WorldWideScience

Sample records for vlf phase difference

  1. Determining the VLF/ULF source height using phase measurements

    Science.gov (United States)

    Ryabov, A.; Kotik, D. S.

    2012-12-01

    Generation of ULF/VLF waves in the ionosphere using powerful RF facilities has been studied for the last 40 years, both theoretically and experimentally. During this time, it was proposed several mechanisms for explaining the experimental results: modulation of ionospheric currents based on thermal nonlinearity, ponderomotive mechanisms for generation both VLF and ULF signals, cubic nonlinearity, etc. According mentioned above mechanisms the VLF/ULF signal source could be located in the lower or upper ionosphere. The group velocity of signal propagation in the ionosphere is significantly smaller than speed of light. As a result the appreciable time delay of the received signals will occur at the earth surface. This time delay could be determine by measuring the phase difference between received and reference signals, which are GPS synchronized. The experiment on determining the time delay of ULF signal propagation from the ionospheric source was carried out at SURA facility in 2012 and the results are presented in this paper. The comparison with numerical simulation of the time delay using the adjusted IRI model and ionosonde data shows well agreement with the experimental observations. The work was supported by RFBR grant 11-02-00419-a and RF Ministry of education and science by state contract 16.518.11.7066.

  2. Electron and VLF travel time differences for wave-particle interactions at L=4: Pt. 2

    International Nuclear Information System (INIS)

    Rash, J.P.S.; Scourfield, M.W.J.; Dougherty, M.K.

    1984-01-01

    The cyclotron resonance or gyroresonance interaction has been widely invoked as a generation mechanism for discrete VLF emissions and plasmaspheric hiss. This interaction involves electrons and VLF waves travelling in opposite directions along a geomagnetic field line. We examine, for an interaction region in the equatorial plane at L=4, the energy of the resonant electrons as a function of VLF wave frequency and ambient equatorial electron density. Then for two different spatial configurations of the interaction and two standard plasma distribution models we examine the difference in travel times to a ground-based observer in the Southern hemisphere for the electrons and waves taking part in the interaction. This difference in travel times is shown as a function of VLF wave frequency and equatorial electron density. The results, and their significance for observations of auroral electrons and VLF at Sanae, Antarctica, are discussed and compared with similar results for the Cerenkov interaction discussed in an earlier paper

  3. SEX DIFFERENCES OF VLF100 AND VLF50 SPECTRUM OF HEART RATE VARIABILITY IN HEALTHY INDIVIDUALS OF YOUNG AGE AND OLDER SUBJECTS WITH VASCULAR PATHOLOGY IN TERMS OF SEVEN-TEST, HYPERVENTILATION AND ORTHOSTASIS

    Directory of Open Access Journals (Sweden)

    Арнольд Наумович Флейшман

    2017-10-01

    Conclusion. The results of sex differences of the new VLF100 and VLF50 indicators and their interconnection with LF and HF were essential to the study of autonomic provision in the body, characterizing central mechanisms of regulation.

  4. Daytime tropical D region parameters from short path VLF phase and amplitude

    Science.gov (United States)

    Thomson, Neil R.

    2010-09-01

    Observed phases and amplitudes of VLF radio signals, propagating on a short (˜300-km) path, are used to find improved parameters for the lowest edge of the (D region of the) Earth's ionosphere. The phases, relative to GPS 1-s pulses, and the amplitudes were measured both near (˜100 km from) the transmitter, where the direct ground wave is very dominant, and at distances of ˜300 km near where the ionospherically reflected waves form a (modal) minimum with the (direct) ground wave. The signals came from the 19.8 kHz, 1 MW transmitter, NWC, on the North West Cape of Australia, propagating ˜300 km ENE, mainly over the sea, to the vicinity of Karratha/Dampier on the N.W. coast of Australia. The bottom edge of the mid-day tropical/equatorial ionosphere was thus found to be well-modeled by H‧ = 70.5 ± 0.5 km and β = 0.47 ± 0.03 km-1 where H‧ and β are the traditional height and sharpness parameters as used by Wait and by the U.S. Navy in their Earth-ionosphere VLF radio waveguide programs. U.S. Navy modal waveguide code calculations are also compared with those from the wave hop code of Berry and Herman (1971). At least for the vertical electric fields on the path studied here, the resulting phase and amplitude differences (between the ˜100-km and ˜300-km sites) agree very well after just a small adjustment of ˜0.2 km in H‧ between the two codes. Such short paths also allow more localization than the usual long paths; here this localization is to low latitudes.

  5. Quantitative relationship between VLF phase deviations and 1-8 A solar X-ray fluxes during solar flares

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, Y; Murata, H; Sato, T [Hyogo Coll. Of Medicine (Japan). Dept. of Physics

    1977-07-01

    An attempt is made to investigate the quantitative relationship between VLF phase deviations in SPA (sudden phase anomalies) events and associated solar X-ray fluxes in the 1 to 8 A band during solar flares. The phase deviations (..delta..phi) of the 18.6 kHz VLF wave transmitted from NLK, USA are used in this analysis which were recorded at Nishinomiya, Japan during the period June 1974 to May 1975. The solar X-ray fluxes (F/sub 0/) in the 1 to 8 A band are estimated from fsub(min) variations using the empirical expression given by Sato (J.Geomag.Geoelectr.;27: 95(1975)), because no observed data were available on the 1 to 8 a X-ray fluxes during the period of the VLF observation. The result shows that the normalized phase variation, ..delta..phi/coschisub(min), where chisub(min) represents the minimum solar zenith angle on the VLF propagation path, increases with increasing logF/sub 0/. A theoretical explanation for this is presented assuming that enhanced ionizations produced in the lower ionosphere by a monochromatic solar X-ray emission are responsible for the VLF phase deviations. Also it is found that a threshold X-ray flux to produce a detectable SPA effect is approximately 1.5 x 10/sup -3/ cm/sup -2/ sec/sup -1/ in the 1 to 8 a band.

  6. Controlled VLF phase reversal experiment in the magnetosphere

    International Nuclear Information System (INIS)

    Koons, H.C.; Dazey, M.H.; Dowden, R.L.; Amon, L.E.S.

    1976-01-01

    During the 1973 operations of the transportable very low frequency transmitter near Anchorage, Alaska (Lapprox.4), an experiment was performed to determine the effect of controlled phase change of the transmitted wave on the magnetospherically propagated signal received in the conjugate region. At periodic intervals the phase of the driving voltage was changed (essentially instantaneously) by 180degree. The amplitude of the 6.6-kHz signal detected in the conjugate region went to zero and recovered with a characteristic time constant of 33 ms. This is 10 times longer than the antenna current response time and is in fact comparable with characteristic electron interaction times with whistler mode waves. Between the times at which the phase reversals occurred the received signal was amplitude modulated. The period of the modulation was approx.26 ms. An upper side band was present in the spectrum while these pulsations were occurring. These characteristic times are in general agreement with theoretical predictions of bandwidths, growth rates, and particle-trapping frequencies for whistler instabilities in the magnetosphere. Data obtained from the controlled transmissions and from lightning-generated whistlers propagating in the same duct were combined to determine the plasma and wave parameters at the geomagnetic equator. Of particular interest is the level at which the magnetic field of the wave saturated. During the time period for which the data were analyzed this was found to be 3.5 pT (mγ)

  7. Energetic electron precipitation and VLF phase disturbances at middle latitudes following the magnetic storm of December 6, 1971

    International Nuclear Information System (INIS)

    Larsen, T.R.; Potemra, T.A.; Imhof, W.L.; Reagan, J.B.

    1977-01-01

    Enhanced fluxes of electrons precipitating over middle latitudes (L approx. 3--4) were detected by the polar-orbiting satellite 1971-089A following a period of magnetic activity starting on December 16, 1971. The electron fluxes measured in 256 differential channels between 130 and 2800 keV have been coordinated with phase observations of VLF radio waves propagating in the earth-ionosphere waveguide. The VLF paths in question, NLK (near Seattle, Washington) and GBR (at Rugby, England) to APL (near Washington, D. C.), cover approx. =120 0 in longitude and range from L approx. 2.5 to L approx. 4.0 in invariant latitude. These paths showed marked daytime and nighttime phase advances from 1650 UT on December 17 (in excess of 10 μs during maximum disturbance). The phase values did not return to prestorm levels before December 22--23. The unusual presence of these daytime VLF disturbances is offered as evidence for the widespread precipitation at low L shell vales of nearly relativistic electrons (E/sub e/> approx.200 keV) which would be required to penetrate below approx.70-km altitude to affect the daytime VLF transmissions. Wave guide mode calculations using D region electron density profiles deduced from the satellite particle data predict phase advances which agree reasonably well with the observed values. It is concluded that the observed long-lived VLF phase disturbances can be explained by excess D region ionization caused by energetic electrons precipitating from the earth's radiation belt following their injection deep into the magnetosphere during the magnetic storm

  8. Quantitative study of substorm-associated VLF phase anomalies and precipitating energetic electrons on November 13, 1979

    International Nuclear Information System (INIS)

    Kikuchi, T.; Evans, D.S.

    1983-01-01

    The phase anomalies associated with substorms are observed on VLF signals propagating on transauroral paths (transmitters at OMEGA-ALDRA (13.6 kHz), GBR (16.0 kHz), and OMEGA--NORTH DAKOTA (13.6 kHz)) which were continually received at Inubo, Japan, during the events on November 13, 1979. Detailed comparisons are made between these phase anomalies and geomagnetic bays, and quantitative relations are obtained with precipitating energetic electrons (E>30, E>100, and E>300 keV) detected on board the TIROS-N and NOAA 6 satellites. It is concluded that two types of VLF phase anomalies exist which, in turn, are associated with two phases in the history of energetic electron precipitation into the atmosphere. The first type of phase anomaly is associated with direct injection of energetic electrons into the outer magnetosphere and atmosphere which, in turn, is completely correlated in time with development of the auroral electrojet current system. The second type arises from energetic electrons which subsequently precipitate from a trapped electron population and has a delayed onset and prolonged duration. An excellent quantitative correlation is obtained between the logarithm of the electron flux and the magnitude of the phase anomaly on the OMEGA-ALDRA signal. From the local time characteristics of this quantitative relation it is deduced that the electrons with E>300 keV are the main source of D region ionization responsible for the VLF phase anomaly

  9. Modeling solar flare induced lower ionosphere changes using VLF/LF transmitter amplitude and phase observations at a midlatitude site

    Science.gov (United States)

    Schmitter, E. D.

    2013-04-01

    Remote sensing of the ionosphere bottom using long wave radio signal propagation is a still going strong and inexpensive method for continuous monitoring purposes. We present a propagation model describing the time development of solar flare effects. Based on monitored amplitude and phase data from VLF/LF transmitters gained at a mid-latitude site during the currently increasing solar cycle no. 24 a parameterized electron density profile is calculated as a function of time and fed into propagation calculations using the LWPC (Long Wave Propagation Capability). The model allows to include lower ionosphere recombination and attachment coefficients, as well as to identify the relevant forcing X-ray wavelength band, and is intended to be a small step forward to a better understanding of the solar-lower ionosphere interaction mechanisms within a consistent framework.

  10. Disturbance phenomena in VLF standard radio wave observation

    International Nuclear Information System (INIS)

    Muraoka, Yoshikazu

    1977-01-01

    Storm aftereffect, i.e. the phase disturbance after initiation of a magnetic storm has been revealed in the observation of VLF standard radio waves. In VLF long distance propagation at middle latitudes (L - 3), the phase disturbance for several days after the initiation of a magnetic storm is due to electron fall from the radiation belt. This has been confirmed by the comparison with electron flux detected by an artificial satellite. The correlations between VLF phase disturbance and magnetism activity or ionosphere absorption are described. The relation between winter anomaly and phase disturbance is also discussed. (Mori, K.)

  11. Study of the effect of solar flares on VLF signals during D-layer preparation or disappearance time

    Science.gov (United States)

    Ray, Suman; Chakrabarti, Sandip Kumar; Palit, Sourav

    2016-07-01

    "Very Low Frequency" (VLF) is one of the bands of the Radio waves having frequency 3-30 KHz, which propagates through the Earth-ionosphere wave-guide. In relation to propagation of radio waves through ionosphere, low mass and high mobility cause electrons to play a vital role. Electrons are not distributed uniformly in the ionosphere and depending on this factor, ionosphere has different layers namely D, E and F. Different ionospheric layers generally exist during day and night time. During day-time when the main source of the ionization of the ionosphere is Sun, the lower most layer of ionosphere is D-layer. But during the night-time when Sun is absent and cosmic ray is the main source of the ionization of the ionosphere, this D-layer disappears and E-layer becomes the lower most region of the ionosphere. Normally, patterns of VLF signal depend on regular solar flux variations. However, during solar flares extra energetic particles are released from Sun, which makes the changes in the ionization of the ionosphere and these changes can perturb VLF signal amplitude. Usually if a solar flare occurs during any time of day, it only affects the amplitude and phase of the VLF signals. But in the present work, we found the if the flare occurs during D-layer preparation / disappearance time, then it will not only affect to amplitude and phase of the VLF signals but also to terminator times of VLF signals. We have observed that the sun set terminator time of the VLF signals shifted towards night time due to the effect of a M-class solar flare which occurred during the D-layer disappearance time. The shift is so high that it crossed 5σ level. We are now trying to a make model using the ion-chemistry and LWPC code to explain this observed effect.

  12. VLF group delay of lightning-induced electron precipitation echoes from measurement of phase and amplitude perturbations at two frequencies

    International Nuclear Information System (INIS)

    Adams, C.D.D.; Dowden, R.L.

    1990-01-01

    Measurement of phase and amplitude perturbations (trimpis) of the NWC signal at Dunedin at both the NWC frequencies, 22,250 Hz and 22,350 Hz, enables measurement of the received phase of the echo signal (phasor difference of the perturbed and unperturbed signals) at each frequency and so the rate of decrease of phase with frequency. This, of course, is the group delay. The 100-Hz difference implies that measurement of echo group delays of up to 5 ms could be made without ambiguity, though other factors limit this to about 2.5 ms. Some 38 difference trimpis during May and June 1988 showed echo delays up to 2 ms corresponding to reflection from points displaced more than 1,000 km from the NWC-Dunedin great circle path. The echo amplitudes observed at such large displacements are much greater than expected from smooth circular depressions of the ionosphere modifying the waveguide phase velocity and so imply sharper discontinuities in the waveguide

  13. Investigations of equatorial ionosphere nighttime mode conversion at VLF

    Science.gov (United States)

    Hildebrand, Verne

    1993-05-01

    VLF Radiowave propagation provides one of the few viable tools for exploring the properties of the lower D-region ionosphere. Conversely, VLF communications coverage analysis and prediction is directly dependent on the quality of models for the D-region ionosphere. The VLF Omega navigation signals are an excellent and under-utilized resource for conducting D-region research in direct support of VLF communications. Stations are well placed for investigating polar, mid latitude, and equatorial phenomena. Much can be learned by fully utilizing the very stable signals radiated at five frequencies, available from each of the eight transmitters, and taking full advantage of modal structure. While the Omega signals, 10.2 to 13.6 kHz, are well below the VLF communications band, we contend that much of the knowledge gained on D-region characteristics can be directly applied at the higher frequencies. The opportunity offered by Omega needs to be exploited. With the Global Positioning System (GPS) coming onboard as the prime means for global navigation, pressure is mounting to phase out Omega. In this paper we describe how we are using Omega along with computer codes of full wave VLF propagation, provided to us by the U.S. Naval Ocean Systems Center (NOSC), for ionosphere research and by example illustrate the potential for other investigations.

  14. VLF waves in the foreshock

    Science.gov (United States)

    Strangeway, R. J.; Crawford, G. K.

    1995-01-01

    Plasma waves observed in the VLF range upstream of planetary bow shocks not only modify the particle distributions, but also provide important information about the acceleration processes that occur at the bow shock. Electron plasma oscillations observed near the tangent field line in the electron foreshock are generated by electrons reflected at the bow shock through a process that has been referred to as Fast Fermi acceleration. Fast Fermi acceleration is the same as shock-drift acceleration, which is one of the mechanisms by which ions are energized at the shock. We have generated maps of the VLF emissions upstream of the Venus bow shock, using these maps to infer properties of the shock energization processes. We find that the plasma oscillations extend along the field line up to a distance that appears to be controlled by the shock scale size, implying that shock curvature restricsts the flux and energy of reflected electrons. We also find that the ion acoustic waves are observed in the ion foreshock, but at Venus these emissions are not detected near the ULF forshock boundary. Through analogy with terrestrial ion observations, this implies that the ion acoustic waves are not generated by ion beams, but are instead generated by diffuse ion distributions found deep within the ion foreshock. However, since the shock is much smaller at Venus, and there is no magnetosphere, we might expect ion distributions within the ion foreshock to be different than at the Earth. Mapping studies of the terrestrial foreshock similar to those carried out at Venus appear to be necessary to determine if the inferences drawn from Venus data are applicable to other foreshocks.

  15. Beating HF waves to generate VLF waves in the ionosphere

    Science.gov (United States)

    Kuo, Spencer; Snyder, Arnold; Kossey, Paul; Chang, Chia-Lie; Labenski, John

    2012-03-01

    Beat-wave generation of very low frequency (VLF) waves by two HF heaters in the ionosphere is formulated theoretically and demonstrated experimentally. The heater-induced differential thermal pressure force and ponderomotive force, which dominate separately in the D and F regions of the ionosphere, drive an electron current for the VLF emission. A comparison, applying appropriate ionospheric parameters shows that the ponderomotive force dominates in beat-wave generation of VLF waves. Three experiments, one in the nighttime in the absence of D and E layers and two in the daytime in the presence of D and E layers, were performed. X mode HF heaters of slightly different frequencies were transmitted at CW full power. VLF waves at 10 frequencies ranging from 3.5 to 21.5 kHz were generated. The frequency dependencies of the daytime and nighttime radiation intensities are quite similar, but the nighttime radiation is much stronger than the daytime one at the same radiation frequency. The intensity ratio is as large as 9 dB at 11.5 kHz. An experiment directly comparing VLF waves generated by the beat-wave approach and by the amplitude modulation (AM) approach was also conducted. The results rule out the likely contribution of the AM mechanism acting on the electrojet and indicate that beat-wave in the VLF range prefers to be generated in the F region of the ionosphere through the ponderomotive nonlinearity, consistent with the theory. In the nighttime experiment, the ionosphere was underdense to the HF heaters, suggesting a likely setting for effective beat-wave generation of VLF waves by the HF heaters.

  16. The Terminator Time in subionospheric VLF/LF diurnal variation as recorded by the Romanian VLF/LF radio monitoring system related to earthquake occurrence and volcano erruptions

    Science.gov (United States)

    Moldovan, I. A.; Moldovan, A. S.; Biagi, P. F.; Ionescu, C.; Schwingenschuh, K.; Boudjada, M. Y.

    2012-04-01

    The Romanian VLF/LF monitoring system consisting in a radio receiver and the infrastructure that is necessary to record and transmit the collected data is part of the European international network named INFREP. Information on electromagnetic fields' intensities created by transmitters at a receiving site are indicating the quality of the propagation along the paths between the receivers and transmitters. Studying the ionosphere's influences on the electromagnetic waves' propagation along a certain path is a method to put into evidence possible modifications of its lower structure and composition as earthquakes' precursors. The VLF/LF receiver installed in Romania was put into operation in February 2009 and has already 3 years of testing, functioning and proving its utility in the forecast of some earthquakes or volcanic eruptions. Simultaneously we monitor, in the same site with the VLF/LF receiver, the vertical atmospheric electric field and different other meteorological parameters as: temperature, pressure or rainfall. The global magnetic conditions are emphasized with the help of Daily Geomagnetic Index Kp. At a basic level, the adopted analysis consists in a simple statistical evaluation of the signals by comparing the instantaneous values to the trend of the signal. In this paper we pay attention to the terminator times in subionospheric VLF/LF diurnal variation, which are defined as the times of minimum in amplitude (or phase) around sunrise and sunset. These terminator times are found to shift significantly just around the earthquake. In the case of Kobe earthquake, there were found significant shifts in both morning and evening terminator times and these authors interpreted the shift in terminator time in terms of the lowering of lower ionosphere by using the full-wave mode theory. A LabVIEW application which accesses the VLF/LF receiver through internet was developed. This program opens the receiver's web-page and automatically retrieves the list of data

  17. A quantitative comparison of lightning-induced electron precipitation and VLF signal perturbations

    Science.gov (United States)

    Peter, W. B.; Inan, U. S.

    2007-12-01

    VLF signal perturbations recorded on the Holographic Array for Ionospheric/Lightning Research (HAIL) are quantitatively related to a comprehensive model of lightning-induced electron precipitation (LEP) events. The model consists of three major components: a test-particle model of gyroresonant whistler-induced electron precipitation, a Monte Carlo simulation of energy deposition into the ionosphere, and a model of VLF subionospheric signal propagation. For the two representative LEP events studied, the model calculates peak VLF amplitude perturbations within a factor of three of those observed, well within the expected variability of radiation belt flux levels. The phase response of the observed VLF signal to precipitation varied dramatically over the course of the two nights and this variability in phase response is not properly reproduced by the model. The model calculates a peak in the precipitation that is poleward displaced ~6° from the causative lightning flash, consistent with observations. The modeled precipitated energy flux (E > 45 keV) peaks at ~1 × 10-2 (ergs s-1 cm-2), resulting in a peak loss of ~0.001% from a single flux tube at L ~ 2.2, consistent with previous satellite measurements of LEP events. The precipitation calculated by the model is highly dependent on the near-loss-cone trapped radiation belt flux levels assumed, and hence our main objective is not to compare the model calculations and the VLF signal observations on an absolute basis but is rather to develop metrics with which we can characterize the VLF signal perturbations recorded on HAIL in terms of the associated precipitation flux. Metrics quantifying the ionospheric density enhancement (N ILDE) and the electron precipitation (Γ) along a VLF signal path are strongly correlated with the VLF signal perturbations calculated by the model. A conversion ratio Ψ, relating VLF signal amplitude perturbations (ΔA) to the time-integrated precipitation (100-300 keV) along the VLF path (

  18. Systematic errors in VLF direction-finding of whistler ducts

    International Nuclear Information System (INIS)

    Strangeways, H.J.; Rycroft, M.J.

    1980-01-01

    In the previous paper it was shown that the systematic error in the azimuthal bearing due to multipath propagation and incident wave polarisation (when this also constitutes an error) was given by only three different forms for all VLF direction-finders currently used to investigate the position of whistler ducts. In this paper the magnitude of this error is investigated for different ionospheric and ground parameters for these three different systematic error types. By incorporating an ionosphere for which the refractive index is given by the full Appleton-Hartree formula, the variation of the systematic error with ionospheric electron density and latitude and direction of propagation is investigated in addition to the variation with wave frequency, ground conductivity and dielectric constant and distance of propagation. The systematic bearing error is also investigated for the three methods when the azimuthal bearing is averaged over a 2 kHz bandwidth. This is found to lead to a significantly smaller bearing error which, for the crossed-loops goniometer, approximates the bearing error calculated when phase-dependent terms in the receiver response are ignored. (author)

  19. Building and Testing a Portable VLF Receiver

    Science.gov (United States)

    McLaughlin, Robert; Krause, L.

    2014-01-01

    Unwanted emissions or signal noise is a major problem for VLF radio receivers. These can occur from man made sources such as power line hum, which can be prevalent for many harmonics after the fundamental 50 or 60 Hz AC source or from VLF radio transmissions such as LORAN, used for navigation and communications. Natural emissions can also be detrimental to the quality of recordings as some of the more interesting natural emissions such as whistlers or auroral chorus may be drowned out by the more common sferic emissions. VLF receivers must selectively filter out unwanted emissions and amplify the filtered signal to a record-able level without degrading the quality.

  20. Quantitative measurement of lightning-induced electron precipitation using VLF remote sensing

    Science.gov (United States)

    Peter, William Bolton

    This dissertation examines the detection of lightning-induced energetic electron precipitation via subionospheric Very Low Frequency (VLF) remote sensing. The primary measurement tool used is a distributed set of VLF observing sites, the Holographic Array for Ionospheric/Lightning Research (HAIL), located along the eastern side of the Rocky Mountains in the Central United States. Measurements of the VLF signal perturbations indicate that 90% of the precipitation occurs over a region ˜8 degrees in latitudinal extent, with the peak of the precipitation poleward displaced ˜7 degrees from the causative discharge. A comparison of the VLF signal perturbations recorded on the HAIL array with a comprehensive model of LEP events allows for the quantitative measurement of electron precipitation and ionospheric density enhancement with unprecedented quantitative detail. The model consists of three major components: a test-particle model of gyroresonant whistler-induced electron precipitation; a Monte Carlo simulation of energy deposition into the ionosphere; and a model of VLF subionospheric signal propagation. For the two representative LEP events studied, the model calculates peak VLF amplitude and phase perturbations within a factor of three of those observed, well within the expected variability of radiation belt flux levels. The modeled precipitated energy flux (E>45 keV) peaks at ˜1 x 10-2 [ergs s-1 cm -2], resulting in a peak loss of ˜0.001% from a single flux tube at L˜2.2, consistent with previous satellite measurements of LEP events. Metrics quantifying the ionospheric density enhancement (N ILDE) and the electron precipitation (Gamma) are strongly correlated with the VLF signal perturbations calculated by the model. A conversion ratio Psi relates VLF signal amplitude perturbations (DeltaA) to the time-integrated precipitation (100-300 keV) along the VLF path (Psi=Gamma / DeltaA). The total precipitation (100-300 keV) induced by one of the representative LEP

  1. Local coexistance of different phases

    International Nuclear Information System (INIS)

    Narnhofer, H.

    1982-01-01

    Under intuitively reasonable assumptions it is shown that in two dimensions different phases cannot exist locally. In three dimensions we discuss the possibility of local coexistance of districts with different magnetization for the Heisenberg ferromagnet and show that an interaction that breaks rotational invariance is necessary for this phenomenon. (Author)

  2. VLF Observation of Long Ionospheric Recovery Events

    Science.gov (United States)

    Cotts, B. R.; Inan, U. S.

    2006-12-01

    On the evening of 20 November 1992, three early/fast events were observed on the great circle path (GCP) from the NAU transmitter in Puerto Rico to Gander (GA), Newfoundland. These events were found to have significantly longer recovery times (up to 20 minutes) than any previously documented events. Typical early/fast events and Lightning-induced Electron Precipitation (LEP) events affect the D-region ionosphere near the night-time VLF-reflection height of ~85 km and exhibit recovery to pre-event levels of gigantic jets. In this context, preliminary results indicate that the lightning-associated VLF long recovery events appear to be more common in oceanic thunderstorms. In this paper, we present occurrence statistics and other measured properties of VLF long recovery events, observed on all-sea based and land based VLF great circle paths.

  3. Covariant phase difference observables in quantum mechanics

    International Nuclear Information System (INIS)

    Heinonen, Teiko; Lahti, Pekka; Pellonpaeae, Juha-Pekka

    2003-01-01

    Covariant phase difference observables are determined in two different ways, by a direct computation and by a group theoretical method. A characterization of phase difference observables which can be expressed as the difference of two phase observables is given. The classical limits of such phase difference observables are determined and the Pegg-Barnett phase difference distribution is obtained from the phase difference representation. The relation of Ban's theory to the covariant phase theories is exhibited

  4. Terrestrial VLF transmitter injection into the magnetosphere

    Science.gov (United States)

    Cohen, M. B.; Inan, U. S.

    2012-08-01

    Very Low Frequency (VLF, 3-30 kHz) radio waves emitted from ground sources (transmitters and lightning) strongly impact the radiation belts, driving electron precipitation via whistler-electron gyroresonance, and contributing to the formation of the slot region. However, calculations of the global impacts of VLF waves are based on models of trans-ionospheric propagation to calculate the VLF energy reaching the magnetosphere. Limited comparisons of these models to individual satellite passes have found that the models may significantly (by >20 dB) overestimate amplitudes of ground based VLF transmitters in the magnetosphere. To form a much more complete empirical picture of VLF transmitter energy reaching the magnetosphere, we present observations of the radiation pattern from a number of ground-based VLF transmitters by averaging six years of data from the DEMETER satellite. We divide the slice at ˜700 km altitude above a transmitter into pixels and calculate the average field for all satellite passes through each pixel. There are enough data to see 25 km features in the radiation pattern, including the modal interference of the subionospheric signal mapped upwards. Using these data, we deduce the first empirical measure of the radiated power into the magnetosphere from these transmitters, for both daytime and nighttime, and at both the overhead and geomagnetically conjugate region. We find no detectable variation of signal intensity with geomagnetic conditions at low and mid latitudes (L ionospheric heating by one VLF transmitter which modifies the trans-ionospheric absorption of signals from other transmitters passing through the heated region.

  5. Sprites and Early ionospheric VLF perturbations

    Science.gov (United States)

    Haldoupis, Christos; Amvrosiadi, Nino; Cotts, Ben; van der Velde, Oscar; Chanrion, Olivier; Neubert, Torsten

    2010-05-01

    Past studies have shown a correlation between sprites and early VLF perturbations, but the reported correlation varies widely from ~ 50% to 100%. The present study resolves these large discrepancies by analyzing several case studies of sprite and narrowband VLF observations, in which multiple transmitter-receiver VLF links with great circle paths (GCPs) passing near a sprite-producing thunderstorm were available. In this setup, the multiple links act in a complementary way that makes the detection of early VLF perturbations much more probable compared to a single VLF link that can miss several of them, a fact that was overlooked in past studies. The evidence shows that sprites are accompanied by early VLF perturbations in a one-to-one correspondence. This implies that the sprite generation mechanism may cause also sub-ionospheric conductivity disturbances that produce early VLF events. However, the one-to-one "sprite to early" event relationship, if viewed conversely as "early to sprite", appears not to be always reciprocal. This is because the number of early events detected in some cases was considerably larger than the number of sprites. Since the great majority of the early events not accompanied by sprites was caused by positive cloud to ground (+CG) lightning discharges, it is possible that sprites or sprite halos were concurrently present in these events as well but were missed by the sprite-watch detection system. In order for this option to be resolved we need more studies using highly sensitive optical systems capable of detecting weaker sprites, sprite halos and elves.

  6. Development of VLF noise storm and its relation to dynamics of magnetosphere during geomagnetic storms

    International Nuclear Information System (INIS)

    Fedyakina, N.I.; Khorosheva, O.V.

    1989-01-01

    Dependence between the development of geomagnetic storm and VLF noise storm is studied. Two conditions should be met for the development of noise storm in VLF-hiss (f ≅ 0.5-10 kHz): a) threshold intensity of electron fluxes with E e > 40 keV in plasma layers; b) the presence of substorms resulting to widening of electron belt and its collision with cold plasma of plasmasphere. The noise storm at the fixed longitude begins about midnight independently of the phase of magnetic storm; Noise storm duration is connected with geomagnetic storm intensity by direct linear relationship

  7. VLF Wave Properties During Geomagnetic Storms

    Science.gov (United States)

    Blancarte, J.; Artemyev, A.; Mozer, F.; Agapitov, O. V.

    2017-12-01

    Whistler-mode chorus is important for the global dynamics of the inner magnetosphere electron population due to its ability to scatter and accelerate electrons of a wide energy range in the outer radiation belt. The parameters of these VLF emissions change dynamically during geomagnetic storms. Presented is an analysis of four years of Van Allen probe data, utilizing electric and magnetic field in the VLF range focused on the dynamics of chorus wave properties during the enhancement of geomagnetic activity. It is found that VLF emissions respond to geomagnetic storms in more complicated ways than just by affecting the waves' amplitude growth or depletion. Oblique wave amplitudes grow together with parallel waves during periods of intermediate geomagnetic activity, while the occurrence rate of oblique waves decreases during larger geomagnetic storms.

  8. World map of ELF/VLF emissions as observed by a low-orbiting satellite

    International Nuclear Information System (INIS)

    Parrot, M.

    1990-01-01

    Statistical studies were performed of the intensities of the ELF/VLF emissions observed by the low-orbiting satellite AUREOL-3. Data were obtained from filterbanks and the frequency range of observations extends from a few tens of Hz up to 15 kHz. The most important phenomena observed are ELF hiss and VLF hiss. Electric and magnetic components are used. Thus, representation of the waves intensities in geographical coordinates was made at different frequencies. The relative ability of natural waves (whistler, hiss) and man-made waves, such as powerful VLF transmitters or powerline harmonic radiations (PLHR), to precipitate particles in the slot region, is studied. Using geomagnetical representation, it is shown that ELF hiss is maximum between 06 and 20 Magnetic Local Time and in the invariant latitude range 50 0 -70 0 as usual, but geographic representation indicates that the waves are intensified at the longitudes of VLF transmitters and near the South Atlantic Anomaly (SAA). The SAA plays a dominant role in the localization of the strongest ELF hiss. Weakest intensities are observed to the east of the SAA. As to the VLF hiss, the maximum intensity is related to regions of enhanced thunderstorm activity, and may be influenced by powerline harmonic radiations (PLHR) over USA. Comparisons with past work, experimental as well as theoretical, are made

  9. VLF wave generation by beating of two HF waves in the ionosphere

    Science.gov (United States)

    Kuo, Spencer; Snyder, Arnold; Kossey, Paul; Chang, Chia-Lie; Labenski, John

    2011-05-01

    Theory of a beat-wave mechanism for very low frequency (VLF) wave generation in the ionosphere is presented. The VLF current is produced by beating two high power HF waves of slightly different frequencies through the nonlinearity and inhomogeneity of the ionospheric plasma. Theory also shows that the density irregularities can enhance the beat-wave generation. An experiment was conducted by transmitting two high power HF waves of 3.2 MHz and 3.2 MHz + f, where f = 5, 8, 13, and 2.02 kHz, from the HAARP transmitter. In the experiment, the ionosphere was underdense to the O-mode heater, i.e., the heater frequency f0 > foF2, and overdense or slightly underdense to the X-mode heater, i.e., f0 < fxF2 or f0 ≥ fxF2. The radiation intensity increased with the VLF wave frequency, was much stronger with the X-mode heaters, and was not sensitive to the electrojet. The strongest VLF radiation of 13 kHz was generated when the reflection layer of the X-mode heater was just slightly below the foF2 layer and the spread of the O-mode sounding echoes had the largest enhancement, suggesting an optimal setting for beat-wave generation of VLF waves by the HF heaters.

  10. Comparisons of Measurements and Modeling of Solar Eclipse Effects on VLF Transmissions

    Science.gov (United States)

    Eccles, J. V.; Rice, D. D.; Sojka, J. J.; Marshall, R. A.; Drob, D. P.; Decena, J. C.

    2017-12-01

    The solar eclipse of 2017 August 21 provides an excellent opportunity to examine Very Low Frequency (VLF) radio signal propagation through the path of the solar eclipse between Navy VLF transmitters and several VLF receivers. The VLF transmitters available for this study radio signal propagation study are NLK in Jim Creek, Washington (24.8 kHz, 192 kW, 48.20N, 121.90W), NML in LaMour, North Dakota (25.2 kHz, 500 kW 46.37N, 93.34W), and NAA in Cutler, Maine (24.0 kHz, 1000 kW, 44.65N, 67.29W). These VLF transmitters provide propagation paths to three VLF receivers at Utah State University (41.75N, 111.76W), Bear Lake Observatory (41.95N, 111.39W), Salt Lake City (40.76N, 111.89W) and one receiver in Boulder, Colorado (40.02N, 105.27W). The solar eclipse shadow will cross all propagations paths during the day and will modify the D region electron density within the solar shadow. The week prior to the solar eclipse will be used to generate a diurnal baseline of VLF single strength for each transmitter-receiver pair. These will be compared to the day of the solar eclipse to identify VLF propagation differences through the solar eclipse shawdow. Additionally, the electron density effects of the week prior and of the solar eclipse day will be modeled using the Data-Driven D Region (DDDR) model [Eccles et al., 2005] with a detailed eclipse solar flux mask. The Long-Wave Propagation Code and the HASEL RF ray-tracing code will be used to generate VLF signal strength for each measured propagation path through the days prior and the solar eclipse day. Model-measurement comparisons will be presented and the D region electron density effects of the solar eclipse will be examined. The DDDR is a time-dependent D region model, which makes it very suitable for the solar eclipse effects on the electron density for the altitude range of 36 to 130 km. Eccles J. V., R. D. Hunsucker, D. Rice, J. J. Sojka (2005), Space weather effects on midlatitude HF propagation paths: Observations and

  11. The nonlinear gyroresonance interaction between energetic electrons and coherent VLF waves propagating at an arbitrary angle with respect to the earth's magnetic field

    Science.gov (United States)

    Bell, T. F.

    1984-01-01

    A theory is presented of the nonlinear gyroresonance interaction that takes place in the magnetosphere between energetic electrons and coherent VLF waves propagating in the whistler mode at an arbitrary angle psi with respect to the earth's magnetic field B-sub-0. Particularly examined is the phase trapping (PT) mechanism believed to be responsible for the generation of VLF emissions. It is concluded that near the magnetic equatorial plane gradients of psi may play a very important part in the PT process for nonducted waves. Predictions of a higher threshold value for PT for nonducted waves generally agree with experimental data concerning VLF emission triggering by nonducted waves.

  12. Anomalies in vlf propagation and possible interpretations

    International Nuclear Information System (INIS)

    Shubova, R.S.; Knyazeva, N.A.; Sopel'nikov, M.D.

    1985-01-01

    This study considers cases of anomalous increase in the amplitude of a vlf signal on the Rugby-Khar'kov path. It is shown that such increases may be caused by change in the ratio of normal wave amplitudes, due to a decrease in electron concentration at the lower boundary of the ionosphere

  13. VLF Technique and Science in India

    International Nuclear Information System (INIS)

    Chakravarty, S. C.

    2010-01-01

    Since IGY period (1957-58), natural and artificially produced Very Low Frequency (VLF) electromagnetic radiations are being recorded at large number of ground stations and on board satellites to study various wave-plasma interactive phenomena. The terrestrial propagation of these VLF radio waves are primarily enabled through the earth ionosphere wave guide (EIWG) system to long horizontal distances around the globe and ducted along the geomagnetic field lines into the conjugate hemisphere through the ionosphere-plasmasphere-magnetosphere routes. The time frequency spectra indicate presence of dispersion and various cut-off frequencies providing several types of received signals like whistlers, chorus, tweeks, hiss, hisslers etc., which can be heard on an earphone with distinguishing audio structures. While the VLF technique has been a very effective tool for studying middle and high latitude phenomena, the importance of various anomalous characteristics over the Indian low latitude stations provide potentially new challenges for their scientific interpretation and modelling. The ducted and non-ducted propagation, low latitude TRIMPI/TLE effects, D-region ionisation perturbations due to solar and stellar x- and γ ray emissions and detecting precursors of seismic activities are a few problems which will gain from low latitude studies. Since the conjugate points of Indian stations lie over the Indian oceanic region, the VLF propagation effects would be relatively noise free to observe rare and new phenomena requiring better SNR to detect such changes. The VLF signals emanating from the active seismic zones would require high sensitivity of the system and suitable network of transmitting and receiving stations. Results obtained on whistlers and related studies from a number of Indian stations covering geomagnetic latitude range between 13-24 deg. N are mentioned and reviewed in the background of theoretical understanding of the lightning return stroke signal elements

  14. Frequency-time behavior of artificially stimulated vlf emissions

    International Nuclear Information System (INIS)

    Stiles, G.S.; Helliwell, R.A.

    1975-01-01

    Artificially stimulated VLF emissions (ASE's) are emissions triggered in the magnetosphere by the whistler mode signals from VLF transmitters. These emissions may be separated into two classes, rising and falling, depending on whether the final value of df/dt is positive or negative. Several hundred ASE's triggered by three transmitters have been analyzed using the fast Fourier transform with a filter spacing of 25 Hz and an effective filter width of about 45 Hz. The study was limited to the initial frequency-time behavior of ASE's. Averages taken over many events reveal that both rising and falling tones show the same initial behavior. The emissions begin at the frequency of the triggering signal. Both tones initially rise in frequency, falling tones reversing slope at a point 25--300 Hz above the triggering signal. The slope of rising tones, particularly those triggered by NAA, often abruptly levels off in this same frequency range; as a result, a short (approximately 40 ms) plateau is formed that precedes the final rising phase. The initial frequency offset commonly observed in individual events appears to result from the frequent coincidence with this plateau of a peak in amplitude. Emissions stimulated by all three transmitters show essentially the same features; this finding indicates that their frequency behavior does not depend strongly on transmitter power. The process appears to be asymmetric in frequency; no evidence of initial growth below the triggering frequency has been found. (U.S.)

  15. Estimating Parameters for the Earth-Ionosphere Waveguide Using VLF Narrowband Transmitters

    Science.gov (United States)

    Gross, N. C.; Cohen, M.

    2017-12-01

    Estimating the D-region (60 to 90 km altitude) ionospheric electron density profile has always been a challenge. The D-region's altitude is too high for aircraft and balloons to reach but is too low for satellites to orbit at. Sounding rocket measurements have been a useful tool for directly measuring the ionosphere, however, these types of measurements are infrequent and costly. A more sustainable type of measurement, for characterizing the D-region, is remote sensing with very low frequency (VLF) waves. Both the lower ionosphere and Earth's ground strongly reflect VLF waves. These two spherical reflectors form what is known as the Earth-ionosphere waveguide. As VLF waves propagate within the waveguide, they interact with the D-region ionosphere, causing amplitude and phase changes that are polarization dependent. These changes can be monitored with a spatially distributed array of receivers and D-region properties can be inferred from these measurements. Researchers have previously used VLF remote sensing techniques, from either narrowband transmitters or sferics, to estimate the density profile, but these estimations are typically during a short time frame and over a narrow propagation region. We report on an effort to improve the understanding of VLF wave propagation by estimating the commonly known h' and beta two parameter exponential electron density profile. Measurements from multiple narrowband transmitters at multiple receivers are taken, concurrently, and input into an algorithm. The cornerstone of the algorithm is an artificial neural network (ANN), where input values are the received narrowband amplitude and phase and the outputs are the estimated h' and beta parameters. Training data for the ANN is generated using the Navy's Long-Wavelength Propagation Capability (LWPC) model. Emphasis is placed on profiling the daytime ionosphere, which has a more stable and predictable profile than the nighttime. Daytime ionospheric disturbances, from high solar

  16. VLF emissions and whistlers observed during geomagnetic storms

    Science.gov (United States)

    Ondoh, T.; Tanaka, Y.; Nishizaki, R.; Nagayama, M.

    1974-01-01

    Whistler-triggered emissions and a narrowband hiss are described which were observed over Japan by ISIS 2 during the main phase of the geomagnetic storm of August 9, 1972. The characteristics of the narrowband hiss and increases in the whistler rate during the storm are discussed, and the ISIS-2 data are compared with data on whistler cutoffs and VLF noise breakups obtained by OGO 4 and Alouette I. Since the whistlers and narrowband hiss are usually observed inside and outside the plasmapause, it is thought that the plasmapause may have been located near the low-latitude end of the narrowband hiss during the main phase of the storm. It is suggested that the increases in the whistler rate may have been caused by the formation of whistler ducts in the disturbed plasmapause.

  17. Substorms during different storm phases

    Directory of Open Access Journals (Sweden)

    N. Partamies

    2011-11-01

    Full Text Available After the deep solar minimum at the end of the solar cycle 23, a small magnetic storm occurred on 20–26 January 2010. The Dst (disturbance storm time index reached the minimum of −38 nT on 20 January and the prolonged recovery that followed the main phase that lasted for about 6 days. In this study, we concentrate on three substorms that took place (1 just prior to the storm, (2 during the main phase of the storm, and (3 at the end of the recovery of the storm. We analyse the solar wind conditions from the solar wind monitoring spacecraft, the duration and intensity of the substorm events as well as the behaviour of the electrojet currents from the ground magnetometer measurements. We compare the precipitation characteristics of the three substorms. The results show that the F-region electron density enhancements and dominant green and red auroral emission of the substorm activity during the storm recovery resembles average isolated substorm precipitation. However, the energy dissipated, even at the very end of a prolonged storm recovery, is very large compared to the typical energy content of isolated substorms. In the case studied here, the dissipation of the excess energy is observed over a 3-h long period of several consecutive substorm intensifications. Our findings suggest that the substorm energy dissipation varies between the storm phases.

  18. Auroral pulsations and accompanying VLF emissions

    Directory of Open Access Journals (Sweden)

    V. R. Tagirov

    Full Text Available Results of simultaneous TV observations of pulsating auroral patches and ELF-VLF-emissions in the morning sector carried out in Sodankylä (Finland on February 15, 1991 are presented. Auroral pulsating activity was typical having pulsating patches with characteristic periods of about 7 s. Narrow-band hiss emissions and chorus elements at intervals of 0.3–0.4 s formed the main ELF-VLF activity in the frequency range 1.0–2.5 kHz at the same time. The analysis of auroral images with time resolution of 0.04 s allowed perfectly separate analysis of spatial and temporal variations in the auroral luminosity. Mutual correspondence between the behaviour of the luminous auroral patches and the appearance of ELF noise type hiss emissions and VLF chorus trains was found in two intervals chosen for analysis. While the hiss emissions were associated with the appearance of luminosity inside a limited area close to the zenith, the structured VLF emissions were accompanied by rapid motion of luminosity inside the area. The spatial dimension of the pulsating area was about 45–50 km and luminosity propagated inside it with velocity of about 10–12 kms. We discuss a new approach to explain the 5–15 s auroral pulsation based on the theory of flowing cyclotron maser and relaxation characteristics of ionosphere.

    Key words. Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions · Space plasma physics (wave-particle interactions

  19. Long recovery VLF perturbations associated with lightning discharges

    Science.gov (United States)

    Salut, M. M.; Abdullah, M.; Graf, K. L.; Cohen, M. B.; Cotts, B. R. T.; Kumar, Sushil

    2012-08-01

    Long D-region ionospheric recovery perturbations are a recently discovered and poorly understood subcategory of early VLF events, distinguished by exceptionally long ionospheric recovery times of up to 20 min (compared to more typical ˜1 min recovery times). Characteristics and occurrence rates of long ionospheric recovery events on the NWC transmitter signal recorded at Malaysia are presented. 48 long recovery events were observed. The location of the causative lightning discharge for each event is determined from GLD360 and WWLLN data, and each discharge is categorized as being over land or sea. Results provide strong evidence that long recovery events are attributed predominately to lightning discharges occurring over the sea, despite the fact that lightning activity in the region is more prevalent over land. Of the 48 long recovery events, 42 were attributed to lightning activity over water. Analysis of the causative lightning of long recovery events in comparison to all early VLF events reveals that these long recovery events are detectable for lighting discharges at larger distances from the signal path, indicating a different scattering pattern for long recovery events.

  20. The impact of PMSE and NLC particles on VLF propagation

    Directory of Open Access Journals (Sweden)

    D. Nunn

    2004-04-01

    Full Text Available PMSE or Polar Mesosphere Summer Echoes are a well-known phenomenon in the summer northern polar regions, in which anomalous VHF/UHF radar echoes are returned from heights ~85km. Noctilucent clouds and electron density biteouts are two phenomena that sometimes occur together with PMSE. Electron density biteouts are electron density depletion layers of up to 90%, which may be several kms thick. Using the NOSC Modefndr code based on Wait's modal theory for subionospheric propagation, we calculate the shifts in received VLF amplitude and phase that occur as a result of electron density biteouts. The code assumes a homogeneous background ionosphere and a homogeneous biteout layer along the Great Circle Path (GCP corridor, for transmitter receiver path lengths in the range of 500–6000km.

    For profiles during the 10h about midnight and under quiet geomagnetic conditions, where the electron density at 85km would normally be less than 500el/cc, it was found that received signal perturbations were significant, of the order of 1–4dB and 5–40° of phase. Perturbation amplitudes increase roughly as the square root of frequency. At short range perturbations are rather erratic, but more consistent at large ranges, readily interpretable in terms of the shifts in excitation factor, attenuation factor and v/c ratios for Wait's modes. Under these conditions such shifts should be detectable by a well constituted experiment involving multiple paths and multiple frequencies in the north polar region in summer. It is anticipated that VLF propagation could be a valuable diagnostic for biteout/PMSE when electron density at 85km is under 500el/cc, under which circumstances PMSE are not directly detectable by VHF/UHF radars.

    Key words. Electromagnetism (wave propagation – Ionosphere (polar ionosphere – Radioscience (ionospheric propagation

  1. The Radio And Very Low Frequency (VLF) Electromagnetic ...

    African Journals Online (AJOL)

    The Radio And Very Low Frequency (VLF) Electromagnetic Response Of A Layered Earth Media With Variable Dielectric Permittivity. ... A radio frequency of 125 KHz and a very low frequency (VLF) of 20 KHz were used in the computations and the field parameters studied over a dimensionless induction number, B. The ...

  2. Electric fields and currents induced in organs of the human body when exposed to ELF and VLF electromagnetic fields

    Science.gov (United States)

    King, Ronold W. P.; Sandler, Sheldon S.

    1996-09-01

    Formulas for the transverse components of the electric and magnetic fields of the traveling-wave currents of three different types of three-wire, three-phase high-voltage power lines and of a typical VLF transmitter are given. From them, exposure situations for the human body are chosen which permit the analytical determination of the total current induced in that body. With this, the fraction of the total axial current, the axial current density, and the axial electric field in each organ of the body are obtained at any desired cross section. The dimensions and conductivity of these organs must be known. The electric field so obtained is the average macroscopic field in which the cells in each organ are immersed when the whole body is exposed to a known incident field. It corresponds in vivo to the electric field used in vitro to expose cells in tissues.

  3. Strange VLF bursts in northern Scandinavia: case study of the afternoon "mushroom-like" hiss on 8 December 2013

    Directory of Open Access Journals (Sweden)

    J. Manninen

    2015-08-01

    Full Text Available We investigate a non-typical very low frequency (VLF 1–4 kHz hiss representing a sequence of separated noise bursts with a strange "mushroom-like" shape in the frequency–time domain, each one lasting several minutes. These strange afternoon VLF emissions were recorded at Kannuslehto (KAN, ϕ = 67.74° N, λ = 26.27° E; L ∼ 5.5 in northern Finland during the late recovery phase of the small magnetic storm on 8 December 2013. The left-hand (LH polarized 2–3 kHz "mushroom caps" were clearly separated from the right-hand (RH polarized "mushroom stems" at the frequency of about 1.8–1.9 kHz, which could match the lower ionosphere waveguide cutoff (the first transverse resonance of the Earth–ionosphere cavity. We hypothesize that this VLF burst sequence could be a result of the modulation of the VLF hiss electron–cyclotron instability from the strong Pc5 geomagnetic pulsations observed simultaneously at ground-based stations as well as in the inner magnetosphere by the Time History of Events and Macroscale Interactions during Substorms mission probe (THEMIS-E; ThE. This assumption is confirmed by a similar modulation of the intensity of the energetic (1–10 keV electrons simultaneously observed by the same ThE spacecraft. In addition, the data of the European Incoherent Scatter Scientific Association (EISCAT radar at Tromsø show a similar quasi-periodicity in the ratio of the Hall-to-Pedersen conductance, which may be used as a proxy for the energetic particle precipitation enhancement. Our findings suggest that this strange mushroom-like shape of the considered VLF hiss could be a combined mutual effect of the magnetospheric ULF–VLF (ultra low frequency–very low frequency wave interaction and the ionosphere waveguide propagation.

  4. Observation of magntosphere and ionosphere through HF and VLF standard waves

    International Nuclear Information System (INIS)

    Ogawa, Toru

    1974-01-01

    The observation of magnetosphere and ionosphere through HF and VLF standard waves is a part of the IMS research subject I on the structure and dynamics of the earth's plasmasphere. By receiving the HF and VLF standard waves with high accuracy, and through the changes of the phase and frequency, continuous observation is made concerning the lower plasmasphere at equator and middle/low latitudes and the upper layers in polar regions. In this way, the dynamic state at the time of disturbance such as magnetic storm can be explored. The following matters are described: features of standard-wave observation, purpose and observation plans, the exhcange of data with overseas countries and satellites, and the results of observation expected. (Mori, K.)

  5. VLF imaging of the Venus foreshock

    Science.gov (United States)

    Crawford, G. K.; Strangeway, R. J.; Russell, C. T.

    1993-01-01

    VLF plasma wave measurements obtained from the Pioneer Venus Orbiter Electric Field Detector (OEFD) have been used to construct statistical images of the Venus foreshock. Our data set contains all upstream measurements from an entire Venus year (approximately 200 orbits). Since the foreshock VLF characteristics vary with Interplanetary Magnetic Field (IMF) orientation we restrict the study to IMF orientations near the nominal Parker spiral angle (25 to 45). Our results show a strong decrease in 30 kHz wave intensity with both foreshock depth and distance. There is also an asymmetry in the 30 kHz emissions from the upstream and downstream foreshocks. The ion foreshock is characterized by strong emissions in the 5.4 kHz OEFD channel which are positioned much deeper in the foreshock than expected from terrestrial observations. No activity is observed in the region where field aligned ion distributions are expected. ULF wave activity, while weaker than at Earth, shows similar behavior and may indicate the presence of similar ion distributions.

  6. Applications of the VLF induction method for studying some volcanic processes of Kilauea volcano, Hawaii

    Science.gov (United States)

    Zablocki, C.J.

    1978-01-01

    The very low-frequency (VLF) induction method has found exceptional utility in studying various volcanic processes of Kilauea volcano, Hawaii because: (1) significant anomalies result exclusively from ionically conductive magma or still-hot intrusions (> 800??C) and the attendant electrolytically conductive hot groundwater; (2) basalt flows forming the bulk of Kilauea have very high resistivities at shallow depths that result in low geologic noise levels and relatively deep depths of investigation (???100 m); and (3) the azimuths to two of the usable transmitters (NLK and NPM) are aligned favorably with most of the principal geologic features. Measurements of the tilt angle and ellipticity of the polarization ellipse of the magnetic field, using a simple, hand-held receiver, have been used to: (1) delineate the lateral extent of shallow, partially solidified lava lakes, active lava tubes, and recent intrusive dikes; (2) obtain an indication of the attitude of some recent dikes; (3) show that many eruptive fissures cool faster than their intrusive counterparts; (4) show that some fumarolic areas are underlain by shallow, highly altered, and conductive zones; and (5) provide control information for interpreting data obtained with other electrical techniques. Complementary measurements of scalar apparent resistivity and surface impedance phase, using a new attachment for the VLF receiver, have substantially increased the utility of VLF studies in Kilauea. They provide better lateral resolution of conductors and reduce the ambiguity in interpretation. Notwithstanding recent advances in theoretical modeling techniques, the excellent quality of some of the data warrants extension of interpretive techniques, particularly for quantitatively characterizing the configuration and conductivity of small-dimension bodies. These VLF induction methods should have wide application to studies of active volcanic regions in other parts of the world and could provide some insights into

  7. Phase Difference Measurement Method Based on Progressive Phase Shift

    Directory of Open Access Journals (Sweden)

    Min Zhang

    2018-06-01

    Full Text Available This paper proposes a method for phase difference measurement based on the principle of progressive phase shift (PPS. A phase difference measurement system based on PPS and implemented in the FPGA chip is proposed and tested. In the realized system, a fully programmable delay line (PDL is constructed, which provides accurate and stable delay, benefitting from the feed-back structure of the control module. The control module calibrates the delay according to process, voltage and temperature (PVT variations. Furthermore, a modified method based on double PPS is incorporated to improve the resolution. The obtained resolution is 25 ps. Moreover, to improve the resolution, the proposed method is implemented on the 20 nm Xilinx Kintex Ultrascale platform, and test results indicate that the obtained measurement error and clock synchronization error is within the range of ±5 ps.

  8. Determination of Spatio-Temporal Characteristics of D-region Electron Density during Annular Solar Eclipse from VLF Network Observations

    Science.gov (United States)

    Basak, T.; Hobara, Y.

    2015-12-01

    A major part of the path of the annular solar eclipse of May 20, 2012 (magnitude 0.9439) was over southern Japan. The D-region ionospheric changes associated with that eclipse, led to several degree of observable perturbations of sub-ionospheric very low frequency (VLF) radio signal. The University of Electro-Communications (UEC) operates VLF observation network over Japan. The solar eclipse associated signal changes were recorded in several receiving stations (Rx) simultaneously for the VLF signals coming from NWC/19.8kHz, JJI/22.2kHz, JJY/40.0kHz, NLK/24.8kHz and other VLF transmitters (Tx). These temporal dependences of VLF signal perturbation have been analyzed and the spatio-temporal characteristics of respective sub-ionospheric perturbations has already been studied by earlier workers using 2D-Finite Difference Time Domain method of simulation. In this work, we determine the spatial scale, depth and temporal dependence of lower ionospheric perturbation in consistence with umbral and penumbral motion. We considered the 2-parameter D-region ionospheric model with exponential electron density profile. To model the solar obscuration effect over it, we assumed a generalized space-time dependent 2-dimensional elliptical Gaussian distribution for ionospheric parameters, such as, effective reflection height (h') and sharpness factor (β). The depth (△hmax, △βmax), center of shadow (lato(t), lono(t)) and spatial scale (σlat,lon) of that Gaussian distribution are used as model parameters. In the vicinity of the eclipse zone, we compute the VLF signal perturbations using Long Wave Propagation Capability (LWPC) code for several signal propagation paths. The propagation path characteristics, such as, ground and water conductivity and geomagnetic effect on ionosphere are considered from standard LWPC prescriptions. The model parameters are tuned to set an optimum agreement between our computation and observed positive and negative type of VLF perturbations. Thus

  9. The properties of ULF/VLF signals generated by the SURA facility without ionospheric currents modulation

    Science.gov (United States)

    Kotik, D. S.; Raybov, A. V.; Ermakova, E. N.

    2012-12-01

    During the last three years the comprehensive study of ionospheric generation of the artificial signals in ULF/VLF band was carried out at SURA facility. This research was stimulated by successive HAARP experiments on detection the low frequency signals genreated due the action of the ponderomotive forces. Two experimental campaigns under different ionospheric, geomagnetic and facility operation mode conditions was undertaken every year from 2010 to 2012. Here we are summarizing the main features of the artificial ULF/VLF signals observed in vicinity the SURA site. The signals in the 2-20 Hz band were observed in the small area around the facility with the radius approximately 15 km. It was not signal detection at the 30 km distance. The maximum of the amplitude was detected in the nearest receiving point about 3 km away from the transmitting array. The amplitude increased about 3 times when the beam was inclined on16 degrees to the south so the footprint of the geomagnetic field line comes close to the point of observation. The ULF signals increased slightly when the SURA operating frequency overlaps the critical foF2 frequency. As a rule the daytime signals are smaller then nighttime one. No any correlation was observed with geomagnetic disturbances. The time delay of the ionospheric ULF signals measured by phase method was estimated as 300-400 ms. Polarization of the ULF signals has a pronounced elliptical character. Sometimes it was linear. The part of measurements in June 2012 was coincide with magnetic storm (June 16-18, Kp=6). It was observed broadening of the signal line at frequencies of 11 and 17 Hz up to 0.2 Hz at the recovery stage of the storm at June 18 (see the figure). This fact can be interpreted as the result of the signal interaction with the radiation belt protons appeared over there during the storm time. In 2012 campaigns it was firstly observed at SURA signals on frequencies of several kilohertz at nightime which could not be explained by

  10. VLF wave injections from the ground

    Science.gov (United States)

    Helliwell, R. A.

    1983-01-01

    Experiments on wave-particle interactions using VLF whistler-mode waves injected into the magnetosphere from Antartica are described. The injected signals are single-frequency coherent waves whose amplitudes and frequencies may be changed slowly with time, or else two or more coherent wave trains transmitted simultaneously to determine the nature of the response to multifrequency excitation. The waves may be amplified 30 dB or more and may trigger intense emissions having bandwidths that vary from a few to several hundred Hertz. In most cases significant growth and triggering occur only when the driving signal is essentially monochromatic (bandwidth 10 Hz). If two frequencies are transmitted simultaneously the signal at the lower frequency tends to be suppressed by 20 dB or more. These results are interpreted in terms of a feedback interaction between the waves and counter-streaming cyclotron resonant electrons in a region several hundred wavelengths long, centered on the magnetic equator.

  11. Sex Differences in Countermovement Jump Phase Characteristics

    Directory of Open Access Journals (Sweden)

    John J. McMahon

    2017-01-01

    Full Text Available The countermovement jump (CMJ is commonly used to explore sex differences in neuromuscular function, but previous studies have only reported gross CMJ measures or have partly examined CMJ phase characteristics. The purpose of this study was to explore differences in CMJ phase characteristics between male and female athletes by comparing the force-, power-, velocity-, and displacement-time curves throughout the entire CMJ, in addition to gross measures. Fourteen men and fourteen women performed three CMJs on a force platform from which a range of kinetic and kinematic variables were calculated via forward dynamics. Jump height (JH, reactive strength index modified, relative peak concentric power, and eccentric and concentric displacement, velocity, and relative impulse were all greater for men (g = 0.58–1.79. Relative force-time curves were similar between sexes, but relative power-, velocity-, and displacement-time curves were greater for men at 90%–95% (immediately before and after peak power, 47%–54% (start of eccentric phase and 85%–100% (latter half of concentric phase, and 65%–87% (bottom of countermovement and initial concentric phase of normalized jump time, respectively. The CMJ distinguished between sexes, with men demonstrating greater JH through applying a larger concentric impulse and, thus, achieving greater velocity throughout most of the concentric phase, including take-off.

  12. D-region Ionospheric Imaging Using VLF/LF Broadband Sferics, Forward Modeling, and Tomography

    Science.gov (United States)

    McCormick, J.; Cohen, M.

    2017-12-01

    The D-region of the ionosphere (60-90 km altitude) is highly variable on timescales from fractions of a second to many hours, and on spatial scales from 10 km to many hundreds of km. VLF and LF (3-30kHz, 30-300kHz) radio waves are guided to global distances by reflecting off of the ground and the D-region, making the Earth-ionosphere waveguide (EIWG). Therefore, information about the current state of the ionosphere is encoded in received VLF/LF radio waves since they act like probes of the D-region. The return stroke of lightning is an impulsive event that radiates powerful broadband radio emissions in VLF/LF bands known as `radio atmospherics' or `sferics'. Lightning flashes occur about 40-50 times per second throughout the Earth. An average of 2000 lightning storms occur each day with a mean duration of 30 minutes creating a broad spatial and temporal distribution of lightning VLF/LF sources. With careful processing, we can recover high fidelity measurements of amplitude and phase of both the radial and azimuthal magnetic field sferic components. By comparison to a theoretical EIWG propagation model such as the Long Wave Propagation Capability (LWPC) developed by the US Navy, with a standard forward modeling approach, we can infer information about the current state of the D-region. Typically, the ionosphere is parametrized to reduce the dimensionality of the problem which usually results in an electron density vs altitude profile. For large distances (Greater than 1000 km), these results can be interpreted as path-averaged information. In contrast to studies using navy transmitters to study the D-region, the full spectral information allows for more complete information and less ambiguous inferred ionospheric parameters. With the spatial breadth of lightning sources taken together with a broadly distributed VLF/LF receiver network, a dense set of measurements are acquired in a tomographic sense. Using the wealth of linear algebra and imaging techniques it is

  13. Magnetosphere VLF observation by satellite ISIS

    International Nuclear Information System (INIS)

    Ondo, Tadanori; Nakamura, Yoshikatsu; Watanabe, Shigeaki; Murakami, Toshimitsu

    1978-01-01

    On the basis of the VLF (50 Hz -- 30 kHz) electric field data from the satellite ISIS, the following works carried out in The Radio Research Laboratories are described: deuteron whistler and whistler duct, detection of plasmapause by LHR hiss, and the origin of 5 kHz hiss at low/middle latitudes. The deuteron whistlers are observable distinctly only at low latitude because of gyro-frequency and the frequency resolution of spectral analyzers. Whistler echo occurs when a whistler moves back and forth through a duct along the line of magnetic force, so it is considered that the ISIS satellite crosses the duct. The variation in ion composition around plasmapause obtained through LHR hiss is explainable by the plasamapause position and the magnetic storm effect on the plasamapause. Concerning the narrow band hiss of 5 kHz +- 1.0 kHz frequently observed on the ground at low/middle latitudes, it may occur around plasmapause, propagate through the ionosphere and then to the ground in waveguide mode, or otherwise, it may occur above the ionosphere and then propagate directly to the ground penetrating through the ionosphere. (J.P.N.)

  14. Ionospheric turbulence from ground-based and satellite VLF/LF transmitter signal observations for the Simushir earthquake (November 15, 2006

    Directory of Open Access Journals (Sweden)

    Pier Francesco Biagi

    2012-04-01

    Full Text Available

    Signals from very low frequency (VLF/ low frequency (LF transmitters recorded on the ground station at Petropavlovsk-Kamchatsky and on board the French DEMETER satellite were analyzed for the Simushir earthquake (M 8.3; November 15, 2006. The period of analysis was from October 1, 2006, to January 31, 2007. The ground and satellite data were processed by a method based on the difference between the real signal at night-time and the model signal. The model for the ground observations was the monthly averaged signal amplitudes and phases, as calculated for the quiet days of every month. For the satellite data, a two-dimensional model of the signal distribution over the selected area was constructed. Preseismic effects were found several days before the earthquake, in both the ground and satellite observations.

     

  15. Calculated optical absorption of different perovskite phases

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2015-01-01

    We present calculations of the optical properties of a set of around 80 oxides, oxynitrides, and organometal halide cubic and layered perovskites (Ruddlesden-Popper and Dion-Jacobson phases) with a bandgap in the visible part of the solar spectrum. The calculations show that for different classes...... of perovskites the solar light absorption efficiency varies greatly depending not only on bandgap size and character (direct/indirect) but also on the dipole matrix elements. The oxides exhibit generally a fairly weak absorption efficiency due to indirect bandgaps while the most efficient absorbers are found...... in the classes of oxynitride and organometal halide perovskites with strong direct transitions....

  16. Electron precipitation and VLF emissions associated with cyclotron resonance interactions near the plasmapause

    International Nuclear Information System (INIS)

    Foster, J.C.; Rosenberg, T.J.

    1976-01-01

    Correlated bursts of bremsstrahlung X rays and VLF emissions were recorded for approx.25 min at Siple Station, Antarctica, on January 2, 1971. The burst occurred quasi-periodically with spectral power predominantly in the period range 4--12 s. A typical VLF burst consisted of 3--5 rising elements of approx.0.1-s duration separated by approx.0.15 s and was confined to the frequency range 1.5--3.8 kHz. Evidence is presented to show that the bursts were triggered by the low-frequency tail of whistlers propagating from the northern hemisphere. The interpretation of the observations in terms of an equatorial cyclotron resonance interaction occurring at the outer edge of the plasmapause on the L=4.2 field line, offered initially by Rosenberg et al. (1971), is given further support by the more extensive analysis presented here of the electron energy-wave frequency relationship in the bursts and the propagation times for the resonant waves and electrons. It is inferred from the X ray data that the equatorial flux of trapped electrons was probably anisotropic and near the stable trapping limit at the time of this event. It is suggested that an important effect of the trigger signal is the increase of the anisotropy of the resonant electrons. Wave growth rates calculated in the random phase approximation for electron pitch angle distributions that might apply in this event can explain certain features of the VLF and precipitation data during and between the bursts

  17. Cultural differences in cognition: Rosetta Phase I.

    Science.gov (United States)

    Klein, Helen Altman; Lin, Mei-Hua; Radford, Mark; Masuda, Takahiko; Choi, Incheol; Lien, Yunnwen; Yeh, Yeiyuh; Boff, Kenneth R

    2009-10-01

    Cultural differences in cognition are important during multinational commercial, military, and humanitarian operations. The Rosetta Project addresses definition and measurement of key cognitive dimensions. Six potential diagnostic measures related to Analytic-Holistic reasoning were assessed: the Exclusion Task, the Attribution Complexity Scale, the Syllogism Task, Categorization, the Framed Line Test, and the Facial Expression Task. 379 participants' ages ranged from 17 to 24 years (M = 19.8, SD = 1.4). 64.6% were women; Eastern Asian groups (Japan, Korea, and Taiwan) were assumed to have Holistic reasoning tendencies, and those from a Western group (USA) were assumed to have Analytic tendencies. Participants were recruited from subject pools in psychology using the procedures of each university. Results on the Exclusion and Categorization Tasks confirmed hypothesized differences in Analytic-Holistic reasoning. The Attribution Complex-ity Scale and the Facial Expression Task identified important differences among the four groups. Outcomes on the final two tasks were confounded by unrelated group differences, making comparisons difficult. Building on this exploratory study, Rosetta Phase II will include additional groups and cognitive tasks. Measures of complex cognition are also incorporated to link findings to the naturalistic contexts.

  18. Stimulated growth of coherent VLF waves in the magnetosphere

    International Nuclear Information System (INIS)

    Stiles, G.S.; Helliwell, R.A.

    1977-01-01

    The amplitude behavior of several hundred VLF whistler mode pulse signals and of their associated artificially stimulated emissions (ASE's) was analyzed with digital signal processing techniques. A survey of the results indicates that the pulse signals characteristically show exponential growth with time that is highly repeatable over short periods. However, the growth rate varies widely from time to time, covering a range of 25 to 250 dB/s. During the exponential growth phase of the pulse there is no observable change in frequency. Emissions may begin when growth stops or when the input pulse terminates, whichever occurs first. Low growth rates and falling emissions characterize the beginning and ending of extended periods of emission activity. Rising emissions are prominent at the height of activity. ASE's triggered by station NAA (14.7 kHz, 1 MW radiated) begin when the transmitted Morse dash terminates (dash length, 150 ms). Some ASE's triggered by pulses from Siple Station, Antarctica (1.6 to 7 kHz, < or = to 1 kW), and Omega, New York (10.2 kHz, 100 W), show similar behavior; others, however, begin prior to the termination of the triggering pulse when the pulse length exceeds 200 ms. Growth and frequency change of the ASE tend to be independent of one another. For transmitted pulses of sufficient duration the amplitude saturates prior to termination. Signal amplitudes may reach 30 dB or more above the initial level. During growth the measured bandwidth of the signal remains near the minimum possible (approximately 27 Hz) with the given analysis resolution (approximately 30 ms, approximately 50 Hz). By comparison with mathematical models it is shown that the observed signals have the maximum possible coherence for the measured values of growth rate and duration. These observations are in qualitative agreement with a model that attributes signal growth and ASE's to an interaction between coherent waves and counterstreaming gyroresonant electrons

  19. Frequency dependence of polarization phase difference

    International Nuclear Information System (INIS)

    Rao, K.S.; Rao, Y.S.; Wang, J.R.

    1993-09-01

    Polarimetric AIRSAR data of July 13, 1990 acquired over Mahatango watershed area was processed for the identification of corn fields an forested areas. Polarization Phase Difference (PPD) values were computed for the corn fields at P-, L- and C- bands and studied as a function of frequency. The results compare well with the model calculations at 24 deg. incidence angle where as the locations of corn fields were computed to be at 35 deg. incidence angle. The discrepancy is attributed to lack of accurate ground truth and the undulating topography of the corn fields. Another study reported here deals with the usefulness of Polarization Index (PI) for the study of vegetation. PI was found to be dependent on frequency for corn fields where as for forest trees no such dependence was noticed. PI HH,HV is more useful parameter compared to PI HH,VV even for the study of corn fields. (author). 19 refs, 7 figs

  20. Characteristics of severe thunderstorms studied with the aid of VLF ...

    Indian Academy of Sciences (India)

    oped well calibrated GPS locked software VLF receiver, located at the ... last only a few hours, there is a need to develop .... ally under the joint influence of the South–West .... Meteorological Applications of Lightning Data, San Diego,. CA, Am.

  1. Nonlinear Scattering of VLF Waves in the Radiation Belts

    Science.gov (United States)

    Crabtree, Chris; Rudakov, Leonid; Ganguli, Guru; Mithaiwala, Manish

    2014-10-01

    Electromagnetic VLF waves, such as whistler mode waves, control the lifetime of trapped electrons in the radiation belts by pitch-angle scattering. Since the pitch-angle scattering rate is a strong function of the wave properties, a solid understanding of VLF wave sources and propagation in the magnetosphere is critical to accurately calculate electron lifetimes. Nonlinear scattering (Nonlinear Landau Damping) is a mechanism that can strongly alter VLF wave propagation [Ganguli et al. 2010], primarily by altering the direction of propagation, and has not been accounted for in previous models of radiation belt dynamics. Laboratory results have confirmed the dramatic change in propagation direction when the pump wave has sufficient amplitude to exceed the nonlinear threshold [Tejero et al. 2014]. Recent results show that the threshold for nonlinear scattering can often be met by naturally occurring VLF waves in the magnetosphere, with wave magnetic fields of the order of 50-100 pT inside the plasmapause. Nonlinear scattering can then dramatically alter the macroscopic dynamics of waves in the radiation belts leading to the formation of a long-lasting wave-cavity [Crabtree et al. 2012] and, when amplification is present, a multi-pass amplifier [Ganguli et al. 2012]. By considering these effects, the lifetimes of electrons can be dramatically reduced. This work is supported by the Naval Research Laboratory base program.

  2. Investigation of the receivability of VLF standard time and frequency ...

    African Journals Online (AJOL)

    This study is on the receivability of some standard time and frequency signals in the VLF range in Zaria, Nigeria. Signal field strengths of various stations were estimated, and a suitable radio receiving system was set up to receive them. Using the assembled receiver, some of the transmissions, including the Omega W/L at ...

  3. Spectral characteristics of VLF sferics associated with TGFs

    Science.gov (United States)

    Mezentsev, Andrew; Lehtinen, Nikolai; Ostgaard, Nikolai; Perez-Invernon, Javier; Cummer, Steven

    2017-04-01

    A detailed analysis of RHESSI TGFs is performed in association with WWLLN sources and VLF sferics recorded at Duke University. The analysis of the TGF-WWLLN matches allowed to evaluate RHESSI clock systematic offsets [1], which allows to perform a more precise timing analysis involving TGF data comparisons with the VLF sferics recorded at Duke University. In this work we analyzed the energy spectra of 35 VLF sferics, which were identified as candidates to be emitted by the TGF source, based on the simultaneity and location coincidence between the TGF and radio sources. 20 events have WWLLN detections, which provides a reliable source location of the event. For the other 15 events several selection criteria were used: source location should be consistent with the simultaneity of the TGF and VLF sferic within ±200 μs uncertainty; source location should lay within the azimuthal ±4° cone defined by the ratio of the radial and azimuthal magnetic field components of the VLF sferic; source location should lay within 800 km circle around the RHESSI foot-point; source location should lay within a cluster of a current lightning activity validated by WWLLN (or any other lightning detection network). The energy spectra of 35 VLF sferics related to TGFs were analyzed in the context of the TGF radio emission model developed in [2]. Proposed model represents a TGF at source as a sequence of Np seeding pulses of energetic particles which develop into runaway avalanches in the strong ambient field. These relativistic electrons ionize air along their propagation path which results in secondary currents of low energy electrons and light ions in the ambient electric field. These secondary currents produce radio emissions that can be detected by the ground based sensors. Proposed model allows to express the TGF source current moment energy spectrum using the T50 TGF duration measured by RHESSI. This gives the opportunity to establish and validate empirically the functional link

  4. Sub-ionospheric VLF signal anomaly due to geomagnetic storms: a statistical study

    Directory of Open Access Journals (Sweden)

    K. Tatsuta

    2015-11-01

    Full Text Available We investigate quantitatively the effect of geomagnetic storms on the sub-ionospheric VLF/LF (Very Low Frequency/Low Frequency propagations for different latitudes based on 2-year nighttime data from Japanese VLF/LF observation network. Three statistical parameters such as average signal amplitude, variability of the signal amplitude, and nighttime fluctuation were calculated daily for 2 years for 16–21 independent VLF/LF transmitter–receiver propagation paths consisting of three transmitters and seven receiving stations. These propagation paths are suitable to simultaneously study high-latitude, low-mid-latitude and mid-latitude D/E-region ionospheric properties. We found that these three statistical parameters indicate significant anomalies exceeding at least 2 times of their standard deviation from the mean value during the geomagnetic storm time period in the high-latitude paths with an occurrence rate of anomaly between 40 and 50 % presumably due to the auroral energetic electron precipitation. The mid-latitude and low-mid-latitude paths have a smaller influence from the geomagnetic activity because of a lower occurrence rate of anomalies even during the geomagnetically active time period (from 20 to 30 %. The anomalies except geomagnetic storm periods may be caused by atmospheric and/or lithospheric origins. The statistical occurrence rates of ionospheric anomalies for different latitudinal paths during geomagnetic storm and non-storm time periods are basic and important information not only to identify the space weather effects toward the lower ionosphere depending on the latitudes but also to separate various external physical causes of lower ionospheric disturbances.

  5. A Statistical Study on VLF Subionospheric Perturbations Associated with Major Earthquakes: A View from Focal Mechanism

    Science.gov (United States)

    Kawano, T.; Tatsuta, K.; Hobara, Y.

    2015-12-01

    Continuous monitoring of signal amplitudes of worldwide VLF transmitters is a powerful tool to study the lower ionospheric condition. Although, lower ionospheric perturbations prior to some of the major earthquakes have been reported for years, their occurrence and coupling mechanism between the ground and overlaying ionosphere prior to the earthquakes are not clear yet. In this paper, we carried out a statistical analysis based on the nighttime averaged signal amplitude data from the UEC's VLF/LF transmitter observation network. Two hundred forty three earthquakes were occurred within the 5th Fresnel zone of transmitter-receiver paths around Japan during the time period of 2007 to 2012. These earthquakes were characterized into three different groups based on the Centroid-Moment-Tensor (CMT) solution such as reverse fault type, normal fault type and stress slip type. The ionospheric anomaly was identified by a large change in the VLF/LF amplitude during nighttime. As a result, we found the ionospheric perturbations associated with both ground and sea earthquakes. Remarkably, the reverse fault type earthquakes have the highest occurrence rate of ionospheric perturbation among the three types both for sea (41%) and ground events (61%). The occurrence rates for normal type fault are 35% and 56% for sea and ground earthquakes respectively and the same for stress slip type are 39% and 20% for sea and ground earthquakes respectively. In both cases the occurrence rates are smaller than the reverse fault type. The clear difference of occurrence rate of the ionospheric perturbations may indicate that the coupling efficiency of seismic activity into the overlaying ionosphere is controlled by the pressure in the earth's crust. This gives us further physical insight of Lithosphere-Atmosphere-Ionosphere (LAI) coupling processes.

  6. Massive Statistics of VLF-Induced Ionospheric Disturbances

    Science.gov (United States)

    Pailoor, N.; Cohen, M.; Golkowski, M.

    2017-12-01

    The impact of lightning of the D-region of the ionosphere has been measured by Very Low Frequency (VLF) remote sensing, and can be seen through the observance of Early-Fast events. Previous research has indicated that several factors control the behavior and occurrence of these events, including the transmitter-receiver geometry, as well as the peak current and polarity of the strike. Unfortunately, since each event is unique due to the wide variety of impacting factors, it is difficult to make broad inferences about the interactions between the lightning and ionosphere. By investigating a large database of lightning-induced disturbances over a span of several years and over a continental-scale region, we seek to quantify the relationship between geometry, lightning parameters, and the apparent disturbance of the ionosphere as measured with VLF transmitters. We began with a set of 860,000 cases where an intense lightning stroke above 150 kA occurred within 300 km of a transmiter-receiver path. To then detect ionospheric disturbances from the large volume of VLF data and lightning incidents, we applied a number of classification methods to the actual VLF amplitude data, and find that the most accurate is a convolutional neural network, which yielded a detection efficiency of 95-98%, and a false positive rate less than 25%. Using this model, we were able to assemble a database of more than 97,000 events, with each event stored with its corresponding time, date, receiver, transmitter, and lightning parameters. Estimates for the peak and slope of each disruption were also calculated. From this data, we were able to chart the relationships between geometry and lightning parameters (peak current and polarity) towards the occurrence probability, perturbation intensity, and recovery time, of the VLF perturbation. The results of this analysis are presented here.

  7. On the observations of unique low latitude whistler-triggered VLF/ELF emissions

    Science.gov (United States)

    Altaf, M.; Singh, K. K.; Singh, A. K.; Lalmani

    A detailed analysis of the VLF/ELF wave data obtained during a whistler campaign under All India Coordinated Program of Ionosphere Thermosphere Studies (AICPITS) at our low latitude Indian ground station Jammu (geomag. lat. = 22° 26‧ N, L = 1.17) has yielded two types of unusual and unique whistler-triggered VLF/ELF emissions. These include (1) whistler-triggered hook emissions and (2) whistler-triggered long enduring discrete chorus riser emissions in VLF/ELF frequency range during night time. Such types of whistler-triggered emissions have not been reported earlier from any of the ground observations at low latitudes. In the present study, the observed characteristics of these emissions are described and interpreted. Dispersion analysis of these emissions show that the whistlers as well as emissions have propagated along a higher geomagnetic field line path with L-values lying ∼L = 4, suggesting that these triggered emissions are to be regarded as mid-latitude emissions. These waves could have propagated along the geomagnetic field lines either in a ducted mode or in a pro-longitudinal (PL) mode. The measured intensity of the triggered emissions is almost equal to that of the source waves and does not vary throughout the period of observation on that day. It is speculated that these emissions may have been generated through a process of resonant interaction of the whistler waves with energetic electrons. Parameters related to this interaction are computed for different values of L and wave amplitude. The proposed mechanism explains some aspects of the dynamic spectra.

  8. Some unusual discrete VLF emissions observed at a low-latitude ground station at Agra

    Directory of Open Access Journals (Sweden)

    B. Singh

    Full Text Available A detailed analysis of the VLF emissions data obtained during occasional whistler campaigns at the low-latitude ground station Agra (geomagnetic latitude 17°1' N, L = 1.15 has yielded some unusual discrete VLF emissions of the rising type. These include (1 emissions occurring at time intervals increasing in ge ommetrical progression, (2 emissions occuring simulta neously in different frequency ranges and (3 emissions observed during daytime. In the present study, the observed characteristics of these emissions are described and interpreted. It is shown that the increasing time delay between different components of the emissions match closely with the propagation time delays between different hops of a whistler of dispersion 19 s1/2, the unusual occurrence of the emissions in two different frequency ranges approximately at the same time may possibly be linked with their generation at two different locations, and the occurrence of emissions during daytime may be due to propagation under the influence of equatorial anomaly.

  9. Some unusual discrete VLF emissions observed at a low-latitude ground station at Agra

    Directory of Open Access Journals (Sweden)

    B. Singh

    1997-08-01

    Full Text Available A detailed analysis of the VLF emissions data obtained during occasional whistler campaigns at the low-latitude ground station Agra (geomagnetic latitude 17°1' N, L = 1.15 has yielded some unusual discrete VLF emissions of the rising type. These include (1 emissions occurring at time intervals increasing in ge ommetrical progression, (2 emissions occuring simulta neously in different frequency ranges and (3 emissions observed during daytime. In the present study, the observed characteristics of these emissions are described and interpreted. It is shown that the increasing time delay between different components of the emissions match closely with the propagation time delays between different hops of a whistler of dispersion 19 s1/2, the unusual occurrence of the emissions in two different frequency ranges approximately at the same time may possibly be linked with their generation at two different locations, and the occurrence of emissions during daytime may be due to propagation under the influence of equatorial anomaly.

  10. Subionospheric VLF signatures of nighttime D region perturbations in the vicinity of lightning discharges

    International Nuclear Information System (INIS)

    Inan, U.S.; Shafer, D.C.; Yip, W.Y.; Orville, R.E.

    1988-01-01

    A 12-hour sequence of perturbations of subionospheric VLF signals observed in association with lightning provided preliminary evidence that the ionospheric regions perturbed in these events may be confined to within ∼ 150 km of the lightning discharges, and that intracloud flashes as well as cloud-to-ground lightning may be important in producing the perturbations. High-resolution analysis of event signatures indicated the presence of two different classes of events. For one set of events, observed during the most active central 6 hours of the observations period, a ∼ 0.6-s delay between the causative lightning and VLF event onset and a ∼ 1-s onset duration was observed, consistent with previously suggested models of the gyroresonant whistler-paritcle interaction that leads to particle precipitation and perturbation of the Earth-ionosphere waveguide. However, another set of events, observed during the first 2 hours of the observation period, exhibited a very different temporal signature, characterized by a much smaller (<50 ms) delay and sometimes also very short (< 50 ms) rise times. Such events are possibly related to previously reported cases of similarly early/fast events and may involve a more direct coupling between the lightning discharge and the lower ionosphere

  11. More evidence for a one-to-one correlation between Sprites and Early VLF perturbations

    DEFF Research Database (Denmark)

    Haldoupis, C.; Amvrosiadi, N.; Cotts, B. R. T.

    2010-01-01

    Past studies have shown a correlation between sprites and early VLF perturbations, but the reported correlation varies widely from ∼50% to 100%. The present study resolves these large discrepancies by analyzing several case studies of sprite and narrowband VLF observations, in which multiple...... VLF events. However, the one‐to‐one visible sprite to early VLF event correspondence, if viewed conversely, appears not to be always reciprocal. This is because the number of early events detected in some case studies was considerably larger than the number of visible sprites. Since the great majority...

  12. Calculated optical absorption of different perovskite phases

    Energy Technology Data Exchange (ETDEWEB)

    Castelli, Ivano E. [Center for Atomic-scale Materials Design; Department of Physics; Technical University of Denmark; DK 2800, Kongens Lyngby; Denmark; Thygesen, Kristian S. [Center for Atomic-scale Materials Design; Department of Physics; Technical University of Denmark; DK 2800, Kongens Lyngby; Denmark; Jacobsen, Karsten W. [Center for Atomic-scale Materials Design; Department of Physics; Technical University of Denmark; DK 2800, Kongens Lyngby; Denmark

    2015-01-01

    We present calculations of the optical properties of a set of around 80 oxides, oxynitrides, and organometal halide cubic and layered perovskites (Ruddlesden–Popper and Dion–Jacobson phases) with a bandgap in the visible part of the solar spectrum.

  13. New type of ensemble of quasi-periodic, long-lasting VLF emissions at the auroral zone

    Directory of Open Access Journals (Sweden)

    J. Manninen

    2012-12-01

    Full Text Available A new type of the series of quasi-periodic (QP very low frequency (VLF emissions in frequency range of 1–5 kHz, and not associated with geomagnetic pulsations, has been discovered at auroral latitudes (L = 5.3 during the Finnish VLF campaign (held in December 2011. At least five unusually spectacular events, each with a duration of several hours, have been observed during the night under conditions of quiet geomagnetic activity (Kp = 0–1, although QPs usually occur during the daytime. Contrary to the QP emissions typically occurring during the day, the spectral structure of these QP events represented an extended, complicated sequence of repeated discrete rising VLF signals. Their duration was about 2–3 min each, with the repetition periods ranging from ~1 min to ~10 min. Two such nighttime non-typical events are reported in this paper. The fine structure of the separated QP elements may represent a mixture of the different frequency band signals, which seem to have independent origins. It was found that the periodic signals with lower frequency appear to trigger the strong dispersive upper frequency signals. The temporal dynamics of the spectral structure of the QPs studied were significantly controlled by some disturbances in the solar wind and interplanetary magnetic field (IMF. This finding is very important for future theoretical investigations because the generation mechanism of this new type of QP emissions is not yet understood.

  14. Combined VLF and VHF lightning observations of Hurricane Rita landfall

    Science.gov (United States)

    Henderson, B. G.; Suszcynsky, D. M.; Wiens, K. C.; Hamlin, T.; Jeffery, C. A.; Orville, R. E.

    2009-12-01

    Hurricane Rita displayed abundant lightning in its northern eyewall as it made landfall at 0740 UTC 24 Sep 2005 near the Texas/Louisiana border. For this work, we combined VHF and VLF lightning data from Hurricane Rita, along with radar observations from Gulf Coast WSR-88D stations, for the purpose of demonstrating the combined utility of these two spectral regions for hurricane lightning monitoring. Lightning is a direct consequence of the electrification and breakdown processes that take place during the convective stages of thunderstorm development. As Rita approached the Gulf coast, the VHF lightning emissions were distinctly periodic with a period of 1.5 to 2 hours, which is consistent with the rotational period of hurricanes. VLF lightning emissions, measured by LASA and NLDN, were present in some of these VHF bursts but not all of them. At landfall, there was a significant increase in lightning emissions, accompanied by a significant convective surge observed in radar. Furthermore, VLF and VHF lightning source heights clearly increase as a function of time. The evolution of the IC/CG ratio is consistent with that seen in thunderstorms, showing a dominance of IC activity during storm development, followed by an increase in CG activity at the storm’s peak. The periodic VHF lightning events are correlated with increases in convective growth (quantified by the volume of radar echo >40 dB) above 7 km altitude. VLF can discriminate between lightning types, and in the LASA data, Rita landfall lightning activity was dominated by Narrow Bi-polar Events (NBEs)—high-energy, high-altitude, compact intra-cloud discharges. The opportunity to locate NBE lightning sources in altitude may be particularly useful in quantifying the vertical extent (strength) of the convective development and in possibly deducing vertical charge distributions.

  15. Trapped electron losses by interactions with coherent VLF waves

    International Nuclear Information System (INIS)

    Walt, M.; Inan, U.S.; Voss, H.D.

    1996-01-01

    VLF whistler waves from lightning enter the magnetosphere and cause the precipitation of energetic trapped electrons by pitch angle scattering. These events, known as Lightning-induced Electron Precipitation (LEP) have been detected by satellite and rocket instruments and by perturbations of VLF waves traveling in the earth-ionosphere waveguide. Detailed comparison of precipitating electron energy spectra and time dependence are in general agreement with calculations of trapped electron interactions with ducted whistler waves. In particular the temporal structure of the precipitation and the dynamic energy spectra of the electrons confirm this interpretation of the phenomena. There are discrepancies between observed and measured electron flux intensities and pitch angle distributions, but these quantities are sensitive to unknown wave intensities and trapped particle fluxes near the loss cone angle. The overall effect of lightning generated VLF waves on the lifetime of trapped electrons is still uncertain. The flux of electrons deflected into the bounce loss cone by a discrete whistler wave has been measured in a few cases. However, the area of the precipitation region is not known, and thus the total number of electrons lost in an LEP event can only be estimated. While the LEP events are dramatic, more important effects on trapped electrons may arise from the small but numerous deflections which increase the pitch angle diffusion rate of the electron population. copyright 1996 American Institute of Physics

  16. Trapped electron losses by interactions with coherent VLF waves

    Science.gov (United States)

    Walt, M.; Inan, U. S.; Voss, H. D.

    1996-07-01

    VLF whistler waves from lightning enter the magnetosphere and cause the precipitation of energetic trapped electrons by pitch angle scattering. These events, known as Lightning-induced Electron Precipitation (LEP) have been detected by satellite and rocket instruments and by perturbations of VLF waves traveling in the earth-ionosphere waveguide. Detailed comparison of precipitating electron energy spectra and time dependence are in general agreement with calculations of trapped electron interactions with ducted whistler waves. In particular the temporal structure of the precipitation and the dynamic energy spectra of the electrons confirm this interpretation of the phenomena. There are discrepancies between observed and measured electron flux intensities and pitch angle distributions, but these quantities are sensitive to unknown wave intensities and trapped particle fluxes near the loss cone angle. The overall effect of lightning generated VLF waves on the lifetime of trapped electrons is still uncertain. The flux of electrons deflected into the bounce loss cone by a discrete whistler wave has been measured in a few cases. However, the area of the precipitation region is not known, and thus the total number of electrons lost in an LEP event can only be estimated. While the LEP events are dramatic, more important effects on trapped electrons may arise from the small but numerous deflections which increase the pitch angle diffusion rate of the electron population.

  17. Airborne VLF survey of Izu-Oshima volcano

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Yutaka; Yukutake, Takeshi

    1988-05-17

    Resistivity distribution in underground indicates anomaly in some cases due to volcanic activity, airborne VLF survey of Izu-Oshima volcano in whole area was carried out by measurement of the anomalous vertical magnetic field. The flight direction was determined with reference to both of the transmitter direction of the VLF waves and the running direction of the geologic formation. The flight altitude and the flight lines spacing were 100 m and 200 m respectively. Typical profiles of four lines of measurement were investigated. The resistivity anomalies were indicated corresponding to the position of known geologic fissure line, the lip of the caldera, the line of the craters and side volcanos. Several anomalous trends were detected by the contour drawing of the Fraser filter output. The detected results were as follow: new volcanos with the resistivity anomaly, the resistivity anomalies spread to the north-northwest from Goshinka jaya, the anomalies due to flowed lava, the anomalies by encroached water from the caldera wall, the effects from side volcanoes and so on. The resistivity anomalies by airborne VLF survey correspond to the known volcanic activities, and they are useful for elucidation of the underground volcanism. (6 figs, 4 refs)

  18. Metrology of two-phase flow: different methods

    International Nuclear Information System (INIS)

    Delhaye, J.M.; Galaup, J.P.; Reocreux, M.; Ricque, R.

    Nine papers are presented concerning different methods of measuring two-phase flow. Some of the methods and equipment discussed include: radiation absorption, electromagnetic flowmeter, anemometry, resistance probes, phase indicating microthermocouples, optical probes, sampling methods, and pitot tubes

  19. Modeling of very low frequency (VLF radio wave signal profile due to solar flares using the GEANT4 Monte Carlo simulation coupled with ionospheric chemistry

    Directory of Open Access Journals (Sweden)

    S. Palit

    2013-09-01

    Full Text Available X-ray photons emitted during solar flares cause ionization in the lower ionosphere (~60 to 100 km in excess of what is expected to occur due to a quiet sun. Very low frequency (VLF radio wave signals reflected from the D-region of the ionosphere are affected by this excess ionization. In this paper, we reproduce the deviation in VLF signal strength during solar flares by numerical modeling. We use GEANT4 Monte Carlo simulation code to compute the rate of ionization due to a M-class flare and a X-class flare. The output of the simulation is then used in a simplified ionospheric chemistry model to calculate the time variation of electron density at different altitudes in the D-region of the ionosphere. The resulting electron density variation profile is then self-consistently used in the LWPC code to obtain the time variation of the change in VLF signal. We did the modeling of the VLF signal along the NWC (Australia to IERC/ICSP (India propagation path and compared the results with observations. The agreement is found to be very satisfactory.

  20. Detection of Nonverbal Synchronization through Phase Difference in Human Communication.

    Science.gov (United States)

    Kwon, Jinhwan; Ogawa, Ken-ichiro; Ono, Eisuke; Miyake, Yoshihiro

    2015-01-01

    Nonverbal communication is an important factor in human communication, and body movement synchronization in particular is an important part of nonverbal communication. Some researchers have analyzed body movement synchronization by focusing on changes in the amplitude of body movements. However, the definition of "body movement synchronization" is still unclear. From a theoretical viewpoint, phase difference is the most important factor in synchronization analysis. Therefore, there is a need to measure the synchronization of body movements using phase difference. The purpose of this study was to provide a quantitative definition of the phase difference distribution for detecting body movement synchronization in human communication. The phase difference distribution was characterized using four statistical measurements: density, mean phase difference, standard deviation (SD) and kurtosis. To confirm the effectiveness of our definition, we applied it to human communication in which the roles of speaker and listener were defined. Specifically, we examined the difference in the phase difference distribution between two different communication situations: face-to-face communication with visual interaction and remote communication with unidirectional visual perception. Participant pairs performed a task supposing lecture in the face-to-face communication condition and in the remote communication condition via television. Throughout the lecture task, we extracted a set of phase differences from the time-series data of the acceleration norm of head nodding motions between two participants. Statistical analyses of the phase difference distribution revealed the characteristics of head nodding synchronization. Although the mean phase differences in synchronized head nods did not differ significantly between the conditions, there were significant differences in the densities, the SDs and the kurtoses of the phase difference distributions of synchronized head nods. These

  1. Detection of Nonverbal Synchronization through Phase Difference in Human Communication.

    Directory of Open Access Journals (Sweden)

    Jinhwan Kwon

    Full Text Available Nonverbal communication is an important factor in human communication, and body movement synchronization in particular is an important part of nonverbal communication. Some researchers have analyzed body movement synchronization by focusing on changes in the amplitude of body movements. However, the definition of "body movement synchronization" is still unclear. From a theoretical viewpoint, phase difference is the most important factor in synchronization analysis. Therefore, there is a need to measure the synchronization of body movements using phase difference. The purpose of this study was to provide a quantitative definition of the phase difference distribution for detecting body movement synchronization in human communication. The phase difference distribution was characterized using four statistical measurements: density, mean phase difference, standard deviation (SD and kurtosis. To confirm the effectiveness of our definition, we applied it to human communication in which the roles of speaker and listener were defined. Specifically, we examined the difference in the phase difference distribution between two different communication situations: face-to-face communication with visual interaction and remote communication with unidirectional visual perception. Participant pairs performed a task supposing lecture in the face-to-face communication condition and in the remote communication condition via television. Throughout the lecture task, we extracted a set of phase differences from the time-series data of the acceleration norm of head nodding motions between two participants. Statistical analyses of the phase difference distribution revealed the characteristics of head nodding synchronization. Although the mean phase differences in synchronized head nods did not differ significantly between the conditions, there were significant differences in the densities, the SDs and the kurtoses of the phase difference distributions of synchronized head

  2. Subionospheric VLF/LF radio waves propagation characteristics before, during and after the Sofia, Bulgaria Mw=5.6 earthquake occurred on 22 May 2012

    Science.gov (United States)

    Moldovan, Iren Adelina; Emilian Toader, Victorin; Nenovski, Petko; Biagi, Pier Francesco; Maggipinto, Tommaso; Septimiu Moldovan, Adrian; Ionescu, Constantin

    2013-04-01

    In 2009, INFREP, a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers, was put into operation in Europe having as principal goal, the study of disturbances produced by the earthquakes on the propagation properties of these signals. On May 22nd, 2012 an earthquake with Mw=567 occurred in Bulgaria, near Sofia, inside the "sensitive" area of the INFREP VLF/LF electromagnetic network. The data collected on different frequencies, during April-May 2012 were studied using different methods of analysis: daily correlation methods, spectral approaches and terminator time techniques, in order to find out possible connections between the seismic activity and the subionospheric propagation properties of radio waves. The studies were performed with the help of a specially designed LabVIEW application, which accesses the VLF/LF receiver through internet. This program opens the receiver's web-page and automatically retrieves the list of data files to synchronize the user-side data with the receiver's data. Missing zipped files are also automatically downloaded. The application performs primary, statistical correlation and spectral analysis, appends daily files into monthly and annual files and performs 3D colour-coded maps with graphic representations of VLF and LF signals' intensities versus the minute-of-the-day and the day-of-the-month, facilitating a near real-time observation of VLF and LF electromagnetic waves' propagation. Another feature of the software is the correlation of the daily recorded files for the studied frequencies by overlaying the 24 hours radio activity and taking into account the sunrise and sunset. Data are individually processed (spectral power, correlations, differentiation, filtered using bandpass, lowpass, highpass). JTFA spectrograms (Cone-Shaped Distribution CSD, Gabor, Wavelet, short-time Fourier transform STFT, Wigner-Ville Distribution WVD, Choi-Williams Distribution CWD) are used, too.

  3. The VLF fingerprint of elves: Step-like and long-recovery early VLF perturbations caused by powerful ±CG lightning EM pulses

    Science.gov (United States)

    Haldoupis, Christos; Cohen, Morris; Arnone, Enrico; Cotts, Benjamin; Dietrich, Stefano

    2013-08-01

    Subionospheric VLF recordings are investigated in relation with intense cloud-to-ground (CG) lightning data. Lightning impacts the lower ionosphere via heating and ionization changes which produce VLF signal perturbations known as early VLF events. Typically, early events recover in about 100 s, but a small subclass does not recover for many minutes, known as long-recovery early events (LORE). In this study, we identify LORE as a distinct category of early VLF events, whose signature may occur either on its own or alongside the short-lived typical early VLF event. Since LORE onsets coincide with powerful lightning strokes of either polarity (±), we infer that they are due to long-lasting ionization changes in the uppermost D region ionosphere caused by electromagnetic pulses emitted by strong ± CG lightning peak currents of typically > 250 kA, which are also known to generate elves. The LORE perturbations are detected when the discharge is located within ~250 km from the great circle path of a VLF transmitter-receiver link. The probability of occurrence increases with stroke intensity and approaches unity for discharges with peak currents ≥ ~300 kA. LOREs are nighttime phenomena that occur preferentially, at least in the present regional data set, during winter when strong ± CG discharges are more frequent and intense. The evidence suggests LORE as a distinct signature representing the VLF fingerprint of elves, a fact which, although was predicted by theory, it escaped identification in the long-going VLF research of lightning effects in the lower ionosphere.

  4. Quasi-static electric fields, turbulence and VLF waves in the ionosphere and magnetosphere

    International Nuclear Information System (INIS)

    Temerin, M.A.

    1978-01-01

    Two rocket payloads launched from Greenland in December 1974 and January 1975 into the dayside auroral oval measured large scale electric fields. Sunward convection in regions of polar cusp type particle precipitation argues for the existence of a turbulent entry region at the magnetopause. Smaller scale changes in the electric field and energetic electron precipitation require field-aligned currents predominately at the boundaries of auroral arcs. Measurements of electric fields parallel to the magnetic field place upper limits to the parallel electric field. An analysis of the effect of zero-frequency electric field turbulence on the output of an electric field double probe detector is applied to data from two satellites, OVI-17 and S3-3. It is found that the electric field of high latitude low frequency turbulence is polarized perpendicular to the magnetic field and that the frequency is measured by the satellites is due to the Doppler shift of near zero frequency turbulence both in the ionosphere and magnetosphere. In addition, rocket measurements of low frequency turbulence in the dayside auroral oval reveal characteristics similar to those of the large electric field regions recently seen on S3-3 indicating that the turbulence from those regions extends into the ionosphere. VLF waves were also observed during the two rocket flights into the dayside auroral oval. The correlation of the VLF hiss intensity with the fluxes of precipitating electrons above 500 eV on a short spatial and time scale is often poor, even when a positive slope exists in the electron phase space density. The frequency of the lower hybrid waves were used to measure the ratio of NO + and O 2 + to O + . Electrostatic waves were observed during a barium release

  5. Modification of the ionosphere by VLF wave-induced electron precipitation

    International Nuclear Information System (INIS)

    Doolittle, J.H.

    1982-01-01

    Very low frequency (VLF) waves propagating in the whistler mode in the magnetosphere are known to cause precipitation of energetic electrons at middle latitudes. The interactions between the waves and electrons trapped in the magnetic field are believed to occur through cyclotron resonance. As a monochromatic wave propagates along a field line, the condition for resonance can be satisfied by electrons of a minimum energy at the equator and higher energies at increasing latitudes. Resonant interactions occurring in a field aligned region extending several thousand kilometers on both sides of the equator can therefore result in a precipitation flux with a wide range of energies. Electrons which are scattered into the loss cone will collide with the constituents of the ionosphere, causing additional ionization optical emissions, x-rays and heating. A computational technique is introduced which allows the temporal shape of pulse of precipitation to be modeled. A realistic energy distribution is used to weigh the contribution to the total precipitation energy flux resulting from resonant interactions in each segment of the duct. Wave growth along the path is found to affect the shape of the pulse. In its simplest application, the model sets limits on the time window in which a precipitation event can occur. The model arrival times are shown to agree with experimental correlations of VLF waves and effects of precipitation occurring on three occasions, thus supporting the assumption, that the precipitation results from cyclotron resonant scattering. Various techniques that have been employed for detecting wave-induced precipitation are compared. A quantitative analysis of the use of an HF radar for this purpose is introduced, based on the changes in the phase and group paths of the radar signals that are reflected from the perturbed ionosphere

  6. VLF emissions in the Venus foreshock - Comparison with terrestrial observations

    Science.gov (United States)

    Crawford, G. K.; Strangeway, R. J.; Russell, C. T.

    1993-01-01

    An examination is conducted of ELF/VLF emissions observed in the solar wind upstream of the Venus shock, for the 100 Hz-30 kHz range, using data from the Pioneer Venus Orbiter's electric field detector and magnetometer instruments. Detailed comparisons are made with terrestrial measurements for both the electron and ion foreshocks. The results obtained support the Crawford et al. (1990) identification of the Venus electron foreshock emissions as electron plasma oscillations, whose waves are generated in situ and act to isotropize the electron distributions.

  7. Chaos crisis in coupled Duffing's systems with initial phase difference

    International Nuclear Information System (INIS)

    Bi Qinsheng

    2007-01-01

    The dynamics of coupled Duffing's oscillators with initial phase difference is investigated in this Letter. For the averaged equations, different equilibrium points can be observed, the number of which may vary with the parameters. The stable equilibrium points, corresponding to the periodic motion of the original coupled oscillators, may coexist with different patterns of dynamics, including chaos. Furthermore, two different chaotic attractors associated with different attracting basin coexist for certain parameter conditions, which may interact with each other to form an enlarged chaotic attractor. Several new dynamical phenomena such as boundary chaos crises have been predicted as the initial phase difference varies

  8. Electric and VLF-MT survey of Tegatayama tunnel; Tegatayama tunnel no denki tansa oyobi VLF tansa

    Energy Technology Data Exchange (ETDEWEB)

    Nishitani, T [Akita University, Akita (Japan). Mining College

    1997-05-27

    To survey the structure at the depth between 20 and 30 m, field tests were conducted by means of vertical electric and VFL-MT (magnetotelluric) survey. Tegatayama tunnel has a total length of 276 m, width of 7.5 m, and height of 4.7 m, and the depth from the surface is about 28 m near the top of mountain. Near the tunnel, the thickness of surface soil is about 60 cm, which consists of clay soil including soft mudstone gravel. It was found that terrace deposit is distributed up to the depth of 8 m, and that mudstone is distributed below the depth of 8 m. Weighted four-electrode method was adopted for the vertical electrical survey. Measurements were conducted at the immediately above the tunnel, 10 m apart from the center of tunnel in the right and left, and 20 m apart from the center in the east. For the VLF-MT method, component of frequency 22.2 kHz was used. As a result of the tests, it was difficult to illustrate the existence of tunnel from the vertical electrical survey only at one point. Feature of the tunnel could be well illustrated by means of the VLF-MT method. 3 refs., 9 figs.

  9. Nonlinear VLF Wave Physics in the Radiation Belts

    Science.gov (United States)

    Crabtree, C. E.; Tejero, E. M.; Ganguli, G.; Mithaiwala, M.; Rudakov, L.; Hospodarsky, G. B.; Kletzing, C.

    2014-12-01

    Electromagnetic VLF waves, such as whistler mode waves, both control the lifetime of trapped electrons in the radiation belts by pitch-angle scattering and are responsible for the energization of electrons during storms. Traditional approaches to understanding the influence of waves on trapped electrons have assumed that the wave characteristics (frequency spectrum, wave-normal angle distribution, etc.) were both stationary in time and amplitude independent from event to event. In situ data from modern satellite missions, such as the Van Allen probes, are showing that this assumption may not be justified. In addition, recent theoretical results [Crabtree et al. 2012] show that the threshold for nonlinear wave scattering can often be met by naturally occurring VLF waves in the magnetosphere, with wave magnetic fields of the order of 50-100 pT inside the plasmapause. Nonlinear wave scattering (Nonlinear Landau Damping) is an amplitude dependent mechanism that can strongly alter VLF wave propagation [Ganguli et al. 2010], primarily by altering the direction of propagation. Laboratory results have confirmed the dramatic change in propagation direction when the pump wave has sufficient amplitude to exceed the nonlinear threshold [Tejero et al. 2014]. Nonlinear scattering can alter the macroscopic dynamics of waves in the radiation belts leading to the formation of a long-lasting wave-cavity [Crabtree et al. 2012] and, when amplification is present, a multi-pass amplifier [Ganguli et al., 2012]. Such nonlinear wave effects can dramatically reduce electron lifetimes. Nonlinear wave dynamics such as these occur when there are more than one wave present, such a condition necessarily violates the assumption of traditional wave-normal analysis [Santolik et al., 2003] which rely on the plane wave assumption. To investigate nonlinear wave dynamics using modern in situ data we apply the maximum entropy method [Skilling and Bryan, 1984] to solve for the wave distribution function

  10. VLF Cutler: September 1997 Four-Panel Tests; RADHAZ and Field Strength Measurement

    National Research Council Canada - National Science Library

    Hansen, P

    1998-01-01

    The objective of the four panel tests was to provide VLF Cutler with the capability of performing the special painting project and normal maintenance on the bow tie area towers of an inactive array...

  11. VLF/LF Radio Sounding of Ionospheric Perturbations Associated with Earthquakes

    Directory of Open Access Journals (Sweden)

    Masashi Hayakawa

    2007-07-01

    Full Text Available It is recently recognized that the ionosphere is very sensitive to seismic effects,and the detection of ionospheric perturbations associated with earthquakes, seems to bevery promising for short-term earthquake prediction. We have proposed a possible use ofVLF/LF (very low frequency (3-30 kHz /low frequency (30-300 kHz radio sounding ofthe seismo-ionospheric perturbations. A brief history of the use of subionospheric VLF/LFpropagation for the short-term earthquake prediction is given, followed by a significantfinding of ionospheric perturbation for the Kobe earthquake in 1995. After showingprevious VLF/LF results, we present the latest VLF/LF findings; One is the statisticalcorrelation of the ionospheric perturbation with earthquakes and the second is a case studyfor the Sumatra earthquake in December, 2004, indicating the spatical scale and dynamicsof ionospheric perturbation for this earthquake.

  12. Intensity fluctuations of mid-latitude background VLF-noises and the interplanetary magnetic field

    International Nuclear Information System (INIS)

    Gorshkov, Yu.N.; Klejmenova, N.G.

    1986-01-01

    Influence of interplanetary magnetic field (IMF) sector structure polarity and also variations of solar wind velocity and density on the intensity of mid-latitude VLF background noises are studied. For analysis continuous observations of VLF radiations in Magadan Observatory (phi=53.7 deg, L=2.7) from November, 1972 to June, 1973 were used. It is shown that IMF sector sign has no sufficient effect on the level of mid-latitude VLF background noises at the frequences f < 4-5 kHz. In magnetoperturbed periods when IMF Bsub(z)-component was directed to the South and the Earth was in the region of high-speed plasma flux, in mid-latitudes abatement of intensity of VLF background noises was seen

  13. Excitation of the Magnetospheric Cavity by Space-Based ELF/VLF Transmitters

    National Research Council Canada - National Science Library

    Bell, Timothy F; Inan, Umran; Kulkarni, P

    2004-01-01

    During the period of performance Stanford University: 1. Developed an analytical model describing the distribution of current along a dipole antenna radiating ELF/VLF waves in the magnetospheric cavity...

  14. More evidence for a one-to-one correlation between Sprites and Early VLF perturbations

    Science.gov (United States)

    Haldoupis, C.; Amvrosiadi, N.; Cotts, B. R. T.; van der Velde, O. A.; Chanrion, O.; Neubert, T.

    2010-07-01

    Past studies have shown a correlation between sprites and early VLF perturbations, but the reported correlation varies widely from ˜50% to 100%. The present study resolves these large discrepancies by analyzing several case studies of sprite and narrowband VLF observations, in which multiple transmitter-receiver VLF pairs with great circle paths (GCPs) passing near a sprite-producing thunderstorm were available. In this setup, the multiple paths act in a complementary way that makes the detection of early VLF perturbations much more probable compared to a single VLF path that can miss several of them, a fact that was overlooked in past studies. The evidence shows that visible sprite occurrences are accompanied by early VLF perturbations in a one-to-one correspondence. This implies that the sprite generation mechanism may cause also sub-ionospheric conductivity disturbances that produce early VLF events. However, the one-to-one visible sprite to early VLF event correspondence, if viewed conversely, appears not to be always reciprocal. This is because the number of early events detected in some case studies was considerably larger than the number of visible sprites. Since the great majority of the early events not accompanied by visible sprites appeared to be caused by positive cloud to ground (+CG) lightning discharges, it is possible that sprites or sprite halos were concurrently present in these events as well but were missed by the sprite-watch camera detection system. In order for this option to be resolved we need more studies using highly sensitive optical systems capable of detecting weaker sprites, sprite halos and elves.

  15. VLF observations of ionospheric disturbances in association with TLEs from the EuroSprite-2007 campaign

    DEFF Research Database (Denmark)

    NaitAmor, S.; AlAbdoadaim, M. A.; Cohen, M. B.

    2010-01-01

    ) were captured over the Mediterranean Sea by cameras at Pic du Midi (42.94°N, 0.14°E) and at Centre de Recherches Atmospheriques (CRA) in southwestern France (43.13°N, 0.37°E). The cameras observations are compared to collected VLF AWESOME data. We consider early VLF perturbations observed on 12-13, 17...

  16. Characteristic and Wigner function for number difference and operational phase

    International Nuclear Information System (INIS)

    Fan Hongyi; Hu Haipeng

    2004-01-01

    We introduce the characteristic function in the sense of number difference-operational phase, and we employ the correlated-amplitude-number-difference state representation to calculate it. It results in the form of the corresponding Wigner function and Wigner operator. The marginal distributions of the generalized Wigner function are briefly discussed

  17. A survey of ELF and VLF research on lightning-ionosphere interactions and causative discharges

    Science.gov (United States)

    Inan, U. S.; Cummer, S. A.; Marshall, R. A.

    2010-06-01

    Extremely low frequency (ELF) and very low frequency (VLF) observations have formed the cornerstone of measurement and interpretation of effects of lightning discharges on the overlying upper atmospheric regions, as well as near-Earth space. ELF (0.3-3 kHz) and VLF (3-30 kHz) wave energy released by lightning discharges is often the agent of modification of the lower ionospheric medium that results in the conductivity changes and the excitation of optical emissions that constitute transient luminous events (TLEs). In addition, the resultant ionospheric changes are best (and often uniquely) observable as perturbations of subionospherically propagating VLF signals. In fact, some of the earliest evidence for direct disturbances of the lower ionosphere in association with lightning discharges was obtained in the course of the study of such VLF perturbations. Measurements of the detailed ELF and VLF waveforms of parent lightning discharges that produce TLEs and terrestrial gamma ray flashes (TGFs) have also been very fruitful, often revealing properties of such discharges that maximize ionospheric effects, such as generation of intense electromagnetic pulses (EMPs) or removal of large quantities of charge. In this paper, we provide a review of the development of ELF and VLF measurements, both from a historical point of view and from the point of view of their relationship to optical and other observations of ionospheric effects of lightning discharges.

  18. Broadband phase difference method for ultrasonic velocimetry in molten glass

    International Nuclear Information System (INIS)

    Kikura, Hiroshige; Ihara, Tomonori

    2016-01-01

    This study aims to develop ultrasonic Doppler velocimetry in molten glass. Realization of such a technique has two difficulties: ultrasonic transmission into molten salt and Doppler signal processing. Buffer rod technique was developed in our research to transmit ultrasound into high temperature molten glass. This article discusses newly developed signal processing technique named broadband phase difference method. (J.P.N.)

  19. Remark on Relations Between Different Non-integrable Phases

    International Nuclear Information System (INIS)

    Gu Zhiyu; Qian Shangwu

    2005-01-01

    There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the definitions and relations between these three non-integrable phases.

  20. VLF radio wave anomalies associated with the 2010 Ms 7.1 Yushu earthquake

    Science.gov (United States)

    Shen, Xuhui; Zhima, Zeren; Zhao, Shufan; Qian, Geng; Ye, Qing; Ruzhin, Yuri

    2017-05-01

    The VLF radio signals recorded both from the ground based VLF radio wave monitoring network and the DEMETER satellite are investigated during the 2010 Ms 7.1 Yushu earthquake. The ground-based observations show that the disturbance intensity of VLF wave's amplitude relative to the background gets an enhancement over 22% at 11.9 kHz, 27% at 12.6 kHz and 62% at 14.9 kHz VLF radio wave along the path from Novosibirsk - TH one day before the main shock, as compared to the maximum 20% observed during non-earthquake time. The space based observations indicate that there is a decrease of the signal to noise ratio (SNR) for the power spectral density data of 14.9 kHz VLF radio signal at electric field four days before the main shock, with disturbance intensity exceeding the background by over 5% as compared to the maximum 3% observed during non-earthquake time. The geoelectric field observations in the epicenter region also show that a sharp enhancement from ∼340 to 430 mV/km simultaneously appeared at two monitors 14 days before main shock. The comparative analysis from the ground and space based observations during the earthquake and non-earthquake time provides us convincible evidence that there exits seismic anomalies from the VLF radio wave propagation before the 2010 Ms 7.1 Yushu earthquake. The possible mechanism for VLF radio signal propagation anomaly during 2010 Yushu earthquake maybe related to the change of the geoelectric field nearby the earthquake zone.

  1. Pulsed cathodoluminescence of nanoscale aluminum oxide with different phase compositions

    International Nuclear Information System (INIS)

    Kortov, V.S.; Zvonarev, S.V.; Medvedev, A.I.

    2011-01-01

    The methods of pulsed cathodoluminescence have been used to study compacted powders and ceramics containing different phases of aluminum oxide. An intensive luminescence of the samples under study in the visible, NIR, and UV regions of the spectrum has been found. The luminescence bands are very broad and include a few components. The number of the bands depends on the phase composition of the samples. The oxygen vacancies, which capture one or two electrons, produce luminescence centers in the near UV region. The most probable in the visible region is the luminescence of aggregate defects, impurities, and surface centers. - Highlights: → We investigate pulsed cathodoluminescence spectra of nanoscale alumina. → We found the intensive luminescence in the visible, NIR, and UV regions. → The transformation of R-line structure depends on phase composition of alumina. → We substantiate the relation of luminescence bands with concrete centers.

  2. Phase difference statistics related to sensor and forest parameters

    Science.gov (United States)

    Lopes, A.; Mougin, E.; Beaudoin, A.; Goze, S.; Nezry, E.; Touzi, R.; Karam, M. A.; Fung, A. K.

    1992-01-01

    The information content of ordinary synthetic aperture radar (SAR) data is principally contained in the radiometric polarization channels, i.e., the four Ihh, Ivv, Ihv and Ivh backscattered intensities. In the case of clutter, polarimetric information is given by the four complex degrees of coherence, from which the mean polarization phase differences (PPD), correlation coefficients or degrees of polarization can be deduced. For radiometric features, the polarimetric parameters are corrupted by multiplicative speckle noise and by some sensor effects. The PPD distribution is related to the sensor, speckle and terrain properties. Experimental results are given for the variation of the terrain hh/vv mean phase difference and magnitude of the degree of coherence observed on bare soil and on different pine forest stands.

  3. VLF modal interference distance and nighttime D region VLF reflection height for west-east and east-west propagation paths to Fiji

    Science.gov (United States)

    Chand, Atishnal Elvin; Kumar, Sushil

    2017-08-01

    Very low frequency (VLF) signals from navigational transmitters propagate through the Earth-ionosphere waveguide formed by the Earth and the lower conducting ionosphere and show the pronounced minima during solar terminator transition between transmitter and receiver. Pronounced amplitude minima observed on 19.8 kHz (NWC transmitter) and 24.8 kHz (NLK transmitter) signals recorded at Suva (18.149°S, 178.446°E), Fiji, during 2013-2014, have been used to estimate the VLF modal interference distance (DMS) and nighttime D region VLF reflection height (hN). The NWC transmitter signal propagates mostly in west-east direction, and the NLK transmitter follows a transequatorial path propagating significantly in the east-west direction. The values of DMS calculated using midpath terminator speed are 2103 ± 172 km and 2507 ± 373 km for these paths having west-east and east-west components of VLF subionospheric propagation, respectively, which agree with previously published results and within 10% with theoretical values. We have also compared the DMS estimated using a terminator time method with that calculated using terminator speed for a particular day and found both the values to be consistent. The hN values were found to be maximum during winter of Southern Hemisphere for NWC signal and winter of Northern Hemisphere for NLK signal VLF propagation paths to Suva. The hN also shows significant day-to-day and seasonal variabilities with a maximum of about 10 km and 23 km for NWC and NLK signal propagation paths, respectively, which could be due to the atmospheric gravity waves associated with solar terminator transition, as well as meteorological factors such as strong lightnings.

  4. ELF-VLF communications through-the-Earth

    Science.gov (United States)

    Buettner, H. M.; Burke, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

    1985-06-01

    We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified Earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constants of the rock, the noise characteristics, and modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

  5. Investigation of Polarization Phase Difference Related to Forest Fields Characterizations

    Science.gov (United States)

    Majidi, M.; Maghsoudi, Y.

    2013-09-01

    The information content of Synthetic Aperture Radar (SAR) data significantly included in the radiometric polarization channels, hence polarimetric SAR data should be analyzed in relation with target structure. The importance of the phase difference between two co-polarized scattered signals due to the possible association between the biophysical parameters and the measured Polarization Phase Difference (PPD) statistics of the backscattered signal recorded components has been recognized in geophysical remote sensing. This paper examines two Radarsat-2 images statistics of the phase difference to describe the feasibility of relationship with the physical properties of scattering targets and tries to understand relevance of PPD statistics with various types of forest fields. As well as variation of incidence angle due to affecting on PPD statistics is investigated. The experimental forest pieces that are used in this research are characterized white pine (Pinus strobus L.), red pine (Pinus resinosa Ait.), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench Voss), black spruce (Picea mariana (Mill) B.S.P.), poplar (Populus L.), red oak (Quercus rubra L.) , aspen and ground vegetation. The experimental results show that despite of biophysical parameters have a wide diversity, PPD statistics are almost the same. Forest fields distributions as distributed targets have close to zero means regardless of the incidence angle. Also, The PPD distribution are function of both target and sensor parameters, but for more appropriate examination related to PPD statistics the observations should made in the leaf-off season or in bands with lower frequencies.

  6. INVESTIGATION OF POLARIZATION PHASE DIFFERENCE RELATED TO FOREST FIELDS CHARACTERIZATIONS

    Directory of Open Access Journals (Sweden)

    M. Majidi

    2013-09-01

    Full Text Available The information content of Synthetic Aperture Radar (SAR data significantly included in the radiometric polarization channels, hence polarimetric SAR data should be analyzed in relation with target structure. The importance of the phase difference between two co-polarized scattered signals due to the possible association between the biophysical parameters and the measured Polarization Phase Difference (PPD statistics of the backscattered signal recorded components has been recognized in geophysical remote sensing. This paper examines two Radarsat-2 images statistics of the phase difference to describe the feasibility of relationship with the physical properties of scattering targets and tries to understand relevance of PPD statistics with various types of forest fields. As well as variation of incidence angle due to affecting on PPD statistics is investigated. The experimental forest pieces that are used in this research are characterized white pine (Pinus strobus L., red pine (Pinus resinosa Ait., jack pine (Pinus banksiana Lamb., white spruce (Picea glauca (Moench Voss, black spruce (Picea mariana (Mill B.S.P., poplar (Populus L., red oak (Quercus rubra L. , aspen and ground vegetation. The experimental results show that despite of biophysical parameters have a wide diversity, PPD statistics are almost the same. Forest fields distributions as distributed targets have close to zero means regardless of the incidence angle. Also, The PPD distribution are function of both target and sensor parameters, but for more appropriate examination related to PPD statistics the observations should made in the leaf-off season or in bands with lower frequencies.

  7. Perturbations of ionosphere-magnetosphere coupling by powerful VLF emissions from ground-based transmitters

    International Nuclear Information System (INIS)

    Belov, A. S.; Markov, G. A.; Ryabov, A. O.; Parrot, M.

    2012-01-01

    The characteristics of the plasma-wave disturbances stimulated in the near-Earth plasma by powerful VLF radiation from ground-based transmitters are investigated. Radio communication VLF transmitters of about 1 MW in power are shown to produce artificial plasma-wave channels (density ducts) in the near-Earth space that originate in the lower ionosphere above the disturbing emission source and extend through the entire ionosphere and magnetosphere of the Earth along the magnetic field lines. Measurements with the onboard equipment of the DEMETER satellite have revealed that under the action of emission from the NWC transmitter, which is one of the most powerful VLF radio transmitters, the generation of quasi-electrostatic (plasma) waves is observed on most of the satellite trajectory along the disturbed magnetic flux tube. This may probably be indicative of stimulated emission of a magnetospheric maser.

  8. Voices from different cultures: Foundation Phase students’ understanding across

    Directory of Open Access Journals (Sweden)

    Annalie Botha

    2011-12-01

    can extend boundaries beyond our single perspectives and experiences to the varying perspectives of others. This becomes particularly important for teachers of young children who may have very different life experiences from those of the children they teach. In this project, we examined storytelling as a way to cross-cultural boundaries and of harnessing the diverse worlds of South African citizens pedagogically. We asked fourth year students in a Foundation Phase teacher education programme to identify a person from a different cultural and linguistic group; and to have that person share a story with them to discover how the experience of listening to stories from different cultures, languages, and belief systems might influence their attitudes towards teaching children with those characteristic differences.

  9. Similar Data Retrieval from Enormous Datasets on ELF/VLF Wave Spectrum Observed by Akebono

    Directory of Open Access Journals (Sweden)

    Y Kasahara

    2010-02-01

    Full Text Available As the total amount of data measured by scientific spacecraft is drastically increasing, it is necessary for researchers to develop new computation methods for efficient analysis of these enormous datasets. In the present study, we propose a new algorithm for similar data retrieval. We first discuss key descriptors that represent characteristics of the VLF/ELF waves observed by the Akebono spacecraft. Second, an algorithm for similar data retrieval is introduced. Finally, we demonstrate that the developed algorithm works well for the retrieval of the VLF spectrum with a small amount of CPU load.

  10. Two-phase exchangers with small temperature differences

    International Nuclear Information System (INIS)

    Moracchioli, R.; Marie, G.; Lallee, J. de.

    1976-01-01

    The possibility in using heat available at low temperature level is shown (industrial wastes, solar energy, geothermal energy, heat power from seas). Special emphasis is put on the importance of heat exchangers that commonly should be evaporators and condensors working with small temperature differences (20 to 100 deg C). The expansion of the so-called ''new'' energies or recovery processes will depend on the physical performance of exchangers (Rankine two-phase cycles) and cost of the elementary exchange interfaces and assembling technics [fr

  11. Electron precipitation induced by VLF noise bursts at the plasmapause and detected at conjugate ground stations

    International Nuclear Information System (INIS)

    Dingle, B.; Carpenter, D.L.

    1981-01-01

    A new type of wave-induced electron precipitation event has been identified. During observations at conjugate stations Siple, Antarctica, and Roberval, Canada (L-4.2), VLF noise bursts were found to be associated on a one-to-one basis with amplitude perturbations of subionispheric radio propagation. The amplitude perturbations are attributed to patches of enhanced ionization that extended below approx.80 km in the nighttime ionosphere and that were produced by precipitating electron bursts. Similar amplitude perturbations seen previously were correlated with whistlers that propagated within the plasmasphere. For the new events the driving waves were structured collections of rising elements that propagated just beyond the plasmapause at roughly 5-min intervals over a several-hour period. These noise bursts were of relatively long duration (approx.10 s) and strong intensity (inferred to be >30 pT at the equator). Triggering of the noise bursts appears to have been mostly by whistlers but changed in character with time. Some later bursts had narrowband precursors at constant frequencies possibly locked to power line harmonic radiation. The burst initiation characteristics suggest the existence of a variable threshold for rapid temporal growth in the magnetosphere controlled by the trapped electron dynamics. The temporal signatures of the amplitude perturbations show that precipitation was maintained over multiple bounces of the trapped magnetospheric electrons. In some cases these signatures include a new undershoot effect during the recovery phase lasting 2--5 min. This effect may have been related to cutoff of background drizzle precipitation. Precipitation effects were observed on both long (approx.10 Mm) and short (approx.1/2 Mm) subionospheric paths and were monitored simultaneously at the conjugate stations. Similarities in the perturbation signatures on long and short paths suggest that the form of the signatures was governed by ionospheric changes

  12. Subionospheric VLF signatures and their association with sprites observed during EuroSprite 2003

    DEFF Research Database (Denmark)

    Mika, A.; Haldoupis, C.; Marshall, R.A.

    2005-01-01

    In this study, VLF observations during EuroSprite-2003 are analyzed in connection with many sprites observed above thunderstorms in central France. The sprites were detected with a sensitive camera from the Observatoire du Pic du Midi in the Pyrenees overlooking storms monitored by the French nat...

  13. The VLF Wave and Particle Precipitation Mapper (VPM) Cubesat Payload Suite

    Science.gov (United States)

    Inan, U.; Linscott, I.; Marshall, R. A.; Lauben, D.; Starks, M. J.; Doolittle, J. H.

    2012-12-01

    The VLF Wave and Particle Precipitation Mapper (VPM) payload is under development at Stanford University for a Cubesat mission that is planned to fly in low-earth-orbit in 2015. The VPM payload suite includes a 2-meter electric-field dipole antenna; a single-axis magnetic search coil; and a two-channel relativistic electron detector, measuring both trapped and loss-cone electrons. VPM will measure waves and relativistic electrons with the following primary goals: i) develop an improved climatology of plasmaspheric hiss in the L-shell range 1 < L < 3 at all local times; ii) detect VLF waves launched by space-based VLF transmitters, as well as energetic electrons scattered by those in-situ injected waves; iii) develop an improved climatology of lightning-generated whistlers and lightning-induced electron precipitation; iv)measure waves and electron precipitation produced by ground-based VLF transmitters; and v) validate propagation and wave-particle interaction models. In this paper we outline these science objectives of the VPM payload instrument suite, and describe the payload instruments and data products that will meet these science goals.

  14. Quasi-periodic VLF emissions observed during daytime at a low ...

    Indian Academy of Sciences (India)

    at a low latitude Indian ground station Jammu. K K Singh1, J .... Figure 4. Typical example of pulsing VLF hiss emission of longer period recorded during daytime at Jammu on 20 ..... Further,. Ward (1983) also paid attention to a certain simi-.

  15. Training School Pupils in the Scientific Method: Student Participation in an International VLF Radio Experiment

    Science.gov (United States)

    Denton, J. J.; Denton, M. H.; Kavanagh, A. J.; Harron, H.; Ulich, T.; Denton, J. S.

    2012-01-01

    We report on a school-university collaboration to involve students in the deployment, testing, and operation of a very low frequency (VLF) radio receiver as part of an international network of such experiments. A background to the collaboration is presented, along with a summary of planning and development, and the ultimate deployment of the…

  16. Spatial distribution and temporal variations of occurrence frequency of lightning whistlers observed by VLF/WBA onboard Akebono

    Science.gov (United States)

    Oike, Yuta; Kasahara, Yoshiya; Goto, Yoshitaka

    2014-09-01

    We statistically analyzed lightning whistlers detected from the analog waveform data below 15 kHz observed by the VLF instruments onboard Akebono. We examined the large amount of data obtained at Uchinoura Space Center in Japan for 22 years from 1989 to 2010. The lightning whistlers were mainly observed inside the L shell region below 2. Seasonal dependence of the occurrence frequency of lightning whistlers has two peaks around July to August and December to January. As lightning is most active in summer, in general, these two peaks correspond to summer in the Northern and Southern Hemispheres, respectively. Diurnal variation of the occurrence frequency showed that lightning whistlers begin to increase in the early evening and remain at a high-occurrence level through the night with a peak around 21 in magnetic local time (MLT). This peak shifts toward nightside compared with lightning activity, which begins to rise around noon and peaks in the late afternoon. This trend is supposed to be caused by attenuation of VLF wave in the ionosphere in the daytime. Comparison study with the ground-based observation revealed consistent results, except that the peak of the ground-based observation appeared after midnight while our measurements obtained by Akebono was around 21 in MLT. This difference is explained qualitatively in terms that lightning whistlers measured at the ground station passed through the ionosphere twice above both source region and the ground station. These facts provide an important clue to evaluate quantitatively the absorption effect of lightning whistler in the ionosphere.

  17. Response of the mid-latitude D-region ionosphere to the total solar eclipse of 22 July 2009 studied using VLF signals in South Korean peninsula

    Science.gov (United States)

    Phanikumar, D. V.; Kwak, Y.-S.; Patra, A. K.; Maurya, A. K.; Singh, Rajesh; Park, S.-M.

    2014-09-01

    In this paper, we analyze VLF signals received at Busan to study the the D-region changes linked with the solar eclipse event of 22 July 2009 for very short (∼390 km) transmitter-receiver great circle path (TRGCP) during local noon time 00:36-03:13 UT (09:36-12:13 KST). The eclipse crossed south of Busan with a maximum obscuration of ∼84%. Observations clearly show a reduction of ∼6.2 dB in the VLF signal strength at the time of maximum solar obscuration (84% at 01:53 UT) as compared to those observed on the control days. Estimated values of change in Wait ionospheric parameters: reflection height (h‧) in km and inverse scale height parameter (β) in km-1 from Long Wave Propagation Capability (LWPC) model during the maximum eclipse phase as compared to unperturbed ionosphere are 7 km and 0.055 km-1, respectively. Moreover, the D-region electron density estimated from model computation shows 95% depletion in electron density at the height of ∼71 km. The reflection height is found to increase by ∼7 km in the D-region during the eclipse as compared to those on the control days, implying a depletion in the Lyman-α flux by a factor of ∼7. The present observations are discussed in the light of current understanding on the solar eclipse induced D-region dynamics.

  18. Lightning characteristics observed by a VLF/LF lightning detection network (LINET in Brazil, Australia, Africa and Germany

    Directory of Open Access Journals (Sweden)

    H. Höller

    2009-10-01

    Full Text Available This paper describes lightning characteristics as obtained in four sets of lightning measurements during recent field campaigns in different parts of the world from mid-latitudes to the tropics by the novel VLF/LF (very low frequency/low frequency lightning detection network (LINET. The paper gives a general overview on the approach, and a synopsis of the statistical results for the observation periods as a whole and for one special day in each region. The focus is on the characteristics of lightning which can specifically be observed by this system like intra-cloud and cloud-to-ground stroke statistics, vertical distributions of intra-cloud strokes or peak current distributions. Some conclusions regarding lightning produced NOx are also presented as this was one of the aims of the tropical field campaigns TROCCINOX (Tropical Convection, Cirrus and Nitrogen Oxides Experiment and TroCCiBras (Tropical Convection and Cirrus Experiment Brazil in Brazil during January/February 2005, SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere and TWP-ICE (Tropical Warm Pool-International Cloud Experiment during November/December 2005 and January/February 2006, respectively, in the Darwin area in N-Australia, and of AMMA (African Monsoon Multidisciplinary Analyses in W-Africa during June–November 2006.

    Regional and temporal characteristics of lightning are found to be dependent on orographic effects (e.g. S-Germany, Brazil, Benin, land-sea breeze circulations (N-Australia and especially the evolution of the monsoons (Benin, N-Australia. Large intra-seasonal variability in lightning occurrence was found for the Australian monsoon between the strong convection during build-up and break phases and the weak active monsoon phase with only minor lightning activity. Total daily lightning stroke rates can be of comparable intensity in all regions with the heaviest events found in Germany and N

  19. On analytical justification of phase synchronization in different chaotic systems

    International Nuclear Information System (INIS)

    Erjaee, G.H.

    2009-01-01

    In analytical or numerical synchronizations studies of coupled chaotic systems the phase synchronizations have less considered in the leading literatures. This article is an attempt to find a sufficient analytical condition for stability of phase synchronization in some coupled chaotic systems. The method of nonlinear feedback function and the scheme of matrix measure have been used to justify this analytical stability, and tested numerically for the existence of the phase synchronization in some coupled chaotic systems.

  20. Geometric phase of neutrinos: Differences between Dirac and Majorana neutrinos

    Science.gov (United States)

    Capolupo, A.; Giampaolo, S. M.; Hiesmayr, B. C.; Vitiello, G.

    2018-05-01

    We analyze the non-cyclic geometric phase for neutrinos. We find that the geometric phase and the total phase associated to the mixing phenomenon provide a theoretical tool to distinguish between Dirac and Majorana neutrinos. Our results hold for neutrinos propagating in vacuum and through the matter. We feed the values of the experimental parameters in our formulas in order to make contact with experiments. Although it remains an open question how the geometric phase of neutrinos could be detected, our theoretical results may open new scenarios in the investigation of the neutrino nature.

  1. Study of apparent diffusion coefficient value in breasts of different ages and different menstrual phases

    International Nuclear Information System (INIS)

    Zhu Ping; Wang Yafei; Huang Hao; Liu Qinfang; Chen Yerong; Tan Jishan

    2011-01-01

    Objective: To analyze the differences of ADC values in breasts of women of different ages and different menstrual phases, so as to direct the choice of the examination time of MR DWI. Methods: The breasts of 65 healthy volunteers were scanned with the routine MRI plain scan and DWI in the menstrual, proliferative and secretary phases. DWI was conducted with single shot echo planar imaging technique and b value were 0, 1000 s/mm 2 . The women were divided into three groups: Group 1 (aged 20 to 29 years, 21 cases), Group 2 (aged 30 to 39, 21 cases), and Group 3 (aged 40 to 49, 23 cases). The ADC values of all 130 breasts at nipple level in the different phases were measured. The ADC values in the three age groups and in the different menstrual phases were compared using ANOVA. Results: The mean ADC values of Group 1 were (2.14±0.14) × 10 -3 , (2.03±0.18) × 10 -3 and (2.10±0.19) × 10 -3 mm 2 /s for left breast, and (2.08±0.17) × 10 -3 . (2.02±0.16) × 10 -3 and (2.09±0.17) × 10 -3 mm 2 /s for right breast in the menstrual, proliferative and secretary phases. They were slightly higher than Group 3, which were (2.02±0.27) × 10 -3 (1.97±0.25) × 10 -3 and (2.03±0.22) × 10 -3 mm 2 /s for left breast and (1.99±0.29) × 10 -3 , (1.93±0.26) × 10 -3 and (2.03±0.28) × 10 -3 mm 2 /s for right breast. The mean ADC values of Group 2 [left breast: ( 1.94 + 0. 25) × 10-3, (1.91±0.21) × 10 -3 and (1.97±0.21) × 10 -3 mm 2 /s; right breast: (1.97±0.26) × 10 -3 , (1.89± 0.25) × 10 -3 and (1.96±0.22) × 10 -3 mm 2 /s] were the lowest among the three age groups. There were significant differences in different menstrual phases (F=23.600, P 0.05). Conclusions: The mean ADC values of breasts decrease markedly in the proliferative phase. The effects of the menstrual cycle on the breast ADC values should be considered in the evaluation of breast diseases with DWI. (authors)

  2. Evaluation of Dietary Glycerin Inclusion During Different Broiler Rearing Phases

    Directory of Open Access Journals (Sweden)

    LW Freitas

    Full Text Available ABSTRACT The objective of this study was to evaluate the effect of the dietary addition of different levels of glycerin on the performance, litter moisture, pododermatitis incidence, and carcass and parts yield of broilers. In total, 1,610 broilers were reared in 35 pens with 46 birds each. A completely randomized experimental design, with five treatments with seven replicates was applied. The experimental treatments were: T1: control diet; T2: dietary inclusion of 5% glycerin from 1-42 days of age; T3: dietary inclusion of 10% glycerin from 1-42 days of age; T4: dietary inclusion of 5% glycerin from 7-42 days of age; T5: dietary inclusion of 10% glycerin from 7-42 days of age. The diets containing glycerin fed since the pre-starter period improved broiler weight gain and feed conversion ratio, but did not influence feed intake or livability. At the end of the experiment, the production efficiency index of the broilers fed 10% glycerin during the entire rearing period was significantly reduced compared with the other treatments. Litter moisture in the pens of broilers fed 10% glycerin during the entire rearing period was higher compared to the other treatments since day 21.Diets containing 10% glycerin, both for the entire rearing period (1-42 days or only after the pre-starter phase (7-42 days, influenced broiler performance and incidence of severe pododermatitis, reducing the production efficiency indexes at 42 days. Glycerin may be added up to 5% in broiler´s diets with no effect on performance, litter moisture and carcass yield, indicating that this co-product of the biodiesel industry can be used as an alternative feedstuff for broilers.

  3. Excitation of VLF quasi-electrostatic oscillations in the ionospheric plasma

    Directory of Open Access Journals (Sweden)

    B. Lundin

    Full Text Available A numerical solution of the dispersion equation for electromagnetic waves in a hot magnetized collisionless plasma has shown that, in a current-free ionospheric plasma, the distortion of the electron distribution function reproducing the downward flow of a thermal electron component and the compensating upward flow of the suprathermal electrons, which are responsible for the resulting heat flux, can destabilize quasi-electrostatic ion sound waves. The numerical analysis, performed with ion densities and electron temperature taken from the data recorded by the Interkosmos-24 (IK-24, Aktivny satellite, is compared with a VLF spectrum registered at the same time on board. This spectrum shows a wide frequency band emission below the local ion plasma frequency. The direction of the electron heat flux inherent to the assumed model of VLF emission generation is discussed

  4. Rocket investigations of electron precipitation and VLF waves in the Antarctic upper atmosphere

    International Nuclear Information System (INIS)

    Sheldon, W.R.; Benbrook, J.R.; Bering, E.A.

    1988-01-01

    The results of two Antarctic rocket campaigns, primarily initiated to investigate electron precipitation stimulated by signals from the Siple-Station ground-based VLF transmitter, are presented. While the primary objective of the campaigns was not achieved, the Siple VLF transmitter facilitated a study of the wave environment in the ionosphere. Standing wave patterns in the ionosphere were observed for the first time by detectors flown aboard the Nike-Tomahawk rockets; the same detectors monitored a continuous signal from the transmitter through the neutral atmosphere and into the ionosphere, providing unique data for comparison with theoretical studies of wave propagation. The measurements of penetrating electron precipitation were interpreted in terms of a model of energetic electron precipitation from the trapped radiational belts. 52 references

  5. Excitation of VLF quasi-electrostatic oscillations in the ionospheric plasma

    Directory of Open Access Journals (Sweden)

    B. Lundin

    1996-01-01

    Full Text Available A numerical solution of the dispersion equation for electromagnetic waves in a hot magnetized collisionless plasma has shown that, in a current-free ionospheric plasma, the distortion of the electron distribution function reproducing the downward flow of a thermal electron component and the compensating upward flow of the suprathermal electrons, which are responsible for the resulting heat flux, can destabilize quasi-electrostatic ion sound waves. The numerical analysis, performed with ion densities and electron temperature taken from the data recorded by the Interkosmos-24 (IK-24, Aktivny satellite, is compared with a VLF spectrum registered at the same time on board. This spectrum shows a wide frequency band emission below the local ion plasma frequency. The direction of the electron heat flux inherent to the assumed model of VLF emission generation is discussed

  6. VLF and X-ray Instruments for Stratospheric Balloons: ABOVE2 and EPEx

    Science.gov (United States)

    Cully, C. M.; Galts, D.; Patrick, M.; Duffin, C.; Jang, A. C.; Pitzel, J.; Trumpour, T.; McCarthy, M.; Milling, D. K.

    2017-12-01

    The ABOVE2 (2016) and EPEx (2018) stratospheric balloon missions are designed to study energetic electrons precipitating from the radiation belts into the atmosphere. The payloads include instruments that measure Very Low Frequency (VLF) magnetic and electric fields, and bremsstrahlung X-rays. The ABOVE2 VLF instrument is an FPGA-based design with >200 kHz sampling rates, sub-microsecond timing accuracy and onboard spectral processing, designed in a Cubesat-friendly format. The EPEx X-ray instrument is a hard X-ray imaging system, also in a Cubesat-friendly format, incorporating a commercially-available Cadmium-Zinc-Telluride module. The imager is sufficiently lightweight that we can launch it on-demand with low-volume latex balloons. I will discuss the design and performance of both instruments, and present data from the ABOVE2 flights.

  7. Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low Altitude VLF Transmitter

    Science.gov (United States)

    2009-03-31

    AFRL-RV-HA-TR-2009-1055 Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low Altitude VLF Transmitter ...m (or even 500 m) at mid to high latitudes . At low latitudes , the FDTD model exhibits variations that make it difficult to determine a reliable...Scientific, Final 3. DATES COVERED (From - To) 02-08-2006 – 31-12-2008 4. TITLE AND SUBTITLE Accurate Modeling of Ionospheric Electromagnetic Fields

  8. Relationship between median intensities of electromagnetic emissions in the VLF range and lightning activity

    Czech Academy of Sciences Publication Activity Database

    Němec, František; Santolík, Ondřej; Parrot, M.; Rodger, C. J.

    2010-01-01

    Roč. 115, - (2010), A08315/1-A08315/10 ISSN 0148-0227 R&D Projects: GA ČR GA205/09/1253; GA ČR GAP205/10/2279; GA MŠk ME09107 Institutional research plan: CEZ:AV0Z30420517 Keywords : lightning activity * VLF electromagnetic waves * DEMETER satellite Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.303, year: 2010

  9. Lifshitz-Slyozov kinetics of a nonconserved system that separates into phases of different density

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Shah, Peter Jivan; Andersen, Jørgen Vitting

    1990-01-01

    Computer-simulation techniques are applied to analyze the late-stage ordering kinetics of a two-dimensional annealed dilute Ising model quenched into regions of its phase diagram that involve phase separation of phases with different densities. The order parameter of the model is a nonconserved...... of the phase-separation kinetics in O/W(110) systems at high coverage....

  10. ELF and VLF signatures of sprites registered onboard the low altitude satellite DEMETER

    Directory of Open Access Journals (Sweden)

    J. Błęcki

    2009-06-01

    Full Text Available We report the observation of ELF and VLF signature of sprites recorded on the low altitude satellite DEMETER during thunderstorm activity. At an altitude of ~700 km, waves observed on the E-field spectrograms at mid-to-low latitudes during night time are mainly dominated by up-going 0+ whistlers. During the night of 20 July 2007 two sprites have been observed around 20:10:08 UT from the observatory located on the top of the mountain Śnieżka in Poland (50°44'09" N, 15°44'21" E, 1603 m and, ELF and VLF data have been recorded by the satellite at about 1200 km from the region of thunderstorm activity. During this event, the DEMETER instruments were switched in the burst mode and it was possible to register the wave forms. It is shown that the two sprites have been triggered by two intense +CG lightning strokes (100 kA occurring during the same millisecond but not at the same location. Despite the distance DEMETER has recorded at the same time intense and unusual ELF and VLF emissions. It is shown that the whistler wave propagates from the thunderstorm regions in the Earth-ionosphere guide and enters in the ionosphere below the satellite. They last several tens of milliseconds and the intensity of the ELF waveform is close to 1 mV/m. A particularly intense proton whistler is also associated with these emissions.

  11. Phase transitions in PZT ceramics prepared by different techniques

    Czech Academy of Sciences Publication Activity Database

    Deineka, Alexander; Suchaneck, G.; Jastrabík, Lubomír; Gerlach, G.

    2002-01-01

    Roč. 41, 11B (2002), s. 6966-6968 ISSN 0021-4922 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010914 Keywords : PZT * phase transitions * band gap * ferroelectrics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.280, year: 2002

  12. The role of habit in different phases of exercise.

    Science.gov (United States)

    Kaushal, Navin; Rhodes, Ryan E; Meldrum, John T; Spence, John C

    2017-09-01

    The primary purpose of this study was to investigate how habit strength in a preparatory and performance phase predicts exercise while accounting for intention. The secondary purpose was to determine the strength of potential habit antecedents (affective judgement, perceived behavioural control, consistency, and cues) in both exercise phases. This was a prospective study with measures collected at baseline and week 6. Participants (n = 181) were a sample of adults (18-65) recruited across nine gyms and recreation centres who completed baseline and follow-up questionnaires after 6 weeks. Intention (β = .28, p = .00) and habit preparation (β = .20, p = .03), predicted exercise, and change of exercise with coefficients of β = .25, (p = .00) and β = .18, (p = .04), respectively, across 6 weeks but not habit performance (p>.05). This study highlighted the distinction between the two phases of exercise and the importance of preparatory habit in predicting behaviour. Focusing on a consistent preparatory routine could be helpful in establishing an exercise habit. Statement of contribution What is already known on this subject? A recent meta-analysis found habit to correlate r = .43 with behaviour (Gardner, de Bruijn, & Lally, ). Verplanken and Melkevik () propose that habit in exercise should be measured in separate components. Phillips and Gardner () interpreted this as habitual instigation (thought) to exercise and execution. What does this study add? Extended pervious work and identified two distinct behavioural phases (preparation and performance) for exercise. Habit model revealed that temporal consistency was the strongest predictor in both phases of exercise. Intention and habit of preparatory behaviour predicted exercise fluctuations in gym members. © 2017 The British Psychological Society.

  13. Two-dimensional characteristic polynomials in the direct calculation of optical phase sum and difference

    International Nuclear Information System (INIS)

    Miranda, M; Dorrio, B V; Blanco, J; Diz-Bugarin, J; Ribas, F

    2011-01-01

    Two-stage phase shifting algorithms make possible to directly recover the sum or the difference of the encoded optical phase of two different fringe patterns. These algorithms can be constructed, for example, by combining known phase shifting algorithms in a non-linear way. In this work two-stage phase shifting algorithms are linked to a two-dimensional characteristic polynomial to qualitatively analyse their behaviour against the main systematic error sources in an analysis protocol like that used for phase shifting algorithms. This tool enables us to understand the propagation of properties from precursor phase shifting algorithms to new evaluation algorithms that can be built from them.

  14. Rosetta Phase II: Measuring and Interpreting Cultural Differences in Cognition

    National Research Council Canada - National Science Library

    Klein, Helen A; Lin, Mei-Hua; Peng, Kaiping; Bhal, Kanika; Radford, Mark H; Choi, Incheol; Mohd Noor, Noraini; Khalid, Halimahtun M; Chan, David

    2008-01-01

    .... We have taken advantage of developments in cognitive psychology to expand the test battery. This has allowed us to gain a richer picture of national differences in cognition and to capture cognitive differences important in naturalistic setting...

  15. Estimation of Existence Geothermal Manifestation Using Very Low Frequency (VLF) Method in the PagerkandangVulcanic, Dieng, Central Java

    Science.gov (United States)

    Wulandari, Asri; Asti Anggari, Ega; Dwiasih, Novi; Suyanto, Imam

    2018-03-01

    Very Low Frequency (VLF) measurement has been done at Pagerkandang Volcanic, Dieng Volcanic Complex (DVC) to examine the possible existence of conductive zones that related with geothermal manifestation. VLF – EM survey used tilt mode with T-VLF BRGM Iris Instrument operated with two frequencies, they are 22200 Hz from Japan (JJI) and 19800 Hz from Australia (NWC). There are five lines with distance between lines is 50 m, and distance between measure points is 20 m. The parameters measured from VLF method are tilt angle (%) and elliptisity (%). Data processed by tilt angle value with fraser and Karous – Hjelt filter used WinVLF program. Karous – Hjelt filter resulted current density contour to estimate lateral location from conductive and resistive zones. The conductive zone is interpreted as the area which have high current density value. This area located at eastern dan western of Pagerkandang Volcanic. The conductive zone related to geothermal manifestation as like as fumarol that appeared because presenced of normal fault. Whereas the resistive zone is interpreted as the area which have low current density value. This area spread almost in the middle of the Pagerkandang Volcanic. The resistive zone was caused by the high weathering in claystone.

  16. Note: Dynamic analysis of a robotic fish motion with a caudal fin with vertical phase differences

    Science.gov (United States)

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghwi

    2013-03-01

    In this paper, a robotic fish with a caudal fin with vertical phase differences is studied, especially focusing on the energy consumption. Energies for thrusting a conventional robotic fish and one with caudal fin with vertical phase differences are obtained and compared each other. It is shown that a robotic fish with a caudal fin with vertical phase differences can save more energy, which implies the efficient thrusting via a vertically waving caudal fin.

  17. Sebum/Meibum Surface Film Interactions and Phase Transitional Differences.

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Gerlach, Dylan; Yappert, Marta C

    2016-05-01

    Sebum may contribute to the composition of the tear film lipid layer naturally or as a contaminant artifact from collection. The aims of this study were to determine: if sebum changes the rheology of meibum surface films; if the resonance near 5.2 ppm in the 1H-NMR spectra of sebum is due to squalene (SQ); and if sebum or SQ, a major component of sebum, interacts with human meibum. Human meibum was collected from the lid margin with a platinum spatula. Human sebum was collected using lipid absorbent tape. Langmuir trough technology was used to measure the rheology of surface films. Infrared spectroscopy was used to measure lipid conformation and phase transitions. We used 1H-NMR to measure composition and confirm the primary structure of SQ. The NMR resonance near 5.2 ppm in the spectra of human sebum was from SQ which composed 28 mole percent of sebum. Both sebum and SQ lowered the lipid order of meibum. Sebum expanded meibum films at lower concentrations and condensed meibum films at higher concentrations. Sebum caused meibum to be more stable at higher pressures (greater maximum surface pressure). Physiological levels of sebum would be expected to expand or fluidize meibum making it spread better and be more surface active (qualities beneficial for tear film stability). Sebum would also be expected to stabilize the tear film lipid layer, which may allow it to withstand the high shear pressure of a blink.

  18. Sebum/Meibum Surface Film Interactions and Phase Transitional Differences

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Gerlach, Dylan; Yappert, Marta C.

    2016-01-01

    Purpose Sebum may contribute to the composition of the tear film lipid layer naturally or as a contaminant artifact from collection. The aims of this study were to determine: if sebum changes the rheology of meibum surface films; if the resonance near 5.2 ppm in the 1H-NMR spectra of sebum is due to squalene (SQ); and if sebum or SQ, a major component of sebum, interacts with human meibum. Methods Human meibum was collected from the lid margin with a platinum spatula. Human sebum was collected using lipid absorbent tape. Langmuir trough technology was used to measure the rheology of surface films. Infrared spectroscopy was used to measure lipid conformation and phase transitions. We used 1H-NMR to measure composition and confirm the primary structure of SQ. Results The NMR resonance near 5.2 ppm in the spectra of human sebum was from SQ which composed 28 mole percent of sebum. Both sebum and SQ lowered the lipid order of meibum. Sebum expanded meibum films at lower concentrations and condensed meibum films at higher concentrations. Sebum caused meibum to be more stable at higher pressures (greater maximum surface pressure). Conclusions Physiological levels of sebum would be expected to expand or fluidize meibum making it spread better and be more surface active (qualities beneficial for tear film stability). Sebum would also be expected to stabilize the tear film lipid layer, which may allow it to withstand the high shear pressure of a blink. PMID:27145473

  19. Comparison of different configurations of Phase Doppler Analyser

    Directory of Open Access Journals (Sweden)

    Zaremba Matouš

    2016-01-01

    Full Text Available A phase Doppler anemometry (PDA technique is widely used in experimental fluid mechanics to measure size and velocity of particles in the fluid flow. Even though this method is common in experimental fluid mechanics, there are only few techniques that might serve for the purpose of the evaluation of the PDA system. To examine results of the PDA visualizations techniques are usually used. However, this approach suffers from several aspects. Mainly, it is difficult to determine the exact position of the measurement volume of PDA system. Then it is complicated to determine which particles are passing through the measuring volume. Another way how to examine performance of the PDA system is to use two PDA systems simultaneously. By using one laser for both systems we can avoid previously mentioned aspects. In our experiments, we use fiber based PDA system and classical PDA system both made by Dantec Dynamics. The aim of this paper is to compare results from various configurations and highlight crucial parameters that influence measurements.

  20. Comparison of different configurations of Phase Doppler Analyser

    Science.gov (United States)

    Zaremba, Matouš; Malý, Milan; Jedelský, Jan; Jícha, Miroslav

    2016-03-01

    A phase Doppler anemometry (PDA) technique is widely used in experimental fluid mechanics to measure size and velocity of particles in the fluid flow. Even though this method is common in experimental fluid mechanics, there are only few techniques that might serve for the purpose of the evaluation of the PDA system. To examine results of the PDA visualizations techniques are usually used. However, this approach suffers from several aspects. Mainly, it is difficult to determine the exact position of the measurement volume of PDA system. Then it is complicated to determine which particles are passing through the measuring volume. Another way how to examine performance of the PDA system is to use two PDA systems simultaneously. By using one laser for both systems we can avoid previously mentioned aspects. In our experiments, we use fiber based PDA system and classical PDA system both made by Dantec Dynamics. The aim of this paper is to compare results from various configurations and highlight crucial parameters that influence measurements.

  1. RETRIEVAL OF AEROSOL PHASE FUNCTION AND POLARIZED PHASE FUNCTION FROM POLARIZATION OF SKYLIGHT FOR DIFFERENT OBSERVATION GEOMETRIES

    Directory of Open Access Journals (Sweden)

    L. Li

    2018-04-01

    Full Text Available The phase function and polarized phase function are important optical parameters, which describe scattering properties of atmospheric aerosol particles. Polarization of skylight induced by the scattering processes is sensitive to the scattering properties of aerosols. The Stokes parameters I, Q, U and the polarized radiance Lp of skylight measured by the CIMEL dual-polar sun-sky radiometer CE318- DP can be use to retrieve the phase function and polarized phase function, respectively. Two different observation geometries (i.e., the principal plane and almucantar are preformed by the CE318-DP to detect skylight polarization. Polarization of skylight depends on the illumination and observation geometries. For the same solar zenith angle, retrievals of the phase function and the polarized phase function are still affected by the observation geometry. The performance of the retrieval algorithm for the principal plane and almucantar observation geometries was assessed by the numerical experiments at two typical high and low sun’s positions (i.e. solar zenith angles are equal to 45° and 65°. Comparing the results for the principal plane and almucantar geometries, it is recommended to utilize the principal plane observations to retrieve the phase function when the solar zenith angle is small. The Stokes parameter U and the polarized radiance Lp from the almucantar observations are suggested to retrieve the polarized phase function, especially for short wavelength channels (e.g., 440 and 500 nm.

  2. Retrieval of Aerosol Phase Function and Polarized Phase Function from Polarization of Skylight for Different Observation Geometries

    Science.gov (United States)

    Li, L.; Qie, L. L.; Xu, H.; Li, Z. Q.

    2018-04-01

    The phase function and polarized phase function are important optical parameters, which describe scattering properties of atmospheric aerosol particles. Polarization of skylight induced by the scattering processes is sensitive to the scattering properties of aerosols. The Stokes parameters I, Q, U and the polarized radiance Lp of skylight measured by the CIMEL dual-polar sun-sky radiometer CE318- DP can be use to retrieve the phase function and polarized phase function, respectively. Two different observation geometries (i.e., the principal plane and almucantar) are preformed by the CE318-DP to detect skylight polarization. Polarization of skylight depends on the illumination and observation geometries. For the same solar zenith angle, retrievals of the phase function and the polarized phase function are still affected by the observation geometry. The performance of the retrieval algorithm for the principal plane and almucantar observation geometries was assessed by the numerical experiments at two typical high and low sun's positions (i.e. solar zenith angles are equal to 45° and 65°). Comparing the results for the principal plane and almucantar geometries, it is recommended to utilize the principal plane observations to retrieve the phase function when the solar zenith angle is small. The Stokes parameter U and the polarized radiance Lp from the almucantar observations are suggested to retrieve the polarized phase function, especially for short wavelength channels (e.g., 440 and 500 nm).

  3. Phase difference estimation method based on data extension and Hilbert transform

    International Nuclear Information System (INIS)

    Shen, Yan-lin; Tu, Ya-qing; Chen, Lin-jun; Shen, Ting-ao

    2015-01-01

    To improve the precision and anti-interference performance of phase difference estimation for non-integer periods of sampling signals, a phase difference estimation method based on data extension and Hilbert transform is proposed. Estimated phase difference is obtained by means of data extension, Hilbert transform, cross-correlation, auto-correlation, and weighted phase average. Theoretical analysis shows that the proposed method suppresses the end effects of Hilbert transform effectively. The results of simulations and field experiments demonstrate that the proposed method improves the anti-interference performance of phase difference estimation and has better performance of phase difference estimation than the correlation, Hilbert transform, and data extension-based correlation methods, which contribute to improving the measurement precision of the Coriolis mass flowmeter. (paper)

  4. Current-induced massless mode of the interband phase difference in two-band superconductors

    International Nuclear Information System (INIS)

    Tanaka, Y.; Hase, I.; Yanagisawa, T.; Kato, G.; Nishio, T.; Arisawa, S.

    2015-01-01

    Highlights: • A current induces an interband phase difference in two-band superconductors. • By controlling the boundary conditions, we can trap this phase difference. • A phase difference soliton is observed after switching off the current. - Abstract: There is a current-induced massless mode of an interband phase difference in two-band superconductors. For a thin wire, the externally applied current always invokes a finite interband phase difference when the end of the wire is terminated by a natural boundary condition, i.e., where the total current is specified but the other parameters are left as free and a finite interband phase difference is allowed. This condition can be realized by the normal state region formed by the shrinking of a cross section of the wire where the critical current density is lower than that of the other region of the wire. The interband interaction in the wire cannot completely prevent the emergence of the interband phase difference, though it reduces it somewhat. Instead, boundary conditions determine the presence of the interband phase difference. By reverting the normal state into the superconducting state at the shrunken region by decreasing the current, we may trap a rotation of integral multiples of 2π radians of the interband phase difference in the wire. After switching off the current, this rotation of integral multiples of 2π radians, which continuously spreads over the whole wire, is separated into several interband phase difference solitons (i-solitons), where one i-soliton locally generates a 2π interband phase difference

  5. Additional attenuation of natural VLF electromagnetic waves observed by the DEMETER spacecraft resulting from preseismic activity

    Czech Academy of Sciences Publication Activity Database

    Píša, David; Němec, F.; Santolík, Ondřej; Parrot, M.; Rycroft, M.

    2013-01-01

    Roč. 118, č. 8 (2013), s. 5286-5295 ISSN 2169-9380 R&D Projects: GA ČR(CZ) GAP209/11/2280; GA ČR GA205/09/1253 Grant - others:European Community Seventh Framework Programme (FP7/2007-2013),(XE) 262005; AV ČR(CZ) M100431206. Institutional support: RVO:68378289 Keywords : DEMETER * VLF waves * preseismic activity * Earth-ionosphere waveguide Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.440, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/jgra.50469/abstract

  6. Effect of magnetic field-aligned currents on VLF emissions in the magnetosphere

    International Nuclear Information System (INIS)

    Kulkarni, V.H.

    1988-01-01

    The dispersion relation for the electromagnetic electron cyclotron waves in the presence of magnetic field-aligned currents has been obtained. The kinetic distribution of electrons for the main body of plasma with a temperature anisotropy and a loss cone distribution have been considered. In general, it has been seen that the current moving along the direction of resonant electrons reduce the growth rate. This effect has been analysed in the case of magnetospheric plasma to suggest possible correlations between the Birkeland currents and the emissions of very low frequency (VLF) electromagnetic waves. (author). 19 refs

  7. Numerical simulation of whistler-triggered VLF emissions observed in Antartica

    Energy Technology Data Exchange (ETDEWEB)

    Nunn, D. [Southhampton Univ., Southhampton (United Kingdom); Smith, A.J. [British Antarctic Survey, Cambridge (United Kingdom)

    1996-03-01

    The authors have extracted from VLF databases from British Antarctica Survey data taken at Halley and Faraday stations, examples of whistler-triggered emissions (WTE). The WTE are relatively narrow band emissions triggered by natural background whistlers undergoing nonlinear wave particle interactions generally in the equatorial regions. They occur with either rising or falling frequency relative to the triggering waves. Using a Vlasov type code the authors are able to simulate the types of emissions which are observed. 24 refs., 8 figs., 3 tabs.

  8. Simulation of VLF chorus emissions in the magnetosphere and comparison with THEMIS spacecraft data

    Czech Academy of Sciences Publication Activity Database

    Demekhov, A. G.; Taubenschuss, Ulrich; Santolík, Ondřej

    2017-01-01

    Roč. 122, č. 1 (2017), s. 166-184 ISSN 2169-9380 R&D Projects: GA MŠk(CZ) LH15304 Grant - others:AV ČR(CZ) AP1401 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378289 Keywords : VLF chorus * THEMIS data * numerical simulations Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.733, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2016JA023057/full

  9. Right-sided phase abnormalities on gated blood pool ventriculography: Demonstration of six different patterns

    International Nuclear Information System (INIS)

    Bahar, R.H.; Abdel-Dayem, H.M.; Ziada, G.; Al-Suhali, A.; Constantinides, C.; Nair, K.M.

    1986-01-01

    Phase pattern abnormalities on multiple gated blood pool ventriculography are better reported for the left ventricle (LV) than for the right side of the heart. In a study of 92 patients who also underwent contrast ventriculography, the authors identified six different patterns of right-sided phase abnormalities and their causes: right bundle-branch block, causing delayed phase in the entire right ventricle (RV); ischemic right coronary artery disease, causing delayed phase in the inferior RV wall; pericardial effusion, causing an L-shaped area of delayed phase to the right of the septum and below the LV; pulmonary hypertension, causing delayed phase in the pulmonary infundibulum; tricuspid regurgitation, causing a crescentic area of delayed phase around and below the right RV and extending below the LV as well, and atrial septal defect causing an abnormally large auricular phase

  10. Plume Migration of Different Carbon Dioxide Phases During Geological Storage in Deep Saline Aquifers

    Directory of Open Access Journals (Sweden)

    Chien-Hao Shen

    2015-01-01

    Full Text Available This study estimates the plume migration of mobile supercritical phase (flowing, aqueous phase (dissolved, and ionic phase CO2 (bicarbonate, and evaluates the spatial distribution of immobile supercritical phase (residual and mineral phase CO2 (carbonates when CO2 was sequestered. This utilized a simulation, in an anticline structure of a deep saline aquifer in the Tiechenshan (TCS field, Taiwan. All of the trapping mechanisms and different CO2 phases were studied using the fully coupled geochemical equation-of-state GEM compositional simulator. The mobile supercritical phase CO2 moved upward and then accumulated in the up-dip of the structure because of buoyancy. A large amount of immobile supercritical phase CO2 was formed at the rear of the moving plume where the imbibition process prevailed. Both the aqueous and ionic phase CO2 finally accumulated in the down-dip of the structure because of convection. The plume volume of aqueous phase CO2 was larger than that of the supercritical phase CO2, because the convection process increased vertical sweep efficiency. The up-dip of the structure was not the major location for mineralization, which is different from mobile supercritical phase CO2 accumulation.

  11. 49 CFR 268.3 - Different phases of the Maglev Deployment Program.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Different phases of the Maglev Deployment Program... DEPLOYMENT PROGRAM Overview § 268.3 Different phases of the Maglev Deployment Program. (a) The Maglev... deadlines—based on the progress of the Maglev Deployment Program; grantees will be notified accordingly. (b...

  12. Spatial-frequency spectrum of patterns changes the visibility of spatial-phase differences

    Science.gov (United States)

    Lawton, T. B.

    1985-01-01

    It is shown that spatial-frequency components over a 4-octave range affected the visibility of spatial-phase differences. Contrast thresholds were measured for discrimination between two (+45- and -45-deg) spatial phases of a sinusoidal test grating added to a background grating. The background could contain one or several sinusoidal components, all in 0-deg phase. Phase differences between the test and the background were visible at lower contrasts when test and background frequencies were harmonically related than when they were not, when test and background frequencies were within 1 octave than when they were farther apart, when the fundamental frequency of the background was low than when it was high, and for some discriminations more than for others, after practice. The visibility of phase differences was not affected by additional components in the background if the fundamental and difference frequencies of the background remained unchanged. Observers' reports of their strategies gave information about the types of attentive processing that were used to discriminate phase differences. Attentive processing facilitated phase discrimination for multifrequency gratings spanning a much wider range of spatial frequencies than would be possible by using only local preattentive processing. These results were consistent with the visibility of phase differences being processed by some combination of even- and odd-symmetric simple cells tuned to a wide range of different spatial frequencies.

  13. Phase transformation of aluminium hydroxide to aα- alumina prepared from different aluminium salts

    International Nuclear Information System (INIS)

    Masliana Muslimin; Meor Yusoff Meor Sulaiman

    2006-01-01

    The study intends to look at the most suitable aluminium salt to produce a single-phase a-alumina by the hydrothermal method. In the process to produce alumina from the calcination of aluminium hydroxide (Al(OH) 3 ), three different aluminium salts namely aluminium sulfate (Al 2 (SO 4) 2), aluminium nitrate (A(NO 3 ) 3 ) and aluminium chloride (AlCl 3 ) were tried. The process involved the used of NH 4 OH as the precipitating medium. Aluminium hydroxide produced from each of these salts were characterised by x-ray diffraction (XRD) technique to identity the crystalline phase. Aluminium hydroxide produced by all the different aluminium salts is present as boehmite or pseudo-boehmite phase. Aluminium hydroxide produced from Al 2 (SO) 2 , Al(NO) 3 and AlCl 3 shows the transformation of the boehmite phase to a α-alumina phase at 500 0 C. On further heating, the α-alumina continuously formed at 800 o C followed soon at 1000 o C. But for the Al(NO3) 3 salts a different phase transitions occurs on heating especially at 1000 o C. Here it was observed not a single alumina phase is presence but the presence of both α and γ--alumina phases. At 1300 o C, the single α-alumina phase was formed. The study concluded that aluminium sulphate is recommended in order to obtain a single-phase α-alumina with the required characteristics. (Author)

  14. Radial plasma drifts deduced from VLF whistler mode signals - A modelling study

    Science.gov (United States)

    Poulter, E. M.; Andrews, M. K.; Bailey, G. J.; Moffett, R. J.

    1984-05-01

    VLF whistler mode signals have previously been used to infer radial plasma drifts in the equatorial plane of the plasmasphere and the field-aligned ionosphere-protonosphere coupling fluxes. Physical models of the plasmasphere consisting of O(+) adn H(+) ions along dipole magnetic field lines, and including radial E x B drifts, are applied to a mid-latitude flux tube appropriate to whistler mode signals received at Wellington, New Zealand, from the fixed frequency VLF transmitter NLK (18.6 kHz) in Seattle, U.S.A. These models are first shown to provide a good representation of the recorded Doppler shift and group delay data. They are then used to simulate the process of deducing the drifts and fluxes from the recorded data. Provided the initial whistler mode duct latitude and the ionospheric contributions are known, the drifts at the equatorial plane can be estimated to about + or - 20 m/s (approximately 10-15 percent), and the two hemisphere ionosphere-protonosphere coupling fluxes to about + or - 10 to the 12th/sq m-sec (approximately 40 percent).

  15. Variations of the VLF/LF signals during seismic activity in Japan in November 2016

    Science.gov (United States)

    Rozhnoi, Alexander; Solovieva, Maria; Levin, Boris; Chebrov, Danila; Hayakawa, Masashi; Fedun, Viktor

    2017-04-01

    The measurements of the very low and low frequency (VLF/LF) signals at the Petropavlovsk-Kamchatsky and Yuzhno-Sakhalinsk stations were used for the analysis in connection with two underwater earthquakes which occurred near Japan in November 2016. The first earthquake with M=6.1 (depth 42 km) happened on 11 November. The second earthquake was recorded on 21 November with M=6.9 (depth 11 km) and had series of aftershocks with M up to 5.6 (USGS/NEIC). The significant negative nighttime amplitude anomalies were found for two sub-ionospheric paths: NWC-Petropavlovsk-Kamchatsky and JJY-Yuzhno-Sakhalinsk during about a week in case of the first earthquake. The anomalies of signal in the path JJY-Petropavlovsk-Kamchatsky were observed during 4-5 days before the second earthquake and during 3 days after it. Taking into account the possible influence of other factors which can produce perturbations in VLF/LF signals (geomagnetic storm, proton burst and the relativistic electron fluxes, as well as atmospheric parameters), also using control paths, we may conclude that observed anomalies very likely were caused by impending earthquakes.

  16. Rocket observations of the precipitation of electrons by ground VLF transmitters

    International Nuclear Information System (INIS)

    Arnoldy, R.L.; Kintner, P.M.

    1989-01-01

    Below an altitude of 400 km or less over the NASA Wallops Island range, stably trapped particles do not exist because of the South Atlantic Anomaly. In an experiment to measure scattered electrons at these altitudes (NASA flight 36:013), electron detectors clearly measured two monoenergetic electron peaks above the low background. The two monoernergetic peaks are attributed to the resonant interaction of electrons with VLF waves from Navy ground transmitters at Cutler, Maine, and Annapolis, Maryland. The transmitter signals were measured with electric and magnetic receivers aboard the rocket, and their propagation through the ionosphere and correlation with the precipitated electrons are discussed. In addition, energetic ions were also measured to be in the bounce loss cone during this rocket flight. Because of increased geomagnetic activity, it apears that the ring current extended inward to at least the L=2.5 magnetic shell and enhanced convection eroded the plasmasphere. The inward movement or compression of the plasmapause is consistent with a steep gradient in the equatorial cold plasma density and a localized equatorial interaction region needed to account for the monoenergetic elecrtron precipitation. The role of the geomagnetic activity in ''priming'' the trapped electron population for cyclotron resonance with VLF waves such that there is continuous scattering into the bounce loss cone remains uncertain. copyright American Geophysical Union 1989

  17. Characteristics of VLF/LF Sferics from Elve-producing Lightning Discharges

    Science.gov (United States)

    Blaes, P.; Zoghzoghy, F. G.; Marshall, R. A.

    2013-12-01

    Lightning return strokes radiate an electromagnetic pulse (EMP) which interacts with the D-region ionosphere; the largest EMPs produce new ionization, heating, and optical emissions known as elves. Elves are at least six times more common than sprites and other transient luminous events. Though the probability that a lightning return stroke will produce an elve is correlated with the return stroke peak current, many large peak current strokes do not produce visible elves. Apart from the lightning peak current, elve production may depend on the return stroke speed, lightning altitude, and ionospheric conditions. In this work we investigate the detailed structure of lightning that gives rise to elves by analyzing the characteristics of VLF/LF lightning sferics in conjunction with optical elve observations. Lightning sferics were observed using an array of six VLF/LF receivers (1 MHz sample-rate) in Oklahoma, and elves were observed using two high-speed photometers pointed over the Oklahoma region: one located at Langmuir Laboratory, NM and the other at McDonald Observatory, TX. Hundreds of elves with coincident LF sferics were observed during the summer months of 2013. We present data comparing the characteristics of elve-producing and non-elve producing lightning as measured by LF sferics. In addition, we compare these sferic and elve observations with FDTD simulations to determine key properties of elve-producing lightning.

  18. Comparative study of interventricular phase difference and pressure gradient in cases of isolated ventricular septal defect

    Energy Technology Data Exchange (ETDEWEB)

    Elhaddad, SH; Moustafa, H; Ziada, G; Seleem, Z; Elsabban, KH; Mahmoud, F [Nuclear medicine department and pediatric cardiology department Faculty of medicine, Cairo university, Cairo, (Egypt)

    1995-10-01

    One hundred and fifty patients with isolated VSD were evaluated by radionuclide MUGA study and Echo-Doppler. Difference between phase angle of the right and left ventricles as detected by MUGA had been divided into main four groups according to pressure gradient between the two ventricles : group I (with pressure gradient {<=}30 mmHg and phase difference 80.10 degree{+-}34.1), group III (with pressure gradient > 70 mmHg and phase difference -0.5 degree {+-} 8.4). It has been found that there was a significant difference between the 4 groups as regards right - to - left ventricular phase difference (P<0.0001). There was significant delay in emptying of right ventricle in groups with pressure gradient < 50 mmHg. Regression analysis revealed inverse correlation between right -to- left ventricular phase difference with changes in pressure gradient (r= 0.81). Similarly, significant correlation had been found between right -to-left ventricular phase difference in relation Qp/Qs (r=0.85); conclusion: interventricular phase difference can be used to evaluate interventricular pressure gradient in cases of isolated VSD. 4 figs., 2 tabs.

  19. Statistical correlation of spectral broadening in VLF transmitter signal and low-frequency ionospheric turbulence from observation on DEMETER satellite

    Directory of Open Access Journals (Sweden)

    A. Rozhnoi

    2008-10-01

    Full Text Available In our earlier papers we have found the effect of VLF transmitter signal depression over epicenters of the large earthquakes from observation on the French DEMETER satellite that can be considered as new method of global diagnostics of seismic influence on the ionosphere. At present paper we investigate a possibility VLF signal-ionospheric turbulence interaction using additional characteristic of VLF signal-spectrum broadening. This characteristic is important for estimation of the interaction type: linear or nonlinear scattering. Our main results are the following:
    – There are two zones of increased spectrum broadening, which are centered near magnetic latitudes Φ=±10° and Φ=±40°. Basing on the previous case study research and ground ionosonde registrations, probably it is evidence of nonlinear (active scattering of VLF signal on the ionospheric turbulence. However occurrence rate of spectrum broadening in the middle-latitude area is higher than in the near-equatorial zone (~15–20% in comparison with ~100% in former area that is probably coincides with the rate of ionospheric turbulence.
    – From two years statistics of observation in the selected 3 low-latitude regions and 1 middle-latitude region inside reception area of VLF signal from NWC transmitter we find a correlation of spectrum broadening neither with ion-cyclotron noise (f=150–500 Hz, which possibly means poor representation of the turbulence by the noise due to its mixture with natural ELF emission (which correlates with whistler, nor with magnetic storm activity.
    – We find rather evident correlation of ion-cyclotron frequency noise, VLF signal depression and weak correlation of spectrum broadening with seismicity in the middle-latitude region over Japan. But in the low-latitude regions we do not find such a correlation. Statistical decrease of VLF signal supports our previous case study results. However rather weak spectrum broadening

  20. VLF surface-impedance modelling techniques for coal exploration

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, G.; Thiel, D.; O' Keefe, S. [Central Queensland University, Rockhampton, Qld. (Australia). Faculty of Engineering and Physical Systems

    2000-10-01

    New and efficient computational techniques are required for geophysical investigations of coal. This will allow automated inverse analysis procedures to be used for interpretation of field data. In this paper, a number of methods of modelling electromagnetic surface impedance measurements are reviewed, particularly as applied to typical coal seam geology found in the Bowen Basin. At present, the Impedance method and the finite-difference time-domain (FDTD) method appear to offer viable solutions although both have problems. The Impedance method is currently slightly inaccurate, and the FDTD method has large computational demands. In this paper both methods are described and results are presented for a number of geological targets. 17 refs., 14 figs.

  1. Measurement of phase function of aerosol at different altitudes by CCD Lidar

    Science.gov (United States)

    Sun, Peiyu; Yuan, Ke'e.; Yang, Jie; Hu, Shunxing

    2018-02-01

    The aerosols near the ground are closely related to human health and climate change, the study on which has important significance. As we all know, the aerosol is inhomogeneous at different altitudes, of which the phase function is also different. In order to simplify the retrieval algorithm, it is usually assumed that the aerosol is uniform at different altitudes, which will bring measurement error. In this work, an experimental approach is demonstrated to measure the scattering phase function of atmospheric aerosol particles at different heights by CCD lidar system, which could solve the problem of the traditional CCD lidar system in assumption of phase function. The phase functions obtained by the new experimental approach are used to retrieve the aerosol extinction coefficient profiles. By comparison of the aerosol extinction coefficient retrieved by Mie-scattering aerosol lidar and CCD lidar at night, the reliability of new experimental approach is verified.

  2. Directional spectrum of ocean waves from array measurements using phase/time/path difference methods

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, A.A.; Sarma, Y.V.B.; Menon, H.B.

    Wave direction has for the first time been consistently, accurately and unambiguously evaluated from array measurements using the phase/time/path difference (PTPD) methods of Esteva in case of polygonal arrays and Borgman in case of linear arrays...

  3. Effect of atomic initial phase difference on spontaneous emission of an atom embedded in photonic crystal

    International Nuclear Information System (INIS)

    Bing, Zhang; Xiu-Dong, Sun; Xiang-Qian, Jiang

    2010-01-01

    We investigate the effect of initial phase difference between the two excited states of a V-type three-level atom on its steady state behaviour of spontaneous emission. A modified density of modes is introduced to calculate the spontaneous emission spectra in photonic crystal. Spectra in free space are also shown to compare with that in photonic crystal with different relative positions of the excited levels from upper band-edge frequency. It is found that the initial phase difference plays an important role in the quantum interference property between the two decay channels. For a zero initial phase, destructive property is presented in the spectra. With the increase of initial phase difference, quantum interference between the two decay channels from upper levels to ground level turns to be constructive. Furthermore, we give an interpretation for the property of these spectra. (atomic and molecular physics)

  4. The Effect of Different Phases of Synchrony on Pain Threshold in a Drumming Task

    Directory of Open Access Journals (Sweden)

    Philip Sullivan

    2017-06-01

    Full Text Available Behavioral synchrony has been linked to endorphin activity (Cohen et al., 2010; Sullivan and Rickers, 2013; Sullivan et al., 2014; Tarr et al., 2015, 2016; Weinstein et al., 2016. This has been called the synchrony effect. Synchrony has two dominant phases of movement; in-phase and anti-phase. The majority of research investigating synchrony’s effect on endorphin activity has focused on in-phase synchrony following vigorous activities. The only research to investigate the effects of anti-phase synchrony on endorphin activity found that anti-phase synchronized rowing did not produce the synchrony effect (Sullivan et al., 2014. Anti-phase synchrony, however, is counter-intuitive to the sport of rowing and may have interfered with the synchrony effect. This study investigated the effect of anti-phase synchrony on endorphin activity in a different task (i.e., drumming. University students (n = 30 were asked to drum solo and in in-phase and anti-phase pairs for 3 min. Pain threshold was assessed as an indirect indicator of endorphin activity prior to and following the task. Although the in-phase synchrony effect was not found, a repeated measures ANOVA found that there was a significant difference in pain threshold change among the three conditions [F(2,24 = 4.10, = 0.255, p < 0.05. Post hoc t-tests showed that the anti-phase condition had a significantly greater pain threshold change than both the solo and in-phase conditions at p < 0.05. This is the first time that anti-phase synchrony has been shown to produce the synchrony effect. Because anti-phase drumming may have required more attention between partners than in-phase synchrony, it may have affected self-other merging (Tarr et al., 2014. These results support Tarr et al.’s (2014 model that multiple mechanisms account for the effect of synchrony on pain threshold, and suggest that different characteristics of the activity may influence the synchrony effect.

  5. Comparison of phase-constrained parallel MRI approaches: Analogies and differences.

    Science.gov (United States)

    Blaimer, Martin; Heim, Marius; Neumann, Daniel; Jakob, Peter M; Kannengiesser, Stephan; Breuer, Felix A

    2016-03-01

    Phase-constrained parallel MRI approaches have the potential for significantly improving the image quality of accelerated MRI scans. The purpose of this study was to investigate the properties of two different phase-constrained parallel MRI formulations, namely the standard phase-constrained approach and the virtual conjugate coil (VCC) concept utilizing conjugate k-space symmetry. Both formulations were combined with image-domain algorithms (SENSE) and a mathematical analysis was performed. Furthermore, the VCC concept was combined with k-space algorithms (GRAPPA and ESPIRiT) for image reconstruction. In vivo experiments were conducted to illustrate analogies and differences between the individual methods. Furthermore, a simple method of improving the signal-to-noise ratio by modifying the sampling scheme was implemented. For SENSE, the VCC concept was mathematically equivalent to the standard phase-constrained formulation and therefore yielded identical results. In conjunction with k-space algorithms, the VCC concept provided more robust results when only a limited amount of calibration data were available. Additionally, VCC-GRAPPA reconstructed images provided spatial phase information with full resolution. Although both phase-constrained parallel MRI formulations are very similar conceptually, there exist important differences between image-domain and k-space domain reconstructions regarding the calibration robustness and the availability of high-resolution phase information. © 2015 Wiley Periodicals, Inc.

  6. Correlation of Solar X-ray Flux and SID Modified VLF Signal Strength

    Science.gov (United States)

    2015-03-26

    Motivation ...……………………………………………………………………1-1 Background …………………………………………………………………….1-1 Research Objectives ……………………………………………………………1-3 II...SOLAR X-RAY FLUX AND SID MODIFIED VLF SIGNAL STRENGTH I. Introduction 1.1 Motivation The ionosphere greatly influences long wave radio...accomplished by a research group from Cambridge in the late 1940s. The group recorded the 16 kHz signal of the transmitter in Rugby , England, with the call

  7. Unexpected very low frequency (VLF) radio events recorded by the ionospheric satellite DEMETER

    Czech Academy of Sciences Publication Activity Database

    Parrot, M.; Berthelier, J. J.; Blecki, J.; Brochot, J. Y.; Hobara, Y.; Lagoutte, D.; Lebreton, J. P.; Němec, F.; Onishi, T.; Pincon, J. L.; Píša, David; Santolík, Ondřej; Sauvaud, J. A.; Slominska, E.

    2015-01-01

    Roč. 36, č. 3 (2015), s. 483-511 ISSN 0169-3298 R&D Projects: GA ČR(CZ) GA14-31899S; GA MŠk LH12231 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100421206; Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100421206 Institutional support: RVO:68378289 Keywords : ionosphere * natural and man-made VLF radio emissions * anomalies Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.622, year: 2015 http://link.springer.com/article/10.1007%2Fs10712-015-9315-5

  8. S-phase cell distribution in the small intestine irradiated at different times of the day. 2. Recovery phase

    Energy Technology Data Exchange (ETDEWEB)

    Becciolini, A; Balzi, M; Cremonini, D; Fabbrica, D [Florence Univ. (Italy). Ist. di Radiologia

    1983-01-01

    Modifications occurring during recovery in the small intestine of animals exposed to the same radiation dose given at different times of the day were evaluated. S-phase cell distribution along the crypts and invertase activity were evaluated to ascertain the functional capacity of epithelial cells. In animals killed between 5 and 6 days after exposure, S-phase cell distribution and functional conditions tended towards normality although recovery was not complete. Labelled cells occurred also at villus junctions, demonstrating limitation in size of the differentiating compartment. This was confirmed by reduced activity of the brush border enzymes. Animals irradiated at the end of the dark period recovered more quickly and efficiently. In this group, labelled cell distribution was almost the same as in the controls starting from 120 h, and invertase activity was also closer to the controls than in any other group.

  9. The effect of phase difference between powered electrodes on RF plasmas

    International Nuclear Information System (INIS)

    Proschek, M; Yin, Y; Charles, C; Aanesland, A; McKenzie, D R; Bilek, M M; Boswell, R W

    2005-01-01

    This paper presents the results of measurements carried out on plasmas created in five different RF discharge systems. These systems all have two separately powered RF (13.56 MHz) electrodes, but differ in overall size and in the geometry of both vacuum chambers and RF electrodes or antennae. The two power supplies were synchronized with a phase-shift controller. We investigated the influence of the phase difference between the two RF electrodes on plasma parameters and compared the different system geometries. Single Langmuir probes were used to measure the plasma parameters in a region between the electrodes. Floating potential and ion density were affected by the phase difference and we found a strong influence of the system geometry on the observed phase difference dependence. Both ion density and floating potential curves show asymmetries around maxima and minima. These asymmetries can be explained by a phase dependence of the time evolution of the electrode-wall coupling within an RF-cycle resulting from the asymmetric system geometry

  10. Respiratory functions in asthmatic and normal women during different phases of menstrual cycle

    International Nuclear Information System (INIS)

    Arora, D.B.; Sandhu, P.K.; Dhillon, S.; Arora, A.

    2015-01-01

    Menstrual cycle is an integral part of life of women. There is widespread agreement that changes in the levels of oestrogen and progesterone associated with menstrual cycle also affect different systems of the body besides reproductive system. Levels of oestrogen and progesterone are maximum in the secretory phase and minimum just before the menstruation .Bronchial asthma is one of the commonest chronic respiratory diseases. Premenstrual worsening of asthma symptoms has been reported to affect 33-40% of asthmatic women. This exacerbation of asthma symptoms has been correlated with the oestrogen and progesterone levels. The association between menstrual cycle and lung functions in normal females has also been recognised. The pathophysiology of this process is still not proved. The purpose of our study was to confirm the probable effects of the female hormones on lung functions in normal and asthmatic women in different phases of menstrual cycle and to compare them. Methods: The study was done on 40 normal and 40 asthmatic females in the age group of 15-45 years. Pulmonary function tests were done in three phases of menstrual cycle i.e. follicular, secretory and menstrual in all the subjects. Results: The mean value of lung functions, i.e., FVC, FEV, PEFR, FEF25-75%, FEF 200-1200 were significantly lower in asthmatic females than normal ones (p<0.01) in all three phases. The lung functions of both asthmatic and non-asthmatic females in secretory phase were significantly higher than in menstrual phase (p<0.005). The PFTs in menstrual phase were even lower than the follicular phase (p<0.04). Conclusion: Respiratory parameters of both asthmatic and non-asthmatic women in reproductive age group show significant variation in different phases of menstrual cycle. The smooth muscle relaxant effect of progesterone and probably oestrogen might have contributed to it. The lung function parameters in asthmatics were of lower value compared to normal women. (author)

  11. Selectivity differences of water-soluble vitamins separated on hydrophilic interaction stationary phases.

    Science.gov (United States)

    Yang, Yuanzhong; Boysen, Reinhard I; Hearn, Milton T W

    2013-06-01

    In this study, the retention behavior and selectivity differences of water-soluble vitamins were evaluated with three types of polar stationary phases (i.e. an underivatized silica phase, an amide phase, and an amino phase) operated in the hydrophilic interaction chromatographic mode with ESI mass spectrometric detection. The effects of mobile phase composition, including buffer pH and concentration, on the retention and selectivity of the vitamins were investigated. In all stationary phases, the neutral or weakly charged vitamins exhibited very weak retention under each of the pH conditions, while the acidic and more basic vitamins showed diverse retention behaviors. With the underivatized silica phase, increasing the salt concentration of the mobile phase resulted in enhanced retention of the acidic vitamins, but decreased retention of the basic vitamins. These observations thus signify the involvement of secondary mechanisms, such as electrostatic interaction in the retention of these analytes. Under optimized conditions, a baseline separation of all vitamins was achieved with excellent peak efficiency. In addition, the effects of water content in the sample on retention and peak efficiency were examined, with sample stacking effects observed when the injected sample contained a high amount of water. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Gyrator transform of Gaussian beams with phase difference and generation of hollow beam

    Science.gov (United States)

    Xiao, Zhiyu; Xia, Hui; Yu, Tao; Xie, Ding; Xie, Wenke

    2018-03-01

    The optical expression of Gaussian beams with phase difference, which is caused by gyrator transform (GT), has been obtained. The intensity and phase distribution of transform Gaussian beams are analyzed. It is found that the circular hollow vortex beam can be obtained by overlapping two GT Gaussian beams with π phase difference. The effect of parameters on the intensity and phase distributions of the hollow vortex beam are discussed. The results show that the shape of intensity distribution is significantly influenced by GT angle α and propagation distance z. The size of the hollow vortex beam can be adjusted by waist width ω 0. Compared with previously reported results, the work shows that the hollow vortex beam can be obtained without any model conversion of the light source.

  13. Different phases of a system of hard rods on three dimensional cubic lattice

    Science.gov (United States)

    Vigneshwar, N.; Dhar, Deepak; Rajesh, R.

    2017-11-01

    We study the different phases of a system of monodispersed hard rods of length k on a cubic lattice, using an efficient cluster algorithm able to simulate densities close to the fully-packed limit. For k≤slant 4 , the system is disordered at all densities. For k=5, 6 , we find a single density-driven transition, from a disordered phase to high density layered-disordered phase, in which the density of rods of one orientation is strongly suppressed, breaking the system into weakly coupled layers. Within a layer, the system is disordered. For k ≥slant 7 , three density-driven transitions are observed numerically: isotropic to nematic to layered-nematic to layered-disordered. In the layered-nematic phase, the system breaks up into layers, with nematic order in each layer, but very weak correlation between the ordering directions of different layers. We argue that the layered-nematic phase is a finite-size effect, and in the thermodynamic limit, the nematic phase will have higher entropy per site. We expect the systems of rods in four and higher dimensions will have a qualitatively similar phase diagram.

  14. A discussion of hyperbolicity in CATHENA 4. Virtual mass and phase-to-interface pressure differences

    International Nuclear Information System (INIS)

    Aydemir, Nusret U.

    2012-01-01

    It is well known that the one-dimensional equations of motion for two-phase flow are non-hyperbolic. Non-hyperbolicity can lead to numerical instabilities, destroying the solution. However, researchers in the last few decades were able to show that inclusion of virtual mass and/or phase-to-interface pressure differences in the momentum equations successfully render the equations of motion hyperbolic. In the present paper, the effect of including virtual mass and phase-to-interface pressure terms in the momentum equations on the hyperbolicity of the two-phase model in the CATHENA 4 code is discussed. The study is motivated by the fact that the inclusion of either model has been shown in the open literature to lead to a hyperbolic system separately. However, no known study exists that examine hyperbolicity in the presence of both these terms in the momentum equations. In this work, both terms are considered in the model equations simultaneously and their implications on the hyperbolicity of the two-phase model are discussed. Specifically, it is shown that in the case of mixed flow, there is a distinct region of non-hyperbolicity that developers need to be aware of when their equations include both the virtual mass and the phase-to-interface terms. Selecting the coefficients of phase-to-interface pressure difference terms properly ensures that the equations are hyperbolic for a wide range of conditions. (orig.)

  15. Two different mechanisms support selective attention at different phases of training.

    Science.gov (United States)

    Itthipuripat, Sirawaj; Cha, Kexin; Byers, Anna; Serences, John T

    2017-06-01

    Selective attention supports the prioritized processing of relevant sensory information to facilitate goal-directed behavior. Studies in human subjects demonstrate that attentional gain of cortical responses can sufficiently account for attention-related improvements in behavior. On the other hand, studies using highly trained nonhuman primates suggest that reductions in neural noise can better explain attentional facilitation of behavior. Given the importance of selective information processing in nearly all domains of cognition, we sought to reconcile these competing accounts by testing the hypothesis that extensive behavioral training alters the neural mechanisms that support selective attention. We tested this hypothesis using electroencephalography (EEG) to measure stimulus-evoked visual responses from human subjects while they performed a selective spatial attention task over the course of ~1 month. Early in training, spatial attention led to an increase in the gain of stimulus-evoked visual responses. Gain was apparent within ~100 ms of stimulus onset, and a quantitative model based on signal detection theory (SDT) successfully linked the magnitude of this gain modulation to attention-related improvements in behavior. However, after extensive training, this early attentional gain was eliminated even though there were still substantial attention-related improvements in behavior. Accordingly, the SDT-based model required noise reduction to account for the link between the stimulus-evoked visual responses and attentional modulations of behavior. These findings suggest that training can lead to fundamental changes in the way attention alters the early cortical responses that support selective information processing. Moreover, these data facilitate the translation of results across different species and across experimental procedures that employ different behavioral training regimes.

  16. Two different mechanisms support selective attention at different phases of training

    Science.gov (United States)

    Cha, Kexin; Byers, Anna; Serences, John T.

    2017-01-01

    Selective attention supports the prioritized processing of relevant sensory information to facilitate goal-directed behavior. Studies in human subjects demonstrate that attentional gain of cortical responses can sufficiently account for attention-related improvements in behavior. On the other hand, studies using highly trained nonhuman primates suggest that reductions in neural noise can better explain attentional facilitation of behavior. Given the importance of selective information processing in nearly all domains of cognition, we sought to reconcile these competing accounts by testing the hypothesis that extensive behavioral training alters the neural mechanisms that support selective attention. We tested this hypothesis using electroencephalography (EEG) to measure stimulus-evoked visual responses from human subjects while they performed a selective spatial attention task over the course of ~1 month. Early in training, spatial attention led to an increase in the gain of stimulus-evoked visual responses. Gain was apparent within ~100 ms of stimulus onset, and a quantitative model based on signal detection theory (SDT) successfully linked the magnitude of this gain modulation to attention-related improvements in behavior. However, after extensive training, this early attentional gain was eliminated even though there were still substantial attention-related improvements in behavior. Accordingly, the SDT-based model required noise reduction to account for the link between the stimulus-evoked visual responses and attentional modulations of behavior. These findings suggest that training can lead to fundamental changes in the way attention alters the early cortical responses that support selective information processing. Moreover, these data facilitate the translation of results across different species and across experimental procedures that employ different behavioral training regimes. PMID:28654635

  17. Susceptibility of Hep3B cells in different phases of cell cycle to tBid.

    Science.gov (United States)

    Ma, Shi-Hong; Chen, George G; Ye, Caiguo; Leung, Billy C S; Ho, Rocky L K; Lai, Paul B S

    2011-01-01

    tBid is a pro-apoptotic molecule. Apoptosis inducers usually act in a cell cycle-specific fashion. The aim of this study was to elucidate whether effect of tBid on hepatocellular carcinoma (HCC) Hep3B cells was cell cycle phase specific. We synchronized Hep3B cells at G0/G1, S or G2/M phases by chemicals or flow sorting and tested the susceptibility of the cells to recombinant tBid. Cell viability was measured by MTT assay and apoptosis by TUNEL. The results revealed that tBid primarily targeted the cells at G0/G1 phase of cell cycle, and it also increased the cells at the G2/M phase. 5-Fluorouracil (5-FU), on the other hand, arrested Hep3B cells at the G0/G1 phase, but significantly reduced cells at G2/M phase. The levels of cell cycle-related proteins and caspases were altered in line with the change in the cell cycle. The combination of tBid with 5-FU caused more cells to be apoptotic than either agent alone. Therefore, the complementary effect of tBid and 5-FU on different phases of the cell cycle may explain their synergistric effect on Hep3B cells. The elucidation of the phase-specific effect of tBid points to a possible therapeutic option that combines different phase specific agents to overcome resistance of HCC. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Hemispheric Lateralization of Event-Related Brain Potentials in Different Processing Phases during Unimanual Finger Movements

    Directory of Open Access Journals (Sweden)

    Yi-Wen Li

    2008-04-01

    Full Text Available Previous functional MRI and brain electrophysiology studies have studied the left-right differences during the tapping tasks and found that the activation of left hemisphere was more significant than that of right hemisphere. In this study, we wanted to delineate this lateralization phenomenon not only in the execution phase but also in other processing phases, such as early visual, pre-executive and post-executive phases. We have designed a finger-tapping task to delineate the left-right differences of event related potentials (ERPs to right finger movement in sixteen right handed college students. The mean amplitudes of ERPs were analyzed to examine the left-right dominance of cortical activity in the phase of early visual process (75-120ms, pre-execution (175-260ms, execution (310-420ms and post-execution (420-620ms. In the execution phase, ERPs at the left electrodes were significantly more pronounced than those at the right electrodes (F3 > F4, C3 > C4, P3 > P4, O1 > O2 under the situation without comparing the central electrodes (Fz, Cz, Pz, and Oz. No difference was found between left and right electrodes in other three phases except the C3 electrode still showed more dominant than C4 in the pre- and post-execution phase. In conclusion, the phenomenon of brain lateralization occur major in the execution phase. The central area also showed the lateralization in the pre- and post-execution to demonstrate its unique lateralized contributions to unilateral simple finger movements.

  19. Opto-electronic properties of bismuth oxide films presenting different crystallographic phases

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Celia L. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, UNAM, Unidad de Posgrado, Edificio C, Piso 1, Zona Cultural de CU, México, D.F. 04510 (Mexico); Depablos-Rivera, Osmary, E-mail: osmarydep@yahoo.com [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, UNAM, Unidad de Posgrado, Edificio C, Piso 1, Zona Cultural de CU, México, D.F. 04510 (Mexico); Silva-Bermudez, Phaedra [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Instituto Nacional de Rehabilitación, Calz. México Xochimilco No. 289 Col. Arenal de Guadalupe, C.P.14389, Ciudad de México, D.F. (Mexico); Muhl, Stephen [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Zeinert, Andreas; Lejeune, Michael; Charvet, Stephane; Barroy, Pierre [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex 1 (France); Camps, Enrique [Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, kilómetro 36.5. La Marquesa, Municipio de Ocoyoacac, CP 52750, Estado de México (Mexico); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico)

    2015-03-02

    The optical, electrical and structural properties of bismuth oxide thin films deposited by radio frequency reactive magnetron sputtering were studied. The Bi{sub 2}O{sub 3} thin films were grown on Si and glass substrates under different power and substrate temperatures in an oxygen-enriched plasma leading to films with different crystalline phase as evidenced by X-ray diffraction and Raman spectroscopy. The optical properties of the films were measured using ellipsometric spectroscopy and optical transmission spectra. In order to parameterize the optical dispersion functions (n, k) of the films, the Tauc–Lorentz dispersion model was used. The optical bandgap was then assessed by different methods and the results are compared to the thermal variations of the electrical resistivity of the films. It was found that the refractive index, extinction coefficient and optical gap strongly depend on the deposition conditions and the crystalline phase; the fluorite defect cubic δ-Bi{sub 2}O{sub 3} phase showed the lowest optical gap and lower resistivity. - Highlights: • Different bismuth oxide phases were obtained by sputtering. • The power and substrate temperature were the two key parameters. • Room temperature delta-Bi{sub 2}O{sub 3} thin films were obtained. • The optical bandgap was around 1.5 and 2.2 eV, depending on the phase. • The bismuth oxide films presented activation energies around 1 eV.

  20. Opto-electronic properties of bismuth oxide films presenting different crystallographic phases

    International Nuclear Information System (INIS)

    Gomez, Celia L.; Depablos-Rivera, Osmary; Silva-Bermudez, Phaedra; Muhl, Stephen; Zeinert, Andreas; Lejeune, Michael; Charvet, Stephane; Barroy, Pierre; Camps, Enrique; Rodil, Sandra E.

    2015-01-01

    The optical, electrical and structural properties of bismuth oxide thin films deposited by radio frequency reactive magnetron sputtering were studied. The Bi 2 O 3 thin films were grown on Si and glass substrates under different power and substrate temperatures in an oxygen-enriched plasma leading to films with different crystalline phase as evidenced by X-ray diffraction and Raman spectroscopy. The optical properties of the films were measured using ellipsometric spectroscopy and optical transmission spectra. In order to parameterize the optical dispersion functions (n, k) of the films, the Tauc–Lorentz dispersion model was used. The optical bandgap was then assessed by different methods and the results are compared to the thermal variations of the electrical resistivity of the films. It was found that the refractive index, extinction coefficient and optical gap strongly depend on the deposition conditions and the crystalline phase; the fluorite defect cubic δ-Bi 2 O 3 phase showed the lowest optical gap and lower resistivity. - Highlights: • Different bismuth oxide phases were obtained by sputtering. • The power and substrate temperature were the two key parameters. • Room temperature delta-Bi 2 O 3 thin films were obtained. • The optical bandgap was around 1.5 and 2.2 eV, depending on the phase. • The bismuth oxide films presented activation energies around 1 eV

  1. Measurements of VLF-particle interactions at the South Atlantic Magnetic Anomaly on board a Brazilian geophysical satellite

    International Nuclear Information System (INIS)

    Gonzalez, W.D.; Pinto Junior, O.; Dutra, S.L.G.; Takahashi, H.

    1988-01-01

    A summary of the proposal for measurements of VLF wave-particle interactions, expected to occur at the South Atlantic magnetic anomaly, to be carried out on board a Brazilian geophysical satellite, will be presented. The expected domain of such interactions refers to electromagnetic VLF waves and to energetic-relativistic inner belt electrons, pitch angle diffusing into the atmosphere via cyclotron resonances. The detectors involve a tri-axial search coil magnetometer and a surface barrier silicon telescope. A modified and preliminary version of this proposed experiment will be carried out on board long duration balloon flights, well before the beginning of the intended satellite measurements. For the ballon flights the particle detector will be replaced by an x-ray detector, which can also monitor parameters related to the electron precipitation. (author) [pt

  2. Phase transition of the nucleon-antinucleon plasma at different ratios

    International Nuclear Information System (INIS)

    Delfino, A.; Jansen, M.; Timoteo, V. S.

    2008-01-01

    We investigate phase transitions for the Walecka model at very high temperatures. As is well known, depending on the parametrization of this model and for the particular case of a zero chemical potential (μ), a first-order phase transition is possible [J. Theis, G. Graebner, G. Buchwald, J. A. Maruhn, W. Greiner, H. Stocker, and J. Polonyi, Phys. Rev. D 28, 2286 (1983)]. We investigate this model for the case in which μ≠0. It turns out that, in this situation, phases with different values of antinucleon-nucleon ratios and net baryon densities may coexist. We present the temperature versus antinucleon-nucleon ratio as well as the temperature versus the net baryon density for the coexistence region. The temperature versus chemical potential phase diagram is also presented

  3. The difference of phase distributions in silicon after indentation with Berkovich and spherical indenters

    International Nuclear Information System (INIS)

    Zarudi, I.; Zhang, L.C.; Cheong, W.C.D.; Yu, T.X.

    2005-01-01

    This study analyses the microstructure of monocrystalline silicon after indentation with a Berkovich and spherical indenter. Transmission electron microscopy on cross section view samples was used to explore the detailed distributions of various phases in the subsurfaces of indented silicon. It was found that an increase of the P max would promote the growth of the crystalline R8/BC8 phase at the bottom of the deformation zone. Microcracks were always generated in the range of the P max studied. It was also found that the deformation zones formed by the Berkovich and spherical indenters have very different phase distribution characteristics. A molecular dynamics simulation and finite element analysis supported the experimental observations and suggested that the distribution of the crystalline phases in the transformation zone after indentation was highly stress-dependent

  4. ELF/VLF wave propagation at subauroral latitudes: Conjugate observation between the ground and Van Allen Probes

    Czech Academy of Sciences Publication Activity Database

    Martinez‐Calderon, C.; Shiokawa, K.; Miyoshi, Y.; Keika, K.; Ozaki, M.; Schofield, I.; Connors, M.; Kletzing, C.; Hanzelka, Miroslav; Santolík, Ondřej; Kurth, W. S.

    2016-01-01

    Roč. 121, č. 6 (2016), s. 5384-5393 ISSN 2169-9380 R&D Projects: GA ČR(CZ) GA14-31899S Institutional support: RVO:68378289 Keywords : QP * conjugate event * VLF/ELF * propagation * time delay * ray tracing Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.733, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2015JA022264/full

  5. Angular-dependent light scattering from cancer cells in different phases of the cell cycle.

    Science.gov (United States)

    Lin, Xiaogang; Wan, Nan; Weng, Lingdong; Zhou, Yong

    2017-10-10

    Cancer cells in different phases of the cell cycle result in significant differences in light scattering properties. In order to harvest cancer cells in particular phases of the cell cycle, we cultured cancer cells through the process of synchronization. Flow cytometric analysis was applied to check the results of cell synchronization and prepare for light scattering measurements. Angular-dependent light scattering measurements of cancer cells arrested in the G1, S, and G2 phases have been performed. Based on integral calculations for scattering intensities from 5° to 10° and from 110° to 150°, conclusions have been reached. Clearly, the sizes of the cancer cells in different phases of the cell cycle dominated the forward scatter. Accompanying the increase of cell size with the progression of the cell cycle, the forward scattering intensity also increased. Meanwhile, the DNA content of cancer cells in every phase of the cell cycle is responsible for light scattering at large scatter angles. The higher the DNA content of cancer cells was, the greater the positive effect on the high-scattering intensity. As expected, understanding the relationships between the light scattering from cancer cells and cell cycles will aid in the development of cancer diagnoses. Also, it may assist in the guidance of antineoplastic drugs clinically.

  6. Parametric excitation of very low frequency (VLF) electromagnetic whistler waves and interaction with energetic electrons in radiation belt

    Science.gov (United States)

    Sotnikov, V.; Kim, T.; Caplinger, J.; Main, D.; Mishin, E.; Gershenzon, N.; Genoni, T.; Paraschiv, I.; Rose, D.

    2018-04-01

    The concept of a parametric antenna in ionospheric plasma is analyzed. Such antennas are capable of exciting electromagnetic radiation fields, specifically the creation of whistler waves generated at the very low frequency (VLF) range, which are also capable of propagating large distances away from the source region. The mechanism of whistler wave generation is considered a parametric interaction of quasi-electrostatic whistler waves (also known as low oblique resonance (LOR) oscillations) excited by a conventional loop antenna. The interaction of LOR waves with quasi-neutral density perturbations in the near field of an antenna gives rise to electromagnetic whistler waves on combination frequencies. It is shown in this work that the amplitude of these waves can considerably exceed the amplitude of whistler waves directly excited by a loop. Additionally, particle-in-cell simulations, which demonstrate the excitation and spatial structure of VLF waves excited by a loop antenna, are presented. Possible applications including the wave-particle interactions to mitigate performance anomalies of low Earth orbit satellites, active space experiments, communication via VLF waves, and modification experiments in the ionosphere will be discussed.

  7. Small airway function changes and its clinical significance of asthma patients in different clinical phases

    Directory of Open Access Journals (Sweden)

    Yan-Hui Zhou

    2016-11-01

    Full Text Available Objective: To observe the small airways function changes of asthmatic patients in different clinical phases and to discuss its clinical significance. Methods: A total of 127 patients diagnosed as asthma were selected randomly and pulmonary function (PF of them was determined by conventional method. Then they were divided into A, B and C group based on PF results. All 34 patients in A group suffered from acute asthma attack for the first time. All 93 patients in B group had been diagnosed as asthma but in remission phase. C Group was regarded as Control group with 20 healthy volunteers. Then FEV1, FEF50%, FEF75% levels of patients in each group were analyzed, and ΔFEV1, ΔFEF75% and ΔFEF50% levels of patients in each group were compared after bronchial dilation test. Results: It was found that most patients in group A and B had abnormal small airways function, and their small airways function was significantly different compared with that of group C (P<0.01. In addition, except for group C, ΔFEF75%,ΔFEF50% levels in A and B group were improved more significantly than ΔFEV1 levels (P<0.01. Conclusions: Asthma patients in acute phase all have abnormal small airways function. Most asthma patients in remission phase also have abnormal small airways function. After bronchial dilation test, whether patients in acute phase or in remission phase, major and small airways function of them are improved, but improvement of small airways function is weaker than that of major airways. This indicates that asthma respiratory tract symptoms in different phases exists all the time and so therapeutic process is needed to perform step by step.

  8. How to Evaluate Phase Differences between Trial Groups in Ongoing Electrophysiological Signals

    Science.gov (United States)

    VanRullen, Rufin

    2016-01-01

    A growing number of studies endeavor to reveal periodicities in sensory and cognitive functions, by comparing the distribution of ongoing (pre-stimulus) oscillatory phases between two (or more) trial groups reflecting distinct experimental outcomes. A systematic relation between the phase of spontaneous electrophysiological signals, before a stimulus is even presented, and the eventual result of sensory or cognitive processing for that stimulus, would be indicative of an intrinsic periodicity in the underlying neural process. Prior studies of phase-dependent perception have used a variety of analytical methods to measure and evaluate phase differences, and there is currently no established standard practice in this field. The present report intends to remediate this need, by systematically comparing the statistical power of various measures of “phase opposition” between two trial groups, in a number of real and simulated experimental situations. Seven measures were evaluated: one parametric test (circular Watson-Williams test), and three distinct measures of phase opposition (phase bifurcation index, phase opposition sum, and phase opposition product) combined with two procedures for non-parametric statistical testing (permutation, or a combination of z-score and permutation). While these are obviously not the only existing or conceivable measures, they have all been used in recent studies. All tested methods performed adequately on a previously published dataset (Busch et al., 2009). On a variety of artificially constructed datasets, no single measure was found to surpass all others, but instead the suitability of each measure was contingent on several experimental factors: the time, frequency, and depth of oscillatory phase modulation; the absolute and relative amplitudes of post-stimulus event-related potentials for the two trial groups; the absolute and relative trial numbers for the two groups; and the number of permutations used for non-parametric testing

  9. Experimental comparison of phase retrieval methods which use intensity distribution at different planes

    International Nuclear Information System (INIS)

    Shevkunov, I A; Petrov, N V

    2014-01-01

    Performance of the three phase retrieval methods that use spatial intensity distributions was investigated in dealing with a task of reconstruction of the amplitude characteristics of the test object. These methods differ both by mathematical models and order of iteration execution. The single-beam multiple-intensity reconstruction method showed the best efficiency in terms of quality of reconstruction and time consumption.

  10. Mid-IR spectra of different conformers of phenylalanine in the gas phase

    NARCIS (Netherlands)

    von Helden, G.; Compagnon, I.; Blom, M. N.; Frankowski, M.; Erlekam, U.; Oomens, J.; Brauer, B.; Gerber, R. B.; Meijer, G.

    2008-01-01

    The experimental mid- and far-IR spectra of six conformers of phenylalanine in the gas phase are presented. The experimental spectra are compared to spectra calculated at the B3LYP and at the MP2 level. The differences between B3LYP and MP2 IR spectra are found to be small. The agreement between

  11. Solvation Dynamics in Different Phases of the Lyotropic Liquid Crystalline System.

    Science.gov (United States)

    Roy, Bibhisan; Satpathi, Sagar; Gavvala, Krishna; Koninti, Raj Kumar; Hazra, Partha

    2015-09-03

    Reverse hexagonal (HII) liquid crystalline material based on glycerol monooleate (GMO) is considered as a potential carrier for drugs and other important biomolecules due to its thermotropic phase change and excellent morphology. In this work, the dynamics of encapsulated water, which plays important role in stabilization and formation of reverse hexagonal mesophase, has been investigated by time dependent Stokes shift method using Coumarin-343 as a solvation probe. The formation of the reverse hexagonal mesophase (HII) and transformation to the L2 phase have been monitored using small-angle X-ray scattering and polarized light microscopy experiments. REES studies suggest the existence of different polar regions in both HII and L2 systems. The solvation dynamics study inside the reverse hexagonal (HII) phase reveals the existence of two different types of water molecules exhibiting dynamics on a 120-900 ps time scale. The estimated diffusion coefficients of both types of water molecules obtained from the observed dynamics are in good agreement with the measured diffusion coefficient collected from the NMR study. The calculated activation energy is found to be 2.05 kcal/mol, which is associated with coupled rotational-translational water relaxation dynamics upon the transition from "bound" to "quasi-free" state. The observed ∼2 ns faster dynamics of the L2 phase compared to the HII phase may be associated with both the phase transformation as well as thermotropic effect on the relaxation process. Microviscosities calculated from time-resolved anisotropy studies infer that the interface is almost ∼22 times higher viscous than the central part of the cylinder. Overall, our results reveal the unique dynamical features of water inside the cylinder of reverse hexagonal and inverse micellar phases.

  12. Transvaginal sonographic evaluation at different menstrual cycle phases in diagnosis of uterine lesions

    Directory of Open Access Journals (Sweden)

    Hajishaiha M

    2011-10-01

    Full Text Available Masomeh Hajishaiha1, Mohammad Ghasemi-rad2, Nazila Karimpour1, Nikol Mladkova3, Farzaneh Boromand11Department of Gynecology, 2Student Research Committee (SRC, Urmia University of Medical Sciences, Urmia, Islamic Republic of Iran; 3Institute of Cell and Molecular Science, London, UKPurpose: Intrauterine lesions (IULs are a common finding in women of reproductive age, particularly infertile women. Transvaginal sonography (TVS is a popular tool for IUL detection, but there are conflicting data with respect to its accuracy.Methods: Five hundred and six women were enrolled into the study. Of these, 496 underwent hysterosalpingography and subsequent TVS six different times during the course of their menstrual cycle. If a lesion was detected, it was further evaluated by sonohysterography (SHG and hysteroscopy.Results: Of 496 women, 41 were shown to have IULs by TVS and those lesions were confirmed in 39 by SHG and hysteroscopy. All 39 lesions were detectable during the ovulatory and early luteal phase (days 16–19 of the menstrual cycle. Accuracy of TVS during different phases was largely dependent on the size of the lesion. TVS falsely detected two lesions and missed fine adhesions in two patients.Conclusion: Accuracy of TVS in detection of IULs is highly dependent on the menstrual cycle phase, with the ovulatory and early luteal phase being the optimal time for this examination.Keywords: menstrual cycle phase, space occupying lesions, transvaginal sonography

  13. Voltage harmonic variation in three-phase induction motors with different coil pitches

    International Nuclear Information System (INIS)

    Deshmukh, Ram; Moses, Anthony John; Anayi, Fatih

    2006-01-01

    A pulse-width modulation (PWM) inverter feeding four different chorded three-phase induction motors was tested for low-order odd harmonic voltage component and efficiency at different loads. Total harmonic distortion (THD) due to 3rd, 5th and 9th harmonics was less in a motor with 160 o coil pitch. Particular harmonic order for each coil pitch was suppressed and the efficiency of a 120 o coil pitch motor was increased by 7.5%

  14. Thunderstorm monitoring with VLF network and super dense meteorological observation system

    Science.gov (United States)

    Takahashi, Yukihiro; Sato, Mitsuteru

    2015-04-01

    It's not easy to understand the inside structure and developing process of thunderstorm only with existing meteorological instruments since its horizontal extent of the storm cell is sometimes smaller than an order of 10 km while one of the densest ground network in Japan, AMEDAS, consists of sites located every 17 km in average and the resolution of meteorological radar is 1-2 km in general. Even the X-band radar realizes the resolution of 250 m or larger. Here we suggest a thunderstorm monitoring system consisting of the network of VLF radio wave receivers and the super dense meteorological observation system with simple and low cost plate-type sensors that can be used for measurement both of raindrop and vertical electric field change caused by cloud-to-ground lightning discharge, adding to basic equipments for meteorological measurements. The plate-type sensor consists of two aluminum plates with a diameter of 10-20 cm. We carried out an observation campaign in summer of 2013 in the foothills of Mt. Yastugatake, Yamanashi and Nagano prefectures in Japan, installing 6 plate-type sensors at a distance of about 4 km. Horizontal location, height and charge amount of each lightning discharge are estimated successfully based on the information of electric field changes at several observing sites. Moreover, it was found that the thunderstorm has a very narrow structure smaller than 300 m that cannot be measured by any other ways, counting the positive and negative pulses caused by attachment of raindrop to the sensor plate, respectively. We plan to construct a new super dense observation network in the north Kanto region, Japan, where the lightning activity is most prominent in summer Japan and surrounded by our VLF systems developed for detecting sferics from lightning discharge, distributing more than several tens of sensors at every 4 km or shorter, such as an order of 100 m at minimum. This kind of new type network will reveal the unknown fine structures of

  15. The Phase Envelope of Multicomponent Mixtures in the Presence of a Capillary Pressure Difference

    DEFF Research Database (Denmark)

    Sandoval Lemus, Diego Rolando; Yan, Wei; Michelsen, Michael Locht

    2016-01-01

    for test mixtures with wide ranges of compositions at different capillary radii and vapor fractions. The calculation results show that the phase envelope changes everywhere except at the critical point. The bubble point and the lower branch of the dew point show a decrease in the saturation pressure......, whereas the upper branch of the dew point shows an increase. The cricondentherm is shifted to a higher temperature. We also presented a mathematical analysis of the phase envelope shift due to capillary pressure based on linear approximations. The resulting linear approximation equations can predict...... the magnitude of shift, and the approximation is close for the change in the bubble point pressure....

  16. Radioautographic analysis of changes in different phases of cell kinetics in murine oral mucosa

    International Nuclear Information System (INIS)

    Park, Chang Suck; You, Dong Soo

    1983-01-01

    The age related changes in the life cycle of the progenitor cell population of murine oral epithelia was studied. Using radioautographic methods which have been adopted in previous cell cycle studies, the age-related changes of different phases in renewing cells of the palatal, buccal and lingual mucosae were determined. The results confirm published findings on cell cycle changes of epithelia with aging and illustrated further that mitotic phases which has hither to been considered stationary, also changes with aging. The major parts revealed by this study are as follows: 1. The basal progenitor cells in different regions of oral mucosa have different generation times. 2. The basal cell cycle time increases as a function of aging and the region most affected by aging appears to be the epithelium of the cheek. 3. The phases of the cell cycle affected by the process of aging are in increasing order of magnitude: M-, S- and G1-phase. 4. The age related change in the number of DNA synthesizing basal progenitor cells occurs at two age periods. Between 1 and 12 months of life it decreases, while from 12 to 20 months it increases.

  17. Experimental analysis of influence of different lubricants types on the multi-phase ironing process

    Directory of Open Access Journals (Sweden)

    Milan Djordjević

    2013-05-01

    Full Text Available This paper is aimed at presenting results of an experimental analysis of the different types of lubricants influence on the multi-phase ironing process. Based on sliding of the metal strip between the two contact elements a special tribological model was adopted. The subject of experimental investigations was variations of the drawing force, contact pressure and the friction coefficient for each type of the applied lubricants. The ironing process was conducted in three-phases at the constant sliding velocity. The objective of this analysis was to compare all the applied lubricants in order to estimate their quality from the point of view of their applicability in the multi-phase ironing process.

  18. EXPERIMENTAL ANALYSIS OF INFLUENCE OF DIFFERENT LUBRICANTS TYPES ON THE MULTI-PHASE IRONING PROCESS

    Directory of Open Access Journals (Sweden)

    Milan Djordjević

    2013-09-01

    Full Text Available This paper is aimed at presenting results of an experimental analysis of the different types of lubricants influence on the multi-phase ironing process. Based on sliding of the metal strip between the two contact elements a special tribological model was adopted. The subject of experimental investigations was variations of the drawing force, contact pressure and the friction coefficient for each type of the applied lubricants. The ironing process was conducted in three-phases at the constant sliding velocity. The objective of this analysis was to compare all the applied lubricants in order to estimate their quality from the point of view of their applicability in the multi-phase ironing process.

  19. Assessment of the chromatographic lipophilicity of eight cephalosporins on different stationary phases.

    Science.gov (United States)

    Dąbrowska, Monika; Starek, Małgorzata; Komsta, Łukasz; Szafrański, Przemysław; Stasiewicz-Urban, Anna; Opoka, Włodzimierz

    2017-04-01

    The retention behaviors were investigated for a series of eight cephalosporins in thin-layer chromatography (TLC) using stationary phases of RP-2, RP-8, RP-18, NH 2 , DIOL, and CN chemically bonded silica gel. Additionally, various binary mobile phases (water/methanol and water/acetone) were used in different volume proportions. The retention behavior of the analyzed molecules was defined by R M0 constant. In addition, reversed phase high performance liquid chromatography (RP-HPLC) was performed in lipophilicity studies by using immobilized artificial membrane (IAM) stationary phase. Obtained chromatographic data (R M0 and logk' IAM ) were correlated with the lipophilicity, expressed as values of the log calculated (logP calc ) and experimental (logP exp(shake-flask) ) partition coefficient. Principal component analysis (PCA) was applied in order to obtain an overview of similarity or dissimilarity among the analyzed compounds. Hierarchical cluster analysis (HCA) was performed to compare the separation characteristics of the applied stationary phases. This study was undertaken to identify the best chromatographic system and chromatographic data processing method to enable the prediction of logP values. A comprehensive chromatographic investigation into the retention of the analyzed cephalosporins revealed a similar behavior on RP-18, RP-8 and CN stationary phases. The weak correlations obtained between experimental and certain computed lipophilicity indices revealed that R M0 and PC1/RM are relevant lipophilicity parameters and the RP-8, CN and RP-18 plates are appropriate stationary phases for lipophilicity investigation, whereas computational approaches still cannot fully replace experimentation. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Stability analysis of single-phase thermosyphon loops by finite difference numerical methods

    International Nuclear Information System (INIS)

    Ambrosini, W.

    1998-01-01

    In this paper, examples of the application of finite difference numerical methods in the analysis of stability of single-phase natural circulation loops are reported. The problem is here addressed for its relevance for thermal-hydraulic system code applications, in the aim to point out the effect of truncation error on stability prediction. The methodology adopted for analysing in a systematic way the effect of various finite difference discretization can be considered the numerical analogue of the usual techniques adopted for PDE stability analysis. Three different single-phase loop configurations are considered involving various kinds of boundary conditions. In one of these cases, an original dimensionless form of the governing equations is proposed, adopting the Reynolds number as a flow variable. This allows for an appropriate consideration of transition between laminar and turbulent regimes, which is not possible with other dimensionless forms, thus enlarging the field of validity of model assumptions. (author). 14 refs., 8 figs

  1. Degradation behavior of Mg-based biomaterials containing different long-period stacking ordered phases

    Science.gov (United States)

    Peng, Qiuming; Guo, Jianxin; Fu, Hui; Cai, Xuecheng; Wang, Yanan; Liu, Baozhong; Xu, Zhigang

    2014-01-01

    Long-period stacking ordered (LPSO) phases play an essential role in the development of magnesium alloys because they have a direct effect on mechanical and corrosion properties of the alloys. The LPSO structures are mostly divided to 18R and 14H. However, to date there are no consistent opinions about their degradation properties although both of them can improve mechanical properties. Herein we have successfully obtained two LPSO phases separately in the same Mg-Dy-Zn system and comparatively investigated the effect of different LPSO phases on degradation behavior in 0.9 wt.% NaCl solution. Our results demonstrate that a fine metastable 14H-LPSO phase in grain interior is more effective to improve corrosion resistance due to the presence of a homogeneous oxidation film and rapid film remediation ability. The outstanding corrosion resistant Mg-Dy-Zn based alloys with a metastable 14H-LPSO phase, coupled with low toxicity of alloying elements, are highly desirable in the design of novel Mg-based biomaterials, opening up a new avenue in the area of bio-Mg.

  2. Alteration of Hormonal Levels in a Rootless Epiphytic Bromeliad in Different Phenological Phases.

    Science.gov (United States)

    Mercier; Endres

    1999-11-01

    Major changes in indole-3-acetic acid (IAA) and cytokinin (CK) levels occur at different phenological phases of Tillandsia recurvata shoots. This epiphytic rootless bromeliad was chosen as suitable material for hormonal analysis because CK synthesis is restricted to the shoots, thus avoiding problems in the interpretation of results caused by translocation and interconversion of CK forms between roots and leaves encountered in plants with both organs. Young plants of T. recurvata have weak apical dominance because side shoots appeared early in development, and branch growth was correlated with a strong increase in the level of zeatin. The flowering phase was characterized by a significant increase in free base CKs, zeatin, and isopentenyladenine compared with the levels found in adult vegetative shoots. In contrast, both free-base CKs declined in the fruiting phenological phase, and the IAA level increased dramatically. It was concluded that in phases characterized by intense organ formation, such as in the juvenile and flowering stages, there was an enhancement of CK content, mainly caused by zeatin, leading to a lower IAA/CK ratio. Higher ratios were correlated with phases that showed no organogenesis, such as adult and fruiting phenologies.

  3. Plasma waves produced by an ion beam: observations by the VLF experiment on Porcupine

    International Nuclear Information System (INIS)

    Jones, D.

    1980-01-01

    Results are presented from the VLF electric field experiments flown on Porcupine flights F3 and F4, which also had ejectable xenon ion sources. The xenon ion beam was found to produce plasma instabilities whose frequencies could be linked to the local proton gyrofrequency fsub(cH + ). The main energy in the instabilities lies at approximately 3kHz for events when the Xe + source is close to the rocket, and at approximately 7kHz when the source is farther away. Theory predicts that these frequencies should be the lower-hybrid-resonance and this implies that Xe + is the dominant ion in the first case and that it is the ambient plasma that dominates later. There is no discernable antenna spin-modulation during the Xe events which indicates that the wave k-vectors are not unidirectional. A theory is cited based on the 'setting up' of the proton cyclotron harmonic waves by the Xe + or O + cyclotron harmonic waves. The second Xe + event on both flights exhibited an, as yet, unexplained harmonic structure related to fsub(cH + )/2. (Auth.)

  4. Verification of Bwo Model of Vlf Chorus Generation Using Magion 5 Data

    Science.gov (United States)

    Titova, E. E.; Kozelov, B. V.; Jiricek, F.; Smilauer, J.; Demekhov, A. G.; Trakhtengerts, V. Yu.

    We present a detailed study of chorus emissions in the magnetosphere detected on- board the Magion 5, when the satellite was at low magnetic latitudes. We determine the frequency sweep rate and the periods of electromagnetic VLF chorus emissions. These results are considered within the concept of the backward wave oscillator (BWO) regime of chorus generation. Comparison of the frequency sweep rate of chorus el- ements shows: (i) There is a correlation between the frequency sweep rates and the chorus amplitudes. The frequency sweep rate increases with chorus amplitude in ac- cord with expectations from the BWO model. (ii) The chorus growth rate, estimated from the frequency sweep rate, is in accord with that inferred from the BWO gener- ation mechanism. (iii) The BWO regime of chorus generation ensures the observed decrease in the frequency sweep rate of the chorus elements with increasing L shell. We also discuss the relationship between the observed periods of chorus elements with the predictions following from the BWO model of chorus generation.

  5. Rocket experiment on spontaneously and artificially stimulated VLF plasma waves in the ionosphere

    International Nuclear Information System (INIS)

    Matsumoto, H.; Miyatake, S.; Kimura, I.

    1975-01-01

    In situ active experiments on the nonlinear wave-wave and wave-particle interactions in the ionospheric plasma were performed by a Japanese sounding rocket K-9M-41. Both spontaneously and artificially stimulated plasma waves in the VLF range were observed. When a large amplitude electron plasma wave was transmitted from the rocket, parametrically excited ion acoustic waves were observed in addition to natural emissions such as whistlers, LHR emissions, and hisslike emissions. It was also found that 'risers' were triggered by the LHR emissions, which seem to be very similar to a phenomenon of the so-called ASE (artificially stimulated emissions). When a slow electron beam with energy lower than 3 eV was ejected from the rocket, a new type of periodic U-shaped discrete emission was observed which was excited through a wave-particle interaction. The frequency of these emissions is lower than the LHR frequency and decreases as the beam energy is increased. Spectrograms of the observed plasma are presented, and some are analyzed theoretically. (auth)

  6. ELF-VLF communications through the Earth Project report for calendar year 1984, revision 1

    Science.gov (United States)

    Buettner, H. M.; Burker, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

    1985-08-01

    We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constant of the rock, the noise characteristics, and the modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

  7. ELF-VLF Communications through the Earth Project report for calendar year 1984. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, H.M.; Burke, G.J.; Didwall, E.M.; Holladay, G.; Lytle, R.J.

    1985-08-01

    We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constant of the rock, the noise characteristics, and the modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

  8. Wavelet analysis of the LF radio signals collected by the European VLF/LF network from July 2009 to April 2011

    Directory of Open Access Journals (Sweden)

    Michael E. Contadakis

    2012-04-01

    Full Text Available

    In 2008, a radio receiver that works in very low frequency (VLF; 20-60 kHz and LF (150-300 kHz bands was developed by an Italian factory. The receiver can monitor 10 frequencies distributed in these bands, with the measurement for each of them of the electric field intensity. Since 2009, to date, six of these radio receivers have been installed throughout Europe to establish a ‘European VLF/LF Network’. At present, two of these are into operation in Italy, and the remaining four are located in Greece, Turkey, Portugal and Romania. For the present study, the LF radio data collected over about two years were analysed. At first, the day-time data and the night-time data were separated for each radio signal. Taking into account that the LF signals are characterized by ground-wave and sky-wave propagation modes, the day-time data are related to the ground wave and the night-time data to the sky wave. In this framework, the effects of solar activity and storm activity were defined in the different trends. Then, the earthquakes with M ≥5.0 that occurred over the same period were selected, as those located in a 300-km radius around each receiver/transmitter and within the 5th Fresnel zone related to each transmitter-receiver path. Where possible, the wavelet analysis was applied on the time series of the radio signal intensity, and some anomalies related to previous earthquakes were revealed. Except for some doubt in one case, success appears to have been obtained in all of the cases related to the 300 km circles in for the ground waves and the sky waves. For the Fresnel cases, success in two cases and one failure were seen in analysing the sky waves. The failure occurred in August/September, and might be related to the disturbed conditions of the ionosphere in summer.

     

  9. Application of coincidence Doppler-broadening spectroscopy to different carbon phases

    International Nuclear Information System (INIS)

    Ito, Y.; Djourelov, N.; Suzuki, T.; Kondo, K.; Ito, Y.; Shantarovich, V.; Onoe, J.

    2004-01-01

    Coincidence Doppler-broadening spectroscopy was applied to C60 and C70 fullerenes and other carbon phases, such as nanotubes and graphites. Remarkable differences were observed in the Doppler-broadening of the positron annihilation γ-rays in these materials, which reflect the different densities distribution of the momentum for electrons annihilated with positrons. This would be caused by the different composition of the π and σ electrons in annihilation with positrons. This result shows the sensitivity of the coincidence Doppler-broadening method to determine the density distribution of electrons sampled by positrons. (orig.)

  10. Evaluation of the pressure difference across the core during PWR-LOCA reflood phase

    International Nuclear Information System (INIS)

    Iguchi, Tadashi; Murao, Yoshio

    1979-03-01

    The flooding rate of the core influences largely cooling of the core during the reflood phase of a PWR-LOCA. Since the void fraction of two-phase flow in the core is important determining the flooding rate, it is essential to examine this void fraction. The void fraction in the core during the reflood phase obtained by experiment was compared with those predicted by the correlations respectively of Akagawa, Nicklin, Zuber, Yeh, Griffice, Behringer and Jhonson. Only Yeh's correlation was found to be usable for the purpose. The pressure difference of the core during the reflood phase was calculated by reflood analyzing code REFLA-1D using Yeh's correlation. Following are the results: (1) During the steady-state period after quenching of the heaters, the prediction agrees within +-15% with the experiment. (2) During the transient period when the quench front is advancing, the prediction is not in agreement with the experiment, the difference being about +-40%. Influence of the advancing quench front upon the void fraction in the core must further be studied. (author)

  11. Sex differences in a landmark environmental re-orientation task only during the learning phase.

    Science.gov (United States)

    Piccardi, Laura; Bianchini, Filippo; Iasevoli, Luigi; Giannone, Gianluca; Guariglia, Cecilia

    2011-10-10

    Sex differences are consistently reported in human navigation. Indeed, to orient themselves during navigation women are more likely to use landmark-based strategies and men Euclidean-based strategies. The difference could be due to selective social pressure, which fosters greater spatial ability in men, or biological factors. And the great variability of the results reported in the literature could be due to the experimental setting more than real differences in ability. In this study, navigational behaviour was assessed by means of a place-learning task in which a modified version of the Morris water maze for humans was used to evaluate sex differences. In using landmarks, sex differences emerged only during the learning phase. Although the men were faster than the women in locating the target position, the differences between the sexes disappeared in delayed recall. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Tempering response to different morphologies of martensite in tensile deformation of dual-phase steel

    International Nuclear Information System (INIS)

    Ahmad, E.; Manzoor, T.; Sarwar, M.; Arif, M.; Hussain, N.

    2011-01-01

    A low alloy steel containing 0.2% C was heat treated with three cycles of heat treatments with the aim to acquire different morphologies of martensite in dual phase microstructure. Microscopic examination revealed that the morphologies consisting of grain boundary growth, scattered laths and bulk form of martensite were obtained. These morphologies have their distinct patterns of distribution in the matrix (ferrite). In tensile properties observations the dual phase steel with bulk morphology of martensite showed minimum of ductility but high tensile strength as compared to other two morphologies. This may be due to poor alignments of bulk martensite particles along tensile axes during deformation. Tempering was employed with various holding times at 550 deg. C to induce ductility in the heat treated material. The tempering progressively increased the ductility by increasing holding time. However, tempering response to strengths and ductilities was different to all three morphologies of martensite. (author)

  13. Gender differences in triple jump phase ratios and arm swing motion of international level athletes

    Directory of Open Access Journals (Sweden)

    Vassilios Panoutsakopoulos

    2016-12-01

    Full Text Available Background: Female triple jumping is a relatively new athletics event. A limited number of researchers have focused on comparing male and female jumpers competing in international events, resulting in scarce findings in the literature regarding gender differences of the determinants of triple jump performance. Objective: The aim of the study was to examine the possible gender differences in the approach step characteristics, the spatiotemporal parameters of the separate phases of the triple jump as performed by athletes participating in sub-elite international events. Methods: The male and female participants of the 2015 European Team Championships triple jump event were recorded with a panning video camera. Approach speed was measured using photocells. Kinematical parameters were extracted using the APAS WIZARD 13.3.0.3 software. The relationships between the examined parameters and the actual triple jump performance were examined with Pearson's correlation analysis. Repeated measures ANOVA and chi-square statistical tests were run to examine the significance of the differences between genders. Results: Approach speed significantly correlated with the actual jumping distance in both males and females (p < .05. Significant gender differences (p < .05 existed concerning basic kinematical parameters. Men were found to have larger average horizontal speed of the 11 m to 1 m segment of the final approach, step length of the final six steps of the approach, step frequency of the final two steps, actual phase distances and percentage distribution of the step. Women, unlike men, used solely single arm swing techniques. No athlete executed the jump using a jump dominated technique. Conclusions: Gender differences in triple jump performance lies upon the kinematical parameters of the final two steps of the approach, the length of the step phase and the support time for the jump. The technique elements of the penultimate step are suggested to

  14. Inter-Individual Differences in Neurobehavioural Impairment following Sleep Restriction Are Associated with Circadian Rhythm Phase

    Science.gov (United States)

    Sletten, Tracey L.; Segal, Ahuva Y.; Flynn-Evans, Erin E.; Lockley, Steven W.; Rajaratnam, Shantha M. W.

    2015-01-01

    Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M) aged 22.5 ± 3.1 (mean ± SD) years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission. Sleep opportunity was restricted to 5 hours time-in-bed at home the night before admission and 3 hours time-in-bed in the laboratory, aligned by wake time. Hourly saliva samples were collected from 5.5 h before until 5 h after the pre-laboratory scheduled bedtime to assess dim light melatonin onset (DLMO) as a marker of circadian phase. Participants completed a 10-min auditory Psychomotor Vigilance Task (PVT), the Karolinska Sleepiness Scale (KSS) and had slow eye movements (SEM) measured by electrooculography two hours after waking. We observed substantial inter-individual variability in neurobehavioural performance, particularly in the number of PVT lapses. Increased PVT lapses (r = -0.468, p circadian phase. When the difference between DLMO and sleep onset was less than 2 hours, individuals were significantly more likely to have at least three attentional lapses the following morning. This study demonstrates that the phase of an individual’s circadian system is an important variable in predicting the degree of neurobehavioural performance impairment in the hours after waking following sleep restriction, and confirms that other factors influencing performance decrements require further investigation. PMID:26043207

  15. Inter-Individual Differences in Neurobehavioural Impairment following Sleep Restriction Are Associated with Circadian Rhythm Phase.

    Directory of Open Access Journals (Sweden)

    Tracey L Sletten

    Full Text Available Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M aged 22.5 ± 3.1 (mean ± SD years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission. Sleep opportunity was restricted to 5 hours time-in-bed at home the night before admission and 3 hours time-in-bed in the laboratory, aligned by wake time. Hourly saliva samples were collected from 5.5 h before until 5 h after the pre-laboratory scheduled bedtime to assess dim light melatonin onset (DLMO as a marker of circadian phase. Participants completed a 10-min auditory Psychomotor Vigilance Task (PVT, the Karolinska Sleepiness Scale (KSS and had slow eye movements (SEM measured by electrooculography two hours after waking. We observed substantial inter-individual variability in neurobehavioural performance, particularly in the number of PVT lapses. Increased PVT lapses (r = -0.468, p < 0.01, greater sleepiness (r = 0.510, p < 0.0001, and more slow eye movements (r = 0.375, p = 0.022 were significantly associated with later DLMO, consistent with participants waking at an earlier circadian phase. When the difference between DLMO and sleep onset was less than 2 hours, individuals were significantly more likely to have at least three attentional lapses the following morning. This study demonstrates that the phase of an individual's circadian system is an important variable in predicting the degree of neurobehavioural performance impairment in the hours after waking following sleep restriction, and confirms that other factors influencing performance decrements require further

  16. The Ionospheric Precursor to the 2011 March 11 Earthquake Based upon Observations Obtained from the Japan-Pacific Subionospheric VLF/LF Network

    Directory of Open Access Journals (Sweden)

    Masashi Hayakawa

    2013-01-01

    Full Text Available By using network observation of subionospheric VLF (very low frequency/LF (low frequency signals in Japan and in Russia, we have found a significant ionospheric perturbation prior to the recent 2011 March 11 Japan earthquake (EQ which occurred at sea proximate to the Tohoku area on the main island (Honshu of Japan was an exceptionally huge plate-type EQ. A remarkable anomaly (with a decrease in the nighttime amplitude and also with enhancement in dispersion was detected on March 5 and 6 along the propagation path from the NLK (Seattle, USA transmitter to Chofu (together with Kochi and Kasugai. We also have observed the corresponding VLF anomaly during a prolonged period of March 1 - 6, with minima in the nighttime amplitude on March 3 and 4 along the path from JJI (Miyazaki, Kyushu to Kamchatka, Russia. This ionospheric perturbation has been discussed extensively with respect to its reliability. (1 How abnormal is this VLF/LF propagation anomaly? (2 What was the temporal evolution of terminator times? (3 Were there any solar-terrestrial effects (especially the effect from geomagnetic storms on the VLF/LF propagation anomaly? (4 The effect of any other EQs and foreshock activities on the VLF/LF anomaly? (5 Were there any correlations with other related phenomena? Finally, (6 are there any other examples of a VLF/LF propagation anomaly for oceanic EQs? We then compared the temporal properties of ionospheric perturbations for this EQ with those of a huge number of inland EQs and compared the corresponding spatial scale with the former result of the same oceanic 2004 Sumatra EQ with nearly the same magnitude. Finally, the generation mechanism of those seismo-ionospheric perturbations is briefly discussed.

  17. Harvesting yeast (Saccharomyces cerevisiae) at different physiological phases significantly affects its functionality in bread dough fermentation.

    Science.gov (United States)

    Rezaei, Mohammad N; Dornez, Emmie; Jacobs, Pieter; Parsi, Anali; Verstrepen, Kevin J; Courtin, Christophe M

    2014-05-01

    Fermentation of sugars into CO2, ethanol and secondary metabolites by baker's yeast (Saccharomyces cerevisiae) during bread making leads to leavening of dough and changes in dough rheology. The aim of this study was to increase our understanding of the impact of yeast on dough related aspects by investigating the effect of harvesting yeast at seven different points of the growth profile on its fermentation performance, metabolite production, and the effect on critical dough fermentation parameters, such as gas retention potential. The yeast cells harvested during the diauxic shift and post-diauxic growth phase showed a higher fermentation rate and, consequently, higher maximum dough height than yeast cells harvested in the exponential or stationary growth phase. The results further demonstrate that the onset of CO2 loss from fermenting dough is correlated with the fermentation rate of yeast, but not with the amount of CO2 that accumulated up to the onset point. Analysis of the yeast metabolites produced in dough yielded a possible explanation for this observation, as they are produced in different levels depending on physiological phase and in concentrations that can influence dough matrix properties. Together, our results demonstrate a strong effect of yeast physiology at the time of harvest on subsequent dough fermentation performance, and hint at an important role of yeast metabolites on the subsequent gas holding capacity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Diurnal Thermal Behavior of Photovoltaic Panel with Phase Change Materials under Different Weather Conditions

    Directory of Open Access Journals (Sweden)

    Jae-Han Lim

    2017-12-01

    Full Text Available The electric power generation efficiency of photovoltaic (PV panels depends on the solar irradiation flux and the operating temperature of the solar cell. To increase the power generation efficiency of a PV system, this study evaluated the feasibility of phase change materials (PCMs to reduce the temperature rise of solar cells operating under the climate in Seoul, Korea. For this purpose, two PCMs with different phase change characteristics were prepared and the phase change temperatures and thermal conductivities were compared. The diurnal thermal behavior of PV panels with PCMs under the Seoul climate was evaluated using a 2-D transient thermal analysis program. This paper discusses the heat flow characteristics though the PV cell with PCMs and the effects of the PCM types and macro-packed PCM (MPPCM methods on the operating temperatures under different weather conditions. Selection of the PCM type was more important than the MMPCM methods when PCMs were used to enhance the performance of PV panels and the mean operating temperature of PV cell and total heat flux from the surface could be reduced by increasing the heat transfer rate through the honeycomb grid steel container for PCMs. Considering the mean operating temperature reduction of 4 °C by PCM in this study, an efficiency improvement of approximately 2% can be estimated under the weather conditions of Seoul.

  19. Discriminating the precipitation phase based on different temperature thresholds in the Songhua River Basin, China

    Science.gov (United States)

    Zhong, Keyuan; Zheng, Fenli; Xu, Ximeng; Qin, Chao

    2018-06-01

    Different precipitation phases (rain, snow or sleet) differ greatly in their hydrological and erosional processes. Therefore, accurate discrimination of the precipitation phase is highly important when researching hydrologic processes and climate change at high latitudes and mountainous regions. The objective of this study was to identify suitable temperature thresholds for discriminating the precipitation phase in the Songhua River Basin (SRB) based on 20-year daily precipitation collected from 60 meteorological stations located in and around the basin. Two methods, the air temperature method (AT method) and the wet bulb temperature method (WBT method), were used to discriminate the precipitation phase. Thirteen temperature thresholds were used to discriminate snowfall in the SRB. These thresholds included air temperatures from 0 to 5.5 °C at intervals of 0.5 °C and the wet bulb temperature (WBT). Three evaluation indices, the error percentage of discriminated snowfall days (Ep), the relative error of discriminated snowfall (Re) and the determination coefficient (R2), were applied to assess the discrimination accuracy. The results showed that 2.5 °C was the optimum threshold temperature for discriminating snowfall at the scale of the entire basin. Due to differences in the landscape conditions at the different stations, the optimum threshold varied by station. The optimal threshold ranged 1.5-4.0 °C, and 19 stations, 17 stations and 18 stations had optimal thresholds of 2.5 °C, 3.0 °C, and 3.5 °C respectively, occupying 90% of all stations. Compared with using a single suitable temperature threshold to discriminate snowfall throughout the basin, it was more accurate to use the optimum threshold at each station to estimate snowfall in the basin. In addition, snowfall was underestimated when the temperature threshold was the WBT and when the temperature threshold was below 2.5 °C, whereas snowfall was overestimated when the temperature threshold exceeded 4

  20. Lower Ionosphere Sensitivity to Solar X-ray Flares Over a Complete Solar Cycle Evaluated From VLF Signal Measurements

    Science.gov (United States)

    Macotela, Edith L.; Raulin, Jean-Pierre; Manninen, Jyrki; Correia, Emília; Turunen, Tauno; Magalhães, Antonio

    2017-12-01

    The daytime lower ionosphere behaves as a solar X-ray flare detector, which can be monitored using very low frequency (VLF) radio waves that propagate inside the Earth-ionosphere waveguide. In this paper, we infer the lower ionosphere sensitivity variation over a complete solar cycle by using the minimum X-ray fluence (FXmin) necessary to produce a disturbance of the quiescent ionospheric conductivity. FXmin is the photon energy flux integrated over the time interval from the start of a solar X-ray flare to the beginning of the ionospheric disturbance recorded as amplitude deviation of the VLF signal. FXmin is computed for ionospheric disturbances that occurred in the time interval of December-January from 2007 to 2016 (solar cycle 24). The computation of FXmin uses the X-ray flux in the wavelength band below 0.2 nm and the amplitude of VLF signals transmitted from France (HWU), Turkey (TBB), and U.S. (NAA), which were recorded in Brazil, Finland, and Peru. The main result of this study is that the long-term variation of FXmin is correlated with the level of solar activity, having FXmin values in the range (1 - 12) × 10-7 J/m2. Our result suggests that FXmin is anticorrelated with the lower ionosphere sensitivity, confirming that the long-term variation of the ionospheric sensitivity is anticorrelated with the level of solar activity. This result is important to identify the minimum X-ray fluence that an external source of ionization must overcome in order to produce a measurable ionospheric disturbance during daytime.

  1. Groundwater resources evaluation in calcareous limestone using geoelectrical and VLF-EM surveys (El Salloum Basin, Egypt)

    Science.gov (United States)

    Zarif, Fardous; Slater, Lee; Mabrouk, Mohamed; Youssef, Ahmed; Al-Temamy, Ayman; Mousa, Salah; Farag, Karam; Robinson, Judy

    2018-01-01

    Understanding and developing groundwater resources in arid regions such as El Salloum basin, along the northwestern coast of Egypt, remains a challenging issue. One-dimensional (1D) electrical sounding (ES), two-dimensional (2D) electrical resistivity imaging (ERI), and very low frequency electromagnetic (VLF-EM) measurements were used to investigate the hydrogeological framework of El Salloum basin with the aim of determining the potential for extraction of potable water. 1D resistivity sounding models were used to delineate geoelectric sections and water-bearing layers. 2D ERI highlighted decreases in resistivity with depth, attributed to clay-rich limestone combined with seawater intrusion towards the coast. A depth of investigation (DOI) index was used to constrain the information content of the images at depths up to 100 m. The VLF-EM survey identified likely faults/fractured zones across the study area. A combined analysis of the datasets of the 1D ES, 2D ERI, and VLF-EM methods identified potential zones of groundwater, the extent of seawater intrusion, and major hydrogeological structures (fracture zones) in El Salloum basin. The equivalent geologic layers suggest that the main aquifer in the basin is the fractured chalky limestone middle Miocene) south of the coastal plain of the study area. Sites likely to provide significant volumes of potable water were identified based on relatively high resistivity and thickness of laterally extensive layers. The most promising locations for drilling productive wells are in the south and southeastern parts of the region, where the potential for potable groundwater increases substantially.

  2. Poisson's ratio and Young's modulus of lipid bilayers in different phases

    Directory of Open Access Journals (Sweden)

    Tayebeh eJadidi

    2014-04-01

    Full Text Available A general computational method is introduced to estimate the Poisson's ratio for membranes with small thickness.In this method, the Poisson's ratio is calculated by utilizing a rescaling of inter-particle distancesin one lateral direction under periodic boundary conditions. As an example for the coarse grained lipid model introduced by Lenz and Schmid, we calculate the Poisson's ratio in the gel, fluid, and interdigitated phases. Having the Poisson's ratio, enable us to obtain the Young's modulus for the membranes in different phases. The approach may be applied to other membranes such as graphene and tethered membranes in orderto predict the temperature dependence of its Poisson's ratio and Young's modulus.

  3. Single phase-change analysis of two different PCMs filled in a heat transfer module

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Gyu; Kang, Chae Dong [Chonbuk National University, Jeonju (Korea, Republic of); Kim, Hyung Kuk [Hyundai Heavy Industries Co., Ulsan (Korea, Republic of)

    2014-07-15

    Phase change material(PCM) is tried to secondary heat source in solar heat pump system. A numerical study of the phase change dominant heat transfer is done with a heat transfer module, which consists of a water path(BRINE), heat transfer plates(HTP), and PCM layers of high-temperature one(HPCM, 78-79 .deg. C) and low-temperature one(LPCM, 28-29 .deg. C). There are five arrangements consisting of BRINE, HTP, HPCM, and LPCM layers in the heat transfer module. The time and heat transfer rate for PCM melting/solidification are compared between arrangements. And the numerical time without convection is compared to the experimental one for melting/solidification. From the numerical analysis, the time for melting/solidification is different to 10 hours, depending on the arrangement.

  4. Selective oxidation of dual phase steel after annealing at different dew points

    Science.gov (United States)

    Lins, Vanessa de Freitas Cunha; Madeira, Laureanny; Vilela, Jose Mario Carneiro; Andrade, Margareth Spangler; Buono, Vicente Tadeu Lopes; Guimarães, Juliana Porto; Alvarenga, Evandro de Azevedo

    2011-04-01

    Hot galvanized steels have been extensively used in the automotive industry. Selective oxidation on the steel surface affects the wettability of zinc on steel and the grain orientation of inhibition layer (Fe-Al-Zn alloy) and reduces the iron diffusion to the zinc layer. The aim of this work is to identify and quantify selective oxidation on the surface of a dual phase steel, and an experimental steel with a lower content of manganese, annealed at different dew points. The techniques employed were atomic force microscopy, X-ray photoelectron spectroscopy, and glow discharge optical emission spectroscopy. External selective oxidation was observed for phosphorus on steel surface annealed at 0 °C dp, and for manganese, silicon, and aluminum at a lower dew point. The concentration of manganese was higher on the dual phase steel surface than on the surface of the experimental steel. The concentration of molybdenum on the surface of both steels increased as the depth increased.

  5. Molecular differences between deuterated and protonated polystyrenes using reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Kayillo, Sindy; Gray, Michael J; Shalliker, R Andrew; Dennis, Gary R

    2005-05-06

    Isotopic substitution is a technique used to highlight particular bonds within a molecule for kinetic, spectroscopic and structure analysis. It is presumed that although some properties such as stretching frequencies will not be the same for substituted analogues, the chemical interactions will not vary appreciably as a function of labelling. Reversed-phase liquid chromatography has been used to demonstrate that there are significant differences between the chromatographic behaviour of a sequence of deuterated and protonated oligomeric polystyrenes. Two-dimensional reversed-phase liquid chromatography was used to show that even the diasteromers of the oligomers (n = 5) have retention mechanisms that are dependent on the subtle changes to the molecular conformation and electronic structure, which are a consequence of deuteration.

  6. Direct phase derivative estimation using difference equation modeling in holographic interferometry

    International Nuclear Information System (INIS)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2014-01-01

    A new method is proposed for the direct phase derivative estimation from a single spatial frequency modulated carrier fringe pattern in holographic interferometry. The fringe intensity in a given row/column is modeled as a difference equation of intensity with spatially varying coefficients. These coefficients carry the information on the phase derivative. Consequently, the accurate estimation of the coefficients is obtained by approximating the coefficients as a linear combination of the predefined linearly independent basis functions. Unlike Fourier transform based fringe analysis, the method does not call for performing the filtering of the Fourier spectrum of fringe intensity. Moreover, the estimation of the carrier frequency is performed by applying the proposed method to a reference interferogram. The performance of the proposed method is insensitive to the fringe amplitude modulation and is validated with the simulation results. (paper)

  7. Preparation of n-tetradecane-containing microcapsules with different shell materials by phase separation method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui [Department of Chemical Engineering, Tsinghua University, Beijing (China); Zhang, Yan; Zhang, Qingwu [Department of Chemical Engineering, China University of Mining and Technology, Beijing (China); Wang, Xin; Zhang, Yinping [Department of Building Science, Tsinghua University, Beijing (China)

    2009-10-15

    Microcapsules for thermal energy storage and heat-transfer enhancement have attracted great attention. Microencapsulation of n-tetradecane with different shell materials was carried out by phase separation method in this paper. Acrylonitrile-styrene copolymer (AS), acrylonitrile-styrene-butadiene copolymer (ABS) and polycarbonate (PC) were used as the shell materials. The structures, morphologies and the thermal capacities of the microcapsules were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The ternary phase diagrams showed the potential encapsulation capabilities of the three shell materials. The effects of the shell/core ratio and the molecular weight of the shell material on the encapsulation efficiency and the thermal capacity of the microcapsules were also discussed. Microcapsules with melting enthalpy > 100 J/g, encapsulation efficiency 66-75%, particle size<1 {mu}m were obtained for all three shell materials. (author)

  8. Simultaneous observations of quasi-periodic ELF/VLF wave emissions and electron precipitation by DEMETER satellite: A case study

    Czech Academy of Sciences Publication Activity Database

    Hayosh, Mykhaylo; Pasmanik, D. L.; Demekhov, A. G.; Santolík, Ondřej; Parrot, M.; Titova, E. E.

    2013-01-01

    Roč. 118, č. 7 (2013), s. 4523-4533 ISSN 2169-9380 R&D Projects: GA ČR(CZ) GAP209/11/2280; GA MŠk LH12231 Institutional support: RVO:68378289 Keywords : quasi-periodic ELF/VLF emission s in the magnetosphere * wave-particle interactions * demeter spacecraft measurements * whistler-mode waves Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.440, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/jgra.50179/abstract

  9. Anomalies in VLF radio signals prior the Abruzzo earthquake (M=6.3) on 6 April 2009

    OpenAIRE

    Rozhnoi, A.; Solovieva, M.; Molchanov, O.; Schwingenschuh, K.; Boudjada, M.; Biagi, P. F.; Maggipinto, T.; Castellana, L.; Ermini, A.; Hayakawa, M.

    2009-01-01

    The VLF/LF radio signals method for studying preseimic activity is applied to the Abruzzo earthquake (M=6.3, 6 April 2009). The data collected by three receivers located in Moscow (Russia), Graz (Austria) and Bari (Italy) at about 3000 km, 1000 km and 500 km from the epicenter were used. The signals received from the Sardinia (20.27 kHz) and the Sicily (45.9 kHz) transmitters, both located in Italy, were compared with those received from the Iceland (37.5 kHz), the Great Bri...

  10. ELF/VLF signatures of sprite-producing lightning discharges observed during the 2005 EuroSprite campaign

    DEFF Research Database (Denmark)

    Greenberg, E.; Price, C.; Yair, Y.

    2009-01-01

    ) discharges had peak current intensities between +8 and +130 kA whereas their charge moment changes (CMC) ranged from 500 to 3500 C km. Furthermore, the peak current reported by the Météorage lightning network are well correlated with the amplitudes of the VLF bursts, while showing poor correlation......%) an ELF transient was not associated with sprite occurrence, suggesting that long continuing current of tens of ms may not always be a necessary condition for sprite production, a finding which influences the estimation of the global sprite rate based on Schumann resonance (SR) measurements....

  11. Are there differences in acute phase inflammation markers regarding the type of heart failure?

    Directory of Open Access Journals (Sweden)

    Jaime Agüero-Ramón-Llin

    2011-09-01

    Full Text Available This study aimed to determine if there are differences in inflammatory markers in the acute phase between systolic heart failure and heart failure with preserved systolic function. One hundred and thirty-one patients with acute heart failure were recruited consecutively. At admission, plasma fibrinogen, Creactive protein, sialic acid, von Willebrand factor, vascular endothelial growth factor, interleukin-6 and NTproBNP were all evaluated. If the ejection fraction was 45% or over patients were included in the HF-PSF group; the remaining patients were included in the SHF group. The HF-PSF patients were older (72±10 vs 63±12 years, P<0.001, presented a higher rate of atrial fibrillation (56.1 vs 21.3%, P<0.001, and had a lower rate of hemoglobin (12.2±2 vs 13.3±2.1 g/dL, P<0.01. No significant differences were observed in the inflammation markers analyzed among SHF and HFPSF groups. In the acute phase of heart failure there is a marked elevation of inflammatory markers but there are no differences in the inflammatory markers analyzed between the two different types of heart failure

  12. Wave-Kinetic Simulations of the Nonlinear Generation of Electromagnetic VLF Waves through Velocity Ring Instabilities

    Science.gov (United States)

    Ganguli, G.; Crabtree, C. E.; Rudakov, L.; Mithaiwala, M.

    2014-12-01

    Velocity ring instabilities are a common naturally occuring magnetospheric phenomenon that can also be generated by man made ionospheric experiments. These instabilities are known to generate lower-hybrid waves, which generally cannot propagte out of the source region. However, nonlinear wave physics can convert these linearly driven electrostatic lower-hybrid waves into electromagnetic waves that can escape the source region. These nonlinearly generated waves can be an important source of VLF turbulence that controls the trapped electron lifetime in the radiation belts. We develop numerical solutions to the wave-kinetic equation in a periodic box including the effects of nonlinear (NL) scattering (nonlinear Landau damping) of Lower-hybrid waves giving the evolution of the wave-spectra in wavenumber space. Simultaneously we solve the particle diffusion equation of both the background plasma particles and the ring ions, due to both linear and nonlinear Landau resonances. At initial times for cold ring ions, an electrostatic beam mode is excited, while the kinetic mode is stable. As the instability progresses the ring ions heat, the beam mode is stabilized, and the kinetic mode destabilizes. When the amplitude of the waves becomes sufficient the lower-hybrid waves are scattered (by either nearly unmagnetized ions or magnetized electrons) into electromagnetic magnetosonic waves [Ganguli et al 2010]. The effect of NL scattering is to limit the amplitude of the waves, slowing down the quasilinear relaxation time and ultimately allowing more energy from the ring to be liberated into waves [Mithaiwala et al. 2011]. The effects of convection out of the instability region are modeled, additionally limiting the amplitude of the waves, allowing further energy to be liberated from the ring [Scales et al., 2012]. Results are compared to recent 3D PIC simulations [Winske and Duaghton 2012].

  13. Very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) investigation for groundwater potential evaluation in a complex geological terrain around the Ijebu-Ode transition zone, southwestern Nigeria

    International Nuclear Information System (INIS)

    Osinowo, Olawale O; Olayinka, A Idowu

    2012-01-01

    Groundwater exploration in either a basement or sedimentary environment is often fairly well defined and focuses on delineating weathered/fractured rocks or saturated formations, respectively. Conversely, unique geological structures, the complex coexistence of different rock types and poorly defined basal/lateral contacts between basement and sedimentary rocks make groundwater development in a geological transition environment very challenging. Ijebu-Ode and its environs lie within such a problematic transition zone, between the Precambrian basement rocks and Cretaceous sediments of the Dahomey Basin, in southwestern Nigeria, where associated acute groundwater development challenges require adequate subsurface information to maximize its groundwater resource potential. This study integrated very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) geophysical prospecting techniques for a detailed terrain study of Ijebu-Ode in order to establish the reasons for the low groundwater resource potential in the area. Thirty five VLF-EM profiles, 140 vertical electrical soundings (VES) and relevant hydrogeological data were acquired along grids and profiles. Data were filtered, inverted and enhanced using appropriate software packages. The current density and geoelectric parameters of the VLF-EM and VES data were employed to generate terrain maps, the conductivity distribution and a subsurface basement model of the study area. Current density plots and geoelectric parameters identified up to three layers in the basement complex terrain which comprised lateritic topsoil, weathered basement and fresh basement rocks. The five layers encountered in the sedimentary terrain were topsoil, a lateritic unit, a dry sandy unit, a saturated sandy unit and fresh basement rocks. The hydraulic conductivity of the thick (3–18 m) lateritic unit was determined to be 1.32 × 10 −5 mm s −1 , while that of the underlying sandy units ranged from 2.65 × 10 −4 to 1

  14. Study of Monte Carlo Simulation Method for Methane Phase Diagram Prediction using Two Different Potential Models

    KAUST Repository

    Kadoura, Ahmad

    2011-06-06

    Lennard‐Jones (L‐J) and Buckingham exponential‐6 (exp‐6) potential models were used to produce isotherms for methane at temperatures below and above critical one. Molecular simulation approach, particularly Monte Carlo simulations, were employed to create these isotherms working with both canonical and Gibbs ensembles. Experiments in canonical ensemble with each model were conducted to estimate pressures at a range of temperatures above methane critical temperature. Results were collected and compared to experimental data existing in literature; both models showed an elegant agreement with the experimental data. In parallel, experiments below critical temperature were run in Gibbs ensemble using L‐J model only. Upon comparing results with experimental ones, a good fit was obtained with small deviations. The work was further developed by adding some statistical studies in order to achieve better understanding and interpretation to the estimated quantities by the simulation. Methane phase diagrams were successfully reproduced by an efficient molecular simulation technique with different potential models. This relatively simple demonstration shows how powerful molecular simulation methods could be, hence further applications on more complicated systems are considered. Prediction of phase behavior of elemental sulfur in sour natural gases has been an interesting and challenging field in oil and gas industry. Determination of elemental sulfur solubility conditions helps avoiding all kinds of problems caused by its dissolution in gas production and transportation processes. For this purpose, further enhancement to the methods used is to be considered in order to successfully simulate elemental sulfur phase behavior in sour natural gases mixtures.

  15. Representation of dynamic interaural phase difference in auditory cortex of awake rhesus macaques.

    Science.gov (United States)

    Scott, Brian H; Malone, Brian J; Semple, Malcolm N

    2009-04-01

    Neurons in auditory cortex of awake primates are selective for the spatial location of a sound source, yet the neural representation of the binaural cues that underlie this tuning remains undefined. We examined this representation in 283 single neurons across the low-frequency auditory core in alert macaques, trained to discriminate binaural cues for sound azimuth. In response to binaural beat stimuli, which mimic acoustic motion by modulating the relative phase of a tone at the two ears, these neurons robustly modulate their discharge rate in response to this directional cue. In accordance with prior studies, the preferred interaural phase difference (IPD) of these neurons typically corresponds to azimuthal locations contralateral to the recorded hemisphere. Whereas binaural beats evoke only transient discharges in anesthetized cortex, neurons in awake cortex respond throughout the IPD cycle. In this regard, responses are consistent with observations at earlier stations of the auditory pathway. Discharge rate is a band-pass function of the frequency of IPD modulation in most neurons (73%), but both discharge rate and temporal synchrony are independent of the direction of phase modulation. When subjected to a receiver operator characteristic analysis, the responses of individual neurons are insufficient to account for the perceptual acuity of these macaques in an IPD discrimination task, suggesting the need for neural pooling at the cortical level.

  16. Characterisation of different single and multilayer films using phase modulated spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Das, N.C.; Bhattacharyya, D.; Thakur, S.

    1998-06-01

    Different single layers and multilayer coatings deposited by e-beam evaporation and r.f. sputtering techniques have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. Measurements have been done on single layers of Cu, Si and ZrO 2 films and on multilayer thin films devices e.g., high reflectivity mirror, beam combiner, beam splitter, narrow band filter etc. consisting of several bilayers of TiO 2 /SiO 2 . The measured Ellipsometry spectra is then fitted with a theoretical spectra generated assuming an appropriate model regarding the sample. The layer thickness and composition have been used as fitting parameters. The optical constants of the substrates have been supplied and a trial dispersion relation have been used for the layers. In case of inhomogeneous layers, trial compositions have been given for the individual components for each layer. The roughness of the layers has been taken into account by assuming the film to be an inhomogeneous mixture of material and voids. The fittings have been done objectively by minimising the squared difference (χ 2 ) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. (author)

  17. Simple markers for subclinical inflammation in the different phases of bipolar affective disorder

    Directory of Open Access Journals (Sweden)

    Mesut Yildiz

    Full Text Available Abstract Background: Recently, a growing number of publications have suggested that the immune-inflammatory system may be involved in the etiology of bipolar disorder (BD. Objective: The aim of this study was to investigate neutrophil-lymphocyte ratio (NLR, platelet-lymphocyte ratio (PLR, and red cell distribution width (RDW in the three different phases of BD patients compared to each other and controls. Methods: One hundred eighty-seven bipolar patients (78 euthymic, 53 manic/hypomanic and 56 depressed, and 62 age and sex matched controls were enrolled. Sociodemographic variables and complete blood count parameters of the patients and the control group were recorded. Results: The groups did not differ from each other on the hematological parameters, except for NLR and RDW. Post-hoc analyses revealed that NLR values were significantly higher in the euthymic and manic/hypomanic bipolar groups compared to control group. In addition, post-hoc analyses revealed that RDW values were significantly higher in the manic/hypomanic bipolar group relative to the control group. Discussion: Longitudinal studies evaluating the levels of inflammatory markers in the early phases of the disorder, and their relationship with the development of different episodes and medical comorbidities may be useful to understand the role of inflammation in BD.

  18. Differences in hamstring activation characteristics between the acceleration and maximum-speed phases of sprinting.

    Science.gov (United States)

    Higashihara, Ayako; Nagano, Yasuharu; Ono, Takashi; Fukubayashi, Toru

    2018-06-01

    This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the acceleration sprint and maximum-speed sprint in 13 male sprinters during an overground sprinting. Differences in hamstring activation during each divided phases and in the hip and knee joint angles and torques at each time point of the sprinting gait cycle were determined between two sprints. During the early stance of the acceleration sprint, the hip extension torque was significantly greater than during the maximum-speed sprint, and the relative EMG activation of the BFlh muscle was significantly higher than that of the ST muscle. During the late stance and terminal mid-swing of maximum-speed sprint, the knee was more extended and a higher knee flexion moment was observed compared to the acceleration sprint, and the ST muscle showed higher activation than that of the BFlh. These results indicate that the functional demands of the medial and lateral hamstring muscles differ between two different sprint performances.

  19. Effect of platelet lysate on human cells involved in different phases of wound healing.

    Science.gov (United States)

    Barsotti, Maria Chiara; Chiara Barsotti, Maria; Losi, Paola; Briganti, Enrica; Sanguinetti, Elena; Magera, Angela; Al Kayal, Tamer; Feriani, Roberto; Di Stefano, Rossella; Soldani, Giorgio

    2013-01-01

    Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization). Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2) and inflammatory response evaluation (NFκB). Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v). Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (pplatelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points. These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing.

  20. Effect of platelet lysate on human cells involved in different phases of wound healing.

    Directory of Open Access Journals (Sweden)

    Maria Chiara Barsotti

    Full Text Available BACKGROUND: Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization. METHODOLOGY/PRINCIPAL FINDINGS: Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2 and inflammatory response evaluation (NFκB. Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v. Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (p<0.05 vs. control, comparably to the positive control. Both platelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points. CONCLUSION/SIGNIFICANCE: These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing.

  1. Sensitivity studies of different aerosol indirect effects in mixed-phase clouds

    Science.gov (United States)

    Lohmann, U.; Hoose, C.

    2009-11-01

    Aerosols affect the climate system by changing cloud characteristics. Using the global climate model ECHAM5-HAM, we investigate different aerosol effects on mixed-phase clouds: The glaciation effect, which refers to a more frequent glaciation due to anthropogenic aerosols, versus the de-activation effect, which suggests that ice nuclei become less effective because of an anthropogenic sulfate coating. The glaciation effect can partly offset the indirect aerosol effect on warm clouds and thus causes the total anthropogenic aerosol effect to be smaller. It is investigated by varying the parameterization for the Bergeron-Findeisen process and the threshold coating thickness of sulfate (SO4-crit), which is required to convert an externally mixed aerosol particle into an internally mixed particle. Differences in the net radiation at the top-of-the-atmosphere due to anthropogenic aerosols between the different sensitivity studies amount up to 0.5 W m-2. This suggests that the investigated mixed-phase processes have a major effect on the total anthropogenic aerosol effect.

  2. Sensitivity studies of different aerosol indirect effects in mixed-phase clouds

    Directory of Open Access Journals (Sweden)

    C. Hoose

    2009-11-01

    Full Text Available Aerosols affect the climate system by changing cloud characteristics. Using the global climate model ECHAM5-HAM, we investigate different aerosol effects on mixed-phase clouds: The glaciation effect, which refers to a more frequent glaciation due to anthropogenic aerosols, versus the de-activation effect, which suggests that ice nuclei become less effective because of an anthropogenic sulfate coating. The glaciation effect can partly offset the indirect aerosol effect on warm clouds and thus causes the total anthropogenic aerosol effect to be smaller. It is investigated by varying the parameterization for the Bergeron-Findeisen process and the threshold coating thickness of sulfate (SO4-crit, which is required to convert an externally mixed aerosol particle into an internally mixed particle. Differences in the net radiation at the top-of-the-atmosphere due to anthropogenic aerosols between the different sensitivity studies amount up to 0.5 W m−2. This suggests that the investigated mixed-phase processes have a major effect on the total anthropogenic aerosol effect.

  3. Analysis of expression profile of mce operon genes (mce1, mce2, mce3 operon) in different Mycobacterium tuberculosis isolates at different growth phases.

    Science.gov (United States)

    Singh, Pratibha; Katoch, V M; Mohanty, K K; Chauhan, Devendra Singh

    2016-04-01

    Mycobacterium tuberculosis (M. tuberculosis) has four homologous mammalian cell entry (mce) operons (mce1-4) that encode exported proteins and have a possible role in the virulence mechanism of this pathogen. The expression of mce operon is considered to be complex and not completely understood. Although expression of mce operon at different in vitro growth phases has been studied earlier, its expression in different M. tuberculosis isolates under different growth phases is not yet studied. The present preliminary study was conducted on a limited number of isolates to know the trend of expression pattern of mce operon genes in different M. tuberculosis isolates under different growth stages. In this study, we monitored the transcriptional profile of selected mce operon genes (mce1A, mce1D, mce2A, mce2D, mce3A, mce3C) in different M.tuberculosis isolates (MDR1, MDR2, and sensitive isolate) at early exponential and stationary phases using real-time quantitative PCR. The expression ratio of all selected mce operon genes in all M. tuberculosis isolates was reduced at the initial phase and increased substantially at a later phase of growth. Higher expression of mce1 operon genes was found in all M. tuberculosis isolates as compared to other mce operon genes (mce2 and mce3 operons) at stationary growth phase. the higher expression of mce operon genes at stationary phase (as compared to early exponential phase) suggested growth phase dependent expression of mce operon genes. This indicated that the mce operon genes might have a role in M. tuberculosis survival and adaptation on the onset of adverse condition like stationary phase. Identification of differentially expressed genes will add to our understanding of the bacilli involved in adaptation to different growth conditions.

  4. Two cases of chronic myelogenous leukemia (CML) treated with Iminitab (Glivec) in different phases

    International Nuclear Information System (INIS)

    Davoli, R.; Ciarlo, S.; Acosta, I.; Perez, S.; Lagorio, S.; Pratti, A.A.

    2003-01-01

    Full text: IMINITAB, inhibitor of cytoplasmic transduction signs, and hindering neoplastic cells growth, is a new therapeutic agent for chronic myelogenous leukemia (CML). It is a tyrosine kinase bcrabl inhibitor, inhibiting also the c-kit receptor protein in gastrointestinal neoplasia and small cells lung cancer. The aim of the present work was to evaluate the effect of this agent in CML patients in two different time-periods, namely the chronic phase and the acute one. We hereby present two patients: 1) a 48 years old patient with radioactive contamination history, and 2) a 19 years old patient. In both cases diagnosis was confirmed by BM and BM biopsy, neutrophile alkaline phosphatase, and Ph chromosome t(9;22) (q34;q11). There were non-compatible BM donors available. Both patients were treated with hydroxyurea, hydroxyurea plus interferon, and one of them adding ARAC. Since there was no favorable response an Iminitab course was started. Patient (2) with blastic crisis remitted for 12 month until subsequent relapse and death. Patient (1) treated during chronic phase is still in remission. Neither of them attained negative Ph chromosome. Up to now, current reports show a high percentage of relapse in patients treated during the acute phase, while the chronic ones present a smaller number of relapses. It is to be noted the importance of the follow up during the chronic phase, due to the short time drug utilization in our country (May 2001). Good tolerance and sustained remission in CML patients allows being optimistic regarding this therapeutic agent. (author)

  5. Pressure transient analysis in single and two-phase water by finite difference methods

    International Nuclear Information System (INIS)

    Berry, G.F.; Daley, J.G.

    1977-01-01

    An important consideration in the design of LMFBR steam generators is the possibility of leakage from a steam generator water tube. The ensuing sodium/water reaction will be largely controlled by the amount of water available at the leak site, thus analysis methods treating this event must have the capability of accurately modeling pressure transients through all states of water occurring in a steam generator, whether single or two-phase. The equation systems of the present model consist of the conservation equations together with an equation of state for one-dimensional homogeneous flow. These equations are then solved using finite difference techniques with phase considerations and non-equilibrium effects being treated through the equation of state. The basis for water property computation is Keenan's 'fundamental equation of state' which is applicable to single-phase water at pressures less than 1000 bars and temperatures less than 1300 0 C. This provides formulations allowing computation of any water property to any desired precision. Two-phase properties are constructed from values on the saturation line. The use of formulations permits the direct calculation of any thermodynamic property (or property derivative) to great precision while requiring very little computer storage, but does involve considerable computation time. For this reason an optional calculation scheme based on the method of 'transfinite interpolation' is included to give rapid computation in selected regions with decreased precision. The conservation equations were solved using the second order Lax-Wendroff scheme which includes wall friction, allows the formation of shocks and locally supersonic flow. Computational boundary conditions were found from a method-of-characteristics solution at the reservoir and receiver ends. The local characteristics were used to interpolate data from inside the pipe to the boundary

  6. Efficiency in supercritical fluid chromatography with different superficially porous and fully porous particles ODS bonded phases.

    Science.gov (United States)

    Lesellier, E

    2012-03-09

    The chromatographic efficiency, in terms of plate number per second, was dramatically improved by the introduction of sub-two microns particles with ultra-high pressure liquid chromatography (UHPLC). On the other hand, the recent development of superficially porous particles, called core-shell or fused-core particles, appears to allow the achievement of the same efficiency performances at higher speed without high pressure drops. CO₂-based mobile phases exhibiting much lower viscosities than aqueous based mobile phases allow better theoretical efficiencies, even with 3-5 μm particles, but with relative low pressure drops. They also allow much higher flow rates or much longer columns while using conventional instruments capable to operate below 400 bar. Moreover, the use of superficially porous particles in SFC could enhance the chromatographic performances even more. The kinetic behavior of ODS phases bonded on these particles was studied, with varied flow rates, outlet (and obviously inlet) pressures, temperatures, by using a homologous series (alkylbenzenes) with 10% modifier (methanol or acetonitrile) in the carbon dioxide mobile phase. Results were also compared with classical fully porous particles, having different sizes, from 2.5 to 5 μm. Superior efficiency (N) and reduced h were obtained with these new ODS-bonded particles in regards to classical ones, showing their great interest for use in SFC. However, surprising behavior were noticed, i.e. the increase of the theoretical plate number vs. the increase of the chain length of the compounds. This behavior, opposite to the one classically reported vs. the retention factor, was not depending on the outlet pressure, but on the flow rate and the temperature changes. The lower radial trans-column diffusion on this particle types could explain these results. This diffusion reduction with these ODS-bonded superficially porous particles seems to decrease with the increase of the residence time of compounds

  7. Organic and inorganic speciation of particulate matter formed during different combustion phases in an improved cookstove.

    Science.gov (United States)

    Leavey, Anna; Patel, Sameer; Martinez, Raul; Mitroo, Dhruv; Fortenberry, Claire; Walker, Michael; Williams, Brent; Biswas, Pratim

    2017-10-01

    Residential solid fuel combustion in cookstoves has established health impacts including bladder and lung cancers, cataracts, low birth weight, and pneumonia. The chemical composition of particulate matter (PM) from 4 commonly-used solid fuels (coal, dung, ambient/dry applewood, and oakwood pellets), emitted from a gasifier cookstove, as well as propane, were examined. Temporal changes between the different cookstove burn-phases were also explored. Normalized concentrations of non-refractory PM 1 , total organics, chloride, ammonium, nitrate, sulfate, and 41 particle-phase polycyclic aromatic hydrocarbons (PAHs) were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a Thermal desorption Aerosol Gas chromatograph (TAG), respectively. Coal demonstrated the highest fraction of organic matter in its particulate emission composition (98%), followed by dung (94%). Coal and dung also demonstrated the highest numbers and concentrations of PAHs. While dry applewood emitted ten times lower organic matter compared to ambient applewood, a higher fraction of these organics was composed of PAHs, especially the more toxic ones such as benzo(a)pyrene (9.63ng/L versus 0.04ng/L), and benzo(b)fluoranthene (31.32ng/L versus 0.19ng/L). Data from the AMS demonstrated no clear trends for any of the combustion fuels over the different combustion phases unlike the previously reported trends observed for the physical characteristics. Of the solid fuels, pellets demonstrated the lowest emissions. Emissions from propane were below the quantification limit of the instruments. This work highlights the benefits of incorporating additional metrics into the cookstove evaluation process, thus enriching the existing PM data inventory. Copyright © 2017. Published by Elsevier Inc.

  8. The Microstructure Evolution of Dual-Phase Pipeline Steel with Plastic Deformation at Different Strain Rates

    Science.gov (United States)

    Ji, L. K.; Xu, T.; Zhang, J. M.; Wang, H. T.; Tong, M. X.; Zhu, R. H.; Zhou, G. S.

    2017-07-01

    Tensile properties of the high-deformability dual-phase ferrite-bainite X70 pipeline steel have been investigated at room temperature under the strain rates of 2.5 × 10-5, 1.25 × 10-4, 2.5 × 10-3, and 1.25 × 10-2 s-1. The microstructures at different amount of plastic deformation were examined by using scanning and transmission electron microscopy. Generally, the ductility of typical body-centered cubic steels is reduced when its stain rate increases. However, we observed a different ductility dependence on strain rates in the dual-phase X70 pipeline steel. The uniform elongation (UEL%) and elongation to fracture (EL%) at the strain rate of 2.5 × 10-3 s-1 increase about 54 and 74%, respectively, compared to those at 2.5 × 10-5 s-1. The UEL% and EL% reach to their maximum at the strain rate of 2.5 × 10-3 s-1. This phenomenon was explained by the observed grain structures and dislocation configurations. Whether or not the ductility can be enhanced with increasing strain rates depends on the competition between the homogenization of plastic deformation among the microconstituents (ultra-fine ferrite grains, relatively coarse ferrite grains as well as bainite) and the progress of cracks formed as a consequence of localized inconsistent plastic deformation.

  9. Ionospheric perturbations in possible association with the 2010 Haiti earthquake, as based on medium-distance subionospheric VLF propagation data

    Directory of Open Access Journals (Sweden)

    M. Hayakawa

    2011-02-01

    Full Text Available Ionospheric perturbations in possible association with the 2010 Haiti earthquake occurred on 12 January 2010 (with a magnitude of 7.0 and depth of 10 km are investigated on the basis of subionospheric propagation data from the NAA transmitter on the east coast of the USA to a VLF receiving station in Peru. The local nighttime VLF amplitude data are extensively investigated during the period from the beginning of October 2009 to the end of March 2010, in which the trend (nighttime average amplitude, dispersion and nighttime fluctuation are analysed. It is found that a clear precursory ionosphere perturbation is detected just around New Years day of 2010, about 12 days before the main shock, which is characterised by the simultaneous decrease in the trend and the increases in dispersion and nighttime fluctuation. An additional finding might be the presence of the effect of the Earth's tide one and two months before the main shock, which can only be seen for a huge EQ.

  10. Spectral broadening of VLF transmitter signals and sideband structure observed on Aureol 3 satellite at middle latitudes

    International Nuclear Information System (INIS)

    Tanaka, Y.; Hayakawa, M.; Lagoutte, D.; Lefeuvre, F.; Tajima, S.

    1987-01-01

    Electric and magnetic field wave data acquired on Aureol 3 satellite demonstrate the existence of a spectral broadening effect in which VLF transmitter signals from Alpha station (geographic coordinates, 50.5 degree N, 137 degree E) in USSR undergo a significant spectral broadening on electric fields as they propagate through the ionosphere up to the spacecraft in the altitude range of 500-2,000 km at middle latitudes (L ∼ 2). The spectral broadening phenomena may be divided into two types: (1) spectrally broadened components occurring without any association with ELF/VLF emissions under disturbed ionospheric conditions and (2) spectrally broadened components with predominant sideband structure in association with ELF emissions. Bicoherence computation results suggest a nonlinear mode coupling between the transmitter signal and ELF emission which produces sidebands that are quasi-electrostatic in nature. However, faint spectral broadened components in both types 1 and 2 may be connected with Doppler shift of quasi-electrostatic whistler mode waves with a broad spectrum of k near the resonance cone, due to scattering of the transmitter signals from ionospheric irregularities in the F region

  11. Phase-dependent quantum interference between different pathways in bichromatic harmonic generation

    International Nuclear Information System (INIS)

    Jun, Cai; Li-Ming, Wang; Hao-Xue, Qiao

    2009-01-01

    This paper studies the harmonic generation of the hydrogen atom subjected to a collinear bichromatic laser field by numerically solving the time-dependent Schrödinger equation using the split-operator pseudo-spectral method. By adding a frequency variation to the additional field, the contributions of different pathways to particular order harmonic generation can be isolated. The quantum interference pattern between harmonic pathways, which influences the harmonic intensity, is found to be either constructive or destructive with respect to different relative phase of the two field components. Detailed description of up to the 35th-order harmonics and the harmonic pathways for a wide range of field parameters is presented. (atomic and molecular physics)

  12. Modelling phase separation in Fe-Cr system using different atomistic kinetic Monte Carlo techniques

    International Nuclear Information System (INIS)

    Castin, N.; Bonny, G.; Terentyev, D.; Lavrentiev, M.Yu.; Nguyen-Manh, D.

    2011-01-01

    Atomistic kinetic Monte Carlo (AKMC) simulations were performed to study α-α' phase separation in Fe-Cr alloys. Two different energy models and two approaches to estimate the local vacancy migration barriers were used. The energy models considered are a two-band model Fe-Cr potential and a cluster expansion, both fitted to ab initio data. The classical Kang-Weinberg decomposition, based on the total energy change of the system, and an Artificial Neural Network (ANN), employed as a regression tool were used to predict the local vacancy migration barriers 'on the fly'. The results are compared with experimental thermal annealing data and differences between the applied AKMC approaches are discussed. The ability of the ANN regression method to accurately predict migration barriers not present in the training list is also addressed by performing cross-check calculations using the nudged elastic band method.

  13. Harmonics Suppression for Single-Phase Grid-Connected Photovoltaic Systems in Different Operation Modes

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2013-01-01

    -connected PV inverters may be severely affected in different operation modes. In this paper, a detailed analysis is conducted to reveal the relationship between the harmonics level with the power factor and the current level in the PV systems. A current control solution which employs an Internal Model...... Principle (IMP) is proposed to suppress the harmonic currents injected into the grid. Experiments are carried out to verify the analysis and the performance of the proposed control method. It is demonstrated that the proposed method presents an effective solution to harmonics suppression for single......-phase grid-connected PV systems in different operation modes. Especially, it can remove higher order harmonics effectively leading to a better power quality compared to the Proportional plus Multi-Resonant Controller, and it has less computational burden....

  14. Effect of phase change material on the heat transfer rate of different building materials

    Science.gov (United States)

    Hasan, Mushfiq; Alam, Shahnur; Ahmed, Dewan Hasan

    2017-12-01

    Phase change material (PCM) is widely known as latent heat storage. A comprehensive study is carried out to investigate the effect of PCM on heat transfer rate of building materials. Paraffin is used as PCM along with different conventional building materials to investigate the heat transfer rate from the heated region to the cold region. PCM is placed along with the three different types of building materials like plaster which is well know building material in urban areas and wood and straw which are commonly used in rural areas for roofing as well as wall panel material and investigated the heat transfer rate. An experimental setup was constructed with number of rectangular shape aluminum detachable casing (as cavity) and placed side by side. Series of rectangular cavity filled with convent ional building materials and PCM and these were placed in between two chambers filled with water at different temperature. Building materials and PCM were placed in different cavities with different combinations and investigated the heat transfer rate. The results show that using the PCM along with other building materials can be used to maintain lower temperature at the inner wall and chamber of the cold region. Moreover, the placement or orientation of the building materials and PCM make significant contribution to heat transfer rate from the heated zone to the cold zone.

  15. MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems

    Energy Technology Data Exchange (ETDEWEB)

    Avanesov, Maxim, E-mail: m.avanesov@uke.de [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Weinrich, Julius M.; Kraus, Thomas [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Derlin, Thorsten [Department of Nuclear Medicine, Hannover Medical School (Germany); Adam, Gerhard; Yamamura, Jin [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Karul, Murat [Department of Diagnostic and Interventional Radiology, Marienkrankenhaus Hamburg (Germany)

    2016-11-15

    Objectives: The purpose of the retrospective study was to evaluate the additional value of dual-phase multidetector computed tomography (MDCT) protocols over a single-phase protocol on initial MDCT in patients with acute pancreatitis using three CT-based pancreatitis severity scores with regard to radiation dose. Methods: In this retrospective, IRB approved study MDCT was performed in 102 consecutive patients (73 males; 55years, IQR48–64) with acute pancreatitis. Inclusion criteria were CT findings of interstitial edematous pancreatitis (IP) or necrotizing pancreatitis (NP) and a contrast-enhanced dual-phase (arterial phase and portal-venous phase) abdominal CT performed at ≥72 h after onset of symptoms. The severity of pancreatic and extrapancreatic changes was independently assessed by 2 observers using 3 validated CT-based scoring systems (CTSI, mCTSI, EPIC). All scores were applied to arterial phase and portal venous phase scans and compared to score results of portal venous phase scans, assessed ≥14 days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations. Results: In neither of the CT severity scores a significant difference was observed after application of a dual-phase protocol compared with a single-phase protocol (IP: CTSI: 2.7 vs. 2.5, p = 0.25; mCTSI: 4.0 vs. 4.0, p = 0.10; EPIC: 2.0 vs. 2.0, p = 0.41; NP: CTSI: 8.0 vs. 7.0, p = 0.64; mCTSI: 8.0 vs. 8.0, p = 0.10; EPIC: 3.0 vs. 3.0, p = 0.06). The application of a single-phase CT protocol was associated with a median effective dose reduction of 36% (mean dose reduction 31%) compared to a dual-phase CT scan. Conclusions: An initial dual-phase abdominal CT after ≥72 h after onset of symptoms of acute pancreatitis was not superior to a single-phase protocol for evaluation of the severity of pancreatic and extrapancreatic changes. However, the effective radiation dose may be reduced by 36% using a

  16. Antibacterial photocatalytic activity of different crystalline TiO2 phases in oral multispecies biofilm.

    Science.gov (United States)

    Pantaroto, Heloisa N; Ricomini-Filho, Antonio P; Bertolini, Martinna M; Dias da Silva, José Humberto; Azevedo Neto, Nilton F; Sukotjo, Cortino; Rangel, Elidiane C; Barão, Valentim A R

    2018-07-01

    Titanium dioxide (TiO 2 ) incorporation in biomaterials is a promising technology due to its photocatalytic and antibacterial activities. However, the antibacterial potential of different TiO 2 crystalline structures on a multispecies oral biofilm remains unknown. We hypothesized that the different crystalline TiO 2 phases present different photocatalytic and antibacterial activities. Three crystalline TiO 2 films were deposited by magnetron sputtering on commercially pure titanium (cpTi), in order to obtain four groups: (1) machined cpTi (control); (2) A-TiO 2 (anatase); (3) M-TiO 2 (mixture of anatase and rutile); (4) R-TiO 2 (rutile). The morphology, crystalline phase, chemical composition, hardness, elastic modulus and surface free energy of the surfaces were evaluated. The photocatalytic potential was assessed by methylene blue degradation assay. The antibacterial activity was evaluated on relevant oral bacteria, by using a multispecies biofilm (Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum) formed on the treated titanium surfaces (16.5h) followed by UV-A light exposure (1h) to generate reactive oxygen species production. All TiO 2 films presented around 300nm thickness and improved the hardness and elastic modulus of cpTi surfaces (p0.05 vs. control). This study brings new insights on the development of extra oral protocols for the photocatalytic activity of TiO 2 in oral biofilm-associated disease. Anatase and mixture-TiO 2 showed antibacterial activity on this oral bacterial biofilm, being promising surface coatings for dental implant components. Copyright © 2018 The Academy of Dental Materials. All rights reserved.

  17. Aging in autonomic control by multifractal studies of cardiac interbeat intervals in the VLF band

    International Nuclear Information System (INIS)

    Makowiec, Danuta; Kryszewski, Stanisław; Rynkiewicz, Andrzej; Wdowczyk-Szulc, Joanna; Żarczyńska-Buchowiecka, Marta; Gałąska, Rafał

    2011-01-01

    The heart rate responds dynamically to various intrinsic and environmental stimuli. The autonomic nervous system is said to play a major role in this response. Multifractal analysis offers a novel method to assess the response of cardiac interbeat intervals. Twenty-four hour ECG recordings of RR interbeat intervals (of 48 elderly volunteers (age 65–94), 40 middle-aged persons (age 45–53) and 36 young adults (age 18–26)) were investigated to study the effect of aging on autonomic regulation during normal activity in healthy adults. Heart RR-interval variability in the very low frequency (VLF) band (32–420 RR intervals) was evaluated by multifractal tools. The nocturnal and diurnal signals of 6 h duration were studied separately. For each signal, the analysis was performed twice: for a given signal and for the integrated signal. A multifractal spectrum was quantified by the h max value at which a multifractal spectrum attained its maximum, width of a spectrum, Hurst exponent, extreme events h left and distance between the maxima of a signal and its integrated counterpart. The following seven characteristics are suggested as quantifying the age-related decrease in the autonomic function ('int' refers to the integrated signal): (a) h sleep max − h max wake > 0.05 for a signal; (b) h int max > 1.15 for wake; (c) h int max − h max > 0.85 for sleep; (d) Hurst wake − Hurst sleep < 0.01; (e) width wake > 0.07; (f) width int < 0.30 for sleep; (g) h int left > 0.75. Eighty-one percent of elderly people had at least four of these properties, and ninety-two percent of young people had three or less. This shows that the multifractal approach offers a concise and reliable index of healthy aging for each individual. Additionally, the applied method yielded insights into dynamical changes in the autonomic regulation due to the circadian cycle and aging. Our observations support the hypothesis that imbalance in the autonomic control due to healthy aging could

  18. The relationship between gut hormone secretion and gastric emptying in different phases of the migrating motor complex

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, L.; Oester-Joergensen, E.; Quist, N. [Odense University Hospital, Odense (Denmark); and others

    1996-05-01

    No studies are available on the relationship between the response of gut hormones and gastric emptying in different phases of the migrating motor complex. This study examined whether basal gut hormone concentrations in plasma before food ingestion are predictors of emptying characteristics and whether different hormone secretion patterns are associated with specific alteration in emptying rate. 12 healthy men were examined on two occasion: one with meal ingestion in phase I and the other with meal ingestion in phase II. The meal consisted of an omelette labelled with {sup 99m}Tc followed by 150 ml water labelled with {sup 111}In. Plasma concentrations of gastrin, cholecystokinin, motilin, and peptide YY were measured in the fasting state, immediately after food ingestion, and at 15 min-min intervals in the postprandial period. New findings from the present study include a higher incremental integrated postprandial motilin response in phase I than in phase II, and a linear relationship between median total integrated motilin response and solid emptying at 120 min in phase I. Furthermore, in phase I a linear relationship between total integrated area of cholecystokinin and solid emptying at 120 min was demonstrated. The findings from the present investigation have to be considered in the future design of studies that focus on postprandial release of gastrointestinal hormones. The transition from phase III to phase I is a reproducible and easily recognized pressure event. Therefore, the authors recommend the use of food ingestion immediately after termination of duodenal phase III. 14 refs.

  19. Geotechnical properties of municipal solid waste at different phases of biodegradation

    International Nuclear Information System (INIS)

    Reddy, Krishna R.; Hettiarachchi, Hiroshan; Gangathulasi, Janardhanan; Bogner, Jean E.

    2011-01-01

    Highlights: → Degraded synthetic municipal solid waste (MSW) anaerobically in controlled bench-scale reactors. → Performed laboratory tests to determine geotechnical properties of MSW at different phases of degradation. → Hydraulic conductivity decreased by two orders of magnitude due to degradation. → Compression ratio reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. → Friction angle reduced, but cohesion increased with degradation. - Abstract: This paper presents the results of laboratory investigation conducted to determine the variation of geotechnical properties of synthetic municipal solid waste (MSW) at different phases of degradation. Synthetic MSW samples were prepared based on the composition of MSW generated in the United States and were degraded in bioreactors with leachate recirculation. Degradation of the synthetic MSW was quantified based on the gas composition and organic content, and the samples exhumed from the bioreactor cells at different phases of degradation were tested for the geotechnical properties. Hydraulic conductivity, compressibility and shear strength of initial and degraded synthetic MSW were all determined at constant initial moisture content of 50% on wet weight basis. Hydraulic conductivity of synthetic MSW was reduced by two orders of magnitude due to degradation. Compression ratio was reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. Direct shear tests showed that the fresh and degraded synthetic MSW exhibited continuous strength gain with increase in horizontal deformation, with the cohesion increased from 1 kPa for fresh MSW to 16-40 kPa for degraded MSW and the friction angle decreased from 35 o for fresh MSW to 28 o for degraded MSW. During the triaxial tests under CU condition, the total strength parameters, cohesion and friction angle, were found to vary from 21 to 57 kPa and 1 o to 9 o , respectively, while the effective strength parameters, cohesion

  20. Observation of different phases during an ELM crash with the help of nitrogen seeding

    International Nuclear Information System (INIS)

    Schneider, P A; Wolfrum, E; Dunne, M G.; Dux, R; Gude, A; Kurzan, B; Pütterich, T; Rathgeber, S K.; Weller, A; Wenninger, R; Vicente, J

    2014-01-01

    A new method was applied to indirectly obtain information about the features of the crash of the H-mode edge transport barrier in consequence of an edge localized mode (ELM). The method is based on a combination of fast measurements, without spatial resolution, and relatively slow measurements, with high spatial resolution. The comparison of two different ELM scenarios in the full metal tokamak ASDEX Upgrade—a standard scenario and one with additional nitrogen seeding—revealed a two-fold nature of the ELM crash. In the case with additional nitrogen only a part of the standard crash is observed. This suggests the standard ELM crash consists of two or more consecutive events instead of a single distinct one. Some of these events are observed to be suppressed with changes in plasma parameters. The effect of the impurity seeding on different plasma parameters is documented in detail and compared to measurements conducted in machines with a carbon wall. The radial extent of the phases observed during the ELM crash differs in the kinetic profiles, with one instability extending inside the pedestal top and the other being confined to the pedestal region. This picture can explain the differences in the loss of stored energy and the change in ELM frequency which are observed for the analysed pair of discharges. It also suggests that the ELM crash starts at the pedestal top and only then affects the steep gradient region. (paper)

  1. Late-phase MSCT in the different stages of myocardial infarction: animal experiments

    International Nuclear Information System (INIS)

    Mahnken, Andreas H.; Bruners, Philipp; Kinzel, Sylvia; Katoh, Marcus; Muehlenbruch, Georg; Guenther, Rolf W.; Wildberger, Joachim E.

    2007-01-01

    The purpose of this study was to intraindividually evaluate myocardial late enhancement on multislice spiral computed tomography (MSCT) for the assessment of the different stages of myocardial infarction (MI) in comparison with magnetic resonance (MR) imaging. Reperfused MI was successfully induced in seven pigs. Delayed enhancement MR imaging and late-phase MSCT were performed on day 0 as well as 7, 28 and 90 days after the procedure. The pigs were sacrificed, and 2,3,5-triphenyltetrazolin-chloride (TTC) staining was acquired. MI size was compared between the different imaging techniques and over time applying Bland-Altman plots and multivariate analysis with repeated measures. On day 0 the mean MI size was 23.7 ± 11.8% of the left ventricular area on MSCT and 24.5 ± 10.6% on MR imaging. On day 90 infarct sizes decreased significantly to 16.9 ± 8.4% and 18.9 ± 8.0%, respectively (P 0.0019). On TTC staining the size of MI was 16.8 ± 8.2%. Bland-Altman plots showed a good agreement between MSCT and MR imaging with mean deviations ranging from -3.4% to -1.9%. No significant difference between MSCT and MR imaging was found. Myocardial late enhancement on MSCT correlates well with delayed enhancement MR imaging during the different stages of MI and allows for reliable assessment of reperfused MI during acute, subacute and chronic stages. (orig.)

  2. Differences in Funding Sources of Phase III Oncology Clinical Trials by Treatment Modality and Cancer Type.

    Science.gov (United States)

    Jairam, Vikram; Yu, James B; Aneja, Sanjay; Wilson, Lynn D; Lloyd, Shane

    2017-06-01

    Given the limited resources available to conduct clinical trials, it is important to understand how trial sponsorship differs among different therapeutic modalities and cancer types and to consider the ramifications of these differences. We searched clinicaltrials.gov for a cross-sectional register of active, phase III, randomized controlled trials (RCTs) studying treatment-related endpoints such as survival and recurrence for the 24 most prevalent malignancies. We classified the RCTs into 7 categories of therapeutic modality: (1) chemotherapy/other cancer-directed drugs, (2) targeted therapy, (3) surgery, (4) radiation therapy (RT), (5) RT with other modalities, (6) multimodality therapy without RT, and (7) other. RCTs were categorized as being funded by one or more of the following groups: (1) government, (2) hospital/university, (3) industry, and (4) other. χ analysis was performed to detect differences in funding source distribution between modalities and cancer types. The percentage of multimodality trials (5%) and radiation RCTs (4%) funded by industry was less than that for chemotherapy (32%, Pfunding than any of the other modalities (Pfunded by industry if they also studied targeted therapy (Pfunded by industry than trials studying multimodality therapy or radiation. The impact of industry funding versus institutional or governmental sources of funding for cancer research is unclear and requires further study.

  3. Synthesis of a mixed-model stationary phase derived from glutamine for HPLC separation of structurally different biologically active compounds: HILIC and reversed-phase applications.

    Science.gov (United States)

    Aral, Tarık; Aral, Hayriye; Ziyadanoğulları, Berrin; Ziyadanoğulları, Recep

    2015-01-01

    A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel (4 µm, 60 Å). The prepared stationary phase was characterized by IR and elemental analysis. The new stationary phase bears an embedded amide group into phenyl ring, highly polar a terminal amide group and non-polar groups (phenyl and alkyl groups). At first, this new mixed-mode stationary phase was used for HILIC separation of four nucleotides and five nucleosides. The effects of different separation conditions, such as pH value, mobile phase and temperature, on the separation process were investigated. The optimum separation for nucleotides was achieved using HILIC isocratic elution with aqueous mobile phase and acetonitrile with 20°C column temperature. Under these conditions, the four nucleotides could be separated and detected at 265 nm within 14 min. Five nucleosides were separated under HILIC isocratic elution with aqueous mobile phase containing pH=3.25 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 265 nm within 14 min. Chromatographic parameters as retention factor, selectivity, theoretical plate number and peak asymmetry factor were calculated for the effect of temperature and water content in mobile phase on the separation process. The new column was also tested for nucleotides and nucleosides mixture and six analytes were separated in 10min. The chromatographic behaviours of these polar analytes on the new mixed-model stationary phase were compared with those of HILIC columns under similar conditions. Further, phytohormones and phenolic compounds were separated in order to see influence of the new stationary phase in reverse phase conditions. Eleven plant phytohormones were separated within 13 min using RP-HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 230 or 278 nm. The best separation

  4. Bifurcation and phase diagram of turbulence constituted from three different scale-length modes

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, S.-I.; Kitazawa, A.; Yagi, M. [Kyushu Univ., Research Inst. for Applied Mechanics, Kasuga, Fukuoka (Japan); Itoh, K. [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2002-04-01

    Cases where three kinds of fluctuations having the different typical scale-lengths coexist are analyzed, and the statistical theory of strong turbulence in inhomogeneous plasmas is developed. Statistical nonlinear interactions between fluctuations are kept in the analysis as the renormalized drag, statistical noise and the averaged drive. The nonlinear interplay through them induces a quenching or suppressing effect, even if all the modes are unstable when they are analyzed independently. Variety in mode appearance takes place: one mode quenches the other two modes, or one mode is quenched by the other two modes, etc. The bifurcation of turbulence is analyzed and a phase diagram is drawn. Phase diagrams with cusp type catastrophe and butterfly type catastrophe are obtained. The subcritical bifurcation is possible to occur through the nonlinear interplay, even though each one is supercritical turbulence when analyzed independently. Analysis reveals that the nonlinear stability boundary (marginal point) and the amplitude of each mode may substantially shift from the conventional results of independent analyses. (author)

  5. High pressure study of the zinc phosphide semiconductor compound in two different phases

    International Nuclear Information System (INIS)

    Mokhtari, Ali

    2009-01-01

    Electronic and structural properties of the zinc phosphide semiconductor compound are calculated at hydrostatic pressure using the full-potential all-electron linearized augmented plane wave plus local orbital (FP-LAPW+lo) method in both cubic and tetragonal phases. The exchange-correlation potential is treated by the generalized gradient approximation within the scheme of Perdew, Burke and Ernzerhof, GGA96 (1996 Phys. Rev. Lett. 77 3865). Also, the Engel and Vosko GGA formalism, EV-GGA (Engel and Vosko 1993 Phys. Rev. B 47 13164), is used to improve the band-gap results. Internal parameters are optimized by relaxing the atomic positions in the force directions using the Hellman-Feynman approach. The lattice constants, internal parameters, bulk modulus, cohesive energy and band structures have been calculated and compared to the available experimental and theoretical results. The structural calculations predict that the stable phase is tetragonal. The effects of hydrostatic pressure on the behavior of band parameters such as band-gap, valence bandwidths and internal gaps (the energy gap between different parts of the valence bands) are studied using both GGA96 and EV-GGA.

  6. High pressure study of the zinc phosphide semiconductor compound in two different phases

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, Ali [Simulation Laboratory, Department of Physics, Faculty of Science, Shahrekord University, PB 115, Shahrekord (Iran, Islamic Republic of)], E-mail: mokhtari@sci.sku.ac.ir

    2009-07-08

    Electronic and structural properties of the zinc phosphide semiconductor compound are calculated at hydrostatic pressure using the full-potential all-electron linearized augmented plane wave plus local orbital (FP-LAPW+lo) method in both cubic and tetragonal phases. The exchange-correlation potential is treated by the generalized gradient approximation within the scheme of Perdew, Burke and Ernzerhof, GGA96 (1996 Phys. Rev. Lett. 77 3865). Also, the Engel and Vosko GGA formalism, EV-GGA (Engel and Vosko 1993 Phys. Rev. B 47 13164), is used to improve the band-gap results. Internal parameters are optimized by relaxing the atomic positions in the force directions using the Hellman-Feynman approach. The lattice constants, internal parameters, bulk modulus, cohesive energy and band structures have been calculated and compared to the available experimental and theoretical results. The structural calculations predict that the stable phase is tetragonal. The effects of hydrostatic pressure on the behavior of band parameters such as band-gap, valence bandwidths and internal gaps (the energy gap between different parts of the valence bands) are studied using both GGA96 and EV-GGA.

  7. Motor activity changes induced by sub-encephalopathic lead exposure during different developmental phases in rats

    International Nuclear Information System (INIS)

    Van Rooyen, J.M.; Offermeier, J.; Brand, L.; Botha, F.; Rossouw, J.; Lategan, A.J.; Botes, M.S.

    1988-01-01

    Two groups of rats were exposed to lead (0,2% lead acetate in drinking water) for periods of 21 days during different developmental phases. Lead exposure was initiated on day 1 and day 22 after birth, for rats in groups 1 and 2, respectively. Measurements of locomotor activity (LA) and [ 3 H]spiperone binding assays were performed on day 50 after birth. Lead exposure resulted in the potentiation of the LA effects of 5 mg/kg apomorphine without altering the LA effects of 50 mg/kg piribedil in group 1. Lead exposure resulted in an attenuation of the LA effects of apomorphine and piribedil in group 2. Lead exposure did not alter the K D and B max values of [ 3 H]spiperone in membranes prepared from the rat striatum or nucleus accumbens

  8. Synthesis of polymer membranes of different porosity and their application for phenol removal from liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Hofman-Bieniek, Magdalena; Jasiewicz, Katarzyna; Pietrzak, Robert [Adam Mickiewicz University in Poznan, Poznan (Poland)

    2014-02-15

    Preparation of polymeric membranes based on polyethersulfone (PES) modified by adding different amounts of a pore-forming agent (PVP) is presented, and potential application of the membranes obtained for removal of phenol from the liquid phase is examined. The addition of various amounts of PVP has been shown to bring about changes in the content of the surface oxygen groups, but has no significant effect on the chemical character of the groups and acidic groups dominate. Filtration by phenol solution leads to significant changes in the total content of surface oxides; however, the acidic groups remain dominant. Membranes characterized by higher porosity exhibited more stable and higher rejection ratio for phenol removal. Although all the membranes were characterized by similar rejection ratios for phenol removal, the cake resistance (Rc) and pore resistance (Rp) values were found to depend significantly on the structure and porosity of the membrane applied for filtration.

  9. Synthesis of polymer membranes of different porosity and their application for phenol removal from liquid phase

    International Nuclear Information System (INIS)

    Hofman-Bieniek, Magdalena; Jasiewicz, Katarzyna; Pietrzak, Robert

    2014-01-01

    Preparation of polymeric membranes based on polyethersulfone (PES) modified by adding different amounts of a pore-forming agent (PVP) is presented, and potential application of the membranes obtained for removal of phenol from the liquid phase is examined. The addition of various amounts of PVP has been shown to bring about changes in the content of the surface oxygen groups, but has no significant effect on the chemical character of the groups and acidic groups dominate. Filtration by phenol solution leads to significant changes in the total content of surface oxides; however, the acidic groups remain dominant. Membranes characterized by higher porosity exhibited more stable and higher rejection ratio for phenol removal. Although all the membranes were characterized by similar rejection ratios for phenol removal, the cake resistance (Rc) and pore resistance (Rp) values were found to depend significantly on the structure and porosity of the membrane applied for filtration

  10. Use of geostatistics on broiler production for evaluation of different minimum ventilation systems during brooding phase

    Directory of Open Access Journals (Sweden)

    Thayla Morandi Ridolfi de Carvalho

    2012-01-01

    Full Text Available The objective of this research was to evaluate different minimum ventilation systems, in relation to air quality and thermal comfort using geostatistics in brooding phase. The minimum ventilation systems were: Blue House I: exhaust fans + curtain management (end of the building; Blue House II: exhaust fans + side curtain management; and Dark House: exhaust fans + flag. The climate variables evaluated were: dry bulb temperature, relative humidity, air velocity, carbon dioxide and ammonia concentration, during winter time, at 9 a.m., in 80 equidistant points in brooding area. Data were evaluated by geostatistic technique. The results indicate that Wider broiler houses (above 15.0 m width present the greatest ammonia and humidity concentration. Blue House II present the best results in relation to air quality. However, none of the studied broiler houses present an ideal thermal comfort.

  11. Control of magnetic vortex polarity by the phase difference between voltage signals

    Science.gov (United States)

    Cui, Huanqing; Cai, Li; Yang, Xiaokuo; Wang, Sen; Zhang, Mingliang; Li, Cheng; Feng, Chaowen

    2018-02-01

    Using micromagnetic simulations, we investigate the voltage control of magnetic vortex polarity based on a designed multiferroic heterostructure that contains two separate piezoelectric films beneath a magnetostrictive nanodisk. The results show that controllable switching of vortex polarity can be achieved by proper modulation of the phase difference between two sinusoidal voltage pulses V1 and V2, which are applied to the two separate piezoelectric films, respectively. The frequencies of V1 and V2 are set at the gyrotropic eigenfrequency fG of the nanodisk, and the vortex polarity switching is completed via the nucleation-annihilation process of the vortex-antivortex pair. Our findings provide an additional effective means for ultralow power switching of the magnetic vortex, which lays the foundation for voltage-controlled vortex random access memory.

  12. Motor activity changes induced by sub-encephalopathic lead exposure during different developmental phases in rats

    Energy Technology Data Exchange (ETDEWEB)

    Van Rooyen, J M; Offermeier, J; Brand, L; Botha, F; Rossouw, J; Lategan, A J; Botes, M S

    1988-05-01

    Two groups of rats were exposed to lead (0,2% lead acetate in drinking water) for periods of 21 days during different developmental phases. Lead exposure was initiated on day 1 and day 22 after birth, for rats in groups 1 and 2, respectively. Measurements of locomotor activity (LA) and (/sup 3/H)spiperone binding assays were performed on day 50 after birth. Lead exposure resulted in the potentiation of the LA effects of 5 mg/kg apomorphine without altering the LA effects of 50 mg/kg piribedil in group 1. Lead exposure resulted in an attenuation of the LA effects of apomorphine and piribedil in group 2. Lead exposure did not alter the K/sub D/ and B/sub max/ values of (/sup 3/H)spiperone in membranes prepared from the rat striatum or nucleus accumbens.

  13. Influence of salinity stress on the height and productivity features of durum wheat samples in different phases of vegetation

    Directory of Open Access Journals (Sweden)

    A. Z. Sikhmuradov

    2010-01-01

    Full Text Available Influence of salinity stress on the morphological features of durum wheat in different phases of vegetation is studied in the work. It is revealed that in earlier phases the samples have weak stability, but further salt-stability increases.

  14. Using Real-Worldness and Cultural Difference to Enhance Student Learning in a Foundation Phase Life Skills Module

    Science.gov (United States)

    Koen, Mariette; Ebrahim, Hasina Banu

    2013-01-01

    Our aim was to explore how real-world experience, inclusive of engagement with cultural differences, influences the quality of students' learning in a Life Skills module in pre-service Foundation Phase teacher education. The study was conducted with 147 students in their final year of the Bachelor of Education (Foundation Phase specialisation), at…

  15. Interaction of fibrinogen and albumin with titanium dioxide nanoparticles of different crystalline phases

    International Nuclear Information System (INIS)

    Marucco, Arianna; Fenoglio, Ivana; Turci, Francesco; Fubini, Bice

    2013-01-01

    TiO 2 nanoparticles (NPs) are contained in different kinds of industrial products including paints, self-cleaning glasses, sunscreens. TiO 2 is also employed in photocatalysis and it has been proposed for waste water treatment. Micrometric TiO 2 is generally considered a safe material, while there is concern on the possible health effects of nanometric titania. Due to their small size NPs may migrate within the human body possibly entering in the blood stream. Therefore studies on the interaction of NPs with plasma proteins are needed. In fact, the interaction with proteins is believed to ultimately influences the NPs biological fate. Fibrinogen and albumin are two of the most abundant plasma proteins. They are involved in several important physiological functions. Furthermore, fibrinogen is known to trigger platelet adhesion and inflammation. For these reasons the study of the interaction between these protein and nanoparticles is an important step toward the understanding of the behavior of NPs in the body. In this study we investigated the interaction of albumin and fibrinogen with TiO 2 nanoparticles of different crystal phases (rutile and anatase) using an integrated set of techniques. The amount of adsorbed fibrinogen and albumin for each TiO 2 surface was investigated by using the bicinchoninic acid assay (BCA). The variation of the surface charge of the NP-protein conjugates respect to the naked NPs was used to indirectly estimate both surface coverage and reversibility of the adsorption upon dilution. Surface charge was monitored by measuring the ζ potential with a conventional electrophoretic light scattering (ELS) system. The extent of protein deformation was evaluated by Raman Spectroscopy. We found that both proteins adsorb irreversibly against electrostatic repulsion, likely undergoing conformational changes or selective orientation upon adsorption. The size of primary particles and the particles aggregation rather than the crystal phase modulate the

  16. Phase change Materials (PCM) microcapsules with different shell compositions: Preparation, characterization and thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Bayes-Garcia, L.; Ventola, L.; Cordobilla, R.; Benages, R.; Calvet, T.; Cuevas-Diarte, M.A. [Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques s/n, E-08028 Barcelona (Spain)

    2010-07-15

    In this study, phase change materials (Rubitherm registered RT 27) microcapsules were successfully obtained by two different methods. The main difference between them remains on the shell composition, as they are composed of different coacervates (Sterilized Gelatine/Arabic Gum for the SG/AG method and Agar-Agar/Arabic Gum for the AA/AG method). Microcapsules were thermally characterized by thermo-optical microscopy and differential scanning calorimetry. Using scanning electron microscopy, their spherical morphology (sphericity factor of 0.94-0.95) and their particle size distribution were determined, obtaining an average diameter of 12 {mu}m for the SG/AG method and lower values for the AA/AG method, where nanocapsules were also observed (average diameter of 4.3 {mu}m for the microcapsules and 104 nm for the nanocapsules). The thermal stability determination was carried out by Thermogravimetric analyses (TG) and the results show a high decomposition temperature, although the process takes places in four steps for the two mentioned methods. Moreover, the microcapsules obtained by the AA/AG method decompose in a more gradual way, as in the TG results a double step, instead of one, is appreciable. On the whole, the prepared microencapsulated PCM are totally capable of developing their role in thermal energy storage. (author)

  17. Partitioning of metals in different binding phases of tropical estuarine sediments: importance of metal chemistry

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Chakraborty, S.; Vudamala, K.; Sarkar, Arindam; Nath, B.N.

    association with Fe/Mn oxide phases followed by Ni and Cu. Faster k-w of Cu (II) (1×109 s-1) increased the rate of complex formation of Cu2+ ion with ligand in the organic phases. The Cu–ligand (from organic phase...

  18. The relationship between gut hormone secretion and gastric emptying in different phases of the migrating motor complex

    DEFF Research Database (Denmark)

    Rasmussen, L; Oster-Jørgensen, E; Qvist, N

    1996-01-01

    a higher incremental integrated postprandial motilin response in phase I than in phase II (998 pmol/l*30 min (495 to 2010) versus 210 pmol/l*30 min (-270 to 2323), p total integrated motilin response and solid emptying at 120 min in phase I (Rs = 0.58; p......BACKGROUND: No studies are available on the relationship between the response of gut hormones and gastric emptying in different phases of the migrating motor complex. This study examined whether basal gut hormone concentrations in plasma before food ingestion are predictors of emptying...... total integrated area of cholecystokinin and solid emptying at 120 min was demonstrated (Rs = 0.62; p

  19. The relationship between gut hormone secretion and gastric emptying in different phases of the migrating motor complex

    DEFF Research Database (Denmark)

    Rasmussen, L; Oster-Jørgensen, E; Qvist, N

    1996-01-01

    BACKGROUND: No studies are available on the relationship between the response of gut hormones and gastric emptying in different phases of the migrating motor complex. This study examined whether basal gut hormone concentrations in plasma before food ingestion are predictors of emptying characteri......BACKGROUND: No studies are available on the relationship between the response of gut hormones and gastric emptying in different phases of the migrating motor complex. This study examined whether basal gut hormone concentrations in plasma before food ingestion are predictors of emptying...... a higher incremental integrated postprandial motilin response in phase I than in phase II (998 pmol/l*30 min (495 to 2010) versus 210 pmol/l*30 min (-270 to 2323), p linear relationship between median total integrated motilin response and solid emptying at 120 min in phase I (Rs = 0.58; p...... linear relationship between total integrated area of cholecystokinin and solid emptying at 120 min was demonstrated (Rs = 0.62; p

  20. Different Phases of Earthquake Cycle Reflected in GPS Measured Crustal Deformations along the Andes

    Science.gov (United States)

    Khazaradze, G.; Klotz, J.

    2001-12-01

    largest ever recorded earthquake on the earth. To properly interpret given observations, we developed the fully \\textsc{3D} Andean Elastic Dislocation Model (AEDM), which is used to explain the dominant inter-seismic signal. The subtraction of the AEDM predicted deformation rates from the observations leads towards the "filtered" residual velocity field, that can be used to highlight, for example, the post-seismic deformation effects. Also, in the central section of the SAGA network, the residual velocity field indicates the existence of more long-term (i.e. geologic) deformations. In summary, the changing spatial-temporal pattern of GPS measured crustal deformation rates along the central and southern Andes is governed by the relative importance of different phases of earthquake deformation cycle.

  1. REUSING STOCKS SOLUTIONS WITH DIFFERENT FORMULATED FOR ORCHID FERTILIZER ACCLIMATIZATION PHASE

    Directory of Open Access Journals (Sweden)

    C. G. C. Issa

    2018-04-01

    Full Text Available Orchids are ornamental plants that stand out by their colors, types, shapes, size, beauty. Additionally, some species have aromas. This diversity of orchids makes it be greatly appreciated as potted plants, landscaping, with high commercial value. The aim of this study was to evaluate the development of orchids at different levels of fertilization by reusing nutrients added to the culture medium for cultivation in vitro is also analyzing the different times of acclimatization. The micropropagated orchids removed from the growth chamber, were transported to greenhouse composing the different treatments for acclimatization (0, 10, 20, 30, 40 and 50 days. To be transplanted were placed in pine bark substrate and Sphagnum being placed in trays. After 30 days the seedlings were transplanted to styrofoam trays was initiated plant fertilization weekly with different formulated by administering 5 ml each (1 humic acid, 2nd potassium nitrate (KNO3, 3rd humic acid + Nitrate potassium (KNO3, 4th calcium chloride (CaCl2, 5 ° control. Six months after withdrawal of the growth room the plants was carried out the evaluation of the experiment where the plant survival was evaluated by the number of shoots, number of leaves, the length of the largest leaf and root presence. The experimental design was completely randomized in a factorial 6x5, with the time of acclimatization (0, 10, 20, 30, 40 and 50 days the first factor and the second, the type of fertilizer used (4 formulated and the witness with 8 replicates per treatment. The data were submitted to deviance analysis in the software R. In this study, the need to fertilize with nutrient rich formulations for orchids in the acclimatization phase was contacted and that these should remain for a few days inside the jars in a greenhouse environment.

  2. Differences in the Chemical Composition of the Particulate Phase of Inhaled and Exhaled Cigarette Mainstream Smoke

    Directory of Open Access Journals (Sweden)

    Moldoveanu SC

    2014-12-01

    Full Text Available In this study, a comparison between the chemical composition of the particulate-phase of exhaled smoke and that of smoke generated with a smoking machine has been performed. For this purpose, eight human subjects smoked a common Lights (10.6 mg ‘tar’/cig commercial cigarette and the exhaled particulate-phase smoke from three cigarettes was collected on Cambridge pads for each smoker. The smoke collection from the human subjects was vacuum assisted. The cigarette butts from the smokers were collected and analyzed for nicotine. The machine smoking was performed with a Borgwaldt RM20 CSR smoking machine working under conditions recommended by the U.S. Federal Trade Commission (FTC. The nicotine levels for the cigarette butts from the smokers were used to normalize the level of exhaled smoke condensate to that of the FTC smoking conditions. The smoke condensates from exhaled smoke as well as that from the machine smoking were analyzed by a gas chromatographic technique with mass spectral peak identification. The retention efficiency for 160 compounds was calculated from the ratio of the compound peak areas in the exhaled smoke (normalized by the corresponding butt nicotine level vs. the areas of the corresponding peaks from the chromatogram of the smoke generated by the smoking machine. In the calculation of the results, it was assumed that the composition of mainstream smoke remains practically constant at different smoking regimes. All compounds found in the machine-generated smoke were also present in the exhaled smoke, but at different levels. About one third of the compounds were retained more than 66% by the smoker. Another third of the compounds were retained between 33% and 66%, and the rest of the compounds were retained very little from the mainstream particulate-phase of the cigarette smoke. The compounds retained more than 66% were in general compounds with lower molecular weight and with higher water solubility, which eluted first

  3. PAHs levels in gas and particle-bound phase in schools at different locations in Serbia

    Directory of Open Access Journals (Sweden)

    Živković Marija

    2015-01-01

    Full Text Available This study investigated seasonal variation of PAHs and their partition between gas and particulate-bounded phases in indoor and outdoor air in 4 schools in Serbia located at different locations. The sampling campaigns were conducted during one workweek at each school successively. Campaigns were conducted in schools during heating and non-heating seasons in December 2011 and June 2012. Seasonal variations of gas and particle-bounded PAHs concentrations were observed with higher levels during heating season. The highest total PAH values were associated with the gas phase in both sampling periods. The total PAHs concentration at indoor and at the outdoor sites, during heating season, ranged from 88.45 to 447.72 ng/m3 and 201.69 to 1017.15 ng/m3, respectively. During non-heating season, the total PAHs concentration ranged from 36.91 to 271.57 ng/m3 in indoor environment and 27.00 to 132.32 ng/m3 in outdoor environment. Most of the I/O ratios were less than 1, which indicated that the indoor PAHs were mostly from outdoor sources. The use of diagnostic ratio showed that traffic emission and coal combustion are the major sources of PAHs. Only the diagnostic ratios for the school, located near the industrial area, showed significant deviation compared to other schools. [Projekat Ministarstva nauke Republike Srbije, br. TR33036: Development of new meteorological mast for turbulence parameters characterization and br. III42008: Evaluation of Energy Performances and Indoor Environment Quality of Educational Buildings in Serbia with Impact to Health

  4. Phenotypic diversity of diploid and haploid Emiliania huxleyi cells and of cells in different growth phases revealed by comparative metabolomics.

    Science.gov (United States)

    Mausz, Michaela A; Pohnert, Georg

    2015-01-01

    In phytoplankton a high species diversity of microalgae co-exists at a given time. But diversity is not only reflected by the species composition. Within these species different life phases as well as different metabolic states can cause additional diversity. One important example is the coccolithophore Emiliania huxleyi. Diploid cells play an important role in marine ecosystems since they can form massively abundant algal blooms but in addition the less abundant haploid life phase of E. huxleyi occurs in lower quantities. Both life phases may fulfill different functions in the plankton. We hypothesize that in addition to the functional diversity caused by this life phase transition the growth stage of cells can also influence the metabolic composition and thus the ecological impact of E. huxleyi. Here we introduce a metabolomic survey in dependence of life phases as well as different growth phases to reveal such changes. The comparative metabolomic approach is based on the extraction of intracellular metabolites from intact microalgae, derivatization and analysis by gas chromatography coupled to mass spectrometry (GC-MS). Automated data processing and statistical analysis using canonical analysis of principal coordinates (CAP) revealed unique metabolic profiles for each life phase. Concerning the correlations of metabolites to growth phases, complex patterns were observed. As for example the saccharide mannitol showed its highest concentration in the exponential phase, whereas fatty acids were correlated to stationary and sterols to declining phase. These results are indicative for specific ecological roles of these stages of E. huxleyi and are discussed in the context of previous physiological and ecological studies. Copyright © 2014 Elsevier GmbH. All rights reserved.

  5. Different impacts of mega-ENSO and conventional ENSO on the Indian summer rainfall: developing phase

    Science.gov (United States)

    Zhang, Lei; Wu, Zhiwei; Zhou, Yefan

    2016-04-01

    Mega-El Niño-Southern Oscillation (ENSO), a boarder version of conventional ENSO, is found to be a main driving force of Northern Hemisphere summer monsoon rainfall including the Indian summer rainfall (ISR). The simultaneous impacts of "pure" mega-ENSO and "pure" conventional ENSO events on the ISR in its developing summer remains unclear. This study examines the different linkages between mega-ENSO-ISR and conventional ENSO-ISR. During the developing summer of mega-El Niño, negative rainfall anomalies are seen over the northeastern Indian subcontinent, while the anomalous rainfall pattern is almost the opposite for mega-La Niña; as for the conventional ENSO, the approximate "linear opposite" phenomenon vanishes. Furthermore, the global zonal wave trains anomalous are found at mid-latitude zones, with a local triple circulation pattern over the central-east Eurasia during mega-ENSO events, which might be an explanation of corresponding rainfall response over the Indian Peninsula. Among 106-year historical run (1900-2005) of 9 state-of-the-art models from the Coupled Model Inter-comparison Project Phase 5 (CMIP5), HadGEM2-ES performs a promising skill in simulating the anomalous circulation pattern over mid-latitude and central-east Eurasia while CanESM2 cannot. Probably, it is the models' ability of capturing the mega-ENSO-ISR linkage and the characteristic of mega-ENSO that make the difference.

  6. Modern Evaluation of Liquisolid Systems with Varying Amounts of Liquid Phase Prepared Using Two Different Methods

    Directory of Open Access Journals (Sweden)

    Barbora Vraníková

    2015-01-01

    Full Text Available Liquisolid systems are an innovative dosage form used for enhancing dissolution rate and improving in vivo bioavailability of poorly soluble drugs. These formulations require specific evaluation methods for their quality assurance (e.g., evaluation of angle of slide, contact angle, or water absorption ratio. The presented study is focused on the preparation, modern in vitro testing, and evaluation of differences of liquisolid systems containing varying amounts of a drug in liquid state (polyethylene glycol 400 solution of rosuvastatin in relation to an aluminometasilicate carrier (Neusilin US2. Liquisolid powders used for the formulation of final tablets were prepared using two different methods: simple blending and spraying of drug solution onto a carrier in fluid bed equipment. The obtained results imply that the amount of liquid phase in relation to carrier material had an effect on the hardness, friability, and disintegration of tablets, as well as their height. The use of spraying technique enhanced flow properties of the prepared mixtures, increased hardness values, decreased friability, and improved homogeneity of the final dosage form.

  7. Association between different phases of menstrual cycle and body image measures of perceived size, ideal size, and body dissatisfaction.

    Science.gov (United States)

    Teixeira, André Luiz S; Dias, Marcelo Ricardo C; Damasceno, Vinícius O; Lamounier, Joel A; Gardner, Rick M

    2013-12-01

    The association between phases of the menstrual cycle and body image was investigated. 44 university women (M age = 23.3 yr., SD = 4.7) judged their perceived and ideal body size, and body dissatisfaction was calculated at each phase of the menstrual cycle, including premenstrual, menstrual, and intermenstrual. Participants selected one of nine figural drawings ranging from very thin to obese that represented their perceived size and ideal size. Body dissatisfaction was measured as the absolute difference between scores on perceived and ideal figural drawings. During each menstrual phase, anthropometric measures of weight, height, body mass index, circumference of waist and abdomen, and body composition were taken. There were no significant differences in any anthropometric measures between the three menstrual cycle phases. Perceived body size and body dissatisfaction were significantly different between menstrual phases, with the largest perceived body size and highest body dissatisfaction occurring during the menstrual phase. Ideal body size did not differ between menstrual phases, although participants desired a significantly smaller ideal size as compared to the perceived size.

  8. Force systems in the initial phase of orthodontic treatment -- a comparison of different leveling arch wires.

    Science.gov (United States)

    Fuck, Lars-Michael; Drescher, Dieter

    2006-01-01

    The determination of orthodontically-effective forces and moments places great demands on the technical equipment. Many patients report severe pain after fixed appliance insertion. Since it is assumed that pain from orthodontic appliances is associated with the force and moment levels applied to the teeth and since the occurrence of root resorption is a common therapeutic side effect, it would seem important to know the actual magnitudes of the components of the active orthodontic force systems. The aim of the present study was therefore to measure initial force systems produced by different leveling arch-wires in a complete multi-bracket appliance and to assess whether force and moment levels can be regarded as biologically acceptable or not. The actual bracket position in 42 patients was transferred onto a measurement model. Forces and moments produced by a super-elastic nickel-titanium (NiTi) archwire, a 6-strand stainless steel archwire, and a 7-strand super-elastic NiTi archwire were determined experimentally on different teeth. Average forces and moments produced by the super-elastic NiTi arch wires were found to be the highest. In spite if their larger diameter, the stranded arch wires' average force and moment levels were lower, especially that of the stranded super-elastic archwire. Nevertheless, maximum force levels sometimes exceeded recommended values in the literature and must be considered as too high. The measured arch wires' initial force systems differed significantly depending on the type of archwire and its material structure. Stranded arch wires produced lower force and moment levels, and we recommend their use in the initial phase of orthodontic treatment.

  9. Evolution of magnetotelluric, total magnetic field, and VLF field parameters in Central Italy. Relations to local seismic activity

    Energy Technology Data Exchange (ETDEWEB)

    Meloni, A.; Di Mauro, D.; Mele, G.; Palangio, P. [Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy); Ernst, T.; Teisseyre, R. [Institute of Geophysics, Warszawa (Poland)

    2001-04-01

    Magnetotelluric data were collected at Collemeluccio (41.72{sup 0}N, 14.37{sup 0}E) in Central Italy from summer 1991 to spring 1998. Analyzed by means of tensor decomposition on the geoelectric potential and robust estimation on the geomagnetic field, this set of data allowed the investigation of the electromagnetic induction, is presented here in its time evolution and compared to local and regional seismic activity. Tecto magnetic field observations from absolute magnetic field level in Central Italy were also made on data simultaneously recorded at four magnetometer stations, using L'Aquila Geomagnetic Observatory as a reference for differentiation. Recent results gathered from a system of two VLF search coil wide-band antennas, installed in the L'Aquila Observatory, are also discussed in relation to local seismic activity.

  10. SELF and VLF electromagnetic emissions that preceded the M6.2 Central Italy earthquake occurred on August 24, 2016

    Science.gov (United States)

    Cataldi, Daniele; Cataldi, Gabriele; Straser, Valentino

    2017-04-01

    On August 24, 2016 at 01:36:32 UTC a destructive earthquake hit Central Italy with a magnitude of M6.2. The authors of this study have recorded some electromagnetic signals that have preceded this strong earthquake. These signals were recorded through two electromagnetic monitoring stations realized by Gabriele Cataldi and Daniele Cataldi, located near the town of Albano Laziale (Rome, Italy) and near the city of Lariano (Rome, Italy) and can monitor the radio spectrum 24h7 between 0.001 Hz and 96 kHz (SELF-LF band). The electromagnetic monitoring allowed to identify two interesting types of electromagnetic anomalies: the first electromagnetic anomaly was recorded on August 18, 2016 between 02:47 UTC and 06:21 UTC, in the VLF band prevalently between 18kHz and 26kHz; the second electromagnetic anomaly was registered between 08:00 UTC on August 23, 2016 and 05:00 UTC on August 24, 2016, prevalently between 0.01 and 0.7Hz: the most intense signals were recorded at 08:50 UTC on August 23, 2016 and approximately 1 hour before the strong earthquake. The Earth's electromagnetic background monitoring in the SELF-VLF band (0HzM6+ earthquakes that occur on a global scale are always preceded by an increase of the solar wind proton density near Earth, the solar and geomagnetic activity monitoring is a seismic prediction method that has proven reliable for understanding when we can expect a recovery of the M6+ global seismic activity and could be used internationally as an indicator of seismic risk in the countries where there are potentially destructive earthquakes and tsunamis.

  11. Application of an advanced cost model in the different design phases of an offshore wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Hendriks, H.B.; Lindenburg, C.; Kooijman, H.J.T.; Bulder, B.H. [ECN Wind, Petten (Netherlands); Bozelie, J.; Madsen, J.B. [NEG Micon Holland, Rhenen (Netherlands); Halfschepel, R. [Van Oord ACZ, Gorinchem (Netherlands); Molenaar, W. [Ballast Nedam, Amstelveen (Netherlands); Van den Berg, R. [LM Glasfiber Holland, Heerhugowaard (Netherlands); Zaaijer, M. [TU-Delft, Delft (Netherlands)

    2001-09-01

    The goal of the Dutch Offshore Wind Energy Converter (DOWEC) consortium is to develop concepts and technology in order to make large scale offshore wind energy economically feasible. The overall DOWEC development comprises of the design, the construction, and the prototype testing. Onshore testing of a 3 MW research and development prototype is scheduled for the end of 2002. The DOWEC Concept Study aims at the choice of the optimal wind turbine concept. The wind turbine will not be treated as an isolated system. Designs of different wind turbine concepts will be evaluated as an integral part of the complete large-scale offshore wind farm. All significant properties like the structural loads, the power performance, the system reliability, the costs of the electric infrastructure, maintenance costs and installation costs is determined for the optimised designs. A quantitative ranking is then based on the cost of energy generated. Furthermore qualitative criteria like development risk and market potential will be taken into consideration when finalising the choice of concept. An advanced cost model is being developed to facilitate the above evaluation on basis of estimated energy generating costs for each concept. The same methodology will also be used in the system and detail design phase. This paper describes the DOWEC project in general, focusing at the cost modelling aspects including some preliminary results. 4 refs.

  12. Difference in quick phases induced by horizontal and vertical vestibular stimulations: role of the otolithic input.

    Science.gov (United States)

    Pettorossi, V E; Errico, P; Ferraresi, A

    1997-01-01

    Quick phases (QPs) induced by horizontal and vertical sinusoidal vestibular stimulations were studied in rabbits, cats, and humans. In all the animals, large and frequent horizontal QPs were observed following yaw stimulation in prone position. By contrast, QPs were almost absent during roll stimulation in rabbits, and they were small and oblique during pitch stimulation in cats and humans. As a result of these differences, the range of gaze displacement induced by vestibular stimulations was greater in the horizontal plane than in the vertical one. We also found that the trajectory of the QPs in rabbits was kept horizontal even when the yaw rotation was off vertical axis of +/- 45 degrees in the sagittal plane. Moreover, in the rabbit, the rare horizontal QPs induced by roll stimulation did not change their orientation at various pitch angles of roll stimulation axis. The QPs were also analyzed following roll stimulation of the rabbit in supine position. In this condition, in which the otolithic receptors were activated in the opposite way compared to prone position, large vertical QPs were elicited. We concluded that these results provide evidence that the otolithic signal plays a role in controlling occurrence and trajectory orientation of the QPs.

  13. Characteristics of cyprinid herpesvirus 3 in different phases of infection: implications for disease transmission and control.

    Science.gov (United States)

    Sunarto, Agus; McColl, Kenneth A; Crane, Mark St J; Schat, Karel A; Slobedman, Barry; Barnes, Andrew C; Walker, Peter J

    2014-08-08

    Koi herpesvirus disease (KHVD) is an emerging and highly contagious viral disease of koi and common carp (Cyprinus carpio), causing mass mortalities and huge economic losses to the carp aquaculture industry. The disease has spread rapidly to 28 countries worldwide. However, mechanisms of koi herpesvirus (species Cyprinid herpesvirus 3; CyHV-3) transmission remain unclear. A potential experimental model of CyHV-3 infection in carp was used to characterise CyHV-3 in different phases of infection and to demonstrate that CyHV-3 persists in survivor fish and has the capacity to reactivate and transmit the disease to healthy fish. During acute infection, which occurred when fish were maintained at 22°C, viral genes were abundantly expressed and infectious virus was produced in association with tissue damage, clinical disease and mortality. In fish maintained at a lower temperature (11°C), viral DNA was present but viral gene expression was absent or greatly restricted, infectious virus was not recovered and there was no evidence of disease. Productive replication was re-initiated following an increase in water temperature to 22°C, resulting in 45% mortality. Shedding of reactivated virus killed 75% of cohabitating naïve fish, suggesting a potential risk for disease transmission. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  14. Analysis and comparison of different phase shifters for Stirling pulse tube cryocooler

    DEFF Research Database (Denmark)

    Lei, Tian; Pfotenhauer, John M.; Zhou, Wenjie

    2016-01-01

    Investigations of phase shifters and power recovery mechanisms are of sustainable interest for developing Stirling pulse tube cryocoolers (SPTC) with higher power density, more compact design and higher efficiency. This paper investigates the phase shifting capacity and the applications of four...

  15. Comparison of single distance phase retrieval algorithms by considering different object composition and the effect of statistical and structural noise.

    Science.gov (United States)

    Chen, R C; Rigon, L; Longo, R

    2013-03-25

    Phase retrieval is a technique for extracting quantitative phase information from X-ray propagation-based phase-contrast tomography (PPCT). In this paper, the performance of different single distance phase retrieval algorithms will be investigated. The algorithms are herein called phase-attenuation duality Born Algorithm (PAD-BA), phase-attenuation duality Rytov Algorithm (PAD-RA), phase-attenuation duality Modified Bronnikov Algorithm (PAD-MBA), phase-attenuation duality Paganin algorithm (PAD-PA) and phase-attenuation duality Wu Algorithm (PAD-WA), respectively. They are all based on phase-attenuation duality property and on weak absorption of the sample and they employ only a single distance PPCT data. In this paper, they are investigated via simulated noise-free PPCT data considering the fulfillment of PAD property and weakly absorbing conditions, and with experimental PPCT data of a mixture sample containing absorbing and weakly absorbing materials, and of a polymer sample considering different degrees of statistical and structural noise. The simulation shows all algorithms can quantitatively reconstruct the 3D refractive index of a quasi-homogeneous weakly absorbing object from noise-free PPCT data. When the weakly absorbing condition is violated, the PAD-RA and PAD-PA/WA obtain better result than PAD-BA and PAD-MBA that are shown in both simulation and mixture sample results. When considering the statistical noise, the contrast-to-noise ratio values decreases as the photon number is reduced. The structural noise study shows that the result is progressively corrupted by ring-like artifacts with the increase of structural noise (i.e. phantom thickness). The PAD-RA and PAD-PA/WA gain better density resolution than the PAD-BA and PAD-MBA in both statistical and structural noise study.

  16. Circadian rhythm phase shifts and endogenous free-running circadian period differ between African-Americans and European-Americans.

    Science.gov (United States)

    Eastman, Charmane I; Suh, Christina; Tomaka, Victoria A; Crowley, Stephanie J

    2015-02-11

    Successful adaptation to modern civilization requires the internal circadian clock to make large phase shifts in response to circumstances (e.g., jet travel and shift work) that were not encountered during most of our evolution. We found that the magnitude and direction of the circadian clock's phase shift after the light/dark and sleep/wake/meal schedule was phase-advanced (made earlier) by 9 hours differed in European-Americans compared to African-Americans. European-Americans had larger phase shifts, but were more likely to phase-delay after the 9-hour advance (to phase shift in the wrong direction). The magnitude and direction of the phase shift was related to the free-running circadian period, and European-Americans had a longer circadian period than African-Americans. Circadian period was related to the percent Sub-Saharan African and European ancestry from DNA samples. We speculate that a short circadian period was advantageous during our evolution in Africa and lengthened with northern migrations out of Africa. The differences in circadian rhythms remaining today are relevant for understanding and treating the modern circadian-rhythm-based disorders which are due to a misalignment between the internal circadian rhythms and the times for sleep, work, school and meals.

  17. Spatial correlations and probability density function of the phase difference in a developed speckle-field: numerical and natural experiments

    International Nuclear Information System (INIS)

    Mysina, N Yu; Maksimova, L A; Ryabukho, V P; Gorbatenko, B B

    2015-01-01

    Investigated are statistical properties of the phase difference of oscillations in speckle-fields at two points in the far-field diffraction region, with different shapes of the scatterer aperture. Statistical and spatial nonuniformity of the probability density function of the field phase difference is established. Numerical experiments show that, for the speckle-fields with an oscillating alternating-sign transverse correlation function, a significant nonuniformity of the probability density function of the phase difference in the correlation region of the field complex amplitude, with the most probable values 0 and p, is observed. A natural statistical interference experiment using Young diagrams has confirmed the results of numerical experiments. (laser applications and other topics in quantum electronics)

  18. A comparison of different algorithms for phasing haplotypes using Holstein cattle genotypes and pedigree data.

    Science.gov (United States)

    Miar, Younes; Sargolzaei, Mehdi; Schenkel, Flavio S

    2017-04-01

    Phasing genotypes to haplotypes is becoming increasingly important due to its applications in the study of diseases, population and evolutionary genetics, imputation, and so on. Several studies have focused on the development of computational methods that infer haplotype phase from population genotype data. The aim of this study was to compare phasing algorithms implemented in Beagle, Findhap, FImpute, Impute2, and ShapeIt2 software using 50k and 777k (HD) genotyping data. Six scenarios were considered: no-parents, sire-progeny pairs, sire-dam-progeny trios, each with and without pedigree information in Holstein cattle. Algorithms were compared with respect to their phasing accuracy and computational efficiency. In the studied population, Beagle and FImpute were more accurate than other phasing algorithms. Across scenarios, phasing accuracies for Beagle and FImpute were 99.49-99.90% and 99.44-99.99% for 50k, respectively, and 99.90-99.99% and 99.87-99.99% for HD, respectively. Generally, FImpute resulted in higher accuracy when genotypic information of at least one parent was available. In the absence of parental genotypes and pedigree information, Beagle and Impute2 (with double the default number of states) were slightly more accurate than FImpute. Findhap gave high phasing accuracy when parents' genotypes and pedigree information were available. In terms of computing time, Findhap was the fastest algorithm followed by FImpute. FImpute was 30 to 131, 87 to 786, and 353 to 1,400 times faster across scenarios than Beagle, ShapeIt2, and Impute2, respectively. In summary, FImpute and Beagle were the most accurate phasing algorithms. Moreover, the low computational requirement of FImpute makes it an attractive algorithm for phasing genotypes of large livestock populations. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. Different phase delays of peripheral input to primate motor cortex and spinal cord promote cancellation at physiological tremor frequencies.

    Science.gov (United States)

    Koželj, Saša; Baker, Stuart N

    2014-05-01

    Neurons in the spinal cord and motor cortex (M1) are partially phase-locked to cycles of physiological tremor, but with opposite phases. Convergence of spinal and cortical activity onto motoneurons may thus produce phase cancellation and a reduction in tremor amplitude. The mechanisms underlying this phase difference are unknown. We investigated coherence between spinal and M1 activity with sensory input. In two anesthetized monkeys, we electrically stimulated the medial, ulnar, deep radial, and superficial radial nerves; stimuli were timed as independent Poisson processes (rate 10 Hz). Single units were recorded from M1 (147 cells) or cervical spinal cord (61 cells). Ninety M1 cells were antidromically identified as pyramidal tract neurons (PTNs); M1 neurons were additionally classified according to M1 subdivision (rostral/caudal, M1r/c). Spike-stimulus coherence analysis revealed significant coupling over a broad range of frequencies, with the strongest coherence at <50 Hz. Delays implied by the slope of the coherence phase-frequency relationship were greater than the response onset latency, reflecting the importance of late response components for the transmission of oscillatory inputs. The spike-stimulus coherence phase over the 6-13 Hz physiological tremor band differed significantly between M1 and spinal cells (phase differences relative to the cord of 2.72 ± 0.29 and 1.72 ± 0.37 radians for PTNs from M1c and M1r, respectively). We conclude that different phases of the response to peripheral input could partially underlie antiphase M1 and spinal cord activity during motor behavior. The coordinated action of spinal and cortical feedback will act to reduce tremulous oscillations, possibly improving the overall stability and precision of motor control. Copyright © 2014 the American Physiological Society.

  20. Effect of different factors on phase transformations in Fe-Mn alloys

    International Nuclear Information System (INIS)

    Balychev, Yu.M.; Tkachenko, F.K.

    1983-01-01

    Phase transformations proceeding under Fe-Mn alloy heating are studied and the effect of previous working conditions, particularly, cooling rate on these transformations is investigated. Investigations have been conducted on pure Fe-Mn alloys with 2-15% Mn. Phase transformations are shown to proceed according to α → #betta# and epsilon → #betta# reaction in Fe-Mn alloys containing 2-15% Mn under heating. Cooling rate in the range of approximately 5-1000 deg/min in preliminary working essentially affects phase transformations under subsequent heating

  1. Phase distortions in sum- and difference-frequency mixing in crystals

    International Nuclear Information System (INIS)

    Smith, A.V.; Bowers, M.S.

    1995-01-01

    We show that if two waves are incident on a quadratically nonlinear crystal, with the third wave generated entirely within the crystal, a phase-velocity mismatch (Δk ≠ 0) leads to intensity-dependent phase shifts of the generated wave only if there is walk-off, linear absorption, or significant diffraction of at least one of the waves as well as significant energy exchange among the waves. The result is frequency broadening and wave-front distortion of the generated wave. Although the induced phase distortions are usually quite small, they may be significant in applications that require high spectral resolution or pointing accuracy

  2. Effects of Phase Difference Between Axial and Contact loads on Fretting Fatigue Behavior of Titanium Alloy

    National Research Council Canada - National Science Library

    Almajali, Mohammad

    2006-01-01

    .... Most of the previous works were accomplished under a constant applied normal load and a little effort was done under a variable contact load, while none of these studies have considered the phase...

  3. Effect of normal and tumor factors on different phases of cell populations cycle.

    Science.gov (United States)

    Inda, A M; García, A L; Errecalde, A L; Badrán, A F

    1999-12-01

    In the present experiments we studied the effect of extracts from intact liver (LE), ES2 tumor extract (TE), plasmas from intact mice (PI), and from tumor bearing animals (PT) on different phases of hepatocytes and renocytes cell cycles. C3HS 28-day-old male mice, standardized for periodicity analysis, were injected at 16:00 hours and killed every 4 hours during a circadian cycle at 20:00/04; 00:00/08; 04:00/12; 08:00/16; 12:00/20 and 16:00/24 (time of day/hours post treatment). Colchicine (2 microg/g) was injected 4 hours before killing them. Samples of livers and kidneys were processed for histology and mitotic index determinations. The results were expressed as colchicine arrested metaphases per 1000 nuclei. The TE, LE and PI had a promoting effect on the mitotic activity of hepatocytes during the first 12 hours post treatment. During the subsequent 12 hours, not only these treatments but also the PI had an inhibiting effect on the mitotic activity of the same cell population. Also the TE and the PT had a promoting effect on the mitotic activity of the renocytes during the first 12 hours while the effect of all treatments showed a clear inhibition of the mitotic activity studied during the last 12 hours. Taking into account the time elapsed between the injections and the measurements made in these light-dark synchronized animals, we conclude that the increase in mitotic index observed in those tissues stemmed from a reinitiation of cell-cycle traverse in a subpopulation of G2-arrested, noncycling cells.

  4. An Approach to Preparing Ni-P with Different Phases for Use as Supercapacitor Electrode Materials.

    Science.gov (United States)

    Wang, Dan; Kong, Ling-Bin; Liu, Mao-Cheng; Luo, Yong-Chun; Kang, Long

    2015-12-01

    Herein, we describe a simple two-step approach to prepare nickel phosphide with different phases, such as Ni2 P and Ni5 P4 , to explain the influence of material microstructure and electrical conductivity on electrochemical performance. In this approach, we first prepared a Ni-P precursor through a ball milling process, then controlled the synthesis of either Ni2 P or Ni5 P4 by the annealing method. The as-prepared Ni2 P and Ni5 P4 are investigated as supercapacitor electrode materials for potential energy storage applications. The Ni2 P exhibits a high specific capacitance of 843.25 F g(-1) , whereas the specific capacitance of Ni5 P4 is 801.5 F g(-1) . Ni2 P possesses better cycle stability and rate capability than Ni5 P4 . In addition, the Fe2 O3 //Ni2 P supercapacitor displays a high energy density of 35.5 Wh kg(-1) at a power density of 400 W kg(-1) and long cycle stability with a specific capacitance retention rate of 96 % after 1000 cycles, whereas the Fe2 O3 //Ni5 P4 supercapacitor exhibits a high energy density of 29.8 Wh kg(-1) at a power density of 400 W kg(-1) and a specific capacitance retention rate of 86 % after 1000 cycles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Optimized determination of the radiological inventory during different phases of decommissioning

    International Nuclear Information System (INIS)

    Hillberg, Matthias; Beltz, Detlef; Karschnick, Oliver

    2012-01-01

    The decommissioning of nuclear facilities comprises a lot of activities such as decontamination, dismantling and demolition of equipment and structures. For these activities the aspects of health and safety of the operational personnel and of the general public as well as the minimization of radioactive waste have to be taken into account. An optimized, comprehensible and verifiable determination of the radiological inventory is essential for the decommissioning management with respect to safety, time, and costs. For example: right from the start of the post operational phase, the radiological characterization has to enable the decision whether to perform a system decontamination or not. Furthermore it is necessary, e.g. to determine the relevant nuclides and their composition (nuclide vector) for the release of material and for sustaining the radiological health and safety at work (e. g. minimizing the risk of incorporation). Our contribution will focus on the optimization of the radiological characterization with respect to the requisite extent and the best instant of time during the decommissioning process. For example: which additional information, besides the history of operation, is essential for an adequate amount of sampling and measurements needed in order to determine the relevant nuclides and their compositions? Furthermore, the characterization of buildings requires a kind of a graded approach during the decommissioning process. At the beginning of decommissioning, only a rough estimate of the expected radioactive waste due to the necessary decontamination of the building structures is sufficient. With ongoing decommissioning, a more precise radiological characterization of buildings is needed in order to guarantee an optimized, comprehensible and verifiable decontamination, dismantling and trouble-free clearance. These and other examples will be discussed on the background of and with reference to different decommissioning projects involving direct

  6. Modeling Sluggishness in Binaural Unmasking of Speech for Maskers With Time-Varying Interaural Phase Differences.

    Science.gov (United States)

    Hauth, Christopher F; Brand, Thomas

    2018-01-01

    In studies investigating binaural processing in human listeners, relatively long and task-dependent time constants of a binaural window ranging from 10 ms to 250 ms have been observed. Such time constants are often thought to reflect "binaural sluggishness." In this study, the effect of binaural sluggishness on binaural unmasking of speech in stationary speech-shaped noise is investigated in 10 listeners with normal hearing. In order to design a masking signal with temporally varying binaural cues, the interaural phase difference of the noise was modulated sinusoidally with frequencies ranging from 0.25 Hz to 64 Hz. The lowest, that is the best, speech reception thresholds (SRTs) were observed for the lowest modulation frequency. SRTs increased with increasing modulation frequency up to 4 Hz. For higher modulation frequencies, SRTs remained constant in the range of 1 dB to 1.5 dB below the SRT determined in the diotic situation. The outcome of the experiment was simulated using a short-term binaural speech intelligibility model, which combines an equalization-cancellation (EC) model with the speech intelligibility index. This model segments the incoming signal into 23.2-ms time frames in order to predict release from masking in modulated noises. In order to predict the results from this study, the model required a further time constant applied to the EC mechanism representing binaural sluggishness. The best agreement with perceptual data was achieved using a temporal window of 200 ms in the EC mechanism.

  7. Global diagnostics of the ionospheric perturbations related to the seismic activity using the VLF radio signals collected on the DEMETER satellite

    Directory of Open Access Journals (Sweden)

    O. Molchanov

    2006-01-01

    Full Text Available The analysis of the VLF signals radiated by ground transmitters and received on board of the French DEMETER satellite, reveals a drop of the signals (scattering spot connected with the occurrence of large earthquakes. The extension of the "scattering spots" zone is large enough (1000–5000 km and, probably, it increases with the magnitude of the "relative" earthquake. A possible model to explain the phenomenology, based on the acoustic gravity waves and the ionosphere turbulence, is proposed. The method of diagnostics applied to this study has the advantage to be a global one due to the world wide location of the powerful VLF transmitters and of the satellite reception. However, a specific disadvantage exists because the method requires rather a long time period of analysis due to the large longitudinal displacements among the successive satellite orbits. At the moment, at least, one month seems to be necessary.

  8. Tracheal sound parameters of respiratory cycle phases show differences between flow-limited and normal breathing during sleep

    International Nuclear Information System (INIS)

    Kulkas, A; Huupponen, E; Virkkala, J; Saastamoinen, A; Rauhala, E; Tenhunen, M; Himanen, S-L

    2010-01-01

    The objective of the present work was to develop new computational parameters to examine the characteristics of respiratory cycle phases from the tracheal breathing sound signal during sleep. Tracheal sound data from 14 patients (10 males and 4 females) were examined. From each patient, a 10 min long section of normal and a 10 min section of flow-limited breathing during sleep were analysed. The computationally determined proportional durations of the respiratory phases were first investigated. Moreover, the phase durations and breathing sound amplitude levels were used to calculate the area under the breathing sound envelope signal during inspiration and expiration phases. An inspiratory sound index was then developed to provide the percentage of this type of area during the inspiratory phase with respect to the combined area of inspiratory and expiratory phases. The proportional duration of the inspiratory phase showed statistically significantly higher values during flow-limited breathing than during normal breathing and inspiratory pause displayed an opposite difference. The inspiratory sound index showed statistically significantly higher values during flow-limited breathing than during normal breathing. The presented novel computational parameters could contribute to the examination of sleep-disordered breathing or as a screening tool

  9. Influence of bodybuilding classes on physical qualities of the qualified sportswomen in different phases of the specific biological cycle

    Directory of Open Access Journals (Sweden)

    Vyacheslav Mulik

    2017-02-01

    Full Text Available Purpose: to conduct researches of influence of classes of the sportswomen who are going in for bodybuilding and fitness-bikini on manifestation of physical qualities in different phases of the ovarian-menstrual cycle. Material & Methods: researches were conducted in sports fitness-clubs of Kharkov "Feromon", "Gorod", “King” with the qualified sportswomen who are going in for bodybuilding and fitness-bikini within 3 months of the preparatory period in number of 14 people. We used as methods of the research: the analysis of references and testing of level of motive qualities in separate phases of OMC. Results: the theoretical analysis of features of the accounting of phases of OMC at sportswomen is submitted and the testing of the level of development of physical qualities in different phases of the specific biological cycle at the qualified sportswomen, who are going in for bodybuilding, is held. Conclusions: the received results demonstrate that physical efficiency of the qualified sportswomen, who are going in for bodybuilding, is not identical in phases of the ovarian-menstrual cycle. It is revealed that the best conditions for performance of considerable exercise stresses in post-ovulatory and post-menstrual phases of OMC, therefore it is expedient to plan them in the preparatory periods of the qualified sportswomen, who are going in for bodybuilding.

  10. HIV Prevention among Mexican Migrants at Different Migration Phases: Exposure to Prevention Messages and Association With Testing Behaviors

    Science.gov (United States)

    Martinez-Donate, Ana P.; Rangel, M. Gudelia; Zhang, Xiao; Simon, Norma-Jean; Rhoads, Natalie; Gonzalez-Fagoaga, J. Eduardo; Gonzalez, Ahmed Asadi

    2016-01-01

    Mobile populations are at increased risk for HIV infection. Exposure to HIV prevention messages at all phases of the migration process may help decrease im/migrants’ HIV risk. We investigated levels of exposure to HIV prevention messages, factors associated with message exposure, and the association between exposure to prevention messages and HIV testing behavior among Mexican im/migrants at different phases of the migration process. We conducted a cross-sectional, probability survey of Mexican im/migrants (N=3,149) traveling through the border city of Tijuana, Mexico. The results indicate limited exposure to prevention messages (57%–75%) and suboptimal last 12-month HIV testing rates (14%–25%) across five migration phases. Compared to pre-departure levels (75%), exposure to messages decreases at all post-departure migration phases (57%–63%, pmigration continuum. PMID:26595267

  11. Gibbs free energy difference between the undercooled liquid and the beta phase of a Ti-Cr alloy

    Science.gov (United States)

    Ohsaka, K.; Trinh, E. H.; Holzer, J. C.; Johnson, W. L.

    1992-01-01

    The heat of fusion and the specific heats of the solid and liquid have been experimentally determined for a Ti60Cr40 alloy. The data are used to evaluate the Gibbs free energy difference, delta-G, between the liquid and the beta phase as a function of temperature to verify a reported spontaneous vitrification (SV) of the beta phase in Ti-Cr alloys. The results show that SV of an undistorted beta phase in the Ti60Cr40 alloy at 873 K is not feasible because delta-G is positive at the temperature. However, delta-G may become negative with additional excess free energy to the beta phase in the form of defects.

  12. Effect of D.C. testing water tree deteriorated cable and a preliminary evaluation of V.L.F. as alternate

    International Nuclear Information System (INIS)

    Eager, G.S. Jr.; Fryszczyn, B.; Katz, C.; ElBadaly, H.A.; Jean, A.R.

    1992-01-01

    This paper reports that according to the experience of some power utilities, the application of industry recommended high voltage d.c. field tests on 5-35 kV extruded dielectric cables, containing water trees, sometimes causes further deterioration of the insulation. Tests conducted on laboratory aged 15 kV ethylene propylene rubber (EP) and 15 and 28 kV crosslinked polyethylene (XLPE) insulated cables indicate that d.c. proof tests in accordance with AEIC specifications an IEEE test guides without flashover do not appear to cause further deterioration. Depending on the degree of cable aging and the level of test voltage, when flashovers take place, damage may be inflicted to XLPE cables. No damage was observed on aged EP cable, at the same test levels. Because of the aforementioned power utility experience, some users have requested an alternate field proof test. Tests conducted on new XLPE and EP cables indicate that damage to the insulation structure can be detected using VLF (0.1 Hz) voltage at approximately one-third the d.c. voltage level. Field tests conducted on severely tree deteriorated 15 kV polyethylene (PE) cable using AEIC recommended d.c. voltage level of about five times operating voltage level caused cable failure; VLF voltage levels up to two times operating voltage did not. VLF voltage appears to be a suitable alternate to d.c. voltage for field proof testing

  13. Differing results of direct and indirect solid phase radioimmunoassay for HBsAg in acute hepatitis

    International Nuclear Information System (INIS)

    Strohm, W.D.; Legler, K.; Gerlich, W.; Stamm, B.; Zimmer, S.; Biotest-Serum-Institut G.m.b.H., Frankfurt am Main; Goettingen Univ.

    1978-01-01

    In 54 patients suffering from active viral hepatitis the indirect solid phase radioimmunoassay (ind-SPRIA) for HBsAg was positive in 9 cases the direct solid phase radioimmunoassay (d-SPRIA) being negative. In 2 further cases ind-SPRIA was positive during several weeks but d-SPRIA only once. AntiHBc could be detected in 9 of these patients. In 7 patients the usual decrease of the transaminase activity was followed by a second elavation with prolongation of the disease. The unknown factor detected by ind-SPRIA suggests a special of acute hepatitis. (orig.) [de

  14. Performance Evaluation of Eleven-Phase Induction Machine with Different PWM Techniques

    Directory of Open Access Journals (Sweden)

    M.I. Masoud

    2015-06-01

    Full Text Available Multiphase induction machines are used extensively in low and medium voltage (MV drives. In MV drives, power switches have a limitation associated with switching frequency. This paper is a comparative study of the eleven-phase induction machine’s performance when used as a prototype and fed sinusoidal pulse-width-modulation (SPWM with a low switching frequency, selective harmonic elimination (SHE, and single pulse modulation (SPM techniques. The comparison depends on voltage/frequency controls for the same phase of voltage applied on the machine terminals for all previous techniques. The comparative study covers torque ripple, stator and harmonic currents, and motor efficiency.

  15. Differing results of direct and indirect solid phase radioimmunoassay for HBsAg in acute hepatitis

    Energy Technology Data Exchange (ETDEWEB)

    Strohm, W D; Legler, K; Gerlich, W; Stamm, B; Zimmer, S [Frankfurt Univ. (Germany, F.R.). Abt. fuer Gastroenterologie; Biotest-Serum-Institut G.m.b.H., Frankfurt am Main (Germany, F.R.); Goettingen Univ. (Germany, F.R.). Hygiene-Institut)

    1978-09-01

    In 54 patients suffering from active viral hepatitis the indirect solid phase radioimmunoassay (ind-SPRIA) for HBsAg was positive in 9 cases the direct solid phase radioimmunoassay (d-SPRIA) being negative. In 2 further cases ind-SPRIA was positive during several weeks but d-SPRIA only once. AntiHBc could be detected in 9 of these patients. In 7 patients the usual decrease of the transaminase activity was followed by a second elavation with prolongation of the disease. The unknown factor detected by ind-SPRIA suggests a special of acute hepatitis.

  16. Automatic frequency and phase alignment of in vivo J-difference-edited MR spectra by frequency domain correlation.

    Science.gov (United States)

    Wiegers, Evita C; Philips, Bart W J; Heerschap, Arend; van der Graaf, Marinette

    2017-12-01

    J-difference editing is often used to select resonances of compounds with coupled spins in 1 H-MR spectra. Accurate phase and frequency alignment prior to subtracting J-difference-edited MR spectra is important to avoid artefactual contributions to the edited resonance. In-vivo J-difference-edited MR spectra were aligned by maximizing the normalized scalar product between two spectra (i.e., the correlation over a spectral region). The performance of our correlation method was compared with alignment by spectral registration and by alignment of the highest point in two spectra. The correlation method was tested at different SNR levels and for a broad range of phase and frequency shifts. In-vivo application of the proposed correlation method showed reduced subtraction errors and increased fit reliability in difference spectra as compared with conventional peak alignment. The correlation method and the spectral registration method generally performed equally well. However, better alignment using the correlation method was obtained for spectra with a low SNR (down to ~2) and for relatively large frequency shifts. Our correlation method for simultaneously phase and frequency alignment is able to correct both small and large phase and frequency drifts and also performs well at low SNR levels.

  17. Measurement of the phase difference between short- and long-distance amplitudes in the [Formula: see text] decay.

    Science.gov (United States)

    Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baszczyk, M; Batozskaya, V; Batsukh, B; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Berezhnoy, A; Bernet, R; Bertolin, A; Betancourt, C; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, Ia; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Bordyuzhin, I; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cavallero, G; Cenci, R; Chamont, D; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C-T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Dendek, A; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Fazzini, D; Ferguson, D; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Funk, W; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hatch, M; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, H; Hulsbergen, W; Humair, T; Hushchyn, M; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Koliiev, S; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kosmyntseva, A; Kozachuk, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, T; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marinangeli, M; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurice, E; Maurin, B; Mazurov, A; McCann, M; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Morgunova, O; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, T D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Nogay, A; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palombo, F; Palutan, M; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Placinta, V; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Popov, A; Popov, D; Popovici, B; Poslavskii, S; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Ratnikov, F; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Soares Lavra, L; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stevens, H; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vernet, M; Vesterinen, M; Viana Barbosa, J V; Viaud, B; Vieira, D; Vieites Diaz, M; Viemann, H; Vilasis-Cardona, X; Vitti, M; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yao, Y; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhang, Y; Zhelezov, A; Zheng, Y; Zhu, X; Zhukov, V; Zucchelli, S

    2017-01-01

    A measurement of the phase difference between the short- and long-distance contributions to the [Formula: see text] decay is performed by analysing the dimuon mass distribution. The analysis is based on pp collision data corresponding to an integrated luminosity of 3[Formula: see text] collected by the LHCb experiment in 2011 and 2012. The long-distance contribution to the [Formula: see text] decay is modelled as a sum of relativistic Breit-Wigner amplitudes representing different vector meson resonances decaying to muon pairs, each with their own magnitude and phase. The measured phases of the [Formula: see text] and [Formula: see text] resonances are such that the interference with the short-distance component in dimuon mass regions far from their pole masses is small. In addition, constraints are placed on the Wilson coefficients, [Formula: see text] and [Formula: see text], and the branching fraction of the short-distance component is measured.

  18. Nonequilibrium capillarity effects in two?phase flow through porous media at different scales

    NARCIS (Netherlands)

    Bottero, S.; Hassanizadeh, S.M.; Kleingeld, P.J.; Heimovaara, T.J.

    2011-01-01

    A series of primary drainage experiments was carried out in order to investigate nonequilibrium capillarity effects in two?phase flow through porous media. Experiments were performed with tetrachloroethylene (PCE) and water as immiscible fluids in a sand column 21 cm long. Four drainage experiments

  19. Nonequilibrium capillarity effects in two-phase flow through porous media at different scales

    NARCIS (Netherlands)

    Bottero, S.; Hassanizadeh, S.M.; Kleingeld, P.J.; Heimovaara, T.J.

    2011-01-01

    A series of primary drainage experiments was carried out in order to investigate nonequilibrium capillarity effects in two-phase flow through porous media. Experiments were performed with tetrachloroethylene (PCE) and water as immiscible fluids in a sand column 21 cm long. Four drainage experiments

  20. Critical micelle concentration values for different surfactants measured with solid-phase microextraction fibers

    NARCIS (Netherlands)

    Haftka, Joris J H; Scherpenisse, Peter; Oetter, G??nter; Hodges, Geoff; Eadsforth, Charles V.; Kotthoff, Matthias; Hermens, Joop L M

    The amphiphilic nature of surfactants drives the formation of micelles at the critical micelle concentration (CMC). Solid-phase microextraction (SPME) fibres were used in the present study to measure CMC values of twelve nonionic, anionic, cationic and zwitterionic surfactants. The SPME derived CMC

  1. Crystal Analysis of Multi Phase Calcium Phosphate Nanoparticles Containing Different amount of Magnesium

    Science.gov (United States)

    Gozalian, Afsaneh; Behnamghader, Ali Asghar; Moshkforoush, Arash

    In this study, Mg doped hydroxyapatite [(Ca, Mg)10(PO4)6(OH)2] and β-tricalcium phosphate nanoparticles were synthesized via sol gel method. Triethyl phosphite, calcium nitrate tetrahydrate and magnesium nitrate hexahydrate were used as P, Ca and Mg precursors. The ratio of (Ca+Mg)/P and the amount of magnesium (x) were kept constant at 1.67 and ranging x = 0 up to 3 in molecular formula of Ca10-xMgx (PO4)6(OH)2, respectively. Phase composition and chemical structure were performed using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Phase percentages, crystallite size, degree of crystallinity and lattice parameters were investigated. The presence of magnesium led to form the Mg doped tricalcium phosphate (β-TCMP) and Mg doped hydroxyapatite (Mg-HA). Based on the results of this study, lattice parameters, degree of crystallinity and crystallite size decreased with magnesium content. In addition, with increasing magnesium content, the amount of CaO phase decreased whereas the amount of MgO phase increased significantly. Obtained results can be used for new biomaterials design.

  2. Composition of essential oil of costmary [Balsamita major (L.) Desf.] at different growth phases

    NARCIS (Netherlands)

    Bylaite, E.; Venskutonis, R.; Roozen, J.P.; Posthumus, M.A.

    2000-01-01

    The essential oils from leaves and flowers of costmary, Balsamita major (L.) Desf. (syn. Chrysanthemum balsamita L.), were analyzed at various phases of plant growth. The highest contents of oil both in leaves and in flowers were determined before full blooming, 1.15 and 1.34øw/w), respectively.

  3. The Italian National Forest Inventory: geographical and positioning aspects in relation to the different phases of the project

    Science.gov (United States)

    Giacomo Colle; Antonio Floris; Gianfranco Scrinzi; Giovanni Tabacchi; Lorenzo Cavini

    2009-01-01

    In this article, we describe in depth the analysis and solutions to manage the multiple coordinates of the sampling objects coming from the three different phases of the second Italian national forest inventory (Inventario Nazionale delle Foreste e dei serbatoi forestali di Carbonio [INFC]). In particular, this article describes the criteria used to determine the...

  4. Study of inter-modal four wave mixing in two few-mode fibres with different phase matching properties

    DEFF Research Database (Denmark)

    Parmigiani, F.; Jung, Y.; Friis, Søren Michael Mørk

    2016-01-01

    We experimentally study inter-modal four-wave mixing (FWM) in few-mode fibres with different phase matching properties. The possibility of transmitting two spatial modes without intermodal FWM cross-talk in the C-band is presented....

  5. 7T T-2*-weighted magnetic resonance imaging reveals cortical phase differences between early- and late-onset Alzheimer's disease

    NARCIS (Netherlands)

    van Rooden, S.; Doan, N.T.; Versluis, M.J.; Goos, J.D.C.; Webb, A.G.; Oleksik, A.M.; van der Flier, W.M.; Scheltens, P.; Barkhof, F.; Weverlinge-Rynsburger, A.W.E.; Blauw, G. J.; Reiber, J.H.C.; van Buchem, M.A.; Milles, J.; van der Grond, J.

    2015-01-01

    The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of Alzheimer's disease pathology, between early- and late-onset Alzheimer's disease (EOAD, LOAD, respectively) patients using 7T magnetic resonance phase images. High-resolution T

  6. Effect of Different Training Methods on Stride Parameters in Speed Maintenance Phase of 100-m Sprint Running.

    Science.gov (United States)

    Cetin, Emel; Hindistan, I Ethem; Ozkaya, Y Gul

    2018-05-01

    Cetin, E, Hindistan, IE, Ozkaya, YG. Effect of different training methods on stride parameters in speed maintenance phase of 100-m sprint running. J Strength Cond Res 32(5): 1263-1272, 2018-This study examined the effects of 2 different training methods relevant to sloping surface on stride parameters in speed maintenance phase of 100-m sprint running. Twenty recreationally active students were assigned into one of 3 groups: combined training (Com), horizontal training (H), and control (C) group. Com group performed uphill and downhill training on a sloping surface with an angle of 4°, whereas H group trained on a horizontal surface, 3 days a week for 8 weeks. Speed maintenance and deceleration phases were divided into distances with 10-m intervals, and running time (t), running velocity (RV), step frequency (SF), and step length (SL) were measured at preexercise, and postexercise period. After 8 weeks of training program, t was shortened by 3.97% in Com group, and 2.37% in H group. Running velocity also increased for totally 100 m of running distance by 4.13 and 2.35% in Com, and H groups, respectively. At the speed maintenance phase, although t and maximal RV (RVmax) found to be statistically unaltered during overall phase, t was found to be decreased, and RVmax was preceded by 10 m in distance in both training groups. Step length was increased at 60-70 m, and SF was decreased at 70-80 m in H group. Step length was increased with concomitant decrease in SF at 80-90 m in Com group. Both training groups maintained the RVmax with a great percentage at the speed maintenance phase. In conclusion, although both training methods resulted in an increase in running time and RV, Com training method was more prominently effective method in improving RV, and this improvement was originated from the positive changes in SL during the speed maintaining phase.

  7. Ambiguity resolving based on cosine property of phase differences for 3D source localization with uniform circular array

    Science.gov (United States)

    Chen, Xin; Wang, Shuhong; Liu, Zhen; Wei, Xizhang

    2017-07-01

    Localization of a source whose half-wavelength is smaller than the array aperture would suffer from serious phase ambiguity problem, which also appears in recently proposed phase-based algorithms. In this paper, by using the centro-symmetry of fixed uniform circular array (UCA) with even number of sensors, the source's angles and range can be decoupled and a novel ambiguity resolving approach is addressed for phase-based algorithms of source's 3-D localization (azimuth angle, elevation angle, and range). In the proposed method, by using the cosine property of unambiguous phase differences, ambiguity searching and actual-value matching are first employed to obtain actual phase differences and corresponding source's angles. Then, the unambiguous angles are utilized to estimate the source's range based on a one dimension multiple signal classification (1-D MUSIC) estimator. Finally, simulation experiments investigate the influence of step size in search and SNR on performance of ambiguity resolution and demonstrate the satisfactory estimation performance of the proposed method.

  8. Assessment of intersegmental coordination of rats during walking at different speeds - Application of continuous relative phase

    DEFF Research Database (Denmark)

    Raffalt, Peter Christian; Nielsen, Louise R; Madsen, Stefan

    2018-01-01

    of the CRP (ACRP) and DP and on the mean ACRP and mean DP was established by statistical parametric mapping (SPM) and a one-way ANOVA for repeated measures. Absolute and relative reliability were assessed by measurement error and intra-class correlation coefficient. The SPM analysis revealed time dependent......The present study investigated the feasibility and reliability of continuous relative phase (CRP) and deviation phase (DP) to assess intersegmental hind limb coordination pattern and coordination variability in rats during walking. Twenty-six adult rats walked at 8 m/min, 12 m/min and 16 m....../min while two-dimensional kinematics were recorded. Segment angles and segment angular velocities of the paw, shank and thigh on the left hind-limb were extracted from 15 strides and CRP was calculated for the paw-shank and shank-thigh coupling. The effect of walking speed on the time point average curve...

  9. Red Guava Leaf Harvesting Impact on Flavonoid Optimation in Different Growth Phases

    Directory of Open Access Journals (Sweden)

    MUNIF GHULAMAHDI

    2011-06-01

    Full Text Available Harvesting process is a critical time to identify the quality of raw material for traditional medicine. The time and harvesting techniques, drying process after harvesting, and processing to make the simplicia, are the crucial role to make the good quality of the natural product. On the other hand, there is a lack of general understanding and appreciation about the processes involved in governing shoot and tree growth and development, i.e. red guava. The research objective was to evaluate the influence of leaf harvesting and growth phases on red guava for flavonoid production as antioxidant. Randomized factorial block design in time were laid out with two factors and followed by Duncan’s multiple range test. The treatments were the amount of leaf harvested on tertiary branches (0, 25, 50, and 100% and growth phases of the plant (vegetative and generative. Leaf harvesting 25% on tertiary branches significantly increased the leaf number (766.3 tree-1 and the number of new quarternary branches, decreasing leaf area index (LAI and leaf dry weight at the end of the experiment (22 weeks of observation/WO. The highest leaf dry weight (156.94 g tree-1 and LAI (0.47 was found in harvesting 25% tertiary branches. Harvesting 100% leaf on tertiary branches in vegetative phase significantly produced the lowest flavonoid production (7.82 g tree-1. The result suggested that flavonoid production from red guava leaves should be done by harvesting 50% leaf on tertiary branches in generative phase can be used to produce the highest flavonoid (89.90 g tree-1.

  10. Phase and Micro-Structural Characterization of Sanitary-Ware Fired at Different Temperature

    OpenAIRE

    ATHER HASSAN; YASEEN IQBAL; SYED ZAFAR ILYAS

    2017-01-01

    The three main ingredients of sanitary-ware are clay, feldspar and quartz. This ware is being widely used and has therefore, attracted the attention of researchers from time to time. Consequently, it has been extensively investigated. The present study describes the phase and micro-structural analysis of sanitary-ware samples collected from local (Durr Ceramics Peshawar) industry. XRD (X-Ray Diffraction) of samples fired at 1100oC reveals the presence of ? ? ? ? ?-quartz and primary mullite o...

  11. Selective Interareal Synchronization through Gamma Frequency Differences and Slower-Rhythm Gamma Phase Reset.

    Science.gov (United States)

    Burwick, Thomas; Bouras, Alexandros

    2017-03-01

    The communication-through-coherence (CTC) hypothesis states that a sending group of neurons will have a particularly strong effect on a receiving group if both groups oscillate in a phase-locked ("coherent") manner (Fries, 2005 , 2015 ). Here, we consider a situation with two visual stimuli, one in the focus of attention and the other distracting, resulting in two sites of excitation at an early cortical area that project to a common site in a next area. Taking a modeler's perspective, we confirm the workings of a mechanism that was proposed by Bosman et al. ( 2012 ) in the context of providing experimental evidence for the CTC hypothesis: a slightly higher gamma frequency of the attended sending site compared to the distracting site may cause selective interareal synchronization with the receiving site if combined with a slow-rhythm gamma phase reset. We also demonstrate the relevance of a slightly lower intrinsic frequency of the receiving site for this scenario. Moreover, we discuss conditions for a transition from bottom-up to top-down driven phase locking.

  12. Qualitative and quantitative analysis of different fluid phase in samples of glass beads by X-ray microtomography

    International Nuclear Information System (INIS)

    Marques, Leonardo C.; Nagata, Rodrigo; Appoloni, Carlos R.; Moreira, Anderson C.; Fernanades, Celso P.

    2011-01-01

    The X-ray microtomography has showed to be a useful tool for studies of inner structure of reservoir rocks. Moreover recent works have used this methodology to visualize different fluid phases present in these microstructures. In this paper X-ray microtomography has been applied to visualize three fluid phases, separately or simultaneously, in addition to a solid phase (glass beads). Two glass beads samples were manufactured and scanned, one with 0.8 mm (GB1) and other with 0.6 mm (GB2) diameter, respectively. The three fluid phases used were air, oil and a water-salt-potassium iodine solution. Two Skyscan scanners were used, both a 1172 model, which employs X-ray tube with W anode and cone beam. This laboratory based equipment is able to provide images of until 1 μm spatial resolution. One microtomograph is located at CENPES/PETROBRAS and has a CCD camera of 10 mega pixels resolution. It was used to measure the GB1 sample at 4.84 μm spatial resolution. The other one is located at LAMIR/UFPR and has a CCD camera of 11 mega pixels resolution. It was used to measure the GB2 sample at 4.99 μm spatial resolution. GB1 sample was set up with three fluid phases and presented 38.0 (2.7) % of total porosity before fluid presence and 3.5 % and 19.8 %, as lower and higher average porosity values, respectively, after to be filled with them. GB2 sample was set up with oil and water-salt-potassium iodine solution separated. It presented 36.7 (1.9) % of total porosity when dried, 18.7 (2.0) % when filled with oil and 0 % when filled with the solution. The 2D images clearly show the presence of the solution in addition to the air and solid phases. They also show that the presence of oil phase is less clear than the solution. When all the phases are present together in the sample it is possible to differentiate all of them. Individual 3D images are shown for each phase present in the sample. The 3D image containing all the phases is also shown. (author)

  13. Detection of cerebral hemorrhage in rabbits by time-difference magnetic inductive phase shift spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wencai Pan

    Full Text Available Cerebral hemorrhage, a difficult issue in clinical practice, is often detected and studied with computed tomography (CT, magnetic resonance imaging (MRI, and positron emission tomography (PET. However, these expensive devices are not readily available in economically underdeveloped regions, and hence are unable to provide bedside and emergency on-site monitoring. The magnetic inductive phase shift (MIPS is an emerging technology that may become a new tool to detect cerebral hemorrhage and to serve as an inexpensive partial substitute to medical imaging. In order to study a wider band of cerebral hemorrhage MIPS and to provide more useful information for measuring cerebral hemorrhage, we established a cerebral hemorrhage magnetic induction phase shift spectroscopy (MIPSS detection system. Thirteen rabbits with five cerebral hemorrhage states were studied using a single coil-coil within a 1 MHz-200 MHz frequency range in linear sweep. A feature band (FB with the highest detection sensitivity and the greatest stability was selected for further analysis and processing. In addition, a maximum conductivity cerebrospinal fluid (CSF MRI was performed to verify and interpret the MIPSS result. The average phase shift change induced by a 3 ml injection of autologous blood under FB was -7.7503° ± 1.4204°, which was considerably larger than our previous work. Data analysis with a non-parametric statistical Friedman M test showed that in the FB, MIPSS could distinguish the five states of cerebral hemorrhage in rabbits, with a statistical significance of p<0.05. A B-F distribution profile was designed according to the MIPSS under FB that can provide instantaneous diagnostic information about the cerebral hemorrhage severity from a single set of measurements. The results illustrate that the MIPSS detection method is able to provide a new possibility for real-time monitoring and diagnosis of the severity of cerebral hemorrhage.

  14. Detection of Cerebral Hemorrhage in Rabbits by Time-Difference Magnetic Inductive Phase Shift Spectroscopy

    Science.gov (United States)

    Pan, Wencai; Yan, Qingguang; Qin, Mingxin; Jin, Gui; Sun, Jian; Ning, Xu; Zhuang, Wei; Peng, Bin; Li, Gen

    2015-01-01

    Cerebral hemorrhage, a difficult issue in clinical practice, is often detected and studied with computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). However, these expensive devices are not readily available in economically underdeveloped regions, and hence are unable to provide bedside and emergency on-site monitoring. The magnetic inductive phase shift (MIPS) is an emerging technology that may become a new tool to detect cerebral hemorrhage and to serve as an inexpensive partial substitute to medical imaging. In order to study a wider band of cerebral hemorrhage MIPS and to provide more useful information for measuring cerebral hemorrhage, we established a cerebral hemorrhage magnetic induction phase shift spectroscopy (MIPSS) detection system. Thirteen rabbits with five cerebral hemorrhage states were studied using a single coil-coil within a 1 MHz-200 MHz frequency range in linear sweep. A feature band (FB) with the highest detection sensitivity and the greatest stability was selected for further analysis and processing. In addition, a maximum conductivity cerebrospinal fluid (CSF) MRI was performed to verify and interpret the MIPSS result. The average phase shift change induced by a 3 ml injection of autologous blood under FB was -7.7503° ± 1.4204°, which was considerably larger than our previous work. Data analysis with a non-parametric statistical Friedman M test showed that in the FB, MIPSS could distinguish the five states of cerebral hemorrhage in rabbits, with a statistical significance of phemorrhage severity from a single set of measurements. The results illustrate that the MIPSS detection method is able to provide a new possibility for real-time monitoring and diagnosis of the severity of cerebral hemorrhage. PMID:26001112

  15. Ionospheric perturbations due to earthquakes as determined from VLF and GPS-TEC data analysis at Agra, India

    Science.gov (United States)

    Singh, Dhananjali; Singh, Birbal; Pundhir, Devbrat

    2018-04-01

    Employing SoftPAL receiver, amplitude variations of VLF transmitter signals NWC (19.8 kHz) and NPM (21.4 kHz) are analyzed at Agra station in India (Geograph. lat. 27.2°N, long. 78°E) ±15 days from five major earthquakes of magnitude M = 6.9-8.5 occurred in Indian subcontinent during the years 2011-2013. We apply nighttime fluctuation (NF) method and show that in almost all cases the trend decreases and dispersion and NF increase on the same days corresponding to each earthquake about 11-15 days prior to the main shock. Assuming that the ionospheric perturbations are caused by atmospheric gravity waves (AGW), we also calculate AGW modulation index for each case and find its values increased on the days amplitude fluctuations take place. Its value is decreased in one case only where the perturbations may be attributed to penetration of seismogenic electric field. In order to support the above results we also present GPS-TEC data analyzed by us corresponding to three of the above earthquakes. We study the TEC anomalies (unusual enhancements) and find that in one case the precursory period is almost the same as that found in NF method.

  16. The role of the entry-and-stretch phase at the different paces of race in front crawl swimming.

    Science.gov (United States)

    Samson, Mathias; Monnet, Tony; Bernard, Anthony; Lacouture, Patrick; David, Laurent

    2015-01-01

    The aim of this study was to determine the role played by the entry-and-stretch phase in the coordination of swimming, at the different paces of race. Three national level swimmers (two men and one woman) were recorded, in lateral and bottom views, in three swimming paces: sprint (50 m and 100 m), middle-distance (200 m and 400 m) and long-distance (800 m and 1500 m). Anatomical landmark positions were obtained by manual digitalisation of the videos. Computational fluid dynamics and experimental studies (with a strain gauge balance and particle image velocimetry method) were used to measure and to calculate the external forces applied to the hand and to the forearm and to visualise the flow around the profile. Entry-and-stretch is the phase which varies the most according to the swimming pace. This phase can be decomposed into two sub-phases: one, the extension forward coordinated with the insweep of the opposite arm, and another one, the rotation downward coordinated with the upsweep. Results show that, at the three paces, this phase is not propulsive and could contribute essentially to maintain the horizontal balance of the body.

  17. 7T T₂*-weighted magnetic resonance imaging reveals cortical phase differences between early- and late-onset Alzheimer's disease.

    Science.gov (United States)

    van Rooden, Sanneke; Doan, Nhat Trung; Versluis, Maarten J; Goos, Jeroen D C; Webb, Andrew G; Oleksik, Ania M; van der Flier, Wiesje M; Scheltens, Philip; Barkhof, Frederik; Weverling-Rynsburger, Annelies W E; Blauw, Gerard Jan; Reiber, Johan H C; van Buchem, Mark A; Milles, Julien; van der Grond, Jeroen

    2015-01-01

    The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of Alzheimer's disease pathology, between early- and late-onset Alzheimer's disease (EOAD, LOAD, respectively) patients using 7T magnetic resonance phase images. High-resolution T2(∗)-weighted scans were acquired in 12 EOAD patients and 17 LOAD patients with mild to moderate disease and 27 healthy elderly control subjects. Lobar peak-to-peak phase shifts and regional mean phase contrasts were computed. An increased peak-to-peak phase shift was found for all lobar regions in EOAD patients compared with LOAD patients (p < 0.05). Regional mean phase contrast in EOAD patients was higher than in LOAD patients in the superior medial and middle frontal gyrus, anterior and middle cingulate gyrus, postcentral gyrus, superior and inferior parietal gyrus, and precuneus (p ≤ 0.042). These data suggest that EOAD patients have an increased iron accumulation, possibly related to an increased amyloid deposition, in specific cortical regions as compared with LOAD patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Bayesian Modeling of the Dynamics of Phase Modulations and their Application to Auditory Evoked Responses at Different Loudness Scales

    Directory of Open Access Journals (Sweden)

    Zeinab eMortezapouraghdam

    2016-01-01

    Full Text Available We study the effect of long-term habituation signatures of auditory selective attention reflected in the instantaneous phase information of the auditory event-related potentials (ERPs at four distinct stimuli levels of 60dB SPL, 70dB SPL, 80dB SPL and 90dB SPL. The analysis is based on the single-trial level. The effect of habituation can be observed in terms of the changes (jitter in the instantaneous phase information of ERPs. In particular, the absence of habituation is correlated with a consistently high phase synchronization over ERP trials.We estimate the changes in phase concentration over trials using a Bayesian approach, in which the phase is modeled as being drawn from a von Mises distribution with a concentration parameter which varies smoothly over trials. The smoothness assumption reflects the fact that habituation is a gradual process.We differentiate between different stimuli based on the relative changes and absolute values of the estimated concentration parameter using the proposed Bayesian model.

  19. Density-space potential phase difference in a Kelvin--Helmholtz instability

    International Nuclear Information System (INIS)

    Glowienka, J.C.; Jennings, W.C.; Hickok, R.L.

    1974-01-01

    The low-frequency instability found in a hollow cathode discharge in helium was studied using an ion beam probe as a primary diagnostic tool. Three aspects of the instability are discussed: the location and amplitude of the oscillation and its correlation with the shape of the space potential; the phase angle between density and space potential oscillations; and the comparison of the data with three known instability models: Kelvin--Helmholtz, Rayleigh--Taylor, and drift waves--for mode identification. (U.S.)

  20. Early mortality estimates for different nuclear accidents. Final Phase I report, October 1977-April 1979

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, F.F.

    1979-08-01

    Several studies have previously been made of the number of early deaths which might be expected in a population exposed to a cloud of radionuclides which could result from a nuclear accident. These analyses, however, have been limited to one accident scenario or to exposures involving limited numbers of radionuclides. The purpose of this Phase I study was to examine the existing data on the early health effects of inhaled radioactive materials and determined what, if any, new studies were needed to make reasonable estimates of early mortality after exposure of a population to a cloud of radionuclides of any type. The approach used in the Phase I project was to analyze the data bases available on the health effects of inhaled radioactive materials and document those which were adequate and useful. Using these data, a computer based simulation model was developed depicting exposure to a radioactive aerosol, the dose to an individual exposed to the aerosol and the probability of dying from early effects.

  1. Investigation of the effect of different parameters on the phase inversion temperature O/W nanoemulsions

    Directory of Open Access Journals (Sweden)

    D. Kaviani

    2016-01-01

    Full Text Available Objective(s: Nanoemulsions are a kind of emulsions that can be transparent, translucent (size range 50-200 nm or “milky” (up to 500 nm. Nanoemulsions are adequatly effective for transfer of active component through skin which facilitate the entrance of the active component . The transparent nature of the system and lack of the thickener and fluidity are among advantages of nanoemulsion. Materials and Methods: In this study, a nanoemulsion of lemon oil in water was prepared by the phase inversion temperature (PIT emulsification method in which the tween 40 was used as surfactant. The effect of concentration of NaCl in aqueous phase, pH and weight percent of surfactant and aqueous on the PIT and droplet size were investigated. Results: The results showed that with increasing of concentration of NaCl from 0.05 M to 1 M, PIT decrease from 72 to 50. The average droplet sizes, for 0.1, 0.5 and 1 M of NaCl in 25 ºC are 497.3, 308.1 and 189.9 nm, respectively and the polydispersity indexes are 0.348, 0.334 and 0.307, respectively. Conclusion: Considering the characteristics of nanoemulsions such as being transparent, endurance of solution and droplet size can provide suitable reaction environment for polymerization process used in making hygienic and medical materials.

  2. Proteomic Analysis of Bacillus thuringiensis Strain 4.0718 at Different Growth Phases

    Directory of Open Access Journals (Sweden)

    Xiaohui Li

    2012-01-01

    Full Text Available The growth process of Bacillus thuringiensis Bt4.0718 strain was studied using proteomic technologies. The proteins of Bt whole cells at three phases—middle vegetative, early sporulation, and late sporulation—were extracted with lysis buffer, followed with separation by 2-DE and identified by MALDI-TOF/TOF MS. Bioactive factors such as insecticidal crystal proteins (ICPs including Cry1Ac(3, Cry2Aa, and BTRX28, immune inhibitor (InhA, and InhA precursor were identified. InhA started to express at the middle vegetative phase, suggesting its contribution to the survival of Bt in the host body. At the early sporulation phase, ICPs started their expression. CotJC, OppA, ORF1, and SpoIVA related to the formation of crystals and spores were identified, the expression characteristics of which ensured the stable formation of crystals and spores. This study provides an important foundation for further exploration of the stable expression of ICPs, the smooth formation of crystals, and the construction of recombinant strains.

  3. Quantum mechanical systems interacting with different polarizations of gravitational waves in noncommutative phase space

    Science.gov (United States)

    Saha, Anirban; Gangopadhyay, Sunandan; Saha, Swarup

    2018-02-01

    Owing to the extreme smallness of any noncommutative scale that may exist in nature, both in the spatial and momentum sector of the quantum phase space, a credible possibility of their detection lies in the gravitational wave (GW) detection scenario, where one effectively probes the relative length-scale variations ˜O [10-20-10-23] . With this motivation, we have theoretically constructed how a free particle and a harmonic oscillator will respond to linearly and circularly polarized gravitational waves if their quantum mechanical phase space has a noncommutative structure. We critically analyze the formal solutions which show resonance behavior in the responses of both free particle and HO systems to GW with both kind of polarizations. We discuss the possible implications of these solutions in detecting noncommutativity in a GW detection experiment. We use the currently available upper-bound estimates on various noncommutative parameters to anticipate the relative importance of various terms in the solutions. We also argue how the quantum harmonic oscillator system we considered here can be very relevant in the context of the resonant bar detectors of GW which are already operational.

  4. Early mortality estimates for different nuclear accidents. Final Phase I report, October 1977-April 1979

    International Nuclear Information System (INIS)

    Hahn, F.F.

    1979-08-01

    Several studies have previously been made of the number of early deaths which might be expected in a population exposed to a cloud of radionuclides which could result from a nuclear accident. These analyses, however, have been limited to one accident scenario or to exposures involving limited numbers of radionuclides. The purpose of this Phase I study was to examine the existing data on the early health effects of inhaled radioactive materials and determined what, if any, new studies were needed to make reasonable estimates of early mortality after exposure of a population to a cloud of radionuclides of any type. The approach used in the Phase I project was to analyze the data bases available on the health effects of inhaled radioactive materials and document those which were adequate and useful. Using these data, a computer based simulation model was developed depicting exposure to a radioactive aerosol, the dose to an individual exposed to the aerosol and the probability of dying from early effects

  5. A dynamical systems approach for estimating phase interactions between rhythms of different frequencies from experimental data.

    Science.gov (United States)

    Onojima, Takayuki; Goto, Takahiro; Mizuhara, Hiroaki; Aoyagi, Toshio

    2018-01-01

    Synchronization of neural oscillations as a mechanism of brain function is attracting increasing attention. Neural oscillation is a rhythmic neural activity that can be easily observed by noninvasive electroencephalography (EEG). Neural oscillations show the same frequency and cross-frequency synchronization for various cognitive and perceptual functions. However, it is unclear how this neural synchronization is achieved by a dynamical system. If neural oscillations are weakly coupled oscillators, the dynamics of neural synchronization can be described theoretically using a phase oscillator model. We propose an estimation method to identify the phase oscillator model from real data of cross-frequency synchronized activities. The proposed method can estimate the coupling function governing the properties of synchronization. Furthermore, we examine the reliability of the proposed method using time-series data obtained from numerical simulation and an electronic circuit experiment, and show that our method can estimate the coupling function correctly. Finally, we estimate the coupling function between EEG oscillation and the speech sound envelope, and discuss the validity of these results.

  6. Phase Partitioning of GM1 and Its Bodipy-Labeled Analog Determine Their Different Binding to Cholera Toxin

    Directory of Open Access Journals (Sweden)

    Sami Rissanen

    2017-05-01

    Full Text Available Driven by interactions between lipids and proteins, biological membranes display lateral heterogeneity that manifests itself in a mosaic of liquid-ordered (Lo or raft, and liquid-disordered (Ld or non-raft domains with a wide range of different properties and compositions. In giant plasma membrane vesicles and giant unilamellar vesicles, specific binding of Cholera Toxin (CTxB to GM1 glycolipids is a commonly used strategy to label raft domains or Lo membrane environments. However, these studies often use acyl-chain labeled bodipy-GM1 (bdGM1, whose headgroup accessibility and membrane order or phase partitioning may differ from those of GM1, rendering the interpretation of CTxB binding data quite problematic. To unravel the molecular basis of CTxB binding to GM1 and bdGM1, we explored the partitioning and the headgroup presentation of these gangliosides in the Lo and Ld phases using atomistic molecular dynamics simulations complemented by CTxB binding experiments. The conformation of both GM1 and bdGM1 was shown to be largely similar in the Lo and Ld phases. However, bdGM1 showed reduction in receptor availability when reconstituted into synthetic bilayer mixtures, highlighting that membrane phase partitioning of the gangliosides plays a considerable role in CTxB binding. Our results suggest that the CTxB binding is predominately modulated by the partitioning of the receptor to an appropriate membrane phase. Further, given that the Lo and Ld partitioning of bdGM1 differs from those of GM1, usage of bdGM1 for studying GM1 behavior in cells can lead to invalid interpretation of experimental data.

  7. A novel drag force coefficient model for gas–water two-phase flows under different flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Zhi, E-mail: shangzhi@tsinghua.org.cn

    2015-07-15

    Graphical abstract: - Highlights: • A novel drag force coefficient model was established. • This model realized to cover different flow patterns for CFD. • Numerical simulations were performed under wide range flow regimes. • Validations were carried out through comparisons to experiments. - Abstract: A novel drag force coefficient model has been developed to study gas–water two-phase flows. In this drag force coefficient model, the terminal velocities were calculated through the revised drift flux model. The revised drift flux is different from the traditional drift flux model because the natural curve movement of the bubble was revised through considering the centrifugal force. Owing to the revisions, the revised drift flux model was to extend to 3D. Therefore it is suitable for CFD applications. In the revised drift flux model, the different flow patterns of the gas–water two-phase flows were able to be considered. This model innovatively realizes the drag force being able to cover different flow patterns of gas–water two-phase flows on bubbly flow, slug flow, churn flow, annular flow and mist flow. Through the comparisons of the numerical simulations to the experiments in vertical upward and downward pipe flows, this model was validated.

  8. In-phase and out-of-phase gradient-echo imaging in abdominal studies: intra-individual comparison of three different techniques

    International Nuclear Information System (INIS)

    Ramalho, Miguel; Heredia, Vasco; Campos, Rafael O. P. de; Azevedo, Rafael M.; Semelka, Richard C.; Dale, Brian M.

    2012-01-01

    Background: T1-weighted gradient-echo in-phase and out-of-phase imaging is an essential component of comprehensive abdominal MR exams. It is useful for the study of fat-containing lesions and to identify various disease states related to the presence of fat in the liver. Purpose: To compare three T1-weighted in-phase and out-of-phase (IP/OP) gradient-echo imaging sequences in an intra-individual fashion, and to determine whether advantages exist for each of these sequences for various patient types. Material and Methods: One hundred and eighteen consecutive subjects (74 men, 44 women; mean age 53.9 ± 13.8 years) who had MRI examinations containing all three different IP/OP sequences (two-dimensional spoiled gradient-echo [2D-GRE], three-dimensional gradient-echo [3D-GRE], and magnetization-prepared gradient-recall echo [MP-GRE]) were included. Two different reviewers independently and blindly qualitatively evaluated IP/OP sequences to determine image quality, extent of artifacts, lesion detectability and conspicuity, and subjective grading of liver steatosis for the various sequences. Quantitative analysis was also performed. Qualitative and quantitative data were subjected to statistical analysis. Results: Respiratory ghosting, parallel imaging, and truncation artifacts as well as shading and blurring were more pronounced with 3D-GRE IP/OP imaging. Overall image quality was higher with 2D-GRE (P < 0.05). Detectability of low-fluid content lesions was lower with IP/OP MP-GRE sequences. MP-GRE sequences had the lowest SNRs (P < 0.001). Liver-to-spleen and liver-to-lesion CNRs were significantly lower with 3D-GRE and MP-GR, respectively (P < 0.001). Fat liver indexes showed strongly positive correlation between all sequences. Conclusion: Currently, 2D-GRE remains the best approach for clinical IP/OP imaging. The good image quality of MP-GRE sequences acquired in a free-breathing manner should recommend its use in patients unable to suspend breathing

  9. In-phase and out-of-phase gradient-echo imaging in abdominal studies: intra-individual comparison of three different techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ramalho, Miguel; Heredia, Vasco; Campos, Rafael O. P. de; Azevedo, Rafael M.; Semelka, Richard C. (Dept. of Radiology, Univ. of North Carolina at Chapel Hill (United States)); Dale, Brian M. (Siemens Medical Systems, Morrisville (United States)), email: richsem@med.unc.edu

    2012-05-15

    Background: T1-weighted gradient-echo in-phase and out-of-phase imaging is an essential component of comprehensive abdominal MR exams. It is useful for the study of fat-containing lesions and to identify various disease states related to the presence of fat in the liver. Purpose: To compare three T1-weighted in-phase and out-of-phase (IP/OP) gradient-echo imaging sequences in an intra-individual fashion, and to determine whether advantages exist for each of these sequences for various patient types. Material and Methods: One hundred and eighteen consecutive subjects (74 men, 44 women; mean age 53.9 +- 13.8 years) who had MRI examinations containing all three different IP/OP sequences (two-dimensional spoiled gradient-echo [2D-GRE], three-dimensional gradient-echo [3D-GRE], and magnetization-prepared gradient-recall echo [MP-GRE]) were included. Two different reviewers independently and blindly qualitatively evaluated IP/OP sequences to determine image quality, extent of artifacts, lesion detectability and conspicuity, and subjective grading of liver steatosis for the various sequences. Quantitative analysis was also performed. Qualitative and quantitative data were subjected to statistical analysis. Results: Respiratory ghosting, parallel imaging, and truncation artifacts as well as shading and blurring were more pronounced with 3D-GRE IP/OP imaging. Overall image quality was higher with 2D-GRE (P < 0.05). Detectability of low-fluid content lesions was lower with IP/OP MP-GRE sequences. MP-GRE sequences had the lowest SNRs (P < 0.001). Liver-to-spleen and liver-to-lesion CNRs were significantly lower with 3D-GRE and MP-GR, respectively (P < 0.001). Fat liver indexes showed strongly positive correlation between all sequences. Conclusion: Currently, 2D-GRE remains the best approach for clinical IP/OP imaging. The good image quality of MP-GRE sequences acquired in a free-breathing manner should recommend its use in patients unable to suspend breathing

  10. Phase-contrast computed tomography for quantification of structural changes in lungs of asthma mouse models of different severity

    International Nuclear Information System (INIS)

    Dullin, Christian; Larsson, Emanuel; Tromba, Giuliana; Markus, Andrea M.; Alves, Frauke

    2015-01-01

    Synchrotron inline phase-contrast computed tomography in combination with single-distance phase retrieval enables quantification of morphological alterations in lungs of mice with mild and severe experimental allergic airways disease in comparison with healthy controls. Lung imaging in mouse disease models is crucial for the assessment of the severity of airway disease but remains challenging due to the small size and the high porosity of the organ. Synchrotron inline free-propagation phase-contrast computed tomography (CT) with its intrinsic high soft-tissue contrast provides the necessary sensitivity and spatial resolution to analyse the mouse lung structure in great detail. Here, this technique has been applied in combination with single-distance phase retrieval to quantify alterations of the lung structure in experimental asthma mouse models of different severity. In order to mimic an in vivo situation as close as possible, the lungs were inflated with air at a constant physiological pressure. Entire mice were embedded in agarose gel and imaged using inline free-propagation phase-contrast CT at the SYRMEP beamline (Synchrotron Light Source, ‘Elettra’, Trieste, Italy). The quantification of the obtained phase-contrast CT data sets revealed an increasing lung soft-tissue content in mice correlating with the degree of the severity of experimental allergic airways disease. In this way, it was possible to successfully discriminate between healthy controls and mice with either mild or severe allergic airway disease. It is believed that this approach may have the potential to evaluate the efficacy of novel therapeutic strategies that target airway remodelling processes in asthma

  11. Phase-contrast computed tomography for quantification of structural changes in lungs of asthma mouse models of different severity

    Energy Technology Data Exchange (ETDEWEB)

    Dullin, Christian, E-mail: christian.dullin@med.uni-goettingen.de [University Medical Center Goettingen, Robert Koch Strasse 40, Goettingen, Lower Saxony 37075 (Germany); Larsson, Emanuel [Elettra-Sincrotrone Trieste, Strada Statale 14, km 163,5 in AREA Science Park, Basovizza (Trieste) 34149 (Italy); University of Trieste, Trieste (Italy); Linkoeping University, SE-581 83 Linkoeping (Sweden); Tromba, Giuliana [Elettra-Sincrotrone Trieste, Strada Statale 14, km 163,5 in AREA Science Park, Basovizza (Trieste) 34149 (Italy); Markus, Andrea M. [University Medical Center Goettingen, Robert Koch Strasse 40, Goettingen, Lower Saxony 37075 (Germany); Alves, Frauke [University Medical Center Goettingen, Robert Koch Strasse 40, Goettingen, Lower Saxony 37075 (Germany); University Medical Center Goettingen, Robert Koch Strasse 40, Goettingen, Lower Saxony 37075 (Germany); Max Planck Institut for Experimental Medicine, Hermann-Rein-Strasse 3, Goettingen, Lower Saxony 37075 (Germany)

    2015-06-17

    Synchrotron inline phase-contrast computed tomography in combination with single-distance phase retrieval enables quantification of morphological alterations in lungs of mice with mild and severe experimental allergic airways disease in comparison with healthy controls. Lung imaging in mouse disease models is crucial for the assessment of the severity of airway disease but remains challenging due to the small size and the high porosity of the organ. Synchrotron inline free-propagation phase-contrast computed tomography (CT) with its intrinsic high soft-tissue contrast provides the necessary sensitivity and spatial resolution to analyse the mouse lung structure in great detail. Here, this technique has been applied in combination with single-distance phase retrieval to quantify alterations of the lung structure in experimental asthma mouse models of different severity. In order to mimic an in vivo situation as close as possible, the lungs were inflated with air at a constant physiological pressure. Entire mice were embedded in agarose gel and imaged using inline free-propagation phase-contrast CT at the SYRMEP beamline (Synchrotron Light Source, ‘Elettra’, Trieste, Italy). The quantification of the obtained phase-contrast CT data sets revealed an increasing lung soft-tissue content in mice correlating with the degree of the severity of experimental allergic airways disease. In this way, it was possible to successfully discriminate between healthy controls and mice with either mild or severe allergic airway disease. It is believed that this approach may have the potential to evaluate the efficacy of novel therapeutic strategies that target airway remodelling processes in asthma.

  12. Phase relation of LaFe11· 6Si1· 4 compounds annealed at different ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 35; Issue 2. Phase relation of LaFe11.6Si1.4 compounds annealed at different high-temperature and the magnetic property of LaFe11.6−CoSi1.4 compounds. Xiang Chen Yungui Chen Yongbai Tang. Volume 35 Issue 2 April 2012 pp 175-182 ...

  13. [Study of the phase transformation of TiO2 with in-situ XRD in different gas].

    Science.gov (United States)

    Ma, Li-Jing; Guo, Lie-Jin

    2011-04-01

    TiO2 sample was prepared by sol-gel method from chloride titanium. The phase transformation of the prepared TiO2 sample was studied by in-situ XRD and normal XRD in different gas. The experimental results showed that the phase transformation temperatures of TiO2 were different under in-situ or normal XRD in different kinds of gas. The transformation of amorphous TiO2 to anatase was controlled by kinetics before 500 degrees C. In-situ XRD showed that the growth of anatase was inhibited, but the transformation of anatase to rutile was accelerated under inactive nitrogen in contrast to air. Also better crystal was obtained under hydrogen than in argon. These all showed that external oxygen might accelerate the growth of TiO2, but reduced gas might partly counteract the negative influence of lack of external oxygen. The mechanism of phase transformation of TiO2 was studied by in-situ XRD in order to control the structure in situ.

  14. Selectivity of calixarene-bonded silica phases in HPLC: Description of special characteristics with a multiple term linear equation at different methanol concentrations.

    Science.gov (United States)

    Schneider, Christian; Jira, Thomas

    2010-10-01

    Retention and selectivity characteristics of different calixarene-, resorcinarene- and alkyl-bonded stationary phases are examined by analyzing a set of test solutes covering the main interactions (hydrophobic, steric, ionic, polar) that apply in HPLC. Therefore Dolan and Snyder's multiple term linear equation has been adapted to fit the properties of calixarene-bonded columns. The obtained parameters are used to describe retention and selectivity of the novel Caltrex(®) phases and to elucidate underlying mechanisms of retention. Here, differences of stationary phase characteristics at different methanol concentrations in the mobile phases are examined. Both selectivity and retention were found to depend on the methanol content. Differences of these dependencies were found for different stationary phases and interactions. The differences between common alkyl-bonded and novel calixarene-bonded phases increase with increasing methanol content.

  15. Trace metals partitioning among different sedimentary mineral phases and the deposit-feeding polychaete Armandia brevis

    International Nuclear Information System (INIS)

    Díaz-de-Alba, Margarita; Huerta-Diaz, Miguel Angel; Delgadillo-Hinojosa, Francisco; Hare, Landis; Galindo-Riaño, M. Dolores; Siqueiros-Valencia, Arturo

    2016-01-01

    Trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were determined in two operationally defined fractions (HCl and pyrite) in sediments from Ensenada and El Sauzal harbors (Mexico). The HCl fraction had significantly higher metal concentrations relative to the pyrite fraction in both harbors, underlining the weak tendency of most trace metals to associate with pyrite. Exceptionally, Cu was highly pyritized, with degrees of trace metal pyritization (DTMP) > 80% in both harbors. Dissolved Fe flux measurements combined with solid phase Fe sulfide data indicated that 98 mt of Fe are precipitated as iron sulfides every year in Ensenada Harbor. These Fe sulfides (and associated trace metals) will remain preserved in the sediments, unless they are perturbed by dredging or sediment resuspension. Calculations indicate that dredging activities could export to the open ocean 0.20 ± 0.13 to (0.30 ± 0.56) × 10"3 mt of Cd and Cu, respectively, creating a potential threat to marine benthic organisms. Degrees of pyritization (DOP) values in Ensenada and El Sauzal harbors were relatively low (< 25%) while degrees of sulfidization (DOS) were high (~ 50%) because of the contribution of acid volatile sulfide. DOP values correlated with DTMP values (p ≤ 0.001), indicating that metals are gradually incorporated into pyrite as this mineral is formed. Significant correlations were also found between DTMP values and − log(K_s_p_(_M_e_S_)/K_s_p_(_p_y_r_)) for both harbors, indicating that incorporation of trace metals into the pyrite phase is a function of the solubility product of the corresponding metal sulfide. The order in which elements were pyritized in both harbors was Zn ≈ Mn < Fe < Cd ≈ Pb < Ni ≈ Co < < Cu. Lastly, a strong correlation (r"2 = 0.87, p < 0.01) was found between average reactive trace metal concentrations and metal concentrations measured in Armandia brevis (a deposit-feeding Opheliid polychaete), suggesting that these labile sedimentary metals are

  16. Trace metals partitioning among different sedimentary mineral phases and the deposit-feeding polychaete Armandia brevis

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-de-Alba, Margarita [Department of Analytical Chemistry, Institute of Biomolecules (INBIO), Faculty of Sciences, CEI-MAR, University of Cadiz, Campus Rio S. Pedro, E-11510, Puerto Real, Cadiz (Spain); Huerta-Diaz, Miguel Angel, E-mail: huertam@uabc.edu.mx [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California (Mexico); Delgadillo-Hinojosa, Francisco [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California (Mexico); Hare, Landis [Centre Eau Terre Environnement, 490, rue de la Couronne, Québec, Québec G1K 9A9 (Canada); Galindo-Riaño, M. Dolores [Department of Analytical Chemistry, Institute of Biomolecules (INBIO), Faculty of Sciences, CEI-MAR, University of Cadiz, Campus Rio S. Pedro, E-11510, Puerto Real, Cadiz (Spain); Siqueiros-Valencia, Arturo [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California (Mexico)

    2016-02-01

    Trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were determined in two operationally defined fractions (HCl and pyrite) in sediments from Ensenada and El Sauzal harbors (Mexico). The HCl fraction had significantly higher metal concentrations relative to the pyrite fraction in both harbors, underlining the weak tendency of most trace metals to associate with pyrite. Exceptionally, Cu was highly pyritized, with degrees of trace metal pyritization (DTMP) > 80% in both harbors. Dissolved Fe flux measurements combined with solid phase Fe sulfide data indicated that 98 mt of Fe are precipitated as iron sulfides every year in Ensenada Harbor. These Fe sulfides (and associated trace metals) will remain preserved in the sediments, unless they are perturbed by dredging or sediment resuspension. Calculations indicate that dredging activities could export to the open ocean 0.20 ± 0.13 to (0.30 ± 0.56) × 10{sup 3} mt of Cd and Cu, respectively, creating a potential threat to marine benthic organisms. Degrees of pyritization (DOP) values in Ensenada and El Sauzal harbors were relatively low (< 25%) while degrees of sulfidization (DOS) were high (~ 50%) because of the contribution of acid volatile sulfide. DOP values correlated with DTMP values (p ≤ 0.001), indicating that metals are gradually incorporated into pyrite as this mineral is formed. Significant correlations were also found between DTMP values and − log(K{sub sp(MeS)}/K{sub sp(pyr)}) for both harbors, indicating that incorporation of trace metals into the pyrite phase is a function of the solubility product of the corresponding metal sulfide. The order in which elements were pyritized in both harbors was Zn ≈ Mn < Fe < Cd ≈ Pb < Ni ≈ Co < < Cu. Lastly, a strong correlation (r{sup 2} = 0.87, p < 0.01) was found between average reactive trace metal concentrations and metal concentrations measured in Armandia brevis (a deposit-feeding Opheliid polychaete), suggesting that these labile sedimentary metals are

  17. Comment on "An Analysis of VLF Electric Field Spectra Measured in Titan's Atmosphere by The Huygens Probe" By J. A. Morente et al.

    Science.gov (United States)

    Grard, Rejean; Berthelin, Stephanie; Beghin, Christian; Hamelin, Michel; Berthelier, Jean-Jacques; Lopez-Moreno, Jose J.; Simoes, Fernando

    2011-01-01

    Morente et al. have recently revisited the VLF electric field measurements made with the Permittivity, Wave and Altimetry (PWA) instrument during the descent of the Huygens Probe through the atmosphere of Titan. They assert that they have identified several harmonics of the transverse resonance mode of the surface?]ionosphere cavity, which would prove the existence of an electrical activity in the atmosphere of the largest satellite of Saturn. We refute this finding on the basis that it results from an artifact due to an improper analysis of the data set. [2] The investigators of the Permittivity, Wave and Altimetry (PWA) experiment on the Huygens Probe have reported the extremely low frequency (ELF) and very low frequency (VLF) electric signals recorded during the descent through the atmosphere of Titan. The PWA data are archived in the Planetary Science Archive (PSA) of ESA, and an extensive description of the instrument is at the disposal of the scientific community. Morente and his coworkers have revisited this data set and reported the results of their investigations in two papers. In a first paper, they claim that they have detected in the ELF range (0.100 Hz) several harmonics of a global resonance allegedly generated by lightning activity in the spherical cavity guide formed by the surface of Titan and the inner boundary of the ionosphere, a phenomenon similar to the Schumann resonance observed at EartH In the second paper dedicated to the VLF electric signal recorded by PWA, in the range 0.10 kHz, they argue that they can also bring out the transverse resonance and its harmonics, a more local phenomenon that develops around the excitation source and whose frequency is controlled by the separation between Titan?fs surface and the inner ionospheric boundary. [3] The PWA investigators have analyzed the narrowband ELF signal at about 36 Hz effectively observed during the entire descent. They have not endorsed, however, the alternative approach of Morente et al

  18. Liquid phase radioimmunoassay system for determination of progesterone in human serum using different radiolabeled tracers

    International Nuclear Information System (INIS)

    Mehany, N.L.; El-Kolaly, M.T.; Sallam, Kh.M.; EI-Hashash, M.A.

    2007-01-01

    The preparation and development of primary reagents of progesterone radioimmunoassay (R1A) technique with low cost is considered to be the main objective of the present study . The preparation of 125 l-progesterone radiotracers was carried out using chloramine-T, iodogen and lactoperoxidase oxidation methods and they were purified using high perfomance liquid chromatography (HPLC). Tyramine hydrochloride was conjugated with activated progesterone 11α-hemisuccinate and then iodinated using Na 125 I.The tracers obtained were investigated in terms of radiochemical purity, radiochemical yield and immunoreactivity. The production of polyclonal antibodies was undertaken by immunizing six New-Zealand rabbits subcutaneously through primary injection and four booster doses.The preparation of progesterone standards were carried out by preparing stock standard solution of progesterone in ethanol. After evaporation of ethanol, the steroid assay buffer was used as a standard matrix to prepare the working standards required. Optimization and validation of the assay were carried out. The results obtained provide a highly sensitive, specific and accurate RIA system of progesterone based on liquid phase separation. In conclusion, this assay could be used in evaluating corpus luteum insufficiency among women in child bearing period

  19. Three modified activated carbons by different ligands for the solid phase extraction of copper and lead

    International Nuclear Information System (INIS)

    Ghaedi, M.; Ahmadi, F.; Tavakoli, Z.; Montazerozohori, M.; Khanmohammadi, A.; Soylak, M.

    2008-01-01

    In the presented work, 5,5-diphenylimidazolidine-2,4-dione (phenytoin) (DFTD), 5,5-diphenylimidazolidine-2-thione-,4-one (thiophenytoin) (DFID) and 2-(4'-methoxy-benzylidenimine) thiophenole (MBIP) modified activated carbons have been used for the solid phase extraction of copper and lead ions prior to their flame atomic absorption spectrometric determinations. The influences of the various analytical parameters including pH, amounts of reagent, sample volume and eluent type, etc. on the recovery efficiencies of copper and lead ions were investigated. The influences of alkaline, earth alkaline and some transition metals on the adsorption of the analytes were also examined. The detection limits by three sigma for analyte ions were 0.65 and 0.42 μg L -1 using activated carbon modified with DFID; 0.52 and 0.37 μg L -1 using activated carbon modified with DFTD and 0.46 and 0.31 μg L -1 using activated carbon modified with MBIP for Pb(II) and Cu(II), respectively. The procedure was applied to the determination of analytes in natural waters, soil, and blood samples with satisfactory results (recoveries greater than 95%, R.S.D.'s lower than 4%)

  20. Three modified activated carbons by different ligands for the solid phase extraction of copper and lead

    Energy Technology Data Exchange (ETDEWEB)

    Ghaedi, M. [Chemistry Department, University of Yasouj, Yasouj 75914-353 (Iran, Islamic Republic of)], E-mail: m_ghaedi@mail.yu.ac.ir; Ahmadi, F.; Tavakoli, Z. [Gachsaran Azad University, Gachsaran (Iran, Islamic Republic of); Montazerozohori, M. [Chemistry Department, University of Yasouj, Yasouj 75914-353 (Iran, Islamic Republic of); Khanmohammadi, A. [Young Researchers Club, Gachsaran Azad University, Gachsaran (Iran, Islamic Republic of); Soylak, M. [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

    2008-04-15

    In the presented work, 5,5-diphenylimidazolidine-2,4-dione (phenytoin) (DFTD), 5,5-diphenylimidazolidine-2-thione-,4-one (thiophenytoin) (DFID) and 2-(4'-methoxy-benzylidenimine) thiophenole (MBIP) modified activated carbons have been used for the solid phase extraction of copper and lead ions prior to their flame atomic absorption spectrometric determinations. The influences of the various analytical parameters including pH, amounts of reagent, sample volume and eluent type, etc. on the recovery efficiencies of copper and lead ions were investigated. The influences of alkaline, earth alkaline and some transition metals on the adsorption of the analytes were also examined. The detection limits by three sigma for analyte ions were 0.65 and 0.42 {mu}g L{sup -1} using activated carbon modified with DFID; 0.52 and 0.37 {mu}g L{sup -1} using activated carbon modified with DFTD and 0.46 and 0.31 {mu}g L{sup -1} using activated carbon modified with MBIP for Pb(II) and Cu(II), respectively. The procedure was applied to the determination of analytes in natural waters, soil, and blood samples with satisfactory results (recoveries greater than 95%, R.S.D.'s lower than 4%)

  1. Comparison of the N+2 photochemistry at different phases of the solar cycle

    International Nuclear Information System (INIS)

    Torr, M.R.; Torr, D.G.; Ong, R.A.

    1980-01-01

    Over the increasing phase of solar activity from 1974 to 1978 the F/sub 10.7/ index increased from approx.70 to approx.180. Earlier studies of the N + 2 ion based on the Atmosphere Explorer satellite measurements used data gathereed in 1974. A study of N + 2 using 1978 measurements made during significantly higher solar EUV fluxes reveals a change in the relative importance of the major chemical processes. Photoionization of N 2 is found to be the major source of N + 2 in the F 2 layer, by contrast with the charge exchange reaction of O + ( 2 D) with N 2 , which was dominant for the lower solar activity. The increased electron concentrations enhance the importance of reactions involving electrons, thus permitting good determinations of the relevant reaction rate coefficients, which could not be done in the earlier studies. As such, the 1978 data provide a useful opportunity to confirm the photochemical scheme established earlier and to improve the accuracy of the determination of the rate coefficients for certain processes. Specifically, we determine the rate coefficients for dissociative recombination of N + 2 with electrons, confirming laboratory measurements; we refine an earlier determination of the charge exchange rate coefficient for O + ( 2 D) with N 2 to (7 +- 3) x 10 -11 cm 3 s -1 ; and we determine the rate coefficient for quenching of O + ( 2 D) by electrons, confirming a theoretical calculation

  2. First principles study of structural and electronic properties of different phases of boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Rashid [Centre for High Energy Physics, University of the Punjab, Lahore 54590 (Pakistan)], E-mail: rasofi@hotmail.com; Fazal-e-Aleem [Centre for High Energy Physics, University of the Punjab, Lahore 54590 (Pakistan); Hashemifar, S. Javad; Akbarzadeh, Hadi [Department of Physics, Isfahan University of Technology, 84156 Isfahan (Iran, Islamic Republic of)

    2007-11-15

    A theoretical study of structural and electronic properties of the four phases of BN (zincblende, wurtzite, hexagonal and rhombohedral) is presented. The calculations are done by full potential (linear) augmented plane wave plus local orbitals (APW+lo) method based on the density functional theory (DFT) as employed in WIEN2k code. Using the local density approximation (LDA) and generalized gradient approximation (GGA-PBE) for the exchange correlation energy functional, we have calculated lattice parameters, bulk modulus, its pressure derivative and cohesive energy. In order to calculate electronic band structure, another form of the generalized gradient approximation proposed by Engel and Vosko (GGA-EV) has been employed along with LDA and GGA-PBE. It is found that all the three approximations exhibit similar band structure qualitatively. However, GGA-EV gives energy band gap values closer to the measured data. Our results for structural and electronic properties are compared with the experimental and other theoretical results wherever these are available.

  3. Effects of gamma irradiation on different phases of coffee borer Hypothenemus hampei (Ferrari, 1867)

    International Nuclear Information System (INIS)

    Wiendl, F.M.; Silva, A.L. da.

    1974-10-01

    Two experiments carried out in order to determine immediate lethal doses (LD sub(I)) for gamma irradiation of larvae, pupae and adults hypothenemus hampei (Ferrari, 1867) are presented. One experiment aimed only the determination of LD sub(I) for the adults of the coffee borer-outside the coffee-berries. The other to obtain the equivalent data for insects inside the coffee-berry, for all phases of the development cycle of the insect. It was found that LD sub(I) for larvae was around 350 Krad and for pupae around 400 Krad. For the adults, the LD sub(I) for insects outside the coffee-berry was 475 Krad and 525 for insects inside the coffee-berry. It was found that smaller doses caused a pronunced decrease in the insect lifetime, lifetime decrease proportionally as the irradiation dose increase. According to the results obtained, is postulated that this species of coffee-borer may be considered resistant to gamma radiation [pt

  4. A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar

    Science.gov (United States)

    Hyun, Eugin; Jin, Young-Seok; Lee, Jong-Hun

    2016-01-01

    For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW) radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT) is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method. PMID:26805835

  5. A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar

    Directory of Open Access Journals (Sweden)

    Eugin Hyun

    2016-01-01

    Full Text Available For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method.

  6. S-phase cell distribution in the small intestine irradiated at different times of the day. I. Acute irradiation injury

    Energy Technology Data Exchange (ETDEWEB)

    Becciolini, A; Balzi, M; Cremonini, D; Fabbrica, D [Florence Univ. (Italy). Ist. di Radiologia

    1983-01-01

    The S-phase cell distribution has been analysed to evaluate the behaviour of proliferative cells in the intestinal epithelium after irradiation at different times of the day. A marked reduction of S cell frequency was observed at early intervals after abdominal irradiation; this reduction was particularly evident in the lower half of the crypts. At subsequent intervals a progressive extension of the proliferative compartment, with labelled cells also at the top of the crypt, was present. The irradiated groups generally showed a homogeneous behaviour even if a more marked reduction in S-phase cells was observed in group C. The invertase activity, a brush border enzyme synthetized during the differentiation process, presented a different behaviour at the early intervals in the irradiated groups. When the extension of the proliferative compartment occurred the invertase activity reached values close to zero. The modifications in brush border enzymes and in S-phase cell distribution, at early killing times, led to the hypothesis of an early differentiation.

  7. Phase-contrast X-ray CT imaging of the kidney. Differences between ethanol fixation and formalin fixation

    International Nuclear Information System (INIS)

    Shirai, Ryota; Kunii, Takuya; Maruyama, Hiroko; Takeda, Tohoru; Yoneyama, Akio; Lwin, Thet Thet

    2012-01-01

    A phase-contrast X-ray imaging technique using an X-ray interferometer that provides approximately 1000 times higher sensitivity than the conventional X-ray imaging method for low-atomic number elements based on the difference in the mass attenuation coefficient has recently been developed. In the present study, we compared rat kidneys fixed in 100% ethanol and in 10% formalin to evaluate the effects of ethanol in enhancing image contrast in phase-contrast imaging because ethanol causes significant dehydration of tissues and enhances density differences between tissue components. The experiments were conducted at the Photon Factory in Tsukuba, and the X-ray energy was set at 35 keV. Fine anatomical structures in the kidney such as the glomeruli, tubules, and vessels were observed. Particularly clear renal images were obtained with ethanol fixation. The pixel value ratio between the cortex and medulla was about 43% in ethanol-fixed kidneys and 21% in formalin-fixed kidneys. In other words, the contrast in ethanol-fixed kidneys was about two times higher than that in formalin-fixed kidneys. Histological examination showed significantly condensed features in the cortex. The results of this study suggest that the ethanol fixation technique may be useful for enhancing the image contrast of renal structures in the phase-contrast X-ray imaging technique. (author)

  8. SOME SERUM BIOCHEMICAL CONSTITUENTS OF MARES DURING DIFFERENT PHASES OF REPRODUCTIVE CYCLE

    Directory of Open Access Journals (Sweden)

    F. Ali, L. A. Lodhi, Z. I. Qureshi, H. A. Samad and R. U. Shahid1.

    2004-07-01

    Full Text Available Serum glucose, total proteins, calcium and inorganic phosphorus were determined in estrual, pregnant, infertile and regular breeder mares, each group comprising of 10 animals. The mares were grouped on the basis of rectal examination, history and records. There was a significant (P0.05 difference in the serum phosphorus levels among all the groups of mares.

  9. A comparison of three different pension savings products with special emphasis on the payout phase

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte; Linnemann, Per

    2012-01-01

    The purpose of this article is to illustrate how the pension benefits a pension saver will (expect to) receive will depend on the type of pension scheme chosen. We compare three widely different pension savings products: the ‘‘traditional’’ with-profits scheme involving bonus entitlement (average...

  10. Study on two phase flow characteristics in annular pulsed extraction column with different ratio of annular width to column diameter

    International Nuclear Information System (INIS)

    Qin Wei; Dai Youyuan; Wang Jiading

    1994-01-01

    Annular pulsed extraction column can successfully provide large throughput and can be made critically safe for fuel reprocessing. This investigation is to study the two phase flow characteristics in annular pulsed extraction column with four different annular width. 30% TBP (in kerosene)-water is used (water as continuous phase). Results show that modified Pratt correlation is valid under the experimental operation conditions for the annular pulsed extraction column. The characteristic velocity U K decreased with the increase of energy input and increased with the increase of the ratio of annular width to column diameter. Flooding velocity correlation is suggested. The deviation of the calculated values from the experimental data is within +20% for four annular width in a pulsed extraction column

  11. Extraction of seawater-derived neodymium from different phases of deep sea sediments by selective leaching

    Science.gov (United States)

    Blaser, P.; Lippold, J. A.; Frank, N.; Gutjahr, M.; Böhm, E.

    2014-12-01

    In order to deduce reliable information about the interaction of the oceans with the climate system as a whole in the past, the reconstruction of water mass circulation is crucial. The analysis of seawater-derived neodymium isotopes (143Nd/144Nd, expressed as ɛNd) in marine sediments provides a unique proxy for deep water provenance in particular in the Atlantic [1]. The ɛNd signature and thus the mixing proportion of the local bottom water masses is archived in authigenic phases in the sediment. Obtaining seawater ɛNd from authigenic accretions bound to foraminiferal tests has lately become the preferred since most reliable method [2]. Attempts have also been made to extract the Nd-rich authigenic metal fraction by leaching it off the bulk sediment and thereby use this proxy with less effort, in the highest possible resolution and in sediments where foraminifera are not sufficiently present. However, often other sedimentary components are also leached in the process and contaminate the extracted Nd [3,4]. In this project several core-top and older sediments across the Atlantic have been leached in ten consecutive steps with either dilute buffered acetic acid or an acid-reductive solution. The leachates were analysed on their elemental and Nd isotope compositions, as well as rare earth element (REE) distributions. By graduating the total leaching procedure into smaller stages the results display which processes take place in the course of sediment leaching in the laboratory and which components of the sediment are most reactive. Thus, they help to better evaluate the quality of sediment leaches for ɛNd analysis. Clearly, organic calcite acts as a fast reacting buffer and at the point where its amount is sufficiently reduced the leaching of other components commences and the Nd concentration peaks. Corruption of the extracted ɛNd signal by non-authigenic sources in many cases occured early in the leaching sequence, indicating that only very cautious leaching

  12. Household costs of illness during different phases of tuberculosis treatment in Central Asia: a patient survey in Tajikistan

    Directory of Open Access Journals (Sweden)

    Abdualimova Hanifa

    2010-01-01

    Full Text Available Abstract Background Illness-related costs incurred by patients constitute a severe economic burden for households especially in low-income countries. High household costs of illness lead to impoverishment; they impair affordability and equitable access to health care and consequently hamper tuberculosis (TB control. So far, no study has investigated patient costs of TB in the former Soviet Union. Methods All adult new pulmonary TB cases enrolled into the DOTS program in 12 study districts during the study period were enrolled. Medical and non-medical expenditure as well as loss of income were quantified in two interviews covering separate time periods. Costs of different items were summed up to calculate total costs. For missing values, multiple imputation was applied. Results A cohort of 204 patients under DOTS, 114 men and 90 women, participated in the questionnaire survey. Total illness costs of a TB episode averaged $1053 (c. $4900 purchasing power parity, PPP, of which $292, $338 and $422 were encountered before the start of treatment, during intensive phase and in continuation phase, respectively. Costs per month were highest before the start of treatment ($145 and during intensive phase ($153 and lower during continuation phase ($95. These differences were highly significant (paired t-test, p Conclusions The illness-related costs of an episode of TB exceed the per capita GDP of $1600 PPP about two-and-a-half times. Hence, these costs are catastrophic for concerned households and suggest a high risk for impoverishment. Costs are not equally spread over time, but peak in early stages of treatment, exacerbating the problem of affordability. Mitigation strategies are needed in order to control TB in Tajikistan and may include social support to the patients as well as changes in the management of TB cases. These mitigation strategies should be timed early in treatment when the cost burden is highest.

  13. Effect of liquid density differences on boiling two-phase flow stability

    International Nuclear Information System (INIS)

    Furuya, Masahiro; Manera, Annalisa; Bragt, David D.B.; Hagen, Tim H.J.J. van der; Kruijf, Willy J.M.de

    2002-01-01

    In order to investigate the effect of considering liquid density dependence on local fluid temperature in the thermal-hydraulic stability, a linear stability analysis is performed for a boiling natural circulation loop with an adiabatic riser. Type-I and Type-II instabilities were to investigate according to Fukuda-Kobori's classification. Type-I instability is dominant when the flow quality is low, while Type-II instability is relevant at high flow quality. Type-II instability is well known as the typical density wave oscillation. Neglecting liquid density differences yields estimates of Type-II instability margins that are too small, due to both a change in system-dynamics features and in the operational point. On the other hand, neglecting liquid density differences yields estimates of Type-I stability margins that are too large, especially due to a change in the operational point. Neglecting density differences is thus non-conservative in this case. Therefore, it is highly recommended to include liquid density dependence on the fluid subcooling in the stability analysis if a flow loop with an adiabatic rise is operated under the condition of low flow quality. (author)

  14. Evaluating the normal individual cardiac function in different imaging phases post exercise and rest by gated SPECT myocardial perfusion

    International Nuclear Information System (INIS)

    Hua, W.; Li, S.J.; Liu, J.Z.; Li, X.F.; Jin, C.R.; Hu, G.; Wang, J.

    2007-01-01

    Full text: Objectives: To evaluate the normal individual cardiac function in the different imaging phases post-exercise and rest by GSPECT. Methods: 46 normal individuals underwent exercise/rest GSPECT using 99mTc-MIBI by 2- day program. Sequential imaging was started 15, 35 and 120 minutes after exercise and rest imaging was performed the following day. The left ventricular EF and EDV, ESV values were calculated with the Cedars-Sinai program. Results: The EF values of post- exercise at 15, 35, and 120m was 64.48±7.43%, 65.02±7.66%, and 60.98±7.28% respectively, and the rest EF value was 61.46±7.23%. The post exercise EF at 15m and 35m was higher than EF at post- exercise 120m and rest, but there is a significant difference only between post exercise 35m and rest (P< 0.05), and all post exercise EF did not increase at least 5% from EF at-rest. The EDV and ESV values did not have statistically significant differences at 15, 35,120m post-exercise and rest. The heart rate at 15,35m post- exercise was higher significantly than at rest. Conclusions: The different imaging phases after exercise with 99mTc-MIBI GSPECT affects LVEF in normal individuals, the 35m post- exercise EF is highest. (author)

  15. Positional differences in reactive hyperemia provide insight into initial phase of exercise hyperemia.

    Science.gov (United States)

    Jasperse, Jeffrey L; Shoemaker, J Kevin; Gray, Eric J; Clifford, Philip S

    2015-09-01

    Studies have reported a greater blood flow response to muscle contractions when the limb is below the heart compared with above the heart, and these results have been interpreted as evidence for a skeletal muscle pump contribution to exercise hyperemia. If limb position affects the blood flow response to other vascular challenges such as reactive hyperemia, this interpretation may not be correct. We hypothesized that the magnitude of reactive hyperemia would be greater with the limb below the heart. Brachial artery blood flow (Doppler ultrasound) and blood pressure (finger-cuff plethysmography) were measured in 10 healthy volunteers. Subjects lay supine with one arm supported in two different positions: above or below the heart. Reactive hyperemia was produced by occlusion of arterial inflow for varying durations: 0.5 min, 1 min, 2 min, or 5 min in randomized order. Peak increases in blood flow were 77 ± 11, 178 ± 24, 291 ± 25, and 398 ± 33 ml/min above the heart and 96 ± 19, 279 ± 62, 550 ± 60, and 711 ± 69 ml/min below the heart (P different responses depending on limb position. To determine whether these differences were due to mechanisms intrinsic to the arterial wall, a second set of experiments was performed in which acute intraluminal pressure reduction for 0.5 min, 1 min, 2 min, or 5 min was performed in isolated rat soleus feed arteries (n = 12). The magnitude of dilation upon pressure restoration was greater when acute pressure reduction occurred from 85 mmHg (mimicking pressure in the arm below the heart; 28.3 ± 7.9, 37.5 ± 5.9, 55.1 ± 9.9, and 68.9 ± 8.6% dilation) than from 48 mmHg (mimicking pressure in the arm above the heart; 20.8 ± 4.8, 22.6 ± 4.4, 31.2 ± 5.8, and 49.2 ± 7.1% dilation). These data support the hypothesis that arm position differences in reactive hyperemia are at least partially mediated by mechanisms intrinsic to the arterial wall. Overall, these results suggest the need to reevaluate studies employing positional

  16. Atomic pairwise distribution function analysis of the amorphous phase prepared by different manufacturing routes

    DEFF Research Database (Denmark)

    Boetker, Johan P.; Koradia, Vishal; Rades, Thomas

    2012-01-01

    was subjected to quench cooling thereby creating an amorphous form of the drug from both starting materials. The milled and quench cooled samples were, together with the crystalline starting materials, analyzed with X-ray powder diffraction (XRPD), Raman spectroscopy and atomic pair-wise distribution function...... (PDF) analysis of the XRPD pattern. When compared to XRPD and Raman spectroscopy, the PDF analysis was superior in displaying the difference between the amorphous samples prepared by milling and quench cooling approaches of the two starting materials....

  17. Visualization and measurement of gas-liquid metal two-phase flow with large density difference using thermal neutrons as microscopic probes

    International Nuclear Information System (INIS)

    Saito, Y.; Hibiki, T.; Mishima, K.; Nishihara, H.; Yamamoto, A.; Kanda, K.; Tobita, Y.; Konishi, K.; Matsubayashi, M.

    1998-01-01

    In a core melt accident of a fast breeder reactor there is a possibility of boiling of fuel-steel mixture in the containment pool. In relation to safety evaluation on severe accident, it is indispensable to evaluate the recriticality of melted core. Gas-liquid two-phase flow with a large density difference is formed due to the boiling of fuel-steel mixture. Although the large density difference may affect the basic characteristics of two-phase flow, little work has been performed so far on two-phase flow with large density difference has not been performed well. In this study, visualization and void fraction measurement of gas-liquid metal two-phase flow were performed by using neutron radiography. The effect of the large density difference between gas and liquid phases on the basic flow characteristics of two-phase flow was clarified. (author)

  18. Solid Phase Radioimmunoassay for Measuring Serum Triiodothyronine and Thyroxine using Different Preparations of Their Labeled Hormones

    International Nuclear Information System (INIS)

    El Kolaly, M.T; Mehany, N.L; Ayyoub, S.M.; Hassan, S.E.M.

    2005-01-01

    The goal of the present work was oriented to prepare stable polystyrene coated tubes for direct radioimmunoassay (RIA) of triiodothyronine (T 3 ) and thyroxine (T 4 ) in human serum or plasma. Coating process was performed using sheep polyclonal antisera specific for each of T 3 and T 4 . The stability study showed that these tubes could be stored for up to one year at 4 degree without any appreciable reduction in their binding. The preparations of 25 I-T 3 and 125 I-T 4 were carried out by two different methods [chloramine-T(Ch-T) and iodogen] . It was found that Ch-T method gave approximately the same results as iodogen method. Twenty five samples of different thyroid status were assayed for T 3 and T 4 using the present systems and with commerically available kits (coated tubes, DPC). The statistical analysis revealed good correlations between the results from the present systems using T 3 and T 4 tracers prepared by Ch-T and iodogen methods and The DPC kits. This may be extremely helpful in diagnosis and proper management of thyroid dysfunctions

  19. Computer Simulations of Contact Forces for Airbags with Different Folding Patterns During Deployment Phase

    Directory of Open Access Journals (Sweden)

    King H. Yang

    1995-01-01

    Full Text Available An explicit finite element method was used to study the neck load and the contact force between an occupant and an airbag during an out-of-position frontal automobile crash. Two different folding patterns and two different mounting angles of the airbag were simulated. For the four cases simulated, the occupant’s neck axial force ranged from 156 to 376% of the data obtained from in-position sled tests using the Hybrid III dummy. The neck shear force ranged from 87 to 229% and the neck flexion moment ranged from 68 to 127% of in-position experimental results. In both 300 mounting angle simulations, the neck axial forces were higher than that of the two simulations with 00 mounting angles, but the trend for the neck shear force was the opposite. Although the kinematics of the model appear reasonable, the numbers generated by the model must be reviewed with great caution because the model has not been fully validated.

  20. THE HCN/HNC ABUNDANCE RATIO TOWARD DIFFERENT EVOLUTIONARY PHASES OF MASSIVE STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Mihwa; Lee, Jeong-Eun [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Kim, Kee-Tae, E-mail: mihwajin.sf@gmail.com, E-mail: jeongeun.lee@khu.ac.kr, E-mail: ktkim@kasi.re.kr [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

    2015-07-20

    Using the H{sup 13}CN and HN{sup 13}C J = 1–0 line observations, the abundance ratio of HCN/HNC has been estimated for different evolutionary stages of massive star formation: infrared dark clouds (IRDCs), high-mass protostellar objects (HMPOs), and ultracompact H ii regions (UCH iis). IRDCs were divided into “quiescent IRDC cores (qIRDCc)” and “active IRDC cores (aIRDCc),” depending on star formation activity. The HCN/HNC ratio is known to be higher at active and high temperature regions related to ongoing star formation, compared to cold and quiescent regions. Our observations toward 8 qIRDCc, 16 aIRDCc, 23 HMPOs, and 31 UCH iis show consistent results; the ratio is 0.97 (±0.10), 2.65 (±0.88), 4.17 (±1.03), and 8.96 (±3.32) in these respective evolutionary stages, increasing from qIRDCc to UCH iis. The change of the HCN/HNC abundance ratio, therefore, seems directly associated with the evolutionary stages of star formation, which have different temperatures. One suggested explanation for this trend is the conversion of HNC to HCN, which occurs effectively at higher temperatures. To test the explanation, we performed a simple chemical model calculation. In order to fit the observed results, the energy barrier of the conversion must be much lower than the value provided by theoretical calculations.

  1. Terahertz-wave surface-emitted difference-frequency generation without quasi-phase-matching technique.

    Science.gov (United States)

    Avetisyan, Yuri H

    2010-08-01

    A scheme of terahertz (THz)-wave surface-emitted difference-frequency generation (SEDFG), which lacks the drawbacks associated with the usage of periodically orientation-inverted structures, is proposed. It is shown that both material birefringence of the bulk LiNbO(3) crystal and modal birefringence of GaAs/AlAs waveguide are sufficient to obtain SEDFG up to a frequency of approximately 3THz. The simplicity of the proposed scheme, along with the fact that there is a much smaller THz-wave decay in nonlinear crystal, makes it a good candidate for the practical realization of efficient THz generation. The use of a GaAs waveguide with an oxidized AlAs layer is proposed for enhanced THz-wave SEDFG in the vicinity of the GaAs polariton resonance at 8THz.

  2. Tungsten oxides. I. Effects of oxygen vacancies and doping on electronic and optical properties of different phases of WO3

    Science.gov (United States)

    Migas, D. B.; Shaposhnikov, V. L.; Rodin, V. N.; Borisenko, V. E.

    2010-11-01

    In this part we present results of our ab initio calculations indicating that dispersion of the bands near the gap region for different phases of WO3 (namely, ɛ-WO3, δ-WO3, γ-WO3, β-WO3, orth-WO3, α-WO3, and hex-WO3) is rather close. The rapid increase in the absorption coefficient starts at the lower energy range for α-WO3 and hex-WO3 than for the other phases in accordance with the calculated band gaps. An oxygen vacancy has turned out to decrease the gap by 0.50 eV and to shift the absorption coefficient to the lower energy range in the room temperature γ-WO3 phase. We have also traced changes caused by molybdenum and sulfur doping of γ-WO3. Only sulfur doped γ-WO3 has been revealed to display the formation of the impurity band along with a sizable reduction in the gap and the shift in the absorption coefficient to the lower energy range.

  3. Phase Behavior and Evaporation Profile of Tween 20 - Eugenol System. Effect of Different Alkane Chain Length and Solvent System

    International Nuclear Information System (INIS)

    Kassim, A.; Lim, W.H.; Kuangl, D.; Rusmawati, W.W.M.; Abdullah, A.H.; Teoh, S.P.

    2003-01-01

    The isotropic region of Tween 20/eugenol/n-alkane in aqueous systems was determined. The solubilisation trend of isotropic solution formed in the presence of eugenol was studied as a function of different alkyl chain length of n-alkane. The solubility of solvent in surfactant solution is dependent on their molecular polarity. An increase in n-alkane chain length (lower polarity) lead to smaller isotropic region which will affect the surfactant partitioning between the interface, the oil phase and the aqueous phase of the microemulsion as the oil chain length is varied. The changes of evaporation behaviour were affected strongly by the types of phases existed in the systems. The increment of n-alkane and water content led to higher evaporation rate. But the formation of w/o microemulsion would lower the evaporation rate because water molecules were trapped in the core of aggregates. In solubilisation system, evaporation rate is dependent on the solvent content and the interaction between Tween 20 and solvent molecules in the mixed composition. (author)

  4. Pure phase LaFeO3 perovskite with improved surface area synthesized using different routes and its characterization

    International Nuclear Information System (INIS)

    Gosavi, Priti V.; Biniwale, Rajesh B.

    2010-01-01

    Three different wet chemistry routes, namely co-precipitation, combustion and sol-gel methods were used to synthesize LaFeO 3 perovskite with improved surface area. The synthesized perovskite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), Brunauer-Emmett-Teller (BET) nitrogen adsorption, ultraviolet diffused reflectance spectroscopy (UVDRS) and Fourier transform infrared (FTIR) spectroscopy techniques. Improved surface area was observed for all three methods as compared to the previously reported values. The perovskite synthesized using sol-gel method yields comparatively pure, crystalline phase of LaFeO 3 and relatively higher surface area of 16.5 m 2 g -1 and porosity. The material synthesized using co-precipitation method yielded other phases in addition to the targeted phase. The morphology of perovskite synthesized using co-precipitation method was uniform agglomerates. Combustion method yields flakes type morphology and that of sol-gel method was open pore type morphology. The selection of method for perovskite synthesis largely depends on the targeted application and the desired properties of perovskites. The results reported in this study are useful for establishing a simple scalable method for preparation of high surface area LaFeO 3 as compared to solid-oxide method. Further, the typical heating cycle followed for calcinations resulted in relatively high surface area in the case of all three methods.

  5. Gibbs free-energy difference between the glass and crystalline phases of a Ni-Zr alloy

    Science.gov (United States)

    Ohsaka, K.; Trinh, E. H.; Holzer, J. C.; Johnson, W. L.

    1993-01-01

    The heats of eutectic melting and devitrification, and the specific heats of the crystalline, glass, and liquid phases have been measured for a Ni24Zr76 alloy. The data are used to calculate the Gibbs free-energy difference, Delta G(AC), between the real glass and the crystal on an assumption that the liquid-glass transition is second order. The result shows that Delta G(AC) continuously increases as the temperature decreases in contrast to the ideal glass case where Delta G(AC) is assumed to be independent of temperature.

  6. Optical UWB pulse generator using an N tap microwave photonic filter and phase inversion adaptable to different pulse modulation formats.

    Science.gov (United States)

    Bolea, Mario; Mora, José; Ortega, Beatriz; Capmany, José

    2009-03-30

    We propose theoretically and demonstrate experimentally an optical architecture for flexible Ultra-Wideband pulse generation. It is based on an N-tap reconfigurable microwave photonic filter fed by a laser array by using phase inversion in a Mach-Zehnder modulator. Since a large number of positive and negative coefficients can be easily implemented, UWB pulses fitted to the FCC mask requirements can be generated. As an example, a four tap pulse generator is experimentally demonstrated which complies with the FCC regulation. The proposed pulse generator allows different pulse modulation formats since the amplitude, polarity and time delay of generated pulse is controlled.

  7. Uncertainty propagation for flood forecasting in the Alps: different views and impacts from MAP D-PHASE

    Directory of Open Access Journals (Sweden)

    M. W. Rotach

    2012-08-01

    Full Text Available D-PHASE was a Forecast Demonstration Project of the World Weather Research Programme (WWRP related to the Mesoscale Alpine Programme (MAP. Its goal was to demonstrate the reliability and quality of operational forecasting of orographically influenced (determined precipitation in the Alps and its consequences on the distribution of run-off characteristics. A special focus was, of course, on heavy-precipitation events.

    The D-PHASE Operations Period (DOP ran from June to November~2007, during which an end-to-end forecasting system was operated covering many individual catchments in the Alps, with their water authorities, civil protection organizations or other end users. The forecasting system's core piece was a Visualization Platform where precipitation and flood warnings from some 30 atmospheric and 7 hydrological models (both deterministic and probabilistic and corresponding model fields were displayed in uniform and comparable formats. Also, meteograms, nowcasting information and end user communication was made available to all the forecasters, users and end users. D-PHASE information was assessed and used by some 50 different groups ranging from atmospheric forecasters to civil protection authorities or water management bodies.

    In the present contribution, D-PHASE is briefly presented along with its outstanding scientific results and, in particular, the lessons learnt with respect to uncertainty propagation. A focus is thereby on the transfer of ensemble prediction information into the hydrological community and its use with respect to other aspects of societal impact. Objective verification of forecast quality is contrasted to subjective quality assessments during the project (end user workshops, questionnaires and some general conclusions concerning forecast demonstration projects are drawn.

  8. Decision making process and emergency management in different phases of a nuclear accident

    International Nuclear Information System (INIS)

    Duranova, T.

    2005-01-01

    EVATECH, Information Requirements and Countermeasure Evaluation Techniques in Nuclear Emergency Management, was a research project in the key action 'Nuclear Fission' of the fifth EURATOM Framework Programme (FP5). The overall objective of the project was to enhance the quality and coherence of response to nuclear emergencies in Europe by improving the decision support methods, models and processes in ways that take into account the expectations and concern of the many different parties involved - stake holders both in managing the emergency response and those who are affected by the consequences of nuclear emergencies. The project had ten partners from seven European countries. The development of the real-time online decision support system RODOS has been one of the major items in the area of radiation protection within the European Commission's Framework Programmes. The main objectives of the RODOS project have been to develop a comprehensive and integrated decision support system that is generally applicable across Europe and to provide a common framework for incorporating the best features of existing decision support systems and future developments. Furthermore the objective has been to provide greater transparency in the decision process to: improve public understanding and acceptance of off-site emergency measures, to facilitate improved communication between countries of monitoring data, predictions of consequences, etc., in the event of any future accident, and to promote, through the development and use of the system, a more coherent, consistent and harmonised response to any future accident that may affect Europe. (authors)

  9. Properties of n-eicosane-filled microcapsules with different morphology. Phase Change Materials studied by positron spectroscopy and complementary methods

    Energy Technology Data Exchange (ETDEWEB)

    Zgardzińska, B., E-mail: bozena.zgardzinska@poczta.umcs.lublin.pl [Department of Nuclear Methods, Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Sklodowskiej 1, 20-031 Lublin (Poland); Filipek, M. [Department of Nuclear Methods, Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Sklodowskiej 1, 20-031 Lublin (Poland); Fortuniak, W. [Center of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Łódź (Poland); Mroczek, P. [Department of Geoecology and Palaeogeography, Faculty of Earth Sciences and Spatial Management, Maria Curie-Sklodowska University, Al. Kraśnicka 2cd, 20-718 Lublin (Poland)

    2016-07-01

    The Positron Annihilation Lifetime Spectroscopy (PALS) was used to investigate properties of selected Phase Change Materials (PCMs) as a function of temperature from 123 K to 333 K. Three different PCM microcapsules investigated in this work were built of n-eicosane filling and a siloxane polymer as a shell material. It has been found that the properties of ortho-positronium (o-Ps) annihilating in n-eicosane filler depend on the microcapsule morphology. In the samples where the whole interior is composed of n-eicosane and the polymer forms the outer shell only, the n-eicosane behaves like a neat macroscopic sample. In the microcapsules containing the network of polymer threads inside the globule, n-eicosane shows no rise of o-Ps intensity with time which is typical for all pure alkanes. For this morphology, the melting point of n-eicosane is preceded by the 4 K wide temperature range, where the structure resembling the rotator phase is observed (rotator phase appears in neat even-numbered alkanes with carbon chain over 20 atoms). Supplementary data were obtained by the DSC method. SEM images confirmed the morphological differentiation of microcapsules. Low temperature (close to liquid nitrogen) destroys the structure of microcapsules, particularly their outer shell. - Highlights: • Polymer-alkane microcapsules were synthesized with different morphology. • Morphological diversity of microcapsules is reflected in the parameters of the PALS. • PALS show the effect of spatial limitations on the formation of lamellar structure. • PALS is a new way to determine the percentage of microcapsules components.

  10. Formation of polycrystalline MgB2 synthesized by powder in sealed tube method with different initial boron phase

    Science.gov (United States)

    Yudanto, Sigit Dwi; Imaduddin, Agung; Kurniawan, Budhy; Manaf, Azwar

    2018-04-01

    Magnesium diboride, MgB2 is a new high critical temperature superconductor that discovered in the beginning of the 21st century. The MgB2 has a simple crystal structure and a high critical temperature, which can be manufactured in several forms like thin films, tapes, wires including bulk in the large scale. For that reason, the MgB2 has good prospects for various applications in the field of electronic devices. In the current work, we have explored the synthesis of MgB2 polycrystalline using powder in a sealed tube method. Different initial boron phase for the synthesized of MgB2 polycrystalline were used. These were, in addition to magnesium powders, crystalline boron, amorphous boron and combination both of them were respectively fitted in the synthesis. The raw materials were mixed in a stoichiometric ratio of Mg: B=1:2, ground using agate mortar, packed into stainless steel SS304. The pack was then sintered at temperature of 800°C for 2 hours in air atmosphere. Phase formation of MgB2 polycrystalline in difference of initial boron phase was characterized using XRD and SEM. Referring to the diffraction pattern and microstructure observation, MgB2 polycrystalline was formed, and the formation was effective when using the crystalline Mg and fully amorphous B as the raw materials. The critical temperature of the specimen was evaluated by the cryogenic magnet. The transition temperature of the MgB2 specimen synthesized using crystalline magnesium and full amorphous boron is 42.678 K (ΔTc = 0.877 K).

  11. A generalized volumetric dispersion model for a class of two-phase separation/reaction: finite difference solutions

    Science.gov (United States)

    Siripatana, Chairat; Thongpan, Hathaikarn; Promraksa, Arwut

    2017-03-01

    This article explores a volumetric approach in formulating differential equations for a class of engineering flow problems involving component transfer within or between two phases. In contrast to conventional formulation which is based on linear velocities, this work proposed a slightly different approach based on volumetric flow-rate which is essentially constant in many industrial processes. In effect, many multi-dimensional flow problems found industrially can be simplified into multi-component or multi-phase but one-dimensional flow problems. The formulation is largely generic, covering counter-current, concurrent or batch, fixed and fluidized bed arrangement. It was also intended to use for start-up, shut-down, control and steady state simulation. Since many realistic and industrial operation are dynamic with variable velocity and porosity in relation to position, analytical solutions are rare and limited to only very simple cases. Thus we also provide a numerical solution using Crank-Nicolson finite difference scheme. This solution is inherently stable as tested against a few cases published in the literature. However, it is anticipated that, for unconfined flow or non-constant flow-rate, traditional formulation should be applied.

  12. Determination of electrostatic force and its characteristics based on phase difference by amplitude modulation atomic force microscopy

    Science.gov (United States)

    Wang, Kesheng; Cheng, Jia; Yao, Shiji; Lu, Yijia; Ji, Linhong; Xu, Dengfeng

    2016-12-01

    Electrostatic force measurement at the micro/nano scale is of great significance in science and engineering. In this paper, a reasonable way of applying voltage is put forward by taking an electrostatic chuck in a real integrated circuit manufacturing process as a sample, applying voltage in the probe and the sample electrode, respectively, and comparing the measurement effect of the probe oscillation phase difference by amplitude modulation atomic force microscopy. Based on the phase difference obtained from the experiment, the quantitative dependence of the absolute magnitude of the electrostatic force on the tip-sample distance and applied voltage is established by means of theoretical analysis and numerical simulation. The results show that the varying characteristics of the electrostatic force with the distance and voltage at the micro/nano scale are similar to those at the macroscopic scale. Electrostatic force gradually decays with increasing distance. Electrostatic force is basically proportional to the square of applied voltage. Meanwhile, the applicable conditions of the above laws are discussed. In addition, a comparison of the results in this paper with the results of the energy dissipation method shows the two are consistent in general. The error decreases with increasing distance, and the effect of voltage on the error is small.

  13. Experimental Investigation of Two-Phase Oil (D130)-Water Flow in 4″ Pipe for Different Inclination Angles

    Science.gov (United States)

    Shaahid, S. M.; Basha, Mehaboob; Al-Hems, Luai M.

    2018-03-01

    Oil and water are often produced and transported together in pipelines that have various degrees of inclination from the horizontal. The flow of two immiscible liquids oil and water in pipes has been a research topic since several decades. In oil and chemical industries, knowledge of the frictional pressure loss in oil-water flows in pipes is necessary to specify the size of the pump required to pump the emulsions. An experimental investigation has been carried out for measurement of pressure drop of oil (D130)-water two-phase flows in 4 inch diameter inclined stainless steel pipe at different flow conditions. Experiments were conducted for different inclination angles including; 0°, 15°, 30° (for water cuts “WC” 0 - 100%). The flow rates at the inlet were varied from 4000 to 8000 barrels-per-day (BPD). For a given flow rate the frictional pressure drop has been found to increase (for all angles) from WC = 0 - 60%, and thereafter friction pressure drop decreases, this could be due phase inversion. For a given WC 40%, the frictional pressure drop has been found to increase with angle and flow rate. It has been noticed that inclination angle has appreciable effect on frictional pressure drop.

  14. Effect of different strain distributions on the phase transformations in steel. Einfluss verschiedener Dehnungszustaende auf das Umwandlungsverhalten eines Stahls

    Energy Technology Data Exchange (ETDEWEB)

    Lyra, A.; Dahl, W. (Technische Hochschule Aachen (Germany, F.R.). Inst. fuer Eisenhuettenkunde)

    1990-01-01

    Using tensile specimens with two different geometries (notched and unnotched) and five cooling rates the anisothermal phase transformation of a 100 Cr 6 steel has been investigated under influence of different strain distributions inside the specimens. The nonhomogeneous distribution of plastic strain has been achieved by tensile testing at high temperatures (800deg C). Measurement of the transformation temperatures was carried out by dilatometry and differential thermal analysis (DTA). The results reveal that due to hot deformation the pearlitic transformation curves in the CCT-Diagram are dislocated to shorter times and higher temperatures compared with the underformed state. The extent of the displacement is however a function of the strain distribution inside the specimens. (orig.).

  15. Measurement of electromagnetic waves in ELF and VLF bands to monitor lightning activity in the Maritime Continent

    Science.gov (United States)

    Yamashita, Kozo; Takahashi, Yukihiro; Ohya, Hiroyo; Tsuchiya, Fuminori; Sato, Mitsuteru; Matsumoto, Jun

    2013-04-01

    Data of lightning discharge has been focused on as an effective way for monitoring and nowcasting of thunderstorm activity which causes extreme weather. Spatial distribution of lightning discharge has been used as a proxy of the presence or absence of deep convection. Latest observation shows that there is extremely huge lightning whose scale is more than hundreds times bigger than that of averaged event. This result indicates that lightning observation should be carried out to estimate not only existence but also scale for quantitative evaluation of atmospheric convection. In this study, lightning observation network in the Maritime Continent is introduced. This network is consisted of the sensors which make possible to measure electromagnetic wave radiated from lightning discharges. Observation frequency is 0.1 - 40 kHz for the measurement of magnetic field and 1 - 40 kHz for that of electric field. Sampling frequency is 100 kHz. Waveform of electromagnetic wave is recorded by personal computer. We have already constructed observation stations at Tainan in Taiwan (23.1N, 121.1E), Saraburi in Thailand (14.5N, 101.0E), and Pontianak in Indonesia (0.0N, 109.4E). Furthermore, we plan to install the monitoring system at Los Banos in Philippines (14.18, 121.25E) and Hanoi in Viet Nam. Data obtained by multipoint observation is synchronized by GPS receiver installed at each station. By using data obtained by this network, location and scale of lightning discharge can be estimated. Location of lightning is determined based on time of arrival method. Accuracy of geolocation could be less than 10km. Furthermore, charge moment is evaluated as a scale of each lightning discharge. It is calculated from electromagnetic waveform in ELF range (3-30 kHz). At the presentation, we will show the initial result about geolocation for source of electromagnetic wave and derivation of charge moment value based on the measurement of ELF and VLF sferics.

  16. Differential benefits of amoxicillin-metronidazole in different phases of periodontal therapy in a randomized controlled crossover clinical trial.

    Science.gov (United States)

    Mombelli, Andrea; Almaghlouth, Adnan; Cionca, Norbert; Courvoisier, Delphine S; Giannopoulou, Catherine

    2015-03-01

    The specific advantage of administering systemic antibiotics during initial, non-surgical therapy or in the context of periodontal surgery is unclear. This study assesses the differential outcomes of periodontal therapy supplemented with amoxicillin-metronidazole during either the non-surgical or the surgical treatment phase. This is a single-center, randomized placebo-controlled crossover clinical trial with a 1-year follow-up. Eighty participants with Aggregatibacter actinomycetemcomitans-associated moderate to advanced periodontitis were randomized into two treatment groups: group A, antibiotics (500 mg metronidazole plus 375 mg amoxicillin three times per day for 7 days) during the first, non-surgical phase of periodontal therapy (T1) and placebo during the second, surgical phase (T2); and group B, placebo during T1 and antibiotics during T2. The number of sites with probing depth (PD) >4 mm and bleeding on probing (BOP) per patient was the primary outcome. A total of 11,212 sites were clinically monitored on 1,870 teeth. T1 with antibiotics decreased the number of sites with PD >4 mm and BOP per patient significantly more than without (group A: from 34.5 to 5.7, 84%; group B: from 28.7 to 8.7, 70%; P antibiotics, but only eight treated with placebo, achieved a 10-fold reduction of diseased sites (P = 0.007). Consequently, fewer patients of group A needed additional therapy, the mean number of surgical interventions was lower, and treatment time in T2 was shorter. Six months after T2, the mean number of residual pockets (group A: 2.8 ± 5.2; group B: 2.2 ± 5.0) was not significantly different and was sustained over 12 months in both groups. Giving the antibiotics during T1 or T2 yielded similar long-term outcomes, but antibiotics in T1 resolved the disease quicker and thus reduced the need for additional surgical intervention.

  17. A re-examination of impulsive VLF signals in the night ionosphere of Venus

    International Nuclear Information System (INIS)

    Russell, C.T.; Singh, R.N.

    1989-01-01

    Singh and Russell (1986) reported that impulsive electrical signals observed by the Pioneer Venus Orbiter Electric Field Detector at all frequencies clustered about periapsis. However, the impulsive signals consist of both signals entering the instrument through the antenna and artificial pulses associated with telemetry errors as Taylor and Cloutier (1988) have pointed out. Obvious telemetry errors were not included in the original study but records of which signals were thought to be naturally occurring and which were thought to be telemetry noise were not kept. Thus the authors cannot check the original identifications on a point-by-point basis. The authors can, however, repeat the study and compare statistical results. This study indicates that there is naturally occurring noise in the dark ionosphere of Venus near periapsis as originally reported by Singh and Russell. However, the absolute rates of occurrence of the original study and the present work differ. These differences may be due to the use of a higher threshold in the earlier study together with the lack of sufficient discrimination against telemetry dropouts. The rates of naturally occurring emissions also differ from the non-spike noise rates obtained by Taylor and Cloutier although rates of artificial signals are similar

  18. The genetic basis of strain-dependent differences in the early phase of radiation injury in mouse lung

    International Nuclear Information System (INIS)

    Franko, A.J.; Sharplin, J.; Ward, W.F.; Hinz, J.M.

    1991-01-01

    Substantial differences between mouse strains have been reported in the lesions present in the lung during the early phase of radiation injury. Some strains show only classical pneumonitis, while other strains develop substantial fibrosis and hyaline membranes which contribute appreciably to respiratory insufficiency, in addition to pneumonitis. Other strains are intermediate between these extremes. These differences correlate with intrinsic differences in activities of lung plasminogen activator and angiotensin converting enzyme. The genetic basis of these differences was assessed by examining histologically the early reaction in lungs of seven murine hybrids available commercially after whole-thorax irradiation. Crosses between fibrosing and nonfibrosing parents were uniformly nonfibrosing, and crosses between fibrosing and intermediate parents were uniformly intermediate. No evidence of sex linkage was seen. Thus the phenotype in which fibrosis is found is controlled by autosomal recessive determinants. Strains prone to radiation-induced pulmonary fibrosis and hyaline membranes exhibited intrinsically lower activities of lung plasminogen activator and angiotensin converting enzyme than either the nonfibrosing strains or the nonfibrosing hybrid crosses. The median time of death of the hybrids was genetically determined primarily by the longest-lived parent regardless of the types of lesions expressed

  19. A closed-form solution for moving source localization using LBI changing rate of phase difference only

    Directory of Open Access Journals (Sweden)

    Zhang Min

    2014-04-01

    Full Text Available Due to the deficiencies in the conventional multiple-receiver localization systems based on direction of arrival (DOA such as system complexity of interferometer or array and amplitude/phase unbalance between multiple receiving channels and constraint on antenna configuration, a new radiated source localization method using the changing rate of phase difference (CRPD measured by a long baseline interferometer (LBI only is studied. To solve the strictly nonlinear problem, a two-stage closed-form solution is proposed. In the first stage, the DOA and its changing rate are estimated from the CRPD of each observer by the pseudolinear least square (PLS method, and then in the second stage, the source position and velocity are found by another PLS minimization. The bias of the algorithm caused by the correlation between the measurement matrix and the noise in the second stage is analyzed. To reduce this bias, an instrumental variable (IV method is derived. A weighted IV estimator is given in order to reduce the estimation variance. The proposed method does not need any initial guess and the computation is small. The Cramer–Rao lower bound (CRLB and mean square error (MSE are also analyzed. Simulation results show that the proposed method can be close to the CRLB with moderate Gaussian measurement noise.

  20. Numerical simulation of two-phase slug flow with liquid carryover in different diameter ratio T-junction

    Science.gov (United States)

    Pao, W.; Hon, L.; Saieed, A.; Ban, S.

    2017-10-01

    A smaller diameter conduit pointing at 12 o’clock position is typically hot-tapped to a horizontal laying production header in offshore platform to tap produced gas for downstream process train. This geometric feature is commonly known as T-junction. The nature of multiphase fluid splitting at the T-junction is a major operational challenge due to unpredictable production environment. Often, excessive liquid carryover occurs in the T-junction, leading to complete platform trip and halt production. This is because the downstream process train is not designed to handle excessive liquid. The objective of this research is to quantify the effect of different diameter ratio on phase separation efficiency in T-junction. The liquid carryover is modelled as two-phase air-water flow using Eulerian Mixture Model coupled with Volume of Fluid Method to mimic the slug flow in the main pipe. The focus in this paper is 0.0254 m (1 inch) diameter horizontal main arm and vertical branch arm with diameter ratio of 1.0, 0.5 and 0.3. The present research narrowed the investigation to only slug flow regime using Baker’s map as reference. The investigation found that, contrary to common believe, smaller diameter ratio T-junction perform worse than larger diameter ratio T-junction.

  1. Study on solid-liquid two-phase unsteady flow characteristics with different flow rates in screw centrifugal pump

    International Nuclear Information System (INIS)

    Li, R N; Wang, H Y; Han, W; Shen, Z J; Ma, W

    2013-01-01

    The screw centrifugal pump is used as an object, and the unsteady numerical simulation of solid-liquid two-phase flow is carried out under different flow rate conditions in one circle by choosing the two-phase flow of sand and water as medium, using the software FLUENT based on the URANS equations, combining with sliding mesh method, and choosing the Mixture multiphase flow model and the SIMPLE algorithm. The results show that, with the flow rate increasing, the change trends for the pressure on volute outlet are almost constant, the fluctuation trends of the impeller axial force have a little change, the pressure and the axial force turn to decrease on the whole, the radial force gradually increases when the impeller maximum radius passes by half a cycle near the volute outlet, and the radial force gradually decreases when the maximum radius passes by the other half a cycle in a rotation cycle. The distributions of the solid particles are very uneven under a small flow rate condition on the face. The solid particles under a big flow rate condition are distributed more evenly than the ones under a small flow rate condition on the back. The theoretical basis and reference are provided for improving its working performance

  2. Different Diversity and Distribution of Archaeal Community in the Aqueous and Oil Phases of Production Fluid From High-Temperature Petroleum Reservoirs

    Directory of Open Access Journals (Sweden)

    Bo Liang

    2018-04-01

    Full Text Available To get a better knowledge on how archaeal communities differ between the oil and aqueous phases and whether environmental factors promote substantial differences on microbial distributions among production wells, we analyzed archaeal communities in oil and aqueous phases from four high-temperature petroleum reservoirs (55–65°C by using 16S rRNA gene based 454 pyrosequencing. Obvious dissimilarity of the archaeal composition between aqueous and oil phases in each independent production wells was observed, especially in production wells with higher water cut, and diversity in the oil phase was much higher than that in the corresponding aqueous phase. Statistical analysis further showed that archaeal communities in oil phases from different petroleum reservoirs tended to be more similar, but those in aqueous phases were the opposite. In the high-temperature ecosystems, temperature as an environmental factor could have significantly affected archaeal distribution, and archaeal diversity raised with the increase of temperature (p < 0.05. Our results suggest that to get a comprehensive understanding of petroleum reservoirs microbial information both in aqueous and oil phases should be taken into consideration. The microscopic habitats of oil phase, technically the dispersed minuscule water droplets in the oil could be a better habitat that containing the indigenous microorganisms.

  3. Measuring the phase difference in network and residual voltages under the GTsN-195M pump self-starting

    International Nuclear Information System (INIS)

    Druba, V.V.; Druba, T.A.; Reznik, V.R.

    1989-01-01

    Determination of time dependence of phase difference of residual voltage on motor windings of the main circulation pumps (MCP) and voltage of power supply section under MCP self-starting under conditions of short-time breaks in electric power supply is one of the main problems to which reliability and safety of NPP operation is related. A method to measure this dependence in real conditions in case of MCP free run-out and run-out in generating mode is suggested. The method considered is used for tests of the Kalinin NPP-2 MCP-195M self-starting. Analysis of run-out curves in the case of a break in MCP power supply for 1.8 s shows that the most favourable conditions for MCP self-starting are 0.63±0.03 s after de-energizing. 2 refs.; 3 figs.; 1 tab

  4. Comparative Effectiveness of Different Phase Change Materials to Improve Cooling Performance of Heat Sinks for Electronic Devices

    Directory of Open Access Journals (Sweden)

    Ahmad Hasan

    2016-08-01

    Full Text Available This paper thermo-physically characterizes salt hydrate, paraffin wax and milk fat as phase change materials (PCMs. The three PCMs are compared in terms of improving heat sink (HS performance for cooling electronic packaging. An experimental study is carried out on commercially available finned HS with and without PCM under natural ventilation (NV and forced ventilation (FV at different heat loads (4 W to 10 W. The results indicate that integration of all of the PCMs into the HS improves its cooling performance; however, milk fat lags behind the other two PCMs in terms of cooling produced. A three-dimensional pressure-based conjugate heat transfer model has been developed and validated with experimental results. The model predicts the parametric influence of PCM melting range, thermal conductivity and density on HS thermal management performance. The HS cooling performance improves with increased density and conductivity while it deteriorates with the wider melting range of the PCMs.

  5. Room Volume Estimation Based on Ambiguity of Short-Term Interaural Phase Differences Using Humanoid Robot Head

    Directory of Open Access Journals (Sweden)

    Ryuichi Shimoyama

    2016-07-01

    Full Text Available Humans can recognize approximate room size using only binaural audition. However, sound reverberation is not negligible in most environments. The reverberation causes temporal fluctuations in the short-term interaural phase differences (IPDs of sound pressure. This study proposes a novel method for a binaural humanoid robot head to estimate room volume. The method is based on the statistical properties of the short-term IPDs of sound pressure. The humanoid robot turns its head toward a sound source, recognizes the sound source, and then estimates the ego-centric distance by its stereovision. By interpolating the relations between room volume, average standard deviation, and ego-centric distance experimentally obtained for various rooms in a prepared database, the room volume was estimated by the binaural audition of the robot from the average standard deviation of the short-term IPDs at the estimated distance.

  6. Gender differences on the job satisfaction in the phase of implementing advanced manufacturing technology in the Chinese manufacturing firms.

    Science.gov (United States)

    Yu, Na; Shen, Li Ming; Lewark, Siegfried

    2012-01-01

    This research gave an effort to study on gender differences in the job satisfaction for technological innovation at Chinese manufacturing firm. The exploratory study was conducted in four Chinese furniture manufacturing firms, which are all in the phases of introducing advanced manufacturing system. The results of statistical analysis show that general satisfaction of female employees to their jobs is significantly higher than male employees. In addition, supervisory satisfaction of female employees is significantly higher than male employees. The findings of the study reveal that activities are suggested to be carried out to increase the job satisfaction of male employees, especially improve communication and relationship between the managerial and the non-managerial levels in the innovation process. In addition, the higher job satisfaction of female employees could be considered a positive factor for the successful implementation of AMT in the technological innovation, although male employees are still dominated work force in the case study firms.

  7. Comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement

    International Nuclear Information System (INIS)

    Stumberger, Bojan; Stumberger, Gorazd; Hadziselimovic, Miralem; Hamler, Anton; Gorican, Viktor; Jesenik, Marko; Trlep, Mladen

    2007-01-01

    The paper presents a comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement. Motors with the following permanent magnet topologies were accounted for in the comparison: the surface-mounted permanent magnet synchronous motor (SMPMSM), the interior permanent magnet synchronous motor (IPMSM), the permanent magnet-assisted synchronous reluctance motor (PMASRM) and the flux reversal permanent magnet motor (FRPMM). Finite element method analysis is employed to determine the performance of each motor. Calculated performance of four-pole IPMSM determined by finite element method calculation is confirmed with the measurements at nearly constant nominal output power in the range of speed 3000-10,000 rpm

  8. Electromagnetic field measurements in ULF-ELF-VLF [0.001 Hz─100 KHz] bands

    Directory of Open Access Journals (Sweden)

    C. Di Lorenzo

    2008-01-01

    Full Text Available We are reporting the technological and scientific objectives of the MEM project. The MEM project has been activated in the INGV Observatory of L'Aquila to create in Central Italy a network of observatories in order to monitoring the electromagnetic signals in the frequency band [0.001 Hz–100 kHz]. Some examples of the instrumentation developed in the frame of the project are reported. An innovative technique, based on the wide band interferometry is proposed to obtain detailed information concerning the several detected electromagnetic sources. Moreover, data from each station will be elaborated to investigate different sectors as the structure of ground electric conductibility, the electromagnetic phenomena connected with seismic activity, the separation of the electromagnetic fields originated in the Earth's interior and the electromagnetic phenomena originated in the magnetosphere, in the ionosphere and in the Earth-ionosphere cavity.

  9. Comparison of type 2 diabetes mellitus incidence in different phases of hepatitis B virus infection: A meta-analysis.

    Science.gov (United States)

    Shen, Yi; Zhang, Sheng; Wang, Xulin; Wang, Yuanyuan; Zhang, Jian; Qin, Gang; Li, Wenchao; Ding, Kun; Zhang, Lei; Liang, Feng

    2017-10-01

    Because whether hepatitis B virus infection increases the risk of type 2 diabetes mellitus has been a controversial topic, pair-wise and network meta-analyses of published literature were carried out to accurately evaluate the association between different phases of hepatitis B virus infection and the risk of type 2 diabetes mellitus. A comprehensive literature retrieval was conducted from the PubMed, Embase, Cochrane Library and Chinese Database to identify epidemiological studies on the association between hepatitis B virus infection and the risk of type 2 diabetes mellitus that were published from 1999 to 2015. A pair-wise meta-analysis of direct evidence was performed to estimate the pooled odds ratios and 95% confidence intervals. A network meta-analysis was conducted, including the construction of a network plot, inconsistency plot, predictive interval plot, comparison-adjusted funnel plot and rank diagram, to graphically link the direct and indirect comparisons between different hepatitis B virus infective phases. Eighteen publications (n=113 639) describing 32 studies were included in this meta-analysis. In the pair-wise meta-analysis, the pooled odds ratio for type 2 diabetes mellitus in chronic hepatitis B cirrhosis patients was 1.76 (95% confidence interval: 1.44-2.14) when compared with non-cirrhotic chronic hepatitis B patients. In the network meta-analysis, six comparisons of four hepatitis B virus infectious states indicated the following descending order for the risk of type 2 diabetes mellitus: hepatitis B cirrhosis patients, non-cirrhotic chronic hepatitis B patients, hepatitis B virus carriers and non-hepatitis B virus controls. This study suggests that hepatitis B virus infection is not an independent risk factor for type 2 diabetes mellitus, but the development of cirrhosis may increase the incidence of type 2 diabetes mellitus cirrhosis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Co-crystallization phase transformations in all π-conjugated block copolymers with different main-chain moieties.

    Science.gov (United States)

    Lee, Yi-Huan; Chen, Wei-Chih; Yang, Yi-Lung; Chiang, Chi-Ju; Yokozawa, Tsutomu; Dai, Chi-An

    2014-05-21

    Driven by molecular affinity and balance in the crystallization kinetics, the ability to co-crystallize dissimilar yet self-crystallizable blocks of a block copolymer (BCP) into a uniform domain may strongly affect its phase diagram. In this study, we synthesize a new series of crystalline and monodisperse all-π-conjugated poly(2,5-dihexyloxy-p-phenylene)-b-poly(3-(2-ethylhexyl)thiophene) (PPP-P3EHT) BCPs and investigate this multi-crystallization effect. Despite vastly different side-chain and main-chain structures, PPP and P3EHT blocks are able to co-crystallize into a single uniform domain comprising PPP and P3EHT main-chains with mutually interdigitated side-chains spaced in-between. With increasing P3EHT fraction, PPP-P3EHTs undergo sequential phase transitions and form hierarchical superstructures including predominately PPP nanofibrils, co-crystalline nanofibrils, a bilayer co-crystalline/pure P3EHT lamellar structure, a microphase-separated bilayer PPP-P3EHT lamellar structure, and finally P3EHT nanofibrils. In particular, the presence of the new co-crystalline lamellar structure is the manifestation of the interaction balance between self-crystallization and co-crystallization of the dissimilar polymers on the resulting nanostructure of the BCP. The current study demonstrates the co-crystallization nature of all-conjugated BCPs with different main-chain moieties and may provide new guidelines for the organization of π-conjugated BCPs for future optoelectronic applications.

  11. Enantiomeric separation of type I and type II pyrethroid insecticides with different chiral stationary phases by reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Zhang, Ping; Yu, Qian; He, Xiulong; Qian, Kun; Xiao, Wei; Xu, Zhifeng; Li, Tian; He, Lin

    2018-04-01

    The enantiomeric separation of type I (bifenthrin, BF) and type II (lambda-cyhalothrin, LCT) pyrethroid insecticides on Lux Cellulose-1, Lux Cellulose-3, and Chiralpak IC chiral columns was investigated by reversed-phase high-performance liquid chromatography. Methanol/water or acetonitrile/water was used as mobile phase at a flow rate of 0.8 mL/min. The effects of chiral stationary phase, mobile phase composition, column temperature, and thermodynamic parameters on enantiomer separation were carefully studied. Bifenthrin got a partial separation on Lux Cellulose-1 column and baseline separation on Lux Cellulose-3 column, while LCT enantiomers could be completely separated on both Lux Cellulose-1 and Lux Cellulose-3 columns. Chiralpak IC provided no separation ability for both BF and LCT. Retention factor (k) and selectivity factor (α) decreased with the column temperature increasing from 10°C to 40°C for both BF and LCT enantiomers. Thermodynamic parameters including ∆H and ∆S were also calculated, and the maximum R s were not always obtained at lowest temperature. Furthermore, the quantitative analysis methods for BF and LCT enantiomers in soil and water were also established. Such results provide a new approach for pyrethroid separation under reversed-phase condition and contribute to environmental risk assessment of pyrethroids at enantiomer level. © 2017 Wiley Periodicals, Inc.

  12. Phase measurements of very-low-frequency signals from the magnetosphere

    International Nuclear Information System (INIS)

    Paschal, E.V.

    1988-01-01

    The usual methods of spectrum analysis applied to analog tape recordings of very low frequency (VLF) signals extract only magnitude information and ignore phase information. A digital signal-processing system using a recorded constant-frequency pilot tone was developed that can correct tape errors due to wow and flutter, and reconstruct the signal phases. Frequency shifts are corrected during analysis by interpolating between spectral points in the windowed Fourier transform, and the output phases of the synthesized filters are corrected for timing errors. Having signal-component phases as well as magnitudes doubles the available information. Whistler-mode signals from the VLF transmitter at Siple Station, Antarctica, were analyzed as received at Roberval, Quebec. The phase of a non-growing signal is found to give a less-noisy measure of duct motion than Doppler frequency shift, with improved time resolution. Correlations are seen between variations in the whistler-mode phase delay and the earth's magnetic field component D. They are interpreted as Pc 2 micropulsation transients, short compared to the length of the field line, which propagate from equator to ground as Alfven waves

  13. Menstrual phase-related differences in the pulsatility index on the central retinal artery suggest an oestrogen vasodilatation effect that antagonizes with progesterone.

    Science.gov (United States)

    Viana, Luiz Carlos; Faria, Marcos; Pettersen, Heverton; Sampaio, Marcos; Geber, Selmo

    2011-03-01

    The actual effect of steroid hormones on cerebral microcirculation is still controversial. Therefore, the aim of our study was to investigate vascular flow variations in the central retinal artery that may exist during the ovulatory menstrual cycle. A total of 34 healthy women were included in this observational, longitudinal, and prospective study. All participants were submitted to dopplerfluxometric evaluation of the eyes in order to study the pulsatility index (PI) of the central retinal arteries, during four phases of the menstrual cycle: early follicular, mid follicular, periovulatory, and mid luteal phases. Subjects' ages ranged from 14 to 47 years old (mean: 29.7 ± 10.1) and PI did not differ among age groups. The PI of the central retinal artery was different among the four phases of the menstrual cycle. PI showed a significant decrease from early follicular phase (1.72) to mid follicular phase (1.57) (p = 0.037), and was similar during periovulatory phase (1.56) and significantly increased in mid luteal phase (1.70). After that it returned to the values observed in the early follicular phase. Our results suggest the existence of an oestrogen vasodilatation effect on the central retinal artery that is menstrual phase-related and antagonized by progesterone.

  14. The differences in matrix effect between supercritical fluid chromatography and reversed phase liquid chromatography coupled to ESI/MS.

    Science.gov (United States)

    Svan, Alfred; Hedeland, Mikael; Arvidsson, Torbjörn; Pettersson, Curt E

    2018-02-13

    For many sample matrices, matrix effects are a troublesome phenomenon using the electrospray ionization source. The increasing use of supercritical fluid chromatography with CO 2 in combination with the electrospray ionization source for MS detection is therefore raising questions: is the matrix effect behaving differently using SFC in comparison with reversed phase LC? This was investigated using urine, plasma, influent- and effluent-wastewater as sample matrices. The matrix effect was evaluated using the post-extraction addition method and through post-column infusions. Matrix effect profiles generated from the post-column infusions in combination with time of flight-MS detection provided the most valuable information for the study. The combination of both qualitative and semi-quantitative information with the ability to use HRMS-data for identifying interfering compounds from the same experiment was very useful, and has to the authors' knowledge not been used this way before. The results showed that both LC and SFC are affected by matrix effects, however differently depending on sample matrix. Generally, both suppressions and enhancements were seen, with a higher amount of enhancements for LC, where 65% of all compounds and all sample matrices were enhanced, compared to only 7% for SFC. Several interferences were tentatively identified, with phospholipids, creatinine, and metal ion clusters as examples of important interferences, with different impact depending on chromatographic technique. SFC needs a different strategy for limiting matrix interferences, owing to its almost reverse retention order compared to RPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The Use of Smartphones in Different Phases of Medical School and its Relationship to Internet Addiction and Learning Approaches.

    Science.gov (United States)

    Loredo E Silva, Mathias Paulo; de Souza Matos, Brenda Dutra; da Silva Ezequiel, Oscarina; Lucchetti, Alessandra Lamas Granero; Lucchetti, Giancarlo

    2018-04-26

    The use of smartphones is revolutionizing the way information is acquired, leading to profound modifications in teaching medicine. Nevertheless, inadvertent use can negatively affect student learning. The present study aims to evaluate smartphone use in the educational context as well as Internet addiction and its repercussions on surface and deep learning and to compare them during the different phases of medical students' education. This is a cross-sectional study involving medical students in all phases of education. Sociodemographic data, type and frequency of smartphone use, degree of digital addiction (Internet Addiction Test - IAT), and surface and deep approaches to learning (Biggs) were analyzed. A total of 710 students were included. Almost all students had a smartphone and a total of 96.8% used it during lectures, classes, and meetings. Less than half of the students (47.3%) reported using a smartphone for more than 10 min for educational purposes, a usage that is higher among clerkship students. At least 95% reported using a smartphone in the classroom for activities not related to medicine (social media and searching for general information) and 68.2% were considered problematic Internet users according to the IAT. The most common reasons for noneducational use were that the class was uninteresting, students needed to receive or make an important call, and the educational strategy was not stimulating. The "frequency of smartphone use" and higher "internet addiction" were correlated to both higher levels of surface learning and lower levels of deep learning. Educators should advise and educate their students about conscientious use of this tool to avoid detrimental impact on the learning process.

  16. Microencapsulated n-octadecane with different methylmethacrylate-based copolymer shells as phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    Qiu, Xiaolin; Li, Wei; Song, Guolin; Chu, Xiaodong; Tang, Guoyi

    2012-01-01

    Microcapsules containing n-octadecane with different methylmethacrylate (MMA (methyl methacrylate))-based copolymer shells were fabricated by a suspension-like polymerization. Butyl acrylate (BA), butyl methacrylate (BMA), lauryl methacrylate (LMA) and stearyl methacrylate (SMA) were employed as monomers to copolymerize with MMA. Pentaerythritol tetraacrylate (PETRA) was employed as a crosslinking agent. The (microencapsulted phase change materials) MicroPCMs were characterized using Fourier transformed infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Thermal properties and thermal resistances of MicroPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. Phase change enthalpies and PCM contents of MicroPCMs increased with the length decreasing of the side chain of the monomers. The n-octadecane content of as much as 77.3% can be obtained in the crosslinked MicroPCMs with P(MMA-co-BMA) as shell, and accompanied by the highest melting enthalpy (173.7 J/g) and crystallization enthalpy (174.4 J/g). Heat capacities of crosslinked MicroPCMs are higher than those of their uncrosslinked counterparts. The crosslinked MicroPCMs exhibit significantly greater thermal stabilities compared with their uncrosslinked counterparts and the n-ontadecane bulk. The crosslinked MicroPCMs with P(MMA-co-SMA) displays the highest thermal resistance temperature up to 255 °C. Therefore, MicroPCMs with MMA-based copolymer as shells, especially crosslinked copolymer shells, show excellent potentials for thermal energy storage. -- Highlights: ► n-Octadecane was encapsulated with methylmethacrylate(MMA)-based copolymer shells. ► n-Octadecane content of Microcapsules increased with length decreasing of side chain of monomers. ► Microcapsule with P(MMA-co-butyl methacrylate) has the highest latent heat. ► Microcapsule with P(MMA-co-stearyl methacrylate) has the greatest thermal stability.

  17. Effects of light and nutrients on different germination phases of the Cosmopolitan moss Bryum argenteum Hedw. (Bryaceae

    Directory of Open Access Journals (Sweden)

    Adaíses Simone Maciel da Silva

    2010-08-01

    Full Text Available The influence of light and nutrients on the different germination phases of Bryum argenteum spores was studied. The following treatments were used: distilled water and nutrient solution under light (12 h and continuous darkness. The spores germinated when exposed to light, independent of both medium used. Under darkness, the spores swelled and became chlorophyllous. In the presence of nutrient solution, the germination occurred earlier (after two days when compared to the distilled water (after more than three days. Nutrients were needed to complete the last germination phase in the majority of spores and to provide the protonemal growth.Neste estudo procuramos avaliar a importância de fatores abióticos sobre a germinação de esporos e o desenvolvimento do protonema de musgos. Para isso, nós analisamos o efeito da disponibilidade de luz e nutrientes sobre diferentes fases da germinação de esporos de um musgo amplamente distribuído. Bryum argenteum geralmente apresenta muitos esporos por cápsula, e estes são amarelos devido à presença de muitos corpúsculos lipídicos. Foram usados os tratamentos: água destilada e solução nutritiva sob luz (12 h e escuro contínuo. Os esporos mostraram-se fotoblásticos positivos, ou seja, apenas germinaram sob luz, independentemente do meio utilizado. Sob escuro os esporos apenas embeberam, tornando-se clorofilados provavelmente a partir da quebra de reservas. Em solução nutritiva a germinação ocorreu mais rapidamente (dois dias em relação à água destilada (mais de três dias após cultivo. No entanto, os nutrientes foram necessários para completar a última fase da germinação da maioria dos esporos.

  18. The immobilisation of nuclear waste materials containing different alkali elements into single-phase NZP based ceramics

    International Nuclear Information System (INIS)

    Pet'kov, V.I.; Orlova, A.I.; Trubach, I.G.; Demarin, T.; Kurazhkovskaya, V.S.

    2002-01-01

    The NZP matrix, which is based on NaZr 2 (PO 4 ) 3 , is a viable candidate for nuclear waste immobilisation. We examined the possibilities of incorporating of alkali elements into the NZP host structure, investigated the conditions of the crystalline solution formation, and determined the regions of the NZP structure compositional stability for a series of complex orthophosphates of titanium or zirconium and alkali elements A m-x A' x M 2-(m-1)/4 (PO 4 ) 3 with m = 1, 3, or 5 and 0 ≤ x ≤ m, where A and A' are mutually different alkali elements and M is Ti or Zr. The phosphates containing Li-Na, Li-K, Li-Rb, Li-Cs, Na-K, Na-Rb, Na-Cs, K-Rb, K-Cs and Rb-Cs pairs were prepared and studied by X-ray powder analysis, IR spectroscopy, simultaneous DTA-TG measurements and electron microprobe analyses. In the systems studied, wide ranges of crystalline phosphate solutions with tailored alkali metal substitutions were formed owing to the large number of sites available for substitution and high degree of flexibility in the NZP structure. It was found that introduction of the less expensive and lighter Ti in the host phase in place of the commonly used Zr permits cheaper ceramics, having in some cases larger alkali element contents, to be obtained. The phases containing alkali metals can be formed, for instance, during phosphate solidification of molten alkali chlorides with radioactive nuclides from the pyroelectrochemical technologies of nuclear fuel recycling

  19. Column Chromatography Of Co(II), Zn(II) And Eu(III) Using Pistachio Shell And Different Mobile Phases

    International Nuclear Information System (INIS)

    Abdel-Fattah, A.A.

    2009-01-01

    Pistachio shell particles (0.5-1 mm) have been applied as the stationary phase for studying the column chromatography of Co(II), Zn(II) and Eu(III) at room temperature; 26 + - 1 oC. This solid sorbent has been characterized by thermogravimetric analysis, infra-red spectroscopy and X-ray diffraction. Its surface area and percent of swelling have been also determined. Different eluting agents have been used for eluting the sorbed elements. The elution curves have been done from which the distribution coefficients (K d ), number of theoretical plates (N) and heights equivalent to theoretical plates (H) have been determined. Column performance studies have been conducted for a representative system under certain experimented conditions and Van Deemter equation has been applied. Thermodynamic studies have been applied and thermodynamic functions ( δG 0 ,δH 0 andδ S 0 ) have been calculated for this representative system by determining K d at three different room temperatures (18, 26 and 37 + - 1o C).

  20. Column Chromatography Of Co(II), Zn(II) And Eu(III) Using Pistachio Shell And Different Mobile Phases

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Fattah, A A [Nuclear Chemistry Department, Radioisotopes Production Division, Hot Laboratories Centre, Atomic Energy Authority, Cairo (Egypt)

    2009-07-01

    Pistachio shell particles (0.5-1 mm) have been applied as the stationary phase for studying the column chromatography of Co(II), Zn(II) and Eu(III) at room temperature; 26{sup +}-{sup 1}oC. This solid sorbent has been characterized by thermogravimetric analysis, infra-red spectroscopy and X-ray diffraction. Its surface area and percent of swelling have been also determined. Different eluting agents have been used for eluting the sorbed elements. The elution curves have been done from which the distribution coefficients (K{sub d}), number of theoretical plates (N) and heights equivalent to theoretical plates (H) have been determined. Column performance studies have been conducted for a representative system under certain experimented conditions and Van Deemter equation has been applied. Thermodynamic studies have been applied and thermodynamic functions ( {delta}G{sup 0} ,{delta}H{sup 0} and{delta} S{sup 0}) have been calculated for this representative system by determining K{sub d} at three different room temperatures (18, 26 and 37{sup +}-{sup 1o}C)

  1. Exploring bio-hydrogen-producing performance in three-phase fluidized bed bioreactors using different types of immobilized cells

    International Nuclear Information System (INIS)

    Shu-Yii Wu; Chi-Neng Lin; Yuan-Chang Shen; Shu-Yii Wu; Chiu-Yue Lin; Jo-Shu Chang

    2006-01-01

    In this study, the spherical activated carbon (AC) and silicone gel (SC) were used as the primary matrices to immobilize H 2 -producing activated sludge. The experiments were carried out in two different types of three-phase fluidized beds; namely, conventional fluidized bed reactor (FBR) and draft tube fluidized bed reactor (DTFBR). The solid volume of AC and SC immobilized cells was 10 vol.% for both FBR and DTFBR. Sucrose (at 20000 mg COD/l) was used as the carbon substrate for H 2 production. The H 2 -producing performance was examined at different hydraulic retention times (HRT = 8, 6, 4, 2, 1, and 0.5 h). The results show that the best volumetric H 2 production rate was 1.23 ± 0.08 l/h/l (HRT = 2 h) and 2.33 ± 0.22 l/h/l (HRT 0.5 h) for fluidized beds containing AC and SC immobilized cells, respectively. The highest H 2 yield was 3.37 mol H 2 /mol sucrose (HRT = 6 h) and 4.07 mol H 2 /mol sucrose (HRT = 4 h) for fluidized beds with AC and SC immobilized cells, respectively. The H 2 content in the biogas was stably maintained at 35% or higher for all the reactors, while the primary soluble metabolites in the cultures were acetic acid and butyric acid. (authors)

  2. Influence of Urbanization Factors on Surface Urban Heat Island Intensity: A Comparison of Countries at Different Developmental Phases

    Directory of Open Access Journals (Sweden)

    Yaoping Cui

    2016-07-01

    Full Text Available Urbanization is a global problem with demographic trends. The urban heat island plays a dominant role in local climate systems. Despite existing efforts to understand the impacts of multiple urbanization factors on the urban heat island globally, very little is known about the attribution of urban heat island magnitude to urbanization in different locations or developmental phases. In this study, based on global land surface temperature data, urban spatial domain data, gross domestic product (GDP, and population data, we analyzed the influence of multiple urbanization factors on global surface urban heat island intensity (SUHII. We also tentatively compared the abovementioned factors between different regions across the globe, especially between China and the USA, the largest countries that are experiencing or have experienced rapid urbanization in recent decades. The results showed that global SUHII had remarkable spatial heterogeneity due to the geographical and socioeconomic variation between cities. There was a significant correlation between SUHII and population as well as GDP in global cities. Moreover, this study suggested that the impacts of population on SUHII might be stronger in the early stages of urbanization, and the GDP factor would become a critical factor at a certain development level. The urban area also had non-ignorable impacts on SUHII, while the correlation between SUHII and urban shape was relatively weak. All these may imply that the best approach to slow down SUHII is to find other solutions, e.g., optimize the spatial configuration of urban internal landscapes, when the urbanization reaches a high level.

  3. Ergonomic risk assessment with DesignCheck to evaluate assembly work in different phases of the vehicle development process.

    Science.gov (United States)

    Winter, Gabriele; Schaub, Karlheinz G; Großmann, Kay; Laun, Gerhard; Landau, Kurt; Bruder, Ralph

    2012-01-01

    Occupational hazards exist, if the design of the work situation is not in accordance with ergonomic design principles. At assembly lines ergonomics is applied to the design of work equipment and tasks and to work organisation. The ignoring of ergonomic principles in planning and design of assembly work leads to unfavourable working posture, action force and material handling. Disorders of the musculoskeletal system are of a common occurrence throughout Europe. Musculoskeletal disorders are a challenge against the background of disabled workers. The changes in a worker's capability have to be regarded in the conception of redesigned and new assembly lines. In this way ergonomics becomes progressively more important in planning and design of vehicles: The objective of ergonomic design in different stages of the vehicles development process is to achieve an optimal adaptation of the assembly work to workers. Hence the ergonomic screening tool "Design Check" (DC) was developed to identify ergonomic deficits in workplace layouts. The screening-tool is based on the current ergonomic state of the art in the design of physical work and relevant EU legal requirements. It was tested within a federal German research project at selected work stations at the assembly lines at Dr.-Ing. h.c. F. Porsche AG / Stuttgart. Meanwhile the application of the screening-tool DC is transferred in other parts of the Porsche AG, Stuttgart. It is also realized as an ergonomic standard method to perform assembly work in different phases of the vehicle development process.

  4. Hyperthyroidism modifies ecto-nucleotidase activities in synaptosomes from hippocampus and cerebral cortex of rats in different phases of development.

    Science.gov (United States)

    Bruno, Alessandra Nejar; Da Silva, Rosane Souza; Bonan, Carla Denise; Battastini, Ana Maria Oliveira; Barreto-chaves, Maria Luiza M; Sarkis, João José Freitas

    2003-11-01

    Here we investigate the possible effects of the hyperthyroidism on the hydrolysis of the ATP to adenosine in the synaptosomes of hippocampus, cerebral cortex and blood serum of rats in different developmental phases. Manifestations of hyperthyroidism include anxiety, nervousness, tachycardia, physical hyperactivity and weight loss amongst others. The thyroid hormones modulate a number of physiological functions in central nervous system, including development, function, expression of adenosine A(1) receptors and transport of neuromodulator adenosine. Thus, hyperthyroidism was induced in male Wistar rats (5-, 60-, 150- and 330-day old) by daily injections of L-thyroxine (T4) for 14 days. Nucleotide hydrolysis was decreased by about 14-52% in both hippocampus and cerebral cortex in 5 to 60-day-old rats. These changes were also observed in rat blood serum. In addition, in 11-month-old rats, inhibition of ADP and AMP hydrolysis persisted in the hippocampus, whereas, in cerebral cortex, an increase in AMP hydrolysis was detected. Thus, hyperthyroidism affects the extracellular nucleotides balance and adenosine production, interfering in neurotransmitter release, development and others physiological processes in different systems.

  5. Differences and discriminatory power of water polo game-related statistics in men in international championships and their relationship with the phase of the competition.

    Science.gov (United States)

    Escalante, Yolanda; Saavedra, Jose M; Tella, Victor; Mansilla, Mirella; García-Hermoso, Antonio; Domínguez, Ana M

    2013-04-01

    The aims of this study were (a) to compare water polo game-related statistics by context (winning and losing teams) and phase (preliminary, classification, and semifinal/bronze medal/gold medal), and (b) identify characteristics that discriminate performances for each phase. The game-related statistics of the 230 men's matches played in World Championships (2007, 2009, and 2011) and European Championships (2008 and 2010) were analyzed. Differences between contexts (winning or losing teams) in each phase (preliminary, classification, and semifinal/bronze medal/gold medal) were determined using the chi-squared statistic, also calculating the effect sizes of the differences. A discriminant analysis was then performed after the sample-splitting method according to context (winning and losing teams) in each of the 3 phases. It was found that the game-related statistics differentiate the winning from the losing teams in each phase of an international championship. The differentiating variables are both offensive and defensive, including action shots, sprints, goalkeeper-blocked shots, and goalkeeper-blocked action shots. However, the number of discriminatory variables decreases as the phase becomes more demanding and the teams become more equally matched. The discriminant analysis showed the game-related statistics to discriminate performance in all phases (preliminary, classificatory, and semifinal/bronze medal/gold medal phase) with high percentages (91, 90, and 73%, respectively). Again, the model selected both defensive and offensive variables.

  6. Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions

    Directory of Open Access Journals (Sweden)

    Yuanfeng Yang

    2015-05-01

    Full Text Available The aim of this research was to investigate the influence of metallurgy on the corrosion behaviour of separate weld zone (WZ and parent plate (PP regions of X65 pipeline steel in a solution of deionised water saturated with CO2, at two different temperatures (55 °C and 80 °C and at initial pH~4.0. In addition, a non-electrochemical immersion experiment was also performed at 80 °C in CO2, on a sample portion of X65 pipeline containing part of a weld section, together with adjacent heat affected zones (HAZ and parent material. Electrochemical impedance spectroscopy (EIS was used to evaluate the corrosion behaviour of the separate weld and parent plate samples. This study seeks to understand the significance of the different microstructures within the different zones of the welded X65 pipe in CO2 environments on corrosion performance; with particular attention given to the formation of surface scales; and their composition/significance. The results obtained from grazing incidence X-ray diffraction (GIXRD measurements suggest that, post immersion, the parent plate substrate is scale free, with only features arising from ferrite (α-Fe and cementite (Fe3C apparent. In contrast, at 80 °C, GIXRD from the weld zone substrate, and weld zone/heat affected zone of the non-electrochemical sample indicates the presence of siderite (FeCO3 and chukanovite (Fe2CO3(OH2 phases. Scanning Electron Microscopy (SEM on this surface confirmed the presence of characteristic discrete cube-shaped crystallites of siderite together with plate-like clusters of chukanovite.

  7. Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa, E-mail: ferrazw@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG) Belo Horizonte, MG (Brazil)

    2011-07-01

    Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the {alpha} and {gamma} phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)

  8. Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment

    International Nuclear Information System (INIS)

    Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa

    2011-01-01

    Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the α and γ phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)

  9. Simulation Study of Active Ceilings with Phase Change Material in Office Buildings for Different National Building Regulations

    DEFF Research Database (Denmark)

    Farhan, Hajan; Stefansen, Casper; Bourdakis, Eleftherios

    2018-01-01

    The aim of this study was to examine the performance of phase change material (PCM) in active ceilings for an office room under different Danish building regulations for both heating and cooling purposes. A model of a two-person office room was simulated with the only heating and cooling source...... being radiant ceiling panels containing PCM. The target was to reduce energy use for the simulation models and still meet the recommended criteria of Category II for the European Standard EN 15251:2007 namely, 23°C – 26°C (73.4°F – 78.8°F) during summer and between 20°C – 24°C (68.0°F – 73.4°F) during...... winter. The office model was simulated for a whole year and analyzed for three Danish building regulations BR10 (2010), BR15 (2015) and BR20 (2020). The results show that the indoor environment was within the desired Category II, according to EN 15251 for the whole occupancy period. The predicted...

  10. Effect of phase change materials on indoor thermal environment under different weather conditions and over a long time

    International Nuclear Information System (INIS)

    Ling, Haoshu; Chen, Chao; Wei, Shen; Guan, Yong; Ma, Caiwen; Xie, Guangya; Li, Na; Chen, Ziguang

    2015-01-01

    Highlights: • Indicators evaluating the performance of PCMs in greenhouses are introduced. • Real equivalent specific heat capacity of PCMs is embedded in a numerical model. • Real behaviour of PCMs has been monitored over a long time. • Efficiency of PCMs walls are compared for sunny and cloudy days. • Heat storage and release amounts of PCMs walls have been calculated. - Abstract: To evaluate the effect of phase change materials (PCMs) on the indoor thermal environment of greenhouses under different weather conditions and over a long time in the heating season, a study was carried out using both experimental method and numerical method. The study was conducted in a typical greenhouse located in Beijing, China, and important parameters have been monitored continuously for 61 days, including indoor air temperature, outdoor air temperature, solar radiation, surface temperature of greenhouse envelopes and soil temperature. Based on these parameters, a number of indicators, namely, operative temperature, daily effective accumulative temperature, irradiated surface temperature of the north wall, average temperature of PCMs, and daily heat storage and release, have been used to evaluate the performance of PCMs in greenhouses. All indicators have provided consistent results that confirm the positive effect of PCMs on improving the indoor thermal environment of greenhouses over a long time. Additionally, the paper has demonstrated that a sunny weather could help to promote the efficiency of PCMs, comparing to a cloudy weather

  11. Performance evaluation of a three-phase dual active bridge DC-DC converter with different transformer winding configurations

    NARCIS (Netherlands)

    Baars, N.; Everts, J.; Wijnands, K.; Lomonova, E.

    2016-01-01

    This paper investigates the impact of three transformer winding configurations, i.e. the Y-Y, the Y-Delta, and the Delta-Delta configuration, on the performance of a three-phase dual active bridge (DAB) dc–dc converter. For each configuration, equations for the phase currents, power flow, and zero

  12. Effects of a School-Based Stress Prevention Programme on Adolescents in Different Phases of Behavioural Change

    Science.gov (United States)

    Vierhaus, Marc; Maass, Asja; Fridrici, Mirko; Lohaus, Arnold

    2010-01-01

    This study examines whether the assumptions of the Transtheoretical Model (TTM) are useful to evaluate the effectiveness of a school-based stress prevention programme in adolescence to promote appropriate coping behaviour. The TTM assumes three consecutive phases in the adoption of behavioural patterns. Progress throughout the phases is promoted…

  13. Fabricating eco-friendly nanocomposites of SiC with morphologically-different nano-carbonaceous phases 

    DEFF Research Database (Denmark)

    Candelario, Victor M.; Moreno, Rodrigo; Guiberteau, Fernando

    2018-01-01

    A route based on aqueous colloidal processing followed by liquid-phase assisted spark-plasma-sintering (SPS) is described for fabricating eco-friendly nanocomposites of SiC with nano-carbonaceous phases (nanotubes, nanoplatelets, or nanoparticles). To this end, the conditions optimizing the aqueo...

  14. Changes in hippocampal theta rhythm and their correlations with speed during different phases of voluntary wheel running in rats.

    Science.gov (United States)

    Li, J-Y; Kuo, T B J; Hsieh, I-T; Yang, C C H

    2012-06-28

    Hippocampal theta rhythm (4-12 Hz) can be observed during locomotor behavior, but findings on the relationship between locomotion speed and theta frequency are inconsistent if not contradictory. The inconsistency may be because of the difficulties that previous analyses and protocols have had excluding the effects of behavior training. We recorded the first or second voluntary wheel running each day, and assumed that theta frequency and activity are correlated with speed in different running phases. By simultaneously recording electroencephalography, physical activity, and wheel running speed, this experiment explored the theta oscillations during spontaneous running of the 12-h dark period. The recording was completely wireless and allowed the animal to run freely while being recorded in the wheel. Theta frequency and theta power of middle frequency were elevated before running and theta frequency, theta power of middle frequency, physical activity, and running speed maintained persistently high levels during running. The slopes of the theta frequency and theta activity (4-9.5 Hz) during the initial running were different compared to the same values during subsequent running. During the initial running, the running speed was positively correlated with theta frequency and with theta power of middle frequency. Over the 12-h dark period, the running speed did not positively correlate with theta frequency but was significantly correlated with theta power of middle frequency. Thus, theta frequency was associated with running speed only at the initiation of running. Furthermore, theta power of middle frequency was associated with speed and with physical activity during running when chronological order was not taken into consideration. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

  15. Effects of turbulence on mixed-phase deep convective clouds under different basic-state winds and aerosol concentrations

    Science.gov (United States)

    Lee, Hyunho; Baik, Jong-Jin; Han, Ji-Young

    2014-12-01

    The effects of turbulence-induced collision enhancement (TICE) on mixed-phase deep convective clouds are numerically investigated using a 2-D cloud model with bin microphysics for uniform and sheared basic-state wind profiles and different aerosol concentrations. Graupel particles account for the most of the cloud mass in all simulation cases. In the uniform basic-state wind cases, graupel particles with moderate sizes account for some of the total graupel mass in the cases with TICE, whereas graupel particles with large sizes account for almost all the total graupel mass in the cases without TICE. This is because the growth of ice crystals into small graupel particles is enhanced due to TICE. The changes in the size distributions of graupel particles due to TICE result in a decrease in the mass-averaged mean terminal velocity of graupel particles. Therefore, the downward flux of graupel mass, and thus the melting of graupel particles, is reduced due to TICE, leading to a decrease in the amount of surface precipitation. Moreover, under the low aerosol concentration, TICE increases the sublimation of ice particles, consequently playing a partial role in reducing the amount of surface precipitation. The effects of TICE are less pronounced in the sheared basic-state wind cases than in the uniform basic-state wind cases because the number of ice crystals is much smaller in the sheared basic-state wind cases than in the uniform basic-state wind cases. Thus, the size distributions of graupel particles in the cases with and without TICE show little difference.

  16. Use of solid phase microextraction to identify volatile organic compounds in brazilian wines from different grape varieties

    Directory of Open Access Journals (Sweden)

    Natália Cristina Morais Fernandes

    Full Text Available Abstract The Brazilian wine industry has shown significant growth in recent years and the insertion of new concepts, such as geographical indications as signs of quality, has placed Brazil in tune with the tendencies of world wine production. The aim of this work was to apply the Solid Phase Microextraction technique in combination with Gas Chromatography-Mass Spectrometry to study Brazilian wines made from different grape varieties, in order to separate and identify their volatile organic compounds. These substances were identified by comparisons between the spectra obtained with those presented in the NIST library database, and by comparisons with linear retention indices and literature data. The amounts of the compounds were calculated based on the total peak areas of the chromatograms. Forty-seven volatile compounds were identified and grouped into alcohols, aldehydes, fatty acids, esters, hydrocarbons, ketones and terpenes. Most of them belonged to the ester function, conferring a fruity aroma on the wines. The alcohols may have originated from the yeast metabolism, contributing to the alcoholic and floral aromas. Ethyl lactate, 1-hexanol and diethyl maleate were identified in all the varieties, except Merlot. Decanal, methyl citronellate, (E-2-hexenyl-3-methylbutyrate were only found in Merlot, while 2,3-butanediol was only present in the Tannat wines. 2-Phenylethanol was present in all varieties and is recognized as giving pleasant rose and honey attributes to wines. This study showed that the volatile profile of red wines is mainly characterized by esters and higher alcohols. The statistical analysis of the comparison of averages showed a greater amount of averages significantly different in the relative areas of Merlot wine. The Principal Component Analysis showed one grouping composed only of the Merlot wine samples, and this was probably related to the existence of the volatile organic compounds that were specifically identified in

  17. Assessment of antibacterial and cytotoxic effects of orthodontic stainless steel brackets coated with different phases of titanium oxide: An in-vitro study.

    Science.gov (United States)

    Baby, Roshen Daniel; Subramaniam, Siva; Arumugam, Ilakkiya; Padmanabhan, Sridevi

    2017-04-01

    Our objective was to assess the antibacterial and cytotoxic effects of orthodontic stainless steel brackets coated with different phases of photocatalytic titanium oxide. From a total sample of 115 brackets, 68 orthodontic stainless steel brackets were coated with titanium oxide using a radiofrequency magnetron sputtering machine. The coated brackets were then converted into 34 each of the anatase and rutile phases of titanium oxide. These brackets were subdivided into 4 groups for antibacterial study and 3 groups for cytotoxicity study. Brackets for the antibacterial study were assessed against the Streptococcus mutans species using microbiologic tests. Three groups for the cytotoxicity study were assessed using the thiazolyl tetrazolium bromide assay. The antibacterial study showed that both phases were effective, but the rutile phase of photocatalytic titanium oxide had a greater bactericidal effect than did the anatase phase. The cytotoxicity study showed that the rutile phase had a greater decrease in viability of cells compared with the anatase phase. It is recommended that orthodontic brackets be coated with the anatase phase of titanium oxide since they exhibited a significant antibacterial property and were only slightly cytotoxic. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  18. Optical path difference measurements with a two-step parallel phase shifting interferometer based on a modified Michelson configuration

    Science.gov (United States)

    Toto-Arellano, Noel Ivan; Serrano-Garcia, David I.; Rodriguez-Zurita, Gustavo

    2017-09-01

    We report an optical implementation of a parallel phase-shifting quasi-common path interferometer using two modified Michelson interferometers to generate two interferograms. By using a displaceable polarizer's array, placed on the image plane, we can obtain four phase-shifted interferograms in two captures. The system operates as a quasi-common path interferometer generating four beams, which are to interfere with alignment procedures on the mirrors of the Michelson configurations. The optical phase data are retrieved using the well-known four-step algorithms. To present the capabilities of the system, experimental results obtained from transparent structures are presented.

  19. Joint test rig for tests and calibration of different methods of two-phase mass flow measurement

    International Nuclear Information System (INIS)

    John, H.; Erbacher, F.; Wanner, E.

    1975-01-01

    On behalf of the Federal Ministry of Research and Technology, the Institute of Reactor Components (IRB) has begun building a test rig which will be used for testing and calibrating the methods of measuring non-steady state two-phase mass flows developed by various research agencies. The test rig is designed for the generation of steam-water mixtures of any mixing ratio and a maximum pressure of 160 data. Depending on the mixing ratio, the mass flow will reach a maximum level of 10 to 20 t/h. The conceptual design phase of the test rig has largely been finished, the component ordering phase has begun. (orig.) [de

  20. Effect of phase behavior, density, and isothermal compressibility on the constant-volume heat capacity of ethane + n-pentane mixed fluids in different phase regions

    International Nuclear Information System (INIS)

    Mu, Tiancheng; Liu, Zhimin; Han, Buxing.; Li, Zhonghao; Zhang, Jianling; Zhang, Xiaogang

    2003-01-01

    The phase behavior, density, and constant-volume molar heat capacity (C v,m ) of ethane + n-pentane binary mixtures have been measured in the supercritical region and subcritical region at T=309.45 K. In addition, the isothermal compressibility (κ T ) has been calculated using the density data determined. For a mixed fluid with a composition close to the critical composition, C v,m and κ T increase sharply as the pressure approaches the critical point (CP), the dew point (DP), or the bubble point (BP). However, C v,m is not sensitive to pressure in the entire pressure range if the composition of the mixed fluid is far from the critical composition. To tune the properties of the binary mixtures effectively by pressure, both the composition and the pressure should be close to the critical point of the mixture. The intermolecular interactions in the mixture are also discussed on the basis of the experimental results

  1. Hard-x-ray phase-difference microscopy with a low-brilliance laboratory x-ray source

    International Nuclear Information System (INIS)

    Kuwabara, Hiroaki; Yashiro, Wataru; Harasse, Sebastien; Momose, Atsushi; Mizutani, Haruo

    2011-01-01

    We have developed a hard-X-ray phase-imaging microscopy method using a low-brilliance X-ray source. The microscope consists of a sample, a Fresnel zone plate, a transmission grating, and a source grating creating an array of mutually incoherent X-ray sources. The microscope generates an image exhibiting twin features of the sample with opposite signs separated by a distance, which is processed to generate a phase image. The method is quantitative even for non-weak-phase objects that are difficult to be quantitatively examined by the widely used Zernike phase-contrast microscopy, and it has potentially broad applications in the material and biological science fields. (author)

  2. Analysis of genes that influence sheep follicular development by different nutrition levels during the luteal phase using expression profiling.

    Science.gov (United States)

    Luo, F; Jia, R; Ying, S; Wang, Z; Wang, F

    2016-06-01

    Nutrition is an important factor that regulates reproductive performance of sheep and affects follicle development. However, the correlation between nutrition and follicle development is poorly understood at the molecular level. To study its possible molecular mechanisms, we performed expression profiling of granulosa cells isolated from sheep that were fed different levels of nutrition levels during the luteal phase. To do this, ewes received a maintenance diet (M), and their estrus was synchronized by intravaginal progestogen sponges for 12 days. Ewes were randomly divided into the short-term dietary-restricted group (R; 0.5 × M) and the nutrient-supplemented group (S; 1.5 × M). RNA samples were extracted from granulosa cells. Transcriptome libraries from each group were constructed by Illumina sequencing. Among 18 468 detected genes, 170 genes were significantly differentially expressed, of which 140 genes were upregulated and 30 genes were downregulated in group S relative to group R. These genes could be candidates regulating follicular development in sheep. Gene Ontology, KEGG and clustering analyses were performed. Genes related to oocyte meiosis, such as ADCY7, were upregulated. We identified two important groups of related genes that were upregulated with improved nutrition: one group comprising the genes PTGS2, UCP2 and steroidogenic acute regulatory protein and the other group comprising interleukin-1A and interleukin-1B. The genes within each group showed similar expression patterns. Additionally, all five genes are involved in the reproduction process. Quantitative real-time PCR was performed to validate the results of expression profiling. These data in our study are an abundant genomic resource to expand the understanding of the molecular and cellular events underlying follicle development. © 2016 Stichting International Foundation for Animal Genetics.

  3. Extraction and height estimation of artificial vertical structures based on the wrapped interferometric phase difference within their layovers

    Science.gov (United States)

    Uemoto, Jyunpei; Nadai, Akitsugu; Kojima, Shoichiro; Kobayashi, Tatsuharu; Umehara, Toshihiko; Matsuoka, Takeshi; Uratsuka, Seiho; Satake, Makoto

    2018-05-01

    The geometric modulation of synthetic aperture radar (SAR) imagery such as radar shadow, foreshortening, and layover often complicates image interpretation while it contains useful information about targets. Recently, some methods for automatic building detection utilizing a peculiar pattern of phase differences (PDs) within building layovers on SAR interferograms have been proposed. One of the merits of these methods is the capability to detect buildings even taller than the height of ambiguity without incorporating any external data. In this paper, we propose a new method that has achieved the following improvements while maintaining the merit mentioned above. The first improvement is freedom from the dependence of target heights; without changing any parameters and thresholds, the proposed method can detect low-rise apartments to skyscrapers. The second one is the prevention of the false grouping of vertical structure constituents by considering relationships between their PDs. In addition, the method can measure the height of vertical structures without assuming their shape to be simple ones such as a parallelogram. These improvements have been verified by applying the method to real datasets acquired from an airborne X-band SAR. The quantitative assessment for apartment complexes has demonstrated the high performance of the method; the correctness and completeness are 94% and 83%, respectively. The mean error in the measured height is -0.2 m, while the standard deviation is 1.8 m. The verification using real datasets has revealed at the same time that the performance of the method can be degraded due to the crowdedness in dense urban areas including skyscrapers and owing to the poor discriminability between artificial vertical structures and trees. Overcoming these limitations is necessary in future studies.

  4. Solid-phase microextraction of phthalate esters in water sample using different activated carbon-polymer monoliths as adsorbents.

    Science.gov (United States)

    Lirio, Stephen; Fu, Chung-Wei; Lin, Jhih-Yun; Hsu, Meng-Ju; Huang, Hsi-Ya

    2016-07-13

    In this study, the application of different activated carbon-polymer (AC-polymer) monoliths as adsorbents for the solid-phase microextraction (SPME) of phthalate esters (PAEs) in water sample were investigated. The activated carbon (AC) was embedded in organic polymers, poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-EDMA)) or poly(styrene-co-divinylbenzene) (poly(STY-DVB)), via a 5-min microwave-assisted or a 15-min water bath heating polymerization. Preliminary investigation on the performance of the native poly(BMA-EDMA) and poly(STY-DVB) demonstrated remarkable adsorption efficiencies for PAEs. However, due to the strong hydrophobic, π-π, and hydrogen bonding interactions between the analytes and polymers, low extraction recoveries were achieved. In contrast, the presence of AC in native polymers not only enhanced the adsorption efficiencies but also assisted the PAE desorption, especially for AC-poly(STY-DVB) with extraction recovery ranged of 76.2-99.3%. Under the optimized conditions, the extraction recoveries for intra-, inter-day and column-to-column were in the range of 76.5-100.8% (<3.7% RSDs), 77.2-97.6% (<5.6% RSDs) and 75.5-99.7% (<6.2% RSDs), respectively. The developed AC-poly(STY-DVB) monolithic column showed good mechanical stability, which can be reused for more than 30 extraction times without any significant loss in the extraction recoveries of PAEs. The AC-poly(STY-DVB) monolithic column was successfully applied in SPME of PAEs in water sample with extraction recovery ranged of 78.8%-104.6% (<5.5% RSDs). Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Assessment of the effects of different sample perfusion procedures on phase-contrast tomographic images of mouse spinal cord

    Science.gov (United States)

    Stefanutti, E.; Sierra, A.; Miocchi, P.; Massimi, L.; Brun, F.; Maugeri, L.; Bukreeva, I.; Nurmi, A.; Begani Provinciali, G.; Tromba, G.; Gröhn, O.; Giove, F.; Cedola, A.; Fratini, M.

    2018-03-01

    Synchrotron X-ray Phase Contrast micro-Tomography (SXrPCμT) is a powerful tool in the investigation of biological tissues, including the central nervous system (CNS), and it allows to simultaneously detect the vascular and neuronal network avoiding contrast agents or destructive sample preparations. However, specific sample preparation procedures aimed to optimize the achievable contrast- and signal-to-noise ratio (CNR and SNR, respectively) are required. Here we report and discuss the effects of perfusion with two different fixative agents (ethanol and paraformaldehyde) and with a widely used contrast medium (MICROFIL®) on mouse spinal cord. As a main result, we found that ethanol enhances contrast at the grey/white matter interface and increases the contrast in correspondence of vascular features and fibres, thus providing an adequate spatial resolution to visualise the vascular network at the microscale. On the other hand, ethanol is known to induce tissue dehydration, likely reducing cell dimensions below the spatial resolution limit imposed by the experimental technique. Nonetheless, neurons remain well visible using either perfused paraformaldehyde or MICROFIL® compound, as these latter media do not affect tissues with dehydration effects. Paraformaldehyde appears as the best compromise: it is not a contrast agent, like MICROFIL®, but it is less invasive than ethanol and permits to visualise well both cells and blood vessels. However, a quantitative estimation of the relative grey matter volume of each sample has led us to conclude that no significant alterations in the grey matter extension compared to the white matter occur as a consequence of the perfusion procedures tested in this study.

  6. Assessment of myeloperoxidase activity at different force levels in gingival crevicular fluid during initial phase of orthodontic tooth movement

    Directory of Open Access Journals (Sweden)

    Honey Gurbaxani

    2017-01-01

    Full Text Available Background: Orthodontic movements promote remodeling of the alveolar bone, which is mediated by inflammatory reactions such as characterized by vascular changes and infiltration of leukocytes. Changes in the periodontium occur, depending on the magnitude, duration, and direction of applied force. These changes are often seen in the saliva and gingival fluids through the various substances secreted in them. Aim: The present study aimed to assess myeloperoxidase (MPO activity at different force levels in gingival crevicular fluid (GCF during the initial phase of orthodontic tooth movement by varying the effective force levels to 50, 75, 100, and 150 g. Materials and Methods: A total of thirty participants between the age groups of 18–25 years requiring upper first premolar extractions were included in the study. They were divided into three groups (I, II, and III of ten individuals each, again subdivided into two Subgroups A and B depending on the amount of force applied to the canine. Subgroup A of all the three groups used 150 g, whereas Subgroup B used 50, 75, and 100 g of force, respectively. GCF was collected at 2 h, 7 days, and 14 days of force application. Statistical Analysis: Paired t-test and ANOVA test were used to provide the descriptive statistics of mean optical density to detect the presence of MPO in GCF. Results and Conclusion: There was a highly significant increase in the MPO levels in the GCF at 14th day after force application which can be correlated to the onset of inflammatory reactions in the periodontium.

  7. Synthesis and luminescent properties of two different Y{sub 2}WO{sub 6}:Eu{sup 3+} phosphor phases

    Energy Technology Data Exchange (ETDEWEB)

    Llanos, Jaime, E-mail: jllanos@ucn.cl [Departamento de Química, Universidad Católica del Norte, Avda. Angamos 0610, Antofagasta (Chile); Olivares, Douglas [Departamento de Química, Universidad Católica del Norte, Avda. Angamos 0610, Antofagasta (Chile); Manríquez, Víctor; Espinoza, Darío [Departamento de Química, Universidad de Chile, Las Palmeras 3425, Santiago (Chile); Brito, Ivan [Departamento de Química, Universidad de Antofagasta, Campus Coloso, Antofagasta (Chile)

    2015-04-15

    Highlights: • Synthesis of two phases Y{sub 2−x}Eu{sub x}WO{sub 6}. One of them crystallizes as Aurivillius phase. • Optical properties of the phosphors Y{sub 2}WO{sub 6}:Eu{sup 3+} (monoclinic and orthorhombic phases). • The orthorhombic phase was prepared via low-temperature combustion synthesis method. - Abstract: In this paper, two different Y{sub 2−x}Eu{sub x}WO{sub 6} phases were synthesized. The monoclinic phase was prepared via a conventional solid-state reaction, whereas the orthorhombic phase was obtained via a facile, low-temperature combustion synthesis method. X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and photoluminescence (PL) spectroscopy were used to characterize the resulting phosphors. The XRD results indicate the orthorhombic phase crystallized isostructurally with the Aurivillius Bi{sub 2}WO{sub 6} phase, whereas the other polymorph crystallized isostructurally with Yb{sub 2}WO{sub 6} in the monoclinic system. The SEM studies revealed both phases had a strong tendency to form agglomerates averaging nanometers in size. The photoluminescence emission spectra confirmed all of the samples were efficiently excited by near UV light and were dominated by the electric dipole transition {sup 5}D{sub 0} → {sup 7}F{sub 2}. The orthorhombic Y{sub 2−x}Eu{sub x}WO{sub 6} excitation spectrum possessed a broad band across the entire UV region (220–400 nm); therefore, Y{sub 1.86}Eu{sub 0.14}WO{sub 6} could be considered an efficient spectral converter material for use in dye-sensitized solar cells.

  8. Studies on phase transformation and molecular orientation in nanostructured zinc phthalocyanine thin films annealed at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Avijit; Biswas, Bipul; Majumder, Manisree; Sanyal, Manik Kumar; Mallik, Biswanath, E-mail: spbm@iacs.res.in

    2012-08-31

    Studies on the electronic and optical properties of thin films of organometallic compounds such as phthalocyanine are very important for the development of devices based on these compounds. The nucleation and grain growth mechanism play an important role for the final electronic as well as optoelectronic properties of the organic and organometallic thin films. The present article deals with the change in the film morphology, grain orientation of nanocrystallites and optical properties of zinc phthalocyanines (ZnPc) thin films as a function of the post deposition annealing temperature. The effect of annealing temperature on the optical and structural property of vacuum evaporated ZnPc thin films deposited at room temperature (30 Degree-Sign C) on quartz glass and Si(100) substrates has been investigated. The thin films have been characterized by the UV-vis optical absorption spectra, X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy. From the studies of UV-vis absorption spectra and XRD data, a metastable {alpha} to {beta}-phase transformation has been observed when the thin films were annealed at a temperature greater than about 250 Degree-Sign C. The FESEM images have shown the particlelike structure at room temperature and the structure became rodlike when the films were annealed at high temperatures. TEM image of ZnPc film dissolved in ethanol has shown spectacular rod-shaped crystallites. High resolution transmission electron microscopy image of a single nanorod has shown beautiful 'honey-comb' like structure. Particle size and root mean square roughness were calculated from AFM images. The changes in band gap energy with increase in annealing temperature have been evaluated. - Highlights: Black-Right-Pointing-Pointer Morphology and orientation of grains in zinc phthalocyanine (ZnPc) thin films. Black

  9. There are differences in cerebral activation between females in distinct menstrual phases during viewing of erotic stimuli: A fMRI study.

    Science.gov (United States)

    Gizewski, Elke R; Krause, Eva; Karama, Sherif; Baars, Anneke; Senf, Wolfgang; Forsting, Michael

    2006-09-01

    There is evidence that men experience more sexual arousal than women but also that women in mid-luteal phase experience more sexual arousal than women outside this phase. Recently, a few functional brain imaging studies have tackled the issue of gender differences as pertaining to reactions to erotica. The question of whether or not gender differences in reactions to erotica are maintained with women in different phases has not yet been answered from a functional brain imaging perspective. In order to examine this issue, functional MRI was performed in 22 male and 22 female volunteers. Subjects viewed erotic film excerpts alternating with emotionally neutral excerpts in a standard block-design paradigm. Arousal to erotic stimuli was evaluated using standard rating scales after scanning. Two-sample t-test with uncorrected P erotic stimuli and with corrected P erotic stimuli. Furthermore, gender differences with women in mid-luteal phases are similar to those in females outside the mid-luteal phase.

  10. Changes of optical, dielectric, and structural properties of Si15Sb85 phase change memory thin films under different initializing laser power

    International Nuclear Information System (INIS)

    Huang Huan; Zhang Lei; Wang Yang; Han Xiaodong; Wu Yiqun; Zhang Ze; Gan Fuxi

    2011-01-01

    Research highlights: → We study the optical, dielectric, and structural characteristics of Si 15 Sb 85 phase change memory thin films under a moving continuous-wave laser initialization. → The optical and dielectric constants, absorption coefficient of Si 15 Sb 85 change regularly with the increasing laser power. → The optical band gaps of Si 15 Sb 85 irradiated upon different power lasers were calculated. → HRTEM images of the samples were observed and the changes of optical and dielectric constants are determined by crystalline structures changes of the films. - Abstract: The optical, dielectric, and structural characteristics of Si 15 Sb 85 phase change memory thin films under a moving continuous-wave laser initialization are studied by using spectroscopic ellipsometry and high-resolution transmission electron microscopy. The dependence of complex refractive index, dielectric functions, absorption coefficient, and optical band gap of the films on its crystallization extents formed by the different initialization laser power are analyzed in detail. The structural change from as-deposited amorphous phase to distorted rhombohedra-Sb-like crystalline structure with the increase of initialization laser power is clearly observed with sub-nanometer resolution. The optical and dielectric constants, the relationship between them, and the local atomic arrangements of this new phase change material can help explain the phase change mechanism and design the practical phase change memory devices.

  11. Phase diagrams and radial distribution of the electric field components of coaxial discharges with outer dielectric tube at different wave modes

    International Nuclear Information System (INIS)

    Neichev, Z; Benova, E; Gamero, A; Sola, A

    2007-01-01

    The purpose of this work is to investigate phase diagrams and electric field radial distribution of coaxial discharges, sustained by a traveling electromagnetic wave, assuming finite and infinite thickness of the discharge chamber in the model. The calculations are made for azimuthally symmetric and dipolar wave modes. The phase diagrams and the radial profiles of the electric field at various thicknesses of the outer dielectric tube of the chamber and different discharge conditions are obtained. For the purpose of low pressure coaxial plasma modelling, radial profiles of the electric field at different discharge conditions have been investigated experimentally and compared with the theoretical results

  12. Vapor-deposited non-crystalline phase vs ordinary glasses and supercooled liquids: Subtle thermodynamic and kinetic differences

    International Nuclear Information System (INIS)

    Bhattacharya, Deepanjan; Sadtchenko, Vlad

    2015-01-01

    Vapor deposition of molecules on a substrate often results in glassy materials of high kinetic stability and low enthalpy. The extraordinary properties of such glasses are attributed to high rates of surface diffusion during sample deposition, which makes it possible for constituents to find a configuration of much lower energy on a typical laboratory time scale. However, the exact nature of the resulting phase and the mechanism of its formation are not completely understood. Using fast scanning calorimetry technique, we show that out-of-equilibrium relaxation kinetics and possibly the enthalpy of vapor-deposited films of toluene and ethylbenzene, archetypical fragile glass formers, are distinct from those of ordinary supercooled phase even when the deposition takes place at temperatures above the ordinary glass softening transition temperatures. These observations along with the absolute enthalpy dependences on deposition temperatures support the conjecture that the vapor-deposition may result in formation of non-crystalline phase of unique structural, thermodynamic, and kinetic properties

  13. A measurement of the phase difference of $\\eta_{00}$ and $\\eta_{+-}$ in CP violating $K^{0}$ $\\rightarrow$ 2$\\pi$ decays

    CERN Multimedia

    2002-01-01

    CP violation is well established in the $K^{0}\\overline{ K}^{0}$ system. In the phenomenology of $K^{0}$-decay the phase of the ratio of decay amplitudes $\\eta$ of CP conserving and CP violating two pion decays is given by CPT and unitarity to be 'arc tan' 1/2 $\\Gamma_{S}$ / $(M_{L}-M_{S}) = 43.7 \\pm 0.2^{\\circ}$. It is the purpose of this experiment to test the equality of this phase for the decay into neutral and charged pions, respectively. The phase of $\\eta$ is determined from the time-dependence of the rate of kaon decays into two pions, using the NA31 detector in a modified beam with $K_{S}$ and $K_{L}$ in interference.

  14. Lattice Boltzmann modeling of contact angle and its hysteresis in two-phase flow with large viscosity difference.

    Science.gov (United States)

    Liu, Haihu; Ju, Yaping; Wang, Ningning; Xi, Guang; Zhang, Yonghao

    2015-09-01

    Contact angle hysteresis is an important physical phenomenon omnipresent in nature and various industrial processes, but its effects are not considered in many existing multiphase flow simulations due to modeling complexity. In this work, a multiphase lattice Boltzmann method (LBM) is developed to simulate the contact-line dynamics with consideration of the contact angle hysteresis for a broad range of kinematic viscosity ratios. In this method, the immiscible two-phase flow is described by a color-fluid model, in which the multiple-relaxation-time collision operator is adopted to increase numerical stability and suppress unphysical spurious currents at the contact line. The contact angle hysteresis is introduced using the strategy proposed by Ding and Spelt [Ding and Spelt, J. Fluid Mech. 599, 341 (2008)JFLSA70022-112010.1017/S0022112008000190], and the geometrical wetting boundary condition is enforced to obtain the desired contact angle. This method is first validated by simulations of static contact angle and dynamic capillary intrusion process on ideal (smooth) surfaces. It is then used to simulate the dynamic behavior of a droplet on a nonideal (inhomogeneous) surface subject to a simple shear flow. When the droplet remains pinned on the surface due to hysteresis, the steady interface shapes of the droplet quantitatively agree well with the previous numerical results. Four typical motion modes of contact points, as observed in a recent study, are qualitatively reproduced with varying advancing and receding contact angles. The viscosity ratio is found to have a notable impact on the droplet deformation, breakup, and hysteresis behavior. Finally, this method is extended to simulate the droplet breakup in a microfluidic T junction, with one half of the wall surface ideal and the other half nonideal. Due to the contact angle hysteresis, the droplet asymmetrically breaks up into two daughter droplets with the smaller one in the nonideal branch channel, and the

  15. A Time Difference Method for Measurement of Phase Shift between Distributed Feedback Laser Diode (DFB-LD Output Wavelength and Intensity

    Directory of Open Access Journals (Sweden)

    Yongning Liu

    2015-07-01

    Full Text Available A time difference method to conveniently measure the phase shift between output wavelength and intensity of distributed feedback laser diodes (DFB-LDs was proposed. This approach takes advantage of asymmetric absorption positions at the same wavelength during wavelength increase and decrease tuning processes in the intensity-time curve by current modulation. For its practical implementation, a measurement example of phase shift was demonstrated by measuring a time difference between the first time and the second time attendances of the same gas absorption line in the intensity-time curve during one sine or triangle modulation circle. The phase shifts at modulation frequencies ranging from 50 Hz to 50 kHz were measured with a resolution of 0.001π. As the modulation frequency increased the shift value increased with a slowed growth rate.

  16. Characteristics and stability analyses of transient one-dimensional two-phase flow equations and their finite difference approximations

    International Nuclear Information System (INIS)

    Lyczkowski, R.W.; Gidaspow, D.; Solbrig, C.W.; Hughes, E.D.

    1975-01-01

    Equation systems describing one-dimensional, transient, two-phase flow with separate continuity, momentum, and energy equations for each phase are classified by use of the method of characteristics. Little attempt is made to justify the physics of these equations. Many of the equation systems possess complex-valued characteristics and hence, according to well-known mathematical theorems, are not well-posed as initial-value problems (IVPs). Real-valued characteristics are necessary but not sufficient to insure well-posedness. In the absence of lower order source or sink terms (potential type flows), which can affect the well-posedness of IVPs, the complex characteristics associated with these two-phase flow equations imply unbounded exponential growth for disturbances of all wavelengths. Analytical and numerical examples show that the ill-posedness of IVPs for the two-phase flow partial differential equations which possess complex characteristics produce unstable numerical schemes. These unstable numerical schemes can produce apparently stable and even accurate results if the growth rate resulting from the complex characteristics remains small throughout the time span of the numerical experiment or if sufficient numerical damping is present for the increment size used. Other examples show that clearly nonphysical numerical instabilities resulting from the complex characteristics can be produced. These latter types of numerical instabilities are shown to be removed by the addition of physically motivated differential terms which eliminate the complex characteristics. (auth)

  17. Identification of regioisomers and enantiomers of triacylglycerols in different yeasts using reversed- and chiral-phase LC–MS

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Kolouchová, I.; Čejková, A.; Cajthaml, Tomáš; Sigler, Karel

    2013-01-01

    Roč. 36, č. 20 (2013), s. 3310-3320 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 Keywords : Atmospheric pressure chemical ionization mass spectrometry * Chiral LC * Reversed phase LC Subject RIV: EE - Microbiology, Virology Impact factor: 2.594, year: 2013

  18. Visualization and measurement of gas-liquid metal two-phase flow with large density difference using thermal neutrons as microscopic probes

    International Nuclear Information System (INIS)

    Mishima, K.; Hibiki, T.; Saito, Y.; Nishihara, H.; Tobita, Y.; Konishi, K.; Matsubayashi, M.

    1999-01-01

    In a core melt accident of a fast breeder reactor, there is a possibility of boiling of the fuel-steel mixture in the containment pool. In relation to safety evaluation on severe accident, it is indispensable to evaluate the possibility of re-criticality of melted core. Gas-liquid two-phase flow with a large liquid-to-gas density ratio is formed due to the boiling of fuel-steel mixture. Although it is anticipated that the large density ratio may affect the basic characteristics of two-phase flow, little work has been performed so far on two-phase flow with a large liquid-to-gas density ratio. In this study, visualization and void fraction measurement of gas-liquid metal two-phase flow were performed by using neutron radiography and image processing techniques. Then, the effect of large density difference between gas and liquid phases on the basic flow characteristics of two-phase flow was clarified

  19. Analysis of the functional state of students in the process of healthy training exercises in different phases of the ovarian-menstrual cycle

    Directory of Open Access Journals (Sweden)

    N.V. Petrenko

    2017-11-01

    Full Text Available Aim: to substantiate the application of a rational program of health-training sessions in the educational process of physical education of students in different phases of the ovarian-menstrual cycle. Material: in study participated students (n=127, who did not have deviations in health (the main medical group. According to the results of the tests were determined: heart rate; blood pressure; vital capacity of the lungs. To determine physical performance was used Harvard step-test. Physical exercises from the main means of health fitness were used differentially and dosed. Results: It was established that the consideration in the phases of the ovarian-menstrual cycle of indicators of the functional state, changes in well-being and working capacity give an opportunity: planning loads in the training process; adjustment of volume and intensity of loads. We recommend to schedule the load of our program as follows: in the menstrual phase - the development of flexibility (moderate load; in the postmenstrual phase - development of coordination, overall endurance; in ovulatory - speed development; in postovulatory - development of special endurance; in premenstrual - the development of strength, flexibility. In the postmenstrual and postovulatory phase, a high level of physical working capacity, functional state of the cardiopulmonary system has been registered. It also has a positive effect on body weight correction in the women students. Conclusions: When developing programs of health training sessions with women students it is necessary to take into account the phases of the ovarian-menstrual cycle.

  20. Methane content and potential of biogas' production by manure of pigs fed with corn or sorghum-based diets in different phases

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Adelia Pereira; Lucas Junior, Jorge de; Thomaz, Maria Cristina; Fukayama, Ellen Hatsumi [Universidade Estadual Paulista (UNESP), Jaboticabal, SP (Brazil)

    2008-07-01

    The aim of this trial was to value the methane content and potential of biogas' production by manure of pigs fed with corn or sorghum-based diets (energy's source) in different phases. The manures were daily collected, diluted in water and homogeneous. Were used 267 mL of influent with 6% total solids concentration for supply of continuous-flow laboratory anaerobic digesters, with 30 days of detention time (DT) and temperature of 35 deg C. The experiment was completely randomized design with 2 treatments (corn or sorghum) and 3 phases of growth (initial x growing x finishing) in 10 replications (anaerobic digesters). The methane contents by manure of pigs fed with corn were greater (p<0.01) than pigs fed with sorghum (65.19 and 67.32%) on the phases of growing and finishing, respectively. The most potential of biogas' production (0.181, 0.138 and 0.162 m{sup 3}/kg of manure) was with manure of pigs fed with corn on the phases of initial, growing and finishing, respectively (p<0.01). Considering all the phases, the most potential of biogas' production (p<0.01) was observed in the initial phase, in both treatments. (author)

  1. Safety and immunogenicity of three different formulations of an adjuvanted varicella-zoster virus subunit candidate vaccine in older adults: a phase II, randomized, controlled study

    NARCIS (Netherlands)

    Chlibek, Roman; Smetana, Jan; Pauksens, Karlis; Rombo, Lars; van den Hoek, J. Anneke R.; Richardus, Jan H.; Plassmann, Georg; Schwarz, Tino F.; Ledent, Edouard; Heineman, Thomas C.

    2014-01-01

    This study investigated the safety and immunogenicity of different formulations and schedules of a candidate subunit herpes zoster vaccine containing varicella-zoster virus glycoprotein E (gE) with or without the adjuvant system AS01B. In this phase II, single-blind, randomized, controlled study,

  2. Behavioural change phases of different stakeholders involved in the implementation process of ergonomics measures in bricklaying (vol 36, pg 449, 2005)

    NARCIS (Netherlands)

    van der Molen, H. F.; Sluiter, J. K.; Frings-Dresen, M. H. W.

    2005-01-01

    The objective of this qualitative study was to assess whether a hypothesised sequential order of behavioural change phases would be fulfilled in different groups of stakeholders involved at the start of a process to implement ergonomic measures in bricklaying teams. The measures include trestles,

  3. Characterization of Microstructure and Mechanical Properties of Mg-Y-Zn Alloys with Respect to Different Content of LPSO Phase

    Czech Academy of Sciences Publication Activity Database

    Horváth, Klaudia; Drozdenko, D.; Daniš, S.; Garces, G.; Máthis, K.; Kim, S.; Dobroň, P.

    2018-01-01

    Roč. 20, č. 1 (2018), č. článku 1700396. ISSN 1438-1656 R&D Projects: GA MŠk EF16_013/0001794 Institutional support: RVO:61389005 Keywords : acoustic emission * alloying elements * LPSO phase * magnesium alloys * mechanical properties Subject RIV: JJ - Other Materials OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.319, year: 2016

  4. The expansive phase of magnetospheric substorms 2. The response at synchronous altitude of particles of different energy ranges

    International Nuclear Information System (INIS)

    Rostoker, G.; Kisabeth, J.L.; Sharp, R.D.; Shelley, E.G.

    1975-01-01

    Several previous studies have shown that there are variations in the energetic particle populations at synchronous orbit during periods of substorm activity; however, in these investigations the precise location of the satellite with respect to the longitudinal regime experiencing expansion phase activity has been unknown. In this paper, data from the Lockheed particle detectors on ATS 5 in synchronous orbit and from the meridian line of magnetometers operated by the University of Alberta are correlated for periods of substorm activity where the position of the satellite with respect to the expansion phase regime is known. It is found that changes in the nature of the energetic particle signatures at ATS 5 are correlated with changes in the auroral electrojet structure during the development of the substorm expansive phase. In particular, it is found that marked increases in the fluxes of the energetic particles showing no dispersion among the energy channels occur only when the satellite is on field lines which map to the poleward border of the substorm-intensified westward electrojet. It is further found that when the satellite is on field lines which penetrate the heart of the substorm westward electrojet, one only observes steady high fluxes of energetic particles, and there are no sharp well-defined changes in fluxes associated with continuing impulsive intensifications of the electrojet at its poleward border. It is concluded that the substorm disturbance typically begins at a given latitude and propagates poleward steps and that energetic electron enhancements are observed at ATS 5 when the poleward border of the electrojet intensifies in the latitude range of the ATS field line foot. This fact permits the mapping of field lines in the geographic equatorial plane to the earth's surface at specific instants during the substorm expansion phase

  5. Liquid-liquid phase separation and solidification behavior of Al55Bi36Cu9 monotectic alloy with different cooling rates

    Science.gov (United States)

    Bo, Lin; Li, Shanshan; Wang, Lin; Wu, Di; Zuo, Min; Zhao, Degang

    2018-03-01

    The cooling rate has a significant effect on the solidification behavior and microstructure of monotectic alloy. In this study, different cooling rate was designed through casting in the copper mold with different bore diameters. The effects of different cooling rate on the solidification behavior of Al55Bi36Cu9 (at.%) immiscible alloy have been investigated. The liquid-liquid phase separation of Al55Bi36Cu9 immiscible alloy melt was investigated by resistivity test. The solidification microstructure and phase analysis of Al55Bi36Cu9 immiscible alloy were performed by the SEM and XRD, respectively. The results showed that the liquid-liquid phase separation occurred in the solidification of Al55Bi36Cu9 monotectic melt from 917 °C to 653 °C. The monotectic temperature, liquid phase separation temperature and immiscibility zone of Al55Bi36Cu9 monotectic alloy was lower than those of Al-Bi binary monotectic alloy. The solidification morphology of Al55Bi36Cu9 monotectic alloy was very sensitive to the cooling rate. The Al/Bi core-shell structure formed when Al55Bi36Cu9 melt was cast in the copper mold with a 8 mm bore diameter.

  6. Investigation of Ionospheric Anomalies related to moderate Romanian earthquakes occurred during last decade using VLF/LF INFREP and GNSS Global Networks

    Science.gov (United States)

    Moldovan, Iren-Adelina; Oikonomou, Christina; Haralambous, Haris; Nastase, Eduard; Emilian Toader, Victorin; Biagi, Pier Francesco; Colella, Roberto; Toma-Danila, Dragos

    2017-04-01

    Ionospheric TEC (Total Electron Content) variations and Low Frequency (LF) signal amplitude data prior to five moderate earthquakes (Mw≥5) occurred in Romania, in Vrancea crustal and subcrustal seismic zones, during the last decade were analyzed using observations from the Global Navigation Satellite System (GNSS) and the European INFREP (International Network for Frontier Research on Earthquake Precursors) networks respectively, aiming to detect potential ionospheric anomalies related to these events and describe their characteristics. For this, spectral analysis on TEC data and terminator time method on VLF/LF data were applied. It was found that TEC perturbations appeared few days (1-7) up to few hours before the events lasting around 2-3 hours, with periods 20 and 3-5 minutes which could be associated with the impending earthquakes. In addition, in all three events the sunrise terminator times were delayed approximately 20-40 min few days prior and during the earthquake day. Acknowledgments This work was partially supported by the Partnership in Priority Areas Program - PNII, under MEN-UEFISCDI, DARING Project no. 69/2014 and the Nucleu Program - PN 16-35, Project no. 03 01

  7. Influence of bodybuilding training on changes in the anthropometric indicators of skilled female athletes in different phases of a specific biological cycle

    Directory of Open Access Journals (Sweden)

    Yevheniia Dzhym

    2017-08-01

    Full Text Available Purpose: to carry out research on the influence of the activities of female athletes engaged in bodybuilding on changes in anthropometric indicators in different phases of the ovarian-menstrual cycle (OMC. Material & Methods: studies were conducted in the fitness clubs of Kharkiv "Pheromone", "City", "King" with qualified athletes who are engaged in bodybuilding for 3 months of the preparatory period in the amount of 22 people. As research methods used: analysis of literature sources and testing of the level of motor qualities in individual phases of the OMC. Result: presented analysis of the condition of the female athletes taking into account the features of the OMC phases and the testing of body weight and anthropometric indicators in different phases of a specific biological cycle in qualified female athletes engaged in bodybuilding. Conclusion: Obtained results indicate that the anthropometric indicators of qualified female athletes engaged in bodybuilding are not the same in the phases of the ovarian-menstrual cycle. It was revealed that during the OMC period the body is able to retain water, which leads to fluctuations in the body weight of female athletes from 0,5 to 2,5 kg, while on the 3rd-6th day and on the 25–26th there is an increase in body weight, and on the 7th and 16th - its decrease. According to the results of the study, in the first phase, the decrease in anthropometry and body weight, this is due to the rejection of the mucous membrane of the uterus and menstrual bleeding.

  8. Precipitation phases at different processes and heat treat ments as well as their effects on the mechanical properties of super-austenitic stainless steel

    Science.gov (United States)

    Sun, Hunying; Zhou, Zhangjian; Wang, Man; Li, Shaofu; Zhang, Liwei; Zou, Lei

    2013-03-01

    A new type lCr30Ni30Mo2TiZr super-austenitic stainless steel has been developed. The microstructures, precipitation phases and mechanical properties of the steel under different deformation processes and heat treatment (solution, stabilized treatment) were investigated using X-ray Diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) as well as mechanical tests. The results indicate that coarse carbides such as Cr-rich M23C6, sigma (σ), and little chi (χ) phases were formed in the steel, and large α' -Cr phases were also detected at three joint grain boundaries, and they were promoted by large strain. The precipitate phases were dissolved or transformed to intermetallic phase even at higher elevated temperature, and influenced the mechanical property obviously. These intermetallic compounds seriously reduced elongation of the rolled steel at room temperature and 700 °C, but increased the forged one at 700 °C. Impact absorbed energies of the stabilized specimens were lower than half of that solution status.

  9. One-pot synthesis of CuInS2 nanocrystals using different anions to engineer their morphology and crystal phase.

    Science.gov (United States)

    Tang, Aiwei; Hu, Zunlan; Yin, Zhe; Ye, Haihang; Yang, Chunhe; Teng, Feng

    2015-05-21

    A simple one-pot colloidal method has been described to engineer ternary CuInS2 nanocrystals with different crystal phases and morphologies, in which dodecanethiol is chosen as the sulfur source and the capping ligands. By a careful choice of the anions in the metal precursors and manipulation of the reaction conditions including the reactant molar ratios and the reaction temperature, CuInS2 nanocrystals with chalcopyrite, zincblende and wurtzite phases have been successfully synthesized. The type of anion in the metal precursors has been found to be essential for determining the crystal phase and morphology of the as-obtained CuInS2 nanocrystals. In particular, the presence of Cl(-) ions plays an important role in the formation of CuInS2 nanoplates with a wurtzite-zincblende polytypism structure. In addition, the molar ratios of Cu to In precursors have a significant effect on the crystal phase and morphology, and the intermediate Cu2S-CuInS2 heteronanostructures are formed which are critical for the anisotropic growth of CuInS2 nanocrystals. Furthermore, the optical absorption results of the as-obtained CuInS2 nanocrystals exhibit a strong dependence on the crystal phase and size.

  10. Changes in the Milk Metabolome of the Giant Panda (Ailuropoda melanoleuca) with Time after Birth--Three Phases in Early Lactation and Progressive Individual Differences.

    Science.gov (United States)

    Zhang, Tong; Zhang, Rong; Zhang, Liang; Zhang, Zhihe; Hou, Rong; Wang, Hairui; Loeffler, I Kati; Watson, David G; Kennedy, Malcolm W

    2015-01-01

    Ursids (bears) in general, and giant pandas in particular, are highly altricial at birth. The components of bear milks and their changes with time may be uniquely adapted to nourish relatively immature neonates, protect them from pathogens, and support the maturation of neonatal digestive physiology. Serial milk samples collected from three giant pandas in early lactation were subjected to untargeted metabolite profiling and multivariate analysis. Changes in milk metabolites with time after birth were analysed by Principal Component Analysis, Hierarchical Cluster Analysis and further supported by Orthogonal Partial Least Square-Discriminant Analysis, revealing three phases of milk maturation: days 1-6 (Phase 1), days 7-20 (Phase 2), and beyond day 20 (Phase 3). While the compositions of Phase 1 milks were essentially indistinguishable among individuals, divergences emerged during the second week of lactation. OPLS regression analysis positioned against the growth rate of one cub tentatively inferred a correlation with changes in the abundance of a trisaccharide, isoglobotriose, previously observed to be a major oligosaccharide in ursid milks. Three artificial milk formulae used to feed giant panda cubs were also analysed, and were found to differ markedly in component content from natural panda milk. These findings have implications for the dependence of the ontogeny of all species of bears, and potentially other members of the Carnivora and beyond, on the complexity and sequential changes in maternal provision of micrometabolites in the immediate period after birth.

  11. Changes in the Milk Metabolome of the Giant Panda (Ailuropoda melanoleuca) with Time after Birth – Three Phases in Early Lactation and Progressive Individual Differences

    Science.gov (United States)

    Zhang, Tong; Zhang, Rong; Zhang, Liang; Zhang, Zhihe; Hou, Rong; Wang, Hairui; Loeffler, I. Kati; Watson, David G.; Kennedy, Malcolm W.

    2015-01-01

    Ursids (bears) in general, and giant pandas in particular, are highly altricial at birth. The components of bear milks and their changes with time may be uniquely adapted to nourish relatively immature neonates, protect them from pathogens, and support the maturation of neonatal digestive physiology. Serial milk samples collected from three giant pandas in early lactation were subjected to untargeted metabolite profiling and multivariate analysis. Changes in milk metabolites with time after birth were analysed by Principal Component Analysis, Hierarchical Cluster Analysis and further supported by Orthogonal Partial Least Square-Discriminant Analysis, revealing three phases of milk maturation: days 1–6 (Phase 1), days 7–20 (Phase 2), and beyond day 20 (Phase 3). While the compositions of Phase 1 milks were essentially indistinguishable among individuals, divergences emerged during the second week of lactation. OPLS regression analysis positioned against the growth rate of one cub tentatively inferred a correlation with changes in the abundance of a trisaccharide, isoglobotriose, previously observed to be a major oligosaccharide in ursid milks. Three artificial milk formulae used to feed giant panda cubs were also analysed, and were found to differ markedly in component content from natural panda milk. These findings have implications for the dependence of the ontogeny of all species of bears, and potentially other members of the Carnivora and beyond, on the complexity and sequential changes in maternal provision of micrometabolites in the immediate period after birth. PMID:26630345

  12. Changes in the Milk Metabolome of the Giant Panda (Ailuropoda melanoleuca with Time after Birth--Three Phases in Early Lactation and Progressive Individual Differences.

    Directory of Open Access Journals (Sweden)

    Tong Zhang

    Full Text Available Ursids (bears in general, and giant pandas in particular, are highly altricial at birth. The components of bear milks and their changes with time may be uniquely adapted to nourish relatively immature neonates, protect them from pathogens, and support the maturation of neonatal digestive physiology. Serial milk samples collected from three giant pandas in early lactation were subjected to untargeted metabolite profiling and multivariate analysis. Changes in milk metabolites with time after birth were analysed by Principal Component Analysis, Hierarchical Cluster Analysis and further supported by Orthogonal Partial Least Square-Discriminant Analysis, revealing three phases of milk maturation: days 1-6 (Phase 1, days 7-20 (Phase 2, and beyond day 20 (Phase 3. While the compositions of Phase 1 milks were essentially indistinguishable among individuals, divergences emerged during the second week of lactation. OPLS regression analysis positioned against the growth rate of one cub tentatively inferred a correlation with changes in the abundance of a trisaccharide, isoglobotriose, previously observed to be a major oligosaccharide in ursid milks. Three artificial milk formulae used to feed giant panda cubs were also analysed, and were found to differ markedly in component content from natural panda milk. These findings have implications for the dependence of the ontogeny of all species of bears, and potentially other members of the Carnivora and beyond, on the complexity and sequential changes in maternal provision of micrometabolites in the immediate period after birth.

  13. Information needs about palliative care and euthanasia: A survey of patients in different phases of their cancer trajectory.

    Science.gov (United States)

    Beernaert, Kim; Haverbeke, Chloë; Van Belle, Simon; Deliens, Luc; Cohen, Joachim

    2018-01-01

    We assessed information provision and information needs about illness course, treatments, palliative care and euthanasia in cancer patients. Cancer patients consulting a university hospital (N=620) filled out a questionnaire. Their cancer related data were collected through the treating oncologist. This study is performed in Belgium, where "palliative care for all" is a patient's right embedded in the law and euthanasia is possible under certain conditions. Around 80% received information about their illness course and treatments. Ten percent received information about palliative care and euthanasia. Most information about palliative care and euthanasia was given when the patient had a life expectancy of less than six months. However, a quarter of those in earlier phases in their illness trajectory, particularly those who experienced high pain, fatigue or nausea requested more information on these topics. Many patients want more information about palliative care and euthanasia than what is currently provided, also those in an earlier than terminal phase of their disease. Healthcare professionals should be more responsive, already from diagnosis, to the information needs about palliative care and possible end-of-life decisions. This should be patient-tailored, as some patients want more and some patients want less information. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Joint test rig for testing and calibrating of different methods of two-phase mass flow measurement

    International Nuclear Information System (INIS)

    Reimann, J.; Demski, A.; Hahn, H.; Harten, U.; John, H.; Megerle, A.; Mueller, S.; Pawlak, L.; Wanner, E.

    1977-01-01

    The steam-water loop was completed by building in two throttling valves upstream of the mixing chamber. By producing steam by throttling the total mass flow may be increased up to 35% compared to the former method of operating the loop. Furthermore, throttling stabilizes the single phase mass flow measurement. The data aquisition system and computation of the reference values has been finished. The computer program contains the equations of state of steam/water and the calibration curves for all signal transducers. The 5 beam γ-densitometer has been finished mechanically and supplied with the electronics. First calibration tests are fully satisfactory. The instrumentation of the air-water loop completed. At low quality the mass fluxes are increased by a factor of 5 compared with the steam-water-loop. The regime of dispersed bubble flow is fully reached in the test section. To detect flow regimes air-water as well as in steam-water flow, a local impedance probe was used. In addition, the phase distribution across the channel could be detected by traversing the probe. The boundaries of the air-water flow regimes detected by the probe are in good correspondance with other investigations. For the first time, such experiments have been carried out in horizontal steam-water flow. The results indicate that the region of slug flow becomes smaller with increasing pressure. (orig./RW) [de

  15. Probing the hadronic phase with resonances of different lifetimes in Pb-Pb collisions with ALICE arXiv

    CERN Document Server

    Agrawal, Neelima

    The ALICE experiment has measured the production of a rich set of hadronic resonances, such as $\\rho(770)^{0}$, ${\\rm K}^{\\ast}(892)^{0}$, $\\phi$(1020), $\\Sigma^{\\pm}$(1385), $\\Lambda(1520)$ and $\\Xi^{\\ast 0}$ in pp, p-Pb and Pb-Pb collisions at various energies at the LHC. A comprehensive overview and the latest results are presented in this paper. Special focus is given to the role of hadronic resonances for the study of final-state effects in high-energy collisions. In particular, the measurement of resonance production in heavy-ion collisions has the capability to provide insight into the existence of a prolonged hadronic phase after hadronisation. The observation of the suppression of the production of $\\Lambda(1520)$ resonance in central Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV adds further support to the existence of such a dense hadronic phase, as already evidenced by the ratios ${\\rm K}^{\\ast}(892)^{0}$/${\\rm K}$ and $\\rho(770)^{0}$/$\\pi$.

  16. Linear and mass attenuation coefficient for CdTe compound of X-rays from 10 to 100 keV energy range in different phases

    Energy Technology Data Exchange (ETDEWEB)

    Saim, A., E-mail: saim1989asma@gmail.com; Tebboune, A.; Berkok, H.; Belameiri, N.; Belbachir, A.H.

    2014-07-25

    The Full Potential Linear Muffin Tin Orbitals method within the density functional theory has been utilized to calculate structural and electronic properties of the CdTe compound. We have checked that the CdTe has two phase-transitions from zinc-blend to cinnabar and from cinnabar to rocksalt. We have found that the rigidity, the energy and the nature of the gap change according to the phase change, so we can predict that a CdTe detector may have different behaviors in different phase conditions. In order to investigate this behavior change, the linear and the mass attenuation coefficients of X-ray in rocksalt, zinc-blend and cinnabar structures are calculated from 10 keV to100 keV, using the XCOM data. We have found that when CdTe undergoes a phase transition from zinc-blend to cinnabar, its linear attenuation coefficient decreases down to a value of about 100 times smaller than its initial one, and when it undergoes a transition from cinnabar to rocksalt it increases up to a value about 90 times larger than its initial one.

  17. Gender differences in quality of life and functional disability for depression outpatients with or without residual symptoms after acute phase treatment in China.

    Science.gov (United States)

    Zhao, Na; Wang, Xiaohong; Wu, Wenyuan; Hu, Yongdong; Niu, Yajuan; Wang, Xueyi; Gao, Chengge; Zhang, Ning; Fang, Yiru; Huang, Jizhong; Liu, Tiebang; Jia, Fujun; Zhu, Xuequan; Hu, Jian; Wang, Gang

    2017-09-01

    Depression is associated with substantial personal suffering and reduced quality of life and functioning. The aim of this study was to investigate gender differences on quality of life and functional impairment of outpatients with depression after acute phase treatment. 1503 depression outpatients were recruited from eleven hospitals in China. Subjects were evaluated with sociodemographic characteristics, history and self-report instruments, related to severity of symptoms, function and quality of life. All data were analyzed to determine the gender differences. Men had a younger age at onset and the first onset age, higher education compared to women in total patients and with or without residual symptoms group. Using regression analysis, it was found that gender was significantly statistically related to severity scores of SDS and had no correlation with Q-LES-Q-SF total scores. In the residual symptoms group, greater functional impairment was noted by men in the area of work and social life. Significant gender differences of mood, work and sexual life in quality of life were observed. This is a cross-sectional study of depressed outpatients and duration of acute phase treatment may not an adequate time to measure changes. Depression appears to affect men more seriously than women after acute phase treatment. Men had a younger age at onset and the first onset age, higher education, more functional impairment and lower satisfaction of quality of life in mood, work and sexual life. Gender differences affect acute treatment, remission and recovery. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Nanoscale nuclei in phase change materials: Origin of different crystallization mechanisms of Ge2Sb2Te5 and AgInSbTe

    International Nuclear Information System (INIS)

    Lee, Bong-Sub; Bogle, Stephanie N.; Darmawikarta, Kristof; Abelson, John R.; Shelby, Robert M.; Retter, Charles T.; Burr, Geoffrey W.; Raoux, Simone; Bishop, Stephen G.

    2014-01-01

    Phase change memory devices are based on the rapid and reversible amorphous-to-crystalline transformations of phase change materials, such as Ge 2 Sb 2 Te 5 and AgInSbTe. Since the maximum switching speed of these devices is typically limited by crystallization speed, understanding the crystallization process is of crucial importance. While Ge 2 Sb 2 Te 5 and AgInSbTe show very different crystallization mechanisms from their melt-quenched states, the nanostructural origin of this difference has not been clearly demonstrated. Here, we show that an amorphous state includes different sizes and number of nanoscale nuclei, after thermal treatment such as melt-quenching or furnace annealing is performed. We employ fluctuation transmission electron microscopy to detect nanoscale nuclei embedded in amorphous materials, and use a pump-probe laser technique and atomic force microscopy to study the kinetics of nucleation and growth. We confirm that melt-quenched amorphous Ge 2 Sb 2 Te 5 includes considerably larger and more quenched-in nuclei than its as-deposited state, while melt-quenched AgInSbTe does not, and explain this contrast by the different ratio between quenching time and nucleation time in these materials. In addition to providing insights to the crystallization process in these technologically important devices, this study presents experimental illustrations of temperature-dependence of nucleation rate and growth speed, which was predicted by theory of phase transformation but rarely demonstrated

  19. Can harmonized regulation overcome intra-European differences? Insights from a European Phase III stem cell trial.

    Science.gov (United States)

    Hauskeller, Christine

    2017-09-01

    Harmonized regulation of research with human stem cells in Europe has shaped innovation in regenerative medicine. Findings from a Phase III academic clinical trial of an autologous cell procedure illustrate the obstacles that a multinational trial faces. A typology of the obstacles encountered, may help other teams embarking upon trials. The findings throw light on the situation of clinician-scientists in clinical innovation, as the expertise to run scientific trials is very complex. The innovation route of clinical translation takes insufficient account of the interdependencies between multiple social and cultural factors from outside the laboratory and the clinic. For ethical reasons, however, academic and business routes to stem cell treatments ought to be enabled by the regulators. Suggestions arise, how academics can prepare for trials, that academic research needs better institutional support and that new models of medical innovation may need to be developed for regenerative medicine.

  20. [Profile of sulphated glycosaminoglycans content in the murine uterus during the different phases of the estrous cycle].

    Science.gov (United States)

    Gomes, Regina Célia Teixeira; Simões, Ricardo Santos; Soares, José Maria; Nader, Helena Bonciani; Simões, Manuel de Jesus; Baracat, Edmund C

    2007-01-01

    Identification and quantitation of sulphated glycosaminoglycans (GAGs) in the uterus of female mice during the estrous cycle. Four groups (n = 10 each) of virgin, 100-day old female mice were assembled according to the estrous cycle phase: proestrus, estrus, metaestrus and diestrus. Samples of the median portion of uterine horns were processed for light microscopy examination (H/E and Alcian blue + PAS). The GAGs were extracted and characterized by agarose gel electrophoresis. Data were analyzed by the unpaired Student's t-test. At light microscopy GAGs appear in all layers of the uterus, especially in the endometrium, between collagen fibers, in the basal membrane and around fibroblasts. Biochemical analyses disclosed presence of dermatan sulphate (DS), chondroitin sulphate (CS and heparan sulphate (HS) during all estral cycle phases. There was no clear electrophoretic separation between DS and CS, thus these two GAGs were considered together (DS+CS) (proestrus = 0.854 +/- 0.192; estrus = 1.073 +/- 0.254; metaestrus = 1.003 +/- 0.255; diestrus = 0.632 +/- 0.443 microg/mg). HS was as follows: proestrus = 0.092 +/- 0.097; estrus = 0.180 +/- 0.141; metaestrus = 0.091 +/- 0.046; diestrus = 0.233 +/- 0.147 microg/mg. The uterine content of DS+CS peaked at estrus (estrogenic action) and that of HS at diestrus (progestagen action). Due to a constant turnover process, there are definite alterations in the uterine profile of GAGs content during the estrous cycle in mice, which may be modulated by female sex hormones.