WorldWideScience

Sample records for relevant frequency range

  1. The frequency range of TMJ sounds.

    Science.gov (United States)

    Widmalm, S E; Williams, W J; Djurdjanovic, D; McKay, D C

    2003-04-01

    There are conflicting opinions about the frequency range of temporomandibular joint (TMJ) sounds. Some authors claim that the upper limit is about 650 Hz. The aim was to test the hypothesis that TMJ sounds may contain frequencies well above 650 Hz but that significant amounts of their energy are lost if the vibrations are recorded using contact sensors and/or travel far through the head tissues. Time-frequency distributions of 172 TMJ clickings (three subjects) were compared between recordings with one microphone in the ear canal and a skin contact transducer above the clicking joint and between recordings from two microphones, one in each ear canal. The energy peaks of the clickings recorded with a microphone in the ear canal on the clicking side were often well above 650 Hz and always in a significantly higher area (range 117-1922 Hz, P 375 Hz) or in microphone recordings from the opposite ear canal (range 141-703 Hz). Future studies are required to establish normative frequency range values of TMJ sounds but need methods also capable of recording the high frequency vibrations.

  2. T-ray relevant frequencies for osteosarcoma classification

    Science.gov (United States)

    Withayachumnankul, W.; Ferguson, B.; Rainsford, T.; Findlay, D.; Mickan, S. P.; Abbott, D.

    2006-01-01

    We investigate the classification of the T-ray response of normal human bone cells and human osteosarcoma cells, grown in culture. Given the magnitude and phase responses within a reliable spectral range as features for input vectors, a trained support vector machine can correctly classify the two cell types to some extent. Performance of the support vector machine is deteriorated by the curse of dimensionality, resulting from the comparatively large number of features in the input vectors. Feature subset selection methods are used to select only an optimal number of relevant features for inputs. As a result, an improvement in generalization performance is attainable, and the selected frequencies can be used for further describing different mechanisms of the cells, responding to T-rays. We demonstrate a consistent classification accuracy of 89.6%, while the only one fifth of the original features are retained in the data set.

  3. PERMITTIVITY RESEARCH OF BIOLOGICAL SOLUTIONS IN GIGAHERTZ FREQUENCY RANGE

    Directory of Open Access Journals (Sweden)

    Anton S. Demin

    2017-07-01

    Full Text Available Subject of Research. We present results of permittivity research in gigahertz frequency range for saline and glucose solutions used in medical practice. Experiment results are substantiated theoretically on the basis of Debye-Cole model. Method. Researches have been carried out on blood plasma of healthy donor, water, normal saline and glucose solutions with different concentration from 3 to 12 mmol/l. Experiments have been performed by an active nearfield method based on measuring the impedance of a plane air-liquid boundary with open end of coaxial waveguide in the frequency range from 1 to 12 GHz. Measurement results have been processed with the use of vector analyzer computer system from Rohde & Schwarz. Transmittance spectra have been determined by means of IR-spectrometer from TENZOR-Bruker. Main Results. Simulation results have shown good agreement between the experimental results and the model, as well as the choice of the main parameters of the Debye-Cole model in the studied frequency range for all media. It has been shown that the range of 3-6 GHz can be considered as the main one in the development of diagnostic sensors for the non-invasive analysis of the glucose concentration in the human blood. Practical Relevance. Electrodynamic models of test fluid replacing human blood give the possibility to simulate the sensor basic characteristics for qualitative and quantitative estimation of glucose concentration in human blood and can be used to create an experimental sample of a non- invasive glucometer.

  4. Characteristics of different frequency ranges in scanning electron microscope images

    International Nuclear Information System (INIS)

    Sim, K. S.; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S.

    2015-01-01

    We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement

  5. Characteristics of different frequency ranges in scanning electron microscope images

    Energy Technology Data Exchange (ETDEWEB)

    Sim, K. S., E-mail: kssim@mmu.edu.my; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S. [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia)

    2015-07-22

    We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement.

  6. Cultural relevance of a fruit and vegetable food frequency questionnaire.

    Science.gov (United States)

    Paisley, Judy; Greenberg, Marlene; Haines, Jess

    2005-01-01

    Canada's multicultural population poses challenges for culturally competent nutrition research and practice. In this qualitative study, the cultural relevance of a widely used semi-quantitative fruit and vegetable food frequency questionnaire (FFQ) was examined among convenience samples of adults from Toronto's Cantonese-, Mandarin-, Portuguese-, and Vietnamese-speaking communities. Eighty-nine participants were recruited through community-based organizations, programs, and advertisements to participate in semi-structured interviews moderated in their native language. Data from the interviews were translated into English and transcribed for analysis using the constant comparative approach. Four main themes emerged from the analysis: the cultural relevance of the foods listed on the FFQ, words with multiple meanings, the need for culturally appropriate portion-size prompts, and the telephone survey as a Western concept. This research highlights the importance of investing resources to develop culturally relevant dietary assessment tools that ensure dietary assessment accuracy and, more important, reduce ethnocentric biases in food and nutrition research and practice. The transferability of findings must be established through further research.

  7. Predicting Achievable Fundamental Frequency Ranges in Vocalization Across Species.

    Directory of Open Access Journals (Sweden)

    Ingo Titze

    2016-06-01

    Full Text Available Vocal folds are used as sound sources in various species, but it is unknown how vocal fold morphologies are optimized for different acoustic objectives. Here we identify two main variables affecting range of vocal fold vibration frequency, namely vocal fold elongation and tissue fiber stress. A simple vibrating string model is used to predict fundamental frequency ranges across species of different vocal fold sizes. While average fundamental frequency is predominantly determined by vocal fold length (larynx size, range of fundamental frequency is facilitated by (1 laryngeal muscles that control elongation and by (2 nonlinearity in tissue fiber tension. One adaptation that would increase fundamental frequency range is greater freedom in joint rotation or gliding of two cartilages (thyroid and cricoid, so that vocal fold length change is maximized. Alternatively, tissue layers can develop to bear a disproportionate fiber tension (i.e., a ligament with high density collagen fibers, increasing the fundamental frequency range and thereby vocal versatility. The range of fundamental frequency across species is thus not simply one-dimensional, but can be conceptualized as the dependent variable in a multi-dimensional morphospace. In humans, this could allow for variations that could be clinically important for voice therapy and vocal fold repair. Alternative solutions could also have importance in vocal training for singing and other highly-skilled vocalizations.

  8. Extension of White's layered model to the full frequency range

    NARCIS (Netherlands)

    Vogelaar, Bouko; Smeulders, D.M.J.

    2007-01-01

    The low-frequency theory of the White model to predict the dispersion and intrinsic attenuation in a single porous skeleton saturated with periodic layers of two immiscible fluids is extended to the full frequency range using the Biot theory. The extension is similar to the Dutta–Odé model for

  9. Absorption properties of water-in-oil emulsions in the low THz frequency range

    DEFF Research Database (Denmark)

    Møller, Uffe; Folkenberg, Jacob Riis; Jepsen, Peter Uhd

    We use transmission THz spectroscopy to investigate the absorption properties of water-in-oil emulsions with water content varying in the 0-20% range, relevant for a range of food products. We find that at low frequencies the effective absorption coefficient of the emulsion is suppressed compared...... to bulk water....

  10. Ultrafast optical ranging using microresonator soliton frequency combs

    Science.gov (United States)

    Trocha, P.; Karpov, M.; Ganin, D.; Pfeiffer, M. H. P.; Kordts, A.; Wolf, S.; Krockenberger, J.; Marin-Palomo, P.; Weimann, C.; Randel, S.; Freude, W.; Kippenberg, T. J.; Koos, C.

    2018-02-01

    Light detection and ranging is widely used in science and industry. Over the past decade, optical frequency combs were shown to offer advantages in optical ranging, enabling fast distance acquisition with high accuracy. Driven by emerging high-volume applications such as industrial sensing, drone navigation, or autonomous driving, there is now a growing demand for compact ranging systems. Here, we show that soliton Kerr comb generation in integrated silicon nitride microresonators provides a route to high-performance chip-scale ranging systems. We demonstrate dual-comb distance measurements with Allan deviations down to 12 nanometers at averaging times of 13 microseconds along with ultrafast ranging at acquisition rates of 100 megahertz, allowing for in-flight sampling of gun projectiles moving at 150 meters per second. Combining integrated soliton-comb ranging systems with chip-scale nanophotonic phased arrays could enable compact ultrafast ranging systems for emerging mass applications.

  11. Investigation of a slot nanoantenna in optical frequency range

    Science.gov (United States)

    Dinesh kumar, V.; Asakawa, Kiyoshi

    2009-11-01

    Following the analogy of radio frequency slot antenna and its complementary dipole, we propose the implementation of a slot nanoantenna (SNA) in the optical frequency range. Using finite-difference time-domain (FDTD) method, we investigate the electromagnetic (EM) properties of a SNA formed in a thin gold film and compare the results with the properties of a gold dipole nanoantenna (DNA) of the same dimension as the slot. It is found that the response of the SNA is very similar to the DNA, like their counterparts in the radio frequency (RF) range. The SNA can enhance the near field intensity of incident field which strongly depends on its feedgap dimension. The resonance of the SNA is influenced by its slot length; for the increasing slot length, resonant frequency decreases whereas the sharpness of resonance increases. Besides, the resonance of the SNA is found sensitive to the thickness of metal film, when the latter is smaller than the skin depth. The effect of polarization of incident field on the EM response of the SNA was examined; the field enhancement is optimum when polarization is parallel to the feedgap. Finally, we calculate the radiation patterns of the DNA and SNA and compare them with those of the RF dipole antenna. The radiation pattern of the SNA is found to be independent of its slot length when excited at resonant frequency. To the best of our knowledge, this is the first study on a slot antenna in the optical frequency.

  12. Experimental Limits on Gravitational Waves in the MHz frequency Range

    Energy Technology Data Exchange (ETDEWEB)

    Lanza, Robert Jr. [Univ. of Chicago, IL (United States)

    2015-03-01

    This thesis presents the results of a search for gravitational waves in the 1-11MHz frequency range using dual power-recycled Michelson laser interferometers at Fermi National Accelerator Laboratory. An unprecedented level of sensitivity to gravitational waves in this frequency range has been achieved by cross-correlating the output fluctuations of two identical and colocated 40m long interferometers. This technique produces sensitivities better than two orders of magnitude below the quantum shot-noise limit, within integration times of less than 1 hour. 95% confidence level upper limits are placed on the strain amplitude of MHz frequency gravitational waves at the 10-21 Hz-1/2 level, constituting the best direct limits to date at these frequencies. For gravitational wave power distributed over this frequency range, a broadband upper limit of 2.4 x 10-21Hz-1/2 at 95% confidence level is also obtained. This thesis covers the detector technology, the commissioning and calibration of the instrument, the statistical data analysis, and the gravitational wave limit results. Particular attention is paid to the end-to-end calibration of the instrument’s sensitivity to differential arm length motion, and so to gravitational wave strain. A detailed statistical analysis of the data is presented as well.

  13. Dielectric characterization of materials at microwave frequency range

    Directory of Open Access Journals (Sweden)

    J. de los Santos

    2003-01-01

    Full Text Available In this study a coaxial line was used to connect a microwave-frequency Network Analyzer and a base moving sample holder for dielectric characterization of ferroelectric materials in the microwave range. The main innovation of the technique is the introduction of a special sample holder that eliminates the air gap effect by pressing sample using a fine pressure system control. The device was preliminary tested with alumina (Al2O3 ceramics and validated up to 2 GHz. Dielectric measurements of lanthanum and manganese modified lead titanate (PLTM ceramics were carried out in order to evaluate the technique for a high permittivity material in the microwave range. Results showed that such method is very useful for materials with high dielectric permittivities, which is generally a limiting factor of other techniques in the frequency range from 50 MHz to 2 GHz.

  14. LTP in Hippocampal Area CA1 Is Induced by Burst Stimulation over a Broad Frequency Range Centered around Delta

    Science.gov (United States)

    Grover, Lawrence M.; Kim, Eunyoung; Cooke, Jennifer D.; Holmes, William R.

    2009-01-01

    Long-term potentiation (LTP) is typically studied using either continuous high-frequency stimulation or theta burst stimulation. Previous studies emphasized the physiological relevance of theta frequency; however, synchronized hippocampal activity occurs over a broader frequency range. We therefore tested burst stimulation at intervals from 100…

  15. Optimal Frequency Ranges for Sub-Microsecond Precision Pulsar Timing

    Science.gov (United States)

    Lam, Michael Timothy; McLaughlin, Maura; Cordes, James; Chatterjee, Shami; Lazio, Joseph

    2018-01-01

    Precision pulsar timing requires optimization against measurement errors and astrophysical variance from the neutron stars themselves and the interstellar medium. We investigate optimization of arrival time precision as a function of radio frequency and bandwidth. We find that increases in bandwidth that reduce the contribution from receiver noise are countered by the strong chromatic dependence of interstellar effects and intrinsic pulse-profile evolution. The resulting optimal frequency range is therefore telescope and pulsar dependent. We demonstrate the results for five pulsars included in current pulsar timing arrays and determine that they are not optimally observed at current center frequencies. We also find that arrival-time precision can be improved by increases in total bandwidth. Wideband receivers centered at high frequencies can reduce required overall integration times and provide significant improvements in arrival time uncertainty by a factor of $\\sim$$\\sqrt{2}$ in most cases, assuming a fixed integration time. We also discuss how timing programs can be extended to pulsars with larger dispersion measures through the use of higher-frequency observations.

  16. Ionospheric Coherence Bandwidth Measurements in the Lower VHF Frequency Range

    Science.gov (United States)

    Suszcynsky, D. M.; Light, M. E.; Pigue, M. J.

    2015-12-01

    The United States Department of Energy's Radio Frequency Propagation (RFProp) experiment consists of a satellite-based radio receiver suite to study various aspects of trans-ionospheric signal propagation and detection in four frequency bands, 2 - 55 MHz, 125 - 175 MHz, 365 - 415 MHz and 820 - 1100 MHz. In this paper, we present simultaneous ionospheric coherence bandwidth and S4 scintillation index measurements in the 32 - 44 MHz frequency range collected during the ESCINT equatorial scintillation experiment. 40-MHz continuous wave (CW) and 32 - 44 MHz swept frequency signals were transmitted simultaneously to the RFProp receiver suite from the Reagan Test Site at Kwajalein Atoll in the Marshall Islands (8.7° N, 167.7° E) in three separate campaigns during the 2014 and 2015 equinoxes. Results show coherence bandwidths as small as ~ 1 kHz for strong scintillation (S4 > 0.7) and indicate a high degree of ionospheric variability and irregularity on 10-m spatial scales. Spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities are also observed and are dominant at low elevation angles. The results are compared to previous measurements and available scaling laws.

  17. Modal density of rectangular structures in a wide frequency range

    Science.gov (United States)

    Parrinello, A.; Ghiringhelli, G. L.

    2018-04-01

    A novel approach to investigate the modal density of a rectangular structure in a wide frequency range is presented. First, the modal density is derived, in the whole frequency range of interest, on the basis of sound transmission through the infinite counterpart of the structure; then, it is corrected by means of the low-frequency modal behavior of the structure, taking into account actual size and boundary conditions. A statistical analysis reveals the connection between the modal density of the structure and the transmission of sound through its thickness. A transfer matrix approach is used to compute the required acoustic parameters, making it possible to deal with structures having arbitrary stratifications of different layers. A finite element method is applied on coarse grids to derive the first few eigenfrequencies required to correct the modal density. Both the transfer matrix approach and the coarse grids involved in the finite element analysis grant high efficiency. Comparison with alternative formulations demonstrates the effectiveness of the proposed methodology.

  18. The technology of the ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Hoffman, D.J.; Barber, G.C.

    1988-01-01

    Plasma heating in the ion cyclotron range of frequencies (ICRF) is the least expensive means of accomplishing auxiliary heating in fusion experiments. RF systems comprise two major elements: the transmitter and the antenna. The state of the art for the transmitter is already at the megawatt level. The technology of the antenna is strongly coupled to the plasma character. Typically, these antennas are designed to operate at a high power density (1.2 kW/cm 2 ) with an efficiency of 96%. ICRF technology and options have improved over the past few years, owing to development and experiments; however, the optimal combination of options can be defined only when results from confinement experiments and test facilities are in hand. 19 refs., 5 figs., 1 tab

  19. Manufacturing technologies for ultrasonic transducers in a broad frequency range

    OpenAIRE

    Gebhardt, Sylvia; Hohlfeld, Kai; Günther, Paul; Neubert, Holger

    2018-01-01

    According to the application field, working frequency of ultrasonic transducers needs to be tailored to a certain value. Low frequency ultrasonic transducers with working frequencies of 1 kHz to 1 MHz are especially interesting for sonar applications, whereas high frequency ultrasonic transducers with working frequencies higher than 15 MHz are favorable for high-resolution imaging in biomedical and non-destructive evaluation. Conventional non-destructive testing devices and clinical ultrasoun...

  20. Range and Frequency of Africanized Honey Bees in California (USA)

    Science.gov (United States)

    Kono, Yoshiaki; Kohn, Joshua R.

    2015-01-01

    Africanized honey bees entered California in 1994 but few accounts of their northward expansion or their frequency relative to European honey bees have been published. We used mitochondrial markers and morphometric analyses to determine the prevalence of Africanized honeybees in San Diego County and their current northward progress in California west of the Sierra Nevada crest. The northernmost African mitotypes detected were approximately 40 km south of Sacramento in California’s central valley. In San Diego County, 65% of foraging honey bee workers carry African mitochondria and the estimated percentage of Africanized workers using morphological measurements is similar (61%). There was no correlation between mitotype and morphology in San Diego County suggesting Africanized bees result from bidirectional hybridization. Seventy percent of feral hives, but only 13% of managed hives, sampled in San Diego County carried the African mitotype indicating that a large fraction of foraging workers in both urban and rural San Diego County are feral. We also found a single nucleotide polymorphism at the DNA barcode locus COI that distinguishes European and African mitotypes. The utility of this marker was confirmed using 401 georeferenced honey bee sequences from the worldwide Barcode of Life Database. Future censuses can determine whether the current range of the Africanized form is stable, patterns of introgression at nuclear loci, and the environmental factors that may limit the northern range of the Africanized honey bee. PMID:26361047

  1. Long range ultra-high frequency (UHF) radio frequency identification (RFID) antenna design

    Science.gov (United States)

    Reynolds, Nathan D.

    There is an ever-increasing demand for radio frequency identification (RFID) tags that are passive, long range, and mountable on multiple surfaces. Currently, RFID technology is utilized in numerous applications such as supply chain management, access control, and public transportation. With the combination of sensory systems in recent years, the applications of RFID technology have been extended beyond tracking and identifying. This extension includes applications such as environmental monitoring and healthcare applications. The available sensory systems usually operate in the medium or high frequency bands and have a low read range. However, the range limitations of these systems are being overcome by the development of RFID sensors focused on utilizing tags in the ultra-high frequency (UHF) band. Generally, RFID tags have to be mounted to the object that is being identified. Often the objects requiring identification are metallic. The inherent properties of metallic objects have substantial effects on nearby electromagnetic radiation; therefore, the operation of the tag antenna is affected when mounted on a metallic surface. This outlines one of the most challenging problems for RFID systems today: the optimization of tag antenna performance in a complex environment. In this research, a novel UHF RFID tag antenna, which has a low profile, long range, and is mountable on metallic surfaces, is designed analytically and simulated using a 3-D electromagnetic simulator, ANSYS HFSS. A microstrip patch antenna is selected as the antenna structure, as patch antennas are low profile and suitable for mounting on metallic surfaces. Matching and theoretical models of the microstrip patch antenna are investigated. Once matching and theory of a microstrip patch antenna is thoroughly understood, a unique design technique using electromagnetic band gap (EBG) structures is explored. This research shows that the utilization of an EBG structure in the patch antenna design yields

  2. Radio frequency heating in the ion-cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Swanson, D.G.

    1985-01-01

    Both the theory of the absorption process in the ion-cyclotron range of frequencies and some of the experiments which slow the promise and problems with radio frequency plasma heating in this range are discussed. It is shown that mode conversion is invariably involved in the process and so an extensive review of mode conversion theory, expecially as it applies to problems with back-to-back cutoff-resonance pairs, is included. This includes a discussion of the tunneling equation with and without absorption effects and with and without energy conservation. The general theory is applied to various ion-cyclotron harmonics, the two-ion hybrid resonance, and to a case where a wave converts to a Bernstein mode at the plasma edge. The results are given analytically for a variety of cases without absorption, and empirical formulas are given for the second and third harmonics of the ion-cyclotron frequency, which include effects of absorption. Various problem areas in the theory are also discussed with some of the limitations caused by the approximations involved. A number of experiments are also discussed which show effective heating, and some show the features of the mode conversion process, indicating that the general processes of absorption are reasonably well understood. Areas where further work is necessary, both in fundamental theory and in comparing theory with experiment, are also discussed

  3. New fractal structures for frequencies close to the visible range

    DEFF Research Database (Denmark)

    Malureanu, Radu; Sandru, A.; Andryieuski, Andrei

    2011-01-01

    In this paper we present a new type of fractal resonator to be used in the red/NIR region of the spectra. The structure presents high-transmission band in 795-825nm range. The stop band is in the 683-731 nm range. Due to the huge difference in the spectra within such a short range, the structure...

  4. Intensity autocorrelation measurements of frequency combs in the terahertz range

    Science.gov (United States)

    Benea-Chelmus, Ileana-Cristina; Rösch, Markus; Scalari, Giacomo; Beck, Mattias; Faist, Jérôme

    2017-09-01

    We report on direct measurements of the emission character of quantum cascade laser based frequency combs, using intensity autocorrelation. Our implementation is based on fast electro-optic sampling, with a detection spectral bandwidth matching the emission bandwidth of the comb laser, around 2.5 THz. We find the output of these frequency combs to be continuous even in the locked regime, but accompanied by a strong intensity modulation. Moreover, with our record temporal resolution of only few hundreds of femtoseconds, we can resolve correlated intensity modulation occurring on time scales as short as the gain recovery time, about 4 ps. By direct comparison with pulsed terahertz light originating from a photoconductive emitter, we demonstrate the peculiar emission pattern of these lasers. The measurement technique is self-referenced and ultrafast, and requires no reconstruction. It will be of significant importance in future measurements of ultrashort pulses from quantum cascade lasers.

  5. Intrinsic vs. spurious long-range memory in high-frequency records of environmental radioactivity

    International Nuclear Information System (INIS)

    Donner, R.V.; Potirakis, S.M.; Barbosa, S.M.; Matos, J.A.O.; Pereira, A.J.S.C.; Neves, L.J.M.F.

    2015-01-01

    The presence or absence of long-range correlations in the environmental radioactivity fluctuations has recently attracted considerable interest. Among a multiplicity of practically relevant applications, identifying and disentangling the environmental factors controlling the variable concentrations of the radioactive noble gas radon is important for estimating its effect on human health and the efficiency of possible measures for reducing the corresponding exposition. In this work, we present a critical re-assessment of a multiplicity of complementary methods that have been previously applied for evaluating the presence of long-range correlations and fractal scaling in environmental radon variations with a particular focus on the specific properties of the underlying time series. As an illustrative case study, we subsequently re-analyze two high-frequency records of indoor radon concentrations from Coimbra, Portugal, each of which spans several weeks of continuous measurements at a high temporal resolution of five minutes. Our results reveal that at the study site, radon concentrations exhibit complex multi-scale dynamics with qualitatively different properties at different time-scales: (i) essentially white noise in the high-frequency part (up to time-scales of about one hour), (ii) spurious indications of a non-stationary, apparently long-range correlated process (at time scales between some hours and one day) arising from marked periodic components, and (iii) low-frequency variability indicating a true long-range dependent process. In the presence of such multi-scale variability, common estimators of long-range memory in time series are prone to fail if applied to the raw data without previous separation of time-scales with qualitatively different dynamics. (authors)

  6. INVESTIGATION OF THE FREQUENCY-TEMPERATURE RELATIONSHIP OF THE DIELECTRIC PERMITTIVITY OF THE PZT PIEZOCERAMICS IN THE LOW FREQUENCY RANGE

    Directory of Open Access Journals (Sweden)

    A. I. ZOLOTAREVSKIY

    2018-05-01

    Full Text Available Purpose. To investigate the frequency-temperature relationship of the dielectric permittivity of PZT piezoceramics in the low frequency range. Methodology. To obtain the frequency-temperature relationship of the dielectric permittivity of the PZT piezoceramics, a technique was used to determine the capacitance of the capacitor, between which plates the sample was placed. The value of the dielectric permittivity of the sample was calculated from the capacitor capacitance obtained. Findings. The frequency-temperature relationship of the dielectric permittivity of the PZT piezoceramics in the low frequency range has been obtained by the authors. The dielectric permittivity is not practically related to the frequency of the alternating voltage at a low temperature, with increasing in temperature its value increases and frequency relationship is observed. The temperature relationship of the dielectric permittivity of the PZT piezoceramics is satisfactorily described by the exponential functional dependence in the low-temperature range. The activation energy of the PZT piezoceramics polarization is determined from the graph of the dependence of the logarithm of the dielectric permittivity upon the inverse temperature. Different values of the activation energy for the two temperature regions prove on the existence of different mechanisms of the PZT piezoceramics polarization in the temperature range being investigated. Originality. The authors investigated the frequency-temperature relationship of the dielectric permittivity of the PZT piezoceramics in the low-frequency range. It is established that the temperature relationship of the dielectric permittivity of the PZT piezoceramics is satisfactorily described by an exponential functional relationship in the lowtemperature range. The activation energy of polarization is determined for two temperature sections. Practical value. The research results can be used to study the mechanism of polarization of

  7. Bendable, low-loss Topas fibers for the terahertz frequency range

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Adam, Aurèle J.L.

    2009-01-01

    structure proves that the fiber is single-moded over a wide frequency range, and we see the onset of higher-order modes at high frequencies as well as indication of microporous guiding at low frequencies and high porosity of the fiber. Transmission spectroscopy demonstrates low-loss propagation (

  8. Short-range contacts govern the performance of industry-relevant battery cathodes

    Science.gov (United States)

    Morelly, Samantha L.; Alvarez, Nicolas J.; Tang, Maureen H.

    2018-05-01

    Fundamental understanding of how processing affects composite battery electrode structure and performance is still lacking, especially for industry-relevant electrodes with low fractions of inactive material. This work combines rheology, electronic conductivity measurements, and battery rate capability tests to prove that short-range electronic contacts are more important to cathode rate capability than either ion transport or long-range electronic conductivity. LiNi0.33Mn0.33Co0.33O2, carbon black, and polyvinylidene difluoride in 1-methyl-2-pyrrolidinone represent a typical commercial electrode with films. Improvements in battery rate capability at constant electrode porosity do not correlate to electronic conductivity, but rather show an optimum fraction of free carbon. Simple comparison of rate capability in electrodes with increased total carbon loading (3 wt%) shows improvement for all fractions of free carbon. These results clearly indicate that ion transport cannot be limiting and highlight the critical importance of short-range electronic contacts for controlling battery performance.

  9. Nonlinear parametric phenomena in plasma during radio frequency heating in the ion cyclotron frequency range

    International Nuclear Information System (INIS)

    Stepanov, K.N.

    1996-01-01

    Parametric phenomena in plasma which occur due to varying electric fields with the ion cyclotron frequency are reviewed. Beam-like lower hybrid instability emerges in strong pumping fields provided that the transverse relative velocity of particles is larger than the ion thermal speed (υ Ti ). The resulting turbulence and the following numerous manifestations observed experimentally are addressed. The turbulence may prove important for experiments aimed at plasma production or radio frequency (RF) cleaning of metallic surfaces of vacuum chambers in stellarators, tokamaks and helicon devices. In contrast, for a weak field (U Ti ) the kinetic parametric instabilities of ion cyclotron oscillations arise due to electrons. The issues of the turbulence, mathematical modelling, its role in turbulent heating observed on the torsatron Uragan-3M, decay instabilities associated with ion cyclotron oscillations and the triggering of ion quasimodes are considered. (author)

  10. Extending the Effective Ranging Depth of Spectral Domain Optical Coherence Tomography by Spatial Frequency Domain Multiplexing

    Directory of Open Access Journals (Sweden)

    Tong Wu

    2016-11-01

    Full Text Available We present a spatial frequency domain multiplexing method for extending the imaging depth range of a spectral domain optical coherence tomography (SDOCT system without any expensive device. This method uses two galvo scanners with different pivot-offset distances in two independent reference arms for spatial frequency modulation and multiplexing. The spatial frequency contents corresponding to different depth regions of the sample can be shifted to different frequency bands. The spatial frequency domain multiplexing SDOCT system provides an approximately 1.9-fold increase in the effective ranging depth compared with that of a conventional full-range SDOCT system. The reconstructed images of phantom and biological tissue demonstrate the expected increase in ranging depth. The parameters choice criterion for this method is discussed.

  11. Buried Object Detection Method Using Optimum Frequency Range in Extremely Shallow Underground

    Science.gov (United States)

    Sugimoto, Tsuneyoshi; Abe, Touma

    2011-07-01

    We propose a new detection method for buried objects using the optimum frequency response range of the corresponding vibration velocity. Flat speakers and a scanning laser Doppler vibrometer (SLDV) are used for noncontact acoustic imaging in the extremely shallow underground. The exploration depth depends on the sound pressure, but it is usually less than 10 cm. Styrofoam, wood (silver fir), and acrylic boards of the same size, different size styrofoam boards, a hollow toy duck, a hollow plastic container, a plastic container filled with sand, a hollow steel can and an unglazed pot are used as buried objects which are buried in sand to about 2 cm depth. The imaging procedure of buried objects using the optimum frequency range is given below. First, the standardized difference from the average vibration velocity is calculated for all scan points. Next, using this result, underground images are made using a constant frequency width to search for the frequency response range of the buried object. After choosing an approximate frequency response range, the difference between the average vibration velocity for all points and that for several points that showed a clear response is calculated for the final confirmation of the optimum frequency range. Using this optimum frequency range, we can obtain the clearest image of the buried object. From the experimental results, we confirmed the effectiveness of our proposed method. In particular, a clear image of the buried object was obtained when the SLDV image was unclear.

  12. A current drive by using the fast wave in frequency range higher than two timeslower hybrid resonance frequency on tokamaks

    Directory of Open Access Journals (Sweden)

    Kim Sun Ho

    2017-01-01

    Full Text Available An efficient current drive scheme in central or off-axis region is required for the steady state operation of tokamak fusion reactors. The current drive by using the fast wave in frequency range higher than two times lower hybrid resonance (w>2wlh could be such a scheme in high density, high temperature reactor-grade tokamak plasmas. First, it has relatively higher parallel electric field to the magnetic field favorable to the current generation, compared to fast waves in other frequency range. Second, it can deeply penetrate into high density plasmas compared to the slow wave in the same frequency range. Third, parasitic coupling to the slow wave can contribute also to the current drive avoiding parametric instability, thermal mode conversion and ion heating occured in the frequency range w<2wlh. In this study, the propagation boundary, accessibility, and the energy flow of the fast wave are given via cold dispersion relation and group velocity. The power absorption and current drive efficiency are discussed qualitatively through the hot dispersion relation and the polarization. Finally, those characteristics are confirmed with ray tracing code GENRAY for the KSTAR plasmas.

  13. Coherent laser radar with dual-frequency Doppler estimation and interferometric range detection

    NARCIS (Netherlands)

    Onori, D.; Scotti, F.; Laghezza, F.; Scaffardi, M.; Bogoni, A.

    2016-01-01

    The concept of a coherent interferometric dual frequency laser radar, that measures both the target range and velocity, is presented and experimentally demonstrated. The innovative architecture combines the dual frequency lidar concept, allowing a precise and robust Doppler estimation, with the

  14. GaN-based High Power High Frequency Wide Range LLC Resonant Converter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SET Group will design, build and demonstrate a Gallium Nitride (GaN) based High Power High Frequency Wide Range LLC Resonant Converter capable of handling high power...

  15. Modal spectral analysis of piping: Determination of the significant frequency range

    International Nuclear Information System (INIS)

    Geraets, L.H.

    1981-01-01

    This paper investigates the influence of the number of modes on the response of a piping system in a dynamic modal spectral analysis. It shows how the analysis can be limited to a specific frequency range of the pipe (independent of the frequency range of the response spectrum), allowing cost reduction without loss in accuracy. The 'missing mass' is taken into account through an original technique. (orig./HP)

  16. Electron-beam buncher to operate over the frequency range 1-4 GHz

    International Nuclear Information System (INIS)

    Goldberg, D.A.; Arthur, A.A.; Flood, W.S.; Voelker, F.

    1983-03-01

    We present a description of an electron buncher to be installed in the terminal of a Van de Graaff, which is to produce a modulated beam over the frequency range 1-4 GHz. The modulator geometry has been optimized so that the modulation amplitude should be nearly constant over the frequency ranges 1-2 GHz and 2-4 GHz. Preliminary results indicate the device works as predicted

  17. Thrombolysis using multi-frequency high intensity focused ultrasound at MHz range: an in vitro study

    International Nuclear Information System (INIS)

    Suo, Dingjie; Guo, Sijia; Jiang, Xiaoning; Jing, Yun; Lin, Weili

    2015-01-01

    High intensity focused ultrasound (HIFU) based thrombolysis has emerged as a promising drug-free treatment approach for ischemic stroke. The large amount of acoustic power required by this approach, however, poses a critical challenge to the future clinical translation. In this study, multi-frequency acoustic waves at MHz range (near 1.5 MHz) were introduced as HIFU excitations to reduce the required power for treatment as well as the treatment time. In vitro bovine blood clots weighing around 150 mg were treated by single-frequency and multi-frequency HIFU. The pulse length was 2 ms for all experiments except the ones where the duty cycle was changed. It was found that dual-frequency thrombolysis efficiency was statistically better than single-frequency under the same acoustic power and excitation condition. When varying the acoustic power but fixing the duty cycle at 5%, it was found that dual-frequency ultrasound can save almost 30% power in order to achieve the same thrombolysis efficiency. In the experiment where the duty cycle was increased from 0.5% to 10%, it was shown that dual-frequency ultrasound can achieve the same thrombolysis efficiency with only half of the duty cycle of single-frequency. Dual-frequency ultrasound could also accelerate the thrombolysis by a factor of 2–4 as demonstrated in this study. No significant differences were found between dual-frequencies with different frequency differences (0.025, 0.05, and 0.1 MHz) and between dual-frequency and triple-frequency. The measured cavitation doses of dual-frequency and triple-frequency excitations were at about the same level but both were significantly higher than that of single-frequency. (paper)

  18. Outdoor stocking density in free-range laying hens: radio-frequency identification of impacts on range use.

    Science.gov (United States)

    Campbell, D L M; Hinch, G N; Dyall, T R; Warin, L; Little, B A; Lee, C

    2017-01-01

    The number and size of free-range laying hen (Gallus gallus domesticus) production systems are increasing within Australia in response to consumer demand for perceived improvement in hen welfare. However, variation in outdoor stocking density has generated consumer dissatisfaction leading to the development of a national information standard on free-range egg labelling by the Australian Consumer Affairs Ministers. The current Australian Model Code of Practice for Domestic Poultry states a guideline of 1500 hens/ha, but no maximum density is set. Radio-frequency identification (RFID) tracking technology was used to measure daily range usage by individual ISA Brown hens housed in six small flocks (150 hens/flock - 50% of hens tagged), each with access to one of three outdoor stocking density treatments (two replicates per treatment: 2000, 10 000, 20 000 hens/ha), from 22 to 26, 27 to 31 and 32 to 36 weeks of age. There was some variation in range usage across the sampling periods and by weeks 32 to 36 individual hens from the lowest stocking density on average used the range for longer each day (Prange with 2% of tagged hens in each treatment never venturing outdoors and a large proportion that accessed the range daily (2000 hens/ha: 80.5%; 10 000 hens/ha: 66.5%; 20 000 hens/ha: 71.4%). On average, 38% to 48% of hens were seen on the range simultaneously and used all available areas of all ranges. These results of experimental-sized flocks have implications for determining optimal outdoor stocking densities for commercial free-range laying hens but further research would be needed to determine the effects of increased range usage on hen welfare.

  19. Integrated, Reactor Relevant Solutions for Lower Hybrid Range of Frequencies Actuators

    Science.gov (United States)

    Shiraiwa, S.; Bonoli, P. T.; Lin, Y.; Wallace, G. M.; Wukitch, S. J.

    2017-10-01

    RF (radiofrequency) actuators with high system efficiency (wall-plug to plasma) and ability for continuous operation have long be recognized as essential tools for realizing a steady state tokamak. A number of physics and technological challenges to utilization remain including current drive efficiency and location, efficient coupling, and impurity contamination. In a reactor environment, plasma material interaction (PMI) issues associated with coupling structures are similar to the first wall and have been identified as a potential show-stopper. High field side (HFS) launch of LHRF power represents an integrated solution that both improves core wave physics and mitigates PMI/coupling issues. For HFS LHRF, wave penetration is vastly improves because wave accessibility scales as 1/B allowing for launching the wave at lower n|| (parallel refractive index). The lower n|| penetrate to higher electron temperature resulting in higher current drive efficiency (1/n||2). HFS RF launch also provides for a means to dramatically improve launcher robustness in a reactor environment. On the HFS, the SOL is quiescent; local density profile is steep and controlled through magnetic shape; fast particle, neutron, turbulent heat and particle fluxes are eliminated or minim Work supported by the U.S. DoE, Office of Science, Office of Fusion Energy Sciences, User Facility Alcator C-Mod under DE-FC02-99ER54512 and US DoE Contract No. DE-FC02-01ER54648 under a Scientific Discovery through Advanced Computing Initiative.

  20. Shifts in diversification rates and host jump frequencies shaped the diversity of host range among Sclerotiniaceae fungal plant pathogens.

    Science.gov (United States)

    Navaud, Olivier; Barbacci, Adelin; Taylor, Andrew; Clarkson, John P; Raffaele, Sylvain

    2018-03-01

    The range of hosts that a parasite can infect in nature is a trait determined by its own evolutionary history and that of its potential hosts. However, knowledge on host range diversity and evolution at the family level is often lacking. Here, we investigate host range variation and diversification trends within the Sclerotiniaceae, a family of Ascomycete fungi. Using a phylogenetic framework, we associate diversification rates, the frequency of host jump events and host range variation during the evolution of this family. Variations in diversification rate during the evolution of the Sclerotiniaceae define three major macro-evolutionary regimes with contrasted proportions of species infecting a broad range of hosts. Host-parasite cophylogenetic analyses pointed towards parasite radiation on distant hosts long after host speciation (host jump or duplication events) as the dominant mode of association with plants in the Sclerotiniaceae. The intermediate macro-evolutionary regime showed a low diversification rate, high frequency of duplication events and the highest proportion of broad host range species. Our findings suggest that the emergence of broad host range fungal pathogens results largely from host jumps, as previously reported for oomycete parasites, probably combined with low speciation rates. These results have important implications for our understanding of fungal parasites evolution and are of particular relevance for the durable management of disease epidemics. © 2018 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  1. Spontaneous otoacoustic emissions, threshold microstructure, and psychophysical tuning over a wide frequency range in humansa

    Science.gov (United States)

    Baiduc, Rachael R.; Lee, Jungmee; Dhar, Sumitrajit

    2014-01-01

    Hearing thresholds have been shown to exhibit periodic minima and maxima, a pattern known as threshold microstructure. Microstructure has previously been linked to spontaneous otoacoustic emissions (SOAEs) and normal cochlear function. However, SOAEs at high frequencies (>4 kHz) have been associated with hearing loss or cochlear pathology in some reports. Microstructure would not be expected near these high-frequency SOAEs. Psychophysical tuning curves (PTCs), the expression of frequency selectivity, may also be altered by SOAEs. Prior comparisons of tuning between ears with and without SOAEs demonstrated sharper tuning in ears with emissions. Here, threshold microstructure and PTCs were compared at SOAE frequencies ranging between 1.2 and 13.9 kHz using subjects without SOAEs as controls. Results indicate: (1) Threshold microstructure is observable in the vicinity of SOAEs of all frequencies; (2) PTCs are influenced by SOAEs, resulting in shifted tuning curve tips, multiple tips, or inversion. High frequency SOAEs show a greater effect on PTC morphology. The influence of most SOAEs at high frequencies on threshold microstructure and PTCs is consistent with those at lower frequencies, suggesting that high-frequency SOAEs reflect the same cochlear processes that lead to SOAEs at lower frequencies. PMID:24437770

  2. Study on The Extended Range Weather Forecast of Low Frequency Signal Based on Period Analysis Method

    Science.gov (United States)

    Li, X.

    2016-12-01

    Although many studies have explored the MJO and its application for weather forecasting, low-frequency oscillation has been insufficiently studied for the extend range weather forecasting over middle and high latitudes. In China, low-frequency synoptic map is a useful tool for meteorological operation department to forecast extend range weather. It is therefore necessary to develop objective methods to serve the need for finding low-frequency signal, interpretation and application of this signal in the extend range weather forecasting. In this paper, method of Butterworth band pass filter was applied to get low-frequency height field at 500hPa from 1980 to 2014 by using NCEP/NCAR daily grid data. Then period analysis and optimal subset regression methods were used to process the low frequency data of 150 days before the first forecast day and extend the low frequency signal of 500hPa low-frequency high field to future 30 days in the global from June to August during 2011-2014. Finally, the results were test. The main results are as follows: (1) In general, the fitting effect of low frequency signals of 500hPa low-frequency height field by period analysis in the northern hemisphere was better than that in the southern hemisphere, and was better in the low latitudes than that in the high latitudes. The fitting accuracy gradually reduced with the increase of forecast time length, which tended to be stable during the late forecasting period. (2) The fitting effects over the 6 key regions in China showed that except filtering result over Xinjiang area in the first 10 days and 30 days, filtering results over the other 5 key regions throughout the whole period have passed reliability test with level more than 95%. (3) The center and scope of low and high low frequency systems can be fitted well by using the methods mentioned above, which is consist with the corresponding use of the low-frequency synoptic map for the prediction of the extended period. Application of the

  3. RF-field generation in wide frequency range by electron beam

    International Nuclear Information System (INIS)

    Bogdanovich, B.; Nesterovich, A.; Minaev, S.

    1996-01-01

    A simple device for generating powerful RF oscillations in the frequency range of 100-250 MHz is considered. The two-gaps cavity is based on the quarter-wavelength coaxial line loaded by drift tubes. Frequency tuning is accomplished by using the movable shorting plunger. A permanent electron beam being modulated at the first gap return the energy at the second one. The additional tube with the permanent decelerating potential, introduced into the main drift tube, allows to decrease the drift tube length and keep the excitation conditions in frequency tuning. Both autogeneration and amplification modes are under consideration. RF-parameters of the cavity and experimental results are described. (author)

  4. Note: Digital laser frequency auto-locking for inter-satellite laser ranging.

    Science.gov (United States)

    Luo, Yingxin; Li, Hongyin; Yeh, Hsien-Chi

    2016-05-01

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  5. Note: Digital laser frequency auto-locking for inter-satellite laser ranging

    International Nuclear Information System (INIS)

    Luo, Yingxin; Yeh, Hsien-Chi; Li, Hongyin

    2016-01-01

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  6. Note: Digital laser frequency auto-locking for inter-satellite laser ranging

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yingxin; Yeh, Hsien-Chi, E-mail: yexianji@mail.hust.edu.cn [MOE Key Laboratory of Fundamental Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Li, Hongyin [MOE Key Laboratory of Fundamental Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-05-15

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  7. Modelling of the dual frequency capacitive sheath in the intermediate pressure range

    International Nuclear Information System (INIS)

    Boyle, P C; Robiche, J; Turner, M M

    2004-01-01

    The nonlinearity of the plasma sheath in dual frequency capacitively coupled reactors is investigated for frequencies well above the ion plasma frequency. This work focuses on the behaviour of the voltage and the sheath width with respect to the driving current source and the collisionality regime. For typical plasma processing applications, the gas pressure ranges from a few milliTorrs to hundreds of milliTorrs, and the ion dynamics span different collisional regimes. To describe these different ion dynamics, we have used a collisionless model and a variable mobility model. The sheath widths and the voltages obtained from these two models have then been compared

  8. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, F

    2007-03-14

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  9. Ohmic heating of peaches in the wide range of frequencies (50 Hz to 1 MHz).

    Science.gov (United States)

    Shynkaryk, Mykola V; Ji, Taehyun; Alvarez, Valente B; Sastry, Sudhir K

    2010-09-01

    The ohmic heating (OH) rate of peaches was studied at fixed electric field strength of 60 V.cm⁻¹, square-shaped instant reversal bipolar pulses, and frequencies varying within 50 Hz to 1 MHz. Thermal damage of tissue was evaluated from electrical admittivity. It showed that the time for half disruption (τ(T)) of tissue was required more than 10 h at temperatures below 40 °C. However, cellular thermal disruption occurred almost instantly (τ(T) 90 °C). Electrical conductivity σ(o) and admittivity σ(o)* of tissue at T(o)= 0 °C and their temperature coefficients (m, m*) were calculated. For freeze-thawed tissues, σ and σ* as well as m and m* were nearly indifferent to the frequency. However, for the intact tissue, both σ(o), σ(o)* and m, m* were frequency dependent. For freeze-thawed product, the power factor (P) was approximately equal to 1 and indifferent to the frequency and temperature. On the other hand, strong frequency dependence was observed for intact tissue with the minimum P approximately equal to 0.68 in the range of tens of kHz. The time required to reach a target temperature t(f) was evaluated. The t(f) increased with frequency up to the middle of the range of tens of kHz and thereafter continuously decreased. Samples exposed to the low-frequency electric field demonstrated faster electro-thermal damage rates. The textural relaxation data supported more intense damage kinetics at low-frequency OH. It has been demonstrated that a combination of high-frequency OH with pasteurization at moderate temperature followed by rapid cooling minimizes texture degradation of peach tissue. In this study, we investigated the electric field frequency effect on the rate of OH of peaches. It was shown that the time required for reaching the target temperature is strongly dependent upon the frequency. Samples exposed to low-frequency OH demonstrated higher electro-thermal damage rates. It has been shown that the combination of high-frequency OH with

  10. A Wide Lock-Range Referenceless CDR with Automatic Frequency Acquisition

    OpenAIRE

    Seon-Kyoo Lee; Young-Sang Kim; Hong-June Park; Jae-Yoon Sim

    2011-01-01

    A wide lock-range referenceless CDR circuit is proposed with an automatic tracking of data rate. For efficient frequency acquisition, a DLL-based loop is used with a simple phase/frequency detector to extract 1-bit period of input data stream. The CDR, implemented in a 65 nm CMOS, shows a lock range of 650 Mb/s-to-8 Gb/s and BER of less than 10-12 at 8 Gb/s with low power consumption.

  11. A Wide Lock-Range Referenceless CDR with Automatic Frequency Acquisition

    Directory of Open Access Journals (Sweden)

    Seon-Kyoo Lee

    2011-01-01

    Full Text Available A wide lock-range referenceless CDR circuit is proposed with an automatic tracking of data rate. For efficient frequency acquisition, a DLL-based loop is used with a simple phase/frequency detector to extract 1-bit period of input data stream. The CDR, implemented in a 65 nm CMOS, shows a lock range of 650 Mb/s-to-8 Gb/s and BER of less than 10-12 at 8 Gb/s with low power consumption.

  12. Composite Broadcasting and Ranging via a Satellite Dual-Frequency MPPSK System

    Directory of Open Access Journals (Sweden)

    Yu Yao

    2013-01-01

    Full Text Available Since digital video broadcasting via satellite (DVB-S signals are “inefficient”, regarding the amount of information they convey on the bandwidth they occupy, a joint broadcasting and ranging system would constitute a unique platform for future digital video broadcasting satellite services effecting the essential tasks of satellite navigation system and direct to home (DTH services, in terms of both spectrum efficiency and cost effectiveness. In this paper, the design of dual frequency M-ary position phase shift keying (MPPSK system which is suitable for, respectively, performing both data transmission and range measurement is proposed. The approach is based on MPPSK modulation waveforms utilized in digital video broadcasting. In particular, requirements that allow for employing such signals for range measurements with high accuracy and high range are investigated. Also, the relationship between the frequency difference of dual frequency MPPSK system and range accuracy is discussed. Moreover, the selection of MPPSK modulation parameter for data rate and ranging is considered. In addition to theoretical considerations, the paper presents system simulations and measurement results of new systems, demonstrating the high spectral utilization of integrated broadcasting and ranging applications.

  13. Understanding and Utilizing Waveguide Invariant Range-frequency Striations in Ocean Acoustic Waveguides

    Science.gov (United States)

    2011-02-01

    providing often- needed comic relief. Mike Benjamin for his career guidance and keeping LAMSS down-to-earth. Joe Curcio for being such a great travel...of about 1% due to receiver motion . Such a shift may cause range estimate errors of about 1%, which is negligible compared to the overall expected...most cases the Doppler effect due to source/receiver motion has little effect on range-frequency striations. It also brief y mentions how to account

  14. Rolling estimations of long range dependence volatility for high frequency S&P500 index

    Science.gov (United States)

    Cheong, Chin Wen; Pei, Tan Pei

    2015-10-01

    This study evaluates the time-varying long range dependence behaviors of the S&P500 volatility index using the modified rescaled adjusted range (R/S) statistic. For better computational result, a high frequency rolling bipower variation realized volatility estimates are used to avoid possible abrupt jump. The empirical analysis findings allow us to understand better the informationally market efficiency before and after the subprime mortgage crisis.

  15. Implementation of acoustic demultiplexing with membrane-type metasurface in low frequency range

    Science.gov (United States)

    Chen, Xing; Liu, Peng; Hou, Zewei; Pei, Yongmao

    2017-04-01

    Wavelength division multiplexing technology, adopted to increase the information density, plays a significant role in optical communication. However, in acoustics, a similar function can be hardly implemented due to the weak dispersion in natural acoustic materials. Here, an acoustic demultiplexer, based on the concept of metasurfaces, is proposed for splitting acoustic waves and propagating along different trajectories in a low frequency range. An acoustic metasurface, containing multiple resonant units, is designed with various phase profiles for different frequencies. Originating from the highly dispersive properties, the resonant units are independent and merely work in the vicinity of their resonant frequencies. Therefore, by combing multiple resonant units appropriately, the phenomena of anomalous reflection, acoustic focusing, and acoustic wave bending can occur in different frequencies. The proposed acoustic demultiplexer has advantages on the subwavelength scale and the versatility in wave control, providing a strategy for separating acoustic waves with different Fourier components.

  16. Real time analysis of electromagnetic radiation in a very wide frequency range

    International Nuclear Information System (INIS)

    Peralta, J.A.; Reyes L, P.; Yepez, E.

    2001-01-01

    In this work, we present an electronic apparatus that facilitates the monitoring and analysis of electromagnetic radiation in a very wide frequency range. The device is a combination of real and virtual instruments, taking advantage of new hardware and software; the measurable range of frequencies depends on the speed of an analog/digital converter, reaching tens of Megahertz. The device has been successfully used to monitor the environmental electromagnetic radiation at very low frequency, a very useful parameter in the research of electromagnetic precursors of earthquakes. The apparatus is a new configuration and has advantages with respect to those previously used: when the attached computer is fast, Fourier analysis can be done in real time, can display simultaneously several bands, the digitized data allow a variety of methods of analysis, and the apparatus is very cheap. (Author)

  17. Real time analysis of electromagnetic radiation in a very wide frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, J.A.; Reyes L, P.; Yepez, E. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, Edificio 9, U.P. Adolfo Lopez Mateos, Zacatenco, 07738 Mexico D.F. (Mexico)

    2001-07-01

    In this work, we present an electronic apparatus that facilitates the monitoring and analysis of electromagnetic radiation in a very wide frequency range. The device is a combination of real and virtual instruments, taking advantage of new hardware and software; the measurable range of frequencies depends on the speed of an analog/digital converter, reaching tens of Megahertz. The device has been successfully used to monitor the environmental electromagnetic radiation at very low frequency, a very useful parameter in the research of electromagnetic precursors of earthquakes. The apparatus is a new configuration and has advantages with respect to those previously used: when the attached computer is fast, Fourier analysis can be done in real time, can display simultaneously several bands, the digitized data allow a variety of methods of analysis, and the apparatus is very cheap. (Author)

  18. Computerized J-H loop tracer for soft magnetic thick films in the audio frequency range

    Directory of Open Access Journals (Sweden)

    Loizos G.

    2014-07-01

    Full Text Available A computerized J-H loop tracer for soft magnetic thick films in the audio frequency range is described. It is a system built on a PXI platform combining PXI modules for control signal generation and data acquisition. The physiscal signals are digitized and the respective data strems are processed, presented and recorded in LabVIEW 7.0.

  19. Numerical modelisation of RF waves in the ion cyclotron range of frequency for Tokamak plasmas

    International Nuclear Information System (INIS)

    Edery, D.; Picq, H.; Samain, A.; Gambier, D.J.

    1987-12-01

    The purpose of this paper is to present the numerical code ALCYON developed to compute the RF field structure in the ion cyclotron range of frequencies. The code handles fundamental and second harmonic heating while the mode conversion onto modes of decreasing wavelength is simulated by a selective power absorption on slow waves when their wavelength reaches the mesh size

  20. Surface impedance of superconductors in wide frequency ranges for wake field calculations

    International Nuclear Information System (INIS)

    Davidovskii, V.G.

    2006-01-01

    The problem of the surface impedance of superconductors in wide frequency ranges for calculations of wake fields, generated by bunches of charged particles moving axially inside a metallic vacuum chambers, is solved. The case of specular electron reflection at the superconductor surface is considered. The expression for the surface impedance of superconductors suitable for numerical computation is derived [ru

  1. Tuning Range Optimization of a Planar Inverted F Antenna for LTE Low Frequency Bands

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Pelosi, Mauro; Franek, Ondrej

    2011-01-01

    This paper presents a Planar Inverted F Antenna (PIFA) tuned with a fixed capacitor to the low frequency bands supported by the Long Term Evolution (LTE) technology. The tuning range is investigated and optimized with respect to the bandwidth and the efficiency of the resulting antenna. Simulatio...... and mock-ups are presented....

  2. Hydrothermal germination models: Improving experimental efficiency by limiting data collection to the relevant hydrothermal range

    Science.gov (United States)

    Hydrothermal models used to predict germination response in the field are usually parameterized with data from laboratory experiments that examine the full range of germination response to temperature and water potential. Inclusion of low water potential and high and low-temperature treatments, how...

  3. Research on the range side lobe suppression method for modulated stepped frequency radar signals

    Science.gov (United States)

    Liu, Yinkai; Shan, Tao; Feng, Yuan

    2018-05-01

    The magnitude of time-domain range sidelobe of modulated stepped frequency radar affects the imaging quality of inverse synthetic aperture radar (ISAR). In this paper, the cause of high sidelobe in modulated stepped frequency radar imaging is analyzed first in real environment. Then, the chaos particle swarm optimization (CPSO) is used to select the amplitude and phase compensation factors according to the minimum sidelobe criterion. Finally, the compensated one-dimensional range images are obtained. Experimental results show that the amplitude-phase compensation method based on CPSO algorithm can effectively reduce the sidelobe peak value of one-dimensional range images, which outperforms the common sidelobe suppression methods and avoids the coverage of weak scattering points by strong scattering points due to the high sidelobes.

  4. Precision improvement of frequency-modulated continuous-wave laser ranging system with two auxiliary interferometers

    Science.gov (United States)

    Shi, Guang; Wang, Wen; Zhang, Fumin

    2018-03-01

    The measurement precision of frequency-modulated continuous-wave (FMCW) laser distance measurement should be proportional to the scanning range of the tunable laser. However, the commercial external cavity diode laser (ECDL) is not an ideal tunable laser source in practical applications. Due to the unavoidable mode hopping and scanning nonlinearity of the ECDL, the measurement precision of FMCW laser distance measurements can be substantially affected. Therefore, an FMCW laser ranging system with two auxiliary interferometers is proposed in this paper. Moreover, to eliminate the effects of ECDL, the frequency-sampling method and mode hopping influence suppression method are employed. Compared with a fringe counting interferometer, this FMCW laser ranging system has a measuring error of ± 20 μm at the distance of 5.8 m.

  5. Frequency and clinical relevance of human bocavirus infection in acute exacerbations of chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Felix C Ringshausen

    2009-02-01

    Full Text Available Felix C Ringshausen1, Ai-Yui M Tan1, Tobias Allander2, Irmgard Borg1, Umut Arinir1, Juliane Kronsbein1, Barbara M Hauptmeier1, Gerhard Schultze-Werninghaus1, Gernot Rohde11Clinical Research Group “Significance of viral infections in chronic respiratory diseases of children and adults,” University Hospital Bergmannsheil, Department of Internal Medicine III–Pneumology, Allergology and Sleep Medicine, Bochum, Germany; 2Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, and Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, SwedenObjective: Human bocavirus (HBoV is a recently discovered parvovirus associated with acute respiratory tract infections in children. The objective of the present study was to determine the frequency and clinical relevance of HBoV infection in adult patients with acute exacerbation of chronic obstructive pulmonary disease (AE-COPD.Methods: We retrospectively tested 212 COPD patients, 141 (66.5% with AE-COPD and 71 (33.5% with stable disease, of whom nasal lavage and induced sputum had been obtained for the presence of HBoV deoxyribonucleic acid (DNA. The specificity of positive polymerase chain reaction results was confirmed by sequencing.Results: Two hundred two of 212 patients for whom PCR results were available both for nasal lavage and induced sputum samples were eligible for data analysis. HBoV DNA was detected in three patients (1.5%. Of those, only one patient had AE-COPD. Thus, the frequency of HBoV infection demonstrated to be low in both AE-COPD (0.8% and stable COPD (2.9%. HBoV was found in two sputum and one nasal lavage sample in different patients, respectively. Sequencing revealed >99% sequence identity with the reference strain.Conclusion: HBoV detection was infrequent. Since we detected HBoV in both upper and lower respiratory tract specimens and in AE-COPD as well as stable disease, a major role of HBoV infection in adults with AE-COPD is unlikely

  6. An optimal frequency range for assessing the pressure reactivity index in patients with traumatic brain injury.

    Science.gov (United States)

    Howells, Tim; Johnson, Ulf; McKelvey, Tomas; Enblad, Per

    2015-02-01

    The objective of this study was to identify the optimal frequency range for computing the pressure reactivity index (PRx). PRx is a clinical method for assessing cerebral pressure autoregulation based on the correlation of spontaneous variations of arterial blood pressure (ABP) and intracranial pressure (ICP). Our hypothesis was that optimizing the methodology for computing PRx in this way could produce a more stable, reliable and clinically useful index of autoregulation status. The patients studied were a series of 131 traumatic brain injury patients. Pressure reactivity indices were computed in various frequency bands during the first 4 days following injury using bandpass filtering of the input ABP and ICP signals. Patient outcome was assessed using the extended Glasgow Outcome Scale (GOSe). The optimization criterion was the strength of the correlation with GOSe of the mean index value over the first 4 days following injury. Stability of the indices was measured as the mean absolute deviation of the minute by minute index value from 30-min moving averages. The optimal index frequency range for prediction of outcome was identified as 0.018-0.067 Hz (oscillations with periods from 55 to 15 s). The index based on this frequency range correlated with GOSe with ρ=-0.46 compared to -0.41 for standard PRx, and reduced the 30-min variation by 23%.

  7. The relationship between brightness temperature and soil moisture. Selection of frequency range for microwave remote sensing

    International Nuclear Information System (INIS)

    Rao, K.S.; Chandra, G.; Rao, P.V.N.

    1987-01-01

    The analysis of brightness temperature data acquired from field and aircraft experiments demonstrates a linear relationship between soil moisture and brightness temperature. However, the analysis of brightness temperature data acquired by the Skylab radiometer demonstrates a non-linear relationship between soil moisture and brightness temperature. In view of the above and also because of recent theoretical developments for the calculation of the dielectric constant and brightness temperature under varying soil moisture profile conditions, an attempt is made to study the theoretical relationship between brightness temperature and soil moisture as a function of frequency. Through the above analysis, the appropriate microwave frequency range for soil moisture studies is recommended

  8. An impedance bridge measuring the capacitance ratio in the high frequency range up to 1 MHz

    International Nuclear Information System (INIS)

    Kim, Dan Bee; Lee, Hyung Kew; Kim, Wan-Seop

    2017-01-01

    This paper describes a 2-terminal-pair impedance bridge, measuring the capacitance ratio in the high frequency range up to 1 MHz. The bridge was configured with two voltage sources and a phase control unit which enabled the bridge balance by synchronizing the voltage sources with an enhanced phase resolution. Without employing the transformers such as inductive voltage divider, injection and detection transformers, etc, the bridge system is quite simple to set up, and the balance procedure is quick and easy. Using this dual-source coaxial bridge, the 1:1 and 10:1 capacitance ratios were measured with 1 pF–1 nF capacitors in the frequency range from 1 kHz to 1 MHz. The measurement values obtained by the dual-source bridge were then compared with reference values measured using a commercial precision capacitance bridge of AH2700A, the Z -matrix method developed by ourselves, and the 4-terminal-pair coaxial bridge by the Czech Metrological Institute. All the measurements agreed within the reference uncertainty range of an order of 10 −6 –10 −5 , proving the bridge ability as a trustworthy tool for measuring the capacitance ratio in the high frequency range. (paper)

  9. Electrodynamic properties of porous PZT-Pt films at terahertz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Komandin, Gennady A.; Porodinkov, Oleg E.; Spektor, Igor E.; Volkov, Alexander A. [Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Vorotilov, Konstantin A.; Seregin, Dmitry S.; Sigov, Alexander S. [Moscow Technological University (MIREA), Moscow (Russian Federation)

    2017-01-15

    Electrodynamics of Si-SiO{sub 2}-TiO{sub 2}-Pt-PZT heterostructures is studied in the frequency range from 5 to 5000 cm{sup -1} by monochromatic BWO (backward wave oscillator) and infrared Fourier-transform spectroscopy techniques to derive the dielectric characteristics of the sol-gel porous ferroelectric PbZr{sub 0.48}Ti{sub 0.52}O{sub 3} films. Broad frequency band dielectric response of PZT films with different density is constructed using the oscillator dispersion models. The main contribution to the film permittivity is found to form at frequencies below 100 cm{sup -1} depending strongly and non-linearly on the film medium density. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Sustained Spatial Attention to Vibrotactile Stimulation in the Flutter Range: Relevant Brain Regions and Their Interaction

    Science.gov (United States)

    Goltz, Dominique; Pleger, Burkhard; Thiel, Sabrina; Villringer, Arno; Müller, Matthias M.

    2013-01-01

    The present functional magnetic resonance imaging (fMRI) study was designed to get a better understanding of the brain regions involved in sustained spatial attention to tactile events and to ascertain to what extent their activation was correlated. We presented continuous 20 Hz vibrotactile stimuli (range of flutter) concurrently to the left and right index fingers of healthy human volunteers. An arrow cue instructed subjects in a trial-by-trial fashion to attend to the left or right index finger and to detect rare target events that were embedded in the vibrotactile stimulation streams. We found blood oxygen level-dependent (BOLD) attentional modulation in primary somatosensory cortex (SI), mainly covering Brodmann area 1, 2, and 3b, as well as in secondary somatosensory cortex (SII), contralateral to the to-be-attended hand. Furthermore, attention to the right (dominant) hand resulted in additional BOLD modulation in left posterior insula. All of the effects were caused by an increased activation when attention was paid to the contralateral hand, except for the effects in left SI and insula. In left SI, the effect was related to a mixture of both a slight increase in activation when attention was paid to the contralateral hand as well as a slight decrease in activation when attention was paid to the ipsilateral hand (i.e., the tactile distraction condition). In contrast, the effect in left posterior insula was exclusively driven by a relative decrease in activation in the tactile distraction condition, which points to an active inhibition when tactile information is irrelevant. Finally, correlation analyses indicate a linear relationship between attention effects in intrahemispheric somatosensory cortices, since attentional modulation in SI and SII were interrelated within one hemisphere but not across hemispheres. All in all, our results provide a basis for future research on sustained attention to continuous vibrotactile stimulation in the range of flutter

  11. Magnetic losses of commercial REBCO coated conductors in the low frequency range

    Science.gov (United States)

    De Marzi, G.; Iannone, G.; Gambardella, U.

    2018-05-01

    We have investigated the frequency dependence of the magnetic losses of different 2 G commercial REBCO coated-conductor tapes in the low frequency range ∼1–10 mHz of applied magnetic field at 5 and 77 K. We explored high field range, well above the penetration field, with fields applied perpendicularly to the flat surface. We found that the in-field hysteresis losses increase with increasing frequencies in all the investigated high-temperature superconductor (HTS) tapes, following a power-law dependence. An electromagnetic 2D finite element method model, based on H-formulation, has also been implemented, in which the frequency dependence of the hysteretic loss is computed taking into account the measured power-law E(J) characteristic for the electric field, and the experimental J c(B). Experimental and numerical findings are in very good agreement, so an extrapolation to higher ramp rate values is possible, thus providing a useful basis for the assessment of the hysteresis losses in fusion and accelerator HTS magnets.

  12. Structure and dielectric properties in the radio frequency range of polymer composites based on vanadium dioxide

    Directory of Open Access Journals (Sweden)

    Kolbunov V.R.

    2015-06-01

    Full Text Available Polymer composites with active fillers are recently considered to be promising materials for the design of new functional devices with controllable properties and are intensively investigated. Dielectric studies are one of the most effective methods for studying structural features and mechanisms of conductivity formation for this type of two-component systems. The paper presents research results of the dielectric characteristics in the range of radio frequency of 50 kHz — 10 MHz and temperature range of 30—60°C of polyethylene composites of vanadium dioxide with different volume fractions of filler. Two dispersion areas were found: a high-frequency area caused by the Maxwell charge separation on the boundaries of the polyethylene matrix — conductive filler of VI2 crystallites, and a low frequency area associated with the presence of the transition layer at this boundary. The relative permittivity of the composite has a tendency to a decrease in absolute value with increasing temperature. The analysis of the low-frequency dependence of the dielectric constant of the value of the filler’s volume fraction revealed that the investigated composite belongs to two-component statistical mixtures with a transition layer between the components.

  13. Design of a High Linearity Four-Quadrant Analog Multiplier in Wideband Frequency Range

    Directory of Open Access Journals (Sweden)

    Abdul kareem Mokif Obais

    2017-05-01

    Full Text Available In this paper, a voltage mode four quadrant analog multiplier in the wideband frequency rangeis designed using a wideband operational amplifier (OPAMP and squaring circuits. The wideband OPAMP is designed using 10 identical NMOS transistorsand operated with supply voltages of ±12V. Two NMOS transistors and two wideband OPAMP are utilized in the design of the proposed squaring circuit. All the NMOS transistors are based on 0.35µm NMOStechnology. The multiplier has input and output voltage ranges of ±10 V, high range of linearity from -10 V to +10 V, and cutoff frequency of about 5 GHz. The proposed multiplier is designed on PSpice in Orcad 16.6

  14. Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems

    Energy Technology Data Exchange (ETDEWEB)

    Yin Jiangwei; Li Ning; Zheng Renliang; Li Wei; Ren Junyan, E-mail: lining@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2009-05-01

    This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 mum RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 x 0.28 mm{sup 2}. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

  15. Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems

    International Nuclear Information System (INIS)

    Yin Jiangwei; Li Ning; Zheng Renliang; Li Wei; Ren Junyan

    2009-01-01

    This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 μm RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 x 0.28 mm 2 . The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

  16. Relevance feature selection of modal frequency-ambient condition pattern recognition in structural health assessment for reinforced concrete buildings

    Directory of Open Access Journals (Sweden)

    He-Qing Mu

    2016-08-01

    Full Text Available Modal frequency is an important indicator for structural health assessment. Previous studies have shown that this indicator is substantially affected by the fluctuation of ambient conditions, such as temperature and humidity. Therefore, recognizing the pattern between modal frequency and ambient conditions is necessary for reliable long-term structural health assessment. In this article, a novel machine-learning algorithm is proposed to automatically select relevance features in modal frequency-ambient condition pattern recognition based on structural dynamic response and ambient condition measurement. In contrast to the traditional feature selection approaches by examining a large number of combinations of extracted features, the proposed algorithm conducts continuous relevance feature selection by introducing a sophisticated hyperparameterization on the weight parameter vector controlling the relevancy of different features in the prediction model. The proposed algorithm is then utilized for structural health assessment for a reinforced concrete building based on 1-year daily measurements. It turns out that the optimal model class including the relevance features for each vibrational mode is capable to capture the pattern between the corresponding modal frequency and the ambient conditions.

  17. Frequency-Modulated, Continuous-Wave Laser Ranging Using Photon-Counting Detectors

    Science.gov (United States)

    Erkmen, Baris I.; Barber, Zeb W.; Dahl, Jason

    2014-01-01

    Optical ranging is a problem of estimating the round-trip flight time of a phase- or amplitude-modulated optical beam that reflects off of a target. Frequency- modulated, continuous-wave (FMCW) ranging systems obtain this estimate by performing an interferometric measurement between a local frequency- modulated laser beam and a delayed copy returning from the target. The range estimate is formed by mixing the target-return field with the local reference field on a beamsplitter and detecting the resultant beat modulation. In conventional FMCW ranging, the source modulation is linear in instantaneous frequency, the reference-arm field has many more photons than the target-return field, and the time-of-flight estimate is generated by balanced difference- detection of the beamsplitter output, followed by a frequency-domain peak search. This work focused on determining the maximum-likelihood (ML) estimation algorithm when continuous-time photoncounting detectors are used. It is founded on a rigorous statistical characterization of the (random) photoelectron emission times as a function of the incident optical field, including the deleterious effects caused by dark current and dead time. These statistics enable derivation of the Cramér-Rao lower bound (CRB) on the accuracy of FMCW ranging, and derivation of the ML estimator, whose performance approaches this bound at high photon flux. The estimation algorithm was developed, and its optimality properties were shown in simulation. Experimental data show that it performs better than the conventional estimation algorithms used. The demonstrated improvement is a factor of 1.414 over frequency-domainbased estimation. If the target interrogating photons and the local reference field photons are costed equally, the optimal allocation of photons between these two arms is to have them equally distributed. This is different than the state of the art, in which the local field is stronger than the target return. The optimal

  18. Frequency-modulated laser ranging sensor with closed-loop control

    Science.gov (United States)

    Müller, Fabian M.; Böttger, Gunnar; Janeczka, Christian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Schneider-Ramelow, Martin

    2018-02-01

    Advances in autonomous driving and robotics are creating high demand for inexpensive and mass-producible distance sensors. A laser ranging system (Lidar), based on the frequency-modulated continuous-wave (FMCW) method is built in this work. The benefits of an FMCW Lidar system are the low-cost components and the performance in comparison to conventional time-of-flight Lidar systems. The basic system consists of a DFB laser diode (λ= 1308 nm) and an asymmetric fiber-coupled Mach-Zehnder interferometer with a fixed delay line in one arm. Linear tuning of the laser optical frequency via injection current modulation creates a beat signal at the interferometer output. The frequency of the beat signal is proportional to the optical path difference in the interferometer. Since the laser frequency-to-current response is non-linear, a closed-loop feed-back system is designed to improve the tuning linearity, and consequently the measurement resolution. For fast active control, an embedded system with FPGA is used, resulting in a nearly linear frequency tuning, realizing a narrow peak in the Fourier spectrum of the beat signal. For free-space measurements, a setup with two distinct interferometers is built. The fully fiber-coupled Mach-Zehnder reference interferometer is part of the feed-back loop system, while the other - a Michelson interferometer - has a free-space arm with collimator lens and reflective target. A resolution of 2:0 mm for a 560 mm distance is achieved. The results for varying target distances show high consistency and a linear relation to the measured beat-frequency.

  19. Experimental studies on the high-frequency heating of a plasma in the frequency range of the ion cyclotron harmonics

    International Nuclear Information System (INIS)

    Laeuter, R.

    1976-05-01

    Experiments on the HF heating of a plasma in a cylindrical arrangement with pump frequencies ω 0 in the ion cyclotron harmonics nωsub(ci) are described. A magnetized plasma of relativily high density (approximately 10 14 cm -3 ) is generated in a pinch-like source with pulsated gas inlet, and said plasma then expands along diverging magnetic-field lines in a quasi-static homogeneous guide field B 0 = 330 G. This results in a practically fully ionized, low-impurity and more or less homogeneous plasma column of a diameter of approximately 20 cm at a variable density between 5 x 10 11 and 5 x 10 12 cm -3 and at electron temperatures of 5 to 8 eV. A standing magneto-hydrodynamic wave is excited in this plasma by means of a 1.8 m Stix coil which is part of the anode resonant circuit of a pulsated 1 MHz 500-kW transmitter. The axial wavelength is lambdasub(z) = 45 cm, the pulse duration amounts to tau = 200 μs. The degree of modulation B tilde/B 0 of the quasi-static magnetic field by the HF field is adjustable and ranges between 0.015 and 0.06. The heating at 2ωsub(ci) and 4ωsub(ci) is investigated within this study. Efficiency measurements show that a very effective energy transfer to the plasma occurs with both frequencies. Ion temperatures between 70 and 100 eV are ascertained by means of a retarding-potential spectrometer. For plasma heating, similar turbulent mechanisms seem to be responsible in both cases whereas the linear wave-particle resonance at 2ωsub(ci) seems to be of subordinated importance. The theoretically assumed parametric decay into ion-Bernstein waves, which should be possible at 4 ωsub(ci), is not observed. Measurements with compensated magnetic loops and electrostatic probes make a disturbance of the radial plasma confinement obvious, by which an anormally high pulse frequency might be explained. (orig.) [de

  20. Frequency Diverse Array Radar Signal Processing via Space-Range-Doppler Focus (SRDF Method

    Directory of Open Access Journals (Sweden)

    Chen Xiaolong

    2018-04-01

    Full Text Available To meet the urgent demand of low-observable moving target detection in complex environments, a novel method of Frequency Diverse Array (FDA radar signal processing method based on Space-Rang-Doppler Focusing (SRDF is proposed in this paper. The current development status of the FDA radar, the design of the array structure, beamforming, and joint estimation of distance and angle are systematically reviewed. The extra degrees of freedom provided by FDA radar are fully utilizsed, which include the Degrees Of Freedom (DOFs of the transmitted waveform, the location of array elements, correlation of beam azimuth and distance, and the long dwell time, which are also the DOFs in joint spatial (angle, distance, and frequency (Doppler dimensions. Simulation results show that the proposed method has the potential of improving target detection and parameter estimation for weak moving targets in complex environments and has broad application prospects in clutter and interference suppression, moving target refinement, etc..

  1. Historical overview of Ramsey spectroscopy and its relevance on Time and Frequency Metrology

    International Nuclear Information System (INIS)

    Amaral, M M; Tarelho, L V G; De Souza, M A; Baratto, A C; Garcia, G A; Muller, S T; De Martin, J Jr; Rodriguez, A S; Bebeachibuli, A; Magalhães, D V

    2016-01-01

    A brief overview of the historical evolution of the method of successive oscillatory fields developed by Norman Ramsey, and some different implementations of the decurrent methodology are presented. We use time and frequency standards, from Cs atomic beams to optical standards, as examples. The scientific progress and the technological implementation achieved through a partnership between USP-SC and INMETRO are shown on the characterization of each time and frequency standard. (paper)

  2. Fast wave heating experiments in the ion cyclotron range of frequencies on ATF

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, M; Shepard, T D; Goulding, R H [Oak Ridge National Lab., TN (United States); and others

    1992-07-01

    Fast wave heating experiments in the ion cyclotron range of frequencies (ICRF) were performed on target plasmas produced by 350 kW of electron cyclotron heating at 53 GHz and also by neutral beam injection in the Advanced Toroidal Facility (ATF). Various heating regimes were investigated in the frequency range between 9.2 MHz and 28.8 MHz with magnetic fields of 0.95 T and 1.9 T on axis. The nominal pulse lengths of up to 200 kW RF power were in the range between 100 and 400 ms. Data from spectroscopy, loading measurements, and edge RF and Langmuir probes were used to characterize the RF induced effects on the ATF plasma. In the hydrogen minority regime at low plasma density, large suprathermal ion tails were observed with a neutral particle analyser. At high density (n-bar{sub e} {>=} 5.0 x 10{sup 13} cm{sup -3}) substantial increases in antenna loading were observed, but ICRF power was insufficient to produce definitive heating results. A two-dimensional RF heating code, ORION, and a Fokker-Planck code, RFTRANS, were used to simulate these experiments. A simulation of future high power, higher density experiments in ATF indicates improved bulk heating results due to the improved loading and more efficient thermalization of the minority tail. (author). 29 refs, 16 figs, 3 tabs.

  3. Radio frequency (RF) time-of-flight ranging for wireless sensor networks

    International Nuclear Information System (INIS)

    Thorbjornsen, B; White, N M; Brown, A D; Reeve, J S

    2010-01-01

    Position information of nodes within wireless sensor networks (WSNs) is often a requirement in order to make use of the data recorded by the sensors themselves. On deployment the nodes normally have no prior knowledge of their position and thus a locationing mechanism is required to determine their positions. In this paper, we describe a method to determine the point-to-point range between sensor nodes as part of the locationing process. A two-way time-of-flight (TOF) ranging scheme is presented using narrow-band RF. The frequency difference between the transceivers involved with the point-to-point measurement is used to obtain a sub-clock TOF phase offset measurement in order to achieve high resolution TOF measurements. The ranging algorithm has been developed and prototyped on a TI CC2430 development kit with no additional hardware being required. Performance results have been obtained for the line-of-sight (LOS), non-line-of-sight (NLOS) and indoor conditions. Accuracy is typically better than 7.0 m RMS for the LOS condition over 250.0 m and 15.8 m RMS for the NLOS condition over 120.0 m using a 100 sample average. Indoor accuracy is measured to 1.7 m RMS using a 1000 sample average over 8.0 m. Ranging error is linear and does not increase with the increased transmitter–receiver distance. Our TOA ranging scheme demonstrates a novel system where resolution and accuracy are time dependent in comparison with alternative frequency-dependent methods using narrow-band RF

  4. Diversification Rates and the Evolution of Species Range Size Frequency Distribution

    Directory of Open Access Journals (Sweden)

    Silvia Castiglione

    2017-11-01

    Full Text Available The geographic range sizes frequency distribution (RFD within clades is typically right-skewed with untransformed data, and bell-shaped or slightly left-skewed under the log-transformation. This means that most species within clades occupy diminutive ranges, whereas just a few species are truly widespread. A number of ecological and evolutionary explanations have been proposed to account for this pattern. Among the latter, much attention has been given to the issue of how extinction and speciation probabilities influence RFD. Numerous accounts now convincingly demonstrate that extinction rate decreases with range size, both in living and extinct taxa. The relationship between range size and speciation rate, though, is much less obvious, with either small or large ranged species being proposed to originate more daughter taxa. Herein, we used a large fossil database including 21 animal clades and more than 80,000 fossil occurrences distributed over more than 400 million years of marine metazoans (exclusive of vertebrates evolution, to test the relationship between extinction rate, speciation rate, and range size. As expected, we found that extinction rate almost linearly decreases with range size. In contrast, speciation rate peaks at the large (but not the largest end of the range size spectrum. This is consistent with the peripheral isolation mode of allopatric speciation being the main mechanism of species origination. The huge variation in phylogeny, fossilization potential, time of fossilization, and the overarching effect of mass extinctions suggest caution must be posed at generalizing our results, as individual clades may deviate significantly from the general pattern.

  5. Hyper capacity of MCM-41 supramoleculer structure in the radio- frequency range

    OpenAIRE

    I.I. Grygorchak; S.A. Vojtovych; Z.A. Stotsko; B.A. Seredyuk; N.K. Tovstyuk

    2011-01-01

    Purpose: of this paper was: 1) to synthesize supramolecular МСМ-41 structure (p-cyanogen phenyl ether of n-heptyl benzoic acid - 40%)>> with inserted guested nematic and 2) to study its dielectric properties.Design/methodology/approach: Supramolecular МСМ-41 structure has been synthesized by vacuum encapsulated method at room temperature. Dielectric properties have been studied by impedance spectroscopy method in the frequency range 10-3-106 Hz by “AUTOLAB” complex of “ECO CHEMIE” (Holland),...

  6. Nanostructured composite layers for electromagnetic shielding in the GHz frequency range

    Science.gov (United States)

    Suchea, M.; Tudose, I. V.; Tzagkarakis, G.; Kenanakis, G.; Katharakis, M.; Drakakis, E.; Koudoumas, E.

    2015-10-01

    We report on preliminary results regarding the applicability of nanostructured composite layers for electromagnetic shielding in the frequency range of 4-20 GHz. Various combinations of materials were employed including poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), polyaniline, graphene nanoplatelets, carbon nanotubes, Cu nanoparticles and Poly(vinyl alcohol). As shown, paint-like nanocomposite layers consisting of graphene nanoplatelets, polyaniline PEDOT:PSS and Poly(vinyl alcohol) can offer quite effective electromagnetic shielding, similar or even better than that of commercial products, the response strongly depending on their thickness and resistivity.

  7. Some recent multi-frequency electron paramagnetic resonance results on systems relevant for dosimetry and dating.

    Science.gov (United States)

    Callens, F; Vanhaelewyn, G; Matthys, P

    2002-04-01

    Electron Paramagnetic Resonance (EPR) applications like e.g. EPR dosimetry and dating, are usually performed at X-band frequencies because of practical reasons (cost, sample size, etc.). However, it is increasingly recognized that the radiation-induced EPR signals are strongly composite, what might affect dose/age estimates. A few recent examples from both the dosimetry and dating field, illustrating the problems, will be presented. The involved spectra are mainly due to carbonate-derived radicals (CO2-, CO3(3-), etc.). Measurements at higher microwave frequencies are often recommended to improve the insight into the spectra and/or the practical signal quantification. Recent results at Q- and W-band frequencies will show that a multi-frequency approach indeed opens many interesting perspectives in this field but also that each frequency may have specific (dis)advantages depending on the EPR probe and application involved. The discussion will concern carbonate-containing apatite single crystals, shells, modern and fossil tooth enamel.

  8. Modulation of auroral electron fluxes in the frequency range 50 kHz to 10 MHz

    Science.gov (United States)

    Spiger, R. J.; Murphree, J. S.; Anderson, H. R.; Loewenstein, R. F.

    1976-01-01

    A sounding rocket-borne electron detector of high time resolution is used to search for modulation of auroral electron fluxes in the frequency range 50 kHz to 10 MHz and energy range 5-7 keV. Data were telemetered to ground via a 93-kHz subcarrier. A cross-correlation analysis of the data collected indicates low-level modulation near the detection threshold of the instrument. Two U-1 events are observed which are interpreted as indications of modulation. The two modulation events occur during a period of increasing flux for a region marking the boundary between two current sheets detected by the payload magnetometer. The strongest argument against interference contamination is the lack of any observable modulation at times other than those mentioned in the study.

  9. Tunable femtosecond laser in the visible range with an intracavity frequency-doubled optical parametric oscillator

    International Nuclear Information System (INIS)

    Zhu Jiang-Feng; Xu Liang; Lin Qing-Feng; Zhong Xin; Han Hai-Nian; Wei Zhi-Yi

    2013-01-01

    We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical parametric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in combination with a lithium triborate (LBO) as the doubling crystal. A Kerr-lens-mode-locked (KLM) Ti:sapphire oscillator at the wavelength of 790 nm was used as the pump source, which was capable of generating pulses with a duration as short as 117 fs. A tunable femtosecond laser covering the 624–672 nm range was realized by conveniently adjusting the OPO cavity length. A maximum average output power of 260 mW in the visible range was obtained at the pump power of 2.2 W, with a typical pulse duration of 205 fs assuming a sech 2 pulse profile. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  10. Alteration of frequency range for binaural beats in acute low-tone hearing loss.

    Science.gov (United States)

    Karino, Shotaro; Yamasoba, Tatsuya; Ito, Ken; Kaga, Kimitaka

    2005-01-01

    The effect of acute low-tone sensorineural hearing loss (ALHL) on the interaural frequency difference (IFD) required for perception of binaural beats (BBs) was investigated in 12 patients with unilateral ALHL and 7 patients in whom ALHL had lessened. A continuous pure tone of 30 dB sensation level at 250 Hz was presented to the contralateral, normal-hearing ear. The presence of BBs was determined by a subjective yes-no procedure as the frequency of a loudness-balanced test tone was gradually adjusted around 250 Hz in the affected ear. The frequency range in which no BBs were perceived (FRNB) was significantly wider in the patients with ALHL than in the controls, and FRNBs became narrower in the recovered ALHL group. Specifically, detection of slow BBs with a small IFD was impaired in this limited (10 s) observation period. The significant correlation between the hearing level at 250 Hz and FRNBs suggests that FRNBs represent the degree of cochlear damage caused by ALHL.

  11. Nanostructured composite layers for electromagnetic shielding in the GHz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Suchea, M. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Chemistry and Physics, “Al.I. Cuza” University of Iasi, Iasi (Romania); Tudose, I.V. [Chemistry and Physics, “Al.I. Cuza” University of Iasi, Iasi (Romania); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Tzagkarakis, G. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kenanakis, G. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas, Heraklion (Greece); Katharakis, M. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Drakakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Koudoumas, E., E-mail: koudoumas@staff.teicrete.gr [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece)

    2015-10-15

    Graphical abstract: - Highlights: • Paint-like nanocomposite layers consisting of graphene nanoplatelets, PANI:HCl and PEDOT:PSS present very effective attenuation of electromagnetic radiation in the frequency range 4–20 GHz. • The shielding performance is based mostly on the graphene nanoplatelets and supported by PANI:HCl. In contrast, PEDOT:PSS plays mainly the role of the binder. • Increasing resistivity was observed to reduce the shielding effect, while increasing thickness to favor it. - Abstract: We report on preliminary results regarding the applicability of nanostructured composite layers for electromagnetic shielding in the frequency range of 4–20 GHz. Various combinations of materials were employed including poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), polyaniline, graphene nanoplatelets, carbon nanotubes, Cu nanoparticles and Poly(vinyl alcohol). As shown, paint-like nanocomposite layers consisting of graphene nanoplatelets, polyaniline PEDOT:PSS and Poly(vinyl alcohol) can offer quite effective electromagnetic shielding, similar or even better than that of commercial products, the response strongly depending on their thickness and resistivity.

  12. Multi-year high-frequency hydrothermal monitoring of selected high-threat Cascade Range volcanoes

    Science.gov (United States)

    Crankshaw, I. M.; Archfield, S. A.; Newman, A. C.; Bergfeld, D.; Clor, L. E.; Spicer, K. R.; Kelly, P. J.; Evans, W. C.; Ingebritsen, S. E.

    2018-05-01

    From 2009 to 2015 the U.S. Geological Survey (USGS) systematically monitored hydrothermal behavior at selected Cascade Range volcanoes in order to define baseline hydrothermal and geochemical conditions. Gas and water data were collected regularly at 25 sites on 10 of the highest-risk volcanoes in the Cascade Range. These sites include near-summit fumarole groups and springs/streams that show clear evidence of magmatic influence (high 3He/4He ratios and/or large fluxes of magmatic CO2 or heat). Site records consist mainly of hourly temperature and hydrothermal-flux data. Having established baseline conditions during a multiyear quiescent period, the USGS reduced monitoring frequency from 2015 to present. The archived monitoring data are housed at (doi:10.5066/F72N5088). These data (1) are suitable for retrospective comparison with other continuous geophysical monitoring data and (2) will provide context during future episodes of volcanic unrest, such that unrest-related variations at these thoroughly characterized sites will be more clearly recognizable. Relatively high-frequency year-round data are essential to achieve these objectives, because many of the time series reveal significant diurnal, seasonal, and inter-annual variability that would tend to mask unrest signals in the absence of baseline data. Here we characterize normal variability for each site, suggest strategies to detect future volcanic unrest, and explore deviations from background associated with recent unrest.

  13. Nanostructured composite layers for electromagnetic shielding in the GHz frequency range

    International Nuclear Information System (INIS)

    Suchea, M.; Tudose, I.V.; Tzagkarakis, G.; Kenanakis, G.; Katharakis, M.; Drakakis, E.; Koudoumas, E.

    2015-01-01

    Graphical abstract: - Highlights: • Paint-like nanocomposite layers consisting of graphene nanoplatelets, PANI:HCl and PEDOT:PSS present very effective attenuation of electromagnetic radiation in the frequency range 4–20 GHz. • The shielding performance is based mostly on the graphene nanoplatelets and supported by PANI:HCl. In contrast, PEDOT:PSS plays mainly the role of the binder. • Increasing resistivity was observed to reduce the shielding effect, while increasing thickness to favor it. - Abstract: We report on preliminary results regarding the applicability of nanostructured composite layers for electromagnetic shielding in the frequency range of 4–20 GHz. Various combinations of materials were employed including poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), polyaniline, graphene nanoplatelets, carbon nanotubes, Cu nanoparticles and Poly(vinyl alcohol). As shown, paint-like nanocomposite layers consisting of graphene nanoplatelets, polyaniline PEDOT:PSS and Poly(vinyl alcohol) can offer quite effective electromagnetic shielding, similar or even better than that of commercial products, the response strongly depending on their thickness and resistivity.

  14. Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

    Science.gov (United States)

    Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

    2007-01-01

    The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

  15. Reflecting and Polarizing Properties of Conductive Fabrics in Ultra-High Frequency Range

    Directory of Open Access Journals (Sweden)

    Oleg Kiprijanovič

    2015-09-01

    Full Text Available The system based on ultra-wide band (UWB signals was employed for qualitative estimation of attenuating, reflecting and polarizing properties of conductive fabrics, capable to prevent local static charge accumulation. Pulsed excitation of triangle monopole antenna of 6.5 cm height by rectangular electric pulses induced radiation of UWB signals with spectral density of power having maximum in ultra-high frequency (UHF range. The same antenna was used for the radiated signal receiving. Filters and amplifiers of different passband were employed to divide UHF range into subranges of 0.3-0.55 GHz, 0.55-1 GHz, 1-2 GHz and 2-4 GHz bands. The free space method, when conductive fabric samples of 50x50 cm2 were placed between transmitting and receiving antennas, was used to imitate a practical application. Received wideband signals corresponding to the defined range were detected by unbiased detectors. The fabrics made of two types of warps, containing different threads with conductive yarns, were investigated. It was estimated attenuation and reflective properties of the fabrics when electric field is collinear or perpendicular to thread direction. In the UHF range it was revealed good reflecting properties of the fabrics containing metallic component in the threads. The system has advantages but not without a certain shortcoming. Adapting it for specific tasks should lead to more effective usage, including yet unused properties of the UWB signals.

  16. Coupled quantum-classical method for long range charge transfer: relevance of the nuclear motion to the quantum electron dynamics

    International Nuclear Information System (INIS)

    Da Silva, Robson; Hoff, Diego A; Rego, Luis G C

    2015-01-01

    Charge and excitonic-energy transfer phenomena are fundamental for energy conversion in solar cells as well as artificial photosynthesis. Currently, much interest is being paid to light-harvesting and energy transduction processes in supramolecular structures, where nuclear dynamics has a major influence on electronic quantum dynamics. For this reason, the simulation of long range electron transfer in supramolecular structures, under environmental conditions described within an atomistic framework, has been a difficult problem to study. This work describes a coupled quantum mechanics/molecular mechanics method that aims at describing long range charge transfer processes in supramolecular systems, taking into account the atomistic details of large molecular structures, the underlying nuclear motion, and environmental effects. The method is applied to investigate the relevance of electron–nuclei interaction on the mechanisms for photo-induced electron–hole pair separation in dye-sensitized interfaces as well as electronic dynamics in molecular structures. (paper)

  17. Coherent lidar modulated with frequency stepped pulse trains for unambiguous high duty cycle range and velocity sensing in the atmosphere

    DEFF Research Database (Denmark)

    Lindelöw, Per Jonas Petter; Mohr, Johan Jacob

    2007-01-01

    Range unambiguous high duty cycle coherent lidars can be constructed based on frequency stepped pulse train modulation, even continuously emitting systems could be envisioned. Such systems are suitable for velocity sensing of dispersed targets, like the atmosphere, at fast acquisition rates....... The lightwave synthesized frequency sweeper is a suitable generator yielding fast pulse repetition rates and stable equidistant frequency steps. Theoretical range resolution profiles of modulated lidars are presented....

  18. Frequency and Prognostic Relevance of FLT3 Mutations in Saudi Acute Myeloid Leukemia Patients

    Directory of Open Access Journals (Sweden)

    Ghaleb Elyamany

    2014-01-01

    Full Text Available The Fms-like tyrosine kinase-3 (FLT3 is a receptor tyrosine kinase that plays a key role in cell survival, proliferation, and differentiation of hematopoietic stem cells. Mutations of FLT3 were first described in 1997 and account for the most frequent molecular mutations in acute myeloid leukemia (AML. AML patients with FLT3 internal tandem duplication (ITD mutations have poor cure rates the prognostic significance of point mutations; tyrosine kinase domain (TKD is still unclear. We analyzed the frequency of FLT3 mutations (ITD and D835 in patients with AML at diagnosis; no sufficient data currently exist regarding FLT3 mutations in Saudi AML patients. This study was aimed at evaluating the frequency of FLT3 mutations in patients with AML and its significance for prognosis. The frequency of FLT3 mutations in our study (18.56% was lower than many of the reported studies, FLT3-ITD mutations were observed in 14.4%, and FLT3-TKD in 4.1%, of 97 newly diagnosed AML patients (82 adult and 15 pediatric. Our data show significant increase of FLT3 mutations in male more than female (13 male, 5 female. Our results support the view that FLT3-ITD mutation has strong prognostic factor in AML patients and is associated with high rate of relapse, and high leucocytes and blast count at diagnosis and relapse.

  19. Historic Frequency and Severity of Fire in Whitebark Pine Forests of the Cascade Mountain Range, USA

    Directory of Open Access Journals (Sweden)

    Michael P. Murray

    2018-02-01

    Full Text Available Whitebark pine (Pinus albicaulis Engelm. is a foundation species of high elevation forest ecosystems in the Cascade Mountain Range of Oregon, Washington, and British Columbia. We examined fire evidence on 55 fire history sites located in the Cascade Range. To estimate dates of historic fires we analyzed 57 partial cross-sections from fire-scarred trees plus 700 increment cores. The resulting 101 fire events indicate fire has been a widespread component of Cascadian whitebark pine stands. Results are site specific and vary considerably. Whitebark pine stands appear to burn in a variety of severities and frequencies. Sites where fire intervals were detected ranged from 9 to 314 years, with a median of 49 years, and averaging 67 years. Fire intervals shortened significantly with higher latitudes. In assessing the most recent fire event at each site, overall, 56 percent burned as stand replacing events. In the 20th century, the number of fires diminished significantly. Due to conservation imperatives, re-introducing fire should be undertaken with extreme care to avoid substantial mortality of this endangered species.

  20. A New Microwave Shield Preparation for Super High Frequency Range: Occupational Approach to Radiation Protection.

    Science.gov (United States)

    Zaroushani, Vida; Khavanin, Ali; Jonidi Jafari, Ahmad; Mortazavi, Seyed Bagher

    2016-01-01

    Widespread use of X-band frequency (a part of the super high frequency microwave) in the various workplaces would contribute to occupational exposure with potential of adverse health effects.  According to limited study on microwave shielding for the workplace, this study tried to prepare a new microwave shielding for this purpose. We used EI-403 epoxy thermosetting resin as a matrix and nickel oxide nanoparticle with the diameter of 15-35 nm as filler. The Epoxy/ Nickel oxide composites with 5, 7, 9 and 11 wt% were made in three different thicknesses (2, 4 and 6 mm). According to transmission / reflection method, shielding effectiveness (SE) in the X-band frequency range (8-12.5 GHz) was measured by scattering parameters directly given by the 2-port Vector Network Analyzer. The fabricated composites characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope. The best average of shielding effectiveness in each thickness of fabricated composites obtained by 11%-2 mm, 7%-4 mm and 7%-6 mm composites with SE values of 46.80%, 66.72% and 64.52%, respectively. In addition, the 11%-6 mm, 5%-6 mm and 11%-4 mm-fabricated composites were able to attenuate extremely the incident microwave energy at 8.01, 8.51 and 8.53 GHz by SE of 84.14%, 83.57 and 81.30%, respectively. The 7%-4mm composite could be introduced as a suitable alternative microwave shield in radiation protection topics in order to its proper SE and other preferable properties such as low cost and weight, resistance to corrosion etc. It is necessary to develop and investigate the efficacy of the fabricated composites in the fields by future studies.

  1. Dynamics of r.f. production of Stellarator plasmas in the ion cyclotron range of frequency

    International Nuclear Information System (INIS)

    Moiseenko, V.E.; Lysoivan, A.I.; Kasilov, S.V.; Plyusnin, V.V.

    1995-01-01

    The present study investigated numerically the process of r.f. production of plasma in the URAGAN-3M torsatron in the frequency range below the ion cyclotron frequency (ω ci ). The dynamics of r.f. plasma build-up at the stages of neutral gas burnout and plasma heating were studied using a zero-dimensional transport code, in which the plasma confinement law was determined by large helical device scaling. Two models for input r.f. power were used. In the first case, the r.f. power absorbed by the electrons was computed by a one-dimensional r.f. code solving Maxwell's boundary problem equations. The mechanisms of electron heating through direct excitation of the slow wave (SW) by antennae as well as the conversion of fast wave (FW) into SW in the vicinity of Alfven resonance (scenario of Alfven heating) were taken into account in the computations. In the second case, an 'ideal' model of r.f. power deposition onto the electrons as a linear function of plasma density was employed. A noticeable difference in plasma production dynamics computed for these two cases was found. Better agreement with experimental data obtained from the URAGAN-3M torsatron was found for the first case resulting from combination of the one-dimensional r.f. and zero-dimensional transport codes. ((orig.))

  2. Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer.

    Directory of Open Access Journals (Sweden)

    SangWook Park

    Full Text Available In this paper, a numerical exposure assessment method is presented for a quasi-static analysis by the use of finite-difference time-domain (FDTD algorithm. The proposed method is composed of scattered field FDTD method and quasi-static approximation for analyzing of the low frequency band electromagnetic problems. The proposed method provides an effective tool to compute induced electric fields in an anatomically realistic human voxel model exposed to an arbitrary non-uniform field source in the low frequency ranges. The method is verified, and excellent agreement with theoretical solutions is found for a dielectric sphere model exposed to a magnetic dipole source. The assessment method serves a practical example of the electric fields, current densities, and specific absorption rates induced in a human head and body in close proximity to a 150-kHz wireless power transfer system for cell phone charging. The results are compared to the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP and the IEEE standard guidelines.

  3. Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer

    Science.gov (United States)

    Kim, Minhyuk

    2016-01-01

    In this paper, a numerical exposure assessment method is presented for a quasi-static analysis by the use of finite-difference time-domain (FDTD) algorithm. The proposed method is composed of scattered field FDTD method and quasi-static approximation for analyzing of the low frequency band electromagnetic problems. The proposed method provides an effective tool to compute induced electric fields in an anatomically realistic human voxel model exposed to an arbitrary non-uniform field source in the low frequency ranges. The method is verified, and excellent agreement with theoretical solutions is found for a dielectric sphere model exposed to a magnetic dipole source. The assessment method serves a practical example of the electric fields, current densities, and specific absorption rates induced in a human head and body in close proximity to a 150-kHz wireless power transfer system for cell phone charging. The results are compared to the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the IEEE standard guidelines. PMID:27898688

  4. Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer.

    Science.gov (United States)

    Park, SangWook; Kim, Minhyuk

    2016-01-01

    In this paper, a numerical exposure assessment method is presented for a quasi-static analysis by the use of finite-difference time-domain (FDTD) algorithm. The proposed method is composed of scattered field FDTD method and quasi-static approximation for analyzing of the low frequency band electromagnetic problems. The proposed method provides an effective tool to compute induced electric fields in an anatomically realistic human voxel model exposed to an arbitrary non-uniform field source in the low frequency ranges. The method is verified, and excellent agreement with theoretical solutions is found for a dielectric sphere model exposed to a magnetic dipole source. The assessment method serves a practical example of the electric fields, current densities, and specific absorption rates induced in a human head and body in close proximity to a 150-kHz wireless power transfer system for cell phone charging. The results are compared to the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the IEEE standard guidelines.

  5. Simple Wide Frequency Range Impedance Meter Based on AD5933 Integrated Circuit

    Directory of Open Access Journals (Sweden)

    Chabowski Konrad

    2015-03-01

    Full Text Available As it contains elements of complete digital impedance meter, the AD5933 integrated circuit is an interesting solution for impedance measurements. However, its use for measurements in a wide range of impedances and frequencies requires an additional digital and analogue circuitry. This paper presents the design and performance of a simple impedance meter based on the AD5933 IC. Apart from the AD5933 IC it consists of a clock generator with a programmable prescaler, a novel DC offset canceller for the excitation signal based on peak detectors and a current to voltage converter with switchable conversion ratios. The authors proposed a simple method for choosing the measurement frequency to minimalize errors resulting from the spectral leakage and distortion caused by a lack of an anti-aliasing filter in the DDS generator. Additionally, a novel method for the AD5933 IC calibration was proposed. It consists in a mathematical compensation of the systematic error occurring in the argument of the value returned from the AD5933 IC as a result. The performance of the whole system is demonstrated in an exemplary measurement.

  6. Paternal kin recognition in the high frequency / ultrasonic range in a solitary foraging mammal

    Directory of Open Access Journals (Sweden)

    Kessler Sharon E

    2012-11-01

    Full Text Available Abstract Background Kin selection is a driving force in the evolution of mammalian social complexity. Recognition of paternal kin using vocalizations occurs in taxa with cohesive, complex social groups. This is the first investigation of paternal kin recognition via vocalizations in a small-brained, solitary foraging mammal, the grey mouse lemur (Microcebus murinus, a frequent model for ancestral primates. We analyzed the high frequency/ultrasonic male advertisement (courtship call and alarm call. Results Multi-parametric analyses of the calls’ acoustic parameters and discriminant function analyses showed that advertisement calls, but not alarm calls, contain patrilineal signatures. Playback experiments controlling for familiarity showed that females paid more attention to advertisement calls from unrelated males than from their fathers. Reactions to alarm calls from unrelated males and fathers did not differ. Conclusions 1 Findings provide the first evidence of paternal kin recognition via vocalizations in a small-brained, solitarily foraging mammal. 2 High predation, small body size, and dispersed social systems may select for acoustic paternal kin recognition in the high frequency/ultrasonic ranges, thus limiting risks of inbreeding and eavesdropping by predators or conspecific competitors. 3 Paternal kin recognition via vocalizations in mammals is not dependent upon a large brain and high social complexity, but may already have been an integral part of the dispersed social networks from which more complex, kin-based sociality emerged.

  7. Measurements on rotating ion cyclotron range of frequencies induced particle fluxes in axisymmetric mirror plasmas

    International Nuclear Information System (INIS)

    Hatakeyama, R.; Hershkowitz, N.; Majeski, R.; Wen, Y.J.; Brouchous, D.B.; Proberts, P.; Breun, R.A.; Roberts, D.; Vukovic, M.; Tanaka, T.

    1997-01-01

    A comparison of phenomenological features of plasmas is made with a special emphasis on radio-frequency induced transport, which are maintained when a set of two closely spaced dual half-turn antennas in a central cell of the Phaedrus-B axisymmetric tandem mirror [J. J. Browning et al., Phys. Fluids B 1, 1692 (1989)] is phased to excite electromagnetic fields in the ion cyclotron range of frequencies (ICRF) with m=-1 (rotating with ions) and m=+1 (rotating with electrons) azimuthal modes. Positive and negative electric currents are measured to flow axially to the end walls in the cases of m=-1 and m=+1 excitations, respectively. These parallel nonambipolar ion and electron fluxes are observed to be accompanied by azimuthal ion flows in the same directions as the antenna-excitation modes m. The phenomena are argued in terms of radial particle fluxes due to a nonambipolar transport mechanism [Hojo and Hatori, J. Phys. Soc. Jpn. 60, 2510 (1991); Hatakeyama et al., J. Phys. Soc. Jpn. 60, 2815 (1991), and Phys. Rev. E 52, 6664 (1995)], which are induced when azimuthally traveling ICRF waves are absorbed in the magnetized plasma column. copyright 1997 American Institute of Physics

  8. Fiber optic probe of free electron evanescent fields in the optical frequency range

    Energy Technology Data Exchange (ETDEWEB)

    So, Jin-Kyu, E-mail: js1m10@orc.soton.ac.uk; MacDonald, Kevin F. [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Zheludev, Nikolay I. [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371 (Singapore)

    2014-05-19

    We introduce an optical fiber platform which can be used to interrogate proximity interactions between free-electron evanescent fields and photonic nanostructures at optical frequencies in a manner similar to that in which optical evanescent fields are sampled using nanoscale aperture probes in scanning near-field microscopy. Conically profiled optical fiber tips functionalized with nano-gratings are employed to couple electron evanescent fields to light via the Smith-Purcell effect. We demonstrate the interrogation of medium energy (30–50 keV) electron fields with a lateral resolution of a few micrometers via the generation and detection of visible/UV radiation in the 700–300 nm (free-space) wavelength range.

  9. Verification of the effects of Schumann frequency range electromagnetic fields on the human cardiovascular system

    Science.gov (United States)

    Tuzhilkin, D. A.; Borodin, A. S.

    2017-11-01

    The results of the study of variations in the electromagnetic background parameters of the Schumann resonator frequency range and the variability indices of the human heart period during its free activity are presented on the basis of 24-hour synchronous monitoring data. It is shown that the integral evaluation of the conjugacy of the heart rate variability indices from the Schumann resonance parameters is extremely weak. In this case, the differential evaluation of this dependence with separation into characteristic time intervals of the day, characterized by different motor activity of the subjects, becomes significantly higher. The number of volunteers whose conjugacy is characterized by a strong correlation in some cases reaches 35 percent of the sample.

  10. Absolute distance measurement with extension of nonambiguity range using the frequency comb of a femtosecond laser

    Science.gov (United States)

    Jang, Yoon-Soo; Lee, Keunwoo; Han, Seongheum; Lee, Joohyung; Kim, Young-Jin; Kim, Seung-Woo

    2014-12-01

    We revisit the method of synthetic wavelength interferometry (SWI) for absolute measurement of long distances using the radio-frequency harmonics of the pulse repetition rate of a mode-locked femtosecond laser. Our intention here is to extend the nonambiguity range (NAR) of the SWI method using a coarse virtual wavelength synthesized by shifting the pulse repetition rate. The proposed concept of NAR extension is experimentally verified by measuring a ˜13-m distance with repeatability of 9.5 μm (root-mean-square). The measurement precision is estimated to be 31.2 μm in comparison with an incremental He-Ne laser interferometer. This extended SWI method is found to be well suited for long-distance measurements demanded in the fields of large-scale precision engineering, geodetic survey, and future space missions.

  11. Trend extraction of rail corrugation measured dynamically based on the relevant low-frequency principal components reconstruction

    International Nuclear Information System (INIS)

    Li, Yanfu; Liu, Hongli; Ma, Ziji

    2016-01-01

    Rail corrugation dynamic measurement techniques are critical to guarantee transport security and guide rail maintenance. During the inspection process, low-frequency trends caused by rail fluctuation are usually superimposed on rail corrugation and seriously affect the assessment of rail maintenance quality. In order to extract and remove the nonlinear and non-stationary trends from original mixed signals, a hybrid model based ensemble empirical mode decomposition (EEMD) and modified principal component analysis (MPCA) is proposed in this paper. Compared with the existing de-trending methods based on EMD, this method first considers low-frequency intrinsic mode functions (IMFs) thought to be underlying trend components that maybe contain some unrelated components, such as white noise and low-frequency signal itself, and proposes to use PCA to accurately extract the pure trends from the IMFs containing multiple components. On the other hand, due to the energy contribution ratio between trends and mixed signals is prior unknown, and the principal components (PCs) decomposed by PCA are arranged in order of energy reduction without considering frequency distribution, the proposed method modifies traditional PCA and just selects relevant low-frequency PCs to reconstruct the trends based on the zero-crossing numbers (ZCN) of each PC. Extensive tests are presented to illustrate the effectiveness of the proposed method. The results show the proposed EEMD-PCA-ZCN is an effective tool for trend extraction of rail corrugation measured dynamically. (paper)

  12. Development of a Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

    Science.gov (United States)

    Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

    2007-01-01

    The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and. control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for inter-spacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of medium, moving platforms, and radiated power. The Path Emulator for RF Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

  13. Opto-electronic device for frequency standard generation and terahertz-range optical demodulation based on quantum interference

    Science.gov (United States)

    Georgiades, Nikos P.; Polzik, Eugene S.; Kimble, H. Jeff

    1999-02-02

    An opto-electronic system and technique for comparing laser frequencies with large frequency separations, establishing new frequency standards, and achieving phase-sensitive detection at ultra high frequencies. Light responsive materials with multiple energy levels suitable for multi-photon excitation are preferably used for nonlinear mixing via quantum interference of different excitation paths affecting a common energy level. Demodulation of a carrier with a demodulation frequency up to 100's THZ can be achieved for frequency comparison and phase-sensitive detection. A large number of materials can be used to cover a wide spectral range including the ultra violet, visible and near infrared regions. In particular, absolute frequency measurement in a spectrum from 1.25 .mu.m to 1.66 .mu.m for fiber optics can be accomplished with a nearly continuous frequency coverage.

  14. An improved broadband method to evaluate effective parameters of slab metamaterials in the microwave frequency range

    International Nuclear Information System (INIS)

    Rybin, O.; Nawaz, T.; Abbasi, T.

    2007-01-01

    An improved broadband method for determining complex effective refractive index, permittivity and permeability of an arbitrary passive metamaterial in microwave frequency range has been proposed. Evaluation of the effective parameters is realized using the reflection-transmission S-parameters obtained by simulation or experimental measurements and analytically evaluated interface reflection coefficient of the slab. Formulas for evaluation of effective permittivity and permeability which contain the square root of complex functions of S-parameters have been proposed in (1-2). But this method does not propose a way to avoid an ambiguity arising in choosing the square root branch of product of effective permittivity and permeability. Moreover the above calculation procedure requires evaluating the square root branch of function of S-parameters. Proposed way to choose the square root branch gives sometimes mistaken results. Our method is much simple as compared with the above mentioned formulas and it does not require making a choice of square root branch of complex functions of S-parameters in order to evaluate any of the parameters (refractive index, permittivity or permeability). Instead we obtain a formula for complex refractive index which is simple. On the basis of proposed model effective permittivity and permeability for rod meta-materials can be evaluated with enhanced precision and accuracy. Proposed method is easy to be implemented in engineering problems and does not require using complicated mathematical calculations. Comparison of precision of the presented method with the Nicolson-Ross techniques (1-2) has been made using the simulations for different configurations of rod meta-materials. Some discussion concerning the sensitivity of the effective parameters of meta-materials for the accuracy of the frequency dependent S -parameters is also presented in this paper. (author)

  15. Effective conductivity and permittivity of unsaturated porous materials in the frequency range 1 mHz–1GHz

    Science.gov (United States)

    Revil, A

    2013-01-01

    A model combining low-frequency complex conductivity and high-frequency permittivity is developed in the frequency range from 1 mHz to 1 GHz. The low-frequency conductivity depends on pore water and surface conductivities. Surface conductivity is controlled by the electrical diffuse layer, the outer component of the electrical double layer coating the surface of the minerals. The frequency dependence of the effective quadrature conductivity shows three domains. Below a critical frequency fp, which depends on the dynamic pore throat size Λ, the quadrature conductivity is frequency dependent. Between fp and a second critical frequency fd, the quadrature conductivity is generally well described by a plateau when clay minerals are present in the material. Clay-free porous materials with a narrow grain size distribution are described by a Cole-Cole model. The characteristic frequency fd controls the transition between double layer polarization and the effect of the high-frequency permittivity of the material. The Maxwell-Wagner polarization is found to be relatively negligible. For a broad range of frequencies below 1 MHz, the effective permittivity exhibits a strong dependence with the cation exchange capacity and the specific surface area. At high frequency, above the critical frequency fd, the effective permittivity reaches a high-frequency asymptotic limit that is controlled by the two Archie's exponents m and n like the low-frequency electrical conductivity. The unified model is compared with various data sets from the literature and is able to explain fairly well a broad number of observations with a very small number of textural and electrochemical parameters. It could be therefore used to interpret induced polarization, induction-based electromagnetic methods, and ground penetrating radar data to characterize the vadose zone. PMID:23576823

  16. Investigation of factors influencing the efficacy of electromagnetic shielding in X band frequency range

    Directory of Open Access Journals (Sweden)

    Vida Zaroushani

    2016-12-01

    Full Text Available Introduction: Due to the importance of engineering controls for prevention of microwave exposure, this study was conducted to design and constract a novel electromagnetic shielding and also to examine the factors influencing shielding efficacy in X band frequency range. Material and Method: This study used Resin Epoxy as matrix and nano-Nickel Oxide as filler to prepare the composite plates with three different thicknesses (2,4, and 6 mm and four different weight percentages (5,7,9 and 11. The fabricated composites characterized using X-ray diffraction and Field Emission Scanning Electron microscopy. Shielding effectiveness, percolation depth, and percolation threshold were measured using Vector Network Analyzers. Thermal Gravimetric Analysis was conducted to study the temperature influence on weight loss for fabricated composites. Result: A maximum shielding effectiveness value of 84.18% was obtained for the 11%-6mm composite at 8.01 GHz and the 7%-4mm composite exhibits a higher average of shielding effectiveness of 66.72% at X- band frequency range. The 4mm thickness was optimum and critical diameter for composite plates; and percolation depth was obtained greater than thickness of composites. However, increasing the nickel oxide content did not show noticeable effect on the shielding effectiveness. Thermal Gravimetric Analysis showed that the study shields were resistant to temperature up to 150 °C without experiencing weight loss. What is more, the results indicated that Nickel oxide Nano particles had desirable distribution and dispersion in epoxy matrix and percolation threshold was appeared in low content of nickel oxide nanoparticles. Conclusion: A novel electromagnetic shield using low thickness and few content of nanoparticle with noticeable efficacy was properly designed and constructed in the field of occupational health. In addition, this shield has low cost, easy to manufacture, resistance to wet/corrosion, and low weight. Epoxy

  17. Experimental investigation of ion cyclotron range of frequencies heating scenarios for ITER's half-field hydrogen phase performed in JET

    NARCIS (Netherlands)

    Lerche, E.; Van Eester, D.; Johnson, T. J.; Hellsten, T.; Ongena, J.; Mayoral, M. L.; Frigione, D.; Sozzi, C.; Calabro, G.; Lennholm, M.; Beaumont, P.; Blackman, T.; Brennan, D.; Brett, A.; Cecconello, M.; Coffey, I.; Coyne, A.; Crombe, K.; Czarnecka, A.; Felton, R.; Giroud, C.; Gorini, G.; Hellesen, C.; Jacquet, P.; Kiptily, V.; Knipe, S.; Krasilnikov, A.; Maslov, M.; Monakhov, I.; Noble, C.; Nocente, M.; Pangioni, L.; Proverbio, I.; Sergienko, G.; Stamp, M.; Studholme, W.; Tardocchi, M.; Vdovin, V.; Versloot, T.; Voitsekhovitch, I.; Whitehurst, A.; Wooldridge, E.; Zoita, V.; JET-EFDA Contributors,

    2012-01-01

    Two ion cyclotron range of frequencies (ICRF) heating schemes proposed for the half-field operation phase of ITER in hydrogen plasmas—fundamental H majority and second harmonic 3 He ICRF heating—were recently investigated in JET. Although the same magnetic field and RF frequencies ( f ≈ 42 MHz and f

  18. Frequency Comb Driven Raman Transitions in the THz Range: High Precision Isotope Shift Measurements in Ca+

    DEFF Research Database (Denmark)

    Meyer, Steffen

    2017-01-01

    and frequency resolved optical gating (FROG) are used, and the two frequency comb systems used for the experiments are thoroughly characterized, a Coherent Mira Ti:sapph oscillator and a MenloSystems fiber based frequency comb system. The potential of frequency comb driven Raman transitions is shown...... transition frequencies typically are on the order of a few THz. High precision measurements on these ions have many intriguing applications, for example the test of time-variations of fundamental constants, ultracold chemistry on the quantum level, and quantum information and computing, to name just a few...

  19. Enhanced Field Emission Studies on Niobium Surfaces Relevant to High Field Superconducting Radio-Frequency Devices

    International Nuclear Information System (INIS)

    Tong Wang

    2002-01-01

    Enhanced field emission (EFE) presents the main impediment to higher acceleration gradients in superconducting niobium (Nb) radio frequency cavities for particle accelerators. The strength, number and sources of EFE sites strongly depend on surface preparation and handling. The main objective of this thesis project is to systematically investigate the sources of EFE from Nb, to evaluate the best available surface preparation techniques with respect to resulting field emission, and to establish an optimized process to minimize or eliminate EFE. To achieve these goals, a scanning field emission microscope (SFEM) was designed and built as an extension to an existing commercial scanning electron microscope (SEM). In the SFEM chamber of ultra high vacuum, a sample is moved laterally in a raster pattern under a high voltage anode tip for EFE detection and localization. The sample is then transferred under vacuum to the SEM chamber equipped with an energy-dispersive x-ray spectrometer for individual emitting site characterization. Compared to other systems built for similar purposes, this apparatus has low cost and maintenance, high operational flexibility, considerably bigger scan area, as well as reliable performance. EFE sources from planar Nb have been studied after various surface preparation, including chemical etching and electropolishing, combined with ultrasonic or high-pressure water rinse. Emitters have been identified, analyzed and the preparation process has been examined and improved based on EFE results. As a result, field-emission-free or near field-emission-free surfaces at ∼140 MV/m have been consistently achieved with the above techniques. Characterization on the remaining emitters leads to the conclusion that no evidence of intrinsic emitters, i.e., no fundamental electric field limit induced by EFE, has been observed up to ∼140 MV/m. Chemically etched and electropolished Nb are compared and no significant difference is observed up to ∼140 MV

  20. On the generation of electromagnetic waves in the terahertz frequency range

    International Nuclear Information System (INIS)

    Namiot, V.A.; Shchurova, L.Yu.

    2011-01-01

    It is shown that a thin dielectric plate, which can act as an open dielectric waveguide, it is possible to produce amplification and generation of electromagnetic waves with frequencies in the terahertz range. For this purpose, we propose using a dielectric plate with a corrugated surface, in which case the electric field of the transverse electromagnetic wave in the waveguide has a periodic spatial structure in the local area near to the corrugation. Terahertz electromagnetic waves are excited by a beam of electrons moving in vacuum along the dielectric plate at a small distance from its corrugated surface. Corrugation period is chosen in order to ensure the most effective interaction of the electron beam with the first harmonic of the electric field induced by the corrugation. Amplification and generation of electromagnetic waves propagating in a dielectric waveguide is realized as a result of deceleration of the electron beam by a wave electric field induced by a corrugated dielectric surface in the zone near the corrugation. We discuss possible ways to create electron beams with the desired characteristics. We offer a way to stabilize the beam position above the plate, avoiding the bombardment of the plate by electrons. It is shown that it is possible to significantly increase the efficiency of the device through the recovery of energy that remains in the electrons after their interaction with the wave. -- Highlights: → We propose a scheme of a generator of radio waves in the terahertz range. → This scheme includes a corrugated dielectric plate, which can act as an open waveguide. → A strip electron beam is in vacuum near the dielectric corrugated surface. → Generation is achieved by converting electrons' energy into electromagnetic energy. → The waveguide wave extends perpendicularly to electron motion.

  1. Ion beam generated modes in the lower hybrid frequency range in a laboratory magnetoplasma

    Science.gov (United States)

    Van Compernolle, B.; Tripathi, S.; Gekelman, W. N.; Colestock, P. L.; Pribyl, P.

    2012-12-01

    The generation of waves by ion ring distributions is of great importance in many instances in space plasmas. They occur naturally in the magnetosphere through the interaction with substorms, or they can be man-made in ionospheric experiments by photo-ionization of neutral atoms injected perpendicular to the earth's magnetic field. The interaction of a fast ion beam with a low β plasma has been studied in the laboratory. Experiments were performed at the LArge Plasma Device (LAPD) at UCLA. The experiments were done in a Helium plasma (n ≃ 1012 \\ cm-3, B0 = 1000 G - 1800 G, fpe}/f{ce ≃ 1 - 5, Te = 0.25\\ eV, vte ≤ vA). The ion beam \\cite{Tripathi_ionbeam} is a Helium beam with energies ranging from 5 keV to 18 keV. The fast ion velocity is on the order of the Alfvén velocity. The beam is injected from the end of the machine, and spirals down the linear device. Waves were observed below fci in the shear Alfvén wave regime, and in a broad spectrum above fci in the lower hybrid frequency range, the focus of this paper. The wave spectra have distinct peaks close to ion cyclotron harmonics, extending out to the 100th harmonic in some cases. The wave generation was studied for various magnetic fields and background plasma densities, as well as for different beam energies and pitch angles. The waves were measured with 3-axis electric and magnetic probes. Detailed measurements of the perpendicular mode structure will be shown. Langmuir probes were used to measure density and temperature evolution due to the beam-plasma interaction. Retarding field energy analyzers captured the ion beam profiles. The work was performed at the LArge Plasma Device at the Basic Plasma Science Facility (BaPSF) at UCLA, funded by DOE/NSF.

  2. CO-ANALYSIS OF SOLAR MICROWAVE AND HARD X-RAY SPECTRAL EVOLUTIONS. I. IN TWO FREQUENCY OR ENERGY RANGES

    International Nuclear Information System (INIS)

    Song Qiwu; Huang Guangli; Nakajima, Hiroshi

    2011-01-01

    Solar microwave and hard X-ray spectral evolutions are co-analyzed in the 2000 June 10 and 2002 April 10 flares, and are simultaneously observed by the Owens-Valley Solar Array in the microwave band and by Yohkoh/Hard X-ray Telescope or RHESSI in the hard X-ray band, with multiple subpeaks in their light curves. The microwave and hard X-ray spectra are fitted by a power law in two frequency ranges of the optical thin part and two photon energy ranges, respectively. Similar to an earlier event in Shao and Huang, the well-known soft-hard-soft pattern of the lower energy range changed to the hard-soft-hard (HSH) pattern of the higher energy range during the spectral evolution of each subpeak in both hard X-ray flares. This energy dependence is actually supported by a positive correlation between the overall light curves and spectral evolution in the lower energy range, while it becomes an anti-correlation in the higher energy range. Regarding microwave data, the HSH pattern appears in the spectral evolution of each subpeak in the lower frequency range, which is somewhat similar to Huang and Nakajima. However, it returns back to the well-known pattern of soft-hard-harder for the overall spectral evolution in the higher frequency range of both events. This frequency dependence is confirmed by an anti-correlation between the overall light curves and spectral evolution in the lower frequency range, but it becomes a positive correlation in the higher frequency range. The possible mechanisms are discussed, respectively, for reasons why hard X-ray and microwave spectral evolutions have different patterns in different energy and frequency intervals.

  3. Measurements with vertically viewing charge exchange analyzers during ion cyclotron range of frequencies heating in TFTR

    International Nuclear Information System (INIS)

    Kaita, R.; Hammett, G.W.; Gammel, G.; Goldston, R.J.; Medley, S.S.; Scott, S.D.; Young, K.M.

    1988-01-01

    The utility of charge exchange neutral particle analyzers for studying energetic ion distributions in high-temperature plasmas has been demonstrated in a variety of tokamak experiments. Power deposition profiles have been estimated in the Princeton large torus (PLT) from particle measurements as a function of energy and angle during heating in the ion cyclotron range of frequencies (ICRF) and extensive studies of this heating mode are planned for the upcoming operational period in the tokamak fusion test reactor (TFTR). Unlike the horizontally scanning analyzer on PLT, the TFTR system consists of vertical sightlines intersecting a poloidal cross section of the plasma. A bounce-averaged Fokker--Planck program, which includes a quasilinear operator to calculate ICRF-generated energetic ions, is used to simulate the charge exchange flux expected during fundamental hydrogen heating. These sightlines also cross the trajectory of a diagnostic neutral beam (DNB), and it may be possible to observe the fast ion tail during 3 He minority heating, if the DNB is operated in helium for double charge exchange neutralization

  4. Reexamining the frequency range of hearing in silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp

    Science.gov (United States)

    Vetter, Brooke J.; Brey, Marybeth; Meninger, Allen F.

    2018-01-01

    Silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp (collectively bigheaded carp) are invasive fish that threaten aquatic ecosystems in the upper Midwest United States and the Laurentian Great Lakes. Controlling bigheaded carp is a priority of fisheries managers and one area of focus involves developing acoustic deterrents to prevent upstream migration. For an acoustic deterrent to be effective however, the hearing ability of bigheaded carp must be characterized. A previous study showed that bigheaded carp detected sound up to 3 kHz but this range is narrower than what has been reported for other ostariophysans. Therefore, silver and bighead carp frequency detection was evaluated in response to 100 Hz to 9 kHz using auditory evoked potentials (AEPs). AEPs were recorded from 100 Hz to 5 kHz. The lowest thresholds were at 500 Hz for both species (silver carp threshold: 80.6 ± 3.29 dB re 1 μPa SPLrms, bighead carp threshold: 90.5 ± 5.75 dB re 1 μPa SPLrms; mean ± SD). These results provide fisheries managers with better insight on effective acoustic stimuli for deterrent systems, however, to fully determine bigheaded carp hearing abilities, these results need to be compared with behavioral assessments.

  5. An Obliquely Propagating Electromagnetic Drift Instability in the Lower Hybrid Frequency Range

    International Nuclear Information System (INIS)

    Hantao Ji; Russell Kulsrud; William Fox; Masaaki Yamada

    2005-01-01

    By employing a local two-fluid theory, we investigate an obliquely propagating electromagnetic instability in the lower hybrid frequency range driven by cross-field current or relative drifts between electrons and ions. The theory self-consistently takes into account local cross-field current and accompanying pressure gradients. It is found that the instability is caused by reactive coupling between the backward propagating whistler (fast) waves in the moving electron frame, and the forward propagating sound (slow) waves in the ion frame when the relative drifts are large. The unstable waves we consider propagate obliquely to the unperturbed magnetic field and have mixed polarization with significant electromagnetic components. A physical picture of the instability emerges in the limit of large wave number characteristic of the local approximation. The primary positive feedback mechanism is based on reinforcement of initial electron density perturbations by compression of electron fluid via induced Lorentz force. The resultant waves are qualitatively consistent with the measured electromagnetic fluctuations in reconnecting current sheet in a laboratory plasma

  6. Discriminating low frequency components from long range persistent fluctuations in daily atmospheric temperature variability

    Directory of Open Access Journals (Sweden)

    V. Cuomo

    2009-07-01

    Full Text Available This study originated from recent results reported in literature, which support the existence of long-range (power-law persistence in atmospheric temperature fluctuations on monthly and inter-annual scales. We investigated the results of Detrended Fluctuation Analysis (DFA carried out on twenty-two historical daily time series recorded in Europe in order to evaluate the reliability of such findings in depth. More detailed inspections emphasized systematic deviations from power-law and high statistical confidence for functional form misspecification. Rigorous analyses did not support scale-free correlation as an operative concept for Climate modelling, as instead suggested in literature. In order to understand the physical implications of our results better, we designed a bivariate Markov process, parameterised on the basis of the atmospheric observational data by introducing a slow dummy variable. The time series generated by this model, analysed both in time and frequency domains, tallied with the real ones very well. They accounted for both the deceptive scaling found in literature and the correlation details enhanced by our analysis. Our results seem to evidence the presence of slow fluctuations from another climatic sub-system such as ocean, which inflates temperature variance up to several months. They advise more precise re-analyses of temperature time series before suggesting dynamical paradigms useful for Climate modelling and for the assessment of Climate Change.

  7. ICRF [Ion Cyclotron Range of Frequencies] heating and antenna coupling in a high beta tokamak

    International Nuclear Information System (INIS)

    Elet, R.S.

    1988-01-01

    Maxwell's Equations are solved in two-dimensions for the electromagnetic fields in a toroidal cavity using the cold plasma fluid dielectric tensor in the Ion Cyclotron Range of Frequencies (ICRF). The Vector Wave Equation is transformed to a set of two, coupled second-order partial differential equations with inhomogeneous forcing functions which model a wave launcher. The resulting equations are finite differenced and solved numerically with a complex banded matrix algorithm on a Cray-2 computer using a code described in this report. This code is used to study power coupling characteristics of a wave launcher for low and high beta tokamaks. The low and high beta equilibrium tokamak magnetic fields applied in this model are determined from analytic solutions to the Grad-Shafranov equation. The code shows good correspondence with the results of low field side ICRF heating experiments performed on the Tokamak of Fontenay-Aux-Roses (TFR). Low field side and high field side antenna coupling properties for ICRF heating in the Columbia High Beta Tokamak (HBT) experiment are calculated with this code. Variations of antenna position in the tokamak, ionic concentration and plasma density, and volume-averaged beta have been analyzed for HBT. It is found that the location of the antenna with respect to the plasma has the dominant role in the design of an ICRF heating experiment in HBT. 10 refs., 52 figs., 13 tabs

  8. Development of disposable membrane hydrophones for a frequency range from 1MHz to 10MHz.

    Science.gov (United States)

    Lee, Jae-Wan; Ohm, Won-Suk; Kim, Yong-Tae

    2017-11-01

    A method for fabricating disposable membrane hydrophones is presented. The disposable hydrophones are intended for onetime use in such damaging environments as chemically contaminating fluids and high-amplitude (peak amplitude ∼100MPa) shock wave fields, where the use of commercial membrane hydrophones is not recommended. Fabrication of a hydrophone is done using only off-the-shelf components and hand tools, which translates into ease of fabrication and orders-of-magnitude reduction in unit cost. In particular, poling and sputtering, the two processes that are chiefly responsible for the cost and difficulty associated with the conventional fabrication method, are replaced with the use of pre-poled polyvinylidene fluoride (PVDF) films and polyethylene terephthalate (PET)-coated aluminum foils, respectively. Despite the seemingly crude construction, these disposable hydrophones can exhibit voltage sensitivity response that compares favorably with that of commercial hydrophones. For example, one prototype having a 2mm×2mm active element shows the end-of-cable voltage sensitivity of -270 (±1.9) dB re 1V/μPa over the frequency range of 1-10MHz. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Shifts in diversification rates and host jump frequencies shaped the diversity of host range among Sclerotiniaceae fungal plant pathogens

    OpenAIRE

    Taylor, Andrew; Clarkson, John; Raffaele, Sylvain; Navaud, Olivier; Barbacci, Adelin

    2017-01-01

    The range of hosts that a parasite can infect in nature is a trait determined by its own evolutionary history and that of its potential hosts. However, knowledge on host range diversity and evolution at the family level is often lacking. Here, we investigate host range variation and diversification trends within the Sclerotiniaceae , a family of Ascomycete fungi. Using a phylogenetic framework, we associate diversification rates, the frequency of host jump events, and host range variation dur...

  10. Two efficient methods for measuring hydrophone frequency response in the 100 kHz to 2 MHz range

    International Nuclear Information System (INIS)

    Harris, G R; Maruvada, S; Gammell, P M

    2004-01-01

    As new medical applications of ultrasound emerge with operating frequencies in the hundreds of kilohertz to low megahertz region, it becomes more important to have convenient calibration methods for hydrophones in this frequency range. Furthermore, short diagnostic ultrasound pulses affected by finite amplitude distortion require that the hydrophone frequency response be known well below the center frequency. National standards laboratories can provide accurate calibration data at these frequencies, but the two methods now employed, laser interferometry and three-transducer reciprocity, are both single-frequency techniques, and they can be time-consuming procedures. Therefore, two efficient methods for generating a wideband acoustic pressure spectrum have been implemented to cover this frequency range. In one method a high-voltage pulse generator was used to excite a thick piezoelectric ceramic disk, producing a plane-wave acoustic pressure transient <1 μs in duration with peak amplitude of about 40 kPa. In the other technique, time delay spectrometry (TDS), a purpose-built 1-3 piezoelectric composite source transducer weakly focused at 20 cm was swept over the 0-2 MHz range. Its transmitting voltage response at 1 MHz was 11 kPa/V. The broadband pulse technique has the advantage of being simpler to implement, but TDS has a much greater signal-to-noise ratio because of the frequency-swept narrowband filter employed

  11. Electromagnetic emission from terrestrial lightning in the 0.1-30 MHz frequency range

    Science.gov (United States)

    Karashtin, A. N.; Gurevich, A. V.

    Results of measurements carried out at SURA facility of Radiophisical Research Institute and at Tien-Shan Mountain Scientific Station of Lebedev Physical Institute using specially designed installations for short electromagnetic pulse observation in the frequency range from 0.1 to 30 MHz are presented. Specific attention is paid to initial stage of the lightning discharge. It is shown that lightning can be initiated by extensive atmospheric showers caused by high energy cosmic ray particles. Analysis of emission of few thousand lightning discharges showed that • Short wave radio emission of lightning consists of a series of short pulses with duration from less than 100 nanoseconds to several microseconds separated well longer gaps. • Background noise between lightning discharges is not differ from one observed without thunderstorm activity (at given sensitivity). Usually it is the same between lightning pulses at least at the initial stage. • Each lightning discharge radio emission starts with a number of very short (less than 100 nanoseconds at 0.7 level) bi-polar pulses. Gaps between initial pulses vary from several microseconds to few hundreds of microseconds. No radio emission was observed before the first pulse during at least 500 milliseconds. Both positive and negative polarity of the first pulses occur in approximately equal proportion in different lightning discharges while the polarity was the same in any individual lightning. • First pulse amplitude, width and waveform are consistent with predicted by the theory of combined action of runaway breakdown and extensive atmospheric shower caused by cosmic ray particle of 1016 eV energy. Lightning discharges at other planets can be initiated by cosmic ray particles as well. This work was partly supported by ISTC grant # 2236p. The work of one of the authors (A. N. Karashtin) was also partly supported by INTAS grant # 03-51-5727.

  12. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    Science.gov (United States)

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  13. Relationships between range access as monitored by radio frequency identification technology, fearfulness, and plumage damage in free-range laying hens.

    Science.gov (United States)

    Hartcher, K M; Hickey, K A; Hemsworth, P H; Cronin, G M; Wilkinson, S J; Singh, M

    2016-05-01

    Severe feather-pecking (SFP), a particularly injurious behaviour in laying hens (Gallus gallus domesticus), is thought to be negatively correlated with range use in free-range systems. In turn, range use is thought to be inversely associated with fearfulness, where fearful birds may be less likely to venture outside. However, very few experiments have investigated the proposed association between range use and fearfulness. This experiment investigated associations between range use (time spent outside), fearfulness, plumage damage, and BW. Two pens of 50 ISA Brown laying hens (n=100) were fitted with radio frequency identification (RFID) transponders (contained within silicone leg rings) at 26 weeks of age. Data were then collected over 13 days. A total of 95% of birds accessed the outdoor run more than once per day. Birds spent an average duration of 6.1 h outside each day over 11 visits per bird per day (51.5 min per visit). The top 15 and bottom 15 range users (n=30), as determined by the total time spent on the range over 13 days, were selected for study. These birds were tonic immobility (TI) tested at the end of the trial and were feather-scored and weighed after TI testing. Birds with longer TI durations spent less time outside (P=0.01). Plumage damage was not associated with range use (P=0.68). The small group sizes used in this experiment may have been conducive to the high numbers of birds utilising the outdoor range area. The RFID technology collected a large amount of data on range access in the tagged birds, and provides a potential means for quantitatively assessing range access in laying hens. The present findings indicate a negative association between fearfulness and range use. However, the proposed negative association between plumage damage and range use was not supported. The relationships between range use, fearfulness, and SFP warrant further research.

  14. Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges.

    Science.gov (United States)

    Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

    2018-04-01

    Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

  15. Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges

    Science.gov (United States)

    Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

    2018-04-01

    Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

  16. Numerical Investigation and Experimental Demonstration of Chaos from Two-Stage Colpitts Oscillator in the Ultrahigh Frequency Range

    DEFF Research Database (Denmark)

    Bumeliene, S.; Tamasevicius, A.; Mykolaitis, G.

    2006-01-01

    A hardware prototype of the two-stage Colpitts oscillator employing the microwave BFG520 type transistors with the threshold frequency of 9 GHz and designed to operate in the ultrahigh frequency range (300–1000 MHz) is described. The practical circuit in addition to the intrinsic two-stage oscill......A hardware prototype of the two-stage Colpitts oscillator employing the microwave BFG520 type transistors with the threshold frequency of 9 GHz and designed to operate in the ultrahigh frequency range (300–1000 MHz) is described. The practical circuit in addition to the intrinsic two......-stage oscillator contains an emitter follower acting as a buffer and minimizing the influence of the load. The circuit is investigated both numerically and experimentally. Typical phase portraits, Lyapunov exponents, Lyapunov dimension and broadband continuous power spectra are presented. The main advantage...

  17. The influence of interlayer exchange coupling in giant-magnetoresistive devices on spin diode effect in wide frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Ziętek, Sławomir, E-mail: zietek@agh.edu.pl; Skowroński, Witold; Wiśniowski, Piotr; Czapkiewicz, Maciej; Stobiecki, Tomasz [Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków (Poland); Ogrodnik, Piotr [Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków (Poland); Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warszawa (Poland); Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznań (Poland); Barnaś, Józef [Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznań (Poland); Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland)

    2015-09-21

    Spin diode effect in a giant magnetoresistive strip is measured in a broad frequency range, including resonance and off-resonance frequencies. The off-resonance dc signal is relatively strong and also significantly dependent on the exchange coupling between magnetic films through the spacer layer. The measured dc signal is described theoretically by taking into account magnetic dynamics induced by Oersted field created by an ac current flowing through the system.

  18. A theoretical study on directivity control of multiple-loudspeaker system with a quadrupole radiation pattern in low frequency range

    Science.gov (United States)

    Irwansyah, Kuse, Naoyuki; Usagawa, Tsuyoshi

    2017-08-01

    Directivity pattern of an ordinary loudspeaker becomes more directive at higher frequencies. However, because a single loudspeaker tends to radiate uniformly in all directions at low frequencies, reverberation from surrounding building walls may affect speech intelligibility when installing a multiple-loudspeaker system at crossroads. As an alternative, a sharply directive sound source is recommended to be used, but in many cases the directivity of an ordinary loudspeaker is less sharp at lower frequencies. Therefore, in order to overcome such a limitation, this paper discusses the possibility of using four loudspeakers under active control to realize a quadrupole radiation pattern in low frequency range. In this study, the radiation pattern of a primary loudspeaker and three secondary loudspeakers has been modelled. By placing the loudspeakers close together in the direction of 0°, 90°, 180°, and 270°, it was theoretically demonstrated that a quadrupole radiation pattern can be shaped in the target frequency range up to 600 Hz by simply controlling the directivity in three of four directions which are 45°, 135°, 225°, and 315°. Although, the radiation pattern model is far from realistic configurations and conditions, it is possible to realize a quadrupole radiation pattern in the low frequency range.

  19. Frequency Diverse Array Radar Cramér-Rao Lower Bounds for Estimating Direction, Range, and Velocity

    Directory of Open Access Journals (Sweden)

    Yongbing Wang

    2014-01-01

    Full Text Available Different from phased-array radar, frequency diverse array (FDA radar offers range-dependent beampattern and thus provides new application potentials. But there is a fundamental question: what estimation performance can achieve for an FDA radar? In this paper, we derive FDA radar Cramér-Rao lower bounds (CRLBs for estimating direction, range (time delay, and velocity (Doppler shift. Two different data models including pre- and postmatched filtering are investigated separately. As the FDA radar has range-angle coupling, we use a simple transmit subaperturing strategy which divides the whole array into two subarrays, each uses a distinct frequency increment. Assuming temporally white Gaussian noise and linear frequency modulated transmit signal, extensive simulation examples are performed. When compared to conventional phased-array radar, FDA can yield better CRLBs for estimating the direction, range, and velocity. Moreover, the impacts of the element number and frequency increment are also analyzed. Simulation results show that the CRLBs decrease with the increase of the elements number and frequency increment.

  20. Characterization of Definity™ Ultrasound Contrast Agent at Frequency Range of 5–15 MHz

    NARCIS (Netherlands)

    Faez, Telli; Goertz, David; de Jong, N.

    2011-01-01

    The status of vasa vasorum, which can be imaged using ultrasound contrast agents, is an indication for the progression of atherosclerosis. The preferred ultrasound frequency for this purpose is between 5 and 15 MHz. Therefore, it is essential to have knowledge about the acoustic properties of

  1. Extended parametric gain range in photonic crystal fibers with strongly frequency-dependent field distributions.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2014-08-15

    The parametric gain range of a degenerate four-wave mixing process is determined in the undepleted pump regime. The gain range is considered with and without taking the mode field distributions of the four-wave mixing components into account. It is found that the mode field distributions have to be included to evaluate the parametric gain correctly in dispersion-tailored speciality fibers and that mode profile engineering can provide a way to increase the parametric gain range.

  2. Bulk plasma rotation in the presence of waves in the ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Eriksson, L.G.; Noterdaeme, J.M.; Kirov, K.

    2003-01-01

    Experiments with directed ICRF waves have for the first time in JET demonstrated the influence of absorbed wave momentum on bulk plasma rotation. Resonating fast ions acted as an intermediary in this process, and the experiments therefore provided evidence for the effect of fast ions on the plasma rotation. Results from these experiments are reviewed together with results from ICRF heated plasmas with symmetric spectra in JET and Tore Supra. The relevance of different theoretical models is briefly considered. (author)

  3. Investigation of hopped frequency waveforms for range and velocity measurements of radar targets

    CSIR Research Space (South Africa)

    Kathree, U

    2015-10-01

    Full Text Available In the field of radar, High Range Resolution (HRR) profiles are often used to improve target tracking accuracy in range and to allow the radar system to produce an image of an object using techniques such as inverse synthetic aperture radar (ISAR...

  4. Extended parametric gain range in photonic crystal fibers with strongly frequency-dependent field distributions

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin

    2014-01-01

    The parametric gain range of a degenerate four-wave mixing process is determined in the undepleted pump regime. The gain range is considered with and without taking the mode field distributions of the four-wave mixing components into account. It is found that the mode field distributions have...

  5. Ion heating in the ion cyclotron range of frequencies in the Wisconsin Tokapole II

    International Nuclear Information System (INIS)

    Biddle, A.P.

    1980-06-01

    Ion temperatures of 75 eV, a doubling of the ohmic heating temperature in a normal discharge, have been achieved using the fast magnetosonic wave heating at the second, third, and fourth harmonics of the cyclotron frequency in a single component hydrogen plasma. The wave launching structure is a single turn, shielded, insulated loop which constitutes the inductor of the rf source tank circuit. Power levels of 800 kW have been applied to the plasma for periods of up to 1.1 milliseconds. Good agreement has been found between theory and experiment for loading and wave propagation in the plasma for m = 0 and m = +1 modes. Eigenmodes have been observed by peaking of both the rf wave amplitude and the loading of the oscillator, as well as by oscillator frequency shifts imposed by their passage

  6. Fiber optics frequency comb enabled linear optical sampling with operation wavelength range extension.

    Science.gov (United States)

    Liao, Ruolin; Wu, Zhichao; Fu, Songnian; Zhu, Shengnan; Yu, Zhe; Tang, Ming; Liu, Deming

    2018-02-01

    Although the linear optical sampling (LOS) technique is powerful enough to characterize various advanced modulation formats with high symbol rates, the central wavelength of a pulsed local oscillator (LO) needs to be carefully set according to that of the signal under test, due to the coherent mixing operation. Here, we experimentally demonstrate wideband LOS enabled by a fiber optics frequency comb (FOFC). Meanwhile, when the broadband FOFC acts as the pulsed LO, we propose a scheme to mitigate the enhanced sampling error arising in the non-ideal response of a balanced photodetector. Finally, precise characterizations of arbitrary 128 Gbps PDM-QPSK wavelength channels from 1550 to 1570 nm are successfully achieved, when a 101.3 MHz frequency spaced comb with a 3 dB spectral power ripple of 20 nm is used.

  7. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    Energy Technology Data Exchange (ETDEWEB)

    Drakakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kymakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Tzagkarakis, G.; Louloudakis, D.; Katharakis, M. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kenanakis, G. [Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas, Heraklion (Greece); Suchea, M.; Tudose, V. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Chemistry Faculty, “Al.I.Cuza” University of Iasi, Iasi (Romania); Koudoumas, E., E-mail: koudoumas@staff.teicrete.gr [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece)

    2017-03-15

    Highlights: • Optimum paint contents should be chosen so that homogeneous and uniform nanocomposite layers exist exhibiting effective electromagnetic shielding. • The electromagnetic shielding in the frequency range studied comes mainly from absorption and increases with frequency. • Reflection reduces with increasing frequency, the decrease rate being smaller than that of the increase in absorption. • The shielding efficiency depends on both conductivity and thickness, the first dependence being more pronounced. - Abstract: We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4–20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  8. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    International Nuclear Information System (INIS)

    Drakakis, E.; Kymakis, E.; Tzagkarakis, G.; Louloudakis, D.; Katharakis, M.; Kenanakis, G.; Suchea, M.; Tudose, V.; Koudoumas, E.

    2017-01-01

    Highlights: • Optimum paint contents should be chosen so that homogeneous and uniform nanocomposite layers exist exhibiting effective electromagnetic shielding. • The electromagnetic shielding in the frequency range studied comes mainly from absorption and increases with frequency. • Reflection reduces with increasing frequency, the decrease rate being smaller than that of the increase in absorption. • The shielding efficiency depends on both conductivity and thickness, the first dependence being more pronounced. - Abstract: We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4–20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  9. Wide-range frequency selectivity in an acoustic sensor fabricated using a microbeam array with non-uniform thickness

    International Nuclear Information System (INIS)

    Shintaku, Hirofumi; Kotera, Hidetoshi; Kobayashi, Takayuki; Zusho, Kazuki; Kawano, Satoyuki

    2013-01-01

    In this study, we have demonstrated the fabrication of a microbeam array (MBA) with various thicknesses and investigated the suitability it for an acoustic sensor with wide-range frequency selectivity. For this, an MBA composed of 64 beams, with thicknesses varying from 2.99–142 µm, was fabricated by using single gray-scale lithography and a thick negative photoresist. The vibration of the beams in air was measured using a laser Doppler vibrometer; the resonant frequencies of the beams were measured to be from 11.5 to 290 kHz. Lastly, the frequency range of the MBA with non-uniform thickness was 10.9 times that of the MBA with uniform thickness. (paper)

  10. Experimental demonstrations in audible frequency range of band gap tunability and negative refraction in two-dimensional sonic crystal.

    Science.gov (United States)

    Pichard, Hélène; Richoux, Olivier; Groby, Jean-Philippe

    2012-10-01

    The propagation of audible acoustic waves in two-dimensional square lattice tunable sonic crystals (SC) made of square cross-section infinitely rigid rods embedded in air is investigated experimentally. The band structure is calculated with the plane wave expansion (PWE) method and compared with experimental measurements carried out on a finite extend structure of 200 cm width, 70 cm depth and 15 cm height. The structure is made of square inclusions of 5 cm side with a periodicity of L = 7.5 cm placed inbetween two rigid plates. The existence of tunable complete band gaps in the audible frequency range is demonstrated experimentally by rotating the scatterers around their vertical axis. Negative refraction is then analyzed by use of the anisotropy of the equi-frequency surface (EFS) in the first band and of a finite difference time domain (FDTD) method. Experimental results finally show negative refraction in the audible frequency range.

  11. Brain states recognition during visual perception by means of artificial neural network in the different EEG frequency ranges

    Science.gov (United States)

    Musatov, V. Yu.; Runnova, A. E.; Andreev, A. V.; Zhuravlev, M. O.

    2018-04-01

    In the present paper, the possibility of classification by artificial neural networks of a certain architecture of ambiguous images is investigated using the example of the Necker cube from the experimentally obtained EEG recording data of several operators. The possibilities of artificial neural network classification of ambiguous images are investigated in the different frequency ranges of EEG recording signals.

  12. Low-Voltage, Low-Power, and Wide-Tuning-Range Ring-VCO for Frequency ΔΣ Modulator

    DEFF Research Database (Denmark)

    Tuan Vu, Cao; Wisland, Dag T.; Lande, Tor Sverre

    A low-voltage, low-power, and wide-tuning-range VCO which converts an analog input voltage to phase information for a frequency ΔΣ modulator is proposed in this paper. The VCO is based on a differential ring oscillator, which is improved with modified symmetric load and a positive feedback...

  13. A Fixed-Frequency Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Blaabjerg, Frede

    2017-01-01

    This paper proposes a new bidirectional resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant DC-DC converters, and meanwhile achieves high efficiency...... and characteristics of the proposed converter are analyzed. Finally, a 1-kW converter prototype is built and the experimental results verify the theoretical analyses....

  14. Wave propagation and absorption in the electron cyclotron frequency range for TCA and TCV machines

    International Nuclear Information System (INIS)

    Cardinali, A.

    1990-01-01

    The main theoretical aspects of the propagation and absorption of electron cyclotron frequency waves are reviewed and applied to TCA and TCV tokamak plasmas. In particular the electromagnetic cold dispersion relation is solved analytically and numerically in order to recall the basic properties of mode propagation and to calculate the ray-trajectories by means of geometric optics. A numerical code which integrates the coupled first order differential ray-equations, has been developed and applied to the cases of interest. (author) 4 figs., 23 refs

  15. High resolution kilometric range optical telemetry in air by radio frequency phase measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guillory, Joffray; García-Márquez, Jorge; Truong, Daniel; Wallerand, Jean-Pierre [Laboratoire Commun de Métrologie LNE-Cnam (LCM), LNE, 1 rue Gaston Boissier, 75015 Paris (France); Šmíd, Radek [Laboratoire Commun de Métrologie LNE-Cnam (LCM), LNE, 1 rue Gaston Boissier, 75015 Paris (France); Institute of Scientific Instruments of the CAS, Kralovopolska 147, 612 64 Brno (Czech Republic); Alexandre, Christophe [Centre d’Études et de Recherche en Informatique et Communications (CEDRIC), Cnam, 292 rue St-Martin, 75003 Paris (France)

    2016-07-15

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

  16. Third-harmonic entanglement and Einstein-Podolsky-Rosen steering over a frequency range of more than an octave

    Science.gov (United States)

    Olsen, M. K.

    2018-03-01

    The development of quantum technologies which use quantum states of the light field interacting with other systems creates a demand for such states over wide frequency ranges. In this work we compare the bipartite entanglement and Einstein-Podolsky-Rosen (EPR) -steering properties of the two different parametric schemes which produce third-harmonic optical fields from an input field at the fundamental frequency. The first scheme uses second harmonic cascaded with sum-frequency generation, while the second uses triply degenerate four- wave mixing, also known as direct third-harmonic generation. We find that both schemes produce continuous-variable bipartite entanglement and EPR steering over a frequency range which has previously been unobtainable. The direct scheme produces a greater degree of EPR steering, while the cascaded scheme allows for greater flexibility in having three available bipartitions, thus allowing for greater flexibility in the tailoring of light matter interfaces. There are also parameter regimes in both for which classical mean-field analyses fail to predict the mean-field solutions. Both schemes may be very useful for applications in quantum communication and computation networks, as well as providing for quantum interfaces between a wider range of light and atomic ensembles than is presently practicable.

  17. Complex magnetic susceptibility setup for spectroscopy in the extremely low-frequency range

    NARCIS (Netherlands)

    Kuipers, B.W.M.; Bakelaar, I.A.; Klokkenburg, M.; Erne, B.H.

    2008-01-01

    A sensitive balanced differential transformer was built to measure complex initial parallel magnetic susceptibility spectra in the 0.01–1000 Hz range. The alternating magnetic field can be chosen sufficiently weak that the magnetic structure of the samples is only slightly perturbed and the low

  18. Frontside-micromachined planar piezoresistive vibration sensor: Evaluating performance in the low frequency test range

    Directory of Open Access Journals (Sweden)

    Lan Zhang

    2014-01-01

    Full Text Available Using a surface piezoresistor diffusion method and front-side only micromachining process, a planar piezoresistive vibration sensor was successfully developed with a simple structure, lower processing cost and fewer packaging difficulties. The vibration sensor had a large sector proof mass attached to a narrow flexure. Optimization of the boron diffusion piezoresistor placed on the edge of the narrow flexure greatly improved the sensitivity. Planar vibration sensors were fabricated and measured in order to analyze the effects of the sensor dimensions on performance, including the values of flexure width and the included angle of the sector. Sensitivities of fabricated planar sensors of 0.09–0.46 mV/V/g were measured up to a test frequency of 60 Hz. The sensor functioned at low voltages (<3 V and currents (<1 mA with a high sensitivity and low drift. At low background noise levels, the sensor had performance comparable to a commercial device.

  19. Frontside-micromachined planar piezoresistive vibration sensor: Evaluating performance in the low frequency test range

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lan; Lu, Jian, E-mail: jian-lu@aist.go.jp; Takagi, Hideki; Maeda, Ryutaro [Research Center for Ubiquitous MEMS and Micro Engineering (UMEMSME), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8564 (Japan)

    2014-01-15

    Using a surface piezoresistor diffusion method and front-side only micromachining process, a planar piezoresistive vibration sensor was successfully developed with a simple structure, lower processing cost and fewer packaging difficulties. The vibration sensor had a large sector proof mass attached to a narrow flexure. Optimization of the boron diffusion piezoresistor placed on the edge of the narrow flexure greatly improved the sensitivity. Planar vibration sensors were fabricated and measured in order to analyze the effects of the sensor dimensions on performance, including the values of flexure width and the included angle of the sector. Sensitivities of fabricated planar sensors of 0.09–0.46 mV/V/g were measured up to a test frequency of 60 Hz. The sensor functioned at low voltages (<3 V) and currents (<1 mA) with a high sensitivity and low drift. At low background noise levels, the sensor had performance comparable to a commercial device.

  20. High power heating in the ion cyclotron range of frequencies in the Wisconsin Tokapole II

    International Nuclear Information System (INIS)

    Biddle, A.P.; Sprott, J.C.

    1981-01-01

    Fast wave heating at the second, third and fourth harmonics of the ion cyclotron resonance, and slow wave heating at the fundamental in a single ion species hydrogen plasma, are found to be in good agreement with warm plasma theory at rf power levels <= 130 kW. Ion heating is negligible off an eigenmode. Ion body temperatures are more than doubled to 75 eV from the 35 eV ohmically heated case with tails comprising 8% of the plasma at 320 eV. No deleterious effects except a non-disruptive 10% shortening of the discharge length caused by impurity influx are noted. A passive mode tracking technique allows approximately equal to 40% increase in power deposition in a passing eigenmode over that of a fixed frequency rf source. Ion temperatures are limited by charge exchange due to the < 50 eV central temperature and the small 13 cm radius current channel. (author)

  1. An Efficient Framework for Analysis of Wire-Grid Shielding Structures over a Broad Frequency Range

    Directory of Open Access Journals (Sweden)

    A. Karwowski

    2016-12-01

    Full Text Available A computationally efficient MoM-based framework for broadband electromagnetic simulation of wire-grid shielding structures is presented in the paper. Broadband capability of the approach is attained through supporting MoM by an adaptive frequency sweep combined with rational interpolation of the observable implemented via Stoer-Bulirsch algorithm. The performance increase is gained by employing CUDA-enabled CPU+GPU co-processing. For large-size problems exceeding the amount of memory available on the GPU device, a hybrid out-of-GPU memory LU decomposition algorithm is employed. The demonstration examples are provided to illustrate the the accuracy and high efficiency of the approach.

  2. Controlled X-ray pumping in a wide range of piezo-electric oscillation frequencies

    CERN Document Server

    Navasardyan, M A; Galoyan, K G

    1986-01-01

    In case of Laue diffraction the transmitted X-ray reflection in shown to be effectively controllable in the perfect quartz single crystal when it generates ultrasonic oscillations at the resonance frequency or in its vicinity. The maximum effective amplitude of applied sinusoidal oscillations is equal to 70 V. The pumping degree depends on the voltage amplitude. In this work monochromatic K subalpha sub 1 and K subalpha sub 2 molybdenum lines satisfying the thin crystal condition, mu t<=1, are used (mu is the linear absorption coefficient of the sample for the given wavelength and t is its thickness). The radiation was reflected from different planes such as (1011), (1011), (2022) etc. The complete pumping strongly restricts the structural factor possibilities in estimating the intensity of diffracted X-rays in case of considerable deformations in the bulk of perfect single crystal.

  3. Optimal Design of a High Efficiency LLC Resonant Converter with a Narrow Frequency Range for Voltage Regulation

    Directory of Open Access Journals (Sweden)

    Junhao Luo

    2018-05-01

    Full Text Available As a key factor in the design of a voltage-adjustable LLC resonant converter, frequency regulation range is very important to the optimization of magnetic components and efficiency improvement. This paper presents a novel optimal design method for LLC resonant converters, which can narrow the frequency variation range and ensure high efficiency under the premise of a required gain achievement. A simplified gain model was utilized to simplify the calculation and the expected efficiency was initially set as 96.5%. The restricted area of parameter optimization design can be obtained by taking the intersection of the gain requirement, the efficiency requirement, and three restrictions of ZVS (Zero Voltage Switch. The proposed method was verified by simulation and experiments of a 150 W prototype. The results show that the proposed method can achieve ZVS from full-load to no-load conditions and can reach 1.6 times the normalized voltage gain in the frequency variation range of 18 kHz with a peak efficiency of up to 96.3%. Moreover, the expected efficiency is adjustable, which means a converter with a higher efficiency can be designed. The proposed method can also be used for the design of large-power LLC resonant converters to obtain a wide output voltage range and higher efficiency.

  4. Complex permeability and permittivity variation of carbonyl iron rubber in the frequency range of 2 to 18 GHz

    Directory of Open Access Journals (Sweden)

    Adriana Medeiros Gama

    2010-04-01

    Full Text Available The complex dielectric permittivity (e and magnetic permeability (m of Radar Absorbing Materials (RAM based on metallic magnetic particles (carbonyl iron particles embedded in a dielectric matrix (silicon rubber have been studied in the frequency range of 2 to 18 GHz. The relative permeability and permittivity of carbonyl iron-silicon composites for various mass fractions are measured by the transmission/reflection method using a vector network analyzer. The concentration dependence of permittivity and permeability on the frequency is analyzed. In a general way, the results show that e´ parameter shows a more significant variation among the evaluated parameters (e”, m”, m’. The comparison of dielectric and magnetic loss tangents (e”/e” and m”/m’, respectively shows more clearly the variation of both parameters (e and m according to the frequency. It is also observed that higher carbonyl iron content fractions favor both dielectric and magnetic loss tangents.

  5. Preparation, crystal structure, and dielectric characterization of Li2W2O7 ceramic at RF and microwave frequency range

    Directory of Open Access Journals (Sweden)

    Jinwu Chen

    2017-02-01

    Full Text Available Single phase Li2W2O7 with anorthic structure was prepared by the conventional solid-state reaction method at 550∘C and the anorthic structure was stable up to 660∘C. The dielectric properties at radio frequency (RF and microwave frequency range were characterized. The sample sintered at 640∘C exhibited the optimum microwave dielectric properties with a relative permittivity of 12.2, a quality factor value of 17,700GHz (at 9.8GHz, and a temperature coefficient of the resonant frequency of −232ppm/∘C as well as a high relative density ∼94.1%. Chemical compatibility measurement indicated Li2W2O7 did not react with aluminum electrodes when sintered at 640∘C for 4h.

  6. Pipe damping: experimental results from laboratory tests in the seismic frequency range

    International Nuclear Information System (INIS)

    Ware, A.G.; Arendts, J.G.

    1986-06-01

    The Idaho National Engineering Laboratory (INEL) has been conducting a research program to assist the United States Nuclear Regulatory Commission (USNRC) in determining best-estimate damping values for the seismic analysis of nuclear piping systems. As part of this program, a 5-in. piping system was tested by the INEL, and data from USNRC/EPRI piping vibration tests at the ANCO Engineers facility were evaluated. These systems were subjected to various types of excitation methods and magnitudes, the support configurations were varied, and the effects of pipe insulation and internal pressure were investigated on the INEL system. The INEL has used several different methods to reduce the data to determine the damping in both these piping systems under the various test conditions. It was concluded that at representative seismic excitation levels, pressure was not a contributing factor, but the supports, insulation, and magnitude of response all were major influences contributing to damping. These tests are part of the ongoing program to determine how various parameters and data reduction methods affect piping system damping. The evaluation of all relevant test results, including these two series, will potentially lead to revised damping guidelines for the seismic analysis of nuclear plants, making them safer, less costly, and easier to inspect and maintain. The test results as well as accompanying evaluations and recommendations are presented in this report. 27 refs., 72 figs., 13 tabs

  7. Prospective observational study on assessing the hemodynamic relevance of patent ductus arteriosus with frequency domain near-infrared spectroscopy.

    Science.gov (United States)

    Schwarz, Christoph E; Preusche, Antonio; Wolf, Martin; Poets, Christian F; Franz, Axel R

    2018-02-16

    What constitutes a hemodynamically relevant patent ductus arteriosus (hrPDA) in preterm infants is unclear. Different clinical and echocardiographic parameters are used, but a gold standard definition is lacking. Our objective was to evaluate associations between regional cerebral tissue oxygen saturation (rcStO 2 ), fraction of tissue oxygen extraction (rcFtO 2 E) measured by frequency domain near-infrared spectroscopy (fd-NIRS) and their correlation to echocardiographic, Doppler-ultrasound, and clinical parameters in preterm infants with and without a hrPDA. In this prospective observational study, 22 infants standard deviation (normalised to a median Hb of 13.8 mg/dl) was 57 ±5% for rcStO 2 and 0.39 ±0.05 for rcFtO 2 E. Comparing no-hrPDA with hrPDA infants, there were no significant differences in mean rcStO 2 (58 ±5% vs. 54 ±5%; p = .102), but in mean rcFtO 2 E (0.38 ±0.05 vs. 0.43 ±0.05; p = .038). Echocardiographic parameter and Doppler indices did not correlate with cerebral oxygenation. Oxygen transport capacity of the blood may confound NIRS data interpretation. Cerebral oxygenation determined by fd-NIRS provided additional information for PDA treatment decisions not offered by routine investigations. Whether indicating PDA therapy based on echocardiography complemented by data on cerebral oxygenation results in better outcomes should be investigated in future studies.

  8. Spindle disturbances in human-hamster hybrid (AL) cells induced by mobile communication frequency range signals.

    Science.gov (United States)

    Schrader, Thorsten; Münter, Klaus; Kleine-Ostmann, Thomas; Schmid, Ernst

    2008-12-01

    The production of spindle disturbances in FC2 cells, a human-hamster hybrid (A(L)) cell line, by non-ionizing radiation was studied using an electromagnetic field with a field strength of 90 V/m at a frequency of 835 MHz. Due to the given experimental conditions slide flask cultures were exposed at room temperature in a microTEM (transversal electromagnetic field) cell, which allows optimal experimental conditions for small samples of biological material. Numerical calculations suggest that specific absorption rates of up to 60 mW/kg are reached for maximum field exposure. All exposure field parameters--either measured or calculable--are precisely defined and, for the first time, traceable to the standards of the SI system of physical units. Compared with co-incident negative controls, the results of two independently performed experiments suggest that exposure periods of time from 0.5 to 2 h with an electric field strength of 90 V/m are spindle acting agents as predominately indicated by the appearance of spindle disturbances at the ana- and telophase stages (especially lagging and non-disjunction of single chromosomes) of cell divisions. The spindle disturbances do not change the fraction of mitotic cells with increasing exposure time up to 2 h. Due to the applied experimental conditions an influence of temperature as a confounder parameter for spindle disturbances can be excluded.

  9. Dynamic Confinement of ITER Plasma by O-Mode Driver at Electron Cyclotron Frequency Range

    Science.gov (United States)

    Stefan, V. Alexander

    2009-05-01

    A low B-field side launched electron cyclotron O-Mode driver leads to the dynamic rf confinement, in addition to rf turbulent heating, of ITER plasma. The scaling law for the local energy confinement time τE is evaluated (τE ˜ 3neTe/2Q, where (3/2) neTe is the local plasma thermal energy density and Q is the local rf turbulent heating rate). The dynamics of unstable dissipative trapped particle modes (DTPM) strongly coupled to Trivelpiece-Gould (T-G) modes is studied for gyrotron frequency 170GHz; power˜24 MW CW; and on-axis B-field ˜ 10T. In the case of dynamic stabilization of DTPM turbulence and for the heavily damped T-G modes, the energy confinement time scales as τE˜(I0)-2, whereby I0(W/m^2) is the O-Mode driver irradiance. R. Prater et. al., Nucl. Fusion 48, No 3 (March 2008). E. P. Velikhov, History of the Russian Tokamak and the Tokamak Thermonuclear Fusion Research Worldwide That Led to ITER (Documentary movie; Stefan Studios Int'l, La Jolla, CA, 2008; E. P. Velikhov, V. Stefan.) M N Rosenbluth, Phys. Scr. T2A 104-109 1982 B. B. Kadomtsev and O. P. Pogutse, Nucl. Fusion 11, 67 (1971).

  10. Interaction of electromagnetic radiation with magnetically functionalized CNT nanocomposite in the subterahertz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Atdaev, A.; Danilyuk, A. L.; Labunov, V. A.; Prischepa, S. L., E-mail: prischepa@bsuir.by [Belarusian State University of Informatics and Radioelectronics (Belarus); Pavlov, A. A. [Russian Academy of Sciences, Institute of Microelectronics Nanotechnologies (Russian Federation); Basaev, A. S.; Shaman, Yu. P. [SMC Technological Center (Russian Federation)

    2016-12-15

    The interaction of electromagnetic radiation with a magnetically functionalized nanocomposite based on carbon nanotubes (CNTs) is considered using the model of random distribution of ferromagnetic nanoparticles in the carbon matrix characterized by the presence of resistive–inductive–capacitive coupling (contours). The model is based on the representation of the nanocomposite as a system consisting of the CNT matrix, ferromagnetic nanoparticles, and the interfaces between CNTs and nanoparticles. The wide range of possible resonant phenomena caused both by the presence of contours and the properties of the CNT nanocomposite is shown.

  11. Excitation and propagation of electromagnetic fluctuations with ion-cyclotron range of frequency in magnetic reconnection laboratory experiment

    International Nuclear Information System (INIS)

    Inomoto, Michiaki; Tanabe, Hiroshi; Ono, Yasushi; Kuwahata, Akihiro

    2013-01-01

    Large-amplitude electromagnetic fluctuations of ion-cyclotron-frequency range are detected in a laboratory experiment inside the diffusion region of a magnetic reconnection with a guide field. The fluctuations have properties similar to kinetic Alfvén waves propagating obliquely to the guide field. Temporary enhancement of the reconnection rate is observed during the occurrence of the fluctuations, suggesting a relationship between the modification in the local magnetic structure given by these fluctuations and the intermittent fast magnetic reconnection

  12. The asymmetry of the entrainment range induced by the difference in intrinsic frequencies between two subgroups within the suprachiasmatic nucleus

    Science.gov (United States)

    Gu, Changgui; Yang, Huijie

    2017-06-01

    The rhythms of physiological and behavioral activities in mammals, which are regulated by the main clock suprachiasmatic nucleus (SCN) in the brain, can not be only synchronized to the natural 24 h light-dark cycle, but also to cycles with artificial periods. The range of the artificial periods that the animal can be synchronized to is called entrainment range. In the absence of the light-dark cycle, the animal can also maintain the circadian rhythm with an endogenous period close to 24 h. Experiments found that the entrainment range is not symmetrical with respect to the endogenous period. In the present study, an explanation is given for the asymmetry based on a Kuramoto model which describes the neuronal network of the SCN. Our numerical simulations and theoretical analysis show that the asymmetry results from the difference in the intrinsic frequencies between two subgroups of the SCN, as well as the entrainment range is affected by the difference.

  13. Application range affected by software failures in safety relevant instrumentation and control systems of nuclear power plants

    International Nuclear Information System (INIS)

    Jopen, Manuela; Mbonjo, Herve; Sommer, Dagmar; Ulrich, Birte

    2017-03-01

    This report presents results that have been developed within a BMUB-funded research project (Promotion Code 3614R01304). The overall objective of this project was to broaden the knowledge base of GRS regarding software failures and their impact in software-based instrumentation and control (I and C) systems. To this end, relevant definitions and terms in standards and publications (DIN, IEEE standards, IAEA standards, NUREG publications) as well as in the German safety requirements for nuclear power plants were analyzed first. In particular, it was found that the term ''software fault'' is defined differently and partly contradictory in the considered literature sources. For this reason, a definition of software fault was developed on the basis of the software life cycle of software-based I and C systems within the framework of this project, which takes into account the various aspects relevant to software faults and their related effects. It turns out that software failures result from latent faults in a software-based control system, which can lead to a non-compliant behavior of a software-based I and C system. Hereby a distinction should be made between programming faults and specification faults. In a further step, operational experience with software failures in software-based I and C systems in nuclear facilities and in nonnuclear sector was investigated. The identified events were analyzed with regard to their cause and impacts and the analysis results were summarized. Based on the developed definition of software failure and on the COMPSIS-classification scheme for events related to software based I and C systems, the COCS-classification scheme was developed to classify events from operating experience with software failures, in which the events are classified according to the criteria ''cause'', ''affected system'', ''impact'' and ''CCF potential''. This classification scheme was applied to evaluate the events identified in the framework of this project

  14. Recent ion cyclotron range of frequencies experiments in JT-60U

    International Nuclear Information System (INIS)

    Kimura, H.; Fujii, T.; Saigusa, M.; Moriyama, S.; Sato, M.; Nemoto, M.; Kondoh, T.; Hamamatsu, K.

    1995-01-01

    Recent results on the minority ion second harmonic heating on JT-60U are presented. Maximum coupled power reached 6.4MW. Good antenna-plasma coupling capability and a small fraction (less than 10%) of an incremental radiation loss to r.f. power are confirmed. Power absorption rate increases with increasing r.f. power and is saturated around unity at r.f. powers higher than 3MW. The sawtooth stabilization by minority ion second harmonic heating was realized over a wide parameter range, i.e. I P =0.9MA-4MA, q 95 =2.3-8.6, n e =(1.3-5)x10 19 m -3 and P IC ≥2.2MW. A figure of merit V P left angle n e right angle /P tot for efficiency of the sawtooth stabilization is about 50% higher than those in other devices where fundamental resonance minority ion heating is employed. The longest stable period reached 2.33s. Attainable sawtooth-free periods scale with the resistive diffusion time. It was found that the energy confinement is further improved by 25% during the reheating phase after the giant sawtooth crash. The electron temperature profile became more peaked at the improved confinement phase. Those phenomena were observed only in low q discharges (q 95 ≤2.9). ((orig.))

  15. Laboratory piping system vibration tests to determine parametric effects on damping in the seismic frequency range

    International Nuclear Information System (INIS)

    Ware, A.G.

    1987-01-01

    A pipe damping research program is being conducted for the United States Nuclear Regulatory Commission at the Idaho National Engineering Laboratory to establish more realistic, best-estimate damping values for use in dynamic structural analyses of piping systems. As part of this program, tests were conducted on a 5-in. (128 mm ID) laboratory piping system to determine the effects of pressure, support configuration, insulation and response amplitude on damping. The tests were designed to produce a wide range of damping values, from very low damping in lightly excited uninsulated systems with few supports, to higher damping under conditions of either/or insulation, high level excitation, and various support arrangements. The effect of pressure at representative seismic levels was considered to be minimal. The supports influence damping at all excitation levels; damping was highest when a mechanical snubber was present in the system. The addition of insulation produced a large increase in damping for the hydraulic shaker excitation tests, but there was no comparable increase for the snapback excitation tests. Once a response amplitude of approximately one-half yield stress was reached, overall damping increased to relatively high levels (>10% of critical)

  16. A Technique for Real-Time Ionospheric Ranging Error Correction Based On Radar Dual-Frequency Detection

    Science.gov (United States)

    Lyu, Jiang-Tao; Zhou, Chen

    2017-12-01

    Ionospheric refraction is one of the principal error sources for limiting the accuracy of radar systems for space target detection. High-accuracy measurement of the ionospheric electron density along the propagation path of radar wave is the most important procedure for the ionospheric refraction correction. Traditionally, the ionospheric model and the ionospheric detection instruments, like ionosonde or GPS receivers, are employed for obtaining the electron density. However, both methods are not capable of satisfying the requirements of correction accuracy for the advanced space target radar system. In this study, we propose a novel technique for ionospheric refraction correction based on radar dual-frequency detection. Radar target range measurements at two adjacent frequencies are utilized for calculating the electron density integral exactly along the propagation path of the radar wave, which can generate accurate ionospheric range correction. The implementation of radar dual-frequency detection is validated by a P band radar located in midlatitude China. The experimental results present that the accuracy of this novel technique is more accurate than the traditional ionospheric model correction. The technique proposed in this study is very promising for the high-accuracy radar detection and tracking of objects in geospace.

  17. Digital predistortion of 75–110 GHz W-band frequency multiplier for fiber wireless short range access systems

    DEFF Research Database (Denmark)

    Zhao, Ying; Deng, Lei; Pang, Xiaodan

    2011-01-01

    be effectively pre-compensated. Without using costly W-band components, a transmission system with 26km fiber and 4m wireless transmission operating at 99.6GHz is experimentally validated. Adjacent-channel power ratio (ACPR) improvements for IQ-modulated vector signals are guaranteed and transmission......We present a W-band fiber-wireless transmission system based on a nonlinear frequency multiplier for high-speed wireless short range access applications. By implementing a baseband digital signal predistortion scheme, intensive nonlinear distortions induced in a sextuple frequency multiplier can...... performances for fiber and wireless channels are studied. This W-band predistortion technique is a promising candidate for applications in high capacity wireless-fiber access systems....

  18. Prediction of rain effects on earth-space communication links operating in the 10 to 35 GHz frequency range

    Science.gov (United States)

    Stutzman, Warren L.

    1989-01-01

    This paper reviews the effects of precipitation on earth-space communication links operating the 10 to 35 GHz frequency range. Emphasis is on the quantitative prediction of rain attenuation and depolarization. Discussions center on the models developed at Virginia Tech. Comments on other models are included as well as literature references to key works. Also included is the system level modeling for dual polarized communication systems with techniques for calculating antenna and propagation medium effects. Simple models for the calculation of average annual attenuation and cross-polarization discrimination (XPD) are presented. Calculation of worst month statistics are also presented.

  19. Structural partitioning of complex structures in the medium-frequency range. An application to an automotive vehicle

    Science.gov (United States)

    Kassem, M.; Soize, C.; Gagliardini, L.

    2011-02-01

    In a recent work [ Journal of Sound and Vibration 323 (2009) 849-863] the authors presented an energy-density field approach for the vibroacoustic analysis of complex structures in the low and medium frequency ranges. In this approach, a local vibroacoustic energy model as well as a simplification of this model were constructed. In this paper, firstly an extension of the previous theory is performed in order to include the case of general input forces and secondly, a structural partitioning methodology is presented along with a set of tools used for the construction of a partitioning. Finally, an application is presented for an automotive vehicle.

  20. ICRF [ion cyclotron range of frequencies] coupling on DIII-D and the implications on ICRF technology development

    International Nuclear Information System (INIS)

    Hoffman, D.J.; Baity, F.W.; Mayberry, M.J.; Swain, D.W.

    1987-01-01

    Low-power coupling tests have been carried out with a prototype ion cyclotron range of frequencies (ICRF) compact loop antenna on the DIII-D tokamak. Plasma load resistance values higher than originally calculated are measured in ohmic and L-mode, beam-heated plasmas. Load resistance decreases by a factor of ∼2 in H-mode operation. When edge localized modes (ELMs) occur, the antenna loading increases transiently to several ohms. Results indicate that fast-wave ICRF antenna coupling characteristics are highly sensitive to changes in the edge plasma profiles associated with the H-mode regime

  1. Fourier domain optical coherence tomography achieves full range complex imaging in vivo by introducing a carrier frequency during scanning

    International Nuclear Information System (INIS)

    Wang, Ruikang K

    2007-01-01

    The author describes a Fourier domain optical coherence tomography (FDOCT) system that is capable of full range complex imaging in vivo. This is achieved by introducing a constant carrier frequency into the OCT spectral interferograms at the time when imaging is performed. The complex functions of the spatial interferograms formed by each single wavelength are constructed before performing the Fourier transformation to localize the scatters within a sample. Two algorithms, based on Fourier filtering and Hilbert transformation, respectively, are described to achieve the full range complex FDOCT imaging. It is shown that the Hilbert transformation approach delivers better performance than the Fourier filtering method does in terms of tolerating the sample movement in vivo. The author finally demonstrates experimentally the system and algorithms for true in vivo imaging at a rate of 20 000 axial scans per second

  2. Effects of sample size and sampling frequency on studies of brown bear home ranges and habitat use

    Science.gov (United States)

    Arthur, Steve M.; Schwartz, Charles C.

    1999-01-01

    We equipped 9 brown bears (Ursus arctos) on the Kenai Peninsula, Alaska, with collars containing both conventional very-high-frequency (VHF) transmitters and global positioning system (GPS) receivers programmed to determine an animal's position at 5.75-hr intervals. We calculated minimum convex polygon (MCP) and fixed and adaptive kernel home ranges for randomly-selected subsets of the GPS data to examine the effects of sample size on accuracy and precision of home range estimates. We also compared results obtained by weekly aerial radiotracking versus more frequent GPS locations to test for biases in conventional radiotracking data. Home ranges based on the MCP were 20-606 km2 (x = 201) for aerial radiotracking data (n = 12-16 locations/bear) and 116-1,505 km2 (x = 522) for the complete GPS data sets (n = 245-466 locations/bear). Fixed kernel home ranges were 34-955 km2 (x = 224) for radiotracking data and 16-130 km2 (x = 60) for the GPS data. Differences between means for radiotracking and GPS data were due primarily to the larger samples provided by the GPS data. Means did not differ between radiotracking data and equivalent-sized subsets of GPS data (P > 0.10). For the MCP, home range area increased and variability decreased asymptotically with number of locations. For the kernel models, both area and variability decreased with increasing sample size. Simulations suggested that the MCP and kernel models required >60 and >80 locations, respectively, for estimates to be both accurate (change in area bears. Our results suggest that the usefulness of conventional radiotracking data may be limited by potential biases and variability due to small samples. Investigators that use home range estimates in statistical tests should consider the effects of variability of those estimates. Use of GPS-equipped collars can facilitate obtaining larger samples of unbiased data and improve accuracy and precision of home range estimates.

  3. The dielectric properties of human pineal gland tissue and RF absorption due to wireless communication devices in the frequency range 400-1850 MHz

    International Nuclear Information System (INIS)

    Schmid, Gernot; Ueberbacher, Richard; Samaras, Theodoros; Tschabitscher, Manfred; Mazal, Peter R

    2007-01-01

    In order to enable a detailed analysis of radio frequency (RF) absorption in the human pineal gland, the dielectric properties of a sample of 20 freshly removed pineal glands were measured less than 20 h after death. Furthermore, a corresponding high resolution numerical model of the brain region surrounding the pineal gland was developed, based on a real human tissue sample. After inserting this model into a commercially available numerical head model, FDTD-based computations for exposure scenarios with generic models of handheld devices operated close to the head in the frequency range 400-1850 MHz were carried out. For typical output power values of real handheld mobile communication devices, the obtained results showed only very small amounts of absorbed RF power in the pineal gland when compared to SAR limits according to international safety standards. The highest absorption was found for the 400 MHz irradiation. In this case the RF power absorbed inside the pineal gland (organ mass 96 mg) was as low as 11 μW, when considering a device of 500 mW output power operated close to the ear. For typical mobile phone frequencies (900 MHz and 1850 MHz) and output power values (250 mW and 125 mW) the corresponding values of absorbed RF power in the pineal gland were found to be lower by a factor of 4.2 and 36, respectively. These results indicate that temperature-related biologically relevant effects on the pineal gland induced by the RF emissions of typical handheld mobile communication devices are unlikely

  4. Fully automated dual-frequency three-pulse-echo 2DIR spectrometer accessing spectral range from 800 to 4000 wavenumbers

    Energy Technology Data Exchange (ETDEWEB)

    Leger, Joel D.; Nyby, Clara M.; Varner, Clyde; Tang, Jianan; Rubtsova, Natalia I.; Yue, Yuankai; Kireev, Victor V.; Burtsev, Viacheslav D.; Qasim, Layla N.; Rubtsov, Igor V., E-mail: irubtsov@tulane.edu [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Rubtsov, Grigory I. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312 (Russian Federation)

    2014-08-15

    A novel dual-frequency two-dimensional infrared instrument is designed and built that permits three-pulse heterodyned echo measurements of any cross-peak within a spectral range from 800 to 4000 cm{sup −1} to be performed in a fully automated fashion. The superior sensitivity of the instrument is achieved by a combination of spectral interferometry, phase cycling, and closed-loop phase stabilization accurate to ∼70 as. The anharmonicity of smaller than 10{sup −4} cm{sup −1} was recorded for strong carbonyl stretching modes using 800 laser shot accumulations. The novel design of the phase stabilization scheme permits tuning polarizations of the mid-infrared (m-IR) pulses, thus supporting measurements of the angles between vibrational transition dipoles. The automatic frequency tuning is achieved by implementing beam direction stabilization schemes for each m-IR beam, providing better than 50 μrad beam stability, and novel scheme for setting the phase-matching geometry for the m-IR beams at the sample. The errors in the cross-peak amplitudes associated with imperfect phase matching conditions and alignment are found to be at the level of 20%. The instrument can be used by non-specialists in ultrafast spectroscopy.

  5. An algorithm for the calculation of 3-D ICRF [Ion Cyclotron Range of Frequencies] fields in tokamak geometry

    International Nuclear Information System (INIS)

    Smithe, D.N.; Colestock, P.L.; Kashuba, R.J.; Kammash, T.

    1987-04-01

    A computational scheme is developed which permits tractable calculation of three-dimensional full-wave solutions to the Maxwell-Vlasov equations under typical Ion Cyclotron Range of Frequencies (ICRF) experimental conditions. The method is unique in that power deposition to the plasma is determined via the anti-Hermitian part of a truncated warm-plasma dielectric operator, rather than as the result of an assumed phenomenological collision frequency. The resulting computer code allows arbitrary variation of density, temperature, magnetic field, and minority concentration in the poloidal plane by performing a convolution of poloidal modes to produce a coupled system of differential equations in the radial variable. By assuming no inhomogeneity along the toroidal axis, an inverse transform over k/sub parallel/ is performed to yield the full three-dimensional field solutions. The application of the code to TFTR-like plasmas shows a mild resonance structure in antenna loading related to the changing number of wavelengths between antenna and the resonance layer. 48 figs

  6. Computational dosimetry in embryos exposed to electromagnetic plane waves over the frequency range of 10 MHz-1.5 GHz

    International Nuclear Information System (INIS)

    Kawai, Hiroki; Nagaoka, Tomoaki; Watanabe, Soichi; Saito, Kazuyuki; Takahashi, Masaharu; Ito, Koichi

    2010-01-01

    This paper presents calculated specific absorption rate (SAR) dosimetry in 4 and 8 week Japanese pregnant-woman models exposed to plane waves over the frequency range of 10 MHz-1.5 GHz. Two types of 2 mm spatial-resolution pregnant-woman models comprised a woman model, which is similar to the average-sized Japanese adult female in height and weight, with a cubic (4 week) embryo or spheroidal (8 week) one. The averaged SAR in the embryos exposed to vertically and horizontally polarized plane waves at four kinds of propagation directions are calculated from 10 MHz to 1.5 GHz. The results indicate that the maximum average SAR in the embryos exposed to plane waves is lower than 0.08 W kg -1 when the incident power density is at the reference level of ICNIRP guideline for general public environment. (note)

  7. Simulation of Heating with the Waves of Ion Cyclotron Range of Frequencies in Experimental Advanced Superconducting Tokamak

    International Nuclear Information System (INIS)

    Yang Cheng; Zhu Sizheng; Zhang Xinjun

    2010-01-01

    Simulation on the heating scenarios in experimental advanced superconducting tokamak (EAST) was performed by using a full wave code TORIC. The locations of resonance layers for these heating schemes are predicted and the simulations for different schemes in ICRF experiments in EAST, for example, ion heating (both fundamental and harmonic frequency) or electron heating (by direct fast waves or by mode conversion waves), on-axis or off-axis heating, and high-field-side (HFS) launching or low-field-side (LFS) launching, etc, were conducted. For the on-axis minority ion heating of 3 He in D( 3 He) plasma, the impacts of both density and temperature on heating were discussed in the EAST parameter ranges.

  8. A wide-frequency range AC magnetometer to measure the specific absorption rate in nanoparticles for magnetic hyperthermia

    International Nuclear Information System (INIS)

    Garaio, E.; Collantes, J.M.; Garcia, J.A.; Plazaola, F.; Mornet, S.; Couillaud, F.; Sandre, O.

    2014-01-01

    Measurement of specific absorption rate (SAR) of magnetic nanoparticles is crucial to assert their potential for magnetic hyperthermia. To perform this task, calorimetric methods are widely used. However, those methods are not very accurate and are difficult to standardize. In this paper, we present AC magnetometry results performed with a lab-made magnetometer that is able to obtain dynamic hysteresis-loops in the AC magnetic field frequency range from 50 kHz to 1 MHz and intensities up to 24 kA m −1 . In this work, SAR values of maghemite nanoparticles dispersed in water are measured by AC magnetometry. The so-obtained values are compared with the SAR measured by calorimetric methods. Both measurements, by calorimetry and magnetometry, are in good agreement. Therefore, the presented AC magnetometer is a suitable way to obtain SAR values of magnetic nanoparticles. - Highlights: • We propose AC magnetometry as a method to measure the specific absorption rate (SAR) of magnetic nanoparticles suitable for magnetic hyperthermia therapy. • We have built a lab-made AC magnetometer, which is able to measure magnetic dynamic hysteresis-loops of nanoparticle dispersions. • The device works with AC magnetic field intensities up to 24 kA m −1 in a frequency range from 75 kHz to 1 MHz. • The SAR values of maghemite nanoparticles around 12 nm in magnetic diameter dispersed in water are measured by the lab-made magnetometer and different calorimetric methods. • Although all methods are in good agreement, several factors (probe location, thermal inertia, losses, etc.) make calorimetric method less accurate than AC magnetometry

  9. The contribution of microbunching instability to solar flare emission in the GHz to THz range of frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Michael Klopf, J. [Department of Applied Science, College of William and Mary, McGlothlin-Street Hall, Williamsburg, VA 23187 (United States); Kaufmann, Pierre; Raulin, Jean-Pierre; Szpigel, Sérgio [Centro de Rádio-Astronomia e Astrofísica Mackenzie, Escola de Engenharia, Universidade Presbiteriana Mackenzie, Rua Consolação 896, São Paulo, SP 01302-907 (Brazil)

    2014-08-10

    Recent solar flare observations in the sub-terahertz range have provided evidence of a new spectral component with fluxes increasing for larger frequencies, separated from the well-known microwave emission that maximizes in the gigahertz range. Suggested interpretations explain the terahertz spectral component but do not account for the simultaneous microwave component. We present a mechanism for producing the observed 'double spectra'. Based on coherent enhancement of synchrotron emission at long wavelengths in laboratory accelerators, we consider how similar processes may occur within a solar flare. The instability known as microbunching arises from perturbations that produce electron beam density modulations, giving rise to broadband coherent synchrotron emission at wavelengths comparable to the characteristic size of the microbunch structure. The spectral intensity of this coherent synchrotron radiation (CSR) can far exceed that of the incoherent synchrotron radiation (ISR), which peaks at a higher frequency, thus producing a double-peaked spectrum. Successful CSR simulations are shown to fit actual burst spectral observations, using typical flaring physical parameters and power-law energy distributions for the accelerated electrons. The simulations consider an energy threshold below which microbunching is not possible because of Coulomb repulsion. Only a small fraction of the radiating charges accelerated to energies above the threshold is required to produce the microwave component observed for several events. The ISR/CSR mechanism can occur together with other emission processes producing the microwave component. It may bring an important contribution to microwaves, at least for certain events where physical conditions for the occurrence of the ISR/CSR microbunching mechanism are possible.

  10. Investigation of electrostatic waves in the ion cyclotron range of frequencies in L-4 and ACT-1

    International Nuclear Information System (INIS)

    Ono, Masayuki.

    1993-05-01

    Electrostatic waves in the ion cyclotron range of frequencies (ICRF) were studied in the Princeton L-4 and ACT-1 devices for approximately ten years, from 1975 to 1985. The investigation began in the L-4 linear device, looking for the parametric excitation of electrostatic ion cyclotron waves in multi-ion-species plasmas. In addition, this investigation verified multi-ion-species effects on the electrostatic ion cyclotron wave dispersion religion including the ion-ion hybrid resonance. Finite-Larmor-radius modification of the wave dispersion relation was also observed, even for ion temperatures of T i ∼ 1/40 eV. Taking advantage of the relatively high field and long device length of L-4, the existence of the cold electrostatic ion cyclotron wave (CES ICW) was verified. With the arrival of the ACT-1 toroidal device, finite-Larmor-radius (FLR) waves were studied in a relatively collisionless warm-ion hydrogen plasma. Detailed investigations of ion Bernstein waves (IBW) included the verification of mode-transformation in their launching, their wave propagation characteristics, their absorption, and the resulting ion heating. This basic physics activity played a crucial role in developing a new reactor heating concept termed ion Bernstein wave heating. Experimental research in the lower hybrid frequency range confirmed the existence of FLR effects near the lower hybrid resonance, predicted by Stix in 1965. In a neon plasma with a carefully placed phased wave exciter, the neutralized ion Bernstein wave was observed for the first time. Using a fastwave ICRF antenna, two parasitic excitation processes for IBW -- parametric instability and density-gradient-driven excitation -- were also discovered. In the concluding section of this paper, a possible application of externally launched electrostatic waves is suggested for helium ash removal from fusion reactor plasmas

  11. A wide range ultra-low power Phase-Locked Loop with automatic frequency setting in 130 nm CMOS technology for data serialisation

    International Nuclear Information System (INIS)

    Firlej, M.; Fiutowski, T.; Idzik, M.; Moroń, J.; Świentek, K.

    2015-01-01

    The design and measurements results of a wide frequency range ultra-low power Phase-Locked Loop (PLL) for applications in readout systems of particle physics detectors are presented. The PLL was fabricated in a 130 nm CMOS technology. To allow the implementation of different data serialisation schemes multiple division factors (6, 8, 10, 16) were implemented in the PLL feedback loop. The main PLL block—VCO works in 16 frequency ranges/modes, switched either manually or automatically. A dedicated automatic frequency mode switching circuit was developed to allow simple frequency tuning. Although the PLL was designed and simulated for a frequency range of 30 MHz–3 GHz, due to the SLVS interface limits, the measurements were done only up to 1.3 GHz. The full PLL functionality was experimentally verified, confirming a very low and frequency scalable power consumption (0.7 mW at 1 GHz)

  12. A wide range ultra-low power Phase-Locked Loop with automatic frequency setting in 130 nm CMOS technology for data serialisation

    Science.gov (United States)

    Firlej, M.; Fiutowski, T.; Idzik, M.; Moroń, J.; Świentek, K.

    2015-12-01

    The design and measurements results of a wide frequency range ultra-low power Phase-Locked Loop (PLL) for applications in readout systems of particle physics detectors are presented. The PLL was fabricated in a 130 nm CMOS technology. To allow the implementation of different data serialisation schemes multiple division factors (6, 8, 10, 16) were implemented in the PLL feedback loop. The main PLL block—VCO works in 16 frequency ranges/modes, switched either manually or automatically. A dedicated automatic frequency mode switching circuit was developed to allow simple frequency tuning. Although the PLL was designed and simulated for a frequency range of 30 MHz-3 GHz, due to the SLVS interface limits, the measurements were done only up to 1.3 GHz. The full PLL functionality was experimentally verified, confirming a very low and frequency scalable power consumption (0.7 mW at 1 GHz).

  13. Observation of vapor pressure enhancement of rare-earth metal-halide salts in the temperature range relevant to metal-halide lamps

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J. J.; Henins, A.; Hardis, J. E. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Estupinan, E. G. [Osram Sylvania Inc., Beverly, Massachusetts 01915 (United States); Lapatovich, W. P. [Independent Consultant, 51 Pye Brook Lane, Boxford, Massachusetts 01921 (United States); Shastri, S. D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2012-02-20

    Total vapor-phase densities of Dy in equilibrium with a DyI{sub 3}/InI condensate and Tm in equilibrium with a TmI{sub 3}/TlI condensate have been measured for temperatures between 900 K and 1400 K. The measurements show strong enhancements in rare-earth vapor densities compared to vapors in equilibrium with the pure rare-earth metal-halides. The measurements were made with x-ray induced fluorescence on the sector 1-ID beam line at the Advanced Photon Source. The temperature range and salt mixtures are relevant to the operation of metal-halide high-intensity discharge lamps.

  14. Natural frequencies, modeshapes and modal interactions for strings vibrating against an obstacle: Relevance to Sitar and Veena

    Science.gov (United States)

    Mandal, A. K.; Wahi, P.

    2015-03-01

    We study the vibration characteristics of a string with a smooth unilateral obstacle placed at one of the ends similar to the strings in musical instruments like sitar and veena. In particular, we explore the correlation between the string vibrations and some unique sound characteristics of these instruments like less inharmonicity in the frequencies, a large number of overtones and the presence of both frequency and amplitude modulations. At the obstacle, we have a moving boundary due to the wrapping of the string and an appropriate scaling of the spatial variable leads to a fixed boundary at the cost of introducing nonlinearity in the governing equation. Reduced order system of equations has been obtained by assuming a functional form for the string displacement which satisfies all the boundary conditions and gives the free length of the string in terms of the modal coordinates. To study the natural frequencies and mode-shapes, the nonlinear governing equation is linearized about the static configuration. The natural frequencies have been found to be harmonic and they depend on the shape of the obstacle through the effective free length of the string. Expressions have been obtained for the time-varying mode-shapes as well as the variation of the nodal points. Modal interactions due to coupling have been studied which show the appearance of higher overtones as well as amplitude modulations in our theoretical model akin to the experimental observations. All the obtained results have been verified with an alternate formulation based on the assumed mode method with polynomial shape functions.

  15. Optically stabilized Erbium fiber frequency comb with hybrid mode-locking and a broad tunable range of repetition rate.

    Science.gov (United States)

    Yang, Honglei; Wu, Xuejian; Zhang, Hongyuan; Zhao, Shijie; Yang, Lijun; Wei, Haoyun; Li, Yan

    2016-12-01

    We present an optically stabilized Erbium fiber frequency comb with a broad repetition rate tuning range based on a hybrid mode-locked oscillator. We lock two comb modes to narrow-linewidth reference lasers in turn to investigate the best performance of control loops. The control bandwidth of fast and slow piezoelectric transducers reaches 70 kHz, while that of pump current modulation with phase-lead compensation is extended to 32 kHz, exceeding laser intrinsic response. Eventually, simultaneous lock of both loops is realized to totally phase-stabilize the comb, which will facilitate precision dual-comb spectroscopy, laser ranging, and timing distribution. In addition, a 1.8-MHz span of the repetition rate is achieved by an automatic optical delay line that is helpful in manufacturing a secondary comb with a similar repetition rate. The oscillator is housed in a homemade temperature-controlled box with an accuracy of ±0.02  K, which not only keeps high signal-to-noise ratio of the beat notes with reference lasers, but also guarantees self-starting at the same mode-locking every time.

  16. Broadband photosensor with a tunable frequency range, built on the basis of nanoscale carbon structure with field localization

    Science.gov (United States)

    Yakunin, Alexander N.; Akchurin, Garif G.; Aban'shin, Nikolay P.; Gorfinkel, Boris I.

    2014-03-01

    The work is devoted to the development of a new direction in creating of broadband photo sensors which distinctive feature is the possibility of dynamic adjustment of operating frequency range. The author's results of study of red threshold control of classic photoelectric effect were the basis for the work implementation. This effect was predicted theoretically and observed experimentally during irradiation of nanoscale carbon structure of planar-edge type by stream of low-energy photons. The variation of the accelerating voltage within a small range allows you to change photoelectric threshold for carbon in a wide range - from UV to IR. This is the consequence of the localization of electrostatic field at tip of the blade planar structure and of changes in the conditions of non-equilibrium electrons tunneling from the boundary surface of the cathode into the vacuum. The generation of nonequilibrium electrons in the carbon film thickness of 20 nm has a high speed which provides high performance of photodetector. The features of the use of nanoscale carbon structure photocurrent registration as in the prethreshold regime, and in the mode of field emission existence are discussed. The results of simulation and experimental examination of photosensor samples are given. It is shown that the observed effect is a single-photon tunneling. This in combination with the possibility of highspeed dynamic tuning determines the good perspectives for creation of new devices working in the mode of select multiple operating spectral bands for the signal recording. The architecture of such devices is expected to be significantly simpler than the conventional ones, based on the use of tunable filters.

  17. Extending the frequency range of free-field reciprocity calibration of measurement microphones to frequencies up to 150 kHz

    DEFF Research Database (Denmark)

    Barrera Figueroa, Salvador; Torras Rosell, Antoni; Jacobsen, Finn

    2013-01-01

    Measurement microphones are typically calibrated in a free field at frequencies up to 50 kHz. This is a sufficiently high frequency for the most sound measurement applications related with noise assessment. However, other applications such as the measurement of noise emitted by ultrasound cleanin...

  18. Stimulus variability and the phonetic relevance hypothesis: effects of variability in speaking style, fundamental frequency, and speaking rate on spoken word identification.

    Science.gov (United States)

    Sommers, Mitchell S; Barcroft, Joe

    2006-04-01

    Three experiments were conducted to examine the effects of trial-to-trial variations in speaking style, fundamental frequency, and speaking rate on identification of spoken words. In addition, the experiments investigated whether any effects of stimulus variability would be modulated by phonetic confusability (i.e., lexical difficulty). In Experiment 1, trial-to-trial variations in speaking style reduced the overall identification performance compared with conditions containing no speaking-style variability. In addition, the effects of variability were greater for phonetically confusable words than for phonetically distinct words. In Experiment 2, variations in fundamental frequency were found to have no significant effects on spoken word identification and did not interact with lexical difficulty. In Experiment 3, two different methods for varying speaking rate were found to have equivalent negative effects on spoken word recognition and similar interactions with lexical difficulty. Overall, the findings are consistent with a phonetic-relevance hypothesis, in which accommodating sources of acoustic-phonetic variability that affect phonetically relevant properties of speech signals can impair spoken word identification. In contrast, variability in parameters of the speech signal that do not affect phonetically relevant properties are not expected to affect overall identification performance. Implications of these findings for the nature and development of lexical representations are discussed.

  19. Physics of the Brain. Prevention of the Epileptic Seizures by the Multi-photon Pulsed-operated Fiber Lasers in the Ultraviolet Range of Frequencies.

    Science.gov (United States)

    Stefan, V. Alexander; IAPS Team

    The novel study of the epileptogenesis mechanisms is proposed. It is based on the pulsed-operated (amplitude modulation) multi-photon (frequency modulation) fiber-laser interaction with the brain epilepsy-topion (the epilepsy onset area), so as to prevent the excessive electrical discharge (epileptic seizure) in the brain. The repetition frequency, Ω, matches the low frequency (epileptic) phonon waves in the brain. The laser repetition frequency (5-100 pulses per second) enables the resonance-scanning of the wide range of the phonon (possible epileptic-to-be) activity in the brain. The tunable fiber laser frequencies, Δω (multi photon operation), are in the ultraviolet frequency range, thus enabling monitoring of the electrical charge imbalance (within the 10s of milliseconds), and the DNA-corruption in the epilepsy-topion, as the possible cause of the disease. Supported by Nikola Tesla Labs., Stefan University.

  20. Increased frequency and range of sexual behavior in a patient with Parkinson's disease after use of pramipexole: a case report.

    Science.gov (United States)

    Munhoz, Renato P; Fabiani, Giorgio; Becker, Nilson; Teive, Hélio A G

    2009-04-01

    Several recent reports have linked the use of dopamine agonists (DAs) to a variety of compulsive behaviors in patients with Parkinson's disease (PD). These inappropriate behaviors may include pathological gambling, compulsive shopping, and hypersexuality. To report the case of a patient with increased range of sexual behavior after use of pramipexole, a DA. A 67-year-old man with a 7-year diagnosis of PD treated with levodopa and pramipexole presented with a dramatic change in sexual behavior after an increase in DA dose. The patient, who historically was a very shy and conservative person, started to present increased frequency of sexual intercourse with his wife, during which he began speaking obscenities with an extreme preference for anal intercourse, preferences never requested before. After pramipexole was withdrawn, complete remission was observed with return to his usual sexual behavior. Hypersexuality and paraphilias are complications not uncommonly found in patients with PD under dopaminergic treatment. Further studies are needed for the understanding of this complex complication, and particularly the most prevalent relationship between pathological hypersexuality and use of DAs.

  1. Main principles of passive devices based on graphene and carbon films in microwave-THz frequency range

    Science.gov (United States)

    Kuzhir, Polina P.; Paddubskaya, Alesia G.; Volynets, Nadezhda I.; Batrakov, Konstantin G.; Kaplas, Tommi; Lamberti, Patrizia; Kotsilkova, Rumiana; Lambin, Philippe

    2017-07-01

    The ability of thin conductive films, including graphene, pyrolytic carbon (PyC), graphitic PyC (GrPyC), graphene with graphitic islands (GrI), glassy carbon (GC), and sandwich structures made of all these materials separated by polymer slabs to absorb electromagnetic radiation in microwave-THz frequency range, is discussed. The main physical principles making a basis for high absorption ability of these heterostructures are explained both in the language of electromagnetic theory and using representation of equivalent electrical circuits. The idea of using carbonaceous thin films as the main working elements of passive radiofrequency (RF) devices, such as shields, filters, polarizers, collimators, is proposed theoretically and proved experimentally. The important advantage of PyC, GrI, GrPyC, and GC is that, in contrast to graphene, they either can be easily deposited onto a dielectric substrate or are strong enough to allow their transfer from the catalytic substrate without a shuttle polymer layer. This opens a new avenue toward the development of a scalable protocol for cost-efficient production of ultralight electromagnetic shields that can be transferred to commercial applications. A robust design via finite-element method and design of experiment for RF devices based on carbon/graphene films and sandwiches is also discussed in the context of virtual prototyping.

  2. Free-ranging male koalas use size-related variation in formant frequencies to assess rival males.

    Directory of Open Access Journals (Sweden)

    Benjamin D Charlton

    Full Text Available Although the use of formant frequencies in nonhuman animal vocal communication systems has received considerable recent interest, only a few studies have examined the importance of these acoustic cues to body size during intra-sexual competition between males. Here we used playback experiments to present free-ranging male koalas with re-synthesised bellow vocalisations in which the formants were shifted to simulate either a large or a small adult male. We found that male looking responses did not differ according to the size variant condition played back. In contrast, male koalas produced longer bellows and spent more time bellowing when they were presented with playbacks simulating larger rivals. In addition, males were significantly slower to respond to this class of playback stimuli than they were to bellows simulating small males. Our results indicate that male koalas invest more effort into their vocal responses when they are presented with bellows that have lower formants indicative of larger rivals, but also show that males are slower to engage in vocal exchanges with larger males that represent more dangerous rivals. By demonstrating that male koalas use formants to assess rivals during the breeding season we have provided evidence that male-male competition constitutes an important selection pressure for broadcasting and attending to size-related formant information in this species. Further empirical studies should investigate the extent to which the use of formants during intra-sexual competition is widespread throughout mammals.

  3. Stochastic reduced-order model for an automotive vehicle in presence of numerous local elastic modes in the low-frequency range

    OpenAIRE

    Arnoux , A.; Batou , Anas; Soize , Christian; Gagliardini , L.

    2012-01-01

    International audience; This paper is devoted to the construction of a stochastic reduced-order model for dynamical structures having a high modal density in the low-frequency range, such as an automotive vehicle. This type of structure is characterized by the fact that it exhibits, in the low-frequency range, not only the classical global elastic modes but also numerous local elastic modes which cannot easily be separated from the global elastic modes. An approach has recently been proposed ...

  4. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation.

    Directory of Open Access Journals (Sweden)

    Katsuya Kobayashi

    Full Text Available Physiological high frequency activities (HFA are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections, or different terminal layers (layer IV vs. layer II/III affect its frequency, we, in the primary somatosensory cortex (SI, compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response and N80 (late response of somatosensory evoked potentials (HFA(SEP(N20 and HFA(SEP(N80 and compared those overriding N1 and N2 (first and second responses of cortico-cortical evoked potentials (HFA(CCEP(N1 and HFA(CCEP(N2. HFA(SEP(N20 showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1 had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1 and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.

  5. One-D full-wave description of plasma emission and absorption in the ion cyclotron range of frequency in tokamaks

    International Nuclear Information System (INIS)

    Fraboulet, D.; Becoulet, A.; Nguyen, F.

    1998-11-01

    To maintain the ignition state in a tokamak fusion reactor, a control must be performed on the population of alpha-products, and this implies the ability to diagnose those α-particles. It is studied here whether the detection of emission radiated in the ion cyclotron range of frequency be a reactor plasma can provide useful information concerning fusion products, especially concerning their density profile. It is shown that the detection of the radiation emitted by the fast alpha particles along their cyclotron motion can give access to moments of their distribution function. This requires to compute the phase of the emitted field, using a full-wave approach. Such a technique allows to set in a convenient way the inverse problem of the determination of the emitting α-particles distribution through the radiation detection. A brief analysis of the expected situation in a reactor-relevant plasma is given. In parallel, the 1-D full-wave code developed in this frame is also useful for studying the physics of Fast Wave plasma heating. It enables to take into account the mode conversion of the Fast Wave into the Ion Bernstein Wave that appears near each ion cyclotron resonance. Results show that higher order terms may significantly alter the energy partitioning, in hot plasma cases involving mode conversion heating and/or ion cyclotron high harmonics heating. (author)

  6. Three-dimensional polarization characteristics of magnetic variations in the Pc 5 frequency range at conjugate areas near L=4

    International Nuclear Information System (INIS)

    Fukunishi, H.; Lanzerotti, L.J.; MaClennan, C.G.

    1975-01-01

    By using magnetic data measured at a network of stations extending from L approx. 3.2 to L approx. 4.4 and at a station in the conjugate area, ellipticities in the three orthogonal planes (H-D, H-Z, and D-Z) for the frequency range 2-5 mHz were computed continuously by the cross-spectral matrix method over 10 days with various levels of magnetic activity. The ellipticity diagrams in the H-D plane show that, except for the time interval during the main phase of a major magnetic storm, the sense of polarization reverses every day across local noon, with a left-hand polarization observed during local morning hours and a right-hand polarization observed during local evening hours, regardless of the level of magnetic activity. The second reversal of the sense of polarization occurs generally around approx. 2000 LT. The ellipticity diagrams in the H-Z plane show a predominantly clockwise polarization throughout the day, while the diurnal variation of the ellipticity in the D-Z plane tends to be confused. As to the latitude dependence of the wave phase, it is found that the D component oscillations are almost in phase at all latitudes, while the H component oscillations have advanced phase shifts at the lower-latitude stations. As to the conjugate dependence of wave phase, it is found that the D component oscillations are almost out of phase, while the H component oscillations are almost in phase atthe conjugate pair stations. These polarization characteristics are discussed in terms of external driving sources coupling to the shear Alfven waves of the local resonant field lines. Possible energy sources of Pc 5 waves are also discussed on the basis of the local time dependence of the sense of polarization

  7. Characterization of the mutual influence of Ion Cyclotron and Lower Hybrid Range of frequencies systems on EAST

    Directory of Open Access Journals (Sweden)

    Urbanczyk Guillaume

    2017-01-01

    Full Text Available Waves in the Ion Cyclotron (ICRF and Lower Hybrid (LH Range of Frequencies are efficient techniques respectively to heat the plasma and drive current. Main difficulties come from a trade-off between good RF coupling and acceptable level of impurities release. The mutual influence of both systems makes such equilibrium often hard to reach [1]. In order to investigate those interactions based on Scrape-Off Layer (SOL plasma parameters, a new reciprocating probe was designed allying a three tips Langmuir probe with an emissive wire. The emissive filament provides a precise measure of plasma potential [2], which can be used to calibrate Langmuir probe's results. This paper reports on experimental results obtained on EAST, where there are two ICRF antennas and two LH launchers. Among others diagnostics, the new reciprocating probe enabled to evidence the deleterious influence of ICRF power on LHWs coupling in L-mode plasmas. In areas connected with an active ICRF antenna, SOL potentials increase while densities tend to decrease, respectively enhancing impurities release and deteriorating LHWs coupling. This phenomenon has mostly been attributed to RF sheath; the one that forms on top of Plasma Facing Components (PFCs and causes ExB density convections [3]. From those experiments it seems ICRF has a strong influence on magnetically connected areas, both in the near field – influencing ICRF waves coupling – and in farther locations such as in front of LH grills. Moreover, influence of ICRF on LH system was observed both in L and H modes. Those results are consistent with RF sheath rectification process. Concerning the influence of LHWs on ICRF coupling, nothing was observed in L-mode. Besides during H-mode experiments, LHWs have been identified as having a mitigating effect on ELMs [4], which on average lowers the pedestal, increasing edge densities to the profit of ICRF waves coupling.

  8. Morphological Parameters in Relation to the Electromagnetic Properties of Microcellular Thermoplastic Polyurethane Foam in X-Band Frequency Ranges

    Directory of Open Access Journals (Sweden)

    Mohammad Hassan Moeini

    2017-04-01

    Full Text Available Microcellular thermoplastic polyurethane foams are examined as absorbing materials in the X-band (8.2-12.4 GHz frequency range by means of experiment. In this work, we aim to establish relationships between foam morphology including cell size and air volume fraction and electromagnetic properties including absorption, transmission and reflection quality. Nanocomposites based on thermoplastic polyurethane containing carbon black were prepared by coagulation method. In this procedure 15 wt% carbon black-containing nanocomposite was converted to microcellular foams using batch foaming process and supercritical carbon dioxide as physical foaming agent. The morphology of the foams was evaluated by scanning electron microscopy. S-parameters of the samples were measured by a vector network analyzer (VNA and the effect of morphological parameters such as cell size and air volume fraction on the absorbing properties was investigated. We also established structure/properties relationships which were essential for further optimizations of the materials used in the construction of radar absorbing composites. Foaming reduced the percolation threshold of the nanocomposites due to the reduction in the average distance between nanoparticles. Foaming and dielectric constant reduction dropped the reflection percentage significantly. The increase in air volume fraction in the foam increased absorption per its weight, because of multiple scattering in composite media. The sensitivity of electromagnetic wave toward the variation of cell size is strongly weaker than that toward the variation of air volume fraction. Electromagnetic properties of the microcellular foams deviated a little from effective medium theories (EMTs. Air volume fraction of the cells was a function of cell size and smaller cells showed higher absorption.

  9. Incidence of milrinone blood levels outside the therapeutic range and their relevance in children after cardiac surgery for congenital heart disease.

    Science.gov (United States)

    Garcia Guerra, Gonzalo; Joffe, Ari R; Senthilselvan, Ambikaipakan; Kutsogiannis, Demetrios J; Parshuram, Christopher S

    2013-05-01

    To evaluate whether variability in milrinone blood levels (MBL) occurs during administration to critically ill children after surgical repair of congenital heart disease, and the clinical relevance of this variability. Prospective cohort study conducted in the pediatric intensive care unit of a tertiary care teaching and referral hospital. MBL were measured at three time periods after starting milrinone infusion (9-12, 18-24, 40-48 h) and at the end of the infusion. MBL were categorized as within (100-300 ng/ml) or outside the therapeutic range. Low cardiac output syndrome was defined by elevation of either lactate (>2 mmol/l) or arteriovenous oxygen difference (>30%). Five other clinical outcomes were evaluated. Regression analyses evaluated the relationships between MBL and outcomes. Sixty-three patients were included with a total of 220 MBL. Quantification of MBL was by high-performance liquid chromatography. Overall, 114 (52%) MBL were outside the therapeutic range: 78 (36%) subtherapeutic, and 36 (16%) supratherapeutic. Repeated-measures analysis found a significant association between supratherapeutic MBL and low cardiac output syndrome (p = 0.02), and supratherapeutic MBL were associated with arterial-central venous oxygen saturation difference >30% at time 3 (p = 0.007). In this cohort, nontherapeutic MBL were common. Further investigation of milrinone dosing recommendations may improve the postoperative outcomes of children.

  10. Face Recognition Is Affected by Similarity in Spatial Frequency Range to a Greater Degree Than Within-Category Object Recognition

    Science.gov (United States)

    Collin, Charles A.; Liu, Chang Hong; Troje, Nikolaus F.; McMullen, Patricia A.; Chaudhuri, Avi

    2004-01-01

    Previous studies have suggested that face identification is more sensitive to variations in spatial frequency content than object recognition, but none have compared how sensitive the 2 processes are to variations in spatial frequency overlap (SFO). The authors tested face and object matching accuracy under varying SFO conditions. Their results…

  11. Efficient frequency downconversion at the single photon level from the red spectral range to the telecommunications C-band.

    Science.gov (United States)

    Zaske, Sebastian; Lenhard, Andreas; Becher, Christoph

    2011-06-20

    We report on single photon frequency downconversion from the red part of the spectrum (738 nm) to the telecommunications C-band. By mixing attenuated laser pulses with an average photon number per pulse telecommunications wavelengths.

  12. Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Moda)

    Science.gov (United States)

    Wukitch, S. J.; Garrett, M. L.; Ochoukov, R.; Terry, J. L.; Hubbard, A.; Labombard, B.; Lau, C.; Lin, Y.; Lipschultz, B.; Miller, D.; Reinke, M. L.; Whyte, D.; Alcator C-Mod Team

    2013-05-01

    Ion cyclotron range of frequency (ICRF) heating is expected to provide auxiliary heating for ITER and future fusion reactors where high Z metallic plasma facing components (PFCs) are being considered. Impurity contamination linked to ICRF antenna operation remains a major challenge particularly for devices with high Z metallic PFCs. Here, we report on an experimental investigation to test whether a field aligned (FA) antenna can reduce impurity contamination and impurity sources. We compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore the underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E|| (electric field along a magnetic field line) via symmetry. A finite element method RF antenna model coupled to a cold plasma model verifies that the integrated E|| should be reduced for all antenna phases. Monopole phasing in particular is expected to have the lowest integrated E||. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20%-30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. However, inconsistent with expectations, we observe RF induced plasma potentials (via gas-puff imaging and emissive probes to be nearly identical for FA and TA antennas when operated in dipole phasing). Moreover, the highest levels of RF-induced plasma potentials are observed using monopole phasing with the FA antenna. Thus, while impurity contamination and sources are indeed

  13. Laser-Bioplasma Interaction: Excitation and Suppression of the Brain Waves by the Multi-photon Pulsed-operated Fiber Lasers in the Ultraviolet Range of Frequencies

    Science.gov (United States)

    Stefan, V. Alexander; IAPS-team Team

    2017-10-01

    The novel study of the laser excitation-suppression of the brain waves is proposed. It is based on the pulsed-operated multi-photon fiber-laser interaction with the brain parvalbumin (PV) neurons. The repetition frequency matches the low frequency brain waves (5-100 Hz); enabling the resonance-scanning of the wide range of the PV neurons (the generators of the brain wave activity). The tunable fiber laser frequencies are in the ultraviolet frequency range, thus enabling the monitoring of the PV neuron-DNA, within the 10s of milliseconds. In medicine, the method can be used as an ``instantaneous-on-off anesthetic.'' Supported by Nikola Tesla Labs, Stefan University.

  14. Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

    International Nuclear Information System (INIS)

    Reinhard, Benjamin; Schmitt, Klemens M.; Neu, Jens; Wollrab, Viktoria; Beigang, Rene; Rahm, Marco

    2012-01-01

    We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16 000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.

  15. Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Reinhard, Benjamin; Schmitt, Klemens M.; Neu, Jens [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Wollrab, Viktoria; Beigang, Rene; Rahm, Marco [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Fraunhofer Institute for Physical Measurement Techniques IPM, 79110 Freiburg (Germany)

    2012-05-28

    We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16 000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.

  16. Simulation of electron transport in GaAs/AlAs superlattices with a small number of periods for the THz frequency range

    International Nuclear Information System (INIS)

    Pavelyev, D. G.; Vasilev, A. P.; Kozlov, V. A.; Koschurinov, Yu. I.; Obolenskaya, E. S.; Obolensky, S. V.; Ustinov, V. M.

    2016-01-01

    The electron transport in superlattices based on GaAs/AlAs heterostructures with a small number of periods (6 periods) is calculated by the Monte Carlo method. These superlattices are used in terahertz diodes for the frequency stabilization of quantum cascade lasers in the range up to 4.7 THz. The band structure of superlattices with different numbers of AlAs monolayers is considered and their current–voltage characteristics are calculated. The calculated current–voltage characteristics are compared with the experimental data. The possibility of the efficient application of these superlattices in the THz frequency range is established both theoretically and experimentally.

  17. Nonlinear optical response of a gold surface in the visible range: A study by two-color sum-frequency generation spectroscopy. I. Experimental determination.

    Science.gov (United States)

    Dalstein, L; Revel, A; Humbert, C; Busson, B

    2018-04-07

    We experimentally determine the effective nonlinear second-order susceptibility of gold over the visible spectral range. To reach that goal, we probe by vibrational two-color sum-frequency generation spectroscopy the methyl stretching region of a dodecanethiol self-assembled monolayer adsorbed on a gold film. The sum-frequency generation spectra show a remarkable shape reversal when the visible probe wavelength is tuned from 435 to 705 nm. After correcting from Fresnel effects, the methyl stretching vibrations serve as an internal reference, allowing to extract the dispersion of the absolute phase and relative amplitude of the effective nonlinear optical response of gold in the visible range.

  18. Dielectric Properties of Marsh Vegetation in a Frequency Range of 0.1-18 GHz Under Variation of Temperature and Moisture

    Science.gov (United States)

    Romanov, A. N.; Kochetkova, T. D.; Suslyaev, V. I.; Shcheglova, A. S.

    2017-09-01

    Dielectric characteristics of some species of marsh vegetation: lichen Cladonia stellaris (Opiz) Pouzar, moss Sphagnum, and a representative of Bryidae mosses - Dicranum polysetum are studied in the frequency range from 100 MHz to 18 GHz. At a frequency of 1.41 GHz, the influence of temperature in the range from -12 to +20°C on the behavior of dielectric characteristics of mosses, lichens, and peat is studied. The dependences of the dielectric characteristics of vegetation on the volumetric wetness are established.

  19. Intrinsic vs. spurious long-range memory in high-frequency records of environmental radioactivity - Critical re-assessment and application to indoor 222Rn concentrations from Coimbra, Portugal

    Science.gov (United States)

    Donner, Reik V.; Potirakis, Stelios M.; Barbosa, Susana M.; Matos, Jose A. O.

    2015-04-01

    The presence or absence of long-range correlations in environmental radioactivity fluctuations has recently attracted considerable interest. Among a multiplicity of practically relevant applications, identifying and disentangling the environmental factors controlling the variable concentrations of the radioactive noble gas Radon is important for estimating its effect on human health and the efficiency of possible measures for reducing the corresponding exposition. In this work, we present a critical re-assessment of a multiplicity of complementary methods that have been previously applied for evaluating the presence of long-range correlations and fractal scaling in environmental Radon variations with a particular focus on the specific properties of the underlying time series. As an illustrative case study, we subsequently re-analyze two high-frequency records of indoor Radon concentrations from Coimbra, Portugal, each of which spans several months of continuous measurements at a high temporal resolution of five minutes. Our results reveal that at the study site, Radon concentrations exhibit complex multi-scale dynamics with qualitatively different properties at different time-scales: (i) essentially white noise in the high-frequency part (up to time-scales of about one hour), (ii) spurious indications of a non-stationary, apparently long-range correlated process (at time scales between hours and one day) arising from marked periodic components probably related to tidal frequencies, and (iii) low-frequency variability indicating a true long-range dependent process, which might be dominated by a response to meteorological drivers. In the presence of such multi-scale variability, common estimators of long-range memory in time series are necessarily prone to fail if applied to the raw data without previous separation of time-scales with qualitatively different dynamics. We emphasize that similar properties can be found in other types of geophysical time series (for

  20. An all metal array of antennae for RF heating of TOKAMAKS in the ion cyclotron range of frequency

    International Nuclear Information System (INIS)

    Jacquinot, J.; Lebot, H.; Adam, J.; Kuus, H.

    1980-09-01

    500 KW, the maximum available RF power, at a frequency of 60 MHz and in 50 to 100 ms pulses, has been launched in TFR plasmas using an array of 4 half turn antennae. The array has a potential power capability of 1 MW through a single port. The electrical coupling efficiency is about 90%

  1. Simulation of beam-splitter made of metamaterials with angle spatial distribution of constitutive parameters based on transformation optics for THz frequency range

    International Nuclear Information System (INIS)

    Gurvitz, E A; Vozianova, A V; Khodzitsky, M K

    2014-01-01

    New approach to design beam splitter on basis of the transformation optics using angle constitutive parameters distribution of medium was proposed. The beam splitter was numerically simulated by COMSOL Multiphysics for terahertz frequency range. The numerical simulations were carried out for ideal and reduced constitutive parameters of medium for the case of TM plane wave

  2. On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1–20 GHz

    International Nuclear Information System (INIS)

    Fannin, P.C.; Vekas, L.; Marin, C.N.; Malaescu, I.

    2017-01-01

    Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ′(ω, Η)−iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1–20 GHz and polarising fields 0–168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4–6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz. - Highlights: • Complex magnetic susceptibility measurements in the frequency range 0.1–20 GHz. • Determination of the dynamic properties of a transformer oil based ferrofluid. • Wideband attenuator ( Absorber) in the frequency range 2.4–6.3 GHz.

  3. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    Science.gov (United States)

    Drakakis, E.; Kymakis, E.; Tzagkarakis, G.; Louloudakis, D.; Katharakis, M.; Kenanakis, G.; Suchea, M.; Tudose, V.; Koudoumas, E.

    2017-03-01

    We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4-20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  4. Transition to the improved confinement mode in torsatron U-3M in range of rare collision frequencies

    International Nuclear Information System (INIS)

    Pashnev, V.K.; Sorokovov, E.L.; Berezhnyj, V.L. and others

    2010-01-01

    Transition to the mode of improved plasma confinement in U-3M facility earlier was discussed in works [1-3]. In these studies discussed the various processes in the confinement volume and in the peripheral plasma that accompany the transition process. Study of plasma confinement and process of transition into the mode of improved confinement just at rare collisions between plasma particles is very important because future fusion reactor based on a toroidal magnetic trap will operate under plasma parameters with rare collision frequencies ('banana' mode). The peculiarity of experiments on torsatron U-3M is that they are conducted at small density n-bar e ≤ 2 lover case x 10 12 cm -3 and, thereby, the frequency of collisions in the confinement area is in the 'banana' mode [4]. And herewith, time of collisions is essentially smaller (up to several orders for electrons and up to the order for ions) than the lifetime of plasma particles. It ensures maxwellization of distribution function and possibility to compare the obtained results with data from other experiments. The objective of this work is to study the main regularity of transition into the mode of improved confinement. Also it is interesting to compare the results with data from other facilities.

  5. Modelling of plasma-antenna coupling and non-linear radio frequency wave-plasma-wall interactions in the magnetized plasma device under ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Lu, LingFeng

    2016-01-01

    Ion Cyclotron Resonant Heating (ICRH) by waves in 30-80 MHz range is currently used in magnetic fusion plasmas. Excited by phased arrays of current straps at the plasma periphery, these waves exist under two polarizations. The Fast Wave tunnels through the tenuous plasma edge and propagates to its center where it is absorbed. The parasitically emitted Slow Wave only exists close to the launchers. How much power can be coupled to the center with 1 A current on the straps? How do the emitted radiofrequency (RF) near and far fields interact parasitically with the edge plasma via RF sheath rectification at plasma-wall interfaces? To address these two issues simultaneously, in realistic geometry over the size of ICRH antennas, this thesis upgraded and tested the Self-consistent Sheaths and Waves for ICH (SSWICH) code. SSWICH couples self-consistently RF wave propagation and Direct Current (DC) plasma biasing via non-linear RF and DC sheath boundary conditions (SBCs) at plasma/wall interfaces. Its upgrade is full wave and was implemented in two dimensions (toroidal/radial). New SBCs coupling the two polarizations were derived and implemented along shaped walls tilted with respect to the confinement magnetic field. Using this new tool in the absence of SBCs, we studied the impact of a density decaying continuously inside the antenna box and across the Lower Hybrid (LH) resonance. Up to the memory limits of our workstation, the RF fields below the LH resonance changed with the grid size. However the coupled power spectrum hardly evolved and was only weakly affected by the density inside the box. In presence of SBCs, SSWICH-FW simulations have identified the role of the fast wave on RF sheath excitation and reproduced some key experimental observations. SSWICH-FW was finally adapted to conduct the first electromagnetic and RF-sheath 2D simulations of the cylindrical magnetized plasma device ALINE. (author) [fr

  6. Intrinsic vs. spurious long-range memory in high-frequency records of environmental radioactivity. Critical re-assessment and application to indoor 222Rn concentrations from Coimbra, Portugal

    Science.gov (United States)

    Donner, R. V.; Potirakis, S. M.; Barbosa, S. M.; Matos, J. A. O.; Pereira, A. J. S. C.; Neves, L. J. P. F.

    2015-05-01

    The presence or absence of long-range correlations in the environmental radioactivity fluctuations has recently attracted considerable interest. Among a multiplicity of practically relevant applications, identifying and disentangling the environmental factors controlling the variable concentrations of the radioactive noble gas radon is important for estimating its effect on human health and the efficiency of possible measures for reducing the corresponding exposition. In this work, we present a critical re-assessment of a multiplicity of complementary methods that have been previously applied for evaluating the presence of long-range correlations and fractal scaling in environmental radon variations with a particular focus on the specific properties of the underlying time series. As an illustrative case study, we subsequently re-analyze two high-frequency records of indoor radon concentrations from Coimbra, Portugal, each of which spans several weeks of continuous measurements at a high temporal resolution of five minutes.Our results reveal that at the study site, radon concentrations exhibit complex multi-scale dynamics with qualitatively different properties at different time-scales: (i) essentially white noise in the high-frequency part (up to time-scales of about one hour), (ii) spurious indications of a non-stationary, apparently long-range correlated process (at time scales between some hours and one day) arising from marked periodic components, and (iii) low-frequency variability indicating a true long-range dependent process. In the presence of such multi-scale variability, common estimators of long-range memory in time series are prone to fail if applied to the raw data without previous separation of time-scales with qualitatively different dynamics.

  7. Two discharge modes of a repetitive nanosecond pulsed helium glow discharge under sub-atmospheric pressure in the repetition frequency range of 20 to 600 kHz

    Science.gov (United States)

    Kikuchi, Yusuke; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

    2018-05-01

    Two discharge modes, α and γ, of a repetitive nanosecond pulsed helium glow discharge at a gas pressure of 10 kPa in the repetition frequency range from 20 to 600 kHz are reported for the first time. The pulsed glow discharge is produced in a pair of parallel plate metal electrodes without insertion of dielectrics. The α mode discharge is volumetrically produced in the electrode gap at a low-repetition frequency, whereas the γ mode discharge is localized at the cathode surface at a high-repetition frequency. At high-repetition frequency, the time interval between voltage pulses is shorter than the lifetime of the afterglow produced by the preceding discharge. Then, the γ mode discharge is maintained by a large number of secondary electrons emitted from the cathode exposed to high-density ions and metastable helium atoms in the afterglow. In the α mode discharge with a low-repetition frequency operation, primary electrons due to gas ionization dominate the ionization process. Thus, a large discharge voltage is needed for the excitation of the α mode discharge. It is established that the bifurcation of α-γ discharge mode, accompanied by a decrease in the discharge voltage, occurs at the high-repetition frequency of ∼120 kHz.

  8. Coherent MUSIC technique for range/angle information retrieval: Application to a frequency modulated continuous wave MIMO radar

    NARCIS (Netherlands)

    Belfiori, F.; Rossum, W. van; Hoogeboom, P.

    2014-01-01

    A coherent two-dimensional (2D) multiple signal classification (MUSIC) processing for the simultaneous estimation of angular and range target positions has been presented. A 2D spatial smoothing technique is also introduced to cope with the coherent behaviour of the received echoes, which may result

  9. Use of radar QPE for the derivation of Intensity-Duration-Frequency curves in a range of climatic regimes

    Science.gov (United States)

    Marra, Francesco; Morin, Efrat

    2015-12-01

    Intensity-Duration-Frequency (IDF) curves are widely used in flood risk management because they provide an easy link between the characteristics of a rainfall event and the probability of its occurrence. Weather radars provide distributed rainfall estimates with high spatial and temporal resolutions and overcome the scarce representativeness of point-based rainfall for regions characterized by large gradients in rainfall climatology. This work explores the use of radar quantitative precipitation estimation (QPE) for the identification of IDF curves over a region with steep climatic transitions (Israel) using a unique radar data record (23 yr) and combined physical and empirical adjustment of the radar data. IDF relationships were derived by fitting a generalized extreme value distribution to the annual maximum series for durations of 20 min, 1 h and 4 h. Arid, semi-arid and Mediterranean climates were explored using 14 study cases. IDF curves derived from the study rain gauges were compared to those derived from radar and from nearby rain gauges characterized by similar climatology, taking into account the uncertainty linked with the fitting technique. Radar annual maxima and IDF curves were generally overestimated but in 70% of the cases (60% for a 100 yr return period), they lay within the rain gauge IDF confidence intervals. Overestimation tended to increase with return period, and this effect was enhanced in arid climates. This was mainly associated with radar estimation uncertainty, even if other effects, such as rain gauge temporal resolution, cannot be neglected. Climatological classification remained meaningful for the analysis of rainfall extremes and radar was able to discern climatology from rainfall frequency analysis.

  10. Edge measurements during ICRF [ion cyclotron range of frequency] heating on the PLT [Princeton Large Torus] tokamak

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Colestock, P.L.; McNeill, D.H.; Greene, G.J.; Bernabei, S.; Hosea, J.C.; Ono, M.; Shohet, J.L.; Wilson, J.R.

    1989-04-01

    Edge measurements have been conducted on the PLT tokamak under a variety of operating conditions in order to ascertain the relevant processes at work in coupling rf power to plasmas. The edge density is found to increase significantly with the application of ICRF, and electron heating occurs in the vicinity of the Faraday shield surrounding the antenna. Spectroscopic measurements indicate that the energized antenna is a significant particle source. The relative increase of metallic impurities was found to be /approximately/2.7 times larger than the corresponding increase in deuterium. In addition, the relative increase of deuterium and impurities was /approximately/3--4 times greater at the energized antenna than at other locations around the torus. Model calculations show that for deuterium released from the Faraday shield, the D/sub α/ emission is localized radially to a region within 4 cm of the antenna. A correlation was found between the edge density and the D/sub α/ intensity that justifies its use as a measure of the particle source rate. 26 refs., 14 figs

  11. Dielectric spectroscopy in aqueous solutions of paracetamol over the frequency range of 20 Hz to 2 MHz at 293.15 K temperature

    Science.gov (United States)

    Pandit, T. R.; Rana, V. A.

    2018-05-01

    Frequency domain dielectric relaxation spectroscopy plays an important role in the study of pharmaceutical drug molecules. The complex relative dielectric permittivity ɛ*(ω) = ɛ' - j ɛ" of aqueous solutions of paracetamol in the frequency range of 20 Hz to 2 MHz at a temperature range of 293.15 K are measured with the help of Agilent precision LCR meter E4980A along with four terminal liquid test fixture Agilent 16452A. Data of complex relative permittivity are used to calculate loss tangent for all concentrations of paracetamol in distilled water. Electrode polarization relaxation time has been calculated for all solutions. Effect of variation of concentrations of paracetamol in distilled water on these dielectric parameters is discussed.

  12. Sound propagation in water containing large tethered spherical encapsulated gas bubbles with resonance frequencies in the 50 Hz to 100 Hz range.

    Science.gov (United States)

    Lee, Kevin M; Hinojosa, Kevin T; Wochner, Mark S; Argo, Theodore F; Wilson, Preston S; Mercier, Richard S

    2011-11-01

    The efficacy of large tethered encapsulated gas bubbles for the mitigation of low frequency underwater noise was investigated with an acoustic resonator technique. Tethered latex balloons were used as the bubbles, which had radii of approximately 5 cm. Phase speeds were inferred from the resonances of a water and balloon-filled waveguide approximately 1.8 m in length. The Commander and Prosperetti effective-medium model [J. Acoust. Soc. Am. 85, 732-746 (1989)] quantitatively described the observed dispersion from well below to just below the individual bubble resonance frequency, and it qualitatively predicted the frequency range of high attenuation for void fractions between 2% and 5% for collections of stationary balloons within the waveguide. A finite-element model was used to investigate the sensitivity of the waveguide resonance frequencies, and hence the inferred phase speeds, to changes in individual bubble size and position. The results indicate that large tethered encapsulated bubbles could be used mitigate low frequency underwater noise and that the Commander and Prosperetti model would be useful in the design of such a system.

  13. Acute effects on metabolism and appetite profile of one meal difference in the lower range of meal frequency.

    Science.gov (United States)

    Smeets, Astrid J; Westerterp-Plantenga, Margriet S

    2008-06-01

    A gorging pattern of food intake has been shown to enhance lipogenesis and increase body weight, which may be due to large fluctuations in storage and mobilisation of nutrients. In a state of energy balance, increasing meal frequency, and thereby decreasing inter-meal interval, may prevent large metabolic fluctuations. Our aim was to study the effect of the inter-meal interval by dividing energy intake over two or three meals on energy expenditure, substrate oxidation and 24 h satiety, in healthy, normal-weight women in a state of energy balance. The study was a randomised crossover design with two experimental conditions. During the two experimental conditions subjects (fourteen normal-weight women, aged 24.4 (SD 7.1) years, underwent 36 h sessions in energy balance in a respiration chamber for measurements of energy expenditure and substrate oxidation. The subjects were given two (breakfast, dinner) or three (breakfast, lunch, dinner) meals per d. We chose to omit lunch in the two meals condition, because this resulted in a marked difference in inter-meal-interval after breakfast (8.5 h v. 4 h). Eating three meals compared with two meals had no effects on 24 h energy expenditure, diet-induced thermogenesis, activity-induced energy expenditure and sleeping metabolic rate. Eating three meals compared with two meals increased 24 h fat oxidation, but decreased the amount of fat oxidised from the breakfast. The same amount of energy divided over three meals compared with over two meals increased satiety feelings over 24 h. In healthy, normal-weight women, decreasing the inter-meal interval sustains satiety, particularly during the day, and sustains fat oxidation, particularly during the night.

  14. Study of blood plasma optical properties in mice grafted with Ehrlich carcinoma in the frequency range 0.1-1.0 THz

    Science.gov (United States)

    Smolyanskaya, O. A.; Kravtsenyuk, O. V.; Panchenko, A. V.; Odlyanitskiy, E. L.; Guillet, J. P.; Cherkasova, O. P.; Khodzitsky, M. K.

    2017-12-01

    In the course of in vitro studies of blood of laboratory animals with progressing Ehrlich carcinoma, we have revealed the change of the blood plasma optical properties in the THz range, which can be used for developing the express diagnostics of the presence of oncological diseases. An applied software package is elaborated that allows the phantoms of biological samples having a complex structure to be numerically simulated and the parameters of the electromagnetic wave reflected from these samples in the THz frequency range to be calculated. Presented at the Fundamentals of Laser Micro- and Nanotechnologies (FLAMN-16) International Symposium (Pushkin, Leningrad oblast, 27 June to 1 July 2016).

  15. Range-separated time-dependent density-functional theory with a frequency-dependent second-order Bethe-Salpeter correlation kernel

    Energy Technology Data Exchange (ETDEWEB)

    Rebolini, Elisa, E-mail: elisa.rebolini@kjemi.uio.no; Toulouse, Julien, E-mail: julien.toulouse@upmc.fr [Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC Univ Paris 06, CNRS, 4 place Jussieu, F-75005 Paris (France)

    2016-03-07

    We present a range-separated linear-response time-dependent density-functional theory (TDDFT) which combines a density-functional approximation for the short-range response kernel and a frequency-dependent second-order Bethe-Salpeter approximation for the long-range response kernel. This approach goes beyond the adiabatic approximation usually used in linear-response TDDFT and aims at improving the accuracy of calculations of electronic excitation energies of molecular systems. A detailed derivation of the frequency-dependent second-order Bethe-Salpeter correlation kernel is given using many-body Green-function theory. Preliminary tests of this range-separated TDDFT method are presented for the calculation of excitation energies of the He and Be atoms and small molecules (H{sub 2}, N{sub 2}, CO{sub 2}, H{sub 2}CO, and C{sub 2}H{sub 4}). The results suggest that the addition of the long-range second-order Bethe-Salpeter correlation kernel overall slightly improves the excitation energies.

  16. Surface impedance of BaFe2-xNixAs2 in the radio frequency range

    Directory of Open Access Journals (Sweden)

    A. Abbassi

    2012-08-01

    Full Text Available We report measurements of the temperature dependence of the surface impedance in superconducting BaFe1.93Ni0.07As2 crystals using the radiofrequency reflection technique in the 5range. An LC resonant circuit with a phase sensitive detection was used at 92MHz. A measurement assembly with point contacts was used at 30MHz. The recent discovery of iron based arsenide superconductors BaFe2-xNixAs2 has attracted much interest. For a Ni doping level of 7% the superconducting phase transition is found around 20K. The temperature dependence of the superconducting penetration depth was determined.

  17. Calibration of tri-axial MEMS accelerometers in the low-frequency range – Part 2: Uncertainty assessment

    Directory of Open Access Journals (Sweden)

    G. D'Emilia

    2018-05-01

    Full Text Available A comparison among three methods for the calibration of tri-axial accelerometers, in particular MEMS, is presented in this paper, paying attention to the uncertainty assessment of each method. The first method is performed according to the ISO 16063 standards. Two innovative methods are analysed, both suitable for in-field application. The effects on the whole uncertainty of the following aspects have been evaluated: the test bench performances in realizing the reference motion, the vibration reference sensor, the geometrical parameters and the data processing techniques. The uncertainty contributions due to the offset and the transverse sensitivity are also studied, by calibrating two different types of accelerometers, a piezoelectric one and a capacitive one, to check their effect on the accuracy of the methods under comparison. The reproducibility of methods is demonstrated. Relative uncertainty of methods ranges from 3 to 5 %, depending on the complexity of the model and of the requested operations. The results appear promising for low-cost calibration of new tri-axial accelerometers of MEMS type.

  18. A study on the heating and diagnostic of a tokamak plasma by electromagnetic waves of the electron cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Hoshino, Katsumichi

    1989-09-01

    A study on the heating and diagnosis of tokamak plasma by electromagnetic waves of electron cyclotron range of frequency is summarized. The main results obtained are as follows. On the engineering and technology, the technology of injecting high frequency, large power millimeter waves into tokamak plasma was established by carrying out the design, manufacture and test of a 60 GHz, 400 kW high frequency heating system, and the design, manufacture and test of a heterodyne type electron cyclotron radiation multi-channel mealsuring system were carried out, and the technology of measuring the radiation from tokamak plasma with the time resolution of 10 μs in multi-channel was established. On nuclear fusion reactor core engineering and plasma physics, the high efficiency electron heating of tokamak plasma by the incidence of fundamental irregular and regular waves at electron cyclotron frequency was verified. The discovery and analysis of the heating by electrostatic waves arising due to mode transformation from electromagnetic waves in upper hybrid resonance layer were carried out. By the incidence of second harmonic waves, the high efficiency electron heating of tokamak plasma was verified, and the heating characteristics were clarified. And others. (K.I.) 179 refs

  19. Modulation of electromagnetic and absorption properties in 18-26.5 GHz frequency range of strontium hexaferrites with doping of cobalt-zirconium

    Science.gov (United States)

    Pubby, Kunal; Narang, Sukhleen Bindra; Kaur, Prabhjyot; Chawla, S. K.

    2017-05-01

    Hexaferrite nano-particles of stoichiometric composition {{Sr}}{({{CoZr}})_x}{{F}}{{{e}}_{12 - 2x}}{{{O}}_{19}}, with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared using sol-gel auto-combustion route owing to its advantages such as low sintering temperature requirement, homogeneity and uniformity of grains. Tartaric acid as a fuel was utilized to complete the chemical reaction. The goal of this study is to analyse the effect of co-substitution of cobalt and zirconium on the electromagnetic and absorption properties of pure {{SrF}}{{{e}}_{12}}{{{O}}_{19}} hexaferrite. The properties were measured on the rectangular pellets of thickness 2.5 mm for K-frequency band using Vector Network Analyzer. The doping of Co-Zr has resulted in increase in real as well as imaginary parts of permittivity. The values of real permittivity lie in the range 3.6-7.0 for all the composition. The real part of permeability remains in range 0.7-1.6 in the studied frequency band for all the samples and shows slightly increasing trend with frequency. The maximum values of dielectric loss tangent peak (3.04) and magnetic loss tangent peak (2.34), among all the prepared compositions, have been observed for composition x = 0.2. Compositions with x = 0.6 and x = 0.0 also have high dielectric and magnetic loss peaks. Dielectric loss peaks are attributed to dielectric resonance and magnetic loss peaks are attributed to natural resonance. Experimentally determined reflection loss results show that all six compositions of prepared series have high values of absorption to propose them as single-layer absorbers in 18-26.5 GHz frequency range. The composition with x = 0.2 has maximum absorption capacity with reflection loss peak of -37.2 dB at 24.3 GHz frequency. The undoped composition also has high absorption peak (-25.46 dB), but -10 dB absorption bandwidth is minimum (2.2 GHz) out of the present series. Maximum absorption bandwidth is obtained for x = 1.0 (4.1 GHz). Other doped compositions also

  20. Modulation of electromagnetic and absorption properties in 18-26.5 GHz frequency range of strontium hexaferrites with doping of cobalt-zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Pubby, Kunal; Narang, Sukhleen Bindra [Guru Nanak Dev University, Department of Electronics Technology, Amritsar (India); Kaur, Prabhjyot; Chawla, S.K. [Guru Nanak Dev University, Department of Chemistry, Centre for Advanced Studies-I, Amritsar (India)

    2017-05-15

    Hexaferrite nano-particles of stoichiometric composition Sr(CoZr){sub x}Fe{sub 12-2x}O{sub 19}, with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared using sol-gel auto-combustion route owing to its advantages such as low sintering temperature requirement, homogeneity and uniformity of grains. Tartaric acid as a fuel was utilized to complete the chemical reaction. The goal of this study is to analyse the effect of co-substitution of cobalt and zirconium on the electromagnetic and absorption properties of pure SrFe{sub 12}O{sub 19} hexaferrite. The properties were measured on the rectangular pellets of thickness 2.5 mm for K-frequency band using Vector Network Analyzer. The doping of Co-Zr has resulted in increase in real as well as imaginary parts of permittivity. The values of real permittivity lie in the range 3.6-7.0 for all the composition. The real part of permeability remains in range 0.7-1.6 in the studied frequency band for all the samples and shows slightly increasing trend with frequency. The maximum values of dielectric loss tangent peak (3.04) and magnetic loss tangent peak (2.34), among all the prepared compositions, have been observed for composition x = 0.2. Compositions with x = 0.6 and x = 0.0 also have high dielectric and magnetic loss peaks. Dielectric loss peaks are attributed to dielectric resonance and magnetic loss peaks are attributed to natural resonance. Experimentally determined reflection loss results show that all six compositions of prepared series have high values of absorption to propose them as single-layer absorbers in 18-26.5 GHz frequency range. The composition with x = 0.2 has maximum absorption capacity with reflection loss peak of -37.2 dB at 24.3 GHz frequency. The undoped composition also has high absorption peak (-25.46 dB), but -10 dB absorption bandwidth is minimum (2.2 GHz) out of the present series. Maximum absorption bandwidth is obtained for x = 1.0 (4.1 GHz). Other doped compositions also have high absorption bandwidth

  1. Power and efficiency scaling of diode pumped Cr:LiSAF lasers: 770-1110 nm tuning range and frequency doubling to 387-463 nm.

    Science.gov (United States)

    Demirbas, Umit; Baali, Ilyes

    2015-10-15

    We report significant average power and efficiency scaling of diode-pumped Cr:LiSAF lasers in continuous-wave (cw), cw frequency-doubled, and mode-locked regimes. Four single-emitter broad-area laser diodes around 660 nm were used as the pump source, which provided a total pump power of 7.2 W. To minimize thermal effects, a 20 mm long Cr:LiSAF sample with a relatively low Cr-concentration (0.8%) was used as the gain medium. In cw laser experiments, 2.4 W of output power, a slope efficiency of 50%, and a tuning range covering the 770-1110 nm region were achieved. Intracavity frequency doubling with beta-barium borate (BBO) crystals generated up to 1160 mW of blue power and a record tuning range in the 387-463 nm region. When mode locked with a saturable absorber mirror, the laser produced 195 fs pulses with 580 mW of average power around 820 nm at a 100.3 MHz repetition rate. The optical-to-optical conversion efficiency of the system was 33% in cw, 16% in cw frequency-doubled, and 8% in cw mode-locked regimes.

  2. Myxobacteria Are Able to Prey Broadly upon Clinically-Relevant Pathogens, Exhibiting a Prey Range Which Cannot Be Explained by Phylogeny

    Directory of Open Access Journals (Sweden)

    Paul G. Livingstone

    2017-08-01

    Full Text Available Myxobacteria are natural predators of microorganisms and the subjects of concerted efforts to identify novel antimicrobial compounds. Myxobacterial predatory activity seems to require more than just the possession of specific antimicrobial metabolites. Thus a holistic approach to studying predation promises novel insights into antimicrobial action. Here, we report the isolation of 113 myxobacteria from samples of soil taken from a range of habitats in mid Wales. Predatory activity of each isolate was quantified against a panel of clinically important prey organisms, including Klebsiella pneumoniae, Proteus mirabilis, Candida albicans, Enterococcus faecalis, and three species of Staphylococcus. Myxobacterial isolates exhibited a wide range of predation activity profiles against the panel of prey. Efficient predation of all prey by isolates within the collection was observed, with K. pneumoniae and C. albicans proving particularly susceptible to myxobacterial predation. Notably efficient predators tended to be proficient at predating multiple prey organisms, suggesting they possess gene(s encoding a broad range killing activity. However, predatory activity was not congruent with phylogeny, suggesting prey range is subject to relatively rapid specialization, potentially involving lateral gene transfer. The broad but patchy prey ranges observed for natural myxobacterial isolates also implies multiple (potentially overlapping genetic determinants are responsible for dictating predatory activity.

  3. Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations

    International Nuclear Information System (INIS)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2012-01-01

    Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves or ion Bernstein waves at the two-ion hybrid resonances. Mode converted waves are of interest as actuators to optimise plasma performance through current drive and flow drive. In order to describe these processes accurately in a realistic tokamak geometry, numerical simulations are essential, and it is important that these codes be validated against experiment. In this study, the mode converted waves were measured using a phase contrast imaging technique in D-H and D- 3 He plasmas. The measured mode converted wave intensity in the D- 3 He mode conversion regime was found to be a factor of ∼50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  4. On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1-20 GHz

    Science.gov (United States)

    Fannin, P. C.; Vekas, L.; Marin, C. N.; Malaescu, I.

    2017-02-01

    Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ‧(ω, Η)-iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1-20 GHz and polarising fields 0-168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4-6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz.

  5. Photonic filtering of microwave signals in the frequency range of 0.01-20 GHz using a Fabry-Perot filter

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo-Rodriguez, G; Zaldivar-Huerta, I E [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE). Sta. Maria Tonantzintla, Pue. Mexico (Mexico); GarcIa-Juarez, A [Depto. de Investigacion en Fisica, Universidad de Sonora (UNISON) Hermosillo, Son. Mexico (Mexico); Rodriguez-Asomoza, J [Depto. de Ingenieria Electronica, Universidad de las Americas-Puebla (UDLA). San Andres Cholula, Pue. Mexico (Mexico); Larger, L; Courjal, N [Laboratoire d' Optique P. M. Duffieux, UMR 6603 CNRS, Institut des Microtechiques de Franche-Comte, FRW 0067, UFR Sciences et Techniques, Universite de Franche-Comte (UFC), Besancon cedex (France)

    2011-01-01

    We demonstrate experimentally the efficiency of tuning of a photonic filter in the frequency range of 0.01 to 20 GHz. The presented work combines the use of a multimode optical source associated with a dispersive optical fiber to obtain the filtering effect. Tunability effect is achieved by the use of a Fabry-Perot filter that allows altering the spectral characteristics of the optical source. Experimental results are validated by means of numerical simulations. The scheme here proposed has a potential application in the field of optical telecommunications.

  6. Dipole, quadrupole, and octupole terms in the long-range hyperfine frequency shift for hydrogen in the presence of inert gases

    International Nuclear Information System (INIS)

    Greenwood, W.G.; Tang, K.T.

    1987-01-01

    The R -6 , R -8 , and R -10 terms in the long-range expansion for the hyperfine frequency shift are calculated for hydrogen in the presence of He, Ne, Ar, Kr, and Xe. The R -6 terms are based on the dipole oscillator strength sums. For helium, the R -8 and R -10 terms are based on quadrupole and octupole oscillator strength sums. For the heavier inert gases, the results for the R -8 and R -10 terms are obtained from the sum rules and the static polarizabilities. Upper bounds are also determined for the R -8 and R -10 terms

  7. Optimized 3-D electromagnetic models of composite materials in microwave frequency range: application to EMC characterization of complex media by statistical means

    Directory of Open Access Journals (Sweden)

    S. Lalléchère

    2017-05-01

    Full Text Available The aim of this proposal is to demonstrate the ability of tridimensional (3-D electromagnetic modeling tool for the characterization of composite materials in microwave frequency band range. Indeed, an automated procedure is proposed to generate random materials, proceed to 3-D simulations, and compute shielding effectiveness (SE statistics with finite integration technique. In this context, 3-D electromagnetic models rely on random locations of conductive inclusions; results are compared with classical electromagnetic mixing theory (EMT approaches (e.g. Maxwell-Garnett formalism, and dynamic homogenization model (DHM. The article aims to demonstrate the interest of the proposed approach in various domains such as propagation and electromagnetic compatibility (EMC.

  8. Application range affected by software failures in safety relevant instrumentation and control systems of nuclear power plants; Auswirkungsbereiche von Softwarefehlern in sicherheitstechnisch wichtigen Einrichtungen von Kernkraftwerken

    Energy Technology Data Exchange (ETDEWEB)

    Jopen, Manuela; Mbonjo, Herve; Sommer, Dagmar; Ulrich, Birte

    2017-03-15

    This report presents results that have been developed within a BMUB-funded research project (Promotion Code 3614R01304). The overall objective of this project was to broaden the knowledge base of GRS regarding software failures and their impact in software-based instrumentation and control (I and C) systems. To this end, relevant definitions and terms in standards and publications (DIN, IEEE standards, IAEA standards, NUREG publications) as well as in the German safety requirements for nuclear power plants were analyzed first. In particular, it was found that the term ''software fault'' is defined differently and partly contradictory in the considered literature sources. For this reason, a definition of software fault was developed on the basis of the software life cycle of software-based I and C systems within the framework of this project, which takes into account the various aspects relevant to software faults and their related effects. It turns out that software failures result from latent faults in a software-based control system, which can lead to a non-compliant behavior of a software-based I and C system. Hereby a distinction should be made between programming faults and specification faults. In a further step, operational experience with software failures in software-based I and C systems in nuclear facilities and in nonnuclear sector was investigated. The identified events were analyzed with regard to their cause and impacts and the analysis results were summarized. Based on the developed definition of software failure and on the COMPSIS-classification scheme for events related to software based I and C systems, the COCS-classification scheme was developed to classify events from operating experience with software failures, in which the events are classified according to the criteria ''cause'', ''affected system'', ''impact'' and ''CCF potential''. This

  9. Trophodynamics of inorganic pollutants in a wide-range feeder: The relevance of dietary inputs and biomagnification in the Yellow-legged gull (Larus michahellis)

    International Nuclear Information System (INIS)

    Ramos, Raül; Ramírez, Francisco; Jover, Lluís

    2013-01-01

    The suitability of sentinel species to monitor environmental pollution is often hampered by an insufficient knowledge on pollutant trophodynamics. We simultaneously evaluated the influence of individuals' trophic position (as revealed by δ 15 N values) and dietary exploitation of particular systems (using δ 13 C and δ 34 S as proxies) on inorganic pollutant concentrations measured on fledglings' feathers of a wide-range feeder, the Yellow-legged Gull (Larus michahellis), sampled at four locations throughout the Western Mediterranean. Concentrations of total Hg and Se in fledgling feathers (2.43 ± 1.30 and 1.16 ± 0.43 μg/g, respectively) were under the threshold points for deleterious effects on seabirds. On the contrary, alarming Pb concentrations were found in one colony (mean: 1.57 ± 2.46 μg/g, range: 0.16–12.13). With the exception of Pb, pollutant concentrations were positively influenced by consumption of marine resources (as suggested by the positive relationship with δ 34 S values), whereas trophic position played a minor role in determining pollutant body burdens. - Graphical abstract: Individual feeding behaviours in wide-range feeders may represent unavoidable knowledge for an appropriate understanding of contaminant acquisition, adding complexity to the study of the dynamic of contaminants throughout food chains. In this case study, pollutant body burden of Yellow-legged gull (Larus michahellis) chicks was highly influenced by dietary exposure, whereas the influence of trophic position was relatively low. Display Omitted Highlights: ► Diet origin (δ 34 S) and trophic position (δ 15 N) were tested relative to Hg, Se, and Pb levels. ► Hg and Se concentrations in gull feathers were highly influenced by δ 34 S signatures. ► Exploited habitat influenced pollutant levels to a greater extent than trophic position. ► Biomagnification processes contribute less to contamination exposure in wide-range feeders. - Pollutant body burden of a wide-range

  10. Discovery of a new phase with magnetic short range correlations and its possible relevance for the hidden order in URu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sykora, Steffen [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Becker, Klaus W. [Technische Universitaet Dresden, D-01062 Dresden (Germany)

    2016-07-01

    In this paper we discuss a new phase of the Kondo lattice model which arises from the competition of Kondo and RKKY energy scales. Normally the Kondo lattice model is used to capture the low-energy physics of heavy fermion systems. However, according to the so-called Doniach picture the Kondo state will be replaced by an antiferromagnetic state for the case that the Kondo energy scale becomes smaller than the magnetic interaction between magnetic ions. In the present study we start instead from a modified electronic one-particle dispersion which avoids nesting of particle-hole excitations. Thus the magnetic ordered state should be suppressed which provides an opportunity for the inset of a new low-energy state with competing Kondo and magnetic energies. As will be shown, this new state avoids magnetic symmetry breaking but leads to a number of physical properties which are relevant for the understanding of the hidden order state in URu{sub 2}Si{sub 2}.

  11. 1.55-μm mode-locked quantum-dot lasers with 300 MHz frequency tuning range

    Energy Technology Data Exchange (ETDEWEB)

    Sadeev, T., E-mail: tagir@mailbox.tu-berlin.de; Arsenijević, D.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin (Germany); Franke, D.; Kreissl, J.; Künzel, H. [Heinrich-Hertz-Institut, Einsteinufer 37, 10587 Berlin (Germany)

    2015-01-19

    Passive mode-locking of two-section quantum-dot mode-locked lasers grown by metalorganic vapor phase epitaxy on InP is reported. 1250-μm long lasers exhibit a wide tuning range of 300 MHz around the fundamental mode-locking frequency of 33.48 GHz. The frequency tuning is achieved by varying the reverse bias of the saturable absorber from 0 to −2.2 V and the gain section current from 90 to 280 mA. 3 dB optical spectra width of 6–7 nm leads to ex-facet optical pulses with full-width half-maximum down to 3.7 ps. Single-section quantum-dot mode-locked lasers show 0.8 ps broad optical pulses after external fiber-based compression. Injection current tuning from 70 to 300 mA leads to 30 MHz frequency tuning.

  12. 1.55-μm mode-locked quantum-dot lasers with 300 MHz frequency tuning range

    International Nuclear Information System (INIS)

    Sadeev, T.; Arsenijević, D.; Bimberg, D.; Franke, D.; Kreissl, J.; Künzel, H.

    2015-01-01

    Passive mode-locking of two-section quantum-dot mode-locked lasers grown by metalorganic vapor phase epitaxy on InP is reported. 1250-μm long lasers exhibit a wide tuning range of 300 MHz around the fundamental mode-locking frequency of 33.48 GHz. The frequency tuning is achieved by varying the reverse bias of the saturable absorber from 0 to −2.2 V and the gain section current from 90 to 280 mA. 3 dB optical spectra width of 6–7 nm leads to ex-facet optical pulses with full-width half-maximum down to 3.7 ps. Single-section quantum-dot mode-locked lasers show 0.8 ps broad optical pulses after external fiber-based compression. Injection current tuning from 70 to 300 mA leads to 30 MHz frequency tuning

  13. Lower Hybrid Frequency Range Waves Generated by Ion Polarization Drift Due to Electromagnetic Ion Cyclotron Waves: Analysis of an Event Observed by the Van Allen Probe B

    Science.gov (United States)

    Khazanov, G. V.; Boardsen, S.; Krivorutsky, E. N.; Engebretson, M. J.; Sibeck, D.; Chen, S.; Breneman, A.

    2017-01-01

    We analyze a wave event that occurred near noon between 07:03 and 07:08 UT on 23 February 2014 detected by the Van Allen Probes B spacecraft, where waves in the lower hybrid frequency range (LHFR) and electromagnetic ion cyclotron (EMIC) waves are observed to be highly correlated, with Pearson correlation coefficient of approximately 0.86. We assume that the correlation is the result of LHFR wave generation by the ions polarization drift in the electric field of the EMIC waves. To check this assumption the drift velocities of electrons and H+, He+, and O+ ions in the measured EMIC wave electric field were modeled. Then the LHFR wave linear instantaneous growth rates for plasma with these changing drift velocities and different plasma compositions were calculated. The time distribution of these growth rates, their frequency distribution, and the frequency dependence of the ratio of the LHFR wave power spectral density (PSD)parallel and perpendicular to the ambient magnetic eld to the total PSD were found. These characteristics of the growth rates were compared with the corresponding characteristics of the observed LHFR activity. Reasonable agreement between these features and the strong correlation between EMIC and LHFR energy densities support the assumption that the LHFR wave generation can be caused by the ions polarization drift in the electric field of an EMIC wave.

  14. Band gaps in the low-frequency range based on the two-dimensional phononic crystal plates composed of rubber matrix with periodic steel stubs

    International Nuclear Information System (INIS)

    Yu, Kunpeng; Chen, Tianning; Wang, Xiaopeng

    2013-01-01

    In this paper, the numerical investigation of elastic wave propagation in two-dimensional phononic crystals composed of an array of steel stepped resonators on a thin rubber slab is presented. For the first time the rubber material is used as the matrix of the PCs. With the finite-element method, the dispersion relations of this novel PCs structure and some factors of the band structure are studied. Results show that, with the rubber material as matrix, the PC structures exhibit extremely low-frequency band gaps, in the frequency range of hundreds of Hz or even tens of Hz; the geometrical parameters and the material parameters can modulate the band gaps to different extents. Furthermore, to understand the low-frequency band gaps caused by this new structure, some resonance eigenmodes of the structure are calculated. Results show that the vibration of the unit cell of the structure can be seen as several mass–spring systems, in which the vibration of the steel stepped resonator decides the lower boundary of the first band gap and the vibration of the rubber that is not in contact with the resonator decides the upper boundary

  15. A novel method for determining calibration and behavior of PVDF ultrasonic hydrophone probes in the frequency range up to 100 MHz.

    Science.gov (United States)

    Bleeker, H J; Lewin, P A

    2000-01-01

    A new calibration technique for PVDF ultrasonic hydrophone probes is described. Current implementation of the technique allows determination of hydrophone frequency response between 2 and 100 MHz and is based on the comparison of theoretically predicted and experimentally determined pressure-time waveforms produced by a focused, circular source. The simulation model was derived from the time domain algorithm that solves the non linear KZK (Khokhlov-Zabolotskaya-Kuznetsov) equation describing acoustic wave propagation. The calibration technique data were experimentally verified using independent calibration procedures in the frequency range from 2 to 40 MHz using a combined time delay spectrometry and reciprocity approach or calibration data provided by the National Physical Laboratory (NPL), UK. The results of verification indicated good agreement between the results obtained using KZK and the above-mentioned independent calibration techniques from 2 to 40 MHz, with the maximum discrepancy of 18% at 30 MHz. The frequency responses obtained using different hydrophone designs, including several membrane and needle probes, are presented, and it is shown that the technique developed provides a desirable tool for independent verification of primary calibration techniques such as those based on optical interferometry. Fundamental limitations of the presented calibration method are also examined.

  16. Laboratory-grown coccoliths exhibit no vital effect in clumped isotope (Δ47) composition on a range of geologically relevant temperatures

    Science.gov (United States)

    Katz, Amandine; Bonifacie, Magali; Hermoso, Michaël; Cartigny, Pierre; Calmels, Damien

    2017-07-01

    The carbonate clumped isotope (or Δ47) thermometer relies on the temperature dependence of the abundance of 13C18O16O22- ion groups within the mineral lattice. This proxy shows tremendous promise to reconstruct past sea surface temperatures (SSTs), but requires calibration of the relationship between Δ47 and calcification temperatures. Specifically, it is important to determine whether biologically-driven fractionation (the so-called "vital effect") overprints Δ47 values, as reported in some biominerals such as the foraminifera and the coccoliths for the carbon and oxygen isotope systems. Despite their abundance in the pelagic environment, coccolithophores have not been comprehensively investigated to test the reliability of coccolith Δ47-inferred temperatures. In this study, we cultured three geologically-relevant coccolith species (Emiliania huxleyi, Coccolithus pelagicus, and Calcidiscus leptoporus) at controlled temperatures between 7 and 25 ± 0.2 °C. Other variables such as pCO2, pH, alkalinity, nutrient concentrations and salinity were kept constant at mean present-day oceanic conditions. Although cultured coccoliths exhibit substantial species-specific oxygen and carbon isotope vital effects, we found that their Δ47 composition follows a statistically indistinguishable relationship with 1/T2 for all three species, indicating a lack of interspecific vital effects in coccoliths. Further, the Δ47 composition of coccolith calcite is identical to inorganic calcite precipitated at the same temperature, indicating an overall absence of clumped isotope vital effect in coccolith biominerals. From a paleoceanographic perspective, this study indicates that the Δ47 values of sedimentary coccoliths - even from highly diverse/mixed assemblages - can be analyzed to reconstruct SSTs with confidence, as such temperature estimates are not biased by taxonomic content or changing interspecies vital effects through time.

  17. Age dependence of dielectric properties of bovine brain and ocular tissues in the frequency range of 400 MHz to 18 GHz

    International Nuclear Information System (INIS)

    Schmid, Gernot; Ueberbacher, Richard

    2005-01-01

    In order to identify possible age-dependent dielectric properties of brain and eye tissues in the frequency range of 400 MHz to 18 GHz, measurements on bovine grey and white matter as well as on cornea, lens (cortical) and the vitreous body were performed using a commercially available open-ended coaxial probe and a computer-controlled vector network analyser. Freshly excised tissues of 52 animals of two age groups (42 adult animals, i.e. 16-24 month old and 10 young animals, i.e. 4-6 month old calves) were examined within 8 min (brain tissue) and 15 min (eye tissue), respectively, of the animals' death. Tissue temperatures for the measurements were 32 ± 1 0 C and 25 ± 1 0 C for brain and eye tissues, respectively. Statistical analysis of the measured data revealed significant differences in the dielectric properties of white matter and cortical lens tissue between the adult and the young group. In the case of white matter the mean values of conductivity and permittivity of young tissue were 15%-22% and 12%-15%, respectively, higher compared to the adult tissue in the considered frequency range. Similarly, young cortical lens tissue was 25%-76% higher in conductivity and 27%-39% higher in permittivity than adult cortical lens tissue

  18. Influence of vegetation physiognomy, elevation and fire frequency on medium and large mammals in two protected areas of the Espinhaço Range

    Directory of Open Access Journals (Sweden)

    Fernando Ferreira de Pinho

    2017-05-01

    Full Text Available ABSTRACT The objectives of this study were to determine the richness of medium and large mammal species in two protected areas of the Espinhaço Mountain Range, state of Minas Gerais, Brazil; and to investigate the factors affecting the occurrence of those species. To accomplish that we placed 49 camera traps activated by heat and motion at Rio Preto State Park (RPSP and 48 at Sempre Vivas National Park (SVNP. We also collected data on three environmental variables: vegetation physiognomy, elevation and wildfire frequency, to evaluate the influence of these factors on species richness and use intensity (inferred from camera trap detection rate by large mammals. We recorded 23 large mammal species in the two parks combined. The lowest species richness was found at the rupestrian habitat of RPSP, and in the open grasslands of SVNP. The forest and savannah physiognomies were used more intensively by large mammals. Species richness was higher and use was greater at lower elevations of RPSP. In SVNP, fire frequency did not affect species richness or use intensity. The savannah habitat had very similar richness compared to the forests of the two protected areas. The high species richness and use intensity observed in these forest habitats highlights the importance of riparian environments in the Cerrado biome. The highest species richness and use intensity observed at low elevation follows patterns found in the literature, probably due to variation in the vegetation, which results in greater resource availability. Although rupestrian habitats at high elevations of the Espinhaço Range are known to have a high degree of endemism for some taxa, large mammal richness and use were not high in this habitat. These results indicate that the protection of native vegetation at lower elevations is crucial for the long-term conservation of large mammals in the Espinhaço Range.

  19. Health effects from long-range transported contaminants in Arctic top predators: An integrated review based on studies of polar bears and relevant model species.

    Science.gov (United States)

    Sonne, Christian

    2010-07-01

    The aim of this review is to provide a thorough overview of the health effects from the complexed biomagnified mixture of long-range transported industrial organochlorines (OCs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs) and mercury (Hg) on polar bear (Ursus maritimus) health. Multiple scientific studies of polar bears indicate negative relationships between exposure to these contaminants and health parameters; however, these are all of a correlative nature and do not represent true cause-and-effects. Therefore, information from controlled studies of farmed Norwegian Arctic foxes (Vulpes lagopus) and housed East and West Greenland sledge dogs (Canis familiaris) were included as supportive weight of evidence in the clarification of contaminant exposure and health effects in polar bears. The review showed that hormone and vitamin concentrations, liver, kidney and thyroid gland morphology as well as reproductive and immune systems of polar bears are likely to be influenced by contaminant exposure. Furthermore, exclusively based on polar bear contaminant studies, bone density reduction and neurochemical disruption and DNA hypomethylation of the brain stem seemed to occur. The range of tissue concentration, at which these alterations were observed in polar bears, were ca. 1-70,000 ng/g lw for OCs (blood plasma concentrations of some PCB metabolites even higher), ca. 1-1000 ng/g lw for PBDEs and for PFCs and Hg 114-3052 ng/g ww and 0.1-50 microg/g ww, respectively. Similar concentrations were found in farmed foxes and housed sledge dogs while the lack of dose response designs did not allow an estimation of threshold levels for oral exposure and accumulated tissue concentrations. Nor was it possible to pinpoint a specific group of contaminants being more important than others nor analyze their interactions. For East Greenland polar bears the corresponding daily SigmaOC and SigmaPBDE oral exposure was estimated to be 35 and 0.34 microg/kg body

  20. A study of three-half-turn and frame antennae for ion cyclotron range of frequency plasma heating in the URAGAN-3M torsatron

    International Nuclear Information System (INIS)

    Lysoivan, A.I.; Moiseenko, V.E.; Plyusnin, V.V.; Kasilov, S.V.; Bondarenko, V.N.; Chechkin, V.V.; Fomin, I.P.; Grigor'eva, L.I.; Konovalov, V.G.; Koval'ov, S.V.; Litvinov, A.P.; Mironov, Yu.K.; Nazarov, N.I.; Pavlichenko, O.S.; Pavlichenko, R.O.; Shapoval, A.N.; Skibenko, A.I.; Volkov, E.D.

    1995-01-01

    Numerical and experimental results of Alfven wave heating of plasmas in the frequency range below the ion cyclotron frequency (ω ci ) are presented. Two different types of antenna were used for plasma production and heating: a frame type antenna (FTA) conventionally used in the URAGAN-3M device and a three-half-turn antenna (THTA) proposed recently to avoid the deleterious effects of conversion of fast wave to slow wave in the plasma periphery and to perform plasma core heating more effectively. Numerical modeling of electromagnetic field excitation in the URAGAN-3M plasma by the FTA and THTA was performed using a one-dimensional code. The results of calculations showed better performance of the compact THTA compared with the FTA for the case of a high density plasma (approximately 10 13 cm -3 ). When using the THTA, the experiments performed showed the possibility of dense plasma production (more than 2x10 13 cm -3 ) and heating, which had not been obtained earlier in the URAGAN-3M. Shifting the power deposition profile deeper inside the plasma body with the THTA resulted in modification of the plasma density profile and an improvement in plasma confinement. ((orig.))

  1. Wireless network of stand-alone end effect probes for soil in situ permittivity measurements over the 100MHZ-6GHz frequency range

    Science.gov (United States)

    Demontoux, François; Bircher, Simone; Ruffié, Gilles; Bonnaudiin, Fabrice; Wigneron, Jean-Pierre; Kerr, Yann

    2017-04-01

    Microwave remote sensing and non-destructive analysis are a powerful way to provide properties estimation of materials. Numerous applications using microwave frequency behavior of materials (remote sensing above land surfaces, non-destructive analysis…) are strongly dependent on the material's permittivity (i.e. dielectric properties). This permittivity depends on numerous parameters such as moisture, texture, temperature, frequency or bulk density. Permittivity measurements are generally carried out in the laboratory. Additionally, dielectric mixing models allow, over a restricted range of conditions, the assessment of a material's permittivity. in-situ measurements are more difficult to obtain. Some in situ measurement probes based on permittivity properties of soil exist (e.g. Time Domain Reflectometers and Transmissometers, capacitance and impedance sensors). They are dedicated to the acquisition of soil moisture data based on permittivity (mainly the real part) estimations over a range of frequencies from around 50 MHz to 1 or 2 GHz. Other Dielectric Assessment Kits exist but they are expensive and they are rather dedicated to laboratory measurements. Furthermore, the user can't address specific issues related to particular materials (e.g. organic soils) or specific measurement conditions (in situ long time records). At the IMS Laboratory we develop probes for in situ soil permittivity measurements (real and imaginary parts) in the 0.5 - 6 GHz frequency range. They are based on the end effect phenomenon of a coaxial waveguide and so are called end effect probes in this paper. The probes can be connected to a portable Vector Network Analyzer (VNA, ANRITSU MS2026A) for the S11 coefficient measurements needed to compute permittivity. It is connected to a PC to record data using an USB connection. This measurement set-up is already used for in situ measurement of soil properties in the framework of the European Space Agency's (ESA) SMOS space mission. However

  2. An algorithm for the analysis of inductive antennas of arbitrary cross-section for heating in the ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Colestock, P.L.

    1986-10-01

    The application of Ion Cyclotron Range of Frequency (ICRF) heating to near ignited plasmas will require launching structures that will be capable of withstanding the harsh plasma environment. The recessed antenna configuration is expected to provide sufficient protection for the structure, but to date no analysis has been done to determine if adequate coupling can be achieved in such a configuration. In this work we present a method for determining the current distribution for the antenna in the direction transverse to current flow and predict antenna loading in the presence of plasma. Antennas of arbitrary cross section are analyzed above ground planes of arbitrary shape. Results from ANDES, the ANtenna DESign code, are presented and compared to experimental results

  3. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Noterdaeme, J.-M.

    2015-01-01

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k // ) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (k tor ). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k // as strap phasing is moved away from the dipole configuration. This result is the opposite of the k tor trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k // , as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas’ operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to address this issue

  4. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    Science.gov (United States)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Noterdaeme, J.-M.

    2015-11-01

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k//) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (ktor). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k// as strap phasing is moved away from the dipole configuration. This result is the opposite of the ktor trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k//, as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas' operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to address this issue.

  5. Thermal Conductance and High-Frequency Properties of Cryogenic Normal or Superconducting Semi-rigid Coaxial Cables in the Temperature Range of 1-8 K

    Science.gov (United States)

    Kushino, A.; Kasai, S.; Ukibe, M.; Ohkubo, M.

    2018-04-01

    In this study, the characteristics of thin semi-rigid cables composed of different conductors and with outer diameters ranging from 0.86 to 1.19 mm were investigated at low temperatures. The thermal conductance was measured between approximately 1 and 8 K, and the frequency dependence of the attenuation in the cables was obtained at 3 K. The electrical conductors used in the cables were alloys: beryllium copper, brass, stainless steel (SUS304), phosphor bronze, cupronickel (CuNi), and niobium-titanium (NbTi). The thermal conductance of a commercial miniature coaxial cable with braided wires forming the outer electrical conductor was also examined for reference. The measured thermal conductance was compared to published data and that generated from material libraries and databases. Among the measured cables using normal metals, the semi-rigid cable composed of SUS304 conductors and a polytetrafluoroethylene insulator showed the lowest thermal conductance. The transmission performance of the semi-rigid cables using SUS304 or CuNi was improved by plating the central conductors with a silver coating of approximately 3 μm thickness, and their thermal conductance with the plating increased by approximately one order of magnitude. The superconducting NbTi semi-rigid cable exhibited the lowest thermal conductance of all the cables considered in the present study along with very small attenuation up to above 5 GHz.

  6. Enroute NASA/FAA low-frequency propfan test in Alabama (October 1987): A versatile atmospheric aircraft long-range noise prediction system

    Science.gov (United States)

    Tsouka, Despina G.

    In order to obtain a flight-to-static noise prediction of an advanced Turboprop (propfan) Aircraft, FAA went on an elaboration of the data that were measured during a full scale measuring program that was conducted by NASA and FAA/DOT/TSC on October 1987 in Alabama. The elaboration process was based on aircraft simulation to a point source, on an atmospheric two dimensional noise model, on the American National Standard algorithm for the calculation of atmospheric absortion, and on the DOT/TSC convention for ground reflection effects. Using the data of the Alabama measurements, the present paper examines the development of a generalized, flexible and more accurate process for the evaluation of the static and flight low-frequency long-range noise data. This paper also examines the applicability of the assumptions made by the Integrated Noise Model about linear propagation, of the three dimensional Hamiltonian Rays Tracing model and of the Weyl-Van der Pol model. The model proposes some assumptions in order to increase the calculations flexibility without significant loss of accuracy. In addition, it proposes the usage of the three dimensional Hamiltonian Rays Tracing model and the Weyl-Van der Pol model in order to increase the accuracy and to ensure the generalization of noise propagation prediction over grounds with variable impedance.

  7. Electromagnetic shielding behavior of polyaniline using Red Mud (industrial waste) as filler in the X – band (8.2–12.4 GHz) frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Pande, Anu; Gairola, Preeti [Uttaranchal University, Prem Nagar, Dehradun (India); Sambyal, Pradeep [National Physical Laboratory (CSIR), K, S. Krishnan Marg, New Delhi (India); Gairola, S.P., E-mail: spgairola10@gmail.com [Uttaranchal University, Prem Nagar, Dehradun (India); Kumar, Vinod [Centre for Energy Studies, Indian Institute of Technology, New Delhi (India); Singh, Kuldeep [Central Electrochemical Research Institute (CSIR), Karaikudi, Tamilnadu (India); Dhawan, S.K. [National Physical Laboratory (CSIR), K, S. Krishnan Marg, New Delhi (India)

    2017-03-01

    In today’s times where pollution of all kinds is at its peak, numerous efforts are being made to find proper waste disposal methods. Moving on the same lines, this paper presents an economical and environmentally safe method of disposal of red mud to control electromagnetic pollution by using it as an electromagnetic shielding material. Composites of PANI/RM have been prepared by in-situ chemical oxidative polymerization and have been tested for structural analysis, thermal stability and magnetization by XRD, TGA and VSM techniques respectively. Further, the composites have shown shielding effectiveness of 33–41 dB (>99.99% attenuation) in 8.2–12.4 GHz frequency range (X-band) at a thickness of 3 mm which is absorption dominated. Thus, the results conclude that the incorporation of red mud into polymer matrix can serve two purposes – firstly, it can provide a good alternative as a shielding material and secondly, it can prove to be a feasible way of waste disposal. - Highlights: • An attempt to find out application of red mud in controlling electromagnetic pollution. • Waste utilization for technology: Red mud is an insoluble industrial waste used for EMI Shielding application. • Using and testing of Red Mud as filler instead of the other widely used fillers. • Characterization of materials (Red Mud/Polyaniline composite) for EMI shielding Application. • EMI Shielding results discussions of new material (Red Mud/Polyaniline).

  8. Excitation of higher radial modes of azimuthal surface waves in the electron cyclotron frequency range by rotating relativistic flow of electrons in cylindrical waveguides partially filled by plasmas

    Science.gov (United States)

    Girka, Igor O.; Pavlenko, Ivan V.; Thumm, Manfred

    2018-05-01

    Azimuthal surface waves are electromagnetic eigenwaves of cylindrical plasma-dielectric waveguides which propagate azimuthally nearby the plasma-dielectric interface across an axial external stationary magnetic field. Their eigenfrequency in particular can belong to the electron cyclotron frequency range. Excitation of azimuthal surface waves by rotating relativistic electron flows was studied in detail recently in the case of the zeroth radial mode for which the waves' radial phase change within the layer where the electrons gyrate is small. In this case, just the plasma parameters cause the main influence on the waves' dispersion properties. In the case of the first and higher radial modes, the wave eigenfrequency is higher and the wavelength is shorter than in the case of the zeroth radial mode. This gain being of interest for practical applications can be achieved without any change in the device design. The possibility of effective excitation of the higher order radial modes of azimuthal surface waves is demonstrated here. Getting shorter wavelengths of the excited waves in the case of higher radial modes is shown to be accompanied by decreasing growth rates of the waves. The results obtained here are of interest for developing new sources of electromagnetic radiation, in nano-physics and in medical physics.

  9. Comprehensive genomic profiling of 295 cases of clinically advanced urothelial carcinoma of the urinary bladder reveals a high frequency of clinically relevant genomic alterations.

    Science.gov (United States)

    Ross, Jeffrey S; Wang, Kai; Khaira, Depinder; Ali, Siraj M; Fisher, Huge A G; Mian, Badar; Nazeer, Tipu; Elvin, Julia A; Palma, Norma; Yelensky, Roman; Lipson, Doron; Miller, Vincent A; Stephens, Philip J; Subbiah, Vivek; Pal, Sumanta K

    2016-03-01

    In the current study, the authors present a comprehensive genomic profile (CGP)-based study of advanced urothelial carcinoma (UC) designed to detect clinically relevant genomic alterations (CRGAs). DNA was extracted from 40 µm of formalin-fixed, paraffin-embedded sections from 295 consecutive cases of recurrent/metastatic UC. CGP was performed on hybridization-captured, adaptor ligation-based libraries to a mean coverage depth of 688X for all coding exons of 236 cancer-related genes plus 47 introns from 19 genes frequently rearranged in cancer, using process-matched normal control samples as a reference. CRGAs were defined as GAs linked to drugs on the market or currently under evaluation in mechanism-driven clinical trials. All 295 patients assessed were classified with high-grade (International Society of Urological Pathology classification) and advanced stage (stage III/IV American Joint Committee on Cancer) disease, and 294 of 295 patients (99.7%) had at least 1 GA on CGP with a mean of 6.4 GAs per UC (61% substitutions/insertions/deletions, 37% copy number alterations, and 2% fusions). Furthermore, 275 patients (93%) had at least 1 CRGA involving 75 individual genes with a mean of 2.6 CRGAs per UC. The most common CRGAs involved cyclin-dependent kinase inhibitor 2A (CDKN2A) (34%), fibroblast growth factor receptor 3 (FGFR3) (21%), phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) (20%), and ERBB2 (17%). FGFR3 GAs were diverse types and included 10% fusions. ERBB2 GAs were equally divided between amplifications and substitutions. ERBB2 substitutions were predominantly within the extracellular domain and were highly enriched in patients with micropapillary UC (38% of 32 cases vs 5% of 263 nonmicropapillary UC cases; PCancer 2016;122:702-711. © 2015 American Cancer Society. © 2015 American Cancer Society.

  10. Effects of Electromagnetic Field Over a Human Body, Sar Simulation with and Without Nanotextile in the Frequency Range 0.9-1.8GHZ

    Science.gov (United States)

    Tomovski, Boyan; Gräbner, Frank; Hungsberg, Axel; Kallmeyer, Christian; Linsel, Mario

    2011-11-01

    Within only the last decade, usage of mobile phones and many other electronic devices with high speed wireless RF connection is rapidly increasing. Modern life requires reliable, quick and high-quality information connections, which explains the widely spreading craze for electronic mobile devices of various types. The vast technological advances we are witnessing in electronics, electro-optics, and computer science have profoundly affected our everyday lives. Meanwhile, safety concerns regarding the biological effects of electromagnetic (EM) radiation have been raised, in particular at a low level of exposure which we everyday experience. A variety of waves and signals have to be considered such as different sine waves, digital signals used in radio, television, mobile phone systems and other information transfer systems. The field around us has become rather complicated and the "air space is getting more and more dense with RF. The establishing of safety recommendations, law norms and rules augmented by adequate measurements is very important and requires quite an expertise. But as many scientific researches suggest, what we are currently witnessing is very likely to generate a great public danger and a bad influence over the human body. There are many health organisations warning the public for possible development of cancer, mental and physical disorders etc [7, 8]. These suggestions are quite serious and should not be neglected by the official bodies and the test laboratories. In the following work, the effects of electromagnetic field over a virtual model of a human head have been simulated in the frequency range from 900 MHz to 1800 MHz (commonly created in the real life by mobile GSM system) with the help of the program MEFiSTo 2D Classic [1]. The created virtual models using the 2D simulation & computation software proved that the use of new high tech nanotextile materials for shielding layers around the human body can reduce the effects of EM fields

  11. Laser-induced breakdown spectroscopy to monitor ion cyclotron range of frequency wall cleaning Li/D co-deposition in EAST tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Liu, P.; Wu, D.; Sun, L.Y.; Zhao, D.Y.; Hai, R.; Li, C. [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, School of Physics and Optical Electronic Technology, Dalian University of Technology, Dalian, 116024 (China); Ding, H., E-mail: hding@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, School of Physics and Optical Electronic Technology, Dalian University of Technology, Dalian, 116024 (China); Hu, Z.H.; Wang, L.; Hu, J.S.; Chen, J.L.; Luo, G.N. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)

    2017-05-15

    Highlights: • LIBS was applied to EAST for monitoring the cleaning performance of the first wall using He-ICRF cleaning. • The cleaning performance is effective under helium ambient gas and some measurements have been obtained. • The results also indicate that the influence of magnetic field on LIBS signal is much stronger in helium ambient gas. • The effect of delay time and laser fluence on the LIBS signal has been investigated. - Abstract: In this paper, laser-induced breakdown spectroscopy (LIBS) under magnetic field condition has been studied in laboratory and EAST tokamak. The experimental results reveal that in helium ambient gas, the magnetic field significantly enhances the LIBS signal intensity (∼3 times). The effect of time delay and laser fluence on the intensity of LIBS has been investigated for optimizing the signal to background ratio (S/B). The developed LIBS approach has been applied to monitor the cleaning performance of the first wall in the fusion device of EAST using the ion cyclotron range of frequency (ICRF). The experimental results demonstrate that the cleaning performance for Li/D co-deposition layer is effective under helium ambient gas. The removing rate of Li on the surface of W tile is faster than that on Mo tile in He-ICRF cleaning and the D/(D + H) ratio on Mo tile is higher by ∼1.2 times than that on W tile. This work would indicate the feasibility of using LIBS to monitor the wall cleaning processes in EAST tokamak.

  12. INVESTIGATION OF RANGES AND FREQUENCY OF MUTATIONS IN THE embB GENE IN MYCOBACTERIUMTUBERCULOSIS ASSOCIATED WITH RESISTANCE TO ETHAMBUTOL USING REAL-TIME POLYMERASE CHAINREACTION

    Directory of Open Access Journals (Sweden)

    Yu. S. Аlyapkinа

    2017-01-01

    Full Text Available Based on real-time allele-specific polymerase chain reaction, the ranges of potential mutations in codons of 306 and 405 of the embBgene in Mycobacterium tuberculosis associated with resistance to ethambutol were investigated. 5 different mutations were detected in codon 306 and 3 mutations were found in codon 406 of the embB gene. The detected mutations were confirmed by sequencing and mass spectrometry. By analyzing the frequency of detected mutations of , the set of reagents was developed for rapid testing of susceptibility tuberculous mycobacteria to ethambutol by multi-competitive allele-specific real-time PCR. Out of 107 tested specimens of clinical isolates, mutations of the embB gene of M. tuberculosis were detected in 49 (45.8% specimens, and no mutations were found in 58 (52.2% specimens. 39 (36.4% specimens had mutations in codon 306 of the embB gene, and 9 (8.4% specimens had a mutation in codon 406, and 1 (0.9% specimen had mutations in both codons 306 and 406. The high level of agreement in the results of molecular genetic and bacteriological tests (84% proved the significance of mutations in codons 306 and 406 of the embB gene in M. tuberculosis and the need for their identification in order to detect ethambutol resistant strains of M. tuberculosis. When using molecular genetic tests, the sensitivity level made 75.8%, while the specificity of standard culture-based methods makes 95.6%.

  13. Theoretical and experimental study of two-frequency solid-state lasers in the GHz to THz ranges. Opto-microwave applications waves

    International Nuclear Information System (INIS)

    Lai, N.D.

    2003-07-01

    We explored some new features of single- and dual-frequency solid-state lasers oscillating in continuous-wave or pulsed regimes. First, we have developed some techniques to optimise the characteristics of pulsed lasers. A weak modulation of the pump power made it possible to obtain a stable repetition rate with a relative stability of 10 -6 . The pulse duration was continuously controlled from ten nanoseconds to a few hundreds nanoseconds by three different methods: adjustment of the laser beam diameter in the absorber, adjustment of the pump beam diameter in the active medium, and, in particular, the use of forked eigenstates in a two-axis laser. Moreover, the forked eigenstates allows to increase the pulse energy by coherent addition of the pulses. A compact two-frequency Nd:YAG-Cr:YAG laser with a beat note frequency continuously adjustable up to 2,7 GHz was demonstrated. The two-frequency pulses are ideal sources to meet various needs of applications such as the Doppler lidar-radar. Moreover, we show that two-frequency pulses at 1,55 μm can be obtained by using a new c-cut Co:ASL saturable absorber in an Er-Yb:glass laser. These pulses are perfectly adapted to free-space detection systems requiring eye safety. The coherence time of the beat note in these lasers was also studied: it is limited by the pulse duration. A new technique of modulating the pump power of a solid-state laser at frequencies close to its relaxation oscillation frequency was studied and made it possible to generate a beat note coherence from pulse to pulse. Frequency conversion techniques using the nonlinear optical effects make it possible to obtain tunable two-frequency sources in the visible spectrum. Green and red two-frequency pulses were obtained by using different conversion techniques, intra-cavity or extra-cavity. A two-frequency THz source in the red spectrum was also obtained by doubling the frequencies of a two-frequency THz Er-Yb:glass laser using a mixed fan-out PPLN crystal

  14. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  15. Recommended safety procedures for the installation and use of radiofrequency and microwave devices in the frequency range 10 MHz-300 GHz

    International Nuclear Information System (INIS)

    1979-02-01

    Studies of possible hazards to human health from exposure to radio frequency and microwave radiation show that there is a need for controls. Exposure to high levels of radio frequency and microwave radiation over prolonged periods can cause adverse health effects. The type and extent of injury depend not only on the intensity (strength) of the field and the exposure duration but also on various other factors such as the frequency of the radiation, type of modulation, polarization, and distance from the source. (auth)

  16. Laboratory Mid-frequency (Kilohertz) Range Seismic Property Measurements and X-ray CT Imaging of Fractured Sandstone Cores During Supercritical CO2 Injection

    Science.gov (United States)

    Nakagawa, S.; Kneafsey, T. J.; Chang, C.; Harper, E.

    2014-12-01

    During geological sequestration of CO2, fractures are expected to play a critical role in controlling the migration of the injected fluid in reservoir rock. To detect the invasion of supercritical (sc-) CO2 and to determine its saturation, velocity and attenuation of seismic waves can be monitored. When both fractures and matrix porosity connected to the fractures are present, wave-induced dynamic poroelastic interactions between these two different types of rock porosity—high-permeability, high-compliance fractures and low-permeability, low-compliance matrix porosity—result in complex velocity and attenuation changes of compressional waves as scCO2 invades the rock. We conducted core-scale laboratory scCO2 injection experiments on small (diameter 1.5 inches, length 3.5-4 inches), medium-porosity/permeability (porosity 15%, matrix permeability 35 md) sandstone cores. During the injection, the compressional and shear (torsion) wave velocities and attenuations of the entire core were determined using our Split Hopkinson Resonant Bar (short-core resonant bar) technique in the frequency range of 1-2 kHz, and the distribution and saturation of the scCO2 determined via X-ray CT imaging using a medical CT scanner. A series of tests were conducted on (1) intact rock cores, (2) a core containing a mated, core-parallel fracture, (3) a core containing a sheared core-parallel fracture, and (4) a core containing a sheared, core-normal fracture. For intact cores and a core containing a mated sheared fracture, injections of scCO2 into an initially water-saturated sample resulted in large and continuous decreases in the compressional velocity as well as temporary increases in the attenuation. For a sheared core-parallel fracture, large attenuation was also observed, but almost no changes in the velocity occurred. In contrast, a sample containing a core-normal fracture exhibited complex behavior of compressional wave attenuation: the attenuation peaked as the leading edge of

  17. The changes of the frequency specific impedance of the human body due to the resonance in the kHz range in cancer diagnostics

    Science.gov (United States)

    Michalak, K. P.; Nawrocka-Bogusz, H.

    2011-12-01

    The frequency-specific absorption of kHz signals has been postulated for different tissues, trace elements, vitamins, toxins, pathogens, allergens etc. for low-power (μV) signals. An increase in the impedance of the human body is observed only up to the given power of the applied signal. The highest amplification of the given signal being damped by the body makes it possible to determine the intensity of the given process in the body (e.g. amount of the toxin, trace element, intensity of the allergy) being connected with a given frequency spectrum of the signal. The mechanism of frequency-specific absorption can be explained by means of the Quantum Field Theory being applied to the structure of the water. Substantially high coincidence between the frequencies of the rotation of free quasi-excited electrons in coherent domains of water and the frequencies being used in the MORA diagnostics (Med-Tronic GmbH, EN ISO 13485, EN ISO 9001) can be observed. These frequencies are located in the proximity of f = 7kHz · i (i = 1,3,5,7,...). This fact suggests that the coherent domains with the admixtures of the given substances create structure-specific coherent domains that possess frequency-specific absorption spectra. The diagnostic tool called "MORA System diagnosis" was used to investigate 102 patients with different types and stages of cancer. Many signals were observed to be absorbed by many cancer patients, e.g.: 'Cellular defense system', 'Degeneration tendencies', Manganese, Magnesium, Zinc, Selenium, Vitamin E, Glutamine, Glutathione, Cysteine, Candida albicans, Mycosis. The results confirm the role of oxidative stress, immunological system deficiency and mitochondria malfunction in the development of cancer.

  18. Equivalent threshold sound pressure levels for Sennheiser HDA 200 earphone and Etymotic Research ER-2 insert earphone in the frequency range 125 Hz to 16 kHz

    DEFF Research Database (Denmark)

    Han, Loc A; Poulsen, Torben

    1998-01-01

    Equivalent Threshold Sound Pressure Levels (ETSPLs) have been determined for the Sennheiser HDA 200 earphone and the Etymotic Research ER-2insert earphone. Thirty-one young normal-hearing test subjects participated and the thresholds were determined for all recommended frequencies in thefrequency...

  19. Electric field of the power terrestrial sources observed by microsatellite Chibis-M in the Earth's ionosphere in frequency range 1-60 Hz

    Science.gov (United States)

    Dudkin, Fedir; Korepanov, Valery; Dudkin, Denis; Pilipenko, Vyacheslav; Pronenko, Vira; Klimov, Stanislav

    2015-07-01

    The power line emission (PLE) 50/60 Hz and the Schumann resonance (SR) harmonics were detected by the use of a compact electrical field sensor of length 0.42 m during microsatellite Chibis-M mission in years 2012-2014. The initial orbit of Chibis-M has altitude 500 km and inclination 52°. We present the space distribution of PLE and its connections with the possible overhead power lines. PLE has been recorded both in the shade and sunlit parts of the orbits as opposed to SR which have been recorded only in the nightside of the Earth. The cases of an extra long distance of PLE propagation in the Earth's ionosphere and increased value of SR Q factor have been also observed. These results should stimulate the ionosphere model refinement for ultralow frequency and extremely low frequency electromagnetic wave propagation as well as a study on new possibility of the ionosphere diagnostics.

  20. Human exposure standards in the frequency range 1 Hz To 100 kHz: the case for adoption of the IEEE standard.

    Science.gov (United States)

    Patrick Reilly, J

    2014-10-01

    Differences between IEEE C95 Standards (C95.6-2002 and C95.1-2005) in the low-frequency (1 Hz-100 kHz) and the ICNIRP-2010 guidelines appear across the frequency spectrum. Factors accounting for lack of convergence include: differences between the IEEE standards and the ICNIRP guidelines with respect to biological induction models, stated objectives, data trail from experimentally derived thresholds through physical and biological principles, selection and justification of safety/reduction factors, use of probability models, compliance standards for the limbs as distinct from the whole body, defined population categories, strategies for central nervous system protection below 20 Hz, and correspondence of environmental electric field limits with contact currents. This paper discusses these factors and makes the case for adoption of the limits in the IEEE standards.

  1. Characterization of the electromagnetic near-field absorption in layered biological tissue in the frequency range from 30 MHz to 6000 MHz

    Energy Technology Data Exchange (ETDEWEB)

    Christ, A [Foundation for Research on Information Technologies in Society (IT' IS), Zeughausstr 43, 8004 Zurich (Switzerland); Samaras, T [Radiocommunications Laboratory, Aristotle University of Thessaloniki, 541 24 Thessaloniki (Greece); Klingenboeck, A [Foundation for Research on Information Technologies in Society (IT' IS), Zeughausstr 43, 8004 Zurich (Switzerland); Kuster, N [Foundation for Research on Information Technologies in Society (IT' IS), Zeughausstr 43, 8004 Zurich (Switzerland)

    2006-10-07

    Currently, standards for the compliance testing of wireless devices are being extended to cover a wider frequency band and different usage patterns of mobile phones as well as of novel body-worn and handheld devices. As a consequence, not only the head but also strongly varying tissue distributions of the body are exposed to electromagnetic radiation. Several authors have reported changes in the SAR absorption of body tissue due to the presence of a low permittivity fat layer. This paper identifies two different effects which can lead to increased SAR in layered tissue in comparison to the SAR assessed using homogeneous tissue simulating liquid: (1) for larger distances between the tissue and the antenna, standing wave effects occur depending on the frequency and fat layer thickness. (2) In the very close near-field (distances approximately {lambda}/40), reactive E-field components lead to high local absorption in the skin. The latter effect occurs at lower frequencies and depends on the antenna type. Modification of the parameters of the homogeneous liquids cannot compensate for these effects. However, a conservative exposure estimate can be obtained by applying a multiplication factor between 1 and 3 to the values assessed using current experimental dosimetric techniques.

  2. A High-Speed High-Frequency Broadband Acoustic Modem for Short-to-Medium Range Data Transmission in Ports, Very Shallow Waters and Deep Waters Using Spread-Spectrum Modulation and Decision Feedback Equalizing

    National Research Council Canada - National Science Library

    Beaujean, Pierre-Philippe; Spruance, John; Kriel, Dion

    2006-01-01

    ...: The long-term objective is the commercialization of a high-speed high-frequency acoustic modem transmitting data at true rates of up to 105,000 bps, at a maximum range of 500 m and operate between 240 kHz and 380 kHz...

  3. Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz

    DEFF Research Database (Denmark)

    Poulsen, Torben; Oakley, Sebastian

    2009-01-01

    Hearing threshold sound pressure levels were measured for the Sennheiser HDA 280 audiometric earphone. Hearing thresholds were measured for 25 normal hearing test subjects at the 11 audiometric test frequencies from 125 Hz to 8000 Hz. Sennheiser HDA 280 is a supra-aural earphone that may be seen...... as a substitute for the classical Telephonics TDH 39. The results are given as the Equivalent Threshold Sound Pressure Level, ETSPL, measured in an acoustic coupler specified in IEC 60318-3. The results are in good agreement with an independent investigation from PTB, Braunschweig, Germany. From acoustic...

  4. Towards terahertz detection and calibration through spontaneous parametric down-conversion in the terahertz idler-frequency range generated by a 795 nm diode laser system

    Directory of Open Access Journals (Sweden)

    Vladimir V. Kornienko

    2018-05-01

    Full Text Available We study a calibration scheme for terahertz wave nonlinear-optical detectors based on spontaneous parametric down-conversion. Contrary to the usual low wavelength pump in the green, we report here on the observation of spontaneous parametric down-conversion originating from an in-growth poled lithium niobate crystal pumped with a continuous wave 50 mW, 795 nm diode laser system, phase-matched to a terahertz frequency idler wave. Such a system is more compact and allows for longer poling periods as well as lower losses in the crystal. Filtering the pump radiation by a rubidium-87 vapor cell allowed the frequency-angular spectra to be obtained down to ∼0.5 THz or ∼1 nm shift from the pump radiation line. The presence of an amplified spontaneous emission “pedestal” in the diode laser radiation spectrum significantly hampers the observation of spontaneous parametric down-conversion spectra, in contrast to conventional narrowband gas lasers. Benefits of switching to longer pump wavelengths are pointed out, such as collinear optical-terahertz phase-matching in bulk crystals.

  5. Towards terahertz detection and calibration through spontaneous parametric down-conversion in the terahertz idler-frequency range generated by a 795 nm diode laser system

    Science.gov (United States)

    Kornienko, Vladimir V.; Kitaeva, Galiya Kh.; Sedlmeir, Florian; Leuchs, Gerd; Schwefel, Harald G. L.

    2018-05-01

    We study a calibration scheme for terahertz wave nonlinear-optical detectors based on spontaneous parametric down-conversion. Contrary to the usual low wavelength pump in the green, we report here on the observation of spontaneous parametric down-conversion originating from an in-growth poled lithium niobate crystal pumped with a continuous wave 50 mW, 795 nm diode laser system, phase-matched to a terahertz frequency idler wave. Such a system is more compact and allows for longer poling periods as well as lower losses in the crystal. Filtering the pump radiation by a rubidium-87 vapor cell allowed the frequency-angular spectra to be obtained down to ˜0.5 THz or ˜1 nm shift from the pump radiation line. The presence of an amplified spontaneous emission "pedestal" in the diode laser radiation spectrum significantly hampers the observation of spontaneous parametric down-conversion spectra, in contrast to conventional narrowband gas lasers. Benefits of switching to longer pump wavelengths are pointed out, such as collinear optical-terahertz phase-matching in bulk crystals.

  6. Radio-Wave Tomography of Inhomogeneities in Biological Media with Multi-Frequency Sounding in the Range 2-8 GHZ

    Directory of Open Access Journals (Sweden)

    Shipilov Sergey

    2018-01-01

    Full Text Available In this paper, a method for detecting and mapping inhomogeneities in biological tissues using the radio-wave tomosynthesis method is presented. The proposed method of radio-wave tomosynthesis allows us to calculate the three-dimensional distribution of the permittivity of the space under study and, thereby, to detect tissue inhomogeneities and to determine their location and size. Due to their harmlessness for humans, these methods are suitable for dynamic observation of changes in the size of formation, in contrast to x-ray methods, for which regular doses of ionizing radiation are contraindicated. Therefore, the development of non-invasive methods for the search for inhomogeneities in biological media based on radio-wave sounding, which makes it possible to identify pathological formations, is now very relevant.

  7. Pengaruh Frekuensi Pemutaran Telur terhadap Daya Tetas dan Bobot Badan DOC Ayam Kampung (The Effect of Egg Centrifugation Frequency on Hatchability and Body Weight DOC of Free-range Chicken)

    OpenAIRE

    Bachari, Irawati; Sembiring, Iskandar; Tarigan, Dedi Suranta

    2010-01-01

    The objective of research would be to assess the extent to which the effect of a good egg centrifugation frequency and interaction on hatchability of Free-range Chicken eggs.This research was conducted by using the factorial complete random sampling. The treatment was frequency of egg centrifugation with three levels of rotation, I, e., RI (4 times/day), R2 (8 times/day), R3 (12 times/day).The result of research indicated that highest hatchability was found in treatment of egg centrifuga...

  8. Introduction to natural disturbances and historic range of variation: type, frequency, severity, and post-disturbance structure in central hardwood forests

    Science.gov (United States)

    Katie Greenberg; Beverly S. Collins; Henry McNab; Douglas K. Miller; Gary R. Wein

    2015-01-01

    EXCERPT FROM: Natural Disturbances and Historic Range Variation 2015. Throughout the history of upland hardwood forests of the Central Hardwood Region, natural disturbances have been integral to shaping forest structure and composition, and essential in maintaining diverse biotic...

  9. Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz.

    Science.gov (United States)

    Poulsen, Torben; Oakley, Sebastian

    2009-05-01

    Hearing threshold sound pressure levels were measured for the Sennheiser HDA 280 audiometric earphone. Hearing thresholds were measured for 25 normal-hearing test subjects at the 11 audiometric test frequencies from 125 Hz to 8000 Hz. Sennheiser HDA 280 is a supra-aural earphone that may be seen as a substitute for the classical Telephonics TDH 39. The results are given as the equivalent threshold sound pressure level (ETSPL) measured in an acoustic coupler specified in IEC 60318-3. The results are in good agreement with an independent investigation from PTB, Braunschweig, Germany. From acoustic laboratory measurements ETSPL values are calculated for the ear simulator specified in IEC 60318-1. Fitting of earphone and coupler is discussed. The data may be used for a future update of the RETSPL standard for supra-aural audiometric earphones, ISO 389-1.

  10. A high-efficiency low-voltage class-E PA for IoT applications in sub-1 GHz frequency range

    Science.gov (United States)

    Zhou, Chenyi; Lu, Zhenghao; Gu, Jiangmin; Yu, Xiaopeng

    2017-10-01

    We present and propose a complete and iterative integrated-circuit and electro-magnetic (EM) co-design methodology and procedure for a low-voltage sub-1 GHz class-E PA. The presented class-E PA consists of the on-chip power transistor, the on-chip gate driving circuits, the off-chip tunable LC load network and the off-chip LC ladder low pass filter. The design methodology includes an explicit design equation based circuit components values' analysis and numerical derivation, output power targeted transistor size and low pass filter design, and power efficiency oriented design optimization. The proposed design procedure includes the power efficiency oriented LC network tuning, the detailed circuit/EM co-simulation plan on integrated circuit level, package level and PCB level to ensure an accurate simulation to measurement match and first pass design success. The proposed PA is targeted to achieve more than 15 dBm output power delivery and 40% power efficiency at 433 MHz frequency band with 1.5 V low voltage supply. The LC load network is designed to be off-chip for the purpose of easy tuning and optimization. The same circuit can be extended to all sub-1 GHz applications with the same tuning and optimization on the load network at different frequencies. The amplifier is implemented in 0.13 μm CMOS technology with a core area occupation of 400 μm by 300 μm. Measurement results showed that it provided power delivery of 16.42 dBm at antenna with efficiency of 40.6%. A harmonics suppression of 44 dBc is achieved, making it suitable for massive deployment of IoT devices. Project supported by the National Natural Science Foundation of China (No. 61574125) and the Industry Innovation Project of Suzhou City of China (No. SYG201641).

  11. Dissociative photoionization of IBr following I(4d) and Br(3d) inner-shell excitations in the range of 60 ∼ 133 eV: remarkable biased charge spread relevant to the core-hole states

    International Nuclear Information System (INIS)

    Boo, Bong Hyun; Koyano, Inosuke

    2002-01-01

    Dissociative photoionization of an interhalogen molecule, iodine monobromide (IBr), spanning the I(4d) and the Br(3d) inner-shell excitation/ionization regions has been studied by using time-of-flight (TOF) mass spectrometry coupled to synchrotron radiation in the range of 60 ∼ 133 eV. The total and the individual photoion yields have been recorded as functions of the photon energy. Here, a giant shape resonance has been observed owing to the I(4d 10 ) →I(4d 9 εf) transition, the transition probability for which outweighs that for the Br(3d 10 ) →Br(3d 9 εf) excitation. In addition to the huge resonance, discrete resonances owing to the Br(3d) -1 IBr(4pσ + ) and the Br(3d -1 )Br(5p) transitions, with very weak intensities, are observed at 70.5 and 73.6 eV and have spin-orbit splittings of = 1.0 and = 0.9 eV, respectively. The dissociation processes of singly and doubly charged parent ions have also been evaluated from the variations of the individual ion and photoion-photoion coincidence (PIPICO) yields with the photon energy. Below the Br(3d) threshold, including the Br(3d) discrete excitation region, 60 + and I 2+ ions are exclusively formed with a trace number of Br + ions. Slightly above the Br(3d) threshold, more specifically at 77.5 eV, however, photoionization events leading to the formations of Br + and Br 2- prevail. At higher energies beyond the Br(3d) threshold, 78 + and I 2+ turn out to exceed again those for Br + and Br 2+ , respectively. Over the entire energy range examined, a remarkable biased charge spread in dissociative photoionization events is observed, presumably reflecting the fact that charge localized mostly in the excited atoms relevant to the specific inner-shell excitation, which can be accounted for mainly by a two-step decay process via a fast dissociation followed by autoionization upon vuv absorption

  12. The "long tail" of the protein tumbling correlation function: observation by (1)H NMR relaxometry in a wide frequency and concentration range.

    Science.gov (United States)

    Roos, Matthias; Hofmann, Marius; Link, Susanne; Ott, Maria; Balbach, Jochen; Rössler, Ernst; Saalwächter, Kay; Krushelnitsky, Alexey

    2015-12-01

    Inter-protein interactions in solution affect the auto-correlation function of Brownian tumbling not only in terms of a simple increase of the correlation time, they also lead to the appearance of a weak slow component ("long tail") of the correlation function due to a slowly changing local anisotropy of the microenvironment. The conventional protocol of correlation time estimation from the relaxation rate ratio R1/R2 assumes a single-component tumbling correlation function, and thus can provide incorrect results as soon as the "long tail" is of relevance. This effect, however, has been underestimated in many instances. In this work we present a detailed systematic study of the tumbling correlation function of two proteins, lysozyme and bovine serum albumin, at different concentrations and temperatures using proton field-cycling relaxometry combined with R1ρ and R2 measurements. Unlike high-field NMR relaxation methods, these techniques enable a detailed study of dynamics on a time scale longer than the normal protein tumbling correlation time and, thus, a reliable estimate of the parameters of the "long tail". In this work we analyze the concentration dependence of the intensity and correlation time of the slow component and perform simulations of high-field (15)N NMR relaxation data demonstrating the importance of taking the "long tail" in the analysis into account.

  13. Fundamental processes of fuel removal by cyclotron frequency range plasmas and integral scenario for fusion application studied with carbon co-deposits

    Energy Technology Data Exchange (ETDEWEB)

    Möller, S., E-mail: s.moeller@fz-juelich.de [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich (Germany); Wauters, T. [Laboratory for Plasma Physics, ERM/KMS, TEC Partner, 1000 Brussels (Belgium); Kreter, A. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich (Germany); Petersson, P.; Carrasco, A.G. [Fusion Plasma Physics, KTH Royal Institute of Technology, Teknikringen 31, 10044 Stockholm (Sweden)

    2015-08-15

    Plasma impact removal using radio frequency heated plasmas is a candidate method to control the co-deposit related tritium inventory in fusion devices. Plasma parameters evolve according to the balance of input power to losses (transport, radiation, collisions). Material is sputtered by the ion fluxes with impact energies defined by the plasma sheath. H{sub 2}, D{sub 2} and {sup 18}O{sub 2} plasmas are produced in the carbon limiter tokamak TEXTOR. Pre-characterised a-C:D layers are exposed to study local removal rates. The D{sub 2} plasma exhibits the highest surface release rate of 5.7 ± 0.9 ∗ 10{sup 19} D/m{sup 2}s. Compared to this the rate of the O{sub 2} plasma is 3-fold smaller due to its 11-fold lower ion flux density. Re-deposition of removed carbon is observed, indicating that pumping and ionisation are limiting the removal in TEXTOR. Presented models can explain the observations and allow tailoring removal discharges. An integral application scenario using ICWC and thermo-chemical removal is presented, allowing to remove 700 g T from a-C:DT co-deposits in 20 h with fusion compatible wall conditions using technical specifications similar to ITER.

  14. Reduced-order computational model in nonlinear structural dynamics for structures having numerous local elastic modes in the low-frequency range. Application to fuel assemblies

    International Nuclear Information System (INIS)

    Batou, A.; Soize, C.; Brie, N.

    2013-01-01

    Highlights: • A ROM of a nonlinear dynamical structure is built with a global displacements basis. • The reduced order model of fuel assemblies is accurate and of very small size. • The shocks between grids of a row of seven fuel assemblies are computed. -- Abstract: We are interested in the construction of a reduced-order computational model for nonlinear complex dynamical structures which are characterized by the presence of numerous local elastic modes in the low-frequency band. This high modal density makes the use of the classical modal analysis method not suitable. Therefore the reduced-order computational model is constructed using a basis of a space of global displacements, which is constructed a priori and which allows the nonlinear dynamical response of the structure observed on the stiff part to be predicted with a good accuracy. The methodology is applied to a complex industrial structure which is made up of a row of seven fuel assemblies with possibility of collisions between grids and which is submitted to a seismic loading

  15. Reduced-order computational model in nonlinear structural dynamics for structures having numerous local elastic modes in the low-frequency range. Application to fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Batou, A., E-mail: anas.batou@univ-paris-est.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee (France); Soize, C., E-mail: christian.soize@univ-paris-est.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee (France); Brie, N., E-mail: nicolas.brie@edf.fr [EDF R and D, Département AMA, 1 avenue du général De Gaulle, 92140 Clamart (France)

    2013-09-15

    Highlights: • A ROM of a nonlinear dynamical structure is built with a global displacements basis. • The reduced order model of fuel assemblies is accurate and of very small size. • The shocks between grids of a row of seven fuel assemblies are computed. -- Abstract: We are interested in the construction of a reduced-order computational model for nonlinear complex dynamical structures which are characterized by the presence of numerous local elastic modes in the low-frequency band. This high modal density makes the use of the classical modal analysis method not suitable. Therefore the reduced-order computational model is constructed using a basis of a space of global displacements, which is constructed a priori and which allows the nonlinear dynamical response of the structure observed on the stiff part to be predicted with a good accuracy. The methodology is applied to a complex industrial structure which is made up of a row of seven fuel assemblies with possibility of collisions between grids and which is submitted to a seismic loading.

  16. Comparison of measurement standards of the acoustic pressure in air in the low frequency range: COOMET.AUV.A-K2

    Science.gov (United States)

    Chalyy, V.

    2011-01-01

    A bilateral regional comparison of national microphone standards from 2 Hz to 250 Hz was carried out between the DP NDI 'Systema' (Ukraine) and the VNIIFTRI (Russia) from July to September 2009. The comparison, COOMET.AUV.A-K2, was based on the pressure calibration of laboratory standard microphones type LSIP. The comparison results have been linked to the established key comparison reference value (KCRV) of CCAUV.A-K2. The degrees of equivalence, expressed as the deviation from the established KCRV and its expanded uncertainty (k = 2), have been determined, and the comparison result is in agreement with the KCRV within the estimated uncertainties at all employed frequencies. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  17. COOMET pilot comparison 473/RU-a/09: Comparison of hydrophone calibrations in the frequency range 250 Hz to 200 kHz

    Science.gov (United States)

    Yi, Chen; Isaev, A. E.; Yuebing, Wang; Enyakov, A. M.; Teng, Fei; Matveev, A. N.

    2011-01-01

    A description is given of the COOMET project 473/RU-a/09: a pilot comparison of hydrophone calibrations at frequencies from 250 Hz to 200 kHz between Hangzhou Applied Acoustics Research Institute (HAARI, China)—pilot laboratory—and Russian National Research Institute for Physicotechnical and Radio Engineering Measurements (VNIIFTRI, Designated Institute of Russia of the CIPM MRA). Two standard hydrophones, B&K 8104 and TC 4033, were calibrated and compared to assess the current state of hydrophone calibration of HAARI (China) and Russia. Three different calibration methods were applied: a vibrating column method, a free-field reciprocity method and a comparison method. The standard facilities of each laboratory were used, and three different sound fields were applied: pressure field, free-field and reverberant field. The maximum deviation of the sensitivities of two hydrophones between the participants' results was 0.36 dB. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCAUV-KCWG.

  18. The Kepler Mission: A Mission to Determine the Frequency of Inner Planets Near the Habitable Zone of a Wide Range of Stars

    Science.gov (United States)

    Borucki, W. J.; Koch, D. G.; Dunham, E. W.; Jenkins, J. M.

    1997-01-01

    The surprising discovery of giant planets in inner orbits around solar-like stars has brought into question our understanding of the development and evolution of planetary systems, including our solar system. To make further progress, it is critical to detect and obtain data on the frequency and characteristics of Earth-class planets. The Kepler Mission is designed to be a quick, low-cost approach to accomplish that objective. Transits by Earth-class planets produce a fractional change. in stellar brightness of 5 x 10(exp -5) to 40 x 10(exp -5) lasting for 4 to 16 hours. From the period and depth of the transits, the orbit and size of the planets can be calculated. The proposed instrument is a one-meter aperture photometer with a 12 deg. field-of-view (FOV). To obtain the required precision and to avoid interruptions caused by day-night and seasonal cycles, the photometer will be launched into a heliocentric orbit. It will continuously and simultaneously monitor the flux from 80,000 dwarf stars brighter than 14th magnitude in the Cygnus constellation. The mission tests the hypothesis that the formation of most stars produces Earth-class planets in inner orbits. Based on this assumption and the recent observations that 2% of the stars have giant planets in inner orbits, several types of results are expected from the mission: 1. From transits of Earth-class planets, about 480 planet detections and 60 cases where two or more planets are found in the same system. 2. From transits of giant planets, about 160 detections of inner-orbit planets and 24 detections of outer-orbit planets. 3. From the phase modulation of the reflected light from giant planets, about 1400 planet detections with periods less than a week, albedos for 160 of these giant planets, and densities for seven planets.

  19. The Kepler Mission: A Mission to Determine the Frequency of Inner Planets Neat the Habitable Zone of a Wide Range of Stars

    Science.gov (United States)

    Borucki, W. J.; Koch, D. G.; Dunham, E. W.; Jenkins, J. M.; Young, Richard E. (Technical Monitor)

    1997-01-01

    The surprising discovery of giant planets in inner orbits around solar-like stars has brought into question our understanding of the development and evolution of planetary systems, including our solar system. To make further progress, it is critical to detect and obtain data on the frequency and characteristics of Earth-class planets. The Kepler Mission is designed to be a quick, low-cost approach to accomplish that objective. Transits by Earth-class planets produce a fractional change in stellar brightness of 5 x 10(exp -5) to 40 x 10(exp -5) lasting for 4 to 16 hours, From the period and depth of the transits, the orbit and size of the planets can be calculated. The proposed instrument is a one-meter aperture photometer with a 12 deg field-of-view (FOV). To obtain the required precision and to avoid interruptions caused by day-night and seasonal cycles, the photometer will be launched into a heliocentric orbit. It will continuously and simultaneously monitor the flux from 80,000 dwarf stars brighter than 14th magnitude in the Cygnus constellation. The mission tests the hypothesis that the formation of most stars produces Earth-class planets in inner orbits. Based on this assumption and the recent observations that 2% of the stars have giant planets in inner orbits, several types of results are expected from the mission: 1. From transits of Earth-class planets, about 480 planet detections and 60 cases where two or more planets are found in the same system. 2. From transits of giant planets, about 160 detections of inner-orbit planets and 24 detections of outer-orbit planets. 3. From the phase modulation of the reflected light from giant planets, about 1400 planet detections with periods less than a week, albedos for 160 of these giant planets, and densities for seven planets.

  20. Delivering Microwave Spectroscopy to the Masses: a Design of a Low-Cost Microwave Spectrometer Operating in the 18-26 GHZ Frequency Range

    Science.gov (United States)

    Steber, Amanda; Pate, Brooks

    2014-06-01

    Advances in chip-level microwave technology in the communications field have led to the possibilities of low cost alternatives for current Fourier transform microwave (FTMW) spectrometers. Many of the large, expensive microwave components in a traditional design can now be replaced by robust, mass market monolithic microwave integrated circuits (MMICs). "Spectrometer on a board" designs are now feasible that offer dramatic cost reduction for microwave spectroscopy. These chip-level components can be paired with miniature computers to produce compact instruments that are operable through USB. A FTMW spectrometer design using the key MMIC components that drive cost reduction will be presented. Two dual channel synthesizers (Valon Technology Model 5008), a digital pattern generator (Byte Paradigm Wav Gen Xpress), and a high-speed digitizer/arbitrary waveform generator combination unit (Tie Pie HS-5 530 XM) form the key components of the spectrometer for operation in the 18-26.5 GHz range. The design performance is illustrated using a spectrometer that is being incorporated into a museum display for astrochemistry. For this instrument a user interface, developed in Python, has been developed and will be shown.

  1. Transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz

    Science.gov (United States)

    Zaldívar Huerta, Ignacio E.; Pérez Montaña, Diego F.; Nava, Pablo Hernández; Juárez, Alejandro García; Asomoza, Jorge Rodríguez; Leal Cruz, Ana L.

    2013-12-01

    We experimentally demonstrate the use of an electro-optical transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz. The frequency response of the microwave photonic filter consists of four band-pass windows centered at frequencies that can be tailored to the function of the spectral free range of the optical source, the chromatic dispersion parameter of the optical fiber used, as well as the length of the optical link. In particular, filtering effect is obtained by the interaction of an externally modulated multimode laser diode emitting at 1.5 μm associated to the length of a dispersive optical fiber. Filtered microwave signals are used as electrical carriers to transmit TV-signal over long-haul optical links point-to-point. Transmission of TV-signal coded on the microwave band-pass windows located at 4.62, 6.86, 4.0 and 6.0 GHz are achieved over optical links of 25.25 km and 28.25 km, respectively. Practical applications for this approach lie in the field of the FTTH access network for distribution of services as video, voice, and data.

  2. Radio Frequency Ranging for Swarm Relative Localization

    Science.gov (United States)

    2017-10-01

    NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) October 2017 2. REPORT TYPE Technical Report 3. DATES COVERED (From - To...doi: 10.1109/CDC.2004 .1428700. 5. Fresconi F, Fermen-Coker M. Delivery of modular lethality via a parent-child concept. Proceedings of the AIAA...setup() { // put your setup code here, to run once: Serial.begin(115200); Serial3.begin(115200); Serial3. write ("SFAC\\r\

  3. Time-domain analysis of frequency dependent inertial wave forces on cylinders

    DEFF Research Database (Denmark)

    Krenk, Steen

    2013-01-01

    a simple time-domain procedure for the inertial force, in which the frequency dependence is represented via a simple explicit time filter on the wave particle acceleration or velocity. The frequency dependence of the inertia coefficient is known analytically as a function of the wave......-number, and the relevant range of waves shorter than about six times the diameter typically corresponds to deep water waves. This permits a universal non-dimensional frequency representation, that is converted to rational form to provide the relevant filter equation. Simple time-domain simulations demonstrate...... the reduction of the resonant part of the response for natural structural frequencies above the dominating wave frequency....

  4. Wrist range of motion and motion frequency during toy and game play with a joint-specific controller specially designed to provide neuromuscular therapy: A proof of concept study in typically developing children.

    Science.gov (United States)

    Crisco, Joseph J; Schwartz, Joel B; Wilcox, Bethany; Brideau, Holly; Basseches, Benjamin; Kerman, Karen

    2015-08-20

    Upper extremities affected by hemiplegic cerebral palsy (CP) and other neuromuscular disorders have been demonstrated to benefit from therapy, and the greater the duration of the therapy, the greater the benefit. A great motivator for participating in and extending the duration of therapy with children is play. Our focus is on active motion therapy of the wrist and forearm. In this study we examine the wrist motions associated with playing with two toys and three computer games controlled by a specially-designed play controller. Twenty children (ages 5-11) with no diagnosis of a muscular disorder were recruited. The play controller was fitted to the wrist and forearm of each child and used to measure and log wrist flexion and extension. Play activity and enjoyment were quantified by average wrist range of motion (ROM), motion frequency measures, and a discrete visual scale. We found significant differences in the average wrist ROM and motion frequency among the toys and games, yet there were no differences in the level of enjoyment across all toys and games, which was high. These findings indicate which toys and games may elicit the greater number of goal-directed movements, and lay the foundation for our long-term goal to develop and evaluate innovative motion-specific play controllers that are engaging rehabilitative devices for enhancing therapy and promoting neural plasticity and functional recovery in children with CP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Power-law spectra found in plant signal of the Borssele NPP. An analysis using wavelet. Application of wavelet for wide-frequency range investigation and investigation (spectrum) for the secondary system signals

    International Nuclear Information System (INIS)

    Suzudo, T.; Verhoef, J.P.; Tuerkcan, E.

    1996-09-01

    Power-law spectra were found in the temperature signals of the secondary loop in the Borssele Nuclear Power Plant, a PWR in the Netherlands. The coolant temperature before the steam generator inlet was found to fluctuate such that its power spectrum density S, follows S∝f -α , where α is ∝4/3. Analyses using PSD suggested that the value of α is roughly constant over years. Detailed analyses were conducted using wavelet, with the discovery that the power-law appears constantly only at around 0.1 Hz, and the estimated α was found between 1.26 and 1.36. The feedwater pressure signal and feedwater flow rate signal in the same frequency range were white noise and Borwnian motion respectively, and the indication of α=4/3 was not found from them. (orig.)

  6. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  7. Why relevance theory is relevant for lexicography

    DEFF Research Database (Denmark)

    Bothma, Theo; Tarp, Sven

    2014-01-01

    This article starts by providing a brief summary of relevance theory in information science in relation to the function theory of lexicography, explaining the different types of relevance, viz. objective system relevance and the subjective types of relevance, i.e. topical, cognitive, situational...... that is very important for lexicography as well as for information science, viz. functional relevance. Since all lexicographic work is ultimately aimed at satisfying users’ information needs, the article then discusses why the lexicographer should take note of all these types of relevance when planning a new...... dictionary project, identifying new tasks and responsibilities of the modern lexicographer. The article furthermore discusses how relevance theory impacts on teaching dictionary culture and reference skills. By integrating insights from lexicography and information science, the article contributes to new...

  8. Smoking status and self-reported race affect the frequency of clinically relevant oncogenic alterations in non-small-cell lung cancers at a United States-based academic medical practice.

    Science.gov (United States)

    Yamaguchi, Norihiro; Vanderlaan, Paul A; Folch, Erik; Boucher, David H; Canepa, Hannah M; Kent, Michael S; Gangadharan, Sidharta P; Majid, Adnan; Kocher, Olivier N; Goldstein, Michael A; Huberman, Mark S; Costa, Daniel B

    2013-10-01

    The identification of somatic genomic aberrations in non-small-cell lung cancer (NSCLC) is part of evidence-based practice guidelines for care of patients with NSCLC. We sought to establish the frequency and correlates with these changes in routine patient-tumor sample pairs. Clinicopathologic data and tumor genotype were retrospectively compiled and analyzed from an overall cohort of 381 patient-tumor samples. Of these patients, 75.9% self-reported White race, 13.1% Asian, 6.5% Black, 27.8% were never-smokers, 54.9% former-smokers and 17.3% current-smokers. The frequency of EGFR mutations was 23.9% (86/359), KRAS mutations 34.2% (71/207) and ALK FISH positivity 9.1% (23/252) in tumor samples, and almost all had mutually exclusive results for these oncogenes. In tumors from White, Black and Asian patients, the frequencies of EGFR mutations were 18.4%, 18.2% and 62%, respectively; of ALK FISH positivity 7.81%, 0% and 14.8%, respectively; and of KRAS mutations 41.6%, 20% and 0%. These patterns changed significant with increasing pack-year history of smoking. In White patients, the frequencies of EGFR mutations and ALK FISH positivity decreased with increasing pack-year cohorts; while the frequencies of KRAS mutations increased. Interestingly, in Asian patients the frequencies of EGFR mutations were similar in never smokers and in the cohorts with less than 45pack-year histories of smoking and only decreased in the 45pack-year plus cohort. The frequencies of somatic EGFR, KRAS, and ALK gene abnormalities using routine lung cancer tissue samples from our United States-based academic medical practice reflect the diverse ethnicity (with a higher frequency of EGFR mutations in Asian patients) and smoking patterns (with an inverse correlation between EGFR mutation and ALK rearrangement) of our tested population. These results may help other medical practices appreciate the expected results from introduction of routine tumor genotyping techniques into their day-to-day care

  9. Deep learning relevance

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Petersen, Casper

    2016-01-01

    train a Recurrent Neural Network (RNN) on existing relevant information to that query. We then use the RNN to "deep learn" a single, synthetic, and we assume, relevant document for that query. We design a crowdsourcing experiment to assess how relevant the "deep learned" document is, compared...... to existing relevant documents. Users are shown a query and four wordclouds (of three existing relevant documents and our deep learned synthetic document). The synthetic document is ranked on average most relevant of all....

  10. Soliton microcomb range measurement

    Science.gov (United States)

    Suh, Myoung-Gyun; Vahala, Kerry J.

    2018-02-01

    Laser-based range measurement systems are important in many application areas, including autonomous vehicles, robotics, manufacturing, formation flying of satellites, and basic science. Coherent laser ranging systems using dual-frequency combs provide an unprecedented combination of long range, high precision, and fast update rate. We report dual-comb distance measurement using chip-based soliton microcombs. A single pump laser was used to generate dual-frequency combs within a single microresonator as counterpropagating solitons. We demonstrated time-of-flight measurement with 200-nanometer precision at an averaging time of 500 milliseconds within a range ambiguity of 16 millimeters. Measurements at distances up to 25 meters with much lower precision were also performed. Our chip-based source is an important step toward miniature dual-comb laser ranging systems that are suitable for photonic integration.

  11. Mean frequency and relative fluorescence intensity measurement of γ-H2AX foci dose response in PBL exposed to γ-irradiation: An inter- and intra-laboratory comparison and its relevance for radiation triage.

    Science.gov (United States)

    Venkateswarlu, Raavi; Tamizh, Selvan G; Bhavani, Manivannan; Kumar, Arun; Alok, Amit; Karthik, Kanagaraj; Kalra, Namita; Vijayalakshmi, J; Paul, Solomon F D; Chaudhury, N K; Venkatachalam, Perumal

    2015-12-01

    Measurement of γ-H2AX protein changes in the peripheral blood lymphocytes (PBL) of individuals exposed to ionizing radiation is a simple, sensitive, and rapid assay for radiation triage and early marker of dose estimation. The qualitative and quantitative measurements of the protein changes were examined using flow cytometry and microscopy. Whole blood and isolated lymphocytes were exposed in vitro between 0.1 and 5 Gy doses of (60) Co γ-radiation at a dose rate of 1 Gy/min. Radiation induced γ-H2AX foci frequency (n = 3) and relative fluorescence intensity (n = 7) in PBL was measured at 0.5 and 2 hrs postexposure. The observed dose response for γ-H2AX foci frequency at both time points, for whole blood and isolated lymphocytes did not show any significant (P > 0.05) differences. However, when compared with γ-H2AX foci frequency scored manually (microscopy), the semiautomated analysis (captured images) showed a better correlation (r(2) = 0.918) than that obtained with automated (Metafer) scoring (r(2) = 0.690). It is noteworthy to mention that, the γ-H2AX foci frequency quantified using microscopy showed a dose dependent increase up to 2 Gy and the relative fluorescence intensity (RFI) measured with flow cytometry revealed an increase up to 5 Gy in the PBL exposed in vitro. Moreover, a better correlation was observed between the γ-H2AX foci frequency obtained by manual scoring and RFI (r(2) = 0.910). Kinetic studies showed that the γ-H2AX foci remain more or less unchanged up to 4 hrs and reduces gradually over 48 hrs of postexposure at 37°C. Further, inter and intra-laboratory comparisons showed consistency in the scoring of γ-H2AX foci frequency by manual and semiautomated scoring. The overall results suggest that measurement of γ-H2AX (microscopy and flow cytometry) should be employed within 4 to 6 hrs for a reliable dosimetry either by sharing the work load between the laboratories or investing more manpower; however, triage can be possible even up

  12. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences...

  13. Underwater Ranging

    OpenAIRE

    S. P. Gaba

    1984-01-01

    The paper deals with underwater laser ranging system, its principle of operation and maximum depth capability. The sources of external noise and methods to improve signal-to-noise ratio are also discussed.

  14. LOW FREQUENCY DAMPER

    Directory of Open Access Journals (Sweden)

    Radu BOGATEANU

    2009-09-01

    Full Text Available The low frequency damper is an autonomous equipment for damping vibrations with the 1-20Hz range.Its autonomy enables the equipment to be located in various mechanical systems, without requiring special hydraulic installations.The low frequency damper was designed for damping the low frequency oscillations occurring in the circuit controls of the upgraded IAR-99 Aircraft.The low frequency damper is a novelty in the aerospace field ,with applicability in several areas as it can be built up in an appropriate range of dimensions meeting the requirements of different beneficiaries. On this line an equipment able to damp an extended frequency range was performed for damping oscillations in the pipes of the nuclear power plants.This damper, tested in INCAS laboratories matched the requirements of the beneficiary.The low frequency damper is patented – the patent no. 114583C1/2000 is held by INCAS.

  15. Methodical assessment of all non-ionizing radiation sources that can provide a relevant contribution to public exposure. Final report

    International Nuclear Information System (INIS)

    Bornkessel, Christian; Schubert, Markus; Wuschek, Matthias; Brueggemeyer, Hauke; Weiskopf, Daniela

    2011-01-01

    The aim of the research project was to systematically identify artificial sources on non-ionizing radiation (electric, magnetic or electromagnetic fields in a frequency range from 0 Hz to 300 GHz, as well optical radiation in a wavelength range from 100 nm to 1 mm), that have relevant contribution to public exposure. The report includes the following chapters: (1) Concept for the relevance assessment for non-ionizing radiation sources; (2) concept for the systematic identification of sources from establishes technologies; (3) concept for the systematic identification of sources from new or foreseeable technologies; (4)overview of relevant radiation sources.

  16. Understanding synthesis imaging dynamic range

    Science.gov (United States)

    Braun, R.

    2013-03-01

    We develop a general framework for quantifying the many different contributions to the noise budget of an image made with an array of dishes or aperture array stations. Each noise contribution to the visibility data is associated with a relevant correlation timescale and frequency bandwidth so that the net impact on a complete observation can be assessed when a particular effect is not captured in the instrumental calibration. All quantities are parameterised as function of observing frequency and the visibility baseline length. We apply the resulting noise budget analysis to a wide range of existing and planned telescope systems that will operate between about 100 MHz and 5 GHz to ascertain the magnitude of the calibration challenges that they must overcome to achieve thermal noise limited performance. We conclude that calibration challenges are increased in several respects by small dimensions of the dishes or aperture array stations. It will be more challenging to achieve thermal noise limited performance using 15 m class dishes rather than the 25 m dishes of current arrays. Some of the performance risks are mitigated by the deployment of phased array feeds and more with the choice of an (alt,az,pol) mount, although a larger dish diameter offers the best prospects for risk mitigation. Many improvements to imaging performance can be anticipated at the expense of greater complexity in calibration algorithms. However, a fundamental limitation is ultimately imposed by an insufficient number of data constraints relative to calibration variables. The upcoming aperture array systems will be operating in a regime that has never previously been addressed, where a wide range of effects are expected to exceed the thermal noise by two to three orders of magnitude. Achieving routine thermal noise limited imaging performance with these systems presents an extreme challenge. The magnitude of that challenge is inversely related to the aperture array station diameter.

  17. Frequency specific modulation of human somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Matteo eFeurra

    2011-02-01

    Full Text Available Oscillatory neuronal activities are commonly observed in response to sensory stimulation. However, their functional roles are still the subject of debate. One way to probe the roles of oscillatory neural activities is to deliver alternating current to the cortex at biologically relevant frequencies and examine whether such stimulation influences perception and cognition. In this study, we tested whether transcranial alternating current stimulation (tACS over the primary somatosensory cortex (SI could elicit tactile sensations in humans in a frequency dependent manner. We tested the effectiveness of tACS over SI at frequency bands ranging from 2 to 70 Hz. Our results show that stimulation in alpha (10-14 Hz and high gamma (52-70 Hz frequency range produces a tactile sensation in the contralateral hand. A weaker effect was also observed for beta (16-20 Hz stimulation. These findings highlight the frequency-dependency of effective tACS over SI with the effective frequencies corresponding to those observed in previous EEG/MEG studies of tactile perception. Our present study suggests that tACS could be used as a powerful online stimulation technique to reveal the causal roles of oscillatory brain activities.

  18. Hemodynamic changes induced by preventive exposure to terahertz radiation at a frequency range corresponding to molecular emission and absorption spectrum of nitric oxide in animals under conditions of acute stress.

    Science.gov (United States)

    Kirichuck, V F; Velikanova, T S; Ivanov, A N

    2011-06-01

    We studied the influence of preventive irradiation with terahertz electromagnetic waves at frequencies corresponding to nitric oxide emission and absorption molecular spectrum (150,176-150,664 GHz) on hemodynamic parameters in arteries of albino rats upon acute immobilization stress. We showed that exposure to the specified frequencies can produce adaptogenic effect manifesting in the absence of post-stress changes in the linear, systolic, and diastolic blood flow velocities and pressure gradient in various blood vessels of experimental animals.

  19. Frequency Hopping Transceiver Multiplexer

    Science.gov (United States)

    1983-03-01

    ATC 17 ULR IHQ OCLI CPCTR ULTRA HIGH "OQS" UP TO 4X HIGHER THAN BEST INDUS- TRY STANDARD (ATC 100). MICROWAVE POWER, CURRENT. AND 0 RATINGS5...Q"W were assigned to element (FigC-2); which will be modelled into the transformer previously ment td . The center frequencies, "Q", frequency range...of the TD 1288 system. Temperature stability, change with time or storage. Flexure Frequency, or non-linear change over bandwidth. * Humidity

  20. Making Deferred Taxes Relevant

    NARCIS (Netherlands)

    Brouwer, Arjan; Naarding, Ewout

    2018-01-01

    We analyse the conceptual problems in current accounting for deferred taxes and provide solutions derived from the literature in order to make International Financial Reporting Standards (IFRS) deferred tax numbers value-relevant. In our view, the empirical results concerning the value relevance of

  1. Parsimonious relevance models

    NARCIS (Netherlands)

    Meij, E.; Weerkamp, W.; Balog, K.; de Rijke, M.; Myang, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

    2008-01-01

    We describe a method for applying parsimonious language models to re-estimate the term probabilities assigned by relevance models. We apply our method to six topic sets from test collections in five different genres. Our parsimonious relevance models (i) improve retrieval effectiveness in terms of

  2. Relevância clínica e frequência de padrões citoplasmático e pontilhado fino denso observados em FAN-HEp-2 Clinical relevance and frequency of cytoplasmic and nuclear dense fine speckled patterns observed in ANA-HEp-2

    Directory of Open Access Journals (Sweden)

    Andréia Martini Pazini

    2010-12-01

    Full Text Available OBJETIVOS: O presente estudo procurou determinar a frequência e relacionar o título sorológico dos padrões de imunofluorescência para citoplasma celular e nuclear pontilhado fino denso com possível correlação clínica. MÉTODOS: No período entre 2007 a 2009 foram avaliados os resultados de 2.788 testes sorológicos para pesquisa de autoanticorpos pela técnica de imunofluorescência indireta (IFI, utilizando como substrato células HEp-2, realizados no LAC-HUSM/UFSM. RESULTADOS: Entre as amostras analisadas, 1.998 resultaram não reagentes para a pesquisa de autoanticorpos. Entre as amostras reagentes (n = 790 foram encontradas 57 (7,2% amostras apresentando padrão de reatividade descrita como pontilhado fino denso (SFD (3,8% ou fluorescência citoplasmática (Cit (3,4%. Nas amostras com padrão SFD (n = 29, nove apresentaram título 1/160 apenas um não apresentava DAI. Entre as amostras com padrão Cit (n = 27, 20 apresentavam título 1/160 tinham relato de DAI. CONCLUSÃO: Os resultados encontrados ratificam o valor de 1/160 como melhor ponto de corte para definição de presença de DAI, para qualquer um dos padrões de fluorescência avaliados. Contudo, deve-se prestar atenção a títulos inferiores, principalmente para IFI Cit, uma vez que apenas 40% não apresentavam relato de DAI presenteOBJECTIVES: This study aimed to determine the frequency and antibody titers of nuclear dense fine and cytoplasmic patterns with possible clinical correlation. METHODS: From 2007 to 2009, the results of 2,788 autoantibody serological tests were assessed by indirect immunofluorescence (IIF at LAC-HUSM/UFSM, using as substrate HEp-2. RESULTS: Among the analyzed samples, 1,998 of them were negative for autoantibodies. Among the positive samples (n = 790, we found 57 (7.2% showing reactivity pattern described as dense fine speckled (DFS (3.8%, or cytoplasmic (Cit fluorescence (3.4%. In samples with standard DFS (n = 29, nine had titers of 1

  3. Parametric effects of word frequency effect in memory for mixed frequency lists

    OpenAIRE

    Lohnas, Lynn J.; Kahana, Michael J.

    2013-01-01

    The word frequency paradox refers to the finding that low frequency words are better recognized than high frequency words yet high frequency words are better recalled than low frequency words. Rather than comparing separate groups of low and high frequency words, we sought to quantify the functional relation between word frequency and memory performance across the broad range of frequencies typically used in episodic memory experiments. Here we report that both low frequency and high frequenc...

  4. Low Frequency Space Array

    International Nuclear Information System (INIS)

    Dennison, B.; Weiler, K.W.; Johnston, K.J.

    1987-01-01

    The Low Frequency Space Array (LFSA) is a conceptual mission to survey the entire sky and to image individual sources at frequencies between 1.5 and 26 MHz, a frequency range over which the earth's ionosphere transmits poorly or not at all. With high resolution, high sensitivity observations, a new window will be opened in the electromagnetic spectrum for astronomical investigation. Also, extending observations down to such low frequencies will bring astronomy to the fundamental limit below which the galaxy becomes optically thick due to free-free absorption. A number of major scientific goals can be pursued with such a mission, including mapping galactic emission and absorption, studies of individual source spectra in a frequency range where a number of important processes may play a role, high resolution imaging of extended sources, localization of the impulsive emission from Jupiter, and a search for coherent emission processes. 19 references

  5. Culturally Relevant Cyberbullying Prevention

    OpenAIRE

    Phillips, Gregory John

    2017-01-01

    In this action research study, I, along with a student intervention committee of 14 members, developed a cyberbullying intervention for a large urban high school on the west coast. This high school contained a predominantly African American student population. I aimed to discover culturally relevant cyberbullying prevention strategies for African American students. The intervention committee selected video safety messages featuring African American actors as the most culturally relevant cyber...

  6. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  7. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  8. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  9. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  10. Electric current - frequency converter

    International Nuclear Information System (INIS)

    Kumahara, Tadashi; Kinbana, Setsuro.

    1967-01-01

    Herein disclosed is an improved simple electric current-frequency converter, the input current and output frequency linearity of which is widened to a range of four to five figures while compensating, for temperature. The converter may be used for computor processing and for telemetering the output signals from a nuclear reactor. The converter is an astable multivibrator which includes charging circuits comprising emitter-voltage compensated NPN transistors, a charged voltage detecting circuit of temperature compensated field effect transistors, and a transistor switching circuit for generating switching pulses independent of temperature. The converter exhibited a 0.7% frequency change within a range of 5 - 45 0 C and less than a 0.1% frequency drift after six hours of operation when the input current was maintained constant. (Yamaguchi, T.)

  11. Is Information Still Relevant?

    Science.gov (United States)

    Ma, Lia

    2013-01-01

    Introduction: The term "information" in information science does not share the characteristics of those of a nomenclature: it does not bear a generally accepted definition and it does not serve as the bases and assumptions for research studies. As the data deluge has arrived, is the concept of information still relevant for information…

  12. Initiating events frequency determination

    International Nuclear Information System (INIS)

    Simic, Z.; Mikulicic, V.; Vukovic, I.

    2004-01-01

    The paper describes work performed for the Nuclear Power Station (NPS). Work is related to the periodic initiating events frequency update for the Probabilistic Safety Assessment (PSA). Data for all relevant NPS initiating events (IE) were reviewed. The main focus was on events occurring during most recent operating history (i.e., last four years). The final IE frequencies were estimated by incorporating both NPS experience and nuclear industry experience. Each event was categorized according to NPS individual plant examination (IPE) initiating events grouping approach. For the majority of the IE groups, few, or no events have occurred at the NPS. For those IE groups with few or no NPS events, the final estimate was made by means of a Bayesian update with general nuclear industry values. Exceptions are rare loss-of-coolant-accidents (LOCA) events, where evaluation of engineering aspects is used in order to determine frequency.(author)

  13. Clinical Relevance of Adipokines

    Directory of Open Access Journals (Sweden)

    Matthias Blüher

    2012-10-01

    Full Text Available The incidence of obesity has increased dramatically during recent decades. Obesity increases the risk for metabolic and cardiovascular diseases and may therefore contribute to premature death. With increasing fat mass, secretion of adipose tissue derived bioactive molecules (adipokines changes towards a pro-inflammatory, diabetogenic and atherogenic pattern. Adipokines are involved in the regulation of appetite and satiety, energy expenditure, activity, endothelial function, hemostasis, blood pressure, insulin sensitivity, energy metabolism in insulin sensitive tissues, adipogenesis, fat distribution and insulin secretion in pancreatic β-cells. Therefore, adipokines are clinically relevant as biomarkers for fat distribution, adipose tissue function, liver fat content, insulin sensitivity, chronic inflammation and have the potential for future pharmacological treatment strategies for obesity and its related diseases. This review focuses on the clinical relevance of selected adipokines as markers or predictors of obesity related diseases and as potential therapeutic tools or targets in metabolic and cardiovascular diseases.

  14. Information Needs/Relevance

    OpenAIRE

    Wildemuth, Barbara M.

    2009-01-01

    A user's interaction with a DL is often initiated as the result of the user experiencing an information need of some kind. Aspects of that experience and how it might affect the user's interactions with the DL are discussed in this module. In addition, users continuously make decisions about and evaluations of the materials retrieved from a DL, relative to their information needs. Relevance judgments, and their relationship to the user's information needs, are discussed in this module. Draft

  15. Frequency spirals

    International Nuclear Information System (INIS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-01-01

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  16. Frequency spirals

    Energy Technology Data Exchange (ETDEWEB)

    Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

    2016-09-15

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  17. Equivalent magnetic noise reduction at high frequency range due to polarized direction optimization in Terfenol-D/Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} magnetoelectric laminate sensors

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Cong, E-mail: fangcong86@gmail.com [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Ma, Jiashuai; Yao, Meng [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Di, Wenning; Lin, Di; Xu, Haiqing; Wang, Wei [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); Luo, Haosu, E-mail: hsluo@mail.sic.ac.cn [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2017-02-01

    In this paper, we investigate the responsivities and output voltage noise power spectral densities of magnetoelectric (ME) laminate sensors, consisting of length magnetized Terfenol-D alloys and transverse/width poled Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} (PMNT) crystals (i.e. L-T mode and L-W mode respectively), which are directly integrated with custom-build low noise charge amplifier circuits. Both the theoretical analyses and experimental results prove that the L-W mode sensor with the optimized polarized direction of the PMNT plate possesses lower magnetic detection limit at the interested high frequency range of 10 kHz≤f≤50 kHz. The equivalent magnetic noise (EMN) of the L-W mode sensor is 0.78 pT/Hz{sup 1/2} at 30 kHz, which is about 1.7 times lower than the 1.35 pT/Hz{sup 1/2} for conventional L-T mode sensor. Furthermore, an effective method of using operational amplifiers with low equivalent input noise voltage and employing ME laminate composites with high voltage coefficient to reduce the EMNs of the ME laminate sensors at high frequency range has been established. - Highlights: • We present fabrications and properties of the L-T and L-T mode ME composites. • The equivalent magnetic noise levels at high frequency are measured. • The equivalent magnetic noise of the L-W mode sensor is 0.78 pT/Hz{sup 1/2} at 30 kHz. • The dominated noise source can be confirmed from OPA at high frequency range.

  18. Astrophysical relevance of γ transition energies

    International Nuclear Information System (INIS)

    Rauscher, Thomas

    2008-01-01

    The relevant γ energy range is explicitly identified where additional γ strength must be located to have an impact on astrophysically relevant reactions. It is shown that folding the energy dependences of the transmission coefficients and the level density leads to maximal contributions for γ energies of 2≤E γ ≤4 unless quantum selection rules allow isolated states to contribute. Under this condition, electric dipole transitions dominate. These findings allow us to more accurately judge the relevance of modifications of the γ strength for astrophysics

  19. [Relevant public health enteropathogens].

    Science.gov (United States)

    Riveros, Maribel; Ochoa, Theresa J

    2015-01-01

    Diarrhea remains the third leading cause of death in children under five years, despite recent advances in the management and prevention of this disease. It is caused by multiple pathogens, however, the prevalence of each varies by age group, geographical area and the scenario where cases (community vs hospital) are recorded. The most relevant pathogens in public health are those associated with the highest burden of disease, severity, complications and mortality. In our country, norovirus, Campylobacter and diarrheagenic E. coli are the most prevalent pathogens at the community level in children. In this paper we review the local epidemiology and potential areas of development in five selected pathogens: rotavirus, norovirus, Shiga toxin-producing E. coli (STEC), Shigella and Salmonella. Of these, rotavirus is the most important in the pediatric population and the main agent responsible for child mortality from diarrhea. The introduction of rotavirus vaccination in Peru will have a significant impact on disease burden and mortality from diarrhea. However, surveillance studies are needed to determine the impact of vaccination and changes in the epidemiology of diarrhea in Peru following the introduction of new vaccines, as well as antibiotic resistance surveillance of clinical relevant bacteria.

  20. Frequency Constrained ShiftCP Modeling of Neuroimaging Data

    DEFF Research Database (Denmark)

    Mørup, Morten; Hansen, Lars Kai; Madsen, Kristoffer H.

    2011-01-01

    The shift invariant multi-linear model based on the CandeComp/PARAFAC (CP) model denoted ShiftCP has proven useful for the modeling of latency changes in trial based neuroimaging data[17]. In order to facilitate component interpretation we presently extend the shiftCP model such that the extracted...... components can be constrained to pertain to predefined frequency ranges such as alpha, beta and gamma activity. To infer the number of components in the model we propose to apply automatic relevance determination by imposing priors that define the range of variation of each component of the shiftCP model...

  1. CAMAC programmable-control frequency synthesizer

    International Nuclear Information System (INIS)

    Yumaguzin, T.Kh.; Vyazovkin, D.E.; Nazirov, Eh.P.; Tuktarov, R.F.

    1989-01-01

    Synthesizer allows to set frequency with 0.015% accuracy and to scan it with variable step. Frequency controlled divider with further summing-up of divided frequency with fundamental one is used in synthesizer, and it has allowed to use digit of the input code and to obtain 3-4 MHz frequency range. Variation of operation flowsheet in the other frequency range is possible. K-155 and K-531 series microcircuits were used during development

  2. Modulation of the mirror system by social relevance.

    Science.gov (United States)

    Kilner, James M; Marchant, Jennifer L; Frith, Chris D

    2006-09-01

    When we observe the actions of others, certain areas of the brain are activated in a similar manner as to when we perform the same actions ourselves. This 'mirror system' includes areas in the ventral premotor cortex and the inferior parietal lobule. Experimental studies suggest that action observation automatically elicits activity in the observer, which precisely mirrors the activity observed. In this case we would expect this activity to be independent of observer's viewpoint. Here we use whole-head magnetoencephalography (MEG) to record cortical activity of human subjects whilst they watched a series of videos of an actor making a movement recorded from different viewpoints. We show that one cortical response to action observation (oscillatory activity in the 7-12 Hz frequency range) is modulated by the relationship between the observer and the actor. We suggest that this modulation reflects a mechanism that filters information into the 'mirror system', allowing only socially relevant information to pass.

  3. Other relevant biological papers

    International Nuclear Information System (INIS)

    Shimizu, M.

    1989-01-01

    A considerable number of CRESP-relevant papers concerning deep-sea biology and radioecology have been published. It is the purpose of this study to call attention to them. They fall into three general categories. The first is papers of general interest. They are mentioned only briefly, and include text references to the global bibliography at the end of the volume. The second are papers that are not only mentioned and referenced, but for various reasons are described in abstract form. The last is a list of papers compiled by H.S.J. Roe specifically for this volume. They are listed in bibliographic form, and are also included in the global bibliography at the end of the volume

  4. Functionally relevant microsatellites in sugarcane unigenes

    Directory of Open Access Journals (Sweden)

    Singh Nagendra K

    2010-11-01

    Full Text Available Abstract Background Unigene sequences constitute a rich source of functionally relevant microsatellites. The present study was undertaken to mine the microsatellites in the available unigene sequences of sugarcane for understanding their constitution in the expressed genic component of its complex polyploid/aneuploid genome, assessing their functional significance in silico, determining the extent of allelic diversity at the microsatellite loci and for evaluating their utility in large-scale genotyping applications in sugarcane. Results The average frequency of perfect microsatellite was 1/10.9 kb, while it was 1/44.3 kb for the long and hypervariable class I repeats. GC-rich trinucleotides coding for alanine and the GA-rich dinucleotides were the most abundant microsatellite classes. Out of 15,594 unigenes mined in the study, 767 contained microsatellite repeats and for 672 of these putative functions were determined in silico. The microsatellite repeats were found in the functional domains of proteins encoded by 364 unigenes. Its significance was assessed by establishing the structure-function relationship for the beta-amylase and protein kinase encoding unigenes having repeats in the catalytic domains. A total of 726 allelic variants (7.42 alleles per locus with different repeat lengths were captured precisely for a set of 47 fluorescent dye labeled primers in 36 sugarcane genotypes and five cereal species using the automated fragment analysis system, which suggested the utility of designed primers for rapid, large-scale and high-throughput genotyping applications in sugarcane. Pair-wise similarity ranging from 0.33 to 0.84 with an average of 0.40 revealed a broad genetic base of the Indian varieties in respect of functionally relevant regions of the large and complex sugarcane genome. Conclusion Microsatellite repeats were present in 4.92% of sugarcane unigenes, for most (87.6% of which functions were determined in silico. High level of

  5. User perspectives on relevance criteria

    DEFF Research Database (Denmark)

    Maglaughlin, Kelly L.; Sonnenwald, Diane H.

    2002-01-01

    , partially relevant, or not relevant to their information need; and explained their decisions in an interview. Analysis revealed 29 criteria, discussed positively and negatively, that were used by the participants when selecting passages that contributed or detracted from a document's relevance......This study investigates the use of criteria to assess relevant, partially relevant, and not-relevant documents. Study participants identified passages within 20 document representations that they used to make relevance judgments; judged each document representation as a whole to be relevant...... matter, thought catalyst), full text (e.g., audience, novelty, type, possible content, utility), journal/publisher (e.g., novelty, main focus, perceived quality), and personal (e.g., competition, time requirements). Results further indicate that multiple criteria are used when making relevant, partially...

  6. radio frequency based radio frequency based water level monitor

    African Journals Online (AJOL)

    eobe

    ABSTRACT. This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor and .... range the wireless can cover but in this prototype, it ... power supply to the system, the sensed water level is.

  7. ICRF [Ion Cyclotron Range of Frequencies] edge modeling studies

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Colestock, P.L.

    1989-01-01

    Theoretical models have been developed, and are currently being refined, to explain the edge plasma-antenna interaction that occurs during ICRF heating. The periodic structure of a Faraday shielded antenna is found to result in strong ponderomotive force in the vicinity of the antenna. A fluid model, which incorporates the ponderomotive force, shows an increase in transport to the Faraday shield. A kinetic model shows that the strong antenna near fields act to increase the energy of deuterons which strike the shield, thereby increasing the sputtering of shield material. Estimates of edge impurity harmonic heating no significant heating for either in or out-of-phase antenna operation. Additionally, a particle model for electrons near the shield shows that heating results from the parallel electric field associated with the fast wave. A quasilinear model for edge electron heating is presented and compared to the particle calculations. The models' predictions are shown to be consistent with measurements of enhanced transport. 19 refs., 9 figs

  8. Shielding effectiveness research of window panes in microwave frequency range

    OpenAIRE

    Bilotas, Evaldas

    2016-01-01

    The purpose of this work is to investigate microwave shielding effectiveness (SE) of modern window panes. In addition, it will be made sure of what is the main mechanism behind the electromagnetic shielding by investigating three different glasses reflection coefficient. In order to achieve these goals, shielding effectiveness of window panes and their components will be measured in semi-anechoic and anechoic chambers. Furthermore, these measurements will be done in near and far field conditi...

  9. Variable frequency iteration MPPT for resonant power converters

    Science.gov (United States)

    Zhang, Qian; Bataresh, Issa; Chen, Lin

    2015-06-30

    A method of maximum power point tracking (MPPT) uses an MPPT algorithm to determine a switching frequency for a resonant power converter, including initializing by setting an initial boundary frequency range that is divided into initial frequency sub-ranges bounded by initial frequencies including an initial center frequency and first and second initial bounding frequencies. A first iteration includes measuring initial powers at the initial frequencies to determine a maximum power initial frequency that is used to set a first reduced frequency search range centered or bounded by the maximum power initial frequency including at least a first additional bounding frequency. A second iteration includes calculating first and second center frequencies by averaging adjacent frequent values in the first reduced frequency search range and measuring second power values at the first and second center frequencies. The switching frequency is determined from measured power values including the second power values.

  10. Roots and Relevance

    DEFF Research Database (Denmark)

    Gumucio-Dagron, Alfonso; Tufte, Thomas

    This anthology, the result of 3 years of review of 1000+ articles, now assembles 150 authors with 200 contributions - full articles, excerpts and quotes - ranging from 1927 to 2005. The articles all have been selected upon the criteria of contributing conceptually to the field of communication fo...... Participation, 3) Power, Media and the Public Sphere, 4) Paradigms in Communication for Development, 5) Information Society & Communication Rights....... for social change. The book is organised in two parts: the first part being cronological, from 1927-1995, and the second part containing 'the contemporary debate' in communication for social change, organised in 5 sub-themes: 1) Popular Culture, Narrative and Identity, 2) Social Movements & Community...

  11. Parametric decay below the upper hybrid frequency

    Energy Technology Data Exchange (ETDEWEB)

    Albers, E; Krause, K; Schlueter, H [Bochum Univ. (Germany, F.R.). Inst. fuer Experimentalphysik 2

    1977-03-21

    Parametric decay of the upper hybrid mode is observed between the electron cyclotron frequency and its first two harmonics. The decay products are identified as electron Bernstein and ion acoustic mode. The diagnostic results confirm the relevant dispersion relations.

  12. Selective attention modulates human auditory brainstem responses: relative contributions of frequency and spatial cues.

    Directory of Open Access Journals (Sweden)

    Alexandre Lehmann

    Full Text Available Selective attention is the mechanism that allows focusing one's attention on a particular stimulus while filtering out a range of other stimuli, for instance, on a single conversation in a noisy room. Attending to one sound source rather than another changes activity in the human auditory cortex, but it is unclear whether attention to different acoustic features, such as voice pitch and speaker location, modulates subcortical activity. Studies using a dichotic listening paradigm indicated that auditory brainstem processing may be modulated by the direction of attention. We investigated whether endogenous selective attention to one of two speech signals affects amplitude and phase locking in auditory brainstem responses when the signals were either discriminable by frequency content alone, or by frequency content and spatial location. Frequency-following responses to the speech sounds were significantly modulated in both conditions. The modulation was specific to the task-relevant frequency band. The effect was stronger when both frequency and spatial information were available. Patterns of response were variable between participants, and were correlated with psychophysical discriminability of the stimuli, suggesting that the modulation was biologically relevant. Our results demonstrate that auditory brainstem responses are susceptible to efferent modulation related to behavioral goals. Furthermore they suggest that mechanisms of selective attention actively shape activity at early subcortical processing stages according to task relevance and based on frequency and spatial cues.

  13. Low-frequency noise from large wind turbines.

    Science.gov (United States)

    Møller, Henrik; Pedersen, Christian Sejer

    2011-06-01

    As wind turbines get larger, worries have emerged that the turbine noise would move down in frequency and that the low-frequency noise would cause annoyance for the neighbors. The noise emission from 48 wind turbines with nominal electric power up to 3.6 MW is analyzed and discussed. The relative amount of low-frequency noise is higher for large turbines (2.3-3.6 MW) than for small turbines (≤ 2 MW), and the difference is statistically significant. The difference can also be expressed as a downward shift of the spectrum of approximately one-third of an octave. A further shift of similar size is suggested for future turbines in the 10-MW range. Due to the air absorption, the higher low-frequency content becomes even more pronounced, when sound pressure levels in relevant neighbor distances are considered. Even when A-weighted levels are considered, a substantial part of the noise is at low frequencies, and for several of the investigated large turbines, the one-third-octave band with the highest level is at or below 250 Hz. It is thus beyond any doubt that the low-frequency part of the spectrum plays an important role in the noise at the neighbors. © 2011 Acoustical Society of America

  14. High-frequency energy in singing and speech

    Science.gov (United States)

    Monson, Brian Bruce

    While human speech and the human voice generate acoustical energy up to (and beyond) 20 kHz, the energy above approximately 5 kHz has been largely neglected. Evidence is accruing that this high-frequency energy contains perceptual information relevant to speech and voice, including percepts of quality, localization, and intelligibility. The present research was an initial step in the long-range goal of characterizing high-frequency energy in singing voice and speech, with particular regard for its perceptual role and its potential for modification during voice and speech production. In this study, a database of high-fidelity recordings of talkers was created and used for a broad acoustical analysis and general characterization of high-frequency energy, as well as specific characterization of phoneme category, voice and speech intensity level, and mode of production (speech versus singing) by high-frequency energy content. Directionality of radiation of high-frequency energy from the mouth was also examined. The recordings were used for perceptual experiments wherein listeners were asked to discriminate between speech and voice samples that differed only in high-frequency energy content. Listeners were also subjected to gender discrimination tasks, mode-of-production discrimination tasks, and transcription tasks with samples of speech and singing that contained only high-frequency content. The combination of these experiments has revealed that (1) human listeners are able to detect very subtle level changes in high-frequency energy, and (2) human listeners are able to extract significant perceptual information from high-frequency energy.

  15. Long-range correlated percolation

    International Nuclear Information System (INIS)

    Weinrib, A.

    1984-01-01

    This paper is a study of the percolation problem with long-range correlations in the site or bond occupations. An extension of the Harris criterion for the relevance of the correlations is derived for the case that the correlations decay as x/sup -a/ for large distances x. For a d the correlations are relevant if dν-2<0. Applying this criterion to the behavior that results when the correlations are relevant, we argue that the new behavior will have ν/sub long/ = 2/a. It is shown that the correlated bond percolation problem is equivalent to a q-state Potts model with quenched disorder in the limit q→1. With the use of this result, a renormalization-group study of the problem is presented, expanding in epsilon = 6-d and in delta = 4-a. In addition to the normal percolation fixed point, we find a new long-range fixed point. The crossover to this new fixed point follows the extended Harris criterion, and the fixed point has exponents ν/sub long/ = 2/a (as predicted) and eta/sub long/ = (1/11)(delta-epsilon). Finally, several results on the percolation properties of the Ising model at its critical point are shown to be in agreement with the predictions of this paper

  16. The noseleaf of Rhinolophus formosae focuses the Frequency Modulated (FM) component of the calls.

    Science.gov (United States)

    Vanderelst, Dieter; Lee, Ya-Fu; Geipel, Inga; Kalko, Elisabeth K V; Kuo, Yen-Min; Peremans, Herbert

    2013-01-01

    Bats of the family Rhinolophidae emit their echolocation calls through their nostrils and feature elaborate noseleaves shaping the directionality of the emissions. The calls of these bats consist of a long constant-frequency component preceded and/or followed by short frequency-modulated sweeps. While Rhinolophidae are known for their physiological specializations for processing the constant frequency part of the calls, previous evidence suggests that the noseleaves of these animals are tuned to the frequencies in the frequency modulated components of the calls. In this paper, we seek further support for this hypothesis by simulating the emission beam pattern of the bat Rhinolophus formosae. Filling the furrows of lancet and removing the basal lappets (i.e., two flaps on the noseleaf) we find that these conspicuous features of the noseleaf focus the emitted energy mostly for frequencies in the frequency-modulated components. Based on the assumption that this component of the call is used by the bats for ranging, we develop a qualitative model to assess the increase in performance due to the furrows and/or the lappets. The model confirms that both structures decrease the ambiguity in selecting relevant targets for ranging. The lappets and the furrows shape the emission beam for different spatial regions and frequency ranges. Therefore, we conclude that the presented evidence is in line with the hypothesis that different parts of the noseleaves of Rhinolophidae are tuned to different frequency ranges with at least some of the most conspicuous ones being tuned to the frequency modulated components of the calls-thus yielding strong evidence for the sensory importance of the component.

  17. The noseleaf of Rhinolophus formosae focuses the Frequency Modulated (FM component of the calls

    Directory of Open Access Journals (Sweden)

    Dieter eVanderelst

    2013-07-01

    Full Text Available Bats of the family Rhinolophidae emit their echolocation calls through their nostrils and feature elaborate noseleaves shaping the directionality of the emissions. The calls of these bats consist of a long constant-frequency component preceded and/or followed by short frequency-modulated sweeps. While Rhinolophidae are known for their physiological specializations for processing the constant frequency part of the calls, previous evidence suggests that the noseleaves of these animals are tuned to the frequencies in the frequency modulated components of the calls. In this paper, we seek further support for this hypothesis by simulating the emission beam pattern of the bat Rhinolophus formosae. Filling the furrows of lancet and removing the basal lappets (i.e. two flaps on the noseleaf we find that these conspicuous features of the noseleaf focus the emitted energy mostly for frequencies in the frequency-modulated components. Based on the assumption that this component of the call is used by the bats for ranging, we develop a qualitative model to assess the increase in performance due to the furrows and/or the lappets. The model confirms that both structures decrease the ambiguity in selecting relevant targets for ranging. The lappets and the furrows shape the emission beam for different spatial regions and frequency ranges. Therefore, we conclude that that the presented evidence is in line with the hypothesis that different parts of the noseleaves of Rhinolophidae are tuned to different frequency ranges with at least some of the most conspicuous ones being tuned to the frequency modulated components of the calls - thus yielding strong evidence for the sensory importance of the component.

  18. EOG feature relevance determination for microsleep detection

    OpenAIRE

    Golz Martin; Wollner Sebastian; Sommer David; Schnieder Sebastian

    2017-01-01

    Automatic relevance determination (ARD) was applied to two-channel EOG recordings for microsleep event (MSE) recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC) and logarithmic power spectral densities (PSD) averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ) was used as ARD...

  19. Is QCD relevant to nuclear physics

    International Nuclear Information System (INIS)

    Thomas, A.W.

    1985-01-01

    A review is given of recent work on baryon structure in a number of QCD-motivated models. After establishing a prima facie case that the quark model should be relevant in a consistent description of the nucleus over a wide range of momentum transfer, the author looks for experimental confirmation. The discussion includes the search for exotic states, for a six quark component of the deuteron, and an up to date report on the interpretation of the EMC effect. (Auth.)

  20. Frequency Standards and Metrology

    Science.gov (United States)

    Maleki, Lute

    2009-04-01

    Preface / Lute Maleki -- Symposium history / Jacques Vanier -- Symposium photos -- pt. I. Fundamental physics. Variation of fundamental constants from the big bang to atomic clocks: theory and observations (Invited) / V. V. Flambaum and J. C. Berengut. Alpha-dot or not: comparison of two single atom optical clocks (Invited) / T. Rosenband ... [et al.]. Variation of the fine-structure constant and laser cooling of atomic dysprosium (Invited) / N. A. Leefer ... [et al.]. Measurement of short range forces using cold atoms (Invited) / F. Pereira Dos Santos ... [et al.]. Atom interferometry experiments in fundamental physics (Invited) / S. W. Chiow ... [et al.]. Space science applications of frequency standards and metrology (Invited) / M. Tinto -- pt. II. Frequency & metrology. Quantum metrology with lattice-confined ultracold Sr atoms (Invited) / A. D. Ludlow ... [et al.]. LNE-SYRTE clock ensemble: new [symbol]Rb hyperfine frequency measurement - spectroscopy of [symbol]Hg optical clock transition (Invited) / M. Petersen ... [et al.]. Precise measurements of S-wave scattering phase shifts with a juggling atomic clock (Invited) / S. Gensemer ... [et al.]. Absolute frequency measurement of the [symbol] clock transition (Invited) / M. Chwalla ... [et al.]. The semiclassical stochastic-field/atom interaction problem (Invited) / J. Camparo. Phase and frequency noise metrology (Invited) / E. Rubiola ... [et al.]. Optical spectroscopy of atomic hydrogen for an improved determination of the Rydberg constant / J. L. Flowers ... [et al.] -- pt. III. Clock applications in space. Recent progress on the ACES mission (Invited) / L. Cacciapuoti and C. Salomon. The SAGAS mission (Invited) / P. Wolf. Small mercury microwave ion clock for navigation and radioScience (Invited) / J. D. Prestage ... [et al.]. Astro-comb: revolutionizing precision spectroscopy in astrophysics (Invited) / C. E. Kramer ... [et al.]. High frequency very long baseline interferometry: frequency standards and

  1. Radio Ranging Techniques to test Relativistic Gravitation

    OpenAIRE

    Cowsik, R.

    1999-01-01

    It is suggested that modern techniques of radio ranging when applied to study the motion of the Moon, can improve the accuracy of tests of relativistic gravitation obtained with currently operating laser ranging techniques. Other auxillary information relevant to the Solar system would also emerge from such a study.

  2. Microwave Frequency Multiplier

    Science.gov (United States)

    Velazco, J. E.

    2017-02-01

    High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing

  3. Nanoliter-droplet acoustic streaming via ultra high frequency surface acoustic waves.

    Science.gov (United States)

    Shilton, Richie J; Travagliati, Marco; Beltram, Fabio; Cecchini, Marco

    2014-08-06

    The relevant length scales in sub-nanometer amplitude surface acoustic wave-driven acoustic streaming are demonstrated. We demonstrate the absence of any physical limitations preventing the downscaling of SAW-driven internal streaming to nanoliter microreactors and beyond by extending SAW microfluidics up to operating frequencies in the GHz range. This method is applied to nanoliter scale fluid mixing. © 2014 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Tonopah Test Range - Index

    Science.gov (United States)

    Capabilities Test Operations Center Test Director Range Control Track Control Communications Tracking Radars Photos Header Facebook Twitter YouTube Flickr RSS Tonopah Test Range Top TTR_TOC Tonopah is the testing range of choice for all national security missions. Tonopah Test Range (TTR) provides research and

  5. Radio frequency system for nuclear fusion

    International Nuclear Information System (INIS)

    Kozeki, Shoichiro; Sagawa, Norimoto; Takizawa, Teruhiro

    1987-01-01

    The importance of radio frequency waves has been increasing in the area of nuclear fusion since they are indispensable for heating of plasma, etc. This report outlines radio frequency techniques used for nuclear fusion and describes the development of radio frequency systems (radio frequency plasma heating system and current drive system). Presently, in-depth studies are underway at various research institutes to achieve plasma heating by injection of radio frequency electric power. Three ranges of frequencies, ICRF (ion cyclotron range of frequency), LHRF (lower hybrid range of frequency) and ECRF (electron cyclotron range of frequency), are considered promissing for radio frequency heating. Candidate waves for plasma current driving include ECW (electron cyclotron wave), LHW (lower hybrid wave), MSW (magnetic sound wave), ICW (ion cyclotron wave) with minority component, and FW (fast wave). FW is the greatest in terms of current drive efficiency. In general, a radio frequency system for nuclear fusion consists of a radio frequency power source, transmission/matching circuit component and plasma connection component. (Nogami, K.)

  6. 47 CFR 87.475 - Frequencies.

    Science.gov (United States)

    2010-10-01

    ... with simultaneous radiotelephone channels and their associated glide path station frequency from the...) VHF omni-range (VOR) stations are to be assigned frequencies in the 112.050-117.950 MHz band (50 kHz channel spacing) and the following frequencies in the 108-112 MHz band: 108.200 108.250 108.400 108.450...

  7. Laser Spectroscopy and Frequency Combs

    International Nuclear Information System (INIS)

    Hänsch, Theodor W; Picqué, Nathalie

    2013-01-01

    The spectrum of a frequency comb, commonly generated by a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. The invention of the frequency comb technique has been motivated by precision laser spectroscopy of the simple hydrogen atom. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose. Laser combs are becoming powerful instruments for broadband molecular spectroscopy by dramatically improving the resolution and recording speed of Fourier spectrometers and by creating new opportunities for highly multiplexed nonlinear spectroscopy, such as two-photon spectroscopy or coherent Raman spectroscopy. Other emerging applications of frequency combs range from fundamental research in astronomy, chemistry, or attosecond science to telecommunications and satellite navigation

  8. Profiles of Dialogue for Relevance

    Directory of Open Access Journals (Sweden)

    Douglas Walton

    2016-12-01

    Full Text Available This paper uses argument diagrams, argumentation schemes, and some tools from formal argumentation systems developed in artificial intelligence to build a graph-theoretic model of relevance shown to be applicable (with some extensions as a practical method for helping a third party judge issues of relevance or irrelevance of an argument in real examples. Examples used to illustrate how the method works are drawn from disputes about relevance in natural language discourse, including a criminal trial and a parliamentary debate.

  9. Relevance theory: pragmatics and cognition.

    Science.gov (United States)

    Wearing, Catherine J

    2015-01-01

    Relevance Theory is a cognitively oriented theory of pragmatics, i.e., a theory of language use. It builds on the seminal work of H.P. Grice(1) to develop a pragmatic theory which is at once philosophically sensitive and empirically plausible (in both psychological and evolutionary terms). This entry reviews the central commitments and chief contributions of Relevance Theory, including its Gricean commitment to the centrality of intention-reading and inference in communication; the cognitively grounded notion of relevance which provides the mechanism for explaining pragmatic interpretation as an intention-driven, inferential process; and several key applications of the theory (lexical pragmatics, metaphor and irony, procedural meaning). Relevance Theory is an important contribution to our understanding of the pragmatics of communication. © 2014 John Wiley & Sons, Ltd.

  10. Clinical relevance in anesthesia journals

    DEFF Research Database (Denmark)

    Lauritsen, Jakob; Møller, Ann M

    2006-01-01

    The purpose of this review is to present the latest knowledge and research on the definition and distribution of clinically relevant articles in anesthesia journals. It will also discuss the importance of the chosen methodology and outcome of articles.......The purpose of this review is to present the latest knowledge and research on the definition and distribution of clinically relevant articles in anesthesia journals. It will also discuss the importance of the chosen methodology and outcome of articles....

  11. EOG feature relevance determination for microsleep detection

    Directory of Open Access Journals (Sweden)

    Golz Martin

    2017-09-01

    Full Text Available Automatic relevance determination (ARD was applied to two-channel EOG recordings for microsleep event (MSE recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC and logarithmic power spectral densities (PSD averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ was used as ARD method to show the potential of feature reduction. This is compared to support-vector machines (SVM, in which the feature reduction plays a much smaller role. Cross validation yielded mean normalised relevancies of PSD features in the range of 1.6 – 4.9 % and 1.9 – 10.4 % for horizontal and vertical EOG, respectively. MaxCC relevancies were 0.002 – 0.006 % and 0.002 – 0.06 %, respectively. This shows that PSD features of vertical EOG are indispensable, whereas MaxCC can be neglected. Mean classification accuracies were estimated at 86.6±b 1.3 % and 92.3±b 0.2 % for GRLVQ and SVM, respectively. GRLVQ permits objective feature reduction by inclusion of all processing stages, but is not as accurate as SVM.

  12. EOG feature relevance determination for microsleep detection

    Directory of Open Access Journals (Sweden)

    Golz Martin

    2017-09-01

    Full Text Available Automatic relevance determination (ARD was applied to two-channel EOG recordings for microsleep event (MSE recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC and logarithmic power spectral densities (PSD averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ was used as ARD method to show the potential of feature reduction. This is compared to support-vector machines (SVM, in which the feature reduction plays a much smaller role. Cross validation yielded mean normalised relevancies of PSD features in the range of 1.6 - 4.9 % and 1.9 - 10.4 % for horizontal and vertical EOG, respectively. MaxCC relevancies were 0.002 - 0.006 % and 0.002 - 0.06 %, respectively. This shows that PSD features of vertical EOG are indispensable, whereas MaxCC can be neglected. Mean classification accuracies were estimated at 86.6±b 1.3 % and 92.3±b 0.2 % for GRLVQ and SVM, respec-tively. GRLVQ permits objective feature reduction by inclu-sion of all processing stages, but is not as accurate as SVM.

  13. Frequency modulation drive for a piezoelectric motor

    Science.gov (United States)

    Mittas, Anthony

    2001-01-01

    A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f.sub.1 -.DELTA.x to f.sub.1 +.DELTA.y.

  14. Micronuclei Frequency in Radiation Worker

    International Nuclear Information System (INIS)

    Sudprasert, Wanwisa; Jungtanasombut, Amornrat; Pakkong, Pannee

    2009-07-01

    Full text: The purpose of this study is to determine the micronuclei (MN) frequency in peripheral blood lymphocytes of 31 individuals occupationally exposed to radiation compared to 24 controls. The effect of donor gender, age, alcoholic consumption, tea/coffee consumption and radiation burden on MN frequency was studied. The results showed that MN frequencies observed for exposed employees were significantly higher than in controls (p = 0.000). The average MN frequency in control was 39.1 ± 3.7 MN/1000 BN while those of exposed group were 60.9 ± 12.3, 61.6 ± 13.0 and 62.6 ± 11.8 MN/1000 BN for the range of accumulative doses at 0.01-3.00, 3.01-6.00 and 6.01-9.00 mSv, respectively. Moreover, MN frequency showed a positive trend with increased accumulative doses as a linear-quadratic relation (R 2 = 0.4754). No correlation of MN frequency with gender, age and alcoholic consumption could be observed in both exposed and control groups. However, the effect of tea/coffee consumption on MN frequency was clearly observed in the exposed individuals (t-test = -2.018, sig. (2-tailed) = 0.030). These results indicate that the increased MN frequency, an indicator of chromosomal aberration, is associated with occupational exposure to low doses of ionizing radiation

  15. The importance of individual frequencies of endogenous brain oscillations for auditory cognition - A short review.

    Science.gov (United States)

    Baltus, Alina; Herrmann, Christoph Siegfried

    2016-06-01

    Oscillatory EEG activity in the human brain with frequencies in the gamma range (approx. 30-80Hz) is known to be relevant for a large number of cognitive processes. Interestingly, each subject reveals an individual frequency of the auditory gamma-band response (GBR) that coincides with the peak in the auditory steady state response (ASSR). A common resonance frequency of auditory cortex seems to underlie both the individual frequency of the GBR and the peak of the ASSR. This review sheds light on the functional role of oscillatory gamma activity for auditory processing. For successful processing, the auditory system has to track changes in auditory input over time and store information about past events in memory which allows the construction of auditory objects. Recent findings support the idea of gamma oscillations being involved in the partitioning of auditory input into discrete samples to facilitate higher order processing. We review experiments that seem to suggest that inter-individual differences in the resonance frequency are behaviorally relevant for gap detection and speech processing. A possible application of these resonance frequencies for brain computer interfaces is illustrated with regard to optimized individual presentation rates for auditory input to correspond with endogenous oscillatory activity. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Direct measurements of damping rates and stability limits for low frequency MHD modes and Alfven Eigenmodes in the JET tokamak

    International Nuclear Information System (INIS)

    Fasoli, A.F.; Testa, D.; Jaun, A.; Sharapov, S.; Gormezano, C.

    2001-01-01

    The linear stability properties of global modes that can be driven by resonant energetic particles or by the bulk plasma are studied using an external excitation method based on the JET saddle coil antennas. Low toroidal mode number, stable plasma modes are driven by the saddle coils and detected by magnetic probes to measure their structure, frequency and damping rate, both in the Alfven Eigenmode (AE) frequency range and in the low frequency Magneto-Hydro-Dynamic (MHD) range. For AEs, the dominant damping mechanisms are identified for different plasma conditions of relevance for reactors. Spectra and damping rates of low frequency MHD modes that are localized at the foot of the internal transport barrier and can affect the plasma performance in advanced tokamak scenarios have been directly measured for the first time. This gives the possibility of monitoring in real time the approach to the instability boundary. (author)

  17. GHz band frequency hopping PLL-based frequency synthesizers

    Institute of Scientific and Technical Information of China (English)

    XU Yong; WANG Zhi-gong; GUAN Yu; XU Zhi-jun; QIAO Lu-feng

    2005-01-01

    In this paper we describe a full-integrated circuit containing all building blocks of a completed PLL-based synthesizer except for low pass filter(LPF).The frequency synthesizer is designed for a frequency hopping (FH) transceiver operating up to 1.5 GHz as a local oscillator. The architecture of Voltage Controlled Oscillator (VCO) is optimized to get better performance, and a phase noise of -111.85-dBc/Hz @ 1 MHz and a tuning range of 250 MHz are gained at a centre frequency of 1.35 GHz.A novel Dual-Modulus Prescaler(DMP) is designed to achieve a very low jitter and a lower power.The settling time of PLL is 80 μs while the reference frequency is 400 KHz.This monolithic frequency synthesizer is to integrate all main building blocks of PLL except for the low pass filter,with a maximum VCO output frequency of 1.5 GHz,and is fabricated with a 0.18 μm mixed signal CMOS process. Low power dissipation, low phase noise, large tuning range and fast settling time are gained in this design.

  18. Frequency noise in frequency swept fiber laser

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-01-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto......- optical modulators and forward propagating Brillouin scattering appear in the spectrum. © 2013 Optical Society of America....

  19. Ranging Behaviour of Commercial Free-Range Broiler Chickens 2: Individual Variation.

    Science.gov (United States)

    Taylor, Peta S; Hemsworth, Paul H; Groves, Peter J; Gebhardt-Henrich, Sabine G; Rault, Jean-Loup

    2017-07-20

    Little is known about broiler chicken ranging behaviour. Previous studies have monitored ranging behaviour at flock level but whether individual ranging behaviour varies within a flock is unknown. Using Radio Frequency Identification technology, we tracked 1200 individual ROSS 308 broiler chickens across four mixed sex flocks in two seasons on one commercial farm. Ranging behaviour was tracked from first day of range access (21 days of age) until 35 days of age in winter flocks and 44 days of age in summer flocks. We identified groups of chickens that differed in frequency of range visits: chickens that never accessed the range (13 to 67% of tagged chickens), low ranging chickens (15 to 44% of tagged chickens) that accounted for range visits and included chickens that used the range only once (6 to 12% of tagged chickens), and high ranging chickens (3 to 9% of tagged chickens) that accounted for 33 to 50% of all range visits. Males spent longer on the range than females in winter ( p ranging behaviour may help optimise ranging opportunities in free-range systems and is important to elucidate the potential welfare implications of ranging.

  20. Compressive laser ranging.

    Science.gov (United States)

    Babbitt, Wm Randall; Barber, Zeb W; Renner, Christoffer

    2011-12-15

    Compressive sampling has been previously proposed as a technique for sampling radar returns and determining sparse range profiles with a reduced number of measurements compared to conventional techniques. By employing modulation on both transmission and reception, compressive sensing in ranging is extended to the direct measurement of range profiles without intermediate measurement of the return waveform. This compressive ranging approach enables the use of pseudorandom binary transmit waveforms and return modulation, along with low-bandwidth optical detectors to yield high-resolution ranging information. A proof-of-concept experiment is presented. With currently available compact, off-the-shelf electronics and photonics, such as high data rate binary pattern generators and high-bandwidth digital optical modulators, compressive laser ranging can readily achieve subcentimeter resolution in a compact, lightweight package.

  1. Shippingport: A relevant decommissioning project

    International Nuclear Information System (INIS)

    Crimi, F.P.

    1988-01-01

    Because of Shippingport's low electrical power rating (72 MWe), there has been some misunderstanding on the relevancy of the Shippingport Station Decommissioning Project (SSDP) to a modern 1175 MWe commercial pressurized water reactor (PWR) power station. This paper provides a comparison of the major components of the reactor plant of the 72 MWe Shippingport Atomic Power Station and an 1175 MWe nuclear plant and the relevancy of the Shippingport decommissioning as a demonstration project for the nuclear industry. For the purpose of this comparison, Portland General Electric Company's 1175 MWe Trojan Nuclear Plant at Rainier, Oregon, has been used as the reference nuclear power plant. 2 refs., 2 figs., 1 tab

  2. Dryden Aeronautical Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — Recently redesignated to honor Dr. Hugh L. Dryden, NASA's Dryden Aeronautical Test Range (DATR) supports aerospace flight research and technology integration, space...

  3. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  4. New generation neonatal high frequency ventilators: effect of oscillatory frequency and working principles on performance.

    Science.gov (United States)

    Grazioli, Serge; Karam, Oliver; Rimensberger, Peter C

    2015-03-01

    Several new generation neonatal ventilators that incorporate conventional as well as high frequency ventilation (HFOV) have appeared on the market. Most of them offer the possibility to use HFOV in a volume-targeted mode, despite absence of any preclinical data. With a bench test, we evaluated the performances of 4 new neonatal HFOV devices and compared them to the SensorMedics HFOV device. Expiratory tidal volumes (V(T)) were measured for various ventilator settings and lung characteristics (ie, modifications of compliance and resistance of the system), to mimic several clinical conditions of pre-term and term infants. Increasing the frequency proportionally decreased the V(T) for all the ventilators, although the magnitude of the decrease was highly variable between ventilators. At 15 Hz and a pressure amplitude of 60 cm H2O, the delivered V(T) ranged from 3.5 to 5.9 mL between devices while simulating pre-term infant conditions and from 2.6 to 6.3 mL while simulating term infant conditions. Activating the volume-targeted mode in the 3 machines that offer this mode allowed the V(T) to remain constant over the range of frequencies and with changes of lung mechanical properties, for pre-term infant settings only while targeting a V(T) of 1 mL. These new generation neonatal ventilators were able to deliver adequate V(T) under pre-term infant, but not term infant respiratory system conditions. The clinical relevance of these findings will need to be determined by further studies. Copyright © 2015 by Daedalus Enterprises.

  5. Electromagnetic fields - introduction to relevant issues

    International Nuclear Information System (INIS)

    Brueggemeyer, H.; Csicsaky, M.

    1993-01-01

    This introductory paper surveys potential sources of electric magnetic, and electro-magnetic fields. Various cases are discussed to exemplify the total frequency range: nuclear magnetic resonance tomography, high-voltage transmission lines, transformer stations, effect lighting balls, military transmitters, transmitter towers of the Postal Services and other operators, mobile radiotelephone equipment, large broadcasting transmitters, radar radiation, high-frequency heat therapy. There is evidence suggesting that electric, magnetic and electro-magnetic fields may possibly represent a certain nuisance or health hazard even at field strength occuring in equipment used for every-day-life purposes, with an emphasis on their possible actions and effects in children and adolescents. The author discusses, in conclusion, the aerial equipment ordinance issued by Lower Saxony. (Uhe) [de

  6. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-01-01

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected

  7. Current-to-frequency converter

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, S W [Institute of Nuclear Research, Warsaw (Poland)

    1981-07-15

    A current-to-frequency converter covering the range from 3 x 10/sup -10/ A up to 3 x 10/sup -5/ A of the input current is described. The circuit operates with nuclear detectors featuring a high internal resistance.

  8. Low-frequency noise from large wind turbines

    DEFF Research Database (Denmark)

    Møller, Henrik; Pedersen, Christian Sejer

    2011-01-01

    As wind turbines get larger, worries have emerged that the turbine noise would move down in frequency and that the low-frequency noise would cause annoyance for the neighbors. The noise emission from 48 wind turbines with nominal electric power up to 3.6 MW is analyzed and discussed. The relative...... amount of low-frequency noise is higher for large turbines (2.3–3.6 MW) than for small turbines (≤ 2 MW), and the difference is statistically significant. The difference can also be expressed as a downward shift of the spectrum of approximately one-third of an octave. A further shift of similar size...... is suggested for future turbines in the 10-MW range. Due to the air absorption, the higher low-frequency content becomes even more pronounced, when sound pressure levels in relevant neighbor distances are considered. Even when A-weighted levels are considered, a substantial part of the noise is at low...

  9. Magnetic Frequency Response of HL-LHC Beam Screens

    Energy Technology Data Exchange (ETDEWEB)

    Morrone, M. [CERN; Martino, M. [CERN; De Maria, R. [CERN; Fitterer, M. [Fermilab; Garion, C. [CERN

    2017-10-12

    Magnetic fields used to control particle beams in accelerators are usually controlled by regulating the electrical current of the power converters. In order to minimize lifetime degradation and ultimately luminosity loss in circular colliders, current-noise is a highly critical figure of merit of power converters, in particular for magnets located in areas with high beta-function, like the High Luminosity Large Hadron Collider (HL-LHC) insertions. However, what is directly acting upon the beam is the magnetic field and not the current of the power converter, which undergoes several frequency-dependent transformations until the desired magnetic field, seen by the beam, is obtained. Beam screens are very rarely considered when assessing or specifying the noise figure of merit, but their magnetic frequency response is such that they realize relatively effective low pass filtering of the magnetic field produced by the system magnet-power converter. This work aims at filling this gap by quantifying the expected impact of different beam screen layouts for the most relevant HL-LHC insertion magnets. A welldefined post-processing technique is used to derive the frequency response of the different multipoles from multi-physics Finite Element Method (FEM) simulation results. In addition, a well approximated analytical formula for the low-frequency range of multi-layered beam screens is presented.

  10. Range Scheduling Aid (RSA)

    Science.gov (United States)

    Logan, J. R.; Pulvermacher, M. K.

    1991-01-01

    Range Scheduling Aid (RSA) is presented in the form of the viewgraphs. The following subject areas are covered: satellite control network; current and new approaches to range scheduling; MITRE tasking; RSA features; RSA display; constraint based analytic capability; RSA architecture; and RSA benefits.

  11. On Range of Skill

    DEFF Research Database (Denmark)

    Hansen, Thomas Dueholm; Miltersen, Peter Bro; Sørensen, Troels Bjerre

    2008-01-01

    size (and doubly exponential in its depth). We also provide techniques that yield concrete bounds for unbalanced game trees and apply these to estimate the Range of Skill of Tic-Tac-Toe and Heads-Up Limit Texas Hold'em Poker. In particular, we show that the Range of Skill of Tic-Tac-Toe is more than...

  12. Comparison of High, Intermediate, and Low Frequency Shock Wave Lithotripsy for Urinary Tract Stone Disease: Systematic Review and Network Meta-Analysis.

    Science.gov (United States)

    Kang, Dong Hyuk; Cho, Kang Su; Ham, Won Sik; Lee, Hyungmin; Kwon, Jong Kyou; Choi, Young Deuk; Lee, Joo Yong

    2016-01-01

    To perform a systematic review and network meta-analysis of randomized controlled trials (RCTs) to determine the optimal shock wave lithotripsy (SWL) frequency range for treating urinary stones, i.e., high-frequency (100-120 waves/minute), intermediate-frequency (80-90 waves/minute), and low-frequency (60-70 waves/minute) lithotripsy. Relevant RCTs were identified from electronic databases for meta-analysis of SWL success and complication rates. Using pairwise and network meta-analyses, comparisons were made by qualitative and quantitative syntheses. Outcome variables are provided as odds ratios (ORs) with 95% confidence intervals (CIs). Thirteen articles were included in the qualitative and quantitative synthesis using pairwise and network meta-analyses. On pairwise meta-analyses, comparable inter-study heterogeneity was observed for the success rate. On network meta-analyses, the success rates of low- (OR 2.2; 95% CI 1.5-2.6) and intermediate-frequency SWL (OR 2.5; 95% CI 1.3-4.6) were higher than high-frequency SWL. Forest plots from the network meta-analysis showed no significant differences in the success rate between low-frequency SWL versus intermediate-frequency SWL (OR 0.87; 95% CI 0.51-1.7). There were no differences in complication rate across different SWL frequency ranges. By rank-probability testing, intermediate-frequency SWL was ranked highest for success rate, followed by low-frequency and high-frequency SWL. Low-frequency SWL was also ranked highest for low complication rate, with high- and intermediate-frequency SWL ranked lower. Intermediate- and low-frequency SWL have better treatment outcomes than high-frequency SWL when considering both efficacy and complication.

  13. Dramatic lives and relevant becomings

    DEFF Research Database (Denmark)

    Henriksen, Ann-Karina; Miller, Jody

    2012-01-01

    of marginality into positions of relevance. The analysis builds on empirical data from Copenhagen, Denmark, gained through ethnographic fieldwork with the participation of 20 female informants aged 13–22. The theoretical contribution proposes viewing conflicts as multi-linear, multi-causal and non...

  14. Regularization in Matrix Relevance Learning

    NARCIS (Netherlands)

    Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael

    A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can

  15. Home range and travels

    Science.gov (United States)

    Stickel, L.F.; King, John A.

    1968-01-01

    The concept of home range was expressed by Seton (1909) in the term 'home region,' which Burr (1940, 1943) clarified with a definition of home range and exemplified in a definitive study of Peromyscus in the field. Burt pointed out the ever-changing characteristics of home-range area and the consequent absence of boundaries in the usual sense--a finding verified by investigators thereafter. In the studies summarized in this paper, sizes of home ranges of Peromyscus varied within two magnitudes, approximately from 0.1 acre to ten acres, in 34 studies conducted in a variety of habitats from the seaside dunes of Florida to the Alaskan forests. Variation in sizes of home ranges was correlated with both environmental and physiological factors; with habitat it was conspicuous, both in the same and different regions. Food supply also was related to size of home range, both seasonally and in relation to habitat. Home ranges generally were smallest in winter and largest in spring, at the onset of the breeding season. Activity and size also were affected by changes in weather. Activity was least when temperatures were low and nights were bright. Effects of rainfall were variable. Sizes varied according to sex and age; young mice remained in the parents' range until they approached maturity, when they began to travel more widely. Adult males commonly had larger home ranges than females, although there were a number of exceptions. An inverse relationship between population density and size of home range was shown in several studies and probably is the usual relationship. A basic need for activity and exploration also appeared to influence size of home range. Behavior within the home range was discussed in terms of travel patterns, travels in relation to home sites and refuges, territory, and stability of size of home range. Travels within the home range consisted of repeated use of well-worn trails to sites of food, shelter, and refuge, plus more random exploratory travels

  16. Autonomous Target Ranging Techniques

    DEFF Research Database (Denmark)

    Jørgensen, Peter Siegbjørn; Jørgensen, John Leif; Denver, Troelz

    2003-01-01

    of this telescope, a fast determination of the range to and the motion of the detected targets are important. This is needed in order to prepare the future observation strategy for each target, i.e. when is the closest approach where imaging will be optimal. In order to quickly obtain such a determination two...... ranging strategies are presented. One is an improved laser ranger with an effective range with non-cooperative targets of at least 10,000 km, demonstrated in ground tests. The accuracy of the laser ranging will be approximately 1 m. The laser ranger may furthermore be used for trajectory determination...... of nano-gravity probes, which will perform direct mass measurements of selected targets. The other is triangulation from two spacecraft. For this method it is important to distinguish between detection and tracking range, which will be different for Bering since different instruments are used...

  17. Dynamic range meter for radiofrequency amplifiers

    Directory of Open Access Journals (Sweden)

    Drozd S. S.

    2009-04-01

    Full Text Available The new measurement setup having increased on 20…30 dB the own dynamic range in comparison with the standard circuit of the dynamic range meter is offered and the rated value of an error bringing by setup in the worst case does not exceed ± 2,8 dB. The measurement setup can be applied also to determinate levels of intermodulation components average power amplifiers and powerful amplifiers of a low-frequency at replacement of the quartz filter on meeting low-frequency the LC-filter and the spectrum analyzer.

  18. Relevance of randomised controlled trials in oncology.

    Science.gov (United States)

    Tannock, Ian F; Amir, Eitan; Booth, Christopher M; Niraula, Saroj; Ocana, Alberto; Seruga, Bostjan; Templeton, Arnoud J; Vera-Badillo, Francisco

    2016-12-01

    Well-designed randomised controlled trials (RCTs) can prevent bias in the comparison of treatments and provide a sound basis for changes in clinical practice. However, the design and reporting of many RCTs can render their results of little relevance to clinical practice. In this Personal View, we discuss the limitations of RCT data and suggest some ways to improve the clinical relevance of RCTs in the everyday management of patients with cancer. RCTs should ask questions of clinical rather than commercial interest, avoid non-validated surrogate endpoints in registration trials, and have entry criteria that allow inclusion of all patients who are fit to receive treatment. Furthermore, RCTs should be reported with complete accounting of frequency and management of toxicities, and with strict guidelines to ensure freedom from bias. Premature reporting of results should be avoided. The bar for clinical benefit should be raised for drug registration, which should require publication and review of mature data from RCTs, post-marketing health outcome studies, and value-based pricing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Nanoelectromechanical systems: Nanodevice motion at microwave frequencies

    Science.gov (United States)

    Henry Huang, Xue Ming; Zorman, Christian A.; Mehregany, Mehran; Roukes, Michael L.

    2003-01-01

    It has been almost forgotten that the first computers envisaged by Charles Babbage in the early 1800s were mechanical and not electronic, but the development of high-frequency nanoelectromechanical systems is now promising a range of new applications, including sensitive mechanical charge detectors and mechanical devices for high-frequency signal processing, biological imaging and quantum measurement. Here we describe the construction of nanodevices that will operate with fundamental frequencies in the previously inaccessible microwave range (greater than 1 gigahertz). This achievement represents a significant advance in the quest for extremely high-frequency nanoelectromechanical systems.

  20. Resonance frequency analysis

    Directory of Open Access Journals (Sweden)

    Rajiv K Gupta

    2011-01-01

    Full Text Available Initial stability at the placement and development of osseointegration are two major issues for implant survival. Implant stability is a mechanical phenomenon which is related to the local bone quality and quantity, type of implant, and placement technique used. The application of a simple, clinically applicable, non-invasive test to assess implant stability and osseointegration is considered highly desirable. Resonance frequency analysis (RFA is one of such techniques which is most frequently used now days. The aim of this paper was to review and analyze critically the current available literature in the field of RFA, and to also discuss based on scientific evidence, the prognostic value of RFA to detect implants at risk of failure. A search was made using the PubMed database to find all the literature published on "Resonance frequency analysis for implant stability" till date. Articles discussed in vivo or in vitro studies comparing RFA with other methods of implant stability measurement and articles discussing its reliability were thoroughly reviewed and discussed. A limited number of clinical reports were found. Various studies have demonstrated the feasibility and predictability of the technique. However, most of these articles are based on retrospective data or uncontrolled cases. Randomized, prospective, parallel-armed longitudinal human trials are based on short-term results and long-term follow up are still scarce in this field. Nonetheless, from available literature, it may be concluded that RFA technique evaluates implant stability as a function of stiffness of the implant bone interface and is influenced by factors such as bone type, exposed implant height above the alveolar crest. Resonance frequency analysis could serve as a non-invasive diagnostic tool for detecting the implant stability of dental implants during the healing stages and in subsequent routine follow up care after treatment. Future studies, preferably randomized

  1. Low-frequency quantitative ultrasound imaging of cell death in vivo

    International Nuclear Information System (INIS)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J.; Papanicolau, Naum; Tadayyon, Hadi; Lee, Justin; Zubovits, Judit; Sadeghian, Alireza; Karshafian, Raffi; Al-Mahrouki, Azza; Giles, Anoja; Kolios, Michael C.

    2013-01-01

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r 2 = 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency, in

  2. Low-frequency quantitative ultrasound imaging of cell death in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J. [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Papanicolau, Naum; Tadayyon, Hadi [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Lee, Justin [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Zubovits, Judit [Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Sadeghian, Alireza [Department of Computer Science, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Karshafian, Raffi [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Al-Mahrouki, Azza; Giles, Anoja [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Kolios, Michael C. [Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5, Canada and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)

    2013-08-15

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r{sup 2}= 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency

  3. Frequency regulated compact screw compressors. The new solution; Drehzahlgeregelte Kompakt-Schraubenverdichter. Die neue Loesung

    Energy Technology Data Exchange (ETDEWEB)

    Juergensen, Heinz [BITZER Kuehlmaschinenbau GmbH, Sindelfingen (Germany)

    2012-07-01

    Compact screw compressors have been used for many years in liquid chilling packages for comfort air conditioners, process cooling or heat pumps with mechanical power control. Standard frequency inverters offer the possibility to adjust the performance of a conventional screw compressor, piston compressor or scroll compressor in a small range of frequency. Furthermore, frequency inverters contain a number of additional functions. This combination of existing frequency inverters and compressors - as actually offered in many cases - allows only a limited improvement of the part-load performance in the system. Due to the high cost for the frequency inverters, this combination becomes economically questionable. An integrated package of newly developed compact screw compressors and a specially developed liquid-cooled frequency inverter is required in order to come to a new level of system efficiency at part load. In addition to the increased control range of the compressor, new possibilities can be opened up in terms of application and communication. The monitoring of various values such as the compliance with the application limits for pressure and temperature and especially the early warning against exceedance facilitates a more simply implementation of a secure machine because the setting of the relevant protection functions of the integrated type-specific components already is made in the factory.

  4. Prediction ranges. Annual review

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.C.; Tharp, W.H.; Spiro, P.S.; Keng, K.; Angastiniotis, M.; Hachey, L.T.

    1988-01-01

    Prediction ranges equip the planner with one more tool for improved assessment of the outcome of a course of action. One of their major uses is in financial evaluations, where corporate policy requires the performance of uncertainty analysis for large projects. This report gives an overview of the uses of prediction ranges, with examples; and risks and uncertainties in growth, inflation, and interest and exchange rates. Prediction ranges and standard deviations of 80% and 50% probability are given for various economic indicators in Ontario, Canada, and the USA, as well as for foreign exchange rates and Ontario Hydro interest rates. An explanatory note on probability is also included. 23 tabs.

  5. Individual Ranging Behaviour Patterns in Commercial Free-Range Layers as Observed through RFID Tracking.

    Science.gov (United States)

    Larsen, Hannah; Cronin, Greg M; Gebhardt-Henrich, Sabine G; Smith, Carolynn L; Hemsworth, Paul H; Rault, Jean-Loup

    2017-03-09

    In this exploratory study, we tracked free-range laying hens on two commercial flocks with Radio Frequency Identification (RFID) technology with the aim to examine individual hen variation in range use. Three distinct outdoor zones were identified at increasing distances from the shed; the veranda [0-2.4 m], close range [2.4-11.4 m], and far range [>11.4 m]. Hens' movements between these areas were tracked using radio frequency identification technology. Most of the hens in both flocks (68.6% in Flock A, and 82.2% in Flock B) accessed the range every day during the study. Of the hens that accessed the range, most hens accessed all three zones (73.7% in Flock A, and 84.5% in Flock B). Hens spent half of their time outdoors in the veranda area. Within-individual consistency of range use (daily duration and frequency) varied considerably, and hens which were more consistent in their daily range use spent more time on the range overall ( p ranging behaviour may help elucidate the implications of ranging for laying hens.

  6. Radar network communication through sensing of frequency hopping

    Science.gov (United States)

    Dowla, Farid; Nekoogar, Faranak

    2013-05-28

    In one embodiment, a radar communication system includes a plurality of radars having a communication range and being capable of operating at a sensing frequency and a reporting frequency, wherein the reporting frequency is different than the sensing frequency, each radar is adapted for operating at the sensing frequency until an event is detected, each radar in the plurality of radars has an identification/location frequency for reporting information different from the sensing frequency, a first radar of the radars which senses the event sends a reporting frequency corresponding to its identification/location frequency when the event is detected, and all other radars in the plurality of radars switch their reporting frequencies to match the reporting frequency of the first radar upon detecting the reporting frequency switch of a radar within the communication range. In another embodiment, a method is presented for communicating information in a radar system.

  7. Auditory filters at low-frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Møller, Henrik

    2009-01-01

    -ear transfer function), the asymmetry of the auditory filter changed from steeper high-frequency slopes at 1000 Hz to steeper low-frequency slopes below 100 Hz. Increasing steepness at low-frequencies of the middle-ear high-pass filter is thought to cause this effect. The dynamic range of the auditory filter...... was found to steadily decrease with decreasing center frequency. Although the observed decrease in filter bandwidth with decreasing center frequency was only approximately monotonic, the preliminary data indicates the filter bandwidth does not stabilize around 100 Hz, e.g. it still decreases below...

  8. Antenna Pattern Range (APR)

    Data.gov (United States)

    Federal Laboratory Consortium — TheAntenna Pattern Range (APR)features a non-metallic arch with a trolley to move the transmit antenna from the horizon to zenith. At the center of the ground plane,...

  9. Atlantic Test Range (ATR)

    Data.gov (United States)

    Federal Laboratory Consortium — ATR controls fully-instrumented and integrated test ranges that provide full-service support for cradle-to-grave testing. Airspace and surface target areas are used...

  10. EV range sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ostafew, C. [Azure Dynamics Corp., Toronto, ON (Canada)

    2010-07-01

    This presentation included a sensitivity analysis of electric vehicle components on overall efficiency. The presentation provided an overview of drive cycles and discussed the major contributors to range in terms of rolling resistance; aerodynamic drag; motor efficiency; and vehicle mass. Drive cycles that were presented included: New York City Cycle (NYCC); urban dynamometer drive cycle; and US06. A summary of the findings were presented for each of the major contributors. Rolling resistance was found to have a balanced effect on each drive cycle and proportional to range. In terms of aerodynamic drive, there was a large effect on US06 range. A large effect was also found on NYCC range in terms of motor efficiency and vehicle mass. figs.

  11. Low frequency noise from large wind turbines - updated 2011; Lavfrekvent stoej fra store vindmoeller - opdateret 2011

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, H.; Sejer Pedersen, C.; Pedersen, Steffen

    2011-07-01

    The study analyzed measurements of noise from 65 wind turbines, 25 large turbines (2.3 to 3.6 MW) and 40 small ones (up to 2 MW). The large mills (2.3 to 3.6 MW) emit relatively more low frequency noise than the small ones (up to 2 MW). The difference is statistically significant for the frequency range 63-250 Hz, regardless of whether calculations are performed on all the large mills or only on new wind turbines. There are no significant differences between prototype turbines and the new mills. Because of wind noise in the measurements of the small mills, it is not possible to determine whether the difference between small and large turbines continues further down in frequency. Looking at the A-weighted sound pressure in relevant neighbor distances, the lower frequencies constitute an essential part of the noise from the large mills, and there is no doubt that the low frequency noise is both audible and annoying. When the total A-weighted sound pressure level is the same, there will on average be about 3 dB more low frequency noise from large turbines than from small ones. At large distances the noise character becomes yet more low frequency because atmospheric absorption reduces the high frequencies more than the low frequencies. Depending on the sound insulation the low frequency noise can also be annoying indoors. If the total A-weighted sound pressure level outdoors is 44 dB, the low frequency noise can be heard indoors in all the houses and for all the large turbines. The sound pressure level will in many cases exceed the indoor limit for evening night at 20 dB. (ln)

  12. The Improved Relevance Voxel Machine

    DEFF Research Database (Denmark)

    Ganz, Melanie; Sabuncu, Mert; Van Leemput, Koen

    The concept of sparse Bayesian learning has received much attention in the machine learning literature as a means of achieving parsimonious representations of features used in regression and classification. It is an important family of algorithms for sparse signal recovery and compressed sensing....... Hence in its current form it is reminiscent of a greedy forward feature selection algorithm. In this report, we aim to solve the problems of the original RVoxM algorithm in the spirit of [7] (FastRVM).We call the new algorithm Improved Relevance Voxel Machine (IRVoxM). Our contributions...... and enables basis selection from overcomplete dictionaries. One of the trailblazers of Bayesian learning is MacKay who already worked on the topic in his PhD thesis in 1992 [1]. Later on Tipping and Bishop developed the concept of sparse Bayesian learning [2, 3] and Tipping published the Relevance Vector...

  13. High-Frequency Seafloor Acoustics

    CERN Document Server

    Jackson, Darrell R

    2007-01-01

    High-Frequency Seafloor Acoustics is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. This exciting new title provides ready access to experimental data, theory, and models relevant to high-frequency seafloor acoustics and will be of interest to sonar engineers and researchers working in underwater acoustics. The physical characteristics of the seafloor affecting acoustic propagation and scattering are covered, including physical and geoacoustic properties and surface roughness. Current theories for acoustic propagation in sediments are presented along with corresponding models for reflection, scattering, and seafloor penetration. The main text is backed up by an extensive bibliography and technical appendices.

  14. Iodine frequency references for space

    International Nuclear Information System (INIS)

    Schuldt, Thilo; Braxmaier, Claus; Döringshoff, Klaus; Peters, Achim; Oswald, Markus; Johann, Ulrich

    2017-01-01

    Optical frequency references are a key element for the realization of future space missions. They are needed for missions related to tests of fundamental physics, gravitational wave detection, Earth observation and navigation and ranging. In missions such as GRACE follow-on or LISA the optical frequency reference is used as light source for high-sensitivity inter-satellite distance metrology. While cavity-based systems are current baseline e.g. for LISA, frequency stabilization on a hyperfine transition in molecular iodine near 532 nm is a promising alternative. Due to its absolute frequency, iodine standards crucially simplify the initial spacecraft acquisition procedures. Current setups fulfill the GRACE-FO and LISA frequency stability requirements and are realized near Engineering Model level. We present the current status of our developments on Elegant Breadboard (EBB) and Engineering Model (EM) level taking into account specific design criteria for space compatibility such as compactness (size iodine spectroscopy EM: 38 × 18 × 10 cm 3 ) and robustness. Both setups achieved similar frequency stabilities of ∼ 1 · 10 −14 at an integration time of 1 s and below 5 · 10 −15 at integration times between 10 s and 1000 s. Furthermore, we present an even more compact design currently developed for a sounding rocket mission with launch in 2017. (paper)

  15. Range Selection and Median

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund; Larsen, Kasper Green

    2011-01-01

    and several natural special cases thereof. The rst special case is known as range median, which arises when k is xed to b(j 􀀀 i + 1)=2c. The second case, denoted prex selection, arises when i is xed to 0. Finally, we also consider the bounded rank prex selection problem and the xed rank range......Range selection is the problem of preprocessing an input array A of n unique integers, such that given a query (i; j; k), one can report the k'th smallest integer in the subarray A[i];A[i+1]; : : : ;A[j]. In this paper we consider static data structures in the word-RAM for range selection...... selection problem. In the former, data structures must support prex selection queries under the assumption that k for some value n given at construction time, while in the latter, data structures must support range selection queries where k is xed beforehand for all queries. We prove cell probe lower bounds...

  16. String Stretching, Frequency Modulation, and Banjo Clang

    OpenAIRE

    Politzer, David

    2014-01-01

    The banjo’s floating bridge, string break angle, and flexible drumhead all contribute to substantial audio range frequency modulation. From the world of electronic music synthesis, it is known that modulating higher frequency sounds with lower acoustic frequencies leads to metallic and bell-like tone. The mechanics of the banjo does just that quite naturally, modulating fundamentals and harmonics with the motion of the bridge. In technical terms, with a floating bridge, string stretching is f...

  17. On the frequency scalings of RF guns

    International Nuclear Information System (INIS)

    Lin, L.C.; Chen, S.C.; Wurtele, J.S.

    1995-01-01

    A frequency scaling law for RF guns is derived from the normalized Vlasov-Maxwell equations. It shows that higher frequency RF guns can generate higher brightness beams under the assumption that the accelerating gradient and all beam and structure parameters are scaled with the RF frequency. Numerical simulation results using MAGIC confirm the scaling law. A discussion of the range of applicability of the law is presented. copyright 1995 American Institute of Physics

  18. Very-low-frequency magnetic plasma

    International Nuclear Information System (INIS)

    Pendry, J.B.; O'Brien, S.

    2002-01-01

    We show that a set of current-carrying wires can exhibit an effective magnetic permeability at very low frequencies of a few hertz. The resonant permeability, which is negative above the resonance frequency, arises from the oscillations of the wires driven by the applied magnetic field. We show that a large, frequency-specific and tunable effective permeability can be realized for a wide range of strengths of the applied field. (author)

  19. Popularity and Relevance of Science Education and Scientific Literacy

    DEFF Research Database (Denmark)

    Graeber, Wolfgang; Blonder, Ron; Bolte, Claus

    2008-01-01

    A consortium of researchers from 8 European nations has successfully applied to the EU commission for funding the PARSEL (Popularity and Relevance in Science Education for Scientific Literacy) project, which aims at raising the popularity and relevance of science teaching and enhancing students...... of a range of personal and social skills (including cognitive skills associated with investigatory scientific problem solving and socio-scientific decision making) and clarify the relevancy of science education for the 21st century. This symposium will introduce and discuss the project PARSEL ideas within...

  20. Online Sorted Range Reporting

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf; Greve, Mark

    2009-01-01

    is motivated by (and is a generalization of) a problem with applications in search engines: On a tree where leaves have associated rank values, report the highest ranked leaves in a given subtree. Finally, the problem studied generalizes the classic range minimum query (RMQ) problem on arrays....

  1. Substring Range Reporting

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2014-01-01

    We revisit various string indexing problems with range reporting features, namely, position-restricted substring searching, indexing substrings with gaps, and indexing substrings with intervals. We obtain the following main results. We give efficient reductions for each of the above problems...

  2. Substring Range Reporting

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2011-01-01

    We revisit various string indexing problems with range reporting features, namely, position-restricted substring searching, indexing substrings with gaps, and indexing substrings with intervals. We obtain the following main results. – We give efficient reductions for each of the above problems...

  3. Range-clustering queries

    NARCIS (Netherlands)

    Abrahamsen, M.; de Berg, M.T.; Buchin, K.A.; Mehr, M.; Mehrabi, A.D.

    2017-01-01

    In a geometric k -clustering problem the goal is to partition a set of points in R d into k subsets such that a certain cost function of the clustering is minimized. We present data structures for orthogonal range-clustering queries on a point set S : given a query box Q and an integer k>2 , compute

  4. Microdosing: Concept, application and relevance

    Directory of Open Access Journals (Sweden)

    Tushar Tewari

    2010-01-01

    Full Text Available The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an enabling effect. The lack of enabling provisions for microdosing studies in Indian regulation, despite low risk and manifest relevance for the local drug development industry, is inconsistent with the country′s aspirations to be among the leaders in pharmaceutical research.

  5. OLFAR - Orbiting low frequency antennas for radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan

    2013-01-01

    One of the last unexplored frequency ranges in radio astronomy is the frequency band below 30 MHz. New interesting astronomical science drivers for low frequency radio astronomy have emerged, ranging from studies of the astronomical dark ages, the epoch of reionization, exoplanets, to ultra-high

  6. Medium Range Forecasts Representation (and Long Range Forecasts?)

    Science.gov (United States)

    Vincendon, J.-C.

    2009-09-01

    The progress of the numerical forecasts urges us to interest us in more and more distant ranges. We thus supply more and more forecasts with term of some days. Nevertheless, precautions of use are necessary to give the most reliable and the most relevant possible information. Available in a TV bulletin or on quite other support (Internet, mobile phone), the interpretation and the representation of a medium range forecast (5 - 15 days) must be different from those of a short range forecast. Indeed, the "foresee-ability” of a meteorological phenomenon decreases gradually in the course of the ranges, it decreases all the more quickly that the phenomenon is of small scale. So, at the end of some days, the probability character of a forecast becomes very widely dominating. That is why in Meteo-France the forecasts of D+4 to D+7 are accompanied with a confidence index since around ten years. It is a figure between 1 and 5: the more we approach 5, the more the confidence in the supplied forecast is good. In the practice, an indication is supplied for period D+4 / D+5, the other one for period D+6 / D+7, every day being able to benefit from a different forecast, that is be represented in a independent way. We thus supply a global tendency over 24 hours with less and less precise symbols as the range goes away. Concrete examples will be presented. From now on two years, we also publish forecasts to D+8 / J+9, accompanied with a sign of confidence (" good reliability " or " to confirm "). These two days are grouped together on a single map because for us, the described tendency to this term is relevant on a duration about 48 hours with a spatial scale slightly superior to the synoptic scale. So, we avoid producing more than two zones of types of weather over France and we content with giving an evolution for the temperatures (still, in increase or in decline). Newspapers began to publish this information, it should soon be the case of televisions. It is particularly

  7. Essays on high frequency financial econometrics

    NARCIS (Netherlands)

    Yang, X.

    2015-01-01

    It has long been demonstrated that continuous-time methods are powerful tools in financial modeling. Yet only in recent years, their counterparts in empirical analysis—high frequency econometrics—began to emerge with the availability of intra-day data and relevant statistical tools. This

  8. AUTOMATIC FREQUENCY CONTROL SYSTEM

    Science.gov (United States)

    Hansen, C.F.; Salisbury, J.D.

    1961-01-10

    A control is described for automatically matching the frequency of a resonant cavity to that of a driving oscillator. The driving oscillator is disconnected from the cavity and a secondary oscillator is actuated in which the cavity is the frequency determining element. A low frequency is mixed with the output of the driving oscillator and the resultant lower and upper sidebands are separately derived. The frequencies of the sidebands are compared with the secondary oscillator frequency. deriving a servo control signal to adjust a tuning element in the cavity and matching the cavity frequency to that of the driving oscillator. The driving oscillator may then be connected to the cavity.

  9. Contact resistance measurement structures for high frequencies

    NARCIS (Netherlands)

    Roy, Deepu; Pijper, Ralf M.T.; Tiemeijer, Luuk F.; Wolters, Robertus A.M.

    2011-01-01

    Knowledge of the interfacial contact impedance offered by the device at its operating frequency range is crucial for accurate modelling and understanding of the device. In this article, a novel modified TLM test-structure has been devised to extract interfacial contact parameters at frequencies upto

  10. Extended Range Intercept Technology

    Science.gov (United States)

    1991-09-01

    1988). Desert bighorn ewes with lambs show a stronger response than do groups of only rams, only ewes, or mixed groups of adults (Miller and Smith...1985). While all startle events may affect desert bighorns, those occurring during the lambing period (February-April) would represent the highest...35807 U.S. Army Pueblo Depot Activity SDSTE-PU-EE Pueblo, CO 81001-5000 U.S. Army White Sands Missile Range STEWS -EL-N White Sands, NM 88002-5076

  11. ORANGE: RANGE OF BENEFITS

    OpenAIRE

    Parle Milind; Chaturvedi Dev

    2012-01-01

    No wonder that oranges are one of the most popular fruits in the world. Orange (citrus sinensis) is well known for its nutritional and medicinal properties throughout the world. From times immemorial, whole Orange plant including ripe and unripe fruits, juice, orange peels, leaves and flowers are used as a traditional medicine. Citrus sinensis belongs to the family Rutaceae. The fruit is a fleshy, indehiscent, berry that ranges widely in size from 4 cm to 12 cm. The major medicinal proper...

  12. Range Flight Safety Requirements

    Science.gov (United States)

    Loftin, Charles E.; Hudson, Sandra M.

    2018-01-01

    The purpose of this NASA Technical Standard is to provide the technical requirements for the NPR 8715.5, Range Flight Safety Program, in regards to protection of the public, the NASA workforce, and property as it pertains to risk analysis, Flight Safety Systems (FSS), and range flight operations. This standard is approved for use by NASA Headquarters and NASA Centers, including Component Facilities and Technical and Service Support Centers, and may be cited in contract, program, and other Agency documents as a technical requirement. This standard may also apply to the Jet Propulsion Laboratory or to other contractors, grant recipients, or parties to agreements to the extent specified or referenced in their contracts, grants, or agreements, when these organizations conduct or participate in missions that involve range flight operations as defined by NPR 8715.5.1.2.2 In this standard, all mandatory actions (i.e., requirements) are denoted by statements containing the term “shall.”1.3 TailoringTailoring of this standard for application to a specific program or project shall be formally documented as part of program or project requirements and approved by the responsible Technical Authority in accordance with NPR 8715.3, NASA General Safety Program Requirements.

  13. Static electromagnetic frequency changers

    CERN Document Server

    Rozhanskii, L L

    1963-01-01

    Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

  14. Superconducting Radio-Frequency Cavities

    Science.gov (United States)

    Padamsee, Hasan S.

    2014-10-01

    Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

  15. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  16. DDC Descriptor Frequencies.

    Science.gov (United States)

    Klingbiel, Paul H.; Jacobs, Charles R.

    This report summarizes the frequency of use of the 7144 descriptors used for indexing technical reports in the Defense Documentation Center (DDC) collection. The descriptors are arranged alphabetically in the first section and by frequency in the second section. The frequency data cover about 427,000 AD documents spanning the interval from March…

  17. Improved real-time dynamics from imaginary frequency lattice simulations

    Directory of Open Access Journals (Sweden)

    Pawlowski Jan M.

    2018-01-01

    Full Text Available The computation of real-time properties, such as transport coefficients or bound state spectra of strongly interacting quantum fields in thermal equilibrium is a pressing matter. Since the sign problem prevents a direct evaluation of these quantities, lattice data needs to be analytically continued from the Euclidean domain of the simulation to Minkowski time, in general an ill-posed inverse problem. Here we report on a novel approach to improve the determination of real-time information in the form of spectral functions by setting up a simulation prescription in imaginary frequencies. By carefully distinguishing between initial conditions and quantum dynamics one obtains access to correlation functions also outside the conventional Matsubara frequencies. In particular the range between ω0 and ω1 = 2πT, which is most relevant for the inverse problem may be more highly resolved. In combination with the fact that in imaginary frequencies the kernel of the inverse problem is not an exponential but only a rational function we observe significant improvements in the reconstruction of spectral functions, demonstrated in a simple 0+1 dimensional scalar field theory toy model.

  18. Improved real-time dynamics from imaginary frequency lattice simulations

    Science.gov (United States)

    Pawlowski, Jan M.; Rothkopf, Alexander

    2018-03-01

    The computation of real-time properties, such as transport coefficients or bound state spectra of strongly interacting quantum fields in thermal equilibrium is a pressing matter. Since the sign problem prevents a direct evaluation of these quantities, lattice data needs to be analytically continued from the Euclidean domain of the simulation to Minkowski time, in general an ill-posed inverse problem. Here we report on a novel approach to improve the determination of real-time information in the form of spectral functions by setting up a simulation prescription in imaginary frequencies. By carefully distinguishing between initial conditions and quantum dynamics one obtains access to correlation functions also outside the conventional Matsubara frequencies. In particular the range between ω0 and ω1 = 2πT, which is most relevant for the inverse problem may be more highly resolved. In combination with the fact that in imaginary frequencies the kernel of the inverse problem is not an exponential but only a rational function we observe significant improvements in the reconstruction of spectral functions, demonstrated in a simple 0+1 dimensional scalar field theory toy model.

  19. Other relevant numerical modelling papers

    International Nuclear Information System (INIS)

    Chartier, M.

    1989-01-01

    The ocean modelling is a rapidly evolving science and a large number of results have been published. Several categories of papers are of particular interest for this review: the papers published by the international atomic institutions, such as the NEA (for the CRESP or Subseabed Programs), the IAEA (for example the Safety Series, the Technical Report Series or the TECDOC), and the ICRP, and the papers concerned by more fundamental research, which are published in specific scientific literature. This paper aims to list some of the most relevant publications for the CRESP purposes. It means by no way to be exhaustive, but informative on the incontestable progress recently achieved in that field. One should note that some of these papers are so recent that their final version has not yet been published

  20. Industrial relevance of thermophilic Archaea.

    Science.gov (United States)

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

    The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite intensive investigations, our knowledge of the structure-function relationships of their enzymes is still limited. Information concerning the molecular properties of their enzymes and genes has to be obtained to be able to understand the mechanisms that are responsible for catalytic activity and stability at the boiling point of water.

  1. The Relevance of Hegel's Logic

    Directory of Open Access Journals (Sweden)

    John W Burbidge

    2007-12-01

    Full Text Available Hegel defines his Logic as the science that thinks about thinking.nbsp; But when we interpret that work as outlining what happens when we reason we are vulnerable to Fregersquo;s charge of psychologism.nbsp; I use Hegelrsquo;s tripartite distinction among understanding, dialectical and speculative reason as operations of pure thought to suggest how thinking can work with objective concepts.nbsp; In the last analysis, however, our ability to move from the subjective contingency of representations and ideas to the pure concepts we think develops from mechanical memory, which separates sign from sense so hat we can focus simply on the latter.nbsp; By becoming aware of the connections that underlie our thinking processes we may be able to both move beyond the abstractions of symbolic logic and clarify what informal logicians call relevance.

  2. Long-range antigravity

    Energy Technology Data Exchange (ETDEWEB)

    Macrae, K.I.; Riegert, R.J. (Maryland Univ., College Park (USA). Center for Theoretical Physics)

    1984-10-01

    We consider a theory in which fermionic matter interacts via long-range scalar, vector and tensor fields. In order not to be in conflict with experiment, the scalar and vector couplings for a given fermion must be equal, as is natural in a dimensionally reduced model. Assuming that the Sun is not approximately neutral with respect to these new scalar-vector charges, and if the couplings saturate the experimental bounds, then their strength can be comparable to that of gravity. Scalar-vector fields of this strength can compensate for a solar quadrupole moment contribution to Mercury's anomalous perihelion precession.

  3. Long-range antigravity

    International Nuclear Information System (INIS)

    Macrae, K.I.; Riegert, R.J.

    1984-01-01

    We consider a theory in which fermionic matter interacts via long-range scalar, vector and tensor fields. In order not to be in conflict with experiment, the scalar and vector couplings for a given fermion must be equal, as is natural in a dimensionally reduced model. Assuming that the Sun is not approximately neutral with respect to these new scalar-vector charges, and if the couplings saturate the experimental bounds, then their strength can be comparable to that of gravity. Scalar-vector fields of this strength can compensate for a solar quadrupole moment contribution to Mercury's anomalous perihelion precession. (orig.)

  4. Static and low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    Thommesen, G.; Tynes, T.

    1994-01-01

    The biological effects of exposure to low frequency electric and magnetic fields are reviewed with the objective of summarizing effects directly relevant to considerations of the health and safety of exposed people. Static and low frequency electric and magnetic fields may elicit biological reactions. Whether exposure to such fields may affect human health at field strengths present in everyday or occupational life is still unsettled. There is unsufficient knowledge to establish any dose concept relevant to health risk. 196 refs., 6 tabs

  5. Range Process Simulation Tool

    Science.gov (United States)

    Phillips, Dave; Haas, William; Barth, Tim; Benjamin, Perakath; Graul, Michael; Bagatourova, Olga

    2005-01-01

    Range Process Simulation Tool (RPST) is a computer program that assists managers in rapidly predicting and quantitatively assessing the operational effects of proposed technological additions to, and/or upgrades of, complex facilities and engineering systems such as the Eastern Test Range. Originally designed for application to space transportation systems, RPST is also suitable for assessing effects of proposed changes in industrial facilities and large organizations. RPST follows a model-based approach that includes finite-capacity schedule analysis and discrete-event process simulation. A component-based, scalable, open architecture makes RPST easily and rapidly tailorable for diverse applications. Specific RPST functions include: (1) definition of analysis objectives and performance metrics; (2) selection of process templates from a processtemplate library; (3) configuration of process models for detailed simulation and schedule analysis; (4) design of operations- analysis experiments; (5) schedule and simulation-based process analysis; and (6) optimization of performance by use of genetic algorithms and simulated annealing. The main benefits afforded by RPST are provision of information that can be used to reduce costs of operation and maintenance, and the capability for affordable, accurate, and reliable prediction and exploration of the consequences of many alternative proposed decisions.

  6. Dynamic modulation of epileptic high frequency oscillations by the phase of slower cortical rhythms.

    Science.gov (United States)

    Ibrahim, George M; Wong, Simeon M; Anderson, Ryan A; Singh-Cadieux, Gabrielle; Akiyama, Tomoyuki; Ochi, Ayako; Otsubo, Hiroshi; Okanishi, Tohru; Valiante, Taufik A; Donner, Elizabeth; Rutka, James T; Snead, O Carter; Doesburg, Sam M

    2014-01-01

    Pathological high frequency oscillations (pHFOs) have been proposed to be robust markers of epileptic cortex. Oscillatory activity below this frequency range has been shown to be modulated by phase of lower frequency oscillations. Here, we tested the hypothesis that dynamic cross-frequency interactions involving pHFOs are concentrated within the epileptogenic cortex. Intracranial electroencephalographic recordings from 17 children with medically-intractable epilepsy secondary to focal cortical dysplasia were obtained. A time-resolved analysis was performed to determine topographic concentrations and dynamic changes in cross-frequency amplitude-to-phase coupling (CFC). CFC between pHFOs and the phase of theta and alpha rhythms was found to be significantly elevated in the seizure-onset zone compared to non-epileptic regions (pfrequency oscillations at which pHFO amplitudes were maximal was inconsistent at seizure initiation, yet consistently at the trough of the low frequency rhythm at seizure termination. Amplitudes of pHFOs were most significantly modulated by the phase of alpha-band oscillations (p<0.01). These results suggest that increased CFC between pHFO amplitude and alpha phase may constitute a marker of epileptogenic brain areas and may be relevant for understanding seizure dynamics. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Compact frequency-modulation Q-switched single-frequency fiber laser at 1083 nm

    International Nuclear Information System (INIS)

    Zhang, Yuanfei; Feng, Zhouming; Xu, Shanhui; Mo, Shupei; Yang, Changsheng; Li, Can; Gan, Jiulin; Chen, Dongdan; Yang, Zhongmin

    2015-01-01

    A compact frequency-modulation Q-switched single-frequency fiber laser is demonstrated at 1083 nm. The short linear resonant cavity consists of a 12 mm long homemade Yb 3+ -doped phosphate fiber and a pair of fiber Bragg gratings (FBGs) in which the Q-switching and the frequency excursion is achieved by a tensile-induced period modulation. Over 375 MHz frequency-tuning range is achieved with a modulation frequency varying from tens to hundreds of kilohertz. The highest peak power of the output pulse reaching 6.93 W at the repetition rate of 10 kHz is obtained. (paper)

  8. Calculation of projected ranges

    International Nuclear Information System (INIS)

    Biersack, J.P.

    1980-09-01

    The concept of multiple scattering is reconsidered for obtaining the directional spreading of ion motion as a function of energy loss. From this the mean projection of each pathlength element of the ion trajectory is derived which - upon summation or integration - leads to the desired mean projected range. In special cases, the calculation can be carried out analytically, otherwise a simple general algorithm is derived which is suitable even for the smallest programmable calculators. Necessary input for the present treatment consists only of generally accessable stopping power and straggling formulas. The procedure does not rely on scattering cross sections, e.g. power potential or f(t 1 sup(/) 2 ) approximations. The present approach lends itself easily to include electronic straggling or to treat composed target materials, or even to account for the so-called time integral. (orig.)

  9. Vygotsky's Crisis: Argument, context, relevance.

    Science.gov (United States)

    Hyman, Ludmila

    2012-06-01

    Vygotsky's The Historical Significance of the Crisis in Psychology (1926-1927) is an important text in the history and philosophy of psychology that has only become available to scholars in 1982 in Russian, and in 1997 in English. The goal of this paper is to introduce Vygotsky's conception of psychology to a wider audience. I argue that Vygotsky's argument about the "crisis" in psychology and its resolution can be fully understood only in the context of his social and political thinking. Vygotsky shared the enthusiasm, widespread among Russian leftist intelligentsia in the 1920s, that Soviet society had launched an unprecedented social experiment: The socialist revolution opened the way for establishing social conditions that would let the individual flourish. For Vygotsky, this meant that "a new man" of the future would become "the first and only species in biology that would create itself." He envisioned psychology as a science that would serve this humanist teleology. I propose that The Crisis is relevant today insofar as it helps us define a fundamental problem: How can we systematically account for the development of knowledge in psychology? I evaluate how Vygotsky addresses this problem as a historian of the crisis. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Relevance of equilibrium in multifragmentation

    International Nuclear Information System (INIS)

    Furuta, Takuya; Ono, Akira

    2009-01-01

    The relevance of equilibrium in a multifragmentation reaction of very central 40 Ca + 40 Ca collisions at 35 MeV/nucleon is investigated by using simulations of antisymmetrized molecular dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time t in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble that well reproduces the reaction ensemble at each reaction time t for the investigated period 80≤t≤300 fm/c. However, there are some other observables that show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables

  11. ANALISYS OF FRACTIONAL-N FREQUENCY SYNTHESIZERS

    Directory of Open Access Journals (Sweden)

    Boris I. Shakhtarin

    2018-01-01

    Full Text Available Modern information and control systems cannot be imagined without synchronization subsystems. These are the basic elements that provide tracking of the frequency and phase of reference and information signals, the evaluation of information parameters, and the synthesis of reference and clock signals. Frequency synthesizers (FS are widely used due to the high speed of frequency setting, a wide range of frequency grids and minimal phase noise in the operating frequency range. Since with the mass appearance of specialized microprocessors and with the improvement of automatic design systems, the feasibility and repeatability of products has become simpler, digital FS are increasingly being used. The most widely used are FS with a frequency divider on digital elements, which serves to convert the signal of a reference oscillator and a controlled generator. For FS using a divisor with an integer division factor in the feedback loop, there are a number of limitations, such as the lower frequency of the FS and the frequency step of the FS. To solve this problem, divisors with fractional-variable division factors in the feedback loop are used, which allow to obtain the required range and the grid frequency step of the FS. The methods of improving the quality of spectral and dynamic characteristics of digital synthesizers in a given band of frequency detuning are analyzed. The principles of the FS operation with a divisor with a fractionalvariable fission coefficient are described, and structural schemes are given. The results of imitation simulation in the Simulink system of the software package MATLAB of frequency synthesizers with a divisor with a fractional-variable fission factor implemented in various ways are presented, and a comparative analysis of the spectral characteristics of the obtained models is carried out. 

  12. Long-time data storage: relevant time scales

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    2011-01-01

    Dynamic processes relevant for long-time storage of information about human kind are discussed, ranging from biological and geological processes to the lifecycle of stars and the expansion of the universe. Major results are that life will end ultimately and the remaining time that the earth is

  13. Relevance of Programs for Emotionally Disturbed Youth in Other Lands

    Science.gov (United States)

    David, Henry P.

    1970-01-01

    A survey of current trends was conducted in more than 40 countries. Focus was on the organization of services and their relevance for evolving practices in the United States. Apparent was a willingness to experiment with administrative and therapeutic roles. Ideological differences are important determinants of the organization, range, and quality…

  14. Breakfast frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Damsgaard, Mogens Trab

    2016-01-01

    OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary...... (n 3054) from a random sample of forty-one schools. RESULTS: Nearly one-quarter of the adolescents had low breakfast frequency. Low breakfast frequency was associated with low family functioning measured by three dimensions. The OR (95 % CI) of low breakfast frequency was 1·81 (1·40, 2......·33) for adolescents who reported no close relations to parents, 2·28 (1·61, 3·22) for adolescents who reported low level of quality of family communication and 2·09 (1·39, 3·15) for adolescents who reported low level of family support. Joint effect analyses suggested that the odds of low breakfast frequency among...

  15. Environmental Assessment (EA) for the Comprehensive Range Plan (CRP), Melrose Air Force Range (AFR), New Mexico

    Science.gov (United States)

    2011-07-01

    intensity, frequency, and duration. Sound is created by acoustic energy, which produces minute pressure waves that travel through a medium (like air...concave plains associated with playa lake basins. Slope ranges from zero to 1 percent. Olton Loams – Consist of very deep, well-drained, moderately slow...gently sloping plains and upper side slopes of playas and draws. Slopes range from zero to 5 percent. 3.5.2.2 Water Resources Surface Water – The most

  16. Statistical significance versus clinical relevance.

    Science.gov (United States)

    van Rijn, Marieke H C; Bech, Anneke; Bouyer, Jean; van den Brand, Jan A J G

    2017-04-01

    In March this year, the American Statistical Association (ASA) posted a statement on the correct use of P-values, in response to a growing concern that the P-value is commonly misused and misinterpreted. We aim to translate these warnings given by the ASA into a language more easily understood by clinicians and researchers without a deep background in statistics. Moreover, we intend to illustrate the limitations of P-values, even when used and interpreted correctly, and bring more attention to the clinical relevance of study findings using two recently reported studies as examples. We argue that P-values are often misinterpreted. A common mistake is saying that P < 0.05 means that the null hypothesis is false, and P ≥0.05 means that the null hypothesis is true. The correct interpretation of a P-value of 0.05 is that if the null hypothesis were indeed true, a similar or more extreme result would occur 5% of the times upon repeating the study in a similar sample. In other words, the P-value informs about the likelihood of the data given the null hypothesis and not the other way around. A possible alternative related to the P-value is the confidence interval (CI). It provides more information on the magnitude of an effect and the imprecision with which that effect was estimated. However, there is no magic bullet to replace P-values and stop erroneous interpretation of scientific results. Scientists and readers alike should make themselves familiar with the correct, nuanced interpretation of statistical tests, P-values and CIs. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  17. Indoor measurements of sound at low frequencies

    DEFF Research Database (Denmark)

    Pedersen, Steffen; Møller, Henrik; Persson-Waye, Kerstin

    2006-01-01

    Due to standing waves, the sound pressure level within a room may vary as much as 20-30 dB with low-frequency tonal noise, somewhat less with noise bands. For assessment of annoyance from low-frequency noise it is relevant to measure a level close to the highest level of the room, rather than a r...

  18. How Metastrategic Considerations Influence the Selection of Frequency Estimation Strategies

    Science.gov (United States)

    Brown, Norman R.

    2008-01-01

    Prior research indicates that enumeration-based frequency estimation strategies become increasingly common as memory for relevant event instances improves and that moderate levels of context memory are associated with moderate rates of enumeration [Brown, N. R. (1995). Estimation strategies and the judgment of event frequency. Journal of…

  19. Bayesian Frequency Domain Identification of LTI Systems with OBFs kernels

    NARCIS (Netherlands)

    Darwish, M.A.H.; Lataire, J.P.G.; Tóth, R.

    2017-01-01

    Regularised Frequency Response Function (FRF) estimation based on Gaussian process regression formulated directly in the frequency-domain has been introduced recently The underlying approach largely depends on the utilised kernel function, which encodes the relevant prior knowledge on the system

  20. Diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference

    Energy Technology Data Exchange (ETDEWEB)

    Ren Cheng; Zhang Shulian, E-mail: ren-c06@mails.tsinghua.edu.c [State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China)

    2009-08-07

    The diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference is presented. The gain medium used is a microchip 2 mm in thickness for miniaturized and integrated design. Two quarter-wave plates are placed into the laser cavity and the intra-cavity birefringence produces two orthogonally linearly polarized modes. The rotation of one of the two quarter-wave plates introduces a controlled and variable cavity birefringence which causes a variable frequency difference between the two orthogonally polarized modes. The frequency difference can be tuned through the whole cavity free spectral range. The obtained frequency difference ranges from 14 MHz to 1.5 GHz. The variation of the beat frequency over a period of 10 min is less than 10 kHz. The lock-in between modes is not found. Experimental results are presented, which match well with the theoretical analysis based on Jones matrices.

  1. Report to Congress on Sustainable Ranges, 2013

    Science.gov (United States)

    2013-04-01

    SPECTRUM The growing prevalence of wireless technology and its demand for additional frequency conflicts with the DoD’s requirement to train for...HE R Beaver Training Area US UT ARNG 657 0 0 0 N N Y N N N N N N N N Beckley City Police Range US WV ARNG 2 0 0 0 N N N N Y N N N N N N Beech Fork

  2. Frequency Response Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    Etingov, Pavel V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kosterev, Dmitry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dai, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

  3. Ecological principles relevant to nuclear war

    International Nuclear Information System (INIS)

    Hutchinson, T.C.; Cropper, W.P. Jr.; Grover, H.D.

    1985-01-01

    The ecological principles outlined are very basic ones; the authors anticipate a readership trained in a broad range of disciplines, including those unfamiliar with the academic discipline of ecology. The authors include substantial discussion on ecophysiology (i.e., the responses of organisms to their environment) because this is relevant to the new understanding of the potential climatic consequences of nuclear war. In particular, the physiological sensitivity of organisms to reduced levels of light and temperature are a key part of the analysis of the potential ecological effects and agricultural effects of nuclear war. Much of the ecological analysis has been organized around major biological units called biomes. The authors describe the biome concept and discuss some of the environmental-climatic factors that are believed to control biome distribution. Emphasis is given to plants because of their controlling influence on ecosystem functions through their role as primary producers. Future reports are needed to address more fully the potential effects on animals. Much more research needs to be done on both plant and animal responses to the types of perturbations possible for the aftermath of a nuclear war. Another important element for analysis of the potential ecological consequences of nuclear war concerns recovery processes. As the post-nuclear war environmental extremes ameliorate, ecological communities in devastated regions would begin to reorganize. It is not possible to predict the course of such a succession precisely, but some principles concerning post-perturbation replacement (such as seed banks and germination), relevant successional patterns, and organism strategies are discussed

  4. Thermochemical data for environmentally-relevant elements

    International Nuclear Information System (INIS)

    Markich, S.J.; Brown, P.L.

    1999-01-01

    This study provides an extensive stability constant (log K) database suitable for calculating the speciation of selected environmentally-relevant elements (H, Na, K, Ca, Mg, Fe, Mn, U, Al Pb, Zn, Cu and cd) in an aqueous system, where a model fulvic acid (comprising aspartic, citric, malonic, salicylic and tricarballylic acids) is used to simulate metal binding by dissolved organic material Stability constants for inorganic metal complexes and minerals were selected primarily from critical literature complications and/or reviews. In contrast, few critically evaluated data were available for metal complexes with aspartic, citric, malonic, salicylic and tricarballylic acids. Consequently, data from original research articles were carefully evaluated and compiled as part of the study, following defined selection criteria. to meet the objective of compiling a comprehensive and reliable database of stability constants, all relevant equilibria and species, ranging from simple binary metal complexes to more complex ternary and even quaternary, metal complexes were included where possible in addition to the selection of stability constants from empirical sources, estimates of stability constants were performed when this could be done reliably, based on the unified theory of metal ion complexation and/or linear tree energy relationships The stability constants are given as common logarithms (logo) in the form required by the HARPHRQ geochemical code and refer to the standard state, i.e 298.15 K (25 deg C), 10 5 Pa (1 atm) and, for all species, infinite dilution (ionic strength = 0 mol L -1 ). In addition to the compilation of stability constant data, an overview is given of geochemical speciation modelling in aqueous systems and available conceptual models of metal binding by humic substances. (authors)

  5. Does relevance matter in academic policy research?

    DEFF Research Database (Denmark)

    Dredge, Dianne

    2015-01-01

    A reflection on whether relevance matters in tourism policy research. A debate among tourism scholars.......A reflection on whether relevance matters in tourism policy research. A debate among tourism scholars....

  6. Frequency-specific modulation of population-level frequency tuning in human auditory cortex

    Directory of Open Access Journals (Sweden)

    Roberts Larry E

    2009-01-01

    Full Text Available Abstract Background Under natural circumstances, attention plays an important role in extracting relevant auditory signals from simultaneously present, irrelevant noises. Excitatory and inhibitory neural activity, enhanced by attentional processes, seems to sharpen frequency tuning, contributing to improved auditory performance especially in noisy environments. In the present study, we investigated auditory magnetic fields in humans that were evoked by pure tones embedded in band-eliminated noises during two different stimulus sequencing conditions (constant vs. random under auditory focused attention by means of magnetoencephalography (MEG. Results In total, we used identical auditory stimuli between conditions, but presented them in a different order, thereby manipulating the neural processing and the auditory performance of the listeners. Constant stimulus sequencing blocks were characterized by the simultaneous presentation of pure tones of identical frequency with band-eliminated noises, whereas random sequencing blocks were characterized by the simultaneous presentation of pure tones of random frequencies and band-eliminated noises. We demonstrated that auditory evoked neural responses were larger in the constant sequencing compared to the random sequencing condition, particularly when the simultaneously presented noises contained narrow stop-bands. Conclusion The present study confirmed that population-level frequency tuning in human auditory cortex can be sharpened in a frequency-specific manner. This frequency-specific sharpening may contribute to improved auditory performance during detection and processing of relevant sound inputs characterized by specific frequency distributions in noisy environments.

  7. Long range trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Allen, P. W.; Jessup, E. A.; White, R. E. [Air Resources Field Research Office, Las Vegas, Nevada (United States)

    1967-07-01

    A single air molecule can have a trajectory that can be described with a line, but most meteorologists use single lines to represent the trajectories of air parcels. A single line trajectory has the disadvantage that it is a categorical description of position. Like categorized forecasts it provides no qualification, and no provision for dispersion in case the parcel contains two or more molecules which may take vastly different paths. Diffusion technology has amply demonstrated that an initial aerosol cloud or volume of gas in the atmosphere not only grows larger, but sometimes divides into puffs, each having a different path or swath. Yet, the average meteorologist, faced with the problem of predicting the future motion of a cloud, usually falls back on the line trajectory approach with the explanation that he had no better tool for long range application. In his more rational moments, he may use some arbitrary device to spread his cloud with distance. One such technique has been to separate the trajectory into two or more trajectories, spaced about the endpoint of the original trajectory after a short period of travel, repeating this every so often like a chain reaction. This has the obvious disadvantage of involving a large amount of labor without much assurance of improved accuracy. Another approach is to draw a circle about the trajectory endpoint, to represent either diffusion or error. The problem then is to know what radius to give the circle and also whether to call it diffusion or error. Meteorologists at the Nevada Test Site (NTS) are asked frequently to provide advice which involves trajectory technology, such as prediction of an aerosol cloud path, reconstruction of the motion of a volume of air, indication of the dilution, and the possible trajectory prediction error over great distances. Therefore, we set out, nearly three years ago, to provide some statistical knowledge about the status of our trajectory technology. This report contains some of the

  8. Observational study of generation conditions of substorm-associated low-frequency AKR emissions

    Directory of Open Access Journals (Sweden)

    A. Olsson

    2004-11-01

    Full Text Available It has lately been shown that low-frequency bursts of auroral kilometric radiation (AKR are nearly exclusively associated with substorm expansion phases. Here we study low-frequency AKR using Polar PWI and Interball POLRAD instruments to constrain its possible generation mechanisms. We find that there are more low-frequency AKR emission events during wintertime and equinoxes than during summertime. The dot-AKR emission radial distance range coincides well with the region where the deepest density cavities are seen statistically during Kp>2. We suggest that the dot-AKR emissions originate in the deepest density cavities during substorm onsets. The mechanism for generating dot-AKR is possibly strong Alfvén waves entering the cavity from the magnetosphere and changing their character to more inertial, which causes the Alfvén wave associated parallel electric field to increase. This field may locally accelerate electrons inside the cavity enough to produce low-frequency AKR emission. We use Interball IESP low-frequency wave data to verify that in about half of the cases the dot-AKR is accompanied by low-frequency wave activity containing a magnetic component, i.e. probably inertial Alfvén waves. Because of the observational geometry, this result is consistent with the idea that inertial Alfvén waves might always be present in the source region when dot-AKR is generated. The paper illustrates once more the importance of radio emissions as a powerful remote diagnostic tool of auroral processes, which is not only relevant for the Earth's magnetosphere but may be relevant in the future in studying extrasolar planets.

  9. Frequency-dependent ultrasound-induced transformation in E. coli.

    Science.gov (United States)

    Deeks, Jeremy; Windmill, James; Agbeze-Onuma, Maduka; Kalin, Robert M; Argondizza, Peter; Knapp, Charles W

    2014-12-01

    Ultrasound-enhanced gene transfer (UEGT) is continuing to gain interest across many disciplines; however, very few studies investigate UEGT efficiency across a range of frequencies. Using a variable frequency generator, UEGT was tested in E. coli at six ultrasonic frequencies. Results indicate frequency can significantly influence UEGT efficiency positively and negatively. A frequency of 61 kHz improved UEGT efficiency by ~70 % higher, but 99 kHz impeded UEGT to an extent worse than no ultrasound exposure. The other four frequencies (26, 133, 174, and 190 kHz) enhanced transformation compared to no ultrasound, but efficiencies did not vary. The influence of frequency on UEGT efficiency was observed across a range of operating frequencies. It is plausible that frequency-dependent dynamics of mechanical and chemical energies released during cavitational-bubble collapse (CBC) are responsible for observed UEGT efficiencies.

  10. Spectrum Management Guidelines for National and Service Test and Training Ranges

    Science.gov (United States)

    2017-07-12

    Frequency Management Group RCC 700-17 SPECTRUM MANAGEMENT GUIDELINES FOR NATIONAL AND SERVICE TEST AND TRAINING RANGES DISTRIBUTION...left blank. DOCUMENT 700-01 SPECTRUM MANAGEMENT GUIDELINES FOR NATIONAL AND SERVICE TEST AND TRAINING RANGES July 2017...Prepared by RANGE COMMANDERS COUNCIL FREQUENCY MANAGEMENT GROUP Published by Secretariat Range Commanders Council U.S. Army White

  11. Science and the struggle for relevance

    NARCIS (Netherlands)

    Hessels, L.K.|info:eu-repo/dai/nl/304832863

    2010-01-01

    This thesis deals with struggles for relevance of university researchers, their efforts to make their work correspond with ruling standards of relevance and to influence these standards. Its general research question is: How to understand changes in the struggle for relevance of Dutch academic

  12. The Personal Relevance of the Social Studies.

    Science.gov (United States)

    VanSickle, Ronald L.

    1990-01-01

    Conceptualizes a personal-relevance framework derived from Ronald L. VanSickle's five areas of life integrated with four general motivating goals from Abraham Maslow's hierarchy of needs and Richard and Patricia Schmuck's social motivation theory. Illustrates ways to apply the personal relevance framework to make social studies more relevant to…

  13. The Development of Relevance in Information Retrieval

    Directory of Open Access Journals (Sweden)

    Mu-hsuan Huang

    1997-12-01

    Full Text Available This article attempts to investigate the notion of relevance in information retrieval. It discusses various definitions for relevance from historical viewpoints and the characteristics of relevance judgments. Also, it introduces empirical results of important related researches.[Article content in Chinese

  14. Ranging Behaviour of Commercial Free-Range Broiler Chickens 1: Factors Related to Flock Variability.

    Science.gov (United States)

    Taylor, Peta S; Hemsworth, Paul H; Groves, Peter J; Gebhardt-Henrich, Sabine G; Rault, Jean-Loup

    2017-07-20

    Little is known about the ranging behaviour of chickens. Understanding ranging behaviour is required to improve management and shed and range design to ensure optimal ranging opportunities. Using Radio Frequency Identification technology, we tracked 300 individual broiler chickens in each of four mixed sex ROSS 308 flocks on one commercial farm across two seasons. Ranging behaviour was tracked from the first day of range access (21 days of age) until 35 days of age in winter and 44 days of age in summer. Range use was higher than previously reported from scan sampling studies. More chickens accessed the range in summer (81%) than winter (32%; p range use was greater in summer flocks (4.4 ± 0.1 visits for a total of 26.3 ± 0.8 min/day) than winter flocks (3.2 ± 0.2 visits for a total of 7.9 ± 1.0 min/day). Seasonal differences were only marginally explained by weather conditions and may reflect the reduction in range exposure between seasons (number of days, hours per day, and time of day). Specific times of the day ( p ranging and external factors that may explain ranging preferences.

  15. Electrothermal frequency reference

    NARCIS (Netherlands)

    Makinwa, K.A.A.; Kashmiri, S.M.

    2011-01-01

    An electrothermal frequency-locked loop (EFLL) circuit is described. This EFLL circuit includes an oscillator in a feedback loop. A drive circuit in the EFLL circuit generates a first signal having a fundamental frequency, and an electrothermal filter (ETF) in the EFLL circuit provides a second

  16. Low frequency noise study.

    Science.gov (United States)

    2007-04-01

    This report documents a study to investigate human response to the low-frequency : content of aviation noise, or low-frequency noise (LFN). The study comprised field : measurements and laboratory studies. The major findings were: : 1. Start-of-takeof...

  17. Single frequency intracavity SRO

    DEFF Research Database (Denmark)

    Abitan, Haim; Buchhave, Preben

    2000-01-01

    Summary form only given. A single resonance optical parametric oscillator (SRO) is inserted intracavity to a CW high power, single frequency, and ring Nd:YVO4 laser. We obtain a stable single frequency CW SRO with output at 1.7-1.9 μm (idler) and a resonating signal at 2.3-2.6 μm. The behavior...

  18. Fast fundamental frequency estimation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

    2017-01-01

    Modelling signals as being periodic is common in many applications. Such periodic signals can be represented by a weighted sum of sinusoids with frequencies being an integer multiple of the fundamental frequency. Due to its widespread use, numerous methods have been proposed to estimate the funda...

  19. Frequency control modelling - basics

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul Ejnar; Zeni, Lorenzo

    2016-01-01

    The purpose of this report is to provide an introduction on how the system balance in an island system can be maintained by controlling the frequency. The power balance differential equation, which is fundamental in understanding the effect on the system frequency of the unbalance between...

  20. Spatial Cognition and Range Use in Free-Range Laying Hens.

    Science.gov (United States)

    Campbell, Dana L M; Talk, Andrew C; Loh, Ziyang A; Dyall, Tim R; Lee, Caroline

    2018-02-08

    Radio-frequency identification tracking shows individual free-range laying hens vary in range use, with some never going outdoors. The range is typically more environmentally complex, requiring navigation to return to the indoor resources. Outdoor-preferring hens may have improved spatial abilities compared to indoor-preferring hens. Experiment 1 tested 32 adult ISA Brown hens in a T-maze learning task that showed exclusively-indoor birds were slowest to reach the learning success criterion ( p 0.05), the age that coincided with the onset of lay. Enriched birds that were faster to learn the maze task showed more range visits in the first 4 weeks of range access. Enriched and non-enriched birds showed no differences in telencephalon or hippocampal volume ( p > 0.05). Fear may reduce spatial abilities but further testing with more pen replicates per early rearing treatments would improve our understanding of the relationship between spatial cognitive abilities and range use.

  1. Bootstrapping agency: How control-relevant information affects motivation.

    Science.gov (United States)

    Karsh, Noam; Eitam, Baruch; Mark, Ilya; Higgins, E Tory

    2016-10-01

    How does information about one's control over the environment (e.g., having an own-action effect) influence motivation? The control-based response selection framework was proposed to predict and explain such findings. Its key tenant is that control relevant information modulates both the frequency and speed of responses by determining whether a perceptual event is an outcome of one's actions or not. To test this framework empirically, the current study examines whether and how temporal and spatial contiguity/predictability-previously established as being important for one's sense of agency-modulate motivation from control. In 5 experiments, participants responded to a cue, potentially triggering a perceptual effect. Temporal (Experiments 1a-c) and spatial (Experiments 2a and b) contiguity/predictability between actions and their potential effects were experimentally manipulated. The influence of these control-relevant factors was measured, both indirectly (through their effect on explicit judgments of agency) and directly on response time and response frequency. The pattern of results was highly consistent with the control-based response selection framework in suggesting that control relevant information reliably modulates the impact of "having an effect" on different levels of action selection. We discuss the implications of this study for the notion of motivation from control and for the empirical work on the sense of agency. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  2. Students' perceptions of the relevance of mathematics in engineering

    Science.gov (United States)

    Flegg, Jennifer; Mallet, Dann; Lupton, Mandy

    2012-09-01

    In this article, we report on the findings of an exploratory study into the experience of students as they learn first year engineering mathematics. Here we define engineering as the application of mathematics and sciences to the building and design of projects for the use of society [M. Kirschenman and B. Brenner, Education for Civil Engineering: A Profession of Practice, Leader. Manag. Eng. 10 (2010), p. 54]. Qualitative and quantitative data on students' views of the relevance of their mathematics study to their engineering studies and future careers in engineering was collected. The students described using a range of mathematics techniques (mathematics skills developed, mathematics concepts applied to engineering and skills developed relevant for engineering) for various usages (as a subject of study, a tool for other subjects or a tool for real world problems). We found a number of themes relating to the design of engineering mathematics curriculum emerged from the data. These included the relevance of mathematics within different engineering majors, the relevance of mathematics to future studies, the relevance of learning mathematical rigour and the effectiveness of problem-solving tasks in conveying the relevance of mathematics more effectively than other forms of assessment. We make recommendations for the design of engineering mathematics curriculum based on our findings.

  3. Nostalgia's place among self-relevant emotions.

    Science.gov (United States)

    van Tilburg, Wijnand A P; Wildschut, Tim; Sedikides, Constantine

    2017-07-24

    How is nostalgia positioned among self-relevant emotions? We tested, in six studies, which self-relevant emotions are perceived as most similar versus least similar to nostalgia, and what underlies these similarities/differences. We used multidimensional scaling to chart the perceived similarities/differences among self-relevant emotions, resulting in two-dimensional models. The results were revealing. Nostalgia is positioned among self-relevant emotions characterised by positive valence, an approach orientation, and low arousal. Nostalgia most resembles pride and self-compassion, and least resembles embarrassment and shame. Our research pioneered the integration of nostalgia among self-relevant emotions.

  4. Digital instantaneous frequency measurement technique utilising high-speed ADC’s and FPGA’s

    CSIR Research Space (South Africa)

    Herselman, PL

    2006-02-27

    Full Text Available This paper presents the Digital Instantaneous Frequency Measurement (DIFM) technique, which can measure the carrier frequency of a received waveform within a fraction of a microsecond. The resulting frequency range, resolution and accuracy...

  5. Loads as a Resource: Frequency Responsive Demand

    Energy Technology Data Exchange (ETDEWEB)

    Kalsi, Karanjit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lian, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Marinovici, Laurentiu D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhang, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moya, Christian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-10-08

    Frequency control plays an important role in preserving the power balance of a multi-machine power system. Generators modify their power output when a non-zero frequency deviation is presented in order to restore power balance across the network. However, with plans for large-scale penetration of renewable energy resources, performing primary frequency control using only supply-side resources becomes not only prohibitively expensive, but also technically difficult. Frequency control from the demand side or load control presents a novel and viable way for providing the desired frequency response. Loads can measure frequency locally and change their power consumption after a non-zero frequency deviation is presented in order to achieve power balance between generation and consumption. The specific objectives of this project are to: •Provide a framework to facilitate large-scale deployment of frequency responsive end-use devices •Systematically design decentralized frequency-based load control strategies for enhanced stability performance •Ensure applicability over wide range of operating conditions while accounting for unpredictable end-use behavior and physical device constraints •Test and validate control strategy using large-scale simulations and field demonstrations •Create a level-playing field for smart grid assets with conventional generators

  6. Relationship between welfare and individual ranging behaviour in commercial free-range laying hens.

    Science.gov (United States)

    Larsen, H; Hemsworth, P H; Cronin, G M; Gebhardt-Henrich, S G; Smith, C L; Rault, J-L

    2018-01-24

    Laying hens housed in free-range systems have access to an outdoor range, and individual hens within a flock differ in their ranging behaviour. Whether there is a link between ranging and laying hen welfare remains unclear. We analysed the relationships between ranging by individual hens on a commercial free-range layer farm and behavioural, physiological and health measures of animal welfare. We hypothesised that hens that access the range more will be (1) less fearful in general and in response to novelty and humans, (2) have better health in terms of physical body condition and (3) have a reduced physiological stress response to behavioural tests of fear and health assessments than hens that use the range less. Using radio frequency identification tracking across two flocks, we recorded individual hens' frequency, duration and consistency of ranging. We also assessed how far hens ventured into the range based on three zones: 0 to 2.4, 2.4 to 11.4 or >11.4 m from the shed. We assessed hen welfare using a variety of measures including: tonic immobility, open field, novel object, human approach, and human avoidance (HAV) behavioural tests; stress-induced plasma corticosterone response and faecal glucocorticoid metabolites; live weight, comb colour, and beak, plumage, footpad, and keel bone condition. Range use was positively correlated with plasma corticosterone response, faecal glucocorticoid metabolites, and greater flight distance during HAV. Hens that used the range more, moved towards rather than away from the novel object more often than hens that ranged less. Distance ranged from the shed was significantly associated with comb colour and beak condition, in that hens with darker combs and more intact beaks ranged further. Overall the findings suggest that there is no strong link between outdoor range usage and laying hen welfare. Alternatively, it may be that hens that differed in their ranging behaviour showed few differences in measures of welfare because

  7. Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial

    Directory of Open Access Journals (Sweden)

    Riaz U. Ahmed

    2014-11-01

    Full Text Available This letter presents the possibility of energy scavenging (ES utilizing the physics of acousto-elastic metamaterial (AEMM at low frequencies (<∼3KHz. It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester, simultaneously. AEMM’s are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ∼3 KHz, maximum power in the micro Watts (∼35µW range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ∼10µW – ∼90µW between 0.2 KHz and 1.5 KHz acoustic frequencies.

  8. Saturation of subjective reward magnitude as a function of current and pulse frequency.

    Science.gov (United States)

    Simmons, J M; Gallistel, C R

    1994-02-01

    In rats with electrodes in the medial forebrain bundle, the upper portion of the function relating the experienced magnitude of the reward to pulse frequency was determined at currents ranging from 100 to 1,000 microA. The pulse frequency required to produce an asymptotic level of reward was inversely proportional to current except at the lowest currents and highest pulse frequencies. At a given current, the subjective reward magnitude functions decelerated to an asymptote over an interval in which the pulse frequency doubled or tripled. The asymptotic level of reward was approximately constant for currents between 200 and 1,000 microA but declined substantially at currents at or below 100 microA and pulse frequencies at or above 250 to 400 pulses per second. The results are consistent with the hypothesis that the magnitude of the experienced reward depends only on the number of action potentials generated by the train of pulses in the bundle of reward-relevant axons.

  9. Low-frequency ultrasound increases non-viral gene transfer to the mouse lung.

    Science.gov (United States)

    Xenariou, Stefania; Liang, Hai-Dong; Griesenbach, Uta; Zhu, Jie; Farley, Raymond; Somerton, Lucinda; Singh, Charanjit; Jeffery, Peter K; Scheule, Ronald K; Cheng, Seng H; Geddes, Duncan M; Blomley, Martin; Alton, Eric W F W

    2010-01-01

    The aim of the study was to assess if low-frequency ultrasound (US), in the range of 30-35 kHz, increases non-viral gene transfer to the mouse lung. US is greatly attenuated in the lung due to large energy losses at the air/tissue interfaces. The advantages of low-frequency US, compared with high-frequency US are: (i) increased cavitation (responsible for the formation of transient pores in the cell membrane) and (ii) reduced energy losses during lung penetration. Cationic lipid GL67/plasmid DNA (pDNA), polyethylenimine (PEI)/pDNA and naked pDNA were delivered via intranasal instillation and the animals were then exposed to US (sonoporation) at 0.07 or 0.1 MPa for 10 min. Under these conditions, US did not enhance GL67 or PEI-mediated transfection. It did, however, increase naked pDNA gene transfer by approximately 4 folds. Importantly, this was achieved in the absence of microbubbles, which are crucial for the commonly used high-frequency (1 MHz) sonoporation but may not be able to withstand nebulization in a clinically relevant setup. Lung hemorrhage was also assessed and shown to increase with US pressure in a dose-dependent manner. We have thus, established that low-frequency US can enhance lung gene transfer with naked pDNA and this enhancement is more effective than the previously reported 1 MHz US.

  10. Long distance measurement with a femtosecond laser based frequency comb

    Science.gov (United States)

    Bhattacharya, N.; Cui, M.; Zeitouny, M. G.; Urbach, H. P.; van den Berg, S. A.

    2017-11-01

    Recent advances in the field of ultra-short pulse lasers have led to the development of reliable sources of carrier envelope phase stabilized femtosecond pulses. The pulse train generated by such a source has a frequency spectrum that consists of discrete, regularly spaced lines known as a frequency comb. In this case both the frequency repetition and the carrier-envelope-offset frequency are referenced to a frequency standard, like an atomic clock. As a result the accuracy of the frequency standard is transferred to the optical domain, with the frequency comb as transfer oscillator. These unique properties allow the frequency comb to be applied as a versatile tool, not only for time and frequency metrology, but also in fundamental physics, high-precision spectroscopy, and laser noise characterization. The pulse-to-pulse phase relationship of the light emitted by the frequency comb has opened up new directions for long range highly accurate distance measurement.

  11. Frequency Adaptability of Harmonics Controllers for Grid-Interfaced Converters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2017-01-01

    sensitivity of the most popular harmonic controllers for grid-interfaced converters. The frequency adaptability of these harmonic controllers is evaluated in the presence of a variable grid frequency within a specified reasonable range, e.g., +-1% of the nominal grid frequency (50 Hz). Solutions...

  12. Relevance of tidal heating on large TNOs

    Science.gov (United States)

    Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry

    2018-03-01

    We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100‧s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

  13. Human error theory: relevance to nurse management.

    Science.gov (United States)

    Armitage, Gerry

    2009-03-01

    Describe, discuss and critically appraise human error theory and consider its relevance for nurse managers. Healthcare errors are a persistent threat to patient safety. Effective risk management and clinical governance depends on understanding the nature of error. This paper draws upon a wide literature from published works, largely from the field of cognitive psychology and human factors. Although the content of this paper is pertinent to any healthcare professional; it is written primarily for nurse managers. Error is inevitable. Causation is often attributed to individuals, yet causation in complex environments such as healthcare is predominantly multi-factorial. Individual performance is affected by the tendency to develop prepacked solutions and attention deficits, which can in turn be related to local conditions and systems or latent failures. Blame is often inappropriate. Defences should be constructed in the light of these considerations and to promote error wisdom and organizational resilience. Managing and learning from error is seen as a priority in the British National Health Service (NHS), this can be better achieved with an understanding of the roots, nature and consequences of error. Such an understanding can provide a helpful framework for a range of risk management activities.

  14. Time and frequency applications.

    Science.gov (United States)

    Hellwig, H

    1993-01-01

    An overview is given of the capabilities of atomic clocks and quartz crystal oscillators in terms of available precision of time and frequency signals. The generation, comparison, and dissemination of time and frequency is then discussed. The principal focus is to survey uses of time and frequency in navigation, communication, and science. The examples given include the Global Positioning System, a satellite-based global navigation system, and general and dedicated communication networks, as well as experiments in general relativity and radioastronomy. The number of atomic clocks and crystal oscillators that are in actual use worldwide is estimated.

  15. Characterizing the attenuation of coaxial and rectangular microwave-frequency waveguides at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kurpiers, Philipp; Walter, Theodore; Magnard, Paul; Salathe, Yves; Wallraff, Andreas [ETH Zuerich, Department of Physics, Zuerich (Switzerland)

    2017-12-15

    Low-loss waveguides are required for quantum communication at distances beyond the chip-scale for any low-temperature solid-state implementation of quantum information processors. We measure and analyze the attenuation constant of commercially available microwave-frequency waveguides down to millikelvin temperatures and single photon levels. More specifically, we characterize the frequency-dependent loss of a range of coaxial and rectangular microwave waveguides down to 0.005 dB/m using a resonant-cavity technique. We study the loss tangent and relative permittivity of commonly used dielectric waveguide materials by measurements of the internal quality factors and their comparison with established loss models. The results of our characterization are relevant for accurately predicting the signal levels at the input of cryogenic devices, for reducing the loss in any detection chain, and for estimating the heat load induced by signal dissipation in cryogenic systems. (orig.)

  16. Spatial filtering velocimeter for vehicle navigation with extended measurement range

    Science.gov (United States)

    He, Xin; Zhou, Jian; Nie, Xiaoming; Long, Xingwu

    2015-05-01

    The idea of using spatial filtering velocimeter is proposed to provide accurate velocity information for vehicle autonomous navigation system. The presented spatial filtering velocimeter is based on a CMOS linear image sensor. The limited frame rate restricts high speed measurement of the vehicle. To extend measurement range of the velocimeter, a method of frequency shifting is put forward. Theoretical analysis shows that the frequency of output signal can be reduced and the measurement range can be doubled by this method when the shifting direction is set the same with that of image velocity. The approach of fast Fourier transform (FFT) is employed to obtain the power spectra of the spatially filtered signals. Because of limited frequency resolution of FFT, a frequency spectrum correction algorithm, called energy centrobaric correction, is used to improve the frequency resolution. The correction accuracy energy centrobaric correction is analyzed. Experiments are carried out to measure the moving surface of a conveyor belt. The experimental results show that the maximum measurable velocity is about 800deg/s without frequency shifting, 1600deg/s with frequency shifting, when the frame rate of the image is about 8117 Hz. Therefore, the measurement range is doubled by the method of frequency shifting. Furthermore, experiments were carried out to measure the vehicle velocity simultaneously using both the designed SFV and a laser Doppler velocimeter (LDV). The measurement results of the presented SFV are coincident with that of the LDV, but with bigger fluctuation. Therefore, it has the potential of application to vehicular autonomous navigation.

  17. Inertial-range spectrum of whistler turbulence

    Directory of Open Access Journals (Sweden)

    Y. Narita

    2010-02-01

    Full Text Available We develop a theoretical model of an inertial-range energy spectrum for homogeneous whistler turbulence. The theory is a generalization of the Iroshnikov-Kraichnan concept of the inertial-range magnetohydrodynamic turbulence. In the model the dispersion relation is used to derive scaling laws for whistler waves at highly oblique propagation with respect to the mean magnetic field. The model predicts an energy spectrum for such whistler waves with a spectral index −2.5 in the perpendicular component of the wave vector and thus provides an interpretation about recent discoveries of the second inertial-range of magnetic energy spectra at high frequencies in the solar wind.

  18. Frequency adjustable MEMS vibration energy harvester

    Science.gov (United States)

    Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

    2016-10-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

  19. Frequency adjustable MEMS vibration energy harvester

    International Nuclear Information System (INIS)

    Podder, P; Constantinou, P; Roy, S; Amann, A

    2016-01-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)

  20. Frequency and Relevance of Acute Peritraumatic Pulmonary Thrombus Diagnosed by Computed Tomographic Imaging in Combat Casualties

    Science.gov (United States)

    2013-08-01

    Paso , Texas; The Norman M. Rich Department of Surgery (J.B.L., T.E.R.), Uniformed Services University of the Health Sciences, Bethesda, Maryland...mechanism made up the majority of patients diagnosed with APPT (n = 59 of 66, 89%), followed by gunshot wound (n = 6, 9%) and motor vehicle collision (n = 2...1%). When looking at injury mechanism, 13% of patients injured as a result of explosion, 3% as a result of gunshot wound, and 2%as a result of motor