WorldWideScience

Sample records for standard candle flickers

  1. When a Standard Candle Flickers

    DEFF Research Database (Denmark)

    Wilson-Hodge, Colleen A; Cherry, Michael L; Case, Gary L

    2011-01-01

    The Crab Nebula is the only hard X-ray source in the sky that is both bright enough and steady enough to be easily used as a standard candle. As a result, it has been used as a normalization standard by most X-ray/gamma-ray telescopes. Although small-scale variations in the nebula are well known......, since the start of science operations of the Fermi Gamma-ray Burst Monitor (GBM) in 2008 August, a ~ 7% (70 mCrab) decline has been observed in the overall Crab Nebula flux in the 15-50 keV band, measured with the Earth occultation technique. This decline is independently confirmed in the ~ 15-50 ke......-100 keV band with GBM, Swift /BAT, and INTEGRAL /IBIS. The pulsed flux measured with RXTE /PCA since 1999 is consistent with the pulsar spin-down, indicating that the observed changes are nebular. Correlated variations in the Crab Nebula flux on a ~ 3 year timescale are also seen independently...

  2. When A Standard Candle Flickers

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Cherry, Michael L.; Case, Gary L.; Baumgartner, Wayne H.; Beklen Elif; Bhat, P. Narayana; Briggs, Michael S.; Camero-Arranz, Ascension; Chaplin, Vandiver; Connaughton, Valerie; hide

    2011-01-01

    The Crab Nebula is the only hard X-ray source in the sky that is both bright enough and steady enough to be easily used as a standard candle. As a result, it has been used as a normalization standard by most X-ray/gamma ray telescopes. Although small-scale variations in the nebula are well-known, since the start of science operations of the Fermi Gamma-ray Burst Monitor (GBM) in August 2008 a 7% (70 mcrab) decline has been observed in the overall Crab Nebula flux in the 15-50 keV band, measured with the Earth occultation technique. This decline is independently confirmed in the 15-50 keV band with three other instruments: the Swift Burst Alert Telescope (Swift/BAT), the Rossi X-ray Timing Explorer Proportional Counter Array (RXTE/PCA), and the INTErnational Gamma-Ray Astrophysics Laboratory Imager on Board INTEGRAL (IBIS). A similar decline is also observed in the 3 - 15 keV data from the RXTE/PCA and in the 50 - 100 keV band with GBM, Swift/BAT, and INTEGRAL/IBIS. The change in the pulsed flux measured with RXTE/PCA since 1999 is consistent with the pulsar spin-down, indicating that the observed changes are nebular. Correlated variations in the Crab Nebula flux on a 3 year timescale are also seen independently with the PCA, BAT, and IBIS from 2005 to 2008, with a flux minimum in April 2007. As of August 2010, the current flux has declined below the 2007 minimum.

  3. Difficulties in Using GRBs as Standard Candles

    Science.gov (United States)

    Goldstein, Adam

    2012-01-01

    Gamma-Ray Bursts have been detected uniformly all over the observable universe, ranging in comoving distance from a few hundred Mpc to a few thousand Mpc, representing the farthest observable objects in the universe. This large distance coverage is highly attractive to those who study cosmology and the history of the early universe since there are no other observed objects that represent such a deep and comprehensive probe of the history of the universe. For this reason, there have been extensive studies into the possibility of using GRBs as standard candles much like Type Ia Supernovae, even though little is known about the physical mechanism that produces the observed burst of gamma-rays. We discuss the attempts at defining GRBs as standard candles, such as the search for a robust luminosity indicator, pseudo-redshift predictions, the complications that emission collimation introduces into the estimation of the rest-frame energetics, and the difficulty introduced by the widely varying observed properties of GRBs. These topics will be examined with supporting data and analyses from both Fermi and Swift observations. Problems with current studies using GRBs as standard candles will be noted as well as potential paths forward to solve these problems.

  4. The Gaia Red Clump as standard candle

    Science.gov (United States)

    Ruiz-Dern, L.; Babusiaux, C.; Danielski, C.; Arenou, F.; Turon, C.; Lallement, R.

    2017-12-01

    Gaia has already provided new high precision parallaxes for two million objects, allowing to recalibrate standard candles. Red Clump stars are known to be good standard candles because of their small dependency of their luminosity on their stellar composition, colour and age. We developed methods to derive some of the main physical parameters to characterise the Red Clump as standard candle. We provide fully empirical calibrations by using visual to infrared photometry, the most up-to-date 3D extinction map, and spectroscopic atmosphere parameters. We derived new calibrations for 16 Colour-(\\gk) and Effective Temperature-(\\gk) relations and a new calibration of the RC absolute magnitude on the Gaia G and 2MASS \\ks bands. These calibrations are used afterwards to estimate the G-band interstellar extinction coefficient k_{G}. By combining of all these relations we implemented a method to determine effective temperatures and interstellar extinctions (A_0), which we will use in particular to derive asteroseismic parameters which can be directly compared with Gaia's results.

  5. Comparison of cosmological models using standard rulers and candles

    OpenAIRE

    Li, Xiaolei; Cao, Shuo; Zheng, Xiaogang; Li, Song; Biesiada, Marek

    2015-01-01

    In this paper, we used standard rulers and standard candles (separately and jointly) to explore five popular dark energy models under assumption of spatial flatness of the Universe. As standard rulers, we used a data set comprising 118 galactic-scale strong lensing systems (individual standard rulers if properly calibrated for the mass density profile) combined with BAO diagnostics (statistical standard ruler). Supernovae Ia served asstandard candles. Unlike in the most of previous statistica...

  6. Flicker

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-03-01

    Solid-state lighting program technology fact sheet that discusses flicker metrics, contributing factors, and consequences in addition to comparing the flicker attributes of a sample of conventional and LED sources.

  7. Investigating the Effect of Cosmic Opacity on Standard Candles

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J.; Yu, H.; Wang, F. Y., E-mail: fayinwang@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2017-02-10

    Standard candles can probe the evolution of dark energy over a large redshift range. But the cosmic opacity can degrade the quality of standard candles. In this paper, we use the latest observations, including Type Ia supernovae (SNe Ia) from the “joint light-curve analysis” sample and Hubble parameters, to probe the opacity of the universe. A joint fitting of the SNe Ia light-curve parameters, cosmological parameters, and opacity is used in order to avoid the cosmological dependence of SNe Ia luminosity distances. The latest gamma-ray bursts are used in order to explore the cosmic opacity at high redshifts. The cosmic reionization process is considered at high redshifts. We find that the sample supports an almost transparent universe for flat ΛCDM and XCDM models. Meanwhile, free electrons deplete photons from standard candles through (inverse) Compton scattering, which is known as an important component of opacity. This Compton dimming may play an important role in future supernova surveys. From analysis, we find that about a few per cent of the cosmic opacity is caused by Compton dimming in the two models, which can be corrected.

  8. Discerning dark energy models with high redshift standard candles

    Science.gov (United States)

    Andersen, P.; Hjorth, J.

    2017-12-01

    Following the success of type Ia supernovae in constraining cosmologies at lower redshift (z ≲ 2), effort has been spent determining if a similarly useful standardizable candle can be found at higher redshift. In this work, we determine the largest possible magnitude discrepancy between a constant dark energy ΛCDM cosmology and a cosmology in which the equation of state w(z) of dark energy is a function of redshift for high redshift standard candles (z ≳ 2). We discuss a number of popular parametrizations of w(z) with two free parameters, wzCDM cosmologies, including the Chevallier-Polarski-Linder and generalization thereof, nCPL, as well as the Jassal-Bagla-Padmanabhan parametrization. For each of these parametrizations, we calculate and find the extrema of Δμ, the difference between the distance modulus of a wzCDM cosmology and a fiducial ΛCDM cosmology as a function of redshift, given 68 per cent likelihood constraints on the parameters P = (Ωm, 0, w0, wa). The parameters are constrained using cosmic microwave background, baryon acoustic oscillations and type Ia supernovae data using CosmoMC. We find that none of the tested cosmologies can deviate more than 0.05 mag from the fiducial ΛCDM cosmology at high redshift, implying that high redshift standard candles will not aid in discerning between the wzCDM cosmology and the fiducial ΛCDM cosmology. Conversely, this implies that if high redshift standard candles are found to be in disagreement with ΛCDM at high redshift, then this is a problem not only for ΛCDM but for the entire family of wzCDM cosmologies.

  9. THE STANDARDIZED CANDLE METHOD FOR TYPE II PLATEAU SUPERNOVAE

    International Nuclear Information System (INIS)

    Olivares E, Felipe; Hamuy, Mario; Pignata, Giuliano; Maza, Jose; Bersten, Melina; Phillips, Mark M.; Morrel, Nidia I.; Suntzeff, Nicholas B.; Filippenko, Alexei V.; Kirshner, Robert P.; Matheson, Thomas

    2010-01-01

    In this paper, we study the 'standardized candle method' using a sample of 37 nearby (redshift z V ) = 0.2 mag. The correlation between plateau luminosity and expansion velocity previously reported in the literature is recovered. Using this relation and assuming a standard reddening law (R V = 3.1), we obtain Hubble diagrams (HDs) in the BVI bands with dispersions of ∼0.4 mag. Allowing R V to vary and minimizing the spread in the HDs, we obtain a dispersion range of 0.25-0.30 mag, which implies that these objects can deliver relative distances with precisions of 12%-14%. The resulting best-fit value of R V is 1.4 ± 0.1.

  10. How Beatrice Tinsley Destroyed Sandage's Quest for a Standard Candle

    Science.gov (United States)

    Mitton, Simon

    2014-01-01

    The goal of cosmology and most extragalactic optical astronomy during the heroic period spanning the half century from Hubble to Sandage (1920s - 1970s) was a search for two numbers, the Hubble constant and the deceleration parameter. Standard candles were needed to establish the measure of the universe. In 1968, Beatrice Tinsley, then a postdoctoral fellow in the astronomy department of the University of Texas at Austin showed that the great enterprise at Palomar of calibrating the galaxies was in need of major revision. At the 132nd AAS Meeting (June 1970, Boulder, Colorado) she presented a paper on galactic evolution on the magnitude-redshift relation. In her Abstract she boldly wrote: "My present conclusion is opposite to that reached by most cosmologists." In fact her claims caused great consternation among cosmologists. In 1972 she published eight papers on the evolution of galaxies, and the effects of that evolution for observational cosmology and the origin of structure.

  11. Validation of the Standard Method for Assessing Flicker From Wind Turbines

    DEFF Research Database (Denmark)

    Barahona Garzon, Braulio; Sørensen, Poul Ejnar; Christensen, L.

    2011-01-01

    This paper studies the validity of the standard method in IEC 61400-21 for assessing the flicker emission from multiple wind turbines. The standard method is based on testing a single wind turbine and then using the results of this test to assess the flicker emission from a number of wind turbines...... the flicker emission at the collection line; this assessment is then compared to the actual measurements in order to study the accuracy of the estimation. It was observed in both wind farms, that the assessment based on the standard method is statistically conservative compared to the measurements. The reason...... for this is the statistical characteristics of flicker emission....

  12. When a Standard Candle Flickers: Crab Nebula Variations in Hard X-rays

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    The Crab Nebula was surprisingly variable from 2001-2010, with less variability before 2001 and since mid-2010. We presented evidence for spectral softening from RXTE, Swift/BAT, and Fermi GBM during the mid-2008-2010 flux decline. We will miss RXTE, but will continue our monitoring program using Fermi/GBM, MAXI, and Swift/BAT.

  13. Red clump stars and Gaia: calibration of the standard candle using a hierarchical probabilistic model

    Science.gov (United States)

    Hawkins, Keith; Leistedt, Boris; Bovy, Jo; Hogg, David W.

    2017-10-01

    Distances to individual stars in our own Galaxy are critical in order to piece together the nature of its velocity and spatial structure. Core helium burning red clump (RC) stars have similar luminosities, are abundant throughout the Galaxy and thus constitute good standard candles. We build a hierarchical probabilistic model to quantify the quality of RC stars as standard candles using parallax measurements from the first Gaia data release. A unique aspect of our methodology is to fully account for (and marginalize over) parallax, photometry and dust correction uncertainties, which lead to more robust results than standard approaches. We determine the absolute magnitude and intrinsic dispersion of the RC in 2MASS bands J, H, Ks, Gaia G band and WISE bands W1, W2, W3 and W4. We find that the absolute magnitude of the RC is -1.61 ± 0.01 (in Ks), +0.44 ± 0.01 (in G), -0.93 ± 0.01 (in J), -1.46 ± 0.01 (in H), -1.68 ± 0.02 (in W1), -1.69 ± 0.02 (in W2), -1.67 ± 0.02 (in W3) and -1.76 ± 0.01 mag (in W4). The mean intrinsic dispersion is ˜0.17 ± 0.03 mag across all bands (yielding a typical distance precision of ˜8 per cent). Thus RC stars are reliable and precise standard candles. In addition, we have also re-calibrated the zero-point of the absolute magnitude of the RC in each band, which provides a benchmark for future studies to estimate distances to RC stars. Finally, the parallax error shrinkage in the hierarchical model outlined in this work can be used to obtain more precise parallaxes than Gaia for the most distant RC stars across the Galaxy.

  14. Standard test method for determining atmospheric chloride deposition rate by wet candle method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers a wet candle device and its use in measuring atmospheric chloride deposition (amount of chloride salts deposited from the atmosphere on a given area per unit time). 1.2 Data on atmospheric chloride deposition can be useful in classifying the corrosivity of a specific area, such as an atmospheric test site. Caution must be exercised, however, to take into consideration the season because airborne chlorides vary widely between seasons. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  15. $\\Zeta$-boson as "the standard candle" for high precision W-boson physics at LHC

    CERN Document Server

    Krasny, M W; Placzek, W; Siodmok, A

    2007-01-01

    In this paper we propose a strategy for measuring the inclusive W-boson production processes at LHC. This strategy exploits simultaneously the unique flexibility of the LHC collider in running variable beam particle species at variable beam energies, and the configuration flexibility of the LHC detectors. We propose their concrete settings for a precision measurement of the Standard Model parameters. These settings optimise the use of the Z boson and Drell-Yan pair production processes as ``the standard reference candles''. The presented strategy allows to factorise and to directly measure those of the QCD effects which affect differently the W and Z production processes. It reduces to a level of 10^{-4} the impact of uncertainties in the partonic distribution functions (PDFs) and in the transverse momentum of the quarks on the measurement precision. Last but not the least, it reduces by a factor of 10 an impact of systematic measurement errors, such as the energy scale and the measurement resolution, on the ...

  16. From a Better Understanding of GRB Prompt Emission to a New Type of Standard Candles?

    Science.gov (United States)

    Guiriec, Sylvain

    2016-07-01

    Recent results revealed the simultaneous existence of multiple components in the prompt emission of gamma-ray bursts (GRBs) leading to a unified spectro-temporal model for the broadband spectrum from the optical regime up to higher gamma rays. Unexpectedly, we discovered a relation intrinsic to one specific component of this model: its luminosity is strongly and tightly correlated to its spectral break energy. This new luminosity-hardness relation has the same index for all GRBs when fitted to a power law. In addition, this relation seems to have the same normalization for all GRBs; therefore, this is a promising and physically motivated tool that may establish GRBs as cosmological standard candles. During this presentation, I will introduce this new relation, which might eventually be used to (i) estimate GRB distances, (ii) to support searches for gravitational waves and cosmic high-energy neutrinos, and (iii) constrain the cosmological parameters. I will give a few examples of GRB redshift estimates using this relation and I will show why this new result cannot solely be explain by instrumental selection effects and/or measurement/analysis biases.

  17. Standard rulers, candles, and clocks from the low-redshift universe.

    Science.gov (United States)

    Heavens, Alan; Jimenez, Raul; Verde, Licia

    2014-12-12

    We measure the length of the baryon acoustic oscillation (BAO) feature, and the expansion rate of the recent Universe, from low-redshift data only, almost model independently. We make only the following minimal assumptions: homogeneity and isotropy, a metric theory of gravity, a smooth expansion history, and the existence of standard candles (supernovæ) and a standard BAO ruler. The rest is determined by the data, which are compilations of recent BAO and type IA supernova results. Making only these assumptions, we find for the first time that the standard ruler has a length of 103.9±2.3h⁻¹ Mpc. The value is a measurement, in contrast to the model-dependent theoretical prediction determined with model parameters set by Planck data (99.3±2.1h⁻¹ Mpc). The latter assumes the cold dark matter model with a cosmological constant, and that the ruler is the sound horizon at radiation drag. Adding passive galaxies as standard clocks or a local Hubble constant measurement allows the absolute BAO scale to be determined (142.8±3.7 Mpc), and in the former case the additional information makes the BAO length determination more precise (101.9±1.9h⁻¹ Mpc). The inverse curvature radius of the Universe is weakly constrained and consistent with zero, independently of the gravity model, provided it is metric. We find the effective number of relativistic species to be N(eff)=3.53±0.32, independent of late-time dark energy or gravity physics.

  18. Measuring the Hubble constant with Type Ia supernovae as near-infrared standard candles

    Science.gov (United States)

    Dhawan, Suhail; Jha, Saurabh W.; Leibundgut, Bruno

    2018-01-01

    The most precise local measurements of H0 rely on observations of Type Ia supernovae (SNe Ia) coupled with Cepheid distances to SN Ia host galaxies. Recent results have shown tension comparing H0 to the value inferred from CMB observations assuming ΛCDM, making it important to check for potential systematic uncertainties in either approach. To date, precise local H0 measurements have used SN Ia distances based on optical photometry, with corrections for light curve shape and colour. Here, we analyse SNe Ia as standard candles in the near-infrared (NIR), where luminosity variations in the supernovae and extinction by dust are both reduced relative to the optical. From a combined fit to 9 nearby calibrator SNe with host Cepheid distances from Riess et al. (2016) and 27 SNe in the Hubble flow, we estimate the absolute peak J magnitude MJ = -18.524 ± 0.041 mag and H0 = 72.8 ± 1.6 (statistical) ±2.7 (systematic) km s-1 Mpc-1. The 2.2% statistical uncertainty demonstrates that the NIR provides a compelling avenue to measuring SN Ia distances, and for our sample the intrinsic (unmodeled) peak J magnitude scatter is just 0.10 mag, even without light curve shape or colour corrections. Our results do not vary significantly with different sample selection criteria, though photometric calibration in the NIR may be a dominant systematic uncertainty. Our findings suggest that tension in the competing H0 distance ladders is likely not a result of supernova systematics that could be expected to vary between optical and NIR wavelengths, like dust extinction. We anticipate further improvements in H0 with a larger calibrator sample of SNe Ia with Cepheid distances, more Hubble flow SNe Ia with NIR light curves, and better use of the full NIR photometric data set beyond simply the peak J-band magnitude.

  19. [Progression of flicker perimetry in clinical application].

    Science.gov (United States)

    Yu, Fengqi; Wang, Dabo

    2014-05-01

    Flicker perimetry measures the function of retina by stimulating it using flickering light. It has three test modes:contrast modulation flicker, critical flicker fusion frequency and luminance pedestal flicker. These 3 modes have their own characteristics. Flicker perimetry shows a higher sensitivity than white-white standard automated perimetry in early diagnosis of glaucoma. It also has advantages in the diagnosis for age-related macular degeneration, diabetic retinopathy and other retinal diseases. With further understanding of the flicker perimetry, its clinical application will gradually expand. In this paper, the basic principle and clinical application are reviewed.

  20. A Unified Model for GRB Prompt Emission from Optical to Gamma-Rays; Exploring GRBs as Standard Candles

    Science.gov (United States)

    Guiriec, S.; Kouveliotou, C.; Hartmann, D. H.; Granot, J.; Asano, K.; Meszaros, P.; Gill, R.; Gehrels, N.; McEnery, J.

    2016-01-01

    The origin of prompt emission from gamma-ray bursts (GRBs) remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the broadband GRB spectrum prompted the hypothesis of different emission mechanisms for the low- and high-energy radiations. We demonstrate that our multi-component model for GRB -ray prompt emission provides an excellent fit to GRB 110205A from optical to gamma-ray energies. Our results show that the optical and highest gamma-ray emissions have the same spatial and spectral origin, which is different from the bulk of the X- and softest gamma-ray radiation. Finally, our accurate redshift estimate for GRB 110205A demonstrates promise for using GRBs as cosmological standard candles.

  1. A UNIFIED MODEL FOR GRB PROMPT EMISSION FROM OPTICAL TO γ -RAYS; EXPLORING GRBs AS STANDARD CANDLES

    Energy Technology Data Exchange (ETDEWEB)

    Guiriec, S.; Kouveliotou, C. [Department of Physics, The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); Hartmann, D. H. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Granot, J.; Gill, R. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raanana 4353701 (Israel); Asano, K. [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Mészáros, P. [Department of Astronomy and Astrophysics and Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Gehrels, N.; McEnery, J., E-mail: sylvain.guiriec@nasa.gov [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-11-01

    The origin of prompt emission from gamma-ray bursts (GRBs) remains to be an open question. Correlated prompt optical and γ -ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the broadband GRB spectrum prompted the hypothesis of different emission mechanisms for the low- and high-energy radiations. We demonstrate that our multi-component model for GRB γ -ray prompt emission provides an excellent fit to GRB 110205A from optical to γ -ray energies. Our results show that the optical and highest γ -ray emissions have the same spatial and spectral origin, which is different from the bulk of the X- and softest γ -ray radiation. Finally, our accurate redshift estimate for GRB 110205A demonstrates promise for using GRBs as cosmological standard candles.

  2. New mass limit for white dwarfs: super-Chandrasekhar type ia supernova as a new standard candle.

    Science.gov (United States)

    Das, Upasana; Mukhopadhyay, Banibrata

    2013-02-15

    Type Ia supernovae, sparked off by exploding white dwarfs of mass close to the Chandrasekhar limit, play the key role in understanding the expansion rate of the Universe. However, recent observations of several peculiar type Ia supernovae argue for its progenitor mass to be significantly super-Chandrasekhar. We show that strongly magnetized white dwarfs not only can violate the Chandrasekhar mass limit significantly, but exhibit a different mass limit. We establish from a foundational level that the generic mass limit of white dwarfs is 2.58 solar mass. This explains the origin of overluminous peculiar type Ia supernovae. Our finding further argues for a possible second standard candle, which has many far reaching implications, including a possible reconsideration of the expansion history of the Universe.

  3. A Unified Model for GRB Prompt Emission from Optical to Gamma-Rays: Exploring GRBs as Standard Candles

    Science.gov (United States)

    Guiriec, Sylvain

    2018-01-01

    The Band function traditionally used for Gamma Ray Bursts (GRB) often fails to fit their prompt emission spectra. Our new model composed of three separate components provides an excellent description of the time-resolved prompt emission: a thermal-like and two non-thermal components. For the first time, analysis of GRBs with correlated optical and gamma-ray prompt emission show that our new model describes very accurately the whole broadband spectrum from the optical regime to higher energy gamma rays. In addition, this new model enables anew luminosity/hardness relation intrinsic to one of the non-thermal components showing that GRBs may be standard candles. If statistically confirmed, this relation will be used to (i) constrain the mechanisms powering GRB jets, (ii) estimate GRB distances, (iii) probe the early Universe, and (iv) constrain the cosmological parameters. I will present this new unified model using analysis of GRBs detected with various observatories and instruments such as Fermi, CGRO/BATSE and the combination of the three instruments on board Swift and Suzaku/WAM. I will discuss here the striking similarities of GRB spectral shapes, whose components inform on the nature of the prompt emission, as well as the possible universality of the proposed luminosity/hardness relation in the context of our new model.

  4. SN 2016jhj at redshift 0.34: extending the Type II supernova Hubble diagram using the standard candle method

    Science.gov (United States)

    de Jaeger, T.; Galbany, L.; Filippenko, A. V.; González-Gaitán, S.; Yasuda, N.; Maeda, K.; Tanaka, M.; Morokuma, T.; Moriya, T. J.; Tominaga, N.; Nomoto, K.; Komiyama, Y.; Anderson, J. P.; Brink, T. G.; Carlberg, R. G.; Folatelli, G.; Hamuy, M.; Pignata, G.; Zheng, W.

    2017-12-01

    Although Type Ia supernova cosmology has now reached a mature state, it is important to develop as many independent methods as possible to understand the true nature of dark energy. Recent studies have shown that Type II supernovae (SNe II) offer such a path and could be used as alternative distance indicators. However, the majority of these studies were unable to extend the Hubble diagram above redshift z = 0.3 because of observational limitations. Here, we show that we are now ready to move beyond low redshifts and attempt high-redshift (z ≳ 0.3) SN II cosmology as a result of new-generation deep surveys such as the Subaru/Hyper Suprime-Cam survey. Applying the 'standard candle method' to SN 2016jhj (z = 0.3398 ± 0.0002; discovered by HSC) together with a low-redshift sample, we are able to construct the highest-redshift SN II Hubble diagram to date with an observed dispersion of 0.27 mag (i.e. 12-13 per cent in distance). This work demonstrates the bright future of SN II cosmology in the coming era of large, wide-field surveys like that of the Large Synoptic Survey Telescope.

  5. Accurate weak lensing of standard candles. II. Measuring σ8 with supernovae

    Science.gov (United States)

    Quartin, Miguel; Marra, Valerio; Amendola, Luca

    2014-01-01

    Soon the number of type Ia supernova (SN) measurements should exceed 100 000. Understanding the effect of weak lensing by matter structures on the supernova brightness will then be more important than ever. Although SN lensing is usually seen as a source of systematic noise, we will show that it can be in fact turned into signal. More precisely, the non-Gaussianity introduced by lensing in the SN Hubble diagram dispersion depends rather sensitively on the amplitude σ8 of the matter power spectrum. By exploiting this relation, we are able to predict constraints on σ8 of 7% (3%) for a catalog of 100 000 (500 000) SNe of average magnitude error 0.12, without having to assume that such intrinsic dispersion and its redshift evolution are known a priori. The intrinsic dispersion has been assumed to be Gaussian; possible intrinsic non-Gaussianities in the data set (due to the SN themselves and/or to other transients) could be potentially dealt with by means of additional nuisance parameters describing higher moments of the intrinsic dispersion distribution function. This method is independent of and complementary to the standard methods based on cosmic microwave background, cosmic shear, or cluster abundance observables.

  6. A Hubble Space Telescope survey for novae in M87 - III. Are novae good standard candles 15 d after maximum brightness?

    Science.gov (United States)

    Shara, Michael M.; Doyle, Trisha F.; Pagnotta, Ashley; Garland, James T.; Lauer, Tod R.; Zurek, David; Baltz, Edward A.; Goerl, Ariel; Kovetz, Attay; Machac, Tamara; Madrid, Juan P.; Mikołajewska, Joanna; Neill, J. D.; Prialnik, Dina; Welch, D. L.; Yaron, Ofer

    2018-02-01

    Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope (HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables. We have recently used these light curves to demonstrate that the observational scatter in the so-called maximum-magnitude rate of decline (MMRD) relation for classical novae is so large as to render the nova-MMRD useless as a standard candle. Here, we demonstrate that a modified Buscombe-de Vaucouleurs hypothesis, namely that novae with decline times t2 > 10 d converge to nearly the same absolute magnitude about two weeks after maximum light in a giant elliptical galaxy, is supported by our M87 nova data. For 13 novae with daily sampled light curves, well determined times of maximum light in both the F606W and F814W filters, and decline times t2 > 10 d we find that M87 novae display M606W,15 = -6.37 ± 0.46 and M814W,15 = -6.11 ± 0.43. If very fast novae with decline times t2 < 10 d are excluded, the distances to novae in elliptical galaxies with stellar binary populations similar to those of M87 should be determinable with 1σ accuracies of ± 20 per cent with the above calibrations.

  7. Violent flickering in Black Holes

    Science.gov (United States)

    2008-10-01

    Unique observations of the flickering light from the surroundings of two black holes provide new insights into the colossal energy that flows at their hearts. By mapping out how well the variations in visible light match those in X-rays on very short timescales, astronomers have shown that magnetic fields must play a crucial role in the way black holes swallow matter. Flickering black hole ESO PR Photo 36/08 Flickering black hole Like the flame from a candle, light coming from the surroundings of a black hole is not constant -- it flares, sputters and sparkles. "The rapid flickering of light from a black hole is most commonly observed at X-ray wavelengths," says Poshak Gandhi, who led the international team that reports these results. "This new study is one of only a handful to date that also explore the fast variations in visible light, and, most importantly how these fluctuations relate to those in X-rays." The observations tracked the shimmering of the black holes simultaneously using two different instruments, one on the ground and one in space. The X-ray data were taken using NASA's Rossi X-ray Timing Explorer satellite. The visible light was collected with the high speed camera ULTRACAM, a visiting instrument at ESO's Very Large Telescope (VLT), recording up to 20 images a second. ULTRACAM was developed by team members Vik Dhillon and Tom Marsh. "These are among the fastest observations of a black hole ever obtained with a large optical telescope," says Dhillon. To their surprise, astronomers discovered that the brightness fluctuations in the visible light were even more rapid than those seen in X-rays. In addition, the visible-light and X-ray variations were found not to be simultaneous, but to follow a repeated and remarkable pattern: just before an X-ray flare the visible light dims, and then surges to a bright flash for a tiny fraction of a second before rapidly decreasing again. None of this radiation emerges directly from the black hole, but from the

  8. Z boson as ``the standard candle'' for high-precision W boson physics at LHC TH1"-->

    Science.gov (United States)

    Krasny, M. W.; Fayette, F.; Płaczek, W.; Siódmok, A.

    2007-08-01

    In this paper we propose a strategy for measuring the inclusive W boson production processes at LHC. This strategy exploits simultaneously the unique flexibility of the LHC collider in running variable beam particle species at variable beam energies, and the configuration flexibility of the LHC detectors. We propose their concrete settings for a precision measurement of the standard model parameters. These dedicated settings optimise the use of the Z boson and Drell Yan-pair production processes as “the standard reference candles”. The presented strategy allows one to factorise and to directly measure those of the QCD effects that affect differently the W and Z production processes. It reduces to a level of mathcal{O}(10^{-4}) the impact of uncertainties in the partonic distribution functions (PDFs) and in the transverse momentum of the quarks on the measurement precision. Last but not the least, it reduces by a factor of 10 the impact of systematic measurement errors, such as the energy scale and the measurement resolution, on the W boson production observables.

  9. Stellar candles for the extragalactic distance scale

    CERN Document Server

    Gieren, Wolfgang

    2003-01-01

    This volume reviews the current status with respect to both theory and observation of the extragalactic distance scale. A sufficient accuracy is required both for a precise determination of the cosmological parameters and also in order to achieve a better understanding of physical processes in extragalactic systems. The "standard candles", used to set up the extragalactic distance scale, reviewed in this book include cepheid variables, RR Lyrae variables, novae, Type Ia and Type II supernovae as well as globular clusters and planetary nebulae.

  10. Flickering aurora observations at 500 frames per second

    Science.gov (United States)

    McHarg, M. G.; Hampton, D. L.; Stenbaek-Nielsen, H.; Michell, R.

    2017-12-01

    Flickering aurora is thought to be produced when incoming energetic electrons are bunched by Oxygen ion cyclotron waves. The light resulting from the bunched electrons then carry information about the wave particle interactions which cause the bunching. Flickering aurora observed by standard frame rate camera shown a pronounced narrow frequency "flicker" at 3-10 Hz. This frequency matches the ion cyclotron frequency of oxygen ions at altitudes between 2000-5000km. We report on observations of flickering aurora which were obtained at 500 frames per second using an intensified Phantom high speed camera with a 20 degree field of view at magnetic zenith on 2 March 2017. In addition to the narrow frequency results previously reported with standard frame rate imagers, we observe broad band frequencies up to approximately 30 Hz. We report on the spatial distribution of both the narrow and broad band frequency modulations, and compare these to various theoretical models of flickering aurora.

  11. Rod Photoreceptors Detect Rapid Flicker

    Science.gov (United States)

    Conner, J. D.; MacLeod, Donald I. A.

    1977-01-01

    Rod-isolation techniques show that light-adapted human rods detect flicker frequencies as high as 28 hertz, and that the function relating rod critical flicker frequency to stimulus intensity contains two distinct branches. (MLH)

  12. Visual discomfort and flicker.

    Science.gov (United States)

    Yoshimoto, Sanae; Garcia, Jesel; Jiang, Fang; Wilkins, Arnold J; Takeuchi, Tatsuto; Webster, Michael A

    2017-09-01

    Flickering lights can be uncomfortable to look at and can induce seizures in observers with photosensitive epilepsy. However, the temporal characteristics contributing to these effects are not fully known. In the spatial domain, one identified source of visual discomfort is when images have Fourier amplitude spectra that deviate from the natural (∼1/frequency, 1/f) statistical characteristics of natural scenes, especially if they contain excess energy at the medium frequencies at which the visual system is most sensitive. We tested for analogous effects in the temporal domain, manipulating both the amplitude and phase spectra of the flicker. Participants judged the relative discomfort of temporal luminance variations in a pair of uniform 17° fields with different temporal modulations. In general, discomfort increased with deviations from natural amplitude spectra, particularly those with excess energy at medium frequencies or biased toward sharper spectra. These ratings of discomfort were also consistent with ratings of how natural the modulations appeared. However, the temporal discomfort judgments were also strongly affected by the phase spectra of the flicker, with fixed vs. random spectra producing very different responses. This was not due to the perceived regularity or predictability of the flicker, but could arise from a number of other potential factors. Our findings suggest that, like spatial patterns, visual discomfort in time-varying patterns depends in part on how similar they are to the amplitude spectra of temporal variations in the natural visual environment, but also point to the critical role of the phase spectrum in the perceived discomfort of flicker. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Flicker suppressor by thyristor

    International Nuclear Information System (INIS)

    Masuda, M.; Matsumoto, S.; Shintomi, T.

    1977-01-01

    One of the difficulties which are encountered by direct connection of the accelerator to the utilities is the effect of pulsed reactive power on the utilities with respect to the customer's interference and the system stability. To suppress the voltage flickers caused by the pulsed reactive power, several types of machines have been investigated, namely capacitor banks with thyristor switches, series capacitors, saturable reactor and reactor with thyristors. Among these, the reactor with thyristors was employed in KEK accelerator with respect to performance, maintenance, technical feasibility and economical point. The actual operation of reactive power control by ignition angle of thyristor was satisfactory. The swing of 14 MVAr reactive power was stabilized within +-5% and the voltage flicker was suppressed from 3% to 0.5% which is enough less than the permissible value suggested by the electrical company. The harmonic current which is asociated with thyristor was absorbed to ac filters that also served as the reactive power compensator

  14. Candle Flames in Microgravity Video

    Science.gov (United States)

    1997-01-01

    This video of a candle flame burning in space was taken by the Candle Flames in Microgravity (CFM) experiment on the Russian Mir space station. It is actually a composite of still photos from a 35mm camera since the video images were too dim. The images show a hemispherically shaped flame, primarily blue in color, with some yellow early int the flame lifetime. The actual flame is quite dim and difficult to see with the naked eye. Nearly 80 candles were burned in this experiment aboard Mir. NASA scientists have also studied how flames spread in space and how to detect fire in microgravity. Researchers hope that what they learn about fire and combustion from the flame ball experiments will help out here on Earth. Their research could help create things such as better engines for cars and airplanes. Since they use very weak flames, flame balls require little fuel. By studying how this works, engineers may be able to design engines that use far less fuel. In addition, microgravity flame research is an important step in creating new safety precautions for astronauts living in space. By understanding how fire works in space, the astronauts can be better prepared to fight it.

  15. Organic aerosol formation in citronella candle plumes

    OpenAIRE

    Bothe, Melanie; Donahue, Neil McPherson

    2010-01-01

    Citronella candles are widely used as insect repellants, especially outdoors in the evening. Because these essential oils are unsaturated, they have a unique potential to form secondary organic aerosol (SOA) via reaction with ozone, which is also commonly elevated on summer evenings when the candles are often in use. We investigated this process, along with primary aerosol emissions, by briefly placing a citronella tealight candle in a smog chamber and then adding ozone to the chamber. In rep...

  16. A Hubble Space Telescope Survey for Novae in M87. II. Snuffing out the Maximum Magnitude–Rate of Decline Relation for Novae as a Non-standard Candle, and a Prediction of the Existence of Ultrafast Novae

    Energy Technology Data Exchange (ETDEWEB)

    Shara, Michael M.; Doyle, Trisha; Zurek, David [Department of Astrophysics, American Museum of Natural History, Central Park West and 79th Street, New York, NY 10024-5192 (United States); Lauer, Tod R. [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States); Baltz, Edward A. [KIPAC, SLAC, 2575 Sand Hill Road, M/S 29, Menlo Park, CA 94025 (United States); Kovetz, Attay [School of Physics and Astronomy, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv (Israel); Madrid, Juan P. [CSIRO, Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Mikołajewska, Joanna [N. Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, PL 00-716 Warsaw (Poland); Neill, J. D. [California Institute of Technology, 1200 East California Boulevard, MC 278-17, Pasadena CA 91125 (United States); Prialnik, Dina [Department of Geosciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978 (Israel); Welch, D. L. [Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4M1, Ontario (Canada); Yaron, Ofer [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel)

    2017-04-20

    The extensive grid of numerical simulations of nova eruptions from the work of Yaron et al. first predicted that some classical novae might significantly deviate from the Maximum Magnitude–Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giant elliptical galaxy M87 as they are in the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10{sup −7}–10{sup −8} M {sub ⊙}, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. These same models predict the existence of ultrafast novae that display decline times, t {sub 2,} to be as short as five hours. We outline a strategy for their future detection.

  17. Electrochemical supercapacitor behaviour of functionalized candle ...

    Indian Academy of Sciences (India)

    ... and G (graphite) phase of carbon present in the candle soots. The electrochemical characterization was performed by cyclic voltammetry, galvanostatic charge/discharge test and impedance spectroscopy in 1MH2SO4 electrolyte. The functionalized candle soot electrode showed an enhanced specific capacitance value of ...

  18. 75 FR 44224 - Grant of Authority for Subzone Status; Yankee Candle Corporation (Candles and Gift Sets); Whately...

    Science.gov (United States)

    2010-07-28

    ... Status; Yankee Candle Corporation (Candles and Gift Sets); Whately and South Deerfield, MA Pursuant to... special-purpose subzone at the candle and gift set manufacturing and distribution facilities of Yankee... activity related to the manufacturing and distribution of candles and gift sets at the facilities of Yankee...

  19. A Simple Predictive Method of Critical Flicker Detection for Human Healthy Precaution

    Directory of Open Access Journals (Sweden)

    Goh Zai Peng

    2015-01-01

    Full Text Available Interharmonics and flickers have an interrelationship between each other. Based on International Electrotechnical Commission (IEC flicker standard, the critical flicker frequency for a human eye is located at 8.8 Hz. Additionally, eye strains, headaches, and in the worst case seizures may happen due to the critical flicker. Therefore, this paper introduces a worthwhile research gap on the investigation of interrelationship between the amplitudes of the interharmonics and the critical flicker for 50 Hz power system. Consequently, the significant findings obtained in this paper are the amplitudes of two particular interharmonics are able to detect the critical flicker. In this paper, the aforementioned amplitudes are detected by adaptive linear neuron (ADALINE. After that, the critical flicker is detected by substituting the aforesaid amplitudes to the formulas that have been generated in this paper accordingly. Simulation and experimental works are conducted and the accuracy of the proposed algorithm which utilizes ADALINE is similar, as compared to typical Fluke power analyzer. In a nutshell, this simple predictive method for critical flicker detection has strong potential to be applied in any human crowded places (such as offices, shopping complexes, and stadiums for human healthy precaution purpose due to its simplicity.

  20. Electrochemical supercapacitor behaviour of functionalized candle ...

    Indian Academy of Sciences (India)

    diamond) and G (graphite) phase of carbon present in the candle soots. The electrochemical characterization was performed by cyclic voltammetry, galvanostatic charge/discharge test and impedance spectroscopy in 1MH2SO4 electrolyte.

  1. 16 CFR 501.7 - Candles.

    Science.gov (United States)

    2010-01-01

    ... quantity of contents shall be expressed in terms of count and measure (e.g., length and diameter), to the extent that diameter of such candles need not be expressed. The requirements of § 500.7 of this chapter...

  2. No attentional capture from invisible flicker.

    Science.gov (United States)

    Alais, David; Locke, Shannon M; Leung, Johahn; Van der Burg, Erik

    2016-07-05

    We tested whether fast flicker can capture attention using eight flicker frequencies from 20-96 Hz, including several too high to be perceived (>50 Hz). Using a 480 Hz visual display rate, we presented smoothly sampled sinusoidal temporal modulations at: 20, 30, 40, 48, 60, 69, 80, and 96 Hz. We first established flicker detection rates for each frequency. Performance was at or near ceiling until 48 Hz and dropped sharply to chance level at 60 Hz and above. We then presented the same flickering stimuli as pre-cues in a visual search task containing five elements. Flicker location varied randomly and was therefore congruent with target location on 20% of trials. Comparing congruent and incongruent trials revealed a very strong congruency effect (faster search for cued targets) for all detectable frequencies (20-48 Hz) but no effect for faster flicker rates that were detected at chance. This pattern of results (obtained with brief flicker cues: 58 ms) was replicated for long flicker cues (1000 ms) intended to allow for entrainment to the flicker frequency. These results indicate that only visible flicker serves as an exogenous attentional cue and that flicker rates too high to be perceived are completely ineffective.

  3. The flicker spectrum of AE Aquarii

    International Nuclear Information System (INIS)

    Elsworth, Y.P.; James, J.F.

    1982-01-01

    The technique of High-Speed Fourier Transform photometry has been used to observe the flickering activity on AE Aqr up to the frequency limit imposed by photon shot noise. The flicker spectrum exhibits an inverse relation between amplitude and frequency to the observable limit of 0.5 Hz. Some conclusions are drawn from this about the nature of the mechanism responsible for the flickering. The presence of appreciable amounts of flickering above 0.1 Hz places a limit on the opacity of the emitting region. (author)

  4. Flicker Interaction Studies and Flickermeter Improvement

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Rong

    2009-06-04

    Flicker is one of the most important power quality aspects. It is the noticeable light intensity variation of a lamp caused by rapid voltage fluctuations in the electrical power system. It is annoying to human eyes. In the Netherlands, the grid operators' database of complaints on voltage quality shows that almost 60% of all complaints are about flicker. The statistical measurement database shows that the average long-term flicker indicator P{sub lt} increased from 1996 to 2004 in the low-voltage grid in the Netherlands. The evaluation and measurement of flicker becomes therefore an important issue. Firstly, the research aimed at the improvement of the classical flicker measurement method, i.e. the UIE/IEC flickermeter method. Since nowadays more and more lamp types are applied in the market, the world-wide used UIE/IEC flickermeter cannot generate results (P{sub st}) that correlate well with the customer sensitivity for different lamp types. This is due to the fact that the UIE/IEC flickermeter model is built by only considering the incandescent lamp as the reference lamp. Flicker response (illuminance flicker response) measurements of five lamp types (the incandescent lamp, fluorescent lamp, halogen lamp, energy saving lamp and LED lamp) have been made in the Power Quality Lab of TUE. To analyze and evaluate the measured data, Fourier analysis is done and different filter types are tested using Matlab. The five lamp types flicker response models are derived by using linear system identification methods based on the results of the flicker response (illuminance flicker response) measurements. The lamp flicker response models are studied and tested by using the Matlab/System Identification Toolbox. These lamp flicker response models are implemented into the improved flickermeter models, which can provide the better match between the output and customer complaints for specific lamp types. Secondly, light spectrum flicker response measurements of different lamp

  5. Social and Economic Impact of the Candle Light Source Project Candle project impact

    Science.gov (United States)

    Baghiryan, M.

    Social and economic progress related to the realization of the CANDLE synchrotron light source creation project in Armenia is discussed. CANDLE service is multidisciplinary and long-lasting. Its impacts include significant improvement in science capacities, education quality, industrial capabilities, investment climate, country image, international relations, health level, restraining the "brain-drain", new workplaces, etc. CANDLE will serve as a universal national infrastructure assuring Armenia as a country with knowledge-based economy, a place for doing high-tech business, and be a powerful tool in achieving the country's jump forward in general.

  6. 75 FR 63200 - Petroleum Wax Candles From China

    Science.gov (United States)

    2010-10-14

    ... COMMISSION Petroleum Wax Candles From China AGENCY: United States International Trade Commission. ACTION: Scheduling of an expedited five-year review concerning the antidumping duty order on petroleum wax candles... whether revocation of the antidumping duty order on petroleum wax candles from China would be likely to...

  7. 75 FR 80843 - Petroleum Wax Candles From China

    Science.gov (United States)

    2010-12-23

    ... COMMISSION Petroleum Wax Candles From China Determination On the basis of the record \\1\\ developed in the... antidumping duty order on petroleum wax candles from China would be likely to lead to continuation or... Petroleum Wax Candles from China: Investigation No. 731-TA-282 (Third Review). Issued: December 17, 2010. By...

  8. Flicker emission levels from wind turbines

    International Nuclear Information System (INIS)

    Soerensen, P.; Tande, J.O.; Soendergaard, L.M.

    1996-01-01

    The paper presents and verifies a method to calculate the flicker emission levels from wind turbines connected to power distribution systems. The idea of the method is to measure the flicker emission level from a wind turbine with reference conditions and to use these measurements to calculate a flicker coefficient for that specific wind turbine type. This can be done as a part of the approval of a wind turbine type. The flicker coefficient can then be used to calculate the flicker emission level from any wind turbine of that type with any grid and wind conditions. A simple method to determine the total flicker emission level from a number of wind turbines is also presented and verified. The flicker coefficient method is applied to 4 Danish wind turbine types representing stall and pitch control and nominal power from 300 kW to 500 kW. The conclusion is that the flicker emission in certain cases exceeds limits which are expected to be normative in the future. (author)

  9. Flicker Ball, Physical Education: 5551.34.

    Science.gov (United States)

    Stout, Paul L.

    This course outline is a guide for teaching skills of flicker ball in grades 7-12. The course format includes lectures, game situations, class tournaments, and tests that focus on mastery of skills, understanding of rules, and development of techniques in shooting and passing. Course content includes the following: (a) history of flicker ball, (b)…

  10. Gamma flicker elicits positive affect without awareness.

    Science.gov (United States)

    Heerebout, Bram T; Tap, A E Yoram; Rotteveel, Mark; Phaf, R Hans

    2013-03-01

    High-frequency oscillations emerged as a neural code for both positive affect and fluent attentional processing from evolutionary simulations with artificial neural networks. Visual 50 Hz flicker, which entrains neural oscillations in the gamma band, has been shown to foster attentional switching, but can it also elicit positive affect? A three-faces display (2-female/1-male or 2-male/1-female) was preceded by a 50, 25, or 0 Hz flicker on the position of the odd-one-out (i.e., the target). Participants decided on the gender (Block 1) or on the subjective valence (Block 2) of this neutral target in an approach-avoidance task, which served as an implicit affective measure. Only the detection of 25 Hz flicker, but not of 50 Hz flicker, was above chance (Block 3). Faces primed by invisible 50 Hz flicker were explicitly evaluated more positively than with 25 Hz or 0 Hz. This gamma flicker also facilitated approach reactions, and inhibited avoidance reactions relative to 25 Hz and 0 Hz flicker in Blocks 1 and 2. Attentional switching was, moreover, enhanced by the 50 Hz flicker. According to the Affect-Gamma hypothesis, also in biological neural networks, high-frequency gamma oscillations may code for positive affect. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Progress in research on chlorate candle technology

    Science.gov (United States)

    Littman, J.

    1970-01-01

    Research and development program improves sodium chlorate candle formulation, production method, and igniter design. Cobalt is used as the fuel, dry processing methods are used to lower the water content, and a device based on pyrotechnic heater concepts is used as the igniter.

  12. Electrochemical supercapacitor behaviour of functionalized candle ...

    Indian Academy of Sciences (India)

    diamond) and G (graphite) phase of carbon present in the candle ... bute as a potential material for various modern applications. [27,28]. In recent times, the ... used for bio-imaging application and confirmed that these fluorescent carbon nanoparticles ...

  13. The Chemical History of a Candle

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 3. The Chemical History of a Candle. H R Madhusudan. Book Review Volume 7 Issue 3 March 2002 pp 87-89. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/007/03/0087-0089. Author Affiliations.

  14. Electrochemical supercapacitor behaviour of functionalized candle ...

    Indian Academy of Sciences (India)

    2Department of Ceramic Engineering, Gangneung-Wonju National University, Gangneung 210 702, Republic of Korea. MS received 15 March 2015; accepted 17 August 2015. Abstract. The electrochemical supercapacitor behaviour of bare, washed and nitric acid functionalized candle flame carbon soots were reported.

  15. The Chemical History of a Candle

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 3. The Chemical History of a Candle. Michael Faraday. Classics Volume 7 Issue 3 March 2002 pp 90-98. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/03/0090-0098. Author Affiliations.

  16. The Chemical History of a Candle

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 3. The Chemical History of a Candle. H R Madhusudan. Book Review Volume 7 Issue 3 March 2002 pp 87-89. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/03/0087-0089. Author Affiliations.

  17. [Reproducibility of measurements using the IMEA ADR III critical flicker-fusion frequency measuring device].

    Science.gov (United States)

    Angeli, Orsolya; Veres, Dániel Sándor; Nagy, Zoltán Zsolt; Schneider, Miklós

    2016-07-03

    Measurement of central critical flicker-fusion frequency is a common screening test for eye diseases and additionally it can serve as a useful diagnostic test in numerous neurological and internal diseases. The test might also be used for monitoring purposes. The aim of the authors was to evaluate a digital central critical flicker-fusion frequency measuring device (IMEA ADR III) in 30 young, healthy Hungarian subjects. After a general ophthalmological screening examination, monocular central critical flicker-fusion frequency was measured with four colours. Measurements were carried out on two separate days in three sessions under standardized conditions. Intrasession, intersession and intervisit variabilities, differences in central critical flicker-fusion frequency using the four colours and the effect of certain other influencing factors were determined. There were no statistically significant differences between sessions in the mean and standard deviation of the measurement sets. The central critical flicker-fusion frequency threshold for red colour was significantly lower than for other colours, and the threshold for blue colour was significantly lower than for green. There were no significant differences regarding sex, age, iris colour, and smoking indicating that these factors did not influence the central critical flicker-fusion frequency threshold in these subjects. Measurement results with the device are reliable and reproducible in healthy, young population in separate sessions.

  18. No attentional capture from invisible flicker

    OpenAIRE

    Alais, David; Locke, Shannon M.; Leung, Johahn; Van der Burg, Erik

    2016-01-01

    We tested whether fast flicker can capture attention using eight flicker frequencies from 20?96?Hz, including several too high to be perceived (>50?Hz). Using a 480?Hz visual display rate, we presented smoothly sampled sinusoidal temporal modulations at: 20, 30, 40, 48, 60, 69, 80, and 96?Hz. We first established flicker detection rates for each frequency. Performance was at or near ceiling until 48?Hz and dropped sharply to chance level at 60?Hz and above. We then presented the same flickeri...

  19. The flicker spectrum of YZ Cancri

    International Nuclear Information System (INIS)

    Elsworth, Y.; James, J.F.

    1986-01-01

    High-speed Fourier Transform photometry has been used to observe the light curve of YZ Cancri. The flicker spectrum exhibits an inverse relation between amplitude and frequency with a variable power law, with evidence for a high-frequency cut-off point which is also variable. This is regarded as evidence that the source of the flickering lies within an optically dense region of variable size, and that the size changes when the star is in outburst. (author)

  20. Monocular and binocular mechanisms mediating flicker adaptation.

    Science.gov (United States)

    Zhuang, Xiaohua; Shevell, Steven K

    2015-12-01

    Flicker adaptation reduces subsequent temporal contrast sensitivity. Recent studies show that this adaptation likely results from neural changes in the magnocellular visual pathway, but whether this adaptation occurs at a monocular or a binocular level, or both, is unclear. Here, two experiments address this question. The first experiment exploits the observation that flicker adaptation is stronger at higher than lower temporal frequencies. Observers' two eyes adapted to 3Hz flicker with an incremental pulse at 1/4 duty cycle, either in-phase or out-of-phase in the two eyes. At the binocular level, the flicker rate was 6Hz in the out-of-phase condition if the two eyes' pulse trains sum. Similar sensitivity reduction was found in both phase conditions, as expected for independent monocular adapting mechanisms. The second experiment tested for interocular transfer of adaptation between eyes. Results showed that (1) flicker adaptation was strongest with adapting and test fields in only the same eye, (2) adaptation can be partially transferred interocularly with adaptation in only the opposite eye, and (3) adaptation was weakened when both eyes were adapted simultaneously at different contrasts, compared to test-eye adaptation alone. Taken together, the findings are consistent with mechanisms of flicker adaptation at both the monocular and binocular level. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Deconvolution of high rate flicker electroretinograms.

    Science.gov (United States)

    Alokaily, A; Bóhorquez, J; Özdamar, Ö

    2014-01-01

    Flicker electroretinograms are steady-state electroretinograms (ERGs) generated by high rate flash stimuli that produce overlapping periodic responses. When a flash stimulus is delivered at low rates, a transient response named flash ERG (FERG) representing the activation of neural structures within the outer retina is obtained. Although FERGs and flicker ERGs are used in the diagnosis of many retinal diseases, their waveform relationships have not been investigated in detail. This study examines this relationship by extracting transient FERGs from specially generated quasi steady-state flicker and ERGs at stimulation rates above 10 Hz and similarly generated conventional flicker ERGs. The ability to extract the transient FERG responses by deconvolving flicker responses to temporally jittered stimuli at high rates is investigated at varying rates. FERGs were obtained from seven normal subjects stimulated with LED-based displays, delivering steady-state and low jittered quasi steady-state responses at five rates (10, 15, 32, 50, 68 Hz). The deconvolution method enabled a successful extraction of "per stimulus" unit transient ERG responses for all high stimulation rates. The deconvolved FERGs were used successfully to synthesize flicker ERGs obtained at the same high stimulation rates.

  2. Optical flickering of the symbiotic star CH Cyg

    Science.gov (United States)

    Stoyanov, K. A.; Martí, J.; Zamanov, R.; Dimitrov, V. V.; Kurtenkov, A.; Sánchez-Ayaso, E.; Bujalance-Fernández, I.; Latev, G. Y.; Nikolov, G.

    2018-02-01

    Here we present quasi-simultaneous observations of the flickering of the symbiotic binary star CH Cyg in U, B and V bands. We calculate the flickering source parameters and discuss the possible reason for the flickering cessation in the period 2010-2013.

  3. On the flickering of hot spots in cataclysmic variables

    International Nuclear Information System (INIS)

    James, J.F.

    1987-01-01

    A flickering point source inside a scattering cloud will have its higher flicker frequencies attenuated because of delays caused by multiple scattering of photons in the cloud. The effect of this on the flicker spectrum of a cataclysmic variable is considered. (author)

  4. Flicker Vision of Selected Light Sources

    Science.gov (United States)

    Otomański, Przemysław; Wiczyński, Grzegorz; Zając, Bartosz

    2017-10-01

    The results of the laboratory research concerning a dependence of flicker vision on voltage fluctuations are presented in the paper. The research was realized on a designed measuring stand, which included an examined light source, a voltage generator with amplitude modulation supplying the light source and a positioning system of the observer with respect to the observed surface. In this research, the following light sources were used: one incandescent lamp and four LED luminaires by different producers. The research results formulate a conclusion concerning the description of the influence of voltage fluctuations on flicker viewing for selected light sources. The research results indicate that LED luminaires are less susceptible to voltage fluctuations than incandescent bulbs and that flicker vision strongly depends on the type of LED source.

  5. Why do aged fluorescent tubes flicker?

    Science.gov (United States)

    Plihon, Nicolas; Ferrand, Jérémy; Guyomar, Tristan; Museur, Flavien; Taberlet, Nicolas

    2017-11-01

    Our everyday experience of aged and defective fluorescent tubes or bulbs informs us that they may flicker and emit a clicking sound while struggling to light up. In this article, the physical mechanisms controlling the initial illumination of a functioning fluorescent tube are investigated using a simple and affordable experimental setup. Thermionic emission from the electrodes of the tube controls the startup of fluorescent tubes. The origin of the faulty startup of aged fluorescent tubes is discussed and flickering regimes using functional tubes are artificially produced using a dedicated setup that decreases electron emission by the thermionic effect in a controlled manner. The physical parameters controlling the occurrence of flickering light are discussed, and their temporal statistics are reported.

  6. A measurement method for determining the direction of propagation of flicker and for tracing a flicker source

    OpenAIRE

    Axelberg, Peter; Bollen, Math; Gu, Irene Y.H.

    2005-01-01

    This paper describes a new and highly efficient measurement method (algorithm) that determines how flicker  propagates throughout the network and also traces the dominant flicker source. The fundamental principle of the method is to use the fact that a flicker source produces an amplitude modulation in the voltage and current waveforms. The low frequency variations in voltage and current that cause flicker are retrieved in a demodulation and filtering process. By first multiplying the low fre...

  7. Gamma flicker elicits positive affect without awareness

    NARCIS (Netherlands)

    Heerebout, B.T.; Tap, A.E.Y; Rotteveel, M.; Phaf, R.H.

    2013-01-01

    High-frequency oscillations emerged as a neural code for both positive affect and fluent attentional processing from evolutionary simulations with artificial neural networks. Visual 50 Hz flicker, which entrains neural oscillations in the gamma band, has been shown to foster attentional switching,

  8. EEG-based characterization of flicker perception

    NARCIS (Netherlands)

    Lazo, M.; Tsoneva, T.; Garcia Molina, G.

    2013-01-01

    Steady-State Visual Evoked Potential (SSVEP) is an oscillatory electrical response appearing in the electroencephalogram (EEG) in response to flicker stimulation. The SSVEP manifests more prominently in electrodes located near the visual cortex and has oscillatory components at the stimulation

  9. Spatiotemporal flicker detector model of motion silencing.

    Science.gov (United States)

    Choi, Lark Kwon; Bovik, Alan C; Cormack, Lawrence K

    2014-01-01

    Motion can impair the perception of other visual changes. Suchow and Alvarez (2011a, Current Biology, 21, 140-143) recently demonstrated a striking 'motion silencing' illusion, in which the salient changes among a group of objects' luminances (or colors, etc) appear to cease in the presence of large, coherent object motion. To understand why the visual system might be insensitive to changes in object luminances ('flicker') in the presence of object motion, we constructed similar stimuli and did a systematic spectral analysis of them. We conducted human psychophysical experiments to examine motion silencing as a function of stimulus velocity, flicker frequency, and spacing; and we created a simple filter-based model as a working hypothesis of motion silencing. From the results, we found that the threshold of silencing occurs when the log frequency of object replacement is roughly one quarter of the log flicker frequency (the mean slope is approximately 0.27). The dependence of silencing on object spacing may be explained as a phenomenon of temporal sampling of the stimuli by the visual system. Our proposed model successfully captures the psychophysical data over a wide range of velocities and flicker frequencies.

  10. Radio flux flicker of extragalactic sources

    International Nuclear Information System (INIS)

    Heeschen, D.S.

    1982-01-01

    The author describes observations which indicate that compact sources (compactness evidenced by flat/complex spectra) display a ''flicker'' in their intrinsic centimeter wavelength radiation, with an amplitude of about 2% and a characteristic time scale of a few days. (Auth.)

  11. Flicker-noise measurements of deep implanted silicon layers

    International Nuclear Information System (INIS)

    Gerasimenko, N.N.; Makoviychuk, M.I.

    2001-01-01

    Full text: The implantation of ions causes damage to the lattice structure of the target. In order to restore this lattice damage and put the implanted dopants on substitutional sites an anneal step has to be performed. At this point the question arises whether high energy implantations cause more damage than 'standard' implantations (up to 200 keV) do and whether this damage can be annealed. Therefore an extensive study on the anneal behaviour of ion dose high energy boron implantations is presented in this summary paper, in order to obtain a clear view of the best treatment to remove the damage caused by these implantations. Noise measurements and channeling measurements are presented to get information about the damage caused by implantation and the residual damage after annealing. From noise measurements it can be concluded that at room temperature flicker-noise parameter β S q is proportional to exp(ΔE/kT an ) where ΔE is an activation energy of 1.1 eV and T an the anneal temperature of the samples in Kelvin. The better the crystal, the lower the flicker-noise parameter β S q . This actuation energy is associated with the activation of boron according to the observation

  12. The effect of contrast on perceived speed and flicker.

    Science.gov (United States)

    Hammett, Stephen T; Larsson, Jonas

    2012-11-28

    Slowly moving low contrast patterns appear to drift more slowly than higher contrast patterns. It has been reported that this effect of contrast is reversed for flickering patterns such that they appear to flicker faster than high contrast patterns. This apparent difference in the effect of contrast on perceived speed and flicker may place important constraints upon models of speed encoding in the human visual system. We have measured perceived speed and flicker over a range of spatial and temporal frequencies. The results indicate that contrast has qualitatively (but not quantitatively) similar effects upon perceived speed and flicker. The results also indicate that the effect of contrast upon perceived speed is likely to be inherited from the effect of contrast upon perceived flicker. These findings allow a relaxation of previous constraints upon models of speed encoding.

  13. Initializing a flicker-noise generator

    Science.gov (United States)

    Greenhall, C. A.

    1986-01-01

    The behavior of the stationary process, y(s), resulting from a particular Barnes-Jarvis (1971) flicker-noise generator filter initialization is analyzed along with that of the usual output, y(p), and the results are compared to those derived from the theory of true nonstationary flicker noise. A computer simulation and theoretical analysis indicates that though y(s) and y(p) two-sample variances are almost the same, they have significantly different time-interval errors (TIE). As time increases, up to the useful life of the generator output, more and more of the y(s) TIE is found to be due to the transient part.

  14. Galactic latitude dependence of centimeter-wavelength flicker

    International Nuclear Information System (INIS)

    Heeschen, D.S.; Rickett, B.J.; California Univ., La Jolla)

    1987-01-01

    Small-amplitude flickering of the flux density of extragalactic radio sources has been found at 9 cm by Heeschen (1984). It that paper, it was concluded that there was no apparent dependence of the flicker on Galactic latitude. Here, all the pertinent 9 cm data are reanalyzed, and it is found that flicker amplitude does show a latitude dependence consistent with that expected from interstellar scintillation. 7 references

  15. Contrast affects flicker and speed perception differently

    Science.gov (United States)

    Thompson, P.; Stone, L. S.

    1997-01-01

    We have previously shown that contrast affects speed perception, with lower-contrast, drifting gratings perceived as moving slower. In a recent study, we examined the implications of this result on models of speed perception that use the amplitude of the response of linear spatio-temporal filters to determine speed. In this study, we investigate whether the contrast dependence of speed can be understood within the context of models in which speed estimation is made using the temporal frequency of the response of linear spatio-temporal filters. We measured the effect of contrast on flicker perception and found that contrast manipulations produce opposite effects on perceived drift rate and perceived flicker rate, i.e., reducing contrast increases the apparent temporal frequency of counterphase modulated gratings. This finding argues that, if a temporal frequency-based algorithm underlies speed perception, either flicker and speed perception must not be based on the output of the same mechanism or contrast effects on perceived spatial frequency reconcile the disparate effects observed for perceived temporal frequency and speed.

  16. Unravelling the illusion of flicker fusion.

    Science.gov (United States)

    Umeton, Diana; Read, Jenny C A; Rowe, Candy

    2017-02-01

    For over 150 years, researchers have investigated the anti-predator function of animal patterns. However, this work has mainly focused on when prey remain still, and has only recently started to incorporate motion into the study of defensive coloration. As motion breaks camouflage, a new challenge is to understand how prey avoid predators while moving around their environment, and if a moving prey can ever be camouflaged. We propose that there is a solution to this, in that a 'flicker fusion effect' can change the appearance of the prey in the eyes of their predators to reduce the chances of initial detection. This effect occurs when a high contrast pattern blurs at speed, changing the appearance of the prey, which may help them better match their background. Despite being widely discussed in the literature, the flicker fusion effect is poorly described, there is no clear theoretical framework for testing how it might reduce predation, and the terminology describing it is, at best, rather confusing. Our review addresses these three key issues to enable researchers to formulate precise predictions about when the flicker fusion effect occurs, and to test how it can reduce predation. © 2017 The Author(s).

  17. Attractive Flicker--Guiding Attention in Dynamic Narrative Visualizations.

    Science.gov (United States)

    Waldner, Manuela; Le Muzic, Mathieu; Bernhard, Matthias; Purgathofer, Werner; Viola, Ivan

    2014-12-01

    Focus+context techniques provide visual guidance in visualizations by giving strong visual prominence to elements of interest while the context is suppressed. However, finding a visual feature to enhance for the focus to pop out from its context in a large dynamic scene, while leading to minimal visual deformation and subjective disturbance, is challenging. This paper proposes Attractive Flicker, a novel technique for visual guidance in dynamic narrative visualizations. We first show that flicker is a strong visual attractor in the entire visual field, without distorting, suppressing, or adding any scene elements. The novel aspect of our Attractive Flicker technique is that it consists of two signal stages: The first "orientation stage" is a short but intensive flicker stimulus to attract the attention to elements of interest. Subsequently, the intensive flicker is reduced to a minimally disturbing luminance oscillation ("engagement stage") as visual support to keep track of the focus elements. To find a good trade-off between attraction effectiveness and subjective annoyance caused by flicker, we conducted two perceptual studies to find suitable signal parameters. We showcase Attractive Flicker with the parameters obtained from the perceptual statistics in a study of molecular interactions. With Attractive Flicker, users were able to easily follow the narrative of the visualization on a large display, while the flickering of focus elements was not disturbing when observing the context.

  18. Flicker Mitigation of Grid Connected Wind Turbines Using STATCOM

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2004-01-01

    Grid connected wind turbines may produce flicker during continuous operation. In this paper flicker emission of grid connected wind turbines with doubly fed induction generators is investigated during continuous operation. A STATCOM using PWM voltage source converter (VSC) is connected in shunt...... to the point of common coupling (PCC) to relieve the flicker produced by grid connected wind turbines and the corresponding control scheme is described in detail. Simulation results show that STATCOM is an effective measure to mitigate the flicker level during continuous operation of grid connected wind...

  19. Factors Determining Flicker-Induced Retinal Vasodilation in Healthy Subjects.

    Science.gov (United States)

    Sharifizad, Mozhgan; Witkowska, Katarzyna J; Aschinger, Gerold C; Sapeta, Sabina; Rauch, Alexandra; Schmidl, Doreen; Werkmeister, Rene M; Garhöfer, Gerhard; Schmetterer, Leopold

    2016-06-01

    The purpose of this study was to analyze factors determining retinal arterial and venous responses to stimulation with diffuse luminance flicker in healthy subjects. We retrospectively analyzed results obtained in 374 healthy subjects who had previously participated in clinical studies in our department. A total of 153 subjects underwent a protocol in which flicker stimulation was delivered through the fundus camera at 8 Hz (protocol 1), separating measurement and stimulation light depending on the wavelength, and 221 subjects underwent a protocol in which diffuse luminance flicker was delivered at 12.5 Hz with high modulation depth (protocol 2). We investigated whether sex, systemic blood pressure, baseline vessel size, blood plasma concentration of fasting glucose and hematocrit, and serum concentration of cholesterol, triglycerides, creatinine and C-reactive protein influenced the retinal vascular response to flicker stimulation. Flicker responses in arteries and veins were more pronounced in protocol 2 than in protocol 1 (P flicker was larger in smaller vessels (P between 0.001 and 0.016). In protocol 2 the retinal arterial flicker response was negatively associated with cholesterol serum levels (P = 0.033); in protocol 1, only a tendency toward this effect was observed (P = 0.056). The present analysis indicates that retinal arterial and venous responses to stimulation with diffuse luminance flicker depend on the way the stimulation is delivered through the fundus camera. In addition, the flicker response varied with vessel size, that is, the smaller the vessel width, the larger the flicker response. Finally, our data indicate that, even within the normal range, higher cholesterol serum levels are associated with lower hyperemic flicker responses.

  20. Tallow Candles and Meaty Air in 'Bleak House'

    Directory of Open Access Journals (Sweden)

    Anna Henchman

    2017-12-01

    Full Text Available In Charles Dickens’s 'Bleak House' there is a strange (and disgusting pattern of characters feeling that they can ‘taste’ the air, and that that air tastes either meaty or greasy. Esther notices that snuffing ‘two great office candles in tin candlesticks’ at Mrs Jellyby’s ‘made the room taste strongly of hot tallow’, the mutton or beef fat out of which inexpensive candles were made. In 'Bleak House', candles retain their sheepy atmospheres and release them into the surrounding air when consumed. Mrs Jellyby’s home and Mr Vholes’s office are just two places in which Dickens suggests that the process of turning organic animal bodies into urban commodities (candles, parchment, wigs has not quite been completed. Candles and parchment are part animal, part object, and they constantly threaten to revert back into their animal forms. The commodification of animal bodies occurs primarily in the city, where parts of formerly living bodies are manufactured into things. Filled with the smell of burning chops or a spontaneously combusted human, Dickens’s greasier atmospheres contain animal matter suspended in the air that the characters smell, taste, and touch. Once we realize that the apparent smell of chops and candles is, in fact, Krook’s body, this act of taking the air becomes a form of cannibalism that is at least as unsettling as Michael Pollan’s recent account of cows being fed cow parts in factory farms. Drawing on this insight and on Allen MacDuffie’s analyses of energy systems in 'Bleak House', this article focuses on instances in which Dickens defamiliarizes the human consumption of energy by having his characters unintentionally ingest animal particles. Studying Dickens’s treatment of animal fat suspended in air adds a new dimension to recent work on systems of energy expenditure and exchange in an age of industrial capitalism.

  1. Optimized Design and Discussion on Middle and Large CANDLE Reactors

    Directory of Open Access Journals (Sweden)

    Xiaoming Chai

    2012-08-01

    Full Text Available CANDLE (Constant Axial shape of Neutron flux, nuclide number densities and power shape During Life of Energy producing reactor reactors have been intensively researched in the last decades [1–6]. Research shows that this kind of reactor is highly economical, safe and efficiently saves resources, thus extending large scale fission nuclear energy utilization for thousands of years, benefitting the whole of society. For many developing countries with a large population and high energy demands, such as China and India, middle (1000 MWth and large (2000 MWth CANDLE fast reactors are obviously more suitable than small reactors [2]. In this paper, the middle and large CANDLE reactors are investigated with U-Pu and combined ThU-UPu fuel cycles, aiming to utilize the abundant thorium resources and optimize the radial power distribution. To achieve these design purposes, the present designs were utilized, simply dividing the core into two fuel regions in the radial direction. The less active fuel, such as thorium or natural uranium, was loaded in the inner core region and the fuel with low-level enrichment, e.g. 2.0% enriched uranium, was loaded in the outer core region. By this simple core configuration and fuel setting, rather than using a complicated method, we can obtain the desired middle and large CANDLE fast cores with reasonable core geometry and thermal hydraulic parameters that perform safely and economically; as is to be expected from CANDLE. To assist in understanding the CANDLE reactor’s attributes, analysis and discussion of the calculation results achieved are provided.

  2. Flicker Mitigation of Grid Connected Wind Turbines Using STATCOM

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2004-01-01

    to the point of common coupling (PCC) to relieve the flicker produced by grid connected wind turbines and the corresponding control scheme is described in detail. Simulation results show that STATCOM is an effective measure to mitigate the flicker level during continuous operation of grid connected wind...

  3. Flicker noise of hot holes in silicon at 78 K

    NARCIS (Netherlands)

    Bosman., G.; Zijlstra, R.J.J.; Rheenen, A. van

    1980-01-01

    From flicker-noise data versus applied voltage and current-voltage measurements on a p+πp+ planar silicon device at 78 K we calculated Hooge's parameter α for flicker noise as a function of the electric field strength E0 applied along the 1, 0, 0 crystallographic direction. We found that α(E0)

  4. Asymmetric dynamics of adaptation after onset and offset of flicker

    NARCIS (Netherlands)

    Snippe, H.P.; Poot, L.; Hateren, J.H. van

    2004-01-01

    We measured human psychophysical detection thresholds for test pulses which are superimposed on spatially homogeneous backgrounds that have abrupt onsets and offsets of high-contrast 25 Hz flicker. After the onset of the background flicker, test thresholds reach their steady-state levels within

  5. Finding flicker: critical differences in temporal frequency capture attention.

    Science.gov (United States)

    Cass, John; Van der Burg, Erik; Alais, David

    2011-01-01

    Rapid visual flicker is known to capture attention. Here we show slow flicker can also capture attention under reciprocal temporal conditions. Observers searched for a target line (vertical or horizontal) among tilted distractors. Distractor lines were surrounded by luminance modulating annuli, all flickering sinusoidally at 1.3 or 12.1 Hz, while the target's annulus flickered at frequencies within this range. Search times improved with increasing target/distractor frequency differences. For target-distractor frequency separations >5 Hz reaction times were minimal with high-frequency targets correctly identified more rapidly than low frequency targets (~400 ms). Critically, however, at these optimal frequency separations search times for low and high-frequency targets were unaffected by set size (slow flicker popped out from high flicker, and vice versa), indicating parallel and symmetric search performance when searching for high or low frequency targets. In a "cost" experiment using 1.3 and 12.1 Hz flicker, the unique flickering annulus sometimes surrounded a distractor and, on other trials, surrounded the target. When centered on a distractor, the unique frequency produced a clear and symmetrical search cost. Together, these symmetric pop-out and search costs demonstrate that temporal frequency is a pre-attentive visual feature capable of capturing attention, and that it is relative rather than absolute frequencies that are critical. The shape of the search functions strongly suggest that early visual temporal frequency filters underlie these effects.

  6. Reducing flicker due to ambient illumination in camera captured images

    Science.gov (United States)

    Kim, Minwoong; Bengtson, Kurt; Li, Lisa; Allebach, Jan P.

    2013-02-01

    The flicker artifact dealt with in this paper is the scanning distortion arising when an image is captured by a digital camera using a CMOS imaging sensor with an electronic rolling shutter under strong ambient light sources powered by AC. This type of camera scans a target line-by-line in a frame. Therefore, time differences exist between the lines. This mechanism causes a captured image to be corrupted by the change of illumination. This phenomenon is called the flicker artifact. The non-content area of the captured image is used to estimate a flicker signal that is a key to being able to compensate the flicker artifact. The average signal of the non-content area taken along the scan direction has local extrema where the peaks of flicker exist. The locations of the extrema are very useful information to estimate the desired distribution of pixel intensities assuming that the flicker artifact does not exist. The flicker-reduced images compensated by our approach clearly demonstrate the reduced flicker artifact, based on visual observation.

  7. Flicker of extragalactic radio sources at two epochs

    International Nuclear Information System (INIS)

    Simonetti, J.H.; Cordes, J.M.

    1990-01-01

    The flicker of compact extragalactic sources on day-like time scales is investigated. At 1410 MHz the flat-spectrum sources show larger intensity variations than do the steep-spectrum sources. At 820 MHz measurement noise dominates the source variations, so that observations yield an upper limit to the flicker amplitude at this frequency. The flicker amplitude appears to be weakly dependent upon observing wavelength, possibly increasing with increasing wavelength. No dependence of the intensity or time scale of flicker on galactic coordinates is apparent in this data set, but the number of flat spectrum sources observed may be too small to show any such effects. Evidence is presented that flicker is approximately stable in its characteristics over time scales at least as large as 2 yr. 12 refs

  8. Flickering light a history of neon

    CERN Document Server

    Ribbat, Christoph

    2013-01-01

    Without neon, Las Vegas might still be a sleepy desert town in Nevada and Times Square merely another busy intersection in New York City. Transformed by the installation of these brightly colored signs, these destinations are now world-famous, representing the vibrant heart of popular culture. But for some, neon lighting represents the worst of commercialism. Energized by the conflicting love and hatred people have for neon, Flickering Light explores its technological and intellectual history, from the discovery of the noble gas in late nineteenth-century London to its fading popul

  9. Static and flicker perimetry in age-related macular degeneration.

    Science.gov (United States)

    Luu, Chi D; Dimitrov, Peter N; Wu, Zhichao; Ayton, Lauren N; Makeyeva, Galina; Aung, Khin-Zaw; Varsamidis, Mary; Robman, Luba; Vingrys, Algis J; Guymer, Robyn H

    2013-05-01

    The relationship between clinical severity of age-related macular degeneration (AMD) and macular function has not been well established. In this study, we investigated the correlation between clinical severity and functional deficits as detected by static and flicker perimetry. This cross-sectional study consisted of 279 AMD subjects and 24 control participants. AMD subjects were allocated into 1 of 10 AMD severity groups depending on the status of the designated study eye and the fellow eye, as assessed by color fundus photographs. Visual acuity, and static and flicker perimetry were tested on one eye during the same session. The geometric means, SDs, and percentage of abnormal eyes of static and flicker sensitivity of each AMD severity group were determined and compared. The pattern of change in sensitivity and percentage of abnormal eyes for static perimetry across all AMD severity groups were similar to flicker perimetry. Eyes with drusen > 125 μm (P[static] = 0.018, P[flicker] = 0.024), drusenoid epithelial detachment (P[static and flicker] flicker] flicker sensitivities compared to normal eyes. Static (β-coefficient -1.59, 95% confidence interval [CI] -4.78-1.60) and flicker (β-coefficient -1.29, 95% CI -4.66-2.08) sensitivities declined at a similar rate in eyes that showed clinical signs of progression. Static and flicker perimetry were affected similarly across the spectrum of AMD severity, and methods appeared to be valid techniques for assessing retinal sensitivity in AMD once drusen > 125 μm are present, but before the development of late AMD.

  10. 75 FR 49475 - Petroleum Wax Candles From the People's Republic of China: Preliminary Results of Request for...

    Science.gov (United States)

    2010-08-13

    ... research firm in Malaysia on producers' prices for candles made and sold in Malaysia and stated that the... specially designed for Christmas. That is, they are holiday scenes and symbols. Both candles are square... from the People's Republic of China (PRC). Christmas novelty candles are candles specially designed for...

  11. 75 FR 38121 - Petroleum Wax Candles From China

    Science.gov (United States)

    2010-07-01

    ... paper-cored wicks and containing any amount of petroleum wax, except for candles containing more than 50... investigation. The Commission's designated agency ethics official has advised that a five-year review is not... Office of Government Ethics. Consequently, former employees are not required to seek Commission approval...

  12. Demonstrating Sound Wave Propagation with Candle Flame and Loudspeaker

    Science.gov (United States)

    Hrepic, Zdeslav; Nettles, Corey; Bonilla, Chelsea

    2013-01-01

    The motion of a candle flame in front of a loudspeaker has been suggested as a productive demonstration of the longitudinal wave nature of sound. The demonstration has been used also as a research tool to investigate students' understanding about sound. The underpinning of both applications is the expectation of a horizontal, back-and-forth…

  13. New Scientific Aspects of the "Burning Candle" Experiment

    Science.gov (United States)

    Massalha, Taha

    2016-01-01

    The "burning candle" experiment is used in middle school education programs to prove that air contains a component that is essential to burning (i.e., oxygen). The accepted interpretation taught by teachers in middle school is this: when burning occurs, oxygen is used up, creating an underpressure that causes a rise in water level inside…

  14. Proper Use of Candles During a Power Outage

    Centers for Disease Control (CDC) Podcasts

    2006-08-10

    Home fires are a threat after a natural disaster and fire trucks may have trouble getting to your home. If the power is out, use flashlights or other battery-powered lights if possible, instead of candles.  Created: 8/10/2006 by Emergency Communications System.   Date Released: 8/20/2008.

  15. Using Quasars as Standard Candles for Studying Dark Energy

    DEFF Research Database (Denmark)

    Denney, Kelly D.; Vestergaard, Marianne; Watson, D.

    2012-01-01

    , which relies on the technique of reverberation mapping to measure time delays between the quasar continuum and emission line variability signatures. Measuring this time delay effectively measures the radius between the central source and the emission-line gas. The emission line gas is photo...... forecasts demonstrating the power this method can have over, e.g., SNe, to constrain dark energy parameters by extending to higher redshifts than can currently be probed with any other technique....

  16. Reconstructing cosmological matter perturbations using standard candles and rulers

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Ujjaini [Los Alamos National Laboratory; Sahni, Varun [IUCAA, PUNE; Starobinsky, Alexei A [LANDAU INST, MOSCOW

    2008-01-01

    For a large class of dark energy (DE) models, for which the effective gravitational constant is a constant and there is no direct exchange of energy between DE and dark matter (DM), knowledge of the expansion history suffices to reconstruct the growth factor of linearized density perturbations in the non-relativistic matter component on scales much smaller than the Hubble distance. In this paper, we develop a non-parametric method for extracting information about the perturbative growth factor from data pertaining to the luminosity or angular size distances. A comparison of the reconstructed density contrast with observations of large-scale structure and gravitational lensing can help distinguish DE models such as the cosmological constant and quintessence from models based on modified gravity theories as well as models in which DE and DM are either unified or interact directly. We show that for current supernovae (SNe) data, the linear growth factor at z = 0.3 can be constrained to 5% and the linear growth rate to 6%. With future SNe data, such as expected from the Joint Dark Energy Mission, we may be able to constrain the growth factor to 2%-3% and the growth rate to 3%-4% at z = 0.3 with this unbiased, model-independent reconstruction method. For future baryon acoustic oscillation data which would deliver measurements of both the angular diameter distance and the Hubble parameter, it should be possible to constrain the growth factor at z = 2.5%-9%. These constraints grow tighter with the errors on the data sets. With a large quantity of data expected in the next few years, this method can emerge as a competitive tool for distinguishing between different models of dark energy.

  17. Source detection and propagation of equal frequency voltage flicker in nonradial power system

    OpenAIRE

    DEJAMKHOOY, ABDOLMAJID; DASTFAN, ALI; AHMADYFARD, ALIREZA

    2016-01-01

    Nowadays electric power quality problems such as flicker (voltage fluctuation) are major concerns of electric companies and industrial consumers. Identification of flicker sources is an important stage in the flicker reduction process. Flicker source can be modeled as a nonlinear load whose admittance is intermittent and time-variant. In the steady state, fluctuation of voltage amplitude is a function of the impedance of flicker sources. In this paper, after calculating the gradie...

  18. Flicker Reduction in LED-LCDs with Local Backlight

    DEFF Research Database (Denmark)

    Nadernejad, Ehsan; Mantel, Claire; Burini, Nino

    2013-01-01

    Local backlight dimming of LCD with LED backlight can reduce power consumption and improve quality of displayed images and videos. However, important variations of LED over time produce a visually annoying artifact called flickering. In this work, we propose a new algorithm to reduce flickering...... while maintaining video quality. The proposed algorithm uses an adaptive second order Infinite Impulse Response (IIR) in which coefficients are calculated from the local image features. Experimental results show that the proposed method can reduce flickering while simultaneously keeping similar video...

  19. X-ray and optical flickering in EF Eri

    International Nuclear Information System (INIS)

    Watson, M.G.; King, A.R.; Williams, G.A.

    1987-01-01

    A study is presented of the short-time-scale variability of the polar system EF Eri based on simultaneous hard and soft X-ray monitoring with the EXOSAT observatory and optical photometry from CTIO. The observations are used to investigate the nature of the flickering in this system, and the correlations between the variability in the three bands. The hard X-ray flickering is characterized by a quasi-periodic 10 per cent modulation at approx. 230s. The soft X-ray and optical flickering have higher amplitudes but, in contrast, lack any dominant time-scales. (author)

  20. Spatial Frequency Shifts From Counterphase Flicker and From Simultaneous Contrast.

    Science.gov (United States)

    Kaneko, Sae; Anstis, Stuart

    2017-01-01

    In simultaneous contrast of spatial frequency (SF), a test grating surrounded by a coarser inducing grating looks apparently finer. We combined this effect with another visual illusion; the fact that flickering the inducing grating raises its apparent SF. We found that the inducer's apparent , not physical spatial frequency, drove the simultaneous contrast that it induced into a test grating. Thus, when the inducer was made to flicker, its SF appeared to be higher and consequently, the test's SF appeared lower than before. This suggests that simultaneous contrast of spatial frequency exists further downstream than the flicker-induced increase in perceived SF.

  1. A case of shadow flicker/flashing: assessment and solution

    International Nuclear Information System (INIS)

    Clarke, A.D.

    1991-01-01

    A short study was carried out investigating a reported problem of shadow flicker and flashing from the blades of a turbine. The incidence of this phenomenon was confirmed and the duration and frequency of occurrence assessed. The shadow flicker period would be short and only occur at certain times, but could cause irritation. A device to stop the turbine when shadow flicker occurred was recommended and is described. A recommendation was made that turbines should be sited at least ten diameters distance from habitations, and more if sited to the East/Southwest, and the shadow path identified. (author)

  2. Coverage dependence of FE flicker noise

    International Nuclear Information System (INIS)

    Kleint, Ch.

    1978-01-01

    Field emission flicker noise spectral density functions W(f) have been determined for potassium on W(112) and W(111) single planes. The coverage dependence of the spectral densities W(fsub(j)) shows pronounced maxima and minima, whereas the slopes epsilon obtained from double logarithmic plots of W(f) approximately fsup(-epsilon) vary considerably. Minima and maxima of W(fsub(j)) are assumed to be due to coherent and disordered adlayers, respectively, and the behaviour of the exponents epsilon supports further the proposed observation of order-disorder transitions of the potassium adsorbate. LEED results for W(112)K and W(111)K are in fair agreement with the corresponding coverages from noise measurements. (Auth.)

  3. Smooth Pursuit of Flicker-Defined Motion

    Science.gov (United States)

    Mulligan, Jeffrey B.; Stevenson, Scott B.

    2014-01-01

    We examined the pursuit response to stimuli defined by space-variant flicker of a dense random dot carrier pattern. On each frame, every element of the pattern could change polarity, with a probability given by a two-dimensional Gaussian distribution. A normal distribution produces a circular region of twinkle, while inverting the distribution results in a spot of static texture in a twinkling surround. In this latter case, the carrier texture could be stationary, or could move with the twinkle modulator, thereby producing first-order motion in the region of the spot. While the twinkle-defined spot produces a strong sensation of motion, the complementary stimulus defined by the absence of twinkle does not, when viewed peripherally, it appears to move in steps even when the generating distribution moves smoothly. We examined pursuit responses to these stimuli using two techniques: 1) the eye movement correlogram, obtained by cross-correlating eye velocity with the velocity of a randomly-moving stimulus; and 2) delayed visual feedback, where transient stabilization of a target can produce spontaneous oscillations of the eye, with a period empirically observed to vary linearly with the applied delay. Both techniques provide an estimate of the internal processing time, which can be as short as 100 milliseconds for a first-order target. Assessed by the correlogram method, the response to flicker-defined motion is delayed by more than 100 milliseconds, and significantly weaker (especially in the vertical dimension). When initially presented in the delayed feedback condition, purely saccadic oscillation is observed. One subject eventually developed smooth oscillations (albeit with significant saccadic intrusions), showing a period-versus-delay slope similar to that observed for first-order targets. This result is somewhat surprising, given that we interpret the slope of the period-versus-delay-function as reflecting the balance between position- and velocity

  4. Stimulus edge effects in the measurement of macular pigment using heterochromatic flicker photometry.

    Science.gov (United States)

    Smollon, William E; Wooten, Billy R; Hammond, Billy R

    2015-11-01

    Heterochromatic flicker photometry (HFP) is the most common technique of measuring macular pigment optical density (MPOD). Some data strongly suggest that HFP samples MPOD specifically at the edge of center-fixated circular stimuli. Other data have led to the conclusion that HFP samples over the entire area of the stimulus. To resolve this disparity, MPOD was measured using HFP and a series of solid discs of varying radii (0.25 to 2.0 deg) and with thin annuli corresponding to the edge of those discs. MPOD assessed with the two methods yielded excellent correspondence and linearity: Y=0.01+0.98X , r=0.96. A second set of experiments showed that if a disc stimulus is adjusted for no-flicker (the standard procedure) and simply reduced in size, no flicker is observed despite the higher level of MPOD in the smaller area. Taken together, these results confirm that MPOD is determined at the edge of the measuring stimulus when using stimulus sizes in the range that is in dispute (up to a radius of 0.75 deg). The basis for this edge effect can be explained by quantitative differences in the spatial-temporal properties of the visual field as a function of angular distance from the fixation point.

  5. Flickering in AGB stars: probing the nature of accreting companions

    Science.gov (United States)

    Snaid, S.; Zijlstra, A. A.; McDonald, I.; Barker, Helen; Marsh, T. R.; Dhillon, V. S.

    2018-03-01

    Binary companions to asymptotic giant branch (AGB) stars are an important aspect of their evolution. Few AGB companions have been detected, and in most cases it is difficult to distinguish between main-sequence and white dwarf companions. Detection of photometric flickering, a tracer of compact accretion disks around white dwarfs, can help identify the nature of these companions. In this work, we searched for flickering in four AGB stars suggested to have likely accreting companions. We found no signs for flickering in two targets: R Aqr and V1016 Cyg. Flickering was detected in the other two stars: Mira and Y Gem. We investigated the true nature of Mira's companion using three different approaches. Our results for Mira strongly suggest that its companion is a white dwarf.

  6. Evaluation of cone function by a handheld non-mydriatic flicker electroretinogram device.

    Science.gov (United States)

    Nakamura, Natsuko; Fujinami, Kaoru; Mizuno, Yoshinobu; Noda, Toru; Tsunoda, Kazushige

    2016-01-01

    Full-field electroretinograms (ERGs) are used to evaluate retinal function in patients with various types of hereditary and acquired retinal diseases. However, ERG recordings require relatively invasive procedures, including pupillary dilation and the use of contact lens electrodes. Thus, it would be helpful to have a simpler and noninvasive screening method. The purpose of this study was to determine whether a new, handheld, portable ERG device, RETeval™, can be used to screen patients for cone dysfunction. Thirty-five eyes of 35 patients who had reduced cone responses ascertained by a conventional ERG system using contact lens electrodes were studied. The causative diseases included achromatopsia, cone dystrophy, cone-rod dystrophy, retinitis pigmentosa, choroidal dystrophy, autoimmune retinopathy, and Stargardt disease. The flicker ERGs were recorded with the RETeval™ under undilated conditions with skin electrodes (stimulus strength, 3.0 cd·s/m(2); frequency, 28.3 Hz), and the responses were compared to that of 50 healthy eyes. The amplitudes and implicit times of the fundamental component of the flicker ERGs were analyzed in three age groups: Group A, ≤20 years; Group B, 21-40 years; and Group C, ≥41 years. In all of the age groups, the amplitudes of the ERGs were significantly smaller and the implicit times significantly longer in patients with cone dysfunction than in the control eyes. All but one of the patients had flicker amplitudes lower than the mean -2.0 standard deviation of control eyes. The RETeval™ has a potential of being used to screen for cone dysfunction. The entire examination takes flicker responses do not provide information on the scotopic functions, the RETeval™ device can be used to determine which patients require additional full-field ERG testing with dilated pupils under both scotopic and photopic conditions.

  7. Effects of quantum discreetness and flicker fluctuations of tunnel conductivity

    International Nuclear Information System (INIS)

    Kuzovlev, Yu.E.; Medvedev, Yu.V.; Grishin, A.M.

    2002-01-01

    Using a tunnel contact as an example one shows that interaction of single-electron processes in multielectron system may serve as a source of non-scale flicker low-frequency fluctuations of its conductivity. Interaction implies that quantum probability of electron transition depends on spontaneous changes of situation during the transition. Theory relates flicker fluctuations of tunnel conductivity with discreteness of spectrum of electron states and explains nonlinearity of noise-ampere characteristic observed in nanocomposite [ru

  8. Flicker of extragalactic radio sources and refractive interstellar scintillation

    International Nuclear Information System (INIS)

    Blandford, R.; Narayan, R.; Romani, R.W.

    1986-01-01

    Recent work has identified variability of flat-spectrum extragalactic radio sources at lambdaroughly-equal10 cm with rms amplitude of approx.2%--3% and time scale of days. We show that this ''flicker'' is consistent with intensity fluctuations caused by refractive scintillation in an extended interstellar medium in our Galaxy. Further observation of flicker may allow the structure of suitable sources to be partially resolved on angular scales smaller than those probed by VLBI

  9. Influence of tidal parameters on SeaGen flicker performance.

    Science.gov (United States)

    MacEnri, Joseph; Reed, Matthew; Thiringer, Torbjörn

    2013-02-28

    This paper presents the analysis of the study of the flicker emitted from the 1.2 MW tidal energy converter (TEC), SeaGen, against varying tidal parameters. This paper outlines the main elements of the TEC itself, the environment it is located in and the measurement set up. In this paper, the flicker emitted by the TEC is compared with the different tidal parameters, including flood and ebb tides, tidal speed, water depth and turbulence strength and intensity. Flicker emissions have been calculated from measured data in over 90 measurement (10 min) periods, and all of the tidal parameters vary significantly over that testing period. This allows for a detailed statistical and graphical analysis of the variation of flicker with the variation of the tidal parameters outlined above. It is found, with the exception of tidal speed, that there is no strong relationship between flicker emissions and any other tidal parameter. As SeaGen is an asymmetrical TEC with full blade pitching for flood and ebb generation, it was also found that the expected difference of flicker emissions owing to the effect of the submersed crossbeam was not significant. The TEC harmonic performance versus tidal speed is also presented.

  10. Poststimulus response characteristics of the human cone flicker electroretinogram.

    Science.gov (United States)

    Gowrisankaran, Sowjanya; McAnany, J Jason; Alexander, Kenneth R

    2013-07-01

    At certain temporal frequencies, the human cone flicker electroretinogram (ERG) contains multiple additional responses following the termination of a flicker train. The purpose of this study was to determine whether these poststimulus responses are a continuing response to the terminated flicker train or represent the oscillation of a resonant system. ERGs were recorded from 10 visually normal adults in response to full-field sinusoidally modulated flicker trains presented against a short-wavelength rod-saturating adapting field. The amplitude and timing properties of the poststimulus responses were evaluated within the context of a model of a second-order resonant system. At stimulus frequencies between 41.7 and 71.4 Hz, the majority of subjects showed at least three additional ERG responses following the termination of the flicker train. The interval between the poststimulus responses was approximately constant across stimulus frequency, with a mean of 14.4 ms, corresponding to a frequency of 69.4 Hz. The amplitude and timing characteristics of the poststimulus ERG responses were well described by an underdamped second-order system with a resonance frequency of 70.3 Hz. The observed poststimulus ERG responses may represent resonant oscillations of retinal ON bipolar cells, as has been proposed for electrophysiological recordings of poststimulus responses from retinal ganglion cells. However, further investigation is required to determine the types of retinal neurons involved in the generation of the poststimulus responses of the human flicker ERG.

  11. Properties of Flicker ERGs in Rat Models with Retinal Degeneration.

    Science.gov (United States)

    An, Jing; Guo, Qun; Li, Li; Zhang, Zuoming

    2012-01-01

    Purpose. To describe the characteristics of rod and cone functions in rat models for congenital stationary night blindness (CSNB) and retinal cone dysfunction (RCD). Methods. Rod and cone function were isolated by recording the rod-/cone-driven flicker and blue light flicker electroretinograms (ERGs). Results. During dark adaptation, the amplitudes of flicker ERGs in CSNB rats were lower than those in control rats; the responses of RCD rats were similar to control rats. During light adaptation, the amplitudes of flicker ERGs in CSNB rats were reduced; whereas the responses of RCD rats were not detected. Blue flicker ERGs were not observed in CSNB rats at lower frequencies. The cone driven critical flicker frequencies (CFFs) in control rats were 62 Hz. The rod driven CFF of RCD rats was 20 Hz; whereas the rod-/cone-driven CFF of CSNB rats both were about 25 Hz. Conclusions. The function of the rod system was damaged completely, the cones were the source of vision in CSNB rats. Rod system function is excellent in RCD rat. The rods of albinism rats are sensitive to frequencies less than 20 Hz; whereas the cones are sensitive to frequencies up to 62 Hz.

  12. Light a CANDLE. An innovative burnup strategy of nuclear reactors

    International Nuclear Information System (INIS)

    Sekimoto, Hiroshi

    2005-11-01

    CANDLE is a new burnup strategy for nuclear reactors, which stands for Constant Axial Shape of Neutron Flux, Nuclide Densities and Power Shape During Life of Energy Production. When this candle-like burnup strategy is adopted, although the fuel is fixed in a reactor core, the burning region moves, at a speed proportionate to the power output, along the direction of the core axis without changing the spatial distribution of the number density of the nuclides, neutron flux, and power density. Excess reactivity is not necessary for burnup and the shape of the power distribution and core characteristics do not change with the progress of burnup. It is not necessary to use control rods for the control of the burnup. This booklet described the concept of the CANDLE burnup strategy with basic explanations of excess neutrons and its specific application to a high-temperature gas-cooled reactor and a fast reactor with excellent neutron economy. Supplementary issues concerning the initial core and high burnup were also referred. (T. Tanaka)

  13. Candle light-style OLED: a plausibly human-friendly safe night light

    Science.gov (United States)

    Jou, Jwo-Huei; Chen, Po-Wei; Hsieh, Chun-Yu; Wang, Ching-Chiun; Chen, Chien-Chih; Tung, F.-C.; Chen, Szu-Hao; Wang, Yi-Shan

    2013-09-01

    Candles emit sensationally-warm light with a very-low color-temperature, comparatively most suitable for use at night. In response to the need for such a human-friendly night light, we demonstrate the employment of a high number of candle light complementary organic emitters to generate mimic candle light based on organic light emitting diode (OLED). One resultant candle light-style OLED shows a very-high color rendering index, with an efficacy at least 300 times that of candles or twice that of an incandescent bulb. The device can be fabricated, for example, by using four candle light complementary emitters, namely: red, yellow, green, and sky-blue phosphorescent dyes, vacuum-deposited into two emission layers, separated by a nano-layer of carrier modulation material to maximize both the desirable very-high color rendering index and energy efficiency, while keeping the blue emission very low and red emission high to obtain the desirable low color temperature. With different layer structures, the OLEDs can also show color tunable between that of candle light and dusk-hue. Importantly, a romantic sensation giving and supposedly physiologically-friendly candle light-style emission can hence be driven by electricity in lieu of the hydrocarbon-burning and greenhouse gas releasing candles that were invented 5,000 years ago.

  14. Evaluation of cone function by a handheld non-mydriatic flicker electroretinogram device

    Directory of Open Access Journals (Sweden)

    Nakamura N

    2016-06-01

    Full Text Available Natsuko Nakamura,1 Kaoru Fujinami,1 Yoshinobu Mizuno,2 Toru Noda,2 Kazushige Tsunoda11Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, 2Department of Ophthalmology, National Hospital Organization, National Tokyo Medical Center, Tokyo, JapanPurpose: Full-field electroretinograms (ERGs are used to evaluate retinal function in patients with various types of hereditary and acquired retinal diseases. However, ERG recordings require relatively invasive procedures, including pupillary dilation and the use of contact lens electrodes. Thus, it would be helpful to have a simpler and noninvasive screening method. The purpose of this study was to determine whether a new, handheld, portable ERG device, RETeval™, can be used to screen patients for cone dysfunction.Patients and methods: Thirty-five eyes of 35 patients who had reduced cone responses ascertained by a conventional ERG system using contact lens electrodes were studied. The causative diseases included achromatopsia, cone dystrophy, cone-rod dystrophy, retinitis pigmentosa, choroidal dystrophy, autoimmune retinopathy, and Stargardt disease. The flicker ERGs were recorded with the RETeval™ under undilated conditions with skin electrodes (stimulus strength, 3.0 cd·s/m2; frequency, 28.3 Hz, and the responses were compared to that of 50 healthy eyes. The amplitudes and implicit times of the fundamental component of the flicker ERGs were analyzed in three age groups: Group A, ≤20 years; Group B, 21–40 years; and Group C, ≥41 years.Results: In all of the age groups, the amplitudes of the ERGs were significantly smaller and the implicit times significantly longer in patients with cone dysfunction than in the control eyes. All but one of the patients had flicker amplitudes lower than the mean −2.0 standard deviation of control eyes.Conclusion: The RETeval™ has a potential of being used to screen for cone dysfunction. The entire examination

  15. Using multiple continuous fine particle monitors to characterize tobacco, incense, candle, cooking, wood burning, and vehicular sources in indoor, outdoor, and in-transit settings

    Science.gov (United States)

    Ott, Wayne R.; Siegmann, Hans C.

    This study employed two continuous particle monitors operating on different measurement principles to measure concentrations simultaneously from common combustion sources in indoor, outdoor, and in-transit settings. The pair of instruments use (a) photo-charging (PC) operating on the principle ionization of fine particles that responds to surface particulate polycyclic aromatic hydrocarbons (PPAHs), and (b) diffusion charging (DC) calibrated to measure the active surface area of fine particles. The sources studied included: (1) secondhand smoke (cigarettes, cigars, and pipes), (2) incense (stick and cone), (3) candles used as food warmers, (4) cooking (toasting bread and frying meat), (5) fireplaces and ambient wood smoke, and (6) in-vehicle exposures traveling on California arterials and interstate highways. The ratio of the PC to the DC readings, or the PC/DC ratio, was found to be different for major categories of sources. Cooking, burning toast, and using a "canned heat" food warmer gave PC/DC ratios close to zero. Controlled experiments with 10 cigarettes averaged 0.15 ng mm -2 (ranging from 0.11 to 0.19 ng mm -2), which was similar to the PC/DC ratio for a cigar, although a pipe was slightly lower (0.09 ng mm -2). Large incense sticks had PC/DC ratios similar to those of cigarettes and cigars. The PC/DC ratios for ambient wood smoke averaged 0.29 ng mm -2 on 6 dates, or about twice those of cigarettes and cigars, reflecting a higher ratio of PAH to active surface area. The smoke from two artificial logs in a residential fireplace had a PC/DC ratio of 0.33-0.35 ng mm -2. The emissions from candles were found to vary, depending on how the candles were burned. If the candle flickered and generated soot, a higher PC/DC ratio resulted than if the candle burned uniformly in still air. Inserting piece of metal into the candle's flame caused high PPAH emissions with a record PC/DC reading of 1.8 ng mm -2. In-vehicle exposures measured on 43- and 50-min drives on a

  16. Qualifications of Candle Filters for Combined Cycle Combustion Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tomasz Wiltowski

    2008-08-31

    The direct firing of coal produces particulate matter that has to be removed for environmental and process reasons. In order to increase the current advanced coal combustion processes, under the U.S. Department of Energy's auspices, Siemens Westinghouse Power Corporation (SWPC) has developed ceramic candle filters that can operate at high temperatures. The Coal Research Center of Southern Illinois University (SIUC), in collaboration with SWPC, developed a program for long-term filter testing at the SIUC Steam Plant followed by experiments using a single-filter reactor unit. The objectives of this program funded by the U.S. Department of Energy were to identify and demonstrate the stability of porous candle filter elements for use in high temperature atmospheric fluidized-bed combustion (AFBC) process applications. These verifications were accomplished through extended time slipstream testing of a candle filter array under AFBC conditions using SIUC's existing AFBC boiler. Temperature, mass flow rate, and differential pressure across the filter array were monitored for a duration of 45 days. After test exposure at SIUC, the filter elements were characterized using Scanning Electron Microscopy and BET surface area analyses. In addition, a single-filter reactor was built and utilized to study long term filter operation, the permeability exhibited by a filter element before and after the slipstream test, and the thermal shock resilience of a used filter by observing differential pressure changes upon rapid heating and cooling of the filter. The data acquired during the slipstream test and the post-test evaluations demonstrated the suitability of filter elements in advanced power generation applications.

  17. Humans perceive flicker artifacts at 500 Hz.

    Science.gov (United States)

    Davis, James; Hsieh, Yi-Hsuan; Lee, Hung-Chi

    2015-02-03

    Humans perceive a stable average intensity image without flicker artifacts when a television or monitor updates at a sufficiently fast rate. This rate, known as the critical flicker fusion rate, has been studied for both spatially uniform lights, and spatio-temporal displays. These studies have included both stabilized and unstablized retinal images, and report the maximum observable rate as 50-90 Hz. A separate line of research has reported that fast eye movements known as saccades allow simple modulated LEDs to be observed at very high rates. Here we show that humans perceive visual flicker artifacts at rates over 500 Hz when a display includes high frequency spatial edges. This rate is many times higher than previously reported. As a result, modern display designs which use complex spatio-temporal coding need to update much faster than conventional TVs, which traditionally presented a simple sequence of natural images.

  18. Abnormal 8-Hz flicker electroretinograms in carriers of X-linked retinoschisis.

    Science.gov (United States)

    McAnany, J Jason; Park, Jason C; Collison, Frederick T; Fishman, Gerald A; Stone, Edwin M

    2016-08-01

    To evaluate rod-isolated, cone-isolated, and combined rod and cone flicker electroretinograms (ERGs) as a possible means to identify electrophysiological abnormalities in carriers of X-linked retinoschisis (XLRS). Full-field ERGs were recorded from six carriers of XLRS (aged 34-66 years) and eight normally sighted subjects (aged 27-59 years) under rod-isolated (ERGR), cone-isolated (ERGC), and combined rod and cone (ERGR+C) conditions. ERGs were obtained using a four-primary LED-based ganzfeld photostimulator and standard recording techniques. The four primaries were modulated sinusoidally in phase to achieve combined rod and cone activation (ERGR+C) or in different phases to achieve ERGR and ERGC by means of triple silent substitution. After 30 min of dark adaptation, 8- and 15-Hz ERGR, ERGC, and ERGR+C responses were obtained at a mean luminance level of 24 scot. cd/m(2). Standard ISCEV ERGs were also obtained from each subject. The ISCEV and 15-Hz flicker ERGs were generally within the normal range for the carriers. The 8-Hz ERGR, ERGC, and ERGR+C amplitudes were also generally normal. In contrast, the carriers had ERGR, ERGC, and ERGR+C timing abnormalities, with phase advances beyond the range of normal for the ERGR (four carriers), ERGC (four carriers), and ERGR+C (three carriers). Only one carrier had normal 8-Hz responses under all conditions. The 8-Hz ERG timing abnormalities in five of six carriers indicate that retinal function is not necessarily normal in carriers of XLRS. The 8-Hz flicker ERG may be useful for studying retinal function in these individuals.

  19. 76 FR 773 - Petroleum Wax Candles From the People's Republic of China: Continuation of Antidumping Duty Order

    Science.gov (United States)

    2011-01-06

    ... International Trade Administration Petroleum Wax Candles From the People's Republic of China: Continuation of... the antidumping duty order on petroleum wax candles from the People's Republic of China (``PRC... of initiation of the sunset review of the antidumping duty order on petroleum wax candles from the...

  20. Measurement and analysis methods for flicker at arc furnace installations

    OpenAIRE

    2012-01-01

    M.Ing. \\Vith electrical power networks expanding beyond their original design limits and the various non-linear loads on the network, power quality has become an important issue in electrical engineering. Some of the largest non-linear loads on the power network are arc furnaces used to melt various metal orrs and scrap metal. In this study the focus is on fliCker as a power quality issue and more specifically the measurement and analysis methods of flicker at arc furnace installations. By...

  1. Observations on the CANDLE burn-up in various geometries

    International Nuclear Information System (INIS)

    Seifritz, W.

    2007-01-01

    We have looked at all geometrical conditions under which an auto catalytically propagating burnup wave (CANDLE burn-up) is possible. Thereby, the Sine Gordon equation finds a new place in the burn-up theory of nuclear fission reactors. For a practical reactor design the axially burning 'spaghetti' reactor and the azimuthally burning 'pancake' reactor, respectively, seem to be the most promising geometries for a practical reactor design. Radial and spherical burn-waves in cylindrical and spherical geometry, respectively, are principally impossible. Also, the possible applicability of such fission burn-waves on the OKLO-phenomenon and the GEOREACTOR in the center of Earth, postulated by Herndon, is discussed. A fast CANDLE-reactor can work with only depleted uranium. Therefore, uranium mining and uranium-enrichment are not necessary anymore. Furthermore, it is also possible to dispense with reprocessing because the uranium utilization factor is as high as about 40%. Thus, this completely new reactor type can open a new era of reactor technology

  2. FLICKER AS A TOOL FOR CHARACTERIZING PLANETS THROUGH ASTERODENSITY PROFILING

    Energy Technology Data Exchange (ETDEWEB)

    Kipping, D. M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Bastien, F. A.; Stassun, K. G. [Department of Physics and Astronomy, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States); Chaplin, W. J. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Huber, D. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Buchhave, L. A., E-mail: dkipping@cfa.harvard.edu [Centre for Star and Planet Formation, University of Copenhagen, DK-1350 Copenhagen (Denmark)

    2014-04-20

    Variability in the time series brightness of a star on a timescale of 8 hr, known as ''flicker'', has been previously demonstrated to serve as a proxy for the surface gravity of a star by Bastien et al. Although surface gravity is crucial for stellar classification, it is the mean stellar density that is most useful when studying transiting exoplanets, due to its direct impact on the transit light curve shape. Indeed, an accurate and independent measure of the stellar density can be leveraged to infer subtle properties of a transiting system, such as the companion's orbital eccentricity via asterodensity profiling (AP). We here calibrate flicker to the mean stellar density of 439 Kepler targets with asteroseismology, allowing us to derive a new empirical relation given by log{sub 10}(ρ{sub *} (kg m{sup –3})) = 5.413 – 1.850log{sub 10}(F {sub 8} (ppm)). The calibration is valid for stars with 4500 < T {sub eff} < 6500 K, K{sub P} < 14, and flicker estimates corresponding to stars with 3.25 < log g {sub *} < 4.43. Our relation has a model error in the stellar density of 31.7% and so has ∼8 times lower precision than that from asteroseismology but is applicable to a sample ∼40 times greater. Flicker therefore provides an empirical method to enable AP on hundreds of planetary candidates from present and future missions.

  3. Arc - furnace flicker compensation in Ethiopia | Friedlander | Zede ...

    African Journals Online (AJOL)

    Arc - furnace flicker compensation in Ethiopia. E Friedlander, A Telahun, DJ Young. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  4. Uniaxial flicker analysis of the psychophysical Stiles-Crawford effects

    NARCIS (Netherlands)

    Lochocki, Benjamin; Vohnsen, Brian

    2017-01-01

    Purpose: We report on a semi-automated system for frequency analysis of the Stiles-Crawford effect of the first kind (SCE-I) using flicker methodology designed to gain insight into the temporal dynamics of the perceived visibility for alternating pupil entrance points. We describe the system and its

  5. Attentional facilitation of detection of flicker on moving objects.

    Science.gov (United States)

    Shioiri, Satoshi; Ogawa, Masayuki; Yaguchi, Hirohisa; Cavanagh, Patrick

    2015-01-01

    We investigated the influence of attention and motion on the sensitivity of flicker detection for a target among distractors. Experiment 1 showed that when the target and distractors were moving, detection performance plummeted compared to when they were not moving, suggesting that the most sensitive detectors were local, temporal frequency-tuned receptive fields. With the stimuli in motion, a qualitatively different strategy was required and this led to much reduced performance. Cueing, which specified the target location with 100% validity, had no effect for targets that had little or no motion, suggesting that the flicker was sufficiently salient in this case to attract attention to the target without requiring any search. For targets with medium to high speeds, however, cueing provided a strong increase in sensitivity over uncued performance. This suggests a significant advantage for localizing and tracking the target and so sampling the luminance changes from only one trajectory. Experiment 2 showed that effect of attention was to increase the efficiency and duration of signal integration for the moving target. Overall, the results show that flicker sensitivity for a moving target relies on a much less efficient process than detection of static flicker, and that this less efficient process is facilitated when attention can select the relevant trajectory and ignore the others.

  6. FLICKER AS A TOOL FOR CHARACTERIZING PLANETS THROUGH ASTERODENSITY PROFILING

    International Nuclear Information System (INIS)

    Kipping, D. M.; Bastien, F. A.; Stassun, K. G.; Chaplin, W. J.; Huber, D.; Buchhave, L. A.

    2014-01-01

    Variability in the time series brightness of a star on a timescale of 8 hr, known as ''flicker'', has been previously demonstrated to serve as a proxy for the surface gravity of a star by Bastien et al. Although surface gravity is crucial for stellar classification, it is the mean stellar density that is most useful when studying transiting exoplanets, due to its direct impact on the transit light curve shape. Indeed, an accurate and independent measure of the stellar density can be leveraged to infer subtle properties of a transiting system, such as the companion's orbital eccentricity via asterodensity profiling (AP). We here calibrate flicker to the mean stellar density of 439 Kepler targets with asteroseismology, allowing us to derive a new empirical relation given by log 10 (ρ * (kg m –3 )) = 5.413 – 1.850log 10 (F 8 (ppm)). The calibration is valid for stars with 4500 < T eff < 6500 K, K P < 14, and flicker estimates corresponding to stars with 3.25 < log g * < 4.43. Our relation has a model error in the stellar density of 31.7% and so has ∼8 times lower precision than that from asteroseismology but is applicable to a sample ∼40 times greater. Flicker therefore provides an empirical method to enable AP on hundreds of planetary candidates from present and future missions

  7. Flicker as a tool for characterizing planets though asterodensity profiling

    DEFF Research Database (Denmark)

    Kipping, D. M.; Bastien, F. A.; Stassun, K. G.

    2014-01-01

    Variability in the time series brightness of a star on a timescale of 8 hr, known as "flicker," has been previously demonstrated to serve as a proxy for the surface gravity of a star by Bastien et al. Although surface gravity is crucial for stellar classification, it is the mean stellar density t...

  8. Using critical flicker frequency in the evaluation of visual impairment in preeclamptic women.

    Science.gov (United States)

    Maier, Marina; Brückmann, Andreas; Schleußner, Ekkehard; Schlembach, Dietmar

    2017-04-01

    To assess critical flicker frequency (CFF) in normal uneventful pregnancy and preeclampsia. Case-control observational study at the University Hospital Jena and Outpatient Institute for Prenatal Diagnosis and Preventive Medicine. 25 non-pregnant women, 75 uncomplicated pregnant women in first, second and third trimester, and 15 women with overt preeclampsia. For comparison with preeclamptic patients we matched 15 normal pregnant women (mNP) for age, parity, body mass index, current smoking and family history of cardiovascular disease (CVD). We measured CFF using the portable HEPAtonorm Analyzer (nevoLAB GmbH, Germany). This device generates a flickering red light, starting with a frequency of 60Hz, giving the subjective an impression of a steady light. The participant signifies once the impression of a flickering light is recognized, and this CFF is recorded. Mean CFF and standard deviation is automatically calculated. Statistical analysis was performed using SPSS Version 22 for Windows. Following assessment of normal distribution with Kolmogorov-Smirnow test, comparisons were made with univariate and multivariate ANOVA and with unpaired and paired t test for continuous data and with χ 2 test for categorical data. Critical flicker frequency in healthy pregnant women does not differ from nonpregnant women. No significant differences in CFF measurements exist in first, second, and third trimester. In preeclampsia, CFF is significantly decreased compared to normal pregnant women (PE 38.80±2.16 vs. mNP 46.23±3.37; p=0.000). This alteration persists even some weeks postpartum (PE 41.17±1.13 vs. mNP 46.45±3.44; p=0.003). In preeclamptic women, CFF is decreased indicating an altered endothelial situation. The finding that CFF remains reduced postpartum may be explained by either the effect of preeclampsia on maternal endothelium causing longer lasting damage or indicate a preexisting endothelial disorder. Up to this point, precise responsible mechanisms for altered

  9. Flicker-Induced Time Dilation Does Not Modulate EEG Correlates of Temporal Encoding.

    Science.gov (United States)

    Herbst, Sophie K; Chaumon, Maximilien; Penney, Trevor B; Busch, Niko A

    2015-07-01

    In this study, we used EEG to investigate how visual stimulus dynamics (i.e. flicker) affect the mechanisms of duration perception. Previous studies have demonstrated that flickering visual stimuli are judged longer than equally long non-flickering stimuli. We tested whether this effect of flicker on duration judgments is mediated by changes in temporal encoding during the time interval. Here, temporal encoding refers to the perception of the unfolding of time throughout the temporal interval, also termed the "clock stage" in information processing models of interval timing. We hypothesized that if flicker mediates duration perception by affecting temporal encoding, then the dilation-effect should be reflected by neural correlates of temporal encoding. We presented flickering and steady stimuli in a duration bisection task and found that flicker dilated perceived duration. The EEG analysis allowed us to isolate a putative neural correlate of temporal encoding: a modulation of the amplitude of the contingent negative variation (CNV) by stimuli classified as "long" compared to physically identical stimuli classified as "short". However, flicker did not affect the CNV amplitude, suggesting that flicker does not dilate perceived duration by affecting temporal encoding. Possibly, flicker might affect only later stages of temporal processing such as interval comparison or decision making.

  10. Retinal Vascular and Oxygen Temporal Dynamic Responses to Light Flicker in Humans.

    Science.gov (United States)

    Felder, Anthony E; Wanek, Justin; Blair, Norman P; Shahidi, Mahnaz

    2017-11-01

    To mathematically model the temporal dynamic responses of retinal vessel diameter (D), oxygen saturation (SO2), and inner retinal oxygen extraction fraction (OEF) to light flicker and to describe their responses to its cessation in humans. In 16 healthy subjects (age: 60 ± 12 years), retinal oximetry was performed before, during, and after light flicker stimulation. At each time point, five metrics were measured: retinal arterial and venous D (DA, DV) and SO2 (SO2A, SO2V), and OEF. Intra- and intersubject variability of metrics was assessed by coefficient of variation of measurements before flicker within and among subjects, respectively. Metrics during flicker were modeled by exponential functions to determine the flicker-induced steady state metric values and the time constants of changes. Metrics after the cessation of flicker were compared to those before flicker. Intra- and intersubject variability for all metrics were less than 6% and 16%, respectively. At the flicker-induced steady state, DA and DV increased by 5%, SO2V increased by 7%, and OEF decreased by 13%. The time constants of DA and DV (14, 15 seconds) were twofold smaller than those of SO2V and OEF (39, 34 seconds). Within 26 seconds after the cessation of flicker, all metrics were not significantly different from before flicker values (P ≥ 0.07). Mathematical modeling revealed considerable differences in the time courses of changes among metrics during flicker, indicating flicker duration should be considered separately for each metric. Future application of this method may be useful to elucidate alterations in temporal dynamic responses to light flicker due to retinal diseases.

  11. Using slow-release permanganate candles to remediate PAH-contaminated water

    International Nuclear Information System (INIS)

    Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve

    2012-01-01

    Highlights: ► We quantified the efficacy of slow-release permanganate-paraffin candles to degrade and mineralize PAHs. ► 14 C-labeled PAHs were used to quantify both adsorption and transformation. ► Permanganate-treated PAHs were more biodegradable in soil microcosms. ► A flow-through candle system was used to quantify PAH removal in urban runoff. - Abstract: Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin–KMnO 4 ) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2–4 h. Using 14 C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO 2 ), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet–dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to

  12. Discovery of optical flickering from the symbiotic star EF Aquilae

    Science.gov (United States)

    Zamanov, R. K.; Boeva, S.; Nikolov, Y. M.; Petrov, B.; Bachev, R.; Latev, G. Y.; Popov, V. A.; Stoyanov, K. A.; Bode, M. F.; Martí, J.; Tomov, T.; Antonova, A.

    2017-07-01

    We report optical CCD photometry of the recently identified symbiotic star EF Aql. Our observations in Johnson V and B bands clearly show the presence of stochastic light variations with an amplitude of about 0.2 mag on a time scale of minutes. The observations point toward a white dwarf (WD) as the hot component in the system. It is the 11-th object among more than 200 symbiotic stars known with detected optical flickering. Estimates of the mass accretion rate onto the WD and the mass loss rate in the wind of the Mira secondary star lead to the conclusion that less than 1 per cent of the wind is captured by the WD. Eight further candidates for the detection of flickering in similar systems are suggested.

  13. Field-aligned electron flux oscillations that produce flickering aurora

    International Nuclear Information System (INIS)

    McFadden, J.P.; Carlson, C.W.; Boehm, M.H.; Hallinan, T.J.

    1987-01-01

    Measurements of energetic electrons that produce flickering aurora were made by a pair of sounding rockets launched during a slowly evolving auroral breakup. Both payloads passed through a broad inverted-V structure. A component of the electron distribution function was closely aligned with the magnetic field over a broad energy range that extended form low energies up to the inverted-V differential energy flux peak. High time resolution measurements of the field-aligned component showed the presence of order to magnitude coherent flux oscillations. Source altitudes between 4,000 and 8,000 km were derived from velocity dispersion of the flux oscillations. A ground-based TV camera recorded visual flickering in the vicinity of the payloads' auroral footprints during periods when flux oscillations were present. Measurements are compared with previous observations of electron flux oscillations, and possible sources for the field-aligned component are discussed

  14. Flicker-noise Spectroscopy In Earthquake Prediction Research

    Science.gov (United States)

    Desherevsky, A. V.; Lukk, A. A.; Sidorin, A. Y.; Timashev, S. F.

    It has been found out that a two-component model including a seasonal and a flicker- noise components occurs to be a more adequate model of statistical structure of time series of long-term geophysical observations' data. Unlike a white noise which sig- nifies absence of any relation between the system's current dynamics and past events in it, presence of flicker-noise indicates that such a relation in the system does ex- ist. Flicker-noise pertains a property of scale invariance. It seems natural to relate self-similarity of statistical properties of geophysical parameters' variations on dif- ferent scales to self-similar (fractal) properties of geophysical medium. At the same time self-similar time variations of geophysical parameters may indicate to presence of deterministic chaos in geophysical system's evolution. An important element of a proposed approach is application of stochastic models of preparation of each concrete large seismic event. Instead of regular, for example bay-form precursor variations, occurrence of precursors of another kind associated in particular with variation in parameter fluctuations should be expected. To solve a problem of large earthquakes prediction we use Flicker-Noise Spectroscopy (FNS) as a basis of a new approach proposed by us. The basis of the FNS methodology is a postulate about the impor- tant information significance of sequences of various dynamic irregularities (bursts or spikes, jumps with different characteristic values, discontinuities of derivatives) of the measured temporal, spatial and energetic variables on each level of hierarchical orga- nization of studied systems. A proposed new method using integral values of analyzed signals - power spectra and different moments ("structural functions") of a different order as information relations, has demonstrated principally new opportunities in a search of large earthquake precursors already at a preliminary stage of some data analysis. This research was supported by

  15. Flicker adaptation desensitizes the magnocellular but not the parvocellular pathway.

    Science.gov (United States)

    Zhuang, Xiaohua; Pokorny, Joel; Cao, Dingcai

    2015-05-01

    Anatomical and physiological studies show that in primates, visual information is conveyed through two parallel pathways, including the magnocellular (MC-) and parvocellular (PC-) pathways. However, the functional separation between the two pathways remains controversial and challenging. To resolve this, we show a psychophysical approach to desensitize the inferred MC-pathway of human observers independently of the inferred PC-pathway. The steady-pedestal and pulsed-pedestal paradigms that allow detection and discrimination to be mediated by only the inferred MC- or PC-pathway were used. Three observers (one male, aged 43 years, and two females, aged 33 and 62 years) adapted to either a steadily presented pedestal or a 2- or 10-Hz 50% contrast square-wave modulated luminance flicker. Contrast discrimination thresholds were measured following the flicker adaptation. Flicker adaptation reduces contrast detection and discrimination of the MC-pathway but not the PC-pathway, with larger MC losses from 10-Hz (∼ 0.28 log unit loss, P flicker (∼ 0.13 log unit loss, P < 0.05 for one or two observers depending on stimulus size). Further, our results show that the PC-pathway does not mediate the contrast detection threshold at the background luminance following MC-pathway desensitization. This study demonstrates the feasibility of independently manipulating sensitivity of the MC-pathway in human observers. Our paradigms provide powerful tools to independently investigate the perceptual functions in the MC- and PC-pathways. This could lead to a better understanding of the perceptual functions of these pathways.

  16. Thermodynamic crisis in boiling flow. Observation of the flicker noise

    International Nuclear Information System (INIS)

    Reshetnikov, A.V.; Skripov, V.P.; Koverda, V.P.; Skokov, V.I.

    2003-01-01

    The results of the experimental studies on both the characteristics of the boiling liquid flow (discharge, jet reactive force), emanating through a short channel, and the local pulsations in the flow are presented. The identified effects - the flow critical mode, sharp decrease in the value of the reactive force, pulsations with the 1/f spectrum (the flicker noise) are discussed with attraction of the notion on the boiling thermodynamic crisis [ru

  17. Flicker noise related to electrical double layer dynamics

    International Nuclear Information System (INIS)

    Sanduloviciu, M.; Lozneanu, E.; Avram, C.; Balan, P.; Pohoata, V.; Schrittwieser, R.

    2000-01-01

    Transport of particles and energy by the effect of double layers, self-assembled at the edge of a confined plasma, towards a space charge configuration able to perform natural oscillations, reveals a new mechanism of anomalous transport of particles and energy in plasma devices. Based on these experimental results we suggest a new phenomenological basis for the explanation of flicker noise in fusion devices. (author)

  18. Anomalous properties of weak-link-containing superconductors: flicker noise

    International Nuclear Information System (INIS)

    Sergeenkov, S.A.

    1992-01-01

    Low-frequency magnetic noise spectral density is calculated within the superconductive glass model. The model predicts the existence of both white noise and flicker-like noise ω -α with α strongly dependent on applied magnetic field and temperature. It is shown, in particular, that α increases with field from 0.5 to 1, and that in the critical region 1/√ω-law should prevail in the noise spectrum. (orig.)

  19. Helping enhances productivity in campo flicker (Colaptes campestris) cooperative groups.

    Science.gov (United States)

    Dias, Raphael Igor; Webster, Michael S; Macedo, Regina H

    2015-06-01

    Reproductive adults in many bird species are assisted by non-breeding auxiliary helpers at the nest, yet the impact of auxiliaries on reproduction is variable and not always obvious. In this study, we tested Hamilton's rule and evaluated the effect of auxiliaries on productivity in the facultative cooperative breeder campo flicker (Colaptes campestris campestris). Campo flickers have a variable mating system, with some groups having auxiliaries and others lacking them (i.e., unassisted pairs). Most auxiliaries are closely related to the breeding pair (primary auxiliaries), but some auxiliaries (secondary auxiliaries) are unrelated females that joined established groups. We found no effect of breeder quality (body condition) or territory quality (food availability) on group productivity, but the presence of auxiliaries increased the number of fledglings produced relative to unassisted pairs. Nonetheless, the indirect benefit of helping was small and did not outweigh the costs of delayed breeding and so seemed insufficient to explain the evolution of cooperative breeding in campo flickers. We concluded that some ecological constraints must limit dispersal or independent breeding, making staying in the group a "best-of-a-bad-job" situation for auxiliaries.

  20. Potential biological and ecological effects of flickering artificial light.

    Directory of Open Access Journals (Sweden)

    Richard Inger

    Full Text Available Organisms have evolved under stable natural lighting regimes, employing cues from these to govern key ecological processes. However, the extent and density of artificial lighting within the environment has increased recently, causing widespread alteration of these regimes. Indeed, night-time electric lighting is known significantly to disrupt phenology, behaviour, and reproductive success, and thence community composition and ecosystem functioning. Until now, most attention has focussed on effects of the occurrence, timing, and spectral composition of artificial lighting. Little considered is that many types of lamp do not produce a constant stream of light but a series of pulses. This flickering light has been shown to have detrimental effects in humans and other species. Whether a species is likely to be affected will largely be determined by its visual temporal resolution, measured as the critical fusion frequency. That is the frequency at which a series of light pulses are perceived as a constant stream. Here we use the largest collation to date of critical fusion frequencies, across a broad range of taxa, to demonstrate that a significant proportion of species can detect such flicker in widely used lamps. Flickering artificial light thus has marked potential to produce ecological effects that have not previously been considered.

  1. Quantum theory of flicker noise in metal films

    International Nuclear Information System (INIS)

    Kazakov, Kirill A.

    2008-01-01

    Flicker (1/f γ ) voltage noise spectrum is derived from finite-temperature quantum electromagnetic fluctuations produced by elementary charge carriers in external electric field. It is suggested that deviations of the frequency exponent γ from unity, observed in thin metal films, can be attributed to quantum backreaction of the conducting medium on the fluctuating field of the charge carrier. This backreaction is described phenomenologically in terms of the effective momentum space dimensionality, D. Using the dimensional continuation technique, it is shown that the combined action of the photon heat bath and external field results in a 1/f γ -contribution to the spectral density of the two-point correlation function of electromagnetic field. The frequency exponent is found to be equal to 1+δ, where δ=3-D is a reduction of the momentum space dimensionality. This result is applied to the case of a biased conducting sample, and a general expression for the voltage power spectrum is obtained which possesses all characteristic properties of observed flicker noise spectra. The range of validity of this expression covers well the whole measured frequency band. Gauge independence of the power spectrum is proved. It is shown that the obtained results naturally resolve the problem of divergence of the total noise power. A detailed comparison with the experimental data on flicker noise measurements in metal films is given

  2. Effect of Swirl on Flickering Motion of Diffusion Flame

    Science.gov (United States)

    Gotoda, Hiroshi; Hoo Chuah, Keng; Kushida, Genichiro

    2006-11-01

    The buoyancy-induced oscillation is referred to as the so-called flame flickering and its dynamics are important when revealing mechanism of flame oscillations encountered in some combustion systems. Many aspects of flame oscillation / buoyancy coupling have been extensively explored, but the effect of swirling flow on buoyancy-induced flame flickering has yet to be elucidated. The purpose of the present study is to investigate how the buoyancy-induced flame flickering motion is altered by swirl, using a rotating Bunsen burner. The rotating burner tube (Diameter of the burner tube D0 is 10 mm) is vertically supported by bearings, and rotated by a DC motor through a pulley and belt unit. The fuel injection velocity U (= volume flow rate / cross-sectional area of the burner tube) is varied from 0.1 to 0.3 m/s. The rotational speed of the burner tube N is varied up to 2000 rpm. Variations in the flame motion, oscillation frequency, and flame height as a function of burner rotation rate are presented in detail.

  3. Flicker Mitigation Strategy for a Doubly Fed Induction Generator by Torque Control

    DEFF Research Database (Denmark)

    Zhang, Yunqian; Hu, Weihao; Chen, Zhe

    2014-01-01

    Owing to the rotational sampling of turbulence, wind shear and tower shadow effects grid connected variable speed wind turbines could lead to the power fluctuations which may produce flicker during continuous operation. A model of an megawatt (MW)-level variable speed wind turbine with a doubly fed...... induction generator is presented to investigate the flicker mitigation. Taking advantage of the large inertia of the wind turbine rotor, a generator torque control (GTC) strategy is proposed, so that the power oscillation is stored as the kinetic energy of the wind turbine rotor, thus the flicker emission...... is an effective means for flicker mitigation of variable speed wind turbines during continuous operation....

  4. An SSVEP-based BCI using high duty-cycle visual flicker.

    Science.gov (United States)

    Lee, Po-Lei; Yeh, Chia-Lung; Cheng, John Yung-Sung; Yang, Chia-Yen; Lan, Gong-Yau

    2011-12-01

    Steady-state visual-evoked potential (SSVEP)-based brain-computer interfaces (BCIs) have generated significant interest due to their high information transfer rate (ITR). Due to the amplitude-frequency characteristic of the SSVEP, the flickering frequency of an SSVEP-based BCI is typically lower than 20  Hz to achieve a high SNR. However, a visual flicker with a flashing frequency below the critical flicker-fusion frequency often makes subjects feel flicker jerky and causes visual discomfort. This study presents a novel technique using high duty-cycle visual flicker to decrease user's visual discomfort. The proposed design uses LEDs flashing at 13.16  Hz, driven by flickering sequences consisting of repetitive stimulus cycles with a duration T (T = 76 ms). Each stimulus cycle included an ON state with a duration T(ON) and an OFF state with a duration T(OFF) (T = T(ON) + T(OFF)), and the duty cycle, defined as T(ON)/T, varied from 10.5% to 89.5%. This study also includes a questionnaire survey and analyzes the SSVEPs induced by different duty-cycle flickers. An 89.5% duty-cycle flicker, reported as a comfortable flicker, was adopted in a phase-tagged SSVEP system. Six subjects were asked to sequentially input a sequence of cursor commands with the 25.08-bits/min ITR.

  5. Individual Alpha Peak Frequency Predicts 10 Hz Flicker Effects on Selective Attention.

    Science.gov (United States)

    Gulbinaite, Rasa; van Viegen, Tara; Wieling, Martijn; Cohen, Michael X; VanRullen, Rufin

    2017-10-18

    Rhythmic visual stimulation ("flicker") is primarily used to "tag" processing of low-level visual and high-level cognitive phenomena. However, preliminary evidence suggests that flicker may also entrain endogenous brain oscillations, thereby modulating cognitive processes supported by those brain rhythms. Here we tested the interaction between 10 Hz flicker and endogenous alpha-band (∼10 Hz) oscillations during a selective visuospatial attention task. We recorded EEG from human participants (both genders) while they performed a modified Eriksen flanker task in which distractors and targets flickered within (10 Hz) or outside (7.5 or 15 Hz) the alpha band. By using a combination of EEG source separation, time-frequency, and single-trial linear mixed-effects modeling, we demonstrate that 10 Hz flicker interfered with stimulus processing more on incongruent than congruent trials (high vs low selective attention demands). Crucially, the effect of 10 Hz flicker on task performance was predicted by the distance between 10 Hz and individual alpha peak frequency (estimated during the task). Finally, the flicker effect on task performance was more strongly predicted by EEG flicker responses during stimulus processing than during preparation for the upcoming stimulus, suggesting that 10 Hz flicker interfered more with reactive than proactive selective attention. These findings are consistent with our hypothesis that visual flicker entrained endogenous alpha-band networks, which in turn impaired task performance. Our findings also provide novel evidence for frequency-dependent exogenous modulation of cognition that is determined by the correspondence between the exogenous flicker frequency and the endogenous brain rhythms. SIGNIFICANCE STATEMENT Here we provide novel evidence that the interaction between exogenous rhythmic visual stimulation and endogenous brain rhythms can have frequency-specific behavioral effects. We show that alpha-band (10 Hz) flicker impairs stimulus

  6. Flicker study on variable speed wind turbines with doubly fed induction generators

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    to a conclusion that the factors mentioned above have different influences on flicker emission compared with that in the case of the fixed speed wind turbine. Flicker mitigation is realized by output reactive power control of the variable speed wind turbine with doubly fed induction generator. Simulation results...

  7. Dynamics of retinal vessel response to flicker light in glaucoma patients and ocular hypertensives.

    Science.gov (United States)

    Gugleta, K; Kochkorov, A; Waldmann, N; Polunina, A; Katamay, R; Flammer, J; Orgul, S

    2012-04-01

    To analyze dynamics of retinal vessel dilation response to flicker light in patients with glaucoma and ocular hypertension. Response to flicker light was measured in retinal vessels by means of Retinal Vessel Analyzer. After the baseline 50 seconds long diameter recording of inferior and superior temporal artery and vein, three flicker stimulations of 20 seconds duration was applied, with a 80 seconds break in between. Area under the curve of the vessel diameter (AUC) was compared during 3 flicker periods in the open angle glaucoma patients group (POAG, n = 47) and ocular hypertensives (OHT, n = 46) and age-matched healthy controls (n = 56) POAG eyes demonstrated smaller response of all vessels to flicker light in general than the other two groups (p = 0.0008), but the response dynamics was significantly different between the groups (p = 0.038), showing in three flicker periods a delayed increasing response in the POAG and OHT groups, and remaining stable in healthy subjects. General vessel response to flicker light was decreased in POAG patients despite the slow improvement in repeated flicker stimulation, indicating an altered response pattern.

  8. Flicker adaptation or superimposition raises the apparent spatial frequency of coarse test gratings.

    Science.gov (United States)

    Kaneko, Sae; Giaschi, Deborah; Anstis, Stuart

    2015-03-01

    Independent channels respond to both the spatial and temporal characteristics of visual stimuli. Gratings 3 cpd are sensed by sustained channels that prefer steady stimulation. From this we predict that adaptation to a spatially uniform flickering field will selectively adapt the transient channels and raise the apparent spatial frequency of coarse sinusoidal gratings. Observers adapted to a spatially uniform field whose upper or lower half was steady and whose other half was flickering. They then adjusted the spatial frequency of a stationary test (matching) grating on the previously unmodulated half field until it matched the apparent spatial frequency of a grating falling on the previously flickering half field. The adapting field flickered at 8 Hz and the spatial frequency of the gratings was varied in octave steps from 0.25 to 16 cpd. As predicted, adapting to flicker raised the apparent spatial frequency of the test gratings. The aftereffect reached a peak of 11% between 0.5 and 1 cpd and disappeared above 4 cpd. We also observed that superimposed 10 Hz luminance flicker raised the apparent spatial frequency of 0.5 cpd test gratings. The effect was not seen with slower flicker or finer test gratings. Altogether, our study suggests that apparent spatial frequency is determined by the balance between transient and sustained channels and that an imbalance between the channels caused by flicker can alter spatial frequency perception. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Flicker Adaptation of Low-Level Cortical Visual Neurons Contributes to Temporal Dilation

    Science.gov (United States)

    Ortega, Laura; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    Several seconds of adaptation to a flickered stimulus causes a subsequent brief static stimulus to appear longer in duration. Nonsensory factors, such as increased arousal and attention, have been thought to mediate this flicker-based temporal-dilation aftereffect. In this study, we provide evidence that adaptation of low-level cortical visual…

  10. Effects of cataracts on flicker electroretinograms recorded with RETeval™ system: new mydriasis-free ERG device.

    Science.gov (United States)

    Miura, Gen; Nakamura, Yosuke; Sato, Eiju; Yamamoto, Shuichi

    2016-03-05

    The purpose of this study was to evaluate the effects of cataracts on the flicker electroretinograms (ERGs) recorded with the RETeval™ system under mydriatic-free conditions. This was a retrospective study of 82 eyes of 60 patients with cataracts and 52 eyes of 38 patients who were pseudophakic. Flicker ERGs were recorded with the RETeval™ system (LKC Technologies, Gaithersburg, MD) under mydriatic-free condition with skin electrodes. Flicker ERGs were elicited by white light delivered at a frequency of 28.3 Hz and intensity of 8 Td-s. The implicit times and amplitudes of the ERGs recorded from the Grade 2 cataract, Grade 3 cataract, and pseudophakic groups were compared. The mean amplitude was significantly smaller in both cataract groups than the pseudophakic group (Grade 2 cataract vs pseudophakic group, P flicker ERGs. The presence of cataracts should be taken into consideration when interpreting the flicker ERG recorded with RETeval™.

  11. ''Flicker'' in small scale laser--plasma self-focusing

    International Nuclear Information System (INIS)

    Coggeshall, S.V.; Mead, W.C.; Jones, R.D.

    1988-01-01

    Small amplitude, short wavelength ion acoustic waves in laser-produced plasmas cause fluctuations in the trajectories of light rays that can lead to time-dependent, self-sustaining shifting of focal spots and a somewhat random redistribution of the light near the critical surface. This flickering is seen in simulations involving small scale beam inhomogeneities over a uniform background laser profile, which model the center of a realistic laser beam. The effect can cause significant intensity multiplication in long scale length high-Z plasmas with only modest beam imperfections

  12. How long depends on how fast--perceived flicker dilates subjective duration.

    Science.gov (United States)

    Herbst, Sophie K; Javadi, Amir Homayoun; van der Meer, Elke; Busch, Niko A

    2013-01-01

    How do humans perceive the passage of time and the duration of events without a dedicated sensory system for timing? Previous studies have demonstrated that when a stimulus changes over time, its duration is subjectively dilated, indicating that duration judgments are based on the number of changes within an interval. In this study, we tested predictions derived from three different accounts describing the relation between a changing stimulus and its subjective duration as either based on (1) the objective rate of changes of the stimulus, (2) the perceived saliency of the changes, or (3) the neural energy expended in processing the stimulus. We used visual stimuli flickering at different frequencies (4-166 Hz) to study how the number of changes affects subjective duration. To this end, we assessed the subjective duration of these stimuli and measured participants' behavioral flicker fusion threshold (the highest frequency perceived as flicker), as well as their threshold for a frequency-specific neural response to the flicker using EEG. We found that only consciously perceived flicker dilated perceived duration, such that a 2 s long stimulus flickering at 4 Hz was perceived as lasting as long as a 2.7 s steady stimulus. This effect was most pronounced at the slowest flicker frequencies, at which participants reported the most consistent flicker perception. Flicker frequencies higher than the flicker fusion threshold did not affect perceived duration at all, even if they evoked a significant frequency-specific neural response. In sum, our findings indicate that time perception in the peri-second range is driven by the subjective saliency of the stimulus' temporal features rather than the objective rate of stimulus changes or the neural response to the changes.

  13. How Long Depends on How Fast—Perceived Flicker Dilates Subjective Duration

    Science.gov (United States)

    Herbst, Sophie K.; Javadi, Amir Homayoun; van der Meer, Elke; Busch, Niko A.

    2013-01-01

    How do humans perceive the passage of time and the duration of events without a dedicated sensory system for timing? Previous studies have demonstrated that when a stimulus changes over time, its duration is subjectively dilated, indicating that duration judgments are based on the number of changes within an interval. In this study, we tested predictions derived from three different accounts describing the relation between a changing stimulus and its subjective duration as either based on (1) the objective rate of changes of the stimulus, (2) the perceived saliency of the changes, or (3) the neural energy expended in processing the stimulus. We used visual stimuli flickering at different frequencies (4–166 Hz) to study how the number of changes affects subjective duration. To this end, we assessed the subjective duration of these stimuli and measured participants' behavioral flicker fusion threshold (the highest frequency perceived as flicker), as well as their threshold for a frequency-specific neural response to the flicker using EEG. We found that only consciously perceived flicker dilated perceived duration, such that a 2 s long stimulus flickering at 4 Hz was perceived as lasting as long as a 2.7 s steady stimulus. This effect was most pronounced at the slowest flicker frequencies, at which participants reported the most consistent flicker perception. Flicker frequencies higher than the flicker fusion threshold did not affect perceived duration at all, even if they evoked a significant frequency-specific neural response. In sum, our findings indicate that time perception in the peri-second range is driven by the subjective saliency of the stimulus' temporal features rather than the objective rate of stimulus changes or the neural response to the changes. PMID:24194829

  14. Effects of flicker rate, complexity, and color combinations of Chinese characters and backgrounds on visual search performance with varying flicker types.

    Science.gov (United States)

    Huang, Kuo-Chen; Lin, Rung-Tai; Wu, Chih-Fu

    2011-08-01

    This study investigated the effects of number of strokes in Chinese characters, flicker rate, flicker type, and character/background color combination on search performance. 37 participants ages 14 to 18 years were randomly assigned to each flicker-type condition. The search field contained 36 characters arranged in a 6 x 6 matrix. Participants were asked to search for the target characters among the surrounding distractors and count how many target characters were displayed in the search array. Analysis indicated that the character/background color combination significantly affected search times. The color combinations of white/purple and white/green yielded search times greater than those for black/white and black/yellow combinations. A significant effect for flicker type on search time was also identified. Rotating characters facilitated search time, compared with twinkling ones. The number of strokes and the flicker rates also had positive effects on search performances. For flicker rate, the search accuracy for 0.5 Hz was greater than that for 1.0 Hz, and the latter was also greater than that for 2.0 Hz. Results are applicable to web advertisement designs containing dynamic characters, in terms of how to best capture readers' attention by various means of dynamic character presentation.

  15. Fluctuations of precipitated electron intensity in flickering auroral arcs

    International Nuclear Information System (INIS)

    Spiger, R.J.; Anderson, H.R.

    1985-01-01

    This paper reports on electron spectra associated with two aurorae observed by ground-based television. One auroral arc was observed to flicker, large variations in the precipitated electron energy occurring on a time scale of 114 ms. The major variations occur at the higher energies of the 0.5--20 keV range covered by the detectors. Changes in the particle flux occur primarily in the pitch angle range 0 0 to 60 0 . Analysis of the video data shows a larger variation in intensity along the lower border of the arc in keeping with the results of the electron spectra. The second arc was not observed to flicker, and the associated electron spectra and video data show no large variations in precipitated electron energy or video intensity modulation. While pitch angle distributions tend to be field-aligned in the first arc, the distributions in the second arc are nearly isotropic or peaked from 60 0 to 90 0 in the downward hemisphere

  16. Stochastic dynamics: Crossover from 1/f3 to flicker noise

    International Nuclear Information System (INIS)

    Canessa, E.; Nguyen, V.L.

    1993-01-01

    Finite time processes within the limits of the Newton equation and zero inertia motion (i.e., road to chaos) are studied by numerically solving the ordinary, stochastic Langevin equation in 1D for a free particle with inertial moving in a medium with viscosity γ. In this simulations, the scaling behaviour of particle trajectories χ(t) and velocities v(t) with time are derived and the inclusion of non-zero particle masses is shown to define the asymptotic time limit τ c at which - independently of γ - the system evolves into the well-known statistically stationary state characterized by 2 (t) > is proportional to t and flicker noise. The time τ c is further analysed from the correlation length given by the 2-point autocorrelation function of the particle velocity at each value of γ. It is found that the noise power spectrum of v(t) is characterized by flicker noise for frequencies f ≤ f c ∼ 1/τ c , whereas for f > f c , the noise power spectra behave as 1/f υ , where υ varies between the limits of Newton's equation (i.e., υ = 3) and road to chaos (i.e., υ = 1). Furthermore, at times τ c and 0 f (γ) while the single particle trajectories are shown to display a rather different subset of exponents on increasing γ. Generic features of this transition are nicely given by Poincare maps in the velocity space. (author). 23 refs, 8 figs

  17. FTIR Study of Comustion Species in Several Regions of a Candle Flame

    Science.gov (United States)

    White, Allen R.

    2013-06-01

    The complex chemical structure of the fuel in a candle flame, parafin, is broken down into smaller hydrocarbons in the dark region just above the candle wick during combustion. This creates fuel-rich, fuel-lean, hydrocarbon reaction, and combustion product regions in the flame during combustion that are spectroscopically rich, particularly in the infrared. IR emissions were measured for each reaction region via collection optics focused into an FTIR and used to identify IR active species present in that region and, when possible, temperature of the sampling region. The results of the measurements are useful for combustion reaction modeling as well as for future validation of mass spectroscopy sampling systems.

  18. The prevalence and severity of injuries in field hockey drag flickers: a retrospective cross-sectional study.

    Science.gov (United States)

    Ng, Leo; Sherry, Dorianne; Loh, Wei Bing; Sjurseth, Andreas Myhre; Iyengar, Shrikant; Wild, Catherine; Rosalie, Simon

    2016-09-01

    The drag flick is the preferred method of scoring during a penalty corner in field hockey. Performing the drag flick requires a combination of strength, coordination and timing, which may increase susceptibility to injuries. However, injury prevalence in drag flickers has not previously been investigated. Therefore, this study compared the injury prevalence and severity of lower limb and lower back injuries between drag flickers and non-drag flickers in field hockey. A total of 432 local, national and international adult field hockey players (242 males, 188 females) completed an online questionnaire to retrospectively determine the 3-month prevalence and severity of ankle, knee, hip and lower back injuries. Of this group, 140 self-identified as drag flickers and 292 as non-drag flickers. The results showed that drag flickers had significantly higher prevalence of hip (OR: 1.541; 95% CI: 1.014, 2.343) and lower back injury (OR: 1.564; 95% CI: 1.034, 2.365) compared to non-drag flickers. No significant differences were observed between drag flickers and non-drag flickers in injury prevalence at the ankle and knee. There were no significant between-group differences in injury severity scores. Overall, the prevalence of hip and lower back injuries was significantly higher in drag flickers compared to non-drag flickers.

  19. Retinal arteriolar dilation to flicker light is reduced on short-term retesting.

    Science.gov (United States)

    Noonan, Jonathan E; Nguyen, Thanh T; Man, Ryan E K; Best, William J; Wang, Jie Jin; Lamoureux, Ecosse L

    2013-11-21

    To investigate the impact of retesting frequency over a short period on flicker light-induced retinal vasodilation. Twenty healthy participants were included. The retinal vascular response to flicker light stimulation was assessed three times (at baseline and after 5 and 30 minutes of rest [tests 1, 2, and 3, respectively]) in each participant using the Dynamic Vessel Analyzer. Relative dilations of selected arteriole and venule segments during flicker stimulation and resting diameters were measured automatically. The mean vessel dilations and resting diameters were compared using repeated-measures analysis of variance. Participants were young (mean [SD] age, 33.1 [5.7] years) and mostly female (70%). The mean (SD) maximum arteriolar dilations during flicker stimulation were 3.23% (2.06%), 2.44% (1.62%), and 3.36% (2.11%) in tests 1, 2, and 3, respectively. The mean (SD) venular dilations were 4.26% (1.28%), 3.81% (1.61%), and 4.43% (1.73%) in tests 1, 2, and 3, respectively. The mean arteriolar dilations were significantly different across the three tests (P flicker stimulation is reduced on short-term retesting, without a significant change in baseline vessel diameter, indicating decreased responsiveness to the flicker stimulus. Researchers should allow at least 30 minutes between consecutive tests to minimize suppression of the flicker response.

  20. Response of inner retinal oxygen extraction fraction to light flicker under normoxia and hypoxia in rat.

    Science.gov (United States)

    Teng, Pang-yu; Wanek, Justin; Blair, Norman P; Shahidi, Mahnaz

    2014-09-02

    Oxygen extraction fraction (OEF), defined by the ratio of oxygen metabolism (MO2) to delivery (DO2), determines the level of compensation of MO2 by DO2. In the current study, we tested the hypothesis that inner retinal OEF remains unchanged during light flicker under systemic normoxia and hypoxia in rats due to the matching of MO2 and DO2. Retinal vascular oxygen tension (PO2) measurements were obtained in 10 rats by phosphorescence lifetime imaging. Inner retinal OEF was derived from vascular PO2 based on Fick's principle. Measurements were obtained before and during light flicker under systemic normoxia and hypoxia. The effects of light flicker and systemic oxygenation on retinal vascular PO2 and OEF were determined by ANOVA. During light flicker, retinal venous PO2 decreased (P flicker were similar under normoxia and hypoxia. During light flicker, OEF increased from 0.46 ± 0.13 to 0.50 ± 0.11 under normoxia, while under hypoxia, OEF increased from 0.67 ± 0.16 to 0.74 ± 0.14. Inner retinal OEF increased during light flicker, indicating the relative change in DO2 is less than that in MO2 in rats under systemic normoxia and hypoxia. Inner retinal OEF is a potentially useful parameter for assessment of the relative changes of MO2 and DO2 under physiologic and pathologic conditions. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  1. Insulin is a key determinant of elevated retinal arteriolar flicker response in insulin-resistant individuals.

    Science.gov (United States)

    Reimann, Manja; Vilser, Walthard; Gruber, Matthias; Bornstein, Stefan R; Ziemssen, Tjalf

    2015-09-01

    Insulin may link metabolic disorders to retinal microvascular pathology. The aim of the present study was to investigate the impact of early insulin resistance on retinal microcirculation. Retinal diameter responses to flicker-light stimulation were investigated in 81 clinically healthy participants (32 ± 6 years [mean ± SD], 59% women) who were recruited according to their BMI. All participants underwent an OGTT and euglycaemic-hyperinsulinaemic clamp (40 mU/m(2) · min(-1) insulin dose). After stratification by low and high insulin sensitivity based on a clamp-derived glucose disposal rate of ≤ or >4.9 mg/kg body mass, respectively, baseline retinal diameters and their relative changes to flicker stimulation were compared while controlling for mean arterial pressure, BMI and sex. The arterial vasodilator response at the end of flicker stimulation (p = 0.044) and the area under the arterial reaction curve during flicker stimulation (p = 0.015) were significantly higher in individuals with low vs high insulin sensitivity. Vasodilatory responses of retinal veins to flicker stimulation and baseline retinal diameters did not differ between insulin-sensitive and insulin-resistant participants (p > 0.05). In a stepwise linear regression analysis, fasting insulin remained the only predictor of the arterial vasodilator response to flicker-light (p flicker response in insulin-resistant states is a result of higher circulating insulin levels.

  2. Flicker light-induced retinal vasodilation in diabetes and diabetic retinopathy.

    Science.gov (United States)

    Nguyen, Thanh T; Kawasaki, Ryo; Wang, Jie Jin; Kreis, Andreas J; Shaw, Jonathan; Vilser, Walthard; Wong, Tien Y

    2009-11-01

    Flicker light-induced retinal vasodilation may reflect endothelial function in the retinal circulation. We investigated flicker light-induced vasodilation in individuals with diabetes and diabetic retinopathy. Participants consisted of 224 individuals with diabetes and 103 nondiabetic control subjects. Flicker light-induced retinal vasodilation (percentage increase over baseline diameter) was measured using the Dynamic Vessel Analyzer. Diabetic retinopathy was graded from retinal photographs. Mean +/- SD age was 56.5 +/- 11.8 years for those with diabetes and 48.0 +/- 16.3 years for control subjects. Mean arteriolar and venular dilation after flicker light stimulation were reduced in participants with diabetes compared with those in control subjects (1.43 +/- 2.10 vs. 3.46 +/- 2.36%, P flicker light-induced vasodilation were more likely to have diabetes (odds ratio 19.7 [95% CI 6.5-59.1], P flicker light-induced vasodilation were more likely to have diabetic retinopathy (2.2 [1.2-4.0], P = 0.01 for arteriolar dilation and 2.5 [1.3-4.5], P = 0.004 for venular dilation). Reduced retinal vasodilation after flicker light stimulation is independently associated with diabetes status and, in individuals with diabetes, with diabetic retinopathy. Our findings may therefore support endothelial dysfunction as a pathophysiological mechanism underlying diabetes and its microvascular manifestations.

  3. Role of flicker perimetry in predicting onset of late-stage age-related macular degeneration.

    Science.gov (United States)

    Luu, Chi D; Dimitrov, Peter N; Robman, Luba; Varsamidis, Mary; Makeyeva, Galina; Aung, Khin-Zaw; Vingrys, Algis J; Guymer, Robyn H

    2012-06-01

    To investigate the longitudinal changes in flicker perimetry in patients with age-related macular degeneration (AMD) as the condition progresses from early AMD to geographic atrophy (GA) or choroidal neovascularization (CNV). Patients with AMD and control subjects were recruited from a longitudinal study of retinal function in early AMD consisting of 187 participants. Only those who completed at least 4 consecutive, 6-monthly flicker perimetry tests were selected for this study. Study groups consisted of everyone who went on to develop GA (n = 16) or CNV (n = 5), controls (n = 24), and the high-risk, early- AMD participants whose eyes did not progress to GA or CNV (drusen >125 μm; n = 18). The flicker sensitivity was determined, and its rate of change during the 18 months before the clinical detection of late AMD was calculated. Eyes that went on to develop GA or CNV had a significantly reduced mean (SD) flicker sensitivity in the months before clinical detection of GA (15.8 [5.6] dB) or CNV (19.1 [3.8] dB) compared with control eyes (22.9 [3.0] dB) (P flicker sensitivity was significantly increased in GA eyes (-0.07 dB/mo) (P Flicker sensitivity is reduced in eyes that go on to develop late AMD. The rate of change in flicker sensitivities over time was particularly useful in predicting eyes and areas within the eye that subsequently develop GA.

  4. Inner Retinal Oxygen Extraction Fraction in Response to Light Flicker Stimulation in Humans.

    Science.gov (United States)

    Felder, Anthony E; Wanek, Justin; Blair, Norman P; Shahidi, Mahnaz

    2015-10-01

    Light flicker has been shown to stimulate retinal neural activity, increase blood flow, and alter inner retinal oxygen metabolism (MO2) and delivery (DO2). The purpose of the study was to determine the change in MO2 relative to DO2 due to light flicker stimulation in humans, as assessed by the inner retinal oxygen extraction fraction (OEF). An optical imaging system, based on a modified slit lamp biomicroscope, was developed for simultaneous measurements of retinal vascular diameter (D) and oxygen saturation (SO2). Retinal images were acquired in 20 healthy subjects before and during light flicker stimulation. Arterial and venous D (DA and DV) and SO2 (SO2A and SO2V) were quantified within a circumpapillary region. Oxygen extraction fraction was defined as the ratio of MO2 to DO2 and was calculated as (SO2A - SO2V)/SO2A. Reproducibility of measurements was assessed. Coefficients of variation and intraclass correlation coefficients of repeated measurements were flicker stimulation, DA, DV , and SO2V significantly increased (P ≤ 0.004). Oxygen extraction fraction was 0.37 ± 0.08 before light flicker and significantly decreased to 0.31 ± 0.07 during light flicker (P = 0.001). Oxygen extraction fraction before and during light flicker stimulation is reported in human subjects for the first time. Oxygen extraction fraction decreased during light flicker stimulation, indicating the change in DO2 exceeded that of MO2. This technology is potentially useful for the detection of changes in OEF response to light flicker in physiological and pathological retinal conditions.

  5. Inner Retinal Oxygen Extraction Fraction in Response to Light Flicker Stimulation in Humans

    Science.gov (United States)

    Felder, Anthony E.; Wanek, Justin; Blair, Norman P.; Shahidi, Mahnaz

    2015-01-01

    Purpose Light flicker has been shown to stimulate retinal neural activity, increase blood flow, and alter inner retinal oxygen metabolism (MO2) and delivery (DO2). The purpose of the study was to determine the change in MO2 relative to DO2 due to light flicker stimulation in humans, as assessed by the inner retinal oxygen extraction fraction (OEF). Methods An optical imaging system, based on a modified slit lamp biomicroscope, was developed for simultaneous measurements of retinal vascular diameter (D) and oxygen saturation (SO2). Retinal images were acquired in 20 healthy subjects before and during light flicker stimulation. Arterial and venous D (DA and DV) and SO2 (SO2A and SO2V) were quantified within a circumpapillary region. Oxygen extraction fraction was defined as the ratio of MO2 to DO2 and was calculated as (SO2A − SO2V)/SO2A. Reproducibility of measurements was assessed. Results Coefficients of variation and intraclass correlation coefficients of repeated measurements were <5% and ≥0.83, respectively. During light flicker stimulation, DA, DV , and SO2V significantly increased (P ≤ 0.004). Oxygen extraction fraction was 0.37 ± 0.08 before light flicker and significantly decreased to 0.31 ± 0.07 during light flicker (P = 0.001). Conclusions Oxygen extraction fraction before and during light flicker stimulation is reported in human subjects for the first time. Oxygen extraction fraction decreased during light flicker stimulation, indicating the change in DO2 exceeded that of MO2. This technology is potentially useful for the detection of changes in OEF response to light flicker in physiological and pathological retinal conditions. PMID:26469748

  6. Effect of regular smoking on flicker induced retinal vasodilatation in healthy subjects.

    Science.gov (United States)

    Garhöfer, Gerhard; Resch, Hemma; Sacu, Stefan; Weigert, Günther; Schmidl, Doreen; Lasta, Michael; Schmetterer, Leopold

    2011-11-01

    Habitual smoking is a risk factor for a variety of vascular diseases, including ocular pathologies. In the current study, we set out to investigate whether the regulation of retinal vascular tone is impaired in habitual smokers. For this purpose, vascular reactivity was tested during flicker light induced vasodilatation in smokers and in a non-smoking control group. In this prospective, balanced, parallel group study 24 chronic smokers (28.1 ± 3.3 years) and 24 age-matched never-smoking volunteers (28.2 ± 4.0 years) were included. Flicker induced vasodilatation was measured in major retinal arteries and veins using a retinal vessel analyzer and flicker induced changes in retinal blood velocities were assessed in retinal veins by laser Doppler velocimetry. Three flicker periods of 60s were scheduled. Blood cotinine concentration was determined and a Fagerstrom questionnaire was performed to evaluate nicotine dependency. In non-smoking subjects, stimulation with flicker light increased retinal venous diameter by +7.7 ± 3.1%, +6.9 ± 2.9% and +7.1 ± 2.8% during the three flicker periods, respectively. Flicker induced vasodilatation in veins was significantly diminished in chronic smokers (+4.9 ± 2.4%, +6.3 ± 3.1% and +5.7 ± 3.4%, ANOVA between groups, p=0.032) as compared to the non-smoking control group. Calculated retinal blood flow in the measured veins increased by a maximum of +54 ± 21%, +43 ± 18% and +46 ± 19% during the three stimulation periods in the non-smoking subjects, respectively. The flicker induced increase in retinal blood flow as assessed in the veins was significantly reduced in chronic smokers as compared to the non-smoking control group (+19 ± 16%, +26 ± 14%, +24 ± 13%, ANOVA between groups, p=0.013). In retinal arteries, flicker stimulation increased retinal arterial diameters by 5.2 ± 3.8%, 5.8 ± 4.8% and 5.5 ± 5.6% during the three flicker periods in the non-smoking group. In smokers, the flicker induced arterial vasodilatation

  7. Lung inflammation and genotoxicity in mice lungs after pulmonary exposure to candle light combustion particles

    DEFF Research Database (Denmark)

    Skovmand, Astrid; Damiao Gouveia, Ana Cecilia; Koponen, Ismo Kalevi

    2017-01-01

    Candle burning produces a large amount of particles that contribute substantially to the exposure to indoor particulate matter. The exposures to various types of combustion particles, such as diesel exhaust particles, have been associated with increased risk of lung cancer by mechanisms that invo...

  8. Burning a Candle in a Vessel, a Simple Experiment with a Long History

    Science.gov (United States)

    Vera, Francisco; Rivera, Rodrigo; Nunez, Cesar

    2011-01-01

    The experiment in which a candle is burned inside an inverted vessel partially immersed in water has a history of more than 2,200 years, but even nowadays it is common that students and teachers relate the change in volume of the enclosed air to its oxygen content. Contrary to what many people think, Lavoisier concluded that any change in volume…

  9. CANDLES - Search for Neutrino-less Double Beta Decay of 48Ca

    Science.gov (United States)

    Umehara, Saori; Candles Collaboration

    2014-09-01

    CANDLES is the project to search for neutrino-less double beta decay (0 νββ) of 48Ca. The CANDLES system aims at a high sensitive measurement by a characteristic detector system and 48Ca enrichment. The system realizes a complete 4 π active shield by immersing the CaF2 scintillators in liquid scintillator. The active shield by the liquid scintillator will effectively reject background events from external origins. On the other band, we have studied 48Ca enrichment and succeeded in obtaining enriched 48Ca although it is a small amount. Now we have developed the CANDLES III system, which contained 350 g of 48Ca without enrichment, at the Kamioka underground laboratory. Two improvements, a light-concentration system and a new DAQ system, were installed for the CANDLES III system. The light-concentration system improved a energy resolution by increasing a PMT photo-coverage by 80%. The new DAQ system, which is a dead time less system, improved a rejection efficiency for a characteristic background origin. We checked detector performance with the light-concentration system and the new DAQ system. Here we will report the detector performance for background rejection and the expected sensitivity with the two improvements.

  10. ''Flicker'' in laser-plasma self-focusing

    International Nuclear Information System (INIS)

    Coggeshall, S.V.; Mead, W.C.; Jones, R.D.

    1988-01-01

    Under certain conditions, a new mode of laser-plasma self-focusing can occur which is characterized by a self-sustaining, continual shifting of filament-produced focal spots and a somewhat chaotic redistribution of light at the critical surface. Associated with this phenomenon is the possibility of significant intensity multiplication due to self-focusing. This flickering of laser light is caused by small amplitude, short wavelength ion acoustic waves which are produced near the foci of the filaments and subsequently propagate and convect toward the laser. As these ion fluctuations move toward the laser, they cause further light ray trajectory changes which shift the locations of the foci. New sound waves are launched and the process is self-perpetuated. 7 refs., 5 figs

  11. Flickering of the symbiotic variable CH Cygni during outburst

    International Nuclear Information System (INIS)

    Slovak, M.H.; Africano, J.

    1978-01-01

    High-speed and conventional BVRI photometry are reported for the bright symbiotic variable CH Cygni (M6 IIIe), obtained during the course of a recent outburst. Unlike the quiescent symbiotic stars, the presence of flickering similar in nature to that seen in the cataclysmic variables has been confirmed during this active phase. The BVRI photometry for a sample of stars in the field is used to derive the reddening and the distance to CH Cyg. A composite energy distribution is derived from 0.35 to 11.0 μm which clearly establishes the existence of a variable, blue continuum. The lack of variability in the near infrared suggests that the blue continuum arises from a hot companion. A binary model including a subluminous hot companion accreting material from the stellar wind of an SRa variable is discussed to account for the observed photometric properties. (author)

  12. EJECTA KNOT FLICKERING, MASS ABLATION, AND FRAGMENTATION IN CASSIOPEIA A

    International Nuclear Information System (INIS)

    Fesen, Robert A.; Zastrow, Jordan A.; Hammell, Molly C.; Shull, J. Michael; Silvia, Devin W.

    2011-01-01

    Ejecta knot flickering, ablation tails, and fragmentation are expected signatures associated with the gradual dissolution of high-velocity supernova (SN) ejecta caused by their passage through an inhomogeneous circumstellar medium or interstellar medium (ISM). Such phenomena mark the initial stages of the gradual merger of SN ejecta with and the enrichment of the surrounding ISM. Here we report on an investigation of this process through changes in the optical flux and morphology of several high-velocity ejecta knots located in the outskirts of the young core-collapse SN remnant Cassiopeia A using Hubble Space Telescope images. Examination of WFPC2 F675W and combined ACS F625W + F775W images taken between 1999 June and 2004 December of several dozen debris fragments in the remnant's northeast ejecta stream and along the remnant's eastern limb reveal substantial emission variations ('flickering') over timescales as short as nine months. Such widespread and rapid variability indicates knot scale lengths ≅ 10 15 cm and a highly inhomogeneous surrounding medium. We also identify a small percentage of ejecta knots located all around the remnant's outer periphery which show trailing emissions typically 0.''2-0.''7 in length aligned along the knot's direction of motion suggestive of knot ablation tails. We discuss the nature of these trailing emissions as they pertain to ablation cooling, knot disruption, and fragmentation, and draw comparisons to the emission 'strings' seen in η Car. Finally, we identify several tight clusters of small ejecta knots which resemble models of shock-induced fragmentation of larger SN ejecta knots caused by a high-velocity interaction with a lower density ambient medium.

  13. Analysis of the Flicker Level Produced by a Fixed-Speed Wind Turbine

    Science.gov (United States)

    Suppioni, Vinicius; P. Grilo, Ahda

    2013-10-01

    In this article, the analysis of the flicker emission during continuous operation of a mid-scale fixed-speed wind turbine connected to a distribution system is presented. Flicker emission is investigated based on simulation results, and the dependence of flicker emission on short-circuit capacity, grid impedance angle, mean wind speed, and wind turbulence is analyzed. The simulations were conducted in different programs in order to provide a more realistic wind emulation and detailed model of mechanical and electrical components of the wind turbine. Such aim is accomplished by using FAST (Fatigue, Aerodynamics, Structures, and Turbulence) to simulate the mechanical parts of the wind turbine, Simulink/MatLab to simulate the electrical system, and TurbSim to obtain the wind model. The results show that, even for a small wind generator, the flicker level can limit the wind power capacity installed in a distribution system.

  14. Flicker Mitigation by Individual Pitch Control of Variable Speed Wind Turbines With DFIG

    DEFF Research Database (Denmark)

    Zhang, Yunqian; Chen, Zhe; Hu, Weihao

    2014-01-01

    Due to the wind speed variation, wind shear and tower shadow effects, grid connected wind turbines are the sources of power fluctuations which may produce flicker during continuous operation. This paper presents a model of an MW-level variable-speed wind turbine with a doubly fed induction...... generatorto investigate the flicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power...... and the azimuth angle of the wind turbine. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5-MW upwind reference wind turbine model. Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind...

  15. Relationship between Critical Flicker Fusion (CFF) Thresholds and Personality under Three Auditory Stimulus Conditions.

    Science.gov (United States)

    Ali, M. R.; Amir, T.

    1988-01-01

    Investigated relationship between critical flicker fusion (CFF) thresholds and five personality characteristics (alienation; social nonconformity; discomfort, expression, and defensiveness) under three auditory stimulus conditions (quiet, noise, meaningful verbal stimuli). Results from 60 college students revealed that auditory stimulation and…

  16. Time sequence analysis of flickering auroras. I - Application of Fourier analysis. [in atmosphere

    Science.gov (United States)

    Berkey, F. T.; Silevitch, M. B.; Parsons, N. R.

    1980-01-01

    Using a technique that enables one to digitize the brightness of auroral displays from individual fields of a video signal, we have analyzed the frequency content of flickering aurora. Through the application of Fourier analysis to our data, we have found that flickering aurora contains a wide range of enhanced frequencies, although the dominant frequency enhancement generally occurs in the range 6-12 Hz. Each incidence of flickering that we observed was associated with increased radio wave absorption. Furthermore, we have found that flickering occurs in bright auroral surges, the occurrence of which is not limited to the 'breakup' phase of auroral substorms. Our results are interpreted in terms of a recently proposed theory of fluctuating double layers that accounts for a number of the observational features.

  17. Converter controls and flicker study of PMSG-based grid connected wind turbines

    Directory of Open Access Journals (Sweden)

    Ali H. Kasem Alaboudy

    2013-03-01

    Full Text Available With the increased penetration of wind power, the influence of wind turbine generators on the grid power quality stipulates careful investigation and analysis. Direct driven permanent magnet synchronous generator (PMSG with a back-to-back converter set is one of the promising technologies in wind power generation schemes. In this paper, comprehensive models of wind turbine are used to analyze power and voltage fluctuations. The short time flicker index is used to assess the voltage fluctuation emitted. The control scheme of the grid-side converter is supported with a voltage regulation loop to reduce flicker emission. The effects of grid and site parameters on voltage fluctuation are investigated. Simulation results show that reduced flicker emissions are given when the developed voltage regulation loop is activated. Reasonable values of grid and site parameters contribute in the minimization of voltage fluctuation and flicker emission levels.

  18. Using electroretinograms to assess flicker fusion frequency in domestic hens Gallus gallus domesticus.

    Science.gov (United States)

    Lisney, Thomas J; Ekesten, Björn; Tauson, Ragnar; Håstad, Olle; Odeen, Anders

    2012-06-01

    The assessment of flicker fusion frequency (FFF), the stimulus frequency at which a flickering light stimulus can no longer be resolved and appears continuous, and critical flicker fusion frequency (CFF; the highest frequency at any light intensity that an observer can resolve flicker) are useful methods for comparing temporal resolution capabilities between animals. Behavioural experiments have found that average CFFs in domestic chickens (Gallus gallus domesticus) are in the range of ca. 75-87 Hz, measured in response to full spectrum (i.e. white light plus UV) stimuli. In order to examine whether the chicken retina is able to detect flicker at higher frequencies, we used electroretinograms (ERGs) to assess FFF/CFF in adult hens from two commercial genotypes, Lohmann Selected Leghorns (LSLs) and Lohmann Browns (LBs). ERGs were recorded in response to flickering light at ten full spectrum light intensities ranging from 0.7 to 2740 cd m(-2). Two methods were used to determine FFF/CFF from the ERG recordings and these methods yielded very similar results, with average FFF ranging from ca. 20Hz at 0.7 cd m(-2) to an average CFF of ca. 105 Hz at 2740 cd m(-2). In some individuals, CFFs of 118-119 Hz were recorded. The Intensity/FFF (I/FFF) curves are double-branched with a break point representing the rod-cone transition occurring between 2.5 and 5.9 cd m(-2). No significant differences in the I/FFF curves were found between the two genotypes. At stimulus light intensities >250 cd m(-2), the ERG-derived FFF and CFF values are all higher than those from behavioural studies using the same stimuli. Although hens do not appear to be able to consciously perceive flicker above approximately 90 Hz, the finding that the ERG responses are able to remain in phase with light flickering at frequencies >100 Hz means that the retinae of domestic poultry housed in artificial light conditions may be able to resolve flicker from fluorescent lamps. As range of detrimental effects have

  19. Flicker Noise in GNSS Station Position Time Series: How much is due to Crustal Loading Deformations?

    Science.gov (United States)

    Rebischung, P.; Chanard, K.; Metivier, L.; Altamimi, Z.

    2017-12-01

    The presence of colored noise in GNSS station position time series was detected 20 years ago. It has been shown since then that the background spectrum of non-linear GNSS station position residuals closely follows a power-law process (known as flicker noise, 1/f noise or pink noise), with some white noise taking over at the highest frequencies. However, the origin of the flicker noise present in GNSS station position time series is still unclear. Flicker noise is often described as intrinsic to the GNSS system, i.e. due to errors in the GNSS observations or in their modeling, but no such error source has been identified so far that could explain the level of observed flicker noise, nor its spatial correlation.We investigate another possible contributor to the observed flicker noise, namely real crustal displacements driven by surface mass transports, i.e. non-tidal loading deformations. This study is motivated by the presence of power-law noise in the time series of low-degree (≤ 40) and low-order (≤ 12) Stokes coefficients observed by GRACE - power-law noise might also exist at higher degrees and orders, but obscured by GRACE observational noise. By comparing GNSS station position time series with loading deformation time series derived from GRACE gravity fields, both with their periodic components removed, we therefore assess whether GNSS and GRACE both plausibly observe the same flicker behavior of surface mass transports / loading deformations. Taking into account GRACE observability limitations, we also quantify the amount of flicker noise in GNSS station position time series that could be explained by such flicker loading deformations.

  20. Impaired increase of retinal capillary blood flow to flicker light exposure in arterial hypertension.

    Science.gov (United States)

    Ritt, Martin; Harazny, Joanna M; Ott, Christian; Raff, Ulrike; Bauernschubert, Philipp; Lehmann, Marina; Michelson, Georg; Schmieder, Roland E

    2012-09-01

    We hypothesized that the increase of retinal capillary blood flow (RCF) to flicker light exposure is impaired in subjects with arterial hypertension. In 146 nondiabetic untreated male subjects with (n=50) or without (n=96) arterial hypertension, RCF was measured before and after flicker light exposure noninvasively and in vivo using scanning laser Doppler flowmetry. In addition, in a subgroup of 28 subjects, the change of RCF to flicker light exposure was again assessed during parallel infusion of nitric oxide synthase inhibitor N-monomethyl-L-arginine (L-NMMA). The increase of RCF to flicker light exposure was lower in patients with untreated hypertension compared with normotensive subjects when expressed in absolute terms (7.69±54 versus 27.2±44 AU; P adjusted=0.013) or percent changes (2.95±14 versus 8.33±12%; P adjusted=0.023). Systolic (β=-0.216; P=0.023) but not diastolic blood pressure (β=-0.117; P=0.243) or mean arterial pressure (β=-0.178; P=0.073) was negatively related to the percent change of RCF to flicker light exposure, independently of other cardiovascular risk factors. In the subgroup of 28 subjects, the increase of RCF to flicker light exposure was similar at baseline and during parallel infusion of L-NMMA when expressed in absolute terms (20.0±51 versus 22.6±56 AU; P=0.731) or percent changes (7.12±16 versus 8.29±18%; P=0.607). The increase of RCF to flicker light exposure is impaired in arterial hypertension. In the subgroup of the total study cohort, nitric oxide was not a major determinant of the increase of RCF to flicker light exposure.

  1. A Linearized Model for Flicker and Contrast Thresholds at Various Retinal Illuminances

    Science.gov (United States)

    Ahumada, Albert; Watson, Andrew

    2015-01-01

    We previously proposed a flicker visibility metric for bright displays, based on psychophysical data collected at a high mean luminance. Here we extend the metric to other mean luminances. This extension relies on a linear relation between log sensitivity and critical fusion frequency, and a linear relation between critical fusion frequency and log retina lilluminance. Consistent with our previous metric, the extended flicker visibility metric is measured in just-noticeable differences (JNDs).

  2. Abnormal retinal vascular oxygen tension response to light flicker in diabetic rats.

    Science.gov (United States)

    Blair, Norman P; Wanek, Justin M; Mori, Marek; Shahidi, Mahnaz

    2009-11-01

    To test the hypothesis that the intravascular oxygen response to light flicker is abnormal in diabetes. Ten eyes of normal rats and 10 eyes of rats made diabetic with streptozotocin were examined. Oxygen tension (PO(2)) was measured noninvasively in the retinal arteries and veins on optical section retinal images. PO(2) was estimated based on the quenching by oxygen of the phosphorescence of an intravenously injected palladium porphyrin molecular probe. Measurements were conducted with and without light flicker at 10 Hz. Oxygen saturation (SO(2)) was calculated with adjustment for the arterial pH. In the normal rats flicker induced an increase in arterial PO(2) and in the difference in arterial and venous (A-V difference) PO(2) from 51 +/- 5 (mean and SD) to 55 +/- 7 mm Hg and from 22 +/- 3 to 26 +/- 5 mm Hg, respectively (P Flicker induced an increase of arterial SO(2) and A-V SO(2) difference from 64% +/- 8% to 68% +/- 7% and from 34% +/- 4% to 38% +/- 6%, respectively (P flicker in the veins. In the diabetic rats, no significant flicker-induced changes were seen in PO(2) or SO(2) in the retinal arteries, veins, or A-V differences. The diabetic rats lacked the flicker induced increase in arterial PO(2) and SO(2) and also the A-V difference in PO(2) and SO(2) observed in the normal rats. The best explanation appeared to be that diabetes impairs the increase in oxygen consumption normally provoked by light flicker.

  3. Residues in common flicker and mountain bluebird eggs one year after a DDT application

    Science.gov (United States)

    Henny, C.J.; Olson, R.A.; Meeker, D.L.

    1977-01-01

    Common flicker (Colaptes auratus) and mountain bluebird (Sialia currucoides) eggs were examined 1 year after DDT application and showed a marked difference. Residue levels in mountain bluebird eggs were approximately 10 times higher than in common flicker eggs (5.29 to 0.58 ppm wet weight). These differences can be explained by disparate dietary habits. The mean level in American kestrel (Falco sparverius) eggs collected in the spray area at the same time was 6.42 ppm wet weight.

  4. Flicker-defined form stimuli are minimally affected by centre-surround lateral contrast interactions

    OpenAIRE

    Denniss, Jonathan; McKendrick, Allison M.

    2016-01-01

    Purpose: Flicker-defined form (FDF) stimuli have recently been adopted for visual field testing. A key difference between FDF and traditional perimetric stimuli is that the entire display background contains flickering dots. The purpose of this study was to determine whether the perception of FDF stimuli is influenced by lateral interactions involving regions beyond the stimulus border in young healthy observers.\\ud \\ud Methods: Experiment 1 measured the effect of surround size and retinal ec...

  5. First evidence of patchy flickering aurora modulated by multi-ion electromagnetic ion cyclotron waves

    Science.gov (United States)

    Fukuda, Yoko; Kataoka, Ryuho; Uchida, Herbert Akihito; Miyoshi, Yoshizumi; Hampton, Donald; Shiokawa, Kazuo; Ebihara, Yusuke; Whiter, Daniel; Iwagami, Naomoto; Seki, Kanako

    2017-05-01

    Electromagnetic ion cyclotron (EMIC) waves, one of the possible origins of flickering aurora, have been thought to modulate the electron flux at a few thousand kilometers. In fact, flickering aurora with a frequency range of 3-15 Hz has often been identified by ground-based optical observations and has been interpreted to be caused by O+-band EMIC waves. However, extant research to date has not identified possible signatures of H+-band EMIC waves due to technical limitations of ground-based high-speed imagers. The present study shows the first evidence that patchy flickering aurora could be modulated by H+-band EMIC waves, based on the data obtained from imaging observations at 160 frames per second. The sporadic appearance of the flickering aurora in the frequency range of 50-80 Hz coexisted with typical flickering auroras of approximately 10 Hz. These results are consistent with the hypothesis that flickering auroras are generated by multi-ion EMIC waves.

  6. Improved control system of the thyristor flicker suppressor for the KEK 12-GeV PS

    International Nuclear Information System (INIS)

    Matsumoto, S.; Baba, H.; Mikawa, K.; Sato, H.; Sueno, T.

    1983-01-01

    Thyristor control system of the 20 MVar flicker suppressor has been improved essentially. The previous feed forward (FF) loop with each single phase reactive current detector of the MR magnet power supply was exchanged to the present by both FF- and NFB-loops. The FF-loops consists of a three phase reactive power detector of the MPS and a forcing pattern generator on the fast but steady line voltage flicker, sag and surge. The NFB-loops control by the slow parts of the flicker and the unbalanced line voltages. These detectors of the reactive power, the voltage flicker and the unbalance have been developed. Sampled voltage flicker data with 12 bit ADC are processed by Z-80A micro computer system and the forcing pattern is generated by the system through 12 bit DAC into the loop. A typical voltage flicker including sag and surge has been reduced within + or - 1.5%, about 1/3 compared to the previous, at 66 kV primary line

  7. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  8. 76 FR 46277 - Petroleum Wax Candles From the People's Republic of China: Final Results of Request for Comments...

    Science.gov (United States)

    2011-08-02

    ... solicited comments from interested parties on the best method to consider whether novelty candles should or..., LLC, and Accent Imports, respectively, for scope rulings to determine whether each company's...

  9. What has driven the evolution of multiple cone classes in visual systems: object contrast enhancement or light flicker elimination?

    Science.gov (United States)

    Sabbah, Shai; Hawryshyn, Craig W

    2013-07-04

    Two competing theories have been advanced to explain the evolution of multiple cone classes in vertebrate eyes. These two theories have important, but different, implications for our understanding of the design and tuning of vertebrate visual systems. The 'contrast theory' proposes that multiple cone classes evolved in shallow-water fish to maximize the visual contrast of objects against diverse backgrounds. The competing 'flicker theory' states that multiple cone classes evolved to eliminate the light flicker inherent in shallow-water environments through antagonistic neural interactions, thereby enhancing object detection. However, the selective pressures that have driven the evolution of multiple cone classes remain largely obscure. We show that two critical assumptions of the flicker theory are violated. We found that the amplitude and temporal frequency of flicker vary over the visible spectrum, precluding its cancellation by simple antagonistic interactions between the output signals of cones. Moreover, we found that the temporal frequency of flicker matches the frequency where sensitivity is maximal in a wide range of fish taxa, suggesting that the flicker may actually enhance the detection of objects. Finally, using modeling of the chromatic contrast between fish pattern and background under flickering illumination, we found that the spectral sensitivity of cones in a cichlid focal species is optimally tuned to maximize the visual contrast between fish pattern and background, instead of to produce a flicker-free visual signal. The violation of its two critical assumptions substantially undermines support for the flicker theory as originally formulated. While this alone does not support the contrast theory, comparison of the contrast and flicker theories revealed that the visual system of our focal species was tuned as predicted by the contrast theory rather than by the flicker theory (or by some combination of the two). Thus, these findings challenge key

  10. The Effects of Diabetic Retinopathy Stage and Light Flicker on Inner Retinal Oxygen Extraction Fraction.

    Science.gov (United States)

    Felder, Anthony E; Wanek, Justin; Blair, Norman P; Joslin, Charlotte E; Brewer, Katherine C; Chau, Felix Y; Lim, Jennifer I; Leiderman, Yannek I; Shahidi, Mahnaz

    2016-10-01

    We determined the effects of light flicker and diabetic retinopathy (DR) stage on retinal vascular diameter (D), oxygen saturation (SO2), and inner retinal oxygen extraction fraction (OEF). Subjects were categorized as nondiabetic control (NC, n = 42), diabetic with no clinical DR (NDR; n = 32), nonproliferative DR (NPDR; n = 42), or proliferative DR (PDR; n = 14). Our customized optical imaging system simultaneously measured arterial and venous D (DA, DV) and SO2 (SO2A, SO2V) before and during light flicker. Inner retinal OEF was derived from SO2 values. Light flicker-induced ratios of metrics (DAR, DVR, SO2AR, SO2VR, OEFR) were calculated. Arterial D was larger in NPDR compared to NC (P = 0.01) and PDR (P = 0.002), whereas DV was similar among groups (P ≥ 0.16). Light flicker increased DA and DV (P ≤ 0.004), but DAR and DVR were similar among groups (P ≥ 0.09). Arterial SO2 was higher in all groups compared to NC (P ≤ 0.02) and higher in PDR compared to NDR and NPDR (Pflicker (P ≥ 0.1). Venous SO2 was higher in NPDR and PDR compared to NC and NDR (P ≤ 0.02). Light flicker increased SO2V in NC, NDR, and PDR (P ≤ 0.003), and SO2VR was lower in NPDR compared to NC and NDR (P ≤ 0.05). Inner retinal OEF was lower in NPDR compared to NDR and PDR (P ≤ 0.02). Light flicker decreased OEF (P ≤ 0.03), but OEFR was greater in NPDR compared to NC and NDR (P ≤ 0.03). The findings of alterations in retinal D, SO2, OEF, and their light flicker-induced responses at stages of DR may be useful to elucidate the pathophysiology of DR.

  11. Constant luminance (cd·s/m2) versus constant retinal illuminance (Td·s) stimulation in flicker ERGs.

    Science.gov (United States)

    Davis, C Quentin; Kraszewska, Olga; Manning, Colette

    2017-04-01

    To compare the effect of variable pupil size on the flicker electroretinogram (ERG) between a stimulus having constant luminance and a stimulus having constant retinal illuminance (constant Troland) that compensates for pupil size. Subjects (n = 18) were tested with 12 pairs of the stimuli. The stimulus pair consisted of the ISCEV standard constant luminance stimulus (3 cd·s/m 2 with a 30 cd/m 2 background) and a constant retinal illuminance stimulus (32 Td·s with a 320 Td background) selected to provide the same stimulus and background when the pupil diameter is 3.7 mm. Half the subjects were artificially dilated, and their response was measured before and during the dilation. The natural pupil group was used to assess intra- and inter-subject variability. The artificially dilated group was used to measure the flicker ERG's dependence on pupil size. With natural pupils, intra-subject variability was lower with the constant Troland stimulus, while inter-subject variability was similar between stimuli. During pupil dilation, the constant Troland stimulus did not have a dependence on pupil size up to 6.3 mm and had slightly larger amplitudes with longer implicit times for fully dilated pupils. For the constant luminance stimulus, waveform amplitudes varied by 22% per mm change in pupil diameter, or by 48% over the 2.2 mm diameter range measured in dilated pupil size. There was no difference in inter-subject variability between constant Troland natural pupils and the same subjects with a constant luminance stimulus when dilated (i.e., the ISCEV standard condition). These results suggest that a constant Troland flicker ERG test with natural pupils may be advantageous in clinical testing. Because of its insensitivity to pupil size, constant Troland stimuli should produce smaller reference ranges, which in turn should improve the sensitivity for detection of abnormalities and for monitoring changes. In addition, the test can be administered more efficiently as

  12. Flicker-noise fluctuations in α-radioactive decay

    International Nuclear Information System (INIS)

    Kousik, G.S.; Gong, J.; Vanvliet, C.M.; Bosman, G.; Ellis, W.H.; Carroll, E.E.; Handel, P.H.

    1987-01-01

    Counting statistics of α particles from three sources, one containing 241 Am; one containing 239 Pu, 241 Am, and 244 Cu; and a source containing 148 Gd, were determined over periods of 1-4000 min. In particular, the two-sample variance or Allan variance was determined for many sample runs. According to a recent theorem, there is a unique relation between the particle-flux spectral noise density and the Allan variance. It was found that for small counting periods, the statistics were Poissonian, corresponding to shot noise of the particle flux. For long periods (> ≅ 200 min), the counting statistics were found to be non-Poissonian, indicating the presence of 1/f noise and (or) Lorentzian noise. The 1/f noise gave flicker floors of (0.5-0.7) x 10 -7 for 239 Pu, (1.0-1.3) x 10 -7 for 241 Am, and 3.0 x 10 -7 for 244 Cm. The Lorentzians were not reproducible in different runs and are probably associated with chemical oxidation-reduction rate processes in the source. The 1/f noise is likely inherent in the process of α-particle decay, indicating that the classical picture of alpha decay as a Poisson process is incomplete. Some forms of quantum 1/f noise associated with the tunnel-emission process are briefly discussed

  13. Critical flicker frequency is diagnostic of minimal hepatic encephalopathy.

    Science.gov (United States)

    Esmat, Serag; Garem, Nouman El; Raslan, Hassan; Elfekki, Mohamed; Sleem, Gihan A

    2017-12-01

    Minimal hepatic encephalopathy may affect up to 80% of cirrhotic patients, in the absence of overt hepatic encephalopathy. The objective of the study is to evaluate the accuracy of diagnosis of minimal hepatic encephalopathy with critical flicker frequency (CFF). The study was conducted on 180 patients with post hepatitis C liver cirrhosis and on 60 healthy subjects as control. Patients and controls were divided into four groups: group 1 (60), healthy individuals as a control group; group 2 (60), patients with liver cirrhosis (Child class A); group 3 (60), patients with liver cirrhosis (Child class B); and group 4 (60), patients with liver cirrhosis (Child class C). All participants were subjected to estimation of CFF, line drawing test, complete blood picture, liver functions, viral markers, and abdominal ultrasound. CFF detected abnormality in 90% of patients. Accuracy of CFF in differentiation of Child A from normal is 100%, Child B from normal is 100%, Child C from normal is 100%, Child A from Child B is 80%, Child A from Child C is 100% and Child B from Child C is 100%, and it has higher accuracy than line drawing test. CFF is a simple, reliable and accurate method for the diagnosis of minimal hepatic encephalopathy. It is not influenced by the patient level of education. © American Federation for Medical Research (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. Flicker downregulates the content of crystallin proteins in form-deprived C57BL/6 mouse retina.

    Science.gov (United States)

    Li, Saiqun; Wu, Junshu; Ding, Hui; Liao, Aiping; He, Hong; Stell, William K; Zhong, Xingwu

    2012-08-01

    Image degradation by loss of higher spatial frequencies causes form-deprivation myopia (FDM) in humans and animals, and cyclical illumination (flicker) at certain frequencies may prevent FDM. The molecular mechanisms underlying FDM and its prevention by flicker are poorly known. To understand them better, we have identified proteins that differ in amount in form-deprived (FD) mouse retinas, under steady versus flickering light. Male C57BL/6 mice (age 27-29 days) were randomly divided into three groups: Experimental - monocularly form-deprived, and kept under either normal room light ("FD-Only") or 20 Hz flickering light ("FD-Flicker"), throughout the 12-hour light phase; and Control ("Open-Control") - kept under normal illumination, without form deprivation. After two weeks of treatment, retinal proteins were extracted and separated by two-dimensional gel electrophoresis (2D-GE); proteins that differ in content in FD-only versus FD-flicker retinas were identified by mass spectroscopy ("MS"), and their identities were verified by western blotting. The contents of three identified proteins differed statistically in FD-only compared to FD-flicker retinas. These proteins were identified by MS as α-A-crystallin, crystallin β A2 and crystallin β A1. Quantitative western blotting showed that the relative amount of α-A-crystallin in FD-only retinas was significantly higher than that in FD-Flicker and control retinas. In conclusion, form deprivation induced significant increases in the amounts of crystallins in mouse retinas. These increases were significantly reduced by exposure to 20 Hz flicker. Since form deprivation is known to induce myopia development, and flicker to prevent it, our data suggest that FD- and flicker-responsive changes in the content of crystallin proteins may be involved causally or protectively in myopia development. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Investigation of Reactive Power Control Effects on Flicker and Harmonics Emission of a DFIG Wind Turbine

    Directory of Open Access Journals (Sweden)

    Amir Nagizadeh Ghoogdareh

    2013-01-01

    Full Text Available One of the most important power quality aspects in wind farms is voltage fluctuation or flicker which should be investigated due to the nature of wind speed variations. These variations result in power and voltage fluctuations at the load bus. Moreover, the wind generation systems may be assumed as a harmonics source because of their power electronic converters. There are numerous factors that affect flicker and harmonic emission of grid-connected wind turbines during continuous operation, such as wind characteristics (e.g. mean wind speed, turbulence intensity, type of generator and grid conditions (e.g. short circuit capacity, grid impedance angle. In this paper, an IEC based flickermeter is first modeled and then a variable speed wind turbine has been simulated by Matlab/Simulink software. The flicker and harmonics emissions of wind turbines equipped with DFIG during continuous operation and using output reactive control are investigated. The simulation results show that control of wind turbine output reactive power is an effective means for flicker mitigation during continuous operation. However, there should be a compromise between flicker reduction and harmonics level increase to enhance the whole power quality of wind turbine.

  16. Flicker electroretinograms before and after intravitreal ranibizumab injection in eyes with central retinal vein occlusion.

    Science.gov (United States)

    Yasuda, Shunsuke; Kachi, Shu; Ueno, Shinji; Piao, Chang-Hua; Terasaki, Hiroko

    2015-09-01

    To compare the amplitudes and implicit times of the flicker electroretinograms before and after an intravitreal injection of ranibizumab (IVR) in eyes with a central retinal vein occlusion (CRVO). We reviewed the medical records of 15 consecutive patients who had macular oedema secondary to CRVO and had received an IVR at the Nagoya University Hospital from November 2013 to July 2014. Flicker ERGs were recorded with both the RETeval(™) system and a conventional ERG system before the IVR. One month after the IVR, recordings were repeated with only the RETeval(™) system. The mean implicit times of the flicker ERGs of the affected eyes recorded with the RETeval(™) system were significantly longer than that of the fellow eyes (32.2 ± 2.6 msec versus 28.1 ± 1.2 msec, p flicker ERGs of affected eyes were significantly shortened from 32.2 ± 2.6 to 30.6 ± 2.2 msec (p flicker ERGs after the IVR indicates an improvement of retinal function after anti-VEGF therapy for CRVO eyes. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  17. Defining phosphor luminescence property requirements for white AC LED flicker reduction

    International Nuclear Information System (INIS)

    Tan, Jianchuan; Narendran, Nadarajah

    2015-01-01

    In this paper, we investigate the luminescence of slow-decay phosphors under flickering excitation from an alternating current light-emitting diode (AC LED). A mathematical model was developed to predict the behavior of slow-decay phosphors. The model predictions were validated by experiment. Results showed that it is possible to achieve good quality white light with low flicker index from an AC LED with a slow-decay phosphor. A human factors study confirmed the potential of slow-decay phosphors to improve acceptability of the light output from AC LEDs. Based on this study, we propose a set of recommendations for slow-decay phosphor luminescence properties to create a white AC LED with minimal flicker. - Highlights: • A mathematical model was proposed to simulate slow-decay phosphors. • The behavior of slow-decay phosphors under an AC LED excitation was simulated. • Slow-decay phosphor properties recommended to achieve low flicker, white AC LED. • A human factors study validated the flicker reduction by slow-decay phosphor

  18. Temporal presentation protocols in stereoscopic displays: Flicker visibility, perceived motion, and perceived depth

    Science.gov (United States)

    Hoffman, David M.; Karasev, Vasiliy I.; Banks, Martin S.

    2011-01-01

    Most stereoscopic displays rely on field-sequential presentation to present different images to the left and right eyes. With sequential presentation, images are delivered to each eye in alternation with dark intervals, and each eye receives its images in counter phase with the other eye. This type of presentation can exacerbate image artifacts including flicker, and the appearance of unsmooth motion. To address the flicker problem, some methods repeat images multiple times before updating to new ones. This greatly reduces flicker visibility, but makes motion appear less smooth. This paper describes an investigation of how different presentation methods affect the visibility of flicker, motion artifacts, and distortions in perceived depth. It begins with an examination of these methods in the spatio-temporal frequency domain. From this examination, it describes a series of predictions for how presentation rate, object speed, simultaneity of image delivery to the two eyes, and other properties ought to affect flicker, motion artifacts, and depth distortions, and reports a series of experiments that tested these predictions. The results confirmed essentially all of the predictions. The paper concludes with a summary and series of recommendations for the best approach to minimize these undesirable effects. PMID:21572544

  19. Use of high-frequency visual stimuli above the critical flicker frequency in a SSVEP-based BMI.

    Science.gov (United States)

    Sakurada, Takeshi; Kawase, Toshihiro; Komatsu, Tomoaki; Kansaku, Kenji

    2015-10-01

    This study presents a new steady-state visual evoked potential (SSVEP)-based brain-machine interface (BMI) using flickering visual stimuli at frequencies greater than the critical flicker frequency (CFF). We first asked participants to fixate on a green/blue flicker (30-70Hz), and SSVEP amplitude was evaluated. Participants were asked to indicate whether the stimulus was visibly flickering and to report their subjective level of discomfort. We then assessed visibly (41, 43, and 45Hz) vs. invisibly (61, 63, and 65Hz) flickering stimulus in an SSVEP-based BMI. Visual fatigue was assessed via the flicker test before and after operation of the BMI. Higher frequency stimuli reduced participants' subjective discomfort. Participants successfully controlled the SSVEP-based BMI using both the visibly and invisibly flickering stimuli (93.1% and 88.0%, respectively); the flicker test revealed a decrease in CFF (i.e., visual fatigue) under the visible condition only (-5.7%, Pflicker stimuli above the CFF were able to induce SSVEPs and may prove useful in the development of BMI-based assistive products. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  20. A model for the origin and properties of flicker-induced geometric phosphenes.

    Directory of Open Access Journals (Sweden)

    Michael Rule

    2011-09-01

    Full Text Available We present a model for flicker phosphenes, the spontaneous appearance of geometric patterns in the visual field when a subject is exposed to diffuse flickering light. We suggest that the phenomenon results from interaction of cortical lateral inhibition with resonant periodic stimuli. We find that the best temporal frequency for eliciting phosphenes is a multiple of intrinsic (damped oscillatory rhythms in the cortex. We show how both the quantitative and qualitative aspects of the patterns change with frequency of stimulation and provide an explanation for these differences. We use Floquet theory combined with the theory of pattern formation to derive the parameter regimes where the phosphenes occur. We use symmetric bifurcation theory to show why low frequency flicker should produce hexagonal patterns while high frequency produces pinwheels, targets, and spirals.

  1. Flicker Noise as a Probe of Electronic Interaction at Metal-Single Molecule Interfaces.

    Science.gov (United States)

    Adak, Olgun; Rosenthal, Ethan; Meisner, Jeffery; Andrade, Erick F; Pasupathy, Abhay N; Nuckolls, Colin; Hybertsen, Mark S; Venkataraman, Latha

    2015-06-10

    Charge transport properties of metal-molecule interfaces depend strongly on the character of molecule-electrode interactions. Although through-bond coupled systems have attracted the most attention, through-space coupling is important in molecular systems when, for example, through-bond coupling is suppressed due to quantum interference effects. To date, a probe that clearly distinguishes these two types of coupling has not yet been demonstrated. Here, we investigate the origin of flicker noise in single molecule junctions and demonstrate how the character of the molecule-electrode coupling influences the flicker noise behavior of single molecule junctions. Importantly, we find that flicker noise shows a power law dependence on conductance in all junctions studied with an exponent that can distinguish through-space and through-bond coupling. Our results provide a new and powerful tool for probing and understanding coupling at the metal-molecule interface.

  2. Screening for diabetic retinopathy using new mydriasis-free, full-field flicker ERG recording device

    Science.gov (United States)

    Fukuo, Motonobu; Kondo, Mineo; Hirose, Akira; Fukushima, Harumi; Ikesugi, Kengo; Sugimoto, Masahiko; Kato, Kumiko; Uchigata, Yasuko; Kitano, Shigehiko

    2016-01-01

    Diabetic retinopathy (DR) is a leading cause of blindness among working-age adults. Therefore, it is important to detect DR accurately during mass screening. The purpose of this study was to determine whether a small, hand-held, mydriasis-free, full-field flicker electroretinographic (ERGs) device called RETeval can be used to screen for DR. To accomplish this, we recorded full-field flicker ERGs with this device from 48 normal eyes and 118 eyes with different severities of DR in patients with diabetes mellitus (DM). This system delivered a constant flash retinal luminance by adjusting the flash luminance that compensated for changes in the pupil size. Our results showed that there were significant correlations between the severity of DR and the implicit times (P flicker ERGs recorded by the small, mydryasis-free ERG system can be used as an adjunctive tool to screen for DR. PMID:27824158

  3. Monocular and binocular steady-state flicker VEPs: frequency-response functions to sinusoidal and square-wave luminance modulation.

    Science.gov (United States)

    Nicol, David S; Hamilton, Ruth; Shahani, Uma; McCulloch, Daphne L

    2011-02-01

    Steady-state VEPs to full-field flicker (FFF) using sinusoidally modulated light were compared with those elicited by square-wave modulated light across a wide range of stimulus frequencies with monocular and binocular FFF stimulation. Binocular and monocular VEPs were elicited in 12 adult volunteers to FFF with two modes of temporal modulation: sinusoidal or square-wave (abrupt onset and offset, 50% duty cycle) at ten temporal frequencies ranging from 2.83 to 58.8 Hz. All stimuli had a mean luminance of 100 cd/m(2) with an 80% modulation depth (20-180 cd/m(2)). Response magnitudes at the stimulus frequency (F1) and at the double and triple harmonics (F2 and F3) were compared. For both sinusoidal and square-wave flicker, the FFF-VEP magnitudes at F1 were maximal for 7.52 Hz flicker. F2 was maximal for 5.29 Hz flicker, and F3 magnitudes are largest for flicker stimulation from 3.75 to 7.52 Hz. Square-wave flicker produced significantly larger F1 and F2 magnitudes for slow flicker rates (up to 5.29 Hz for F1; at 2.83 and 3.75 Hz for F2). The F3 magnitudes were larger overall for square-wave flicker. Binocular FFF-VEP magnitudes are larger than those of monocular FFF-VEPs, and the amount of this binocular enhancement is not dependant on the mode of flicker stimulation (mean binocular: monocular ratio 1.41, 95% CI: 1.2-1.6). Binocular enhancement of F1 for 21.3 Hz flicker was increased to a factor of 2.5 (95% CI: 1.8-3.5). In the healthy adult visual system, FFF-VEP magnitudes can be characterized by the frequency-response functions of F1, F2 and F3. Low-frequency roll-off in the FFF-VEP magnitudes is greater for sinusoidal flicker than for square-wave flicker for rates ≤ 5.29 Hz; magnitudes for higher-frequency flicker are similar for the two types of flicker. Binocular FFF-VEPs are larger overall than those recorded monocularly, and this binocular summation is enhanced at 21.3 Hz in the mid-frequency range.

  4. [Fatigue and stress of anesthesiologists at work--third report: investigation with a flicker photometer and a stabilo-meter].

    Science.gov (United States)

    Sato, O; Kawabata, H; Watanabe, H; Kohro, S; Omote, K; Namiki, A; Kishi, R

    1995-05-01

    We previously studied the fatigue and stress of anesthesiologists at work using a flicker photometer, visual reaction time test, questionnaires, and Holter EKG. In the present study, we investigated the fatigue and stress in seven junior anesthesiologists at work using a flicker photometer and a stabilo-meter. The stabilo-meter measures postural stabilization. We performed each test three times on each subject for a total of twenty-one times. The flicker test and the stabilo-test showed the increase in fatigue in 17 (18%) and in 16 tests (76%), respectively, in all seven subjects. Increase of fatigue in both the flicker and stabilo-tests was observed in 13 tests (61%) of 6 subjects. There was a good relationship between the flicker test and the stabilo-test. Therefore, the stabilo-test appears to be a useful method for investigating the fatigue of anesthesiologists.

  5. The Time Course of Changes in Retinal Vessel Diameter in Response to Differing Durations of Flicker Light Provocation.

    Science.gov (United States)

    Heitmar, Rebekka; Summers, Robert J

    2015-11-01

    To determine the response of retinal vessels to differing durations of flicker light (FL) stimulation. We recorded retinal arterial and venous vessel dilation to 12.5 Hz FL provocation of varying duration (5, 7, 10, and 20 seconds) in 12 healthy young individuals (age range, 26-45 years). All participants underwent a full ocular examination including IOP and blood pressure measurements. Maximum dilation (MD) did not show a significant dependence on flicker duration in arteries, whereas maximum constriction (MC) did. In veins, however, MD significantly increased with flicker duration. Approximately 80% to 90% of MD in arteries is reached within 10 seconds of FL stimulation. The vast majority of arterial dilatory capacity is reached within 10 seconds of FL stimulation even though venous dilation continues strongly. Since MC of arteries shows a significant dependence on flicker duration, measurements at two different durations can provide more information about the retinal vascular system than at a single flicker duration alone.

  6. Ultra Long Period Cepheids: a primary standard candle up to the Hubble flow.

    NARCIS (Netherlands)

    Saha, Abhijit; Fiorentino, Giuliana; Aloisi, Alessandra; van der Marel, Roeland; Annibali, Francesca; Clementini, Gisella; Tosi, Monica; Marconi, Marcella; Musella, Ilaria

    The cosmological distance ladder crucially depends on Classical Cepheids (CCs, with P=3-70d), which are primary distance indicators up to 25 Mpc. Within this volume, only a few SNe Ia have been calibrated through CCs, and even these carry uncertainties from the non-linearity and the metallicity

  7. Altered retinal flicker response indicates microvascular dysfunction in women with preeclampsia.

    Science.gov (United States)

    Brückmann, Andreas; Seeliger, Christin; Lehmann, Thomas; Schleußner, Ekkehard; Schlembach, Dietmar

    2015-10-01

    Flicker-induced dilatation is reduced in patients with cardiovascular risk, and the following arteriolar constriction is reduced with aging, leading to a reduced arteriolar amplitude and, thereby, indicating microvascular endothelial dysfunction. As endothelial dysfunction is associated with preeclampsia, we assessed retinal flicker response during pregnancy and postpartum. Between 2006 and 2013, women were recruited from University Hospital Jena and Prenatal Diagnostic Center Erfurt, Germany, of which 34 women with preeclampsia, 45 women with normal pregnancy, and 22 nonpregnant controls were included in the study. Women with normal pregnancy were matched for age, nulliparity, smoking, previous gestational hypertensive disorders, and family history of cardiovascular disease. Nonpregnant women were age-matched, nulliparous, nonsmoking, without family history of cardiovascular disease. Retinal vessel measurement using Dynamic Vessel Analyzer consisted of 50-seconds baseline acquisition, followed by three 20-second flicker and 80-second relaxation periods. Arteriolar constriction and arteriolar amplitude were reduced during pregnancy (P=0.001 and P=0.008) and postpartum (P=0.018 and P=0.034) in women with preeclampsia, adjusted for age, body mass index, mean arterial pressure, baseline diameter, and family history of cardiovascular disease. Flicker-induced dilatation was unchanged within the groups and throughout the study period. The unchanged flicker-induced dilatation may support a preserved autoregulatory competence of the microvasculature, and the diminished arteriolar amplitude, mainly because of the absence of the arteriolar constriction, indicates a commenced retinal microvascular dysfunction in women with preeclampsia during pregnancy and postpartum. Mechanisms responsible for altered retinal flicker response in preeclampsia need to be clarified in further studies. © 2015 American Heart Association, Inc.

  8. Flicker electroretinograms of eyes with cataract recorded with RETeval system before and after mydriasis.

    Science.gov (United States)

    Miura, Gen; Baba, Takayuki; Oshitari, Toshiyuki; Yamamoto, Shuichi

    2018-01-01

    The aim of this study is to determine the effect of pupil size of eyes with cataracts on the flicker electroretinograms (ERGs) elicited and recorded with the RETeval system. Forty-one eyes of 41 patients (mean age, 76.5±7.3 years) that had grade 2 nuclear or cortical cataract without any other abnormalities were studied. Flicker ERGs were recorded before and after mydriatic drops instillation. The ERGs were elicited by the white light delivered at the frequency of 28.3 Hz and intensities of 2, 8, and 32 Td-s. The amplitudes and the implicit times of the flicker ERGs before and after mydriasis were compared. There were no significant differences between the amplitudes before and after mydriasis ( P =0.35, 2 Td-s; P =0.31, 8 Td-s; P =0.50, 32 Td-s). There were also no significant differences between the implicit times before and after mydriasis ( P =0.86, 2 Td-s; P =0.98, 8 Td-s; P =0.95, 32 Td-s). The mean amplitudes and implicit times of the nuclear and cortical cataracts groups before the mydriasis were also not significantly different from those after mydriasis for all stimulus intensities. The lack of significant differences in the amplitudes and the implicit times of the flicker ERG of cataractous eyes before and after mydriasis indicated that the RETeval flicker ERGs in cataractous eyes is less affected by the pupil diameter. With our earlier study, it was assumed that the effect of cataracts on the RETeval flicker ERGs was due to the opacity of the crystalline lens, and the influence of the cataract would not be reduced or increased by mydriasis.

  9. Flicker-induced retinal arteriole dilation is reduced by ambient lighting.

    Science.gov (United States)

    Noonan, Jonathan E; Dusting, Gregory J; Nguyen, Thanh T; Man, Ryan E K; Best, William J; Lamoureux, Ecosse L

    2014-08-07

    To investigate the impact of ambient room lighting on the magnitude of flicker light-induced retinal vasodilations in healthy individuals. Twenty healthy nonsmokers participated in a balanced 2 × 2 crossover study. Retinal vascular imaging was performed with the dynamic vessel analyzer under reduced or normal ambient lighting, then again after 20 minutes under the alternate condition. Baseline calibers of selected arteriole and venule segments were recorded in measurement units. Maximum percentage dilations from baseline during 20 seconds of luminance flicker were calculated from the mean of three measurement cycles. Within-subject differences were assessed by repeated measures analysis of variance with the assumption of no carryover effects and pairwise comparisons from the fitted model. Mean (SD) maximum arteriole dilations during flicker stimulation under reduced and normal ambient lighting were 4.8% (2.3%) and 4.1% (1.9%), respectively (P = 0.019). Maximum arteriole dilations were (mean ± 95% confidence interval) 0.7% ± 0.6% lower under normal ambient lighting compared with reduced lighting. Ambient lighting had no significant effect on maximum venular dilations during flicker stimulation or on the baseline calibers of arterioles or venules. Retinal arteriole dilation in response to luminance flicker stimulation is reduced under higher ambient lighting conditions. Reduced responses with higher ambient lighting may reflect reduced contrast between the ON and OFF flicker phases. Although it may not always be feasible to conduct studies under reduced lighting conditions, ambient lighting levels should be consistent to ensure that comparisons are valid. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  10. Role of Glial Cells in Regulating Retinal Blood Flow During Flicker-Induced Hyperemia in Cats.

    Science.gov (United States)

    Song, Youngseok; Nagaoka, Taiji; Yoshioka, Takafumi; Nakabayashi, Seigo; Tani, Tomofumi; Yoshida, Akitoshi

    2015-11-01

    To investigate how glial cells participate in retinal circulation during flicker stimulation in cats. Using laser Doppler velocimetry, we measured the vessel diameter and blood velocity simultaneously and calculated the retinal blood flow (RBF) in feline first-order retinal arterioles. Twenty-four hours after intravitreal injections of L-2-aminoadipic acid (LAA), a gliotoxic compound, and the solvent of 0.01 N hydrochloric acid as a control, we examined the changes in RBF in response to 16-Hz flicker stimulation for 3 minutes. We also measured the changes in RBF 2 hours after intravitreal injection of Nω-propyl-L-arginine (L-NPA), a selective neuronal nitric oxide synthase inhibitor, in LAA-treated eyes. To evaluate the effects of LAA on retinal neuronal function, ERGs were monitored. Immunohistochemical examinations were performed. In LAA-treated eyes, histologic changes selectively occurred in retinal glial cells. There were no significant reductions in amplitude or elongation of implicit time in ERG after LAA injections compared with controls. In control eyes, the RBF gradually increased and reached the maximal level (53.5% ± 2.5% increase from baseline) after 2 to 3 minutes of flicker stimulation. In LAA-treated eyes, the increases in RBF during flicker stimulation were attenuated significantly compared with controls. In LAA-treated eyes 2 hours after injection of L-NPA, flicker-evoked increases in RBF decreased significantly compared with LAA-treated eyes. The current results suggested that increases in RBF in response to flicker stimulation were regulated partly by retinal glial cells.

  11. Flicker Study on Variable Speed Wind Turbines with Permanent Magnet Synchronous Generator

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Wang, Yue

    2008-01-01

    Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed in the simul......Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed...

  12. Load and Flicker Mitigation of Grid-Connected Wind Turbines with DFIG

    DEFF Research Database (Denmark)

    Zhang, Yunqian

    , such as loss of a small amount of wind energy at low wind speeds and high demand of the pitch actuation system (PAS), are also pointed out. Taking advantage of the large inertia of the wind turbine rotor, a simple and effective method of Flicker mitigation by generator torque control of DFIG is proposed......, such that the power oscillation is stored as the kinetic energy of the wind turbine. Based on the flickermeter model, flicker level of the DFIG based wind turbine is investigated during continuous operation....

  13. Mitigation of Voltage Dip and Voltage Flickering by Multilevel D-STATCOM

    Directory of Open Access Journals (Sweden)

    M. S. Ballal

    2012-01-01

    Full Text Available The basic power quality problems in the distribution network are voltage sag (dip, voltage flickering, and the service interruptions. STATCOM is a Flexible AC Transmission Systems (FACTS technology device which can independently control the flow of reactive power. This paper presents the simulation and analysis of a STATCOM for voltage dip and voltage flickering mitigation. Simulations are carried out in MATLAB/Simulink to validate the performance of the STATCOM. A comparison between the six-pulse inverter and the five-level diode-clamped inverter is carried out for the performance of 66/11 KV distribution system.

  14. On the anomalous flicker noise intensity in high-temperature superconductors

    International Nuclear Information System (INIS)

    Kazakov, Kirill A.

    2009-01-01

    The problem of anomalously high levels of flicker noise observed in the normal state of the high-temperature superconductors is addressed. It is argued that the anomaly is the result of incorrect normalization of the power spectra according to the Hooge formula. A careful analysis of the available experimental data is given, which shows that the scaling of the spectral power with sample size is essentially different from the inverse proportionality. It is demonstrated that the measured spectra obey the law given by the recently proposed quantum theory of fundamental flicker noise.

  15. The role of amplitude-to-phase conversion in the generation of oscillator flicker phase noise

    Science.gov (United States)

    Hearn, C. P.

    1985-01-01

    The role of amplitude-to-phase conversion as a factor in feedback oscillator flicker phase noise is examined. A limiting stage consisting of parallel-connected opposite polarity diodes operating in a circuit environment contining reactance is shown to exhibit amplitude-to-phase conversion. This mechanism coupled with resistive upconversion provides an indirect route for very low frequency flicker noise to be transferred into the phase of an oscillator signal. It is concluded that this effect is more significant in the lower frequency regimes where the onlinear reactances associated with active devices are overwhelmed by linear reactive elements.

  16. On the origin of optical microvariability and X-ray flickering in active galactic nuclei

    International Nuclear Information System (INIS)

    Chakrabarti, S.K.; Wiita, P.J.

    1990-12-01

    We suggest that non-stationary spiral shocks can produce X-ray flickering and optical microvariability. We show this by detailed non-axisymmetric numerical simulation of accretion disks in a binary system. We show that non-axisymmetric features appear and disappear in time scales of order of few local orbital periods near the inner edge of the disk and shorter than the orbital periods at a large distance. The former type may explain the X-ray flickering and the later type, the optical microvariability. (author). 5 refs, 1 fig

  17. Flicker Sensitivity in Normal Aging--Monocular Tests of Retinal Function at Photopic and Mesopic Light Levels.

    Science.gov (United States)

    Bi, Wei; Gillespie-Gallery, Hanna; Binns, Alison; Barbur, John L

    2016-02-01

    Aging can affect many aspects of visual performance. In general, the effects become more significant in those older than 40 to 50 years, with increased intersubject variability and stronger dependence on ambient illumination. This study aimed to establish how healthy aging of the retina affects the detection of 15-Hz flicker under photopic and mesopic lighting. We investigated 71 participants aged 20 to 75 years. Thresholds were measured for detection of 15-Hz flicker at the fovea (0°) and at an eccentricity of 4° in each of the four quadrants. The background luminance ranged from 0.6 to 60 cd/m(2) and pupil size was measured continuously. Participants were excluded if they had signs/history of ocular disease, substantial interocular differences in flicker thresholds, or were unable to detect 100% flicker modulation in the high mesopic range. Mesopic and photopic flicker thresholds were used to calculate an index, the health of the retina index, to determine the limits of flicker sensitivity in healthy aging. Log flicker thresholds changed bilinearly with age; they remained stable until 40 to 50 years, with a linear decline with increasing age. This bilinear pattern of the change in flicker thresholds with age is consistent across photopic and mesopic light levels. The health of the retina index captures the lowest threshold, usually obtained under photopic conditions, as well as the loss of flicker sensitivity with decreasing light level. The established limits of healthy aging may benefit from future studies in patients with ocular hypertension and/or glaucoma that are known to experience loss of flicker sensitivity.

  18. Central retinal function as measured by the multifocal electroretinogram and flicker perimetry in early age-related macular degeneration.

    Science.gov (United States)

    Gin, Thomas J; Luu, Chi D; Guymer, Robyn H

    2011-11-29

    To determine the retinal function in early age-related macular degeneration (AMD) assessed by the multifocal electroretinogram (mfERG) and flicker perimetry and to seek a relationship between local objective mfERG parameters and subjective flicker perimetry thresholds. mfERG and flicker perimetry were performed in 15 patients (15 eyes) with early AMD and 14 controls (14 eyes) of similar age. The mfERG P1 response amplitude density (nV/deg²) and P1 implicit time of the first-order kernel and the flicker thresholds of each concentric ring were analyzed. The relationship between individual mfERG responses and the corresponding individual flicker sensitivity outcomes was determined. The mfERG response amplitude of the central ring (ring 1) was significantly reduced in early AMD eyes compared with the controls (P = 0.009). No significant difference in mfERG amplitude between early AMD and control eyes was detected in the other rings. The mfERG implicit time was significantly increased in the early AMD eyes but only within the central four rings of 12°. A significant reduction in flicker sensitivity was also detected in early AMD eyes but only within the central 6°. There was a significant, moderate correlation (r = -0.477; P flicker sensitivity from the same tested locations within the central 6°. There was a weak correlation (r = 0.200; P = 0.014) between mfERG amplitude and flicker sensitivity. Both mfERG and flicker perimetry show abnormal retinal function, but only in the very central macula, in early AMD. A novel relationship between mfERG and flicker sensitivity should enhance the clinical monitoring of disease progression.

  19. Fail save shut off valve for filtering systems employing candle filters

    Science.gov (United States)

    VanOsdol, John [Fairmont, WV

    2006-01-03

    The invention relates to an apparatus that acts as a fail save shut off valve. More specifically, the invention relates to a fail save shut off valve that allows fluid flow during normal operational conditions, but prevents the flow of fluids in the event of system failure upstream that causes over-pressurization. The present invention is particularly well suited for use in conjunction with hot gas filtering systems, which utilize ceramic candle filters. Used in such a hot gas system the present invention stops the flow of hot gas and prevents any particulate laden gas from entering the clean side of the system.

  20. DEVELOPMENT AND UTILIZATION OF TEST FACILITY FOR THE STUDY OF CANDLE FILTER SURFACE REGENERATION

    Energy Technology Data Exchange (ETDEWEB)

    Bruce S. Kang; Eric K. Johnson

    2003-07-14

    Hot gas particulate filtration is a basic component in advanced power generation systems such as Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC). These systems require effective particulate removal to protect the downstream gas turbine and also to meet environmental emission requirements. The ceramic barrier filter is one of the options for hot gas filtration. Hot gases flow through ceramic candle filters leaving ash deposited on the outer surface of the filter. A process known as surface regeneration removes the deposited ash periodically by using a high pressure pulse of gas to back flush the filter. After this cleaning process has been completed there may be some residual ash on the filter surface. This residual ash may grow and this may then lead to mechanical failure of the filter. A Room Temperature Test Facility (RTTF) and a High Temperature Test Facility (HTTF) were built to investigate the ash characteristics during surface regeneration at room and selected high temperatures. The RTTF system was used to gain experience with the selected instrumentation and develop an operating procedure to be used later at elevated temperatures. The HTTF system is capable of conducting surface regeneration tests of a single candle filter at temperatures up to 1500 F. In order to obtain sequential digital images of ash particle distribution during the surface regeneration process, a high resolution, high speed image acquisition system was integrated into the HTTF system. The regeneration pressure and the transient pressure difference between the inside of the candle filter and the chamber during regeneration were measured using a high speed PC data acquisition system. The control variables for the high temperature regeneration tests were (1) face velocity, (2) pressure of the back pulse, and (3) cyclic ash built-up time. Coal ash sample obtained from the Power System Development Facility (PSDF) at Wilsonville, AL was used at the

  1. Linearized Model of Electrical Arc Furnace Suitable for Analysis of Flicker Mitigation

    Czech Academy of Sciences Publication Activity Database

    Valouch, Viktor

    2003-01-01

    Roč. 48, č. 2 (2003), s. 147-156 ISSN 0001-7043 R&D Projects: GA AV ČR IAA2057301 Institutional research plan: CEZ:AV0Z2057903 Keywords : flicker * electrical arc furnace * unified power quality conditioner Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  2. A flicker noise/IM3 cancellation technique for active mixer using negative impedance

    NARCIS (Netherlands)

    Cheng, W.; Annema, Anne J.; Wienk, Gerhardus J.M.; Nauta, Bram

    2013-01-01

    Abstract—This paper presents an approach to simultaneously cancel flicker noise and IM3 in Gilbert-type mixers, utilizing negative impedances. For proof of concept, two prototype double-balanced mixers in 0.16- m CMOS are fabricated. The first demonstration mixer chip was optimized for full IM3

  3. Comment on: Flicker-noise fluctuations in α-radioactive decay

    International Nuclear Information System (INIS)

    Prestwych, W.V.; Kennett, T.J.; Pepper, G.T.

    1988-01-01

    A discrepancy between experiments to establish the existence of 1/f fluctuations in α decay is discussed. It is argued that the flicker floor reported for direct α counting cannot be due to fluctuations intrinsic to the decay process. (2 refs.)

  4. Detection of changes in the structure of a system according to changes of its flicker noise

    International Nuclear Information System (INIS)

    Kolodiy, Z.A.

    2008-01-01

    The results of computer simulations of a chaotic motion of elementary particles in the systems with chaotic or ordered structure are presented. The conclusion about the possibility to use the flicker noise of a system for the qualitative estimation of its inner structure and changes in the structure is made

  5. Flicker electroretinograms recorded with mydriasis-free RETeval system before and after cataract surgery.

    Science.gov (United States)

    Miura, G; Sato, E; Yamamoto, S

    2017-11-01

    PurposeThe purpose of this study is to compare the amplitudes and peak times of the flicker electroretinograms (ERGs) recorded before and after cataract surgery with the RETeval system (LKC Technologies, Gaithersburg, MD, USA) from eyes without dilation.Patients and methodsThirty-two eyes of 32 patients (77.3±6.5 years) that had grade 2 Emery-Little nuclear or cortical cataract without any other abnormalities were studied. Flicker ERGs were recorded with the RETeval system under mydriatic-free conditions. Skin electrodes were used to pick-up the ERGs that were elicited by white light delivered at a rate of 28.3 Hz and intensity of 2, 8, and 32 Td-s. The amplitudes and peak times of the flicker ERGs before and after cataract surgery were compared.ResultsThe mean amplitudes were significantly increased after the removal of the cataractous lenses at the three stimulus intensities (2 Td-s, Pflicker ERGs elicited by 2 and 8 Td-s were significantly shortened after the surgery (2 td-s, Pflicker ERGs even if the cataract is mild. In addition, the results indicate that as stimulus intensity increases, the peak times is less affected by a cataract. The clarity of the crystalline lens should be considered when interpreting the flicker ERGs recorded with the RETeval system.

  6. Using an abstract geometry in virtual reality to explore choice behaviour: visual flicker preferences in honeybees.

    Science.gov (United States)

    Van De Poll, Matthew N; Zajaczkowski, Esmi L; Taylor, Gavin J; Srinivasan, Mandyam V; van Swinderen, Bruno

    2015-11-01

    Closed-loop paradigms provide an effective approach for studying visual choice behaviour and attention in small animals. Different flying and walking paradigms have been developed to investigate behavioural and neuronal responses to competing stimuli in insects such as bees and flies. However, the variety of stimulus choices that can be presented over one experiment is often limited. Current choice paradigms are mostly constrained as single binary choice scenarios that are influenced by the linear structure of classical conditioning paradigms. Here, we present a novel behavioural choice paradigm that allows animals to explore a closed geometry of interconnected binary choices by repeatedly selecting among competing objects, thereby revealing stimulus preferences in an historical context. We used our novel paradigm to investigate visual flicker preferences in honeybees (Apis mellifera) and found significant preferences for 20-25 Hz flicker and avoidance of higher (50-100 Hz) and lower (2-4 Hz) flicker frequencies. Similar results were found when bees were presented with three simultaneous choices instead of two, and when they were given the chance to select previously rejected choices. Our results show that honeybees can discriminate among different flicker frequencies and that their visual preferences are persistent even under different experimental conditions. Interestingly, avoided stimuli were more attractive if they were novel, suggesting that novelty salience can override innate preferences. Our recursive virtual reality environment provides a new approach to studying visual discrimination and choice behaviour in animals. © 2015. Published by The Company of Biologists Ltd.

  7. Variables Influencing The Perception of Flicker In Wide Angle CRT Displays.

    Science.gov (United States)

    Welde, William L.; Cream, Bertram W.

    An experiment was conducted to determine the influence of three variables on the perception of the psychophysical phenomenon of flicker in wide angle cathode ray tube (CRT) displays. The three independent variables treated in the experiment were: 3, 6, and 9 foot-lambers (FL) illumination levels; four images, three static and one dynamic; and 26…

  8. Revealing the neural response to imperceptible peripheral flicker with machine learning.

    Science.gov (United States)

    Porbadnigk, Anne K; Scholler, Simon; Blankertz, Benjamin; Ritz, Arnd; Born, Matthias; Scholl, Robert; Muller, Klaus-Robert; Curio, Gabriel; Treder, Matthias S

    2011-01-01

    Lighting in modern-day devices is often discrete. The sharp onsets and offsets of light are known to induce a steady-state visually evoked potential (SSVEP) in the electroencephalogram (EEG) at low frequencies. However, it is not well-known how the brain processes visual flicker at the threshold of conscious perception and beyond. To shed more light on this, we ran an EEG study in which we asked participants (N=6) to discriminate on a behavioral level between visual stimuli in which they perceived flicker and those that they perceived as constant wave light. We found that high frequency flicker which is not perceived consciously anymore still elicits a neural response in the corresponding frequency band of EEG, con-tralateral to the stimulated hemifield. The main contribution of this paper is to show the benefit of machine learning techniques for investigating this effect of subconscious processing: Common Spatial Pattern (CSP) filtering in combination with classification based on Linear Discriminant Analysis (LDA) could be used to reveal the effect for additional participants and stimuli, with high statistical significance. We conclude that machine learning techniques are a valuable extension of conventional neurophysiological analysis that can substantially boost the sensitivity to subconscious effects, such as the processing of imperceptible flicker.

  9. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Hu, Weihao; Zhang, Yunqian; Chen, Zhe

    2013-01-01

    Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG...

  10. Inferior parietal lobule encodes visual temporal resolution processes contributing to the critical flicker frequency threshold in humans.

    Directory of Open Access Journals (Sweden)

    Andrea Nardella

    Full Text Available The measurement of the Critical Flicker Frequency threshold is used to study the visual temporal resolution in healthy subjects and in pathological conditions. To better understand the role played by different cortical areas in the Critical Flicker Frequency threshold perception we used continuous Theta Burst Stimulation (cTBS, an inhibitory plasticity-inducing protocol based on repetitive transcranial magnetic stimulation. The Critical Flicker Frequency threshold was measured in twelve healthy subjects before and after cTBS applied over different cortical areas in separate sessions. cTBS over the left inferior parietal lobule altered the Critical Flicker Frequency threshold, whereas cTBS over the left mediotemporal cortex, primary visual cortex and right inferior parietal lobule left the Critical Flicker Frequency threshold unchanged. No statistical difference was found when the red or blue lights were used. Our findings show that left inferior parietal lobule is causally involved in the conscious perception of Critical Flicker Frequency and that Critical Flicker Frequency threshold can be modulated by plasticity-inducing protocols.

  11. Inferior parietal lobule encodes visual temporal resolution processes contributing to the critical flicker frequency threshold in humans.

    Science.gov (United States)

    Nardella, Andrea; Rocchi, Lorenzo; Conte, Antonella; Bologna, Matteo; Suppa, Antonio; Berardelli, Alfredo

    2014-01-01

    The measurement of the Critical Flicker Frequency threshold is used to study the visual temporal resolution in healthy subjects and in pathological conditions. To better understand the role played by different cortical areas in the Critical Flicker Frequency threshold perception we used continuous Theta Burst Stimulation (cTBS), an inhibitory plasticity-inducing protocol based on repetitive transcranial magnetic stimulation. The Critical Flicker Frequency threshold was measured in twelve healthy subjects before and after cTBS applied over different cortical areas in separate sessions. cTBS over the left inferior parietal lobule altered the Critical Flicker Frequency threshold, whereas cTBS over the left mediotemporal cortex, primary visual cortex and right inferior parietal lobule left the Critical Flicker Frequency threshold unchanged. No statistical difference was found when the red or blue lights were used. Our findings show that left inferior parietal lobule is causally involved in the conscious perception of Critical Flicker Frequency and that Critical Flicker Frequency threshold can be modulated by plasticity-inducing protocols.

  12. Flicker electroretinograms of eyes with cataract recorded with RETeval system before and after mydriasis

    Directory of Open Access Journals (Sweden)

    Miura G

    2018-03-01

    Full Text Available Gen Miura, Takayuki Baba, Toshiyuki Oshitari, Shuichi Yamamoto Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan Purpose: The aim of this study is to determine the effect of pupil size of eyes with cataracts on the flicker electroretinograms (ERGs elicited and recorded with the RETeval system.Patients and methods: Forty-one eyes of 41 patients (mean age, 76.5±7.3 years that had grade 2 nuclear or cortical cataract without any other abnormalities were studied. Flicker ERGs were recorded before and after mydriatic drops instillation. The ERGs were elicited by the white light delivered at the frequency of 28.3 Hz and intensities of 2, 8, and 32 Td-s. The amplitudes and the implicit times of the flicker ERGs before and after mydriasis were compared.Results: There were no significant differences between the amplitudes before and after mydriasis (P=0.35, 2 Td-s; P=0.31, 8 Td-s; P=0.50, 32 Td-s. There were also no significant differences between the implicit times before and after mydriasis (P=0.86, 2 Td-s; P=0.98, 8 Td-s; P=0.95, 32 Td-s. The mean amplitudes and implicit times of the nuclear and cortical cataracts groups before the mydriasis were also not significantly different from those after mydriasis for all stimulus intensities.Conclusion: The lack of significant differences in the amplitudes and the implicit times of the flicker ERG of cataractous eyes before and after mydriasis indicated that the RETeval flicker ERGs in cataractous eyes is less affected by the pupil diameter. With our earlier study, it was assumed that the effect of cataracts on the RETeval flicker ERGs was due to the opacity of the crystalline lens, and the influence of the cataract would not be reduced or increased by mydriasis. Keywords: electroretinogram, ERG, flicker ERG, cataract, RETeval

  13. The effect of hypercapnia on the sensitivity to flicker defined stimuli.

    Science.gov (United States)

    Shahidi, A M; Hudson, C; Patel, S R; Flanagan, J G

    2015-03-01

    To investigate the effect of increased CO2 levels on flicker defined stimuli. The sensitivity of two flicker defined tasks was measured in nine healthy, trained observers using the Flicker Defined Form (FDF) stimulus of the Heidelberg Edge Perimeter (HEP; Heidelberg Engineering) and Frequency Doubling Technology (FDT) stimulus of the Matrix perimeter (Carl Zeiss Meditec) during normoxia and 15% hypercapnia (end-tidal CO2 increased by 15% relative to baseline). HEP-FDF and Matrix-FDT sensitivities were analysed for the global field, superior and inferior hemifields and at specific matched eccentricities, using repeated measures analysis of variance. The main effect of hypercapnia on flicker sensitivity was analysed using regression models. Higher flicker sensitivity outcomes with increasing CO2 values were found for HEP-FDF and Matrix-FDT with a statistically significant main effect for HEP-FDF global, superior and inferior hemifields (p0.05). As CO2 levels were increased in healthy young individuals, there was an associated increase in visual sensitivity that was only significant for HEP-FDF stimuli, highlighting the different mechanisms involved in processing each of HEP-FDF and Matrix-FDT stimuli. Mean visual sensitivity outcomes were found to be similar for normocapnia and hypercapnia suggesting that a capability to compensate for a mild and stable increase in systemic CO2 levels may exist. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  14. A Double Candle-Flame-Shaped Solar Flare Observed by SDO and STEREO

    Science.gov (United States)

    Gou, T.; Liu, R.; Wang, Y.; Liu, K.; Zhuang, B.; Zhang, Q.; Liu, J.

    2015-12-01

    We investigate an M1.4 flare occurring on 2011 January 28 near the northwest solar limb. The flare loop system exhibits a double candle-flame configuration in SDO/AIA's hot passbands, sharing a much larger cusp-shaped structure. The results of DEM analysis show that each candle flame has a similar temperature distribution as the famous Tsuneta flare. STEREO-A provides us a view from directly above the flare, and in SECCHI/EUVI 195 Å the post-flare loops are observed to propagate eastward. We performed a 3D reconstruction of the pos-flare loops with AIA and EUVI data. With the aid of the squashing factor Q based on a potential extrapolation of the photospheric field, we recognized that the footpoints of the post-flare loops were slipping along high-Q lines on the photosphere, and the reconstructed loops share similarity with the filed lines that are traced starting from the high-Q lines. The heights of the loops increase as they slip horizontally eastward, giving the loop-top a velocity of about 10 km/s. An extremely large EUV late phase in Fe XVI 33.5 nm observed by SDO/EVE is suggested to be related to the slipping magnetic reconnection occurring in the quasi-separatrix layers (QSLs) whose photosheric footprints are featured by the high-Q lines.

  15. Void effect analysis of Pb-208 of fast reactors with modified CANDLE burn-up scheme

    Science.gov (United States)

    Widiawati, Nina; Su'ud, Zaki

    2015-09-01

    Void effect analysis of Pb-208 as coolant of fast reactors with modified candle burn-up scheme has been conducted. Lead cooled fast reactor (LFR) is one of the fourth-generation reactor designs. The reactor is designed with a thermal power output of 500 MWt. Modified CANDLE burn-up scheme allows the reactor to have long life operation by supplying only natural uranium as fuel cycle input. This scheme introducing discrete region, the fuel is initially put in region 1, after one cycle of 10 years of burn up it is shifted to region 2 and region 1 is filled by fresh natural uranium fuel. The reactor is designed for 100 years with 10 regions arranged axially. The results of neutronic calculation showed that the void coefficients ranged from -0.6695443 % at BOC to -0.5273626 % at EOC for 500 MWt reactor. The void coefficients of Pb-208 more negative than Pb-nat. The results showed that the reactors with Pb-208 coolant have better level of safety than Pb-nat.

  16. Аssociation of spectral closeness of flicker-noise parameters with features of underlying structure of system

    Directory of Open Access Journals (Sweden)

    Kolodiy Z. A.

    2009-02-01

    Full Text Available The results of computer design of chaotic motion of elementary particles are resulted in a flat rectangle which can be put in accordance to a pellicle resistor with the electrons of conductivity. The analysis of spectral closeness of chaotic motion shows that one of parameters of flicker-noise depends only on the amount of elementary particles and middle rate of their movement. The second parameter of flicker-noise (time of relaxation depends on the features of underlying structure of the system. It can be used for prognostication of reliability as separate elements of electronics so apparatus as a whole on the measured level of their flicker-noise.

  17. Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor

    Science.gov (United States)

    Afifah, Maryam; Miura, Ryosuke; Su'ud, Zaki; Takaki, Naoyuki; Sekimoto, H.

    2015-09-01

    Fast Breeder Reactor had been interested to be developed over the world because it inexhaustible source energy, one of those is CANDLE reactor which is have strategy in burn-up scheme, need not control roads for control burn-up, have a constant core characteristics during energy production and don't need fuel shuffling. The calculation was made by basic reactor analysis which use Sodium coolant geometry core parameter as a reference core to study on minimum core reactor radius of CANDLE for long life Pb-Bi cooled, also want to perform pure coolant effect comparison between LBE and sodium in a same geometry design. The result show that the minimum core radius of Lead Bismuth cooled CANDLE is 100 cm and 500 MWth thermal output. Lead-Bismuth coolant for CANDLE reactor enable to reduce much reactor size and have a better void coefficient than Sodium cooled as the most coolant for FBR, then we will have a good point in safety analysis.

  18. Fabrication of Water Jet Resistant and Thermally Stable Superhydrophobic Surfaces by Spray Coating of Candle Soot Dispersion.

    Science.gov (United States)

    Qahtan, Talal F; Gondal, Mohammed A; Alade, Ibrahim O; Dastageer, Mohammed A

    2017-08-08

    A facile synthesis method for highly stable carbon nanoparticle (CNP) dispersion in acetone by incomplete combustion of paraffin candle flame is presented. The synthesized CNP dispersion is the mixture of graphitic and amorphous carbon nanoparticles of the size range of 20-50 nm and manifested the mesoporosity with an average pore size of 7 nm and a BET surface area of 366 m 2 g -1 . As an application of this material, the carbon nanoparticle dispersion was spray coated (spray-based coating) on a glass surface to fabricate superhydrophobic (water contact angle > 150° and sliding angle fabricated from direct candle flame soot deposition (candle-based coating). This study proved that water jet resistant and thermally stable superhydrophobic surfaces can be easily fabricated by simple spray coating of CNP dispersion gathered from incomplete combustion of paraffin candle flame and this technique can be used for different applications with the potential for the large scale fabrication.

  19. Autocorrelation and Cross-Correlation Analyses of Alpha Waves in Reflection to Subjective Preference of a Flickering Light

    National Research Council Canada - National Science Library

    Soeta, Y

    2001-01-01

    To clarify the relationship between the human brain activity and subjective preference of a flickering light under changing temporal frequency and mean luminance, alpha waves were analyzed by autocorrelation function (ACF...

  20. What speeds up the internal clock? Effects of clicks and flicker on duration judgements and reaction time.

    Science.gov (United States)

    Wearden, J H; Williams, Emily A; Jones, Luke A

    2017-03-01

    Four experiments investigated the effect of pre-stimulus events on judgements of the subjective duration of tones that they preceded. Experiments 1 to 4 used click trains, flickering squares, expanding circles, and white noise as pre-stimulus events and showed that (a) periodic clicks appeared to "speed up" the pacemaker of an internal clock but that the effect wore off over a click-free delay, (b) aperiodic click trains, and visual stimuli in the form of flickering squares and expanding circles, also produced similar increases in estimated tone duration, as did white noise, although its effect was weaker. A fifth experiment examined the effects of periodic flicker on reaction time and showed that, as with periodic clicks in a previous experiment, reaction times were shorter when preceded by flicker than without.

  1. Impact of co-flow air on buoyant diffusion flames flicker

    International Nuclear Information System (INIS)

    Gohari Darabkhani, H.; Wang, Q.; Chen, L.; Zhang, Y.

    2011-01-01

    Highlights: → We present the co-flow effects on flickering behaviour of diffusion flames. → Co-flow air is shown to fully suppress the buoyancy driven flame oscillations. → Schlieren and PIV illustrate the shift of outer vortices beyond the flame zone. → Stability controlling parameter as a ratio of air to fuel velocities is presented. → Equation for linear increase in flickering frequency by co-flow air is presented. - Abstract: This paper describes experimental investigation of co-flow air velocity effects on the flickering behaviour of laminar non-lifted methane diffusion flames. Chemiluminescence, high-speed photography, schlieren and Particle Imaging Velocimetry (PIV), have been used to study the changes in the flame/vortex interactions as well as the flame flickering frequency and magnitude by the co-flow air. Four cases of methane flow rates at different co-flow air velocities are investigated. It has been observed that the flame dynamics and stability of co-flow diffusion flames are strongly affected by the co-flow air velocity. When the co-flow velocity has reached a certain value the buoyancy driven flame oscillation was completely suppressed. The schlieren and PIV imaging have revealed that the co-flow of air is able to push the initiation point of the outer toroidal vortices beyond the visible flame to create a very steady laminar flow region in the reaction zone. Then the buoyancy driven instability is only effective in the plume of hot gases above the visible flame. It is observed that a higher co-flow rate is needed in order to suppress the flame flickering at a higher fuel flow rate. Therefore the ratio of the air velocity to the fuel velocity, γ, is a stability controlling parameter. The velocity ratio, γ, was found to be 0.72 for the range of tested flow rates. The dominant flickering frequency was observed to increase linearly with the co-flow rate (a) as; f = 0.33a + 11. The frequency amplitudes, however, were observed to

  2. Transient twinkle perception is induced by sequential presentation of stimuli that flicker at frequencies above the critical fusion frequency.

    Science.gov (United States)

    Nakajima, Yutaka; Sakaguchi, Yutaka

    2015-11-01

    The critical fusion frequency (CFF) is a threshold that represents the temporal limits of the human visual system. If two flickering stimuli with equal subjective luminances are presented simultaneously at different locations, the CFF is the temporal frequency above which they cannot be distinguished. However, when the stimuli are presented sequentially at the same position, a transient twinkle can be perceived around the moment of the changeover. To investigate the mechanism underlying this transient twinkle perception (TTP), we independently manipulated the luminance contrast and temporal frequency of the flicker, as well as the interstimulus interval (ISI). We found that TTP was greater as the luminance step was larger, was stably perceived for flicker frequencies up to 200 Hz, and was robust for all ISIs if flicker frequencies were below 250 Hz. For 250- and 300-Hz flickers, TTP was attenuated in conditions in which one-frame and two-frame ISIs were inserted. These results can be explained by a simple filtering model: TTP occurs if the temporal change in the weighted moving average of stimulus luminance exceeds a certain threshold. TTP gives additional evidence that the human visual system can detect the transient change of flicker stimuli at much higher temporal frequencies than the CFF, by an averaging mechanism of luminance.

  3. Effect of Pupil Size on Flicker ERGs Recorded With RETeval System: New Mydriasis-Free Full-Field ERG System.

    Science.gov (United States)

    Kato, Kumiko; Kondo, Mineo; Sugimoto, Masahiko; Ikesugi, Kengo; Matsubara, Hisashi

    2015-06-01

    We studied whether pupil size affects the flicker electroretinograms (ERGs) recorded by RETeval, a new mydriasis-free full-field flicker ERG system. We studied 10 healthy subjects. The RETeval manufacturer claims that the system delivers a constant flash retinal illuminance by adjusting the flash luminance to compensate for changes in the pupil size. Two experiments were performed. First, the flicker ERG was recorded every 3 minutes after the instillation of mydriatics. Second, the flicker ERG was recorded while the subjects wore soft contact lenses with two different artificial pupil sizes. The first experiment showed that as pupil size increased, the amplitudes of the fundamental component of the flicker ERG did not change significantly, but the implicit times of the fundamental component were significantly prolonged for larger pupil sizes. There was a significant positive correlation between the pupillary area and implicit time of the fundamental component (r = 0.93, P flicker ERG were significantly longer with larger artificial pupil. The results suggest that the effective retinal illuminance of the stimulus delivered by the RETeval system decreases for large pupil sizes. However, in most clinical testing situations, patients' undilated pupils will likely be sufficiently small to fall within the range for which the system delivers a stimulus of constant retinal illuminance.

  4. Tracking themes in Manuchehri’s candle conundrum in Arabic and Persian poetry till the end of 7th century AH

    Directory of Open Access Journals (Sweden)

    Parvane Saneai

    2016-09-01

     Manouchehri has derived some of his themes for ode of candle conundrum from Arabic literature. Following him, other poets have applied such themes in their poets. In fact, at the beginning of this stream is seen the composition of candle conundrum whose first symptoms can be seen in Arab poetry. Following Manouchehri, the poets have used in their poems the themes as follows: Shortening the wick of the candle, candles’ yellow face, candles’ laughing and crying, candles’ soul and body, Love and Lovers.

  5. Development of CANDLES low background HPGe detector and half-life measurement of 180Tam

    Science.gov (United States)

    Chan, W. M.; Kishimoto, T.; Umehara, S.; Matsuoka, K.; Suzuki, K.; Yoshida, S.; Nakajima, K.; Iida, T.; Fushimi, K.; Nomachi, M.; Ogawa, I.; Tamagawa, Y.; Hazama, R.; Takemoto, Y.; Nakatani, N.; Takihira, Y.; Tozawa, M.; Kakubata, H.; Trang, V. T. T.; Ohata, T.; Tetsuno, K.; Maeda, T.; Khai, B. T.; Li, X. L.; Batpurev, T.

    2018-01-01

    A low background HPGe detector system was developed at CANDLES Experimental Hall for multipurpose use. Various low background techniques were employed, including hermatic shield design, radon gas suppression, and background reduction analysis. A new pulse shape discrimination (PSD) method was specially created for coaxial Ge detector. Using this PSD method, microphonics noise and background event at low energy region less than 200 keV can be rejected effectively. Monte Carlo simulation by GEANT4 was performed to acquire the detection efficiency and study the interaction of gamma-rays with detector system. For rare decay measurement, the detector was utilized to detect the nature's most stable isomer tantalum-180m (180Tam) decay. Two phases of tantalum physics run were completed with total livetime of 358.2 days, which Phase II has upgraded shield configuration. The world most stringent half-life limit of 180Tam has been successfully achieved.

  6. Polymer-based candle-shaped microneedle electrodes for electroencephalography on hairy skin

    Science.gov (United States)

    Arai, Miyako; Kudo, Yuta; Miki, Norihisa

    2016-06-01

    In this paper, we report on the optimization of the shape of dry microneedle electrodes for electroencephalography (EEG) on hairy locations and compare the electrodes we developed with conventional wet electrodes. We propose the use of SU-8-based candle-shaped microneedle electrodes (CMEs), which have pillars of 1.0 mm height and 0.4 mm diameter with a gap of 0.43 mm between pillars. Microneedles are formed on the top of the pillars. The shape was determined by how well the pillars can avoid hairs and support the microneedles to penetrate through the stratum corneum. The skin-electrode contact impedances of the fabricated CMEs were found to be higher and less stable than those of conventional wet electrodes. However, the CMEs successfully acquired signals with qualities as good as those of conventional wet electrodes. Given the usability of the CMEs, which do not require skin preparation or gel, they are promising alternatives to conventional wet electrodes.

  7. Flicker Mitigation by Active Power Control of Variable-Speed Wind Turbines With Full-Scale Back-to-Back Power Converters

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Wang, Zhaoan

    2009-01-01

    /EMTDC. Flicker emission of this system is investigated. Reactive power compensation is mostly adopted for flicker mitigation. However, the flicker mitigation technique shows its limits, when the grid impedance angle is low in some distribution networks. A new method of flicker mitigation by controlling active...... power is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the dc-link voltage of the full-scale converter. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation controller......Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation.This paper presents a simulation model of a megawatt-level variablespeed wind turbine with a full-scale back-to-back power converter developed in the simulation tool of PSCAD...

  8. Lattice transitions and flickering images in aged Cu-Mn alloys

    International Nuclear Information System (INIS)

    Perkins, J.; Adachi, K.

    1995-01-01

    Distinctive ''flickering'' movements are observed in TEM images of the microstructure of Cu-Mn alloys after aging within the miscibility gap. Analyses of two-beam image extinction and electron diffraction streaks indicate that the underlying tweed and ''V-shaped'' images involve a static displacement field of the type {110} left angle 1 anti 10 right angle. Atomic force microscopy and other microanalyses show the presence of Mn-enriched colonies of 15-40 nm, formed throughout the microstructure, in which twinned fct crystallites are induced and confined. The flickering movements are interpreted as a direct manifestation of the fcc=>fct transformation event and in particular of a rotation of the fct c-axis, these effects being caused by an inelastic interaction between left angle 110 right angle left angle 1 anti 10 right angle phonons and the accelerated electrons of the incident TEM beam. (orig.)

  9. Flicker-defined form stimuli are minimally affected by centre-surround lateral contrast interactions.

    Science.gov (United States)

    Denniss, Jonathan; McKendrick, Allison M

    2016-03-01

    Flicker-defined form (FDF) stimuli have recently been adopted for visual field testing. A key difference between FDF and traditional perimetric stimuli is that the entire display background contains flickering dots. The purpose of this study was to determine whether the perception of FDF stimuli is influenced by lateral interactions involving regions beyond the stimulus border in young healthy observers. Experiment 1 measured the effect of surround size and retinal eccentricity on the detection of the FDF contour. Psychometric functions were collected for surround diameters of 20°, 30° and 40°, and with stimuli centred at eccentricities of 0°, 10° and 20°. Experiment 2 measured the effect of target-surround temporal phase difference on apparent temporal contrast (flicker strength) of the target for both the FDF stimulus and a solid-field stimulus. Psychometric functions were collected for target-surround phase differences of 0°, 45°, 90°, 135° and 180°. Our results show a mild surround-suppression effect for FDF stimuli that is independent of surround size. Magnitudes of FDF surround suppression were consistent with the reduced temporal contrast energy of the stimulus compared to solid-field stimuli. FDF stimuli necessarily have both flickering target and background. Our results suggest that visual field defects outside the target are unlikely to markedly influence the detection and perception of the FDF stimulus. Nevertheless, mild surround suppression of contrast arises for FDF stimuli, hence interactions between the background and the target area may influence FDF results in conditions that alter centre-surround perceptual effects. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

  10. Assessment of the Absolute Excitatory Level of the Retina by Flicker ERG.

    Science.gov (United States)

    Tanimoto, Naoyuki; Seeliger, Mathias W

    2018-01-01

    Electroretinography (ERG) is important for functional diagnostics of the retina. Types of information about retinal function obtainable by ERG differ depending on recording conditions, e.g., a combination of light stimulus and adaptation. In terms of stimulation, single-flash and flicker stimuli are frequently used because response properties have been well investigated, allowing an assessment of fundamental retinal functionality; for example, how photoreceptors and bipolar cells, including signal transmission between them, are affected under pathological conditions. Usually, ERGs are recorded with a nonzero lower cutoff frequency of amplifiers to avoid certain artifacts, and additionally, responses are averaged over time so that non-event-related signals are cancelled out. However, the improved signal quality is associated with a loss of information. Especially in steady-state flicker ERG, information about the absolute baseline of recordings is missing because the prestimulus baseline is not included on the recording trace as well as because a zero response is obtained in all cases in which the signal baseline stays constant for a sufficient amount of time. In other words, it is impossible to tell from the conventional flicker ERG whether a zero signal is obtained under conditions of maximal or no excitation of the visual system. In this chapter, we describe a direct current ERG protocol (featuring a lower cutoff frequency of zero) with repetitive single flashes mimicking conventional flicker that contains a defined onset. Using this recording protocol, it is possible to assess not only the absolute excitatory level of the retina but also the development of steady-state responses from the single flash response.

  11. Temporal Properties of Flicker ERGs in Rabbit Model of Retinitis Pigmentosa.

    Science.gov (United States)

    Okado, Satoshi; Ueno, Shinji; Kominami, Taro; Nakanishi, Ayami; Inooka, Daiki; Sayo, Akira; Kondo, Mineo; Terasaki, Hiroko

    2017-10-01

    We determined the effects of a remodeled inner retina on the flicker electroretinograms (ERGs) in a rabbit eye at an advanced stage of inherited retinal degeneration. Six wild-type (WT) and four rhodopsin P347L transgenic (Tg) rabbits were studied at 18 months of age. Flicker ERGs were elicited by sinusoidal stimuli at frequencies of 3.906 to 50.781 Hz. To block the ON and OFF retinal pathways, 2-amino-4-phosphonobutyric acid (APB), and 6-cyano-7-nitroquinoxaline-2, 3(1H, 4H)-dione (CNQX), respectively, were injected intravitreally. The amplitudes and phases of the fundamental components of the pre- and postdrug ERGs were analyzed. The postsynaptic APB (ON-) and CNQX (OFF-) sensitive components were determined by examining the phases and amplitude vectors. The temporal properties of the Tg rabbits were different from those of the WT rabbits and had unique features; at 3.906 Hz, the amplitude was depressed but it increased by more than 3.5-fold at 15.625 Hz. The reduction of the amplitude at 3.906 Hz in Tg rabbits was caused by a cancelation of the ON and OFF components by a phase difference of 180°. On the other hand, an increase in the amplitude at 15.625 Hz in Tg rabbits was caused by the summation of the ON and OFF components, which had an approximate 120° phase difference. The temporal properties of the flicker ERGs of Tg rabbits were affected markedly by the remodeling of the retinal neurons. Evaluations of the flicker ERGs in RP eyes must be done with careful considerations of the current findings.

  12. Flow rate pulsations of water with flicker power spectrum in an industrial sodium steam generator

    International Nuclear Information System (INIS)

    Reshetnikov, A.V.; Koverda, V.P.; Skokov, V.N.; Karpenko, A.I.; Govorov, P.P.; Bel'tyukov, A.I.

    2005-01-01

    The study on the spectral characteristics of the water flow pulsations in the evaporating modulus of the steam generator with sodium power unit BN-600 at the nominal capacity is carried out. It is shown that the outflow pulsations capacity spectrum changes inversely with the frequency (flicker pulsations). Origination of the identified high-energy low-frequency pulsations of the water outflow is related to the critical mode of the heat exchange, realized in the evaporation modulus [ru

  13. HyperCube: A Small Lensless Position Sensing Device for the Tracking of Flickering Infrared LEDs.

    Science.gov (United States)

    Raharijaona, Thibaut; Mignon, Paul; Juston, Raphaël; Kerhuel, Lubin; Viollet, Stéphane

    2015-07-08

    An innovative insect-based visual sensor is designed to perform active marker tracking. Without any optics and a field-of-view of about 60°, a novel miniature visual sensor is able to locate flickering markers (LEDs) with an accuracy much greater than the one dictated by the pixel pitch. With a size of only 1 cm3 and a mass of only 0.33 g, the lensless sensor, called HyperCube, is dedicated to 3D motion tracking and fits perfectly with the drastic constraints imposed by micro-aerial vehicles. Only three photosensors are placed on each side of the cubic configuration of the sensing device, making this sensor very inexpensive and light. HyperCube provides the azimuth and elevation of infrared LEDs flickering at a high frequency (>1 kHz) with a precision of 0.5°. The minimalistic design in terms of small size, low mass and low power consumption of this visual sensor makes it suitable for many applications in the field of the cooperative flight of unmanned aerial vehicles and, more generally, robotic applications requiring active beacons. Experimental results show that HyperCube provides useful angular measurements that can be used to estimate the relative position between the sensor and the flickering infrared markers.

  14. Utilizing Retinotopic Mapping for a Multi-Target SSVEP BCI With a Single Flicker Frequency.

    Science.gov (United States)

    Maye, Alexander; Zhang, Dan; Engel, Andreas K

    2017-07-01

    In brain-computer interfaces (BCIs) that use the steady-state visual evoked response (SSVEP), the user selects a control command by directing attention overtly or covertly to one out of several flicker stimuli. The different control channels are encoded in the frequency, phase, or time domain of the flicker signals. Here, we present a new type of SSVEP BCI, which uses only a single flicker stimulus and yet affords controlling multiple channels. The approach rests on the observation that the relative position between the stimulus and the foci of overt attention result in distinct topographies of the SSVEP response on the scalp. By classifying these topographies, the computer can determine at which position the user is gazing. Offline data analysis in a study on 12 healthy volunteers revealed that 9 targets can be recognized with about 95±3% accuracy, corresponding to an information transfer rate (ITR) of 40.8 ± 3.3 b/min on average. We explored how the classification accuracy is affected by the number of control channels, the trial length, and the number of EEG channels. Our findings suggest that the EEG data from five channels over parieto-occipital brain areas are sufficient for reliably classifying the topographies and that there is a large potential to improve the ITR by optimizing the trial length. The robust performance and the simple stimulation setup suggest that this approach is a prime candidate for applications on desktop and tablet computers.

  15. Evaluating Letter Recognition, Flicker Fusion, and the Talbot-Plateau Law using Microsecond-Duration Flashes

    Science.gov (United States)

    Greene, Ernest

    2015-01-01

    Four experiments examined the ability of respondents to identify letters that were displayed on an LED array with flashes lasting little more than a microsecond. The first experiment displayed each letter with a single, simultaneous flash of all the dots forming the letter and established the relation of flash intensity to the probability of letter identification. The second experiment displayed the letters with multiple flashes at different frequencies to determine the probability that the sequence of flashes would be perceived as fused. The third experiment displayed the letters at a frequency that was above the flicker-fusion frequency, varying flash intensity to establish the amount needed to elicit a given probability of letter identification. The fourth experiment displayed each letter twice, once at a frequency where no flicker was perceived and also with steady light emission. The intensity of each flash was fixed and the steady intensity was varied; respondents were asked to judge whether the fused-flicker display and the steady display appeared to be the same brightness. Steady intensity was about double the average flash intensity where the two conditions were perceived as being equal in brightness. This is at odds with Talbot-Plateau law, which predicts that these two values should be equal. The law was formulated relative to a flash lasting half of each period, so it is surprising that it comes this close to being correct where the flash occupies only a millionth of the total period. PMID:25875652

  16. Protection of flickers and higher harmonics produced from static power supply

    International Nuclear Information System (INIS)

    Masuda, M.

    1974-01-01

    There are two problems when the power source for proton synchrotrons is connected directly to a power line. One is voltage flicker, which comes from the large power swing of pulse load, that is main ring magnets in the present case. The other is the higher harmonic current generated by large converters. These problems can be said as a sort of pollution. The latter is very serious. The A.C. harmonic current emanates from thyristors or mercury converters, and even a slight amount of it propagates over 50 km distance on a power grid, and finally stimulates local resonance with capacitors which are equipped for improving power factor at factories. The main function of flicker suppressors is the compensation of reactive power, not real power. There is nothing to do with the real power, as it is small, and always it can be neglected. Therefore it can be said that this system is reactive power compensator as well as the flicker suppressor. There are three typical compensators. One is saturable reactors. The principle is conventional. The advantage of this type is the continuous and complete compensation of reactive power. The second type is capacitor steps. The response is fast, but the disadvantage of this type is step compensation instead of continuous compensation. The third type is the compensators using thyristors. The principle of the compensators is elegant and sophisticated. But this is rather expensive. (Tai, I.)

  17. Electroretinographic assessment of rod- and cone-mediated bipolar cell pathways using flicker stimuli in mice

    Science.gov (United States)

    Tanimoto, Naoyuki; Sothilingam, Vithiyanjali; Kondo, Mineo; Biel, Martin; Humphries, Peter; Seeliger, Mathias W.

    2015-01-01

    Mouse full-field electroretinograms (ERGs) are dominated by responses of photoreceptors and depolarizing (ON-) bipolar cells, but not much of hyperpolarizing (OFF-) bipolar cells under conventional recording conditions. Here we investigate a novel ERG protocol in mice for functional assessment of the major ON- and OFF-bipolar cell pathways using flicker stimuli for a high luminance with varying frequency up to 30 Hz. Wild-type (WT) and functionally specific transgenic mice (Cnga3-/-, no cone photoreceptor function; rho-/-, no rod photoreceptor function; mGluR6-/-, no ON-bipolar cell function) were examined. The Cnga3-/- flicker ERG was similar to the WT flicker ERG at very low stimulus frequencies, whereas ERGs were comparable between WT and rho-/- mice at 5 Hz and above. Between 5 and 15 Hz, ERGs in mGluR6-/- mice differed in configuration and amplitude from those in WT and rho-/- mice; in contrast, response amplitudes above 15 Hz were comparable among WT, rho-/- and mGluR6-/- mice. In summary, we found three frequency ranges with these conditions that are dominated by activity in the rod pathways (below 5 Hz), cone ON-pathway (between 5 and 15 Hz), and cone OFF-pathway (above 15 Hz) that enables a quick overview of the functionality of the major bipolar cell pathways. PMID:26029863

  18. HyperCube: A Small Lensless Position Sensing Device for the Tracking of Flickering Infrared LEDs

    Directory of Open Access Journals (Sweden)

    Thibaut Raharijaona

    2015-07-01

    Full Text Available An innovative insect-based visual sensor is designed to perform active marker tracking. Without any optics and a field-of-view of about 60°, a novel miniature visual sensor is able to locate flickering markers (LEDs with an accuracy much greater than the one dictated by the pixel pitch. With a size of only 1 cm3 and a mass of only 0.33 g, the lensless sensor, called HyperCube, is dedicated to 3D motion tracking and fits perfectly with the drastic constraints imposed by micro-aerial vehicles. Only three photosensors are placed on each side of the cubic configuration of the sensing device, making this sensor very inexpensive and light. HyperCube provides the azimuth and elevation of infrared LEDs flickering at a high frequency (>1 kHz with a precision of 0.5°. The minimalistic design in terms of small size, low mass and low power consumption of this visual sensor makes it suitable for many applications in the field of the cooperative flight of unmanned aerial vehicles and, more generally, robotic applications requiring active beacons. Experimental results show that HyperCube provides useful angular measurements that can be used to estimate the relative position between the sensor and the flickering infrared markers.

  19. Comparing the detection and agreement of parapapillary atrophy progression using digital optic disk photographs and alternation flicker.

    Science.gov (United States)

    VanderBeek, Brian L; Smith, Scott D; Radcliffe, Nathan M

    2010-09-01

    Parapapillary atrophy (PPA) progression has been associated with progressive glaucoma, but has proven to be difficult to assess clinically. We compared inter- and intra-observer agreement using a novel automated alternation flicker technology and side-by-side digital photography inspection for the evaluation of PPA progression. Consecutive patients with serial digital optic nerve photographs at least 1 year apart were included. Two graders (NR, BV) masked to image chronology assessed a set of photographs for progressive PPA using predefined criteria based on reference photographs containing mild, moderate, extensive or no PPA progression. At a separate session, the graders evaluated photographs using alternation flicker (EyeIC, Narberth, PA, USA) applying the same criteria. The order of patients and technique was randomized. Graders then assessed the same set of flickers and photographs a second time with the order of presentation reversed. The main outcome measure was the assessment of progressive PPA as identified by alternation flicker and digital photography inspection. Inter- and intra-observer agreement using each technique was assessed using the kappa statistic. A bootstrap method for comparing correlated kappa coefficients was used to assess statistical significance. Serial photographs from 131 eyes of 68 patients were evaluated. Both graders identified significantly more cases of PPA progression using flicker compared to photography (27-34% vs 8-13%; both pflicker was better than using photographs (kappa=0.52 vs 0.18, p=0.02). Intra-observer agreement was similar for both graders (photos: kappa=0.58 vs 0.57, p=0.97; flicker: kappa=0.61 vs 0.70, p=0.37). When progression was assessed by the number of progressive quadrants identified by each grader using a weighted kappa statistic, flicker inter-observer agreement was still moderate (kappa=0.45) and significantly better (p=0.01) than photography, which showed poor agreement (kappa=0.15). Intra

  20. Factors Affecting Mydriasis-Free Flicker ERGs Recorded With Real-Time Correction for Retinal Illuminance: Study of 150 Young Healthy Subjects.

    Science.gov (United States)

    Kato, Kumiko; Kondo, Mineo; Nagashima, Ryunosuke; Sugawara, Asako; Sugimoto, Masahiko; Matsubara, Hisashi; McCulloch, Daphne L; Ikesugi, Kengo

    2017-10-01

    A small, full-field flicker electroretinogram (ERG) recording system was recently developed to record flicker ERGs without mydriasis (RETeval). The device delivers a stimulus with constant retinal illuminance by adjusting the retinal luminance to compensate for changes in the pupillary area. The purpose of this study was to determine what factors affect the fundamental components of the flicker ERGs recorded by RETeval in young healthy subjects. Flicker ERGs were recorded with the RETeval system from 150 eyes of 150 young healthy subjects (age, 20-29 years). Univariate and multivariate linear regression analyses were performed to identify the factors that affected the implicit times and amplitudes of the fundamental component of the flicker ERGs. The independent variables included age, sex, refractive error, axial length, and pupillary area. Multivariate regression analyses indicated that a longer axial length (P = 0.03) and larger pupillary area (P = 0.008) were independent factors that were significantly associated with longer implicit times of the fundamental component of the flicker ERGs. Multivariate regression analyses also showed that the female sex (P = 0.03) was an independent factor, which was significantly associated with larger amplitude fundamental component of the flicker ERGs. These results indicate that the fundamental components of the RETeval flicker ERGs are significantly affected by the axial length, pupillary area, and sex of young healthy subjects. The results also suggest that it would be better to compensate for the Stiles-Crawford effect when flicker ERGs are recorded with natural pupils.

  1. Human Visual Cortex Responses to Rapid Cone and Melanopsin-Directed Flicker.

    Science.gov (United States)

    Spitschan, Manuel; Datta, Ritobrato; Stern, Andrew M; Brainard, David H; Aguirre, Geoffrey K

    2016-02-03

    Signals from cones are recombined in postreceptoral channels [luminance, L + M; red-green, L - M; blue-yellow, S - (L + M)]. The melanopsin-containing retinal ganglion cells are also active at daytime light levels and recent psychophysical results suggest that melanopsin contributes to conscious vision in humans. Here, we measured BOLD fMRI responses to spectral modulations that separately targeted the postreceptoral cone channels and melanopsin. Responses to spatially uniform (27.5° field size, central 5° obscured) flicker at 0.5, 1, 2, 4, 8, 16, 32, and 64 Hz were recorded from areas V1, V2/V3, motion-sensitive area MT, and the lateral occipital complex. In V1 and V2/V3, higher temporal sensitivity was observed to L + M + S (16 Hz) compared with L - M flicker (8 Hz), consistent with psychophysical findings. Area MT was most sensitive to rapid (32 Hz) flicker of either L + M + S or L - M. We found S cone responses only in areas V1 and V2/V3 (peak frequency: 4-8 Hz). In addition, we studied an L + M modulation and found responses that were effectively identical at all temporal frequencies to those recorded for the L + M + S modulation. Finally, we measured the cortical response to melanopsin-directed flicker and compared this response with control modulations that addressed stimulus imprecision and the possibility of stimulation of cones in the shadow of retinal blood vessels (penumbral cones). For our stimulus conditions, melanopsin flicker did not elicit a cortical response exceeding that of the control modulations. We note that failure to control for penumbral cone stimulation could be mistaken for a melanopsin response. The retina contains cone photoreceptors and ganglion cells that contain the photopigment melanopsin. Cones provide brightness and color signals to visual cortex. Melanopsin influences circadian rhythm and the pupil, but its contribution to cortex and perception is less clear. We measured the response of human visual cortex with fMRI using

  2. Electrical flicker-noise generated by filling and emptying of impurity states in injectors of quantum-cascade lasers

    International Nuclear Information System (INIS)

    Yamanishi, Masamichi; Hirohata, Tooru; Hayashi, Syohei; Fujita, Kazuue; Tanaka, Kazunori

    2014-01-01

    Free running line-widths (>100 kHz), much broader than intrinsic line-widths ∼100 Hz, of existing quantum-cascade lasers are governed by strong flicker frequency-noise originating from electrical flicker noise. Understanding of microscopic origins of the electrical flicker noises in quantum-cascade lasers is crucially important for the reduction of strength of flicker frequency-noise without assistances of any type of feedback schemes. In this article, an ad hoc model that is based on fluctuating charge-dipoles induced by electron trappings and de-trappings at indispensable impurity states in injector super-lattices of a quantum-cascade laser is proposed, developing theoretical framework based on the model. The validity of the present model is evaluated by comparing theoretical voltage-noise power spectral densities based on the model with experimental ones obtained by using mid-infrared quantum-cascade lasers with designed impurity-positioning. The obtained experimental results on flicker noises, in comparison with the theoretical ones, shed light on physical mechanisms, such as the inherent one due to impurity states in their injectors and extrinsic ones due to surface states on the ridge-walls and due to residual deep traps, for electrical flicker-noise generation in existing mid-infrared quantum-cascade lasers. It is shown theoretically that quasi-delta doping of impurities in their injectors leads to strong suppression of electrical flicker noise by minimization of the dipole length at a certain temperature, for instance ∼300 K and, in turn, is expected to result in substantial narrowing of the free running line-width down below 10 kHz

  3. Role of neuronal nitric oxide synthase in regulating retinal blood flow during flicker-induced hyperemia in cats.

    Science.gov (United States)

    Yoshioka, Takafumi; Nagaoka, Taiji; Song, Youngseok; Yokota, Harumasa; Tani, Tomofumi; Yoshida, Akitoshi

    2015-05-01

    To investigate how neuronal nitric oxide synthase (nNOS) contributes to regulation of the retinal circulation during rest and flicker stimulation in cats. Using laser Doppler velocimetry, we measured the vessel diameter and blood velocity simultaneously and calculated the retinal blood flow (RBF) in feline first-order retinal arterioles. After intravitreal injections of Nω-Nitro-L-arginine methyl ester (L-NAME), a nonselective NOS inhibitor, and Nω-propyl-L-arginine (L-NPA), a selective nNOS inhibitor, we continuously monitored the retinal circulation without any perturbations for 2 hours. We then examined the changes in the RBF in response to 16-Hz flicker stimuli for 3 minutes at 2 hours after intravitreal injection of phosphate-buffered saline (PBS) as a control, L-NAME, L-NPA, and thromboxane A2 (TXA2) analogue U46619 as a basal tone-adjusted control. After intravitreal injection of L-NAME and L-NPA, the baseline RBF decreased gradually in a dose-dependent manner. In the PBS group, the RBF increased gradually and reached a maximal level after 2 to 3 minutes of flicker stimuli. After 3 minutes of 16-Hz flicker stimuli, the RBF increased by 53.5% ± 3.4% compared with baseline. In the L-NAME and L-NPA groups, the increases in RBF during flicker stimulation were attenuated significantly compared with the PBS group. In the TXA2 group, the reduction in the flicker-induced increase in RBF was comparable to that in the PBS group. The current results suggested that increased RBF in response to flicker stimulation may be mediated by nitric oxide (NO) production via nNOS activation.

  4. Rod-driven OFF pathway responses in the distal retina: dark-adapted flicker electroretinogram in mouse.

    Science.gov (United States)

    Lei, Bo

    2012-01-01

    The rodent retina does not exhibit a positive OFF-response in the electroretinogram (ERG), which makes it difficult to evaluate its OFF-pathway functions in vivo. We studied the rod-driven OFF pathway responses by using a dark-adapted 10-Hz flicker ERG procedure in mouse. Conventional ERGs and 10-Hz dark-adapted flicker ERGs were obtained in wild-type mice (C57BL/6), in mice with pure rod (cpfl1) or pure cone (rho(-/-)) function, and in nob1 mice which have a selective ON-pathway defect. To isolate the response from ON or OFF pathway, glutamate analogs 2-amino-4-phosphobutyric acid (APB, an ON pathway blocker) and cis-2, 3-piperidine-dicarboxylic acid (PDA, an OFF pathway blocker), were injected intravitreally. The amplitude-intensity profile of the dark-adapted 10-Hz flicker ERG in the wild-type mice exhibits two peaks at middle and high light intensities. The two peaks represent rod- and cone-driven responses respectively. In APB-treated C57BL/6 mice and in nob1 mice, the dark-adapted ERG b-waves were absent. However, both rod- and cone-driven OFF pathway responses were evident with flicker ERG recording. At middle light intensities that activate only rod system, the flicker ERG responses in saline-injected nob1 mice were similar to those in APB-injected cpfl1 mice and wild-type mice. These responses are sensitive to PDA. The amplitudes of these rod-driven OFF pathway responses were approximately 20% of the total rod-driven flicker ERG responses. We demonstrate that the rod-OFF bipolar cell pathway is functional in the outer retina. The dark-adapted flicker ERG is practical for the evaluation of rod- and cone-driven responses, and the residual OFF pathway signals in subjects with ON pathway defects.

  5. The impact of candle burning during All Saints' Day ceremonies on ambient alkyl-substituted benzene concentrations.

    Science.gov (United States)

    Olszowski, Tomasz; Kłos, Andrzej

    2013-11-01

    Research findings concerning benzene, toluene, ethylobenzene, meta-, para- and ortho-xylene as well as styrene (BTEXS) emission at public cemeteries during All Saints' Day are presented here. Tests were carried out at town-located cemeteries in Opole and Grodków (southern Poland) and, as a benchmark, at the centres of those same towns. The purpose of the study was to estimate BTEXS emissions caused by the candle burning and, equally important to examine, whether emissions generated by the tested sources were similar to the BTEXS emissions generated by road transport. During the festive period, significant increases in benzene concentrations, by 200 % and 144 %, were noted at the cemeteries in Opole and Grodków, as well as in toluene, by 366 % and 342 %, respectively. Styrene concentrations also increased. It was demonstrated that the ratio of toluene to benzene concentrations from emissions caused by the burning candles are comparable to the ratio established for transportation emissions.

  6. Periodontal Manifestations of Chronic Atypical Neutrophilic Dermatosis With Lipodystrophy and Elevated Temperature (CANDLE) Syndrome in an 11 Year Old Patient

    OpenAIRE

    McKenna, Gerald J.; Ziada, Hassan M.

    2015-01-01

    Introduction: Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) is an auto inflammatory syndrome caused by an autosomal recessive gene mutation. This very rare syndrome has been reported in only 14 patients worldwide. A number of clinical signs have been reported including joint contractures, muscle atrophy, microcytic anaemia, and panniculitis-induced childhood lipodystrophy. Further symptoms include recurrent fevers, purpuric skin lesions, periorb...

  7. Flicker and thermal noise in an n-channel underlap DG FinFET in a weak inversion region

    International Nuclear Information System (INIS)

    Pati, Sudhansu Kumar; Pardeshi, Hemant; Raj, Godwin; Sarkar, Chandan Kumar; Mohankumar, N

    2013-01-01

    We propose an analytical model for drain current and inversion charge in the subthreshold region for an underlap DG FinFET by using the minimum channel potential method, i.e., the virtual source. The flicker and thermal noise spectral density models are also developed using these charge and current models expression. The model is validated with already published experimental results of flicker noise for DG FinFETs. For an ultrathin body, the degradation of effective mobility and variation of the scattering parameter are considered. The effect of device parameters like gate length L g and underlap length L un on both flicker and thermal noise spectral densities are also analyzed. Increasing L g and L un , increases the effective gate length, which reduces drain current, resulting in decreased flicker and thermal noise density. A decrease of flicker noise is observed for an increase of frequency, which indicates that the device can be used for wide range of frequency applications. (semiconductor devices)

  8. Optimal Tuning of Multivariable Disturbance-Observer-Based Control for Flicker Mitigation Using Individual Pitch Control of Wind Turbine

    DEFF Research Database (Denmark)

    Raja, Muhammad Imran; Hussain, Dil muhammed Akbar; Soltani, Mohsen

    2017-01-01

    Multivariable disturbance accommodated observer based control (DOBC) scheme is presented to mitigate loads generated due to wind shear and tower shadow using individual blade pitch for above-rated wind speed condition of wind turbine. Wind shear and tower shadow add flickers as 1p, 3p, 6p and so on......, (p is the rotor rotational frequency) for three-bladed wind turbine. Novel DOBC with individual pitch control (IPC) to mitigate the flickers is presented and linear state-space model of wind turbine with tower dynamics is developed. The proposed controller is tuned using optimal control theory...... density of generator speed, drive-train torsion and tower fore-aft moment shows better mitigation to the flickers by proposed controller as compared with proportional–integral (PI) and disturbance accommodation control (DAC) with collective pitch control. Furthermore, it shows less degradation...

  9. Fast entrainment of human electroencephalogram to a theta-band photic flicker during successful memory encoding

    Directory of Open Access Journals (Sweden)

    Naoyuki eSato

    2013-05-01

    Full Text Available Theta band power (4-8Hz in the scalp electroencephalogram (EEG is thought to be stronger during memory encoding for subsequently remembered items than for forgotten items. According to simultaneous EEG-functional magnetic resonance imaging (fMRI measurements, the memory-dependent EEG theta is associated with multiple regions of the brain. This suggests that the multiple regions cooperate with EEG theta synchronization during successful memory encoding. However, a question still remains: What kind of neural dynamic organizes such a memory-dependent global network? In this study, the modulation of the EEG theta entrainment property during successful encoding was hypothesized to lead to EEG theta synchronization among a distributed network. Then, a transient response of EEG theta to a theta-band photic flicker with a short duration was evaluated during memory encoding. In the results, flicker-induced EEG power increased and decreased with a time constant of several hundred milliseconds following the onset and the offset of the flicker, respectively. Importantly, the offset response of EEG power was found to be significantly decreased during successful encoding. Moreover, the offset response of the phase locking index was also found to associate with memory performance. According to computational simulations, the results are interpreted as a smaller time constant (i.e., faster response of a driven harmonic oscillator rather than a change in the spontaneous oscillatory input. This suggests that the fast response of EEG theta forms a global EEG theta network among memory-related regions during successful encoding, and it contributes to a flexible formation of the network along the time course.

  10. Stellar granulation as the source of high-frequency flicker in Kepler light curves

    Energy Technology Data Exchange (ETDEWEB)

    Cranmer, Steven R.; Saar, Steven H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bastien, Fabienne A.; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States)

    2014-02-01

    A large fraction of cool, low-mass stars exhibit brightness fluctuations that arise from a combination of convective granulation, acoustic oscillations, magnetic activity, and stellar rotation. Much of the short-timescale variability takes the form of stochastic noise, whose presence may limit the progress of extrasolar planet detection and characterization. In order to lay the groundwork for extracting useful information from these quasi-random signals, we focus on the origin of the granulation-driven component of the variability. We apply existing theoretical scaling relations to predict the star-integrated variability amplitudes for 508 stars with photometric light curves measured by the Kepler mission. We also derive an empirical correction factor that aims to account for the suppression of convection in F-dwarf stars with magnetic activity and shallow convection zones. So that we can make predictions of specific observational quantities, we performed Monte Carlo simulations of granulation light curves using a Lorentzian power spectrum. These simulations allowed us to reproduce the so-called flicker floor (i.e., a lower bound in the relationship between the full light-curve range and power in short-timescale fluctuations) that was found in the Kepler data. The Monte Carlo model also enabled us to convert the modeled fluctuation variance into a flicker amplitude directly comparable with observations. When the magnetic suppression factor described above is applied, the model reproduces the observed correlation between stellar surface gravity and flicker amplitude. Observationally validated models like these provide new and complementary evidence for a possible impact of magnetic activity on the properties of near-surface convection.

  11. Fast entrainment of human electroencephalogram to a theta-band photic flicker during successful memory encoding

    Science.gov (United States)

    Sato, Naoyuki

    2013-01-01

    Theta band power (4–8 Hz) in the scalp electroencephalogram (EEG) is thought to be stronger during memory encoding for subsequently remembered items than for forgotten items. According to simultaneous EEG-functional magnetic resonance imaging (fMRI) measurements, the memory-dependent EEG theta is associated with multiple regions of the brain. This suggests that the multiple regions cooperate with EEG theta synchronization during successful memory encoding. However, a question still remains: What kind of neural dynamic organizes such a memory-dependent global network? In this study, the modulation of the EEG theta entrainment property during successful encoding was hypothesized to lead to EEG theta synchronization among a distributed network. Then, a transient response of EEG theta to a theta-band photic flicker with a short duration was evaluated during memory encoding. In the results, flicker-induced EEG power increased and decreased with a time constant of several hundred milliseconds following the onset and the offset of the flicker, respectively. Importantly, the offset response of EEG power was found to be significantly decreased during successful encoding. Moreover, the offset response of the phase locking index was also found to associate with memory performance. According to computational simulations, the results are interpreted as a smaller time constant (i.e., faster response) of a driven harmonic oscillator rather than a change in the spontaneous oscillatory input. This suggests that the fast response of EEG theta forms a global EEG theta network among memory-related regions during successful encoding, and it contributes to a flexible formation of the network along the time course. PMID:23730282

  12. Stellar granulation as the source of high-frequency flicker in Kepler light curves

    International Nuclear Information System (INIS)

    Cranmer, Steven R.; Saar, Steven H.; Bastien, Fabienne A.; Stassun, Keivan G.

    2014-01-01

    A large fraction of cool, low-mass stars exhibit brightness fluctuations that arise from a combination of convective granulation, acoustic oscillations, magnetic activity, and stellar rotation. Much of the short-timescale variability takes the form of stochastic noise, whose presence may limit the progress of extrasolar planet detection and characterization. In order to lay the groundwork for extracting useful information from these quasi-random signals, we focus on the origin of the granulation-driven component of the variability. We apply existing theoretical scaling relations to predict the star-integrated variability amplitudes for 508 stars with photometric light curves measured by the Kepler mission. We also derive an empirical correction factor that aims to account for the suppression of convection in F-dwarf stars with magnetic activity and shallow convection zones. So that we can make predictions of specific observational quantities, we performed Monte Carlo simulations of granulation light curves using a Lorentzian power spectrum. These simulations allowed us to reproduce the so-called flicker floor (i.e., a lower bound in the relationship between the full light-curve range and power in short-timescale fluctuations) that was found in the Kepler data. The Monte Carlo model also enabled us to convert the modeled fluctuation variance into a flicker amplitude directly comparable with observations. When the magnetic suppression factor described above is applied, the model reproduces the observed correlation between stellar surface gravity and flicker amplitude. Observationally validated models like these provide new and complementary evidence for a possible impact of magnetic activity on the properties of near-surface convection.

  13. Cancer Driver Log (CanDL): Catalog of Potentially Actionable Cancer Mutations.

    Science.gov (United States)

    Damodaran, Senthilkumar; Miya, Jharna; Kautto, Esko; Zhu, Eliot; Samorodnitsky, Eric; Datta, Jharna; Reeser, Julie W; Roychowdhury, Sameek

    2015-09-01

    Massively parallel sequencing technologies have enabled characterization of genomic alterations across multiple tumor types. Efforts have focused on identifying driver mutations because they represent potential targets for therapy. However, because of the presence of driver and passenger mutations, it is often challenging to assign the clinical relevance of specific mutations observed in patients. Currently, there are multiple databases and tools that provide in silico assessment for potential drivers; however, there is no comprehensive resource for mutations with functional characterization. Therefore, we created an expert-curated database of potentially actionable driver mutations for molecular pathologists to facilitate annotation of cancer genomic testing. We reviewed scientific literature to identify variants that have been functionally characterized in vitro or in vivo as driver mutations. We obtained the chromosome location and all possible nucleotide positions for each amino acid change and uploaded them to the Cancer Driver Log (CanDL) database with associated literature reference indicating functional driver evidence. In addition to a simple interface, the database allows users to download all or selected genes as a comma-separated values file for incorporation into their own analysis pipeline. Furthermore, the database includes a mechanism for third-party contributions to support updates for novel driver mutations. Overall, this freely available database will facilitate rapid annotation of cancer genomic testing in molecular pathology laboratories for mutations. Copyright © 2015 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  14. Safety Analysis of Pb-208 Cooled 800 MWt Modified CANDLE Reactors

    Science.gov (United States)

    Su'ud, Zaki; Widiawati, Nina; Sekimoto, H.; Artoto, A.

    2017-01-01

    Safely analysis of 800MWt Pb-208 cooled fast reactors with natural Uranium as fuel cycle input employing axial-radial combined Modiified CANDLE burnup scheme has been performed. The analysis of unprotected loss of flow(ULOF) and unprotected rod run-out transient overpower (UTOP) are discussed. Some simulations for 800 MWt Pb-208 cooled fast reactors has been performed and the results show that the reactor can anticipate complete pumping failure inherently by reducing power through reactivity feedback and remove the rest of heat through natural circulations. Compared to the Pb-nat cooled long life Fast Reactors, Pb-208 cooled reactors have smaller Doppler but higher coolant density reactivity coefficient. In the UTOP accident case the analysis has been performed against external reactivity up to 0.003dk/k. And for ULOHS case it is assumed that the secondary cooling system has broken. During all accident the cladding temperature is the most critical. Especially for the case of UTOP accident. In addition the steam generator design has also consider excess power which may reach 50% extra during severe UTOP case..

  15. Self-organized complex space charge configurations at the origin of flicker noise

    CERN Document Server

    Popescu, S; Sanduloviciu, M

    2003-01-01

    Based on experimental results obtained from a plasma diode we explain the fluctuations of the voltage supported by a non-linear gaseous conductor by the dynamical behavior of spatiotemporal patterns, in the form of moving double layers, formed after self-organization. Such phenomena appear when the system is subjected to an external constraint that creates and maintains a local gradient of electron kinetic energy. The described phenomenology suggests a plausible explanation for the appearance of flicker noise also in other physical systems, as for example semiconductors and, implicitly, offers a new model for the so-called self-organized criticality concept.

  16. Boson peak, flickering noise, backscattering processes and radiative transfer in random media

    International Nuclear Information System (INIS)

    Budak, V.P.; Veklenko, B.A.

    2011-01-01

    The method of matrix Green's functions in the classical theory of electromagnetic waves is stated. This method allows to obtain a closed equation system in the presence of the random media for the calculation both coherent, and incoherent (fluctuating) components of radiation. The density and heterogeneity of scattering media can be arbitrary. The coherent channel is calculated independently. The fluctuating radiation distribution in the medium is developed initially by an interference pattern generated by the coherent channel. The limitations of the processes speed are absent. The theory embraces such phenomena as the boson peak, flickering noise, memory effect, backscattering processes and also conventional radiative transfer equation and Fresnel's formulae.

  17. Flicker noise of magneto-dependent component of SHF power of resonator with epitaxial HTSC film

    International Nuclear Information System (INIS)

    Bobyl', A.V.; Suris, R.A.; Fomin, N.V.

    1996-01-01

    The methodology of studies on the flicker noise (FN) of magneto-dependent component of the SHF power of the resonator with HTSC film is described. The methodology consists in registration of the FN low-frequency intensity of the magneto-dependent component of the SHF power of the resonator. The analysis was carried out for radio-frequency range. Dependence of the absorbed power value, its magneto-dependent part and the FN intensity on the temperature is obtained. The proposed method is effective by studies of the FN sources in the neighborhood and essentially lower T kr

  18. Self-organized complex space charge configurations at the origin of flicker noise

    International Nuclear Information System (INIS)

    Popescu, S.; Lozneanu, E.; Sanduloviciu, M.

    2003-01-01

    Based on experimental results obtained from a plasma diode we explain the fluctuations of the voltage supported by a non-linear gaseous conductor by the dynamical behavior of spatiotemporal patterns, in the form of moving double layers, formed after self-organization. Such phenomena appear when the system is subjected to an external constraint that creates and maintains a local gradient of electron kinetic energy. The described phenomenology suggests a plausible explanation for the appearance of flicker noise also in other physical systems, as for example semiconductors and, implicitly, offers a new model for the so-called self-organized criticality concept

  19. An Examination of the Relationship between Visual Fatigue Symptoms with Flicker Value Variations in Video Display Terminal Users

    Directory of Open Access Journals (Sweden)

    Ehsanollah Habibi

    2015-01-01

    Full Text Available In most sensitive occupations such as nuclear, military and chemical industries closed circuit systems and visual display terminals (VDTs are used to carefully control and assess sensitive processes. Visual fatigue is one of the factors decreasing accuracy and concentration in operators causing faulty perception. This study aimed to find out a relationship between visual fatigue symptoms (VFS of Flicker value variations in video display terminal (VDT operators. This cross-sectional study, conducted in 2011, aimed to examine visual fatigue and determine the relationship between its symptoms and visual flicker value changes in 248 operators of VDTs in several occupations. The materials used in this study were a visual fatigue questionnaire of VDTs and a VFM-90.1 device. Visual fatigue was measured in two stages (prior to beginning to work and 60 min later. The data were analyzed by SPSS11.5, using descriptive statistics, paired t-test, simple and multiple linear regressions, correlation and recognition coefficients. Then regression equations of changes in flicker value depending on the changes in the main domains and the changes in final score before the questionnaire were obtained. Paired t-test indicated significant differences in the mean score of visual fatigue symptoms and the mean score of flicker value between the two stages, respectively (P ≤ 0.001. Simple and multiple regressions of flicker value variations, for the last visual fatigue changes in questionnaire score and the four main domains of the questionnaire were obtained R2 = 0.851 and R2 = 0.853, respectively. Correlation coefficient in the above tests indicated reverse and significant relationships among flicker value changes with changes in questionnaire score and visual fatigue symptoms. Diagnosing the first symptoms of visual fatigue could be an appropriate warning for VDTs operators in sensitive occupations to react suitably, in behavior and management, to control or treat

  20. Flickering characteristics and temperature field of premixed methane/air flame under the influence of co-flow

    International Nuclear Information System (INIS)

    Fujisawa, Nobuyuki; Abe, Takao; Yamagata, Takayuki; Tomidokoro, Hirofumi

    2014-01-01

    Highlights: • Flickering characteristics and temperature field of premixed methane/air flame are studied in co-flow. • The temperature is measured by improved flame reaction technique by correcting the number density of metal atoms. • The temperature calibration is conducted by sodium D-line reversal method. • The oscillation amplitude of flame decreases and the frequency increases with co-flow velocity. • The oscillation amplitude increases with equivalence ratio. - Abstract: The flickering characteristics and the temperature field of an axisymmetric premixed methane/air flame under the influence of co-flow are studied experimentally using the image analysis and the flame reaction technique. The premixed flame is visualized by the alkali metal solution of sodium (Na) for characterizing the flickering characteristics. The temperature measurement of the flame is carried out using the flame reaction technique combined with the relationship between the local intensity of the flame and the temperature from the sodium D-line reversal method, and the influence of the number density distribution of Na on the measured temperature field is corrected by the measurement integrated analysis of the flame with the iterative procedure. This technique is validated by the local temperature measurement in the steady flame under the influence of co-flow using the thermocouple calibrated by the sodium D-line reversal method. The flame visualization and temperature measurement in the flickering flame of the premixed methane/air flame indicates that the flame contour and the temperature field oscillate periodically with the flickering frequency due to the Kelvin–Helmholtz instability of the flame. The oscillation amplitude decreases and the frequency increases gradually with the co-flow velocity increases similar to the observation in the diffusion flame in literature, while the oscillation amplitude grows with the equivalence ratio increases. These changes in the flickering

  1. Application of a single-flicker online SSVEP BCI for spatial navigation.

    Science.gov (United States)

    Chen, Jingjing; Zhang, Dan; Engel, Andreas K; Gong, Qin; Maye, Alexander

    2017-01-01

    A promising approach for brain-computer interfaces (BCIs) employs the steady-state visual evoked potential (SSVEP) for extracting control information. Main advantages of these SSVEP BCIs are a simple and low-cost setup, little effort to adjust the system parameters to the user and comparatively high information transfer rates (ITR). However, traditional frequency-coded SSVEP BCIs require the user to gaze directly at the selected flicker stimulus, which is liable to cause fatigue or even photic epileptic seizures. The spatially coded SSVEP BCI we present in this article addresses this issue. It uses a single flicker stimulus that appears always in the extrafoveal field of view, yet it allows the user to control four control channels. We demonstrate the embedding of this novel SSVEP stimulation paradigm in the user interface of an online BCI for navigating a 2-dimensional computer game. Offline analysis of the training data reveals an average classification accuracy of 96.9±1.64%, corresponding to an information transfer rate of 30.1±1.8 bits/min. In online mode, the average classification accuracy reached 87.9±11.4%, which resulted in an ITR of 23.8±6.75 bits/min. We did not observe a strong relation between a subject's offline and online performance. Analysis of the online performance over time shows that users can reliably control the new BCI paradigm with stable performance over at least 30 minutes of continuous operation.

  2. Relation of retinal blood flow and retinal oxygen extraction during stimulation with diffuse luminance flicker

    Science.gov (United States)

    Palkovits, Stefan; Lasta, Michael; Told, Reinhard; Schmidl, Doreen; Werkmeister, René; Cherecheanu, Alina Popa; Garhöfer, Gerhard; Schmetterer, Leopold

    2015-01-01

    Cerebral and retinal blood flow are dependent on local neuronal activity. Several studies quantified the increase in cerebral blood flow and oxygen consumption during activity. In the present study we investigated the relation between changes in retinal blood flow and oxygen extraction during stimulation with diffuse luminance flicker and the influence of breathing gas mixtures with different fractions of O2 (FiO2; 100% 15% and 12%). Twenty-four healthy subjects were included. Retinal blood flow was studied by combining measurement of vessel diameters using the Dynamic Vessel Analyser with measurements of blood velocity using laser Doppler velocimetry. Oxygen saturation was measured using spectroscopic reflectometry and oxygen extraction was calculated. Flicker stimulation increased retinal blood flow (57.7 ± 17.8%) and oxygen extraction (34.6 ± 24.1%; p flicker–induced retinal haemodynamic changes. The present study indicates that at a comparable increase in blood flow the increase in oxygen extraction in the retina is larger than in the brain. During systemic hyperoxia the blood flow and oxygen extraction responses to neural stimulation are augmented. The underlying mechanism is unknown. PMID:26672758

  3. Colors of the pulsations and flickering of Sy Cancri during outburst

    International Nuclear Information System (INIS)

    Middleditch, J.; Cordova, F.A.

    1982-01-01

    The spectra of the short period (approx.30 s) oscillations and flickering of the dwarf nova Sy Cnc have been determined by simultaneous measuring the optical flux in three broad, contiguous spectral bands during an optical outburst of the star. The spectrum of the oscillation rises too rapidly toward short wavelengths to be consistent with any simple thermal model. The colors of the flickering are even more extreme (i.e., more ultraviolet) than those of the pulsations. No timing differences were detected to a fraction of a second between the ultraviolet (U), cyan (B+V, or C) and red (R, to 9000 A) bands of the pulsations; thus, the optical oscillations appear to arise from a single physical location in the binary system. Without a detailed study of a more complicated class of models, which may include recombination radiation from H I, He I, and He II in addition to a thermal model, it is impossible to assign a temperature to the oscillations and thereby determine whether they are produced directly on the white dwarf or in the accretion disk

  4. Two Visual Training Paradigms Associated with Enhanced Critical Flicker Fusion Threshold

    Directory of Open Access Journals (Sweden)

    Tianyou Zhou

    2016-10-01

    Full Text Available Critical flicker fusion thresholds (CFFT describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision training approaches (ULTIMEYES and directional dot motion compared to an active control group trained on Sudoku. The three training paradigms were compared on their effectiveness for altering Critical Flicker Fusion Threshold (CFFT. Directional dot motion and ULTIMEYES training resulted in significant improvement in CFFT, while the Sudoku group did not yield significant improvement. This finding indicates that the two motion-related conditions (dot motion and ULTIMEYES are effective methods for studying the role of low-level visual motion training on plasticity of higher order perceptual tasks, e.g. CFFT. The results and implications for potential future vision-based brain plasticity research involving high-order cognitive processes such as reading ability are discussed.

  5. 75 FR 27733 - Agency Information Collection Activities; Proposed Collection; Comment Request; Standard for the...

    Science.gov (United States)

    2010-05-18

    ... Fabrics Act (``FFA''), 15 U.S.C. 1193, to reduce unreasonable risks of burn injuries and deaths from fires... mattress pad will resist ignition from a smoldering cigarette. The standard requires manufacturers to... related to mattress fires, particularly those ignited by open flame sources such as lighters, candles and...

  6. Uranium hydrogeochemical and stream sediment reconnaissance of the Candle NTMS quadrangle, Alaska

    International Nuclear Information System (INIS)

    Hardy, L.C.; D'Andrea, R.F. Jr.; Zinkl, R.J.

    1982-07-01

    This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Candle NTMS quadrangle, Alaska. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. These machine-readable data, as well as quarterly or semiannual program progress reports containing further information on the HSSR program in general, or on the Los Alamos National Laboratory (LANL) portion of the program in particular, are available from DOE's Technical Library at its Grand Junction Area Office. Presented in this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume; these data are, however, available on the magnetic tape. Appendices A through D describe the sample media and summarize the analytical results for each medium. The data have been subdivided by one of the Los Alamos National Laboratory sorting programs of Zinkl and others (1981a) into groups of stream-sediment, lake-sediment, stream-water, and lake-water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1,000,000 scale maps of pertinent elements have been included in this report. Also included are maps showing results of multivariate statistical analyses. Information on the field and analytical procedures used by the Los Alamos National Laboratory during sample collection and analysis may be found in any HSSR data release prepared by the Laboratory and will not be included in this report

  7. Flicker light-induced retinal vasodilation is unaffected by inhibition of epoxyeicosatrienoic acids and prostaglandins in humans.

    Science.gov (United States)

    Noonan, Jonathan E; Dusting, Gregory J; Nguyen, Thanh T; Jenkins, Alicia J; Man, Ryan E K; Best, William J; Dias, Daniel A; Jayasinghe, Nirupama S; Roessner, Ute; Lamoureux, Ecosse L

    2014-10-08

    To investigate the role of epoxyeicosatrienoic acids (EETs) and prostaglandins (PGs) in retinal blood vessel calibers and vasodilation during flicker light stimulation in humans. Twelve healthy nonsmokers participated in a balanced crossover study. Oral fluconazole 400 mg and dispersible aspirin 600 mg were used to inhibit production of EETs and PGs, respectively. Retinal imaging was performed 1 hour after drug ingestion with the Dynamic Vessel Analyzer. Resting calibers of selected vessel segments were recorded in measurement units (MU). Maximum percentage dilations during flicker stimulation were calculated from baseline calibers. We then studied six participants each after fluconazole and aspirin ingestions at 30-minute intervals for 2 hours. Within-subject differences were assessed by ANOVA and Dunnett-adjusted pairwise comparisons with significance taken at P flicker stimulation. Mean (SD) resting arteriole and venule calibers on no-drug visits were 119.6 (10.6) MU and 145.7 (17.0) MU, respectively. Fluconazole reduced mean (±95% CI) resting venule calibers by 5.1 (4.3) MU. In repeated measures participants, neither drug affected vasodilations, but fluconazole reduced resting venule calibers over 2 hours (P flicker light-induced retinal vasodilation in humans. However, EETs may play a role in the regulation of retinal vascular tone and blood flow under resting physiological conditions. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  8. In-Depth Functional Diagnostics of Mouse Models by Single-Flash and Flicker Electroretinograms without Adapting Background Illumination.

    Science.gov (United States)

    Tanimoto, Naoyuki; Michalakis, Stylianos; Weber, Bernhard H F; Wahl-Schott, Christian A; Hammes, Hans-Peter; Seeliger, Mathias W

    2016-01-01

    Electroretinograms (ERGs) are commonly recorded at the cornea for an assessment of the functional status of the retina in mouse models. Full-field ERGs can be elicited by single-flash as well as flicker light stimulation although in most laboratories flicker ERGs are recorded much less frequently than singleflash ERGs. Whereas conventional single-flash ERGs contain information about layers, i.e., outer and inner retina, flicker ERGs permit functional assessment of the vertical pathways of the retina, i.e., rod system, cone ON-pathway, and cone OFF-pathway, when the responses are evoked at a relatively high luminance (0.5 log cd s/m(2)) with varying frequency (from 0.5 to 30 Hz) without any adapting background illumination. Therefore, both types of ERGs complement an in-depth functional characterization of the mouse retina, allowing for a discrimination of an underlying functional pathology. Here, we introduce the systematic interpretation of the single-flash and flicker ERGs by demonstrating several different patterns of functional phenotype in genetic mouse models, in which photoreceptors and/or bipolar cells are primarily or secondarily affected.

  9. Sources of the flicker noise and technology of superconducting microstrips on the basis of yttrium-barium cuprate

    International Nuclear Information System (INIS)

    Karmanenko, S.F.; Semenov, A.A.; Leonov, V.N.; Bobyk', A.V.; Dedoborets, A.I.; Lunev, A.V.; Nashchekin, A.V.; Suris, R.A.

    2000-01-01

    Modeling of the YBa 2 Cu 3 O 7 epitaxial films annealing process showed that oxygen transitions near the low-angular block boundaries are the prevailing flicker noise sources in the superconducting microstrips. The technology of magnetron scattering and etching by chemical and ion-beam methods was applied by manufacture of the superconducting microstrips ∼ 1μm in size [ru

  10. Dependence of image flickering of negative dielectric anisotropy liquid crystal on the flexoelectric coefficient ratio and the interdigitated electrode structure

    International Nuclear Information System (INIS)

    Lee, Hyojin; Kim, Hyungmin; Kim, Jongyoon; Lee, Ji-Hoon

    2016-01-01

    We experimentally measured the splay (e s ) and the bend flexoelectric coefficients (e b ) of liquid crystal (LC) mixtures with negative dielectric anisotropy and investigated their effect on the image flicker of the LC mixtures driven with a low frequency electric field. Using the experimentally measured e s and e b , we simulated the transmittance (TR) response with the continuum model. First, we confirmed that the TR simulation results were approximated to the experimental data with only small variation. Second, we varied the simulation parameters of e s , e b , the separation (S), and the width (W) of the interdigitated electrodes and tried to find the optimum condition showing the least image flicker. Given W  =  3.0 μm and e b   =  5.7 pC m −1 , it was found that the image flicker could be minimized when the e s /e b value was about 2.4 and the S/W ratio was about 1.5. Because the e s /e b value of the rod-like LC material is generally less than 1, it is desirable to design an interdigitated electrode structure to minimize the image flicker effect. (paper)

  11. CALiPER Retail Lamps Study 3.1: Dimming, Flicker, and Power Quality Characteristics of LED A Lamps

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-12-31

    This CALiPER report examines the characteristics of a subset of lamps from CALiPER Retail Lamps Study 3 in more detail. Specifically, it focuses on the dimming, power quality, and flicker characteristics of 14 LED A lamps, as controlled by four different retail-available dimmers.

  12. CANDLE reactor: an option for simple, safe, high nuclear proliferation resistant , small waste and efficient fuel use reactor

    International Nuclear Information System (INIS)

    Sekimoto, H.

    2010-01-01

    The innovative nuclear energy systems have been investigated intensively for long period in COE-INES program and CRINES activities in Tokyo Institute of Technology. Five requirements; sustainability, safety, waste, nuclear-proliferation, and economy; are considered as inevitable requirements for nuclear energy. Characteristics of small LBE cooled CANDLE fast reactor developed in this Institute are discussed for these requirements. It satisfies clearly four requirements; safety, nonproliferation and safeguard, less wastes and sustainability. For the remaining requirement, economy, a high potential to satisfy this requirement is also shown

  13. Flicker-induced retinal vasodilatation is not dependent on complement factor H polymorphism in healthy young subjects.

    Science.gov (United States)

    Told, Reinhard; Palkovits, Stefan; Boltz, Agnes; Schmidl, Doreen; Napora, Katarzyna J; Werkmeister, René M; Haslacher, Helmuth; Frantal, Sophie; Popa-Cherecheanu, Alina; Schmetterer, Leopold; Garhöfer, Gerhard

    2014-11-01

    The complement factor H (CFH) tyrosine 402 histidine (Y402H, rs1061170) variant is known to be significantly associated with age-related macular degeneration (AMD). Whether this genetic variant may impact retinal blood flow regulation is largely unknown. This study investigated whether flicker-induced vasodilation, an indicator for the coupling between neural activity and blood flow, is altered in subjects carrying the rs1061170 risk allele. One hundred healthy subjects (aged between 18 and 45 years) were included in this study. Retinal blood flow regulation was tested by assessing retinal vessel calibres in response to stimulation with diffuse flicker light. Retinal vascular flicker responses were determined with a Dynamic Vessel Analyzer (DVA). In addition, genotyping for rs1061170 was performed. Eighteen subjects were homozygous for the risk allele C, 50 were homozygous for the ancestral allele T, and 31 subjects were heterozygous (CT). One subject had to be excluded from data evaluation, as no genetic analysis could be performed due to technical difficulties. Baseline diameters of retinal arteries (p = 0.39) and veins (p = 0.64) were comparable between the three groups. Flicker-induced vasodilation in both retinal arteries (p = 0.38) and retinal veins (p = 0.62) was also comparable between the three studied groups. Our data indicate that homozygous healthy young carriers of the C risk allele at rs1061170 do not show abnormal flicker-induced vasodilation in the retina. This suggests that the high-risk genetic variant of CFH polymorphism does not impact neuro-vascular coupling in healthy subjects. © 2014 The Authors. Acta Ophthalmologica published by John Wiley & Sons Ltd on behalf of Acta Ophthalmologica Scandinavica Foundation.

  14. Effect of Diffuse Luminance Flicker Light Stimulation on Total Retinal Blood Flow Assessed With Dual-Beam Bidirectional Doppler OCT.

    Science.gov (United States)

    Aschinger, Gerold C; Schmetterer, Leopold; Fondi, Klemens; Aranha Dos Santos, Valentin; Seidel, Gerald; Garhöfer, Gerhard; Werkmeister, René M

    2017-02-01

    We assess the increase in total retinal blood flow (TRBF) induced by flicker stimulation of the human retina in vivo and investigate the flicker induced hyperemia by means of a vascular flow model of the retinal circulation to study neurovascular coupling (NC). In six healthy subjects, TRBF was measured before and during stimulation with diffuse luminance flicker. Blood flow velocities in retinal vessels were measured via dual-beam bidirectional Doppler Fourier-domain optical coherence tomography (FD-OCT), retinal vessel diameters were assessed based on FD-OCT phase data. This allowed for the calculation of TRBF before and during visual stimulation. Additionally, a mathematical flow model for the retinal vasculature was adapted to study the implications of diameter variations on retinal perfusion. Measured and simulated perfusion was compared to draw conclusions on the diameter variations in different layers of the vascular tree. The measured mean baseline flow was 36.4 ± 6.5 μl/min while the mean flow during flicker stimulation was 53.4% ± 8.3 μl/min. The individual increase in TRBF during flicker stimulation ranged between 34% and 66%. The average increase in TRBF over all measured subjects was 47.6% ± 12.6%. Dual-beam bidirectional Doppler FD-OCT allowed quantifying NC in the human retina in vivo and may be a promising method for monitoring alterations in NC caused by various pathologies. The comparison of the measured data with the results obtained in the simulated vasculature indicates that the vasodilation induced by NC is more pronounced in smaller vessels.

  15. Retail Lamps Study 3.1: Dimming, Flicker, and Power Quality Characteristics of LED A Lamps

    Energy Technology Data Exchange (ETDEWEB)

    Royer, Michael P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poplawski, Michael E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brown, Charles C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    To date, all three reports in the retail lamps series have focused on basic performance parameters, such as lumen output, efficacy, and color quality. This report goes a step further, examining the photoelectric characteristics (i.e., dimming and flicker) of a subset of lamps from CALiPER Retails Lamps Study 3. Specifically, this report focuses on the dimming, power quality, and flicker characteristics of 14 LED A lamps, as controlled by four different retail-available dimmers. The results demonstrate notable variation across the various lamps, but little variation between the four dimmers. Overall, the LED lamps: ~tended to have higher relative light output compared to the incandescent and halogen benchmark at the same dimmer output signal (RMS voltage). The lamps’ dimming curves (i.e., the relationship between control signal and relative light output) ranged from linear to very similar to the square-law curve typical of an incandescent lamp. ~generally exhibited symmetrical behavior—the same dimming curve—when measured proceeding from maximum to minimum or minimum to maximum control signal. ~mostly dimmed below 10% of full light output, with some exceptions for specific lamp and dimmer combinations ~exhibited a range of flicker characteristics, with many comparing favorably to the level typical of a magnetically-ballasted fluorescent lamp through at least a majority of the dimming range. ~ always exceeded the relative (normalized) efficacy over the dimming range of the benchmark lamps, which rapidly decline in efficacy when they are dimmed. This report generally does not attempt to rank the performance of one product compared to another, but instead focuses on the collective performance of the group versus conventional incandescent or halogen lamps, the performance of which is likely to be the baseline for a majority of consumers. Undoubtedly, some LED lamps perform better—or more similar to conventional lamps—than others. Some perform desirably for one

  16. Flicker licker

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, T.

    1988-02-24

    Discusses the use of high frequency (h.f.) electronic ballasts to control fluorescent lighting. H.F. ballasts consume about 25% less power than conventional, switch-start control gear to produce the same light intensity. They eliminate stuttering starts and, according to a recent report, halve the number of headaches caused by lamps operating on a conventional 50Hz supply. H.F. ballasts are also smaller, lighter and have fewer parts than conventional ballasts, but they are more expensive. The high power factor in h.f. lighting gives two further advantages - one is lower demand on the building's ventilation system because the lamps produce less heat. Another benefit from low power consumption is an increase in a lamp's useful life. It is estimated that 2 years is a realistic payback on h.f. lighting in offices where lights are on about 12 hours per day. Sales in h.f. ballasts are now beginning to accelerate. There is a consensus between manufacturers to make their ballasts compatible with a range of fluorescent lamps. The exception is Phillips, who have chosen an argon lamp specially designed for use with its h.f. ballast. Their strategy is based on dimmer control - argon lamps are easier to dim smoothly than krypton lamps. Dimming allows adjustment of light levels to suit a given job and can also be used as part of an energy management system to dim or raise the lighting levels according to conditions.

  17. Traditional use of the Andean flicker (Colaptes rupicola as a galactagogue in the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Froemming Steve

    2006-05-01

    Full Text Available Abstract This paper explores the use of the dried meat and feathers of the Andean Flicker (Colaptes rupicola to increase the milk supply of nursing women and domestic animals in the Andes. The treatment is of preColumbian origin, but continues to be used in some areas, including the village in the southern Peruvian highlands where I do ethnographic research. I explore the factors giving rise to and sustaining the practice, relate it to other galactagogues used in the Andes and to the use of birds in ethnomedical and ethnoveterinary treatments in general, and situate it within the general tendency in the Andes and elsewhere to replicate human relations in the treatment of valuable livestock. The bird's use as a galactagogue appears to be motivated by both metaphorical associations and its perceived efficacy, and conceptually blends human and animal healthcare domains.

  18. Critical flicker frequency and continuous reaction times for the diagnosis of minimal hepatic encephalopathy

    DEFF Research Database (Denmark)

    Lauridsen, Mette Enok Munk; Jepsen, Peter; Vilstrup, Hendrik

    2011-01-01

    -to-perform reproducible bedside methods: the critical flicker frequency (CFF) and continuous reaction times (CRT) tests. A CFF reaction times) indicates cerebral dysfunction. 154 patients with acute or chronic liver disease with out overt hepatic...... encephalopathy (HE) underwent both tests at the same occasion. Both tests were abnormal in 20% of the patients and both tests were normal in 40% of the patients. In more than 1/3 the two tests were not in agreement as CFF classified 32% and CRT-index classified 48% of the patients as having MHE (p ....005). The two tests were weakly linearly correlated (r(2) = 0.14, p test correlated with the metabolic liver function measured by the Galactose Elimination Capacity (GEC), nor with the blood ammonia concentration. Both tests identified a large fraction of the patients as having MHE...

  19. Critical Flicker Fusion Predicts Executive Function in Younger and Older Adults.

    Science.gov (United States)

    Mewborn, Catherine; Renzi, Lisa M; Hammond, Billy R; Miller, L Stephen

    2015-11-01

    Critical flicker fusion (CFF), a measure of visual processing speed, has often been regarded as a basic metric underlying a number of higher cognitive functions. To test this, we measured CFF, global cognition, and several cognitive subdomains. Because age is a strong covariate for most of these variables, both younger (n = 72) and older (n = 57) subjects were measured. Consistent with expectations, age was inversely related to CFF and performance on all of the cognitive measures except for visual memory. In contrast, age-adjusted CFF thresholds were only positively related to executive function. Results showed that CFF predicted executive function across both age groups and accounted for unique variance in performance above and beyond age and global cognitive status. The current findings suggest that CFF may be a unique predictor of executive dysfunction. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation.

    Science.gov (United States)

    Li, Jian; Zhao, Zhihong; Li, Dianming; Tian, Haifeng; Zha, Fei; Feng, Hua; Guo, Lin

    2017-09-21

    Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.

  1. Quantitative retinal and choroidal blood flow during light, dark adaptation and flicker light stimulation in rats using fluorescent microspheres.

    Science.gov (United States)

    Shih, Yen-Yu I; Wang, Lin; De La Garza, Bryan H; Li, Guang; Cull, Grant; Kiel, Jeffery W; Duong, Timothy Q

    2013-02-01

    The present study aimed to quantify retinal and choroidal blood flow (BF) during light, dark adaptation and flicker light stimulation using the microsphere technique. Adult male Sprague-Dawley rats were anesthetized with isoflurane. Eyes were dark (Group I, n = 8), light (Group II, n = 8) adapted or stimulated with 10 Hz flicker light (Group III, n = 10). Retinal and choroidal BF were measured by a previously established method, using a mixture of 8 µm yellow-green and 10 µm red fluorescent microspheres. The microspheres were counted ex vivo in the dissected retina and choroid and in the reference arterial blood under a fluorescent microscope. The choroidal BF was 64.8 ± 29 µl/min (mean ± SD) during dark adaptation, not significantly different from that during light adaptation (66.0 ± 17.8 µl/min). The retinal BF was 13.5 ± 3.2 µl/min during 10 Hz flickering light stimulation, significantly higher than that during dark adaptation in the control fellow eyes (9.9 ± 2.9 µl/min). The choroidal BF values were not statistically different between flicker stimulation and dark adaptation. Retinal BF was 11.6 ± 2.9 µl/min during light adaptation. Dark adaptation did not increase retinal BF (Group I, 8.2 ± 2.4 µl/min; Group II, 9.9 ± 2.9 µl/min). These findings argue against a dark-induced or flicker-induced functional hyperemia in the choroid as a result of the demands of the outer retina. Retinal BF was not higher during dark adaptation. Our data support the conclusion that the inner retina has a higher energy demand in flicker conditions relative to dark.

  2. The JPL Hg(sup +) Extended Linear Ion Trap Frequency Standard: Status, Stability, and Accuracy Prospects

    Science.gov (United States)

    Tjoelker, R. L.; Prestage, J. D.; Maleki, L.

    1996-01-01

    Microwave frequency standards based on room temperature (sup 199)Hg(sup +) ions in a Linear Ion Trap (LITS) presently achieve a Signal to Noise and line Q inferred short frequency stability. Long term stability has been measured for averaging intervals up to 5 months with apparent sensitivity to variations in ion number/temperature limiting the flicker floor.

  3. A technique for flicker reduction in a volumetric three-dimensional display with a static image space

    Science.gov (United States)

    Koudsi, Badia; Refai, Hakki H.; Sluss, James J., Jr.

    2010-10-01

    An ongoing public-private research partnership has demonstrated a three-dimensional (3D) volumetric display system that incorporates a static image space. The 3D display system uses micro-electro-mechanical systems (MEMS) based mirror arrays to direct infrared light beams into an image space that exhibits two-step, twofrequency upconversion. A number of candidate image space materials have been evaluated, with 2%Er: NYF4 appearing to be most promising at this stage of the research. In this paper, the authors build upon prior work by investigating the response time of 2%Er:NYF4. In addition, a new technique for reducing flicker in the 3D images is described. The technique includes interlacing the 3D image slices in a way similar to the interlacing that occurs in the generation of television images. Adopting this technique has the potential to reduce the flicker that is presently evident, thereby improving the overall 3D image quality.

  4. Calculation of Booster power requirements and power line flicker for 1.5 GeV proton operation

    International Nuclear Information System (INIS)

    Meth, A.; Ratti, A.

    1992-01-01

    The Booster power requirements and power line flicker has been previously calculated for the 1 GEV proton cycle. Since then the maximum proton energy has been increased to 1.5 GEV, and the cycle period increased from 100 to 133 millisec. the design manual lists the peak magnet current as 2220A (previous value of 1672A). The maximum stored energy is increased by a factor of 1.763 and the power swing is increased by a factor of 1.32; increasing the flicker approximately by this factor. The required magnet voltage has been calculated and is given for the dipole and quadrupole strings. The total power at the AC bus bar isgiven. To calculate the reactive power, the dipole excitation is assumed to consist of 5--1000 volt supplies in series and sequentially switched. The quadrupole supply consist of 5--175 volt supplies in series and sequentially switched

  5. Dynamic brightness induction causes flicker adaptation, but only along the edges: Evidence against the neural filling-in of brightness

    Science.gov (United States)

    Robinson, Alan E.; de Sa, Virginia R.

    2013-01-01

    Is brightness represented in a point-for-point neural map that is filled in from the response of small, contrast-sensitive edge detector cells? We tested for the presence of this filled-in map by adapting to illusory flicker caused by a dynamic brightness-induction stimulus. Thereafter flicker sensitivity was reduced when our test region was the same size as the induced region, but not for smaller, inset regions. This suggests induced brightness is represented by either small edge-selective cells with no filling-in stage, or by contrast-sensitive spatial filters at many different scales, but not by a population of filled-in neurons arranged in a point-for-point map. PMID:23729768

  6. Wind turbines, flicker, and photosensitive epilepsy: characterizing the flashing that may precipitate seizures and optimizing guidelines to prevent them.

    Science.gov (United States)

    Harding, Graham; Harding, Pamela; Wilkins, Arnold

    2008-06-01

    Wind turbines are known to produce shadow flicker by interruption of sunlight by the turbine blades. Known parameters of the seizure provoking effect of flicker, i.e., contrast, frequency, mark-space ratio, retinal area stimulated and percentage of visual cortex involved were applied to wind turbine features. The proportion of patients affected by viewing wind turbines expressed as distance in multiples of the hub height of the turbine showed that seizure risk does not decrease significantly until the distance exceeds 100 times the hub height. Since risk does not diminish with viewing distance, flash frequency is therefore the critical factor and should be kept to a maximum of three per second, i.e., sixty revolutions per minute for a three-bladed turbine. On wind farms the shadows cast by one turbine on another should not be viewable by the public if the cumulative flash rate exceeds three per second. Turbine blades should not be reflective.

  7. Effects of Constant Flickering Light on Refractive Status, 5-HT and 5-HT2A Receptor in Guinea Pigs.

    Science.gov (United States)

    Li, Bing; Luo, Xiumei; Li, Tao; Zheng, Changyue; Ji, Shunmei; Ma, Yuanyuan; Zhang, Shuangshuang; Zhou, Xiaodong

    2016-01-01

    To investigate the effects of constant flickering light on refractive development, the role of serotonin (i.e.5-hydroxytryptamine, 5-HT)and 5-HT2A receptor in myopia induced by flickering light in guinea pigs. Forty-five guinea pigs were randomly divided into three groups: control, form deprivation myopia (FDM) and flickering light induced myopia (FLM) groups(n = 15 for each group). The right eyes of the FDM group were covered with semitransparent hemispherical plastic shells serving as eye diffusers. Guinea pigs in FLM group were raised with illumination of a duty cycle of 50% at a flash frequency of 0.5Hz. The refractive status, axial length (AL), corneal radius of curvature(CRC) were measured by streak retinoscope, A-scan ultrasonography and keratometer, respectively. Ultramicroscopy images were taken by electron microscopy. The concentrations of 5-HTin the retina, vitreous body and retinal pigment epithelium (RPE) were assessed by high performance liquid chromatography, the retinal 5-HT2A receptor expression was evaluated by immunohistofluorescence and western blot. The refraction of FDM and FLM eyes became myopic from some time point (the 4th week and the 6th week, respectively) in the course of the experiment, which was indicated by significantly decreased refraction and longer AL when compared with the controls (pguinea pigs. 5-HT and 5-HT2A receptor increased both in form deprivation myopia and flickering light induced myopia, indicating that 5-HT possibly involved in myopic development via binding to5-HT2A receptor.

  8. Correlation between Flicker-Induced Retinal Vessel Vasodilatation and Plasma Biomarkers of Endothelial Dysfunction in Hypertensive Patients.

    Science.gov (United States)

    Machalińska, Anna; Pius-Sadowska, Ewa; Babiak, Katarzyna; Sałacka, Anna; Safranow, Krzysztof; Kawa, Miłosz Piotr; Machaliński, Bogusław

    2018-01-01

    Hypertension (HT) strongly affects the vascular endothelium, resulting in chronic inflammatory disease. Dynamic vessel analysis (DVA) is a modern methodological approach to analyze vascular function in the retinal microcirculation. The aim of this study was to examine whether a defective retinal vessels response is associated with HT-induced endothelial dysfunction. Retinal vessel reactions to flicker stimulation were examined by DVA in both eyes of 37 hypertensive and 41 healthy control subjects. Plasma concentrations of C-reactive protein (CRP), interleukin-6, and tumor necrosis factor alpha (TNFɑ) were measured using the enzyme-linked immunosorbent assay. Both arterial and vein responses to flicker stimulation were significantly decreased in patients with HT compared with the healthy controls (dilatation of the arteries was lower in the HT group by, on average, 1.31, p = 0.001 and dilatation of the veins was lower in the HT group by, on average, 1.32, p = 0.002) after independent adjustment for age, sex, body mass index, and pressure values. In the hypertensive group, there was a negative correlation between the arterial response to flicker stimulation and the plasma CRP concentration (Spearman's Rank-order Coefficient (Rs) = -0.29, p = 0.07). Similarly, the plasma TNFα concentrations negatively correlated with the arterial response to flicker stimulation (Rs = -0.39, p = 0.02). Our results indicate that DVA directly reflects the actual metabolic status of the retinal endothelium. DVA might be used as an early noninvasive screening tool to detect vascular dysregulation and pan-endothelial dysfunction in patients with HT.

  9. Investigation of human visual cortex responses to flickering light using functional near infrared spectroscopy and constrained ICA

    Directory of Open Access Journals (Sweden)

    Nguyen Duc Thang

    2014-11-01

    Full Text Available The human visual sensitivity to the flickering light has been under investigation for decades. The finding of research in this area can contribute to the understanding of human visual system mechanism and visual disorders, and establishing diagnosis and treatment of diseases. The aim of this study is to investigate the effects of the flickering light to the visual cortex by monitoring the hemodynamic responses of the brain with the functional near infrared spectroscopy (fNIRS method. Since the acquired fNIRS signals are affected by physiological factors and measurement artifacts, constrained independent component analysis (cICA was applied to extract the actual fNIRS responses from the obtained data. The experimental results revealed significant changes (p < 0.0001 of the hemodynamic responses of the visual cortex from the baseline when the flickering stimulation was activated. With the uses of cICA, the contrast to noise ratio (CNR, reflecting the contrast of hemodynamic concentration between rest and task, became larger. This indicated the improvement of the fNIRS signals when the noise was eliminated. In subsequent studies, statistical analysis was used to infer the correlation between the fNIRS signals and the visual stimulus. We found that there was a slight decrease of the oxygenated hemoglobin concentration (about 5.69% over four frequencies when the modulation increased. However, the variations of oxy and deoxy-hemoglobin were not statistically significant.

  10. Diurnal changes of critical flicker frequency in patients with liver cirrhosis and their relationship with sleep disturbances.

    Science.gov (United States)

    Gencdal, Genco; Gunsar, Fulya; Meral, Cenk Emre; Salman, Esin; Gürsel, Berna; Oruç, Nevin; Karasu, Zeki; Ersoz, Galip; Akarca, Ulus S

    2014-12-01

    We aimed to measure the diurnal changes of critical flicker frequency in healthy subjects and cirrhotic patients and to investigate their relationship with sleep disturbance. Cirrhotic patients and healthy volunteers were included. All groups completed the Pittsburgh Sleep Quality Index and a simple sleep questionnaire. Sleep disturbance was defined as a Pittsburgh Sleep Quality Index score of >5. Critical flicker frequency was measured twice a day to detect diurnal abnormalities. Overall, 59 cirrhotic patients (54.2% males, Mean Age 59 ± 11 years) and 18 controls (39.9% males, Mean Age 58 ± 9 years) were included. Sleep disturbances were more common in cirrhotics (66.1%) than controls (38.9%, pflicker frequency was not related to decompensation. The nocturnal values were higher than the morning values in cirrhotics (64.4%), but not in controls (pflicker frequency were observed in cirrhotics but not in controls. Sleep disturbances in cirrhotics appear to be associated with deviations of the diurnal rhythm of critical flicker frequency rather than with clinical parameters such as the clinical stages of cirrhosis and the Model For End-Stage Liver Disease and Child-Pugh scores. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  11. Radiology reading-caused fatigue and measurement of eye strain with critical flicker fusion frequency

    International Nuclear Information System (INIS)

    Maeda, Eriko; Yoshikawa, Takeharu; Hayashi, Naoto; Akai, Hiroyuki; Hanaoka, Shouhei; Sasaki, Hiroki; Matsuda, Izuru; Yoshioka, Naoki; Ohtomo, Kuni

    2011-01-01

    The aim of this study was to investigate eye fatigue that could impair diagnostic accuracy by measuring the critical flicker fusion frequency (CFFF) before and after reading. CFFF was measured before and after about 4 h of health checkup reading in seven healthy volunteer radiologists. A questionnaire was also completed on duration of sleep the night before the experiment, average duration of sleep, and subjective fatigue using a visual analog scale (corrected to a 0-1 scale, 0 indicating the worst fatigue ever experienced). After-reading subjective fatigue was significantly greater (before 0.52±0.15, after 0.42±0.15), and CFFF was significantly lower (before 40.9±2.4, after 39.9±2.0). There was no significant correlation between subjective fatigue and CFFF, either before or after or between before- and after-reading differences in subjective fatigue and CFFF. Shorter duration of sleep the night before significantly correlated with lower CFFF (Pearson's correlation coefficient): before 0.42, P=0.0047; after 0.52, P=0.0003. CFFF declines after reading and can be considered useful as an indicator of fatigue induced by radiology reading. CFFF declines significantly when sleep is reduced the day before reading without correlation with subjective fatigue, meaning that sleep deprivation can cause an unaware decline in visual function. (author)

  12. Meteoroid rotation and fireball flickering: a case study of the Innisfree fireball

    Science.gov (United States)

    Beech, Martin

    2001-09-01

    Some 5 per cent of bright meteors show rapid, quasi-periodic brightness variations. It is argued that this effect, observationally known as flickering, is a manifestation of the rotational modulation of surface mass loss through ablation of a non-spherical meteoroid. We develop a set of time-dependent, single-body ablation equations that include the effect of cross-section area modulation. We present a discussion of the effects that the rotation of a non-spherical meteoroid has on the resultant meteor light curve, and we look in depth at the data related to the fireball associated with the fall of the Innisfree meteorite. We find that the parent object to the Innisfree meteorite was spinning at a rotation frequency of 2.5Hz when it encountered the Earth's upper atmosphere. We also find that the Innisfree parent body had an initial mass of about 20kg and that the ratio of its semiminor and semimajor axes was about 0.5.

  13. Emotion has no impact on attention in a change detection flicker task

    Directory of Open Access Journals (Sweden)

    Robert Colin Alan Bendall

    2015-10-01

    Full Text Available Past research provides conflicting findings regarding the influence of emotion on visual attention. Early studies suggested a broadening of attentional resources in relation to positive mood. However, more recent evidence indicates that positive emotions may not have a beneficial impact on attention, and that the relationship between emotion and attention may be mitigated by factors such as task demand or stimulus valence. The current study explored the effect of emotion on attention using the change detection flicker paradigm. Participants were induced into positive, neutral, and negative mood states and then completed a change detection task. A series of neutral scenes were presented and participants had to identify the location of a disappearing item in each scene. The change was made to the centre or the periphery of each scene and it was predicted that peripheral changes would be detected quicker in the positive mood condition and slower in the negative mood condition, compared to the neutral condition. In contrast to previous findings emotion had no influence on attention and whilst central changes were detected faster than peripheral changes, change blindness was not affected by mood. The findings suggest that the relationship between emotion and visual attention is influenced by the characteristics of a task, and any beneficial impact of positive emotion may be related to processing style rather than a broadening of attentional resources.

  14. Electrical conduction mechanism in conjugated polymers studied using Flicker noise spectroscopy

    International Nuclear Information System (INIS)

    Parkhutik, Vitali; Patil, Rahul; Harima, Yutaka; Matveyeva, Eugenia

    2006-01-01

    We have performed detailed analysis of the fluctuations of the electrical current in electrochemically deposited conductive polymers (CP) using as example polyaniline and poly(3-methylthiophene). These heterogeneous and disordered materials cannot be analyzed in terms of classical conduction mechanisms (like Schottky or Poole-Frenkel emission). Instead, the electrical transport in CPs is to be considered as a stochastic process with large component of noise. We have been able to distinguish several modes of the conduction process in CPs by applying Flicker noise spectroscopy. Thus, we have established that the transport of charge carriers in highly doped CPs is much less correlated than in non-doped ones at the same electric field strength. While applied electric field increases, correlations become lower in a sequence of elementary events contributing to the conductivity of CP. Apparently, the change in the correlation length corresponds to changing mechanism of the electrical conduction. The lower correlation in highly doped sample can be attributed to various factors including change in CP conformation, enhancement in interchain charge transfer and generation of polaron lattice

  15. Two Visual Training Paradigms Associated with Enhanced Critical Flicker Fusion Threshold.

    Science.gov (United States)

    Zhou, Tianyou; Náñez, Jose E; Zimmerman, Daniel; Holloway, Steven R; Seitz, Aaron

    2016-01-01

    Critical flicker fusion thresholds (CFFTs) describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision-training approaches, one involving contrast sensitivity training and the other directional dot-motion training, compared to an active control group trained on Sudoku. The three training paradigms were compared on their effectiveness for altering CFFT. Directional dot-motion and contrast sensitivity training resulted in significant improvement in CFFT, while the Sudoku group did not yield significant improvement. This finding indicates that dot-motion and contrast sensitivity training similarly transfer to effect changes in CFFT. The results, combined with prior research linking CFFT to high-order cognitive processes such as reading ability, and studies showing positive impact of both dot-motion and contrast sensitivity training in reading, provide a possible mechanistic link of how these different training approaches impact reading abilities.

  16. Machinability of drilling T700/LT-03A carbon fiber reinforced plastic (CFRP) composite laminates using candle stick drill and multi-facet drill

    Science.gov (United States)

    Wang, Cheng-Dong; Qiu, Kun-Xian; Chen, Ming; Cai, Xiao-Jiang

    2015-03-01

    Carbon Fiber Reinforced Plastic (CFRP) composite laminates are widely used in aerospace and aircraft structural components due to their superior properties. However, they are regarded as difficult-to-cut materials because of bad surface quality and low productivity. Drilling is the most common hole making process for CFRP composite laminates and drilling induced delamination damage usually occurs severely at the exit side of drilling holes, which strongly deteriorate holes quality. In this work, the candle stick drill and multi-facet drill are employed to evaluate the machinability of drilling T700/LT-03A CFRP composite laminates in terms of thrust force, delamination, holes diameter and holes surface roughness. S/N ratio is used to characterize the thrust force while an ellipse-shaped delamination model is established to quantitatively analyze the delamination. The best combination of drilling parameters are determined by full consideration of S/N ratios of thrust force and the delamination. The results indicate that candle stick drill will induce the unexpected ellipse-shaped delamination even at its best drilling parameters of spindle speed of 10,000 rpm and feed rate of 0.004 mm/tooth. However, the multi-facet drill cutting at the relative lower feed rate of 0.004 mm/tooth and lower spindle speed of 6000 rpm can effectively prevent the delamination. Comprehensively, holes quality obtained by multi-facet drill is much more superior to those obtained by candle stick drill.

  17. Modelos de horno de arco eléctrico para estudios del efecto flicker

    Directory of Open Access Journals (Sweden)

    Catalina González Castaño

    2016-06-01

    Full Text Available Objetivo: El objetivo de este artículo es evaluar las fluctuaciones de voltaje o flicker de dos modelos de un horno de arco eléctrico a través de la comparación con datos reales. Método: El primer modelo se fundamenta a partir del principio de conservación de la energía, de la cual se obtiene una ecuación diferencial no lineal que captura la característica voltaje – corriente del arco eléctrico. Las fluctuaciones de voltaje se generan con un circuito de caos que modula la amplitud del voltaje del arco eléctrico. El segundo modelo está basado en las relaciones empíricas entre la longitud de arco, la tensión y la corriente a través del arco. Las fluctuaciones de voltaje se obtienen agregando una señal aleatoria a la longitud del arco eléctrico. Ambos modelos son implementados en PSCADTM. Resultados: Los resultados de ambos modelos son comparados con mediciones reales tomadas en la etapa más crítica de la operación del horno, y muestran que el modelo basado en la conservación de la potencia presenta un menor error medio cuadrático promedio en los voltajes y corrientes de 5,6 V y 1.7 kA frente a 27,2 V y 3.38 kA obtenidos con el segundo modelo. Conclusiones: Ambos modelos consideran la no linealidad y comportamiento aleatorio que exhibe este tipo de carga, validando su inclusión en modelos computacionales de sistemas eléctricos de potencia.

  18. Effect of oxygen on neuronal excitability measured by critical flicker fusion frequency is dose dependent.

    Science.gov (United States)

    Kot, Jacek; Winklewski, Pawel J; Sicko, Zdzislaw; Tkachenko, Yurii

    2015-01-01

    Reactive oxygen species are involved in the functional changes necessary for synaptic plasticity, memory, and cognitive function. It is far from clear whether the increased excitability, and which forms of neuronal excitability, should be considered a part of the learning process or, rather, cellular manifestation of neuronal oxygen poisoning. It is yet to be elucidated whether oxygen (O2)-induced learning and poisoning use the same or distinct cellular pathways. We hypothesized that O2-induced neuronal excitability might use the same or an intertwined signaling cascade as the poisoning cellular pathway. Eighty-one healthy, young males, mean age 27.7 ± 4.1 (SD) years, were exposed in the hyperbaric chamber to 0.7 atmosphere absolute (ATA) O2, 1.4 ATA O2, and 2.8 ATA O2. The critical flicker fusion frequency (CFFF), oxyhemoglobin saturation (SiO2), and heart rate (HR) were measured before exposure, after 30 min of oxygen breathing while still at pressure and then after exposure. Normobaric (0.7 ATA) O2 exposure did not affect CFFF and HR. Medium hyperbaric O2 exposure (1.4 ATA) decreased CFFF but HR remained unchanged. High hyperbaric O2 exposure (2.8 ATA) increased CFFF and diminished HR. SiO2 was similar in all investigated groups. A correlation between CFFF, HR, and SiO2 was observed only at low oxygen (0.7 ATA). The effect of O2 on neuronal excitability measured by CFFF in young healthy men was dose dependent: 0.7 ATA O2 did not affect CFFF; CFFF were significantly jeopardized at 1.4 ATA O2, while CFFF recovered at 2.8 ATA. With 2.8 ATA O2, the CFFF and oxygen poisoning transduction pathways seemed to be intertwined.

  19. A contingency-based approach to the etiology of 'disorganized' attachment: the 'flickering switch' hypothesis.

    Science.gov (United States)

    Koós, O; Gergely, G

    2001-01-01

    The authors present a new approach to the etiology of disorganized attachment based on contingency detection theory. According to this view, the relevant common factor in parental maltreatment and unresolved loss that leads to disorganized attachment has to do with the type of "deviant contingency environment" that both of these conditions generate. In such environments, infants experience periods of being in control followed by periods of sudden loss of control over the caregiver's behavior. The authors hypothesize that this adversely affects the developmental unfolding of the infant's innate "contingency detection module" (Gergely & Watson, 1999), which normally involves a maturational shift around 3 months from an initial attention bias for perfectly contingent stimulation to an emerging preference for less-than-perfect social contingencies. The periodically changing controllability of abusive and dissociating "unresolved" attachment figures is hypothesized to block this process and to lead to the defensive fixation of a dysfunctional "flickering contingency switch" mechanism with two dominant and competing target positions (self-oriented vs. other-oriented). This results in the dissociative style of attention and behavioral organization characteristic of disorganized infant attachment. The authors summarize the preliminary results of an empirical study that provides support for this model in 6.5-month-old infants using a modified Still-Face situation (the Mirror Interaction Situation). The study demonstrates differential emotional and behavioral reactions to sudden loss of maternal contingency and a specific interest in exploring the perfectly contingent self-image in the mirror in infants who at 12 months become categorized as "disorganized" in the Strange Situation.

  20. Flickering AGN can explain the strong circumgalactic O VI observed by COS-Halos

    Science.gov (United States)

    Oppenheimer, Benjamin D.; Segers, Marijke; Schaye, Joop; Richings, Alexander J.; Crain, Robert A.

    2018-03-01

    Proximity zone fossils (PZFs) are ionization signatures around recently active galactic nuclei (AGNs) where metal species in the circumgalactic medium remain overionized after the AGNs have shut off due to their long recombination time scales. We explore cosmological zoom hydrodynamic simulations, using the EAGLE (Evolution and Assembly of GaLaxies and their Environments) model paired with a non-equilibrium ionization and cooling module including time-variable AGN radiation to model PZFs around star-forming disc galaxies in the z ˜ 0.2 Universe. Previous simulations typically underestimated the O VI content of galactic haloes, but we show that plausible PZF models increase O VI column densities by 2 - 3 × to achieve the levels observed around COS-Halos star-forming galaxies out to 150 kpc. Models with AGN bolometric luminosities ≳ 1043.6erg s- 1, duty cycle fractions ≲ 10 per cent, and AGN lifetimes ≲ 106 yr are the most promising, because their supermassive black holes grow at the cosmologically expected rate and they mostly appear as inactive AGN, consistent with COS-Halos. The central requirement is that the typical star-forming galaxy hosted an active AGN within a time-scale comparable to the recombination time of a high metal ion, which for circumgalactic O VI is ≈107 yr. H I, by contrast, returns to equilibrium much more rapidly due to its low neutral fraction and does not show a significant PZF effect. O VI absorption features originating from PZFs appear narrow, indicating photoionization, and are often well aligned with lower metal ion species. PZFs are highly likely to affect the physical interpretation of circumgalactic high ionization metal lines if, as expected, normal galaxies host flickering AGN.

  1. Method of flicker-noise spectroscopy of cosmic ray muon flux variations caused by non-stationary processes

    International Nuclear Information System (INIS)

    Borog, V V; Dmitrieva, A N; Kovylyaeva, A A

    2017-01-01

    A new method of identifying signals in a statistically noisy non-stationary time series is presented. Unlike in the Fourier and wavelet analyses, in the processing of data no assumptions about the structure of analyzed signal is made. The proposed method of flicker-noise spectroscopy is illustrated with a real time series related to monitoring of solar and cosmic radiation during GLE#72 event using ground-level muon hodoscope. The method is applicable for the analysis of a wide range of various helio- and geophysical processes. (paper)

  2. Effect of the Green/Blue Flicker Matrix for P300-Based Brain-Computer Interface: An EEG-fMRI Study.

    Science.gov (United States)

    Ikegami, Shiro; Takano, Kouji; Wada, Makoto; Saeki, Naokatsu; Kansaku, Kenji

    2012-01-01

    The visual P300-brain-computer interface, a popular system for EEG-based BCI, utilizes the P300 event-related potential to select an icon arranged in a flicker matrix. In the conventional P300-BCI speller paradigm, white/gray luminance intensification of each row/column in the matrix is used. In an earlier study, we applied green/blue luminance and chromatic change in the P300-BCI system and reported that this luminance and chromatic flicker matrix was associated with better performance and greater subject comfort compared with the conventional white/gray luminance flicker matrix. In this study, we used simultaneous EEG-functional magnetic resonance imaging (fMRI) recordings to identify brain areas that were more enhanced in the green/blue flicker matrix than in the white/gray flicker matrix, as these may highlight areas devoted to improved P300-BCI performance. The peak of the positive wave in the EEG data was detected under both conditions, and the peak amplitudes were larger at the parietal and occipital electrodes, particularly in the late components, under the green/blue condition than under the white/gray condition. fMRI data showed activation in the bilateral parietal and occipital cortices, and these areas, particularly those in the right hemisphere, were more activated under the green/blue condition than under the white/gray condition. The parietal and occipital regions more involved in the green/blue condition were part of the areas devoted to conventional P300s. These results suggest that the green/blue flicker matrix was useful for enhancing the so-called P300 responses.

  3. Masking of random-walk motion by flicker, and its role in the allocation of motion in the on-line jitter illusion.

    Science.gov (United States)

    Park, Adela S Y; Bedggood, Phillip A; Metha, Andrew B; Anderson, Andrew J

    2017-08-01

    Typically, perceptual stabilization mechanisms make us unaware of the retinal image motion produced by the small, involuntary eye movements our eyes constantly make during fixation. The breakdown of perceptual stability is demonstrated by the on-line jitter illusion, in which a circular static pattern appears to jitter coherently when surrounded by a flickering annular pattern. Although both regions of the stimulus are subject to retinal motion from eye movements, the visual system attributes this motion to the central static region in the form of visual jitter, while the surrounding flickering region remains perceptually stable. We investigated factors influencing this allocation of motion and reference frame in the on-line jitter illusion. The flickering of the surround was found to impair the detection of simultaneous random-walk motion in this area, giving a detection reliability of around 80% for motion approximating that from fixational eye movements. Changes to spatial texture and location of flicker (centre vs. surrounding annulus) had little effect on the final percept. However, use of a nonconcentric stimulus resulted in a marked reduction in apparent jitter in all subjects. Our results suggest for the on-line jitter illusion, allocation of motion and reference frame is influenced by the general principle that, if one region surrounds another, the surrounding region tends to be allocated as the frame of reference. When this factor is controlled for, spatial textures, location of flicker, and the masking of motion by flicker have a smaller but measurable influence on the final percept. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Identification of predominant odorants in thai desserts flavored by smoking with "Tian Op", a traditional Thai scented candle.

    Science.gov (United States)

    Watcharananun, Wanwarang; Cadwallader, Keith R; Huangrak, Kittiphong; Kim, Hun; Lorjaroenphon, Yaowapa

    2009-02-11

    "Tian Op", a traditional Thai scented candle, is used for the smoking and flavoring of sweets, cakes, and other desserts for the purpose of adding a unique aroma to the final product. Gas chromatography-olfactometry, aroma extract dilution analysis, and GC-MS were applied to identify the potent odorants in two types of traditional Thai desserts ("num dok mai" and "gleep lum duan") prepared using a Tian Op smoking process. On the basis of the results of AEDA and calculated odor-activity values, the predominant odorants in the Tian Op flavored desserts were vinyl ketones (C(5)-C(9)), n-aldehydes (C(5)-C(11)), (E)-2-unsaturated aldehydes (C(8)-C(11)), and omega-1-unsaturated aldehydes (C(8) and C(9)). Sensory studies of model mixtures confirmed the importance of n-aldehydes, omega-1-unsaturated aldehydes, and guaiacol as predominant odorants; however, the results showed that vinyl ketones and (E)-2-unsaturated aldehydes, despite having high odor-activity values, may be of only minor importance in the typical aroma profiles of traditional Tian Op smoked desserts.

  5. Facile Fabrication and Characterization of a PDMS-Derived Candle Soot Coated Stable Biocompatible Superhydrophobic and Superhemophobic Surface.

    Science.gov (United States)

    Iqbal, R; Majhy, B; Sen, A K

    2017-09-13

    We report a simple, inexpensive, rapid, and one-step method for the fabrication of a stable and biocompatible superhydrophobic and superhemophobic surface. The proposed surface comprises candle soot particles embedded in a mixture of PDMS+n-hexane serving as the base material. The mechanism responsible for the superhydrophobic behavior of the surface is explained, and the surface is characterized based on its morphology and elemental composition, wetting properties, mechanical and chemical stability, and biocompatibility. The effect of %n-hexane in PDMS, the thickness of the PDMS+n-hexane layer (in terms of spin coating speed) and sooting time on the wetting property of the surface is studied. The proposed surface exhibits nanoscale surface asperities (average roughness of 187 nm), chemical compositions of soot particles, very high water and blood repellency along with excellent mechanical and chemical stability and excellent biocompatibility against blood sample and biological cells. The water contact angle and roll-off angle is measured as 160° ± 1° and 2°, respectively, and the blood contact angle is found to be 154° ± 1°, which indicates that the surface is superhydrophobic and superhemophobic. The proposed superhydrophobic and superhemophobic surface offers significantly improved (>40%) cell viability as compared to glass and PDMS surfaces.

  6. Estimating annoyance to calculated wind turbine shadow flicker is improved when variables associated with wind turbine noise exposure are considered.

    Science.gov (United States)

    Voicescu, Sonia A; Michaud, David S; Feder, Katya; Marro, Leonora; Than, John; Guay, Mireille; Denning, Allison; Bower, Tara; van den Berg, Frits; Broner, Norm; Lavigne, Eric

    2016-03-01

    The Community Noise and Health Study conducted by Health Canada included randomly selected participants aged 18-79 yrs (606 males, 632 females, response rate 78.9%), living between 0.25 and 11.22 km from operational wind turbines. Annoyance to wind turbine noise (WTN) and other features, including shadow flicker (SF) was assessed. The current analysis reports on the degree to which estimating high annoyance to wind turbine shadow flicker (HAWTSF) was improved when variables known to be related to WTN exposure were also considered. As SF exposure increased [calculated as maximum minutes per day (SFm)], HAWTSF increased from 3.8% at 0 ≤ SFm wind turbine-related features, concern for physical safety, and noise sensitivity. Reported dizziness was also retained in the final model at p = 0.0581. Study findings add to the growing science base in this area and may be helpful in identifying factors associated with community reactions to SF exposure from wind turbines.

  7. CALiPER Report 20.2: Dimming, Flicker, and Power Quality Characteristics of LED PAR38 Lamps

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2014-03-31

    This report focuses on the flicker and power quality performance of the Series 20 lamps at full output and various dimmed levels. All of the Series 20 PAR38 lamps that manufacturers claimed to be dimmable (including all halogen lamps) were evaluated individually (one lamp at a time) both on a switch and under the control of a phase-cut dimmer designed for use with "all classes of bulbs." Measurements of luminous flux, flicker, and power quality were taken at 10 target dimmed settings and compared with operation on a switch. Because only a single unit of each product was evaluated on a single dimmer that may or may not have been recommended by its manufacturer, this report focuses on the performance of the products relative to each other, rather than the best-case performance of each lamp or variation in performance delivered from each lamp. Despite these limitations, the results suggest that LED performance is improving, and performance trends are beginning to emerge, perhaps due in part to the identification of preferred LED driver strategies for lamp products.

  8. Flicker noise comparison of direct conversion mixers using Schottky and HBT dioderings in SiGe:C BiCMOS technology

    DEFF Research Database (Denmark)

    Michaelsen, Rasmus Schandorph; Johansen, Tom Keinicke; Tamborg, Kjeld

    2015-01-01

    In this paper, we present flicker noise measurements of two X-band direct conversion mixers implemented in a SiGe:C BiCMOS technology. Both mixers use a ring structure with either Schottky diodes or diode-connected HBTs for double balanced operation. The mixers are packaged in a metal casing...

  9. The Effect of Acutely Elevated Intraocular Pressure on the Functional and Blood Flow Responses of the Rat Retina to Flicker Stimulation.

    Science.gov (United States)

    Tan, Bingyao; MacLellan, Benjamin; Mason, Erik; Bizheva, Kostadinka K

    2017-10-01

    To evaluate the effect of acutely elevated intraocular pressure (IOP) on the functional and blood flow responses of the rat retina to flicker stimulation. Brown Norway (n = 15) rats were dark-adapted before ketamine/xylazine anesthesia. IOP was raised acutely in one eye to ∼45 mm Hg with a vascular loop. In 11 rats, white light flicker stimulus (10 Hz, 2 seconds duration, 0.80 log scotopic cd·s/m2) was applied before and during IOP elevation, and 10 minutes after loop removal. Changes in the total retinal blood flow (TRBF) and retinal function induced by the visual stimulus were measured simultaneously with a combined optical coherence tomography (OCT) + electroretinography (ERG) system. Systemic blood pressure was measured in the remaining four rats frequently from 10 to 90 minutes post anesthesia injection. The systemic blood pressure remained at 99 ± 4 mm Hg throughout the measurements (n = 4). Under normal IOP, the TRBF was 5.6 ± 1.9 μL/min, and the average retinal blood vessel size (BVS) in the vicinity of the optic nerve head (ONH) was 44.1 ± 4.5 μm. During IOP elevation, the TRBF was significantly lower (3.8 ± 1.2 μL/min, P flicker-induced TRBF change measured under normal IOP (6.0 ± 3.3%) was reduced significantly to 0.1 ± 0.3% (P flicker stimulation.

  10. The reliability and internal consistency of one-shot and flicker change detection for measuring individual differences in visual working memory capacity.

    Science.gov (United States)

    Pailian, Hrag; Halberda, Justin

    2015-04-01

    We investigated the psychometric properties of the one-shot change detection task for estimating visual working memory (VWM) storage capacity-and also introduced and tested an alternative flicker change detection task for estimating these limits. In three experiments, we found that the one-shot whole-display task returns estimates of VWM storage capacity (K) that are unreliable across set sizes-suggesting that the whole-display task is measuring different things at different set sizes. In two additional experiments, we found that the one-shot single-probe variant shows improvements in the reliability and consistency of K estimates. In another additional experiment, we found that a one-shot whole-display-with-click task (requiring target localization) also showed improvements in reliability and consistency. The latter results suggest that the one-shot task can return reliable and consistent estimates of VWM storage capacity (K), and they highlight the possibility that the requirement to localize the changed target is what engenders this enhancement. Through a final series of four experiments, we introduced and tested an alternative flicker change detection method that also requires the observer to localize the changing target and that generates, from response times, an estimate of VWM storage capacity (K). We found that estimates of K from the flicker task correlated with estimates from the traditional one-shot task and also had high reliability and consistency. We highlight the flicker method's ability to estimate executive functions as well as VWM storage capacity, and discuss the potential for measuring multiple abilities with the one-shot and flicker tasks.

  11. Low visual cortex GABA levels in hepatic encephalopathy: links to blood ammonia, critical flicker frequency, and brain osmolytes.

    Science.gov (United States)

    Oeltzschner, Georg; Butz, Markus; Baumgarten, Thomas J; Hoogenboom, Nienke; Wittsack, Hans-Jörg; Schnitzler, Alfons

    2015-12-01

    The pathogenesis of hepatic encephalopathy (HE) is not fully understood yet. Hyperammonemia due to liver failure and subsequent disturbance of cerebral osmolytic balance is thought to play a pivotal role in the emergence of HE. The aim of this in-vivo MR spectroscopy study was to investigate the levels of γ-aminobutyric acid (GABA) and its correlations with clinical symptoms of HE, blood ammonia, critical flicker frequency, and osmolytic levels. Thirty patients with minimal HE or HE1 and 16 age-matched healthy controls underwent graduation of HE according to the West-Haven criteria and including the critical flicker frequency (CFF), neuropsychometric testing and blood testing. Edited proton magnetic resonance spectroscopy ((1)H MRS) was used to non-invasively measure the concentrations of GABA, glutamate (Glu), glutamine (Gln), and myo-inositol (mI) - all normalized to creatine (Cr) - in visual and sensorimotor cortex. GABA/Cr in the visual area was significantly decreased in mHE and HE1 patients and correlated both to the CFF (r = 0.401, P = 0.013) and blood ammonia levels (r = -0.434, P = 0.006). Visual GABA/Cr was also strongly linked to mI/Cr (r = 0.720, P < 0.001) and Gln/Cr (r = -0.699, P < 0.001). No group differences or correlations were found for GABA/Cr in the sensorimotor area. Hepatic encephalopathy is associated with a regional specific decrease of GABA levels in the visual cortex, while no changes were revealed for the sensorimotor cortex. Correlations of visual GABA/Cr with CFF, blood ammonia, and osmolytic regulators mI and Gln indicate that decreased visual GABA levels might contribute to HE symptoms, most likely as a consequence of hyperammonemia.

  12. Agreement of New Automated Matched Alternation Flicker using Undilated Fundus Photography for the Detection of Glaucomatous Structural Change.

    Science.gov (United States)

    Yun, Il Suk; Rho, Seungsoo; Jang, Seran; Ahn, Jaehong; Choi, Jung-Ju; Lee, Marvin

    2017-03-01

    To determine the agreement among glaucoma experts and general ophthalmologists regarding detection of glaucomatous structural changes using a new automated matched alternation flicker (AMAF) method with fundus photographs (FPs) of undilated eyes. Sixty-six pairs of FPs of normal tension glaucoma patients were collected. FPs were taken at intervals of more than 12 months. Alternating flicker images were created using a new AMAF application. In a blinded manner, two glaucoma experts and two general ophthalmologists compared the presence of glaucomatous structural changes using either the AMAF method or the side-by-side comparison method. The interobserver and intraobserver agreements were compared using the Bland and Altman plot analysis. The glaucoma experts detected more glaucoma progression using the AMAF method (average, 50.7%) compared with the side-by-side method (average, 32.5%). General ophthalmologists detected more glaucomatous progression with the AMAF method (average, 40.9%) than with the side-by-side method (average, 25.0%). The AMAF method showed fair to substantial interreader agreement (k = 0.511-0.724) and fair to perfect intrareader agreement (k = 0.631-0.943). Interreader and intrareader agreements using the AMAF method were better for the glaucoma experts compared with the general ophthalmologists. The AMAF method showed more changes in FPs than the classical side-by-side comparison method. Regarding inter- and intrareader agreements, agreement for the glaucoma experts was best using the AMAF method, but for the general ophthalmologists agreement was best using the side-by-side comparison method.

  13. Spectrum analysis of the power line flicker induced by the electrical test of the prototype Booster dipole

    International Nuclear Information System (INIS)

    Meth, M.

    1992-01-01

    Testing of the prototype Booster dipole magnet at full current produced measurable disturbances of the beam position at the National Synchrotron Light Source. Power for the magnet and the NSLS are distributed from three substation transformers at Temple Place. Normally the substation configuration is for two independent 13.8 KV buses, derived from the 69 KV LILCO distribution. The buses are connected through a circuit breaker that is normally open circuited. Power for the magnet test is derived from one of the 13.8 KV buses and power for the NSLS is derived from the second bus. Coupling of the pulsating magnet load and the NSLS is at the 69 KV level. However, on the days that the interference was first observed at the NSLS only one-half of the substation transformers at Temple Place were in service. The 13.8 KV tie breaker was closed and the full substation load was supplied from this common bus. Thus the coupling between the pulsating magnet load and the NSLS was at the 13.8 KV level. Establishing the normal two bus configurations at Temple Place appeared to reduce the disturbance. These events suggested a controlled experiment to measure the magnet power swing and the induced powerline flicker; and from these measurements project the flicker on the lab site generated by the Booster operating at full energy. This experiment could corroborate the validity of the electrical models used in analyzing the power flow from the LILCO power grid and its distribution on the Lab site described in Accelerator Division Technical Note 220

  14. Compilation of Published PM2.5 Emission Rates for Cooking, Candles and Incense for Use in Modeling of Exposures in Residences

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Tianchao [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-08-01

    recent analysis of health impacts from air pollutant inhalation in homes found that PM2.5 is the most damaging at the population level. Chronic exposure to elevated PM2.5 has the potential to damage human respiratory systems, and may result in premature death. PM2.5 exposures in homes can be mitigated through various approaches including kitchen exhaust ventilation, filtration, indoor pollutant source reduction and designing ventilation systems to reduce the entry of PM2.5 from outdoors. Analysis of the potential benefits and costs of various approaches can be accomplished using computer codes that simulate the key physical processes including emissions, dilution and ventilation. The largest sources of PM2.5 in residences broadly are entry from outdoors and emissions from indoor combustion. The largest indoor sources are tobacco combustion (smoking), cooking and the burning of candles and incense. Data on the magnitude of PM2.5 and other pollutant emissions from these events and processes are required to conduct simulations for analysis. The goal of this study was to produce a database of pollutant emission rates associated with cooking and the burning of candles and incense. The target use of these data is for indoor air quality modeling.

  15. Experimental and numerical study of impact of voltage fluctuate, flicker and power factor wave electric generator to local distribution

    Science.gov (United States)

    Hadi, Nik Azran Ab; Rashid, Wan Norhisyam Abd; Hashim, Nik Mohd Zarifie; Mohamad, Najmiah Radiah; Kadmin, Ahmad Fauzan

    2017-10-01

    Electricity is the most powerful energy source in the world. Engineer and technologist combined and cooperated to invent a new low-cost technology and free carbon emission where the carbon emission issue is a major concern now due to global warming. Renewable energy sources such as hydro, wind and wave are becoming widespread to reduce the carbon emissions, on the other hand, this effort needs several novel methods, techniques and technologies compared to coal-based power. Power quality of renewable sources needs in depth research and endless study to improve renewable energy technologies. The aim of this project is to investigate the impact of renewable electric generator on its local distribution system. The power farm was designed to connect to the local distribution system and it will be investigated and analyzed to make sure that energy which is supplied to customer is clean. The MATLAB tools are used to simulate the overall analysis. At the end of the project, a summary of identifying various voltage fluctuates data sources is presented in terms of voltage flicker. A suggestion of the analysis impact of wave power generation on its local distribution is also presented for the development of wave generator farms.

  16. Quantum fluctuations of the Coulomb potential as a source of flicker noise: the influence of external electric field

    International Nuclear Information System (INIS)

    Kazakov, Kirill A

    2006-01-01

    Fluctuations of the electromagnetic field produced by quantized matter in an external electric field are investigated. A general expression for the power spectrum of fluctuations is derived within the long-range expansion. It is found that in the whole measured frequency band, the power spectrum of fluctuations exhibits an inverse frequency dependence. A general argument is given showing that for all practically relevant values of the electric field, the power spectrum of induced fluctuations is proportional to the field strength squared. As an illustration, the power spectrum is calculated explicitly using a kinetic model with a relaxation-type collision term. Finally, it is shown that the magnitude of fluctuations produced by a sample generally has a Gaussian distribution around its mean value, and its dependence on the sample geometry is determined. In particular, it is demonstrated that for geometrically similar samples the power spectrum is inversely proportional to the sample volume. Application of the results obtained to the problem of flicker noise is discussed

  17. Analysis of EEG signal by flicker-noise spectroscopy: identification of right-/left-hand movement imagination.

    Science.gov (United States)

    Broniec, A

    2016-12-01

    Flicker-noise spectroscopy (FNS) is a general phenomenological approach to analyzing dynamics of complex nonlinear systems by extracting information contained in chaotic signals. The main idea of FNS is to describe an information hidden in correlation links, which are present in the chaotic component of the signal, by a set of parameters. In the paper, FNS is used for the analysis of electroencephalography signal related to the hand movement imagination. The signal has been parametrized in accordance with the FNS method, and significant changes in the FNS parameters have been observed, at the time when the subject imagines the movement. For the right-hand movement imagination, abrupt changes (visible as a peak) of the parameters, calculated for the data recorded from the left hemisphere, appear at the time corresponding to the initial moment of the imagination. In contrary, for the left-hand movement imagination, the meaningful changes in the parameters are observed for the data recorded from the right hemisphere. As the motor cortex is activated mainly contralaterally to the hand, the analysis of the FNS parameters allows to distinguish between the imagination of the right- and left-hand movement. This opens its potential application in the brain-computer interface.

  18. LARGER PLANET RADII INFERRED FROM STELLAR ''FLICKER'' BRIGHTNESS VARIATIONS OF BRIGHT PLANET-HOST STARS

    International Nuclear Information System (INIS)

    Bastien, Fabienne A.; Stassun, Keivan G.; Pepper, Joshua

    2014-01-01

    Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, log g. Recent work has demonstrated that the short-timescale brightness variations ( f licker ) of stars can be used to measure log g to a high accuracy of ∼0.1-0.2 dex. Here, we use flicker measurements of 289 bright (Kepmag < 13) candidate planet-hosting stars with T eff = 4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, Malmquist bias contaminates the stellar sample with evolved stars: nearly 50% of the bright planet-host stars are subgiants. As a result, the stellar radii, and hence the radii of the planets orbiting these stars, are on average 20%-30% larger than previous measurements had suggested

  19. Material characterization of the clay bonded silicon carbide candle filters and ash formations in the W-APF system after 500 hours of hot gas filtration at AEP. Appendix to Advanced Particle Filter: Technical progress report No. 11, January--March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Alvin, M.A.

    1993-04-05

    (1) After 500 hours of operation in the pressurized fluidized-bed combustion gas environment, the fibrous outer membrane along the clay bonded silicon carbide Schumacher Dia Schumalith candles remained intact. The fibrous outer membrane did not permit penetration of fines through the filter wall. (2) An approximate 10-15% loss of material strength occurred within the intact candle clay bonded silicon carbide matrix after 500 hours of exposure to the PFBC gas environment. A relatively uniform strength change resulted within the intact candles throughout the vessel (i.e., top to bottom plenums), as well as within the various cluster ring positions (i.e., outer versus inner ring candle filters). A somewhat higher loss of material strength, i.e., 25% was detected in fractured candle segments removed from the W-APF ash hopper. (3) Sulfur which is present in the pressurized fluidized-bed combustion gas system induced phase changes along the surface of the binder which coats the silicon carbide grains in the Schumacher Dia Schumalith candle filter matrix.

  20. Evidence of Flicker-Induced Functional Hyperaemia in the Smallest Vessels of the Human Retinal Blood Supply.

    Directory of Open Access Journals (Sweden)

    Angelina Duan

    Full Text Available Regional changes in blood flow are initiated within neural tissue to help fuel local differences in neural activity. Classically, this response was thought to arise only in larger arterioles and venules. However, recently, it has been proposed that a the smallest vessels of the circulation make a comparable contribution, and b the response should be localised intermittently along such vessels, due to the known distribution of contractile mural cells. To assess these hypotheses in human neural tissue in vivo, we imaged the retinal microvasculature (diameters 3-28 μm non-invasively, using adaptive optics, before and after delivery of focal (360 μm patches of flickering visible light. Our results demonstrated a definite average response in 35% of all vessel segments analysed. In these responding vessels, the magnitude of proportional dilation (mean ± SEM for pre-capillary arterioles 13 ± 5%, capillaries 31 ± 8%, and post-capillary venules 10 ± 3% is generally far greater than the magnitudes we and others have measured in the larger retinal vessels, supporting proposition a above. The dilations observed in venules were unexpected based on previous animal work, and may be attributed either to differences in stimulus or species. Response heterogeneity across the network was high; responses were also heterogeneous along individual vessels (45% of vessel segments showed demonstrable locality in their response. These observations support proposition b above. We also observed a definite average constriction across 7% of vessel segments (mean ± SEM constriction for capillaries -16 ± 3.2%, and post-capillary venules -18 ± 12%, which paints a picture of dynamic redistribution of flow throughout the smallest vessel networks in the retina in response to local, stimulus-driven metabolic demand.

  1. Persistence of critical flicker fusion frequency impairment after a 33 mfw SCUBA dive: evidence of prolonged nitrogen narcosis?

    Science.gov (United States)

    Balestra, C; Lafère, P; Germonpré, P

    2012-12-01

    One of the possible risks incurred while diving is inert gas narcosis (IGN), yet its mechanism of action remains a matter of controversy. Although providing insights in the basic mechanisms of IGN, research has been primarily limited to animal studies. A human study, in real diving conditions, was needed. Twenty volunteers within strict biometrical criteria (male, age 30-40 years, BMI 20-23, non smoker) were selected. They performed a no-decompression dive to a depth of 33 mfw for 20 min and were assessed by the means of critical flicker fusion frequency (CFFF) measurement before the dive, during the dive upon arriving at the bottom, 5 min before the ascent, and 30 min after surfacing. After this late measurement, divers breathed oxygen for 15 min and were assessed a final time. Compared to the pre-dive value the mean value of each measurement was significantly different (p < 0.001). An increase of CFFF to 104 ± 5.1 % upon arriving to the bottom is followed by a decrease to 93.5 ± 4.3 %. This impairment of CFFF persisted 30 min after surfacing, still decreased to 96.3 ± 8.2 % compared to pre-dive CFFF. Post-dive measures made after 15 min of oxygen were not different from control (without nitrogen supersaturation), 124.4 ± 10.8 versus 124.2 ± 3.9 %. This simple study suggests that IGN (at least partially) depends on gas-protein interactions and that the cerebral impairment persists for at least 30 min after surfacing. This could be an important consideration in situations where precise and accurate judgment or actions are essential.

  2. Reliability characterization of SiON and MGHK MOSFETs using flicker noise and its correlation with the bias temperature instability

    Science.gov (United States)

    Samnakay, Rameez; Balandin, Alexander A.; Srinivasan, Purushothaman

    2017-09-01

    Bias temperature instability (BTI) is one of the critical device degradation mechanisms in poly-Si/SiON and metal gate/high-k complementary metal-oxide-semiconductor (CMOS) technologies. Using the pre- and post-BTI flicker noise measurements, we investigated the bulk trap density, Nt, in both of these technologies. The low-frequency noise spectra were predominantly of 1/fγ type with γ < 1 for NMOS and ∼1 for PMOS. For SiON based technologies, the lower VTH degradation due to PBTI was noticed while considerable VTH degradation was observed for NBTI in both SiON and MGHK technologies. Both MGHK and SiON pFETs show a clear increase in the effective volume trap density, Nt, after NBTI. The increase in Nt in MGHK n-MOSFETs during PBTI is markedly higher than that in MGHK p-MOSFETs during NBTI. From 2012-2016 he was a Research Assistant with the Nano-Device Laboratory at the University of California - Riverside, as well as a member of the Quality and Reliability engineering team at Globalfoundries, Inc. during the summer of 2014. He has currently authored or co-authored 10 journal publications and numerous conference presentations. His current research interests include 1/f noise in high-k dielectrics and fabricated 2D van der Waal thin-film devices Mr. Samnakay's awards and honors include the Dean's Distinguished Fellowship Award (University of California-Riverside) and induction into the IEEE-HKN honors society. He also serves as a reviewer for 6 journals including Applied Physics Letters, Journal of Physics: Condensed Matter and Nanotechnology journals.

  3. Radial velocity variations of photometrically quiet, chromospherically inactive Kepler stars: A link between RV jitter and photometric flicker

    International Nuclear Information System (INIS)

    Bastien, Fabienne A.; Stassun, Keivan G.; Pepper, Joshua; Wright, Jason T.; Aigrain, Suzanne; Basri, Gibor; Johnson, John A.; Howard, Andrew W.; Walkowicz, Lucianne M.

    2014-01-01

    We compare stellar photometric variability, as measured from Kepler light curves by Basri et al., with measurements of radial velocity (RV) rms variations of all California Planet Search overlap stars. We newly derive rotation periods from the Kepler light curves for all of the stars in our study sample. The RV variations reported herein range from less than 4 to 135 m s –1 , yet the stars all have amplitudes of photometric variability less than 3 mmag, reflecting the preference of the RV program for chromospherically 'quiet' stars. Despite the small size of our sample, we find with high statistical significance that the RV rms manifests strongly in the Fourier power spectrum of the light curve: stars that are noisier in RV have a greater number of frequency components in the light curve. We also find that spot models of the observed light curves systematically underpredict the observed RV variations by factors of ∼2-1000, likely because the low-level photometric variations in our sample are driven by processes not included in simple spot models. The stars best fit by these models tend to have simpler light curves, dominated by a single relatively high-amplitude component of variability. Finally, we demonstrate that the RV rms behavior of our sample can be explained in the context of the photometric variability evolutionary diagram introduced by Bastien et al. We use this diagram to derive the surface gravities of the stars in our sample, revealing many of them to have moved off the main sequence. More generally, we find that the stars with the largest RV rms are those that have evolved onto the 'flicker floor' sequence in that diagram, characterized by relatively low amplitude but highly complex photometric variations which grow as the stars evolve to become subgiants.

  4. Fatiga del sistema nervioso mediante umbrales Flicker Fusion después de una prueba de ultrarresistencia por relevos de 200 km

    Directory of Open Access Journals (Sweden)

    Vicente J. Clemente Suárez

    2010-01-01

    Full Text Available La investigación en pruebas de ultrarresistencia se ha centrado en el estudio de la respuesta orgánica a través del estudio de diversos parámetros fisiológicos y de composición corporal. El estudio de la influencia en la función cognitiva y el sistema nervioso central no se ha abordado en estas especialidades aunque diversos autores han estudiado la fatiga del sistema nervioso central en sujetos desentrenados y ante diferentes estímulos de ejercicio (Davranche & Audifren, 2004; Gibson & Noakes, 2004; Presland et al., 2005 mediante los Umbrales Flicker Fusion (UFF. El presente estudio pretende estudiar los cambios en los umbrales Flicker Fusion antes y después de realizar una prueba de ultrarresistencia por relevos de 200 km, como medio para valorar la fatiga del sistema nervioso central. La muestra la componen 7 corredores (33±6,9 años; 172,6±3 cm; 69,3±8,7 kg; 23,2±1,7 kg/m²; 13,0±2,6% grasa. Previo a la prueba y al finalizar el último relevo de cada corredor, se realizaron las mediciones de los UFF, cada sujeto realizó el test de UFF en tres ocasiones. Los resultados muestran cómo los UFF aumentan después de la prueba aunque no significativamente. Con estos resultados podemos concluir que una prueba de ultrarresistencia por relevos de 200 km no parece que genere fatiga en el Sistema Nervioso Central medida con el sistema Flicker Fusion, ni altere la función cognitiva al no modificarse los UFF.

  5. Flicker cone function in normal and day blind sheep: a large animal model for human achromatopsia caused by CNGA3 mutation.

    Science.gov (United States)

    Ezra-Elia, Raaya; Banin, Eyal; Honig, Hen; Rosov, Alexander; Obolensky, Alexey; Averbukh, Edward; Hauswirth, William W; Gootwine, Elisha; Ofri, Ron

    2014-12-01

    Recently we reported on day blindness in sheep caused by a mutation in the CNGA3 gene, thus making affected sheep a naturally occurring large animal model for therapeutic intervention in CNGA3 achromatopsia patients. The purpose of this study was to characterize flicker cone function in normal and day blind sheep, with the aim of generating a normative data base for ongoing gene therapy studies. Electoretinographic (ERG) cone responses were evoked with full-field conditions in 10 normal, 6 heterozygous carriers and 36 day blind sheep. Following light adaptation (10 min, 30 cd/m(2)), responses were recorded at four increasing light intensities (1, 2.5, 5 and 10 cd s/m(2)). At each of these intensities, a single photopic flash response followed by 8 cone flicker responses (10-80 Hz) was recorded. Results were used to generate a normative data base for the three groups. Differences between day blind and normal control animals were tested in two age-matched groups (n = 10 per group). The normal sheep cone ERG wave is bipartite in nature, with critical flicker fusion frequency (CFF) >80 Hz. In all four flash intensities, the single photopic flash a-wave and b-wave amplitudes were significantly lower (p < 0.005), and implicit times significantly delayed (p < 0.0001), in day blind animals. In all four flash intensities, CFF values were significantly lower (p < 0.0001) in day blind sheep. Cone function is severely depressed in day blind sheep. Our results will provide a normative data base for ongoing gene therapy studies.

  6. Intrinsic microstrains and normal-phase flicker noise in YBa2Cu3O7 epitaxial films grown on various substrates

    International Nuclear Information System (INIS)

    Bobyl, A.V.; Gaevski, M.E.; Karmanenko, S.F.; Kutt, R.N.; Suris, R.A.; Khrebtov, I.A.; Tkachenko, A.D.; Morosov, A.I.

    1997-01-01

    Local measurements of structural characteristics such as intrinsic microstrain along the c axis of the lattice var-epsilon=δc/c and its mean square fluctuation left-angle var-epsilon right-angle, oxygen deficiency x, cation composition, etc. were performed on epitaxial YBa 2 Cu 3 O 7 films grown on various substrates (MgO, BaSrTiO 3 /MgO, SrTiO 3 , LaAlO 3 , ZrO 2 /Si, Al 2 O 3 ). A number of film microstrips were fabricated and the normalized flicker noise intensity (Hooge parameter α) and the resistivity ρ at 300 K were measured at each characterized point. A theoretical model was developed that explains the observed first growth of α with left-angle var-epsilon right-angle and the well-known high level of the normal-phase flicker noise in various high temperature superconducting compounds. Comparison of the experimental and simulated dependence of α on left-angle var-epsilon right-angle, frequency, and temperature permits one to determine numerically the theoretical parameters of the double-well potential with minima located at the chain (O1) and empty (O5) oxygen lattice positions of the CuO plane. copyright 1997 American Institute of Physics

  7. A method for achieving an order-of-magnitude increase in the temporal resolution of a standard computer monitor

    Science.gov (United States)

    Fiesta, Matthew P.; Eagleman, David M.

    2008-01-01

    As the frequency of a flickering light is increased, the perception of flicker is replaced by the perception of steady light at what is known as the critical flicker fusion threshold (CFFT). This threshold provides a useful measure of the brain’s information processing speed, and has been used in medicine for over a century both for diagnostic and drug efficacy studies. However, the hardware for presenting the stimulus has not advanced to take advantage of computers, largely because the refresh rates of typical monitors are too slow to provide fine-grained changes in the alternation rate of a visual stimulus. For example, a cathode ray tube (CRT) computer monitor running at 100 Hz will render a new frame every 10 msec, thus restricting the period of a flickering stimulus to multiples of 20 msec. These multiples provide a temporal resolution far too low to make precise threshold measurements, since typical CFFT values are in the neighborhood of 35 msec. We describe here a simple and novel technique to enable alternating images at several closely-spaced periods on a standard monitor. The key to our technique is to programatically control the video card to dynamically reset the refresh rate of the monitor. Different refresh rates allow slightly different frame durations; this can be leveraged to vastly increase the resolution of stimulus presentation times. This simple technique opens new inroads for experiments on computers that require more finely-spaced temporal resolution than a monitor at a single, fixed refresh rate can allow. PMID:18640156

  8. Standardization and evaluation of the CAMP reaction for the prompt, presumptive identification of Streptococcus agalactiae (Lancefield group B) in clinical material.

    Science.gov (United States)

    Darling, C L

    1975-02-01

    Primary cultures of clinical material were screened for the presence of colonies suspected of being Streptococcus agalactiae (Lancefield group B). Sixty-three such cultures and 108 other isolates of beta-hemolytic streptococci (groups A, C, and G), encountered during the first 3 months of the investigation, were studied by Lancefield grouping, sodium hippurate hydrolysis, and a standardized CAMP test. All streptococci were inoculated perpendicularly to streaks of a beta-toxin-producing staphylococcus on sheep blood agar plates and incubated aerobically in a candle jar and anaerobically at 37 C. Plates were examined after 5 to 6 and 18 h of incubation. The production of a distinct "arrowhead" of hemolysis was indicative of a positive CAMP reaction. All group B streptococci produced a positive CAMP reaction in the candle jar or anaerobically, usually within 5 to 6 h, and aerobically after 18 h of incubation. All group A streptococci produced a positive reaction only under anaerobic conditions. Groups C and G streptococci were negative under all atmospheres. The CAMP reaction is a prompt and reliable procedure for the presumptive identification of group B streptococci when a candle jar atmosphere is used during incubation.

  9. The Flickering Global City

    Directory of Open Access Journals (Sweden)

    Eric Slater

    2015-08-01

    Full Text Available This article explores new dimensions of the global city in light of the correlation between hegemonic transition and the prominence of financial centers. It counterposes Braudel’s historical sequence of dominant cities to extant approaches in the literature, shifting the emphasis from a convergence of form and function to variations in history and structure. The marked increase of finance in the composition of London, New York and Tokyo has paralleled each city’s occupation of a distinct niche in world financial markets: London is the principal center of currency exchange, New York is the primary equities market, and Tokyo is the leader in international banking. This division expresses the progression of world-economies since the nineteenth century and unfolds in the context of the present hegemonic transition. By combining world-historical and city-centered approaches, the article seeks to reframe the global city and overcome the limits inherent in the paradigm of globalization.

  10. Application of neural classifier to risk recognition of sustained ventricular tachycardia and flicker in patients after myocardial infarction based on high-resolution electrocardiography

    Science.gov (United States)

    Wydrzyński, Jacek; Jankowski, Stanisław; Piątkowska-Janko, Ewa

    2008-01-01

    This paper presents the application of neural networks to the risk recognition of sustained ventricular tachycardia and flicker in patients after myocardial infarction based on high-resolution electrocardiography. This work is based on dataset obtained from the Medical University of Warsaw. The studies were performed on one multiclass classifier and on binary classifiers. For each case the optimal number of hidden neurons was found. The effect of data preparation: normalization and the proper selection of parameters was considered, as well as the influence of applied filters. The best neural classifier contains 5 hidden neurons, the input ECG signal is represented by 8 parameters. The neural network classifier had high rate of successful recognitions up to 90% performed on the test data set.

  11. Reduced Subthreshold Characteristics and Flicker Noise of an AlGaAs/InGaAs PHEMT Using Liquid Phase Deposited TiO2 as a Gate Dielectric

    Directory of Open Access Journals (Sweden)

    Kai-Yuen Lam

    2016-10-01

    Full Text Available This study presents the fabrication and improved properties of an AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor (MOS-PHEMT using liquid phase deposited titanium dioxide (LPD-TiO2 as a gate dielectric. Sulfur pretreatment and postoxidation rapid thermal annealing (RTA were consecutively employed before and after the gate dielectric was deposited to fill dangling bonds and therefore release interface trapped charges. Compared with a benchmark PHEMT, the AlGaAs/InGaAs MOS-PHEMT using LPD-TiO2 exhibited larger gate bias operation, higher breakdown voltage, suppressed subthreshold characteristics, and reduced flicker noise. As a result, the device with proposed process and using LPD-TiO2 as a gate dielectric is promising for high-speed applications that demand little noise at low frequencies.

  12. The effect of voluntary fasting and dehydration on flicker-induced retinal vascular dilation in a healthy individual: a case report

    Directory of Open Access Journals (Sweden)

    Heitmar Rebekka

    2008-05-01

    Full Text Available Abstract Introduction Dynamic retinal vessel analysis represents a well-established method for the assessment of vascular reactivity during both normal conditions and after various provocations. We present a case where the subject showed abnormal retinal vessel reactivity after fasting voluntarily for 20 hours. Case presentation A healthy, 21-year-old man who fasted voluntarily for 20 hours exhibited abnormal retinal vascular reactivity (dilation and constriction after flicker provocation as measured using the Dynamic Retinal Vessel Analyser (Imedos, Jena, Germany. Conclusion The abnormal vascular reactivity induced by fasting was significant; abnormal levels of important nutrients due to fasting and dehydration could play a role through altering the concentration of vasoactive substances such as nitric oxide. This hypothesis needs further investigation.

  13. Investigation of the flickering of La{sub 2}O{sub 3} and ThO{sub 2} doped tungsten cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Hoebing, T.; Hermanns, P.; Bergner, A.; Ruhrmann, C.; Mentel, J.; Awakowicz, P. [Ruhr University Bochum, Electrical Engineering and Plasma Technology, 44780 Bochum (Germany); Traxler, H.; Wesemann, I.; Knabl, W. [Plansee SE, Metallwerk-Plansee-Str. 71, 6600 Reutte (Austria)

    2015-07-14

    Short-arc lamps are equipped with tungsten electrodes due to their ability to withstand a high thermal load during operation. Nominal currents of more than one hundred amperes lead to a cathode tip temperature near the melting point of tungsten. To reduce the electrode temperature and, thereby, to increase the maintenance of such lamps, ThO{sub 2} or tentatively La{sub 2}O{sub 3} are added to the electrode material. They generate a reduced work function by establishing a monolayer of emitter atoms on the tungsten surface. Emitter enrichments on the lateral surface of doped cathodes are formed. They are traced back to transport mechanisms of emitter oxides in the interior of the electrode and on the electrode surface in dependence of the electrode temperature and to the redeposition of vaporized and ionized emitter atoms onto the cathode tip by the electric field in front. The investigation is undertaken by means of glow discharge mass spectrometry, scanning electron microscope images, energy dispersive x-ray spectroscopy, and through measurements of the optical surface emissivity. The effect of emitter enrichments on the stability of the arc attachment is presented by means of temporally resolved electrode temperature measurements and by measurements of the luminous flux from the cathode-near plasma. They show that the emitter enrichments on the lateral surface of the cathode are attractive for the arc attachment if the emitter at the cathode tip is depleted. In this case, it moves along the lateral surface from the cathode tip to sections of the cathode with a reduced work function. It induces a temporary variation of the cathode tip temperature and of the light intensity from the cathode-near plasma, a so-called flickering. In particular, in case of lanthanated cathodes, strong flickering is observed.

  14. Flicker perimetry in healthy subjects: influence of age and gender, learning effect and short-term fluctuation Perimetria "flicker" em indivíduos normais: influência da idade e sexo, efeito aprendizado e flutuação a curto prazo

    Directory of Open Access Journals (Sweden)

    Luciana Bernardi

    2007-02-01

    Full Text Available PURPOSE: To determine the mean critical fusion frequency and the short-term fluctuation, to analyze the influence of age, gender, and the learning effect in healthy subjects undergoing flicker perimetry. METHODS: Study 1 - 95 healthy subjects underwent flicker perimetry once in one eye. Mean critical fusion frequency values were compared between genders, and the influence of age was evaluated using linear regression analysis. Study 2 - 20 healthy subjects underwent flicker perimetry 5 times in one eye. The first 3 sessions were separated by an interval of 1 to 30 days, whereas the last 3 sessions were performed within the same day. The first 3 sessions were used to investigate the presence of a learning effect, whereas the last 3 tests were used to calculate short-term fluctuation. RESULTS: Study 1 - Linear regression analysis demonstrated that mean global, foveal, central, and critical fusion frequency per quadrant significantly decreased with age (p0.05, with the exception of the central area and inferonasal quadrant (p=0.049 and p=0.011, respectively, where the values were lower in females. Study 2 - Mean global (p=0.014, central (p=0.008, and peripheral (p=0.03 critical fusion frequency were significantly lower in the first session compared to the second and third sessions. The mean global short-term fluctuation was 5.06±1.13 Hz, the mean interindividual and intraindividual variabilities were 11.2±2.8% and 6.4±1.5%, respectively. CONCLUSION: This study suggests that, in healthy subjects, critical fusion frequency decreases with age, that flicker perimetry is associated with a learning effect, and that a moderately high short-term fluctuation is expected.OBJETIVOS: Determinar os valores médios da freqüência crítica de fusão e a flutuação a curto prazo, analisar a influência da idade, sexo e o efeito aprendizado na perimetria "flicker". MÉTODOS: Estudo 1 - 96 indivíduos normais foram submetidos à perimetria "flicker" uma vez em

  15. Cherry-Slush-Candling Apparatus

    Science.gov (United States)

    Stephens, James B.; Weiss, James R.; Hoover, Gordon

    1996-01-01

    Proposed infrared-scanning apparatus for use in bakeries making cherry pies detect cherry pits remaining in cherry slush after pitting process. Pits detected via their relative opacity to infrared radiation.

  16. Memorial Candles: Beauty as Consolation

    Directory of Open Access Journals (Sweden)

    Mindy Weisel

    2011-01-01

    Full Text Available Do we ever get used to the feelings of loss? Time supposedly heals all wounds. Does it really? Or do we take that time and take that loss and turn it into something else, something that takes the shape and the form of our loss. Is this perhaps the source of the deepest art? Is it the art that actually gives our lives meaning? There are clearly feelings that are beyond comprehension. It is these feelings that are put into the music, poetry, painting, photography, prose, and theater that enrich our lives, and that are addressed in this book. The women in “Daughters of Absence” all have one thing in common: as daughters of Holocaust survivors they have found a strong voice through their work. For these creative women, their work has been both life force and life saver.

  17. ['Gold standard', not 'golden standard'

    NARCIS (Netherlands)

    Claassen, J.A.H.R.

    2005-01-01

    In medical literature, both 'gold standard' and 'golden standard' are employed to describe a reference test used for comparison with a novel method. The term 'gold standard' in its current sense in medical research was coined by Rudd in 1979, in reference to the monetary gold standard. In the same

  18. Accounting standards

    NARCIS (Netherlands)

    Stellinga, B.; Mügge, D.

    2014-01-01

    The European and global regulation of accounting standards have witnessed remarkable changes over the past twenty years. In the early 1990s, EU accounting practices were fragmented along national lines and US accounting standards were the de facto global standards. Since 2005, all EU listed

  19. Reliability of a commercially available heterochromatic flicker photometer, the MPS2, for measuring the macular pigment optical density of a Japanese population.

    Science.gov (United States)

    Obana, Akira; Gohto, Yuko; Moriyama, Takatoshi; Seto, Takahiko; Sasano, Hiroyuki; Okazaki, Shigetoshi

    2018-03-28

    The macular pigment optical density (MPOD) of a Japanese population was measured using a commercially based heterochromatic flicker photometer, the Macular Pigment Screener (MPS2). The objective of the study was to evaluate the accuracy and test-retest reliability of the MPS2 in Asian pigmented eyes. Experimental study to validate the medical instrument in humans. Twenty-four healthy Japanese participants with no systemic or eye diseases (men: 13, women: 11; mean [SD] age 38.6 [10.9 years]) were included. The concordance of the MPOD, obtained using the MPS2 and Macular Metrics II (MM2), and the test-retest reliability were examined. Determination of the MPOD was unsuccessful in 1 participant; thus, the MPOD of 23 participants was analyzed. The mean (SD) MPOD measured with the detail-mode of the MPS2 was 0.63 (0.18) and with that of the MM2, it was 0.72 (0.23). The former was significantly lower than the latter (P = .003, paired t test). The MPOD measured with the MPS2 and the MM2 showed good concordance (r = 0.79, P < .001, Pearson product moment correlation). Bland-Altman analyses showed no systematic errors between the MPS2 and the MM2. The intraclass correlation coefficient over 5 measurement times with the detail-mode of the MPS2 was 0.80, and the mean coefficient of variation was 9.4%. The high concordance with the MM2 and good test-retest reliability found by this study suggest that the MPS2 is acceptable for use in a Japanese population. However, the mean MPOD yielded by the MPS2 was significantly lower than that yielded by the MM2. Therefore, the MPS2 and MM2 are not interchangeable in a single study.

  20. FLICKERING OF 1.3 cm SOURCES IN SGR B2: TOWARD A SOLUTION TO THE ULTRACOMPACT H II REGION LIFETIME PROBLEM

    Energy Technology Data Exchange (ETDEWEB)

    De Pree, C. G.; Monsrud, A. [Agnes Scott College, 141 East College Avenue, Decatur, GA 30030 (United States); Peters, T. [Institut für Theoretische Physik, Universität Zürich, CH-8057 Zürich (Switzerland); Mac Low, M.-M. [American Museum of Natural History, New York, NY 10024 (United States); Wilner, D. J.; Keto, E. R. [Harvard-Smithsonian CfA, Cambridge, MA 02138 (United States); Goss, W. M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Galván-Madrid, R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Klessen, R. S. [Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany)

    2014-02-01

    Accretion flows onto massive stars must transfer mass so quickly that they are themselves gravitationally unstable, forming dense clumps and filaments. These density perturbations interact with young massive stars, emitting ionizing radiation, alternately exposing and confining their H II regions. As a result, the H II regions are predicted to flicker in flux density over periods of decades to centuries rather than increase monotonically in size as predicted by simple Spitzer solutions. We have recently observed the Sgr B2 region at 1.3 cm with the Very Large Array in its three hybrid configurations (DnC, CnB, and BnA) at a resolution of ∼0.''25. These observations were made to compare in detail with matched continuum observations from 1989. At 0.''25 resolution, Sgr B2 contains 41 ultracompact (UC) H II regions, 6 of which are hypercompact. The new observations of Sgr B2 allow comparison of relative peak flux densities for the H II regions in Sgr B2 over a 23 year time baseline (1989-2012) in one of the most source-rich massive star forming regions in the Milky Way. The new 1.3 cm continuum images indicate that four of the 41 UC H II regions exhibit significant changes in their peak flux density, with one source (K3) dropping in peak flux density, and the other three sources (F10.303, F1, and F3) increasing in peak flux density. The results are consistent with statistical predictions from simulations of high mass star formation, suggesting that they offer a solution to the lifetime problem for UC H II regions.

  1. Kinetic structure of large-conductance Ca2+-activated K+ channels suggests that the gating includes transitions through intermediate or secondary states. A mechanism for flickers.

    Science.gov (United States)

    Rothberg, B S; Magleby, K L

    1998-06-01

    Mechanisms for the Ca2+-dependent gating of single large-conductance Ca2+-activated K+ channels from cultured rat skeletal muscle were developed using two-dimensional analysis of single-channel currents recorded with the patch clamp technique. To extract and display the essential kinetic information, the kinetic structure, from the single channel currents, adjacent open and closed intervals were binned as pairs and plotted as two-dimensional dwell-time distributions, and the excesses and deficits of the interval pairs over that expected for independent pairing were plotted as dependency plots. The basic features of the kinetic structure were generally the same among single large-conductance Ca2+-activated K+ channels, but channel-specific differences were readily apparent, suggesting heterogeneities in the gating. Simple gating schemes drawn from the Monod- Wyman-Changeux (MWC) model for allosteric proteins could approximate the basic features of the Ca2+ dependence of the kinetic structure. However, consistent differences between the observed and predicted dependency plots suggested that additional brief lifetime closed states not included in MWC-type models were involved in the gating. Adding these additional brief closed states to the MWC-type models, either beyond the activation pathway (secondary closed states) or within the activation pathway (intermediate closed states), improved the description of the Ca2+ dependence of the kinetic structure. Secondary closed states are consistent with the closing of secondary gates or channel block. Intermediate closed states are consistent with mechanisms in which the channel activates by passing through a series of intermediate conformations between the more stable open and closed states. It is the added secondary or intermediate closed states that give rise to the majority of the brief closings (flickers) in the gating.

  2. Communications standards

    CERN Document Server

    Stokes, A V

    1986-01-01

    Communications Standards deals with the standardization of computer communication networks. This book examines the types of local area networks (LANs) that have been developed and looks at some of the relevant protocols in more detail. The work of Project 802 is briefly discussed, along with a protocol which has developed from one of the LAN standards and is now a de facto standard in one particular area, namely the Manufacturing Automation Protocol (MAP). Factors that affect the usage of networks, such as network management and security, are also considered. This book is divided into three se

  3. Achieving Standardization

    DEFF Research Database (Denmark)

    Henningsson, Stefan

    2016-01-01

    competitive, national customs and regional economic organizations are seeking to establish a standardized solution for digital reporting of customs data. However, standardization has proven hard to achieve in the socio-technical e-Customs solution. In this chapter, the authors identify and describe what has......International e-Customs is going through a standardization process. Driven by the need to increase control in the trade process to address security challenges stemming from threats of terrorists, diseases, and counterfeit products, and to lower the administrative burdens on traders to stay...... to be harmonized in order for a global company to perceive e-Customs as standardized. In doing so, they contribute an explanation of the challenges associated with using a standardization mechanism for harmonizing socio-technical information systems....

  4. Achieving Standardization

    DEFF Research Database (Denmark)

    Henningsson, Stefan

    2014-01-01

    competitive, national customs and regional economic organizations are seeking to establish a standardized solution for digital reporting of customs data. However, standardization has proven hard to achieve in the socio-technical e-Customs solution. In this chapter, the authors identify and describe what has......International e-Customs is going through a standardization process. Driven by the need to increase control in the trade process to address security challenges stemming from threats of terrorists, diseases, and counterfeit products, and to lower the administrative burdens on traders to stay...... to be harmonized in order for a global company to perceive e-Customs as standardized. In doing so, they contribute an explanation of the challenges associated with using a standardization mechanism for harmonizing socio-technical information systems....

  5. Training Standardization

    International Nuclear Information System (INIS)

    Agnihotri, Newal

    2003-01-01

    The article describes the benefits of and required process and recommendations for implementing the standardization of training in the nuclear power industry in the United States and abroad. Current Information and Communication Technologies (ICT) enable training standardization in the nuclear power industry. The delivery of training through the Internet, Intranet and video over IP will facilitate this standardization and bring multiple benefits to the nuclear power industry worldwide. As the amount of available qualified and experienced professionals decreases because of retirements and fewer nuclear engineering institutions, standardized training will help increase the number of available professionals in the industry. Technology will make it possible to use the experience of retired professionals who may be interested in working part-time from a remote location. Well-planned standardized training will prevent a fragmented approach among utilities, and it will save the industry considerable resources in the long run. It will also ensure cost-effective and safe nuclear power plant operation

  6. Live-cell imaging of HP1α throughout the cell cycle of mouse C3H10T1/2 cells and rhythmical flickering of heterochromatin dots in interphase.

    Science.gov (United States)

    Nakagawa, Chika; Kawakita, Ai; Fukada, Takashi; Sugimoto, Kenji

    2014-01-01

    Heterochromatin protein 1 alpha (HP1α) localizes to heterochromatin in interphase and shows dynamic molecular behavior in living cells. We previously reported that during mitosis, the majority of HP1α diffused into the cytoplasm but some remained in centromere heterochromatin. Here, we further characterize the molecular behavior of HP1α throughout the cell cycle. Time-lapse imaging of DsRed-HP1α through two successive cell divisions indicated that interphase can be divided into four phases. HP1α forms heterochromatin dots in early G1, which are maintained without any apparent changes (Phase 1). However, the HP1α dots begin to diffuse into the nucleoplasm and start flickering with a rhythmical cycle (Phase 2). Then, the HP1α dots diffuse further towards the periphery of the nucleus (Phase 3), and uniformly diffuse throughout the entire nucleus (Phase 4). Rhythmical flickering of HP1α dots in the middle of interphase may be useful for following cell cycle progression in mouse living cells.

  7. Grayscale standard display function on LCD color monitors

    Science.gov (United States)

    De Monte, Denis; Casale, Carlo; Albani, Luigi; Bonfiglio, Silvio

    2007-03-01

    Currently, as a rule, digital medical systems use monochromatic Liquid Crystal Display (LCD) monitors to ensure an accurate reproduction of the Grayscale Standard Display Function (GSDF) as specified in the Digital Imaging and Communications in Medicine (DICOM) Standard. As a drawback, special panels need to be utilized in digital medical systems, while it would be preferable to use regular color panels, which are manufactured on a wide scale and are thus available at by far lower prices. The method proposed introduces a temporal color dithering technique to accurately reproduce the GSDF on color monitors without losing monitor resolution. By exploiting the characteristics of the Human Visual System (HVS) the technique ensures that a satisfactory grayscale reproduction is achieved minimizing perceivable flickering and undesired color artifacts. The algorithm has been implemented in the monitor using a low-cost Field Programmable Gate Array (FPGA). Quantitative evaluations of luminance response on a 3 Mega-pixel color monitor have shown that the compliance with the GSDF can be achieved with the accuracy level required by medical applications. At the same time the measured color deviation is below the threshold perceivable by the human eye.

  8. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  9. Relevant Standards

    Indian Academy of Sciences (India)

    .86: Ethernet over LAPS. Standard in China and India. G.7041: Generic Framing Procedure (GFP). Supports Ethernet as well as other data formats (e.g., Fibre Channel); Protocol of ... IEEE 802.3x for flow control of incoming Ethernet data ...

  10. Timing flickers across sensory modalities.

    Science.gov (United States)

    Vicario, Carmelo Mario; Rappo, Gaetano; Pepi, Anna Maria; Oliveri, Massimiliano

    2009-01-01

    In tasks requiring a comparison of the duration of a reference and a test visual cue, the spatial position of test cue is likely to be implicitly coded, providing a form of a congruency effect or introducing a response bias according to the environmental scale or its vectorial reference. The precise mechanism generating these perceptual shifts in subjective duration is not understood, although several studies suggest that spatial attentional factors may play a critical role. Here we use a duration comparison task within and across sensory modalities to examine if temporal performance is also modulated when people are exposed to spatial distractors involving different sensory modalities. Different groups of healthy participants performed duration comparison tasks in separate sessions: a time comparison task of visual stimuli during exposure to spatially presented auditory distractors; and a time comparison task of auditory stimuli during exposure to spatially presented visual distractors. We found the duration of visual stimuli biased depending on the spatial position of auditory distractors. Observers underestimated the duration of stimuli presented in the left spatial field, while there was an overestimation trend in estimating the duration of stimuli presented in the right spatial field. In contrast, timing of auditory stimuli was unaffected by exposure to visual distractors. These results support the existence of multisensory interactions between space and time showing that, in cross-modal paradigms, the presence of auditory distractors can modify visuo-temporal perception but not vice versa. This asymmetry is discussed in terms of sensory perceptual differences between the two systems.

  11. Better to light a candle than curse the darkness: illuminating spatial localization and temporal dynamics of rapid microbial growth in the rhizosphere

    Directory of Open Access Journals (Sweden)

    Patrick M Herron

    2013-09-01

    Full Text Available The rhizosphere is a hotbed of microbial activity in ecosystems, fueled by carbon compounds from plant roots. Basic questions about the location and dynamics of plant-spurred microbial growth in the rhizosphere are difficult to answer with standard, destructive soil assays mixing a multitude of microbe-scale microenvironments in a single, often sieved, sample. Soil microbial biosensors designed with the luxCDABE reporter genes fused to a promoter of interest enable continuous imaging of the microbial perception of (and response to environmental conditions in soil. We used the common soil bacterium Pseudomonas putida KT2440 as host to plasmid pZKH2 containing a fusion between the strong constituitive promoter nptII and luxCDABE (coding for light-emitting proteins from Vibrio fischeri. Experiments in liquid media demonstrated that high light production by KT2440/pZKH2 was associated with rapid microbial growth supported by high carbon availability. We applied the biosensors in microcosms filled with non-sterile soil in which corn (Zea mays L., black poplar (Populus nigra L. or tomato (Solanum lycopersicum L. was growing. We detected minimal light production from microbiosensors in the bulk soil, but biosensors reported continuously from around roots for as long as six days. For corn, peaks of luminescence were detected 1-4 and 20-35 mm along the root axis behind growing root tips, with the location of maximum light production moving farther back from the tip as root growth rate increased. For poplar, luminescence around mature roots increased and decreased on a coordinated diel rhythm, but was not bright near root tips. For tomato, luminescence was dynamic, but did not exhibit a diel rhythm, appearing in acropetal waves along roots. KT2440/pZKH2 revealed that root tips are not always the only, or even the dominant, hotspots for rhizosphere microbial growth, and carbon availability is highly variable in space and time around roots.

  12. The Dynamics of Standardization

    DEFF Research Database (Denmark)

    Brunsson, Nils; Rasche, Andreas; Seidl, David

    2012-01-01

    This paper suggests that when the phenomenon of standards and standardization is examined from the perspective of organization studies, three aspects stand out: the standardization of organizations, standardization by organizations and standardization as (a form of) organization. Following a comp...

  13. Analytical Investigation of a Flicker-Type Roll Control for a Mach Number 6 Missile with Aerodynamic Controls Over An Altitude Range of 82,000 to 282,000 feet

    Science.gov (United States)

    Lundstrom, Reginald R.; Whitman, Ruth I.

    1959-01-01

    An analytical investigation has been carried out to determine the responses of a flicker-type roll control incorporated in a missile which traverses a range of Mach number of 6.3 at an altitude of 82,000 feet to 5.26 at an altitude of 282,000 feet. The missile has 80 deg delta wings in a cruciform arrangement with aerodynamic controls attached to the fuselage near the wing trailing edge and indexed 450 to the wings. Most of the investigation was carried out on an analog computer. Results showed that roll stabilization that may be adequate for many cases can be obtained over the altitude range considered, providing that the rate factor can be changed with altitude. The response would be improved if the control deflection were made larger at the higher altitudes. lag times less than 0.04 second improve the response appreciably. Asymmetries that produce steady rolling moments can be very detrimental to the response in some cases. The wing damping made a negligible contribution to the response.

  14. The Chemical History of a Candle

    Indian Academy of Sciences (India)

    . " - J T Desaguliers (1683-1744) in his book. Course of Experimental Philosophy. Michael Faraday, who had little schooling but excellent education during his tenure as assistant to the famous Humphry Davy, went on to become one of the ...

  15. Standards for Standardized Logistic Regression Coefficients

    Science.gov (United States)

    Menard, Scott

    2011-01-01

    Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

  16. Malaysian NDT standards

    International Nuclear Information System (INIS)

    Khazali Mohd Zin

    2001-01-01

    In order to become a developed country, Malaysia needs to develop her own national standards. It has been projected that by the year 2020, Malaysia requires about 8,000 standards (Department of Standard Malaysia). Currently more than 2,000 Malaysian Standards have been gazette by the government which considerably too low before tire year 2020. NDT standards have been identified by the standard working group as one of the areas to promote our national standards. In this paper the author describes the steps taken to establish the Malaysian very own NDT standards. The project starts with the establishment of radiographic standards. (Author)

  17. The International Standards Organisation offshore structures standard

    International Nuclear Information System (INIS)

    Snell, R.O.

    1994-01-01

    The International Standards Organisation has initiated a program to develop a suite of ISO Codes and Standards for the Oil Industry. The Offshore Structures Standard is one of seven topics being addressed. The scope of the standard will encompass fixed steel and concrete structures, floating structures, Arctic structures and the site specific assessment of mobile drilling and accommodation units. The standard will use as base documents the existing recommended practices and standards most frequently used for each type of structure, and will develop them to incorporate best published and recognized practice and knowledge where it provides a significant improvement on the base document. Work on the Code has commenced under the direction of an internationally constituted sub-committee comprising representatives from most of the countries with a substantial offshore oil and gas industry. This paper outlines the background to the code and the format, content and work program

  18. What is "Standard" About the Standard Deviation

    OpenAIRE

    Newberger, Florence; Safer, Alan M.; Watson, Saleem

    2010-01-01

    The choice of the formula for standard deviation is explained in elementary statistics textbooks in various ways. We give an explanation for this formula by representing the data as a vector in $\\mathbb R^n$ and considering its distance from a central tendency vector. In this setting the "standard" formula represents a shortest distance in the standard metric. We also show that different metrics lead to different measures of central tendency.

  19. Standard Reference Tables -

    Data.gov (United States)

    Department of Transportation — The Standard Reference Tables (SRT) provide consistent reference data for the various applications that support Flight Standards Service (AFS) business processes and...

  20. Standardization and the European Standards Organisations

    Directory of Open Access Journals (Sweden)

    Marta Orviska

    2014-01-01

    Full Text Available Standardization is a relatively neglected aspect of the EU regulatory process and yet it is fundamental to that process and arguably has recently been the key vehicle in making the single market an economic reality. Yet the key standardization bodies in the EU, the ESOs, are scarcely known to the public and seldom discussed in the literature. In this article we redress this imbalance, arguing that standardization and integration are closely related concepts. We also argue that the ESOs have developed a degree of autonomy in expanding the boundaries of standardization and even in developing their own links with the rest of the world. Recent proposals put forward by the European Commission can be seen as an attempt to reduce that autonomy. These proposals emphasize the speed of, and stakeholder involvement in, standards production, which we further suggest are somewhat conflicting aims.

  1. Standards for holdup measurement

    International Nuclear Information System (INIS)

    Zucker, M.S.

    1982-01-01

    Holdup measurement, needed for material balance, depend intensively on standards and on interpretation of the calibration procedure. More than other measurements, the calibration procedure using the standard becomes part of the standard. Standards practical for field use and calibration techniques have been developed. While accuracy in holdup measurements is comparatively poor, avoidance of bias is a necessary goal

  2. Collaboration Between Multistakeholder Standards

    DEFF Research Database (Denmark)

    Rasche, Andreas; Maclean, Camilla

    Public interest in corporate social responsibility (CSR) has resulted in a wide variety of multistakeholder CSR standards in which companies can choose to participate. While such standards reflect collaborative governance arrangements between public and private actors, the market for corporate...... responsibility is unlikely to support a great variety of partly competing and overlapping standards. Increased collaboration between these standards would enhance both their impact and their adoption by firms. This report examines the nature, benefits, and shortcomings of existing multistakeholder standards...

  3. Standards, Standards, Standards: The Unintended Consequences of Widening Participation?

    Science.gov (United States)

    Stuart, Mary

    2002-01-01

    Debate over widening access to higher education is narrowing to a focus on preservation of standards. Examination of the discourses of school policy, classroom environment, and peer culture shows how these competing cultures can work against efforts to increase participation. (Contains 17 references.) (SK)

  4. Agent Standards Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation of the work herein proposed is the development of standards for software autonomous agents. These standards are essential to achieve software...

  5. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the

  6. BTS statistical standards manual

    Science.gov (United States)

    2005-10-01

    The Bureau of Transportation Statistics (BTS), like other federal statistical agencies, establishes professional standards to guide the methods and procedures for the collection, processing, storage, and presentation of statistical data. Standards an...

  7. Dental Assisting Program Standards.

    Science.gov (United States)

    Georgia Univ., Athens. Dept. of Vocational Education.

    This publication contains statewide standards for the dental assisting program in Georgia. The standards are divided into 12 categories: foundations (philosophy, purpose, goals, program objectives, availability, evaluation); admissions (admission requirements, provisional admission requirements, recruitment, evaluation and planning); program…

  8. The Distance Standard Deviation

    OpenAIRE

    Edelmann, Dominic; Richards, Donald; Vogel, Daniel

    2017-01-01

    The distance standard deviation, which arises in distance correlation analysis of multivariate data, is studied as a measure of spread. New representations for the distance standard deviation are obtained in terms of Gini's mean difference and in terms of the moments of spacings of order statistics. Inequalities for the distance variance are derived, proving that the distance standard deviation is bounded above by the classical standard deviation and by Gini's mean difference. Further, it is ...

  9. Radiological Control Technician: Standardized technician Qualification Standard

    International Nuclear Information System (INIS)

    1992-10-01

    The Qualification Standard states and defines the knowledge and skill requirements necessary for successful completion of the Radiological Control Technician Training Program. The standard is divided into three phases: Phase I concerns RCT Academic training. There are 13 lessons associated with the core academics program and 19 lessons associated with the site academics program. The staff member should sign the appropriate blocks upon successful completion of the examination for that lesson or group of lessons. In addition, facility specific lesson plans may be added to meet the knowledge requirements in the Job Performance Measures (JPM) of the practical program. Phase II concerns RCT core/site practical (JPMs) training. There are thirteen generic tasks associated with the core practical program. Both the trainer/evaluator and student should sign the appropriate block upon successful completion of the JPM. In addition, facility specific tasks may be added or generic tasks deleted based on the results of the facility job evaluation. Phase III concerns the oral examination board successful completion of the oral examination board is documented by the signature of the chairperson of the board. Upon completion of all of the standardized technician qualification requirements, final qualification is verified by the student and the manager of the Radiological Control Department and acknowledged by signatures on the qualification standard. The completed Qualification Standard shall be maintained as an official training record

  10. Quality of semantic standards

    NARCIS (Netherlands)

    Folmer, E.J.A.

    2012-01-01

    Little scientific literature addresses the issue of quality of semantic standards, albeit a problem with high economic and social impact. Our problem survey, including 34 semantic Standard Setting Organizations (SSOs), gives evidence that quality of standards can be improved, but for improvement a

  11. Automotive Technology Skill Standards

    Science.gov (United States)

    Garrett, Tom; Asay, Don; Evans, Richard; Barbie, Bill; Herdener, John; Teague, Todd; Allen, Scott; Benshoof, James

    2009-01-01

    The standards in this document are for Automotive Technology programs and are designed to clearly state what the student should know and be able to do upon completion of an advanced high-school automotive program. Minimally, the student will complete a three-year program to achieve all standards. Although these exit-level standards are designed…

  12. [Ophthalmology and standardization].

    Science.gov (United States)

    Heitz, R

    1989-01-01

    The standards are the references for quality and safety of materials, instruments and devices in ophtalmological use. The French standardisation association, "Association Française de Normalisation" (AFNOR), drafts his standards in connection with the concerned professionals. The ophthalmologists are concerned by standards of diagnostic and therapeutic instruments, intraocular and orbital implants, contact lenses, spectacle frames and glasses, and ocular protectors.

  13. Requirements of quality standards

    International Nuclear Information System (INIS)

    Mueller, J.

    1977-01-01

    The lecture traces the development of nuclear standards, codes, and Federal regulations on quality assurance (QA) for nuclear power plants and associated facilities. The technical evolution of the last twelve years, especially in the area of nuclear technology, led to different activities and regulatory initiatives, and the present result is: several nations have their own homemade standards. The lecture discusses the former and especially current activities in standard development, and gives a description of the requirements of QA-standards used in USA and Europe, especially Western Germany. Furthermore the lecture attempts to give a comparison and an evaluation of the international quality standards from the author's viewpoint. Finally the lecture presents an outlook for the future international implications of QA-standards. There is an urgent need within the nuclear industry for simplification and standardization of QA-standards. The relationship between the various standards, and the applicability of the standards need clarification and a better transparancy. To point out these problems is the purpose of the lecture. (orig.) [de

  14. Beyond the standard model

    International Nuclear Information System (INIS)

    Wilczek, F.

    1993-01-01

    The standard model of particle physics is highly successful, although it is obviously not a complete or final theory. In this presentation the author argues that the structure of the standard model gives some quite concrete, compelling hints regarding what lies beyond. Essentially, this presentation is a record of the author's own judgement of what the central clues for physics beyond the standard model are, and also it is an attempt at some pedagogy. 14 refs., 6 figs

  15. Standard Model processes

    CERN Document Server

    Mangano, M.L.; Aguilar-Saavedra, Juan Antonio; Alekhin, S.; Badger, S.; Bauer, C.W.; Becher, T.; Bertone, V.; Bonvini, M.; Boselli, S.; Bothmann, E.; Boughezal, R.; Cacciari, M.; Carloni Calame, C.M.; Caola, F.; Campbell, J.M.; Carrazza, S.; Chiesa, M.; Cieri, L.; Cimaglia, F.; Febres Cordero, F.; Ferrarese, P.; D'Enterria, D.; Ferrera, G.; Garcia i Tormo, X.; Garzelli, M.V.; Germann, E.; Hirschi, V.; Han, T.; Ita, H.; Jäger, B.; Kallweit, S.; Karlberg, A.; Kuttimalai, S.; Krauss, F.; Larkoski, A.J.; Lindert, J.; Luisoni, G.; Maierhöfer, P.; Mattelaer, O.; Martinez, H.; Moch, S.; Montagna, G.; Moretti, M.; Nason, P.; Nicrosini, O.; Oleari, C.; Pagani, D.; Papaefstathiou, A.; Petriello, F.; Piccinini, F.; Pierini, M.; Pierog, T.; Pozzorini, S.; Re, E.; Robens, T.; Rojo, J.; Ruiz, R.; Sakurai, K.; Salam, G.P.; Salfelder, L.; Schönherr, M.; Schulze, M.; Schumann, S.; Selvaggi, M.; Shivaji, A.; Siodmok, A.; Skands, P.; Torrielli, P.; Tramontano, F.; Tsinikos, I.; Tweedie, B.; Vicini, A.; Westhoff, S.; Zaro, M.; Zeppenfeld, D.; CERN. Geneva. ATS Department

    2017-06-22

    This report summarises the properties of Standard Model processes at the 100 TeV pp collider. We document the production rates and typical distributions for a number of benchmark Standard Model processes, and discuss new dynamical phenomena arising at the highest energies available at this collider. We discuss the intrinsic physics interest in the measurement of these Standard Model processes, as well as their role as backgrounds for New Physics searches.

  16. Governing through standards

    DEFF Research Database (Denmark)

    Brøgger, Katja

    This abstract adresses the ways in which new education standards have become integral to new modes of education governance. The paper explores the role of standards for accelerating the shift from national to transnational governance in higher education. Drawing on the case of higher education...... development in Scandinavia, the paper focuses on the unintended effects of the new international standards. The Bologna process was reframed and recontextualized in ways that undermined the very system it was set out to transform and govern....

  17. Arc -furnace Flicker Compensation in Ethiopia.

    African Journals Online (AJOL)

    series capacitors nor the translater scheme is appli- cable where more ... The arc furnace is of conventional design. The furnace ... power of the furnace. This reactor had three tappings and a short-circuiting switch. REQUIREMENTS OF THE COMPENSATOR. The fluctuations could be caused by the furnace on whichever ...

  18. The Standard Model course

    CERN Multimedia

    CERN. Geneva HR-RFA

    2006-01-01

    Suggested Readings: Aspects of Quantum Chromodynamics/A Pich, arXiv:hep-ph/0001118. - The Standard Model of Electroweak Interactions/A Pich, arXiv:hep-ph/0502010. - The Standard Model of Particle Physics/A Pich The Standard Model of Elementary Particle Physics will be described. A detailed discussion of the particle content, structure and symmetries of the theory will be given, together with an overview of the most important experimental facts which have established this theoretical framework as the Standard Theory of particle interactions.

  19. International hearing protector standardization

    DEFF Research Database (Denmark)

    Poulsen, Torben

    2002-01-01

    Hearing protectors shall fulfill some minimum requirements to their performance. As hearing protector manufacturers sell the products all over the world, the testing and certification of hearing protectors has become an international issue. The ISO working group WG17 under the headlines Acoustics......, Noise, produce hearing protector standards to be used at an international level. The presentation will cover the ongoing work in WG17, including the revision of existing standards (ISO 4869-1, ISO 4869-3), upcoming new standards (ISO 4869-7) and the plans and status for future standards (performance...

  20. Standardization: colorfull or dull?

    Science.gov (United States)

    van Nes, Floris L.

    2003-01-01

    After mentioning the necessity of standardization in general, this paper explains how human factors, or ergonomics standardization by ISO and the deployment of information technology were linked. Visual display standardization is the main topic; the present as well as the future situation in this field are treated, mainly from an ISO viewpoint. Some observations are made about the necessary and interesting co-operation between physicists and psychologists, of different nationality, who both may be employed by either private enterprise or governmental institutions, in determining visual display requirements. The display standard that is to succeed the present ISO standards in this area: ISO 9241-3, -7, -8 and ISO 13406-1, -2, will have a scope that is not restricted to office tasks. This means a large extension of the contexts for which display requirements have to be investigated and specified especially if mobile use of displays, under outdoor lighting conditions, is included. The new standard will be structured in such a way that it is better accessible than the present ones for different categories of standards users. The subject color in the new standard is elaborated here. A number of questions are asked as to which requirements on color rendering should be made, taking new research results into account, and how far the new standard should go in making recommendations to the display user.

  1. Standard NIM instrumentation system

    CERN Document Server

    1990-01-01

    NIM is a standard modular instrumentation system that is in wide use throughout the world. As the NIM system developed and accommodations were made to a dynamic instrumentation field and a rapidly advancing technology, additions, revisions and clarifications were made. These were incorporated into the standard in the form of addenda and errata. This standard is a revision of the NIM document, AEC Report TID- 20893 (Rev 4) dated July 1974. It includes all the addenda and errata items that were previously issued as well as numerous additional items to make the standard current with modern technology and manufacturing practice.

  2. Position paper on standardization

    International Nuclear Information System (INIS)

    1991-04-01

    The ''NPOC Strategic Plan for Building New Nuclear Plants'' creates a framework within which new standardized nuclear plants may be built. The Strategic Plan is an expression of the nuclear energy industry's serious intent to create the necessary conditions for new plant construction and operation. One of the key elements of the Strategic Plan is a comprehensive industry commitment to standardization: through design certification, combined license, first-of-a-kind engineering, construction, operation and maintenance of nuclear power plants. The NPOC plan proposes four stages of standardization in advanced light water reactors (ALWRs). The first stage is established by the ALWR Utility Requirements Document which specifies owner/operator requirements at a functional level covering all elements of plant design and construction, and many aspects of operations and maintenance. The second stage of standardization is that achieved in the NRC design certification. This certification level includes requirements, design criteria and bases, functional descriptions and performance requirements for systems to assure plant safety. The third stage of standardization, commercial standardization, carries the design to a level of completion beyond that required for design certification to enable the industry to achieve potential increases in efficiency and economy. The final stage of standardization is enhanced standardization beyond design. A standardized approach is being developed in construction practices, operating, maintenance training, and procurement practices. This comprehensive standardization program enables the NRC to proceed with design certification with the confidence that standardization beyond the regulations will be achieved. This confidence should answer the question of design detail required for design certification, and demonstrate that the NRC should require no further regulatory review beyond that required by 10 CFR Part 52

  3. 77 FR 43542 - Cost Accounting Standards: Cost Accounting Standards 412 and 413-Cost Accounting Standards...

    Science.gov (United States)

    2012-07-25

    ... Accounting Standards: Cost Accounting Standards 412 and 413--Cost Accounting Standards Pension Harmonization Rule AGENCY: Cost Accounting Standards Board, Office of Federal Procurement Policy, Office of... Policy (OFPP), Cost Accounting Standards Board (Board), is publishing technical corrections to the final...

  4. State Skill Standards: Photography

    Science.gov (United States)

    Howell, Frederick; Reed, Loretta; Jensen, Capra; Robison, Gary; Taylor, Susan; Pavesich, Christine

    2007-01-01

    The Department of Education has undertaken an ambitious effort to develop statewide skill standards for all content areas in career and technical education. The standards in this document are for photography programs and are designed to clearly state what the student should know and be able to do upon completion of an advanced high-school program.…

  5. Standards and Administration.

    Science.gov (United States)

    Gross, S. P.

    1978-01-01

    Presents a literature review of water quality standards and administration, covering publications of 1976-77. Consideration is given to municipal facilities, National Pollutant Discharge Elimination Systems, regional and international water quality management, and effluent standards. A list of 99 references is also presented. (HM)

  6. How many standards?

    DEFF Research Database (Denmark)

    Maegaard, Marie

    2009-01-01

    Discussions of standardisation and standard languages has a long history in linguistics. Tore Kristiansen has contributed to these discussions in various ways, and in this chapter I will focus on his claim that young Danes operate with two standards, one for the media and one for the school...

  7. Standard Weights and Measures

    Indian Academy of Sciences (India)

    The mass standard, represented by the proto- type kilogram, is the only remaining artifact, but there are promising proposals to replace that in the near future. Ever since humans started living in community settle- ments, day to day activities have required the adoption of a set of standards for weights and measures. For ex-.

  8. Teachers Voices Interpreting Standards

    Directory of Open Access Journals (Sweden)

    Leo C. Rigsby

    2003-11-01

    Full Text Available The State of Virginia has adopted state-mandated testing that aims to raise the standards of performance for children in our schools in a manner that assigns accountability to schools and to teachers. In this paper we argue that the conditions under which the standards were created and the testing implemented undermine the professionalism of teachers. We believe this result has the further consequence of compromising the critical thinking and learning processes of children. We argue this has happened because teachers’ views and experiences have driven neither the setting of standards nor the assessment of their achievement. We use data from essays by teachers in an innovative masters program to compare teachers’ experiences involving the Virginia Standards of Learning with ideal standards for professional development adopted by the National Board for Professional Teaching Standards. We argue that there are serious negative consequences of the failure to include dialogue with K-12 teachers in setting standards and especially in the creation of assessments to measure performances relative to the standards. We believe the most successful, honest, and morally defensible processes must be built on the experience and wisdom of classroom teachers.

  9. Revisiting Professional Teacher Standards

    Science.gov (United States)

    Watson, Amanda

    2016-01-01

    The Australian Society for Music Education's (ASME) involvement in the development of professional standards for music educators was a significant and active research time in the history of the Society. As ASME celebrates its golden jubilee, it is appropriate to revisit that history and consider the future prospects of subject-specific standards.…

  10. Weston Standard battery

    CERN Multimedia

    This is a Weston AOIP standard battery with its calibration certificate (1956). Inside, the glassware forms an "H". Its name comes from the British physicist Edward Weston. A standard is the materialization of a given quantity whose value is known with great accuracy.

  11. A case of standardization?

    DEFF Research Database (Denmark)

    Rod, Morten Hulvej; Høybye, Mette Terp

    2016-01-01

    Guidelines are increasingly used in an effort to standardize and systematize health practices at the local level and to promote evidence-based practice. The implementation of guidelines frequently faces problems, however, and standardization processes may in general have other outcomes than...... the ones envisioned by the makers of standards. In 2012, the Danish National Health Authorities introduced a set of health promotion guidelines that were meant to guide the decision making and priority setting of Denmark's 98 local governments. The guidelines provided recommendations for health promotion...... and standardization. It remains an open question whether or not the guidelines lead to more standardized policies and interventions, but we suggest that the guidelines promote a risk factor-oriented approach as the dominant frame for knowledge, reasoning, decision making and priority setting in health promotion. We...

  12. Evaluating Living Standard Indicators

    Directory of Open Access Journals (Sweden)

    Birčiaková Naďa

    2015-09-01

    Full Text Available This paper deals with the evaluation of selected available indicators of living standards, divided into three groups, namely economic, environmental, and social. We have selected six countries of the European Union for analysis: Bulgaria, the Czech Republic, Hungary, Luxembourg, France, and Great Britain. The aim of this paper is to evaluate indicators measuring living standards and suggest the most important factors which should be included in the final measurement. We have tried to determine what factors influence each indicator and what factors affect living standards. We have chosen regression analysis as our main method. From the study of factors, we can deduce their impact on living standards, and thus the value of indicators of living standards. Indicators with a high degree of reliability include the following factors: size and density of population, health care and spending on education. Emissions of carbon dioxide in the atmosphere also have a certain lower degree of reliability.

  13. Standard dilution analysis.

    Science.gov (United States)

    Jones, Willis B; Donati, George L; Calloway, Clifton P; Jones, Bradley T

    2015-02-17

    Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES.

  14. Operator licensing examiner standards

    International Nuclear Information System (INIS)

    1993-01-01

    The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining licensees and applicants for reactor operator and senior reactor operator licenses at power reactor facilities pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). The Examiner Standards are intended to assist NRC examiners and facility licensees to better understand the initial and requalification examination processes and to ensure the equitable and consistent administration of examinations to all applicants. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator licensing policy changes

  15. Wireless installation standard

    International Nuclear Information System (INIS)

    Lim, Hwang Bin

    2007-12-01

    This is divided six parts which are radio regulation law on securing of radio resource, use of radio resource, protection of radio resource, radio regulation enforcement ordinance with securing, distribution and assignment of radio regulation, radio regulation enforcement regulation on utility of radio resource and technical qualification examination, a wireless installation regulation of technique standard and safety facility standard, radio regulation such as certification regulation of information communicative machines and regulation of radio station on compliance of signal security, radio equipment in radio station, standard frequency station and emergency communication.

  16. SOFG: Standards requirements

    International Nuclear Information System (INIS)

    Gerganov, T.; Grigorov, S.; Kozhukharov, V.; Brashkova, N.

    2005-01-01

    It is well-known that Solid Oxide Fuel Cells will have industrial application in the nearest future. In this context, the problem of SOFC materials and SOFC systems standardization is of high level of priority. In the present study the attention is focused on the methods for physical and chemical characterization of the materials for SOFC components fabrication and about requirements on single SOFC cells tests. The status of the CEN, ISO, ASTM (ANSI, ASSN) and JIS class of standards has been verified. Standards regarding the test methods for physical-chemical characterization of vitreous materials (as sealing SOFC component), ceramic materials (as electrodes and electrolyte components, including alternative materials used) and metallic materials (interconnect components) are subject of overview. It is established that electrical, mechanical, surface and interfacial phenomena, chemical durability and thermal corrosion behaviour are the key areas for standardization of the materials for SOFC components

  17. Scrutinising safety standards

    Energy Technology Data Exchange (ETDEWEB)

    Pietersen, C.M. [Safety Service Center BV (Netherlands)

    2001-01-01

    Until the introduction of the International Electrotechnical Commission's standard IEC 61508, there was no provision for relating risks to people and the environment, to the risks of financial loss. Although IEC 61508 fills most of the gaps in the process industry, there are still some loopholes. Four points covered by the standard are listed. It is expected that the standard will lead to an optimum cost-benefit situation with 'fit-for-purpose' safety and minimum nuisance shutdowns, or process plant disturbances. It should give clear guidance on 'how safe is safe enough.' IEC 61508 can be implemented through various routes. Insurance companies and regulators are starting to require implementation of the new standard. Five points which need to be ascertained for implementation are listed and diagrams illustrate the IEC 61508 safety lifecycle and the risk-reduction requirements.

  18. STELLA Standards Framework.

    Science.gov (United States)

    English in Australia, 2001

    2001-01-01

    Presents a provisional framework for the STELLA (Standards for Teachers of English Language and Literacy in Australia), which identifies broad dimensions of teaching together with groupings of related attributes derived from teachers' narratives. (RS)

  19. Ozone Standard Reference Photometer

    Data.gov (United States)

    Federal Laboratory Consortium — The Standard Reference Photometer (SRP) Program began in the early 1980s as collaboration between NIST and the U.S. Environmental Protection Agency (EPA) to design,...

  20. National Pesticide Standard Repository

    Science.gov (United States)

    EPA's National Pesticide Standards Repository collects and maintains an inventory of analytical “standards” of registered pesticides in the United States, as well as some that are not currently registered for food and product testing and monitoring.

  1. Beyond the standard model

    International Nuclear Information System (INIS)

    Gaillard, M.K.

    1990-04-01

    The unresolved issues of the standard model are reviewed, with emphasis on the gauge hierarchy problem. A possible mechanism for generating a hierarchy in the context of superstring theory is described. 24 refs

  2. Standardization in synthetic biology.

    Science.gov (United States)

    Müller, Kristian M; Arndt, Katja M

    2012-01-01

    Synthetic Biology is founded on the idea that complex biological systems are built most effectively when the task is divided in abstracted layers and all required components are readily available and well-described. This requires interdisciplinary collaboration at several levels and a common understanding of the functioning of each component. Standardization of the physical composition and the description of each part is required as well as a controlled vocabulary to aid design and ensure interoperability. Here, we describe standardization initiatives from several disciplines, which can contribute to Synthetic Biology. We provide examples of the concerted standardization efforts of the BioBricks Foundation comprising the request for comments (RFC) and the Registry of Standardized Biological parts as well as the international Genetically Engineered Machine (iGEM) competition.

  3. AKRO: Standard Prices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard prices are generated for cost recovery programs in the Individual Fishing Quota (IFQ) halibut and sablefish, BSAI Rationalized crab, and Central Gulf of...

  4. Fiber optics standard dictionary

    CERN Document Server

    Weik, Martin H

    1997-01-01

    Fiber Optics Vocabulary Development In 1979, the National Communications System published Technical InfonnationBulle­ tin TB 79-1, Vocabulary for Fiber Optics and Lightwave Communications, written by this author. Based on a draft prepared by this author, the National Communications System published Federal Standard FED-STD-1037, Glossary of Telecommunications Terms, in 1980 with no fiber optics tenns. In 1981, the first edition of this dictionary was published under the title Fiber Optics and Lightwave Communications Standard Dictionary. In 1982, the then National Bureau of Standards, now the National Institute of Standards and Technology, published NBS Handbook 140, Optical Waveguide Communications Glossary, which was also published by the General Services Admin­ istration as PB82-166257 under the same title. Also in 1982, Dynamic Systems, Inc. , Fiberoptic Sensor Technology Handbook, co-authored and edited by published the this author, with an extensive Fiberoptic Sensors Glossary. In 1989, the handbook w...

  5. FDA Recognized Consensus Standards

    Data.gov (United States)

    U.S. Department of Health & Human Services — This database consists of those national and international standards recognized by FDA which manufacturers can declare conformity to and is part of the information...

  6. [Standardization of hospital feeding].

    Science.gov (United States)

    Caracuel García, Ángel Manuel

    2015-05-07

    Normalization can be understood as the establishing measures against repetitive situations through the development, dissemination, and application of technical design documents called standards. In Andalusia there are 45 public hospitals with 14,606 beds, and in which 11,700 full pensions / day are served. The Working Group on Hospital Food Standardization of the Andalusian Society for Clinical Nutrition and Dietetics, started in 2010, working on the certification of suppliers, product specifications, and meals technical card. - Develop a specific tool to help improving food safety through the certification of their suppliers. - Develop a standardized technical specifications of foodstuffs necessary for the development of menus established codes diets Andalusian hospitals document. - Develop a catalog of data sheets plates of hospital meals, to homogenize menus, respecting local and unifying criteria for qualitative and quantitative ingredients. - Providing documentation and studying of several public hospitals in Andalusia: • Product specifications and certification of suppliers. • International standards certification and distribution companies. • Legislation. • Data sheets for the menu items. • Specifications of different product procurement procedures. - Development of the draft standard HOSPIFOOD®, and approval of the version “0.0”. - Training course for auditors to this standard. - Development of a raw materials catalog as technical cards. - Meals Technical cards review and election of the ones which will be part of the document. After nearly three years of work, we have achieved the following products: - Standardized database of technical specifications for the production of food dietary codes for: fish, seafood, meat and meat products, meats and pates, ready meals, bread and pastries, preserves, milk and dairy products, oils, cereals, legumes , vegetables, fruits, fresh and frozen vegetables, condiments and spices. - Standardized database of

  7. The Gold Standard Programme

    DEFF Research Database (Denmark)

    Neumann, Tim; Rasmussen, Mette; Ghith, Nermin

    2013-01-01

    To evaluate the real-life effect of an evidence-based Gold Standard Programme (GSP) for smoking cessation interventions in disadvantaged patients and to identify modifiable factors that consistently produce the highest abstinence rates.......To evaluate the real-life effect of an evidence-based Gold Standard Programme (GSP) for smoking cessation interventions in disadvantaged patients and to identify modifiable factors that consistently produce the highest abstinence rates....

  8. Standard software for CAMAC

    International Nuclear Information System (INIS)

    Lenkszus, F.R.

    1978-01-01

    The NIM Committee (National Instrumentation Methods Committee) of the U.S. Department of Energy and the ESONE Committee of European Laboratories have jointly specified standard software for use with CAMAC. Three general approaches were followed: the definition of a language called IML for use in CAMAC systems, the definition of a standard set of subroutine calls, and real-time extensions to the BASIC language. This paper summarizes the results of these efforts. 1 table

  9. Beyond the standard model

    International Nuclear Information System (INIS)

    Pleitez, V.

    1994-01-01

    The search for physics laws beyond the standard model is discussed in a general way, and also some topics on supersymmetry theories. An approach is made on recent possibilities rise in the leptonic sector. Finally, models with SU(3) c X SU(2) L X U(1) Y symmetry are considered as alternatives for the extensions of the elementary particles standard model. 36 refs., 1 fig., 4 tabs

  10. Technical standards in nuclear area

    International Nuclear Information System (INIS)

    Grimberg, M.

    1978-01-01

    The technical standardization in nuclear area is discussed. Also, the competence of CNEN in standardization pursuit is analysed. Moreover, the process of working up of technical standards is explained; in addition, some kinds of technical standards are discussed. (author) [pt

  11. ISO radiation sterilization standards

    International Nuclear Information System (INIS)

    Lambert, Byron J.; Hansen, Joyce M.

    1998-01-01

    This presentation provides an overview of the current status of the ISO radiation sterilization standards. The ISO standards are voluntary standards which detail both the validation and routine control of the sterilization process. ISO 11137 was approved in 1994 and published in 1995. When reviewing the standard you will note that less than 20% of the standard is devoted to requirements and the remainder is guidance on how to comply with the requirements. Future standards developments in radiation sterilization are being focused on providing additional guidance. The guidance that is currently provided in informative annexes of ISO 11137 includes: device/packaging materials, dose setting methods, and dosimeters and dose measurement, currently, there are four Technical Reports being developed to provide additional guidance: 1. AAMI Draft TIR, 'Radiation Sterilization Material Qualification' 2. ISO TR 13409-1996, 'Sterilization of health care products - Radiation sterilization - Substantiation of 25 kGy as a sterilization dose for small or infrequent production batches' 3. ISO Draft TR, 'Sterilization of health care products - Radiation sterilization Selection of a sterilization dose for a single production batch' 4. ISO Draft TR, 'Sterilization of health care products - Radiation sterilization-Product Families, Plans for Sampling and Frequency of Dose Audits'

  12. DOE technical standards list. Department of Energy standards index

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    This document was prepared for use by personnel involved in the selection and use of DOE technical standards and other Government and non-Government standards. This TSL provides listing of current DOE technical standards, non-Government standards that have been adopted by DOE, other Government documents in which DOE has a recorded interest, and canceled DOE technical standards. Information on new DOE technical standards projects, technical standards released for coordination, recently published DOE technical standards, and activities of non-Government standards bodies that may be of interest to DOE is published monthly in Standards Actions.

  13. DOE technical standards list: Department of Energy standards index

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    This Department of Energy (DOE) technical standards list (TSL) has been prepared by the Office of Nuclear Safety Policy and Standards (EH-31) on the basis of currently available technical information. Periodic updates of this TSL will be issued as additional information is received on standardization documents being issued, adopted, or canceled by DOE. This document was prepared for use by personnel involved in the selection and use of DOE technical standards and other Government and non-Government standards. This TSL provides listings of current DOE technical standards, non-Government standards that have been adopted by DOE, other standards-related documents in which DOE has a recorded interest, and canceled DOE technical standards. Information on new DOE technical standards projects, technical standards released for coordination, recently published DOE technical standards, and activities of non-Government standards bodies that may be of interest to DOE is published monthly in Standards Actions.

  14. IAEA Safety Standards

    International Nuclear Information System (INIS)

    2016-09-01

    The IAEA Safety Standards Series comprises publications of a regulatory nature covering nuclear safety, radiation protection, radioactive waste management, the transport of radioactive material, the safety of nuclear fuel cycle facilities and management systems. These publications are issued under the terms of Article III of the IAEA’s Statute, which authorizes the IAEA to establish “standards of safety for protection of health and minimization of danger to life and property”. Safety standards are categorized into: • Safety Fundamentals, stating the basic objective, concepts and principles of safety; • Safety Requirements, establishing the requirements that must be fulfilled to ensure safety; and • Safety Guides, recommending measures for complying with these requirements for safety. For numbering purposes, the IAEA Safety Standards Series is subdivided into General Safety Requirements and General Safety Guides (GSR and GSG), which are applicable to all types of facilities and activities, and Specific Safety Requirements and Specific Safety Guides (SSR and SSG), which are for application in particular thematic areas. This booklet lists all current IAEA Safety Standards, including those forthcoming

  15. GISB: Efficiency through standardization

    International Nuclear Information System (INIS)

    White, B.

    1995-01-01

    For those who participated in the numerous day-long development sessions held in the dim, stale basement auditorium of the Department of Energy, the ida that the Gas Industry standards Board (GISB) would be producing standards anytime soon seemed a distant dream. However, the hazy vision of just over a year ago has now become a reality. As summer turns to fall and young gas schedulers throughout this country dream of the gridiron, GISB will have already issued a model electronic-trading partner agreement and 12 standards for capacity-release transactions, as well as three standards for nomination-related transactions. Under the steady hand of Executive directors Rae McQuade and a board of director that looks like a Who's Who of the gas industry, GISB has developed into a organization that will directly influence how gas is purchased, transported, and accounted and paid for in the 21st century. The paper describes the background of the organization, standards that have been released, and issues still to be addressed

  16. Sports eyewear protective standards.

    Science.gov (United States)

    Dain, Stephen J

    2016-01-01

    Eye injuries sustained during sport comprise up to 20 per cent of all injuries to the eye serious enough for medical attention to be sought. The prevalence of eye injuries in sport is not easily assessed due to lack of authoritative participation rates, so most studies report total numbers in a time period. The evidence on the proportion of all ocular injuries that are from sport is reviewed. The relative frequencies in different sports are compared in a qualitative manner and the sports with greater numbers of ocular injuries are detailed. In common with occupational injuries to the eye, most sports eye injuries are considered preventable. The hierarchy of action for occupational risk is detailed and adapted to use in a sports scenario. All the available international, regional and national standards on sports eye protection are detailed and their provisions compared. The major function of the standards is to provide adequate protection against the hazard of the sport concerned. These are detailed and compared as a function of energy transfer. Eye protection must not introduce additional or secondary hazards (for instance, fracturing into sharp fragments on impact) and not introduce features that would deter the wearing of eye protection (for instance, restricting field of view to impede playing the sport). The provisions of the standards intended to limit secondary hazards are detailed and compared. The need for future work in standards writing and the activities of the International Standardization Organization in sports eye protection are detailed. © 2016 Optometry Australia.

  17. Standards and quality

    CERN Document Server

    El-Tawil, Anwar

    2015-01-01

    The book brings together a number of subjects of prime importance for any practicing engineer and, students of engineering. The book explains the concepts and functions of voluntary standards, mandatory technical regulations, conformity assessment (testing and measurement of products), certification, quality and quality management systems as well as other management systems such as environmental, social responsibility and food safety management systems.The book also gives a comprehensive description of the role of metrology systems that underpin conformity assessment. A description is given of typical national systems of standards, quality and metrology and how they relate directly or through regional structures to international systems. The book also covers the relation between standards and trade and explains the context and stipulations of the Technical Barriers to Trade Agreement of the World Trade Organization (WTO).

  18. Operator licensing examiner standards

    International Nuclear Information System (INIS)

    1983-10-01

    The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining and licensing of applicants for NRC operator licenses pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). They are intended to assist NRC examiners and facility licensees to understand the examination process better and to provide for equitable and consistent administration of examinations to all applicants by NRC examiners. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator examination licensing policy changes. As appropriate, these standards will be revised periodically to accommodate comments and reflect new information or experience

  19. Standardization of depression measurement

    DEFF Research Database (Denmark)

    Wahl, Inka; Löwe, Bernd; Bjørner, Jakob

    2014-01-01

    OBJECTIVES: To provide a standardized metric for the assessment of depression severity to enable comparability among results of established depression measures. STUDY DESIGN AND SETTING: A common metric for 11 depression questionnaires was developed applying item response theory (IRT) methods. Data...... of 33,844 adults were used for secondary analysis including routine assessments of 23,817 in- and outpatients with mental and/or medical conditions (46% with depressive disorders) and a general population sample of 10,027 randomly selected participants from three representative German household surveys....... RESULTS: A standardized metric for depression severity was defined by 143 items, and scores were normed to a general population mean of 50 (standard deviation = 10) for easy interpretability. It covers the entire range of depression severity assessed by established instruments. The metric allows...

  20. Conference: STANDARD MODEL @ LHC

    CERN Multimedia

    2012-01-01

    HCØ institute Universitetsparken 5 DK-2100 Copenhagen Ø Denmark Room: Auditorium 2 STANDARD MODEL @ LHC Niels Bohr International Academy and Discovery Center 10-13 April 2012 This four day meeting will bring together both experimental and theoretical aspects of Standard Model phenomenology at the LHC. The very latest results from the LHC experiments will be under discussion. Topics covered will be split into the following categories:     * QCD (Hard,Soft & PDFs)     * Vector Boson production     * Higgs searches     * Top Quark Physics     * Flavour physics

  1. Operator licensing examiner standards

    International Nuclear Information System (INIS)

    1987-05-01

    The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining and licensing of applicants for NRC operator licenses pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). They are intended to assist NRC examiners and facility licensees to understand the examination process better and to provide for equitable and consistent administration of examinations to all applicants by NRC examiners. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator examination licensing policy changes

  2. The Standard Model

    Science.gov (United States)

    Burgess, Cliff; Moore, Guy

    2012-04-01

    List of illustrations; List of tables; Preface; Acknowledgments; Part I. Theoretical Framework: 1. Field theory review; 2. The standard model: general features; 3. Cross sections and lifetimes; Part II. Applications: Leptons: 4. Elementary boson decays; 5. Leptonic weak interactions: decays; 6. Leptonic weak interactions: collisions; 7. Effective Lagrangians; Part III. Applications: Hadrons: 8. Hadrons and QCD; 9. Hadronic interactions; Part IV. Beyond the Standard Model: 10. Neutrino masses; 11. Open questions, proposed solutions; Appendix A. Experimental values for the parameters; Appendix B. Symmetries and group theory review; Appendix C. Lorentz group and the Dirac algebra; Appendix D. ξ-gauge Feynman rules; Appendix E. Metric convention conversion table; Select bibliography; Index.

  3. Standard for metric practice

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This standard gives guidance for application of the modernized metric system in the United States. The International System of Units, developed and maintained by the General Conference on Weights and Measures (abbreviated CGPM from the official French name Conference Generale des Poids et Measures) is intended as a basis for worldwide standardization of measurement units. The name International System of Units and the international abbreviation SI 2 were adopted by the 11th CGPM in 1960. SI is a complete, coherent system that is being universally adopted

  4. Coordinate Standard Measurement Development

    Energy Technology Data Exchange (ETDEWEB)

    Hanshaw, R.A.

    2000-02-18

    A Shelton Precision Interferometer Base, which is used for calibration of coordinate standards, was improved through hardware replacement, software geometry error correction, and reduction of vibration effects. Substantial increases in resolution and reliability, as well as reduction in sampling time, were achieved through hardware replacement; vibration effects were reduced substantially through modification of the machine component dampening and software routines; and the majority of the machine's geometry error was corrected through software geometry error correction. Because of these modifications, the uncertainty of coordinate standards calibrated on this device has been reduced dramatically.

  5. Islam, Standards, and Technoscience

    DEFF Research Database (Denmark)

    Fischer, Johan

    Halal (literally, "permissible" or "lawful") production, trade, and standards have become essential to state-regulated Islam and to companies in contemporary Malaysia and Singapore, giving these two countries a special position in the rapidly expanding global market for halal products: in these n......Halal (literally, "permissible" or "lawful") production, trade, and standards have become essential to state-regulated Islam and to companies in contemporary Malaysia and Singapore, giving these two countries a special position in the rapidly expanding global market for halal products...

  6. Standard Weights and Measures

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 8. Standard Weights and Measures. Vasant Natarajan. General Article Volume 6 Issue 8 August 2001 pp 44-59. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/006/08/0044-0059. Author Affiliations.

  7. International Financial Reporting Standards

    DEFF Research Database (Denmark)

    Pontoppidan, Caroline Aggestam

    2011-01-01

    The advance of International Financial Reporting Standards (IFRS) across the globe has accelerated over the last few years. This is placing increasing demands on educators to respond to these changes by an increased focus on IFRS in the curricula of accounting students. This paper reviews a range...

  8. Beyond the Standard Model

    CERN Document Server

    Csáki, Csaba

    2015-01-01

    We introduce aspects of physics beyond the Standard Model focusing on supersymmetry, extra dimensions, and a composite Higgs as solutions to the Hierarchy problem. Lectures given at the 2013 European School of High Energy Physics, Parádfürdo, Hungary, 5-18 June 2013.

  9. Standardized Curriculum for Cosmetology.

    Science.gov (United States)

    Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

    Standardized curricula are provided for two courses for the secondary vocational education program in Mississippi: cosmetology I and II. The 18 units in cosmetology I are as follows: introduction to cosmetology; Vocational Industrial Clubs of America; the look you like; bacteriology; sterilization and sanitation; hair and disorders; draping,…

  10. Standardization of Sign Languages

    Science.gov (United States)

    Adam, Robert

    2015-01-01

    Over the years attempts have been made to standardize sign languages. This form of language planning has been tackled by a variety of agents, most notably teachers of Deaf students, social workers, government agencies, and occasionally groups of Deaf people themselves. Their efforts have most often involved the development of sign language books…

  11. Islam, Standards, and Technoscience

    DEFF Research Database (Denmark)

    Fischer, Johan

    Halal (literally, "permissible" or "lawful") production, trade, and standards have become essential to state-regulated Islam and to companies in contemporary Malaysia and Singapore, giving these two countries a special position in the rapidly expanding global market for halal products: in these n......Halal (literally, "permissible" or "lawful") production, trade, and standards have become essential to state-regulated Islam and to companies in contemporary Malaysia and Singapore, giving these two countries a special position in the rapidly expanding global market for halal products......, this book provides an exploration of the role of halal production, trade, and standards. Fischer explains how the global markets for halal comprise divergent zones in which Islam, markets, regulatory institutions, and technoscience interact and diverge. Focusing on the "bigger institutional picture......" that frames everyday halal consumption, Fischer provides a multisited ethnography of the overlapping technologies and techniques of production, trade, and standards that together warrant a product as "halal," and thereby help to format the market. Exploring global halal in networks, training, laboratories...

  12. Low Impact Development Standards

    Energy Technology Data Exchange (ETDEWEB)

    Loftin, Samuel R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-02

    The goal of the LID Standards is to provide guidance on the planning, design, construction and maintenance of green infrastructure (GI) features at Los Alamos National Laboratory. The success of LID at LANL is dependent on maintaining a consistent approach to achieve effective application, operation, and maintenance of these storm water control features.

  13. Elevating standards, improving safety.

    Science.gov (United States)

    Clarke, Richard

    2014-08-01

    In our latest 'technical guidance' article, Richard Clarke, sales and marketing director at one of the UK's leading lift and escalator specialists, Schindler, examines some of the key issues surrounding the specification, maintenance, and operation of lifts in hospitals to help ensure the highest standards of safety and reliability.

  14. Beyond the standard model

    International Nuclear Information System (INIS)

    Cuypers, F.

    1997-05-01

    These lecture notes are intended as a pedagogical introduction to several popular extensions of the standard model of strong and electroweak interactions. The topics include the Higgs sector, the left-right symmetric model, grand unification and supersymmetry. Phenomenological consequences and search procedures are emphasized. (author) figs., tabs., 18 refs

  15. Standard hakkab tootma Mercedesele

    Index Scriptorium Estoniae

    2005-01-01

    AS Standard sõlmis ühe maailma suurema autotootjaga DaimlerChrysler AG koostöölepingu, mille kohaselt hakkab ettevõte tootma ning müüma kontori- ja teenindussaalide mööblit kontserni kuuluva Mercedes-Benzi Euroopa diileritele

  16. Mixed RIA standard

    International Nuclear Information System (INIS)

    Talan, P.; Mucha, J.; Krizan, J.

    1986-01-01

    For the radioimmunoassay of digoxin, 3,5,3'-triiodothyronine, 17β-estradiol, progesterone, testosterone and α 1 -fetoprotein a mixed standard was prepared of these substances in a gamma globulin solution at a concentration of 0.8 to 1.4 wt.% in an aqueous buffer at pH within the range of 6 - 9. The standard contains digoxin at a concentration of 10 -4 to 10 nmol/l, 17β-estradiol at 10 -4 to 2 nmol/l, progesteron at 10 -4 to 100 nmol/l, testosterone at 1o -4 to 21 nmol/l, and α 1 -fetoprotein at 10 -4 to 10 nmol/l with at least two of these substances having concentrations higher than 10 -3 nmol/l. Examples are given of the preparation of the mixed standard with different concentrations of the components. The use of the standard has the following advantages: it is labor saving, reduces the risk of failure in the manufacture of RIA kits, eliminates mistakes in the selection of kits for the determination of different substances and allows a more economical use of material. (E.S.)

  17. Beyond the Standard Model

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    The necessity for new physics beyond the Standard Model will be motivated. Theoretical problems will be exposed and possible solutions will be described. The goal is to present the exciting new physics ideas that will be tested in the near future. Supersymmetry, grand unification, extra dimensions and string theory will be presented.

  18. DOE standard: Radiological control

    International Nuclear Information System (INIS)

    1999-07-01

    The Department of Energy (DOE) has developed this Standard to assist line managers in meeting their responsibilities for implementing occupational radiological control programs. DOE has established regulatory requirements for occupational radiation protection in Title 10 of the Code of Federal Regulations, Part 835 (10 CFR 835), ''Occupational Radiation Protection''. Failure to comply with these requirements may lead to appropriate enforcement actions as authorized under the Price Anderson Act Amendments (PAAA). While this Standard does not establish requirements, it does restate, paraphrase, or cite many (but not all) of the requirements of 10 CFR 835 and related documents (e.g., occupational safety and health, hazardous materials transportation, and environmental protection standards). Because of the wide range of activities undertaken by DOE and the varying requirements affecting these activities, DOE does not believe that it would be practical or useful to identify and reproduce the entire range of health and safety requirements in this Standard and therefore has not done so. In all cases, DOE cautions the user to review any underlying regulatory and contractual requirements and the primary guidance documents in their original context to ensure that the site program is adequate to ensure continuing compliance with the applicable requirements. To assist its operating entities in achieving and maintaining compliance with the requirements of 10 CFR 835, DOE has established its primary regulatory guidance in the DOE G 441.1 series of Guides. This Standard supplements the DOE G 441.1 series of Guides and serves as a secondary source of guidance for achieving compliance with 10 CFR 835

  19. DOE standard: Radiological control

    Energy Technology Data Exchange (ETDEWEB)

    1999-07-01

    The Department of Energy (DOE) has developed this Standard to assist line managers in meeting their responsibilities for implementing occupational radiological control programs. DOE has established regulatory requirements for occupational radiation protection in Title 10 of the Code of Federal Regulations, Part 835 (10 CFR 835), ``Occupational Radiation Protection``. Failure to comply with these requirements may lead to appropriate enforcement actions as authorized under the Price Anderson Act Amendments (PAAA). While this Standard does not establish requirements, it does restate, paraphrase, or cite many (but not all) of the requirements of 10 CFR 835 and related documents (e.g., occupational safety and health, hazardous materials transportation, and environmental protection standards). Because of the wide range of activities undertaken by DOE and the varying requirements affecting these activities, DOE does not believe that it would be practical or useful to identify and reproduce the entire range of health and safety requirements in this Standard and therefore has not done so. In all cases, DOE cautions the user to review any underlying regulatory and contractual requirements and the primary guidance documents in their original context to ensure that the site program is adequate to ensure continuing compliance with the applicable requirements. To assist its operating entities in achieving and maintaining compliance with the requirements of 10 CFR 835, DOE has established its primary regulatory guidance in the DOE G 441.1 series of Guides. This Standard supplements the DOE G 441.1 series of Guides and serves as a secondary source of guidance for achieving compliance with 10 CFR 835.

  20. Hg(+) Frequency Standards

    Science.gov (United States)

    Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2000-01-01

    In this paper we review the development of Hg(+) microwave frequency standards for use in high reliability and continuous operation applications. In recent work we have demonstrated short-term frequency stability of 3 x 10(exp -14)/nu(sub tau) when a cryogenic oscillator of stability 2-3 x 10(exp 15) was used a the local oscillator. The trapped ion frequency standard employs a Hg-202 discharge lamp to optically pump the trapped Hg(+)-199 clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg(+) ion trap based frequency standard with an extended linear ion trap (LITE) architecture which separates the optical state selection region from the clock resonance region. This separation allows the use of novel trap configurations in the resonance region since no optical pumping is carried out there. A method for measuring the size of an ion cloud inside a linear trap with a 12-rod trap is currently being investigated. At approx. 10(exp -12), the 2nd order Doppler shift for trapped mercury ion frequency standards is one of the largest frequency offsets and its measurement to the 1% level would represent an advance in insuring the very long-term stability of these standards to the 10(exp -14) or better level. Finally, we describe atomic clock comparison experiments that can probe for a time variation of the fine structure constant, alpha = e(exp 2)/2(pi)hc, at the level of 10(exp -20)/year as predicted in some Grand Unified String Theories.

  1. Department of Energy Standards Index

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    This TSL, intended for use in selecting and using DOE technical standards and other Government and non-Government standards, provides listing of current and inactive DOE technical standards, non-Government standards adopted by DOE, other Government documents in which DOE has a recorded interest, and cancelled DOE technical standards.

  2. DOE technical standards list: Department of Energy standards index

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    This technical standards list (TSL) was prepared for use by personnel involved in the selection and use of US DOE technical standards and other government and non-government standards. This TSL provides listings of current DOE technical standards, non-government standards that have been adopted by DOE, other government documents in which DOE has a recorded interest, and cancelled DOE technical standards. Standards are indexed by type in the appendices to this document. Definitions of and general guidance for the use of standards are also provided.

  3. Beyond the Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, M.E.

    1997-05-01

    These lectures constitute a short course in ``Beyond the Standard Model`` for students of experimental particle physics. The author discusses the general ideas which guide the construction of models of physics beyond the Standard model. The central principle, the one which most directly motivates the search for new physics, is the search for the mechanism of the spontaneous symmetry breaking observed in the theory of weak interactions. To illustrate models of weak-interaction symmetry breaking, the author gives a detailed discussion of the idea of supersymmetry and that of new strong interactions at the TeV energy scale. He discusses experiments that will probe the details of these models at future pp and e{sup +}e{sup {minus}} colliders.

  4. Beyond the Standard Model

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1997-05-01

    These lectures constitute a short course in ''Beyond the Standard Model'' for students of experimental particle physics. The author discusses the general ideas which guide the construction of models of physics beyond the Standard model. The central principle, the one which most directly motivates the search for new physics, is the search for the mechanism of the spontaneous symmetry breaking observed in the theory of weak interactions. To illustrate models of weak-interaction symmetry breaking, the author gives a detailed discussion of the idea of supersymmetry and that of new strong interactions at the TeV energy scale. He discusses experiments that will probe the details of these models at future pp and e + e - colliders

  5. Non_standard Wood

    DEFF Research Database (Denmark)

    Tamke, Martin

    . Using parametric design tools and computer controlled production facilities Copenhagens Centre for IT and Architecture undertook a practice based research into performance based non-standard element design and mass customization techniques. In close cooperation with wood construction software......Non-Standard elements in architecture bear the promise of a better more specific performance (Oosterhuis 2003). A new understanding of design evolves, which is focusing on open ended approaches, able to negotiate between shifting requirements and to integrate knowledge on process and material......, but the integration of traditional wood craft techniques. The extensive use of self adjusting, load bearing wood-wood joints contributed to ease in production and assembly of a performance based architecture....

  6. Standardization of Speech Corpus

    Directory of Open Access Journals (Sweden)

    Ai-jun Li

    2007-12-01

    Full Text Available Speech corpus is the basis for analyzing the characteristics of speech signals and developing speech synthesis and recognition systems. In China, almost all speech research and development affiliations are developing their own speech corpora. We have so many different kinds numbers of Chinese speech corpora that it is important to be able to conveniently share these speech corpora to avoid wasting time and money and to make research work more efficient. The primary goal of this research is to find a standard scheme which can make the corpus be established more efficiently and be used or shared more easily. A huge speech corpus on 10 regional accented Chinese, RASC863 (a Regional Accent Speech Corpus funded by National 863 Project will be exemplified to illuminate the standardization of speech corpus production.

  7. Testing the Standard Model

    CERN Document Server

    Riles, K

    1998-01-01

    The Large Electron Project (LEP) accelerator near Geneva, more than any other instrument, has rigorously tested the predictions of the Standard Model of elementary particles. LEP measurements have probed the theory from many different directions and, so far, the Standard Model has prevailed. The rigour of these tests has allowed LEP physicists to determine unequivocally the number of fundamental 'generations' of elementary particles. These tests also allowed physicists to ascertain the mass of the top quark in advance of its discovery. Recent increases in the accelerator's energy allow new measurements to be undertaken, measurements that may uncover directly or indirectly the long-sought Higgs particle, believed to impart mass to all other particles.

  8. Standard Model physics

    CERN Multimedia

    Altarelli, Guido

    1999-01-01

    Introduction structure of gauge theories. The QEDand QCD examples. Chiral theories. The electroweak theory. Spontaneous symmetry breaking. The Higgs mechanism Gauge boson and fermion masses. Yukawa coupling. Charges current couplings. The Cabibo-Kobayashi-Maskawa matrix and CP violation. Neutral current couplings. The Glasow-Iliopoulos-Maiani mechanism. Gauge boson and Higgs coupling. Radiative corrections and loops. Cancellation of the chiral anomaly. Limits on the Higgs comparaison. Problems of the Standard Model. Outlook.

  9. Standard model and beyond

    International Nuclear Information System (INIS)

    Quigg, C.

    1984-09-01

    The SU(3)/sub c/ circle crossSU(2)/sub L/circle crossU(1)/sub Y/ gauge theory of ineractions among quarks and leptons is briefly described, and some recent notable successes of the theory are mentioned. Some shortcomings in our ability to apply the theory are noted, and the incompleteness of the standard model is exhibited. Experimental hints that Nature may be richer in structure than the minimal theory are discussed. 23 references

  10. DOE standard: Firearms safety

    International Nuclear Information System (INIS)

    1996-02-01

    Information in this document is applicable to all DOE facilities, elements, and contractors engaged in work that requires the use of firearms as provided by law or contract. The standard in this document provides principles and practices for implementing a safe and effective firearms safety program for protective forces and for non-security use of firearms. This document describes acceptable interpretations and methods for meeting Order requirements

  11. Determination of standard data

    International Nuclear Information System (INIS)

    Pychlau, P.

    1986-01-01

    The standard data used for diagnostic radiography refer to the filter system, the Bucky grid, the film type, exposure, and film processing method. The same type of reference data is established for fluoroscopic screen devices, with data on the fluoroscopic exposure time and the area exposure product in addition. The measurements are done in compliance with section 29 X-Ray Ordinance and DIN 6868. (DG) [de

  12. Non_standard Wood

    DEFF Research Database (Denmark)

    Tamke, Martin

    . Using parametric design tools and computer controlled production facilities Copenhagens Centre for IT and Architecture undertook a practice based research into performance based non-standard element design and mass customization techniques. In close cooperation with wood construction software......, but the integration of traditional wood craft techniques. The extensive use of self adjusting, load bearing wood-wood joints contributed to ease in production and assembly of a performance based architecture....

  13. DOE standard: Firearms safety

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    Information in this document is applicable to all DOE facilities, elements, and contractors engaged in work that requires the use of firearms as provided by law or contract. The standard in this document provides principles and practices for implementing a safe and effective firearms safety program for protective forces and for non-security use of firearms. This document describes acceptable interpretations and methods for meeting Order requirements.

  14. New standard environmental management

    International Nuclear Information System (INIS)

    Andriola, Luca; Luciani, Roberto

    2006-01-01

    The ISO 14001:2004 standard, like ISO 9001:2000 on quality management, transcends the preventive approach (based on a rigid and more or less adequate process-management model still mainly inspired by traditional production methods) and introduces in its stead a highly flexible approach applicable to any socio-economic activity. It is structured by processes rather than system elements, and is based on the quest for efficacy and ongoing improvement [it

  15. Telemetry Standards, Part 1

    Science.gov (United States)

    2015-07-01

    protocol RCC Range Commanders Council RFC Request For Comment RIU remote interface unit RMM removable memory module RS Recommended Standard RSCF...followed by hex characters Comments COMMENTS G\\COM Allowed when: Always Provide the additional information requested or any other information desired...if applicable. Range: 6 characters Comments COMMENTS M-x\\COM Allowed when: When M\\ID is specified Provide the additional information requested or

  16. Natural matrix standards

    International Nuclear Information System (INIS)

    Bowen, V.T.

    1976-01-01

    Environmental radiochemistry needs, for use in analytical intercomparision and as standard reference materials, very large homogeneous samples of a variety of matrices, each naturally contaminated by a variety of longer-lived radionuclides, at several different ranges of concentrations. The reasons for this need are discussed, and the minimum assortment of matrices of radionuclides, and of concentrations is established. Sources of suitable materials are suggested, and the international approach to meeting this need is emphasized

  17. Standard biological parts knowledgebase.

    Science.gov (United States)

    Galdzicki, Michal; Rodriguez, Cesar; Chandran, Deepak; Sauro, Herbert M; Gennari, John H

    2011-02-24

    We have created the Knowledgebase of Standard Biological Parts (SBPkb) as a publically accessible Semantic Web resource for synthetic biology (sbolstandard.org). The SBPkb allows researchers to query and retrieve standard biological parts for research and use in synthetic biology. Its initial version includes all of the information about parts stored in the Registry of Standard Biological Parts (partsregistry.org). SBPkb transforms this information so that it is computable, using our semantic framework for synthetic biology parts. This framework, known as SBOL-semantic, was built as part of the Synthetic Biology Open Language (SBOL), a project of the Synthetic Biology Data Exchange Group. SBOL-semantic represents commonly used synthetic biology entities, and its purpose is to improve the distribution and exchange of descriptions of biological parts. In this paper, we describe the data, our methods for transformation to SBPkb, and finally, we demonstrate the value of our knowledgebase with a set of sample queries. We use RDF technology and SPARQL queries to retrieve candidate "promoter" parts that are known to be both negatively and positively regulated. This method provides new web based data access to perform searches for parts that are not currently possible.

  18. Energy labels and standards

    International Nuclear Information System (INIS)

    Newman, J.

    2000-01-01

    Improving energy efficiency at the end-use level is increasingly important as Climate Change commitments force policy makers to look for areas where greenhouse gas emissions reduction can be achieved rapidly. Indeed, although much improvement has been mode over the past 25 years, significant potential for improving energy efficiency still exists. Labelling and minimum efficiency standards for appliances and equipment have proven to be one of the most promising policy instruments. Used for many years in some IEA Member countries, they delivered tangible results. They are among the cheapest and least intrusive of policies. Policy makers cannot afford to neglect them. This book examines current and post experiences of countries using labels and standards to improve energy end-use efficiency. It identifies successful policy approaches, focusing on what works best. It also provides insight into the opportunities ahead, including the widespread use of computer chips in appliances, cars and equipment. This book should be of great help not only to administrations planning to introduce labelling schemes, but also to those in the process of strengthening their current programmes. Policy makers in developing countries will also find here all necessary justification for implementing labelling and standards in their economy. 74 refs

  19. Operator licensing examiner standards

    International Nuclear Information System (INIS)

    1994-06-01

    The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining licensees and applicants for reactor operator and senior reactor operator licenses at power reactor facilities pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). The Examiner Standards are intended to assist NRC examiners and facility licensees to better understand the initial and requalification examination processes and to ensure the equitable and consistent administration of examinations to all applicants. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator licensing policy changes. Revision 7 was published in January 1993 and became effective in August 1993. Supplement 1 is being issued primarily to implement administrative changes to the requalification examination program resulting from the amendment to 10 CFR 55 that eliminated the requirement for every licensed operator to pass an NRC-conducted requalification examination as a condition for license renewal. The supplement does not substantially alter either the initial or requalification examination processes and will become effective 30 days after its publication is noticed in the Federal Register. The corporate notification letters issued after the effective date will provide facility licensees with at least 90 days notice that the examinations will be administered in accordance with the revised procedures

  20. Implementing PAT with Standards

    Science.gov (United States)

    Chandramohan, Laakshmana Sabari; Doolla, Suryanarayana; Khaparde, S. A.

    2016-02-01

    Perform Achieve Trade (PAT) is a market-based incentive mechanism to promote energy efficiency. The purpose of this work is to address the challenges inherent to inconsistent representation of business processes, and interoperability issues in PAT like cap-and-trade mechanisms especially when scaled. Studies by various agencies have highlighted that as the mechanism evolves including more industrial sectors and industries in its ambit, implementation will become more challenging. This paper analyses the major needs of PAT (namely tracking, monitoring, auditing & verifying energy-saving reports, and providing technical support & guidance to stakeholders); and how the aforesaid reasons affect them. Though current technologies can handle these challenges to an extent, standardization activities for implementation have been scanty for PAT and this work attempts to evolve them. The inconsistent modification of business processes, rules, and procedures across stakeholders, and interoperability among heterogeneous systems are addressed. This paper proposes the adoption of specifically two standards into PAT, namely Business Process Model and Notation for maintaining consistency in business process modelling, and Common Information Model (IEC 61970, 61968, 62325 combined) for information exchange. Detailed architecture and organization of these adoptions are reported. The work can be used by PAT implementing agencies, stakeholders, and standardization bodies.

  1. Emission- and product standards

    International Nuclear Information System (INIS)

    Jong, P. de

    1988-01-01

    This report makes part of a series of eight reports which have been drawn up in behalf of the dutch Policy Notition Radiation Standards (BNS). In this report the results are presented of an inventarization of the use of radioactive materials and ionizing-radiation emitting apparates in the Netherlands. Ch. 2 deals with the varous applications of radioactive materials in the Netherlands. Herein also the numbers and the various locations by application, and the amounts and character of the radioactive materials used, come under discussion. Besides, the various waste currents are considered separately. The use of ionizing-radiation emitting apparates is treated in ch. 3. In ch. 4 the differences and agreements of the various applications, concentrating on the emission and product standards to be drawn up, are entered further. Also on the base of these considerations, a number of starting points are formulated with regard to the way in which emission and product standards may be drawn up. Ch. 7 deals with the conclusions and indicates the most important hiates. (H.W.). 25 refs.; 5 figs.; 25 tabs

  2. Standard biological parts knowledgebase.

    Directory of Open Access Journals (Sweden)

    Michal Galdzicki

    2011-02-01

    Full Text Available We have created the Knowledgebase of Standard Biological Parts (SBPkb as a publically accessible Semantic Web resource for synthetic biology (sbolstandard.org. The SBPkb allows researchers to query and retrieve standard biological parts for research and use in synthetic biology. Its initial version includes all of the information about parts stored in the Registry of Standard Biological Parts (partsregistry.org. SBPkb transforms this information so that it is computable, using our semantic framework for synthetic biology parts. This framework, known as SBOL-semantic, was built as part of the Synthetic Biology Open Language (SBOL, a project of the Synthetic Biology Data Exchange Group. SBOL-semantic represents commonly used synthetic biology entities, and its purpose is to improve the distribution and exchange of descriptions of biological parts. In this paper, we describe the data, our methods for transformation to SBPkb, and finally, we demonstrate the value of our knowledgebase with a set of sample queries. We use RDF technology and SPARQL queries to retrieve candidate "promoter" parts that are known to be both negatively and positively regulated. This method provides new web based data access to perform searches for parts that are not currently possible.

  3. ISO 50001 Energy Management Standard

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-12

    This powerful standard from the International Organization for Standardization (ISO) provides an internationally recognized framework for organizations to voluntarily implement an energy management system.

  4. Standardization as Spaces of Diversity

    Directory of Open Access Journals (Sweden)

    Allison Marie Loconto

    2017-08-01

    Full Text Available Standards have become an important object of investigation in social science and STS scholars have called for a more systematic program of research to study standards or standardization (Busch 2011; Timmermans and Epstein 2010. In this considering concepts paper, we engage with their program for a sociology of standards and propose a new way to think about standards and standardization as “spaces of diversity” so as to push our thinking forward about how standards, standardization and innovation processes are linked. We consider standardization as the dynamic interaction in three spaces (standards in the making, standards in action, and standards in circulation where diversity reemerges only to be tentatively reduced or limited through new rounds of standard setting. We illustrate how diversity is an integral part of standardization with the example of the Rainforest Alliance standard for tea production as it circulated from Costa Rica to Kenya, where it was made and put into action and then circulated again to other African, Asian, and Latin American countries. We end with a proposition for future research on standards to address these other spaces of standards as loci of standardization and innovation.

  5. ESDIS Standards Office (ESO): Requirements, Standards and Practices

    Science.gov (United States)

    Mitchell, Andrew E.; Mcinerney, Mark Allen; Enloe, Yonsok K.; Conover, Helen T.; Doyle, Allan

    2016-01-01

    The ESDIS Standards Office assists the ESDIS Project in formulating standards policy for NASA Earth Science Data Systems (ESDS), coordinates standards activities within ESDIS, and provides technical expertise and assistance with standards related tasks within the NASA Earth Science Data System Working Groups (ESDSWG). This poster summarizes information found on the earthdata.nasa.gov site that describes the ESO.

  6. 76 FR 75840 - Revising Standards Referenced in the Acetylene Standard

    Science.gov (United States)

    2011-12-05

    .... OSHA-2011-0183] RIN 1218-AC64 Revising Standards Referenced in the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Department of Labor. ACTION: Notice of proposed... standards developing organization (``SDO standards''). OSHA also is publishing a direct final rule in today...

  7. Consistency Across Standards or Standards in a New Business Model

    Science.gov (United States)

    Russo, Dane M.

    2010-01-01

    Presentation topics include: standards in a changing business model, the new National Space Policy is driving change, a new paradigm for human spaceflight, consistency across standards, the purpose of standards, danger of over-prescriptive standards, a balance is needed (between prescriptive and general standards), enabling versus inhibiting, characteristics of success-oriented standards, characteristics of success-oriented standards, and conclusions. Additional slides include NASA Procedural Requirements 8705.2B identifies human rating standards and requirements, draft health and medical standards for human rating, what's been done, government oversight models, examples of consistency from anthropometry, examples of inconsistency from air quality and appendices of government and non-governmental human factors standards.

  8. Beyond the Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Lykken, Joseph D.; /Fermilab

    2010-05-01

    'BSM physics' is a phrase used in several ways. It can refer to physical phenomena established experimentally but not accommodated by the Standard Model, in particular dark matter and neutrino oscillations (technically also anything that has to do with gravity, since gravity is not part of the Standard Model). 'Beyond the Standard Model' can also refer to possible deeper explanations of phenomena that are accommodated by the Standard Model but only with ad hoc parameterizations, such as Yukawa couplings and the strong CP angle. More generally, BSM can be taken to refer to any possible extension of the Standard Model, whether or not the extension solves any particular set of puzzles left unresolved in the SM. In this general sense one sees reference to the BSM 'theory space' of all possible SM extensions, this being a parameter space of coupling constants for new interactions, new charges or other quantum numbers, and parameters describing possible new degrees of freedom or new symmetries. Despite decades of model-building it seems unlikely that we have mapped out most of, or even the most interesting parts of, this theory space. Indeed we do not even know what is the dimensionality of this parameter space, or what fraction of it is already ruled out by experiment. Since Nature is only implementing at most one point in this BSM theory space (at least in our neighborhood of space and time), it might seem an impossible task to map back from a finite number of experimental discoveries and measurements to a unique BSM explanation. Fortunately for theorists the inevitable limitations of experiments themselves, in terms of resolutions, rates, and energy scales, means that in practice there are only a finite number of BSM model 'equivalence classes' competing at any given time to explain any given set of results. BSM phenomenology is a two-way street: not only do experimental results test or constrain BSM models, they also suggest

  9. Standardization of biodosimetry operations

    International Nuclear Information System (INIS)

    Dainiak, Nicholas

    2016-01-01

    Methods and procedures for generating, interpreting and scoring the frequency of dicentric chromosomes vary among cytogenetic biodosimetry laboratories (CBLs). This variation adds to the already considerable lack of precision inherent in the dicentric chromosome assay (DCA). Although variability in sample collection, cell preparation, equipment and dicentric frequency scoring can never be eliminated with certainty, it can be substantially minimized, resulting in reduced scatter and improved precision. Use of standard operating procedures and technician exchange may help to mitigate variation. Although the development and adoption of international standards (ISO 21243 and ISO 19238) has helped to reduce variation in standard operating procedures (SOPs), all CBLs must maintain process improvement, and those with challenges may require additional assistance. Sources of variation that may not be readily apparent in the SOPs for sample collection and processing include variability in ambient laboratory conditions, media, serum lot and quantity and the use of particular combinations of cytokines. Variability in maintenance and calibration of metafer equipment, and in scoring criteria, reader proficiency and personal factors may need to be addressed. The calibration curve itself is a source of variation that requires control, using the same known-dose samples among CBLs, measurement of central tendency, and generation of common curves with periodic reassessment to detect drifts in dicentric yield. Finally, the dose estimate should be based on common scoring criteria, using of the z-statistic. Although theoretically possible, it is practically impossible to propagate uncertainty over the entire calibration curve due to the many factors contributing to variance. Periodic re-evaluation of the curve is needed by comparison with newly published curves (using statistical analysis of differences) and determining their potential causes. (author)

  10. Status of conversion of NE standards to national consensus standards

    International Nuclear Information System (INIS)

    Jennings, S.D.

    1990-06-01

    One major goal of the Nuclear Standards Program is to convert existing NE standards into national consensus standards (where possible). This means that an NE standard in the same subject area using the national consensus process. This report is a summary of the activities that have evolved to effect conversion of NE standards to national consensus standards, and the status of current conversion activities. In some cases, all requirements in an NE standard will not be incorporated into the published national consensus standard because these requirements may be considered too restrictive or too specific for broader application by the nuclear industry. If these requirements are considered necessary for nuclear reactor program applications, the program standard will be revised and issued as a supplement to the national consensus standard. The supplemental program standard will contain only those necessary requirements not reflected by the national consensus standard. Therefore, while complete conversion of program standards may not always be realized, the standards policy has been fully supported in attempting to make maximum use of the national consensus standard. 1 tab

  11. Quasi standard model physics

    International Nuclear Information System (INIS)

    Peccei, R.D.

    1986-01-01

    Possible small extensions of the standard model are considered, which are motivated by the strong CP problem and by the baryon asymmetry of the Universe. Phenomenological arguments are given which suggest that imposing a PQ symmetry to solve the strong CP problem is only tenable if the scale of the PQ breakdown is much above M W . Furthermore, an attempt is made to connect the scale of the PQ breakdown to that of the breakdown of lepton number. It is argued that in these theories the same intermediate scale may be responsible for the baryon number of the Universe, provided the Kuzmin Rubakov Shaposhnikov (B+L) erasing mechanism is operative. (orig.)

  12. Non-standard antennas

    CERN Document Server

    Le Chevalier, Francois; Staraj, Robert

    2013-01-01

    This book aims at describing the wide variety of new technologies and concepts of non-standard antenna systems - reconfigurable, integrated, terahertz, deformable, ultra-wideband, using metamaterials, or MEMS,  etc, and how they open the way to a wide range of applications, from personal security and communications to multifunction radars and towed sonars, or satellite navigation systems, with space-time diversity on transmit and receive. A reference book for designers  in this lively scientific community linking antenna experts and signal processing engineers.

  13. Hazard Communication Standard

    International Nuclear Information System (INIS)

    Sichak, S.

    1991-01-01

    The current rate of technological advances has brought with it an overwhelming increase in the usage of chemicals in the workplace and in the home. Coupled to this increase has been a heightened awareness in the potential for acute and chronic injuries attributable to chemical insults. The Hazard Communication Standard has been introduced with the desired goal of reducing workplace exposures to hazardous substances and thereby achieving a corresponding reduction in adverse health effects. It was created and proclaimed by the US Department of Labor and regulated by the Occupational Safety and Health Administration. 1 tab

  14. Standard-model bundles

    CERN Document Server

    Donagi, Ron; Pantev, Tony; Waldram, Dan; Donagi, Ron; Ovrut, Burt; Pantev, Tony; Waldram, Dan

    2002-01-01

    We describe a family of genus one fibered Calabi-Yau threefolds with fundamental group ${\\mathbb Z}/2$. On each Calabi-Yau $Z$ in the family we exhibit a positive dimensional family of Mumford stable bundles whose symmetry group is the Standard Model group $SU(3)\\times SU(2)\\times U(1)$ and which have $c_{3} = 6$. We also show that for each bundle $V$ in our family, $c_{2}(Z) - c_{2}(V)$ is the class of an effective curve on $Z$. These conditions ensure that $Z$ and $V$ can be used for a phenomenologically relevant compactification of Heterotic M-theory.

  15. Primary length standard adjustment

    Science.gov (United States)

    Ševčík, Robert; Guttenová, Jana

    2007-04-01

    This paper deals with problems and techniques connected with primary length standard adjusting, which includes disassembling of the device and by use of the secondary laser with collimated beam and diffraction laws successively reassembling of the laser. In the reassembling process the device was enhanced with substituting the thermal grease cooling of cold finger by copper socket cooler. This improved external cooling system enables more effective cooling of molecular iodine in the cell, which allows better pressure stability of iodine vapor and easier readjustment of the system.

  16. Math: Basic Skills Content Standards

    Science.gov (United States)

    CASAS - Comprehensive Adult Student Assessment Systems (NJ1), 2008

    2008-01-01

    This document presents content standards tables for math. [CASAS content standards tables are designed for educators at national, state and local levels to inform the alignment of content standards, instruction and assessment. The Content Standards along with the CASAS Competencies form the basis of the CASAS integrated assessment and curriculum…

  17. Repeated Interaction in Standard Setting

    NARCIS (Netherlands)

    Larouche, Pierre; Schütt, Florian

    2016-01-01

    As part of the standard-setting process, certain patents become essential. This may allow the owners of these standard-essential patents to hold up implementers of the standard, who can no longer turn to substitute technologies. However, many real-world standards evolve over time, with several

  18. European standards for composite construction

    NARCIS (Netherlands)

    Stark, J.W.B.

    2000-01-01

    The European Standards Organisation (CEN) has planned to develop a complete set of harmonized European building standards. This set includes standards for composite steel and concrete buildings and bridges. The Eurocodes, being the design standards, form part of this total system of European

  19. Emergency Management Standards and Schools

    Science.gov (United States)

    National Clearinghouse for Educational Facilities, 2009

    2009-01-01

    This publication discusses emergency management standards for school use and lists standards recommended by FEMA's National Incident Management System (NIMS). Schools are encouraged to review these standards carefully and to adopt, where applicable, those that meet their needs. The lists of standards, resources, and references contained herein…

  20. XML Diagnostics Description Standard

    International Nuclear Information System (INIS)

    Neto, A.; Fernandes, H.; Varandas, C.; Lister, J.; Yonekawa, I.

    2006-01-01

    A standard for the self-description of fusion plasma diagnostics will be presented, based on the Extensible Markup Language (XML). The motivation is to maintain and organise the information on all the components of a laboratory experiment, from the hardware to the access security, to save time and money when problems arises. Since there is no existing standard to organise this kind of information, every Association stores and organises each experiment in different ways. This can lead to severe problems when the organisation schema is poorly documented or written in national languages. The exchange of scientists, researchers and engineers between laboratories is a common practice nowadays. Sometimes they have to install new diagnostics or to update existing ones and frequently they lose a great deal of time trying to understand the currently installed system. The most common problems are: no documentation available; the person who understands it has left; documentation written in the national language. Standardisation is the key to solving all the problems mentioned. From the commercial information on the diagnostic (component supplier; component price) to the hardware description (component specifications; drawings) to the operation of the equipment (finite state machines) through change control (who changed what and when) and internationalisation (information at least in the native language and in English), a common XML schema will be proposed. This paper will also discuss an extension of these ideas to the self-description of ITER plant systems, since the problems will be identical. (author)