I) Mobile Solar Block V module was done and documented. Manufacturing experience and accelerated test data from Group I formed the basis for the redesign. Ten Block V Group II modules were submitted for evaluation and the results are presented.

  11. Engine Performance (Section B: Fuel and Exhaust Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    ERIC Educational Resources Information Center

    Rains, Larry

    This module is the third of nine modules in the competency-based Missouri Auto Mechanics Curriculum Guide. Six units cover: fuel supply systems; carburetion; carburetor service; gasoline engine electronic fuel injection; diesel fuel injection; and exhaust systems and turbochargers. Introductory materials include a competency profile and…

  12. Module 2--Learning Culture. School Improvement Specialist Training Materials: Performance Standards, Improving Schools, and Literature Review

    ERIC Educational Resources Information Center

    Appalachia Educational Laboratory at Edvantia (NJ1), 2005

    2005-01-01

    The School Improvement Specialist Project prepared seven modules. School improvement specialists, as defined by the Appalachia Educational Laboratory at Edvantia, are change agents who work with schools to help them improve in the following areas so as to increase student achievement. These modules are intended to provide training materials for…

  13. In-Flight Performance of the Polarization Modulator in the CLASP Rocket Experiment

    NASA Technical Reports Server (NTRS)

    Ishikawa, Shin-nosuke; Shimizu, Toshifumi; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Giono, Gabriel; Beabout, Dyana L.; Beabout, Brent L.; Nakayama, Satoshi; Tajima, Takao

    2016-01-01

    We developed a polarization modulation unit (PMU), a motor system to rotate a waveplate continuously. In polarization measurements, the continuous rotating waveplate is an important element as well as a polarization analyzer to record the incident polarization in a time series of camera exposures. The control logic of PMU was originally developed for the next Japanese solar observation satellite SOLAR-C by the SOLAR-C working group. We applied this PMU for the Chromospheric Lyman-alpha SpectroPolarimeter (CLASP). CLASP is a sounding rocket experiment to observe the linear polarization of the Lyman-alpha emission (121.6 nm vacuum ultraviolet) from the upper chromosphere and transition region of the Sun with a high polarization sensitivity of 0.1 % for the first time and investigate their vector magnetic field by the Hanle effect. The driver circuit was developed to optimize the rotation for the CLASP waveplate (12.5 rotations per minute). Rotation non-uniformity of the waveplate causes error in the polarization degree (i.e. scale error) and crosstalk between Stokes components. We confirmed that PMU has superior rotation uniformity in the ground test and the scale error and crosstalk of Stokes Q and U are less than 0.01 %. After PMU was attached to the CLASP instrument, we performed vibration tests and confirmed all PMU functions performance including rotation uniformity did not change. CLASP was successfully launched on September 3, 2015, and PMU functioned well as designed. PMU achieved a good rotation uniformity, and the high precision polarization measurement of CLASP was successfully achieved.

  14. Performance of the prototype module of the GlueX electromagnetic barrel calorimeter

    SciTech Connect

    Leverington, Blake; Lolos, George; Papandreou, Zisis; Hakobyan, Rafael; Huber, Garth; Janzen, Kathryn; Semenov, Andrei; Scott, Eric; Shepherd, Matthew; Carman, Daniel; Lawrence, David; Smith, Elton; Taylor, Simon; Wolin, Elliott; Klein, Franz; Santoro, Joseph; Sober, Daniel; Kourkoumeli, Christina

    2008-11-01

    A photon beam test of the 4 m long prototype lead/scintillating-fibre module for the GlueX electromagnetic barrel calorimeter was carried out in Hall B at the Thomas Jefferson National Accelerator Facility with the objective of measuring the energy and timing resolutions of the module as well as the number of photoelectrons generated. Data were collected over an energy range of 150 - â 650 MeV at multiple positions and angles along the module. Details of the analysis at the centre of and perpendicular to the module are shown herein; the results are View the MathML source, View the MathML source ps, and 660 photoelectrons for 1 GeV at each end of the module.

  15. Self-Assessment of Practice Performance: Development of the ABIM Practice Improvement Module (PIM[superscript SM])

    ERIC Educational Resources Information Center

    Duffy, F. Daniel; Lynn, Lorna A.; Didura, Halyna; Hess, Brian; Caverzagie, Kelly; Grosso, Louis; Lipner, Rebecca A.; Holmboe, Eric S.

    2008-01-01

    Background: Quality measurement and improvement in practice are requirements for Maintenance of Certification by the American Board of Medical Specialties boards and a component of many pay for performance programs. Objective: To describe the development of the American Board of Internal Medicine (ABIM) Practice Improvement Module (PIM[superscript…

  16. Can Teaching Be Evaluated through Reflection on Student Performance in Continuous Assessment? A Case Study of Practical Engineering Modules

    ERIC Educational Resources Information Center

    McNabola, Aonghus; O'Farrell, Ciara

    2015-01-01

    Research and practice is presented on the use of student assessments as part of reflective practice to evaluate teaching. Case studies are presented in the delivery of Engineering modules across a number of years at undergraduate and postgraduate levels. Both student performance in continuous assessment and student feedback on assessments…

  17. High Performance Packaging Solutions for Low Cost, Reliable PV Modules: Final Subcontract Report, 26 May 2005 - 30 November 2008

    SciTech Connect

    Keotla, B. M.; Marinik, B. J.

    2009-06-01

    During this research effort, Dow Corning Corporation has addressed the PV manufacturing goals of: (i) improving PV manufacturing processes and equipment; (ii) accelerating manufacturing cost reductions of PV modules; (iii) increasing commercial product performance and reliability; and (iv) scaling up U.S. manufacturing capacity.

  18. MSFC Skylab airlock module, volume 2. [systems design and performance, systems support activity, and reliability and safety programs

    NASA Technical Reports Server (NTRS)

    1974-01-01

    System design and performance of the Skylab Airlock Module and Payload Shroud are presented for the communication and caution and warning systems. Crew station and storage, crew trainers, experiments, ground support equipment, and system support activities are also reviewed. Other areas documented include the reliability and safety programs, test philosophy, engineering project management, and mission operations support.

  19. Method to improve the performance of the optical modulation format identification system based on asynchronous amplitude histogram

    NASA Astrophysics Data System (ADS)

    Cui, Sheng; He, Sheng; Shang, Jin; Ke, Changjian; Fu, Songnian; Liu, Deming

    2015-06-01

    A method to improve the performance of the asynchronous amplitude histogram (AAH) based optical modulation format identification system is proposed. It is demonstrated that with additional static dispersion compensation modules (SDCMs), polarization and non-polarization multiplexed (PM/NPM) signals can be distinguished simply from the AAH peak position difference, while the stringent chromatic dispersion limit imposed on the MFI method can be expanded up to desired values by selectively enabling the SDCMs to minimize the width to area ratio (WAR) of the AAH. Numerical simulations and experiments are carried out to demonstrate the effectiveness of this method.

  20. Performance of first-year health sciences students in a large, diverse, multidisciplinary, first-semester, physiology service module.

    PubMed

    Higgins-Opitz, Susan B; Tufts, Mark

    2014-06-01

    Health Science students at the University of KwaZulu-Natal perform better in their professional modules compared with their physiology modules. The pass rates of physiology service modules have steadily declined over the years. While a system is in place to identify "at-risk" students, it is only activated after the first semester. As a result, it is only from the second semester of their first year studies onward that at-risk students can be formally assisted. The challenge is thus to devise an appropriate strategy to identify struggling students earlier in the semester. Using questionnaires, students were asked about attendance, financing of their studies, and relevance of physiology. After the first class test, failing students were invited to complete a second questionnaire. In addition, demographic data were also collected and analyzed. Correlation analyses were undertaken of performance indicators based on the demographical data collected. The 2011 class comprised mainly sport science students (57%). The pass rate of sport science students was lower than the pass rates of other students (42% vs. 70%, P < 0.001). Most students were positive about physiology and recognized its relevance. Key issues identified were problems understanding concepts and terminology, poor study environment and skills, and lack of matriculation biology. The results of the first class test and final module marks correlated well. It is clear from this study that student performance in the first class test is a valuable tool to identify struggling students and that appropriate testing should be held as early as possible.

  1. Enhancing the performance of fluorescence emission difference microscopy using beam modulation

    NASA Astrophysics Data System (ADS)

    Li, Shuai; Kuang, Cuifang; Hao, Xiang; Wang, Yifan; Ge, Jianhong; Liu, Xu

    2013-12-01

    Fluorescence emission difference microscopy (FED) has been proved to be an effective method to break the diffraction barrier which had restricted the spatial resolution of optical microscopy in the far-field for a long time. In this paper, we theoretically demonstrate that the attainable resolution of FED can be further enhanced by using beam modulation. By applying beam shape modulating, polarization state modulating, phase encoding and beam blocking to the illumination beams in the process of FED imaging, we optimize the size of the corresponding PSFs and thus improve the resolving ability of FED. The simulation tests demonstrate that in the optimal case after beam modulation, the resolution of FED can be enhanced by a factor of 26% compared with a conventional one.

  2. Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module

    SciTech Connect

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Cowley, S.; Kayes, B.; Kurtz, S.

    2013-06-01

    We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

  3. Optimized MCT IR-modules for high-performance imaging applications

    NASA Astrophysics Data System (ADS)

    Breiter, R.; Eich, D.; Figgemeier, H.; Lutz, H.; Wendler, J.; Rühlich, I.; Rutzinger, S.; Schallenberg, T.

    2014-06-01

    In today's typical military operations situational awareness is a key element for mission success. In contrast to what is known from conventional warfare with typical targets such as tanks, asymmetric scenarios now dominate military operations. These scenarios require improved identification capabilities, for example the assessment of threat levels posed by personnel targets. Also, it is vital to identify and reliably distinguish between combatants, non-combatants and friendly forces. To satisfy these requirements, high-definition (HD) large format systems are well suited due to their high spatial and thermal resolution combined with high contrast. Typical applications are sights for long-range surveillance, targeting and reconnaissance platforms as well as rotorcraft pilotage sight systems. In 2012 AIM presented first prototypes of large format detectors with 1280 × 1024 elements in a 15μm pitch for both spectral bands MWIR and LWIR. The modular design allows integration of different cooler types, like AIM's split linear coolers SX095 or SX040 or rotary integral types depending whatever fits best to the application. Large format FPAs have been fabricated using liquid phase epitaxy (LPE) or molecular beam epitaxy (MBE) grown MCT. To offer high resolution in a more compact configuration AIM started the development of a 1024 × 768 10μm pitch IRmodule. Keeping electro/optical performance is achieved by a higher specific charge handling capacity of the readout integrated circuit (ROIC) in a 0.18μm Si CMOS technology. The FPA size fits to a dewar cooler configuration used for 640 × 512 15μm pitch modules.

  4. Estimating Parameters for the PVsyst Version 6 Photovoltaic Module Performance Model

    SciTech Connect

    Hansen, Clifford

    2015-10-01

    We present an algorithm to determine parameters for the photovoltaic module perf ormance model encoded in the software package PVsyst(TM) version 6. Our method operates on current - voltage (I - V) measured over a range of irradiance and temperature conditions. We describe the method and illustrate its steps using data for a 36 cell crystalli ne silicon module. We qualitatively compare our method with one other technique for estimating parameters for the PVsyst(TM) version 6 model .

  5. High-performance illumination module of RGB LEDs pico-projector with dual double side micro lens array

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chieh; Wu, Hsin-Chieh; Wu, Moint-Learn; Cheng, Yuan-Chieh; Hsu, Wei-Yao

    2012-10-01

    In this research, we propose a high performance non-image illumination module of pico-projector which includes light source, collimator and liquid crystal on silicon (LCoS) panel. The light source is RGB LED. The collimator consists of two glass collimator lenses and two double sides micro lens array (MLA) for light homogenizer. MLAs play a critical role in the LED illumination module. Dual double-side MLAs have been adopted for the homogenizer to satisfy the numerical aperture in the optical design. The good uniformity and high accuracy MLA structure was generated by ultra precision diamond shaping method and the MLA plate is subsequently fabricated by injection molding. Finally, a non-image illumination module with power efficiency 30.87 lm/w and uniformity of 56% on LCoS panel in a very compact size, less than 1.6 cm3 in volume, has been developed.

  6. High-performance GaAs/AlGaAs optical phase modulators for microwave/photonic integrated circuits

    SciTech Connect

    Hietala, V.M.; Kravitz, S.H.; Armendariz, M.G.; Vawter, G.A.; Carson, R.F.; Leibenguth, R.E.

    1993-12-31

    High-speed high-performance optical phase modulators are being developed for use in a coherent Photonic Integrated Circuit (PIC) technology. These phase modulators are the critical component of a PIC program at Sandia National Laboratories targeted for microwave/millimeter-wave signal processing and control including phased-array antenna control. The primary design goals for these modulators are amenability for integration into PICs, high ``figure of merit`` (FOM -- phase shift per unit length-voltage), and large bandwidths allowing for operation at millimeter wave frequencies. Depletion-edge-translation optical phase modulators (GaAs/AlGaAs based) have been selected as the device technology of choice due to their high FOM (>60{degree}/V{center_dot}mm @ 1.3 {mu}m). These modulators unfortunately suffer from a large terminal capacitance which greatly limits speed. To overcome this problem, a distributed electrode design based on the use of slow-wave coplanar strips has been developed. Device design and measurements are presented in this paper.

  7. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation: Functional modules F1-F8

    SciTech Connect

    1997-03-01

    This Manual represents Revision 5 of the user documentation for the modular code system referred to as SCALE. The history of the SCALE code system dates back to 1969 when the current Computational Physics and Engineering Division at Oak Ridge National Laboratory (ORNL) began providing the transportation package certification staff at the U.S. Atomic Energy Commission with computational support in the use of the new KENO code for performing criticality safety assessments with the statistical Monte Carlo method. From 1969 to 1976 the certification staff relied on the ORNL staff to assist them in the correct use of codes and data for criticality, shielding, and heat transfer analyses of transportation packages. However, the certification staff learned that, with only occasional use of the codes, it was difficult to become proficient in performing the calculations often needed for an independent safety review. Thus, shortly after the move of the certification staff to the U.S. Nuclear Regulatory Commission (NRC), the NRC staff proposed the development of an easy-to-use analysis system that provided the technical capabilities of the individual modules with which they were familiar. With this proposal, the concept of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system was born. This volume consists of the section of the manual dealing with eight of the functional modules in the code. Those are: BONAMI - resonance self-shielding by the Bondarenko method; NITAWL-II - SCALE system module for performing resonance shielding and working library production; XSDRNPM - a one-dimensional discrete-ordinates code for transport analysis; XSDOSE - a module for calculating fluxes and dose rates at points outside a shield; KENO IV/S - an improved monte carlo criticality program; COUPLE; ORIGEN-S - SCALE system module to calculate fuel depletion, actinide transmutation, fission product buildup and decay, and associated radiation source terms; ICE.

  8. The design and performance of a point-focus concentrator module

    NASA Astrophysics Data System (ADS)

    Shepard, N. F., Jr.; Chan, T. S.

    Design parameters of a passively-cooled point-focus photovoltaic concentrator module for use in remote, stand-alone, or intermediate load center applications are presented. A solar cell mount assembly using a direct-bonded copper-on-aluminum insulator is employed to provide the required electrical isolation with a less than 0.2 C/W thermal resistance between the solar cell junction and the interface with the module baseplate. The cell mount is bolted to the module baseplate at the focus of a Fresnel lens parquet, which is a laminate of 25 individual 170 mm square compression molded acrylic lenses. Thermal analysis reveals that a 1.5 mm thick aluminum plate is the most effective for heat dissipation, and a cell temperature of 53 C for a direct normal insolation of 100 mW/sq cm can be expected. Prototype module test results demonstrate a 12.4% efficiency, and indicate a 6.5 W power increase over a flat-panel module.

  9. Performance of 3-sun mirror modules on sun tracking carousels on flat roof buildings

    NASA Astrophysics Data System (ADS)

    Fraas, Lewis; Avery, James; Minkin, Leonid; Maxey, Curt; Gehl, Tony; Hurt, Rick; Boehm, Robert

    2008-08-01

    Commercial buildings represent a near term market for cost competitive solar electric power provided installation costs and solar photovoltaic module costs can be reduced. JX Crystals has developed a carousel sun tracker that is prefabricated and can easily be deployed on building flat roof tops without roof penetration. JX Crystals is also developing 3-sun PV mirror modules where less expensive mirrors are substituted for two-thirds of the expensive single crystal silicon solar cell surface area. Carousels each with four 3-sun modules have been set up at two sites, specifically at Oak Ridge National Lab and at the University of Nevada in Las Vegas. The test results for these systems are presented.

  10. Employing split-band technique and Fabry Perot etalon filter to improve directly modulated fiber optical CATV system performances

    NASA Astrophysics Data System (ADS)

    Lu, Hai-Han; Patra, Ardhendu Sekhar; Wu, Hsiao-Wen; Tzeng, Shah-Jye; Ho, Wen-Jeng; Yee, Hoshin

    2008-07-01

    We proposed and demonstrated a directly modulated NTSC 77-channel fiber optical CATV transport system using split-band technique at the transmitting site and Fabry-Perot (FP) etalon filter at the receiving site to improve system performance. Good performance of carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple beat (CTB) were obtained in our proposed systems over a 100-km standard single-mode fiber (SMF) transmission. Employing a FP etalon filter in fiber optical CATV transport systems is useful in real network, as it is simple, passive, and potentially low cost. This proposed system reveals an outstanding one with simpler and more economic advantages than that of externally modulated transport system.

  11. Capacitance Measurement with a Sigma Delta Converter for 3D Electrical Capacitance Tomography

    NASA Technical Reports Server (NTRS)

    Nurge, Mark

    2005-01-01

    This paper will explore suitability of a newly available capacitance to digital converter for use in a 3D Electrical Capacitance Tomography system. A switch design is presented along with circuitry needed to extend the range of the capacitance to digital converter. Results are then discussed for a 15+ hour drift and noise test.

  12. The braking performance of a vehicle anti-lock brake system featuring an electro-rheological valve pressure modulator

    NASA Astrophysics Data System (ADS)

    Choi, Seung-Bok; Sung, Kum-Gil; Cho, Myung-Soo; Lee, Yang-Sub

    2007-08-01

    This paper presents the braking performances of a vehicle anti-lock brake system (ABS) featuring an electro-rheological (ER) valve pressure modulator. As a first step, the principal design parameters of the ER valve and hydraulic booster are appropriately determined by considering the Bingham property of the ER fluid and the braking pressure variation during the ABS operation. An ER fluid composed of chemically treated starch particles and silicone oil is used. An electrically controllable pressure modulator is then constructed and its pressure controllability is empirically evaluated. Subsequently, a quarter-car wheel slip model is established and integrated with the governing equation of the pressure modulator. A sliding mode controller for slip rate control is designed and implemented via the hardware-in-the-loop simulation (HILS). In order to demonstrate the superior braking performance of the proposed ABS, a full car model is derived and a sliding mode controller is formulated to achieve the desired yaw rate. The braking performances in terms of braking distance and step input steering are evaluated and presented in time domain through full car simulations.

  13. Electro-optic modulator with exceptional power-size performance enabled by transparent conducting electrodes.

    PubMed

    Yi, Fei; Ou, Fang; Liu, Boyang; Huang, Yingyan; Ho, Seng-Tiong; Wang, Yiliang; Liu, Jun; Marks, Tobin J; Huang, Su; Luo, Jingdong; Jen, Alex K-Y; Dinu, Raluca; Jin, Dan

    2010-03-29

    An EO phase modulator having transparent conducting oxide electrodes and an inverted rib waveguide structure is demonstrated. This new modulator geometry employs an EO polymer having an in-device r33 = 60pm/V. The measured half-wave voltage Vpi of these devices ranges from 5.3V to 11.2V for 3.8 and 1.5 mm long devices, respectively. The lowest VpiL figure-of-merit corresponds to 0.6V-cm (7.2mW-cm(2) of power length product) in a dual-drive configuration. The trade-off between Vpi, insertion loss and modulation bandwidth is systematically analyzed. An optimized high-speed structure is proposed, with numerical simulation showing that this new structure and an in-device r33 = 150pm/V, can achieve Vpi = 0.5V in a 5mm long active length with dual drive operation. The insertion loss is targeted at 6dB, and a 3dB optical modulation bandwidth can reach > 40GHz.

  14. To Help Children Read: Mastery Performance Modules for Teachers in Training.

    ERIC Educational Resources Information Center

    May, Frank B.

    This book is designed for both preservice and inservice teachers of reading. The contents are divided into nine modules: (1) "Making Your Plans for Reading Instruction," (2) "Helping Children Develop Skill in Phonic Analysis," (3) "Using Principles of Learning to Teach Reading Effectively," (4) "Helping Children Develop Other Word Recognition…

  15. Analysis of Performance for 100 Gbit/s Dual-Polarization QPSK Modulation Format System

    NASA Astrophysics Data System (ADS)

    Li, Li; Xiao-bo, Guo; Jing, Li

    2016-03-01

    This article introduces modulation technology, coherent reception technology, the overall design and other key issues for 100 Gbit/s dual-polarization quadrature phase shift keying (DP-QPSK) modulation. Using the technologies based on digital signal processing (DSP), it realizes the long-range transmissions of 100 Gbit/s optical systems to achieve optical signal dispersion compensation, polarized solution reuse and phase estimation. The effect of this scheme is verified with OptiSystem, and the simulation results indicate, with the help of DSP module for processing of the received signal, that the last constellation is ideal and the data transmission error rate is less than 1.3 e-4. The scheme is implemented simply and has high reliability, and it also has reference significance for the optimization of coherent optical detection hardware. As they feature in high spectrum efficiency and large dispersion and PMD tolerances, the DP-QPSK modulation can improve the line efficiency, and maximize the spectral efficiency of the dense wavelength division multiplexing systems. The quality of eye diagram is high, which is clean and has decent open degree.

  16. Feedback-Related ERP Components Are Modulated by Social Distance during Non-Contingent Evaluation of Someone Else's Performance.

    PubMed

    Villuendas-González, Erwin Rogelio; González-Garrido, Andrés Antonio

    2016-01-01

    Performance monitoring depends on cortical structures that are also activated in vicarious monitoring. While many experiments have shown that vicarious and on-line monitoring have a similar basis, most such experiments have focused on simple tasks. In order to assess the effect of non-contingent feedback on vicarious monitoring, 23 young volunteer adults were evaluated: in one session, they performed a rule-based category formation task, receiving no feedback on their performance. In a second session, Event Related Potentials (ERPs) were obtained while participants passively reviewed performances attributed to themselves and peers they had previously rated as either socially close or distant. Feedback Related Negativity (FRN) and Feedback Related P300 (fP300) components were analyzed with respect to feedback valence and agent. Results show that both components can be elicited through non-contingent feedback related to prior performance. In addition, FRN waves are modulated by the valence of the feedback, and fP300 is modulated by the agent to whom performance feedback is attributed. This experiment constitutes a novel approach to the evaluation of ERP correlates of vicarious monitoring through non-contingent feedback and its relations to empathy processing.

  17. Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Fan, Libo; Guo, Qiuquan; Shi, Hongcai; Wang, Liwen; Liu, Yujian; Li, Ming; Zhang, Chunli; Yang, Jun; Zheng, Zhi

    2016-09-01

    Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (J p) with time (t), dark current-voltage (I-V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I-V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research.

  18. Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance.

    PubMed

    Wang, Peng; Fan, Libo; Guo, Qiuquan; Shi, Hongcai; Wang, Liwen; Liu, Yujian; Li, Ming; Zhang, Chunli; Yang, Jun; Zheng, Zhi

    2016-09-01

    Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (J p) with time (t), dark current-voltage (I-V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I-V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research. PMID:27455067

  19. Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Fan, Libo; Guo, Qiuquan; Shi, Hongcai; Wang, Liwen; Liu, Yujian; Li, Ming; Zhang, Chunli; Yang, Jun; Zheng, Zhi

    2016-09-01

    Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (J p) with time (t), dark current–voltage (I–V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I–V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research.

  20. Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance.

    PubMed

    Wang, Peng; Fan, Libo; Guo, Qiuquan; Shi, Hongcai; Wang, Liwen; Liu, Yujian; Li, Ming; Zhang, Chunli; Yang, Jun; Zheng, Zhi

    2016-09-01

    Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (J p) with time (t), dark current-voltage (I-V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I-V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research.

  1. Performance evaluation of modulation and multiple access schemes in ultraviolet optical wireless connections for two atmosphere thickness cases.

    PubMed

    Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris

    2016-08-01

    The exploitation of optical wireless communication channels in a non-line-of-sight regime is studied for point-to-point and networking configurations considering the use of light-emitting diodes. Two environments with different scattering center densities are considered, assuming operation at 265 nm. The bit error rate performance of both pulsed and multicarrier modulation schemes is examined, using numerical approaches. In the networking scenario, a central node only receives data, one node transmits useful data, and the rest of them act as interferers. The performance of the desirable node's transmissions is evaluated. The access to the medium is controlled by a code division multiple access scheme. PMID:27505663

  2. Performance evaluation of modulation and multiple access schemes in ultraviolet optical wireless connections for two atmosphere thickness cases.

    PubMed

    Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris

    2016-08-01

    The exploitation of optical wireless communication channels in a non-line-of-sight regime is studied for point-to-point and networking configurations considering the use of light-emitting diodes. Two environments with different scattering center densities are considered, assuming operation at 265 nm. The bit error rate performance of both pulsed and multicarrier modulation schemes is examined, using numerical approaches. In the networking scenario, a central node only receives data, one node transmits useful data, and the rest of them act as interferers. The performance of the desirable node's transmissions is evaluated. The access to the medium is controlled by a code division multiple access scheme.

  3. Performance of first-year health sciences students in a large, diverse, multidisciplinary, first-semester, physiology service module

    PubMed Central

    Tufts, Mark

    2014-01-01

    Health Science students at the University of KwaZulu-Natal perform better in their professional modules compared with their physiology modules. The pass rates of physiology service modules have steadily declined over the years. While a system is in place to identify “at-risk” students, it is only activated after the first semester. As a result, it is only from the second semester of their first year studies onward that at-risk students can be formally assisted. The challenge is thus to devise an appropriate strategy to identify struggling students earlier in the semester. Using questionnaires, students were asked about attendance, financing of their studies, and relevance of physiology. After the first class test, failing students were invited to complete a second questionnaire. In addition, demographic data were also collected and analyzed. Correlation analyses were undertaken of performance indicators based on the demographical data collected. The 2011 class comprised mainly sport science students (57%). The pass rate of sport science students was lower than the pass rates of other students (42% vs. 70%, P < 0.001). Most students were positive about physiology and recognized its relevance. Key issues identified were problems understanding concepts and terminology, poor study environment and skills, and lack of matriculation biology. The results of the first class test and final module marks correlated well. It is clear from this study that student performance in the first class test is a valuable tool to identify struggling students and that appropriate testing should be held as early as possible. PMID:24913452

  4. Performance evaluation of ePTFE and PVDF flat-sheet module direct contact membrane distillation.

    PubMed

    Chuang, Ching-Jung; Tung, Kuo-Lun; Fan, Yang-Hsiang; Ho, Chii-Dong; Huang, James

    2010-01-01

    This paper reports experiments using a flat-sheet module with 0.18 approximately 0.45 microm ePTFE (expanded polytetrafluoroethylene) and PVDF (polyvinylidene fluoride) membranes to show the effects of membrane properties, salt concentration and fluid hydrodynamics on the permeate flux and salt rejection of DCMD (direct contact membrane distillation). A theoretical prediction of the permeate flux was carried out, and was in close agreement with the experimental results. In addition, the energy integration of the process was also analyzed in order to evaluate module design to increase energy efficiency. According to the simulated results of the energy integration design, a combination of simultaneous cooling of the permeate stream and an additional heat exchanger to lower the temperature of the permeate stream not only enhances the MD flux, but also reduces energy consumption.

  5. Performance of kilowatt-class laser modules in scaling up laser produced plasma (LPP) EUV source

    NASA Astrophysics Data System (ADS)

    Ellwi, Samir; Comley, Andrew; Hay, Nick; Henderson, Ian; Brownell, Michael

    2005-05-01

    Powerlase has made significant steps forward in developing reliable and cost-effective, kilowatt-class laser modules with short pulse duration and small footprint, for use as EUV drivers. These characteristics in parallel to EUV target requirements are essential for the generation of 115W of in-band EUV power at the intermediate focus. These laser modules can be coupled to the EUV target by using our flexible spatial and temporal multiplexing approach in order to scale up the laser average power on target. The multiplexing method developed by Powerlase is modular and optimised for maximum EUV collection angle. To further this goal we are currently evaluating target materials such as xenon in various phases and forms and also have a programme in place to investigate suitable tin targets.

  6. Dynamic Circadian Modulation in a Biomathematical Model for the Effects of Sleep and Sleep Loss on Waking Neurobehavioral Performance

    PubMed Central

    McCauley, Peter; Kalachev, Leonid V.; Mollicone, Daniel J.; Banks, Siobhan; Dinges, David F.; Van Dongen, Hans P. A.

    2013-01-01

    Recent experimental observations and theoretical advances have indicated that the homeostatic equilibrium for sleep/wake regulation—and thereby sensitivity to neurobehavioral impairment from sleep loss—is modulated by prior sleep/wake history. This phenomenon was predicted by a biomathematical model developed to explain changes in neurobehavioral performance across days in laboratory studies of total sleep deprivation and sustained sleep restriction. The present paper focuses on the dynamics of neurobehavioral performance within days in this biomathematical model of fatigue. Without increasing the number of model parameters, the model was updated by incorporating time-dependence in the amplitude of the circadian modulation of performance. The updated model was calibrated using a large dataset from three laboratory experiments on psychomotor vigilance test (PVT) performance, under conditions of sleep loss and circadian misalignment; and validated using another large dataset from three different laboratory experiments. The time-dependence of circadian amplitude resulted in improved goodness-of-fit in night shift schedules, nap sleep scenarios, and recovery from prior sleep loss. The updated model predicts that the homeostatic equilibrium for sleep/wake regulation—and thus sensitivity to sleep loss—depends not only on the duration but also on the circadian timing of prior sleep. This novel theoretical insight has important implications for predicting operator alertness during work schedules involving circadian misalignment such as night shift work. Citation: McCauley P; Kalachev LV; Mollicone DJ; Banks S; Dinges DF; Van Dongen HPA. Dynamic circadian modulation in a biomathematical model for the effects of sleep and sleep loss on waking neurobehavioral performance. SLEEP 2013;36(12):1987-1997. PMID:24293775

  7. Experimental Performance of a Single-Mode Ytterbium-doped Fiber Ring Laser with Intracavity Modulator

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Camp, Jordan

    2012-01-01

    We have developed a linearly polarized Ytterbium-doped fiber ring laser with a single longitudinal mode output at 1064 run. A fiber-coupled intracavity phase modulator ensured mode-hop free operation and allowed fast frequency tuning. The fiber laser was locked with high stability to an iodine-stabilized laser, showing a frequency noise suppression of a factor approx 10 (exp 5) at 1 mHz

  8. Latest ATIR Module Performance And A Vision Of Things To Come

    NASA Astrophysics Data System (ADS)

    Grimmer, Chris; Ghosh, Shondip; Schultz, David; Mack, Hunter; Rakestraw, Ken

    2011-12-01

    While the motivation for concentrating photovoltaics (CPV) is simple, namely the ability to scale production while minimizing capital expenditure and at the same time decrease per unit costs by replacing semiconductor with commodity materials, large scale adoption of CPV lags. This resistance to adoption is due in part to high system costs, insufficient optical efficiency, unproven reliability, and a general misfit of CPV designs with existing system-level infrastructure. The use of aggregated total internal reflection (ATIR) as the optical mechanism around which one constructs a CPV module provides a unique opportunity to overcome these challenges. We present here the module-level results of a first series of prototypes that not only achieves competitive optical efficiencies, but does so in a more traditional flat form factor, with acceptance angles that allow conversion of a large percentage of the diffuse resource (±2.9° daily, ±28.0° seasonal, at 95% of peak power), and uniform light flux on the cell (1.6:1, peak to average). Additionally, we present our next generation module design, developed with the directive of addressing long-term reliability and manufacturing costs at scale.

  9. Dynamic circadian modulation in a biomathematical model for the effects of sleep and sleep loss on waking neurobehavioral performance.

    PubMed

    McCauley, Peter; Kalachev, Leonid V; Mollicone, Daniel J; Banks, Siobhan; Dinges, David F; Van Dongen, Hans P A

    2013-12-01

    Recent experimental observations and theoretical advances have indicated that the homeostatic equilibrium for sleep/wake regulation--and thereby sensitivity to neurobehavioral impairment from sleep loss--is modulated by prior sleep/wake history. This phenomenon was predicted by a biomathematical model developed to explain changes in neurobehavioral performance across days in laboratory studies of total sleep deprivation and sustained sleep restriction. The present paper focuses on the dynamics of neurobehavioral performance within days in this biomathematical model of fatigue. Without increasing the number of model parameters, the model was updated by incorporating time-dependence in the amplitude of the circadian modulation of performance. The updated model was calibrated using a large dataset from three laboratory experiments on psychomotor vigilance test (PVT) performance, under conditions of sleep loss and circadian misalignment; and validated using another large dataset from three different laboratory experiments. The time-dependence of circadian amplitude resulted in improved goodness-of-fit in night shift schedules, nap sleep scenarios, and recovery from prior sleep loss. The updated model predicts that the homeostatic equilibrium for sleep/wake regulation--and thus sensitivity to sleep loss--depends not only on the duration but also on the circadian timing of prior sleep. This novel theoretical insight has important implications for predicting operator alertness during work schedules involving circadian misalignment such as night shift work.

  10. Performance analyses of subcarrier BPSK modulation over M turbulence channels with pointing errors

    NASA Astrophysics Data System (ADS)

    Ma, Shuang; Li, Ya-tian; Wu, Jia-bin; Geng, Tian-wen; Wu, Zhiyong

    2016-05-01

    An aggregated channel model is achieved by fitting the Weibull distribution, which includes the effects of atmospheric attenuation, M distributed atmospheric turbulence and nonzero boresight pointing errors. With this approximate channel model, the bit error rate ( BER) and the ergodic capacity of free-space optical (FSO) communication systems utilizing subcarrier binary phase-shift keying (BPSK) modulation are analyzed, respectively. A closed-form expression of BER is derived by using the generalized Gauss-Lagueree quadrature rule, and the bounds of ergodic capacity are discussed. Monte Carlo simulation is provided to confirm the validity of the BER expressions and the bounds of ergodic capacity.

  11. Development of New Low-Cost, High-Performance, PV Module Encapsulant/Packaging Materials: Final Technical Progress Report, 22 October 2002 - 15 November 2007

    SciTech Connect

    Tucker, R.

    2008-04-01

    Report on objectives to work with U.S.-based PV module manufacturers (c-Si, a-Si, CIS, other thin films) to develop/qualify new low-cost, high-performance PV module encapsulant/packaging materials, and processes using the packaging materials.

  12. Role of the null space of the DRM in the performance of modulated polarimeters.

    PubMed

    LaCasse, Charles F; Tyo, J Scott; Chipman, Russell A

    2012-03-15

    Imaging polarimeters infer the spatial distribution of the polarization state of the optical field as a function of time and/or wavelength. A polarimeter indirectly determines the polarization state by first modulating the intensity of the light field and then demodulating the measured data to infer the polarization parameters. This Letter considers passive Stokes parameter polarimeters and their inversion methods. The most widely used method is the data reduction matrix (DRM), which builds up a matrix equation that can be inverted to find the polarization state from a set of intensity measurements. An alternate strategy uses linear system formulations that allow band limited reconstruction through a filtering perspective. Here we compare these two strategies for overdetermined polarimeters and find that design of the null space of the inversion operator provides degrees of freedom to optimize the trade off between accuracy and signal-to-noise ratio. We further describe adaptive filtering techniques that could optimize the reconstruction for a particular experimental configuration. This Letter considers time-varying Stokes parameters, but the methods apply equally to polarimeters that are modulated in space or in wavelength. PMID:22446237

  13. Increasing the information rates of optical communications via coded modulation: a study of transceiver performance.

    PubMed

    Maher, Robert; Alvarado, Alex; Lavery, Domaniç; Bayvel, Polina

    2016-01-01

    Optical fibre underpins the global communications infrastructure and has experienced an astonishing evolution over the past four decades, with current commercial systems transmitting data rates in excess of 10 Tb/s over a single fibre core. The continuation of this dramatic growth in throughput has become constrained due to a power dependent nonlinear distortion arising from a phenomenon known as the Kerr effect. The mitigation of fibre nonlinearities is an area of intense research. However, even in the absence of nonlinear distortion, the practical limit on the transmission throughput of a single fibre core is dominated by the finite signal-to-noise ratio (SNR) afforded by current state-of-the-art coherent optical transceivers. Therefore, the key to maximising the number of information bits that can be reliably transmitted over a fibre channel hinges on the simultaneous optimisation of the modulation format and code rate, based on the SNR achieved at the receiver. In this work, we use an information theoretic approach based on the mutual information and the generalised mutual information to characterise a state-of-the-art dual polarisation m-ary quadrature amplitude modulation transceiver and subsequently apply this methodology to a 15-carrier super-channel to achieve the highest throughput (1.125 Tb/s) ever recorded using a single coherent receiver.

  14. Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

    PubMed

    Bok, Jan; Schauer, Petr

    2014-01-01

    In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF. PMID:24323770

  15. Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

    PubMed

    Bok, Jan; Schauer, Petr

    2014-01-01

    In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF.

  16. Increasing the information rates of optical communications via coded modulation: a study of transceiver performance

    PubMed Central

    Maher, Robert; Alvarado, Alex; Lavery, Domaniç; Bayvel, Polina

    2016-01-01

    Optical fibre underpins the global communications infrastructure and has experienced an astonishing evolution over the past four decades, with current commercial systems transmitting data rates in excess of 10 Tb/s over a single fibre core. The continuation of this dramatic growth in throughput has become constrained due to a power dependent nonlinear distortion arising from a phenomenon known as the Kerr effect. The mitigation of fibre nonlinearities is an area of intense research. However, even in the absence of nonlinear distortion, the practical limit on the transmission throughput of a single fibre core is dominated by the finite signal-to-noise ratio (SNR) afforded by current state-of-the-art coherent optical transceivers. Therefore, the key to maximising the number of information bits that can be reliably transmitted over a fibre channel hinges on the simultaneous optimisation of the modulation format and code rate, based on the SNR achieved at the receiver. In this work, we use an information theoretic approach based on the mutual information and the generalised mutual information to characterise a state-of-the-art dual polarisation m-ary quadrature amplitude modulation transceiver and subsequently apply this methodology to a 15-carrier super-channel to achieve the highest throughput (1.125 Tb/s) ever recorded using a single coherent receiver. PMID:26864633

  17. Digital test of a ΣΔ modulator in a mixed-signal BIST architecture

    NASA Astrophysics Data System (ADS)

    Rolindez, Luis; Mir, Salvador; Prenat, Guillaume

    2005-06-01

    Oversampling Sigma-Delta modulators are commonly used in the design of high-resolution Analogue-to-Digital Converters (ADCs). The test of these ΣΔ modulators is a difficult and expensive task due to the need for the generation of a high-precision analogue test signal and the necessity of complex digital resources for the test response analysis. These problems can be overcome with the integration of the test in the chip by means of Built-In Self-Test (BIST) approaches. In this paper we present a BIST technique for high-precision ΣΔ modulators, by incorporating on-chip test signal generation and on-chip test response analysis capabilities. The approach, mostly digital, is based on the application of a binary stream as test stimulus and the re-use of the digital decimation filter present in a ΣΔ ADC for the test response analysis. The binary stimulus, which encodes a sinusoidal signal, is chosen to have a very high quality in the bandwidth of interest of the modulator. For the analysis of the test response, a high-precision sinusoidal signal is necessary as reference. This reference signal can be obtained from the same binary stimulus, by passing it directly to the digital decimation filter existing in the converter. Test response and sinusoidal reference signal are both compared by means of a sine-wave curve-fitting algorithm in order to obtain a measure of the SNDR (Signal-to-Noise-plus-Distortion Ratio). Simulation results show that this technique is capable of detecting the SNDR degradations caused by non-idealities in the modulator used in a 16-bit audio ΣΔ ADC architecture.

  18. A Nomographic Methodology for Use in Performance Trade-Off Studies of Parabolic Dish Solar Power Modules

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.; Fujita, T.

    1984-01-01

    A simple graphical method was developed to undertake technical design trade-off studies for individual parabolic dish models comprising a two-axis tracking parabolic dish with a cavity receiver and power conversion assembly at the focal point. The results of these technical studies are then used in performing the techno-economic analyses required for determining appropriate subsystem sizing. Selected graphs that characterize the performance of subsystems within the module were arranged in the form of a nomogram that would enable an investigator to carry out several design trade-off studies. Key performance parameters encompassed in the nomogram include receiver losses, intercept factor, engine rating, and engine efficiency. Design and operation parameters such as concentrator size, receiver type (open or windowed aperture), receiver aperture size, operating temperature of the receiver and engine, engine partial load characteristics, concentrator slope error, and the type of reflector surface, are also included in the graphical solution. Cost considerations are not included.

  19. Multiple function fluorescein probe performs metal chelation, disaggregation, and modulation of aggregated Aβ and Aβ-Cu complex.

    PubMed

    Muthuraj, B; Layek, Sourav; Balaji, S N; Trivedi, Vishal; Iyer, Parameswar Krishnan

    2015-11-18

    An exceptional probe comprising indole-3-carboxaldehyde fluorescein hydrazone (FI) performs multiple tasks, namely, disaggregating amyloid β (Aβ) aggregates in different biomarker environments such as cerebrospinal fluid (CSF), Aβ1-40 fibrils, β-amyloid lysozyme aggregates (LA), and U87 MG human astrocyte cells. Additionally, the probe FI binds with Cu(2+) ions selectively, disrupts the Aβ aggregates that vary from few nanometers to micrometers, and prevents their reaggregation, thereby performing disaggregation and modulation of amyloid-β in the presence as well as absence of Cu(2+) ion. The excellent selectivity of probe FI for Cu(2+) was effectively utilized to modulate the assembly of metal-induced Aβ aggregates by metal chelation with the "turn-on" fluorescence via spirolactam ring opening of FI as well as the metal-free Aβ fibrils by noncovalent interactions. These results confirm that FI has exceptional ability to perform multifaceted tasks such as metal chelation in intracellular conditions using Aβ lysozyme aggregates in cellular environments by the disruption of β-sheet rich Aβ fibrils into disaggregated forms. Subsequently, it was confirmed that FI had the ability to cross the blood-brain barrier and it also modulated the metal induced Aβ fibrils in cellular environments by "turn-on" fluorescence, which are the most vital properties of a probe or a therapeutic agent. Furthermore, the morphology changes were examined by atomic force microscopy (AFM), polarizable optical microscopy (POM), fluorescence microscopy, and dynamic light scattering (DLS) studies. These results provide very valuable clues on the Aβ (CSF Aβ fibrils, Aβ1-40 fibrils, β-amyloid lysozyme aggregates) disaggregation behavior via in vitro studies, which constitute the first insights into intracellular disaggregation of Aβ by "turn-on" method thereby influencing amyloidogenesis.

  20. Investigating the performance of reconstruction methods used in structured illumination microscopy as a function of the illumination pattern's modulation frequency

    NASA Astrophysics Data System (ADS)

    Shabani, H.; Sánchez-Ortiga, E.; Preza, C.

    2016-03-01

    Surpassing the resolution of optical microscopy defined by the Abbe diffraction limit, while simultaneously achieving optical sectioning, is a challenging problem particularly for live cell imaging of thick samples. Among a few developing techniques, structured illumination microscopy (SIM) addresses this challenge by imposing higher frequency information into the observable frequency band confined by the optical transfer function (OTF) of a conventional microscope either doubling the spatial resolution or filling the missing cone based on the spatial frequency of the pattern when the patterned illumination is two-dimensional. Standard reconstruction methods for SIM decompose the low and high frequency components from the recorded low-resolution images and then combine them to reach a high-resolution image. In contrast, model-based approaches rely on iterative optimization approaches to minimize the error between estimated and forward images. In this paper, we study the performance of both groups of methods by simulating fluorescence microscopy images from different type of objects (ranging from simulated two-point sources to extended objects). These simulations are used to investigate the methods' effectiveness on restoring objects with various types of power spectrum when modulation frequency of the patterned illumination is changing from zero to the incoherent cut-off frequency of the imaging system. Our results show that increasing the amount of imposed information by using a higher modulation frequency of the illumination pattern does not always yield a better restoration performance, which was found to be depended on the underlying object. Results from model-based restoration show performance improvement, quantified by an up to 62% drop in the mean square error compared to standard reconstruction, with increasing modulation frequency. However, we found cases for which results obtained with standard reconstruction methods do not always follow the same trend.

  1. Performance of a silicon photovoltaic module under enhanced illumination and selective filtration of incoming radiation with simultaneous cooling

    SciTech Connect

    Maiti, Subarna; Vyas, Kairavi; Ghosh, Pushpito K.

    2010-08-15

    A promising option to reduce the cost of silicon photovoltaic systems is to concentrate the sunlight incident on the solar cells to increase the output power. However, this leads to higher module temperatures which affects performance adversely and may also cause long term damage. Proper cooling is therefore necessary to operate the system under concentrated radiation. The present work was undertaken to circumvent the problem in practical manner. A suitable liquid, connected to a heat exchanger, was placed in the housing of the photovoltaic module and unwanted wavelengths of solar radiation were filtered out to minimise overheating of the cells. The selection of the liquid was based on factors such as boiling point, transparency towards visible radiation, absorption of infrared and ultraviolet radiation, stability, flow characteristics, heat transfer properties, and electrical nonconductivity. Using a square parabolic type reflector, more than two fold increase in output power was realised on a clear sunny day employing a 0.13 m{sup 2} silicon solar module. Without the cooling arrangement the panel temperature rose uncontrollably. (author)

  2. Thin film CIGS photovoltaic modules: monolithic integration and advanced packaging for high performance, high reliability and low cost

    NASA Astrophysics Data System (ADS)

    Eldada, Louay

    2011-01-01

    In recent years, thin-film photovoltaic companies started realizing their low manufacturing cost potential, and have been grabbing an increasingly larger market share. Copper Indium Gallium Selenide (CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control, and a fast high-quality CIGS reaction. The reactive transfer process is a two stage CIGS fabrication method. Precursor films are deposited onto substrates and reusable cover plates in the first stage, while in the second stage the CIGS layer is formed by rapid heating with Se confinement. HelioVolt also developed best-in-class packaging technologies that provide unparalleled environmental stability. High quality CIGS films with large grains were fabricated on the production line, and high-performance highreliability monolithic modules with a form factor of 120 cm × 60 cm are being produced at high yield and low cost. With conversion efficiency levels around 14% for cells and 12% for modules, HelioVolt is commercializing the process on its first production line with 20 MW capacity, and is planning its next GW-scale factory.

  3. Both a nicotinic single nucleotide polymorphism (SNP) and a noradrenergic SNP modulate working memory performance when attention is manipulated.

    PubMed

    Greenwood, Pamela M; Sundararajan, Ramya; Lin, Ming-Kuan; Kumar, Reshma; Fryxell, Karl J; Parasuraman, Raja

    2009-11-01

    We investigated the relation between the two systems of visuospatial attention and working memory by examining the effect of normal variation in cholinergic and noradrenergic genes on working memory performance under attentional manipulation. We previously reported that working memory for location was impaired following large location precues, indicating the scale of visuospatial attention has a role in forming the mental representation of the target. In one of the first studies to compare effects of two single nucleotide polymorphisms (SNPs) on the same cognitive task, we investigated the neurotransmission systems underlying interactions between attention and memory. Based on our previous report that the CHRNA4 rs#1044396 C/T nicotinic receptor SNP affected visuospatial attention, but not working memory, and the DBH rs#1108580 G/A noradrenergic enzyme SNP affected working memory, but not attention, we predicted that both SNPs would modulate performance when the two systems interacted and working memory was manipulated by attention. We found the scale of visuospatial attention deployed around a target affected memory for location of that target. Memory performance was modulated by the two SNPs. CHRNA4 C/C homozygotes and DBH G allele carriers showed the best memory performance but also the greatest benefit of visuospatial attention on memory. Overall, however, the CHRNA4 SNP exerted a stronger effect than the DBH SNP on memory performance when visuospatial attention was manipulated. This evidence of an integrated cholinergic influence on working memory performance under attentional manipulation is consistent with the view that working memory and visuospatial attention are separate systems which can interact.

  4. Urology residents experience comparable workload profiles when performing live porcine nephrectomies and robotic surgery virtual reality training modules.

    PubMed

    Mouraviev, Vladimir; Klein, Martina; Schommer, Eric; Thiel, David D; Samavedi, Srinivas; Kumar, Anup; Leveillee, Raymond J; Thomas, Raju; Pow-Sang, Julio M; Su, Li-Ming; Mui, Engy; Smith, Roger; Patel, Vipul

    2016-03-01

    In pursuit of improving the quality of residents' education, the Southeastern Section of the American Urological Association (SES AUA) hosts an annual robotic training course for its residents. The workshop involves performing a robotic live porcine nephrectomy as well as virtual reality robotic training modules. The aim of this study was to evaluate workload levels of urology residents when performing a live porcine nephrectomy and the virtual reality robotic surgery training modules employed during this workshop. Twenty-one residents from 14 SES AUA programs participated in 2015. On the first-day residents were taught with didactic lectures by faculty. On the second day, trainees were divided into two groups. Half were asked to perform training modules of the Mimic da Vinci-Trainer (MdVT, Mimic Technologies, Inc., Seattle, WA, USA) for 4 h, while the other half performed nephrectomy procedures on a live porcine model using the da Vinci Si robot (Intuitive Surgical Inc., Sunnyvale, CA, USA). After the first 4 h the groups changed places for another 4-h session. All trainees were asked to complete the NASA-TLX 1-page questionnaire following both the MdVT simulation and live animal model sessions. A significant interface and TLX interaction was observed. The interface by TLX interaction was further analyzed to determine whether the scores of each of the six TLX scales varied across the two interfaces. The means of the TLX scores observed at the two interfaces were similar. The only significant difference was observed for frustration, which was significantly higher at the simulation than the animal model, t (20) = 4.12, p = 0.001. This could be due to trainees' familiarity with live anatomical structures over skill set simulations which remain a real challenge to novice surgeons. Another reason might be that the simulator provides performance metrics for specific performance traits as well as composite scores for entire exercises. Novice trainees experienced

  5. Urology residents experience comparable workload profiles when performing live porcine nephrectomies and robotic surgery virtual reality training modules.

    PubMed

    Mouraviev, Vladimir; Klein, Martina; Schommer, Eric; Thiel, David D; Samavedi, Srinivas; Kumar, Anup; Leveillee, Raymond J; Thomas, Raju; Pow-Sang, Julio M; Su, Li-Ming; Mui, Engy; Smith, Roger; Patel, Vipul

    2016-03-01

    In pursuit of improving the quality of residents' education, the Southeastern Section of the American Urological Association (SES AUA) hosts an annual robotic training course for its residents. The workshop involves performing a robotic live porcine nephrectomy as well as virtual reality robotic training modules. The aim of this study was to evaluate workload levels of urology residents when performing a live porcine nephrectomy and the virtual reality robotic surgery training modules employed during this workshop. Twenty-one residents from 14 SES AUA programs participated in 2015. On the first-day residents were taught with didactic lectures by faculty. On the second day, trainees were divided into two groups. Half were asked to perform training modules of the Mimic da Vinci-Trainer (MdVT, Mimic Technologies, Inc., Seattle, WA, USA) for 4 h, while the other half performed nephrectomy procedures on a live porcine model using the da Vinci Si robot (Intuitive Surgical Inc., Sunnyvale, CA, USA). After the first 4 h the groups changed places for another 4-h session. All trainees were asked to complete the NASA-TLX 1-page questionnaire following both the MdVT simulation and live animal model sessions. A significant interface and TLX interaction was observed. The interface by TLX interaction was further analyzed to determine whether the scores of each of the six TLX scales varied across the two interfaces. The means of the TLX scores observed at the two interfaces were similar. The only significant difference was observed for frustration, which was significantly higher at the simulation than the animal model, t (20) = 4.12, p = 0.001. This could be due to trainees' familiarity with live anatomical structures over skill set simulations which remain a real challenge to novice surgeons. Another reason might be that the simulator provides performance metrics for specific performance traits as well as composite scores for entire exercises. Novice trainees experienced

  6. High-performance modulation-doped AlGaAs/InGaAs thermopiles for uncooled infrared FPA application

    NASA Astrophysics Data System (ADS)

    Abe, M.; Abe, Y.; Kogushi, N.; Ang, K. S.; Hofstetter, R.; Wang, H.; Ng, G. I.

    2013-07-01

    Novel thermopile based on modulation doped AlGaAs/InGaAs heterostructures is proposed and developed for the first time, for uncooled infrared FPA (Focal Plane Array) image sensor application. The high responsivity with the high speed response time are designed to be 4900 V/W with 110 μs under the 2 μm design rule. Based on integrated HEMT-MEMS technology, the 32 × 32 matrix FPA is fabricated to demonstrate its enhanced performances by black body measurement. The technology presented here demonstrates the potential of this approach for low-cost uncooled infrared FPA image sensor application.

  7. Sintered Ag die attach as a solution to improve thermal performance of high power modules

    NASA Astrophysics Data System (ADS)

    Mansi, Mohammed S.

    The move to smaller electronics packages with higher numbers of I/Os has significantly increased power densities. The increase of power density puts more emphasis on finding solutions to improve the thermal performance of electronics packages. In wire bonded chips, the die attach layer plays a significant role in thermal performance as it establishes the main heat dissipation path from the chip. The use of sintered Ag as a die attach material to improve thermal performance is investigated in this research. A thermal simulation tool (FloTHERM) was used to study the thermal performance of five different sintered Ag die attach materials and compare their performance to the performance of silver filled epoxy die attach. Thermal simulation results showed low thermal improvement in the Theta-JA (thetaJA) value while higher thermal improvement in the Theta-JC (thetaJC) value was observed. Also, this research correlates the thermal simulation results with real-world measurements.

  8. Array Simulations Platform (ASP) predicts NASA Data Link Module (NDLM) performance

    NASA Technical Reports Server (NTRS)

    Snook, Allen David

    1993-01-01

    Through a variety of imbedded theoretical and actual antenna patterns, the array simulation platform (ASP) enhanced analysis of the array antenna pattern effects for the KTx (Ku-Band Transmit) service of the NDLM (NASA Data Link Module). The ASP utilizes internally stored models of the NDLM antennas and can develop the overall pattern of antenna arrays through common array calculation techniques. ASP expertly assisted in the diagnosing of element phase shifter errors during KTx testing and was able to accurately predict the overall array pattern from combinations of the four internally held element patterns. This paper provides an overview of the use of the ASP software in the solving of array mis-phasing problems.

  9. Performance of surface plasmon resonance imaging system based on angular modulation and intensity measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Lu-lu; Chen, Xing; Cui, Da-fu

    2016-05-01

    This paper presents a surface plasmon resonance (SPR) imaging system based on angular modulation (AM) and intensity measurement (IM) together to avoid the mechanical errors of the angle scanning device. The SPR resonant angle was found by angular scanning method and then the light intensity changes were collected at a fixed incident angle. Glycerol gradient solution (0%, 1%, 2%, 3% (weight percentage) glycerol dissolved in water) experiments were conducted, which indicate that the best fixed angle location is the middle of the linear range of SPR absorption peak and the central area signals are more uniform than those of the border areas. The sensitivity differences of different areas of SPR images are studied, and an optimized algorithm is developed.

  10. Hybrid silicon-electro-optic-polymer integrated high-performance optical modulator

    NASA Astrophysics Data System (ADS)

    Zhang, Xingyu; Hosseini, Amir; Luo, Jingdong; Jen, Alex K.-Y.; Chen, Ray T.

    2014-03-01

    We design and demonstrate a compact and low-power band-engineered electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW) modulator. The EO polymer is engineered for large EO activity and nearinfrared transparency. A PCW step coupler is used for optimum coupling to the slow-light mode of the bandengineered PCW. The half-wave switching-voltage is measured to be Vπ=0.97+/-0.02V over optical spectrum range of 8nm, corresponding to the effective in-device r33 of 1190pm/V and Vπ×L of 0.291+/-0.006V×mm in a push-pull configuration. Excluding the slow-light effect, we estimate the EO polymer is poled with an efficiency of 89pm/V in the slot.

  11. Detection performance improvement of chirped amplitude modulation ladar based on Gieger-mode avalanche photoelectric detector.

    PubMed

    Zhang, Zijing; Wu, Long; Zhang, Yu; Zhao, Yuan; Sun, Xiudong

    2011-12-10

    This paper presents an improved system structure of photon-counting chirped amplitude modulation (AM) ladar based on the Geiger-mode avalanche photoelectric detector (GmAPD). The error-pulse probability is investigated with statistical method. The research shows that most of the error pulses that are triggered by noise are distributed in the intensity troughs of the chirped AM waveform. The error-pulse probability is lowered with the sliding window and the threshold. With the average intensity of noise and signal being 0.3 count/sample and 1 count/sample, respectively, the probability of error pulses is reduced from 12% to 1.0%, and the SNR is improved by 2.2 dB in the improved system. PMID:22193131

  12. Light-induced effects-impacts to module performance measurements and reliability testing: An overview

    NASA Astrophysics Data System (ADS)

    Wronski, C. R.

    1985-10-01

    The stability of solar cells is a key factor in determining the reliability of photovoltaic modules and is of great interest in the case of solar cells having a new technology which has not yet been fully developed. In particular this question arises with hydrogenated amorphous silicon (a-Si) solar cells because a-Si exhibits reversible light induced changes in its electronic properties, commonly referred to as the Staebler-Wronski effect (SWE). Continuous progress is being made in the peak conversion efficiencies of a-Si solar cells and efficiencies in excess of 11% have been achieved. However, stability is still a problem. ARCO Solar reports results on solar cells which, after over a year's exposure to sunlight, under open circuit conditions, still have about 7% conversion efficiency. Other results show a region of fast degradation for about a month, after which the degradation diminishes rapidly.

  13. Exploring the Use of Sensorial LTP/LTD-Like Stimulation to Modulate Human Performance for Complex Visual Stimuli.

    PubMed

    Pegado, Felipe; Vankrunkelsven, Hendrik; Steyaert, Jean; Boets, Bart; Op de Beeck, Hans

    2016-01-01

    Is it possible to passively induce visual learning/unlearning in humans for complex stimuli such as faces? We addressed this question in a series of behavioral studies using passive visual stimulation (flickering of faces at specific temporal frequencies) inspired by well-known synaptic mechanisms of learning: long-term potentiation (LTP) vs long-term depression (LTD). We administered a face identity change detection task before and after a passive stimulation protocol to test for potential changes in visual performance. First, with bilateral stimulation, subjects undergoing high-frequency LTP-like stimulation outperformed those submitted to low-frequency LTD-like stimulation despite equivalent baseline performance (exp. 1). Second, unilateral stimulation replicated the differential modulation of performance, but in a hemifield-specific way (exp. 2). Third, for both stimulation groups, a sudden temporary drop in performance on the stimulated side immediately after the stimulation, followed by progressive recovering, can suggest either 'visual fatigue' or 'face adaptation' effects due to the stimulation. Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3). Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature. Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique. This step is required to consider further use in fundamental research (e.g., to study neural circuits involved in selective visual processing) and potential educational or clinical applications (e.g., inhibiting socially-irrelevant aspects of face processing in autism).

  14. Exploring the Use of Sensorial LTP/LTD-Like Stimulation to Modulate Human Performance for Complex Visual Stimuli

    PubMed Central

    Pegado, Felipe; Vankrunkelsven, Hendrik; Steyaert, Jean; Boets, Bart; Op de Beeck, Hans

    2016-01-01

    Is it possible to passively induce visual learning/unlearning in humans for complex stimuli such as faces? We addressed this question in a series of behavioral studies using passive visual stimulation (flickering of faces at specific temporal frequencies) inspired by well-known synaptic mechanisms of learning: long-term potentiation (LTP) vs long-term depression (LTD). We administered a face identity change detection task before and after a passive stimulation protocol to test for potential changes in visual performance. First, with bilateral stimulation, subjects undergoing high-frequency LTP-like stimulation outperformed those submitted to low-frequency LTD-like stimulation despite equivalent baseline performance (exp. 1). Second, unilateral stimulation replicated the differential modulation of performance, but in a hemifield-specific way (exp. 2). Third, for both stimulation groups, a sudden temporary drop in performance on the stimulated side immediately after the stimulation, followed by progressive recovering, can suggest either ‘visual fatigue’ or ‘face adaptation’ effects due to the stimulation. Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3). Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature. Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique. This step is required to consider further use in fundamental research (e.g., to study neural circuits involved in selective visual processing) and potential educational or clinical applications (e.g., inhibiting socially-irrelevant aspects of face processing in autism). PMID:27341210

  15. Exploring the Use of Sensorial LTP/LTD-Like Stimulation to Modulate Human Performance for Complex Visual Stimuli.

    PubMed

    Pegado, Felipe; Vankrunkelsven, Hendrik; Steyaert, Jean; Boets, Bart; Op de Beeck, Hans

    2016-01-01

    Is it possible to passively induce visual learning/unlearning in humans for complex stimuli such as faces? We addressed this question in a series of behavioral studies using passive visual stimulation (flickering of faces at specific temporal frequencies) inspired by well-known synaptic mechanisms of learning: long-term potentiation (LTP) vs long-term depression (LTD). We administered a face identity change detection task before and after a passive stimulation protocol to test for potential changes in visual performance. First, with bilateral stimulation, subjects undergoing high-frequency LTP-like stimulation outperformed those submitted to low-frequency LTD-like stimulation despite equivalent baseline performance (exp. 1). Second, unilateral stimulation replicated the differential modulation of performance, but in a hemifield-specific way (exp. 2). Third, for both stimulation groups, a sudden temporary drop in performance on the stimulated side immediately after the stimulation, followed by progressive recovering, can suggest either 'visual fatigue' or 'face adaptation' effects due to the stimulation. Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3). Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature. Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique. This step is required to consider further use in fundamental research (e.g., to study neural circuits involved in selective visual processing) and potential educational or clinical applications (e.g., inhibiting socially-irrelevant aspects of face processing in autism). PMID:27341210

  16. Module-scale analysis of pressure retarded osmosis: performance limitations and implications for full-scale operation.

    PubMed

    Straub, Anthony P; Lin, Shihong; Elimelech, Menachem

    2014-10-21

    We investigate the performance of pressure retarded osmosis (PRO) at the module scale, accounting for the detrimental effects of reverse salt flux, internal concentration polarization, and external concentration polarization. Our analysis offers insights on optimization of three critical operation and design parameters--applied hydraulic pressure, initial feed flow rate fraction, and membrane area--to maximize the specific energy and power density extractable in the system. For co- and counter-current flow modules, we determine that appropriate selection of the membrane area is critical to obtain a high specific energy. Furthermore, we find that the optimal operating conditions in a realistic module can be reasonably approximated using established optima for an ideal system (i.e., an applied hydraulic pressure equal to approximately half the osmotic pressure difference and an initial feed flow rate fraction that provides equal amounts of feed and draw solutions). For a system in counter-current operation with a river water (0.015 M NaCl) and seawater (0.6 M NaCl) solution pairing, the maximum specific energy obtainable using performance properties of commercially available membranes was determined to be 0.147 kWh per m(3) of total mixed solution, which is 57% of the Gibbs free energy of mixing. Operating to obtain a high specific energy, however, results in very low power densities (less than 2 W/m(2)), indicating that the trade-off between power density and specific energy is an inherent challenge to full-scale PRO systems. Finally, we quantify additional losses and energetic costs in the PRO system, which further reduce the net specific energy and indicate serious challenges in extracting net energy in PRO with river water and seawater solution pairings.

  17. Module-scale analysis of pressure retarded osmosis: performance limitations and implications for full-scale operation.

    PubMed

    Straub, Anthony P; Lin, Shihong; Elimelech, Menachem

    2014-10-21

    We investigate the performance of pressure retarded osmosis (PRO) at the module scale, accounting for the detrimental effects of reverse salt flux, internal concentration polarization, and external concentration polarization. Our analysis offers insights on optimization of three critical operation and design parameters--applied hydraulic pressure, initial feed flow rate fraction, and membrane area--to maximize the specific energy and power density extractable in the system. For co- and counter-current flow modules, we determine that appropriate selection of the membrane area is critical to obtain a high specific energy. Furthermore, we find that the optimal operating conditions in a realistic module can be reasonably approximated using established optima for an ideal system (i.e., an applied hydraulic pressure equal to approximately half the osmotic pressure difference and an initial feed flow rate fraction that provides equal amounts of feed and draw solutions). For a system in counter-current operation with a river water (0.015 M NaCl) and seawater (0.6 M NaCl) solution pairing, the maximum specific energy obtainable using performance properties of commercially available membranes was determined to be 0.147 kWh per m(3) of total mixed solution, which is 57% of the Gibbs free energy of mixing. Operating to obtain a high specific energy, however, results in very low power densities (less than 2 W/m(2)), indicating that the trade-off between power density and specific energy is an inherent challenge to full-scale PRO systems. Finally, we quantify additional losses and energetic costs in the PRO system, which further reduce the net specific energy and indicate serious challenges in extracting net energy in PRO with river water and seawater solution pairings. PMID:25222561

  18. Influence of solar spectrum and climate on the performance of c-SI, a-Si and CdTe modules

    NASA Astrophysics Data System (ADS)

    Weihs, Philipp; Jochen, Wagner; Marcus, Rennhofer; Zamini, Shokufeh; Fallent, Gerhard; Brence, Florian

    2010-05-01

    Within the scope of the project PV-SPEC we investigate the performance of different types of photovoltaic (PV) modules as a function of the regional climate of Austria. Three types of modules were chosen for the present study: monocrystalline silicon cells (c-SI), amorphous silicon cells (a-Si) and cadmium telluride cells (CdTe). The criteria for the selection of the cells is on the one hand their different spectral sensitivity and on the other hand the need of research in the domain of thin film technology. The aim of the project is the exact estimation of the potential energy yield of these three module types in the different climatic regions of Austria. Thereby the effects of the very inhomogeneous and structured topography in Austria need to be fully taken into account. As a first step the characteristics of the PV modules as well as their spectral sensitivity were determined in the laboratory. In a second step routine measurements of the module performance were performed at Observatory Kanzelhoehe (1600 m altitude), and in Vienna (170 m altitude). In order to investigate the influence of temperature, wind, cloudiness and solar spectrum some additional measurements of these quantities were performed. In order to investigate the influence of the orientation of the modules, we performed for each module type the measurement of the performance of three modules with different orientations: one module oriented towards south, one towards east and one towards west. In a third step we then analyse the performance as a function of time of the day, as a function of the season, as a function of the meteorological parameters (temperature, wind and cloudiness) and as a function of the spectral distribution of the solar radiation. The meteorological influence on the PV module performance is quantified using one array type function for each module type. Using this function and a radiative transfer model we may in a last step calculate the energy yield potential of the three PV

  19. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation: Functional modules, F9-F11

    SciTech Connect

    1997-03-01

    This Manual represents Revision 5 of the user documentation for the modular code system referred to as SCALE. The history of the SCALE code system dates back to 1969 when the current Computational Physics and Engineering Division at Oak Ridge National Laboratory (ORNL) began providing the transportation package certification staff at the U.S. Atomic Energy Commission with computational support in the use of the new KENO code for performing criticality safety assessments with the statistical Monte Carlo method. From 1969 to 1976 the certification staff relied on the ORNL staff to assist them in the correct use of codes and data for criticality, shielding, and heat transfer analyses of transportation packages. However, the certification staff learned that, with only occasional use of the codes, it was difficult to become proficient in performing the calculations often needed for an independent safety review. Thus, shortly after the move of the certification staff to the U.S. Nuclear Regulatory Commission (NRC), the NRC staff proposed the development of an easy-to-use analysis system that provided the technical capabilities of the individual modules with which they were familiar. With this proposal, the concept of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system was born. This volume consists of the section of the manual dealing with three of the functional modules in the code. Those are the Morse-SGC for the SCALE system, Heating 7.2, and KENO V.a. The manual describes the latest released versions of the codes.

  20. The M1 Muscarinic Positive Allosteric Modulator PQCA Improves Performance on Translatable Tests of Memory and Attention in Rhesus Monkeys.

    PubMed

    Lange, Henry S; Cannon, Christopher E; Drott, Jason T; Kuduk, Scott D; Uslaner, Jason M

    2015-12-01

    Improved treatment of Alzheimer disease (AD) is a significant unmet medical need that is becoming even more critical given the rise in the number of patients and the substantial economic burden. The current standards of care, acetylcholinesterase inhibitors (AChEIs), are hindered by gastrointestinal side effects owing to their nonselective activation of muscarinic and nicotinic receptors. Recently, the highly selective M1 positive allosteric modulator PQCA (1-((4-cyano-4-(pyridine-2-yl)piperidin-1-yl)methyl-4-oxo-4 H-quinolizine-3-carboxylic acid) has been demonstrated to improve cognition in a variety of rodent and nonhuman primate cognition models without producing significant gastrointestinal side effects. Here we describe the effect of PQCA and the AChEI donepezil on two clinically relevant and highly translatable touchscreen cognition tasks in nonhuman primates: paired-associates learning (PAL) and the continuous-performance task (CPT). Blockade of muscarinic signaling by scopolamine produced significant impairments in both PAL and CPT. PQCA and donepezil attenuated the scopolamine deficits in both tasks, and the action of these two compounds was similar in magnitude. In addition, the combination of subeffective doses of PQCA and donepezil enhanced PAL performance. These results further suggest that M1-positive allosteric modulators, either as monotherapy or as an add-on to current standards of care, have potential to reduce the cognitive deficits associated with AD. PMID:26446308

  1. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation: Control modules C4, C6

    SciTech Connect

    1997-03-01

    This Manual represents Revision 5 of the user documentation for the modular code system referred to as SCALE. The history of the SCALE code system dates back to 1969 when the current Computational Physics and Engineering Division at Oak Ridge National Laboratory (ORNL) began providing the transportation package certification staff at the U. S. Atomic Energy Commission with computational support in the use of the new KENO code for performing criticality safety assessments with the statistical Monte Carlo method. From 1969 to 1976 the certification staff relied on the ORNL staff to assist them in the correct use of codes and data for criticality, shielding, and heat transfer analyses of transportation packages. However, the certification staff learned that, with only occasional use of the codes, it was difficult to become proficient in performing the calculations often needed for an independent safety review. Thus, shortly after the move of the certification staff to the U.S. Nuclear Regulatory Commission (NRC), the NRC staff proposed the development of an easy-to-use analysis system that provided the technical capabilities of the individual modules with which they were familiar. With this proposal, the concept of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system was born. This volume is part of the manual related to the control modules for the newest updated version of this computational package.

  2. Comparative study on the performance of power and bandwidth efficient modulations in LMSS under fading and interference

    NASA Technical Reports Server (NTRS)

    Liu, Jian; Kim, Junghwan; Kwatra, S. C.; Stevens, Grady H.

    1991-01-01

    Aspects of error performance of various power and bandwidth efficient modulations for the land mobile satellite systems (LMSS) were investigated under multipath fading and interferences by using Monte-Carlo simulation. A differential detection for 16QAM (quadrature amplitude modulation) was proposed to cope with Ricean fading and Doppler shift. Computer simulation results show that the performance of 16QAM with differential detection is as good as that of 16PSK with coherent detection and 3 dB better than that of 16PSK with differential detection, although it degrades by about 4.5 dB as compared to 16QAM with coherent detection under an additive white Gaussian noise (AWGN) channel. For the nonlinear channels, 16QAM with modified signal constellations is introduced and analyzed. The simulation results show that the modified 16QAM exhibits a gain of 2.5 dB over 16PSK under traveling-wave tube nonlinearity, and about 4 dB gain over 16PSK at the bit error rate of 10 exp -5 under AWGN. Computer simulation results for modified 16 QAM under cochannel interference and adjacent-channel interference are also presented.

  3. Low cost and high performance GPON, GEPON and RFoG optical network pentaplexer module design using diffractive grating approach

    NASA Astrophysics Data System (ADS)

    Chen, I.-Ju; Chi, Chang-Chia; Tarn, Chen-Wen

    2016-01-01

    A new architecture of a pentaplexer transceiver module which can be used in GPON/GEPON and RFoG triple play optical networks with supporting of the multiple optical wavelengths of 1310 nm, 1490 nm, 1550 nm, 1610 nm, and 1650 nm, is proposed. By using diffractive grating elements combing with market readily available GRIN (Gradient-Index) lens, grating, mirrors, beamsplitter, LDs (Laser Diodes), and PDs (Photodetectors), the proposed design have the advantages of low cost, high efficiency/performance, easy design and manufacturing, over the contemporary triplex transceivers which are made of multilayer filters or waveguides that increase the complexity of manufacturing and reduce the performance efficiency. With the proposed design, a pentaplexer system can accommodate GPON/GEPON, RFoG, and monitoring integration services, total five optical wavelength channels into a hybrid-integrated TO-CAN package platform with sufficient efficiency.

  4. The impact of pulsed RFI on the coded BER performance of the nonlinear satellite communication channel. [with BPSK modulation

    NASA Technical Reports Server (NTRS)

    Weinberg, A.

    1981-01-01

    An examination is conducted of the coded bit error rate (BER) performance of a satellite communication system in which binary phase-shift-keyed (BPSK) modulation is employed, pulsed CW or pulsed noise RFI is present, and the transponder contains a nonlinearity characterized by arbitrary AM/AM and AM/PM characteristics; the RFI pulse duration is further assumed to exceed that of the information symbol. Computed performance curves consider several hypothetical RFI scenarios in which either a hard limiter or an 8 dB clipper represent the transponder amplitude nonlinearity. Results demonstrate the potential seriousness of RFI duty cycles as low as 2 percent, and the fact that CW represents the most severe form of interference.

  5. Time of day does not modulate improvements in motor performance following a repetitive ballistic motor training task.

    PubMed

    Sale, Martin V; Ridding, Michael C; Nordstrom, Michael A

    2013-01-01

    Repetitive performance of a task can result in learning. The neural mechanisms underpinning such use-dependent plasticity are influenced by several neuromodulators. Variations in neuromodulator levels may contribute to the variability in performance outcomes following training. Circulating levels of the neuromodulator cortisol change throughout the day. High cortisol levels inhibit neuroplasticity induced with a transcranial magnetic stimulation (TMS) paradigm that has similarities to use-dependent plasticity. The present study investigated whether performance changes following a motor training task are modulated by time of day and/or changes in endogenous cortisol levels. Motor training involving 30 minutes of repeated maximum left thumb abduction was undertaken by twenty-two participants twice, once in the morning (8 AM) and once in the evening (8 PM) on separate occasions. Saliva was assayed for cortisol concentration. Motor performance, quantified by measuring maximum left thumb abduction acceleration, significantly increased by 28% following training. Neuroplastic changes in corticomotor excitability of abductor pollicis brevis, quantified with TMS, increased significantly by 23% following training. Training-related motor performance improvements and neuroplasticity were unaffected by time of day and salivary cortisol concentration. Although similar neural elements and processes contribute to motor learning, training-induced neuroplasticity, and TMS-induced neuroplasticity, our findings suggest that the influence of time of day and cortisol differs for these three interventions.

  6. Performance of a 300 Mbps 1:16 serial/parallel optoelectronic receiver module

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Claspy, P. C.; Bhasin, K. B.; Bendett, M. B.

    1990-01-01

    Optical interconnects are being considered for the high speed distribution of multiplexed control signals in GaAs monolithic microwave integrated circuit (MMIC) based phased array antennas. The performance of a hybrid GaAs optoelectronic integrated circuit (OEIC) is described, as well as its design and fabrication. The OEIC converts a 16-bit serial optical input to a 16 parallel line electrical output using an on-board 1:16 demultiplexer and operates at data rates as high as 30b Mbps. The performance characteristics and potential applications of the device are presented.

  7. Performance of a 300 Mbps 1:16 serial/parallel optoelectronic receiver module

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Claspy, P. C.; Bhasin, K. B.; Bendett, M. P.

    1990-01-01

    Optical interconnects are being considered for the high speed distribution of multiplexed control signals in GaAs MMIC-based phased array antennas. This paper describes the performance of a hybrid GaAs optoelectronic integrated circuit (OEIC), along with a description of its design and fabrication. The OEIC converts a 16-bit serial optical input to a 16 parallel line electrical output using an on-board 1:16 demultiplexer and operates at data rates as high as 305 Mbps. The performance characteristics as well as potential applications of the device are presented.

  8. A comprehensive simulation model of the performance of photochromic films in absorbance-modulation-optical-lithography

    NASA Astrophysics Data System (ADS)

    Majumder, Apratim; Helms, Phillip L.; Andrew, Trisha L.; Menon, Rajesh

    2016-03-01

    Optical lithography is the most prevalent method of fabricating micro-and nano-scale structures in the semiconductor industry due to the fact that patterning using photons is fast, accurate and provides high throughput. However, the resolution of this technique is inherently limited by the physical phenomenon of diffraction. Absorbance-Modulation-Optical Lithography (AMOL), a recently developed technique has been successfully demonstrated to be able to circumvent this diffraction limit. AMOL employs a dual-wavelength exposure system in conjunction with spectrally selective reversible photo-transitions in thin films of photochromic molecules to achieve patterning of features with sizes beyond the far-field diffraction limit. We have developed a finite-element-method based full-electromagnetic-wave solution model that simulates the photo-chemical processes that occur within the thin film of the photochromic molecules under illumination by the exposure and confining wavelengths in AMOL. This model allows us to understand how the material characteristics influence the confinement to sub-diffraction dimensions, of the transmitted point spread function (PSF) of the exposure wavelength inside the recording medium. The model reported here provides the most comprehensive analysis of the AMOL process to-date, and the results show that the most important factors that govern the process, are the polarization of the two beams, the ratio of the intensities of the two wavelengths, the relative absorption coefficients and the concentration of the photochromic species, the thickness of the photochromic layer and the quantum yields of the photoreactions at the two wavelengths. The aim of this work is to elucidate the requirements of AMOL in successfully circumventing the far-field diffraction limit.

  9. Effects of off-resonance spins on the performance of the modulated gradient spin echo sequence

    NASA Astrophysics Data System (ADS)

    Serša, Igor; Bajd, Franci; Mohorič, Aleš

    2016-09-01

    Translational molecular dynamics in various materials can also be studied by diffusion spectra. These can be measured by a constant gradient variant of the modulated gradient spin echo (MGSE) sequence which is composed of a CPMG RF pulse train superimposed to a constant magnetic field gradient. The application of the RF train makes the effective gradient oscillating thus enabling measurements of diffusion spectra in a wide range of frequencies. However, seemingly straightforward implementation of the MGSE sequence proved to be complicated and can give overestimated results for diffusion if not interpreted correctly. In this study, unrestricted diffusion in water and other characteristic materials was analyzed by the MGSE sequence in the frequency range 50-3000 Hz using a 6 T/m diffusion probe. First, it was shown that the MGSE echo train acquired from the entire sample decays faster than the train acquired only from a narrow band at zero frequency of the sample. Then, it was shown that the decay rate is dependent on the band's off-resonance characterized by the ratio Δω0 /ω1 and that with higher off-resonances the decay is faster. The faster decay therefore corresponds to a higher diffusion coefficient if the diffusion is calculated using standard Stejskal-Tanner formula. The result can be explained by complex coherence pathways contributing to the MGSE echo signals when | Δω0 | /ω1 > 0 . In a magnetic field gradient, all the pathways are more diffusion attenuated than the direct coherence pathway and therefore decay faster, which leads to an overestimation of the diffusion coefficient. A solution to this problem was found in an efficient off-resonance signal reduction by using only zero frequency filtered MGSE echo train signals.

  10. Electrical and Optical Performance Characteristics of p/n InGaAs Monolithic Interconnected Modules

    NASA Technical Reports Server (NTRS)

    Wilt, David M.; Fatemi, Navid S.; Jenkins, Phillip P.; Weizer, Victor G.; Hoffman, Richard W., Jr.; Murray, Christopher S.; Riley, David R.

    1997-01-01

    There has been a traditional trade-off in ThermoPhotoVoltaic (TPV) energy conversion development between system efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A Monolithic Interconnected Module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual Indium Gallium Arsenide (InGaAs) devices series-connected on a single semi-insulating Indium Phosphide (InP) substrate. The MIMs are exposed to the entire emitter output, thereby maximizing output power density. An InfraRed (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 sq cm device consisting of eight (8) series interconnected cells. MIM devices, produced from 0.74eV InGaAs, have demonstrated V(sub infinity) = 3.2 volts, J(sub sc) = 70 mA/sq cm and a fill factor of 66% under flashlamp testing. IR reflectance measurements (greater than 2 microns) of these devices indicate a reflectivity of greater than 82%. MIM devices produced from 0.55 eV InGaAs have also been demonstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM0) have been demonstrated.

  11. Load Modulation of BOLD Response and Connectivity Predicts Working Memory Performance in Younger and Older Adults

    ERIC Educational Resources Information Center

    Nagel, Irene E.; Preuschhof, Claudia; Li, Shu-Chen; Nyberg, Lars; Backman, Lars; Lindenberger, Ulman; Heekeren, Hauke R.

    2011-01-01

    Individual differences in working memory (WM) performance have rarely been related to individual differences in the functional responsivity of the WM brain network. By neglecting person-to-person variation, comparisons of network activity between younger and older adults using functional imaging techniques often confound differences in activity…

  12. Wavefront-Error Performance Characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Science Instruments

    NASA Technical Reports Server (NTRS)

    Aronstein, David L.; Smith, J. Scott; Zielinski, Thomas P.; Telfer, Randal; Tournois, Severine C.; Moore, Dustin B.; Fienup, James R.

    2016-01-01

    The science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES) test chamber. In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing, and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) F-number and pupil-distortion measurements made using a pseudo-nonredundant mask (PNRM), and 3) pupil geometry predictions as a function of SI and field point, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse translation diversity sweeps instead of focus sweeps, in which a sub-aperture is translated and/or rotated across the exit pupil of the system. Several optical-performance requirements that were verified during this ISIM-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also describes the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis of focus-sweep data, used to establish

  13. Wavefront-Error Performance Characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Science Instruments

    NASA Technical Reports Server (NTRS)

    Aronstein, David L.; Smith, J. Scott; Zielinski, Thomas P.; Telfer, Randal; Tournois, Severine C.; Moore, Dustin B.; Fienup, James R.

    2016-01-01

    The science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES). In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing (also known as phase retrieval), and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) plate scale measurements made using a Pseudo-Nonredundant Mask (PNRM), and 3) pupil geometry predictions as a function of SI and field point, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse translation diversity sweeps instead of focus sweeps, in which a sub-aperture is translated andor rotated across the exit pupil of the system.Several optical-performance requirements that were verified during this ISIM-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also describes the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis of focus-sweep data, used to establish the

  14. Visuo-motor coordination ability predicts performance with brain-computer interfaces controlled by modulation of sensorimotor rhythms (SMR).

    PubMed

    Hammer, Eva M; Kaufmann, Tobias; Kleih, Sonja C; Blankertz, Benjamin; Kübler, Andrea

    2014-01-01

    Modulation of sensorimotor rhythms (SMR) was suggested as a control signal for brain-computer interfaces (BCI). Yet, there is a population of users estimated between 10 to 50% not able to achieve reliable control and only about 20% of users achieve high (80-100%) performance. Predicting performance prior to BCI use would facilitate selection of the most feasible system for an individual, thus constitute a practical benefit for the user, and increase our knowledge about the correlates of BCI control. In a recent study, we predicted SMR-BCI performance from psychological variables that were assessed prior to the BCI sessions and BCI control was supported with machine-learning techniques. We described two significant psychological predictors, namely the visuo-motor coordination ability and the ability to concentrate on the task. The purpose of the current study was to replicate these results thereby validating these predictors within a neurofeedback based SMR-BCI that involved no machine learning.Thirty-three healthy BCI novices participated in a calibration session and three further neurofeedback training sessions. Two variables were related with mean SMR-BCI performance: (1) a measure for the accuracy of fine motor skills, i.e., a trade for a person's visuo-motor control ability; and (2) subject's "attentional impulsivity". In a linear regression they accounted for almost 20% in variance of SMR-BCI performance, but predictor (1) failed significance. Nevertheless, on the basis of our prior regression model for sensorimotor control ability we could predict current SMR-BCI performance with an average prediction error of M = 12.07%. In more than 50% of the participants, the prediction error was smaller than 10%. Hence, psychological variables played a moderate role in predicting SMR-BCI performance in a neurofeedback approach that involved no machine learning. Future studies are needed to further consolidate (or reject) the present predictors.

  15. Visuo-motor coordination ability predicts performance with brain-computer interfaces controlled by modulation of sensorimotor rhythms (SMR)

    PubMed Central

    Hammer, Eva M.; Kaufmann, Tobias; Kleih, Sonja C.; Blankertz, Benjamin; Kübler, Andrea

    2014-01-01

    Modulation of sensorimotor rhythms (SMR) was suggested as a control signal for brain-computer interfaces (BCI). Yet, there is a population of users estimated between 10 to 50% not able to achieve reliable control and only about 20% of users achieve high (80–100%) performance. Predicting performance prior to BCI use would facilitate selection of the most feasible system for an individual, thus constitute a practical benefit for the user, and increase our knowledge about the correlates of BCI control. In a recent study, we predicted SMR-BCI performance from psychological variables that were assessed prior to the BCI sessions and BCI control was supported with machine-learning techniques. We described two significant psychological predictors, namely the visuo-motor coordination ability and the ability to concentrate on the task. The purpose of the current study was to replicate these results thereby validating these predictors within a neurofeedback based SMR-BCI that involved no machine learning.Thirty-three healthy BCI novices participated in a calibration session and three further neurofeedback training sessions. Two variables were related with mean SMR-BCI performance: (1) a measure for the accuracy of fine motor skills, i.e., a trade for a person’s visuo-motor control ability; and (2) subject’s “attentional impulsivity”. In a linear regression they accounted for almost 20% in variance of SMR-BCI performance, but predictor (1) failed significance. Nevertheless, on the basis of our prior regression model for sensorimotor control ability we could predict current SMR-BCI performance with an average prediction error of M = 12.07%. In more than 50% of the participants, the prediction error was smaller than 10%. Hence, psychological variables played a moderate role in predicting SMR-BCI performance in a neurofeedback approach that involved no machine learning. Future studies are needed to further consolidate (or reject) the present predictors. PMID:25147518

  16. Phytase Modulates Ileal Microbiota and Enhances Growth Performance of the Broiler Chickens

    PubMed Central

    Ptak, Anna; Bedford, Michael R.; Świątkiewicz, Sylwester; Żyła, Krzysztof; Józefiak, Damian

    2015-01-01

    Phytase is well studied and explored, however, little is known about its effects on the microbial ecology of the gastrointestinal tract. In total, 400 one-day-old female Ross 308 chicks were randomly distributed to four experimental groups. The dietary treatments were arranged as a 2 × 2 complete factorial design, with the factors being adequate (PC) or insufficient calcium (Ca) and digestible phosphor (dP)(NC) and with or without 5000 phytase units (FTU)/kg of Escherichia coli 6-phytase. The gastrointestinal tract pH values, ileal microbial communities and short-chain fatty acid concentrations in the digesta were determined. The reduction in Ca and dP concentration significantly affected pH in the crop and caeca, and addition of phytase to the NC resulted in a pH increase in the ileum. The reduction in Ca and dP concentration significantly lowered, while phytase supplementation increased ileal total bacterial counts. Additionally, the deficient diet reduced butyrate- but increased lactate-producing bacteria. The addition of phytase increased Lactobacillus sp./Enterococcus sp. whereas in case of Clostridium leptum subgroup, Clostridium coccoides - Eubacterium rectale cluster, Bifidobacterium sp. and Streptococcus/Lactococcus counts, a significant Ca and dP level x phytase interaction was found. However, the recorded interactions indicated that the effects of phytase and Ca and dP levels were not consistent. Furthermore, the reduction of Ca and dP level lowered Clostridium perfringens and Enterobacteriaceae counts. The analysis of fermentation products showed that reducing the Ca and dP content in the diet reduced total SCFA, DL-lactate, and acetic acid in the ileum whereas phytase increased concentrations of these acids in the NC group. This suggests that P is a factor which limits fermentation in the ileum. It may be concluded that phytase plays a role in modulating the gut microbiota of chicken, however, this is clearly linked with the levels of P and Ca in a

  17. Low-Temperature Ozone Exposure Technique to Modulate the Stoichiometry of WO(x) Nanorods and Optimize the Electrochromic Performance

    SciTech Connect

    Lin, F.; Li, C. P.; Chen, G.; Tenent, R. C.; Wolden, C. A.; Gillaspie, D. T.; Dillon, A. C.; Richards, R. M.; Engtrakul, C.

    2012-06-29

    A low-temperature ozone exposure technique was employed for the post-treatment of WO{sub x} nanorod thin films fabricated from hot-wire chemical vapor deposition (HWCVD) and ultrasonic spray deposition (USD) techniques. The resulting films were characterized with x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, UV-vis-NIR spectroscopy and x-ray photoelectron spectroscopy (XPS). The stoichiometry and surface crystallinity of the WO{sub x} thin films were subsequently modulated upon ozone exposure and thermal annealing without particle growth. The electrochromic performance was studied in a LiClO{sub 4}-propylene carbonate electrolyte, and the results suggest that the low-temperature ozone exposure technique is superior to the traditional high-temperature thermal annealing (employed to more fully oxidize the WO{sub x}). The optical modulation at 670 nm was improved from 35% for the as-deposited film to 57% for the film after ozone exposure at 150 C. The coloration efficiency was improved and the switching speed to the darkened state was significantly accelerated from 18.0 s for the as-deposited film to 11.8 s for the film after the ozone exposure. The process opens an avenue for low-temperature and cost-effective manufacturing of electrochromic films, especially on flexible polymer substrates.

  18. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    SciTech Connect

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  19. Apollo 11 Mission Report, Supplement 5: Performance of Lunar Module Reaction Control Systems

    NASA Technical Reports Server (NTRS)

    Blevins, D. R.; Jenkins, L. W.

    1971-01-01

    Spacecraft velocity data and crew reports indicated that RCS engine performance was nominal. It is estimated that the RCS engines accumulated a total of 1060 seconds on-time and 12,000 firings during the mission. The quad temperatures ranged from 132 to 232 F during the period when the heaters were active, within predicated ranges. The total propellant consumption from the RCS tanks was about 319 pounds, compared to a predicted value of 253 pounds. An additional 69 pounds of propellant were used from the ascent propulsion system tanks during interconnect feed operations associated with APS lift-off, following periods of rapid propellant usage. The only problems noted were two thrust chamber pressure switch failures on the quad one down-firing engine and on the quad 2 aft-firing engine. Engine performance was nominal on both engines, and the switch failures had no effect on the mission.

  20. DRD2/ANKK1 polymorphism modulates the effect of ventral striatal activation on working memory performance.

    PubMed

    Nymberg, Charlotte; Banaschewski, Tobias; Bokde, Arun L W; Büchel, Christian; Conrod, Patricia; Flor, Herta; Frouin, Vincent; Garavan, Hugh; Gowland, P; Heinz, Andreas; Ittermann, Bernd; Mann, Karl; Martinot, Jean-Luc; Nees, Frauke; Paus, Tomas; Pausova, Zdenka; Rietschel, Marcella; Robbins, Trevor W; Smolka, Michael N; Ströhle, Andreas; Schumann, Gunter; Klingberg, Torkel

    2014-09-01

    Motivation is important for learning and cognition. Although dopaminergic (D2) transmission in the ventral striatum (VS) is associated with motivation, learning, and cognition are more strongly associated with function of the dorsal striatum, including activation in the caudate nucleus. A recent study found an interaction between intrinsic motivation and the DRD2/ANKK1 polymorphism (rs1800497), suggesting that A-carriers of rs1800497 are significantly more sensitive to motivation in order to improve during working memory (WM) training. Using data from the two large-scale imaging genetic data sets, IMAGEN (n=1080, age 13-15 years) and BrainChild (n∼300, age 6-27), we investigated whether rs1800497 is associated with WM. In the IMAGEN data set, we tested whether VS/caudate activation during reward anticipation was associated with WM performance and whether rs1800497 and VS/caudate activation interact to affect WM performance. We found that rs1800497 was associated with WM performance in IMAGEN and BrainChild. Higher VS and caudate activation during reward processing were significantly associated with higher WM performance (p<0.0001). An interaction was found between the DRD2/ANKK1 polymorphism rs1800497 and VS activation during reward anticipation on WM (p<0.01), such that carriers of the minor allele (A) showed a significant correlation between VS activation and WM, whereas the GG-homozygotes did not, suggesting that the effect of VS BOLD on WM is modified by inter-individual genetic differences related to D2 dopaminergic transmission. PMID:24713612

  1. Performance Testing of a Photocatalytic Oxidation Module for Spacecraft Cabin Atmosphere Revitalization

    NASA Technical Reports Server (NTRS)

    Perry, Jay L.; Abney, Morgan B.; Frederick, Kenneth R.; Scott, Joseph P.; Kaiser, Mark; Seminara, Gary; Bershitsky, Alex

    2011-01-01

    Photocatalytic oxidation (PCO) is a candidate process technology for use in high volumetric flow rate trace contaminant control applications in sealed environments. The targeted application for PCO as applied to crewed spacecraft life support system architectures is summarized. Technical challenges characteristic of PCO are considered. Performance testing of a breadboard PCO reactor design for mineralizing polar organic compounds in a spacecraft cabin atmosphere is described. Test results are analyzed and compared to results reported in the literature for comparable PCO reactor designs.

  2. Hydrothermal synthesis of vanadium nitride and modulation of its catalytic performance for oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Huang, Taizhong; Mao, Shun; Zhou, Guihua; Wen, Zhenhai; Huang, Xingkang; Ci, Suqin; Chen, Junhong

    2014-07-01

    A creative hydrothermal synthesis method followed by calcination for vanadium nitride (VN) is reported. The oxygen reduction reaction (ORR) study of the catalyst shows that VN possesses a comparable catalytic performance to commercial Pt/C catalyst. The ORR catalytic activity study of vanadium nitride, vanadium carbonitride, and vanadium carbide reveals that tuning anions offers a promising route for the activity enhancement of the non-precious metal catalysts.A creative hydrothermal synthesis method followed by calcination for vanadium nitride (VN) is reported. The oxygen reduction reaction (ORR) study of the catalyst shows that VN possesses a comparable catalytic performance to commercial Pt/C catalyst. The ORR catalytic activity study of vanadium nitride, vanadium carbonitride, and vanadium carbide reveals that tuning anions offers a promising route for the activity enhancement of the non-precious metal catalysts. Electronic supplementary information (ESI) available: Experimental methods; SEM characterization of the catalysts; Tafel test of Pt/C catalyst; BET and cyclic performance tests of VN. See DOI: 10.1039/c4nr02646b

  3. Sleep Transistor Sizing According to Circuit Speed, Silicon Area and Leakage Current in High-Performance Digital Circuit Modules

    NASA Astrophysics Data System (ADS)

    Kucukkomurler, Ahmet; Garverick, Steven L.

    It is proposed that the power supply of key circuit modules could be gated to achieve significant reductions of leakage current, with minimal costs to circuit speed and die area in 0.25, 0.18 and 0.07 µm technologies. This study describes an extension to power supply gating using body overdrive and gate underdrive, analysis techniques to predict leakage current and performance parameters, a procedure for optimization of the sleep transistor size and simulation results that demonstrate the accuracy of the analysis and advantages of the approach. A leakage current estimation technique has been studied using the Berkeley Predictive Technology Model Parameters. An estimation technique has been verified using ISCAS85 combinational Benchmark test circuits. Finally the optimization algorithm has been verified using these same benchmark test circuits.

  4. ZnMgO by APCVD Enabling High-Performance Mid-bandgap CIGS on Polyimide Modules: October 2009--October 2010

    SciTech Connect

    Woods, L.

    2011-04-01

    This Pre-Incubator project was designed to increase the 'real world' CIGS based photovoltaic module performance and decrease the Levelized Cost of Energy (LCOE) of systems utilizing those modules compared to our traditional CIGS based photovoltaic modules. This was enabled by a) increasing the CIGS bandgap and b) developing better matched device finishing layers to the mid-bandgap CIGS based photovoltaics; including window and buffer layers (and eventually the TCO). Incremental progress in the novel device performance was demonstrated throughout the program, and ultimately achieved performance results that exceeded the milestones ahead of schedule. Metal-oxide buffer layer devices with mid-bandgap CIGS alloys on polyimide substrates were produced with efficiencies of over 12%. Corresponding mid-bandgap devices with CdS buffers produced over 13% efficient devices. Furthermore, no obvious degradation in the device performance has been observed to date, after proper storage ambient of the different types of unencapsulated devices were identified.

  5. An adaptive multiple-input multiple-output analog-to-digital converter for high density neuroprosthetic electrode arrays.

    PubMed

    Chakrabartty, Shantanu; Gore, Amit; Oweiss, Karim G

    2006-01-01

    On chip signal compression is one of the key technologies driving development of energy efficient biotelemetry devices. In this paper, we describe a novel architecture for analog-to-digital (A/D) conversion that combines sigma delta conversion with the spatial data compression in a single module. The architecture called multiple-input multiple-output (MIMO) sigma-delta is based on a min-max gradient descent optimization of a regularized cost function that naturally leads to an A/D formulation. Experimental results with simulated and recorded multichannel data demonstrate the effectiveness of the proposed architecture to eliminate cross-channel redundancy in high density microelectrode data, thus superceding the performance of parallel independent data converters in terms of its energy efficiency.

  6. Performance of ferroelectric liquid crystal spatial light modulators for polarization and color diffractive elements

    NASA Astrophysics Data System (ADS)

    Moreno, Ignacio; García-Martínez, P.; Sánchez-López, M. M.; Martínez-García, A.; Martínez, J. L.

    2009-08-01

    In this work we applied a ferroelectric liquid crystal on silicon (FLCoS) display for implementing monochrome and color diffractive optical elements (DOE). We first apply a reverse engineering process specifically adapted to characterize the optical parameters of a commercial FLCoS display, specifically the phase shift and the tilt angle. We then analyze the performance of the device for implementing a binary polarization diffraction grating (PDG), and how it adopts the form of either a binary amplitude grating or a binary phase grating as particular cases when the polarization states emerging from the display are projected to an analyzer. As a final experiment, we have applied the FLCoS display to generate RGB improved dynamic color binary-phase Fourier computer-generated holograms (CGHs). We have electronically synchronized the properly scaled image addressed to the display with a color filter wheel with RGB filters. Experimental results show an excellent chromatic compensation of the color image reconstruction.

  7. Relative language proficiency modulates BOLD signal change when bilinguals perform semantic judgments. Blood oxygen level dependent.

    PubMed

    Chee, M W; Hon, N; Lee, H L; Soon, C S

    2001-06-01

    The effect of relative language proficiency on the spatial distribution and magnitude of BOLD signal change was evaluated by studying two groups of right-handed English-Mandarin bilingual participants with contrasting language proficiencies as they made semantic judgments with words and characters. Greater language proficiency corresponded to shorter response times and greater accuracy in the semantic judgment task. Within the left prefrontal and parietal regions, the change in BOLD signal was smaller in a participant's more proficient language. The least proficient performance was associated with right, in addition to left, inferior frontal activation. The results highlight the importance of taking into consideration nature of task and relative language proficiency when drawing inferences from functional imaging studies of bilinguals.

  8. Dietary Nisin Modulates the Gastrointestinal Microbial Ecology and Enhances Growth Performance of the Broiler Chickens

    PubMed Central

    Józefiak, Damian; Kierończyk, Bartosz; Juśkiewicz, Jerzy; Zduńczyk, Zenon; Rawski, Mateusz; Długosz, Jakub; Sip, Anna; Højberg, Ole

    2013-01-01

    Due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. Surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (GIT). The present study therefore aimed at investigating effects of dietary nisin on broiler chicken GIT microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. In total, 720 one-day-old male Ross 308 chicks were randomly distributed to six experimental groups. The positive control (PC) diet was supplemented with salinomycin (60 mg/kg). The nisin (NI) diets were supplemented with increasing levels (100, 300, 900 and 2700 IU nisin/g, respectively) of the bacteriocin. The negative control (NC) diet contained no additives. At slaughter (35 days of age), activity of specific bacterial enzymes (α- and β-glucosidases, α-galactosidases and β-glucuronidase) in crop, ileum and caeca were significantly higher (P<0.05) in the NC group, and nisin supplementation decreased the enzyme activities to levels observed for the PC group. A similar inhibitory influence on bacterial activity was reflected in the levels of short-chain fatty acids (SCFA) and putrefactive SCFA (PSCFA) in digesta from crop and ileum; no effect was observed in caeca. Counts of Bacteroides and Enterobacteriacae in ileum digesta were significantly (P<0.001) decreased by nisin and salinomycin, but no effects were observed on the counts of Clostridium perfringens, Lactobacillus/Enterococcus and total bacteria. Like salinomycin, nisin supplementation improved broiler growth performance in a dose-dependent manner; compared to the NC group, the body weight gain of the NI900 and NI2700 groups was improved by 4.7 and 8.7%, respectively. Our findings suggest that dietary nisin exerts a mode of action similar to salinomycin and could be considered as a dietary supplement for broiler

  9. Dietary nisin modulates the gastrointestinal microbial ecology and enhances growth performance of the broiler chickens.

    PubMed

    Józefiak, Damian; Kierończyk, Bartosz; Juśkiewicz, Jerzy; Zduńczyk, Zenon; Rawski, Mateusz; Długosz, Jakub; Sip, Anna; Højberg, Ole

    2013-01-01

    Due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. Surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (GIT). The present study therefore aimed at investigating effects of dietary nisin on broiler chicken GIT microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. In total, 720 one-day-old male Ross 308 chicks were randomly distributed to six experimental groups. The positive control (PC) diet was supplemented with salinomycin (60 mg/kg). The nisin (NI) diets were supplemented with increasing levels (100, 300, 900 and 2700 IU nisin/g, respectively) of the bacteriocin. The negative control (NC) diet contained no additives. At slaughter (35 days of age), activity of specific bacterial enzymes (α- and β-glucosidases, α-galactosidases and β-glucuronidase) in crop, ileum and caeca were significantly higher (P<0.05) in the NC group, and nisin supplementation decreased the enzyme activities to levels observed for the PC group. A similar inhibitory influence on bacterial activity was reflected in the levels of short-chain fatty acids (SCFA) and putrefactive SCFA (PSCFA) in digesta from crop and ileum; no effect was observed in caeca. Counts of Bacteroides and Enterobacteriacae in ileum digesta were significantly (P<0.001) decreased by nisin and salinomycin, but no effects were observed on the counts of Clostridium perfringens, Lactobacillus/Enterococcus and total bacteria. Like salinomycin, nisin supplementation improved broiler growth performance in a dose-dependent manner; compared to the NC group, the body weight gain of the NI₉₀₀ and NI₂₇₀₀ groups was improved by 4.7 and 8.7%, respectively. Our findings suggest that dietary nisin exerts a mode of action similar to salinomycin and could be considered as a dietary supplement

  10. Function of basal ganglia in bridging cognitive and motor modules to perform an action

    PubMed Central

    Nagano-Saito, Atsuko; Martinu, Kristina; Monchi, Oury

    2014-01-01

    The basal ganglia (BG) are thought to be involved in the integration of multiple sources of information, and their dysfunction can lead to disorders such as Parkinson's disease (PD). PD patients show motor and cognitive dysfunction with specific impairments in the internal generation of motor actions and executive deficits, respectively. The role of the BG, then, would be to integrate information from several sources in order to make a decision on a resulting action adequate for the required task. Reanalyzing the data set from our previous study (Martinu et al., 2012), we investigated this hypothesis by applying a graph theory method to a series of fMRI data during the performance of self-initiated (SI) finger movement tasks obtained in healthy volunteers (HV) and early stage PD patients. Dorsally, connectivity strength between the medial prefrontal areas (mPFC) and cortical regions including the primary motor area (M1), the extrastriate visual cortex, and the associative cortex, was reduced in the PD patients. The connectivity strengths were positively correlated to activity in the striatum in both groups. Ventrally, all connectivity between the striatum, the thalamus, and the extrastriate visual cortex decreased in strength in the PD, as did the connectivity between the striatum and the ventrolateral PFC (VLPFC). Individual response time (RT) was negatively correlated to connectivity strength between the dorsolateral PFC (DLPFC) and the striatum and positively correlated to connectivity between the VLPFC and the striatum in the HV. These results indicate that the BG, with the mPFC and thalamus, are involved in integrating multiple sources of information from areas such as DLPFC, and VLPFC, connecting to M1, thereby determining a network that leads to the adequate decision and performance of the resulting action. PMID:25071432

  11. Does Testosterone Modulate Mood States and Physical Performance in Young Basketball Players?

    PubMed

    Miloski, Bernardo; Aoki, Marcelo S; de Freitas, Camila G; Schultz de Arruda, Ademir F; de Moraes, Helena S; Drago, Gustavo; Borges, Thiago O; Moreira, Alexandre

    2015-09-01

    This study aimed to examine and compare mood states profile and physical performance during different training phases between 2 groups of adolescent basketball players that were differentiated according to baseline testosterone concentration (T). The basketball players were submitted to an intensified training period (OVL) followed by a tapering period (TP). Twenty-three young male basketball players initiated the study. Experimental criteria data were used to stratify 16 players into high-testosterone (HTC) or low-testosterone (LTC) concentration groups. All the 16 athletes undertook 5 weeks of OVL followed by a 3-week TP. Saliva sampling, Yo-Yo intermittent recovery level 1 (Yo-Yo IRL1) test and the T-test were conducted at the beginning (T1), after OVL (T2), and after TP (T3). A similar increase in internal training load was observed during OVL when compared with TP in both groups (p < 0.05). No difference in mood states was observed between groups (p > 0.05); however, LTC displayed a higher score for fatigue (p < 0.05) and a lower score for energy index (p < 0.05) in OVL, compared with TP. A significant improvement in the Yo-Yo IRL1 test and the T-test was observed (T1 to T3) (p < 0.05), with no difference between groups (p > 0.05). In conclusion, these results suggest that LTC athletes may be more susceptible to changes in mood states during intensified training periods. In addition, data indicate that a periodized training program successfully improved the physical performance (endurance and agility) of young basketball players; however, this improvement was not affected by testosterone level.

  12. A little elastic for a better performance: kinesiotaping of the motor effector modulates neural mechanisms for rhythmic movements

    PubMed Central

    Bravi, Riccardo; Quarta, Eros; Cohen, Erez J.; Gottard, Anna; Minciacchi, Diego

    2014-01-01

    A rhythmic motor performance is brought about by an integration of timing information with movements. Investigations on the millisecond time scale distinguish two forms of time control, event-based timing and emergent timing. While event-based timing asserts the existence of a central internal timekeeper for the control of repetitive movements, the emergent timing perspective claims that timing emerges from dynamic control of nontemporal movements parameters. We have recently demonstrated that the precision of an isochronous performance, defined as performance of repeated movements having a uniform duration, was insensible to auditory stimuli of various characteristics (Bravi et al., 2014). Such finding has led us to investigate whether the application of an elastic therapeutic tape (Kinesio® Tex taping; KTT) used for treating athletic injuries and a variety of physical disorders, is able to reduce the timing variability of repetitive rhythmic movement. Young healthy subjects, tested with and without KTT, have participated in sessions in which sets of repeated isochronous wrist's flexion-extensions (IWFEs) were performed under various auditory conditions and during their recall. Kinematics was recorded and temporal parameters were extracted and analyzed. Our results show that the application of KTT decreases the variability of rhythmic movements by a 2-fold effect: on the one hand KTT provides extra proprioceptive information activating cutaneous mechanoreceptors, on the other KTT biases toward the emergent timing thus modulating the processes for rhythmic movements. Therefore, KTT appears able to render movements less audio dependent by relieving, at least partially, the central structures from time control and making available more resources for an augmented performance. PMID:25309355

  13. Enhancing the performance of multi-crystalline silicon photovoltaic module by encapsulating high efficient Eu3+ complex into its pre-existing EVA layer

    NASA Astrophysics Data System (ADS)

    Wang, Tongxin; Yu, Bo; Hu, Zhijia; Wang, Xin; Zou, Gang; Zhang, Qijin

    2013-03-01

    Luminescent down shifting (LDS) technique is one effective way to improve the poor response of multi-crystalline silicon (mc-Si) photovoltaic (PV) modules at short wavelength less than 400 nm. Eu3+ complexes are effective LDS species for PV modules due to their large stokes' shift and high luminescent quantum efficiency (LQE). Although Eu3+ complexes have been utilized in PV modules as LDS species widely, they have not been encapsulated into the pre-existing poly-ethylene vinyl acetate (EVA) layer of modules between glass and solar cell by now. The aim of our work is to enhance the performance of mc-Si PV modules by encapsulating high efficient Eu3+ complexes into their pre-existing EVA layers which would not modify the well-established manufacturing process for PV modules. In this work, two Eu3+ complexes with different absorption spectrum were encapsulated into the commercial EVA layer by soaking method for the first time and used in the encapsulation of mc-Si PV modules. Hereinto, Eu(TTA)3(TPPO)2 (TTA = 2-thenoyltrifluoroacetonate, TPPO = triphenylphosphine oxide) (EuTT) with absorption spectrum less than 400 nm and high LQE (0.73) improves the external quantum efficiency of mc-Si PV module from 0.05 to 0.20, which produces a 0.42% increases in its power conversion efficiency. In addition, it is found that the enhancement brought by Eu(TTA)3(TPPO)2 can reduce cost of power generated by mc-Si devices from US1/Wp to US0.98/Wp according to the calculation. Therefore, Eu(TTA)3(TPPO)2 as LDS species with high LQE and low cost is promising for enhancing the performance of mc-Si PV modules in practical application.

  14. Modulation of cognitive performance and mood by aromas of peppermint and ylang-ylang.

    PubMed

    Moss, Mark; Hewitt, Steven; Moss, Lucy; Wesnes, Keith

    2008-01-01

    This study provides further evidence for the impact of the aromas of plant essential oils on aspects of cognition and mood in healthy participants. One hundred and forty-four volunteers were randomly assigned to conditions of ylang-ylang aroma, peppermint aroma, or no aroma control. Cognitive performance was assessed using the Cognitive Drug Research computerized assessment battery, with mood scales completed before and after cognitive testing. The analysis of the data revealed significant differences between conditions on a number of the factors underpinning the tests that constitute the battery. Peppermint was found to enhance memory whereas ylang-ylang impaired it, and lengthened processing speed. In terms of subjective mood peppermint increased alertness and ylang-ylang decreased it, but significantly increased calmness. These results provide support for the contention that the aromas of essential oils can produce significant and idiosyncratic effects on both subjective and objective assessments of aspects of human behavior. They are discussed with reference to possible pharmacological and psychological modes of influence. PMID:18041606

  15. Systematic investigation of organic photovoltaic cell charge injection/performance modulation by dipolar organosilane interfacial layers.

    PubMed

    Song, Charles Kiseok; White, Alicia C; Zeng, Li; Leever, Benjamin J; Clark, Michael D; Emery, Jonathan D; Lou, Sylvia J; Timalsina, Amod; Chen, Lin X; Bedzyk, Michael J; Marks, Tobin J

    2013-09-25

    With the goal of investigating and enhancing anode performance in bulk-heterojunction (BHJ) organic photovoltaic (OPV) cells, the glass/tin-doped indium oxide (ITO) anodes are modified with a series of robust silane-tethered bis(fluoroaryl)amines to form self-assembled interfacial layers (IFLs). The modified ITO anodes are characterized by contact angle measurements, X-ray reflectivity, ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, grazing incidence X-ray diffraction, atomic force microscopy, and cyclic voltammetry. These techniques reveal the presence of hydrophobic amorphous monolayers of 6.68 to 9.76 Å thickness, and modified anode work functions ranging from 4.66 to 5.27 eV. Two series of glass/ITO/IFL/active layer/LiF/Al BHJ OPVs are fabricated with the active layer = poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester (P3HT:PC71BM) or poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)-carbonyl]thi-eno[3,4-b]thiophenediyl

  16. Modulating Cationic Ratios for High-Performance Transparent Solution-Processed Electronics.

    PubMed

    John, Rohit Abraham; Nguyen, Anh Chien; Chen, Yuxin; Shukla, Sudhanshu; Chen, Shi; Mathews, Nripan

    2016-01-20

    Amorphous oxide semiconductors such as indium zinc tin oxide (IZTO) are considered favorites to serve as channel materials for thin film transistors (TFTs) because they combine high charge carrier mobility with high optical transmittance, allowing for the development of transparent electronics. Although the influence of relative cationic concentrations in determining the electronic properties have been studied in sputtered and PLD films, the development of printed transparent electronics hinges on such dependencies being explored for solution-processed systems. Here, we study solution-processed indium zinc tin oxide thin film transistors (TFTs) to investigate variation in their electrical properties with change in cationic composition. Charge transport mobility ranging from 0.3 to 20.3 cm(2)/(V s), subthreshold swing ranging from 1.2 to 8.4 V/dec, threshold voltage ranging from -50 to 5 V, and drain current on-off ratio ranging from 3 to 6 orders of magnitude were obtained by examining different compositions of the semiconductor films. Mobility was found to increase with the incorporation of large cations such as In(3+) and Sn(4+) due to the vast s-orbital overlap they can achieve when compared to the intercationic distance. Subthreshold swing decreased with an increase in Zn(2+) concentration due to reduced interfacial state formation between the semiconductor and dielectric. The optimized transistor obtained at a compositional ratio of In/Zn/Sn = 1:1:1, exhibited a high field-effect mobility of 8.62 cm(2)/(V s), subthreshold swing of 1.75 V/dec, and current on-off ratio of 10(6). Such impressive performances reaffirm the promise of amorphous metal oxide semiconductors for printed electronics.

  17. Modulating Cationic Ratios for High-Performance Transparent Solution-Processed Electronics.

    PubMed

    John, Rohit Abraham; Nguyen, Anh Chien; Chen, Yuxin; Shukla, Sudhanshu; Chen, Shi; Mathews, Nripan

    2016-01-20

    Amorphous oxide semiconductors such as indium zinc tin oxide (IZTO) are considered favorites to serve as channel materials for thin film transistors (TFTs) because they combine high charge carrier mobility with high optical transmittance, allowing for the development of transparent electronics. Although the influence of relative cationic concentrations in determining the electronic properties have been studied in sputtered and PLD films, the development of printed transparent electronics hinges on such dependencies being explored for solution-processed systems. Here, we study solution-processed indium zinc tin oxide thin film transistors (TFTs) to investigate variation in their electrical properties with change in cationic composition. Charge transport mobility ranging from 0.3 to 20.3 cm(2)/(V s), subthreshold swing ranging from 1.2 to 8.4 V/dec, threshold voltage ranging from -50 to 5 V, and drain current on-off ratio ranging from 3 to 6 orders of magnitude were obtained by examining different compositions of the semiconductor films. Mobility was found to increase with the incorporation of large cations such as In(3+) and Sn(4+) due to the vast s-orbital overlap they can achieve when compared to the intercationic distance. Subthreshold swing decreased with an increase in Zn(2+) concentration due to reduced interfacial state formation between the semiconductor and dielectric. The optimized transistor obtained at a compositional ratio of In/Zn/Sn = 1:1:1, exhibited a high field-effect mobility of 8.62 cm(2)/(V s), subthreshold swing of 1.75 V/dec, and current on-off ratio of 10(6). Such impressive performances reaffirm the promise of amorphous metal oxide semiconductors for printed electronics. PMID:26695104

  18. Modulation of mood and cognitive performance following acute administration of Melissa officinalis (lemon balm).

    PubMed

    Kennedy, D O; Scholey, Andrew B; Tildesley, N T J; Perry, E K; Wesnes, K A

    2002-07-01

    Melissa officinalis (lemon balm) is a traditional herbal medicine, which enjoys contemporary usage as a mild sedative, spasmolytic and antibacterial agent. It has been suggested, in light of in vitro cholinergic binding properties, that Melissa extracts may effectively ameliorate the cognitive deficits associated with Alzheimer's disease. To date, no study has investigated the effects on cognition and mood of administration of Melissa to healthy humans. The present randomised, placebo-controlled, double-blind, balanced-crossover study investigated the acute effects on cognition and mood of a standardised extract of M. officinalis. Twenty healthy, young participants received single doses of 300, 600 and 900 mg of M. officinalis (Pharmaton) or a matching placebo at 7-day intervals. Cognitive performance was assessed using the Cognitive Drug Research (CDR) computerised test battery and two serial subtraction tasks immediately prior to dosing and at 1, 2.5, 4 and 6 h thereafter. In vitro IC(50) concentrations for the displacement of [3H]-(N)-nicotine and [3H]-(N)-scopolamine from nicotinic and muscarinic receptors in human occipital cortex tissue were also calculated. Results, utilising the cognitive factors previously derived from the CDR battery, included a sustained improvement in Accuracy of Attention following 600 mg of Melissa and time- and dose-specific reductions in both Secondary Memory and Working Memory factors. Self-rated "calmness," as assessed by Bond-Lader mood scales, was elevated at the earliest time points by the lowest dose, whilst "alertness" was significantly reduced at all time points following the highest dose. Both nicotinic and muscarinic binding were found to be low in comparison to the levels found in previous studies.

  19. Water Stress Modulates Soybean Aphid Performance, Feeding Behavior, and Virus Transmission in Soybean

    PubMed Central

    Nachappa, Punya; Culkin, Christopher T.; Saya, Peter M.; Han, Jinlong; Nalam, Vamsi J.

    2016-01-01

    Little is known about how water stress including drought and flooding modifies the ability of plants to resist simultaneous attack by insect feeding and transmission of insect-vectored pathogen. We analyzed insect population growth, feeding behaviors, virus transmission, and plant amino acid profiles and defense gene expression to characterize mechanisms underlying the interaction between water stress, soybean aphid and aphid-transmitted, Soybean mosaic virus, on soybean plants. Population growth of non-viruliferous aphids was reduced under drought stress and saturation, likely because the aphids spent less time feeding from the sieve element on these plants compared to well-watered plants. Water stress did not impact population growth of viruliferous aphids. However, virus incidence and transmission rate was lowest under drought stress and highest under saturated conditions since viruliferous aphids took the greatest amount time to puncture cells and transmit the virus under saturated conditions and lowest time under drought stress. Petiole exudates from drought-stressed plants had the highest level of total free amino acids including asparagine and valine that are critical for aphid performance. Aphids did not benefit from improved phloem sap quality as indicated by their lower densities on drought-stressed plants. Saturation, on the other hand, resulted in low amino acid content compared to all of the other treatments. Drought and saturation had significant and opposing effects on expression of marker genes involved in abscisic acid (ABA) signaling. Drought alone significantly increased expression of ABA marker genes, which likely led to suppression of salicylic acid (SA)- and jasmonic acid (JA)-related genes. In contrast, ABA marker genes were down-regulated under saturation, while expression of SA- and JA-related genes was up-regulated. We propose that the apparent antagonism between ABA and SA/JA signaling pathways contributed to an increase in aphid

  20. Water Stress Modulates Soybean Aphid Performance, Feeding Behavior, and Virus Transmission in Soybean.

    PubMed

    Nachappa, Punya; Culkin, Christopher T; Saya, Peter M; Han, Jinlong; Nalam, Vamsi J

    2016-01-01

    Little is known about how water stress including drought and flooding modifies the ability of plants to resist simultaneous attack by insect feeding and transmission of insect-vectored pathogen. We analyzed insect population growth, feeding behaviors, virus transmission, and plant amino acid profiles and defense gene expression to characterize mechanisms underlying the interaction between water stress, soybean aphid and aphid-transmitted, Soybean mosaic virus, on soybean plants. Population growth of non-viruliferous aphids was reduced under drought stress and saturation, likely because the aphids spent less time feeding from the sieve element on these plants compared to well-watered plants. Water stress did not impact population growth of viruliferous aphids. However, virus incidence and transmission rate was lowest under drought stress and highest under saturated conditions since viruliferous aphids took the greatest amount time to puncture cells and transmit the virus under saturated conditions and lowest time under drought stress. Petiole exudates from drought-stressed plants had the highest level of total free amino acids including asparagine and valine that are critical for aphid performance. Aphids did not benefit from improved phloem sap quality as indicated by their lower densities on drought-stressed plants. Saturation, on the other hand, resulted in low amino acid content compared to all of the other treatments. Drought and saturation had significant and opposing effects on expression of marker genes involved in abscisic acid (ABA) signaling. Drought alone significantly increased expression of ABA marker genes, which likely led to suppression of salicylic acid (SA)- and jasmonic acid (JA)-related genes. In contrast, ABA marker genes were down-regulated under saturation, while expression of SA- and JA-related genes was up-regulated. We propose that the apparent antagonism between ABA and SA/JA signaling pathways contributed to an increase in aphid

  1. CUMAS: a seafloor multi-sensor module for volcanic hazard monitoring - First long-term experiment and performance assessment

    NASA Astrophysics Data System (ADS)

    Iannaccone, G.; Guardato, S.; Vassallo, M.; Stabile, T. A.; Elia, L.; Beranzoli, L.

    2009-12-01

    A seafloor multi-sensor module with real-time data transmission, named CUMAS (Cabled Underwater Module for Acquisition of Seismological data), has been deployed in January 2008 in the Gulf of Pozzuoli, in the Campi Flegrei caldera (southern Italy), which is one of the most active volcanic areas in the world. The sensors installed in CUMAS were selected to monitor a set of signals related to the local seismicity as well as the ground uplift and subsidence of the seafloor that are related to the bradyseismic phenomenon. In particular, together with a broad-band three-component seismometer and a low-frequency hydrophone, a seafloor water-pressure sensor is used to assess the feasibility of measurements of the slow vertical movement of the seafloor (bradyseism). Further sensors are acquired by two embedded Linux computers, namely tilt and heading sensors for the measure of the actual module orientation on the seafloor, and status sensors that monitor the state of health of the vessel (e.g., internal temperature, power absorption, water intrusion). The underwater acquisition systems are linked to a support infrastructure, a floating buoy (elastic beacon), through an electro-mechanical cable with an Ethernet line. The buoy provides the needed power supply thanks to batteries charged by solar panels and a wind- generator. A Wi-Fi antenna on the buoy is used to transmit the seafloor data from the sea surface to the land acquisition centre in the city of Naples. A meteorological station is also mounted on the buoy, to allow the correlation of the air and seafloor data. CUMAS, although based on commercial sensors, relies on an original system for the centralized management of a wide set of geophysical and physical oceanographic sensors, that handles the continuous data acquisition and real-time data transmission. After the installation in the Gulf of Pozzuoli at about 100 m w.d., and after a test period, CUMAS uninterruptedly operated from May 2008 to June 2009, thus

  2. Dynamic modulation of shared sensory and motor cortical rhythms mediates speech and non-speech discrimination performance

    PubMed Central

    Bowers, Andrew L.; Saltuklaroglu, Tim; Harkrider, Ashley; Wilson, Matt; Toner, Mary A.

    2014-01-01

    Oscillatory models of speech processing have proposed that rhythmic cortical oscillations in sensory and motor regions modulate speech sound processing from the bottom-up via phase reset at low frequencies (3–10 Hz) and from the top-down via the disinhibition of alpha/beta rhythms (8–30 Hz). To investigate how the proposed rhythms mediate perceptual performance, electroencephalographic (EEG) was recorded while participants passively listened to or actively identified speech and tone-sweeps in a two-force choice in noise discrimination task presented at high and low signal-to-noise ratios. EEG data were decomposed using independent component analysis and clustered across participants using principle component methods in EEGLAB. Left and right hemisphere sensorimotor and posterior temporal lobe clusters were identified. Alpha and beta suppression was associated with active tasks only in sensorimotor and temporal clusters. In posterior temporal clusters, increases in phase reset at low frequencies were driven by the quality of bottom-up acoustic information for speech and non-speech stimuli, whereas phase reset in sensorimotor clusters was associated with top-down active task demands. A comparison of correct discrimination trials to those identified at chance showed an earlier performance related effect for the left sensorimotor cluster relative to the left-temporal lobe cluster during the syllable discrimination task only. The right sensorimotor cluster was associated with performance related differences for tone–sweep stimuli only. Findings are consistent with internal model accounts suggesting that early efferent sensorimotor models transmitted along alpha and beta channels reflect a release from inhibition related to active attention to auditory discrimination. Results are discussed in the broader context of dynamic, oscillatory models of cognition proposing that top-down internally generated states interact with bottom-up sensory processing to enhance task

  3. Wavefront-error performance characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) science instruments

    NASA Astrophysics Data System (ADS)

    Aronstein, David L.; Smith, J. S.; Zielinski, Thomas P.; Telfer, Randal; Tournois, Severine C.; Moore, Dustin B.; Fienup, James R.

    2016-07-01

    The science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES) test chamber. In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing, and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) f/# and pupil-distortion measurements made using a pseudo-nonredundant mask (PNRM), and 3) pupil-geometry predictions for each SI field point tested, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse-translation diversity (TTD) sweeps instead of focus sweeps, in which a subaperture is translated and/or rotated across the exit pupil of the system from one image to the next. Several optical-performance requirements that were verified during this ISIM Element-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also gives an overview of the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis

  4. Human dopamine receptor nanovesicles for gate-potential modulators in high-performance field-effect transistor biosensors

    PubMed Central

    Park, Seon Joo; Song, Hyun Seok; Kwon, Oh Seok; Chung, Ji Hyun; Lee, Seung Hwan; An, Ji Hyun; Ahn, Sae Ryun; Lee, Ji Eun; Yoon, Hyeonseok; Park, Tai Hyun; Jang, Jyongsik

    2014-01-01

    The development of molecular detection that allows rapid responses with high sensitivity and selectivity remains challenging. Herein, we demonstrate the strategy of novel bio-nanotechnology to successfully fabricate high-performance dopamine (DA) biosensor using DA Receptor-containing uniform-particle-shaped Nanovesicles-immobilized Carboxylated poly(3,4-ethylenedioxythiophene) (CPEDOT) NTs (DRNCNs). DA molecules are commonly associated with serious diseases, such as Parkinson's and Alzheimer's diseases. For the first time, nanovesicles containing a human DA receptor D1 (hDRD1) were successfully constructed from HEK-293 cells, stably expressing hDRD1. The nanovesicles containing hDRD1 as gate-potential modulator on the conducting polymer (CP) nanomaterial transistors provided high-performance responses to DA molecule owing to their uniform, monodispersive morphologies and outstanding discrimination ability. Specifically, the DRNCNs were integrated into a liquid-ion gated field-effect transistor (FET) system via immobilization and attachment processes, leading to high sensitivity and excellent selectivity toward DA in liquid state. Unprecedentedly, the minimum detectable level (MDL) from the field-induced DA responses was as low as 10 pM in real- time, which is 10 times more sensitive than that of previously reported CP based-DA biosensors. Moreover, the FET-type DRNCN biosensor had a rapid response time (<1 s) and showed excellent selectivity in human serum. PMID:24614248

  5. Superior thermoelectric performance in PbTe-PbS pseudo-binary. Extremely low thermal conductivity and modulated carrier concentration

    DOE PAGES

    Wu, D.; Zhao, L. -D.; Tong, X.; Li, W.; Wu, L.; Tan, Q.; Pei, Y.; Huang, L.; Li, J. -F.; Zhu, Y.; et al

    2015-05-19

    Lead chalcogenides have exhibited their irreplaceable role as thermoelectric materials at the medium temperature range, owing to highly degenerate electronic bands and intrinsically low thermal conductivities. PbTe-PbS pseudo-binary has been paid extensive attentions due to the even lower thermal conductivity which originates largely from the coexistence of both alloying and phase-separated precipitations. To investigate the competition between alloying and phase separation and its pronounced effect on the thermoelectric performance in PbTe-PbS, we systematically studied Spark Plasma Sintered (SPSed), 3 at% Na- doped (PbTe)1-x(PbS)x samples with x=10%, 15%, 20%, 25%, 30% and 35% by means of transmission electron microscopy (TEM) observationsmore » and theoretical calculations. Corresponding to the lowest lattice thermal conductivity as a result of the balance between point defect- and precipitates- scattering, the highest figure of merit ZT~2.3 was obtained at 923 K when PbS phase fraction x is at 20%. The consistently lower lattice thermal conductivities in SPSed samples compared with corresponding ingots, resulting from the powdering and follow-up consolidation processes, also contribute to the observed superior ZT. Notably, the onset of carrier concentration modulation ~600 K due to excessive Na’s diffusion and re-dissolution leads to the observed saturations of electrical transport properties, which is believed equally crucial to the outstanding thermoelectric performance of SPSed PbTe-PbS samples.« less

  6. Human dopamine receptor nanovesicles for gate-potential modulators in high-performance field-effect transistor biosensors

    NASA Astrophysics Data System (ADS)

    Park, Seon Joo; Song, Hyun Seok; Kwon, Oh Seok; Chung, Ji Hyun; Lee, Seung Hwan; An, Ji Hyun; Ahn, Sae Ryun; Lee, Ji Eun; Yoon, Hyeonseok; Park, Tai Hyun; Jang, Jyongsik

    2014-03-01

    The development of molecular detection that allows rapid responses with high sensitivity and selectivity remains challenging. Herein, we demonstrate the strategy of novel bio-nanotechnology to successfully fabricate high-performance dopamine (DA) biosensor using DA Receptor-containing uniform-particle-shaped Nanovesicles-immobilized Carboxylated poly(3,4-ethylenedioxythiophene) (CPEDOT) NTs (DRNCNs). DA molecules are commonly associated with serious diseases, such as Parkinson's and Alzheimer's diseases. For the first time, nanovesicles containing a human DA receptor D1 (hDRD1) were successfully constructed from HEK-293 cells, stably expressing hDRD1. The nanovesicles containing hDRD1 as gate-potential modulator on the conducting polymer (CP) nanomaterial transistors provided high-performance responses to DA molecule owing to their uniform, monodispersive morphologies and outstanding discrimination ability. Specifically, the DRNCNs were integrated into a liquid-ion gated field-effect transistor (FET) system via immobilization and attachment processes, leading to high sensitivity and excellent selectivity toward DA in liquid state. Unprecedentedly, the minimum detectable level (MDL) from the field-induced DA responses was as low as 10 pM in real- time, which is 10 times more sensitive than that of previously reported CP based-DA biosensors. Moreover, the FET-type DRNCN biosensor had a rapid response time (<1 s) and showed excellent selectivity in human serum.

  7. Superior thermoelectric performance in PbTe-PbS pseudo-binary. Extremely low thermal conductivity and modulated carrier concentration

    SciTech Connect

    Wu, D.; Zhao, L. -D.; Tong, X.; Li, W.; Wu, L.; Tan, Q.; Pei, Y.; Huang, L.; Li, J. -F.; Zhu, Y.; Kanatzidis, M. G.; He, J.

    2015-05-19

    Lead chalcogenides have exhibited their irreplaceable role as thermoelectric materials at the medium temperature range, owing to highly degenerate electronic bands and intrinsically low thermal conductivities. PbTe-PbS pseudo-binary has been paid extensive attentions due to the even lower thermal conductivity which originates largely from the coexistence of both alloying and phase-separated precipitations. To investigate the competition between alloying and phase separation and its pronounced effect on the thermoelectric performance in PbTe-PbS, we systematically studied Spark Plasma Sintered (SPSed), 3 at% Na- doped (PbTe)1-x(PbS)x samples with x=10%, 15%, 20%, 25%, 30% and 35% by means of transmission electron microscopy (TEM) observations and theoretical calculations. Corresponding to the lowest lattice thermal conductivity as a result of the balance between point defect- and precipitates- scattering, the highest figure of merit ZT~2.3 was obtained at 923 K when PbS phase fraction x is at 20%. The consistently lower lattice thermal conductivities in SPSed samples compared with corresponding ingots, resulting from the powdering and follow-up consolidation processes, also contribute to the observed superior ZT. Notably, the onset of carrier concentration modulation ~600 K due to excessive Na’s diffusion and re-dissolution leads to the observed saturations of electrical transport properties, which is believed equally crucial to the outstanding thermoelectric performance of SPSed PbTe-PbS samples.

  8. In-Situ Measurement of Crystalline Silicon Modules Undergoing Potential-Induced Degradation in Damp Heat Stress Testing for Estimation of Low-Light Power Performance

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Kurtz, S.

    2013-08-01

    The extent of potential-induced degradation of crystalline silicon modules in an environmental chamber is estimated using in-situ dark I-V measurements and applying superposition analysis. The dark I-V curves are shown to correctly give the module power performance at 200, 600 and 1,000 W/m2 irradiance conditions, as verified with a solar simulator. The onset of degradation measured in low light in relation to that under one sun irradiance can be clearly seen in the module design examined; the time to 5% relative degradation measured in low light (200 W/m2) was 28% less than that of full sun (1,000 W/m2 irradiance). The power of modules undergoing potential-induced degradation can therefore be characterized in the chamber, facilitating statistical analyses and lifetime forecasting.

  9. Final Report for Award DE-SC0005403. Improved Electrochemical Performance of Strained Lattice Electrolytes via Modulated Doping

    SciTech Connect

    Hertz, Joshua L.; Prasad, Ajay K.

    2015-09-06

    The enclosed document provides a final report to document the research performed at the University of Delaware under Grant DE-SC0005403: Improved Electrochemical Performance of Strained Lattice Electrolytes via Modulated Doping. The ultimate goal of this project was to learn how to systematically strain the inter-atomic distance in thin ceramic films and how to use this newfound control to improve the ease by which oxygen ions can conduct through the films. Increasing the ionic conductivity of ceramics holds the promise of drastic improvements in the performance of solid oxide fuel cells, chemical sensors, gas permeation membranes, and related devices. Before this work, the experimental evidence advocating for strain-based techniques was often controversial and poorly characterized. Enabling much of this work was a new method to quickly create a very wide range of ceramic nanostructures that was established during the first phase of the project. Following this initial phase, we created a variety of promising nanostructured epitaxial films and multilayers with systematic variations in lattice mismatch and dopant content. Over the course of the work, a positive effect of tensile atomic strain on the oxygen conductivity was conclusively found using a few different forms of samples and experimental techniques. The samples were built by sputtering, an industrially scalable technique, and thus the technological implementation of these results may be economically feasible. Still, two other results consistently achieved over multiple efforts in this work give pause. The first of these results was that very specific, pristine surfaces upon which to build the nanostructures were strictly required in order to achieve measurable results. The second of these results was that compressively strained films with concomitant reductions in oxygen conductivity are much easier to obtain relative to tensile-strained films with increased conductivity.

  10. Long distance high performance remote strain sensing with a fiber Fabry-Perot by radio-frequency laser modulation

    NASA Astrophysics Data System (ADS)

    Chow, Jong H.; Littler, Ian C. M.; McClelland, David E.; Gray, Malcolm B.

    2006-05-01

    We use a radio-frequency (RF) diode laser modulation technique to interrogate a fiber Fabry-Perot (FFP), and demonstrate unprecedented remote sensitivity performance for measuring fiber dynamic strain. We present results for its experimental demonstration in a 5 km remote strain sensing system, where we have attained sub-picostrain/√Hz resolution in an acoustic signal band from 100 Hz to 100 kHz, with better than 300 femtostrain/√Hz sensitivity above 300 Hz. This is unprecedented in sensitivity and broadband performance, unparalleled over such a long interrogation distance. Strain signals are extracted interferometrically from the differential phase between the carrier and its RF sidebands. This elegant architecture is immune to intensity noise in the laser, as well as ambient acoustic and mechanical perturbations in the remote delivery fiber. The excellent frequency discrimination by the FFP also facilitates a superior signal-to-noise ratio, to effectively overcome the random phase noise due to Rayleigh backscatter in the long length of fiber. Furthermore, the interrogation length can be well beyond the coherence length of the laser source. We show that this performance is limited only by the frequency noise of the diode laser source, as all systemic noise sources in the delivery fiber are effectively transparent to the sensing architecture. This remote sensitivity is a seminal demonstration for a range of applications, such as sea floor acoustic sensing arrays, deep sea hydrophone arrays, and remote surveillance. We will discuss upscaling of this single element experiment to multi-element sensing arrays.

  11. Menstrual cycle phase modulates reward sensitivity and performance monitoring in young women: Preliminary fMRI evidence.

    PubMed

    Diekhof, Esther K; Ratnayake, Melanie

    2016-04-01

    The ability to learn from errors or the positive outcomes of one's actions has been connected to a differential functionality of the mesolimbic dopamine system. Variations in dopaminergic transmission and D2-receptor (DRD2) density in the striatum may thereby incline the individual to be either more reward- or punishment-sensitive. The steroid hormones estradiol (E2) and progesterone (PROG) are known to modulate dopaminergic tone. While E2 may enhance dopaminergic release and reduces DRD2, PROG may oppose these effects and attenuates dopaminergic responses. In women, marked changes in the concentration of these hormones occur across the menstrual cycle. Hence, the aim of this study was to assess whether reinforcement learning is modulated by menstrual cycle phase. Fifteen female subjects underwent fMRI while performing a probabilistic feedback learning task twice during their menstrual cycle--once in a phase dominated by E2 (late follicular phase), and a second time in the presence of high PROG (mid luteal phase).The goal of the learning task was to select the more frequently rewarded symbols from 3 symbol pairs, which was enforced by probabilistic feedback. A behavioral post-test examined learning performance and the tendency towards reward or punishment sensitivity (i.e., preference to choose the most often rewarded symbol 'A' or to avoid the least often rewarded symbol 'B', respectively). We found that individual reward sensitivity was enhanced in the follicular relative to the luteal phase, while the ability to learn from negative feedback was compromised. In contrast, during the luteal phase this behavior was reversed and women showed an enhanced punishment learning bias. On the neural level, activation of the dorsal anterior cingulate cortex and adjacent rostral cingulate zone (dACC/RCZ) was decreased when subjects received negative feedback in the follicular relative to the luteal phase. Additionally, in the luteal phase an enhanced ability to learn from

  12. Performance of electric forklift with low-temperature polymer exchange membrane fuel cell power module and metal hydride hydrogen storage extension tank

    NASA Astrophysics Data System (ADS)

    Lototskyy, Mykhaylo V.; Tolj, Ivan; Parsons, Adrian; Smith, Fahmida; Sita, Cordellia; Linkov, Vladimir

    2016-06-01

    We present test results of a commercial 3-tonne electric forklift (STILL) equipped with a commercial fuel cell power module (Plug Power) and a MH hydrogen storage tank (HySA Systems and TF Design). The tests included: (i) performance evaluation of "hybrid" hydrogen storage system during refuelling at low (<185 bar) dispensing pressures; (ii) comparison of the forklift performances during heavy-duty operation when changing the powering in the series: standard battery - fuel cell power module (alone) - power module with integrated MH tank; and (iii) performance tests of the forklift during its operation under working conditions. It was found that (a) the forklift with power module and MH tank can achieve 83% of maximum hydrogen storage capacity during 6 min refuelling (for full capacity 12-15 min); (b) heavy-duty operation of the forklift is characterised by 25% increase in energy consumption, and during system operation more uniform power distribution occurs when operating in the fuel cell powering mode with MH, in comparison to the battery powering mode; (c) use of the fully refuelled fuel cell power module with the MH extension tank allows for uninterrupted operation for 3 h 6 min and 7 h 15 min, for heavy- and light-duty operation, respectively.

  13. THE PERFORMANCE OF THE 8.4 MW MODULATOR/REGULATOR POWE SYSTEMS FOR THE ELECTRON CYCLOTRON HEATING FACILITY UPGRADE AT DIII-D

    SciTech Connect

    S.G.E. PRONKO; S.W. DELAWARE; T.E. HARRIS; D. HOYT; D.H. KELLMAN; R.A. LEGG; M. LONTOC; A. NEREM; J.R. VALENTINE

    2000-11-01

    The DIII-D National Fusion Facility at General Atomics is completing the upgrade of its electron cyclotron heating (ECH) capability from the previous 3 MW at 110 GHz to 6 MW of generated microwave power. An 8.4 MW modulator/regulator (M/R) power system has been designed and constructed. Surplus hardware that was acquired from the Lawrence Livermore National Laboratory (LLNL) Mirror Fusion Test Facility (MFTF program) was used as part of the design foundation. The power system, with a nominal output of -80 kV and 80 A, can supply a pair of gyrotrons with up to 10 second long pulses that may or may not be modulated. The modulator/regulator was designed about the BBC CKQ200-4 tetrode, which was the key component acquired from the LLNL program. In order to meet the performance goals of the program, substantial design modifications were needed to be made on the grid driver amplifier and the closed-loop feedback regulator circuits. Also, a newly designed crowbar switch system, featuring a high speed, thyratron-like triggered gas switch, was implemented. The modulator/regulator performance to date has been demonstrated as having <0.06% peak-to-peak ripple and square wave modulation of 50% amplitude at 2 kHz. The key features of the design of the power system and its performance will be presented in this paper.

  14. Modelling and analysis of a high-performance Class D audio amplifier using unipolar pulse-width-modulation

    NASA Astrophysics Data System (ADS)

    Zhou, Zekun; Shi, Yue; Ming, Xin; Zhang, Bo; Li, Zhaoji; Chen, Zao

    2012-02-01

    A high-performance class D audio amplifier using unipolar pulse-width-modulation (PWM) with double-sided natural sampling is presented in this article. In order to comprehend and design the system properly, the class D audio amplifier is modelled and analysed. A wide range triangle-wave signal with good linearity and magnitude proportional to supply voltage is embedded in the proposed class D audio amplifier for maximum output power, high power supply rejection ratio (PSRR) and low total harmonic distortion (THD). Design results based on CSMC 0.5-µm 5-V complementary metal-oxide-semiconductor process demonstrate that the proposed class D audio amplifier can operate with supply voltage in the range 2.4-5.5 V and supports 2.8 W output power from a 5.5 V supply; the maximum efficiency is above 95%, the PSRR is -82 dB, the signal-to-noise ratio (SNR) is 97 dB and the total harmonic distortion plus noise (THD+N) is less than 0.1% between 20 and 20 kHz with output power 0.4 W; the quiescent current without load is 1.8 mA, and the shutdown current is 0.01 µA. The active area of the class-D audio power amplifier is 1.5 mm × 1.5 mm.

  15. Performance improvement of a large range metrological AFM through parasitic interference feedback artifacts removing by using laser multimode modulation method

    NASA Astrophysics Data System (ADS)

    Li, Qi; Gao, Sitian; Li, Wei; Lu, Mingzhen; Shi, Yushu

    2013-05-01

    A large range multi-functional metrological atomic force microscope based on optical beam deflection method has been set up at NIM one year ago. Being designed intended to make a traceable measurement of standard samples, the machine uses three axes stacked piezoceramic actuators, each axis with a pair of push-pull piezo operated at opposite phases to make orthogonal scanning with maximized dimensional up to 50×50×2mm3. The stage displacement is measured by homodyne interferometer framework in x,y,z direction, from which beams are aligned to intersect at cantilever tip to avoid Abbe error, an eight times optical path multiplier interferometer mirror is researched to enhance fringe resolution. There is also a new compact AFM head integrated with LD, quadrant PD, cantilever, optical path and microscope, the head uses special track lens group to guarantee laser spot focused and static on the back of the cantilever, no matter whether or not the cantilever have lateral movements; similarly, reflect beam also focused and static in the center of quadrant detector through convergence lens group, assumed no cantilever bending on vertical direction. Attribute to above design, the AFM have a resolution up to 0.5nm. In the paper, further improvement is described to reduce the influence of parasitic interference caused by reflection from sample surface using laser multimode modulation, the results shows metrological AFM have a better performance in measuring step, lateral pitch, line width, nanoroughness and other nanoscale structures.

  16. 200Gb/s 10-channel miniature optical interconnect transmitter module for high-performance computing (HPC)

    NASA Astrophysics Data System (ADS)

    Mohammed, Edris; Au, Hinmeng

    2010-02-01

    A major breakthrough to alleviating the interconnect bottleneck in intra cabinet system in HPC may happen by bringing optics directly to the processor package. In order to do so efficient and compact optical interconnect subassembly modules that utilize simple optical and electrical interfacing schemes are needed. In our current work the development of a novel 10-channel, miniature 7mm(W)x1.8mm(L)x3mm(H), optical interconnect transmitter subassembly module is described. The module consists of a high precision molded optical alignment unit with integrated microlens arrays, highspeed coplanar waveguide (CPW) electrical interfaces and a VCSEL (Vertical Cavity Surface Emitting Laser) array chip which is flip chip mounted. The module is designed to uniquely interface vertically with high-speed electrical I/O lines on a microprocessor style package or a motherboard to convert electrical signals to optical for transmission to other similar units using a standard (Multi-Terminal) MT style optical connector. We report on optical coupling efficiency, misalignment tolerance and high-speed electrical and optical measurements of the module. We have measured 40Gb/s electrical eye for the CPW interfaces on the module and 20Gb/s clear optical eyes for VCSEL assembled module from all the 10 channels to produce an aggregate transmitter bandwidth of 200Gb/s. We also measured 30Gb/s electrical and 20Gb/s optical eyes for the optical subassembly module that is bonded onto a microprocessor style package substrate.

  17. Module 3--School-Family-Community Connections. School Improvement Specialist Training Materials: Performance Standards, Improving Schools, and Literature Review

    ERIC Educational Resources Information Center

    Appalachia Educational Laboratory at Edvantia (NJ1), 2005

    2005-01-01

    The School Improvement Specialist Project prepared seven modules. School improvement specialists, as defined by the Appalachia Educational Laboratory at Edvantia, are change agents who work with schools to help them improve in the following areas so as to increase student achievement. These modules are intended to provide training materials for…

  18. Evaluating the Performance of a Battery Using Temperature and Voltage Profiles and a Battery-Resistor Circuit Module

    ERIC Educational Resources Information Center

    Sawyer, Bryan; Ji, Michelle; Gordon, Michael J.; Suppes, Galen J.

    2010-01-01

    An experimental learning module has been developed to study the mass and energy balance involved with operation of an AA Alkaline battery under a load current. An extension of the module allows evaluation of laboratory-assembled batteries using granular anodic/cathodic materials. The system allows load resistance to be varied and measures voltage…

  19. Rhesus Factor Modulation of Effects of Smoking and Age on Psychomotor Performance, Intelligence, Personality Profile, and Health in Czech Soldiers

    PubMed Central

    Flegr, Jaroslav; Geryk, Jan; Volný, Jindra; Klose, Jiří; Černochová, Dana

    2012-01-01

    Background Rhesus-positive and rhesus-negative persons differ in the presence-absence of highly immunogenic RhD protein on the erythrocyte membrane. This protein is a component of NH3 or CO2 pump whose physiological role is unknown. Several recent studies have shown that RhD positivity protects against effects of latent toxoplasmosis on motor performance and personality. It is not known, however, whether the RhD phenotype modifies exclusively the response of the body to toxoplasmosis or whether it also influences effects of other factors. Methodology/Principal Findings In the present cohort study, we searched for the effects of age and smoking on performance, intelligence, personality and self-estimated health and wellness in about 3800 draftees. We found that the positive effect of age on performance and intelligence was stronger in RhD-positive soldiers, while the negative effect of smoking on performance and intelligence was of similar size regardless of the RhD phenotype. The effect of age on four Cattell's personality factors, i.e., dominance (E), radicalism (Q1), self-sentiment integration (Q3), and ergic tension (Q4), and on Cloninger's factor reward dependency (RD) was stronger for RhD-negative than RhD-positive subjects, while the effect of smoking on the number of viral and bacterial diseases was about three times stronger for RhD-negative than RhD-positive subjects. Conclusions RhD phenotype modulates the influence not only of latent toxoplasmosis, but also of at least two other potentially detrimental factors, age and smoking, on human behavior and physiology. The negative effect of smoking on health (estimated on the basis of the self-rated number of common viral and bacterial diseases in the past year) was much stronger in RhD-negative than RhD-positive subjects. It is critically needed to confirm the differences in health response to smoking between RhD-positive and RhD-negative subjects by objective medical examination in future studies. PMID

  20. Linearization of the frequency sweep of a frequency-modulated continuous-wave semiconductor laser radar and the resulting ranging performance.

    PubMed

    Karlsson, C J; Olsson, F A

    1999-05-20

    The performance of a frequency-modulated continuous-wave (FMCW) semiconductor laser radar has been examined. Frequency modulation (linear chirp) has been studied experimentally in detail. To create a linear frequency sweep, we modified the modulating function according to the measured frequency response of the laser, using an arbitrary function generator. The measurements indicate the possibility of achieving a spectral width of the signal peak that is transform limited rather than limited by the frequency modulation response of the laser, which permits the use of a narrow detection bandwidth. The narrow width results in a relatively high signal-to-noise ratio for low output power and thus also in relatively long-range and high-range accuracy. We have performed measurements of a diffuse target to determine the performance of a test laser radar system. The maximum range, range accuracy, and speed accuracy for a semiconductor laser with an output power of 10 mW and a linewidth of 400 kHz are presented. The influence of the laser's output power and coherence length on the performance of a semiconductor-laser-based FMCW laser radar is discussed. PMID:18319935

  1. Low-Complexity, High-Performance Bandwidth Efficient Coding and Coded Modulation Techniques for Satellite and Space Communications

    NASA Technical Reports Server (NTRS)

    Costello, Daniel J., Jr.

    1993-01-01

    The semi-annual progress report for NASA grant NAG5-557 is presented. The report contains three papers concerning bandwidth efficient coding and coded modulation techniques for satellite and space communications.

  2. Innovative Characterization of Amorphous and Thin-Film Silicon for Improved Module Performance: 1 February 2005 - 31 July 2008

    SciTech Connect

    Taylor, P. C.; Williams, G. A.

    2009-09-01

    Electron spin resonance and nuclear magnetic resonance was done on amorphous silicon samples (modules with a-Si:H and a-SixGe1-x:H intrinsic layer) to study defects that contribute to Staebler-Wronski effect.

  3. Ontogeny of hypoxic modulation of cardiac performance and its allometry in the African clawed frog Xenopus laevis.

    PubMed

    Pan, T-C Francis; Burggren, Warren W

    2013-01-01

    The ontogeny of cardiac hypoxic responses, and how such responses may be modified by rearing environment, are poorly understood in amphibians. In this study, cardiac performance was investigated in Xenopus laevis from 2 to 25 days post-fertilization (dpf). Larvae were reared under either normoxia or moderate hypoxia (PO₂ = 110 mmHg), and each population was assessed in both normoxia and acute hypoxia. Heart rate (f(H)) of normoxic-reared larvae exhibited an early increase from 77 ± 1 beats min⁻¹ at 2 dpf to 153 ± 1 beats min⁻¹ at 4 dpf, followed by gradual decreases to 123 ± 3 beats min⁻¹ at 25 dpf. Stroke volume (SV), 6 ± 1 nl, and cardiac output (CO), 0.8 ± 0.1 μl min⁻¹, at 5 dpf both increased by more than 40-fold to 25 dpf with rapid larval growth (~30-fold increase in body mass). When exposed to acute hypoxia, normoxic-reared larvae increased f(H) and CO between 5 and 25 dpf. Increased SV in acute hypoxia, produced by increased end-diastolic volume (EDV), only occurred before 10 dpf. Hypoxic-reared larvae showed decreased acute hypoxic responses of EDV, SV and CO at 7 and 10 dpf. Over the period of 2-25 dpf, cardiac scaling with mass showed scaling coefficients of -0.04 (f(H)), 1.23 (SV) and 1.19 (CO), contrary to the cardiac scaling relationships described in birds and mammals. In addition, f(H) scaling in hypoxic-reared larvae was altered to a shallower slope of -0.01. Collectively, these results indicate that acute cardiac hypoxic responses develop before 5 dpf. Chronic hypoxia at a moderate level can not only modulate this cardiac reflex, but also changes cardiac scaling relationship with mass.

  4. Modulation of astrocytic mitochondrial function by dichloroacetate improves survival and motor performance in inherited amyotrophic lateral sclerosis.

    PubMed

    Miquel, Ernesto; Cassina, Adriana; Martínez-Palma, Laura; Bolatto, Carmen; Trías, Emiliano; Gandelman, Mandi; Radi, Rafael; Barbeito, Luis; Cassina, Patricia

    2012-01-01

    Mitochondrial dysfunction is one of the pathogenic mechanisms that lead to neurodegeneration in Amyotrophic Lateral Sclerosis (ALS). Astrocytes expressing the ALS-linked SOD1(G93A) mutation display a decreased mitochondrial respiratory capacity associated to phenotypic changes that cause them to induce motor neuron death. Astrocyte-mediated toxicity can be prevented by mitochondria-targeted antioxidants, indicating a critical role of mitochondria in the neurotoxic phenotype. However, it is presently unknown whether drugs currently used to stimulate mitochondrial metabolism can also modulate ALS progression. Here, we tested the disease-modifying effect of dichloroacetate (DCA), an orphan drug that improves the functional status of mitochondria through the stimulation of the pyruvate dehydrogenase complex activity (PDH). Applied to astrocyte cultures isolated from rats expressing the SOD1(G93A) mutation, DCA reduced phosphorylation of PDH and improved mitochondrial coupling as expressed by the respiratory control ratio (RCR). Notably, DCA completely prevented the toxicity of SOD1(G93A) astrocytes to motor neurons in coculture conditions. Chronic administration of DCA (500 mg/L) in the drinking water of mice expressing the SOD1(G93A) mutation increased survival by 2 weeks compared to untreated mice. Systemic DCA also normalized the reduced RCR value measured in lumbar spinal cord tissue of diseased SOD1(G93A) mice. A remarkable effect of DCA was the improvement of grip strength performance at the end stage of the disease, which correlated with a recovery of the neuromuscular junction area in extensor digitorum longus muscles. Systemic DCA also decreased astrocyte reactivity and prevented motor neuron loss in SOD1(G93A) mice. Taken together, our results indicate that improvement of the mitochondrial redox status by DCA leads to a disease-modifying effect, further supporting the therapeutic potential of mitochondria-targeted drugs in ALS.

  5. In Orbit Performance of Si Avalanche Photodiode Single Photon Counting Modules in the Geoscience Laser Altimeter System on ICESat

    NASA Technical Reports Server (NTRS)

    Sun, X.; Jester, P. L.; Palm, S. P.; Abshire, J. B.; Spinhime, J. D.; Krainak, M. A.

    2006-01-01

    Si avalanche photodiode (APD) single photon counting modules (SPCMs) are used in the Geoscience Laser Altimeter System (GLAS) on Ice, Cloud, anti land Elevation Satellite (ICESat), currently in orbit measuring Earth surface elevation and atmosphere backscattering. These SPCMs are used to measure cloud and aerosol backscatterings to the GLAS laser light at 532-nm wavelength with 60-70% quantum efficiencies and up to 15 millions/s maximum count rates. The performance of the SPCMs has been closely monitored since ICESat launch on January 12, 2003. There has been no measurable change in the quantum efficiency, as indicated by the average photon count rates in response to the background light from the sunlit earth. The linearity and the afterpulsing seen from the cloud and surface backscatterings profiles have been the same as those during ground testing. The detector dark count rates monitored while the spacecraft was in the dark side of the globe have increased almost linearly at about 60 counts/s per day due to space radiation damage. The radiation damage appeared to be independent of the device temperature and power states. There was also an abrupt increase in radiation damage during the solar storm in 28-30 October 2003. The observed radiation damage is a factor of two to three lower than the expected and sufficiently low to provide useful atmosphere backscattering measurements through the end of the ICESat mission. To date, these SPCMs have been in orbit for more than three years. The accumulated operating time to date has reached 290 days (7000 hours). These SPCMs have provided unprecedented receiver sensitivity and dynamic range in ICESat atmosphere backscattering measurements.

  6. Intraperitoneal injection of saline modulates hippocampal brain receptor complex levels but does not impair performance in the Morris Water Maze.

    PubMed

    Sase, Ajinkya; Khan, Deeba; Höger, Harald; Lubec, Gert

    2012-08-01

    The involvement of the hippocampus in pain has been demonstrated but key players, i.e. the major brain receptors have not been shown to be modulated by pain. It was therefore the aim of the study to show the concerted action and pattern of brain receptor complex levels in a non-invasive model of moderate pain. C57BL/6J mice were divided into four groups of 14 animals each: trained injected, trained non-injected, yoked injected and yoked non-injected. Animals were tested in the open field and the elevated plus maze for behavioural evaluation and cognitive functions were tested using the Morris Water Maze. Hippocampi were taken 6 h following sacrification. Membrane proteins were prepared by ultracentrifugation and run on blue native gels to keep the native state, blotted to membranes and western blotting was carried out using the primary antibodies against serotonin receptor 5HT1A, muscarinic acetylcholine receptor M1 (mAChR-M1), nicotinic acetylcholine receptor alpha7 (nAChR-alpha7), glutamate (AMPA) receptor (GluR1) and neurokinin receptor 1 (NK-1). There was no difference between performance in behaviour or in the MWM between groups. Brain receptor level changes involved all receptors given above. Pain affected mAChR-M1, GluR1 and NK-1 complex levels when yoked-injected were compared with yoked non-injected animals. Memory mechanisms affected mAChR-M1 complex levels when trained non-injected animals were compared with yoked non-injected controls. Taken together, the neurochemical basis for testing receptor agonists/antagonists on the role of pain and the hippocampus was generated that may be useful for interpretations of the role of this complex area in moderate pain.

  7. SU-D-19A-03: Monte Carlo Investigation of the Mobetron to Perform Modulated Electron Beam Therapy

    SciTech Connect

    Emam, I; Eldib, A; Hosini, M; AlSaeed, E; Ma, C

    2014-06-01

    Purpose: Modulated electron radiotherapy (MERT) has been proposed as a mean of delivering conformal dose to shallow tumors while sparing distal structures and surrounding tissues. In intraoperative radiotherapy (IORT) utilizing Mobetron, an applicator is placed as closely as possible to the suspected cancerous tissues to be treated. In this study we investigate the characteristics of Mobetron electron beams collimated by an in-house prospective electron multileaf collimator (eMLC) and its feasibility for MERT. Methods: IntraOp Mobetron™ dedicated to perform radiotherapy during surgery was used in the study. It provides several energies (6, 9 and 12 MeV). Dosimetry measurements were performed to obtain percentage depth dose curves (PDD) and profiles for a 10-cm diameter applicator using the PTW MP3/XS 3D-scanning system and the semiflex ion chamber. MCBEAM/MCSIM Monte Carlo codes were used for the treatment head simulation and phantom dose calculation. The design of an electron beam collimation by an eMLC attached to the Mobetron head was also investigated using Monte Carlo simulations. Isodose distributions resulting from eMLC collimated beams were compared to that collimated using cutouts. The design for our Mobetron eMLC is based on our previous experiences with eMLCs designed for clinical linear accelerators. For Mobetron the eMLC is attached to the end of a spacer-mounted rectangular applicator at 50 cm SSD. Steel will be used as the leaf material because other materials would be toxic and will not be suitable for intraoperative applications. Results: Good agreement (within 2%) was achieved between measured and calculated PDD curves and profiles for all available energies. Dose distributiosn provided by the eMLC showed reasonable agreement (∼3%/1mm) with those obtained by conventional cutouts. Conclusion: Monte Carlo simulations are capable of modeling Mobetron electron beams with a reliable accuracy. An eMLC attached to the Mobteron treatment head will

  8. Improvement of the performance of the twisted-nematic liquid-crystal display as a phase modulator.

    PubMed

    Ma, Baiheng; Yao, Baoli; Li, Ze; Ye, Tong

    2011-06-10

    A twisted-nematic liquid-crystal display (TN-LCD) placed between two linear polarizers (P) generally produces coupled intensity and phase modulations. For the purpose of phase-only modulation, quarter-wave plates (QWPs) are often used in front of or behind the LCD. In this paper, we demonstrate theoretically and experimentally the QWPs' effect on the modulation properties of the TN-LCD based on the general Jones matrix descriptions for all the devices, which circumvents the inconvenience of the traditional method on the basis of the TN-LCD's internal parameters. We prove that the phase modulation depth of the TN-LCD can be further increased in the configuration of P1-QWP1-LCD-QWP2-P2 with each component properly oriented, provided that the mean intensity transmission is decreased to a lower level. By observing the diffracted patterns of the Ronchi phase grating or blazed grating addressed onto the TN-LCD, we verify the validity of the proposed method. Improved reconstructed image quality from the kinoform loaded on the TN-LCD is obtained in this configuration. This approach is valuable when the TN-LCD is employed as a phase modulator, especially for the modern, thinner TN-LCD. PMID:21673760

  9. On the performances of Intensity Modulated Protons, RapidArc and Helical Tomotherapy for selected paediatric cases

    PubMed Central

    Fogliata, Antonella; Yartsev, Slav; Nicolini, Giorgia; Clivio, Alessandro; Vanetti, Eugenio; Wyttenbach, Rolf; Bauman, Glenn; Cozzi, Luca

    2009-01-01

    Background To evaluate the performance of three different advanced treatment techniques on a group of complex paediatric cancer cases. Methods CT images and volumes of interest of five patients were used to design plans for Helical Tomotherapy (HT), RapidArc (RA) and Intensity Modulated Proton therapy (IMP). The tumour types were: extraosseous, intrathoracic Ewing Sarcoma; mediastinal Rhabdomyosarcoma; metastastis of base of skull with bone, para-nasal and left eye infiltration from Nephroblastoma of right kidney; metastatic Rhabdomyosarcoma of the anus; Wilm's tumour of the left kidney with multiple liver metastases. Cases were selected for their complexity regardless the treatment intent and stage. Prescribed doses ranged from 18 to 53.2 Gy, with four cases planned using a Simultaneous Integrated Boost strategy. Results were analysed in terms of dose distributions and dose volume histograms. Results For all patients, IMP plans lead to superior sparing of organs at risk and normal healthy tissue, where in particular the integral dose is halved with respect to photon techniques. In terms of conformity and of spillage of high doses outside targets (external index (EI)), all three techniques were comparable; CI90% ranged from 1.0 to 2.3 and EI from 0 to 5%. Concerning target homogeneity, IMP showed a variance (D5%–D95%) measured on the inner target volume (highest dose prescription) ranging from 5.9 to 13.3%, RA from 5.3 to 11.8%, and HT from 4.0 to 12.2%. The range of minimum significant dose to the same target was: (72.2%, 89.9%) for IMP, (86.7%, 94.1%) for RA, and (79.4%, 94.8%) for HT. Similarly, for maximum significant doses: (103.8%, 109.4%) for IMP, (103.2%, 107.4%) for RA, and (102.4%, 117.2%) for HT. Treatment times (beam-on time) ranged from 123 to 129 s for RA and from 146 to 387 s for HT. Conclusion Five complex pediatric cases were selected as representative examples to compare three advanced radiation delivery techniques. While differences were noted

  10. SU-E-T-608: Performance Comparison of Four Commercial Treatment Planning Systems Applied to Intensity-Modulated Radiotherapy

    SciTech Connect

    Cao, Y; Li, R; Chi, Z

    2014-06-01

    Purpose: To compare the performances of four commercial treatment planning systems (TPS) used for the intensity-modulated radiotherapy (IMRT). Methods: Ten patients of nasopharyngeal (4 cases), esophageal (3 cases) and cervical (3 cases) cancer were randomly selected from a 3-month IMRT plan pool at one radiotherapy center. For each patient, four IMRT plans were newly generated by using four commercial TPS (Corvus, Monaco, Pinnacle and Xio), and then verified with Matrixx (two-dimensional array/IBA Company) on Varian23EX accelerator. A pass rate (PR) calculated from the Gamma index by OminiPro IMRT 1.5 software was evaluated at four plan verification standards (1%/1mm, 2%/2mm, 3%/3mm, 4%/4mm and 5%/5mm) for each treatment plan. Overall and multiple pairwise comparisons of PRs were statistically conducted by analysis of covariance (ANOVA) F and LSD tests among four TPSs. Results: Overall significant (p>0.05) differences of PRs were found among four TPSs with F test values of 3.8 (p=0.02), 21.1(>0.01), 14.0 (>0.01), 8.3(>0.01) at standards of 1%/1mm to 4%/4mm respectively, except at 5%/5mm standard with 2.6 (p=0.06). All means (standard deviation) of PRs at 3%/3mm of 94.3 ± 3.3 (Corvus), 98.8 ± 0.8 (Monaco), 97.5± 1.7 (Pinnacle), 98.4 ± 1.0 (Xio) were above 90% and met clinical requirement. Multiple pairwise comparisons had not demonstrated a consistent low or high pattern on either TPS. Conclusion: Matrixx dose verification results show that the validation pass rates of Monaco and Xio plans are relatively higher than those of the other two; Pinnacle plan shows slight higher pass rate than Corvus plan; lowest pass rate was achieved by the Corvus plan among these four kinds of TPS.

  11. E-learning module on chronic low back pain in older adults: evidence of effect on medical student objective structured clinical examination performance.

    PubMed

    Weiner, Debra K; Morone, Natalia E; Spallek, Heiko; Karp, Jordan F; Schneider, Michael; Washburn, Carol; Dziabiak, Michael P; Hennon, John G; Elnicki, D Michael

    2014-06-01

    The Institute of Medicine has highlighted the urgent need to close undergraduate and graduate educational gaps in treating pain. Chronic low back pain (CLBP) is one of the most common pain conditions, and older adults are particularly vulnerable to potential morbidities associated with misinformed treatment. An e-learning case-based interactive module was developed at the University of Pittsburgh Center of Excellence in Pain Education, one of 12 National Institutes of Health-designated centers, to teach students important principles for evaluating and managing CLBP in older adults. A team of six experts in education, information technology, pain management, and geriatrics developed the module. Teaching focused on common errors, interactivity, and expert modeling and feedback. The module mimicked a patient encounter using a standardized patient (the older adult with CLBP) and a pain expert (the patient provider). Twenty-eight medical students were not exposed to the module (Group 1) and 27 were exposed (Group 2). Their clinical skills in evaluating CLBP were assessed using an objective structured clinical examination (OSCE). Mean scores were 62.0 ± 8.6 for Group 1 and 79.5 ± 10.4 for Group 2 (P < .001). Using an OSCE pass-fail cutoff score of 60%, 17 of 28 Group 1 students (60.7%) and 26 of 27 Group 2 students (96.3%) passed. The CLBP OSCE was one of 10 OSCE stations in which students were tested at the end of a Combined Ambulatory Medicine and Pediatrics Clerkship. There were no between-group differences in performance on eight of the other nine OSCE stations. This module significantly improved medical student clinical skills in evaluating CLBP. Additional research is needed to ascertain the effect of e-learning modules on more-advanced learners and on improving the care of older adults with CLBP.

  12. Usage of NASA's Near Real-Time Solar and Meteorological Data for Monitoring Building Energy Systems Using RETScreen International's Performance Analysis Module

    NASA Technical Reports Server (NTRS)

    Stackhouse, Paul W., Jr.; Charles, Robert W.; Chandler, William S.; Hoell, James M.; Westberg, David; Zhang, Taiping; Ziegler, Urban; Leng, Gregory J.; Meloche, Nathalie; Bourque, Kevin

    2012-01-01

    This paper describes building energy system production and usage monitoring using examples from the new RETScreen Performance Analysis Module, called RETScreen Plus. The module uses daily meteorological (i.e., temperature, humidity, wind and solar, etc.) over a period of time to derive a building system function that is used to monitor building performance. The new module can also be used to target building systems with enhanced technologies. If daily ambient meteorological and solar information are not available, these are obtained over the internet from NASA's near-term data products that provide global meteorological and solar information within 3-6 days of real-time. The accuracy of the NASA data are shown to be excellent for this purpose enabling RETScreen Plus to easily detect changes in the system function and efficiency. This is shown by several examples, one of which is a new building at the NASA Langley Research Center that uses solar panels to provide electrical energy for building energy and excess energy for other uses. The system shows steady performance within the uncertainties of the input data. The other example involves assessing the reduction in energy usage by an apartment building in Sweden before and after an energy efficiency upgrade. In this case, savings up to 16% are shown.

  13. Impact of Active Teaching Methods Implemented on Therapeutic Chemistry Module: Performance and Impressions of First-Year Pharmacy Students

    ERIC Educational Resources Information Center

    Derfoufi, Sanae; Benmoussa, Adnane; El Harti, Jaouad; Ramli, Youssef; Taoufik, Jamal; Chaouir, Souad

    2015-01-01

    This study investigates the positive impact of the Case Method implemented during a 4- hours tutorial in "therapeutic chemistry module." We view the Case Method as one particular approach within the broader spectrum of problem based or inquiry based learning approaches. Sixty students were included in data analysis. A pre-test and…

  14. Comparison of the performance between portal dosimetry and a commercial two-dimensional array system on pretreatment quality assurance for volumetric-modulated arc and intensity-modulated radiation therapy

    NASA Astrophysics Data System (ADS)

    Kim, Yon-Lae; Chung, Jin-Beom; Kim, Jae-Sung; Lee, Jeong-Woo; Choi, Kyoung-Sik

    2014-04-01

    The aim of this study was to compare the dosimetric performance and to evaluate the pretreatment quality assurance (QA) of a portal dosimetry and a commercial two-dimensional (2-D) array system. In the characteristics comparison study, the measured values for the dose linearity, dose rate response, reproducibility, and field size dependence for 6-MV photon beams were analyzed for both detector systems. To perform the qualitative evaluations of the 10 IMRT and the 10 VMAT plans, we used the Gamma index for quantifying the agreement between calculations and measurements. The performance estimates for both systems show that overall, minimal differences in the dosimetric characteristics exist between the Electron portal imaging device (EPID) and 2-D array system. In the qualitative analysis for pretreatment quality assurance, the EPID and 2-D array system yield similar passing rate results for the majority of clinical Intensity-modulated radiation therapy (IMRT) and Volumetric-modulated arc therapy (VMAT) cases. These results were satisfactory for IMRT and VMAT fields and were within the acceptable criteria of γ%≤1, γ avg <0.5. The EPDI and the 2-D array systems showed comparable dosimetric results. In this study, the results revealed both systems to be suitable for patient-specific QA measurements for IMRT and VMAT. We conclude that, depending on the status of clinic, both systems can be used interchangeably for routine pretreatment QA.

  15. Feedback-Related ERP Components Are Modulated by Social Distance during Non-Contingent Evaluation of Someone Else’s Performance

    PubMed Central

    2016-01-01

    Performance monitoring depends on cortical structures that are also activated in vicarious monitoring. While many experiments have shown that vicarious and on-line monitoring have a similar basis, most such experiments have focused on simple tasks. In order to assess the effect of non-contingent feedback on vicarious monitoring, 23 young volunteer adults were evaluated: in one session, they performed a rule-based category formation task, receiving no feedback on their performance. In a second session, Event Related Potentials (ERPs) were obtained while participants passively reviewed performances attributed to themselves and peers they had previously rated as either socially close or distant. Feedback Related Negativity (FRN) and Feedback Related P300 (fP300) components were analyzed with respect to feedback valence and agent. Results show that both components can be elicited through non-contingent feedback related to prior performance. In addition, FRN waves are modulated by the valence of the feedback, and fP300 is modulated by the agent to whom performance feedback is attributed. This experiment constitutes a novel approach to the evaluation of ERP correlates of vicarious monitoring through non-contingent feedback and its relations to empathy processing. PMID:27232887

  16. Dietary nitrate modulates cerebral blood flow parameters and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation.

    PubMed

    Wightman, Emma L; Haskell-Ramsay, Crystal F; Thompson, Kevin G; Blackwell, Jamie R; Winyard, Paul G; Forster, Joanne; Jones, Andrew M; Kennedy, David O

    2015-10-01

    Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and increase regional perfusion in the brain. The current study assessed the effects of dietary nitrate on cognitive performance and prefrontal cortex cerebral blood-flow (CBF) parameters in healthy adults. In this randomised, double-blind, placebo-controlled, parallel-groups study, 40 healthy adults received either placebo or 450 ml beetroot juice (~5.5 mmol nitrate). Following a 90 minute drink/absorption period, participants performed a selection of cognitive tasks that activate the frontal cortex for 54 min. Near-Infrared Spectroscopy (NIRS) was used to monitor CBF and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated-haemoglobin, in the frontal cortex throughout. The bioconversion of nitrate to nitrite was confirmed in plasma by ozone-based chemi-luminescence. Dietary nitrate modulated the hemodynamic response to task performance, with an initial increase in CBF at the start of the task period, followed by consistent reductions during the least demanding of the three tasks utilised. Cognitive performance was improved on the serial 3s subtraction task. These results show that single doses of dietary nitrate can modulate the CBF response to task performance and potentially improve cognitive performance, and suggest one possible mechanism by which vegetable consumption may have beneficial effects on brain function. PMID:26037632

  17. Involvement of the TRPV1 channel in the modulation of spontaneous locomotor activity, physical performance and physical exercise-induced physiological responses

    PubMed Central

    Hudson, A.S.R.; Kunstetter, A.C.; Damasceno, W.C.; Wanner, S.P.

    2016-01-01

    Physical exercise triggers coordinated physiological responses to meet the augmented metabolic demand of contracting muscles. To provide adequate responses, the brain must receive sensory information about the physiological status of peripheral tissues and organs, such as changes in osmolality, temperature and pH. Most of the receptors involved in these afferent pathways express ion channels, including transient receptor potential (TRP) channels, which are usually activated by more than one type of stimulus and are therefore considered polymodal receptors. Among these TRP channels, the TRPV1 channel (transient receptor potential vanilloid type 1 or capsaicin receptor) has well-documented functions in the modulation of pain sensation and thermoregulatory responses. However, the TRPV1 channel is also expressed in non-neural tissues, suggesting that this channel may perform a broad range of functions. In this review, we first present a brief overview of the available tools for studying the physiological roles of the TRPV1 channel. Then, we present the relationship between the TRPV1 channel and spontaneous locomotor activity, physical performance, and modulation of several physiological responses, including water and electrolyte balance, muscle hypertrophy, and metabolic, cardiovascular, gastrointestinal, and inflammatory responses. Altogether, the data presented herein indicate that the TPRV1 channel modulates many physiological functions other than nociception and thermoregulation. In addition, these data open new possibilities for investigating the role of this channel in the acute effects induced by a single bout of physical exercise and in the chronic effects induced by physical training. PMID:27191606

  18. Involvement of the TRPV1 channel in the modulation of spontaneous locomotor activity, physical performance and physical exercise-induced physiological responses.

    PubMed

    Hudson, A S R; Kunstetter, A C; Damasceno, W C; Wanner, S P

    2016-01-01

    Physical exercise triggers coordinated physiological responses to meet the augmented metabolic demand of contracting muscles. To provide adequate responses, the brain must receive sensory information about the physiological status of peripheral tissues and organs, such as changes in osmolality, temperature and pH. Most of the receptors involved in these afferent pathways express ion channels, including transient receptor potential (TRP) channels, which are usually activated by more than one type of stimulus and are therefore considered polymodal receptors. Among these TRP channels, the TRPV1 channel (transient receptor potential vanilloid type 1 or capsaicin receptor) has well-documented functions in the modulation of pain sensation and thermoregulatory responses. However, the TRPV1 channel is also expressed in non-neural tissues, suggesting that this channel may perform a broad range of functions. In this review, we first present a brief overview of the available tools for studying the physiological roles of the TRPV1 channel. Then, we present the relationship between the TRPV1 channel and spontaneous locomotor activity, physical performance, and modulation of several physiological responses, including water and electrolyte balance, muscle hypertrophy, and metabolic, cardiovascular, gastrointestinal, and inflammatory responses. Altogether, the data presented herein indicate that the TPRV1 channel modulates many physiological functions other than nociception and thermoregulation. In addition, these data open new possibilities for investigating the role of this channel in the acute effects induced by a single bout of physical exercise and in the chronic effects induced by physical training. PMID:27191606

  19. Involvement of the TRPV1 channel in the modulation of spontaneous locomotor activity, physical performance and physical exercise-induced physiological responses.

    PubMed

    Hudson, A S R; Kunstetter, A C; Damasceno, W C; Wanner, S P

    2016-01-01

    Physical exercise triggers coordinated physiological responses to meet the augmented metabolic demand of contracting muscles. To provide adequate responses, the brain must receive sensory information about the physiological status of peripheral tissues and organs, such as changes in osmolality, temperature and pH. Most of the receptors involved in these afferent pathways express ion channels, including transient receptor potential (TRP) channels, which are usually activated by more than one type of stimulus and are therefore considered polymodal receptors. Among these TRP channels, the TRPV1 channel (transient receptor potential vanilloid type 1 or capsaicin receptor) has well-documented functions in the modulation of pain sensation and thermoregulatory responses. However, the TRPV1 channel is also expressed in non-neural tissues, suggesting that this channel may perform a broad range of functions. In this review, we first present a brief overview of the available tools for studying the physiological roles of the TRPV1 channel. Then, we present the relationship between the TRPV1 channel and spontaneous locomotor activity, physical performance, and modulation of several physiological responses, including water and electrolyte balance, muscle hypertrophy, and metabolic, cardiovascular, gastrointestinal, and inflammatory responses. Altogether, the data presented herein indicate that the TPRV1 channel modulates many physiological functions other than nociception and thermoregulation. In addition, these data open new possibilities for investigating the role of this channel in the acute effects induced by a single bout of physical exercise and in the chronic effects induced by physical training.

  20. Review of PV module performance at DOE/MIT Lincoln Laboratory test sites during the period 1977 to 1982

    SciTech Connect

    Forman, S E; Themelis, M P

    1982-01-01

    During the years 1977 to 1982, over 11,000 photovoltaic (PV) modules have been placed at experimental PV power generating systems in a number of field test sites in the United States. Prominent among these are a 100-kW system at Natural Bridges National Monument in Utah, a 25-kWp system at Mead, Nebraska, and a 15-kW system at Bryan, Ohio. Through a program of periodic surveillance, measurements, and inspections at the aforementioned sites, electrically failed modules were located, removed and analyzed during this six-year period. The principal causes of failure were: (1) cells cracked due to weathering or internal module stresses, (2) failed solder joints, (3) interconnects not soldered to rear sides of cells at assembly, (4) cells or interconnects electrically shorted to metallic substrates, and (5) broken or split interconnects. Details and photographs of many of the different types of failures are presented and some of the analysis techniques used to locate the failures are described.

  1. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation. Control modules -- Volume 1, Revision 4

    SciTech Connect

    Landers, N.F.; Petrie, L.M.; Knight, J.R.

    1995-04-01

    SCALE--a modular code system for Standardized Computer Analyses Licensing Evaluation--has been developed by Oak Ridge National Laboratory at the request of the US Nuclear Regulatory Commission. The SCALE system utilizes well-established computer codes and methods within standard analysis sequences that (1) allow an input format designed for the occasional user and/or novice, (2) automate the data processing and coupling between modules, and (3) provide accurate and reliable results. System development has been directed at problem-dependent cross-section processing and analysis of criticality safety, shielding, heat transfer, and depletion/decay problems. Since the initial release of SCALE in 1980, the code system has been heavily used for evaluation of nuclear fuel facility and package designs. This revision documents Version 4.2 of the system. This manual is divided into three volumes: Volume 1--for the control module documentation, Volume 2--for the functional module documentation, and Volume 3 for the documentation of the data libraries and subroutine libraries.

  2. A high performance all-organic flexural piezo-FET and nanogenerator via nanoscale soft-interface strain modulation.

    PubMed

    Dhakras, Dipti; Gawli, Yogesh; Chhatre, Shraddha; Wadgaonkar, Prakash; Ogale, Satishchandra

    2014-11-01

    Flexural strain fields are encountered in a wide variety of situations and invite novel device designs for their effective use in sensing, actuating, as well as energy harvesting (nanogenerator) applications. In this work we demonstrate an interesting all-organic device design comprising an electrospun P(VDF-TrFE) fiber-mat built directly on a conducting PANI film, which is also grown on a flexible PET substrate, for flexural piezo-FET and nanogenerator applications. Orders of magnitude stronger modulation of electrical transport in PANI film is realized in this device as compared to the case of a similar device but with a uniform spin-coated P(VDF-TrFE) film. We find that in the flexural mode of operation, the interaction between the laterally modulated nanoscale strain field distributions created by the fibers and the applied coherent strain field strongly influences the carrier transport in PANI. The transport modulation is suggested to occur due to strain-induced conformational changes in P(VDF-TrFE) leading to changes in carrier localization-delocalization. We further show that the fiber-mat based device system also works as an efficient nanogenerator capable of delivering power for low power applications.

  3. Optimized laser patterning for high performance Cu(In,Ga)Se2 thin-film solar modules

    NASA Astrophysics Data System (ADS)

    Burn, Andreas; Muralt, Martin; Witte, Reiner; Buecheler, Stephan; Nishiwaki, Shiro; Krainer, Lukas; Spuehler, Gabriel J.; Romano, Valerio

    2014-03-01

    The thin-film solar cell market has seen a period of consolidation during the last years and many involved companies were forced to stop production due to increasing price pressure from competing cell technologies. Today, thin-film solar industry is gaining momentum again. Especially Cu(In,Ga)Se2 technology evolves at high pace fired by recently achieved record efficiencies of 20.4 percent on flexible polyimide substrate [1] and 20.8 percent on glass substrate [2]. Fresh companies are preparing market entry with matured products and manufacturing technology suitable for high-volume and high-throughput production. Among these key-enabling technologies is laser patterning for cell-to-cell interconnects. Several research groups worked on efficient and reliable laser processes that are now ready for the industrial assessment. Here we present a set of work-horse processes for P1, P2 and P3 scribing of CIGS cells on glass substrate. Optimized parameters are presented for 532 nm and 1064 nm using 50 ps pulses from an all-in-fiber laser system. We further demonstrate the successful realization of functional 8-cell modules with a reduced "dead-zone" width of 70±5 μm and high efficiencies. The certified efficiency of 16.6 percent for our low-dead-zone champion module confirms the observation that shrinking of interconnects has no adverse effects on their electrical quality.

  4. Static internal performance of a single-engine onaxisymmetric-nozzle vaned-thrust-reverser design with thrust modulation capabilities

    NASA Technical Reports Server (NTRS)

    Leavitt, L. D.; Burley, J. R., II

    1985-01-01

    An investigation has been conducted at wind-off conditions in the stati-test facility of the Langley 16-Foot Transonic Tunnel. The tests were conducted on a single-engine reverser configuration with partial and full reverse-thrust modulation capabilities. The reverser design had four ports with equal areas. These ports were angled outboard 30 deg from the vertical impart of a splay angle to the reverse exhaust flow. This splaying of reverser flow was intended to prevent impingement of exhaust flow on empennage surfaces and to help avoid inlet reingestion of exhaust gas when the reverser is integrated into an actual airplane configuration. External vane boxes were located directly over each of the four ports to provide variation of reverser efflux angle from 140 deg to 26 deg (measured forward from the horizontal reference axis). The reverser model was tested with both a butterfly-type inner door and an internal slider door to provide area control for each individual port. In addition, main nozzle throat area and vector angle were varied to examine various methods of modulating thrust levels. Other model variables included vane box configuration (four or six vanes per box), orientation of external vane boxes with respect to internal port walls (splay angle shims), and vane box sideplates. Nozzle pressure ratio was varied from 2.0 approximately 7.0.

  5. Determining PHEV Performance Potential – User and Environmental Influences on A123 Systems’ Hymotion™ Plug-In Conversion Module for the Toyota Prius

    SciTech Connect

    John G. Smart; Huang Iu

    2009-05-01

    A123Systems’s HymotionTM L5 Plug-in Conversion Module (PCM) is a supplemental battery system that converts the Toyota Prius hybrid electric vehicle (HEV) into a plug-in hybrid electric vehicle (PHEV). The Hymotion system uses a lithium ion battery pack with 4.5 kWh of useable energy capacity and recharges by plugging into a standard 110/120V outlet. The system is designed to more than double the Prius fuel efficiency for 30-50km of charge depleting range. This paper will cover efforts by A123 Systems and the Idaho National Laboratory in studying the on-road performance of this PHEV fleet. The performance potentials of various fleets will be compared in order to determine the major influences on overall performance.

  6. A novel heterocyclic compound targeting the dopamine transporter improves performance in the radial arm maze and modulates dopamine receptors D1-D3.

    PubMed

    Saroja, Sivaprakasam R; Aher, Yogesh D; Kalaba, Predrag; Aher, Nilima Y; Zehl, Martin; Korz, Volker; Subramaniyan, Saraswathi; Miklosi, Andras G; Zanon, Lisa; Neuhaus, Winfried; Höger, Harald; Langer, Thierry; Urban, Ernst; Leban, Johann; Lubec, Gert

    2016-10-01

    A series of compounds targeting the dopamine transporter (DAT) haS been shown to improve memory performance most probably by re-uptake inhibition. Although specific DAT inhibitors are available, there is limited information about specificity, mechanism and in particular the effect on dopamine receptors. It was therefore the aim of the study to test the DAT inhibitor 4-(diphenyl-methanesulfinylmethyl)-2-methyl-thiazole (code: CE-111), synthetized in our laboratory for the specificity to target DAT, for the effects upon spatial memory and for induced dopamine receptor modulation. Re-uptake inhibition was tested for DAT (IC50=3.2μM), serotonin transporter, SERT (IC50=272291μM) and noradrenaline transporter, NET (IC50=174μM). Spatial memory was studied in the radial arm maze (RAM) in male Sprague-Dawley rats that were intraperitoneally injected with CE-111 (1 or 10mg/kg body weight). Performance in the RAM was improved using 1 and 10mg/kg body weight of CE-111. Training and treatment effects on presynaptic, postsynaptic and extrasynaptic D1 and D2- receptors and dopamine receptor containing complexes as well as on activated DAT were observed. CE-111 was crossing the blood-brain barrier comparable to modafinil and was identified as effective to improve memory performance in the RAM. Dopamine re-uptake inhibition along with modulations in dopamine receptors are proposed as potential underlying mechanisms. PMID:27288589

  7. Linear modulator

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A study of frequency division multiplexing (FDM) systems was made for the purpose of determining the system performance that can be obtained with available state of the art components. System performance was evaluated on the basis of past experience, system analysis, and component evaluation. The system study was specifically directed to the area of FDM systems using subcarrier channel frequencies from 4 kHz to 200 kHz and channel information bandwidths of dc to 1, 2, 4, 8, and 16 kHz. The evaluation also assumes that the demodulation will be from a tape recorder which produces frequency modulation of + or - 1% on the signal due to the tape recorder wow and flutter. For the modulation system it is assumed that the pilot and carrier channel frequencies are stable to within + or - .005% and that the FM on the channel carriers is negligible. The modulator system was evaluated for the temperature range of -20 degree to +85 degree while the demodulator system was evaluated for operation at room temperature.

  8. Dual-Pulse Pulse Position Modulation (DPPM) for Deep-Space Optical Communications: Performance and Practicality Analysis

    NASA Technical Reports Server (NTRS)

    Li, Jing; Hylton, Alan; Budinger, James; Nappier, Jennifer; Downey, Joseph; Raible, Daniel

    2012-01-01

    Due to its simplicity and robustness against wavefront distortion, pulse position modulation (PPM) with photon counting detector has been seriously considered for long-haul optical wireless systems. This paper evaluates the dual-pulse case and compares it with the conventional single-pulse case. Analytical expressions for symbol error rate and bit error rate are first derived and numerically evaluated, for the strong, negative-exponential turbulent atmosphere; and bandwidth efficiency and throughput are subsequently assessed. It is shown that, under a set of practical constraints including pulse width and pulse repetition frequency (PRF), dual-pulse PPM enables a better channel utilization and hence a higher throughput than it single-pulse counterpart. This result is new and different from the previous idealistic studies that showed multi-pulse PPM provided no essential information-theoretic gains than single-pulse PPM.

  9. Human Development Student Modules.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This set of 61 student learning modules deals with various topics pertaining to human development. The modules, which are designed for use in performance-based vocational education programs, each contain the following components: an introduction for the student, a performance objective, a variety of learning activities, content information, a…

  10. Comparison of the performance of forward fill/flush and reverse fill/flush flow modulation in comprehensive two-dimensional gas chromatography.

    PubMed

    Krupčík, Jan; Gorovenko, Roman; Špánik, Ivan; Sandra, Pat; Giardina, Matthew

    2016-09-30

    The performances of forward flow fill and flush (FFF) and of reverse flow fill and flush (RFF) in flow modulated comprehensive two-dimensional gas chromatography (GC×GC) using the same volume of the sampling channel have been studied and compared. Sample models include a reference mixture of hydrocarbons at low concentration, a petroleum reformate product and the essential oil of Rosa damascena Miller. The latter samples contain solutes in different concentrations but some up to 30% allowing to study overloading phenomena in detail. For solutes injected at low quantity, the performance of FFF and RFF is similar. For solutes present in a sample at high quantity, RFF guarantees less broadening and spreading resulting in better quantitation. PMID:27614731

  11. Comparison of the performance of forward fill/flush and reverse fill/flush flow modulation in comprehensive two-dimensional gas chromatography.

    PubMed

    Krupčík, Jan; Gorovenko, Roman; Špánik, Ivan; Sandra, Pat; Giardina, Matthew

    2016-09-30

    The performances of forward flow fill and flush (FFF) and of reverse flow fill and flush (RFF) in flow modulated comprehensive two-dimensional gas chromatography (GC×GC) using the same volume of the sampling channel have been studied and compared. Sample models include a reference mixture of hydrocarbons at low concentration, a petroleum reformate product and the essential oil of Rosa damascena Miller. The latter samples contain solutes in different concentrations but some up to 30% allowing to study overloading phenomena in detail. For solutes injected at low quantity, the performance of FFF and RFF is similar. For solutes present in a sample at high quantity, RFF guarantees less broadening and spreading resulting in better quantitation.

  12. Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation

    NASA Technical Reports Server (NTRS)

    Wang, C.-W.; Stark, W.

    2005-01-01

    This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.

  13. High-Performance and Omnidirectional Thin-Film Amorphous Silicon Solar Cell Modules Achieved by 3D Geometry Design.

    PubMed

    Yu, Dongliang; Yin, Min; Lu, Linfeng; Zhang, Hanzhong; Chen, Xiaoyuan; Zhu, Xufei; Che, Jianfei; Li, Dongdong

    2015-11-01

    High-performance thin-film hydrogenated amorphous silicon solar cells are achieved by combining macroscale 3D tubular substrates and nanoscaled 3D cone-like antireflective films. The tubular geometry delivers a series of advantages for large-scale deployment of photovoltaics, such as omnidirectional performance, easier encapsulation, decreased wind resistance, and easy integration with a second device inside the glass tube. PMID:26418573

  14. Performance improvement of phase-generated carrier method by eliminating laser-intensity modulation for optical seismometer

    NASA Astrophysics Data System (ADS)

    Shi, Qingping; Tian, Qian; Wang, Liwei; Tian, Changdong; Zhang, Huayong; Zhang, Min; Liao, Yanbiao; Wang, Honghua; Zeng, Xiang; Huang, Longjun

    2010-02-01

    An improved demodulation method for the phase-generated carrier (PGC) system by eliminating laser-intensity modulation (LIM) is proposed. The influence of LIM is analyzed theoretically and experimentally. Two parameters are used to describe the effect of LIM: the LIM coefficient (LIMC) and the LIM phase delay (LIMPD). Good stability of the LIMC and LIMPD is confirmed by experimentation with an actual system. The demodulation signal using the traditional method has a much greater higher harmonic component than the improved method due to LIM. The increase of the signal-to-total-harmonic ratio (SHR) using the improved method is >23 dB, and there is a corresponding improvement of 19 dB to the signal to noise and distortion (SINAD) and signal-to-noise ratio (SNR). A new prototype system using the improved PGC method for marine seismic sensing capable of demodulating multiple channels in parallel, simultaneously, is demonstrated. The SHR is stable at 56 dB when the LIMC is <0.5. Similar results are obtained for the SINAD and SNR. The demodulated signal's upper limit is ~100 rad at 100 Hz and 12 rad at 1 kHz, giving a dynamic range reaching 130 dB at 100 Hz. The system's SINAD is stable within 1 dB, whereas the SHR is stable within 2 dB in field application.

  15. Biological Interactions and Simulated Climate Change Modulates the Ecophysiological Performance of Colobanthus quitensis in the Antarctic Ecosystem

    PubMed Central

    Torres-Díaz, Cristian; Gallardo-Cerda, Jorge; Lavin, Paris; Oses, Rómulo; Carrasco-Urra, Fernando; Atala, Cristian; Acuña-Rodríguez, Ian S.; Convey, Peter; Molina-Montenegro, Marco A.

    2016-01-01

    Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09′ S), and Lagotellerie Island in the Antarctic Peninsula (65°53′ S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios. PMID:27776181

  16. Report on the Field Performance of A123Systems’s HymotionTM Plug-in Conversion Module for the Toyota Prius

    SciTech Connect

    Huang Iu; John Smart

    2009-04-01

    A123Systems’s HymotionTM L5 Plug-in Conversion Module (PCM) is a supplemental battery system that converts the Toyota Prius hybrid electric vehicle (HEV) into a plug-in hybrid electric vehicle (PHEV). The Hymotion system uses a lithium ion battery pack with 4.5 kWh of useable energy capacity. It recharges by plugging into a standard 110/120V outlet. The system is designed to more than double the Prius fuel efficiency for 30-40 miles of charge depleting range. If the Hymotion pack is fully depleted, the Prius operates as a normal HEV in charge sustaining mode. The Hymotion L5 PCM is the first commercially available aftermarket product complying with CARB emissions and NHTSA impact standards. Since 2006, over 50 initial production Hymotion Plug-in Conversion Modules have been installed in private fleet vehicles across the United States and Canada. With the help of the Idaho National Laboratory, which conducts the U.S. Department of Energy’s (DOE) Advanced Vehicle Testing Activity (AVTA), A123Systems collects real-time vehicle data from each fleet vehicle using on-board data loggers. These data are analyzed to determine vehicle performance. This paper presents the results of this field evaluation. Data to be presented includes the L5 Prius charge depleting range, gasoline fuel efficiency, and electrical energy efficiency. Effects of driving conditions, driving style, and charging patterns on fuel efficiency are also presented. Data show the Toyota Prius equipped with the Hymotion Plug-in Conversion Module is capable of achieving over 100 mpg in certain driving conditions when operating in charge depleting mode.

  17. Both a Nicotinic Single Nucleotide Polymorphism (SNP) and a Noradrenergic SNP Modulate Working Memory Performance when Attention Is Manipulated

    ERIC Educational Resources Information Center

    Greenwood, Pamela M.; Sundararajan, Ramya; Lin, Ming-Kuan; Kumar, Reshma; Fryxell, Karl J.; Parasuraman, Raja

    2009-01-01

    We investigated the relation between the two systems of visuospatial attention and working memory by examining the effect of normal variation in cholinergic and noradrenergic genes on working memory performance under attentional manipulation. We previously reported that working memory for location was impaired following large location precues,…

  18. Activities in the frontal cortex and gait performance are modulated by preparation. An fNIRS study.

    PubMed

    Suzuki, Mitsuo; Miyai, Ichiro; Ono, Takeshi; Kubota, Kisou

    2008-01-15

    Neural activities in the primary motor cortex and supplementary motor area increase during the preparation as well as execution of voluntary movements of the hand and foot. However, there are few studies concerning preparatory activities of the brain preceding walking performance. We investigated how a verbal instruction "ready" before walking affected cortical activations and walking performances using a functional near-infrared spectroscopy. Seven healthy subjects performed two locomotor tasks on a treadmill with a verbal instruction "ready" before the treadmill was started (prepared walking; PW) and without it (simple walking; SW). Cadence was smaller and stride length was longer in PW than in SW. Increases of oxygenated hemoglobin (oxyHb) in the frontal regions especially in the prefrontal and premotor cortices were greater in PW than in SW both during the preparation and walking periods. These results suggested that preparation for walking cued by a verbal instruction enhanced frontal activations both during the preparation and execution of walking as well as walking performance. PMID:17950626

  19. Brain serotonergic and dopaminergic modulators, perceptual responses and endurance exercise performance following caffeine co-ingested with a high fat meal in trained humans

    PubMed Central

    2010-01-01

    Background The present study examined putative modulators and indices of brain serotonergic and dopaminergic function, perceptual responses, and endurance exercise performance following caffeine co-ingested with a high fat meal. Methods Trained humans (n = 10) performed three constant-load cycling tests at 73% of maximal oxygen uptake (VO2max) until exhaustion at 10°C remove space throughout. Prior to the first test, subjects consumed a 90% carbohydrate meal (Control trial) and for the remaining two tests, a 90% fat meal with (FC trial) and without (F trial) caffeine. Results Time to exhaustion was not different between the F and FC trials (P > 0.05); [Control trial: 116(88-145) min; F trial: 122(96-144) min; FC trial: 127(107-176) min]. However, leg muscular discomfort during exercise was significantly lower on the FC relative to F trial (P < 0.01). There were no significant differences between F and FC trials in key modulators and indices of brain serotonergic (5-HT) and dopaminergic (DA) function [(i.e. plasma free and total tryptophan (Trp), tyrosine (Tyr), large neutral amino acids (LNAA), Trp:LNAA ratio, free-Trp:Tyr ratio, total Trp:Tyr ratio, and plasma prolactin] (P > 0.05) with the exception of plasma free-Trp:LNAA ratio which was higher at 90 min and at exhaustion during the FC trial (P < 0.05). Conclusions Neither brain 5-HT nor DA systems would appear to be implicated in the fatigue process when exercise is performed without significant thermoregulatory stress, thus indicating fatigue development during exercise in relatively cold temperatures to occur predominantly due to glycogen depletion. PMID:20507554

  20. Distributed performance counters

    SciTech Connect

    Davis, Kristan D; Evans, Kahn C; Gara, Alan; Satterfield, David L

    2013-11-26

    A plurality of first performance counter modules is coupled to a plurality of processing cores. The plurality of first performance counter modules is operable to collect performance data associated with the plurality of processing cores respectively. A plurality of second performance counter modules are coupled to a plurality of L2 cache units, and the plurality of second performance counter modules are operable to collect performance data associated with the plurality of L2 cache units respectively. A central performance counter module may be operable to coordinate counter data from the plurality of first performance counter modules and the plurality of second performance modules, the a central performance counter module, the plurality of first performance counter modules, and the plurality of second performance counter modules connected by a daisy chain connection.

  1. NREL module energy rating methodology

    SciTech Connect

    Whitaker, C.; Newmiller, J.; Kroposki, B.

    1995-11-01

    The goals of this project were to develop a tool for: evaluating one module in different climates; comparing different modules; provide a Q&D method for estimating periodic energy production; provide an achievable module rating; provide an incentive for manufacturers to optimize modules to non-STC conditions; and to have a consensus-based, NREL-sponsored activity. The approach taken was to simulate module energy for five reference days of various weather conditions. A performance model was developed.

  2. Loadable Hypervisor Modules

    SciTech Connect

    Naughton, III, Thomas J; Vallee, Geoffroy R; Scott, Stephen L; Aderholdt, Ferrol

    2010-01-01

    This paper discusses the implementation of a new hypervisor mechanism for loading dynamic shared objects (modules) at runtime. These loadable hypervisor modules (LHM) are modeled after the loadable kernel modules used in Linux. We detail the current LHM implementation based on the Xen hypervisor. Potential use cases for this LHM mechanism include dynamic hypervisor instrumentation for debug tracing or performance analysis. We discuss the initial LHM prototype and future plans.

  3. Auditory Feedback Differentially Modulates Behavioral and Neural Markers of Objective and Subjective Performance When Tapping to Your Heartbeat

    PubMed Central

    Canales-Johnson, Andrés; Silva, Carolina; Huepe, David; Rivera-Rei, Álvaro; Noreika, Valdas; Garcia, María del Carmen; Silva, Walter; Ciraolo, Carlos; Vaucheret, Esteban; Sedeño, Lucas; Couto, Blas; Kargieman, Lucila; Baglivo, Fabricio; Sigman, Mariano; Chennu, Srivas; Ibáñez, Agustín; Rodríguez, Eugenio; Bekinschtein, Tristan A.

    2015-01-01

    Interoception, the perception of our body internal signals, plays a key role in maintaining homeostasis and guiding our behavior. Sometimes, we become aware of our body signals and use them in planning and strategic thinking. Here, we show behavioral and neural dissociations between learning to follow one's own heartbeat and metacognitive awareness of one's performance, in a heartbeat-tapping task performed before and after auditory feedback. The electroencephalography amplitude of the heartbeat-evoked potential in interoceptive learners, that is, participants whose accuracy of tapping to their heartbeat improved after auditory feedback, was higher compared with non-learners. However, an increase in gamma phase synchrony (30–45 Hz) after the heartbeat auditory feedback was present only in those participants showing agreement between objective interoceptive performance and metacognitive awareness. Source localization in a group of participants and direct cortical recordings in a single patient identified a network hub for interoceptive learning in the insular cortex. In summary, interoceptive learning may be mediated by the right insular response to the heartbeat, whereas metacognitive awareness of learning may be mediated by widespread cortical synchronization patterns. PMID:25899708

  4. Pre-stimulus functional networks modulate task performance in time-pressured evidence gathering and decision-making

    PubMed Central

    Sherwin, Jason Samuel; Muraskin, Jordan; Sajda, Paul

    2015-01-01

    Rapid perceptual decision-making is believed to depend upon efficient allocation of neural resources to the processing of transient stimuli within task-relevant contexts. Given decision-making under severe time pressure, it is reasonable to posit that the brain configures itself, prior to processing stimulus information, in a way that depends upon prior beliefs and/or anticipation. However, relatively little is known about such configuration processes, how they might be manifested in the human brain, or ultimately how they mediate task performance. Here we show that network configuration, defined via pre-stimulus functional connectivity measures estimated from functional magnetic resonance imaging (fMRI) data, is predictive of performance in a time-pressured Go/No-Go task. Specifically, using connectivity measures to summarize network properties, we show that pre-stimulus brain state can be used to discriminate behaviorally correct and incorrect trials, as well as behaviorally correct commission and omission trial categories. More broadly, our results show that pre-stimulus functional configurations of cortical and sub-cortical networks can be a major determiner of task performance. PMID:25614974

  5. What should DOE do to help establish voluntary consensus standards for measuring and rating the performance of PV modules?

    NASA Technical Reports Server (NTRS)

    Runkle, L. D.

    1984-01-01

    In response to concern expressed by the photovoltaics community over progress toward the establishment and issuance of concensus standards on photovoltaic performance measurements, a review of the status of and progress in developing these standards was conducted. It examined the roles of manufacturers, and consumers and the national laboratories funded by the U.S. Department of Energy (DOE) in supporting this effort. This was done by means of a series of discussions with knowledgeable members of the photovoltaic community. Results of these interviews are summarized and a new approach to managing support of standards activity is recommended that responds to specific problems found in the performance measurement standards area. The study concludes that there is a positive role to be played by the U.S. Department of Energy in establishing collector performance measurement standards. It recommends that DOE continue to provide direct financial support for selected committees and for research at national laboratories, and that management of the activity be restructured to increase the authority and responsibility of the consensus committees.

  6. Pre-stimulus functional networks modulate task performance in time-pressured evidence gathering and decision-making.

    PubMed

    Sherwin, Jason Samuel; Muraskin, Jordan; Sajda, Paul

    2015-05-01

    Rapid perceptual decision-making is believed to depend upon efficient allocation of neural resources to the processing of transient stimuli within task-relevant contexts. Given decision-making under severe time pressure, it is reasonable to posit that the brain configures itself, prior to processing stimulus information, in a way that depends upon prior beliefs and/or anticipation. However, relatively little is known about such configuration processes, how they might be manifested in the human brain, or ultimately how they mediate task performance. Here we show that network configuration, defined via pre-stimulus functional connectivity measures estimated from functional magnetic resonance imaging (fMRI) data, is predictive of performance in a time-pressured Go/No-Go task. Specifically, using connectivity measures to summarize network properties, we show that pre-stimulus brain state can be used to discriminate behaviorally correct and incorrect trials, as well as behaviorally correct commission and omission trial categories. More broadly, our results show that pre-stimulus functional configurations of cortical and sub-cortical networks can be a major determiner of task performance.

  7. Auditory Feedback Differentially Modulates Behavioral and Neural Markers of Objective and Subjective Performance When Tapping to Your Heartbeat.

    PubMed

    Canales-Johnson, Andrés; Silva, Carolina; Huepe, David; Rivera-Rei, Álvaro; Noreika, Valdas; Garcia, María del Carmen; Silva, Walter; Ciraolo, Carlos; Vaucheret, Esteban; Sedeño, Lucas; Couto, Blas; Kargieman, Lucila; Baglivo, Fabricio; Sigman, Mariano; Chennu, Srivas; Ibáñez, Agustín; Rodríguez, Eugenio; Bekinschtein, Tristan A

    2015-11-01

    Interoception, the perception of our body internal signals, plays a key role in maintaining homeostasis and guiding our behavior. Sometimes, we become aware of our body signals and use them in planning and strategic thinking. Here, we show behavioral and neural dissociations between learning to follow one's own heartbeat and metacognitive awareness of one's performance, in a heartbeat-tapping task performed before and after auditory feedback. The electroencephalography amplitude of the heartbeat-evoked potential in interoceptive learners, that is, participants whose accuracy of tapping to their heartbeat improved after auditory feedback, was higher compared with non-learners. However, an increase in gamma phase synchrony (30-45 Hz) after the heartbeat auditory feedback was present only in those participants showing agreement between objective interoceptive performance and metacognitive awareness. Source localization in a group of participants and direct cortical recordings in a single patient identified a network hub for interoceptive learning in the insular cortex. In summary, interoceptive learning may be mediated by the right insular response to the heartbeat, whereas metacognitive awareness of learning may be mediated by widespread cortical synchronization patterns. PMID:25899708

  8. Effects of annealing on performances of 1.3-μm InAs-InGaAs-GaAs quantum dot electroabsorption modulators.

    PubMed

    Lee, Shuh Ying; Yoon, Soon Fatt; Ngo, Andrew Cy; Guo, Tina

    2013-01-01

    In this work, we investigated the effects of quantum dot (QD) annealing (as-grown, 600°C-annealed, and 750°C-annealed) on the preliminary performances of 1.3-μm InAs-InGaAs-GaAs quantum dot electroabsorption modulators (QD-EAMs). Both extinction ratio and insertion loss were found to vary inversely with the annealing temperature. Most importantly, the 3-dB response of the 750°C-annealed lumped-element QD-EAM was found to be 1.6 GHz at zero reverse bias voltage - the lowest reverse bias voltage reported. We believe that this work will be beneficial to researchers working on on-chip integration of QD-EAMs with other devices since energy consumption will be an important consideration.

  9. Performance of free-space optical communication system using differential phase-shift keying subcarrier-intensity modulated over the exponentiated Weibull channel

    NASA Astrophysics Data System (ADS)

    Gao, Zhengguang; Liu, Hongzhan; Liao, Renbo; Ma, Xiaoping

    2015-10-01

    A differential phase-shift keying modulation for free-space optical (FSO) communication is considered in atmospheric turbulence modeled by the exponentiated Weibull distribution. The selection combining (SelC) spatial diversity is used to mitigate the effects of atmospheric turbulence. We analyze the average bit error rate (BER) of the system using SelC spatial diversity by Gauss-Laguerre approximation. The effect of aperture averaging and spatial diversity on the outage probability is also studied. The numerical results show that it requires a smaller level of signal-to-noise ratio to reach the same BER when large aperture and SelC spatial diversity are deployed in the FSO system. Moreover, it is proved that aperture averaging and SelC spatial diversity are effective for improving the performance of the system's outage probability.

  10. Improved performance of HgCdTe infrared detector focal plane arrays by modulating light field based on photonic crystal structure

    SciTech Connect

    Liang, Jian; Hu, Weida Ye, Zhenhua; Li, Zhifeng; Chen, Xiaoshuang Lu, Wei; Liao, Lei

    2014-05-14

    An HgCdTe long-wavelength infrared focal plane array photodetector is proposed by modulating light distributions based on the photonic crystal. It is shown that a promising prospect of improving performance is better light harvest and dark current limitation. To optimize the photon field distributions of the HgCdTe-based photonic crystal structure, a numerical method is built by combining the finite-element modeling and the finite-difference time-domain simulation. The optical and electrical characteristics of designed HgCdTe mid-wavelength and long-wavelength photon-trapping infrared detector focal plane arrays are obtained numerically. The results indicate that the photon crystal structure, which is entirely compatible with the large infrared focal plane arrays, can significantly reduce the dark current without degrading the quantum efficiency compared to the regular mesa or planar structure.

  11. Modulating Memory Performance in Healthy Subjects with Transcranial Direct Current Stimulation Over the Right Dorsolateral Prefrontal Cortex

    PubMed Central

    Smirni, Daniela; Turriziani, Patrizia; Mangano, Giuseppa Renata; Cipolotti, Lisa; Oliveri, Massimiliano

    2015-01-01

    Objective The role of the Dorsolateral Prefrontal Cortex (DLPFC) in recognition memory has been well documented in lesion, neuroimaging and repetitive Transcranial Magnetic Stimulation (rTMS) studies. The aim of the present study was to investigate the effects of transcranial Direct Current Stimulation (tDCS) over the left and the right DLPFC during the delay interval of a non-verbal recognition memory task. Method 36 right-handed young healthy subjects participated in the study. The experimental task was an Italian version of Recognition Memory Test for unknown faces. Study included two experiments: in a first experiment, each subject underwent one session of sham tDCS and one session of left or right cathodal tDCS; in a second experiment each subject underwent one session of sham tDCS and one session of left or right anodal tDCS. Results Cathodal tDCS over the right DLPFC significantly improved non verbal recognition memory performance, while cathodal tDCS over the left DLPFC had no effect. Anodal tDCS of both the left and right DLPFC did not modify non verbal recognition memory performance. Conclusion Complementing the majority of previous studies, reporting long term memory facilitations following left prefrontal anodal tDCS, the present findings show that cathodal tDCS of the right DLPFC can also improve recognition memory in healthy subjects. PMID:26679936

  12. Transistors for Electric Motor Drives: High-Performance GaN HEMT Modules for Agile Power Electronics

    SciTech Connect

    2010-09-01

    ADEPT Project: Transphorm is developing transistors with gallium nitride (GaN) semiconductors that could be used to make cost-effective, high-performance power converters for a variety of applications, including electric motor drives which transmit power to a motor. A transistor acts like a switch, controlling the electrical energy that flows around an electrical circuit. Most transistors today use low-cost silicon semiconductors to conduct electrical energy, but silicon transistors don’t operate efficiently at high speeds and voltage levels. Transphorm is using GaN as a semiconductor material in its transistors because GaN performs better at higher voltages and frequencies, and it is more energy efficient than straight silicon. However, Transphorm is using inexpensive silicon as a base to help keep costs low. The company is also packaging its transistors with other electrical components that can operate quickly and efficiently at high power levels—increasing the overall efficiency of both the transistor and the entire motor drive.

  13. Religion and action control: Faith-specific modulation of the Simon effect but not Stop-Signal performance.

    PubMed

    Hommel, Bernhard; Colzato, Lorenza S; Scorolli, Claudia; Borghi, Anna M; van den Wildenberg, Wery P M

    2011-08-01

    Previous findings suggest that religion has a specific impact on attentional processes. Here we show that religion also affects action control. Experiment 1 compared Dutch Calvinists and Dutch atheists, matched for age, sex, intelligence, education, and cultural and socio-economic background, and Experiment 2 compared Italian Catholics with matched Italian seculars. As expected, Calvinists showed a smaller and Catholics a larger Simon effect than nonbelievers, while performance of the groups was comparable in the Stop-Signal task. This pattern suggests that religions emphasizing individualism or collectivism affects action control in specific ways, presumably by inducing chronic biases towards a more "exclusive" or "inclusive" style of decision-making. Interestingly, there was no evidence that religious practice affects inhibitory skills.

  14. Circadian Adaptation to Night Shift Work Influences Sleep, Performance, Mood and the Autonomic Modulation of the Heart

    PubMed Central

    Boudreau, Philippe; Dumont, Guy A.; Boivin, Diane B.

    2013-01-01

    Our aim was to investigate how circadian adaptation to night shift work affects psychomotor performance, sleep, subjective alertness and mood, melatonin levels, and heart rate variability (HRV). Fifteen healthy police officers on patrol working rotating shifts participated to a bright light intervention study with 2 participants studied under two conditions. The participants entered the laboratory for 48 h before and after a series of 7 consecutive night shifts in the field. The nighttime and daytime sleep periods were scheduled during the first and second laboratory visit, respectively. The subjects were considered “adapted” to night shifts if their peak salivary melatonin occurred during their daytime sleep period during the second visit. The sleep duration and quality were comparable between laboratory visits in the adapted group, whereas they were reduced during visit 2 in the non-adapted group. Reaction speed was higher at the end of the waking period during the second laboratory visit in the adapted compared to the non-adapted group. Sleep onset latency (SOL) and subjective mood levels were significantly reduced and the LF∶HF ratio during daytime sleep was significantly increased in the non-adapted group compared to the adapted group. Circadian adaptation to night shift work led to better performance, alertness and mood levels, longer daytime sleep, and lower sympathetic dominance during daytime sleep. These results suggest that the degree of circadian adaptation to night shift work is associated to different health indices. Longitudinal studies are required to investigate long-term clinical implications of circadian misalignment to atypical work schedules. PMID:23923024

  15. FASTBUS Snoop Diagnostic Module

    SciTech Connect

    Walz, H.V.; Downing, R.

    1980-11-01

    Development of the FASTBUS Snoop Module, undertaken as part of the prototype program for the new interlaboratory data bus standard, is described. The Snoop Module resides on a FASTBUS crate segment and provides diagnostic monitoring and testing capability. Communication with a remote host computer is handled independent of FASTBUS through a serial link. The module consists of a high-speed ECL front-end to monitor and single-step FASTBUS cycles, a master-slave interface, and a control microprocessor with serial communication ports. Design details and performance specifications of the prototype module are reported. 9 figures, 1 table.

  16. Light-Modulated Responses of Growth and Photosynthetic Performance to Ocean Acidification in the Model Diatom Phaeodactylum tricornutum

    PubMed Central

    Li, Yahe; Xu, Juntian; Gao, Kunshan

    2014-01-01

    Ocean acidification (OA) due to atmospheric CO2 rise is expected to influence marine primary productivity. In order to investigate the interactive effects of OA and light changes on diatoms, we grew Phaeodactylum tricornutum, under ambient (390 ppmv; LC) and elevated CO2 (1000 ppmv; HC) conditions for 80 generations, and measured its physiological performance under different light levels (60 µmol m−2 s−1, LL; 200 µmol m−2 s−1, ML; 460 µmol m−2 s−1, HL) for another 25 generations. The specific growth rate of the HC-grown cells was higher (about 12–18%) than that of the LC-grown ones, with the highest under the ML level. With increasing light levels, the effective photochemical yield of PSII (Fv′/Fm′) decreased, but was enhanced by the elevated CO2, especially under the HL level. The cells acclimated to the HC condition showed a higher recovery rate of their photochemical yield of PSII compared to the LC-grown cells. For the HC-grown cells, dissolved inorganic carbon or CO2 levels for half saturation of photosynthesis (K1/2 DIC or K1/2 CO2) increased by 11, 55 and 32%, under the LL, ML and HL levels, reflecting a light dependent down-regulation of carbon concentrating mechanisms (CCMs). The linkage between higher level of the CCMs down-regulation and higher growth rate at ML under OA supports the theory that the saved energy from CCMs down-regulation adds on to enhance the growth of the diatom. PMID:24828454

  17. Visual search performance is predicted by the degree to which selective attention to features modulates the ERP between 350 and 600ms.

    PubMed

    Milne, Elizabeth; Dunn, Stephanie A; Freeth, Megan; Rosas-Martinez, Luisa

    2013-05-01

    Efficient visual search necessitates perception of items in the visual array, rapid classification of items as either targets or distractors, and the selection of target items. Individuals vary in the speed with which they perform these operations and can detect targets within cluttered arrays, as shown in visual search tasks. Individuals with autism spectrum disorders (ASD) show particular strengths in visual search. The aim of the current study was to develop an understanding the origin of individual variability in visual search by delineating the processes involved in feature-based target detection, and establishing which, if any, of these processes predict search efficiency. EEG was recorded while participants performed a feature-based selective attention task from which the following EEG variables were computed: P1 amplitude; P1 latency; selection negativity; induced γ-band power and P3b amplitude. These variables are considered to reflect stimulus encoding, feedback amplification of attended features, cognitive utilization and resource allocation during event classification respectively. Participants also completed a separate visual search task. Regression analyses revealed that only the ERP component associated with resource allocation during event classification (P3b) significantly predicted search efficiency. These data suggest that individual variability in visual search is related to a reduction in modulation of attention allocation to visual features. Implications for the understanding of superior visual search in individuals with ASD are discussed.

  18. Design and expected performances of the SCAO-WFS module of SIMPLE, the high-resolution near-infrared spectrometer for E-ELT

    NASA Astrophysics Data System (ADS)

    Tozzi, A.; Oliva, E.; Le Louarn, M.; Origlia, L.

    2010-07-01

    We present and discuss the design and expected performances of the SCAO-WFS module of SIMPLE, the highsd resolution near-infrared spectrometer for the E-ELT which is designed to operate in the wavelengths range 0.84-2.5μm with an entrance slit width of 27mas which yields a spectral resolving power of R=130,000. We analyze both pyramid and SH wave-front sensors operating at near-infrared wavelengths (1-2 μm). The main results can be summarized as follows. - Good levels of AO correction can only be achieved within a few arc-sec of the reference star. The primary applications of SCAO correction are therefore observations where the science object is compact and bright enough to be used as reference star, feeding the WFS via a beam-splitter. We concentrate on a WFS operating at nearinfrared wavelengths because many of the scientific targets of SIMPLE are intrinsically very red. - The pyramid WFS provides better performances than the SH, because it is less affected by aliasing errors. - The quality of AO correction is almost independent on the wavelength at which the wave-front is sensed. Therefore, we simplify the design the WFS module by not including the K-band, i.e. operating in the 1.0-2.1μm range. Extension to shorter wavelengths is also possible but requires exchanging the atmospheric dispersion compensator. - Using a pyramid WFS with 84x84 sub-apertures one can achieve remarkably high values of light-concentration in the slit, i.e. ~70% in K and ~40% at 0.9μm. - The limiting magnitude for the 84×84 WFS is about 13.5+2.5•log(η), where η is the fraction of stellar light sent to the WFS by the beam-splitter. - Somewhat fainter limits, i.e. magnitudes ~14.0+2.5•log(η), can be achieved by changing the camera optics of the WFS and sampling 42×42 sub-apertures.

  19. Performance of a Knowledge-Based Model for Optimization of Volumetric Modulated Arc Therapy Plans for Single and Bilateral Breast Irradiation

    PubMed Central

    Fogliata, Antonella; Nicolini, Giorgia; Bourgier, Celine; Clivio, Alessandro; De Rose, Fiorenza; Fenoglietto, Pascal; Lobefalo, Francesca; Mancosu, Pietro; Tomatis, Stefano; Vanetti, Eugenio; Scorsetti, Marta; Cozzi, Luca

    2015-01-01

    Purpose To evaluate the performance of a model-based optimisation process for volumetric modulated arc therapy, VMAT, applied to whole breast irradiation. Methods and Materials A set of 150 VMAT dose plans with simultaneous integrated boost were selected to train a model for the prediction of dose-volume constraints. The dosimetric validation was done on different groups of patients from three institutes for single (50 cases) and bilateral breast (20 cases). Results Quantitative improvements were observed between the model-based and the reference plans, particularly for heart dose. Of 460 analysed dose-volume objectives, 13% of the clinical plans failed to meet the constraints while the respective model-based plans succeeded. Only in 5 cases did the reference plans pass while the respective model-based failed the criteria. For the bilateral breast analysis, the model-based plans resulted in superior or equivalent dose distributions to the reference plans in 96% of the cases. Conclusions Plans optimised using a knowledge-based model to determine the dose-volume constraints showed dosimetric improvements when compared to earlier approved clinical plans. The model was applicable to patients from different centres for both single and bilateral breast irradiation. The data suggests that the dose-volume constraint optimisation can be effectively automated with the new engine and could encourage its application to clinical practice. PMID:26691687

  20. How does reading performance modulate the impact of orthographic knowledge on speech processing? A comparison of normal readers and dyslexic adults.

    PubMed

    Pattamadilok, Chotiga; Nelis, Aubéline; Kolinsky, Régine

    2014-04-01

    Studies on proficient readers showed that speech processing is affected by knowledge of the orthographic code. Yet, the automaticity of the orthographic influence depends on task demand. Here, we addressed this automaticity issue in normal and dyslexic adult readers by comparing the orthographic effects obtained in two speech processing tasks that are or not sensitive to strategies developed by participants. Our finding showed that while participants' performance in a metaphonological task, which is known to be strategy prone, was affected by their orthographic knowledge regardless of the childhood diagnosis of dyslexia or of their actual reading-related skills, this latter factor significantly modulated the orthographic influence found in a more natural speech recognition task. The finding supports the claim that while any individuals who know a reading code are able to resort to their orthographic knowledge when they process speech, a more profound modification of the speech processing system by the orthographic code takes place only in readers who have reached a certain level of reading expertise.

  1. Module Configuration

    DOEpatents

    Oweis, Salah; D'Ussel, Louis; Chagnon, Guy; Zuhowski, Michael; Sack, Tim; Laucournet, Gaullume; Jackson, Edward J.

    2002-06-04

    A stand alone battery module including: (a) a mechanical configuration; (b) a thermal management configuration; (c) an electrical connection configuration; and (d) an electronics configuration. Such a module is fully interchangeable in a battery pack assembly, mechanically, from the thermal management point of view, and electrically. With the same hardware, the module can accommodate different cell sizes and, therefore, can easily have different capacities. The module structure is designed to accommodate the electronics monitoring, protection, and printed wiring assembly boards (PWAs), as well as to allow airflow through the module. A plurality of modules may easily be connected together to form a battery pack. The parts of the module are designed to facilitate their manufacture and assembly.

  2. MoNetFamily: a web server to infer homologous modules and module-module interaction networks in vertebrates.

    PubMed

    Lin, Chun-Yu; Lin, Yi-Wei; Yu, Shang-Wen; Lo, Yu-Shu; Yang, Jinn-Moon

    2012-07-01

    A module is a fundamental unit forming with highly connected proteins and performs a certain kind of biological functions. Modules and module-module interaction (MMI) network are essential for understanding cellular processes and functions. The MoNetFamily web server can identify the modules, homologous modules (called module family) and MMI networks across multiple species for the query protein(s). This server first finds module candidates of the query by using BLASTP to search the module template database (1785 experimental and 1252 structural templates). MoNetFamily then infers the homologous modules of the selected module candidate using protein-protein interaction (PPI) families. According to homologous modules and PPIs, we statistically calculated MMIs and MMI networks across multiple species. For each module candidate, MoNetFamily identifies its neighboring modules and their MMIs in module networks of Homo sapiens, Mus musculus and Danio rerio. Finally, MoNetFamily shows the conserved proteins, PPI profiles and functional annotations of the module family. Our results indicate that the server can be useful for MMI network (e.g. 1818 modules and 9678 MMIs in H. sapiens) visualizations and query annotations using module families and neighboring modules. We believe that the server is able to provide valuable insights to determine homologous modules and MMI networks across multiple species for studying module evolution and cellular processes. The MoNetFamily sever is available at http://monetfamily.life.nctu.edu.tw.

  3. Individual differences in action co-representation: not personal distress or subclinical psychotic experiences but sex composition modulates joint action performance.

    PubMed

    van der Weiden, Anouk; Aarts, Henk; Prikken, Merel; van Haren, Neeltje E M

    2016-02-01

    Successful social interaction requires the ability to integrate as well as distinguish own and others' actions. Normally, the integration and distinction of self and other are a well-balanced process, occurring without much effort or conscious attention. However, not everyone is blessed with the ability to balance self-other distinction and integration, resulting in personal distress in reaction to other people's emotions or even a loss of self [e.g., in (subclinical) psychosis]. Previous research has demonstrated that the integration and distinction of others' actions cause interference with one's own action performance (commonly assessed with a social Simon task). The present study had two goals. First, as previous studies on the social Simon effect employed relatively small samples (N < 50 per test), we aimed for a sample size that allowed us to test the robustness of the action interference effect. Second, we tested to what extent action interference reflects individual differences in traits related to self-other distinction (i.e., personal distress in reaction to other people's emotions and subclinical psychotic symptoms). Based on a questionnaire study among a large sample (N = 745), we selected a subsample (N = 130) of participants scoring low, average, or high on subclinical psychotic symptoms, or on personal distress. The selected participants performed a social Simon task. Results showed a robust social Simon effect, regardless of individual differences in personal distress or subclinical psychotic symptoms. However, exploratory analyses revealed that the sex composition of interaction pairs modulated social Simon effects. Possible explanations for these findings are discussed. PMID:26525711

  4. Performance evaluation of reflective electro-absorption modulator based optical source using a broadband light seed source for colorless WDM-PON applications.

    PubMed

    Kim, Chul Han

    2013-05-20

    The performance of reflective electro-absorption modulator (R-EAM) based optical source has been evaluated for the use in high-capacity wavelength-division multiplexed passive optical networks (WDM-PONs). In our measurements, a broadband light source (BLS) was used as a seeding source for the cost-effective implementation of R-EAM based optical source. At first, a bit-error rate (BER) floor at 10(-6) was observed even in a back-to-back configuration with the BLS seeded R-EAM source. This is mainly because of the excess intensity noise (EIN) within BLS and the signal-to-noise ratio (SNR) degradation induced by a high insertion loss of R-EAM. To mitigate both effects of EIN and SNR degradation, a reflective semiconductor optical amplifier (RSOA) was also used for the implementation of our BLS seeded R-EAM source. Then, we have evaluated the impact of various noises, such as EIN, chromatic dispersion of transmission fiber and in-band crosstalk, on the system's performance using our BLS seeded R-EAM optical source. From the results, we have found that a 3-dB bandwidth of the BLS seeded R-EAM optical source should be wider than ~0.8 nm to achieve an error-free transmission of 1.25 Gb/s signal. We have also confirmed that there was a trade-off between the dispersion- and the in-band crosstalk-induced penalties due to the wide source bandwidth of our BLS seeded R-EAM source, like the cases of BLS seeded RSOA and Fabry-Perot laser diode (FP-LD) sources. PMID:23736511

  5. High Performance Composites. "Designed" Materials for the New Millennium. 2nd Module in a Series on Advanced Materials. Resources in Technology.

    ERIC Educational Resources Information Center

    Jacobs, James A.

    1994-01-01

    This learning module on composites such as polymer matrix, metal matrix, ceramic matrix, particulate, and laminar includes a design brief giving context, objectives, evaluation, student outcomes, and quiz. (SK)

  6. Continuous-Time ΣΔ ADC with Implicit Variable Gain Amplifier for CMOS Image Sensor

    PubMed Central

    Bermak, Amine; Abbes, Amira; Amor Benammar, Mohieddine

    2014-01-01

    This paper presents a column-parallel continuous-time sigma delta (CTSD) ADC for mega-pixel resolution CMOS image sensor (CIS). The sigma delta modulator is implemented with a 2nd order resistor/capacitor-based loop filter. The first integrator uses a conventional operational transconductance amplifier (OTA), for the concern of a high power noise rejection. The second integrator is realized with a single-ended inverter-based amplifier, instead of a standard OTA. As a result, the power consumption is reduced, without sacrificing the noise performance. Moreover, the variable gain amplifier in the traditional column-parallel read-out circuit is merged into the front-end of the CTSD modulator. By programming the input resistance, the amplitude range of the input current can be tuned with 8 scales, which is equivalent to a traditional 2-bit preamplification function without consuming extra power and chip area. The test chip prototype is fabricated using 0.18 μm CMOS process and the measurement result shows an ADC power consumption lower than 63.5 μW under 1.4 V power supply and 50 MHz clock frequency. PMID:24772012

  7. Continuous-time ΣΔ ADC with implicit variable gain amplifier for CMOS image sensor.

    PubMed

    Tang, Fang; Bermak, Amine; Abbes, Amira; Benammar, Mohieddine Amor

    2014-01-01

    This paper presents a column-parallel continuous-time sigma delta (CTSD) ADC for mega-pixel resolution CMOS image sensor (CIS). The sigma delta modulator is implemented with a 2nd order resistor/capacitor-based loop filter. The first integrator uses a conventional operational transconductance amplifier (OTA), for the concern of a high power noise rejection. The second integrator is realized with a single-ended inverter-based amplifier, instead of a standard OTA. As a result, the power consumption is reduced, without sacrificing the noise performance. Moreover, the variable gain amplifier in the traditional column-parallel read-out circuit is merged into the front-end of the CTSD modulator. By programming the input resistance, the amplitude range of the input current can be tuned with 8 scales, which is equivalent to a traditional 2-bit preamplification function without consuming extra power and chip area. The test chip prototype is fabricated using 0.18 μm CMOS process and the measurement result shows an ADC power consumption lower than 63.5 μW under 1.4 V power supply and 50 MHz clock frequency. PMID:24772012

  8. Direct spatial antenna modulation

    NASA Astrophysics Data System (ADS)

    Uhl, Brecken H.

    This body of work seeks to define Direct Spatial Antenna Modulation (DSAM) as a new and unique approach to data symbol modulation and phased array control by comparing and contrasting the technique to conventional approaches. A rigorous development of the theoretical and practical implications of the DSAM technique as a general approach are presented. The theoretical development of several DSAM examples are included. Implementation and measurement results for several prototypes based on DSAM principles are analyzed. The work concludes with a summary of the impact of the present DSAM developments and a proposal for additional investigation. Results are included that show equivalent measured bit error rate performance for DSAM as compared to conventional modulation for both two-state and four-state phase modulation. Measured beam control accuracy of a DSAM phased array is included, along with several other example DSAM phased array analyses. Supported by an analysis linking a DSAM technique with complete complex-plane modulation control, the DSAM concept is applied to a commercial antenna and an experiment demonstrates wideband phase control. Analytical and simulation results demonstrate joint beamforming and modulation in a DSAM array. Several implications of the results of the investigation are important to consider: 1. The DSAM approach represents a new way to treat the conventional relationship between modulation and antennas, and has been demonstrated through a significant number and variety of analyses, simulations, and experiments. 2. The DSAM approach takes direct advantage of inherent antenna radiating properties to perform conventionally non-antenna functions; the approach is in this way both enabled and limited. 3. The DSAM approach has been shown in several examples to offer beneficial engineering performance trade-offs with respect to architecture options, as well as important performance parameters such as power consumption, breadth of frequency

  9. Improvements in and actual performance of the Plant Experiment Unit onboard Kibo, the Japanese experiment module on the international space station

    NASA Astrophysics Data System (ADS)

    Yano, Sachiko; Kasahara, Haruo; Masuda, Daisuke; Tanigaki, Fumiaki; Shimazu, Toru; Suzuki, Hiromi; Karahara, Ichirou; Soga, Kouichi; Hoson, Takayuki; Tayama, Ichiro; Tsuchiya, Yoshikazu; Kamisaka, Seiichiro

    2013-03-01

    In 2004, Japan Aerospace Exploration Agency developed the engineered model of the Plant Experiment Unit and the Cell Biology Experiment Facility. The Plant Experiment Unit was designed to be installed in the Cell Biology Experiment Facility and to support the seed-to-seed life cycle experiment of Arabidopsis plants in space in the project named Space Seed. Ground-based experiments to test the Plant Experiment Unit showed that the unit needed further improvement of a system to control the water content of a seedbed using an infrared moisture analyzer and that it was difficult to keep the relative humidity inside the Plant Experiment Unit between 70 and 80% because the Cell Biology Experiment Facility had neither a ventilation system nor a dehumidifying system. Therefore, excess moisture inside the Cell Biology Experiment Facility was removed with desiccant bags containing calcium chloride. Eight flight models of the Plant Experiment Unit in which dry Arabidopsis seeds were fixed to the seedbed with gum arabic were launched to the International Space Station in the space shuttle STS-128 (17A) on August 28, 2009. Plant Experiment Unit were installed in the Cell Biology Experiment Facility with desiccant boxes, and then the Space Seed experiment was started in the Japanese Experiment Module, named Kibo, which was part of the International Space Station, on September 10, 2009 by watering the seedbed and terminated 2 months later on November 11, 2009. On April 19, 2010, the Arabidopsis plants harvested in Kibo were retrieved and brought back to Earth by the space shuttle mission STS-131 (19A). The present paper describes the Space Seed experiment with particular reference to the development of the Plant Experiment Unit and its actual performance in Kibo onboard the International Space Station. Downlinked images from Kibo showed that the seeds had started germinating 3 days after the initial watering. The plants continued growing, producing rosette leaves, inflorescence

  10. Amplitude Modulator Chassis

    SciTech Connect

    Erbert, G

    2009-09-01

    The Amplitude Modulator Chassis (AMC) is the final component in the MOR system and connects directly to the PAM input through a 100-meter fiber. The 48 AMCs temporally shape the 48 outputs of the MOR using an arbitrary waveform generator coupled to an amplitude modulator. The amplitude modulation element is a two stage, Lithium Niobate waveguide device, where the intensity of the light passing through the device is a function of the electrical drive applied. The first stage of the modulator is connected to a programmable high performance Arbitrary Waveform Generator (AWG) consisting of 140 impulse generators space 250 ps apart. An arbitrary waveform is generated by independently varying the amplitude of each impulse generator and then summing the impulses together. In addition to the AWG a short pulse generator is also connected to the first stage of the modulator to provide a sub 100-ps pulse used for timing experiments. The second stage of the modulator is connect to a square pulse generator used to further attenuate any pre or post pulse light passing through the first stage of the modulator. The fast rise and fall time of the square pulse generator is also used to produce fast rise and fall times of the AWG by clipping the AWG pulse. For maximum extinction, a pulse bias voltage is applied to each stage of the modulator. A pulse voltage is applied as opposed to a DC voltage to prevent charge buildup on the modulator. Each bias voltage is adjustable to provide a minimum of 50-dB extinction. The AMC is controlled through ICCS to generate the desired temporal pulse shape. This process involves a closed-loop control algorithm, which compares the desired temporal waveform to the produced optical pulse, and iterates the programming of the AWG until the two waveforms agree within an allowable tolerance.

  11. Complex Burn Region Module (CBRM) update

    NASA Technical Reports Server (NTRS)

    Adams, Carl L.; Jenkins, Billy

    1991-01-01

    Presented here is a Complex Burn Region Module (CBRM) update for the Solid Rocket Internal Ballistics Module (SRIBM) Program for the Advanced Solid Rocket Motor (ASRM) design/performance assessments. The goal was to develop an improved version of the solid rocket internal ballistics module program that contains a diversified complex region model for motor grain design, performance prediction, and evaluation.

  12. A Comparison of Course Completion, Satisfaction, Achievement, and Performance among Non-Profit Professionals Who Complete Andragogical or Pedagogical Online Learning Modules on Grant Writing

    ERIC Educational Resources Information Center

    Bradley, Joe Bernard, Jr.

    2010-01-01

    The purpose of this study was to compare the outcomes among staff members of nonprofit social service agencies who participated in or completed an andragogically-facilitated or a pedagogically-conducted online learning module on foundation grant writing. The efficacy of andragogical methods is unknown and often debated due to scarce empirical…

  13. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation. Functional modules F9--F16 -- Volume 2, Part 2, Revision 4

    SciTech Connect

    West, J.T.; Hoffman, T.J.; Emmett, M.B.; Childs, K.W.; Petrie, L.M.; Landers, N.F.; Bryan, C.B.; Giles, G.E.

    1995-04-01

    SCALE--a modular code system for Standardized Computer Analyses Licensing Evaluation--has been developed by Oak Ridge National Laboratory at the request of the US Nuclear Regulatory Commission. The SCALE system utilizes well-established computer codes and methods within standard analysis sequences that (1) allow an input format designed for the occasional user and/or novice, (2) automate the data processing and coupling between modules, and (3) provide accurate and reliable results. System development has been directed at problem-dependent cross-section processing and analysis of criticality safety, shielding, heat transfer, and depletion/decay problems. Since the initial release of SCALE in 1980, the code system has been heavily used for evaluation of nuclear fuel facility and package designs. This revision documents Version 4.2 of the system. The manual is divided into three volumes: Volume 1--for the control module documentation, Volume 2--for functional module documentation; and Volume 3--for documentation of the data libraries and subroutine libraries. This volume discusses the following functional modules: MORSE-SGC; HEATING 7.2; KENO V.a; JUNEBUG-II; HEATPLOT-S; REGPLOT 6; PLORIGEN; and OCULAR.

  14. Dehydrated citrus pulp alters feedlot performance of crossbred heifers during the receiving period and modulates serum metabolite concentrations before and after an endotoxin challenge.

    PubMed

    Cribbs, J T; Bernhard, B C; Young, T R; Jennings, M A; Burdick Sanchez, N C; Carroll, J A; Callaway, T R; Schmidt, T B; Johnson, B J; Rathmann, R J

    2015-12-01

    SUN in CON cattle ( < 0.01). After the LPS challenge, DCP-fed cattle had reduced glucose, elevated NEFA, and reduced SUN concentrations ( ≤ 0.01). Results indicate that dietary DCP modulated metabolite concentrations in heifers following an endotoxin challenge and affected feedlot performance when incorporated in receiving diets in replacement of corn. Future studies will need to address strategies to increase DMI or explore levels of DCP less than 10% in the diet of newly received heifer calves. PMID:26641189

  15. Dehydrated citrus pulp alters feedlot performance of crossbred heifers during the receiving period and modulates serum metabolite concentrations before and after an endotoxin challenge.

    PubMed

    Cribbs, J T; Bernhard, B C; Young, T R; Jennings, M A; Burdick Sanchez, N C; Carroll, J A; Callaway, T R; Schmidt, T B; Johnson, B J; Rathmann, R J

    2015-12-01

    SUN in CON cattle ( < 0.01). After the LPS challenge, DCP-fed cattle had reduced glucose, elevated NEFA, and reduced SUN concentrations ( ≤ 0.01). Results indicate that dietary DCP modulated metabolite concentrations in heifers following an endotoxin challenge and affected feedlot performance when incorporated in receiving diets in replacement of corn. Future studies will need to address strategies to increase DMI or explore levels of DCP less than 10% in the diet of newly received heifer calves.

  16. Second generation SLAC modulator

    SciTech Connect

    Donaldson, A.R.; Cron, J.C.; Hanselman, R.R.

    1986-06-01

    The Stanford Linear Accelerator Laboratory has undertaken the construction of a single pass electron-positron collider. In order to reach required beam energy 235 new klystrons needed upgraded modulator systems. The collider will use 50 GeV electrons and positrons. The increase in accelerator energy from the present 30 GeV necessitates the replacement of existing 35 MW klystrons with new 67 MW units. The doubling of klystron output power required a redesign of the modulator system. The 67 MW klystron needs a 350 kV beam voltage pulse with a 3.7 ..mu..s pulse width. A new pulse transformer was designed to deliver the increased voltage and pulse width. Pulse cable design was evaluated to obtain increased reliability of that critical element. The modulator, with the exception of its power supply, was rebuilt to produce the required power increase while enhancing reliability and improving maintainability. An investigation of present thyratron switch tube performance under the new operating conditions resulted in agitation and some warranted panic but these conditions were mitigated after several successful experiments and some evolutionary narrowing of the klystron pulse width. The discussion will cover the upgraded modulator system specifications and some details of the new pulse transformer tank, pulse cable, modulator, and modulator switch tube.

  17. Power-Generation Performance of a π-Structured Thermoelectric Module Containing Mg2Si and MnSi1.73

    NASA Astrophysics Data System (ADS)

    Nakamura, Tomoyuki; Hatakeyama, Kazuya; Minowa, Masahiro; Mito, Youhiko; Arai, Koya; Iida, Tsutomu; Nishio, Keishi

    2015-10-01

    In recent years, environmental problems, for example global warming and depletion of energy resources, have become serious. Thermoelectric power generation has attracted attention as a means of reducing the effects of such problems. Thermoelectric conversion technology can convert thermal energy directly into electrical energy. Therefore, exhaust heat can be converted into electrical energy. Moreover, it is a clean method of power generation that does not discharge CO2 gas when the electricity is generated. The purpose of this study was to fabricate a thermoelectric (TE) module that can be used at mid-range temperatures of 573-873 K. The component materials selected were Mg2Si as n-type semiconductor and MnSi1.73 as p-type semiconductor. These compounds are non-toxic, environmentally benign, lightweight, and relatively abundant compared with other TE compounds. Ag paste was used to join the components. To prevent diffusion of Ag at the interface of the components and the electrodes, the top and bottom of the components were coated with Ni. The TE module was composed of 12 pairs of elements and Ag seats were used for the electrodes. The dimensions of both p and n-type components were 5.0 mm × 5.0 mm × 6.3 mm. Module size was 36.5 mm × 36.0 mm × 7.0 mm, and alumina was used as substrate. The module was inserted between hot and cold plates, in air, and output power was measured. The open circuit voltage and the maximum output power were 1.6 V and 5.6 W, respectively, at Δ T = 548°C (hot side 587°C; cold side 39°C), and the output power density estimated from these results was 4.4 kW/m2.

  18. SCALE: A modular code system for performing standardized computer analyses for licensing evaluation. Functional modules F1--F8 -- Volume 2, Part 1, Revision 4

    SciTech Connect

    Greene, N.M.; Petrie, L.M.; Westfall, R.M.; Bucholz, J.A.; Hermann, O.W.; Fraley, S.K.

    1995-04-01

    SCALE--a modular code system for Standardized Computer Analyses Licensing Evaluation--has been developed by Oak Ridge National Laboratory at the request of the US Nuclear Regulatory Commission. The SCALE system utilizes well-established computer codes and methods within standard analysis sequences that (1) allow an input format designed for the occasional user and/or novice, (2) automate the data processing and coupling between modules, and (3) provide accurate and reliable results. System development has been directed at problem-dependent cross-section processing and analysis of criticality safety, shielding, heat transfer, and depletion/decay problems. Since the initial release of SCALE in 1980, the code system has been heavily used for evaluation of nuclear fuel facility and package designs. This revision documents Version 4.2 of the system. The manual is divided into three volumes: Volume 1--for the control module documentation; Volume 2--for functional module documentation; and Volume 3--for documentation of the data libraries and subroutine libraries.

  19. Firefighting Module

    NASA Astrophysics Data System (ADS)

    1981-01-01

    Aviation Power Supply's mobile firefighting module called Firefly II is mounted on a trailer pulled by a pickup truck. Trailer unit has two three- inch water cannons, and the pickup carries a six inch cannon. Completely self contained, module pumps 3,000 gallons of water a minute from hydrants or open bodies of water. Stream can go as far as 400 feet or can be employed in a high-loft mode to reach the tops of tall refinery towers. Compact Firefly II weighs only 2,500 pounds when fully fueled. Key component is a specially designed two stage pump. Power for the pump is generated by a gas turbine engine. Module also includes an electronic/pump controller, multiple hose connections, up to 1,500 feet of hose and fuel for four hours operation. Firefly trailer can be backed onto specially-built large fireboat.

  20. Firefighting Module

    NASA Astrophysics Data System (ADS)

    1980-01-01

    Aviation Power Supply's mobile firefighting module called Firefly II is mounted on a trailer pulled by a pickup truck. Trailer unit has two three- inch water cannons, and the pickup carries a six inch cannon. Completely self contained, module pumps 3,000 gallons of water a minute from hydrants or open bodies of water. Stream can go as far as 400 feet or can be employed in a high-loft mode to reach the tops of tall refinery towers. Compact Firefly II weighs only 2,500 pounds when fully fueled. Key component is a specially designed two stage pump. Power for the pump is generated by a gas turbine engine. Module also includes an electronic/pump controller, multiple hose connections, up to 1,500 feet of hose and fuel for four hours operation. Firefly trailer can be backed onto specially-built large fireboat.

  1. Thermionic modules

    DOEpatents

    King, Donald B.; Sadwick, Laurence P.; Wernsman, Bernard R.

    2002-06-18

    Modules of assembled microminiature thermionic converters (MTCs) having high energy-conversion efficiencies and variable operating temperatures manufactured using MEMS manufacturing techniques including chemical vapor deposition. The MTCs incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. The MTCs also exhibit maximum efficiencies of just under 30%, and thousands of the devices and modules can be fabricated at modest costs.

  2. Performance of OOK and low-order PPM modulations in optical communications when using APD-based receivers. [Off-On Keying and Pulse Position Modulation using Avalanche PhotoDiodes

    NASA Technical Reports Server (NTRS)

    Abshire, J. B.

    1984-01-01

    The paper computes direct detection laser communications receiver performance when using avalanche photodiode (APD) detectors. The performances are compared in terms of bit error probability vs average signal required per bit when the transmitter uses either on-off keying (OOK) or low-order PPM formats. It is shown that QPPM requires 3 dB less signal than OOK, while BPPM requires the same or slightly more than OOK for the same performance. Optimum APD gain values range from 200 to 400. When using QPPM, k(eff) = 0.006, and optimum gain, 60 signal counts/bit are required at 500 Mbits/s for a 0.000001 bit error probability. It is concluded that QPPM may be an attractive signaling format for some fiber or free space laser communication applications.

  3. Programmable Thermostat Module Upgrade for the Multipurpose Logistics Module

    NASA Technical Reports Server (NTRS)

    Clark, D. W.; Glasgow, S. d.; Reagan, S. E.; Presson, K. H.; Howard, D. E.; Smith, D. A.

    2007-01-01

    The STS-121/ULF 1.1 mission was the maiden flight of the programmable thermostat module (PTM) system used to control the 28 V shell heaters on the multi-purpose logistics module (MPLM). These PTMs, in conjunction with a data recorder module (DRM), provide continuous closed loop temperature control and data recording of MPLM on-orbit heater operations. This Technical Memorandum discusses the hardware design, development, test, and verification (DDT&V) activities performed at the Marshall Space Flight Center as well as the operational implementation and mission performance.

  4. Transmission performance of 20 × 10 Gb/s WDM signals using cascaded optimized SOAs with OOK and DPSK modulation formats

    NASA Astrophysics Data System (ADS)

    Singh, Surinder; Kaler, R. S.

    2006-10-01

    We investigated 20 channels at 10 Gb/s wavelength division multiplexing (WDM) transmission over 1190 km single mode fiber and dispersion compensating fiber using cascaded inline semiconductor optical amplifier at a span of 70 km for RZ-DPSK (return zero differential phase-shift keying) modulation format by using same channel spacing, i.e. 100 GHz. We show for RZ-OOK (return zero on-off keying) format a transmission distance of up to 1050 km with Q factor more than 15 dB, without any power drops. We developed the SOA model for inline amplifier having minimum cross-talks and ASE (amplified spontaneous emission) noise power with sufficient gain. At optimal bias current of 400 mA, a high constant gain of 36.5 dB is obtained up to a saturation power of 21.36 mW. So reduction of cross-talk and distortion is possible by decreasing the bias current at appropriate amplification factor. The DPSK modulation format has less cross-talk as compared to OOK format for nonlinearities and saturation case. The impact of optical power received and Q factor at different distance for both RZ-OOK and RZ-DPSK modulation format has been illustrated. We have shown the optical spectrum and clear Eye diagram at the transmission distance of 1190 km in RZ-DPSK system and 1050 km in RZ-OOK systems. The bit error rate (BER) for all channels observed is less than 10 -10 up to gain saturation for both DPSK and OOK systems. Finally, we investigated that the transmission distance decreases with a decrease in channel spacing of up to 20 GHz.

  5. Average bit error rate performance analysis of subcarrier intensity modulated MRC and EGC FSO systems with dual branches over M distribution turbulence channels

    NASA Astrophysics Data System (ADS)

    Wang, Ran-ran; Wang, Ping; Cao, Tian; Guo, Li-xin; Yang, Yintang

    2015-07-01

    Based on the space diversity reception, the binary phase-shift keying (BPSK) modulated free space optical (FSO) system over Málaga (M) fading channels is investigated in detail. Under independently and identically distributed and independently and non-identically distributed dual branches, the analytical average bit error rate (ABER) expressions in terms of H-Fox function for maximal ratio combining (MRC) and equal gain combining (EGC) diversity techniques are derived, respectively, by transforming the modified Bessel function of the second kind into the integral form of Meijer G-function. Monte Carlo (MC) simulation is also provided to verify the accuracy of the presented models.

  6. "Smart" Sensor Module

    NASA Technical Reports Server (NTRS)

    Mahajan, Ajay

    2007-01-01

    An assembly that contains a sensor, sensor-signal-conditioning circuitry, a sensor-readout analog-to-digital converter (ADC), data-storage circuitry, and a microprocessor that runs special-purpose software and communicates with one or more external computer(s) has been developed as a prototype of "smart" sensor modules for monitoring the integrity and functionality (the "health") of engineering systems. Although these modules are now being designed specifically for use on rocket-engine test stands, it is anticipated that they could also readily be designed to be incorporated into health-monitoring subsystems of such diverse engineering systems as spacecraft, aircraft, land vehicles, bridges, buildings, power plants, oilrigs, and defense installations. The figure is a simplified block diagram of the "smart" sensor module. The analog sensor readout signal is processed by the ADC, the digital output of which is fed to the microprocessor. By means of a standard RS-232 cable, the microprocessor is connected to a local personal computer (PC), from which software is downloaded into a randomaccess memory in the microprocessor. The local PC is also used to debug the software. Once the software is running, the local PC is disconnected and the module is controlled by, and all output data from the module are collected by, a remote PC via an Ethernet bus. Several smart sensor modules like this one could be connected to the same Ethernet bus and controlled by the single remote PC. The software running in the microprocessor includes driver programs for operation of the sensor, programs that implement self-assessment algorithms, programs that implement protocols for communication with the external computer( s), and programs that implement evolutionary methodologies to enable the module to improve its performance over time. The design of the module and of the health-monitoring system of which it is a part reflects the understanding that the main purpose of a health

  7. Parabolic dish module experiment

    NASA Astrophysics Data System (ADS)

    1986-03-01

    A development test model of the 8-meter Solar Brayton Parabolic Dish Module has been designed, fabricated, and tested. The test model consists of five major subsystems: Sanders ceramic honeycomb solar receiver; LaJet LEC460 solar concentrator; AiRsearch SABC MKIIIA engine, Abacus 8 kW ac inverter; and a Sanders designed and built system controller. Goals of the tests were to integrate subsystem components into a working module, demonstrate the concept, and generate 5 kWe (hybrid) and 4.7 kWe (solar only) input. All subsystem integration goals were successfully achieved, but system performance efficiency was lower than expected. Contributing causes of the lower performance efficiencies have been identified. Modifications needed to restore performance to the required levels and improve the system life cycle cost have been addressed and are the subject of this final report.

  8. Module voltage isolation and corrosion research

    NASA Technical Reports Server (NTRS)

    Mon, G. R.

    1985-01-01

    A summary of recent research at JPL on two topics related to achieving long term reliability of photovoltaic modules: voltage isolation and electrochemical corrosion is presented. Special emphasis is given to similarities and differences in performance between crystalline silicon modules and amorphous silicon modules.

  9. Firefighting Module

    NASA Astrophysics Data System (ADS)

    1984-01-01

    Firefly II pump module is NASA's Marshall Space Flight Center's commercial offshoot of a NASA/US Coast Guard program involving development of a lightweight, helicopter-transportable firefighting module for a quick response in combating shipboard or harbor fires. Operable on land or water, the Amphib One is equipped with 3 water cannons. When all 3 are operating, unit pumps more than 3,000 gallons a minute. Newly developed model used by U.S. Coast Guard can pump 5,000 gallons per minute. It was designed for applications such as firefighting onboard ship fires, emergency dockside water pumping, dewatering ships in danger of sinking, flood control, and emergency water supply at remote locations.

  10. Thermoelectric module

    DOEpatents

    Kortier, William E.; Mueller, John J.; Eggers, Philip E.

    1980-07-08

    A thermoelectric module containing lead telluride as the thermoelectric mrial is encapsulated as tightly as possible in a stainless steel canister to provide minimum void volume in the canister. The lead telluride thermoelectric elements are pressure-contacted to a tungsten hot strap and metallurgically bonded at the cold junction to iron shoes with a barrier layer of tin telluride between the iron shoe and the p-type lead telluride element.

  11. Photovoltaic concentrator module improvements study

    SciTech Connect

    Levy, S.L.; Kerschen, K.A. ); Hutchison, G. ); Nowlan, M.J. )

    1991-08-01

    This report presents results of a project to design and fabricate an improved photovoltaic concentrator module. Using previous work as a baseline, this study conducted analyses and testing to select major module components and design features. The lens parquet and concentrator solar cell were selected from the highest performing, available components. A single 185X point-focus module was fabricated by the project team and tested at Sandia. Major module characteristics include a 6 by 4 compression-molded acrylic lens parquet (0.737 m{sup 2} area), twenty-four 0.2 ohms-cm, FZ, p-Si solar cells (1.56 cm{sup 2} area) soldered to ceramic substrates and copper heat spreaders, and an aluminized steel housing with corrugated bottom. This project marked the first attempt to use prismatic covers on solar cells in a high-concentration, point-focus application. Cells with 15 percent metallization were obtained, but problems with the fabrication and placement of prismatic covers on these cells lead to the decision not to use covers in the prototype module. Cell assembly fabrication, module fabrication, and module optical design activities are presented here. Test results are also presented for bare cells, cell assemblies, and module. At operating conditions of 981 watts/m{sup 2} DNI and an estimated cell temperature of 65{degrees}C, the module demonstrated an efficiency of 13.9 percent prior to stressed environmental exposure. 12 refs., 56 figs., 7 tabs.

  12. SCALE: A modular code system for performing Standardized Computer Analyses for Licensing Evaluation. Volume 2, Part 3: Functional modules F16--F17; Revision 5

    SciTech Connect

    1997-03-01

    SCALE--a modular code system for Standardized Computer Analyses Licensing Evaluation--has been developed by Oak Ridge National Laboratory at the request of the US Nuclear Regulatory Commission. The SCALE system utilizes well-established computer codes and methods within standard analysis sequences that (1) allow an input format designed for the occasional user and/or novice, (2) automated the data processing and coupling between modules, and (3) provide accurate and reliable results. System development has been directed at problem-dependent cross-section processing and analysis of criticality safety, shielding, heat transfer, and depletion/decay problems. Since the initial release of SCALE in 1980, the code system has been heavily used for evaluation of nuclear fuel facility and package designs. This revision documents Version 4.3 of the system.

  13. SCALE: A modular code system for performing Standardized Computer Analyses for Licensing Evaluation. Volume 1, Part 2: Control modules S1--H1; Revision 5

    SciTech Connect

    1997-03-01

    SCALE--a modular code system for Standardized Computer Analyses Licensing Evaluation--has been developed by Oak Ridge National Laboratory at the request of the US Nuclear Regulatory Commission. The SCALE system utilizes well-established computer codes and methods within standard analysis sequences that (1) allow an input format designed for the occasional user and/or novice, (2) automated the data processing and coupling between modules, and (3) provide accurate and reliable results. System development has been directed at problem-dependent cross-section processing and analysis of criticality safety, shielding, heat transfer, and depletion/decay problems. Since the initial release of SCALE in 1980, the code system has been heavily used for evaluation of nuclear fuel facility and package designs. This revision documents Version 4.3 of the system.

  14. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Lenox, Carl J. S.; Culligan, Matthew; Danning, Matt

    2013-08-27

    A photovoltaic (PV) module including a PV device and a frame, The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  15. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Lenox, Carl J. S.; Culligan, Matthew; Danning, Matt

    2012-07-17

    A photovoltaic (PV) module including a PV device and a frame. The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  16. Displacement damage in bit error ratio performance of on-off keying, pulse position modulation, differential phase shift keying, and homodyne binary phase-shift keying-based optical intersatellite communication system.

    PubMed

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Dong, Chen; Li, Xuan

    2016-04-10

    Displacement damage (DD) effect induced bit error ratio (BER) performance degradations in on-off keying (OOK), pulse position modulation (PPM), differential phase-shift keying (DPSK), and homodyne binary phase shift keying (BPSK) based systems were simulated and discussed under 1 MeV neutron irradiation to a total fluence of 1×1012  n/cm2 in this paper. Degradation of main optoelectronic devices included in communication systems were analyzed on the basis of existing experimental data. The system BER degradation was subsequently simulated and the variations of BER with different neutron irradiation location were also achieved. The result shows that DD on an Er-doped fiber amplifier (EDFA) is the dominant cause of system degradation, and a BPSK-based system performs better than the other three systems against DD. In order to improve radiation hardness of communication systems against DD, protection and enhancement of EDFA are required, and the use of a homodyne BPSK modulation scheme is a considered choice.

  17. Trying to Put the Puzzle Together: Age and Performance Level Modulate the Neural Response to Increasing Task Load within Left Rostral Prefrontal Cortex.

    PubMed

    Bauer, Eva; Sammer, Gebhard; Toepper, Max

    2015-01-01

    Age-related working memory decline is associated with functional cerebral changes within prefrontal cortex (PFC). Kind and meaning of these changes are heavily discussed since they depend on performance level and task load. Hence, we investigated the effects of age, performance level, and load on spatial working memory retrieval-related brain activation in different subregions of the PFC. 19 younger (Y) and 21 older (O) adults who were further subdivided into high performers (HP) and low performers (LP) performed a modified version of the Corsi Block-Tapping test during fMRI. Brain data was analyzed by a 4 (groups: YHP, OHP, YLP, and OLP) × 3 (load levels: loads 4, 5, and 6) ANOVA. Results revealed significant group × load interaction effects within rostral dorsolateral and ventrolateral PFC. YHP showed a flexible neural upregulation with increasing load, whereas YLP reached a resource ceiling at a moderate load level. OHP showed a similar (though less intense) pattern as YHP and may have compensated age-effects at high task load. OLP showed neural inefficiency at low and no upregulation at higher load. Our findings highlight the relevance of age and performance level for load-dependent activation within rostral PFC. Results are discussed in the context of the compensation-related utilization of neural circuits hypothesis (CRUNCH) and functional PFC organization.

  18. Photovoltaic module energy rating methodology development

    SciTech Connect

    Kroposki, B.; Myers, D.; Emery, K.; Mrig, L.; Whitaker, C.; Newmiller, J.

    1996-05-01

    A consensus-based methodology to calculate the energy output of a PV module will be described in this paper. The methodology develops a simple measure of PV module performance that provides for a realistic estimate of how a module will perform in specific applications. The approach makes use of the weather data profiles that describe conditions throughout the United States and emphasizes performance differences between various module types. An industry-representative Technical Review Committee has been assembled to provide feedback and guidance on the strawman and final approach used in developing the methodology.

  19. Electrical and optical performance characteristics of 0.74eV p/n InGaAs monolithic interconnected modules

    SciTech Connect

    Wilt, D.M.; Weizer, V.G.; Fatemi, N.S.; Jenkins, P.P.; Hoffman, R.W. Jr.; Jain, R.K.; Murray, C.S.; Riley, D.R.

    1997-06-01

    There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between system efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) cells series-connected on a single semi-insulating indium phosphide (InP) substrate. The MIM is exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 cm{sup 2} device consisting of eight series interconnected cells. MIM devices, produced from 0.74 eV InGaAs, have demonstrated V{sub oc} = 3.2 volts, J{sub sc} = 70 mA/cm{sup 2} and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurements (> 2 {micro}m) of these devices indicate a reflectivity of > 82%. MIM devices produced from 0.55 eV InGaAs have also been demonstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM0) have been demonstrated.

  20. Electrical and Optical Performance Characteristics of 0.74-eV p/n InGaAs Monolithic Interconnected Modules

    NASA Technical Reports Server (NTRS)

    Wilt, David M.; Fatemi, Navid S.; Jenkins, Phillip P.; Weizer, Victor G.; Hoffman, Richard W., Jr.; Jain, Raj K.; Murray, Christopher S.; Riley, David R.

    1997-01-01

    There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between system efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) cells series-connected on a single semi-insulating indium phosphide (InP) substrate. The MIM is exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 sq cm device consisting of eight (8) series interconnected cells. MIM devices, produced from 0.74-eV InGaAs, have demonstrated V(sub oc) = 3.2 volts, J(sub sc) = 70 mA/sq cm, and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurements (greater than 2 micron) of these devices indicate a reflectivity of greater than 82%. MIM devices produced from 0.55-eV InGaAs have also been demonstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM0) have been demonstrated.

  1. Variable Coded Modulation software simulation

    NASA Astrophysics Data System (ADS)

    Sielicki, Thomas A.; Hamkins, Jon; Thorsen, Denise

    This paper reports on the design and performance of a new Variable Coded Modulation (VCM) system. This VCM system comprises eight of NASA's recommended codes from the Consultative Committee for Space Data Systems (CCSDS) standards, including four turbo and four AR4JA/C2 low-density parity-check codes, together with six modulations types (BPSK, QPSK, 8-PSK, 16-APSK, 32-APSK, 64-APSK). The signaling protocol for the transmission mode is based on a CCSDS recommendation. The coded modulation may be dynamically chosen, block to block, to optimize throughput.

  2. Student Engagement Patterns over the Duration of Level 1 and Level 3 Geography Modules: Influences on Student Attendance, Performance and Use of Online Resources

    ERIC Educational Resources Information Center

    Stewart, Martyn; Stott, Tim; Nuttall, Anne-Marie

    2011-01-01

    Greater flexibility in delivery resulting from increased use of e-learning will inevitably change the way university students approach studying. Recent studies have examined relationships between attendance, online learning and performance but findings are inconclusive. One concern is that an unintended consequence of placing lecture resources…

  3. Dehydrated citrus pulp alters feedlot performance of crossbred heifers during the receiving period and modulates serum metabolite concentrations pre- and post-endotoxin challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    English x Continental heifers (n=180) were sourced in two loads (188.7 ± 18.0 kilograms and 225.2 ± 22.2 kilograms body weight, respectively) from commercial auction barns to study the effects of feeding dehydrated citrus pulp (DCP) on feedlot performance of newly received heifers. A completely ran...

  4. The Effect of Computer Assisted Language Learning (CALL) on Performance in the Test of English for International Communication (TOEIC) Listening Module

    ERIC Educational Resources Information Center

    van Han, Nguyen; van Rensburg, Henriette

    2014-01-01

    Many companies and organizations have been using the Test of English for International Communication (TOEIC) for business and commercial communication purpose in Vietnam and around the world. The present study investigated the effect of Computer Assisted Language Learning (CALL) on performance in the Test of English for International Communication…

  5. 10 ps resolution, 160 ns full scale range and less than 1.5% differential non-linearity time-to-digital converter module for high performance timing measurements

    SciTech Connect

    Markovic, B.; Tamborini, D.; Villa, F.; Tisa, S.; Tosi, A.; Zappa, F.

    2012-07-15

    We present a compact high performance time-to-digital converter (TDC) module that provides 10 ps timing resolution, 160 ns dynamic range and a differential non-linearity better than 1.5% LSB{sub rms}. The TDC can be operated either as a general-purpose time-interval measurement device, when receiving external START and STOP pulses, or in photon-timing mode, when employing the on-chip SPAD (single photon avalanche diode) detector for detecting photons and time-tagging them. The instrument precision is 15 ps{sub rms} (i.e., 36 ps{sub FWHM}) and in photon timing mode it is still better than 70 ps{sub FWHM}. The USB link to the remote PC allows the easy setting of measurement parameters, the fast download of acquired data, and their visualization and storing via an user-friendly software interface. The module proves to be the best candidate for a wide variety of applications such as: fluorescence lifetime imaging, time-of-flight ranging measurements, time-resolved positron emission tomography, single-molecule spectroscopy, fluorescence correlation spectroscopy, diffuse optical tomography, optical time-domain reflectometry, quantum optics, etc.

  6. 10 ps resolution, 160 ns full scale range and less than 1.5% differential non-linearity time-to-digital converter module for high performance timing measurements

    NASA Astrophysics Data System (ADS)

    Markovic, B.; Tamborini, D.; Villa, F.; Tisa, S.; Tosi, A.; Zappa, F.

    2012-07-01

    We present a compact high performance time-to-digital converter (TDC) module that provides 10 ps timing resolution, 160 ns dynamic range and a differential non-linearity better than 1.5% LSBrms. The TDC can be operated either as a general-purpose time-interval measurement device, when receiving external START and STOP pulses, or in photon-timing mode, when employing the on-chip SPAD (single photon avalanche diode) detector for detecting photons and time-tagging them. The instrument precision is 15 psrms (i.e., 36 psFWHM) and in photon timing mode it is still better than 70 psFWHM. The USB link to the remote PC allows the easy setting of measurement parameters, the fast download of acquired data, and their visualization and storing via an user-friendly software interface. The module proves to be the best candidate for a wide variety of applications such as: fluorescence lifetime imaging, time-of-flight ranging measurements, time-resolved positron emission tomography, single-molecule spectroscopy, fluorescence correlation spectroscopy, diffuse optical tomography, optical time-domain reflectometry, quantum optics, etc.

  7. 10 ps resolution, 160 ns full scale range and less than 1.5% differential non-linearity time-to-digital converter module for high performance timing measurements.

    PubMed

    Markovic, B; Tamborini, D; Villa, F; Tisa, S; Tosi, A; Zappa, F

    2012-07-01

    We present a compact high performance time-to-digital converter (TDC) module that provides 10 ps timing resolution, 160 ns dynamic range and a differential non-linearity better than 1.5% LSB(rms). The TDC can be operated either as a general-purpose time-interval measurement device, when receiving external START and STOP pulses, or in photon-timing mode, when employing the on-chip SPAD (single photon avalanche diode) detector for detecting photons and time-tagging them. The instrument precision is 15 ps(rms) (i.e., 36 ps(FWHM)) and in photon timing mode it is still better than 70 ps(FWHM). The USB link to the remote PC allows the easy setting of measurement parameters, the fast download of acquired data, and their visualization and storing via an user-friendly software interface. The module proves to be the best candidate for a wide variety of applications such as: fluorescence lifetime imaging, time-of-flight ranging measurements, time-resolved positron emission tomography, single-molecule spectroscopy, fluorescence correlation spectroscopy, diffuse optical tomography, optical time-domain reflectometry, quantum optics, etc. PMID:22852708

  8. Management and Family Economics Student Modules.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Home Economics Education Section.

    This document contains 73 performance-based modules for student use in high school home management and family economics courses. Each module is composed of an introduction for the student, a performance objective, a variety of learning activities, content information, a student self-check, recommended references, and an evaluator's final…

  9. Securing a Training Site. Self-Paced Instructional Module. Module Number V-B.

    ERIC Educational Resources Information Center

    King, Sylvester; Brooks, Kent

    One of 33 self-paced instructional modules for training industry services leaders to provide guidance in the performance of manpower services by public agencies to new and expanding private industry, this module contains three sequential learning activities on securing a training site. (Three of the other modules deal with other tasks also…

  10. Photovoltaic array performance model.

    SciTech Connect

    Kratochvil, Jay A.; Boyson, William Earl; King, David L.

    2004-08-01

    This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

  11. Vapor compression distillation module

    NASA Technical Reports Server (NTRS)

    Nuccio, P. P.

    1975-01-01

    A Vapor Compression Distillation (VCD) module was developed and evaluated as part of a Space Station Prototype (SSP) environmental control and life support system. The VCD module includes the waste tankage, pumps, post-treatment cells, automatic controls and fault detection instrumentation. Development problems were encountered with two components: the liquid pumps, and the waste tank and quantity gauge. Peristaltic pumps were selected instead of gear pumps, and a sub-program of materials and design optimization was undertaken leading to a projected life greater than 10,000 hours of continuous operation. A bladder tank was designed and built to contain the waste liquids and deliver it to the processor. A detrimental pressure pattern imposed upon the bladder by a force-operated quantity gauge was corrected by rearranging the force application, and design goals were achieved. System testing has demonstrated that all performance goals have been fulfilled.

  12. VERDE Analytic Modules

    2008-01-15

    The Verde Analytic Modules permit the user to ingest openly available data feeds about phenomenology (storm tracks, wind, precipitation, earthquake, wildfires, and similar natural and manmade power grid disruptions and forecast power outages, restoration times, customers outaged, and key facilities that will lose power. Damage areas are predicted using historic damage criteria of the affected area. The modules use a cellular automata approach to estimating the distribution circuits assigned to geo-located substations. Population estimates servedmore » within the service areas are located within 1 km grid cells and converted to customer counts by conversion through demographic estimation of households and commercial firms within the population cells. Restoration times are estimated by agent-based simulation of restoration crews working according to utility published prioritization calibrated by historic performance.« less

  13. VERDE Analytic Modules

    SciTech Connect

    2008-01-15

    The Verde Analytic Modules permit the user to ingest openly available data feeds about phenomenology (storm tracks, wind, precipitation, earthquake, wildfires, and similar natural and manmade power grid disruptions and forecast power outages, restoration times, customers outaged, and key facilities that will lose power. Damage areas are predicted using historic damage criteria of the affected area. The modules use a cellular automata approach to estimating the distribution circuits assigned to geo-located substations. Population estimates served within the service areas are located within 1 km grid cells and converted to customer counts by conversion through demographic estimation of households and commercial firms within the population cells. Restoration times are estimated by agent-based simulation of restoration crews working according to utility published prioritization calibrated by historic performance.

  14. Modulation of mood and cognitive performance following acute administration of single doses of Melissa officinalis (Lemon balm) with human CNS nicotinic and muscarinic receptor-binding properties.

    PubMed

    Kennedy, D O; Wake, G; Savelev, S; Tildesley, N T J; Perry, E K; Wesnes, K A; Scholey, A B

    2003-10-01

    Melissa officinalis (Lemon balm) is a herbal medicine that has traditionally been attributed with memory-enhancing properties, but which is currently more widely used as a mild sedative and sleep aid. In a previous study it was demonstrated that a commercial Melissa extract led to dose-specific increases in calmness, and dose-dependent decrements in timed memory task performance. However, the extract utilized in that study did not exhibit in vitro cholinergic receptor-binding properties. The current study involved an initial screening of samples of M. officinalis for human acetylcholinesterase inhibition and cholinergic receptor-binding properties. The cognitive and mood effects of single doses of the most cholinergically active dried leaf were then assessed in a randomized, placebo-controlled, double-blind, balanced crossover study. Following the in vitro analysis, 20 healthy, young participants received single doses of 600, 1000, and 1600 mg of encapsulated dried leaf, or a matching placebo, at 7-day intervals. Cognitive performance and mood were assessed predose and at 1, 3, and 6 h postdose using the Cognitive Drug Research computerized assessment battery and Bond-Lader visual analog scales, respectively. In vitro analysis of the chosen extract established IC(50) concentrations of 0.18 and 3.47 mg ml(-1), respectively, for the displacement of [(3)H]-(N)-nicotine and [(3)H]-(N)-scopolamine from nicotinic and muscarinic receptors in the human cerebral cortex tissue. However, no cholinesterase inhibitory properties were detected. The most notable cognitive and mood effects were improved memory performance and increased 'calmness' at all postdose time points for the highest (1600 mg) dose. However, while the profile of results was overwhelmingly favorable for the highest dose, decrements in the speed of timed memory task performance and on a rapid visual information-processing task increased with decreasing dose. These results suggest that doses of Melissa

  15. Performance evaluation and comparative analysis of SubCarrier Modulation Wake-up Radio systems for energy-efficient wireless sensor networks.

    PubMed

    Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

    2013-12-19

    Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications.

  16. Performance evaluation and comparative analysis of SubCarrier Modulation Wake-up Radio systems for energy-efficient wireless sensor networks.

    PubMed

    Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

    2013-01-01

    Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications. PMID:24451452

  17. Performance Evaluation and Comparative Analysis of SubCarrier Modulation Wake-up Radio Systems for Energy-Efficient Wireless Sensor Networks

    PubMed Central

    Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

    2014-01-01

    Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications. PMID:24451452

  18. Long wave focal plane array detector: development and performance assessment of an 8X8 Sterling cooled photovoltaic MCT detector module

    NASA Astrophysics Data System (ADS)

    Rochette, Luc; Smithson, Tracy; Gurgenian, Raymond; St. Pierre, Guy

    2007-09-01

    In June 2005, a newly develop long wave Focal Pane Array (FPA), based on photo-voltaic technology was delivered to the Defense Research & Development of Canada (DRDC). This development was part of technological Demonstration program that was founded by the DRDC. This paper will describe the FPA configuration along with its performance assessment configured in the Air PIRATE FTIR spectrometer. Air PIRATE is an airborne version of the hyper spectral spectrometer used by the Canadian Defense for target identification, as well as chemical agent identification.

  19. Supported PV module assembly

    DOEpatents

    Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

    2013-10-15

    A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

  20. Effect of flame stabilizer design on performance and exhaust pollutants of a two-row 72-module swirl-can combustor

    NASA Technical Reports Server (NTRS)

    Biaglow, J. A.; Trout, A. M.

    1976-01-01

    A test program was conducted to evaluate the effects of four flame stabilizer designs on the performance and gaseous pollutant levels of an experimental full-annular swirl-can combustor. Combustor operating parameters, including inlet-air temperature, reference velocity, and fuel-air ratio, were set to simulate conditions in a 30:1 pressure ratio engine. Combustor inlet total pressure was held constant at 6 atm due to the facility limit. Combustor performance and gaseous pollutant levels were strongly affected by the geometry and resulting total pressure loss of the four flame stabilizer designs investigated. The addition of shrouds to two designs produced an 18 to 22% decrease in the combustion chamber pressure loss and thus resulted in doubling the exit temperature pattern factor and up to 42% higher levels of oxides of nitrogen. A previously developed oxides of nitrogen correlating parameter agreed with each model within an emission index of plus or minus 1 but was not capable of correlating all models together.

  1. A roundabout approach to control morphological orientation and solar-cell performance by modulating side-chain branching position in benzodithiophene-based polymers.

    PubMed

    Lee, Kyu Cheol; Song, Seyeong; Lee, Junghoon; Kim, Dong Suk; Kim, Jin Young; Yang, Changduk

    2015-04-27

    To be meaningful to guide the rational design of novel high-performance conjugated semiconductors, we prepared three benzo[1,2-b:4,5-b']dithiophene (BDT)-based polymers by systematically moving the branching point of the alkyl chain. The effect of side-chain engineering was thoroughly investigated by a range of techniques. We demonstrate that a subtle change in the branching position in the BDT core can have a critical impact on polymer packing and preferential backbone orientation in thin films; copolymers made from BDT and thieno[3,4-c]pyrrole-4,6-dione units (TPD) adopt more of a face-on orientation as the branching point is shifted closer to the backbone, which can be correlated with a dramatic difference in solar-cells performance. The high short-circuit current density (11.6 mA cm(-2) ) for the copolymer with one carbon atom between the alkoxylated oxygen atom and the branching point results from its predominantly face-on orientation and smoother surface in thin films, which results in power conversion efficiencies as high as 4.56 %.

  2. Reaction mechanism of a PbS-on-ZnO heterostructure and enhanced photovoltaic diode performance with an interface-modulated heterojunction energy band structure.

    PubMed

    Li, Haili; Jiao, Shujie; Ren, Jinxian; Li, Hongtao; Gao, Shiyong; Wang, Jinzhong; Wang, Dongbo; Yu, Qingjiang; Zhang, Yong; Li, Lin

    2016-02-01

    A room temperature successive ionic layer adsorption and reaction (SILAR) method is introduced for fabricating quantum dots-on-wide bandgap semiconductors. Detailed exploration of how SILAR begins and proceeds is performed by analyzing changes in the electronic structure of related elements at interfaces by X-ray photoelectric spectroscopy, together with characterization of optical properties and X-ray diffraction. The distribution of PbS QDs on ZnO, which is critical for optoelectrical applications of PbS with a large dielectric constant, shows a close relationship with the dipping order. A successively deposited PbS QDs layer is obtained when the sample is first immersed in Na2S solution. This is reasonable because the initial formation of different chemical bonds on ZnO nanorods is closely related to dangling bonds and defect states on surfaces. Most importantly, dipping order also affects their optoelectrical characteristics greatly, which can be explained by the heterojunction energy band structure related to the interface. The formation mechanism for PbS QDs on ZnO is confirmed by the fact that the photovoltaic diode device performance is closely related to the dipping order. Our atomic-scale understanding emphasises the fundamental role of surface chemistry in the structure and tuning of optoelectrical properties, and consequently in devices.

  3. Brain-Derived Neurotrophic Factor (Val66Met) and Serotonin Transporter (5-HTTLPR) Polymorphisms Modulate Plasticity in Inhibitory Control Performance Over Time but Independent of Inhibitory Control Training.

    PubMed

    Enge, Sören; Fleischhauer, Monika; Gärtner, Anne; Reif, Andreas; Lesch, Klaus-Peter; Kliegel, Matthias; Strobel, Alexander

    2016-01-01

    Several studies reported training-induced improvements in executive function tasks and also observed transfer to untrained tasks. However, the results are mixed and there is a large interindividual variability within and across studies. Given that training-related performance changes would require modification, growth or differentiation at the cellular and synaptic level in the brain, research on critical moderators of brain plasticity potentially explaining such changes is needed. In the present study, a pre-post-follow-up design (N = 122) and a 3-weeks training of two response inhibition tasks (Go/NoGo and Stop-Signal) was employed and genetic variation (Val66Met) in the brain-derived neurotrophic factor (BDNF) promoting differentiation and activity-dependent synaptic plasticity was examined. Because Serotonin (5-HT) signaling and the interplay of BDNF and 5-HT are known to critically mediate brain plasticity, genetic variation in the 5-HTT gene-linked polymorphic region (5-HTTLPR) was also addressed. The overall results show that the kind of training (i.e., adaptive vs. non-adaptive) did not evoke genotype-dependent differences. However, in the Go/NoGo task, better inhibition performance (lower commission errors) were observed for BDNF Val/Val genotype carriers compared to Met-allele ones supporting similar findings from other cognitive tasks. Additionally, a gene-gene interaction suggests a more impulsive response pattern (faster responses accompanied by higher commission error rates) in homozygous l-allele carriers relative to those with the s-allele of 5-HTTLPR. This, however, is true only in the presence of the Met-allele of BDNF, while the Val/Val genotype seems to compensate for such non-adaptive responding. Intriguingly, similar results were obtained for the Stop-Signal task. Here, differences emerged at post-testing, while no differences were observed at T1. In sum, although no genotype-dependent differences between the relevant training groups emerged

  4. Brain-Derived Neurotrophic Factor (Val66Met) and Serotonin Transporter (5-HTTLPR) Polymorphisms Modulate Plasticity in Inhibitory Control Performance Over Time but Independent of Inhibitory Control Training

    PubMed Central

    Enge, Sören; Fleischhauer, Monika; Gärtner, Anne; Reif, Andreas; Lesch, Klaus-Peter; Kliegel, Matthias; Strobel, Alexander

    2016-01-01

    Several studies reported training-induced improvements in executive function tasks and also observed transfer to untrained tasks. However, the results are mixed and there is a large interindividual variability within and across studies. Given that training-related performance changes would require modification, growth or differentiation at the cellular and synaptic level in the brain, research on critical moderators of brain plasticity potentially explaining such changes is needed. In the present study, a pre-post-follow-up design (N = 122) and a 3-weeks training of two response inhibition tasks (Go/NoGo and Stop-Signal) was employed and genetic variation (Val66Met) in the brain-derived neurotrophic factor (BDNF) promoting differentiation and activity-dependent synaptic plasticity was examined. Because Serotonin (5-HT) signaling and the interplay of BDNF and 5-HT are known to critically mediate brain plasticity, genetic variation in the 5-HTT gene-linked polymorphic region (5-HTTLPR) was also addressed. The overall results show that the kind of training (i.e., adaptive vs. non-adaptive) did not evoke genotype-dependent differences. However, in the Go/NoGo task, better inhibition performance (lower commission errors) were observed for BDNF Val/Val genotype carriers compared to Met-allele ones supporting similar findings from other cognitive tasks. Additionally, a gene-gene interaction suggests a more impulsive response pattern (faster responses accompanied by higher commission error rates) in homozygous l-allele carriers relative to those with the s-allele of 5-HTTLPR. This, however, is true only in the presence of the Met-allele of BDNF, while the Val/Val genotype seems to compensate for such non-adaptive responding. Intriguingly, similar results were obtained for the Stop-Signal task. Here, differences emerged at post-testing, while no differences were observed at T1. In sum, although no genotype-dependent differences between the relevant training groups emerged

  5. Chronic Mild Cold Conditioning Modulates the Expression of Hypothalamic Neuropeptide and Intermediary Metabolic-Related Genes and Improves Growth Performances in Young Chicks

    PubMed Central

    Nguyen, Phuong; Greene, Elizabeth; Ishola, Peter; Huff, Geraldine; Donoghue, Annie; Bottje, Walter; Dridi, Sami

    2015-01-01

    Background Low environmental temperatures are among the most challenging stressors in poultry industries. Although landmark studies using acute severe cold exposure have been conducted, still the molecular mechanisms underlying cold-stress responses in birds are not completely defined. In the present study we determine the effect of chronic mild cold conditioning (CMCC) on growth performances and on the expression of key metabolic-related genes in three metabolically important tissues: brain (main site for feed intake control), liver (main site for lipogenesis) and muscle (main site for thermogenesis). Methods 80 one-day old male broiler chicks were divided into two weight-matched groups and maintained in two different temperature floor pen rooms (40 birds/room). The temperature of control room was 32°C, while the cold room temperature started at 26.7°C and gradually reduced every day (1°C/day) to reach 19.7°C at the seventh day of the experiment. At day 7, growth performances were recorded (from all birds) and blood samples and tissues were collected (n = 10). The rest of birds were maintained at the same standard environmental condition for two more weeks and growth performances were measured. Results Although feed intake remained unchanged, body weight gain was significantly increased in CMCC compared to the control chicks resulting in a significant low feed conversion ratio (FCR). Circulating cholesterol and creatine kinase levels were higher in CMCC chicks compared to the control group (P<0.05). CMCC significantly decreased the expression of both the hypothalamic orexigenic neuropeptide Y (NPY) and anorexigenic cocaine and amphetamine regulated transcript (CART) in chick brain which may explain the similar feed intake between the two groups. Compared to the control condition, CMCC increased the mRNA abundance of AMPKα1/α2 and decreased mTOR gene expression (P<0.05), the master energy and nutrient sensors, respectively. It also significantly decreased the

  6. Experimental performance comparison of duobinary and PSBT modulation formats for long-haul 40 Gb/s transmission on G 0.652 fibre.

    PubMed

    Pincemin, Erwan; Gosset, Christophe; Boudrioua, Nassima; Tan, Antoine; Grot, Didier; Guillossou, Thierry

    2012-12-17

    Duobinary formats are today considered as being one of the most promising cost-effective solutions for the deployment of 40 Gb/s technology with direct detection on existing 10 Gb/s WDM long-haul (metropolitan and core) transmission infrastructures. Various methods for generating duobinary formats have been developed in the past few years but to our knowledge their respective performances for 40 Gb/s transmission have never been really compared experimentally. Here, we propose to evaluate at 40 Gb/s their respective robustness with respect to the most stringent transmission impairments, namely ASE noise, chromatic dispersion, polarization mode dispersion and nonlinear effects. We demonstrate that, owing to its enhanced resistance to intra-channel nonlinearities as compared to non-return-to-zero, duobinary can permit to reach transmission distances compliant with metropolitan and core applications on G.652 standard single mode fibre when quasi single-channel transmission conditions are met. We show furthermore that shifting optical duobinary filtering from the transmitter output to the receiver input can be of high interest to improve further the system maximum reach. We show also that phase-shaped binary transmission (PSBT) formats are fully compliant with 50-GHz channel spacing and that they are, in terms of transmission performance, as good as partial differential phase shift keying (Partial-DPSK), which is considered by equipment suppliers as the preferential transport solution for deployment of 40 Gb/s technology with direct detection on existing 10 Gb/s WDM metropolitan and core transmission infrastructures.

  7. A Methodology to Teach Advanced A/D Converters, Combining Digital Signal Processing and Microelectronics Perspectives

    ERIC Educational Resources Information Center

    Quintans, C.; Colmenar, A.; Castro, M.; Moure, M. J.; Mandado, E.

    2010-01-01

    ADCs (analog-to-digital converters), especially Pipeline and Sigma-Delta converters, are designed using complex architectures in order to increase their sampling rate and/or resolution. Consequently, the learning of ADC devices also encompasses complex concepts such as multistage synchronization, latency, oversampling, modulation, noise shaping,…

  8. Solid State Marx Modulators for Emerging Applications

    SciTech Connect

    Kemp, M.A.; /SLAC

    2012-09-14

    Emerging linear accelerator applications increasingly push the boundaries of RF system performance and economics. The power modulator is an integral part of RF systems whose characteristics play a key role in the determining parameters such as efficiency, footprint, cost, stability, and availability. Particularly within the past decade, solid-state switch based modulators have become the standard in high-performance, high power modulators. One topology, the Marx modulator, has characteristics which make it particularly attractive for several emerging applications. This paper is an overview of the Marx topology, some recent developments, and a case study of how this architecture can be applied to a few proposed linear accelerators.

  9. Lunar Module Ascent Stage

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The Lunar Module 'Spider' ascent stage is photographed from the Command/Service Module on the fifth day of the Apollo 9 earth-orbital mission. The Lunar Module's descent stage had already been jettisoned.

  10. Structural modulation of lithium metal-electrolyte interface with three-dimensional metallic interlayer for high-performance lithium metal batteries.

    PubMed

    Lee, Hongkyung; Song, Jongchan; Kim, Yun-Jung; Park, Jung-Ki; Kim, Hee-Tak

    2016-01-01

    The use of lithium (Li) metal anodes has been reconsidered because of the necessity for a higher energy density in secondary batteries. However, Li metal anodes suffer from 'dead' Li formation and surface deactivation which consequently form a porous layer of redundant Li aggregates. In this work, a fibrous metal felt (FMF) as a three-dimensional conductive interlayer was introduced between the separator and the Li metal anode to improve the reversibility of the Li metal anode. The FMF can facilitate charge transfer in the porous layer, rendering it electrochemically more active. In addition, the FMF acted as a robust scaffold to accommodate Li deposits compactly in its interstitial sites. The FMF-integrated Li metal (FMF/Li) electrode operated with a small polarisation even at a current density of 10 mA cm(-2), and it exhibited a seven times longer cycle-life than that of an FMF-free Li electrode in a symmetric cell configuration. A Li metal battery (LMB) using the FMF/Li electrode and a LiFePO4 electrode exhibited a two-fold increase in cycling stability compared with that of a bare Li metal electrode, demonstrating the practical effectiveness of this approach for high performance LMBs. PMID:27484160

  11. Pseudomorphic InGaAs/AlGaAs modulation-doped FET's with reduced low-frequency noise and thermally stable performance

    NASA Technical Reports Server (NTRS)

    Liu, Shih-Ming; Das, M. B.; Peng, C. K.; Klem, J.; Henderson, T.

    1987-01-01

    A high-performance MODFET structure grown by MBE with the incorporation of a single quantum well In(0.15)Ga(0.85)As layer for the transport of two-dimensional electron gas has been critically examined for its thermal stability at 80 K and low-frequency noise form 0.01 to 10 to the 8th Hz. Experimental results indicate that the behavior of this device in both these respects is much superior when compared with the same behavior of conventional MODFETs. A maximum low-field carrier mobility of 29,000 sq cm/s at 80 K and an average carrier saturation velocity of 2 x 10 to the 7th cm/s at 300 K in a 1-micron gate device clearly indicate that the quality of the pseudomorphic quantum well (InGaAs) layer is either comparable or better than that of the usual GaAs buffer layer. The deep level spectra, obtained through photo-FET measurements, and the low-frequency noise spectra at different temperatures obtained for the new pseudomorphic and conventional MODFET's have clearly indicated that contributions from various deep levels present in the new structure are significantly reduced.

  12. Structural modulation of lithium metal-electrolyte interface with three-dimensional metallic interlayer for high-performance lithium metal batteries

    PubMed Central

    Lee, Hongkyung; Song, Jongchan; Kim, Yun-Jung; Park, Jung-Ki; Kim, Hee-Tak

    2016-01-01

    The use of lithium (Li) metal anodes has been reconsidered because of the necessity for a higher energy density in secondary batteries. However, Li metal anodes suffer from ‘dead’ Li formation and surface deactivation which consequently form a porous layer of redundant Li aggregates. In this work, a fibrous metal felt (FMF) as a three-dimensional conductive interlayer was introduced between the separator and the Li metal anode to improve the reversibility of the Li metal anode. The FMF can facilitate charge transfer in the porous layer, rendering it electrochemically more active. In addition, the FMF acted as a robust scaffold to accommodate Li deposits compactly in its interstitial sites. The FMF-integrated Li metal (FMF/Li) electrode operated with a small polarisation even at a current density of 10 mA cm−2, and it exhibited a seven times longer cycle-life than that of an FMF-free Li electrode in a symmetric cell configuration. A Li metal battery (LMB) using the FMF/Li electrode and a LiFePO4 electrode exhibited a two-fold increase in cycling stability compared with that of a bare Li metal electrode, demonstrating the practical effectiveness of this approach for high performance LMBs. PMID:27484160

  13. Structural modulation of lithium metal-electrolyte interface with three-dimensional metallic interlayer for high-performance lithium metal batteries

    NASA Astrophysics Data System (ADS)

    Lee, Hongkyung; Song, Jongchan; Kim, Yun-Jung; Park, Jung-Ki; Kim, Hee-Tak

    2016-08-01

    The use of lithium (Li) metal anodes has been reconsidered because of the necessity for a higher energy density in secondary batteries. However, Li metal anodes suffer from ‘dead’ Li formation and surface deactivation which consequently form a porous layer of redundant Li aggregates. In this work, a fibrous metal felt (FMF) as a three-dimensional conductive interlayer was introduced between the separator and the Li metal anode to improve the reversibility of the Li metal anode. The FMF can facilitate charge transfer in the porous layer, rendering it electrochemically more active. In addition, the FMF acted as a robust scaffold to accommodate Li deposits compactly in its interstitial sites. The FMF-integrated Li metal (FMF/Li) electrode operated with a small polarisation even at a current density of 10 mA cm‑2, and it exhibited a seven times longer cycle-life than that of an FMF-free Li electrode in a symmetric cell configuration. A Li metal battery (LMB) using the FMF/Li electrode and a LiFePO4 electrode exhibited a two-fold increase in cycling stability compared with that of a bare Li metal electrode, demonstrating the practical effectiveness of this approach for high performance LMBs.

  14. Modulation of exogenous selenium in cadmium-induced changes in antioxidative metabolism, cadmium uptake, and photosynthetic performance in the 2 tobacco genotypes differing in cadmium tolerance.

    PubMed

    Liu, Wenxing; Shang, Shenghua; Feng, Xue; Zhang, Guoping; Wu, Feibo

    2015-01-01

    Hydroponic experiments were conducted using cadmium (Cd)-sensitive (cv Guiyan 1) and Cd-tolerant (Yunyan 2) tobacco cultivars to evaluate cultivar differences in response to Cd toxicity in the presence of selenium (Se). The results showed that addition of 3 µM Se in 50 µM Cd solution markedly reduced Cd accumulation in plants, alleviated Cd-induced growth inhibition, and increased nitrogen and chlorophyll contents as well as photosynthetic performance (i.e., net photosynthetic rate, stomatal conductance, and transpiration rate). External Se dramatically depressed Cd-induced O2 (•-) , H2 O2 , and malondialdehyde accumulation, especially in the sensitive cultivar. Selenium significantly elevated Cd-depressed activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione-peroxidase, and glutathione reductase in the both cultivars after 7-d treatments. Meanwhile, Se counteracted Cd-induced alterations in certain nutrient elements; for example, it significantly increased Zn and Ca concentrations and reduced Mg concentration in both cultivars. Furthermore, Se significantly elevated Cd-depressed H(+) -K(+) -adenosine triphosphatase (ATPase), Na(+) -K(+) -ATPase, and Ca(2+) -Mg(2+) -ATPase activities. The beneficial effect of Se under Cd stress may be related mainly to the increased ATPase activity and reduced Cd uptake and reactive oxygen species accumulation, thus reducing the negative consequences of oxidative stress caused by Cd toxicity. PMID:25263007

  15. Spacelab-1 Module

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This photograph shows the Spacelab-1 module and Spacelab access turnel being installed in the cargo bay of orbiter Columbia for the STS-9 mission. The oribiting laboratory, built by the European Space Agency, is capable of supporting many types of scientific research that can best be performed in space. The Spacelab access tunnel, the only major piece of Spacelab hardware made in the U.S., connects the module with the mid-deck level of the orbiter cabin. The first Spacelab mission, Spacelab-1, sponsored jointly and shared equally by NASA and the European Space Agency, was a multidisciplinary mission; that is, investigations were performed in several different fields of scientific research. The overall goal of the mission was to verify Spacelab performance through a variety of scientific experiments. The disciplines represented by these experiments were: astronomy and solar physics, earth observations, space plasma physics, materials sciences, atmospheric physics, and life sciences. International in nature, Spacelab-1 conducted experiments from the United States, Japan, the Netherlands, United Kingdom, Beluga, France, Germany, Italy, and Switzerland. Spacelab-1, was launched from the Kennedy Space Center on November 28, 1983 aboard the orbiter Columbia (STS-9). The Marshall Space Flight Center was responsible for managing the Spacelab missions.

  16. Arbuscular mycorrhizal symbiosis regulates physiology and performance of Digitaria eriantha plants subjected to abiotic stresses by modulating antioxidant and jasmonate levels.

    PubMed

    Pedranzani, H; Rodríguez-Rivera, M; Gutiérrez, M; Porcel, R; Hause, B; Ruiz-Lozano, J M

    2016-02-01

    This study evaluates antioxidant responses and jasmonate regulation in Digitaria eriantha cv. Sudafricana plants inoculated (AM) and non-inoculated (non-AM) with Rhizophagus irregularis and subjected to drought, cold, or salinity. Stomatal conductance, photosynthetic efficiency, biomass production, hydrogen peroxide accumulation, lipid peroxidation, antioxidants enzymes activities, and jasmonate levels were determined. Stomatal conductance and photosynthetic efficiency decreased in AM and non-AM plants under all stress conditions. However, AM plants subjected to drought, salinity, or non-stress conditions showed significantly higher stomatal conductance values. AM plants subjected to drought or non-stress conditions increased their shoot/root biomass ratios, whereas salinity and cold caused a decrease in these ratios. Hydrogen peroxide accumulation, which was high in non-AM plant roots under all treatments, increased significantly in non-AM plant shoots under cold stress and in AM plants under non-stress and drought conditions. Lipid peroxidation increased in the roots of all plants under drought conditions. In shoots, although lipid peroxidation decreased in AM plants under non-stress and cold conditions, it increased under drought and salinity. AM plants consistently showed high catalase (CAT) and ascorbate peroxidase (APX) activity under all treatments. By contrast, the glutathione reductase (GR) and superoxide dismutase (SOD) activity of AM roots was lower than that of non-AM plants and increased in shoots. The endogenous levels of cis-12-oxophytodienoc acid (OPDA), jasmonic acid (JA), and 12-OH-JA showed a significant increase in AM plants as compared to non-AM plants. 11-OH-JA content only increased in AM plants subjected to drought. Results show that D. eriantha is sensitive to drought, salinity, and cold stresses and that inoculation with AM fungi regulates its physiology and performance under such conditions, with antioxidants and jasmonates being involved

  17. Modulation of exogenous glutathione in phytochelatins and photosynthetic performance against cd stress in the two rice genotypes differing in Cd tolerance.

    PubMed

    Cai, Yue; Cao, Fangbin; Cheng, Wangda; Zhang, Guoping; Wu, Feibo

    2011-11-01

    Greenhouse hydroponic experiments were conducted using Cd-sensitive (Xiushui63) and tolerant (Bing97252) rice genotypes to evaluate genotypic differences in response of photosynthesis and phytochelatins to Cd toxicity in the presence of exogenous glutathione (GSH). Plant height, chlorophyll content, net photosynthetic rate (Pn), and biomass decreased in 5 and 50 μM Cd treatments, and Cd-sensitive genotype showed more severe reduction than the tolerant one. Cadmium stress caused decrease in maximal photochemical efficiency of PSII (Fv/Fm) and effective PSII quantum yield [Y(II)] and increase in quantum yield of regulated energy dissipation [Y(NPQ)], with changes in Cd-sensitive genotype being more evident. Cadmium-induced phytochelatins (PCs), GSH, and cysteine accumulation was observed in roots of both genotypes, with markedly higher level in PCs and GSH on day 5 in Bing97252 compared with that measured in Xiushui63. Exogenous GSH significantly alleviated growth inhibition in Xiushui63 under 5 μM Cd and in both genotypes in 50 μM Cd. External GSH significantly increased chlorophyll content, Pn, Fv/Fm, and Y(II) of plants exposed to Cd, but decreased Y(NPQ) and the coefficient of non-photochemical quenching (qN). GSH addition significantly increased root GSH content in plants under Cd exposure (except day 5 of 50 μM Cd) and induced up-regulation in PCs of 5 μM-Cd-treated Bing97252 throughout the 15-day and Xiushui63 of 5-day exposure. The results suggest that genotypic difference in the tolerance to Cd stress was positively linked to the capacity in elevation of GSH and PCs, and that alleviation of Cd toxicity by GSH is related to significant improvement in chlorophyll content, photosynthetic performance, and root GSH levels.

  18. Arbuscular mycorrhizal symbiosis regulates physiology and performance of Digitaria eriantha plants subjected to abiotic stresses by modulating antioxidant and jasmonate levels.

    PubMed

    Pedranzani, H; Rodríguez-Rivera, M; Gutiérrez, M; Porcel, R; Hause, B; Ruiz-Lozano, J M

    2016-02-01

    This study evaluates antioxidant responses and jasmonate regulation in Digitaria eriantha cv. Sudafricana plants inoculated (AM) and non-inoculated (non-AM) with Rhizophagus irregularis and subjected to drought, cold, or salinity. Stomatal conductance, photosynthetic efficiency, biomass production, hydrogen peroxide accumulation, lipid peroxidation, antioxidants enzymes activities, and jasmonate levels were determined. Stomatal conductance and photosynthetic efficiency decreased in AM and non-AM plants under all stress conditions. However, AM plants subjected to drought, salinity, or non-stress conditions showed significantly higher stomatal conductance values. AM plants subjected to drought or non-stress conditions increased their shoot/root biomass ratios, whereas salinity and cold caused a decrease in these ratios. Hydrogen peroxide accumulation, which was high in non-AM plant roots under all treatments, increased significantly in non-AM plant shoots under cold stress and in AM plants under non-stress and drought conditions. Lipid peroxidation increased in the roots of all plants under drought conditions. In shoots, although lipid peroxidation decreased in AM plants under non-stress and cold conditions, it increased under drought and salinity. AM plants consistently showed high catalase (CAT) and ascorbate peroxidase (APX) activity under all treatments. By contrast, the glutathione reductase (GR) and superoxide dismutase (SOD) activity of AM roots was lower than that of non-AM plants and increased in shoots. The endogenous levels of cis-12-oxophytodienoc acid (OPDA), jasmonic acid (JA), and 12-OH-JA showed a significant increase in AM plants as compared to non-AM plants. 11-OH-JA content only increased in AM plants subjected to drought. Results show that D. eriantha is sensitive to drought, salinity, and cold stresses and that inoculation with AM fungi regulates its physiology and performance under such conditions, with antioxidants and jasmonates being involved

  19. Receiver Gain Modulation Circuit

    NASA Technical Reports Server (NTRS)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    modulating the receiver gain using an external signal. Without the RGMC, samples of calibrated references from radiometers form an ensemble data set of the natural occurring fluctuations within a receiver. By driving the gain of an otherwise stable receiver with an external signal, the conceptual framework and generalization of the mathematics of EDA can be tested. A series of measurements was conducted to evaluate and characterize the performance of the RGMC. Test signals stepped the RGMC across its dynamic range of performance using a radiometer that sampled four noise references; analysis indicates that the RGMC successfully modulated the receiver gain with an external signal. Calibration algorithms applied to four noise references demonstrate the RGMC produced ensemble data sets of the external signal.

  20. Optical modulators with 2D layered materials

    NASA Astrophysics Data System (ADS)

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  1. Ballasted photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt

    2011-11-29

    A photovoltaic (PV) module assembly including a PV module and a ballast tray. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes an arm. The ballast tray is adapted for containing ballast and is removably associated with the PV module in a ballasting state where the tray is vertically under the PV laminate and vertically over the arm to impede overt displacement of the PV module. The PV module assembly can be installed to a flat commercial rooftop, with the PV module and the ballast tray both resting upon the rooftop. In some embodiments, the ballasting state includes corresponding surfaces of the arm and the tray being spaced from one another under normal (low or no wind) conditions, such that the frame is not continuously subjected to a weight of the tray.

  2. Plug cluster module demonstration

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.

    1978-01-01

    The low pressure, film cooled rocket engine design concept developed during two previous ALRC programs was re-evaluated for application as a module for a plug cluster engine capable of performing space shuttle OTV missions. The nominal engine mixture ratio was 5.5 and the engine life requirements were 1200 thermal cycles and 10 hours total operating life. The program consisted of pretest analysis; engine tests, performed using residual components; and posttest analysis. The pretest analysis indicated that operation of the operation of the film cooled engine at O/F = 5.5 was feasible. During the engine tests, steady state wall temperature and performance measurement were obtained over a range of film cooling flow rates, and the durability of the engine was demonstrated by firing the test engine 1220 times at a nominal performance ranging from 430 - 432 seconds. The performance of the test engine was limited by film coolant sleeve damage which had occurred during previous testing. The post-test analyses indicated that the nominal performance level can be increased to 436 seconds.

  3. Module flammability research

    NASA Technical Reports Server (NTRS)

    Sugimura, R. S.; Otth, D. H.

    1985-01-01

    New materials were developed which show promise of fabricating modules that can pass the Underwriter Laboratories Class A burning brand test for fire ratable solar cell modules. It is concluded that fire resistant module design require special high temperature materials and constructions to achieve Class B and Class A ratings. Also, synergisms exist between back surface materials and module configuration.

  4. Module utilization committee

    NASA Technical Reports Server (NTRS)

    Volkmer, K.; Praver, G.

    1984-01-01

    Photovoltaic collector modules were declared surplus to the needs of the U.S. Dept. of Energy. The Module Utilization Committee was formed to make appropriate disposition of the surplus modules on a national basis and to act as a broker for requests for these modules originating outside of the National Photovoltaics Program.

  5. The Knife Machine. Module 15.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on the knife machine, one in a series dealing with industrial sewing machines, their attachments, and operation, covers one topic: performing special operations on the knife machine (a single needle or multi-needle machine which sews and cuts at the same time). These components are provided: an introduction, directions, an objective,…

  6. Clothing and Textile Student Modules.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    Forty-seven performance-based instructional modules on six major topics are provided for the home economics content area of clothing and textiles. The six topics are (1) planning basics (psychological, physical, social, and behavioral aspects of clothing; elements of design; principles of design; and style and fashion in clothing), (2) buyership…

  7. Shopping. An Adult Competency Education Learning Module.

    ERIC Educational Resources Information Center

    Wallace, Virginia

    This instructional unit on shopping is one of six Adult Competency Education Learning Modules designed for use in a program of competency-based instruction for students with reading levels of 4.0-7.5. It is self-contained and designed for immediate classroom use. Each module is a complete instructional package, including Adult Performance Level…

  8. Transparent superstrate terrestrial solar cell module

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The design, development, fabrication, and testing of the transparent solar cell module were examined. Cell performance and material process characteristics were determined by extensive tests and design modifications were made prior to preproduction fabrication. These tests included three cell submodules and two full size engineering modules. Along with hardware and test activity, engineering documentation was prepared and submitted.

  9. Teacher Aide Individually Prescribed Instructional Modules.

    ERIC Educational Resources Information Center

    Livingston Univ., AL. Coll. of Education.

    This document contains 59 individually prescribed instructional modules for use in teacher aide education programs. Each module has six sections: 1) Behavioral objectives, 2) purpose, 3) performance criteria, 4) experiences, 5) resources, and 6) taxonomy. The subjects covered include the use of instructional equipment such as language master,…

  10. Career Education for Adults: Consumer Economics Module.

    ERIC Educational Resources Information Center

    Auburn Univ., AL. Dept. of Vocational and Adult Education.

    An outgrowth of State-sponsored institutes conducted by Auburn University, Alabama, to produce career education teaching modules for adults, the consumer economics module is one of five field-tested curriculum guides adopted from findings of the nationally oriented Adult Performance Level Study conducted at the University of Texas. The primary…

  11. Modulational effects in accelerators

    SciTech Connect

    Satogata, T.

    1997-12-01

    We discuss effects of field modulations in accelerators, specifically those that can be used for operational beam diagnostics and beam halo control. In transverse beam dynamics, combined effects of nonlinear resonances and tune modulations influence diffusion rates with applied tune modulation has been demonstrated. In the longitudinal domain, applied RF phase and voltage modulations provide mechanisms for parasitic halo transport, useful in slow crystal extraction. Experimental experiences with transverse tune and RF modulations are also discussed.

  12. Almond brush module cutter

    SciTech Connect

    Zohns, M.A.; Jenkins, B.M.; Mehlschau, J.J.; Morrison, D.

    1983-06-01

    This paper addresses the design, construction, and evaluation of an almond brush module cutter. The module cutter is one link in a system which processes tree prunings for fuel and fiber. This system includes a modified cotton module builder, a module mover, the cutter, and a tub grinder. An economic analysis of the cutter is presented along with the problems involved in cutting brush modules.

  13. Optical properties of KD*P modulators

    NASA Technical Reports Server (NTRS)

    West, E. A.; Bhatia, S. S.

    1990-01-01

    Longitudinal KD*P modulators are used in ground-based solar magnetographs to eliminate seeing effects. Although the modulators can be used as variable retarders, the optical properties when zero voltage is applied influences the performance on instruments requiring very accurate polarization measurements. Measurements at the Marshall Space Flight Center are discussed in terms of the optical properties of KD*P modulators when zero voltage is applied. The measurements can be used to predict the modulation characteristics of the devices and to determine the polarization accuracy that can be expected from the vector magnetograph.

  14. Residential photovoltaic module and array requirements study

    NASA Technical Reports Server (NTRS)

    Nearhoof, S. L.; Oster, J. R.

    1979-01-01

    Design requirements for photovoltaic modules and arrays used in residential applications were identified. Building codes and referenced standards were reviewed for their applicability to residential photovoltaic array installations. Four installation types were identified - integral (replaces roofing), direct (mounted on top of roofing), stand-off (mounted away from roofing), and rack (for flat or low slope roofs, or ground mounted). Installation costs were developed for these mounting types as a function of panel/module size. Studies were performed to identify optimum module shapes and sizes and operating voltage cost drivers. It is concluded that there are no perceived major obstacles to the use of photovoltaic modules in residential arrays. However, there is no applicable building code category for residential photovoltaic modules and arrays and additional work with standards writing organizations is needed to develop residential module and array requirements.

  15. Photovoltaic module bypass diode encapsulation

    NASA Technical Reports Server (NTRS)

    Shepard, N. J., Jr.

    1983-01-01

    The design and processing techniques necessary to incorporate bypass diodes within the module encapsulant are presented. The Semicon PN junction diode cells were selected. Diode junction to heat spreader thermal resistance measurements, performed on a variety of mounted diode chip types and sizes, have yielded values which are consistently below 1 deg C per watt, but show some instability when thermally cycled over the temperature range from -40 to 150 deg C. Three representative experimental modules, each incorporating integral bypass diode/heat spreader assemblies of various sizes, were designed. Thermal testing of these modules enabled the formulation of a recommended heat spreader plate sizing relationship. The production cost of three encapsulated bypass diode/heat spreader assemblies were compared with similarly rated externally mounted packaged diodes. It is concluded that, when proper designed and installed, these bypass diode devices will improve the overall reliability of a terrestrial array over a 20 year design lifetime.

  16. The assess facility descriptor module

    SciTech Connect

    Jordan, S.E.; Winblad, A.; Key, B.; Walker, S.; Renis, T.; Saleh, R.

    1989-01-01

    The Facility Descriptor (Facility) module is part of the Analytic System and Software for Evaluating Safeguards and Security (ASSESS). Facility is the foundational software application in the ASSESS system for modelling a nuclear facility's safeguards and security system to determine the effectiveness against theft of special nuclear material. The Facility module provides the tools for an analyst to define a complete description of a facility's physical protection system which can then be used by other ASSESS software modules to determine vulnerability to a spectrum of insider and outsider threats. The analyst can enter a comprehensive description of the protection system layout including all secured areas, target locations, and detailed safeguards specifications. An extensive safeguard component catalog provides the reference data for calculating delay and detection performance. Multiple target locations within the same physical area may be specified, and the facility may be defined for two different operational states such as dayshift and nightshift. 6 refs., 5 figs.

  17. Amplitude and phase modulation with waveguide optics

    SciTech Connect

    Burkhart, S.C.; Wilcox, R.B.; Browning, D.; Penko, F.A.

    1996-12-17

    We have developed amplitude and phase modulation systems for glass lasers using integrated electro-optic modulators and solid state high- speed electronics. The present and future generation of lasers for Inertial Confinement Fusion require laser beams with complex temporal and phase shaping to compensate for laser gain saturation, mitigate parametric processes such as transverse stimulated Brillouin scattering in optics, and to provide specialized drive to the fusion targets. These functions can be performed using bulk optoelectronic modulators, however using high-speed electronics to drive low voltage integrated optical modulators has many practical advantages. In particular, we utilize microwave GaAs transistors to perform precision, 250 ps resolution temporal shaping. Optical bandwidth is generated using a microwave oscillator at 3 GHz amplified by a solid state amplifier. This drives an integrated electrooptic modulator to achieve laser bandwidths exceeding 30 GHz.

  18. Commerical module test program

    NASA Technical Reports Server (NTRS)

    Smokier, M. I.

    1986-01-01

    The results are presented for a program of qualification testing of commercial crystalline silicon modules from nine manufacturers in five countries. The outcome demonstrated the effective role of the Block 5 Qualification Tests in the development of reliable modules.

  19. Integrated spatial light modulator

    NASA Astrophysics Data System (ADS)

    Yu, Dong X.; Storti, George M.; Wrigley, Charles Y.

    1992-08-01

    We described here an integrated spatial light modulator (SLM) employing Quantex electron trapping (ET) materials. The light modulation is accomplished by emission of ET material, upon incident coherent infrared light, where a pattern is written to by previous visible light excitation. The ET based spatial light modulators offer unique advantages over other SLM devices, such as capability of converting incoherent input to coherent light output and of integrating the modulator, the photodetector, and the memory into a single, rugged unit.

  20. Module optical analyzer: Identification of defects on the production line

    NASA Astrophysics Data System (ADS)

    Herrero, Rebeca; Askins, Stephen; Antón, Ignacio; Sala, Gabriel; Araki, Kenji; Nagai, Hirokazu

    2014-09-01

    The usefulness of the module optical analyzer when identifying module defects on production line is presented in this paper. Two different case studies performed with two different kind of CPV modules are presented to show the use of MOA both in IES-UPM and Daido Steel facilities.