WorldWideScience

Sample records for wider frequency range

  1. Inversion of spheroid particle size distribution in wider size range and aspect ratio range

    Directory of Open Access Journals (Sweden)

    Tang Hong

    2013-01-01

    Full Text Available The non-spherical particle sizing is very important in the aerosol science, and it can be determined by the light extinction measurement. This paper studies the effect of relationship of the size range and aspect ratio range on the inversion of spheroid particle size distribution by the dependent mode algorithm. The T matrix method and the geometric optics approximation method are used to calculate the extinction efficiency of the spheroids with different size range and aspect ratio range, and the inversion of spheroid particle size distribution in these different ranges is conducted. Numerical simulation indicates that a fairly reasonable representation of the spheroid particle size distribution can be obtained when the size range and aspect ratio range are suitably chosen.

  2. HBIM and augmented information: towards a wider user community of image and range-based reconstructions

    Directory of Open Access Journals (Sweden)

    L. Barazzetti

    2015-08-01

    Full Text Available This paper describes a procedure for the generation of a detailed HBIM which is then turned into a model for mobile apps based on augmented and virtual reality. Starting from laser point clouds, photogrammetric data and additional information, a geometric reconstruction with a high level of detail can be carried out by considering the basic requirements of BIM projects (parametric modelling, object relations, attributes. The work aims at demonstrating that a complex HBIM can be managed in portable devices to extract useful information not only for expert operators, but also towards a wider user community interested in cultural tourism.

  3. Colour-variable birds have broader ranges, wider niches and are less likely to be threatened.

    Science.gov (United States)

    Delhey, K; Smith, J; Peters, A

    2013-07-01

    Coloration fulfils a variety of adaptive functions in animals. Colour variability, both between and within species, can be caused by different colours being favoured for different functions and in different environments. Thus, species with highly variable coloration may have greater potential to persist in new and changing environments. As a consequence, such colour-variable species may be more able to adapt, colonize new areas and niches, occupy larger ranges, speciate more readily and in general be less vulnerable to environmental change and extinction. These predictions have been supported by comparative analyses on amphibians and reptiles. However, as coloration in ectotherms plays a key role in thermoregulation, it is unclear whether these results can be generalized to endotherms, such as birds and mammals. Here, we test the hypothesis that more colour-variable endotherms occupy larger ranges/niches and are less vulnerable to the threat of extinction by focussing on colour variation in Australian parrots and passerine birds. As predicted, colour variability was correlated with range size (parrots and passerines) and niche breadth (dietary heterogeneity, parrots only). These relationships support the predicted link between colour variability and adaptability, whereby range size and niche breadth may be a cause of colour variability or vice versa. Irrespective, and as predicted, colour variability was lower in threatened species, even after statistically controlling for other confounding variables. Hence, our study supports the hypothesis that colour-variable species in general are more resilient to environmental change. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  4. Analysis and Implementation of Nonlinear Transducer Response over a Wider Response Range

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    Sheroz Khan

    2008-03-01

    Full Text Available In today’s automation systems transducers are making core elements in the instruments and the circuits used for measurement, control and industrial applications. The task of a transducer is to reproduce a physical quantity as an electrical signal which with the help of conditioning circuits, is transformed into a form that suits a corresponding ADC requirement before a digital equivalent output of the required physical quantity is produced. In the most ideal cases a digital quantity is a true replica of the physical quantity when the transducer has got a linear response. However, in most of the cases the transducers characteristics are nonlinear, and hence at very points along the whole range of the transducer characteristics, the corresponding digital output is an exact replica of the concerned physical parameter. This work is about how a physical read more accurately in the case of nonlinear sensor characteristics, and then a microcontroller is programmed with the same technique while reading from an input over the entire range. The data of the microcontroller reading shows very closely matched with the actual sensors response. Further, the reading error is considerably reduced to within 10 % of the actual physical which shows the utility of the technique in very sensitive applications.

  5. Disease Prevention in the Age of Convergence - the Need for a Wider, Long Ranging and Collaborative Vision

    Directory of Open Access Journals (Sweden)

    Susan L. Prescott

    2014-01-01

    Full Text Available It is time to bring our imagination, creativity and passion to the fore in solving the global challenges of our age. Our global health crisis and the pandemic of noncommunicable diseases (NCDs is clearly rooted in complex modern societal and environmental changes, many of which have effects on developing immune and metabolic responses. It is intimately related to wider environmental challenges. And it is unsurprising that many NCDs share similar risk factors and that many are associated with a rising predisposition for inflammation. Allergy is one of the earliest signs of environmental impact on these biological pathways, and may also offer an early barometer to assess the effects of early interventions. There is dawning awareness of how changing microbial diversity, nutritional patterns, sedentary indoor behaviours and modern pollutants adversely affect early metabolic and immune development, but still much to understand the complexity of these interactions. Even when we do harness the science and technology, these will not provide solutions unless we also address the wider social, cultural and economic determinants of health - addressing the interconnections between human health and the health of our environment. Now more than ever, we need a wider vision and a greater sense of collective responsibility. We need long-range approaches that aim for life long benefits of a ‘healthier start to life’, and stronger cross-sectoral collaborations to prevent disease. We need to give both our hearts and our minds to solving these global issues.

  6. Wider Shoes for Wider Feet?

    Science.gov (United States)

    Meyer, Mary C.

    2006-01-01

    From a very young age, shoes for boys tend to be wider than shoes for girls. Is this because boys have wider feet, or because it is assumed that girls are willing to sacrifice comfort for fashion, even in elementary school? To assess the former, a statistician measures kids' feet. (Contains 2 tables and 3 figures.)

  7. Hemicellulose block copolymers made from woods for wide-range directed self-assembly lithography enabling wider range of applicable patterning size

    Science.gov (United States)

    Morita, Kazuyo; Yamamoto, Kimiko

    2017-03-01

    Xylan, one of hemicellulose family, block copolymer was newly developed for wide-range directed self-assembly lithography (DSA). Xylan is higher hydrophilic material because of having many hydroxy groups in one molecule. It means that xylan block copolymer has a possibility of high-chi block copolymer. Generally, DSA is focused on microphase separation for smaller size with high-chi block copolymer and not well known for larger size. In this study, xylan block copolymer was confirmed enabling wider range of patterning size, from smaller size to larger size. The key of xylan block copolymer is a new molecular structure of block copolymer and sugar chain control technology. Sugar content is the important parameter for not only micro-phase separation property but also line edge roughness (LER) and defects. Based on the sugar control technology, wide-range (hp 8.3nm to 26nm L/S and CD 10nm to 51nm hole) DSA patterning was demonstrated. Additionally it was confirmed that xylan block copolymer is suitable for sequential infiltration synthesis (SIS) process.

  8. GIARPS@TNG: GIANO-B and HARPS-N together for a wider wavelength range spectroscopy

    Science.gov (United States)

    Claudi, R.; Benatti, S.; Carleo, I.; Ghedina, A.; Guerra, J.; Micela, G.; Molinari, E.; Oliva, E.; Rainer, M.; Tozzi, A.; Baffa, C.; Baruffolo, A.; Buchschacher, N.; Cecconi, M.; Cosentino, R.; Fantinel, D.; Fini, L.; Ghinassi, F.; Giani, E.; Gonzalez, E.; Gonzalez, M.; Gratton, R.; Harutyunyan, A.; Hernandez, N.; Lodi, M.; Malavolta, L.; Maldonado, J.; Origlia, L.; Sanna, N.; Sanjuan, J.; Scuderi, S.; Seemann, U.; Sozzetti, A.; Perez Ventura, H.; Hernandez Diaz, M.; Galli, A.; Gonzalez, C.; Riverol, L.; Riverol, C.

    2017-08-01

    Since 2012, thanks to the installation of the high-resolution echelle spectrograph in the optical range HARPS-N, the Italian telescope TNG (La Palma) became one of the key facilities for the study of the extrasolar planets. In 2014 TNG also offered GIANO to the scientific community, providing a near-infrared (NIR) cross-dispersed echelle spectroscopy covering 0.97-2.45μm at a resolution of 50000. GIANO, although designed for direct light-feed from the telescope at the Nasmyth-B focus, was provisionally mounted on the rotating building and connected via fibers to only available interface at the Nasmyth-A focal plane. The synergy between these two instruments is particularly appealing for a wide range of science cases, especially for the search of exoplanets around young and active stars and the characterisation of their atmosphere. Through the funding scheme "WOW" (a Way to Others Worlds), the Italian National Institute for Astrophysics (INAF) proposed to position GIANO at the focal station for which it was originally designed and the simultaneous use of these spectrographs with the aim to achieve high-resolution spectroscopy in a wide wavelength range (0.383-2.45μm) obtained in a single exposure, giving rise to the project called GIARPS (GIANO-B & HARPS-N). Because of its characteristics, GIARPS can be considered the first and unique worldwide instrument providing not only high resolution in a large wavelength band, but also a high-precision radial velocity measurement both in the visible and in the NIR arm, since in the next future GIANO-B will be equipped with gas absorption cells.

  9. Active laser ranging with frequency transfer using frequency comb

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongyuan; Wei, Haoyun; Yang, Honglei; Li, Yan, E-mail: liyan@mail.tsinghua.edu.cn [State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China)

    2016-05-02

    A comb-based active laser ranging scheme is proposed for enhanced distance resolution and a common time standard for the entire system. Three frequency combs with different repetition rates are used as light sources at the two ends where the distance is measured. Pulse positions are determined through asynchronous optical sampling and type II second harmonic generation. Results show that the system achieves a maximum residual of 379.6 nm and a standard deviation of 92.9 nm with 2000 averages over 23.6 m. Moreover, as for the frequency transfer, an atom clock and an adjustable signal generator, synchronized to the atom clock, are used as time standards for the two ends to appraise the frequency deviation introduced by the proposed system. The system achieves a residual fractional deviation of 1.3 × 10{sup −16} for 1 s, allowing precise frequency transfer between the two clocks at the two ends.

  10. Frequency ranges and attenuation of macroseismic effects

    Science.gov (United States)

    Tosi, Patrizia; De Rubeis, Valerio; Sbarra, Paola

    2017-09-01

    Macroseismic intensity is assessed on the basis of the effects caused by an earthquake. These effects reflect the expression of both the intensity and frequency of the ground motion, thus complicating prediction equation modelling. Here we analysed data of several macroseismic transitory effects caused by recent Italian earthquakes in order to study their attenuation as a function of magnitude and hypocentral distance and to obtain a specific prediction equation, of simple functional form, that could be applied to each of the effects under analysis. We found that the different attenuation behaviours could be clearly defined by the values of the specially formulated magnitude-distance scaling ratio (S), thus allowing to group the effects on the basis of the S value. The oscillation of hanging objects and liquids, together with the feeling of dizziness, were separated from most other variables, such as the effects of the earthquake on small objects, china and windows, which were caused by a vibration of higher frequency. Besides, the greater value of S, associated with the perception of the seismic sound, explained the peculiarity of this phenomenon. As a result, we recognized the frequency range associated with each effect through comparisons with the ground motion prediction equations and, in particular, with the 5 per cent damped horizontal response spectra. Here we show the importance of appropriately selecting the diagnostic elements to be used for intensity assessment in order to improve the correlation with ground motion.

  11. 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.

  12. Discrete-time model reduction in limited frequency ranges

    Science.gov (United States)

    Horta, Lucas G.; Juang, Jer-Nan; Longman, Richard W.

    1991-01-01

    A mathematical formulation for model reduction of discrete time systems such that the reduced order model represents the system in a particular frequency range is discussed. The algorithm transforms the full order system into balanced coordinates using frequency weighted discrete controllability and observability grammians. In this form a criterion is derived to guide truncation of states based on their contribution to the frequency range of interest. Minimization of the criterion is accomplished without need for numerical optimization. Balancing requires the computation of discrete frequency weighted grammians. Close form solutions for the computation of frequency weighted grammians are developed. Numerical examples are discussed to demonstrate the algorithm.

  13. Energy based correlation criteria in the mid-frequency range

    Science.gov (United States)

    Biedermann, J.; Winter, R.; Wandel, M.; Böswald, M.

    2017-07-01

    Aircraft structures are characterized by their lightweight design. As such, they are prone to vibrations. Numerical models based on the Finite Element Method often show significant deviations when the mid-frequency range is considered, where strong interaction between vibrations and acoustics is present. Model validation based on experimental modal data is often not possible due to the high modal density that aircraft fuselage structures exhibit in this frequency range. Classical correlation criteria like the Modal Assurance Criterion require mode shapes and can therefore not be applied. Other correlation criteria using frequency response data, such as the Frequency Domain Assurance Criterion, are highly sensitive to even small structural modifications and fail to indicated the correlation between test and analysis data in the mid-frequency range. Nevertheless, validated numerical models for the mid- to high-frequency ranges are a prerequisite for acoustic comfort predictions of aircraft cabin. This paper presents a new method for the correlation of response data from test and analysis in the mid-frequency range to support model validation in the mid-frequency range and to enable the usage of finite element models in this frequency range. The method is validated on a stiffened cylindrical shell structure, which represents a scale-model of an aircraft fuselage. The correlation criterion presented here is inspired by Statistical Energy Analysis and is based on kinetic energies integrated over frequency bands and spatially integrated over surface areas of the structure. The objective is to indicate frequency bands where the finite element model needs to be adjusted to better match with experimental observations and to locate the areas where these adjustments should be applied.

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

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    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.

  15. Inexpensive automatic ranging for digital voltmeters and frequency counters

    Science.gov (United States)

    Roller, R. F.

    1970-01-01

    Seven integrated circuits incorporated at very low cost into frequency counters and digital voltmeters performing a voltage-to-frequency conversion permit automatic range changing. Extra decades are switched into and out of the counting chain as a function of the counter during the previous counting period.

  16. Chaotic Colpitts Oscillator for the Ultrahigh Frequency Range

    DEFF Research Database (Denmark)

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

    2006-01-01

    . Simulations indicate that chaotic oscillations observed experimentally at higher frequencies, e.g., at about 1000MHz are caused by parasites, like wiring inductances, loss resistance appearing due to skin effect, and collector-emitter capacitance of the transistor. Reliable and reproducible chaos can......PSpice simulation and experimental results demonstrating chaotic performance of the Colpitts oscillator in the ultrahigh frequency (300–1000 MHz) range are presented.Various combinations of the resonance tank parameters are considered to achieve a fundamental frequency as high as possible...... be generated at fundamental frequencies up to about 500MHz with the single-stage Colpitts oscillator using the microwave 9 GHz bipolar junction transistors....

  17. An OFDM Carrier Frequency Offset Estimation Scheme with Wide Fractional Offset Estimation Range

    Directory of Open Access Journals (Sweden)

    C. Yu

    2013-04-01

    Full Text Available In this paper, we propose a carrier frequency offset (CFO estimation scheme which is robust to the fractional CFO variation for orthogonal frequency division multiplexing (OFDM systems. The proposed scheme first performs the envelope equalization process to convert the offset estimation problem to a carrier estimation problem, and then, estimates the integer and fractional parts of CFO by using periodogram of the received signal. Especially, in the estimation stage for fraction CFO, the ratio of the square-roots of periodograms is employed enlarging the estimation range of the stage than that of the conventional scheme. Numerical results demonstrate that the proposed scheme has better estimation performance than the conventional scheme for wider fractional CFO range in various channel conditions.

  18. Bearing fault detection in the acoustic emission frequency range

    Science.gov (United States)

    Tavakoli, Massoud S.

    The effectiveness of using bearing fault detection in the acoustic-emission frequency range is demonstrated using a vertical milling machine as the testbed. The experimental testbed is monitored by an accelerometer and an acoustic emission sensor, and the signals are demodulated by rms enveloping and then fast-Fourier-transformed. The analytical computation of the defect characteristic frequency is explained, and the time histories are given of the enveloped signal and its spectrum. The method is shown to be useful for extracting the repetition rate of the repetitive component of the general signal, and the signal generated by the bearing defect is identified in the frequency ranges of mechanical vibration and acoustic emission. The signal in the acoustic-emission frequency range is shown to be helpful for detecting bearing defects because it not affected by repetitive mechanical noise.

  19. Cross-Linguistic Differences in Bilinguals' Fundamental Frequency Ranges

    Science.gov (United States)

    Ordin, Mikhail; Mennen, Ineke

    2017-01-01

    Purpose: We investigated cross-linguistic differences in fundamental frequency range (FFR) in Welsh-English bilingual speech. This is the first study that reports gender-specific behavior in switching FFRs across languages in bilingual speech. Method: FFR was conceptualized as a behavioral pattern using measures of span (range of fundamental…

  20. 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.

  1. 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.

  2. Tunable and Broadband Differential Phase Sections in Terahertz Frequency Range

    Science.gov (United States)

    Kosiak, O. S.; Bezborodov, V. I.; Kuleshov, Ye. M.; Nesterov, P. K.

    2016-12-01

    Purpose: Studying the quasioptical tunable and broadband differential phase section (DPS) consisting of several birefringent elements (BE) on the basis of form birefringence effect. Design/methodology/approach: Using the polarization scattering matrix method, the impact of the mutual rotation axis of anisotropy of several BE by the amount of phase shift and the position of the plane of anisotropy of resulting DPS is considered. Findings: The DPS tunable in a wide range are shown to be possibly implemented in the case of quarter- wave DPS of two, and in the case of half-wave DPS of three, identical non-tunable BE. The analysis has shown to the possibility of creating a broadband quarter-wave and half-wave DPS. Conclusions: Experimental research has confirmed the possibility of constructing a tunable and broadband DPS. On this basis, tunable and broadband polarization converters, rotators of polarization plane, polarization phase shifters and frequency shifters in the terahertz frequency range can be created.

  3. Optical properties of human nails in THz frequency range

    Science.gov (United States)

    Guseva, Victoria A.; Gusev, Sviatoslav I.; Demchenko, Petr S.; Sedykh, Egor A.; Khodzitsky, Mikhail K.

    2017-03-01

    This work is devoted to investigation of optical properties (dispersion of refractive index, permittivity and absorption coefficient) of human nails in THz frequency range. These data were obtained by THz time-domain spectroscopy (TDS) technique in transmission mode. These results may be used to develop non-invasive technique of human pathologies control using nail as reference sample in reflection mode of THz TDS.

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

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    Yoshiaki Kono

    Full Text Available 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.

  5. 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

  6. A wide-frequency-range air-jet shaker

    Science.gov (United States)

    Herr, Robert W

    1957-01-01

    This paper presents a description of a simple air-jet shaker. Its force can be calibrated statically and appears to be constant with frequency. It is relatively easy to use, and it has essentially massless characteristics. This shaker is applied to define the unstable branch of a frequency-response curve obtained for a nonlinear spring with a single degree of freedom.

  7. 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.

  8. Range-based covariance estimation using high-frequency data: The realized co-range

    NARCIS (Netherlands)

    K. Bannouh (Karim); D.J.C. van Dijk (Dick); M.P.E. Martens (Martin)

    2008-01-01

    textabstractWe introduce the realized co-range, utilizing intraday high-low price ranges to estimate asset return covariances. Using simulations we find that for plausible levels of bid-ask bounce and infrequent and non-synchronous trading the realized co-range improves upon the realized covariance,

  9. 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 (

  10. Context in a wider context

    Directory of Open Access Journals (Sweden)

    John Traxler

    2011-07-01

    Full Text Available This paper attempts to review and reconsider the role of context in mobile learning and starts by outlining definitions of context-aware mobile learning as the technologies have become more mature, more robust and more widely available and as the notion of context has become progressively richer. The future role of context-aware mobile learning is considered within the context of the future of mobile learning as it moves from the challenges and opportunities of pedagogy and technology to the challenges and opportunities of policy, scale, sustainability, equity and engagement with augmented reality, «blended learning», «learner devices», «user-generated contexts» and the «internet of things». This is essentially a perspective on mobile learning, and other forms of technology-enhanced learning (TEL, where educators and their institutions set the agenda and manage change. There are, however, other perspectives on context. The increasing availability and use of smart-phones and other personal mobile devices with similar powerful functionality means that the experience of context for many people, in the form of personalized or location-based services, is an increasingly social and informal experience, rather than a specialist or educational experience. This is part of the transformative impact of mobility and connectedness on our societies brought about by these universal, ubiquitous and pervasive technologies. This paper contributes a revised understanding of context in the wider context (sic of the transformations taking place in our societies. These are subtle but pervasive transformations of jobs, work and the economy, of our sense of time, space and place, of knowing and learning, and of community and identity. This leads to a radical reconsideration of context as the notions of ‹self› and ‹other› are transformed.

  11. Effect of skin dielectric properties on the read range of epidermal ultra-high frequency radio-frequency identification tags.

    Science.gov (United States)

    Oyeka, Dumtoochukwu O; Batchelor, John C; Ziai, Ali Mohamad

    2017-04-01

    This Letter presents an investigation of the effect of human tissue conductivity and permittivity on the performance of epidermal transfer tattoo ultra-high frequency radio-frequency identification (RFID) tags. The measurements were carried out on 20 individuals and the variations in the measured dielectric properties correlate well with variations in the measured tag read range on the individuals and to a lesser extent with their body mass index values. Simulation results also showed the effects of permittivity and conductivity on the designed resonance frequency of the RFID tag.

  12. Effect of skin dielectric properties on the read range of epidermal ultra-high frequency radio-frequency identification tags

    Science.gov (United States)

    Batchelor, John C.; Ziai, Ali Mohamad

    2017-01-01

    This Letter presents an investigation of the effect of human tissue conductivity and permittivity on the performance of epidermal transfer tattoo ultra-high frequency radio-frequency identification (RFID) tags. The measurements were carried out on 20 individuals and the variations in the measured dielectric properties correlate well with variations in the measured tag read range on the individuals and to a lesser extent with their body mass index values. Simulation results also showed the effects of permittivity and conductivity on the designed resonance frequency of the RFID tag. PMID:28461902

  13. 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.

  14. Optical conductivity of warm dense matter in wide frequency range within quantum statistical and kinetic approach

    CERN Document Server

    Veysman, M; Winkel, M; Reinholz, H

    2016-01-01

    Fundamental properties of warm dense matter are described by the dielectric function, which gives access to the frequency-dependent electrical conductivity, absorption, emission and scattering of radiation, charged particles stopping and further macroscopic properties. Different approaches to the dielectric function and the related dynamical collision frequency are compared in a wide frequency range. The high-frequency limit describing inverse bremsstrahlung and the low-frequency limit of the dc conductivity are considered. Sum rules and Kramers-Kronig relation are checked for the generalized linear response theory and the standard approach following kinetic theory. The results are discussed in application to aluminum, xenon and argon plasmas.

  15. 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.

  16. Optimal frequency range for medical radar measurements of human heartbeats using body-contact radar.

    Science.gov (United States)

    Brovoll, Sverre; Aardal, Øyvind; Paichard, Yoann; Berger, Tor; Lande, Tor Sverre; Hamran, Svein-Erik

    2013-01-01

    In this paper the optimal frequency range for heartbeat measurements using body-contact radar is experimentally evaluated. A Body-contact radar senses electromagnetic waves that have penetrated the human body, but the range of frequencies that can be used are limited by the electric properties of the human tissue. The optimal frequency range is an important property needed for the design of body-contact radar systems for heartbeat measurements. In this study heartbeats are measured using three different antennas at discrete frequencies from 0.1 - 10 GHz, and the strength of the received heartbeat signal is calculated. To characterize the antennas, when in contact with the body, two port S-parameters(†) are measured for the antennas using a pork rib as a phantom for the human body. The results shows that frequencies up to 2.5 GHz can be used for heartbeat measurements with body-contact radar.

  17. 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.

  18. Motion Compensation of Moving Targets for High Range Resolution Stepped-Frequency Radar

    Directory of Open Access Journals (Sweden)

    Xiqin Wang

    2008-05-01

    Full Text Available High range resolution (HRR profiling using stepped-frequency pulse trains suffers from range shift and the attenuation/dispersion of range profiles while the target of interest is moving. To overcome these two drawbacks, a new algorithm based on the maximum likelihood (ML estimation is proposed in this paper. Without altering the conventional stepped-frequency waveform, this algorithm can estimate the target velocity and thereby compensate the phase errors caused by the target’s motion. It is shown that the velocity can be accurately estimated and the range profile can be correctly reconstructed.

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

    Science.gov (United States)

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

    2015-09-21

    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.

  20. 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 (Paccessed the range 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.

  1. Ultrafast acoustics in the middle UV range: coherent phonons at higher frequencies and in smaller objects.

    Science.gov (United States)

    Ayrinhac, S; Devos, A; Le Louarn, A; Mante, P-A; Emery, P

    2010-10-15

    We show that the propagation of coherent acoustic phonons generated by femtosecond optical excitation can be clearly resolved using a probe laser in the middle UV (MUV) range. The MUV probe is easily produced from a high-repetition-rate femtosecond laser and a homemade frequency tripler. We present various experimental results that demonstrate efficient and high frequency detection of acoustic phonons. Thus, we show that the MUV range offers a unique way to reach higher frequencies and probe smaller objects in ultrafast acoustics.

  2. 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...

  3. 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

  4. Frequency-swept Light Sources for Optical Coherence Tomography in the 1060nm range

    DEFF Research Database (Denmark)

    Marschall, Sebastian

    instrument in the biomedical eld, especially in ophthalmology, where it is used for diagnosing retinal diseases. Using light at 1060nm permits deep penetration into the retina and into the layers beneath, the choroid and the sclera. This wavelength range is also benecial for imaging in eyes affected...... by cataract. For the 1060nm band, rapidly tunable lasers|so-called swept sources|are available which enable ultra-high speed acquisition of large three-dimensional datasets. However, these light sources require further improvements: higher output power for sufficient signal quality and wider tuning bandwidth...... for better depth resolution in combination with high tuning speed. We investigate the performance of novel semiconductor laser gain media in fiber-based high-speed swept source prototypes. We demonstrate high output power using a tapered amplifier, and we achieve improved depth resolution with a broadband...

  5. The BDS Triple Frequency Pseudo-range Correlated Stochastic Model of Single Station Modeling Method

    Directory of Open Access Journals (Sweden)

    HUANG Lingyong

    2017-05-01

    Full Text Available In order to provide a reliable pseudo-range stochastic model, a method is studied to estimate the BDS triple-frequency pseudo-range related stochastic model based on three BDS triple-frequency pseudo-range minus carrier (GIF combinations using the data of a single station. In this algorithm, the low order polynomial fitting method is used to fit the GIF combination in order to eliminate the error and other constants except non pseudo noise at first. And then, multiple linear regression analysis method is used to model the stochastic function of three linearly independent GIF combinations. Finally the related stochastic model of the original BDS triple-frequency pseudo-range observations is obtained by linear transformation. The BDS triple-frequency data verification results show that this algorithm can get a single station related stochastic model of BDS triple-frequency pseudo-range observation, and it is advantageous to provide accurate stochastic model for navigation and positioning and integrity monitoring.

  6. Floquet engineering of long-range p -wave superconductivity: Beyond the high-frequency limit

    Science.gov (United States)

    Li, Zeng-Zhao; Lam, Chi-Hang; You, J. Q.

    2017-10-01

    It has been shown that long-range p -wave superconductivity in a Kitaev chain can be engineered via an ac field with a high frequency [M. Benito et al., Phys. Rev. B 90, 205127 (2014), 10.1103/PhysRevB.90.205127]. For its experimental realization, however, theoretical understanding of Floquet engineering with a broader range of driving frequencies becomes important. In this paper, focusing on the ac-driven tunneling interactions of a Kitaev chain, we investigate effects from the leading correction to the high-frequency limit on the emergent p -wave superconductivity. Importantly, we find new engineered long-range p -wave pairing interactions that can significantly alter the ones in the high-frequency limit at long interaction ranges. We also find that the leading correction additionally generates nearest-neighbor p -wave pairing interactions with a renormalized pairing energy, long-range tunneling interactions, and, in particular, multiple pairs of Floquet Majorana edge states that are destroyed in the high-frequency limit.

  7. 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.

  8. An atomic magnetometer with autonomous frequency stabilization and large dynamic range

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, S., E-mail: spradhan@barc.gov.in, E-mail: pradhans75@gmail.com; Poornima,; Dasgupta, K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 85 (India); Homi Bhabha National Institute, Department of Atomic Energy, Mumbai 85 (India); Mishra, S.; Behera, R. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 85 (India)

    2015-06-15

    The operation of a highly sensitive atomic magnetometer using elliptically polarized resonant light is demonstrated. It is based on measurement of zero magnetic field resonance in degenerate two level systems using polarimetric detection. The transmitted light through the polarimeter is used for laser frequency stabilization, whereas reflected light is used for magnetic field measurement. Thus, the experimental geometry allows autonomous frequency stabilization of the laser frequency leading to compact operation of the overall device and has a preliminary sensitivity of <10 pT/Hz{sup 1/2} @ 1 Hz. Additionally, the dynamic range of the device is improved by feedback controlling the bias magnetic field without compromising on its sensitivity.

  9. Evaluation of the spectral fit algorithm as functions of frequency range and deltakaeff.

    Science.gov (United States)

    Bigelow, Timothy A; O'Brien, William D

    2005-11-01

    Considerable effort has been directed at quantifying the properties of the tissue microstructure (i.e., scatterer correlation length) to diagnose disease and monitor treatment. In vivo assessments have had limited success due to frequency-dependent attenuation along the propagation path (i.e., total attenuation) masking the frequency dependence of the scattering from the tissue microstructure. Previously, both total attenuation and scatterer correlation length, given by the effective radius, were solved simultaneously by a two-parameter minimization of the mean squared error between a reference spectrum, modified by the attenuation and scatterer effective radius, and the backscattered waveforms using an algorithm termed the spectral fit algorithm. Herein, the impact of frequency range (largest frequency minus smallest frequency) and deltakaeff (largest kaeff value minus smallest kaeff value; k is wave number and aeff is scatterer effective radius) used by the spectral fit algorithm on estimating the scatterer effective radius, and total attenuation was assessed by computer simulations while excluding frequencies of the backscattered power spectrum dominated by electronic noise. The simulations varied the effective radius of the scatterers (5 microm to 150 microm), the attenuation of the region (0 to 1 dB/cm-MHz), the bandwidth of the source, and the amount of electronic noise added to the radio frequency (rf) waveforms. The center frequency of the source was maintained at 8 MHz. Comparable accuracy and precision of the scatterer effective radius were obtained for all the simulations whenever the same deltakaeff was used to obtain the estimates. A deltakaeff of 1 gave an accuracy and precision of approximately 15% +/- 35%, and a width of 1.5 gave an accuracy and precision of approximately 5% +/- 15% consistently for all of the simulations. Similarly, the accuracy and precision of the total attenuation estimate were improved by increasing the frequency range used by

  10. The effects of tones on speaking frequency and intensity ranges in Mandarin and Min dialects

    Science.gov (United States)

    Chen, Sheng H.

    2005-05-01

    The differences of speaking frequency and intensity in different tonal dialects has not been widely investigated. The purposes of this study were (1) to compare the speaking frequency and speaking intensity ranges of Mandarin and Min and (2) to compare the speaking frequency and intensity ranges of Mandarin and Min to those of American English. The subjects were 80 normal Taiwanese adults divided into two dialect groups, Mandarin and Min. The speaking F0, the highest speaking F0, the lowest speaking F0, the maximum range of speaking F0, and the intensity counterpart were obtained from reading in their native dialects. Statistical analysis revealed that Min speakers had a significantly greater maximum range of speaking intensity and a smaller lowest speaking intensity than Mandarin speakers, which indicated tonal effects by speakers of the Min dialect. Moreover, Mandarin and Min speakers had a greater maximum range of speaking F0 and maximum range of speaking intensity than American English speakers. The data may provide an assessment tool for Mandarin speakers and Min speakers. .

  11. Long-range vibration sensor based on correlation analysis of optical frequency-domain reflectometry signals.

    Science.gov (United States)

    Ding, Zhenyang; Yao, X Steve; Liu, Tiegen; Du, Yang; Liu, Kun; Han, Qun; Meng, Zhuo; Chen, Hongxin

    2012-12-17

    We present a novel method to achieve a space-resolved long- range vibration detection system based on the correlation analysis of the optical frequency-domain reflectometry (OFDR) signals. By performing two separate measurements of the vibrated and non-vibrated states on a test fiber, the vibration frequency and position of a vibration event can be obtained by analyzing the cross-correlation between beat signals of the vibrated and non-vibrated states in a spatial domain, where the beat signals are generated from interferences between local Rayleigh backscattering signals of the test fiber and local light oscillator. Using the proposed technique, we constructed a standard single-mode fiber based vibration sensor that can have a dynamic range of 12 km and a measurable vibration frequency up to 2 kHz with a spatial resolution of 5 m. Moreover, preliminarily investigation results of two vibration events located at different positions along the test fiber are also reported.

  12. 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

    to picoseconds in the previous experiments. For the broad spectrum, the additional effect of group delay dispersion (GDD) has to be taken into account, since the Raman process relies on the coherent interaction of all frequency components of the spectrum, with GDD influencing the relative phase which leads......This thesis presents for the first time the experimental implementation of coherent Raman oscillations with a femtosecond frequency comb for transition frequencies in the THz range. The technique has been successfully demonstrated before to drive Raman transitions between hyperfine structure states...... to destructive interference. Therefore, GDD is compensated using a prism compressor and it is shown quantitatively that the measured GDD matches the theoretically predicted effect on the total Raman Rabi frequency. For the measurements and compensation of GDD, the techniques of interferometric autocorrelation...

  13. 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. Simulations...

  14. Semiannual Status Report. [excitation of electromagnetic waves in the whistler frequency range

    Science.gov (United States)

    1994-01-01

    During the last six months, we have continued our study of the excitation of electromagnetic waves in the whistler frequency range and the role that these waves will play in the acceleration of electrons and ions in the auroral region. A paper entitled 'Electron Beam Excitation of Upstream Waves in the Whistler Mode Frequency Range' was listed in the Journal of Geophysical Research. In this paper, we have shown that an anisotropic electron beam (or gyrating electron beam) is capable of generating both left-hand and right-hand polarized electromagnetic waves in the whistler frequency range. Since right-hand polarized electromagnetic waves can interact with background electrons and left-hand polarized waves can interact with background ions through cyclotron resonance, it is possible that these beam generated left-hand and right-hand polarized electromagnetic waves can accelerate either ions or electrons (or both), depending on the physical parameters under consideration. We are currently carrying out a comprehensive study of the electromagnetic whistler and lower hybrid like waves observed in the auroral zone using both wave and particle data. Our first task is to identify these wave modes and compare it with particle observations. Using both the DE-1 particle and wave measurements, we can positively identify those electromagnetics lower hybrid like waves as fast magnetosonic waves and the upper cutoff of these waves is the local lower hybrid frequency. From the upper cutoff of the frequency spectrum, one can infer the particle density and the result is in very good agreement with the particle data. Since these electromagnetic lower hybrid like waves can have frequencies extended down to the local ion cyclotron frequency, it practically confirms that they are not whistler waves.

  15. Excitation of Lamb waves over a large frequency-thickness product range for corrosion detection

    Science.gov (United States)

    Zeng, Liang; Luo, Zhi; Lin, Jing; Hua, Jiadong

    2017-09-01

    For corrosion detection, it is often desirable that a Lamb wave mode is highly sensitive to surface thinning and enjoys some degree of mode purity at a particular frequency. In view of this, this paper aims to generate a variety of Lamb wave modes over broad frequency bands to ensure an abundant supply of candidates for corrosion detection, and further, establish a strategy to find appropriate operation points efficiently and effectively. Firstly, a short-duration laser pulse is applied to generate Lamb waves over a large frequency-thickness product range. The selection of symmetric modes or anti-symmetric modes is obtained by addition or subtraction of signals captured by two identical transducers which are symmetrically coupled on both sides of the plate. Subsequently, the S0 mode at a non-dispersive frequency bandwidth is employed to improve the accuracy of the transmitter-receiver distance. Based on those, three selection criteria including mode separability, amplitude ratio and corrosion sensitivity, are presented to efficiently determine the suitable operation points (i.e., mode types and frequencies). The experimental results show that the simulated corrosion could be correctly detected and accurately localized at the chosen modes and frequencies.

  16. Wide-range dynamic strain measurements based on K-BOTDA and frequency-agile technique

    Science.gov (United States)

    Zhou, Dengwang; Dong, Yongkang; Wang, Benzhang; Zhang, Hongying; Lu, Zhiwei

    2017-04-01

    We propose and demonstrate a novel fast Brillouin optical time-domain analysis system using the coefficient K spectrum which is defined as the ratio of phase-shift and gain of Brillouin amplification, where K features linear response, immune to the variation of pump power and a wide measure range. For a 30ns-square pump pulse, the frequency span of K spectrum can reach up to 200MHz. In dynamic strain experiment, a multi-slope assisted K-BOTDA with the measured strain of 5358.3μɛ and the vibration frequency of 6.01Hz and 12.05Hz are demonstrated.

  17. Voice training and changing weight--are they reflected in speaking fundamental frequency, voice range, and pitch breaks of 13-year-old girls? A longitudinal study.

    Science.gov (United States)

    Willis, Elizabeth C; Kenny, Dianna T

    2011-09-01

    Assessment of the voice-change progress of 20 girls (12-13 years) over 1 year by observing changes in speaking fundamental frequency (SFo), voice range, and register pitch breaks in the context of weight, height, voice training, and self-perception. One-year longitudinal collective case study. Twenty girls were recorded at the beginning and end of a year; nine girls were recorded another three times. SFo, vocal range, and characteristics were analyzed and interactions between these data assessed against weight and height to indicate pubertal development, and to test the hypothesis that changes in weight, height, SFo, and pitch breaks were related. Effects of training and the girls' self-perception of their voice use were also assessed. Vocal characteristics changed as the girls passed through different weight ranges. During 47.5-52.4 kg (called band 2) and 52.4-57.5 kg (band 3), there was progressive contraction of vocal range and in some girls a slight rise in SFo between recording times 1 and 5. Both high- and low-pitch breaks were present in 45% of girls' voices. Girls in band 4 (pitch breaks in vocal-range areas that indicated the development of adult vocal registers. In this study, voice-trained girls were heavier, had higher SFo, used wider speech-range inflection, had a higher vocal range, and greater voice-use confidence; all girls lost confidence in their voice use over the year. In this longitudinal study of twenty 13-year-old girls, voice changes in SFo, vocal range, and pitch-break frequency were synchronous with certain weight ranges. Girls with training registered higher maximum phonational frequency and were more confident in their voice use than girls without training. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

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

    Science.gov (United States)

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

    2017-02-01

    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.

  19. Impact of energetic particle orbits on long range frequency chirping of BGK modes

    Science.gov (United States)

    Hezaveh, H.; Qu, Z. S.; Layden, B.; Hole, M. J.

    2017-12-01

    Long range frequency chirping of Bernstein-Greene-Kruskal modes, whose existence is determined by the fast particles, is investigated in cases where these particles do not move freely and their motion is bounded to restricted orbits. A nonuniform equilibrium magnetic field is included into the bump-on-tail instability problem of a plasma wave. The parallel field gradients account for the existence of different orbit topologies of energetic particles. With respect to fast particles dynamics, the extended model captures the range of particles motion (trapped/passing) with energy and thus represents a more realistic 1D picture of the long range sweeping events observed for weakly damped modes, e.g. global Alfven eigenmodes, in tokamaks. The Poisson equation is solved numerically along with bounce averaging the Vlasov equation in the adiabatic regime. We demonstrate that the shape and the saturation amplitude of the nonlinear mode structure depends not only on the amount of deviation from the initial eigenfrequency but also on the initial energy of the resonant electrons in the equilibrium magnetic field. Similarly, the results reveal that the resonant electrons following different equilibrium orbits in the nonuniform field lead to different rates of frequency evolution. As compared to the previous model (Breizman 2010 Nucl. Fusion 50 084014), it is shown that the frequency sweeps with lower rates. The additional physics included in the model enables a more complete 1D description of the range of phenomena observed in experiments.

  20. Waveguiding Effect in the Gigahertz Frequency Range in Pillar-based Phononic-Crystal Slabs

    Science.gov (United States)

    Pourabolghasem, Reza; Dehghannasiri, Razi; Eftekhar, Ali Asghar; Adibi, Ali

    2018-01-01

    The waveguiding effect for a phononic-crystal (PnC)-based device operating in the gigahertz (GHz) frequency regime is experimentally demonstrated. To that end, a metallic pillar-based PnC membrane with a PnC band gap in the GHz frequency range is designed, and, based on that, an acoustic waveguide operating in the GHz regime is designed and fabricated. To characterize the fabricated PnC waveguide, a set of focusing interdigital transducers is designed and fabricated, enabling efficient excitation and detection of acoustic signals inside the PnC waveguide. The finite-element method is used to study the acoustic properties of the proposed structures and optimize their design. Experimental evidence supporting the existence of the waveguiding effect in the proposed structure in the GHz frequency regime is provided, showing reasonable agreement with the numerical calculations.

  1. 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)

  2. Propagation in a shearing plasma. II - Turbulence and the frequency range of pulsar microstructure

    Science.gov (United States)

    Harding, A. K.; Tademaru, E.

    1980-01-01

    Numerical calculations are presented which explore the propagation of radio waves and pulses through a turbulent shearing plasma. A stochastic model is used to describe the turbulent velocity field, in which random fluctuations are superposed on a mean profile. Both Gaussian wave packets and shot-noise pulses polarized in the plane of shearing acquire quasi-periodic intensity modulations above the rest-frame plasma frequency. The frequency range over which these modulations appear is shown to depend on the spatial correlation length of the turbulent fluctuations and on their standard deviation from the mean velocity. The period of the modulations is variable from one realization of the random process to the next, and the average period is frequency dependent. The results of these calculations lend further support to a model for pulsar microstructure in which periodic micropulses are pure temporal modulations of the emitted radiation due to propagation effects in magnetospheric shearing regions. It is shown that turbulence on a scale of approximately 10 cm can produce these quasi-periodic modulations over a frequency range comparable to that of observed microstructure.

  3. 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.

  4. Artificial Temperature Anisotropy of Crystals in X-Ray Frequency Range

    Science.gov (United States)

    Mkrtchyan, Vahram P.; Gasparyan, Laura G.; Balyan, Minas K.

    2010-04-01

    The effect of artificial temperature anisotropy of crystals in X-ray frequency range was observed for the first time and an effort to theoretically interpret this effect in Bragg-Laue diffraction case was made. It was established that an isotropic crystal optically turns into an artificially anisotropic one with optical axis along the direction of applied external influence as a symmetry axis, giving rise to the double refraction.

  5. Polarization-Entangled Photon Pairs From Periodically-Poled Crystalline Waveguides Over a Range of Frequencies.

    Science.gov (United States)

    Heberle, Dylan A; Levine, Zachary H

    2013-01-01

    We propose a method to extend the frequency range of polarization entanglement in periodically poled rubidium-doped potassium titanyl phosphate (Rb:KTP) waveguides. Our calculations predict that output wavelengths from 1130 nm to 1257 nm may be achieved using Rb:KTP by the appropriate selection of a direction of propagation for the waveguide. The fidelity using a poling period of 1 mm is approximately 0.98.

  6. 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.

  7. 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

  8. An Ultrasonic Multiple-Access Ranging Core Based on Frequency Shift Keying Towards Indoor Localization

    Directory of Open Access Journals (Sweden)

    Laurent Segers

    2015-07-01

    Full Text Available This paper describes a new approach and implementation methodology for indoor ranging based on the time difference of arrival using code division multiple access with ultrasound signals. A novel implementation based on a field programmable gate array using finite impulse response filters and an optimized correlation demodulator implementation for ultrasound orthogonal signals is developed. Orthogonal codes are modulated onto ultrasound signals using frequency shift keying with carrier frequencies of 24.5 kHz and 26 kHz. This implementation enhances the possibilities for real-time, embedded and low-power tracking of several simultaneous transmitters. Due to the high degree of parallelism offered by field programmable gate arrays, up to four transmitters can be tracked simultaneously. The implementation requires at most 30% of the available logic gates of a Spartan-6 XC6SLX45 device and is evaluated on accuracy and precision through several ranging topologies. In the first topology, the distance between one transmitter and one receiver is evaluated. Afterwards, ranging analyses are applied between two simultaneous transmitters and one receiver. Ultimately, the position of the receiver against four transmitters using trilateration is also demonstrated. Results show enhanced distance measurements with distances ranging from a few centimeters up to 17 m, while keeping a centimeter-level accuracy.

  9. An Ultrasonic Multiple-Access Ranging Core Based on Frequency Shift Keying Towards Indoor Localization.

    Science.gov (United States)

    Segers, Laurent; Van Bavegem, David; De Winne, Sam; Braeken, An; Touhafi, Abdellah; Steenhaut, Kris

    2015-07-30

    This paper describes a new approach and implementation methodology for indoor ranging based on the time difference of arrival using code division multiple access with ultrasound signals. A novel implementation based on a field programmable gate array using finite impulse response filters and an optimized correlation demodulator implementation for ultrasound orthogonal signals is developed. Orthogonal codes are modulated onto ultrasound signals using frequency shift keying with carrier frequencies of 24.5 kHz and 26 kHz. This implementation enhances the possibilities for real-time, embedded and low-power tracking of several simultaneous transmitters. Due to the high degree of parallelism offered by field programmable gate arrays, up to four transmitters can be tracked simultaneously. The implementation requires at most 30% of the available logic gates of a Spartan-6 XC6SLX45 device and is evaluated on accuracy and precision through several ranging topologies. In the first topology, the distance between one transmitter and one receiver is evaluated. Afterwards, ranging analyses are applied between two simultaneous transmitters and one receiver. Ultimately, the position of the receiver against four transmitters using trilateration is also demonstrated. Results show enhanced distance measurements with distances ranging from a few centimeters up to 17 m, while keeping a centimeter-level accuracy.

  10. Supplementary Golay pair for range side lobe suppression in dual-frequency tissue harmonic imaging.

    Science.gov (United States)

    Shen, Che-Chou; Wu, Chi; Peng, Jun-Kai

    2015-02-01

    In dual-frequency (DF) harmonic imaging, the second harmonic signal at second harmonic (2f0) frequency and the inter-modulation harmonic signal at fundamental (f0) frequency are simultaneously imaged for spectral compounding. When the phase-encoded Golay pair is utilized to improve the harmonic signal-to-noise ratio (SNR), however, the DF imaging suffers from range side lobe artifacts due to spectral cross-talk with other harmonic components at DC and third harmonic (3f0) frequency. In this study, a supplementary Golay pair is developed to suppress the range side lobes in combination with the original Golay pair. Since the phase code of the DC interference cannot be manipulated, the supplementary Golay is designed to reverse the polarity of the 3f0 interference and the f0 signal while keeping the 2f0 signal unchanged. For 2f0 imaging, the echo summation of the supplementary and the original Golay can cancel the 3f0 interference. On the contrary, the echo difference between the two Golay pairs can eliminate the DC interference for f0 imaging. Hydrophone measurements indicate that the range side lobe level (RSLL) increases with the signal bandwidth of DF harmonic imaging. By using the combination of the two Golay pairs, the achievable suppression of RSLL can be 3 and 14 dB, respectively for the f0 and 2f0 harmonic signal. B-mode phantom imaging also verifies the presence of range side lobe artifacts when only the original Golay pair is utilized. In combination with the supplementary Golay pair, the artifacts are effectively suppressed. The corresponding range side lobe magnitude reduces by about 8 dB in 2f0 imaging but remains unchanged in f0 imaging. Meanwhile, the harmonic SNR improves by 8-10 dB and the contrast-to-noise ratio of harmonic image increases from about 1 to 1.2 by spectral compounding. For DF tissue harmonic imaging, the spectral cross-talk in Golay excitation results in severe range side lobe artifacts. To restore the image quality, two particular

  11. A nonlinear model of magnetorheological elastomer with wide amplitude range and variable frequencies

    Science.gov (United States)

    Wang, Qi; Dong, Xufeng; Li, Luyu; Ou, Jinping

    2017-06-01

    To develop control algorithms that taking maximum advantage of rapidly varying rheological properties of MR elastomer devices, models must be developed that can adequately characterize the smart material’s intrinsic nonlinearity. However, most existing MRE models are only effective within a narrow strain amplitude range and under certain loading frequencies. To derive a MRE model with better applicability, MR elastomer samples were fabricated and their steady-state response under harmonic loading with different strain amplitudes, frequencies and magnetic fields were tested. Following a review of several existing models of MR elastomer, a new revised Bouc-Wen model is proposed that can effectively portray the behavior of the material. Comparison with experimental results indicates that the model is accurate over a wide range of frequencies, strain amplitudes and magnetic flux densities. A simplified model was then proposed after parametric study. As the magnetic field is the only determinant of the parameters, the simplified model is adequate for base isolation devices design and simulation.

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

    Science.gov (United States)

    Kuipers, B W M; Bakelaar, I A; Klokkenburg, M; Erné, 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 frequencies make it possible to study the rotational dynamics of large magnetic colloidal particles or aggregates dispersed in a liquid. The distinguishing features of the setup are the novel multilayered cylindrical coils with a large sample volume and a large number of secondary turns (55 000) to measure induced voltages with a good signal-to-noise ratio, the use of a dual channel function generator to provide an ac current to the primary coils and an amplitude- and phase-adjusted compensation voltage to the dual phase differential lock-in amplifier, and the measurement of several vector quantities at each frequency. We present the electrical impedance characteristics of the coils, and we demonstrate the performance of the setup by measurement on magnetic colloidal dispersions covering a wide range of characteristic relaxation frequencies and magnetic susceptibilities, from chi approximately -10(-5) for pure water to chi>1 for concentrated ferrofluids.

  13. Performance Analysis of Frequency Shift Keyed Signals in a Sonar Ranging System

    Science.gov (United States)

    Kodama, Tetsuji; Nakahira, Kenji; Koyama, Yuu; Murakami, Junichi

    Pulsed ultrasonic distance measurement systems are frequently used in robotics applications, thanks to their low cost and small size. The pulse compression techniques, originally developed by radar engineers, were adopted to eliminate frequent misreadings caused by crosstalk or external ultrasound sources. High-performance computing systems for the implementation of pulse compression techniques enable reliable and accurate distance measurement. In most cases however, they significantly increase the complexity of the total system, cutting down one of the advantages of ultrasonic systems. The ultrasonic ranging using a digital polarity correlator can overcome this drawback, because the cost of realizing delay and multiplication for each point on the polarity correlation function as a parallel operation is very low. This paper presents an analysis of the binary coded frequency shift keyed signals for the ultrasonic ranging using a digital polarity correlator. The spectra of the frequency shift keyed signals have been observed to be narrow compared with the spectra of the corresponding phase shift keyed signals. This suggests the possibility of a more reliable and accurate distance measurement with the frequency shift keyed signals in terms of occupied bandwidth.

  14. Hematite from Natural Iron Stones as Microwave Absorbing Material on X-Band Frequency Ranges

    Science.gov (United States)

    Zainuri, Mochamad

    2017-05-01

    This study has been investigated the effect of hematite as microwave absorbing materials (RAM) on X-Band frequency ranges. Hematite was succesfully processed by coprecipitation method and calcined at 500 °C for 5 hour. It was synthesized from natural iron stones from Tanah Laut, South Kalimantan, Indonesia. The products were characterized by X-ray diffraxtion (XRD), conductivity measurement, Vibrating Sample Magnetometer (VSM), and Vector Network Analyzer (VNA). The result was shown that hematite has conductivity value on (2.5-3).10-7 S/cm and be included as dielectric materials. The hysterisis curve was shown that hematite was a super paramagnetic materials. The product was mixed on paint with procentage 10% of total weight and coated on steel grade AH36 with spray methods. Then, the maximum of reflection loss on x - band’s frequency range (8,2-12,4) GHz was -7 dB on frequency of 10.5 GHz. It mean that almost 50% electromagnetic energy was absorbed by hematite.

  15. Estimation of the RF Characteristics of Absorbing Materials in Broad RF Frequency Ranges

    CERN Document Server

    Fandos, R

    2008-01-01

    Absorbing materials are very often used in RF applications. Their electromagnetic characteristics (relative permittivity εr, loss tangent tan δ and conductivity σ) are needed in order to obtain a high-quality design of the absorbing pieces in the frequency range of interest. Unfortunately, suppliers often do not provide these quantities. A simple technique to determine them, based on the RF measurement of the disturbance created by the insertion of a piece of absorber in a waveguide, is presented in this note. Results for samples of two different materials, silicon carbide and aluminum nitride are presented. While the former has a negligible conductivity at the working frequencies, the conductivity of the latter has to be taken into account in order to obtain a meaningful estimation of εr and tan δ. The equations of Kramers & Kronig have been applied to the data as a cross check, confirming the results.

  16. Active stabilization of error field penetration via control field and bifurcation of its stable frequency range

    Science.gov (United States)

    Inoue, S.; Shiraishi, J.; Takechi, M.; Matsunaga, G.; Isayama, A.; Hayashi, N.; Ide, S.

    2017-11-01

    An active stabilization effect of a rotating control field against an error field penetration is numerically studied. We have developed a resistive magnetohydrodynamic code ‘AEOLUS-IT’, which can simulate plasma responses to rotating/static external magnetic field. Adopting non-uniform flux coordinates system, the AEOLUS-IT simulation can employ high magnetic Reynolds number condition relevant to present tokamaks. By AEOLUS-IT, we successfully clarified the stabilization mechanism of the control field against the error field penetration. Physical processes of a plasma rotation drive via the control field are demonstrated by the nonlinear simulation, which reveals that the rotation amplitude at a resonant surface is not a monotonic function of the control field frequency, but has an extremum. Consequently, two ‘bifurcated’ frequency ranges of the control field are found for the stabilization of the error field penetration.

  17. 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.

  18. 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.

  19. Wideband Monopole Fractal Heptagonal Antenna Implementation in X-Band Frequency Range

    Science.gov (United States)

    Iqbal, Muhammad Naeem; Ur-Rahman, Hamood; Tauqeer, T.; Ramer, Rodica

    2017-10-01

    A wideband heptagonal fractal monopole antenna with coplanar waveguide feed is designed and fabricated in X-band frequency range. Comparison of heptagonal fractal monopole antennas with two different substrates to achieve optimum efficiency for UWB applications is presented. FR4 and RT/Duroid 5880 substrates are used for antenna design and fabrication. Four iterations of base shape are used. Fractal antenna has omni-directional radiation pattern. Simulated and measured results showed that monopole fractal antenna with RT/Duroid 5880 substrate has better performance than fractal antenna with FR4 substrate in terms of bandwidth and return loss. Major application area of proposed antenna is wireless body area networks.

  20. A New Algorithm for Joint Range-DOA-Frequency Estimation of Near-Field Sources

    Directory of Open Access Journals (Sweden)

    Jian-Feng Chen

    2004-03-01

    Full Text Available This paper studies the joint estimation problem of ranges, DOAs, and frequencies of near-field narrowband sources and proposes a new computationally efficient algorithm, which employs a symmetric uniform linear array, uses eigenvalues together with the corresponding eigenvectors of two properly designed matrices to estimate signal parameters, and does not require searching for spectral peak or pairing among parameters. In addition, the proposed algorithm can be applied in arbitrary Gaussian noise environment since it is based on the fourth-order cumulants, which is verified by extensive computer simulations.

  1. Dielectric properties of the lithium-titanium ferrite ceramics in a wide frequency range

    Science.gov (United States)

    Surzhikov, A. P.; Gyngazov, S. A.; Lysenko, E. N.; Frangul'yan, T. S.; Malyshev, A. V.

    2015-06-01

    Electrophysical properties of the Li-Ti ferrite ceramics with the spinel structure (Li0.649Fe1.598Ti0.5Zn0.2Mn0.051O4) are studied in the frequency interval 0.5-2.5 GHz at temperatures ranging from room temperature to 530 K. The thermal emf of the ferrite ceramic samples is studied. It is demonstrated that the sample under study exhibits electron conduction. The calculated results are used to interpret the conduction mechanism using the hopping model.

  2. Mid-frequency sound propagation through internal waves at short range with synoptic oceanographic observations.

    Science.gov (United States)

    Rouseff, Daniel; Tang, Dajun; Williams, Kevin L; Wang, Zhongkang; Moum, James N

    2008-09-01

    Preliminary results are presented from an analysis of mid-frequency acoustic transmission data collected at range 550 m during the Shallow Water 2006 Experiment. The acoustic data were collected on a vertical array immediately before, during, and after the passage of a nonlinear internal wave on 18 August, 2006. Using oceanographic data collected at a nearby location, a plane-wave model for the nonlinear internal wave's position as a function of time is developed. Experimental results show a new acoustic path is generated as the internal wave passes above the acoustic source.

  3. 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

    . It is realized by configuring a full-bridge mode and a half-bridge mode operation during each switching cycle. The fixed-frequency phase-shift control schemes are applied and the normalized voltage gain can be always from 0.5 to 1, regardless of the load. The transformer root-mean-square (RMS) currents in both...... the forward and the reverse modes have a negligible variation with respect to the voltage gain, which is beneficial to low conduction losses throughout a wide voltage range. Moreover, the applied MOSFETs are soft-switched, allowing for minimum switching losses. Both the operation principles...

  4. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

    NARCIS (Netherlands)

    Bongers, W. A.; van Beveren, V.; Thoen, D. J.; Nuij, Pjwm; M.R. de Baar,; Donne, A. J. H.; Westerhof, E.; Goede, A. P. H.; Krijger, B.; van den Berg, M. A.; Kantor, M.; M. F. Graswinckel,; Hennen, B.A.; Schüller, F. C.

    2011-01-01

    An intermediate frequency (IF) band digitizing radiometer system in the 100-200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the

  5. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

    NARCIS (Netherlands)

    Bongers, WA.; Van Beveren, V.; Thoen, D.J.; Nuij, P.J.W.M.; De Baar, M.R.; Donné, A.J.H.; Westerhof, E.; Goede, A.P.H.; Krijger, B.; Van den Berg, M.A.; Kantor, M.; Graswinckel, M.F.; Hennen, B.A.; Schüller, F.C.

    2011-01-01

    An intermediate frequency (IF) band digitizing radiometer system in the 100–200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the

  6. 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.

  7. flatFLIM: enhancing the dynamic range of frequency domain FLIM.

    Science.gov (United States)

    Schuermann, Klaus C; Grecco, Hernán E

    2012-08-27

    Fluorescence Lifetime Imaging Microscopy (FLIM) is a quantitative technique to probe the nanoenvironment of fluorescent molecules. It is the most robust way to quantify Förster Resonance Energy Transfer (FRET) as it allows reliable differentiation between concentration changes and quenching. In this way, molecular interactions can be imaged in single living cells. The most common wide-field implementation is homodyne Frequency Domain (FD) FLIM, which determines the fluorescence lifetime by measuring the phase and modulation changes of the fluorescence in each pixel upon excitation with a light source modulated at a high frequency. The fluorescence lifetimes are derived from a stack of images acquired at different phase shifts between excitation and detection. In this work we describe a simple method to enhance the dynamic range of FD-FLIM based on precompensating the expected fluorescence modulation by varying the laser power through the phase stack. We show theoretically and experimentally that most of the dynamic range of the camera can be recovered to quantify cells with different intensities. This improvement can be added to any FD-FLIM setup with minimal modifications, enhancing the throughput of information content.

  8. Acoustic metamaterial panel for both fluid passage and broadband soundproofing in the audible frequency range

    Science.gov (United States)

    Jung, Jae Woong; Kim, Jae Eun; Lee, Jin Woo

    2018-01-01

    We present the design, including an experimental demonstration, of an acoustic metamaterial panel aimed at reducing incoming broadband noise in the audible frequency range while allowing an incoming fluid to pass through the holes formed in the panel. The noise reduction performance of the proposed acoustic metamaterial panel is attributed to an array of annular cavities enclosing the fluid passage holes. The acoustic behavior of the acoustic metamaterial panel is theoretically analyzed by the transfer matrix method, and an equivalent acoustic impedance of each annular cavity is included with its effective length in the derived transfer matrix. The effective bulk modulus for the acoustic metamaterial panel is then extracted from the transmission and reflection coefficients by using the retrieval method. It is shown that the frequency range of the negative effective bulk modulus coincides with the stop band of the acoustic metamaterial panel. The underlying physical mechanism for the negative effective bulk modulus is attributed to the out-of-phase motion of vibrating particles in adjacent annular cavities. A calculated transmission coefficient curve of the acoustic metamaterial panel is shown to be in good agreement with the measured one. The findings presented in this work should be useful in the design of a holey soundproof panel.

  9. A Novel Unit Cell for Active Switches in the Millimeter-Wave Frequency Range

    Science.gov (United States)

    Müller, Daniel; Scherer, Gunnar; Lewark, Ulrich J.; Massler, Hermann; Wagner, Sandrine; Tessmann, Axel; Leuther, Arnulf; Zwick, Thomas; Kallfass, Ingmar

    2018-02-01

    This paper presents a novel transistor unit cell which is intended to realize compact active switches in the high millimeter-wave frequency range. The unit cell consists of the combination of shunt and common gate transistor within a four-finger transistor cell, achieving gain in the amplifying state as well as good isolation in the isolating state. Gate width-dependent characteristics of the unit cell as well as the design of actual switch implementations are discussed in detail. To verify the concept, two switches, a single pole double throw (SPDT) switch and single pole quadruple throw (SP4T) switch, intended for the WR3 frequency range (220-325 GHz) were manufactured and characterized. The measured gain at 250 GHz is 4.6 and 2.2 dB for the SPDT and SP4T switch, respectively. An isolation of more than 24 dB for the SPDT switch and 12.8 dB for the SP4T switch was achieved.

  10. 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.

  11. Frequency-Range Distribution of Boulders Around Cone Crater: Relevance to Landing Site Hazard Avoidance

    Science.gov (United States)

    Clegg-Watkins, R. N.; Jolliff, B. L.; Lawrence, S. J.

    2016-01-01

    Boulders represent a landing hazard that must be addressed in the planning of future landings on the Moon. A boulder under a landing leg can contribute to deck tilt and boulders can damage spacecraft during landing. Using orbital data to characterize boulder populations at locations where landers have safely touched down (Apollo, Luna, Surveyor, and Chang'e-3 sites) is important for determining landing hazard criteria for future missions. Additionally, assessing the distribution of boulders can address broader science issues, e.g., how far craters distribute boulders and how this distribution varies as a function of crater size and age. The availability of new Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) images [1] enables the use of boulder size- and range frequency distributions for a variety of purposes [2-6]. Boulders degrade over time and primarily occur around young or fresh craters that are large enough to excavate bedrock. Here we use NAC images to analyze boulder distributions around Cone crater (340 m diameter) at the Apollo 14 site. Cone crater (CC) was selected because it is the largest crater where astronaut surface photography is available for a radial traverse to the rim. Cone crater is young (approximately 29 Ma [7]) relative to the time required to break down boulders [3,8], giving us a data point for boulder range-frequency distributions (BRFDs) as a function of crater age.

  12. 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.

  13. 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.

  14. Orbit-averaged quasilinear diffusion operator in the ion-cyclotron range of frequencies

    Science.gov (United States)

    Belmondo, V.; Bilato, R.; Brambilla, M.; Maj, O.

    2010-11-01

    The absorption of radio-frequency waves in the ion-cyclotron range of frequencies (ICRF) in fusion plasmas is adequately described in the frame of the quasilinear theory. A peculiarity of ICRF heating is to increase the fraction of trapped particles, whose the guiding-center trajectories are typically banana orbits with finite width. One possible way to properly account for the effects due to the finite-width orbits is provided by the orbit-averaged quasilinear theory. Here, we propose a routine for the evaluation of the orbit-averaged quasilinear diffusion tensor, given the the wave fields from the full wave code TORIC. Particular care is taken in the evaluation of the contribution of each wave-particle resonance as well as for the transition between the two regimes of correlated and uncorrelated resonances along the orbit. We discuss the quasilinear diffusion coefficient thus obtained and validate the result by comparing the power deposition profile computed from the orbit-averaged quasilinear operator with the one determined by TORIC. For future applications, a novel algorithm for the calculation of the corresponding Monte Carlo operators is also presented.

  15. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Moiseenko, V.E. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center; Lysoivan, A.I. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center; Kasilov, S.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center; Plyusnin, V.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center

    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 ({omega}<{omega}{sub 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.)).

  17. Establishing a link to given radiated emission limits during extending the frequency range above 1 GHz

    Directory of Open Access Journals (Sweden)

    H. Garbe

    2008-05-01

    Full Text Available Up to now most limits for radiated emission are given as values for the electrical field strength. Battermann, 2007 has shown that the frequency range extension for radiated emission measurements above 1 GHz generates a lot of problems while performing the test on a classical test site as depicted in Fig. 1. This paper will give a motivation to use an other measurand namely the total-radiated-power than electrical field strength by using alternative test sites like reverberation chambers, TEM-waveguides, Fully Anechoic Rooms (FAR etc. Nevertheless most of the existing standards still specify electrical field strength limits. This paper will show how to set the parameters in the given algorithm to establish a link between measured total radiated power and equivalent electrical field values.

  18. Relaxations in metallic glasses investigated by a broad frequency and temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Bedorf, Dennis; Koeppe, Thomas; Hachenberg, Joerg; Samwer, Konrad [I. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Kahl, Annelen [Keck Laboratories MS 138-78 Caltech, Pasadena CA 91125 (United States); Richert, Ranko [Department of Chemistry and Biochemistry, Arizona State University, Tempe AZ 85287-1604 (United States)

    2007-07-01

    We are interested in glassy dynamics and the atomistic processes leading to different relaxations in amorphous materials. To measure the complex elastic constants, two mechanical spectroscopy techniques were employed. The use of a double-paddle-oscillator (DPO) provides sufficient sensitivity to investigate the loss of even thin films. A DPO is driven in eigenfrequency mode at 5.4 kHz and an amorphous metallic film (PdCuSi) is evaporated onto it and measured under UHV conditions. Cooling and heating enables measurements in a broad temperature range with different heating rates. To survey the elastic constants at higher frequencies, an ultrasonic spectroscopy technique in the MHz regime is used. The pulse-echo method is applied to a bulk metallic glass in order to obtain the shear modulus and attenuation by monitoring shear wave propagation. The results are discussed in the framework of the Cooperative Shear Model.

  19. Acoustic absorption measurement of human hair and skin within the audible frequency range.

    Science.gov (United States)

    Katz, B F

    2000-11-01

    Utilizing the two-microphone impedance tube method, the acoustic absorption of human skin and hair is measured in the frequency range 1-6 kHz. Various locations on a number of human subjects are measured to determine if the presence of bone or an air pocket affects the acoustic absorption of human skin. The absorption coefficient of human hair is also measured. Additional techniques are utilized to minimize errors due to sample mounting methods. Techniques are employed to minimize potential errors in sensor and sample locations. The results of these measurements are compared to relevant historical papers on similar investigations. Results for skin measurements compare well with previous work. Measured hair absorption data do not agree with previous work in the area but do coincide with expected trends, which previous works do not.

  20. Studies for the ion cyclotron range of frequency heating in a tokamak fusion experimental device

    Energy Technology Data Exchange (ETDEWEB)

    Saigusa, Mikio [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-02-01

    Ion cyclotron range of frequency heating has been investigated as an efficient additional plasma heating and non-inductive current driving methods in a tokamak type fusion experimental device. At first, an ICRF antenna coupling code was developed for the estimation of the coupling properties of phased antenna array, so that the ICRF antennas were designed for JT-60 and JT-60U ICRF heating systems using the coupling codes. The ICRF heating experiments had been performed in JT-60 and JT-60U. The coupling properties of ICRF antenna, the physics of peripheral plasma and energy confinement by ICRF heating in various heating regimes have been investigated. Next, the Toroidicity induced Alfven Eigen (TAE) mode have been studied using minority ICRF heating for producing energetic ions which can excite TAE mode. The TAE mode could be suppressed by current profile control using current ramp operation and lower hybrid current drive. (author) 74 refs.

  1. Interaction of a relativistic electron beam with radiation in the THz frequency range

    Science.gov (United States)

    Sung, Chieh

    0.5-3 THz range with a maximum of ˜2 kW of peak power in a 200 ns pulse suitable as a seed for an FEL microbuncher. These sources represent the most powerful and the most energetic narrowband THz sources currently reported using nonlinear optical technique to our knowledge. During the FEL microbunching process, the wiggling electrons in the undulator also emit radiation coherently at the resonant frequency; as a result, the THz FEL microbuncher can double as a single pass THz amplifier tunable in the 0.5-3 THz range. It is shown that when seeded with a ˜1 kW THz pulse and driven by an electron beam with a peak current of 60A, a 2 m-long undulator can amplify the radiation power to ˜20MW. The frequency range can be further expanded to up to 9 THz via the High Gain Harmonic Generation (HGHG) FEL configuration. The results of these simulations are used as a guide in designing a single-pass THz FEL microbuncher/amplifier which is currently under construction. In order to study THz microbunching and amplification, several original techniques and diagnostics were also developed. Guiding a THz pulse through a hollow waveguide, filtering a short THz pulse using a Fabry-Perot interferometer and measuring the frequency components using a diffraction grating spectrometer were demonstrated.

  2. 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.

  3. Speckle Reduction in OCT using Massively-Parallel Detection and Frequency-Domain Ranging.

    Science.gov (United States)

    Desjardins, A E; Vakoc, B J; Tearney, G J; Bouma, B E

    2006-05-29

    Speckle noise significantly limits the information content provided by coherent optical imaging methods such as optical coherence tomography and its recent derivative, optical frequency-domain imaging (OFDI). In this paper, we demonstrate a novel OFDI system that simultaneously acquires hundreds of angularly resolved images, which can be compounded to reduce speckle noise. The system comprises an InGaAs line-scan camera and an interferometer, configured so that the elements of the detector array simultaneously capture light spanning a backscattering angular range of 32 degrees. On successive read-outs of the array, the wavelength of the laser source was stepped through a range of 130 nm centered at 1295 nm to concurrently generate 400 angle-resolved OFDI images. A theory of angle-resolved OFDI and the design equations of the system are presented. Incoherent averaging of the angle-resolved data is shown to yield substantial speckle reduction (as high as an 8 dB SNR improvement) in images of a tissue phantom and esophageal tissue ex vivo.

  4. On the effect of topography on surface wave propagation in the ambient noise frequency range

    Science.gov (United States)

    Köhler, Andreas; Weidle, Christian; Maupin, Valérie

    2012-04-01

    Due to the increasing popularity of analyzing empirical Green's functions obtained from ambient seismic noise, more and more regional tomographical studies based on short-period surface waves are published. Results could potentially be biased in mountainous regions where topography is not small compared to the wavelength and penetration depth of the considered waves. We investigate the effect of topography on the propagation of short-period Rayleigh waves empirically by means of synthetic data using a spectral element code and a 3-D model with real topography. We show that topography along a profile through the studied area can result in an underestimation of phase velocities of up to about 0.7% at the shortest investigated period (3 s). Contrary to the expectation that this bias results from the increased surface distance along topography, we find that this error can be estimated by local topographic contrasts in the vicinity of the receiver alone. We discuss and generalize our results by considering topographic profiles through other mountain ranges and find that southern Norway is a good proxy to assess the topography effect. Nevertheless, topographic bias on phase velocity measurements is in general not large enough to significantly affect recovered velocity variations in the ambient noise frequency range.

  5. 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.

  6. An acoustical assessment of pitch-matching accuracy in relation to speech frequency, speech frequency range, age and gender in preschool children

    Science.gov (United States)

    Trollinger, Valerie L.

    This study investigated the relationship between acoustical measurement of singing accuracy in relationship to speech fundamental frequency, speech fundamental frequency range, age and gender in preschool-aged children. Seventy subjects from Southeastern Pennsylvania; the San Francisco Bay Area, California; and Terre Haute, Indiana, participated in the study. Speech frequency was measured by having the subjects participate in spontaneous and guided speech activities with the researcher, with 18 diverse samples extracted from each subject's recording for acoustical analysis for fundamental frequency in Hz with the CSpeech computer program. The fundamental frequencies were averaged together to derive a mean speech frequency score for each subject. Speech range was calculated by subtracting the lowest fundamental frequency produced from the highest fundamental frequency produced, resulting in a speech range measured in increments of Hz. Singing accuracy was measured by having the subjects each echo-sing six randomized patterns using the pitches Middle C, D, E, F♯, G and A (440), using the solfege syllables of Do and Re, which were recorded by a 5-year-old female model. For each subject, 18 samples of singing were recorded. All samples were analyzed by the CSpeech for fundamental frequency. For each subject, deviation scores in Hz were derived by calculating the difference between what the model sang in Hz and what the subject sang in response in Hz. Individual scores for each child consisted of an overall mean total deviation frequency, mean frequency deviations for each pattern, and mean frequency deviation for each pitch. Pearson correlations, MANOVA and ANOVA analyses, Multiple Regressions and Discriminant Analysis revealed the following findings: (1) moderate but significant (p pitches E, F♯, G and A in the study; (2) mean speech frequency also emerged as the strongest predictor of subjects' ability to sing the notes E and F♯; (3) mean speech frequency

  7. Experimental Study of High-Range-Resolution Medical Acoustic Imaging for Multiple Target Detection by Frequency Domain Interferometry

    Science.gov (United States)

    Kimura, Tomoki; Taki, Hirofumi; Sakamoto, Takuya; Sato, Toru

    2009-07-01

    We employed frequency domain interferometry (FDI) for use as a medical acoustic imager to detect multiple targets with high range resolution. The phase of each frequency component of an echo varies with the frequency, and target intervals can be estimated from the phase variance. This processing technique is generally used in radar imaging. When the interference within a range gate is coherent, the cross correlation between the desired signal and the coherent interference signal is nonzero. The Capon method works under the guiding principle that output power minimization cancels the desired signal with a coherent interference signal. Therefore, we utilize frequency averaging to suppress the correlation of the coherent interference. The results of computational simulations using a pseudoecho signal show that the Capon method with adaptive frequency averaging (AFA) provides a higher range resolution than a conventional method. These techniques were experimentally investigated and we confirmed the effectiveness of the proposed method of processing by FDI.

  8. 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.

  9. 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

  10. 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

  11. Blood optical properties at various glucose level values in THz frequency range

    Science.gov (United States)

    Gusev, S. I.; Borovkova, M. A.; Strepitov, M. A.; Khodzitsky, M. K.

    2015-07-01

    the patients. Most biomolecules have characteristic signature frequencies in the terahertz (THz) range, which can reveal their presence and determine the concentration. Therefore, this paper is intended to study the blood optical properties in the THz frequency range in order to determine THz radiation effect on blood. The main aim of this investigation is to determine the effect of blood glucose concentration on the blood optical properties. In the case if blood optical properties vary at different glucose concentrations having a proportional relationship between them, these results will confirm the possibility of development of non-invasive procedures for blood glucose level diagnostics.

  12. 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...

  13. Tuning the Polarization State of Light over a Broad Frequency Range with Metasurfaces

    Science.gov (United States)

    Wang, Mu; Jiang, Shang-Chi; Wang, Zheng-Han; Xiong, Xiang; Peng, Ru-Wen; Nanjing University Team

    Controlling the polarization state, the transmission direction and the phase of light within a confined space is an important issue in optics. By integrating metallic metastructure and dielectric interlayer, it is possible to realize the dispersion-free broadband device on sub-wavelength scale, where the strong response of the metallic structures helps to decrease the device size while the dielectric interlayer helps to eliminate the dispersion simultaneously in both the amplitude and the phase difference of the reflected/transmitted light. As an examples to apply this concept, a broadband quarter-wave plate and a half-wave plate are experimentally demonstrated. By carefully selecting the structural parameters, the polarization state of light can be freely tuned across a broad frequency range, and all of the polarization states on the Poincaré sphere can be realized dispersion free. Some contents of this talk can be found in the following references: [1] S.-C. Jiang, et al., High-efficiency generation of circularly polarized light via symmetry-induced anomalous reflection,Physical Review B 91, 125421 (2015), [2] S.-C. Jiang, et al., Controlling the Polarization State of Light with a Dispersion-Free Metastructure, Physical Review X 4, 021026 (2014), [3] X. Xiong, et al., Metallic stereostructured layer: an approach for broadband polarization state manipulation,Applied Physics Letters 105, 201105 (2014).

  14. Temperature- and frequency-dependent dielectric properties of biological tissues within the temperature and frequency ranges typically used for magnetic resonance imaging-guided focused ultrasound surgery.

    Science.gov (United States)

    Fu, Fanrui; Xin, Sherman Xuegang; Chen, Wufan

    2014-02-01

    This study aimed to obtain the temperature- and frequency-dependent dielectric properties of tissues subjected to magnetic resonance (MR) scanning for MR imaging-guided focused ultrasound surgery (MRgFUS). These variables are necessary to calculate radio frequency electromagnetic fields distribution and specific radio frequency energy absorption rate (SAR) in the healthy tissues surrounding the target tumours, and their variation may affect the efficacy of advanced RF pulses. The dielectric properties of porcine uterus, liver, kidney, urinary bladder, skeletal muscle, and fat were determined using an open-ended coaxial probe method. The temperature range was set from 36 °C to 60 °C; and the frequencies were set at 42.58 (1 T), 64 (1.5 T), 128 (3 T), 170 (4 T), 298 (7 T), 400 (9 T), and 468 MHz (11 T). Within the temperature and frequency ranges, the dielectric constants were listed as follows: uterus 49.6-121.64, liver 44.81-127.68, kidney 37.3-169.26, bladder 42.43-125.95, muscle 58.62-171.7, and fat 9.2327-20.2295. The following conductivities were obtained at the same temperature and frequency ranges: uterus 0.5506-1.4419, liver 0.5174-0.9709, kidney 0.8061-1.3625, bladder 0.6766-1.1817, muscle 0.8983-1.3083, and fat 0.1552-0.2316. The obtained data are consistent with the temperature and frequency ranges typically used in MRgFUS and thus can be used as reference to calculate radio frequency electromagnetic fields and SAR distribution inside the healthy tissues subjected to MR scanning for MRgFUS.

  15. Ion cyclotron range of frequencies heating of plasma with small impurity production

    Science.gov (United States)

    Ohkawa, Tihiro

    1987-01-01

    Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.

  16. GNSS single frequency ionospheric range delay corrections: NeQuick data ingestion technique

    Science.gov (United States)

    Oladipo, O. A.; Schüler, Torben

    2012-11-01

    A study of the performance of the NeQuick model and the Klobuchar model for GNSS single frequency range delay correction on a global scale was done using data for moderate solar activity. In this study NeQuick was used in the way intended for Galileo. This study is to assess the performance of the two models at each ionospheric geographic region during moderate solar activity as previously published studies were concentrated only on high solar activity. The results obtained showed that NeQuick outperformed Klobuchar for the whole year at the three geographical regions of the ionosphere. In terms of monthly root mean square of mismodeling, NeQuick outperformed Klobuchar by 15 TECU or more at low-latitudes, 5 TEC or more at mid-latitudes, and 1 TECU or more at high-latitudes. Also, a study on how the data ingestion technique already developed for NeQuick could be expanded in order to reduce the deviation of NeQuick TEC prediction from observation for a particular day based on the information from the previous day was done. Instead of obtaining a regularly spaced Az grid from monitoring stations spread across the region of interest, we obtained hourly Az coefficients from hourly Az from designated monitoring stations. The obtained hourly Az coefficients were then used to drive NeQuick for the next day at the test stations. The results obtained, in terms of daily RMS of mismodeling, showed a daily maximum improvement of 26.0% at low-latitudes, 54.9% at mid-latitudes, and 41.3% at high-latitudes.

  17. 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.

  18. 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 cleaning...... machines and failure detection in aeronautic structures require that the sensitivity of the microphone is known at frequencies up to 150 kHz. Another area of particular interest is the investigation of the perception mechanisms of ultrasound. In any of these applications, it is of fundamental importance...... to establish a well-defined traceability chain to support the measurement results. In order to extend the frequency range of free-field calibration the measurement system and measurement methods must undergo a series of changes and adaptations including the type of excitation signal, techniques for eliminating...

  19. Effects of the gaseous and liquid water content of the atmosphere on range delay and Doppler frequency

    Science.gov (United States)

    Flock, W. L.

    1981-01-01

    When high precision is required for range measurement on Earth space paths, it is necessary to correct as accurately as possible for excess range delays due to the dry air, water vapor, and liquid water content of the atmosphere. Calculations based on representative values of atmospheric parameters are useful for illustrating the order of magnitude of the expected delays. Range delay, time delay, and phase delay are simply and directly related. Doppler frequency variations or noise are proportional to the time rate of change of excess range delay. Tropospheric effects were examined as part of an overall consideration of the capability of precision two way ranging and Doppler systems.

  20. 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.

  1. HIGH DYNAMIC RANGE OBSERVATIONS OF SOLAR CORONAL TRANSIENTS AT LOW RADIO FREQUENCIES WITH A SPECTRO-CORRELATOR

    Energy Technology Data Exchange (ETDEWEB)

    Hariharan, K.; Ramesh, R.; Kathiravan, C.; Rajalingam, M. [Indian Institute of Astrophysics, Bangalore-560034 (India); Abhilash, H. N., E-mail: khariharan@iiap.res.in [Poornaprajna College, Udupi-576101 (India)

    2016-02-15

    A new antenna system with a digital spectro-correlator that provides high temporal, spectral, and amplitude resolutions has been commissioned at the Gauribidanur Observatory near Bangalore in India. Presently, it is used for observations of the solar coronal transients in the scarcely explored frequency range ≈30–15 MHz. The details of the antenna system, the associated receiver setup, and the initial observational results are reported. Some of the observed transients exhibited quasi-periodicity in their time profiles at discrete frequencies. Estimates of the associated magnetic field strength (B) indicate that B ≈ 0.06–1 G at a typical frequency such as 19.5 MHz.

  2. Wide-frequency range, dynamic matching network and power system for the "Shoelace" radio frequency antenna on the Alcator C-Mod tokamak.

    Science.gov (United States)

    Golfinopoulos, Theodore; LaBombard, Brian; Burke, William; Parker, Ronald R; Parkin, William; Woskov, Paul

    2014-04-01

    A wide-frequency range (50-300 kHz) power system has been implemented for use with a new RF antenna - the "Shoelace" antenna - built to drive coherent plasma fluctuations in the edge of the Alcator C-Mod tokamak. A custom, dynamically tunable matching network allows two commercial 1 kW, 50-Ω RF amplifiers to drive the low-impedance, inductive load presented by the antenna. This is accomplished by a discretely variable L-match network, with 81 independently selected steps available for each of the series and parallel legs of the matching configuration. A compact programmable logic device provides a control system that measures the frequency with better than 1 kHz accuracy and transitions to the correct tuning state in less than 1 ms. At least 85% of source power is dissipated in the antenna across the operational frequency range, with a minimum frequency slew rate of 1 MHz/s; the best performance is achieved in the narrower band from 80 to 150 kHz which is of interest in typical experiments. The RF frequency can be run with open-loop control, following a pre-programmed analog waveform, or phase-locked to track a plasma fluctuation diagnostic signal in real time with programmable phase delay; the amplitude control is always open-loop. The control waveforms and phase delay are programmed remotely. These tools have enabled first-of-a-kind measurements of the tokamak edge plasma system response in the frequency range and at the wave number at which coherent fluctuations regulate heat and particle transport through the plasma boundary.

  3. Human exposure to pulsed fields in the frequency range from 6 to 100 GHz

    Science.gov (United States)

    Laakso, Ilkka; Morimoto, Ryota; Heinonen, Juhani; Jokela, Kari; Hirata, Akimasa

    2017-09-01

    Restrictions on human exposure to electromagnetic waves at frequencies higher than 3-10 GHz are defined in terms of the incident power density to prevent excessive temperature rise in superficial tissue. However, international standards and guidelines differ in their definitions of how the power density is interpreted for brief exposures. This study investigated how the temperature rise was affected by exposure duration at frequencies higher than 6 GHz. Far-field exposure of the human face to pulses shorter than 10 s at frequencies from 6 to 100 GHz was modelled using the finite-difference time-domain method. The bioheat transfer equation was used for thermal modelling. We investigated the effects of frequency, polarization, exposure duration, and depth below the skin surface on the temperature rise. The results indicated limitations in the current human exposure guidelines and showed that radiant exposure, i.e. energy absorption per unit area, can be used to limit temperature rise for pulsed exposure. The data are useful for the development of human exposure guidelines at frequencies higher than 6 GHz.

  4. The effects of frequency range, vowel, dynamic loudness level, and gender on nasalance in amateur and classically trained singers.

    Science.gov (United States)

    Jennings, Jori Johnson; Kuehn, David P

    2008-01-01

    This study addresses two questions: (1) How much nasality is present in classical Western singing? (2) What are the effects of frequency range, vowel, dynamic level, and gender on nasality in amateur and classically trained singers? The Nasometer II 6400 by KayPENTAX (Lincoln Park, NJ) was used to obtain nasalance values from 21 amateur singers and 25 classically trained singers while singing an ascending five-tone scalar passage in low, mid, and high frequency ranges. Each subject sang the scalar passage at both piano and mezzo-forte dynamic loudness levels on each of the five cardinal vowels (/a/, /e/, /i/, /o/, /u/). A repeated mixed-model analysis indicated a significant main effect for the amateur/classically trained distinction, dynamic loudness level, and vowel, but not for frequency range or gender. The amateur singers had significantly higher nasalance scores than classically trained singers in all ranges and on all vowels except /o/. Dynamic loudness level had a significant effect on nasalance for all subject groups except for female majors in the mid- and high-frequency ranges. The vowel, /i/, received significantly higher nasalance than all of the other vowels. Although results of this study show that dynamic loudness level, vowel, and level of training in classical singing have a significant effect on nasality, nasalance scores for most subjects were relatively low. Only six of the subjects, all of whom were amateur singers, had average nasalance scores that could be considered hypernasal (ie, a nasalance average of 22 or above).

  5. Extending IPY Data to a Wider Audience

    Science.gov (United States)

    Turrin, M.; Bell, R. E.; Pfirman, S. L.

    2010-12-01

    Perhaps the most significant IPY contribution to science education was the vast amount of data collected at the polar-regions on Earth systems and processes that was made immediately available to teachers and curriculum developers. Supplementing textbooks with the Internet as an education partner, allowed participating teachers to transform science education through: their use of current data as an integral component of their classroom teaching; their training of students to seek out data as evidence of Earth processes; and their instruction to students on how to validate sources and uses of data. Yet, for every teacher and student who has been part of this successful IPY outreach there are many more who have not been reached, don’t know how to include polar science into their coursework, or don’t comfortably work with data. Our experience with data education projects suggests that to reach the next round of students, teachers, educators and the wider adult population we need to translate this data so it is accessible through carefully constructed activities, simulations, and games. In addition we need to actively seek new partnership and outlet opportunities. The collected measurements tell us that our poles are warming on a human timescale. Using data to tell the story, the unambiguous signal of warming makes it accessible to a much broader audience. Our experience has shown that, for a novice population working with data, the educational effectiveness is significantly enhanced when the signal in the data is strong and the Earth processes are clear. Building upon IPY data and resources, focusing on the Earth’s changing climate, and working with partnerships developed over the last two years, Lamont has put together several new education and outreach collaborations. Our goal is to reach new audiences through: 1) Inventorying, Assessing and Planning - Through an NSF planning grant we are leveraging IPY connections and findings in a Polar Climate Education

  6. Filter-free photonic frequency sextupler operated over a wide range of modulation index

    Science.gov (United States)

    Zhu, Zihang; Zhao, Shanghong; Li, Xuan; Qu, Kun; Lin, Tao

    2017-05-01

    An integrated dual-polarization modulator is proposed to generate frequency-sextupled microwave signal without an optical filter. The dual-polarization modulator can achieve even-order optical sidebands suppression modulation along the orthogonal polarization directions with different modulation index. By properly adjusting the power relationship of the orthogonal polarization directions, two optical first-order sidebands will cancel each other out. Thus, a pure frequency-sextupled signal with an optical sideband suppression ratio (OSSR) exceeding 38 dB and a radio frequency spurious suppression ratio (RFSSR) higher than 32 dB is generated, which match well with the theoretical analysis. Since there is no requirement to carefully adjust the modulation index to achieve correct operation of the sextupler, it is much easy to implement. Furthermore, it is also proved to be valid that even if the extinction ratios of the MZMs, the polarization angle of the polarizer, and the direct current (DC) bias phase shift deviate from the ideal values to a certain degree, the performance of the generated frequency-sextupled microwave signal is still acceptable.

  7. 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...

  8. Study on the resolution improvement of a range finder using the chaotic frequency characteristics of a laser diode

    Science.gov (United States)

    Saito, Takahiro; Maehara, Shinya; Doi, Kohei; Sato, Takashi; Ohdaira, Yasuo; Sakamoto, Shuichi; Ohkawa, Masashi

    2017-06-01

    An optical range finder system that relies on laser diodes' frequency noise, instead of intensity or frequency modulations, and its improvement in resolution are reported. The distance to the target is measured by calculating the cross-correlation of two signals reflected from the target and reference mirrors. These two signals are converted from the laser diodes' frequency noise signals by frequency/intensity converters, such as a Fabry-Perot etalon. We obtained the distance to the target by checking time lags between the target and reference beams at the highest correlation coefficient. We also measured the change in the correlation coefficient around the peak sampling point by adjusting the reference-path length, achieving a resolving power of ±3 mm.

  9. 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.

  10. Measurement of Ion Motional Heating Rates over a Range of Trap Frequencies and Temperatures

    CERN Document Server

    Bruzewicz, C D; Chiaverini, J

    2014-01-01

    We present measurements of the motional heating rate of a trapped ion at different trap frequencies and temperatures between $\\sim$0.6 and 1.5 MHz and $\\sim$4 and 295 K. Additionally, we examine the possible effect of adsorbed surface contaminants with boiling points below $\\sim$105$^{\\circ}$C by measuring the ion heating rate before and after locally baking our ion trap chip under ultrahigh vacuum conditions. We compare the heating rates presented here to those calculated from available electric-field noise models. We can tightly constrain a subset of these models based on their expected frequency and temperature scaling interdependence. Discrepancies between the measured results and predicted values point to the need for refinement of theoretical noise models in order to more fully understand the mechanisms behind motional trapped-ion heating.

  11. Effects of laser frequency chirp on modal noise in short-range radio over multimode fiber links

    DEFF Research Database (Denmark)

    Visani, Davide; Tartarini, Giovanni; Petersen, Martin Nordal

    2010-01-01

    An important effect of the frequency chirp of the optical transmitter in radio over multimode fiber links is put into evidence experimentally and modeled theoretically for the first time, to our knowledge. This effect can have an important impact in short-range connections, where, although...

  12. 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...

  13. Aerial low-frequency hearing in captive and free-ranging harbour seals (Phoca vitulina) measured using auditory brainstem responses

    NARCIS (Netherlands)

    Lucke, K.; Hastie, Gordon D.; Ternes, Kerstin; McConnell, Bernie; Moss, Simon; Russell, Deborah J.F.; Weber, Heike; Janik, Vincent M.

    2016-01-01

    The hearing sensitivity of 18 free-ranging and 10 captive harbour seals (Phoca vitulina) to aerial sounds was measured in the presence of typical environmental noise through auditory brainstem response measurements. A focus was put on the comparative hearing sensitivity at low frequencies. Low-

  14. CMOS radio frequency circuits for short-range direct-conversion receivers

    OpenAIRE

    Kaukovuori, Jouni

    2008-01-01

    The research described in this thesis is focused on the design and implementation of radio frequency (RF) circuits for direct-conversion receivers. The main interest is in RF front-end circuits, which contain low-noise amplifiers, downconversion mixers, and quadrature local oscillator signal generation circuits. Three RF front-end circuits were fabricated in a short-channel CMOS process and experimental results are presented. A low-noise amplifier (LNA) is typically the first amplifying b...

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

    OpenAIRE

    Michael P. Murray; Joel Siderius

    2018-01-01

    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. Res...

  16. Full-range swept source optical coherence tomography based on carrier frequency by transmissive dispersive optical delay line.

    Science.gov (United States)

    Wu, Tong; Ding, Zhihua; Wang, Chuan; Chen, Minghui

    2011-12-01

    A high speed swept source optical coherence tomography (SS-OCT) system capable of full-range imaging is presented. Wave-number carrier frequency is introduced into the spectral interference signal by a transmissive dispersive optical delay line (TDODL). High carrier frequency in the spectral interference signal corresponding to an equivalent distance-shift is exploited to obtain full-range OCT imaging. Theoretical development is conducted with the instantaneous coherence function introduced for a complete description of a spectral interference signal. Performance advantage of the TDODL-based method over the conventional approach where only one side (positive or negative path length difference) is used for imaging to avoid overlaying mirror artifacts is confirmed by the measured envelopes of spectral interference signal. Feasibility of the proposed method for full-range imaging is validated in a custom-built SS-OCT system by in vivo imaging of a biological sample.

  17. 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.

  18. Study of transmission line attenuation in broad band millimeter wave frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Pandya, Hitesh Kumar B. [ITER-India, IPR, Gandhinagar, Gujarat (India); Austin, M. E. [Institute for Fusion Studies, the University of Texas at Austin, Austin, Texas (United States); Ellis, R. F. [Laboratory for Plasma and Fusion Energy Studies, University of Maryland, College Park, Maryland 20742 (United States)

    2013-10-15

    Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

  19. Range Detection of the Extremely Low-Frequency Magnetic Field Produced by Laptop's AC Adapter

    Science.gov (United States)

    Brodić, Darko; Amelio, Alessia

    2017-02-01

    Human exposure to extremely low frequency magnetic field represents a risk to their health. This paper takes into consideration the level of an extremely low-frequency magnetic field between 30 and 300 Hz emitted by an AC laptop adapter. The experiment consists of testing 17 different AC adapters for laptops. During the testing, laptops are operated in a normal operating conditions as well as under heavy load. The magnetic field measurement is conducted in the area around the AC adapter. Obtained data is evaluated according to the critical level of the magnetic field proposed by safety standards. Furthermore, data is classified by a K-medians method in order to determine the critical levels of the magnetic field exposure in the nearby area of the AC adapter. Obtained classifications are evaluated according to safety standards, giving a critical analysis of magnetic field areas at risk. Due to emission of a very strong magnetic field in certain areas, a recommendation for safety use of the AC adapter is proposed.

  20. Study of transmission line attenuation in broad band millimeter wave frequency range.

    Science.gov (United States)

    Pandya, Hitesh Kumar B; Austin, M E; Ellis, R F

    2013-10-01

    Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

  1. Dynamic stiffness of chemically and physically ageing rubber vibration isolators in the audible frequency range. Part 1: constitutive equations

    Science.gov (United States)

    Kari, Leif

    2017-09-01

    The constitutive equations of chemically and physically ageing rubber in the audible frequency range are modelled as a function of ageing temperature, ageing time, actual temperature, time and frequency. The constitutive equations are derived by assuming nearly incompressible material with elastic spherical response and viscoelastic deviatoric response, using Mittag-Leffler relaxation function of fractional derivative type, the main advantage being the minimum material parameters needed to successfully fit experimental data over a broad frequency range. The material is furthermore assumed essentially entropic and thermo-mechanically simple while using a modified William-Landel-Ferry shift function to take into account temperature dependence and physical ageing, with fractional free volume evolution modelled by a nonlinear, fractional differential equation with relaxation time identical to that of the stress response and related to the fractional free volume by Doolittle equation. Physical ageing is a reversible ageing process, including trapping and freeing of polymer chain ends, polymer chain reorganizations and free volume changes. In contrast, chemical ageing is an irreversible process, mainly attributed to oxygen reaction with polymer network either damaging the network by scission or reformation of new polymer links. The chemical ageing is modelled by inner variables that are determined by inner fractional evolution equations. Finally, the model parameters are fitted to measurements results of natural rubber over a broad audible frequency range, and various parameter studies are performed including comparison with results obtained by ordinary, non-fractional ageing evolution differential equations.

  2. 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

    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...... 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...

  3. 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

  4. Frequency and fitness consequences of bacteriophage φ6 host range mutations.

    Directory of Open Access Journals (Sweden)

    Brian E Ford

    Full Text Available Viruses readily mutate and gain the ability to infect novel hosts, but few data are available regarding the number of possible host range-expanding mutations allowing infection of any given novel host, and the fitness consequences of these mutations on original and novel hosts. To gain insight into the process of host range expansion, we isolated and sequenced 69 independent mutants of the dsRNA bacteriophage Φ6 able to infect the novel host, Pseudomonas pseudoalcaligenes. In total, we found at least 17 unique suites of mutations among these 69 mutants. We assayed fitness for 13 of 17 mutant genotypes on P. pseudoalcaligenes and the standard laboratory host, P. phaseolicola. Mutants exhibited significantly lower fitnesses on P. pseudoalcaligenes compared to P. phaseolicola. Furthermore, 12 of the 13 assayed mutants showed reduced fitness on P. phaseolicola compared to wildtype Φ6, confirming the prevalence of antagonistic pleiotropy during host range expansion. Further experiments revealed that the mechanistic basis of these fitness differences was likely variation in host attachment ability. In addition, using computational protein modeling, we show that host-range expanding mutations occurred in hotspots on the surface of the phage's host attachment protein opposite a putative hydrophobic anchoring domain.

  5. 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.

  6. 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.

  7. Range-resolved interferometric signal processing using sinusoidal optical frequency modulation.

    Science.gov (United States)

    Kissinger, Thomas; Charrett, Thomas O H; Tatam, Ralph P

    2015-04-06

    A novel signal processing technique using sinusoidal optical frequency modulation of an inexpensive continuous-wave laser diode source is proposed that allows highly linear interferometric phase measurements in a simple, self-referencing setup. Here, the use of a smooth window function is key to suppress unwanted signal components in the demodulation process. Signals from several interferometers with unequal optical path differences can be multiplexed, and, in contrast to prior work, the optical path differences are continuously variable, greatly increasing the practicality of the scheme. In this paper, the theory of the technique is presented, an experimental implementation using three multiplexed interferometers is demonstrated, and detailed investigations quantifying issues such as linearity and robustness against instrument drift are performed.

  8. Magneto-dielectric properties of doped ferrite based nanosized ceramics over very high frequency range

    Directory of Open Access Journals (Sweden)

    Ashish Saini

    2016-06-01

    Full Text Available In the present study, indium doped nano sized nickel zinc cobalt based ferrite ceramics with composition Ni0.5Zn0.3Co0.2InxFe2-xO4 (x = 0.2 and 0.4 were synthesized by a co-precipitation technique. Powdered sample has been pre-sintered at 800 °C, pressed into toroids and finally sintered at 1000 °C. The single phase formation of the presintered powder has been confirmed by X ray diffraction (XRD. The average particle size of the presintered powder has been estimated by field emission scanning electron microscope (FESEM and found to be about ~60 nm for x = 0.2 and ~80 nm at x = 0.4. The electromagnetic characterization has been made using vector network analyzer. High value of permeability (17.3 and 15.2 for x = 0.2 and 0.4 respectively with low magnetic loss tangent of 10−1 order were obtained. Permittivity of 8.2 and 10, and dielectric loss tangent of the order of 10−2 were also achieved. With the measured electromagnetic parameters, miniaturization factor of 12.32 and normalized characteristic impedance close to unity (1.23 were obtained up to 100 MHz frequency. These fascinating parameters definitely propose Ni0.5Zn0.3Co0.2In0.4Fe1.6O4 ceramics as a substrate material for miniaturized antenna in very high frequency band. Possible reasons and mechanisms of electromagnetic properties for different concentrations of indium are discussed in the paper.

  9. Low-frequency source for very long-range underwater communication.

    Science.gov (United States)

    Mosca, Frédéric; Matte, Guillaume; Shimura, Takuya

    2013-01-01

    Very long-range underwater acoustic communication (UAC) is crucial for long cruising (>1000 km) autonomous underwater vehicles (AUVs). Very long-range UAC source for AUV must exhibit high electro-acoustic efficiency (>60%) and compactness. This paper describes the Janus-Hammer Bell (JHB) transducer that has been designed for this purpose and meets those requirements. The transducer works on the 450-550 Hz bandwidth and reaches source level above 200 dB (ref. 1 μPa at 1 m) with 1 kW excitation and full immersion capability. JHB source has been used for communication experiments by the Japanese institute for marine technology (Japan Agency for Marine-Earth Science and Technology) achieving a baud rate of 100 bits/s at 1000 km.

  10. Properties of frequency distribution of Pc5-range pulsations observed with the Ekaterinburg decameter radar in the nightside ionosphere

    Science.gov (United States)

    Chelpanov, Maksim A.; Mager, Olga V.; Mager, Pavel N.; Klimushkin, Dmitri Yu.; Berngardt, Oleg I.

    2018-01-01

    A statistical study of waves in the magnetosphere registered with the midlatitude coherent decameter radar located near Ekaterinburg (EKB), Russia is presented. The radar monitors ionospheric flow velocities whose small-scale variations are evoked by magnetosphere ultra low frequency (ULF) waves of Pc5-range. Data from 16 events observed during 7 months in 2014 and 2015 underwent wavelet analysis. Frequencies of the oscillating components were compared with Alfvén eigenfrequencies, which were inferred from THEMIS and Van Allen spacecraft data. The comparison showed that only a minor part of the oscillations registered with the radar in the nightside ionosphere could be attributed to the Alfvén mode. A majority of the waves have lower frequencies, which do not show dependence on Alfvén eigenfrequency of a field line.

  11. 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.

  12. Impact of major and minor mode on EEG frequency range activities of music processing as a function of expertise.

    Science.gov (United States)

    Jenni, Raoul; Oechslin, Mathias S; James, Clara E

    2017-04-24

    Processing western tonal music may yield distinct brain responses depending on the mode of the musical compositions. Although subjective feelings in response to major and minor mode are well described, the underlying brain mechanisms and their development with increasing expertise have not been thoroughly examined. Using high-density electroencephalography, the present study investigated neuronal activities in the frequency domain in response to polyphone musical compositions in major and minor mode in non-musicians, amateurs and experts. During active listening decrease of theta- and gamma-frequency range activities occurred with increasing expertise in right posterior regions, possibly reflecting enhanced processing efficiency. Moreover, minor and major compositions distinctively modulated synchronization of neuronal activities in high frequency ranges (beta and gamma) in frontal regions, with increased activity in response to minor compositions in musicians and in experts in particular. These results suggest that high-frequency electroencephalographic (EEG) activities carry information about musical mode, showing gradual increase of processing efficiency and sensitivity with musical expertise. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. 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.

  14. SmEdA vibro-acoustic modelling in the mid-frequency range including the effect of dissipative treatments

    Science.gov (United States)

    Hwang, H. D.; Maxit, L.; Ege, K.; Gerges, Y.; Guyader, J.-L.

    2017-04-01

    Vibro-acoustic simulation in the mid-frequency range is of interest for automotive and truck constructors. The dissipative treatments used for noise and vibration control such as viscoelastic patches and acoustic absorbing materials must be taken into account in the problem. The Statistical modal Energy distribution Analysis (SmEdA) model consists in extending Statistical Energy Analysis (SEA) to the mid-frequency range by establishing power balance equations between the modes of the different subsystems. The modal basis of uncoupled-subsystems that can be estimated by the finite element method in the mid-frequency range is used as input data. SmEdA was originally developed by considering constant modal damping factors for each subsystem. However, this means that it cannot describe the local distribution of dissipative materials. To overcome this issue, a methodology is proposed here to take into account the effect of these materials. This methodology is based on the finite element models of the subsystems that include well-known homogenized material models of dissipative treatments. The Galerkin method with subsystem normal modes is used to estimate the modal damping loss factors. Cross-modal coupling terms which appear in the formulation due to the dissipative materials are assumed to be negligible. An approximation of the energy sharing between the subsystems damped by dissipative materials is then described by SmEdA. The different steps of the method are validated experimentally by applying it to a laboratory test case composed of a plate-cavity system with different configurations of dissipative treatments. The comparison between the experimental and the simulation results shows good agreement in the mid-frequency range.

  15. 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.

  16. Coastal Resource Management in the Wider Caribbean : Resilience ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    1 janv. 2010 ... Coastal Resource Management in the Wider Caribbean : Resilience, Adaptation, and Community Diversity. Couverture du livre Coastal Resource Management in the Wider Caribbean : Resilience, Adaptation, and. Directeur(s) : Yvan Breton, David Brown, Brian Davy, Milton Haughton et Luis Ovares.

  17. A crossover trial comparing wide dynamic range compression and frequency compression in hearing aids for tinnitus therapy.

    Science.gov (United States)

    Hodgson, Shirley-Anne; Herdering, Regina; Singh Shekhawat, Giriraj; Searchfield, Grant D

    2017-01-01

    It has been suggested that frequency lowering may be a superior tinnitus reducing digital signal processing (DSP) strategy in hearing aids than conventional amplification. A crossover trial was undertaken to determine if frequency compression (FC) was superior to wide dynamic range compression (WDRC) in reducing tinnitus. A 6-8-week crossover trial of two digital signal-processing techniques (WDRC and 2 WDRC with FC) was undertaken in 16 persons with high-frequency sensorineural hearing loss and chronic tinnitus. WDRC resulted in larger improvements in Tinnitus Functional Index and rating scale scores than WDRC with FC. The tinnitus improvements obtained with both processing types appear to be due to reduced hearing handicap and possibly decreased tinnitus audibility. Hearing aids are useful assistive devices in the rehabilitation of tinnitus. FC was very successful in a few individuals but was not superior to WDRC across the sample. It is recommended that WDRC remain as the default first choice tinnitus hearing aid processing strategy for tinnitus. FC should be considered as one of the many other options for selection based on individual hearing needs. Implications of Rehabilitation Hearing aids can significantly reduce the effects of tinnitus after 6-8 weeks of use. Addition of frequency compression digital signal processing does not appear superior to standard amplitude compression alone. Improvements in tinnitus were correlated with reductions in hearing handicap.

  18. Frequency tripled 1542 nm telecom laser diode stabilized to iodine hyperfine line in the 10-15 range

    CERN Document Server

    Philippe, Charles; Holleville, David; Lours, Michel; Minh-Pham, Tuam; Hrabina, Jan; Burck, Frederic Du; Wolf, Peter; Acef, Ouali

    2016-01-01

    We report on telecom laser frequency stabilization to narrow iodine hyperfine line in the green range of the optical domain, after a frequency tripling process using two nonlinear PPLN crystals. We have generated up to 300 mW optical power in the green (P3w), from 800 mW of infrared power (Pw). This result corresponds to an optical conversion efficiency eta= P3w/Pw ~ 36 %. To our knowledge, this is the best value ever demonstrated for a CW frequency tripling process. We have used a narrow linewidth iodine hyperfine line (component a1 of the 127I2 R 35 (44-0) line) to stabilize the IR laser yielding to frequency stability of 4.8x10-14 t-1/2 with a minimum of 6x10-15 reached after 50 s of integration time. The whole optical setup is very compact and mostly optically fibered. This approach opens the way for efficient and elegant architecture development for space applications as one of several potential uses.

  19. Prominent facilitation at beta and gamma frequency range revealed with physiological calcium concentration in adult mouse piriform cortex in vitro.

    Directory of Open Access Journals (Sweden)

    Marie Gleizes

    Full Text Available Neuronal activity is characterized by a diversity of oscillatory phenomena that are associated with multiple behavioral and cognitive processes, yet the functional consequences of these oscillations are not fully understood. Our aim was to determine whether and how these different oscillatory activities affect short-term synaptic plasticity (STP, using the olfactory system as a model. In response to odorant stimuli, the olfactory bulb displays a slow breathing rhythm as well as beta and gamma oscillations. Since the firing of olfactory bulb projecting neurons is phase-locked with beta and gamma oscillations, structures downstream from the olfactory bulb should be driven preferentially at these frequencies. We examined STP exhibited by olfactory bulb inputs in slices of adult mouse piriform cortex maintained in vitro in an in vivo-like ACSF (calcium concentration: 1.1 mM. We replaced the presynaptic neuronal firing rate by repeated electrical stimulation (frequency between 3.125 and 100 Hz applied to the lateral olfactory tract. Our results revealed a considerable enhancement of postsynaptic response amplitude for stimulation frequencies in the beta and gamma range. A phenomenological model of STP fitted to the data suggests that the experimental results can be explained by the interplay between three mechanisms: a short-term facilitation mechanism (time constant ≈160 msec, and two short-term depression mechanisms (recovery time constants <20 msec and ≈140 msec. Increasing calcium concentration (2.2 mM resulted in an increase in the time constant of facilitation and in a strengthening of the slowest depression mechanism. As a result, response enhancement was reduced and its peak shifted toward the low beta and alpha ranges while depression became predominant in the gamma band. Using environmental conditions corresponding to those that prevail in vivo, our study shows that STP in the lateral olfactory tract to layer Ia synapse allows

  20. Multifunctional photoacoustic signals detected by P(VDF/TrFE) film sensor with a wide range of frequency

    Science.gov (United States)

    Ishihara, M.; Hirasawa, T.; Tsujita, K.; Kitagaki, M.; Bansaku, I.; Fujita, M.; Kikuchi, M.

    2011-03-01

    Photoacoustics has been widely studied as a combined imaging modality of both optical and acoustical methods. The merits of the photoacoustic imaging are realizing the full potentials of pulsed laser-tissue interaction. As the photoacoustic waves can be induced at chromophores by pulsed lased irradiation through a thermoelastic process, it covers a wide range of frequency. In order to take advantages of the wide range frequency characteristics, we employed not PZT, but piezoelectronic copolymer film, P(VDF/TrFE) film, with various thickness ranging from 20 to 100 μm as photoacoustic transducers. Because blood vessels play a key role in homeostasis, we experimentally demonstrated blood vessels phantom using second harmonic generation of Q-switched Nd:YAG laser and Ti:sapphire nanosecond laser pulses through optical fiber transmission. The detected photoacoustic waveforms showed distinctive time-of-flight signals. The photoacoustic signals were sensitive to temperature, absorption coefficients of chromophores, and diameters of the phantom vessels. Hemoglobin oxygen saturation could be easily derived from the multi wavelength photoacoustic signals using differential optical absorption characteristics. These results proved the functional quantitative photoacoustic imaging using the signal characteristics. A multivariate photoacoustic imaging approach must be promising to convenient diagnosis.

  1. Vibroacoustics of the piano soundboard: (Non)linearity and modal properties in the low- and mid-frequency ranges

    Science.gov (United States)

    Ege, Kerem; Boutillon, Xavier; Rébillat, Marc

    2013-03-01

    The piano soundboard transforms the string vibration into sound and therefore, its vibrations are of primary importance for the sound characteristics of the instrument. An original vibro-acoustical method is presented to isolate the soundboard nonlinearity from that of the exciting device (here: a loudspeaker) and to measure it. The nonlinear part of the soundboard response to an external excitation is quantitatively estimated for the first time, at ≈-40 dB below the linear part at the ff nuance. Given this essentially linear response, a modal identification is performed up to 3 kHz by means of a novel high resolution modal analysis technique [K. Ege, X. Boutillon, B. David, High-resolution modal analysis, Journal of Sound and Vibration 325 (4-5) (2009) 852-869]. Modal dampings (which, so far, were unknown for the piano in this frequency range) are determined in the mid-frequency domain where FFT-based methods fail to evaluate them with an acceptable precision. They turn out to be close to those imposed by wood. A finite-element modelling of the soundboard is also presented. The low-order modal shapes and the comparison between the corresponding experimental and numerical modal frequencies suggest that the boundary conditions can be considered as blocked, except at very low frequencies. The frequency-dependency of the estimated modal densities and the observation of modal shapes reveal two well-separated regimes. Below ≈1 kHz, the soundboard vibrates more or less like a homogeneous plate. Above that limit, the structural waves are confined by ribs, as already noticed by several authors, and localised in restricted areas (one or a few inter-rib spaces), presumably due to a slightly irregular spacing of the ribs across the soundboard.

  2. 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.

  3. Range of motion and stroke frequency differences between manual wheelchair propulsion and pushrim-activated power-assisted wheelchair propulsion.

    Science.gov (United States)

    Corfman, Thomas A; Cooper, Rory A; Boninger, Michael L; Koontz, Alicia M; Fitzgerald, Shirley G

    2003-01-01

    The objective of this study was to examine the use and efficacy of a pushrim-activated power-assist wheelchair (PAPAW) in the reduction of upper extremity range of motion (ROM) and stroke frequency in manual wheelchair users. Ten manual wheelchair users were evaluated using a repeated-measures design with and without the use of a PAPAW for maximum ROM of shoulder flexion/extension, abduction/adduction, internal/external rotation, and horizontal flexion/extension; elbow flexion/extension; wrist flexion/extension, supination/pronation, and ulnar/radial deviation; and stroke frequency. Participants propelled a Quickie 2 manual wheelchair configured as a PAPAW and their own wheelchair on a computer-controlled dynamometer at 3 different resistance levels and 2 different speeds. The use of the PAPAW significantly (P wrist flexion/extension and ulnar/radial deviation for many speed and resistance combinations. Univariate analysis revealed that stroke frequency was unaltered in all cases. These findings provide the foundation for studying the utility of the PAPAW in reducing the risk of upper limb injury and neuropathy in the manual wheelchair user population.

  4. The Digital Simulation of Synchronous Motors Fed by Voltage-Source Inverters Over Wide Speed and Frequency Ranges

    Science.gov (United States)

    Rowihal, Said Soliman

    Both voltage-source and current-source inverters are widely used for supplying three-phase power to induction motor drives, each having their advantages and disadvantages. For high power drives and applications requiring accurate speed and tracking coordination, the synchronous motors are the optimum choice. For constant speed applications of synchronous motor drives, current-source inverters tend to be favored as the motor can usually be operated in the overexcited leading power factor region, thus providing the inverter with sufficient electro-motive force to allow natural commutation. Generally speaking low speed operation of synchronous motors is not satisfactory from naturally commutated current-source inverters. To provide a dynamic range of speed and frequency would require expensive control circuitry and complicates the performance of the drive. The advantage of the voltage-source inverter for the wide range of speed and frequency control herein envisaged is that forced commutation is employed throughout the range and the commutating circuits have been well developed and established. On balance, voltage-source inverters represent a viable compromise for variable-speed three -phase synchronous motor drives including start-up. To investigate the transient response of the voltage -source fed-synchronous motor drives, a digital computer program is developed. The program is based on two models --machine model and inverter model. The machine is represented by a detailed two-axis model which includes the effects due to saliency, damper windings, and machine resistances. The inverter model represents a forced-commutated voltage-source inverter assuming ideal switching devices (thyristors and diodes). To cope with the wide variations of power factor during start-up, a thyristor with a reverse connected parallel diode are integrated as a bidirectional switch. The digital program provides the machine variables of interest (phase currents, field current, damper winding

  5. High-sensitivity operation of single-beam optically pumped magnetometer in a kHz frequency range

    Science.gov (United States)

    Savukov, I.; Kim, Y. J.; Shah, V.; Boshier, M. G.

    2017-03-01

    Optically pumped magnetometers (OPM) can be used in various applications, from magnetoencephalography to magnetic resonance imaging and nuclear quadrupole resonance (NQR). OPMs provide high sensitivity and have the significant advantage of non-cryogenic operation. To date, many magnetometers have been demonstrated with sensitivity close to 1 fT, but most devices are not commercialized. Most recently, QuSpin developed a model of OPM that is low cost, high sensitivity, and convenient for users, which operates in a single-beam configuration. Here we developed a theory of single-beam (or parallel two-beam) magnetometers and showed that it is possible to achieve good sensitivity beyond their usual frequency range by tuning the magnetic field. Experimentally we have tested and optimized a QuSpin OPM for operation in the frequency range from DC to 1.7 kHz, and found that the performance was only slightly inferior despite the expected decrease due to deviation from the spin-exchange relaxation-free regime.

  6. Viscoelastic behavior over a wide range of time and frequency in tin alloys: SnCd and SnSb

    Energy Technology Data Exchange (ETDEWEB)

    Quackenbush, J.; Brodt, M.; Lakes, R.S. [Univ. of Iowa, Iowa City, IA (United States)

    1996-08-01

    All materials exhibit some viscoelastic response, which can manifest itself as creep, relaxation, or, if the load is sinusoidal in time, a phase angle {delta} between stress and strain. Recently, a study of pure elements with low melting points, Cd, In, Pb, and Sn disclosed that cadmium exhibited a substantial loss tangent of 0.03 to 0.04 over much of the audio range of frequencies, combined with a moderate stiffness G = 20.7 GPa. Lead, by contrast, exhibited tan {delta} of 0.005 to 0.016 in the audio range. Indium exhibited a high loss tangent exceeding 0.1 at very low frequency. A eutectic alloy of indium and tin was found to exhibit substantial damping exceeding 0.1 below 0.1 Hz, and this alloy was used to make a composite exhibiting high stiffness and high damping. It is the purpose of this communication to present viscoelastic properties of two additional low melting point alloys, SnCd and SnSb. Both InSn and SnSb are used as solders. Although the melting point of Sb is 630.74 C, T{sub H} > 0.55 at ambient temperature for the alloy of SnSb (95 wt% Sn/5 wt% Sb) which melts near 240 C. Eutectic SnCd melts at 177 C so T{sub H} {approx} 0.65 at room temperature.

  7. Spatial distribution of spectral parameters of high latitude geomagnetic disturbances in the Pc5/Pi3 frequency range

    Directory of Open Access Journals (Sweden)

    N. V. Yagova

    2010-09-01

    Full Text Available We analyze spectral parameters of the geomagnetic disturbances within the 1–4 mHz (Pc5/Pi3 frequency range for 29 observatories from polar to auroral latitudes. The main object of this study is the broadband (noise background under quiet and moderately disturbed conditions. To obtain a quantitative description of background high-latitude long period ULF activity the log-log dependence of the spectral power on frequency is expanded over Legendre polynomials, and the coefficients of this expansion (spectral moments are used to describe the most common features of these spectra. Not only the spectral power, but also the spectral slope and higher spectral moments, averaged over relatively long time intervals, demonstrate a systematic dependence on corrected geomagnetic (CGM latitude, Φ, and magnetic local time, MLT. The 2-D distributions of the spectral moments in Φ-MLT coordinates are characterized by existence of structures, narrow in latitude and extended in MLT, which can be attributed to the projections of different magnetospheric domains. Spatio-temporal distributions of spectral power of elliptically (P-component and randomly (N-component polarized signal are similar, but not identical. The N-component contribution to the total signal becomes non-negligible in regions with a high local activity, such as the auroral oval and dayside polar cusp. The spectral slope indicates a larger relative contribution of higher frequencies upon the latitude decrease, probably, as a result of the resonant effects in the ULF noise. The higher spectral moments are also controlled mostly by CGM latitude and MLT and are fundamentally different for the polarized and non-polarized components. This study is a step towards the construction of an empirical model of the ULF wave power in Earth's magnetosphere.

  8. Learning the skills of flexible sigmoidoscopy - the wider perspective.

    Science.gov (United States)

    Kneebone, R L; Nestel, D; Moorthy, K; Taylor, P; Bann, S; Munz, Y; Darzi, A

    2003-11-01

    Nurse-led gastrointestinal endoscopy is a priority clinical area in the UK. Endoscopic procedures are challenging to learn, requiring a combination of technical competence (manipulating a flexible endoscope and interpreting the findings) and interpersonal skills (engaging effectively with a conscious patient who is frequently apprehensive). This paper explores the potential of an innovative, scenario-based approach which links a simulated patient with a computer-driven virtual reality (VR) training device for flexible sigmoidoscopy. Within this safe yet realistic quasi-clinical environment, learners carry out the procedure while interacting with the 'patient'. Communication skills are assessed by simulated patients, while quantitative performance data relating to the procedure is generated automatically by the VR simulator. This pilot study took place within a nurse practitioner endoscopy course. A mixed methodology combined qualitative and quantitative data (observation and interview studies, communication rating scales and a range of computer-generated output measures from the VR simulator) in a multifaceted evaluation. Seven nurses took part in the study. Participants found the scenarios to be a convincing and powerful learning experience. All experienced high levels of anxiety. Simulated patients identified strengths in participants' communication skills, together with areas for development. Simulator-based practice led to an improvement in objective performance measures. Scenario-based training provides a powerful learning experience, allowing participants to build their technical expertise and apply it within a holistic clinical context without the risk of causing harm. We used this pilot study as a springboard for discussions over wider implications of procedure-based skills training, locating it within the literature on expertise and situated learning.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garaio, E., E-mail: eneko.garayo@ehu.es [Elektrizitatea eta Elektronika Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Collantes, J.M. [Elektrizitatea eta Elektronika Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Garcia, J.A. [Fisika Aplikatua II Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Plazaola, F. [Elektrizitatea eta Elektronika Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Mornet, S. [Institut de Chimie de la Matière Condensée de Bordeaux, UPR 9048 CNRS / Université de Bordeaux, Bordeaux (France); Couillaud, F. [Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS / Université de Bordeaux, Bordeaux (France); Sandre, O., E-mail: olivier.sandre@enscbp.fr [Laboratoire de Chimie des Polymères Organiques, UMR 5629 CNRS / Université de Bordeaux, Bordeaux (France)

    2014-11-15

    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{sup −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{sup −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.

  10. IN MY OPINION: Physics in the wider context

    Science.gov (United States)

    Morris, Andrew

    1999-11-01

    A great range of professionals is involved in physics education. At the heart of it all are teachers in colleges and schools, seeking to inspire the learner and to develop their own pedagogic skill. Funding bodies, senior management teams and government agencies shape the courses they teach. Writers and publishers of textbooks, CD-ROMs and web pages are constantly upgrading materials to attract and retain learners. Laboratory and equipment suppliers plan their next line of products, architects and managers dream of new buildings to replace our Victorian heritage. And, in this age of prescription and regulation, critically important to physics education are the designers of specifications, qualifications and frameworks who determine much of what people learn. Increasingly this army of providers will be joined by broadcasters, museum planners and others. Outside the domain of qualifications, there is a widespread fascination with science, perhaps a growing one. There is strong interest in evolution, genetics and developmental biology, in ecology, earth science and the environment and in the areas of cosmology, particle physics and unified theories. I believe the fascination draws on people's desire to interpret and understand themselves and their surroundings. It is fuelled by the excitement of the ideas underlying science and graphic images that television is able to generate. Paradoxically, discussion of post-16 science education can be dispiriting. Declining numbers of young people choose to study physics, and recruiting first-class teachers of physics is a major issue. Equally important is the broader question of the skills, knowledge and understanding that will be required by everyone in the medium term future. As well as the specialized skills of scientists and engineers, national economies will need higher levels of skill in the advanced technician and management parts of their workforce. There is a dilemma about how to maintain standards, recruitment levels

  11. 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.

  12. Microstrip Antennas with Polarization Diversity across a Wide Frequency Range and Phased Array Antennas for Radar and Satellite Communications

    Science.gov (United States)

    Ho, Kevin Ming-Jiang

    The thesis comprises of 3 projects; an L-band microstrip antenna with frequency agility and polarization diversity, X-band phased array antennas incorporating commercially packaged RFIC phased array chips, and studies for Ku/Ka-band shared aperture antenna array. The first project features the use of commercially packaged RF-MEMS SPDT switches, that boasts of high reliability, high linearity, low losses, hermetically packaged and fully compatible for SMTA processes for mass-assembly and production. Using the switches in a novel manner for the feed network, microstrip antennas with polarization diversity are presented. Frequency agility is achieved with the use of tuning diodes to provide capacitive loading to the antenna element. Additional inductance effects from surface-mounted capacitors, and its impact, is introduced. Theoretical cross-polarization of probe-fed antenna elements is presented for both linear and circular polarized microstrip antennas. Designs and measurements are presented, for microstrip antennas with polarization diversity, wide frequency tuning range, and both features. Replacement of the tuning diodes with commercially-packaged high Q RF MEMS tunable capacitors will allow for significant improvements to the radiation efficiency. In another project, multi-channel CMOS RFIC phased-array receiver chips are assembled in QFN packages and directly integrated on the same multi-layered PCB stack-up with the antenna arrays. Problems of isolation from the PCB-QFN interface, and potential performance degradation on antenna array from the use of commercial-grade laminates for assembly requirements, namely potential scan blindness and radiation efficiency, are presented. Causes for apparent drift of dielectric constant for microstrip circuits, and high conductor losses observed in measurements, are introduced. Finally, studies are performed for the design of a Ku/Ka-Band shared aperture array. Different approaches for developing dual-band shared apertures

  13. Strengthening Coastal Pollution Management in the Wider Caribbean Region

    NARCIS (Netherlands)

    Lavieren, van H.; Metcalfe, C.D.; Drouillard, K.; Sale, P.; Gold-Bouchot, G.; Reid, R.; Vermeulen, L.C.

    2011-01-01

    Control of aquatic pollution is critical for improving coastal zone management and for the conservation of fisheries resources. Countries in the Wider Caribbean Region (WCR) generally lack monitoring capacity and do not have reliable information on the levels and distribution of pollutants,

  14. Casting CurriculumNet wider | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2011-02-02

    Feb 2, 2011 ... The project expanded through a pilot computer network to six rural schools in districts surrounding the hub at NCDC in Kampala. Eventually CurriculumNet will achieve wider use throughout Uganda. As part of the project, representatives from Ugandan educational bodies did participatory assessments to ...

  15. 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.

  16. Dispersion curves of viscoelastic plane waves and Rayleigh surface wave in high frequency range with fractional derivatives

    Science.gov (United States)

    Usuki, Tsuneo

    2013-09-01

    The moduli of conventional elastic structural materials are extended to one of the viscoelastic materials through a modification whereby the dynamic moduli converge to the static moduli of elasticity as the fractional order approaches zero. By plotting phase velocity curves and group velocity curves of plane waves and Rayleigh surface wave for a viscoelastic material (polyvinyl chloride foam), the influence of the fractional order of viscoelasticity is examined. The phase and group velocity curves in the high frequency range were derived for longitudinal, transverse, and Rayleigh waves inherent to the viscoelastic material. In addition, the equation for the phase velocity was mathematically derived on the complex plane, too, and graphically illustrated. A phenomenon was found that, at the moment when the fractional order of the time derivative reaches an integer value 1, the curve on the complex plane becomes completely different, exhibiting snap-through behavior. We examined the mechanism of the snap-through mathematically. Numerical calculation examples were solved, and good agreement was confirmed between the numerical calculation and the analytical expression mentioned above. From the results of the numerical example, regularities were derived for the absolute value of the complex phase and group velocities on the complex plane.

  17. Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

    Directory of Open Access Journals (Sweden)

    Roberta Gomes Carvalho/

    2014-09-01

    Full Text Available The geographical distribution of Aedes albopictus in Brazil was updated according to the data recorded across the country over the last eight years. Countrywide house indexes (HI for Ae. albopictus in urban and suburban areas were described for the first time using a sample of Brazilian municipalities. This mosquito is currently present in at least 59% of the Brazilian municipalities and in 24 of the 27 federal units (i.e., 26 states and the Federal District. In 34 Brazilian municipalities, the HI values for Ae. albopictus were higher than those recorded for Ae. aegypti, reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding the current range of this mosquito species in the Americas are also presented. Nineteen American countries are currently infested and few mainland American countries have not confirmed the occurrence of Ae. albopictus. The large distribution and high frequency of Ae. albopictus in the Americas may become a critical factor in the spread of arboviruses like chikungunya in the new world.

  18. Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

    Science.gov (United States)

    Carvalho, Roberta Gomes; Lourenço-de-Oliveira, Ricardo; Braga, Ima Aparecida

    2014-01-01

    The geographical distribution of Aedes albopictus in Brazil was updated according to the data recorded across the country over the last eight years. Countrywide house indexes (HI) for Ae. albopictus in urban and suburban areas were described for the first time using a sample of Brazilian municipalities. This mosquito is currently present in at least 59% of the Brazilian municipalities and in 24 of the 27 federal units (i.e., 26 states and the Federal District). In 34 Brazilian municipalities, the HI values for Ae. albopictus were higher than those recorded for Ae. aegypti, reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding the current range of this mosquito species in the Americas are also presented. Nineteen American countries are currently infested and few mainland American countries have not confirmed the occurrence of Ae. albopictus. The large distribution and high frequency of Ae. albopictus in the Americas may become a critical factor in the spread of arboviruses like chikungunya in the new world. PMID:25317707

  19. 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.

  20. Brownfields to green fields: Realising wider benefits from practical contaminant phytomanagement strategies.

    Science.gov (United States)

    Cundy, A B; Bardos, R P; Puschenreiter, M; Mench, M; Bert, V; Friesl-Hanl, W; Müller, I; Li, X N; Weyens, N; Witters, N; Vangronsveld, J

    2016-12-15

    Gentle remediation options (GROs) are risk management strategies or technologies involving plant (phyto-), fungi (myco-), and/or bacteria-based methods that result in a net gain (or at least no gross reduction) in soil function as well as effective risk management. GRO strategies can be customised along contaminant linkages, and can generate a range of wider economic, environmental and societal benefits in contaminated land management (and in brownfields management more widely). The application of GROs as practical on-site remedial solutions is still limited however, particularly in Europe and at trace element (typically metal and metalloid) contaminated sites. This paper discusses challenges to the practical adoption of GROs in contaminated land management, and outlines the decision support tools and best practice guidance developed in the European Commission FP7-funded GREENLAND project aimed at overcoming these challenges. The GREENLAND guidance promotes a refocus from phytoremediation to wider GROs- or phyto-management based approaches which place realisation of wider benefits at the core of site design, and where gentle remediation technologies can be applied as part of integrated, mixed, site risk management solutions or as part of "holding strategies" for vacant sites. The combination of GROs with renewables, both in terms of biomass generation but also with green technologies such as wind and solar power, can provide a range of economic and other benefits and can potentially support the return of low-level contaminated sites to productive usage, while combining GROs with urban design and landscape architecture, and integrating GRO strategies with sustainable urban drainage systems and community gardens/parkland (particularly for health and leisure benefits), has large potential for triggering GRO application and in realising wider benefits in urban and suburban systems. Quantifying these wider benefits and value (above standard economic returns) will be

  1. Neurone bioelectric activity under magnetic fields of variable frequency in the range of 0.1-80 Hz

    Science.gov (United States)

    Pérez Bruzón, R. N.; Azanza, María. J.; Calvo, Ana C.; del Moral, A.

    2004-05-01

    Intracellular recordings from single unit molluscan neurones under exposure to ELF-MF (1 mT, 0.1-80 Hz), show that neurone frequency activity, f, decreases with the applied magnetic field frequency, fM, a phenomenon which indicates a frequency-window effect for the neurone membrane response. The HMHW of the window amounts between 2-10 Hz. An explanation of this phenomenon is proposed.

  2. Neurone bioelectric activity under magnetic fields of variable frequency in the range of 0.1-80 Hz

    Energy Technology Data Exchange (ETDEWEB)

    Perez Bruzon, R.N.; Azanza, M.J. E-mail: mjazanza@posta.unizar.es; Calvo, Ana C.; Moral, A. del

    2004-05-01

    Intracellular recordings from single unit molluscan neurones under exposure to ELF-MF (1 mT, 0.1-80 Hz), show that neurone frequency activity, f, decreases with the applied magnetic field frequency, f{sub M}, a phenomenon which indicates a frequency-window effect for the neurone membrane response. The HMHW of the window amounts between 2-10 Hz. An explanation of this phenomenon is proposed.

  3. 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.

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

    Science.gov (United States)

    Urbanczyk, Guillaume; Zhang, Xinjun; Qin, Chengming; Zhao, Yanping; Zhang, Tao; Zhang, Ling; Li, Jiangang; Yuan, Shuai; Chen, Liang; Zhang, Heng; Zhang, Jiahui; Wang, Jianhua; Yang, Xiuda; Qian, Jinping

    2017-10-01

    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.

  5. 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.

  6. Eco-creative training: wider competences profiling session for green design in chemical engineering

    OpenAIRE

    Szewczyk-Zakrzewska, Agnieszka; Avsec, Stanislav

    2015-01-01

    As human populations increase in size, extent, and diversity, natural resource planners and policymakers must address growing concerns about a wide range of environments. To make the best decisions - for people and for nature - they need knowledge, skills and wider competences of creative thinking and decision-making, about how people, industry and natural environments influence each other. The human component of natural resource management became important issue worldwide. All...

  7. A Microbolometer System for Radiation Detection in the THz Frequency Range with a Resonating Cavity Fabricated in the CMOS Technology.

    Science.gov (United States)

    Sesek, Aleksander; Zemva, Andrej; Trontelj, Janez

    2018-02-14

    The THz sensors using microbolometers as a sensing element are reported as one of the most sensitive room-temperature THz detectors suitable for THz imaging and spectroscopic applications. Microbolometer detectors are usually fabricated using different types of the MEMS technology. The patent for the detection system presented in this paper describes a method for microbolometer fabrication using a standard CMOS technology with advanced micromachining techniques. The measured sensitivity of the sensors fabricated by the patented method is 1000 V/W at an optimal frequency and is determined by the performance of a double-dipole antenna and quarter-wavelength resonant cavity. The paper presents a patented method for fabrication of a microbolometer system for radiation detection in the THz frequency range (16). The method is divided into several stages regarding the current silicon micromachining process. Main stages are fabrication of supporting structures for micro bridge, creation of micro cavities and fabrication of Aluminum antenna and Titanium microbolometer. Additional method for encapsulation in the vacuum is described which additionally improves the performance of bolometer. The CMOS technology is utilized for fabrication as it is cost effective and provides the possibility of larger sensor systems integration with included amplification. At other wavelengths (e.g. IR region) thermistors are usually also the receivers with the sensor resistance change provoked by self-heating. In the THz region the energy is received by an antenna coupled to a thermistor. Depending on the specific application requirement, two types of the antenna were designed and used; a narrow-band dipole antenna and a wideband log-periodic antenna. With method described in the paper, the microbolometer detector reaches sensitivities up to 500 V/W and noise equivalent power (NEP) down to 10 pW/√Hz. Additional encapsulation in the vacuum improves its performance at least by a factor of 2

  8. Passive exposure of adult cats to moderate-level tone pip ensembles differentially decreases AI and AII responsiveness in the exposure frequency range.

    Science.gov (United States)

    Pienkowski, Martin; Eggermont, Jos J

    2010-09-01

    Passive exposure of adult animals to a random ensemble of tone pips band limited between 4 and 20 kHz has been shown to suppress neural activity in primary auditory cortex (AI) to sounds in the exposure frequency range. In the long-term (>3 months), the suppressed neurons can be reactivated by frequencies above and below the exposure range, i.e., tonotopic map reorganization occurs. The suppression can be at least partially reversed after a long period of quiet recovery, as the moderate-level exposure does not impair peripheral hearing. Here we exposed adult cats, for 7-13 weeks without interruption, to two different moderate-level tone pip ensembles, in separate experiments. One exposure stimulus consisted of an octave-wide 2-4 kHz band, which overlaps substantially with the cat vocalization range; the other consisted of a pair of third-octave bands centered at 4 and 16 kHz. We again report a decrease in AI responsiveness in the exposure frequency range, irrespective of the exposure stimulus bandwidth or center frequency, and a slow, partial recovery over a 12-week post-exposure window. In contrast to our previous studies, the suppression in both of the present experiments extended well beyond the exposure frequency range. In particular, following the 4 and 16 kHz experimental acoustic environment, AI activity was strongly suppressed not only in response to frequencies close to the two exposure bands, but also in response to frequencies between the bands, i.e., the results resembled those to a single broadband stimulus spanning the 3-18 kHz range. On the other hand, responses in secondary auditory cortex (AII) were suppressed predominantly around 4 and 16 kHz, with little or no suppression in between. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  9. Day workers suffering from a wider range of sleep problems are more likely to experience suicidality

    OpenAIRE

    Matsumoto, Yuuki; Uchimura, Naohisa; Ishida, Tetsuya; Toyomasu, Kouji; Morimatsu, Yoshitaka; Mori, Mihoko; Kushino, Nanae; Hoshiko, Michiko; Ishitake, Tatsuya

    2016-01-01

    Both a higher suicide rate and widespread sleep problems are serious health concerns in Japan when compared with those of other countries. We investigated the relationship between suicidal ideation and sleep problems in Japanese day workers using the 3-dimensional sleep scale (3DSS), which measures three sleep elements (phase, quality, and quantity). Data from 635 Japanese day workers (461 mens and 174 womens) were included. The 3DSS was used to assess participants? sleep condition. Participa...

  10. Day workers suffering from a wider range of sleep problems are more likely to experience suicidality.

    Science.gov (United States)

    Matsumoto, Yuuki; Uchimura, Naohisa; Ishida, Tetsuya; Toyomasu, Kouji; Morimatsu, Yoshitaka; Mori, Mihoko; Kushino, Nanae; Hoshiko, Michiko; Ishitake, Tatsuya

    2016-01-01

    Both a higher suicide rate and widespread sleep problems are serious health concerns in Japan when compared with those of other countries. We investigated the relationship between suicidal ideation and sleep problems in Japanese day workers using the 3-dimensional sleep scale (3DSS), which measures three sleep elements (phase, quality, and quantity). Data from 635 Japanese day workers (461 mens and 174 womens) were included. The 3DSS was used to assess participants' sleep condition. Participants were classified into eight sleep types based on scores of phase, quality, and quantity: All Good Sleep, Owl (poor phase), Inefficient (poor quality), Short (poor quantity), Owl + Inefficient (poor phase and quality), Owl + Short (poor phase and quantity), Inefficient + Short (poor quality and quantity), and All Poor Sleep. We assessed participants' suicidal ideation using question 19 of the self-rating depression scale (SDS); 119 cases (18.7 %) had ratings of 2-4 for this question and were considered to have suicidal ideation. The higher the number of sleep problems, the higher the risk of suicidal ideation compared to sleep types not indicative of problems. All Poor Sleep had the highest risk of the eight sleep types. Individuals with Owl + Short, Inefficient + Short, or All Poor Sleep had a significant risk of suicidal ideation even after adjusting for hopelessness and nightmares. Our findings suggested that sleep problems assessed by the 3DSS were related to suicidal ideation. Analysis of various aspects of sleep could be helpful for suicide prevention.

  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. SEMICONDUCTOR INTEGRATED CIRCUITS: DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range

    Science.gov (United States)

    Changming, Pi; Wei, Yan; Ke, Zhang; Wenhong, Li

    2010-08-01

    This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 μm CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency.

  14. DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range

    Energy Technology Data Exchange (ETDEWEB)

    Pi Changming; Yan Wei; Zhang Ke; Li Wenhong, E-mail: wenhongli@fudan.edu.c [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)

    2010-08-15

    This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 {mu}m CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency. (semiconductor integrated circuits)

  15. 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.

  16. The influence of step frequency on the range of perceptually natural visual walking speeds during walking-in-place and treadmill locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Christian; Serafin, Stefania; Nordahl, Rolf

    2014-01-01

    and virtual walking speeds. This paper details a study investigating the effects of movement type (treadmill walking and WIP) and step frequency (1.4, 1.8 and 2.2 steps per second) on the range of perceptually natural visual walking speeds. The results suggests statistically significant main effects of both...... movement type and step frequency but no significant interaction between the two variables....

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

    CERN Document Server

    Rebolini, Elisa

    2015-01-01

    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 four small molecules: N2, CO2, H2CO, and C2H4. The results suggest that the addition of the long-range second-order Bethe-Salpeter correlation kernel overall slightly improves the excitation energies.

  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. Review of a Method for Local Damping Identification in the Low- and Mid-Frequency Range Based on a Finite Element Model

    OpenAIRE

    Tang, Martin

    2017-01-01

    Passenger demand for enhanced cabin comfort have made cabin noise to an important factor. The damping behaviour of the cabin must be understood in order to predict noise emission. Due to the high modal density and overlap, state-of-the-art methods are not able to accurately identify damping in the mid- and high-frequency range. However, these frequency ranges are relevant in the field of acoustics. 2016 a method was proposed for local damping identification, which was applied to an aircra...

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

    Energy Technology Data Exchange (ETDEWEB)

    Pavelyev, D. G., E-mail: pavelev@rf.unn.ru, E-mail: obolensk@rf.unn.ru [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Vasilev, A. P., E-mail: vasiljev@mail.ioffe.ru [Russian Academy of Sciences, Submicron Heterostructures for Microelectronics, Research and Engineering Center (Russian Federation); Kozlov, V. A., E-mail: kozlov@ipm.sci-nnov.ru; Koschurinov, Yu. I.; Obolenskaya, E. S.; Obolensky, S. V. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Ustinov, V. M., E-mail: vmust@beam.ioffe.ru [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-11-15

    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.

  1. Interaction of electromagnetic radiation in the 20-200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles.

    Science.gov (United States)

    Atdayev, Agylych; Danilyuk, Alexander L; Prischepa, Serghej L

    2015-01-01

    The interaction of electromagnetic radiation with a magnetic nanocomposite based on carbon nanotubes (CNT) is considered within the model of distributed random nanoparticles with a core-shell morphology. The approach is based on a system composed of a CNT conducting resistive matrix, ferromagnetic inductive nanoparticles and the capacitive interface between the CNT matrix and the nanoparticles, which form resonance resistive-inductive-capacitive circuits. It is shown that the influence of the resonant circuits leads to the emergence of specific resonances, namely peaks and valleys in the frequency dependence of the permeability of the nanocomposite, and in the frequency dependence of the reflection and transmission of electromagnetic radiation.

  2. Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Agylych Atdayev

    2015-04-01

    Full Text Available The interaction of electromagnetic radiation with a magnetic nanocomposite based on carbon nanotubes (CNT is considered within the model of distributed random nanoparticles with a core–shell morphology. The approach is based on a system composed of a CNT conducting resistive matrix, ferromagnetic inductive nanoparticles and the capacitive interface between the CNT matrix and the nanoparticles, which form resonance resistive–inductive–capacitive circuits. It is shown that the influence of the resonant circuits leads to the emergence of specific resonances, namely peaks and valleys in the frequency dependence of the permeability of the nanocomposite, and in the frequency dependence of the reflection and transmission of electromagnetic radiation.

  3. Alternative low frequency magnetic field theranostics: recent advances, safety and hazards

    Science.gov (United States)

    Golovin, Y.; Klyachko, N.; Majouga, A.; Golovin, D.; Gribanovsky, S.

    2015-11-01

    The paper presents a brief review and comparative analysis of low frequency (nonheating) and radio-frequency electromagnetic nanomedicine technologies. The former are shown to have a considerable advantage over the latter ones: a higher flexibility and penetrating ability, easier to dose and control, easier to localize, as well as safer and less costly. This makes their employment promising for building a new technological platform for low frequency magnetic theranostics with a wider range of options, i.e. possessing a wider multimodality than traditional radio-frequency methods.

  4. High-resolution observation of field-aligned irregularities in the ionosphere using multi-frequency range imaging of VHF atmospheric radar

    Science.gov (United States)

    Chen, Jenn-Shyong; Furumoto, Jun-ichi; Su, Ching-Lun; Chu, Yen-Hsyang

    Field-aligned irregularity (FAI) in the ionosphere is a topic of interest to atmospheric radar community. In addition to the field-aligned characteristic, quasi-periodic (QP) appearance of FAI echoes has been observed frequently by very-high-frequency (VHF) atmospheric radar. The occurrence range of QP FAI echoes changes with time, and the slope of range versus time can be positive or negative, depending on occurrence time of the echoes. Several mechanisms responsible for the QP FAI echoes have been proposed, e.g., modulation in altitude by a passing atmospheric gravity wave, semidiurnal neutral-wind variation, and so on. Owing to the finite pulse length of radar in observation, the range resolution of measurement is limited within hundreds of meters. In view of this, the range imaging (RIM) using multiple frequencies has been employed to improve the range resolution of measurement. The multi-frequency technique transmits a set of slightly different frequencies sequentially during each radar pulse, and the radar returns at different transmitting frequencies are received, respectively. With adaptive retrieval algorithms for these radar returns, it is capable of resolving the echo structures at meter scale in the range direction. RIM has been employed in the lower atmosphere successfully. In this study, the performance of RIM for FAI was first carried out with the Middle and Upper atmosphere Radar (46 MHz; 34.85(°) N, 136.10(°) N; Japan) and the Chung-Li VHF radar (52 MHz; 24.9(°) N, 121.1(°) E; Taiwan). Some initial results of high-resolution FAI echoes within the range gate will be shown.

  5. Effect of continuous irradiation with terahertz electromagnetic waves of the NO frequency range on behavioral reactions of male albino rats under stress conditions.

    Science.gov (United States)

    Kirichuk, V F; Antipova, O N; Krylova, Ya A

    2014-06-01

    We studied the effect of terahertz waves (NO frequency range, 150.176-150.664 GHz) on stress-induced variations in behavioral reactions of male albino rats during hypokinetic stress. THz irradiation was followed by partial or complete normalization of behavioral reactions of male albino rats after hypokinetic stress. The most significant effect was observed after continuous irradiation for 30 min.

  6. Primary Calibration of Hydrophones in the Frequency Range of 250 Hz to 500 kHz Using Three-Transducer Spherical Wave Reciprocity

    Science.gov (United States)

    2016-08-01

    LIST OF MATHEMATICAL SYMBOLS AND UNITS ................................................. iii 1 INTRODUCTION ...HYDROPHONES IN THE FREQUENCY RANGE 250 HZ TO 500 KHZ USING THREE-TRANSDUCER SPHERICAL WAVE RECIPROCITY 1. INTRODUCTION This document describes the...for algae , there is little aquatic vegetation. Calibration measurements were performed on 22 June 2016. Environmental conditions during the

  7. A High-Voltage class-D power amplifier with switching frequency regulation for improved high-efficiency output power range

    NARCIS (Netherlands)

    Ma, H.; van der Zee, Ronan A.R.; Nauta, Bram

    2015-01-01

    This paper describes the power dissipation analysis and the design of an efficiency-improved high-voltage class-D power amplifier. The amplifier adaptively regulates its switching frequency for optimal power efficiency across the full output power range. This is based on detecting the switching

  8. Microstrip Antennas with Polarization Diversity across a Wide Frequency Range and Phased Array Antennas for Radar and Satellite Communications

    OpenAIRE

    Ho, Kevin Ming-Jiang

    2014-01-01

    The thesis comprises of 3 projects; an L-band microstrip antenna with frequency agility and polarization diversity, X-band phased array antennas incorporating commercially packaged RFIC phased array chips, and studies for Ku/Ka- band shared aperture antenna array. The first project features the use of commercially packaged RF-MEMS SPDT switches, that boasts of high reliability, high linearity, low losses, hermetically packaged and fully compatible for SMTA processes for mass-assembly and prod...

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

    Energy Technology Data Exchange (ETDEWEB)

    Fannin, P.C. [Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2 (Ireland); Vekas, L. [Center for Fundamental Technical Research, Romanian Academy-Timisoara Branch, Timisoara (Romania); Marin, C.N., E-mail: catalin.marin@e-uvt.ro [West University of Timisoara, Faculty of Physics, V. Parvan Blv., no. 4, 300223 Timisoara (Romania); Malaescu, I. [West University of Timisoara, Faculty of Physics, V. Parvan Blv., no. 4, 300223 Timisoara (Romania)

    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. - 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.

  10. Influence of temporal noise on the skin blood flow measurements performed by cooled thermal imaging camera: limit possibilities within each physiological frequency range

    Science.gov (United States)

    Sagaidachnyi, A. A.; Volkov, I. U.; Fomin, A. V.

    2016-04-01

    This paper describes limit possibilities of modern cooled thermal imaging cameras as a tool for estimation of blood flow oscillations at the surface of living body. Skin temperature oscillations, as we assumed, are a consequence of the blood flow oscillations. We considered the temperature sensitivity 0.01-0.02 °C as a typical for the most of modern cooled long wave thermal imaging cameras. Fourier filter used to investigate the temperature signal separately within endothelial, neurogenic, myogenic, respiratory and cardiac frequency ranges. The level of temporal noise has been estimated during measurements of no living body with stabilized temperature ~ 24°C. The level of temperature oscillations has been calculated for the group of healthy subjects within each frequency range. Thus, we were able to determine signal-to-noise ratio within frequency band [0.001, 1] Hz. As a result, we determine that skin temperature oscillations measured by thermal imaging camera with sensitivity 0.02°C have the upper frequency limit ~ 0.2 Hz. In other words, within the respiratory and cardiac frequency ranges of blood flow oscillations the noise level exceeds signal one, and temperature measurements at the skin surface are practically useless. The endothelial, neurogenic and myogenic components of the temperature oscillations contain ~98% of the total spectral power of the signal. We have plot the empirical extrapolated curve of sensitivity of thermal imaging camera vs. frequency of the temperature oscillations. The data analysis shows that measurements of skin temperature oscillations within respiratory and cardiac ranges require the temperature sensitivity at least ~ 0.01°C and 0.001°C, respectively.

  11. On the Frequency and Voltage-Dependent Profiles of the Surface States and Series Resistance of Au/ZnO/n-Si Structures in a Wide Range of Frequency and Voltage

    Science.gov (United States)

    Nikravan, Afsoun; Badali, Yosef; Altındal, Şemsettin; Uslu, İbrahim; Orak, İkram

    2017-10-01

    In order to interpret the electrical characteristics of fabricated Au/ZnO/n-Si structures as a function of frequency and voltage well, their capacitance-voltage ( C- V) and conductance-voltage ( G/ ω- V) measurements were carried out in a wide range of frequencies (0.7 kHz-2 MHz) and voltages (± 6 V) by 50 mV steps at room temperature. Both the C- V and G/ ω- V plots have reverse, depletion, and accumulation regions such as a metal-insulator/oxide semiconductor (MIS or MOS) structures. The values of doped-donor atoms ( N D), Fermi energy level ( E F), barrier height (ΦB), and series resistance ( R s) of the structure were obtained as a function of frequency and voltage. While the value of N D decreases with increasing frequency almost as exponentially, the value of depletion width ( W D) increases. The values of C and G/ ω increase with decreasing frequency because the surface states ( N ss) are able to follow the alternating current (AC) signal, resulting in excess capacitance ( C ex) and conductance ( G ex/ ω), which depends on their relaxation time and the frequency of the AC signal. The voltage-dependent profiles of N ss were obtained from both the high-low frequency capacitance and Hill-Colleman methods. The other important parameter R s of the structure was also obtained from the Nicollian and Brews methods as a function of voltage.

  12. Note: Ultra-high frequency ultra-low dc power consumption HEMT amplifier for quantum measurements in millikelvin temperature range.

    Science.gov (United States)

    Korolev, A M; Shnyrkov, V I; Shulga, V M

    2011-01-01

    We have presented theory and experimentally demonstrated an efficient method for drastically reducing the power consumption of the rf/microwave amplifiers based on HEMT in unsaturated dc regime. Conceptual one-stage 10 dB-gain amplifier showed submicrowatt level of the power consumption (0.95 μW at frequency of 0.5 GHz) when cooled down to 300 mK. Proposed technique has a great potential to design the readout amplifiers for ultra-deep-cooled cryoelectronic quantum devices.

  13. 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.

  14. Antimicrobial resistance in humans, livestock and the wider environment.

    Science.gov (United States)

    Woolhouse, Mark; Ward, Melissa; van Bunnik, Bram; Farrar, Jeremy

    2015-06-05

    Antimicrobial resistance (AMR) in humans is inter-linked with AMR in other populations, especially farm animals, and in the wider environment. The relatively few bacterial species that cause disease in humans, and are the targets of antibiotic treatment, constitute a tiny subset of the overall diversity of bacteria that includes the gut microbiota and vast numbers in the soil. However, resistance can pass between these different populations; and homologous resistance genes have been found in pathogens, normal flora and soil bacteria. Farm animals are an important component of this complex system: they are exposed to enormous quantities of antibiotics (despite attempts at reduction) and act as another reservoir of resistance genes. Whole genome sequencing is revealing and beginning to quantify the two-way traffic of AMR bacteria between the farm and the clinic. Surveillance of bacterial disease, drug usage and resistance in livestock is still relatively poor, though improving, but achieving better antimicrobial stewardship on the farm is challenging: antibiotics are an integral part of industrial agriculture and there are very few alternatives. Human production and use of antibiotics either on the farm or in the clinic is but a recent addition to the natural and ancient process of antibiotic production and resistance evolution that occurs on a global scale in the soil. Viewed in this way, AMR is somewhat analogous to climate change, and that suggests that an intergovernmental panel, akin to the Intergovernmental Panel on Climate Change, could be an appropriate vehicle to actively address the problem.

  15. Saharan Rock Art: Local Dynamics and Wider Perspectives

    Directory of Open Access Journals (Sweden)

    Marina Gallinaro

    2013-12-01

    Full Text Available Rock art is the best known evidence of the Saharan fragile heritage. Thousands of engraved and painted artworks dot boulders and cliffs in open-air sites, as well as the rock walls of rockshelters and caves located in the main massifs. Since its pioneering discovery in the late 19th century, rock art captured the imagination of travellers and scholars, representing for a long time the main aim of research in the area. Chronology, meaning and connections between the different recognized artistic provinces are still to be fully understood. The central massifs, and in particular the "cultural province" encompassing Tadrart Acacus and Tassili n’Ajer, played and still play a key role in this scenario. Recent analytical and contextual analyses of rock art contexts seem to open new perspectives. Tadrart Acacus, for the richness and variability of artworks, for the huge archaeological data known, and for its proximity to other important areas with rock art (Tassili n’Ajjer, Algerian Tadrart and Messak massifs is an ideal context to analyze the artworks in their environmental and social-cultural context, and to define connections between cultural local dynamics and wider regional perspectives.

  16. Local complex permittivity measurements of porcine skin tissue in the frequency range from 1 GHz to 15 GHz by evanescent microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kleismit, Richard A; Kozlowski, Gregory; Foy, Brent D [Department of Physics, Wright State University, 3640 Col. Glenn Hwy, Dayton, OH 45435-0001 (United States); Hull, Barbara E [Department of Biological Sciences, Wright State University, 3640 Col. Glenn Hwy, Dayton, OH 45435-0001 (United States); Kazimierczuk, Marian [Department of Electrical Engineering, Wright State University, 3640 Col. Glenn Hwy, Dayton, OH 45435-0001 (United States)], E-mail: richard.kleismit@wright.edu

    2009-02-07

    The near-field evanescent microwave microscope is based on a coaxial transmission line resonator with a silver plated tungsten tip protruding through an end-wall aperture. The sensor is used to measure the local dielectric properties of porcine skin in the frequency range from 1 GHz to 15 GHz. The dielectric property of the skin within the near field of the tip frustrates the electric field and measurably changes the transmission line's resonant frequency and quality factor (Q). The shift of the resonator's frequency and Q is measured as a function of tip-sample separation, and a quantitative relationship between the real and imaginary parts of the local dielectric constant using the method of images is established. The associated changes in quality factor image scans of subsurface tissue structure and dielectric properties of skin surface lesions are presented.

  17. DNA Repair Domain Modeling Can Predict Cell Death and Mutation Frequency for Wide Range Spectrum of Radiation

    Science.gov (United States)

    Viger, Louise; Ponomarev, Artem L.; Plante, Ianik; Evain, Trevor; Penninckx, Sebastien; Blattnig, Steve R.; Costes, Sylvain V.

    2017-01-01

    Exploration missions to Mars and other destinations raise many questions about the health of astronauts. The continuous exposure of astronauts to galactic cosmic rays is one of the main concerns for long-term missions. Cosmic ionizing radiations are composed of different ions of various charges and energies notably, highly charged energy (HZE) particles. The HZE particles have been shown to be more carcinogenic than low-LET radiation, suggesting the severity of chromosomal aberrations induced by HZE particles is one possible explanation. However, most mathematical models predicting cell death and mutation frequency are based on directly fitting various HZE dose response and are in essence empirical approaches. In this work, we assume a simple biological mechanism to model DNA repair and use it to simultaneously explain the low- and high-LET response using the exact same fitting parameters. Our work shows that the geometrical position of DNA repair along tracks of heavy ions are sufficient to explain why high-LET particles can induce more death and mutations. Our model is based on assuming DNA double strand breaks (DSBs) are repaired within repair domain, and that any DSBs located within the same repair domain cluster into one repair unit, facilitating chromosomal rearrangements and increasing the probability of cell death. We introduced this model in 2014 using simplified microdosimetry profiles to predict cell death. In this work, we collaborated with NASA Johnson Space Center to generate more accurate microdosimetry profiles derived by Monte Carlo techniques, taking into account track structure of HZE particles and simulating DSBs in realistic cell geometry. We simulated 224 data points (D, A, Z, E) with the BDSTRACKS model, leading to a large coverage of LET from 10 to 2,400 keV/µm. This model was used to generate theoretical RBE for various particles and energies for both cell death and mutation frequencies. The RBE LET dependence is in agreement with

  18. Effect of model-form definition on uncertainty quantification in coupled models of mid-frequency range simulations

    Science.gov (United States)

    Van Buren, Kendra L.; Ouisse, Morvan; Cogan, Scott; Sadoulet-Reboul, Emeline; Maxit, Laurent

    2017-09-01

    In the development of numerical models, uncertainty quantification (UQ) can inform appropriate allocation of computational resources, often resulting in efficient analysis for activities such as model calibration and robust design. UQ can be especially beneficial for numerical models with significant computational expense, such as coupled models, which require several subsystem models to attain the performance of a more complex, inter-connected system. In the coupled model paradigm, UQ can be applied at either the subsystem model level or the coupled model level. When applied at the subsystem level, UQ is applied directly to the physical input parameters, which can be computationally expensive. In contrast, UQ at the coupled level may not be representative of the physical input parameters, but comes at the benefit of being computationally efficient to implement. To be physically meaningful, analysis at the coupled level requires information about how uncertainty is propagated through from the subsystem level. Herein, the proposed strategy is based on simulations performed at the subsystem level to inform a covariance matrix for UQ performed at the coupled level. The approach is applied to a four-subsystem model of mid-frequency vibrations simulated using the Statistical Modal Energy Distribution Analysis, a variant of the Statistical Energy Analysis. The proposed approach is computationally efficient to implement, while simultaneously capturing information from the subsystem level to ensure the analysis is physically meaningful.

  19. Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range.

    Science.gov (United States)

    Chen, Hetuo; Fu, Xuewen; An, Qi; Tang, Bin; Zhang, Shuren; Yang, Hao; Long, Yin; Harfouche, Mark; Wang, Huolei; Li, Yingxiang

    2017-10-26

    Microwave dielectric ceramic materials are extensively utilized in microwave applications because of their high dielectric constants and quality factors. These applications also require ceramics of zero temperature coefficients at the resonant frequency (τ f ), which can be realized through mixing a ceramic that one is interested in with another ceramic with -τ f , or by performing the ionic substitution. With the mixing/ionic substitution, it is indispensable to compute the quality factors precisely. Previous study indicates that the quality factor depends on the grain size, porosity, internal strain, structure, phase evolution, and conductivity etc. Here we derive a quality factor formula based on the definition, which works very well for multiphase composites, single phase solid solutions, and equivalent ionic substituted single phase materials. Our formula calculation and fits to the previous experimental results demonstrate that the quality factor of the ceramic mixtures strongly depend on the dielectric constants and the dielectric constant variation index. Our results suggest that the impacts from grain size, porosity, and internal strain etc. can be summarized to the dielectric constant or dielectric constant variation index, which is of great importance for future design of high performance microwave dielectric ceramics.

  20. Linear-array-based photoacoustic imaging of human microcirculation with a range of high frequency transducer probes.

    Science.gov (United States)

    Zafar, Haroon; Breathnach, Aedán; Subhash, Hrebesh M; Leahy, Martin J

    2015-05-01

    Photoacoustic imaging (PAI) with a linear-array-based probe can provide a convenient means of imaging the human microcirculation within its native structural context and adds functional information. PAI using a multielement linear transducer array combined with multichannel collecting system was used for in vivo volumetric imaging of the blood microcirculation, the total concentration of hemoglobin (HbT), and the hemoglobin oxygen saturation (sO₂) within human tissue. Three-dimensional (3-D) PA and ultrasound (US) volumetric scans were acquired from the forearm skin by linearly translating the transducer with a stepper motor over a region of interest, while capturing two-dimensional images using 15, 21, and 40 MHz frequency transducer probes. For the microvasculature imaging, PA images were acquired at 800- and 1064-nm wavelengths. For the HbT and sO₂ estimates, PA images were collected at 750- and 850-nm wavelengths. 3-D microcirculation, HbT, and sO₂ maps of the forearm skin were obtained from normal subjects. The linear-array-based PAI has been found promising in terms of resolution, imaging depth, and imaging speed for in vivo microcirculation imaging within human skin. We believe that a reflection type probe, similar to existing clinical US probes, is most likely to succeed in real clinical applications. Its advantages include ease of use, speed, and familiarity for radiographers and clinicians.

  1. Characterization of Different Cable Ferrite Materials to Reduce the Electromagnetic Noise in the 2-150 kHz Frequency Range.

    Science.gov (United States)

    Suarez, Adrian; Victoria, Jorge; Alcarria, Antonio; Torres, Jose; Martinez, Pedro A; Martos, Julio; Soret, Jesus; Garcia-Olcina, Raimundo; Muetsch, Steffen

    2018-01-23

    The gap of standardization for conducted and field coupled electromagnetic interferences (EMI) in the 2-150 kHz frequency range can lead to Electromagnetic Compatibility (EMC) problems. This is caused by power systems such as Pulse Width Modulation (PWM) controlled rectifiers, photovoltaic inverters or charging battery units in electric vehicles. This is a very important frequency spectral due to interferences generated in a wide range of devices and, specifically, communication problems in the new technologies and devices incorporated to the traditional grid to convert it into a Smart Grid. Consequently, it is necessary to provide new solutions to attenuate this kind of interference, which involves finding new materials that are able to filter the electromagnetic noise. This contribution is focused on characterizing the performance of a novel material based on nanocrystalline and comparing it to most common material compositions such as MnZn and NiZn. This research is carried out from the point of view of the manufacturing process, magnetic properties and EMI suppression ability. This last item is carried out through two analysis procedures: a theoretical method by determining the attenuation ratio by measuring impedance parameter and proposing a new empirical technique based on measuring directly the insertion loss parameter. Therefore, the main aim of this characterization process is to determine the performance of nanocrystalline compared to traditional cable ferrite compositions to reduce the interferences in this controversial frequency range. From the results obtained, it is possible to deduce that nanocrystalline cable ferrite provides the best performance to filter the electromagnetic noise in the 2-150 kHz frequency range.

  2. 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).

  3. On the dispersion management of fluorite whispering-gallery mode resonators for Kerr optical frequency comb generation in the telecom and mid-infrared range.

    Science.gov (United States)

    Lin, Guoping; Chembo, Yanne K

    2015-01-26

    Optical whispering gallery mode (WGM) resonators have been very attracting platforms for versatile Kerr frequency comb generations. We report a systematic study on the material dispersion of various optical materials that are capable of supporting quality factors above 109. Using an analytical approximation of WGM resonant frequencies in disk resonators, we investigate the effect of the geometry and transverse mode order on the total group-velocity dispersion (GVD). We demonstrate that the major radii and the radial mode indices play an important role in tailoring the GVD of WGM resonators. In particular, our study shows that in WGM disk-resonators, the polar families of modes have very similar GVD, while the radial families of modes feature dispersion values that can differ by up to several orders of magnitude. The effect of these giant dispersion shifts are experimentally evidenced in Kerr comb generation with magnesium fluoride. From a more general perspective, this critical feature enables to push the zero-dispersion wavelength of fluorite crystals towards the mid-infrared (mid-IR) range, thereby allowing for efficient Kerr comb generation in that spectral range. We show that barium fluoride is the most interesting crystal in this regard, due to its zero dispersion wavelength (ZDW) at 1.93 μm and an optimal dispersion profile in the mid-IR regime. We expect our results to facilitate the design of different platforms for Kerr frequency comb generations in both telecommunication and mid-IR spectral ranges.

  4. Discharge physics and influence of the modulation on helium DBD modes in the medium-frequency range at atmospheric pressure

    Science.gov (United States)

    Boisvert, Jean-Sébastien; Margot, Joëlle; Massines, Françoise

    2017-04-01

    In this paper the recently reported hybrid mode (a dielectric barrier discharge (DBD) excited by an electric field oscillating at about 1 MHz) is investigated using space and time-resolved imaging together with electrical measurements. In contrast with the helium low-frequency DBD, at 1.6 MHz the light emission is desynchronized with the discharge current. It rather depends on the enhanced rate of stepwise excitation resulting from the massive secondary emission occurring 0.15Ƭ after the discharge current maximum (Ƭ is the excitation wave period). The consequence of ion impacts on the dielectric surfaces is a higher gas and dielectric temperatures as compared to typical helium DBDs. The electrical behavior and the gas temperature of a pulsed dielectric-barrier discharge operated at 1.6 MHz are also described in this paper as a function of the repetition rate (varying from 1 Hz to 10 kHz). The gas temperature is reduced when repetition rates higher or equal to 10 Hz is used. This is related to the gas renewal rate of 8.3 Hz, i.e., gas residence time of 120 ms in our conditions. In addition, due to the memory effect in the gas, the gas gap voltage decreases as the repetition rate increases. However, beyond 100 Hz, the power decreases and the gas gap voltage increases again. As a consequence, for a given power density, the optimal repetition rate is 100 Hz which minimizes the gas temperature without reducing the power density. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  5. 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.

  6. Engaging wider publics with studying and protecting the ocean

    Science.gov (United States)

    Nauen, Cornelia E.

    2015-04-01

    The ocean is dying. The vast scientific literature diagnoses massive reductions in the biomass of fish and invertebrates from overfishing, increasing destruction of coral ecosystems in the tropics from climate change, extensive dead zones from eutrophication and collapse of marine bird populations from ingesting plastic. Even though Darwin suspected already The scale is becoming apparent only from meta-analyses at regional or even global scales as individual studies tend to focus on one fishery or one type of organisms or geographic location. In combination with deep rooted perceptions of the vastness of the ocean the changes are difficult to comprehend for specialists and the general public alike. Even though more than half of humanity is estimated to live in coastal zones as defined by some, urbanisation is removing about half from regular, more direct exposure. Yet, there is much still to be explored, not only in the deep, little studied, parts. The ocean exercises great fascination on many people heightened since the period of discovery and the mystery of far-flung places, but the days, when Darwin's research results were regularly discussed in public spaces are gone. Rachel Carson's prize-winning and best selling book "The Sea Around Us", some serialised chapters in magazines and condensations in "Reader's Digest" transported the poetic rendering of science again to a wider public. But compared to the diversity of scientific inquiry about the ocean and importance for life-support system earth there is much room for engaging ocean science in the broad sense with larger and diverse publics. Developing new narratives rooted in the best available sciences is among the most promising modes of connecting different areas of scientific inquiry and non-specialists alike. We know at latest since Poincaré's famous dictum that "the facts don't speak". However, contextualised information can capture the imagination of the many and thus also reveal unexpected connections

  7. Time constants for temperature elevation in human models exposed to dipole antennas and beams in the frequency range from 1 to 30 GHz

    Science.gov (United States)

    Morimoto, Ryota; Hirata, Akimasa; Laakso, Ilkka; Ziskin, Marvin C.; Foster, Kenneth R.

    2017-03-01

    This study computes the time constants of the temperature elevations in human head and body models exposed to simulated radiation from dipole antennas, electromagnetic beams, and plane waves. The frequency range considered is from 1 to 30 GHz. The specific absorption rate distributions in the human models are first computed using the finite-difference time-domain method for the electromagnetics. The temperature elevation is then calculated by solving the bioheat transfer equation. The computational results show that the thermal time constants (defined as the time required to reach 63% of the steady state temperature elevation) decrease with the elevation in radiation frequency. For frequencies higher than 4 GHz, the computed thermal time constants are smaller than the averaging time prescribed in the ICNIRP guidelines, but larger than the averaging time in the IEEE standard. Significant differences between the different head models are observed at frequencies higher than 10 GHz, which is attributable to the heat diffusion from the power absorbed in the pinna. The time constants for beam exposures become large with the increase in beam diameter. The thermal time constant in the brain is larger than that in the superficial tissues at high frequencies, because the brain temperature elevation is caused by the heat conduction of energy absorbed in the superficial tissue. The thermal time constant is minimized with an ideal beam with a minimum investigated diameter of 10 mm this minimal time constant is approximately 30 s and is almost independent of the radiation frequency, which is supported by analytic methods. In addition, the relation between the time constant, as defined in this paper, and ‘averaging time’ as it appears in the exposure limits is discussed, especially for short intense pulses. Similar to the laser guidelines, provisions should be included in the limits to limit the fluence for such pulses.

  8. 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

  9. 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

  10. Micromachining and validation of the scanning acoustic microscope spatial resolution and sensitivity calibration block for 20-230 MHz frequency range.

    Science.gov (United States)

    Tamulevičius, Tomas; Šimatonis, Linas; Ulčinas, Orestas; Tamulevičius, Sigitas; Žukauskas, Egidijus; Rekuvienė, Regina; Mažeika, Liudas

    2016-10-01

    Scanning acoustic microscopy (SAM) is used as a routine non-destructive test tool for different diagnostic examinations: detection of defects such as microcracks, delamination, disbonding, inclusions, subsurface features in materials such as pores and cracks. SAM can be operated in a wide frequency range from Megahertz to Gigahertz. SAM measurement spatial resolution is diffraction limited by the wavelength of the acoustic wave in particular medium and also depends on individual transducers geometry. Actual SAM spatial resolution can be determined by measuring calibrated lithographically formed microstructures in high acoustic impedance materials. Numerical acoustic signal simulation method, based on the diffraction approach, was employed for the selection of the calibration block pattern geometry and linear dimensions of the elements. Universal calibration block for SAM operating in a 20-230 MHz frequency range was micromachined in high acoustic impedance ceramic substrates. Differently spaced (from 18 to 185 µm) lines of the same width and different widths (from 17 to 113 µm) but similar spacing lines were imposed in alumina ceramics employing one step lithography process, i.e. femtosecond laser ablation. Proposed SAM calibration pattern linear dimensions were characterized employing optical and scanning electron microscopy. Finally the samples were measured with SAM employing different frequency transducers and results were compared with the numerical simulations. It was obtained that resolution of SAM operating with 230 MHz transducer is not worse than 40 µm. © The Author (2016). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

  11. Image-Guided Ultrasound Characterization of Volatile Sub-Micron Phase-Shift Droplets in the 20-40 MHz Frequency Range.

    Science.gov (United States)

    Sheeran, Paul S; Daghighi, Yasaman; Yoo, Kimoon; Williams, Ross; Cherin, Emmanuel; Foster, F Stuart; Burns, Peter N

    2016-03-01

    Phase-shift perfluorocarbon droplets are designed to convert from the liquid to the gas state by the external application of acoustic or optical energy. Although droplet vaporization has been investigated extensively at ultrasonic frequencies between 1 and 10 MHz, few studies have characterized performance at the higher frequencies commonly used in small animal imaging. In this study, we use standard B-mode imaging sequences on a pre-clinical ultrasound platform to both image and activate sub-micron decafluorobutane droplet populations in vitro and in vivo at center frequencies in the range of 20-40 MHz. Results show that droplets remain stable against vaporization at low imaging pressures but are vaporized at peak negative pressures near 3.5 MPa at the three frequencies tested. This study also found that a small number of size outliers present in the distribution can greatly influence droplet performance. Removal of these outliers results in a more accurate assessment of the vaporization threshold and produces free-flowing microbubbles upon vaporization in the mouse kidney. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  12. Ion cyclotron range of frequencies mode conversion electron heating in deuterium-hydrogen plasmas in the Alcator C-Mod tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wukitch, S J [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bonoli, P T [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Marmar, E [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Mossessian, D [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Nelson-Melby, E [Centre de Recherches en Physique des Plasmas, Association EURATOM - Confederation Suisse, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Phillips, P [Fusion Research Center, University of Texas, Austin, Texas 78712 (United States); Porkolab, M [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Schilling, G [Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Wolfe, S [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wright, J [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2003-06-01

    Localized direct electron heating (EH) by mode-converted (MC) ion cyclotron range of frequencies (ICRF) waves in D(H) tokamak plasmas has been clearly observed for the first time in Alcator C-Mod. Both on- and off-axis (high field side) mode conversion EH (MCEH) have been observed. The MCEH profile was obtained from a break-in-slope analysis of electron temperature signals in the presence of radio frequency shut-off. The temperature was measured by a 32-channel high spatial resolution ({<=}7 mm) 2nd harmonic heterodyne electron cyclotron emission system. The experimental profiles were compared with the predictions from a toroidal full-wave ICRF code TORIC. Using the hydrogen concentration measured by a high-resolution optical spectrometer, TORIC predictions were shown qualitatively in agreement with the experimental results for both on- and off-axis MC cases. From the simulations, the EH from MC ion cyclotron wave and ion Bernstein wave is examined.

  13. The acoustic power of a vibrating clamped circular plate revisited in the wide low frequency range using expansion into the radial polynomials.

    Science.gov (United States)

    Rdzanek, Wojciech P

    2016-06-01

    This study deals with the classical problem of sound radiation of an excited clamped circular plate embedded into a flat rigid baffle. The system of the two coupled differential equations is solved, one for the excited and damped vibrations of the plate and the other one-the Helmholtz equation. An approach using the expansion into radial polynomials leads to results for the modal impedance coefficients useful for a comprehensive numerical analysis of sound radiation. The results obtained are accurate and efficient in a wide low frequency range and can easily be adopted for a simply supported circular plate. The fluid loading is included providing accurate results in resonance.

  14. 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.

  15. 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.

  16. Dielectric spectroscopy of SiO2, ZnO - nanoparticle loaded epoxy resin in the frequency range of 20 Hz to 2 MHz

    Science.gov (United States)

    Thakor, Sanketsinh; Rana, V. A.; Vankar, H. P.

    2017-05-01

    In present work, Bisphenol A-(epichlorhydrin); epoxy resin with hardener N(3-dimethylaminopropyl)-1,3-propylenediamine were used to determine the dielectric properties. Sample of the neat epoxy resin and nanoparticle loaded epoxy resin in the form of disc were prepared of different weight fraction. SiO2 and ZnO nanoparticles were taken as filler in the epoxy resin. Complex permittivity of the prepared samples was measured in the frequency range of 20 Hz to 2 MHz using precision LCR meter at room temperature. The charismatic change in dielectric behavior based on type and concentration of nanoparticle are discussed in detail.

  17. 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.

  18. Oven controlled N++ [1 0 0] length-extensional mode silicon resonator with frequency stability of 1 ppm over industrial temperature range

    Science.gov (United States)

    You, Weilong; Pei, Binbin; Sun, Ke; Zhang, Lei; Yang, Heng; Li, Xinxin

    2017-10-01

    This paper presents an oven controlled N++ [1 0 0] length-extensional mode silicon resonator, with a lookup-table based control algorithm. The temperature coefficient of resonant frequency (TCF) of the N++ doped resonator is nonlinear, and there is a turnover temperature point at which the TCF is equal to zero. The resonator is maintained at the turnover point by Joule heating; this temperature is a little higher than the upper limit of the industrial temperature range. It is demonstrated that the control algorithm based on the thermoresistor on the substrate and the lookup table for heating voltage versus chip temperature is sufficiently accurate to achieve a frequency stability of  ±0.5 ppm over the industrial temperature range. Because only two leads are required for electrical heating and piezoresistive sensing, the power required for heating of this resonator can be potentially lower than that of the oscillators with closed-loop oven control algorithm. It is also shown that the phase noise can be suppressed at the turnover temperature because of the very low value of the TCF, which justifies the usage of the heating voltage as the excitation voltage of the Wheatstone half-bridge.

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

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Gernot [Austrian Research Centers GmbH-ARC, ITM, A-2444 Seibersdorf (Austria); Ueberbacher, Richard [Austrian Research Centers GmbH-ARC, ITM, A-2444 Seibersdorf (Austria); Samaras, Theodoros [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Tschabitscher, Manfred [Center of Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna (Austria); Mazal, Peter R [Department of Clinical Pathology, Medical University Vienna, A-1090 Vienna (Austria)

    2007-09-07

    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 {mu}W, 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lysoivan, A.I. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Moiseenko, V.E. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Plyusnin, V.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Kasilov, S.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Bondarenko, V.N. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Chechkin, V.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Fomin, I.P. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Grigor`eva, L.I. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Konovalov, V.G. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Koval`ov, S.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Litvinov, A.P. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Mironov, Yu.K. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Nazarov, N.I. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Pavlichenko, O.S. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Pavlichenko, R.O. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Shapoval, A.N. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Skibenko, A.I. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center; Volkov, E.D. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Sci. Center

    1995-01-01

    Numerical and experimental results of Alfven wave heating of plasmas in the frequency range below the ion cyclotron frequency ({omega}<{omega}{sub 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{sup 13}cm{sup -3}). When using the THTA, the experiments performed showed the possibility of dense plasma production (more than 2x10{sup 13}cm{sup -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. Rotation of Magnetization Derived from Brownian Relaxation in Magnetic Fluids of Different Viscosity Evaluated by Dynamic Hysteresis Measurements over a Wide Frequency Range

    Directory of Open Access Journals (Sweden)

    Satoshi Ota

    2016-09-01

    Full Text Available The dependence of magnetic relaxation on particle parameters, such as the size and anisotropy, has been conventionally discussed. In addition, the influences of external conditions, such as the intensity and frequency of the applied field, the surrounding viscosity, and the temperature on the magnetic relaxation have been researched. According to one of the basic theories regarding magnetic relaxation, the faster type of relaxation dominates the process. However, in this study, we reveal that Brownian and Néel relaxations coexist and that Brownian relaxation can occur after Néel relaxation despite having a longer relaxation time. To understand the mechanisms of Brownian rotation, alternating current (AC hysteresis loops were measured in magnetic fluids of different viscosities. These loops conveyed the amplitude and phase delay of the magnetization. In addition, the intrinsic loss power (ILP was calculated using the area of the AC hysteresis loops. The ILP also showed the magnetization response regarding the magnetic relaxation over a wide frequency range. To develop biomedical applications of magnetic nanoparticles, such as hyperthermia and magnetic particle imaging, it is necessary to understand the mechanisms of magnetic relaxation.

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Jaeger, E. F. [XCEL Engineering, Inc., Oak Ridge, Tennessee 37830 (United States); Green, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Harvey, R. W. [CompX, Del Mar, California 92014 (United States)

    2012-08-15

    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-{sup 3}He plasmas. The measured mode converted wave intensity in the D-{sup 3}He mode conversion regime was found to be a factor of {approx}50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  3. Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod

    Science.gov (United States)

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

    2015-08-01

    Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-3He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.

  4. Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Tsujii, N., E-mail: tsujii@k.u-tokyo.ac.jp [Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561 (Japan); Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Jaeger, E. F. [XCEL Engineering, Inc., Oak Ridge, Tennessee 37830 (United States); Green, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Harvey, R. W. [CompX, Del Mar, California 92014 (United States)

    2015-08-15

    Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-{sup 3}He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.

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

    Science.gov (United States)

    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.

  6. 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

  7. Frequency-resolved optical gating system with a tellurium crystal for characterizing free-electron lasers in the wavelength range of 10-30 microm.

    Science.gov (United States)

    Iijima, Hokuto; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi; Minehara, Eisuke J

    2009-12-01

    A second-harmonic generation frequency-resolved optical gating (SHG-FROG) system has been developed for the complete characterization of laser pulses in the wavelength range of 10-30 microm. A tellurium crystal is used so that spectrally resolved autocorrelation signals with a good signal-to-noise ratio are obtained. Pulses (wavelength approximately 22 microm) generated from a free-electron laser are measured by the SHG-FROG system. The SHG intensity profile and the spectrum obtained by FROG measurements are well consistent with those of independent measurements of the pulse length and spectrum. The pulse duration and spectral width determined from the FROG trace are 0.6 ps and 5.2 THz at full width half maximum, respectively.

  8. Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception.

    Directory of Open Access Journals (Sweden)

    Carl Hopkins

    Full Text Available Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception.

  9. Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception.

    Science.gov (United States)

    Hopkins, Carl; Maté-Cid, Saúl; Fulford, Robert; Seiffert, Gary; Ginsborg, Jane

    2016-01-01

    Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception.

  10. Wider Reading at Key Stage 3: Happy Accidents, Bootlegging and Serial Readers

    Science.gov (United States)

    Westbrook, Jo

    2007-01-01

    This paper reports a small-scale study of wider reading at Key Stage 3 in current English classrooms in secondary schools in the south of England. Six English teachers, three of whom were relatively new to teaching, were interviewed on what they thought about wider reading. The findings indicate that because of a lack of time and absence of demand…

  11. ALIVE-IN-RANGE MEDIUM ACCESS CONTROL PROTOCOL TO MINIMIZE DELAY IN UNDERWATER WIRELESS SENSOR NETWORK COMMUNICATION AT A FREQUENCY OF 2.4 GHz

    Directory of Open Access Journals (Sweden)

    VIKAS RAINA

    2017-11-01

    Full Text Available Time synchronization between the sensor nodes to reduce end to end delay for critical and real time data monitoring can be achieved by cautiously monitoring the mobility of the mobile sink node in underwater wireless sensor networks. The proposed Alive-in-Range (AR-MAC medium access control protocol monitors delay sensitive, critical and real time data. The idea evolves as a reduction in duty cycle, precise time scheduling of active/sleep cycles of the sensors, monitoring the mobility of the sink node along-with the selection of appropriate queues and schedulers can reduce the end to end delay enhancing other performance metrics too. The algorithms effective path determination and optimum throughput path determination are proposed. It is assumed that the sensors are properly anchored to limit their movement due to waves within the permissible limits to follow these algorithms. This paper attempts to utilize electromagnetic waves at resonance frequency of 2.4 GHz for underwater communication. The results verify that the implementation of Alive-in-Range MAC protocol has reduced the average end to end delay significantly making it appropriate for critical and real time data monitoring. This work proves the suitability of electromagnetic waves as an effective alternative for underwater wireless communication. The main objective is to mitigate sink neighbourhood problem, distance constrained mobile sink problem and to reduce the average end to end delay by implementing Alive-in-Range (AR-MAC medium access control protocol in underwater sensor networks and to draw the attention of researchers in this area.

  12. [Urban Health (StadtGesundheit): The Wider Perspective Exemplified by the City State of Hamburg].

    Science.gov (United States)

    Fehr, R; Fertmann, R; Stender, K-P; Lettau, N; Trojan, A

    2016-09-01

    Public health and city planning have common roots, and in many places they are now reuniting under the heading of urban health. To organize this field adequately requires a broad, integrative view of medical care, health promotion, and health in all urban policies. Given current crises and developments including climate change and globalization, such a wider perspective should also be useful for Germany. Using the City State of Hamburg as an example and combining historic and systematic approaches, we explore the preconditions for in-depth analyses. Our results show that health is a significant topic of Hamburg urban policy, featuring a broad range of structures, processes and actors, both within the health sector and far beyond. Health promotion over the last 30 years evolved notably from a niche topic into an established field with remarkable cooperative structures. The tradition of comprehensive reporting on urban health in Hamburg that was initiated more than 200 years ago is no longer alive today. However, local health reporting keeps integrating a wide range of diverse topics. Communication among the Hamburg health actors - beyond straightforward medical quality assurance - does not seem to focus on critical evaluations, e. g. concerning social and ecologic sustainability. A prerequisite for in-depth analyses including external comparisons is to secure permanent access to relevant sources. Robust approaches to this end, however, seem to be lacking. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Long-term high frequency measurements of ethane, benzene and methyl chloride at Ragged Point, Barbados: Identification of long-range transport events

    Directory of Open Access Journals (Sweden)

    A.T. Archibald

    2015-09-01

    Full Text Available AbstractHere we present high frequency long-term observations of ethane, benzene and methyl chloride from the AGAGE Ragged Point, Barbados, monitoring station made using a custom built GC-MS system. Our analysis focuses on the first three years of data (2005–2007 and on the interpretation of periodic episodes of high concentrations of these compounds. We focus specifically on an exemplar episode during September 2007 to assess if these measurements are impacted by long-range transport of biomass burning and biogenic emissions. We use the Lagrangian Particle Dispersion model, NAME, run forwards and backwards in time to identify transport of air masses from the North East of Brazil during these events. To assess whether biomass burning was the cause we used hot spots detected using the MODIS instrument to act as point sources for simulating the release of biomass burning plumes. Excellent agreement for the arrival time of the simulated biomass burning plumes and the observations of enhancements in the trace gases indicates that biomass burning strongly influenced these measurements. These modelling data were then used to determine the emissions required to match the observations and compared with bottom up estimates based on burnt area and literature emission factors. Good agreement was found between the two techniques highlight the important role of biomass burning. The modelling constrained by in situ observations suggests that the emission factors were representative of their known upper limits, with the in situ data suggesting slightly greater emissions of ethane than the literature emission factors account for. Further analysis was performed concluding only a small role for biogenic emissions of methyl chloride from South America impacting measurements at Ragged Point. These results highlight the importance of long-term high frequency measurements of NMHC and ODS and highlight how these data can be used to determine sources of emissions

  14. A new hybrid phononic crystal in low frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z., E-mail: zhangz@dlut.edu.cn; Han, X.K.

    2016-11-25

    A novel hybrid phononic crystal is designed to obtain wider band gaps in low frequency range. The hybrid phononic crystal consists of rubber slab with periodic holes and plumbum stubs. In comparison with the phononic crystal without periodic holes, the new designed phononic crystal can obtain wider band gaps and better vibration damping characteristics. The wider band gap can be attributed to the interaction of local resonance and Bragg scattering. The controlling of the BG is explained by the strain energy of the hybrid PC and the introduced effective mass. The effects of the geometrical parameters and the shapes of the stubs and holes on the controlling of waves are further studied. - Highlights: • A novel hybrid PC structure is proposed in current work. The new designed hybrid PC shows wider BG in low frequency range and better vibration damping characteristics. • Strain energy and effective mass are introduced for the investigations on the mechanism of the controlling of BGs in PC structure. • The effects of the geometrical parameters and the shapes of the stubs and holes on the controlling of waves are further studied for optimal design.

  15. Mutual relationship of oscillations in the frequency range 3.6 mHz to 22 mHz in the solar chromosphere

    Directory of Open Access Journals (Sweden)

    Anđić A.

    2006-01-01

    Full Text Available High frequency acoustic oscillations were suggested as the source of mechanical heating in the chromosphere. In this work the radial component of the oscillations in the frequency interval 3 mHz to 22 mHz are investigated. The observations were performed using "D spectrometry on the Fe I neutral spectral line at 543:45 nm. The high frequency oscillations of different frequencies appear to be associated with different spatial scales. It seems that different sources produce high and low frequency acoustic oscillations.

  16. Identification of low and high frequency ranges for heart rate variability and blood pressure variability analyses using pharmacological autonomic blockade with atropine and propranolol in swine.

    Science.gov (United States)

    Poletto, Rosangela; Janczak, Andrew M; Marchant-Forde, Ruth M; Marchant-Forde, Jeremy N; Matthews, Donald L; Dowell, Carol A; Hogan, Daniel F; Freeman, Lynetta J; Lay, Donald C

    2011-05-03

    Understanding autonomic nervous system functioning, which mediates behavioral and physiological responses to stress, offers great potential for assessing farm animal stress and welfare. Evaluation of heart rate variability (HRV) and blood pressure variability (BPV), using time and frequency domain analyses may provide a sensitive and reliable measure of affective states and stress-mediated changes in sympathetic and parasympathetic tones. The aim of this research was to define low (LF) and high frequency (HF) power spectral ranges using pharmacological autonomic blockade, and to examine HRV and BPV parameter changes in response to atropine and propranolol in swine. Ten, 13-week old, barrows (n=6) and gilts (n=4) underwent surgery to place an intra-cardiac electrode and a blood pressure catheter attached to a biotelemetric transmitter; pigs had a 3-week recovery period prior to data collection. Each pig was subjected to administration of 4 intravenous (i.v.) drug treatments: a control treatment, 3 mL of saline, and 3 blockade treatments; 0.1 mg/kg of atropine, 1.0 mg/kg of propranolol, and .1 mg/kg of atropine together with 1.0 mg/kg of propranolol. All treatments were delivered by injection in the jugular vein with a minimum of 48 h between individual treatments. Behavior, ECG and blood pressure data were recorded continuously for a total of 1h, from 30 min pre-injection to 30 min post-injection. For data analyses, two 512-beat intervals were selected for each treatment while the pig was lying and inactive. The first interval was selected from the pre-injection period (baseline), and the second was selected between 10 and 30 min post-injection. Time and frequency domain (power spectral density) analyses were performed on each data interval. Subsequent, LF and HF bands from the power spectral densities were defined based on general linear and regression analyses. The HRV and BPV were computed with a covariate (baseline) factorial analysis of treatment by sex

  17. 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).

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

    Energy Technology Data Exchange (ETDEWEB)

    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 {alpha}-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 {alpha}-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) 47 refs.

  19. The wider importance of cadavers: educational and research diversity from a body bequest program.

    Science.gov (United States)

    Cornwall, Jon; Stringer, Mark D

    2009-10-01

    The debate surrounding the use of cadavers in teaching anatomy has focused almost exclusively on the pedagogic role of cadaver dissection in medical education. The aim of this study was to explore the wider aspects of a body bequest program for teaching and research into gross anatomy in a University setting. A retrospective audit was undertaken on body donation and the use of cadaver specimens for teaching and research at our institution between 1876 and 2009. The body bequest program, first established in 1943, now receives more than 40 donations per year. In addition to the medical course, nine other University degrees and courses currently use cadaver specimens for gross anatomy; four of these are research degrees and the remainder undergraduate degrees and courses. The use of cadaver specimens by non-University groups has also increased, particularly during the past decade, such that there are now 16 different groups using cadaver specimens for instructional courses; most of these are professional medical courses. The use of cadavers for both research and teaching may encourage a more evidence-based approach to clinical anatomy. This unique audit, spanning more than a century of anatomy education within a single University Medical School, highlights the utility of a robust body bequest program and the wide range of students and health professionals who interact with this precious resource.

  20. Influence Of Terahertz Range Electromagnetic Radiation At Molecular Spectrum Frequency Of 150+0,75 Ghz Nitric Oxide On Microcirculation Morphofunctional Disturbances In White Rats In Condition Of Acute And Prolonged Stress

    Directory of Open Access Journals (Sweden)

    M.O. Kurtukova

    2009-12-01

    Full Text Available The effect of electromagnetic radiation of terahertz range at frequency of emission and absorption molecular spectrum of 150+0,75GHz nitric oxide on morphofunctional changes of microcirculation and tissue structure in animals in condition of acute and prolonged immobilization stress has been studied. It has shown that the influence of electromagnetic waves at these frequencies causes activity decrease of hypothalamic-pituitary-adrenal and tireoyd axis of stress reaction. It has been determined that terahertz range waves at frequency of nitric oxide are liable to restore disturbances of intravascular, vascular and extravascular components of microcirculation and also have histoprotective effect

  1. The infancy of particle accelerators life and work of Rolf Wideröe

    CERN Document Server

    1994-01-01

    by Pedro Waloschek The following autobiographical account of Rolf Wideröe's life and work is based on manuscripts and letters written by hirnself, most ofthem especially for this report. Data from audio and video recordings with his illustrations and from my notes taken during aseries ofmeetings between the two ofus were also included. Rolf Wideröe gave me access to many of his publications and to other documents from which I have extracted further information. I have compiled, edited and, where necessary, put the texts in chronological order. These were then corrected and supplemented by Rolf Wideröe during the course of several readings. The English translation was also checked by Wideröe and we were able to add some improvements and corrections. This account there­ fore stands as an authorised biography and is written in the first person. Mrs. Wideröe's accurate memory was of great assistance. The emphasis has been on RolfWideröe's life story and the first developments which led to modem particle ac...

  2. 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%.

  3. 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

  4. 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.

  5. Involving people with diabetes and the wider community in diabetes research: a realist review protocol.

    Science.gov (United States)

    Harris, Janet; Graue, Marit; Dunning, Trisha; Haltbakk, Johannes; Austrheim, Gunhild; Skille, Nina; Rokne, Berit; Kirkevold, Marit

    2015-11-04

    Patient and public involvement in diabetes research is now actively encouraged in different countries because it is believed that involving people with experience of the condition will improve the quality and relevance of the research. However, reviews of patient involvement have noted that inadequate resources, patients' and communities' lack of research knowledge, and researchers' lack of skills to involve patients and communities in research may present significant contextual barriers. Little is known about the extent of patient/community involvement in designing or delivering interventions for people with diabetes. A realist review of involvement will contribute to assessing when, how and why involvement works, or does not work, to produce better diabetes interventions. This protocol outlines the process for conducting a realist review to map how patients and the public have been involved in diabetes research to date. The review questions ask the following: How have people with diabetes and the wider community been involved in diabetes research? What are the characteristics of the process that appear to explain the relative success or failure of involvement? How has involvement (or lack of involvement) in diabetes research influenced the development and conduct of diabetes research? The degree of support in the surrounding context will be assessed alongside the ways in which people interact in different settings to identify patterns of interaction between context, mechanisms and outcomes in different research projects. The level and extent of the involvement will be described for each stage of the research project. The descriptions will be critically reviewed by the people with diabetes on our review team. In addition, researchers and patients in diabetes research will be asked to comment. Information from researcher-patient experiences and documents will be compared to theories of involvement across a range of disciplines to create a mid-range theory

  6. The potential of the gyrotrons for development of the sub-terahertz and the terahertz frequency range - A review of novel and prospective applications

    Energy Technology Data Exchange (ETDEWEB)

    Idehara, T.; Saito, T.; Ogawa, I.; Mitsudo, S.; Tatematsu, Y. [Research Center for Development of Far Infrared Region, University of Fukui, 3-9-1 Bunkyo, 910-8507 Fukui (Japan); Sabchevski, S. [Research Center for Development of Far Infrared Region, University of Fukui, 3-9-1 Bunkyo, 910-8507 Fukui (Japan); Institute of Electronics of the Bulgarian Academy of Sciences, 72 Tzarigradsko Shose Blvd., 1784 Sofia (Bulgaria)], E-mail: sabch@ie.bas.bg

    2008-12-31

    Some recent advancements in the development of powerful high frequency gyrotrons that generate coherent radiation in the sub-terahertz and terahertz regions of the electromagnetic spectrum as well as their typical and novel applications are presented and discussed.

  7. Identification of low and high frequency ranges for heart rate variability and blood pressure variability analyses using pharmacological autonomic blockade with atropine and propranolol in swine.

    Science.gov (United States)

    Understanding autonomic nervous system functioning, which mediates behavioral and physiological responses to stress, offers great potential for evaluation of farm animal stress and welfare. Evaluation of heart rate variability (HRV) and blood pressure variability (BPV), using time and frequency doma...

  8. 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...

  9. 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 ...

  10. Frequency Adaptability of Harmonics Controllers for Grid-Interfaced Converters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2017-01-01

    A wider spread adoption of power electronic converters interfaced renewable energy systems has brought more attention to harmonic issues to the electrical grid, and means are taken to improve it in the control. More advanced closed-loop harmonic controllers are thus demanded to enhance...... 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...... the renewable energy integration in order to be grid-friendly. However, usually being treated as a constant factor in the design of harmonic controllers, the grid frequency varies with the generation-load imbalance, and thus may lead to deterioration of the power quality. This paper explores the frequency...

  11. The interplay between local and wider geographical uses of directional terms in West Greenlandic

    DEFF Research Database (Denmark)

    Trondhjem, Naja Blytmann; Fortescue, Michael David

    referring to a wider geographical area. This is in part due to the influence of the cardinal system of Danish (and the other European languages), but is also inherent in the native system itself as it can be reconstructed prior to contact with the West. How this ambiguity pans out (and is contextually...

  12. On the dispersion management of fluorite whispering-gallery mode resonators for Kerr optical frequency comb generation in the telecom and mid-infrared range

    CERN Document Server

    Lin, Guoping

    2015-01-01

    Optical whispering gallery mode (WGM) resonators have been very attracting platforms for versatile Kerr frequency comb generations. We report a systematic study on the material dispersion of various optical materials that are capable of supporting quality factors above $10^9$. Using an analytical approximation of WGM resonant frequencies in disk resonators, we investigate the effect of the geometry and transverse mode order on the total group-velocity dispersion ($GVD$). We demonstrate that the major radii and the radial mode indices play an important role in tailoring the $GVD$ of WGM resonators. In particular, our study shows that in WGM disk-resonators, the polar families of modes have very similar $GVD$, while the radial families of modes feature dispersion values that can differ by up to several orders of magnitude. The effect of these giant dispersion shifts are experimentally evidenced in Kerr comb generation with magnesium fluoride. From a more general perspective, this critical feature enables to pus...

  13. 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.

  14. Electromagnetic interference shielding effectiveness of composite carbon nanotube macro-film at a high frequency range of 40 GHz to 60 GHz

    Directory of Open Access Journals (Sweden)

    Zi Ping Wu

    2015-06-01

    Full Text Available The electromagnetic interference (EMI shielding effectiveness (SE of carbon nanotube (CNT macro-film that is adhered to common cloth to maintain the light weight, silk-like quality, and smooth surface of the material for EMI shielding is investigated. The results show that a high and stable EMI SE of 48 dB to 57 dB at 40 GHz to 60 GHz was obtained by the macro-film with a thickness of only ∼4 μm. The composite CNT macro-film is easily manipulated, and its EMI property is significantly different from that of traditional electromagnetic shielding materials that show a lower EMI SE with increasing frequency. For example, the EMI SE of Cu foils decrease from 75 dB to 35 dB as frequency increases from 25 GHz to 60 GHz. Considering their stable and outstanding EMI SE and easy manipulation, the composite CNT macro-films are expected to have potential applications in shielding against millimeter waves.

  15. Effect of the incident power on permittivity, losses and tunability of BaSrTiO3 thin films in the microwave frequency range

    Science.gov (United States)

    Nadaud, Kevin; Borderon, Caroline; Renoud, Raphaël; Ghalem, Areski; Crunteanu, Aurelian; Huitema, Laure; Dumas-Bouchiat, Frédéric; Marchet, Pascal; Champeaux, Corinne; Gundel, Hartmut W.

    2017-05-01

    Domain wall motions in ferroelectrics participate to the material's complex permittivity and are responsible for their sensitivity of the dielectric properties to the driving electric field and thus to the incident power at microwave frequencies. In the present study, the dependence of the permittivity, the dielectric losses, and the tunability of Ba2/3Sr1/3TiO3 (BST) thin films on the incident power and on the bias fields is examined at a frequency of 500 MHz. While the domain wall motion participates only slightly to the permittivity (influences the losses due to its very dissipative behavior. As a consequence, the Figure of Merit (FoM, the ratio between tunability and dielectric losses) of the material depends on the applied microwave power. In the present study, a decrease in the FoM from 29 to 21 is observed for an incident power varying from -20 dBm to 5 dBm. When characterizing ferroelectric materials, the incident power has to be considered; moreover, domain wall motion effects should be limited in order to achieve a high FoM and less power sensitivity.

  16. Millimeter Wave Systems for Airports and Short-Range Aviation Communications: A Survey of the Current Channel Models at mmWave Frequencies

    Science.gov (United States)

    Khatun, Mahfuza; Mehrpouyan, Hani; Matolak, David; Guvenc, Ismail

    2017-01-01

    Millimeter-wave (mmWave) communications will play a key role in enhancing the throughput, reliability, and security of next generation wireless networks. These advancements are achieved through the large bandwidth available in this band and through the use of highly directional links that will be used to overcome the large pathloss at these frequencies. Although the terrestrial application of mmWave systems is advancing at a rapid pace, the use of mmWave communication systems in aviation systems or airports is still in its infancy. This can be attributed to the challenges related to radio technology and lack of development, and characterization of mmWave wireless channels for the aviation field and the airport environment. Consequently, one of our goals is to develop methodologies that support mmWave air to ground links, and various links at airports, by applying new localization schemes that allow for application of highly directional links that can be deployed over longer distances despite the high path loss at mmWave frequencies. However, a very thorough understanding of the mmWave channel models are needed to enable such new applications. To this end, in this paper, we present a survey of the current channel models in the mmWave band. The 3-dimensional statistical channel model is also reviewed and its parameters and typical characteristics for this model are identified and computed through simulation for the Boise metropolitan area.

  17. The ethics of drug development and promotion: the need for a wider view.

    Science.gov (United States)

    Brody, Howard

    2012-11-01

    Ethical issues at the interface between the medical profession and the pharmaceutical industry have generally been approached from the vantage point of medical professionalism, with a focus on conflict of interest as the key ethical concern. Although conflicts of interest remain important, other ethical issues may be obscured unless a wider perspective is adopted. Besides medical professionalism, the ethics of the clinical therapeutic relationship, ethics of public health, and business ethics all provide additional insights.

  18. Cetaceans and gillnet fisheries in Mexico, Central America and the Wider Caribbean: a preliminary review

    OpenAIRE

    Vidal, O.; Van Waerebeek, K.; Findley, L.T.

    1994-01-01

    This paper reviews published and unpublished information on the mortality of cetaceans in gillnets in Mexico, Central America and the wider Caribbean. Data on this incidental mortality are provided from only nine of the 36 nations in the area (Colombia, the Dominican Republic. French Guiana, Honduras, Mexico. Panama, Surinam, Trinidad and Tobago, and Venezuela); the lack of mortality records from the other countries reflects poor or non-existent documentation. We surveyed those types of passi...

  19. On a simple attack, limiting the range transmission of secret keys in a system of quantum cryptography based on coding in a sub-carrier frequency

    Science.gov (United States)

    Klimov, A. N.; Kulik, S. P.; Molotkov, S. N.; Potapova, T. A.

    2017-03-01

    In the paper by Gleim et al (2016 Opt. Express 24 2619), it was declared that the system of quantum cryptography, exploiting quantum key distribution (QKD) protocol BB84 with the additional reference state and encoding in a sub-carrier, is able to distribute secret keys at a distance of 210 km. The following shows that a simple attack realized with a beam splitter results in a loss of privacy of the keys over substantially smaller distances. It turns out that the actual length of the secret key transmission for the QKD system encoding in the sub-carrier frequency is ten times less than that declared in Gleim et al (2016 Opt. Express 24 2619). Therefore it is impossible to safely use the keys when distributed at a larger length of the communication channel than shown below. The maximum communication distance does not exceed 22 km, even in the most optimistic scenario.

  20. A new ion cyclotron range of frequency scenario for bulk ion heating in deuterium-tritium plasmas: How to utilize intrinsic impurities in our favour

    Energy Technology Data Exchange (ETDEWEB)

    Kazakov, Ye. O.; Ongena, J.; Van Eester, D.; Lerche, E.; Messiaen, A. [Laboratory for Plasma Physics, LPP-ERM/KMS, EUROfusion Consortium Member, Brussels (Belgium); Bilato, R. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Dumont, R. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Mantsinen, M. [Catalan Institution for Research and Advanced Studies, Barcelona (Spain); Barcelona Supercomputing Center (BSC), Barcelona (Spain)

    2015-08-15

    A fusion reactor requires plasma pre-heating before the rate of deuterium-tritium fusion reactions becomes significant. In ITER, radio frequency (RF) heating of {sup 3}He ions, additionally puffed into the plasma, is one of the main options considered for increasing bulk ion temperature during the ramp-up phase of the pulse. In this paper, we propose an alternative scenario for bulk ion heating with RF waves, which requires no extra {sup 3}He puff and profits from the presence of intrinsic Beryllium impurities in the plasma. The discussed method to heat Be impurities in D-T plasmas is shown to provide an even larger fraction of fuel ion heating.

  1. 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).

  2. 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

  3. Micromachined components for terahertz frequency applications

    CERN Document Server

    Parkhurst, G M

    2001-01-01

    lithographic technology for the fabrication of terahertz circuits, the integration of an active solid state device is explored. The device chosen for this work is the resonant tunnel diode (RTD). Some background discussion of the operation of these devices as oscillators is presented, and techniques for full integration of devices into a waveguide, using processes which are completely compatible with semiconductor manufacturing technology, are explored experimentally. Two main problems prevent the use of the terahertz frequency band (defined for present purposes as 100GHz - 10THz) in a wider range of applications. The first is the absence of a convenient, cheap solid-state source of power and the second is the significant cost of conventional passive components. In this Thesis, the second issue is addressed in detail, describing developments in the fabrication and characterisation of low cost lithographically-produced terahertz frequency passive components. An extensive study of the use of ultra-thick UV phot...

  4. A 400-mV 2.4-GHz frequency-shift keying transmitter using a capacitor switch across a transformer for a wide tuning range voltage-controlled oscillator

    Science.gov (United States)

    Miyahara, Yasunori; Ishikawa, Keisuke; Kuroda, Tadahiro

    2017-04-01

    We use a simple directly modulated closed loop to develop a 2.1-mW, 2.4-GHz frequency-shift keying (FSK) transmitter that operates on 400-mV DC supply. Connecting a capacitor bank switch via a transformer in the voltage control oscillator (VCO) to the frequency-divider circuit expands the frequency tuning range without reducing VCO performance. A prototype was fabricated using the 65-nm standard CMOS process with a chip size of 1.65 × 1.85 mm2. A modulation output signal spectrum of -42 dBc at 1.5 MHz with -6 dBm at the PA buffer output terminal; moreover, a VCO phase noise of -101 dBc/Hz at 1 MHz is achieved. The FSK transmitter can readily use voltages supplied by harvested energy because of the low power consumption of the sensor network.

  5. 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.

  6. 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.

  7. Electronic spectrum in the visible frequency range of UF/sub 4/ molecules isolated in solid neon, and its interpretation in the crystal-field approximation

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, A.A.; Golubev, Y.M.

    1987-09-01

    The matrix isolation method is used to obtain the spectra of molecules in solid neon in the 1000--400-nm range. All the recorded bands are referred to transitions within the 5f /sup 2/ configuration of U/sup 4 +/ ion in the field of four fluorine ions. The interpretation assumes the case of a weak crystal field in which the terms of U/sup 4 +/ ion with different J are not mixed up. It is concluded that the UF/sub 3/ molecule has the structure of either a tetrahedron or a slightly distorted tetrahedron.

  8. 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.

  9. 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.

  10. Fruit and vegetable exposure in children is linked to the selection of a wider variety of healthy foods at school.

    Science.gov (United States)

    Korinek, Elizabeth V; Bartholomew, John B; Jowers, Esbelle M; Latimer, Lara A

    2015-10-01

    Schools often offer healthy fruits and vegetables (FV) and healthy entrées. However, children may resist these efforts due to a lack of familiarity with the offerings. While numerous exposures with a food increase its liking, it may be that an exposure to a variety of FV at home leads to greater willingness to select other foods - even those that are unrelated to those eaten at home. As an initial test of this possibility, this study was designed to examine how self-reports of exposure and consumption of various FV were associated with the selection of FV and lunch entrées at school. Participants (n = 59) were a convenience sample of elementary children. A median split was used to place students into high- and low-exposure groups for self-reports of both exposure and consumption at home. The primary dependent variables were self-reports of selecting FV at school; the children's absolute and relative ratings of eight 'healthier' lunch entrées; and self-reports of selecting these entrées. These entrées were recently added to the school menu and, therefore, tended to be less familiar to children. Food ratings were collected through taste exposures conducted at school. Results indicate that children who reported more frequent exposure to FV at home consumed a wider variety of FV at school and were more likely to report selecting 'healthier' entrées at school lunch. These data suggest that exposure to, and the consumption of, a variety of FV may make children more willing to select a wider range of FV and other healthy entrées. © 2013 John Wiley & Sons Ltd.

  11. Feature extraction of micro-motion frequency and the maximum wobble angle in a small range of missile warhead based on micro-Doppler effect

    Science.gov (United States)

    Li, M.; Jiang, Y. S.

    2014-11-01

    Micro-Doppler effect is induced by the micro-motion dynamics of the radar target itself or any structure on the target. In this paper, a simplified cone-shaped model for ballistic missile warhead with micro-nutation is established, followed by the theoretical formula of micro-nutation is derived. It is confirmed that the theoretical results are identical to simulation results by using short-time Fourier transform. Then we propose a new method for nutation period extraction via signature maximum energy fitting based on empirical mode decomposition and short-time Fourier transform. The maximum wobble angle is also extracted by distance approximate approach in a small range of wobble angle, which is combined with the maximum likelihood estimation. By the simulation studies, it is shown that these two feature extraction methods are both valid even with low signal-to-noise ratio.

  12. Development and numerical characterization of a new standing wave ultrasonic motor operating in the 30-40kHz frequency range.

    Science.gov (United States)

    Hou, Xiaoyan; Lee, Heow Pueh; Ong, Chong Jin; Lim, Siak Piang

    2013-07-01

    The purpose of this research is to present a new design of standing-wave ultrasonic motor. This motor uses three piezoelectric actuating blocks which deform appropriately when powered up. The deformations of the blocks in ultrasonic range are internally amplified via the design of the motor by about 80 times and collectively yield an elliptical trajectory for the driving head of the motor. Finite Element Analysis using ANSYS was performed for both dynamic analysis and optimization of a prototype motor. The numerical results verified that at steady state, the motor can achieve vibrations in micro-meter level and the velocity can reach decimeter scale, satisfying the fast speed requirement as a positioning actuator. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Alpine lakes preserve mineral dust signatures: Implications for long-range mineral dust transport and Last Glacial Maximum (LGM) tornado frequency in the United States

    Science.gov (United States)

    Bhattacharya, A.; Lora, J. M.; Pollen, A.; Vollmer, T.; Thomas, M.; Leithold, E. L.; Mitchell, J.; Tripati, A.

    2016-12-01

    contribution. Most importantly, we find that during the Last Glacial Maximum (LGM) the Great Plains may not have witnessed an increase in the incidence of tornado frequency. Acknowledgements: James Sigman, Jacob Ashford, Jason Neff and Amato Evan

  14. 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.

  15. Opportunities and challenges in the wider adoption of liver and interconnected microphysiological systems.

    Science.gov (United States)

    Hughes, David J; Kostrzewski, Tomasz; Sceats, Emma L

    2017-10-01

    Liver disease represents a growing global health burden. The development of in vitro liver models which allow the study of disease and the prediction of metabolism and drug-induced liver injury in humans remains a challenge. The maintenance of functional primary hepatocytes cultures, the parenchymal cell of the liver, has historically been difficult with dedifferentiation and the consequent loss of hepatic function limiting utility. The desire for longer term functional liver cultures sparked the development of numerous systems, including collagen sandwiches, spheroids, micropatterned co-cultures and liver microphysiological systems. This review will focus on liver microphysiological systems, often referred to as liver-on-a-chip, and broaden to include platforms with interconnected microphysiological systems or multi-organ-chips. The interconnection of microphysiological systems presents the opportunity to explore system level effects, investigate organ cross talk, and address questions which were previously the preserve of animal experimentation. As a field, microphysiological systems have reached a level of maturity suitable for commercialization and consequent evaluation by a wider community of users, in academia and the pharmaceutical industry. Here scientific, operational, and organizational considerations relevant to the wider adoption of microphysiological systems will be discussed. Applications in which microphysiological systems might offer unique scientific insights or enable studies currently feasible only with animal models are described, and challenges which might be addressed to enable wider adoption of the technologies are highlighted. A path forward which envisions the development of microphysiological systems in partnerships between academia, vendors and industry, is proposed. Impact statement Microphysiological systems are in vitro models of human tissues and organs. These systems have advanced rapidly in recent years and are now being

  16. Systemic Planning: Dealing with Complexity by a Wider Approach to Planning

    DEFF Research Database (Denmark)

    Leleur, Steen

    2005-01-01

    On the basis of a new book Systemic Planning this paper addresses systems thinking and complexity in a context of planning. Specifically, renewal of planning thinking on this background is set out as so-called systemic planning (SP). The principal concern of SP is to provide principles...... and methodology that can be helpful for planning under circumstances characterised by complexity and uncertainty. It is argued that compared to conventional, planning – referred to as systematic planning - there is a need for a wider, more systemic approach to planning that is better suited to current real...

  17. 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.

  18. 76 FR 19380 - Notice of Entry Into Effect of MARPOL Annex V Wider Caribbean Region Special Area

    Science.gov (United States)

    2011-04-07

    ... SECURITY Coast Guard Notice of Entry Into Effect of MARPOL Annex V Wider Caribbean Region Special Area... effect of discharge requirements from ships in the Wider Caribbean Region (WCR) special area (SA) as...(b), the Coast Guard announces the May 1, 2011 date for entry into effect of discharge requirements...

  19. Population structure and connectivity of the mountainous star coral, Orbicella faveolata, throughout the wider Caribbean region.

    Science.gov (United States)

    Rippe, John P; Matz, Mikhail V; Green, Elizabeth A; Medina, Mónica; Khawaja, Nida Z; Pongwarin, Thanapat; Pinzón C, Jorge H; Castillo, Karl D; Davies, Sarah W

    2017-11-01

    As coral reefs continue to decline worldwide, it becomes ever more necessary to understand the connectivity between coral populations to develop efficient management strategies facilitating survival and adaptation of coral reefs in the future. Orbicella faveolata is one of the most important reef-building corals in the Caribbean and has recently experienced severe population reductions. Here, we utilize a panel of nine microsatellite loci to evaluate the genetic structure of O. faveolata and to infer connectivity across ten sites spanning the wider Caribbean region. Populations are generally well-mixed throughout the basin (FST = 0.038), although notable patterns of substructure arise at local and regional scales. Eastern and western populations appear segregated with a genetic break around the Mona Passage in the north, as has been shown previously in other species; however, we find evidence for significant connectivity between Curaçao and Mexico, suggesting that the southern margin of this barrier is permeable to dispersal. Our results also identify a strong genetic break within the Mesoamerican Barrier Reef System associated with complex oceanographic patterns that promote larval retention in southern Belize. Additionally, the diverse genetic signature at Flower Garden Banks suggests its possible function as a downstream genetic sink. The findings reported here are relevant to the ongoing conservation efforts for this important and threatened species, and contribute to the growing understanding of large-scale coral reef connectivity throughout the wider Caribbean.

  20. Participation, process quality, and performance of marine protected areas in the wider Caribbean.

    Science.gov (United States)

    Dalton, Tracey; Forrester, Graham; Pollnac, Richard

    2012-06-01

    Throughout the wider Caribbean, marine protected areas (MPAs) are rapidly gaining momentum as a conservation tool, but management performance of existing MPAs is considered low. To enhance MPA management performance, stakeholders are increasingly being invited to discuss, debate, and develop rules about how people should interact with marine ecosystems. Using social and ecological data from a rapid assessment of 31 MPAs and their associated communities in the wider Caribbean, this study investigates stakeholder participation in MPA planning and management, and how participants' views of process quality relate to MPA performance. Findings indicate that (1) participants tended to be male, resource users, participate in community organizations, and have lived fewer years in the community associated with an MPA than non-participants; (2) simply participating was not associated with perceptions of the social and ecological performance of MPAs, however, perceptions of process quality were positively related to views of performance; and (3) resource users' perceptions of an MPA's ecological performance were likely shaped by a variety of factors. Conservation practitioners should be aware that participatory MPA processes are complex and require careful planning if they are to contribute positively to marine conservation efforts.

  1. The Wider Impacts of Universities: Habermas on Learning Processes and Universities

    Directory of Open Access Journals (Sweden)

    Jesper Eckhardt Larsen

    2013-06-01

    Full Text Available The discourse of reform in higher education tends to focus narrowly on employability and the relationship between higher education and the labor market. Universities as research institutions are now considered solely in the dominant discourse of innovation. This way of conceiving universities is inspired by functionalist theory that focuses on the imperatives of a knowledge economy. Taking a departure in the theory of society developed by Jürgen Habermas this paper seeks to provide a theoretical framework for an empirical comparative analysis on the wider societal impact of universities. It is the argument that the wider impacts of higher education and research at universities must be seen in a more complex vision of modern societies. The paper is thus primarily a re-reading of Habermas’ critique of functionalist views of the university and an application of Habermas’ critique on current issues in the debates on higher education. A special discussion will be taken on issues of the self in view of the current tendencies to regard all education from the standpoint of the economic outputs.

  2. Employee Attitudes Toward Aggression in Persons with Dementia: Readiness for Wider Adoption of Person-Centered Frameworks.

    Science.gov (United States)

    Burshnic, Vanessa Louise; Douglas, Natalie; Barker, Robert Michael

    2018-01-10

    Implementing person-centered care requires shared attitudes, beliefs, and values among all care employees. Existing research has failed to examine the attitudes of non-nursing employees. This study examined attitudes toward aggression among nursing and non-nursing employees to address gaps in existing research and assess readiness for wider adoption of person-centered frameworks. The Management of Aggression in People with Dementia Attitude Questionnaire was used to survey attitudes of employees in Michigan-based nursing homes. Overall, employees preferred person-centered over standard approaches. Job title was a significant predictor of paradigm support. Frontline employees were found to support person-centered attitudes the least. Wide-ranging responses were noted within employee groups. Job title may influence the degree to which an employee supports and utilizes person-centered approaches. Employees with the most contact with persons with dementia may be the least likely to implement person-centered approaches. In contrast to prior studies, years of experience was not a significant predictor of attitude toward aggressive behavior. Wide-ranging responses indicate that employee attitudes are varied and complex. Person-centered approaches should be trained within care areas rather than individual employee groups. Programs should be interdisciplinary and seek to establish a shared understanding of person-centered beliefs and values. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. Accurate step-FMCW ultrasound ranging and comparison with pulse-echo signaling methods

    Science.gov (United States)

    Natarajan, Shyam; Singh, Rahul S.; Lee, Michael; Cox, Brian P.; Culjat, Martin O.; Grundfest, Warren S.; Lee, Hua

    2010-03-01

    This paper presents a method setup for high-frequency ultrasound ranging based on stepped frequency-modulated continuous waves (FMCW), potentially capable of producing a higher signal-to-noise ratio (SNR) compared to traditional pulse-echo signaling. In current ultrasound systems, the use of higher frequencies (10-20 MHz) to enhance resolution lowers signal quality due to frequency-dependent attenuation. The proposed ultrasound signaling format, step-FMCW, is well-known in the radar community, and features lower peak power, wider dynamic range, lower noise figure and simpler electronics in comparison to pulse-echo systems. In pulse-echo ultrasound ranging, distances are calculated using the transmit times between a pulse and its subsequent echoes. In step-FMCW ultrasonic ranging, the phase and magnitude differences at stepped frequencies are used to sample the frequency domain. Thus, by taking the inverse Fourier transform, a comprehensive range profile is recovered that has increased immunity to noise over conventional ranging methods. Step-FMCW and pulse-echo waveforms were created using custom-built hardware consisting of an arbitrary waveform generator and dual-channel super heterodyne receiver, providing high SNR and in turn, accuracy in detection.

  4. Efficient Generation of Frequency-Multiplexed Entangled Single Photons

    Science.gov (United States)

    Qiu, Tian-Hui; Xie, Min

    2016-12-01

    We present two schemes to generate frequency-multiplexed entangled (FME) single photons by coherently mapping photonic entanglement into and out of a quantum memory based on Raman interactions. By splitting a single photon and performing subsequent state transfer, we separate the generation of entanglement and its frequency conversion, and find that the both progresses have the characteristic of inherent determinacy. Our theory can reproduce the prominent features of observed results including pulse shapes and the condition for deterministically generating the FME single photons. The schemes are suitable for the entangled photon pairs with a wider frequency range, and could be immune to the photon loss originating from cavity-mode damping, spontaneous emission, and the dephasing due to atomic thermal motion. The sources might have significant applications in wavelength-division-multiplexing quantum key distribution.

  5. Radio Frequency Ranging for Swarm Relative Localization

    Science.gov (United States)

    2017-10-01

    Path Loss GPS Global Positioning System ID identification IDE integrated development environment IO input/output ISM industrial, scientific, and...information. This is particularly important in GPS-denied environments where there are limited positioning options. Many applications exist for relative...4 Fig. 3 Atmel sampling rate tests results .......................................................... 6 Fig. 4 Zoomed medium and slow

  6. Analysis on characteristic and application of THz frequency comb and THz sub-comb

    Energy Technology Data Exchange (ETDEWEB)

    Liu Pengxiang; Xu Degang; Yao Jianquan, E-mail: xudegang@tju.edu.cn [Institute of Laser and Optoelectronics, College of Precision Instruments and Opto-electronic Engineering, Tianjin University, Tianjin, 300072 (China); Key Laboratory of Opto-electronic Information Science and Technology, Ministry of Education, Tianjin, 300072 (China)

    2011-02-01

    In this paper, we proposed a method for THz sub-comb generation based on spectral interference. The result of our calculation indicated that the THz pulse train, generated by surface-emitted optical rectification of femtosecond (fs) laser pulse in periodically poled lithium niobate (PPLN), has a comb-like spectrum. The characteristic of this THz sub-comb was analyzed both in frequency and time domain. Compared with the THz frequency comb emitted by a photoconductive antenna (PCA), THz sub-comb has a lower spectral resolution and wider free spectral range. Thus it could be an ideal source for wavelength division multiplexing (WDM) in THz wireless communication system.

  7. Mission creep or responding to wider security needs? The evolving role of mine action organisations in Armed Violence Reduction

    Directory of Open Access Journals (Sweden)

    Sharmala Naidoo

    2013-04-01

    Full Text Available Since the late 1980s, mine action organisations have focused their efforts on reducing the social, economic and environmental impacts of anti-personnel mines and other explosive remnants of war (ERW through a broad range of activities, including survey, clearance, mine risk education (MRE, victim assistance, stockpile destruction and advocacy. In recent years, an increasing number of mine action organisations are using their mine action technical expertise and their capacities to operate in difficult environments to reduce armed violence and promote public safety. Several organisations now have armed violence reduction (AVR-related policies, programmes and staff in place. Some may argue that this shift towards AVR is a diversion from the core mandate of mine action organisations. But does this represent a loss of focus and thereby ‘mission creep’ on the part of these organisations? This practice note examines the factors underlying the evolving role of mine action organisations, discusses how these new programmes are contributing to the wider domain of AVR and explores whether these new programmes have resulted in a loss of organisational focus.

  8. Equivalent magnetic noise reduction at high frequency range due to polarized direction optimization in Terfenol-D/Pb(Mg1/3Nb2/3)O3-PbTiO3 magnetoelectric laminate sensors

    Science.gov (United States)

    Fang, Cong; Ma, Jiashuai; Yao, Meng; Di, Wenning; Lin, Di; Xu, Haiqing; Wang, Wei; Luo, Haosu

    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(Mg1/3Nb2/3)O3-PbTiO3 (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/Hz1/2 at 30 kHz, which is about 1.7 times lower than the 1.35 pT/Hz1/2 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.

  9. High-frequency ultrasonographic imaging of the endothelium-dependent flow-mediated dilatation (FMD) in a brachial artery: normative ranges in a group of low CV risk subjects of different ages.

    Science.gov (United States)

    Ryliskyte, Ligita; Ghiadoni, Lorenzo; Plantinga, Yvonne; Janaviciene, Silvija; Petrulioniene, Zaneta; Laucevicius, Aleksandras; Gintautas, Jonas

    2004-01-01

    High-frequency ultrasonographic imaging of flow-mediated dilatation (FMD) in a brachial artery, as non-invasive technique, was used for the clinical evaluation of endothelial function (EF) in 115 subjects (ages 44.19+/-12.23 (26 to 83) free of coronary heart disease or its equivalents. Our aim was to study the normative ranges for FMD in subjects of different age groups with low cardiovascular risk factors. The mean FMD was 8.23+/-4.51% (0 to 20.9). Multivariate analysis revealed that there were only two independent predictors of FMD: resting vessel diameter (r = -0.45, pFMD = 25.5-0.17 x age-2.6 x resting vessel diameter. Our study demonstrates that FMD in low cardiovascular risk patients inversely correlates with age as well as brachial artery diameter. Normative ranges of FMD could be predicted for different age groups. In addition to conventional methods for the assessment of cardiovascular risk by using a population-based approach (score indexes such as SCORE, FRAMINGH, PROCAM), high-frequency ultrasonographic imaging of flow-mediated dilatation (FMD) in the brachial artery is now becoming an accepted method for the assessment of an individual patient's cardiovascular risk. Although preliminary guidelines have been published, this technique has interpretive limitations. In a study that was published earlier, the authors estimated diameter-related normal ranges of FMD. Several articles reported cut points between control and diseased groups. Data about the impact of age on FMD are also available in the literature. However, this is the first attempt to classify normal values into groups according to age and diameter.

  10. How will a life course framework be used to tackle wider social determinants of health?

    Science.gov (United States)

    Nicolau, Belinda; Marcenes, Wagner

    2012-10-01

    The life course framework, proposed by Kuh and Schlomo in 1997, offers policy makers the means to understand the interaction between nature and nurture. This conceptual model illustrates how an individual's biological resources are influenced by their genetic endowment, their prenatal and postnatal development and their social and physical environment, both in early life and throughout the life course. Health is conceptualized as a dynamic process connecting biological and social elements that are affected by previous experiences and by present circumstances. Therefore, exposure at different stages of people's lives can either enhance or deplete the individual's health resources. Indeed, life course processes are of many kinds, including parent-child relationships, levels of social deprivation, the acquisition of emotional and behavioural assets in adolescence and the long-term effects of occupational hazards and work stress. The long-term effects of nature and nurture combine to influence disease outcomes. It is only in the last decade that theories, methods and new data have begun to be amalgamated, allowing us to further our understanding of health over the life course in ways that may eventually lead to more effective health policies and better health care. This article discusses life course concepts and how this framework can enlighten our understanding of wider social determinants of health, and provides a few examples of potential interventions to tackle their impact on health. © 2012 John Wiley & Sons A/S.

  11. 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.

  12. The specific absorption rate of tissues in rats exposed to electromagnetic plane waves in the frequency range of 0.05-5 GHz and SARwb in free-moving rats.

    Science.gov (United States)

    Chen, Bingxin; Wang, Jiamin; Qi, Hongxin; Zhang, Jie; Chen, Shude; Wang, Xianghui

    2017-03-01

    As electromagnetic exposure experiments can only be performed on small animals, usually rats, research on the characteristics of specific absorption rate (SAR) distribution in the rat has received increasing interest. A series of calculations, which simulated the SAR in a male rat anatomical model exposed to electromagnetic plane waves ranging from 0.05 to 5 GHz with different incidence and polarization, were conducted. The whole-body-averaged SAR (SARwb) and the tissue-averaged SAR (SARavg) in 20 major tissues were determined. Results revealed that incidence has great impact on SAR in the rat at higher frequencies owing to the skin effect and the effect on SARavg in tissues is much more apparent than that on SARwb; while polarization plays an important role under lower frequencies. Not only the incidence, but also the polarization in the rat keeps changing when the rat is in free movement. Thus, this article discussed a convenient way to obtain relatively accurate SARwb in a free-moving rat.

  13. Proposal and verification numerical simulation for a microwave forward scattering technique at upper hybrid resonance for the measurement of electron gyroscale density fluctuations in the electron cyclotron frequency range in magnetized plasmas

    Science.gov (United States)

    Kawamori, E.; Igami, H.

    2017-11-01

    A diagnostic technique for detecting the wave numbers of electron density fluctuations at electron gyro-scales in an electron cyclotron frequency range is proposed, and the validity of the idea is checked by means of a particle-in-cell (PIC) numerical simulation. The technique is a modified version of the scattering technique invented by Novik et al. [Plasma Phys. Controlled Fusion 36, 357-381 (1994)] and Gusakov et al., [Plasma Phys. Controlled Fusion 41, 899-912 (1999)]. The novel method adopts forward scattering of injected extraordinary probe waves at the upper hybrid resonance layer instead of the backward-scattering adopted by the original method, enabling the measurement of the wave-numbers of the fine scale density fluctuations in the electron-cyclotron frequency band by means of phase measurement of the scattered waves. The verification numerical simulation with the PIC method shows that the technique has a potential to be applicable to the detection of electron gyro-scale fluctuations in laboratory plasmas if the upper-hybrid resonance layer is accessible to the probe wave. The technique is a suitable means to detect electron Bernstein waves excited via linear mode conversion from electromagnetic waves in torus plasma experiments. Through the numerical simulations, some problems that remain to be resolved are revealed, which include the influence of nonlinear processes such as the parametric decay instability of the probe wave in the scattering process, and so on.

  14. 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.

  15. Ambient noise techniques for better understanding of seismic hazard in the wider Vienna Basin region

    Science.gov (United States)

    Schippkus, Sven; Zigone, Dimitri; Bokelmann, Götz; AlpArray Working Group

    2017-04-01

    The Vienna Basin is one of the seismically most active regions in Austria. Because of population density and sensitive infrastructure, seismic hazard assessment in this area is of critical importance. Recently, it has become apparent that ambient noise techniques can be applied to provide additional information for seismic hazard studies. This contribution can be either a) indirect by providing detailed 3D tomographic images of the underground, which can be used in further studies, in areas with high seismological station density or b) more direct by predicting ground motions resulting from scenario earthquakes directly from ambient noise. While both techniques are based on the retrieval of the inter-station Green's function from ambient noise interferometry, they are utilizing different features of the Green's function. For calculating tomographic images of the underground, phase information is needed to extract surface wave dispersion curves. Ground motion prediction, however, relies heavily on the extracted amplitude information. Commonly applied ambient noise processing techniques, e.g. pre-whitening, alter amplitudes non-linearly in exchange for more stable phase measurements. Therefore, depending on the study goal, different processing strategies have to be applied. Here, we present a case study for each. To construct the tomographic image of the wider Vienna Basin region (a), we used continuous seismic records from 65 seismological stations in the region, evenly covering the region with an inter-station distance of 40 km. For this, we utilized Love and Rayleigh wave phase and group velocity dispersion curves extracted from ambient noise cross correlations. To demonstrate the applicability of ground motion prediction using ambient noise (b), we use 2 months of continuous data from a temporary station, installed near the site of the ML 4.2 Alland earthquake on April 25th 2016 to retroactively reproduce the long-period earthquake seismograms using ambient noise

  16. Visions, beliefs, and transformation: exploring cross-sector and transboundary dynamics in the wider Mekong region

    Directory of Open Access Journals (Sweden)

    Alex Smajgl

    2015-06-01

    Full Text Available Policy and investment decisions in highly connected, developing regions can have implications that extend beyond their initial objectives of national development and poverty reduction. Local level decisions that aim to promote trajectories toward desirable futures are often transformative, unexpectedly altering factors that are determined at higher regional levels. The converse also applies. The ability to realize desirable local futures diminishes if decision-making processes are not coordinated with other influential governance and decision levels. Providing effective support across multiple levels of decision making in a connected, transformative environment requires (a identification and articulation of desired outcomes at the relevant levels of decision making, (b improved understanding of complex cross-scale interactions that link to potentially transforming decisions, and (c learning among decision makers and decision influencers. Research implemented through multiple participatory modalities can facilitate such relevant system learning to contribute to sustainable adaptation pathways. We test application of a systematic policy engagement framework, the Challenge and Reconstruct Learning or ChaRL framework, on a set of interdependent development decisions in the Mekong region. The analysis presented here is focused on the implementations of the ChaRL process in the Nam Ngum River Basin, Lao People's Democratic Republic and the Tonle Sap Lake and environs, Cambodia to exemplify what cross-scale and cross-sectoral insights were generated to inform decision-making processes in the wider Mekong region. The participatory process described aligns the facilitated development of scenarios articulating shared future visions at local and regional levels with agent-based simulations and facilitates learning by contrasting desired outcomes with likely, potentially maladaptive outcomes.

  17. Role of the anesthesiologist in the wider governance of healthcare and health economics.

    Science.gov (United States)

    Martin, Janet; Cheng, Davy

    2013-09-01

    Healthcare resources will always be limited, and as a result, difficult decisions must be made about how to allocate limited resources across unlimited demands in order to maximize health gains per resource expended. Governments and hospitals now in severe financial deficits recognize that reengagement of physicians is central to their ability to contain the runaway healthcare costs. Health economic analysis provides tools and techniques to assess which investments in healthcare provide good value for money vs which options should be forgone. Robust decision-making in healthcare requires objective consideration of evidence in order to balance clinical and economic benefits vs risks. Surveys of the literature reveal very few economic analyses related to anesthesia and perioperative medicine despite increasing recognition of the need. Now is an opportune time for anesthesiologists to become familiar with the tools and methodologies of health economics in order to facilitate and lead robust decision-making in quality-based procedures. For most technologies used in anesthesia and perioperative medicine, the responsibility to determine cost-effectiveness falls to those tasked with the governance and stewardship of limited resources for unlimited demands using best evidence plus economics at the local, regional, and national levels. Applicable cost-effectiveness, cost-utility, and cost-benefits in health economics are reviewed in this article with clinical examples in anesthesia. Anesthesiologists can make a difference in the wider governance of healthcare and health economics if we advance our knowledge and skills beyond the technical to address the "other" dimensions of decision-making--most notably, the economic aspects in a value-based healthcare system.

  18. FREQUENCY-DEPENDENT DISPERSION MEASURES AND IMPLICATIONS FOR PULSAR TIMING

    Energy Technology Data Exchange (ETDEWEB)

    Cordes, J. M. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Shannon, R. M. [CSIRO Astronomy and Space Science, Box 76, Epping, NSW 1710 (Australia); Stinebring, D. R., E-mail: cordes@astro.cornell.edu, E-mail: ryan.shannon@csiro.au, E-mail: dan.stinebring@oberlin.edu [Department of Physics and Astronomy, Oberlin College, Oberlin, OH 44074 (United States)

    2016-01-20

    The dispersion measure (DM), the column density of free electrons to a pulsar, is shown to be frequency dependent because of multipath scattering from small-scale electron-density fluctuations. DMs vary between propagation paths whose transverse extent varies strongly with frequency, yielding arrival times that deviate from the high-frequency scaling expected for a cold, uniform, unmagnetized plasma (1/frequency{sup 2}). Scaling laws for thin phase screens are verified with simulations; extended media are also analyzed. The rms DM difference across an octave band near 1.5 GHz is ∼ 4 × 10{sup −5} pc cm{sup −3} for pulsars at ∼1 kpc distance. The corresponding arrival-time variations are a few to hundreds of nanoseconds for DM ≲ 30 pc cm{sup −3} but increase rapidly to microseconds or more for larger DMs and wider frequency ranges. Chromatic DMs introduce correlated noise into timing residuals with a power spectrum of “low pass” form. The correlation time is roughly the geometric mean of the refraction times for the highest and lowest radio frequencies used, ranging from days to years, depending on the pulsar. We discuss implications for methodologies that use large frequency separations or wide bandwidth receivers for timing measurements. Chromatic DMs are partially mitigable by including an additional chromatic term in arrival time models. Without mitigation, an additional term in the noise model for pulsar timing is implied. In combination with measurement errors from radiometer noise, an arbitrarily large increase in total frequency range (or bandwidth) will yield diminishing benefits and may be detrimental to overall timing precision.

  19. Capability Database of Injection Molding Process— Requirements Study for Wider Suitability and Higher Accuracy

    DEFF Research Database (Denmark)

    Boorla, Srinivasa Murthy; Eifler, Tobias; Jepsen, Jens Dines O.

    2017-01-01

    for an improved applicability of corresponding database solutions in an industrial context. A survey of database users at all phases of product value chain in the plastic industry revealed that 59% of the participating companies use their own, internally created databases, although reported to be not fully...... adequate in most cases. Essential influences are the suitability of the provided data, defined by the content such as material, tolerance types, etc. covered, as well as its accuracy, largely influenced by the updating frequency. Forming a consortium with stakeholders, linking database update to technology...

  20. Final report of key comparison AFRIMETS.AUV.A-K5: primary pressure calibration of LS1P microphones according to IEC 61094-2, over the frequency range 2 Hz to 10 kHz.

    Science.gov (United States)

    Nel, R.; Avison, J.; Harris, P.; Blabla, M.; Hämäläinen, J.

    2017-01-01

    The degrees of equivalence of the AFRIMETS.AUV.A-K5 regional key comparison are reported here as the final report. The scope of the comparison covered the complex pressure sensitivities of two LS1P microphones over the frequency range 2 Hz to 10 kHz in accordance with IEC 61094-2: 2009. Four national metrology institutes from two different regional metrology organisations participated in the comparison. Two LS1P microphones were circulated simultaneously to all the participants in a circular configuration. One of the microphones sensitivity shifted and all results associated with this microphone were subsequently excluded from further analysis and linking. The AFRIMETS.AUV.A-K5 comparison results were linked to the CCAUV.A-K5 comparison results via dual participation in the CCAUV.A-K5 and AFRIMETS.AUV.A-K5 comparisons. The degrees of equivalence, linked to the CCAUV.A-K5 comparison, were calculated for all participants of this comparison. 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 (CIPM MRA).

  1. Assessing the Impact of Regeneration Spending: Lessons from the United Kingdom and the Wider World

    Science.gov (United States)

    Potts, David

    2008-01-01

    The government increased the funding for regional development agencies to 2.3 billion British Pounds in 2007/8, yet hard evidence on the effectiveness of the spending is difficult to find. Techniques for valuing benefits in difficult areas have existed for many years. They range from the hedonic methods and contingent valuation studies of…

  2. Improvement of low-frequency characteristics of piezoelectric speakers based on acoustic diaphragms.

    Science.gov (United States)

    Kim, Hye Jin; Yang, Woo Seok; No, Kwangsoo

    2012-09-01

    The vibrational characteristics of 3 types of the acoustic diaphragms are investigated to enhance the output acoustic performance of the piezoelectric ceramic speaker in a low-frequency range. In other to achieve both a higher output sound pressure level and wider frequency range of the piezoelectric speaker, we have proposed a rubber/resin bi-layer acoustic diaphragm. The theoretical square-root dependence of the fundamental resonant frequency on the thickness and Young's modulus of the acoustic diaphragm was verified by finite-element analysis simulation and laser scanning vibrometer measurement. The simulated resonant frequencies for each diaphragm correspond well to the measured results. From the simulated and measured resonant frequency results, it is found that the fundamental resonant frequency of the piezoelectric ceramic speaker can be designed by adjusting the thickness ratio of the rubber/resin bi-layer acoustic diaphragm. Compared with a commercial piezoelectric speaker, the fabricated piezoelectric ceramic speaker with the rubber/resin bi-layer diaphragm has at least 10 dB higher sound pressures in the low-frequency range of less than 1 kHz.

  3. 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.

  4. Electrical properties of the electroceramic composite in the microwave frequency range: Pb(Fe0.5Nb0.5)O3 (PFN)-Cr0.75Fe1.25O3 (CRFO)

    Science.gov (United States)

    Santos, M. R. P.; Freire, F. N. A.; Sohn, R. S. T. M.; Almeida, J. S.; Sancho, E. O.; Costa, A. D. S. B.; Medeiros, A. M. L.; Sombra, A. S. B.

    2008-12-01

    In this paper, a new electroceramic composite [Pb(Fe0.5Nb0.5) O3 (PFN)]Z [Cr0.75Fe1.25O3 (CRFO)]100-Z (Z = 0, 10) is investigated in the microwave (MW) frequency range. The dielectric permittivity and loss in the region of 4-8 GHz (G and H MW bands) were studied. The performance of cylindrical resonator antennas based on CRFO100 and on PFN10 was examined. The experimental and theoretical results of the dielectric resonator antenna (DRA) such as return loss, bandwidth, input impedance and radiation patterns are in good agreement for both composites: PFN10 (10% PFN + 90% CRFO) and CRFO100 (100% CRFO). A numerical validation was made considering an air gap between the dielectric resonator and the metallic conductors. The PFN10 matrix composite PFN10 (10% PFN + 90% CRFO) presents the highest dielectric permittivity (9.9 at 4.44 GHz) and the lowest bandwidth (9.9%). The CRFO100 phase (100% CRFO) presents a dielectric permittivity of 8.35 at 4.67 GHz and a bandwidth of 11.8%. The Hakki-Coleman procedure was also used in this study. The dielectric permittivity of 8.35 (tan δ = 1 × 10-3) at 7.94 GHz was obtained for CRFO100. The PFN10 presents a dielectric permittivity of 10.17 (tan δ = 4.9 × 10-3) at 7.05 GHz. These measurements confirm the possible use of such material for small DRAs.

  5. Art history and its dialogue with the wider public: promotion and raising the awareness of cultural heritage

    Directory of Open Access Journals (Sweden)

    Marjana Dolšina

    2013-06-01

    Full Text Available The paper is based on the results of the project All This Painting hasn’t Gone to Waste, 2011, which deals with early 16th century sacral wall paintings in southern Slovenia. It tries to resolve some dilemmas in communication with the wider public and presents main objectives in regard to awareness-rising and promotion of art heritage, for example encouragement of institutions and individual experts for more intensive study and/or conservation-restoration work.

  6. The longevity of national identity and national pride: Evidence from wider Europe

    Directory of Open Access Journals (Sweden)

    Valentina Dimitrova-Grajzl

    2016-06-01

    Full Text Available National pride predicts a wide range of politico-economic outcomes, yet what makes individuals proud of their nation is not completely understood. We propose and test a theory that an important but thus far unexplored determinant of contemporary national pride is the longevity of national identity. To measure the longevity of national identity, we construct an index based on responses from an original expert survey designed to trace the emergence of national identity across the polities of Europe and the former Soviet Union. We find that our National Identity Longevity Index is statistically significantly positively associated with the extent of national pride. The implied effect is robust and noteworthy in magnitude. Our results suggest that contemporary national pride inter alia reflects deep, historically rooted societal conventions which take time to emerge.

  7. Wider stall space affects behavior, lesion scores, and productivity of gestating sows.

    Science.gov (United States)

    Salak-Johnson, J L; DeDecker, A E; Levitin, H A; McGarry, B M

    2015-10-01

    Limited space allowance within the standard gestation stall is an important welfare concern because it restricts the ability of the sow to make postural adjustments and hinders her ability to perform natural behaviors. Therefore, we evaluated the impacts of increasing stall space and/or providing sows the freedom to access a small pen area on sow well-being using multiple welfare metrics. A total of 96 primi- and multiparous crossbred sows were randomly assigned in groups of 4 sows/treatment across 8 replicates to 1 of 3 stall treatments (TRT): standard stall (CTL; dimensions: 61 by 216 cm), width-adjustable stall (flex stall [FLX]; dimensions: adjustable width of 56 to 79 cm by 216 cm), or an individual walk-in/lock-in stall with access to a small communal open-pen area at the rear of the stall (free-access stall [FAS]; dimensions: 69 by 226 cm). Lesion scores, behavior, and immune and productivity traits were measured at various gestational days throughout the study. Total lesion scores were greatest for sows in FAS and least for sows in FLX ( Regardless of parity, sows in FLX had the least severe scores ( < 0.0001). As pregnancy progressed, lesion scores increased among sows in CTL ( < 0.05). Sow BW and backfat (BF) were greater for sows in FLX and FAS ( < 0.05), and BCS and BF were greater for parity 1 and 2 sows in FAS than the same parity sows in CTL (TRT × parity, < 0.05). Duration and frequency of some postural behaviors and sham chew behavior were affected by TRT ( < 0.05) and time of day (TRT × day, < 0.05). These data indicate that adequate stall space, especially late in gestation, may improve the well-being of higher-parity and heavier-bodied gestating sows as assessed by changes in postural behaviors, lesion severity scores, and other sow traits. Moreover, compromised welfare measures found among sows in various stall environments may be partly attributed to the specific constraints of each stall system such as restricted stall space in CTL

  8. High-frequency phosphorus and nitrate measurements for improved statutory water quality monitoring and management

    Science.gov (United States)

    Bieroza, Magdalena

    2017-04-01

    High-frequency nutrient (phosphorus and nitrogen) monitoring using wet-chemistry analysers and optical sensors has revolutionised the collection of biogeochemical data from streams, rivers and lakes. Matching the nutrient measurement time with timescales of hydrological responses has revealed biogeochemical patterns and nutrient hydrological responses not observed previously. Capturing a wider range of nutrient concentrations compared to traditional coarse resolution sampling enables more accurate estimation of mean concentrations and loads and thus improved water body classification. However, to date the scientific insights from the high-frequency nutrient monitoring studies have not been translated into policy and operational responses. The pertinent question is where and how often to measure nutrients to satisfy statutory monitoring requirements for the Water Framework Directive and the Nitrates Directive. Therefore this paper discusses how the reduced data uncertainty and improved process understanding obtained with the high-frequency measurements can improve statutory nutrient monitoring, using case studies from England and Sweden.

  9. Disruption to control network function correlates with altered dynamic connectivity in the wider autism spectrum

    Directory of Open Access Journals (Sweden)

    N. de Lacy

    2017-01-01

    Full Text Available Autism is a common developmental condition with a wide, variable range of co-occurring neuropsychiatric symptoms. Contrasting with most extant studies, we explored whole-brain functional organization at multiple levels simultaneously in a large subject group reflecting autism's clinical diversity, and present the first network-based analysis of transient brain states, or dynamic connectivity, in autism. Disruption to inter-network and inter-system connectivity, rather than within individual networks, predominated. We identified coupling disruption in the anterior-posterior default mode axis, and among specific control networks specialized for task start cues and the maintenance of domain-independent task positive status, specifically between the right fronto-parietal and cingulo-opercular networks and default mode network subsystems. These appear to propagate downstream in autism, with significantly dampened subject oscillations between brain states, and dynamic connectivity configuration differences. Our account proposes specific motifs that may provide candidates for neuroimaging biomarkers within heterogeneous clinical populations in this diverse condition.

  10. Looking Wider and Further: The Evolution of Galaxies Inside Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuanyuan [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-01-01

    Galaxy clusters are rare objects in the universe, but on-going wide field optical surveys are identifying many thousands of them to redshift 1.0 and beyond. Using early data from the Dark Energy Survey (DES) and publicly released data from the Sloan Digital Sky Survey (SDSS), this dissertation explores the evolution of cluster galaxies in the redshift range from 0 to 1.0. As it is common for deep wide field sky surveys like DES to struggle with galaxy detection efficiency at cluster core, the first component of this dissertation describes an efficient package that helps resolving the issue. The second part focuses on the formation of cluster galaxies. The study quantifies the growth of cluster bright central galaxies (BCGs), and argues for the importance of merging and intra-cluster light production during BCG evolution. An analysis of cluster red sequence galaxy luminosity function is also performed, demonstrating that the abundance of these galaxies is mildly dependent on cluster mass and redshift. The last component of the dissertation characterizes the properties of galaxy filaments to help understanding cluster environments

  11. The fish and fisheries of Jones Bank and the wider Celtic Sea

    Science.gov (United States)

    Martinez, I.; Ellis, J. R.; Scott, B.; Tidd, A.

    2013-10-01

    The Celtic Sea is a diverse fishing ground that supports important commercial fisheries for a range of demersal fish, large and small-bodied pelagic fish and a variety of cephalopods and other shellfish. A regional overview of the main commercial fish stocks of the Celtic Sea and of the fish that occur in the vicinity of Jones Bank are provided through analyses of landings data from English and Welsh vessels, and from scientific trawl surveys. Dedicated smaller scale sampling via trawl surveys combined with baited cameras on and around the Jones Bank were also analysed to investigate the importance of sandbank habitats with attention paid to the differences in the species occurring on the top of the bank in comparison to adjacent off-bank habitats. Official landing statistics for UK (English and Welsh) vessels indicated that the predominant commercial demersal species in ICES Divisions VIIg,h (in terms of quantities landed) were anglerfish, megrim, pollack and skates (Rajidae). There were, however, regional differences in the distribution of fish and fisheries, and the area surrounding Jones Bank (ICES Rectangles 28E1 and 28E2) supports fisheries for megrim, anglerfish, skates, hake, ling and turbot, with otter trawl, gillnet and beam trawl the main gears used. Recent survey data collected with GOV (Grande Ouverture Verticale) trawl from the Celtic Sea (ICES Divisions VIIe-h, 2007-2010) were used to highlight the broad scale distribution of the main fish assemblages in the Celtic Sea. Analyses of the fish and cephalopod catches from these surveys indicated that there were four broad assemblages in the area, including (i) a region around the Cornwall (which will also be partly influenced by the necessity to use rockhopper ground gear on these rough grounds), (ii) the shallower regions of the north-western Celtic Sea (including parts of the Bristol Channel), (iii) the deeper parts of the outer shelf and (iv) the central Celtic Sea. These data also provided

  12. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  13. 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...... in the shape of the METFs, thought to be affected by the helicotrema impedance. Preliminary analysis indicates that individual differences in the METFs might underlay the observed individual differences in frequency selectivity. Main effects predicted by the calculations are a pronounced flattening off...

  14. High-dynamic-range and high-capacity RF and microwave fiber optic links

    Science.gov (United States)

    Weiss, Frank

    2013-05-01

    Novel fiber optic transmitter control methodologies, high optical power and low RIN source lasers, high performance photodiodes and DWDM laser capability provide high dynamic range and high capacity transport for a wide range of sensing and communications applications. Measured component and system level test data demonstrates these performance improvements. Higher spur free dynamic range in excess of 110 dB·Hz2/3 over broad range of K-band frequencies is demonstrated, increasing the practical use of fiber as a transport method for high sensitivity applications. Multichannel DWDM operation provides simplified capacity expansion without compromising system performance, allowing arrayed photonic systems to be deployed. System characterization for a wide range of optical wavelengths and RF frequencies is provided to demonstrate these levels of performance in practical applications. Photonic component cost reductions combined with compact packaging further increase the ability of high performance fiber optic transport to address a wider range of applications, as the size, weight and performance barriers are eliminated. This paper provides a summary of the current state of the art of commercially available photonic components for high performance externally modulated analog optical links from a practical perspective.

  15. Method for enhancing the resolving power of ion mobility separations over a limited mobility range

    Science.gov (United States)

    Shvartsburg, Alexandre A; Tang, Keqi; Smith, Richard D

    2014-09-23

    A method for raising the resolving power, specificity, and peak capacity of conventional ion mobility spectrometry is disclosed. Ions are separated in a dynamic electric field comprising an oscillatory field wave and opposing static field, or at least two counter propagating waves with different parameters (amplitude, profile, frequency, or speed). As the functional dependencies of mean drift velocity on the ion mobility in a wave and static field or in unequal waves differ, only single species is equilibrated while others drift in either direction and are mobility-separated. An ion mobility spectrum over a limited range is then acquired by measuring ion drift times through a fixed distance inside the gas-filled enclosure. The resolving power in the vicinity of equilibrium mobility substantially exceeds that for known traveling-wave or drift-tube IMS separations, with spectra over wider ranges obtainable by stitching multiple segments. The approach also enables low-cutoff, high-cutoff, and bandpass ion mobility filters.

  16. A wider pelvis does not increase locomotor cost in humans, with implications for the evolution of childbirth.

    Directory of Open Access Journals (Sweden)

    Anna G Warrener

    Full Text Available The shape of the human female pelvis is thought to reflect an evolutionary trade-off between two competing demands: a pelvis wide enough to permit the birth of large-brained infants, and narrow enough for efficient bipedal locomotion. This trade-off, known as the obstetrical dilemma, is invoked to explain the relative difficulty of human childbirth and differences in locomotor performance between men and women. The basis for the obstetrical dilemma is a standard static biomechanical model that predicts wider pelves in females increase the metabolic cost of locomotion by decreasing the effective mechanical advantage of the hip abductor muscles for pelvic stabilization during the single-leg support phase of walking and running, requiring these muscles to produce more force. Here we experimentally test this model against a more accurate dynamic model of hip abductor mechanics in men and women. The results show that pelvic width does not predict hip abductor mechanics or locomotor cost in either women or men, and that women and men are equally efficient at both walking and running. Since a wider birth canal does not increase a woman's locomotor cost, and because selection for successful birthing must be strong, other factors affecting maternal pelvic and fetal size should be investigated in order to help explain the prevalence of birth complications caused by a neonate too large to fit through the birth canal.

  17. A Wider Pelvis Does Not Increase Locomotor Cost in Humans, with Implications for the Evolution of Childbirth

    Science.gov (United States)

    Warrener, Anna G.; Lewton, Kristi L.; Pontzer, Herman; Lieberman, Daniel E.

    2015-01-01

    The shape of the human female pelvis is thought to reflect an evolutionary trade-off between two competing demands: a pelvis wide enough to permit the birth of large-brained infants, and narrow enough for efficient bipedal locomotion. This trade-off, known as the obstetrical dilemma, is invoked to explain the relative difficulty of human childbirth and differences in locomotor performance between men and women. The basis for the obstetrical dilemma is a standard static biomechanical model that predicts wider pelves in females increase the metabolic cost of locomotion by decreasing the effective mechanical advantage of the hip abductor muscles for pelvic stabilization during the single-leg support phase of walking and running, requiring these muscles to produce more force. Here we experimentally test this model against a more accurate dynamic model of hip abductor mechanics in men and women. The results show that pelvic width does not predict hip abductor mechanics or locomotor cost in either women or men, and that women and men are equally efficient at both walking and running. Since a wider birth canal does not increase a woman’s locomotor cost, and because selection for successful birthing must be strong, other factors affecting maternal pelvic and fetal size should be investigated in order to help explain the prevalence of birth complications caused by a neonate too large to fit through the birth canal. PMID:25760381

  18. The Arabic culture of Jordan and its impacts on a wider Jordanian adoption of business continuity management.

    Science.gov (United States)

    Sawalha, Ihab H; Meaton, Julia

    2012-01-01

    Culture is important to individuals and societies, as well as organisations. Failing to address cultural aspects will hinder the wider adoption and development of business continuity management (BCM) and will subsequently increase the vulnerabilities of organisations to crises, disasters and business interruptions. Three main issues are discussed in this paper. The first is the background to culture and the characteristics of the Jordanian culture. Secondly, the influence of the Arab culture on the wider adoption and development of BCM in Jordan is considered. Thirdly, the paper looks at potential factors that underpin the role of culture in the BCM process in Jordan. These issues are significant, as they represent the characteristics and influence of the Arab culture. This paper contributes to the understanding of the significance of culture in the adoption and development of BCM for organisations operating in Jordan and in the Arab world more generally. It also highlights current cultural changes and trends taking place in the Arab world in a time of huge political instability in the Middle East and Arab countries.

  19. 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...

  20. Towards a wider dialogue

    CERN Multimedia

    2012-01-01

    This week, I had the rewarding experience of taking part in a Wilton Park meeting examining three very different world-views: science, philosophy and theology. Wilton Park describes itself as a forum for analysing and advancing the agenda on global policy challenges, and over the years it has developed an enviable reputation for delivering authoritative reports drawn from bringing international experts together under the same roof for two days to discuss issues of topical relevance.   Participation is by invitation and there are no observers: everyone is there because they have something to bring to the discussion. Wilton Park reports always have their finger on the zeitgeist, appropriately, perhaps, for an institution born of Winston Churchill’s vision for reconciliation and dialogue in post-war Europe. When I learned that Wilton Park was running a series of meetings examining the role of religion in modern society, and that it was looking at the possibility of holding an event in...

  1. Wider than the Sky

    Science.gov (United States)

    Barbieri, Richard

    2015-01-01

    More has been learned about the human brain in the past few decades than in the whole prior history of humanity. In this article Richard Barbieri considers learning and the brain from a few different perspectives. He begins by examining the practice of neuroscience itself and what was understood about the brain before neuroscience. This leads to a…

  2. Broadband frequency conversion

    DEFF Research Database (Denmark)

    Sanders, Nicolai; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter

    We present a simple, passive and static setup for broadband frequency conversion. By using simple optical components like lenses, mirrors and gratings, we obtain the spectral angular dispersion to match the second harmonic generation phasematching angles in a nonlinear BiBO crystal. We are able...... to frequency double a single-frequency diode laser, tunable in the 1020-1090 nm range, with almost equal efficiency for all wavelengths. In the experimental setup, the width of the phasematch was increased with a factor of 50. The method can easily be extended to other wavelength ranges and nonlinear crystals...

  3. Theoretical and experimental study of two-frequency solid-state lasers in the GHz to THz ranges. Opto-microwave applications waves; Etude theorique et experimentale des lasers solides bi-frequences dans les domaines GHz a THz, en regime continu ou impulsionnel. Applications opto-microondes

    Energy Technology Data Exchange (ETDEWEB)

    Lai, N.D.

    2003-07-15

    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{sup -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 {mu}m 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

  4. From medieval Dar al-Islam to contemporary Malta: raḥl toponymy in a wider western Mediterranean context

    Directory of Open Access Journals (Sweden)

    Charles Dalli

    2016-11-01

    Full Text Available The diffusion of raḥl placenames in Andalus and the islands of Majorca, Sicily and Malta in the High Middle Ages has long been noted, studied, and served as the subject of scholarly debate. With the transition of these western Mediterranean lands from Islam to Christianity in the wake of the Iberian Reconquista and the establishment of the Norman Kingdom of Sicily, the raḥl did not disappear, but rather became a staple of Christian colonization records in Majorca and Sicily. The same cross-cultural process extends to the example of Malta, where the survival of an Arabic dialect arguably assisted the retention of the raḥl as a living model for placenaming. The paper argues that the raḥl toponym, originally representing a small-scale and individual unit, lent itself particularly well in the insular contexts of the medieval Christian expansion, fitting flexibly in the wider framework of cultural hybridization.

  5. 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

  6. 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

  7. Operational and safety impacts of restriping inside lanes of urban multilane curbed roadways to 11 feet or less to create wider outside curb lanes for bicyclists.

    Science.gov (United States)

    2011-09-30

    This study analyzes the influence of several site characteristics on the operational behavior of motorists when passing bicyclists on wider outside through lanes. More than 2000 videotaped passing events were analyzed. Several measures of effectivene...

  8. Nonlinear Frequency Compression

    Science.gov (United States)

    Scollie, Susan; Glista, Danielle; Seelisch, Andreas

    2013-01-01

    Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality. PMID:23539261

  9. Frequency selective terahertz retroreflectors

    Science.gov (United States)

    Williams, Richard James

    The use of novel optical structures operating at terahertz frequencies in industrial and military applications continues to grow. Some of these novel structures include gratings, frequency selective surfaces, metamaterials and metasurfaces, and retroreflectors. A retroreflector is a device that exhibits enhanced backscatter by concentrating the reflected wave in the direction of the source. Retroreflectors have applications in a variety of diverse fields such as aviation, radar systems, antenna technology, communications, navigation, passive identification, and metrology due to their large acceptance angles and frequency bandwidth. This thesis describes the design, fabrication, and characterization of a retroreflector designed for terahertz frequencies and the incorporation of a frequency selective surface in order to endow the retroreflector with narrow-band frequency performance. The radar cross section of several spherical lens reflectors operating at terahertz frequencies was investigated. Spherical lens reflectors with diameters ranging from 2 mm to 8 mm were fabricated from fused silica ball lenses and their radar cross section was measured at 100 GHz, 160 GHz, and 350 GHz. Crossed-dipole frequency selective surfaces exhibiting band-pass characteristics at 350 GHz fabricated from 12 um-thick Nickel screens were applied to the apertures of the spherical lens reflectors. The radar cross section of the frequency selective retroreflectors was measured at 160 GHz and 350 GHz to demonstrate proof-of-concept of narrow-band terahertz performance.

  10. 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

    Science.gov (United States)

    2006-02-06

    and a reverberation time of approximately 5 ms. 3. In the marina facing FAU SeaTech, keeping source and receiver static at 20 to 50 m range [9...Both source and receiver can move. In each case, the ambient noise level, bathymetry, channel impulse response, reverberation time , Doppler shift and...in the marina and the turning basin confirmed this statement. Overall, the reverberation time tends to remain within 1 ms, and very occasionally

  11. Marine spatial planning (MSP: A first step to ecosystem-based management (EBM in the Wider Caribbean

    Directory of Open Access Journals (Sweden)

    John C Ogden

    2010-10-01

    Full Text Available The rapid decline of coastal ecosystems of the Wider Caribbean is entering its fifth decade. Some of the best science documenting this decline and its causes has been done by the laboratories of the Association of Marine Laboratories of the Caribbean (AMLC. Alarmed at the trends, Caribbean conservation pioneers established marine protected areas (MPAs which spread throughout the region. Unfortunately, many have little or no protection and are now known to be too small to be effective in sustaining coastal ecosystems. Marine spatial planning (MSP holds much promise to encompass the large geographic scales of the ecological processes and human impacts that influence coastal ecosystems and adjacent lands. The AMLC, through the scientific expertise and the national political connections of its member institutions, is well-positioned to help implement a pilot project. MSP a first step in ecosystem-based management and has had considerable success elsewhere. It holds our best chance of sustaining human use and conserving the coral reefs and associated ecosystems. Rev. Biol. Trop. 58 (Suppl. 3: 71-79. Epub 2010 October 01.

  12. Marine spatial planning (MSP): a first step to ecosystem-based management (EBM) in the Wider Caribbean.

    Science.gov (United States)

    Ogden, John C

    2010-10-01

    The rapid decline of coastal ecosystems of the Wider Caribbean is entering its fifth decade. Some of the best science documenting this decline and its causes has been done by the laboratories of the Association of Marine Laboratories of the Caribbean (AMLC). Alarmed at the trends, Caribbean conservation pioneers established marine protected areas (MPAs) which spread throughout the region. Unfortunately, many have little or no protection and are now known to be too small to be effective in sustaining coastal ecosystems. Marine spatial planning (MSP) holds much promise to encompass the large geographic scales of the ecological processes and human impacts that influence coastal ecosystems and adjacent lands. The AMLC, through the scientific expertise and the national political connections of its member institutions, is well-positioned to help implement a pilot project. MSP a first step in ecosystem-based management and has had considerable success elsewhere. It holds our best chance of sustaining human use and conserving the coral reefs and associated ecosystems.

  13. Habitat monitoring in the wider countryside: a case study on the pursuit of innovation in red deer management.

    Science.gov (United States)

    Maffey, Georgina; Reed, Mark; Irvine, R Justin; van der Wal, René

    2013-10-15

    Policy frameworks for protected areas, such as the EU habitats directive, ensure that environmental monitoring takes place to assess the condition of these sites. However, this monitoring rarely extends to the wider countryside, and there is no obligation for private landowners to detect trends in habitat condition. Using the diffusion of innovations model as an analytical framework we conducted a series of semi-structured interviews to consider the uptake of habitat impact assessment methods throughout a community involved in private land use pursuits in Scotland. It was found that although the community as a whole recognises the benefits of habitat impact assessments there are a number of barriers to their uptake, including the complexity of data gathering and interpretation, and uncertainty around who should be responsible for the conduct of assessments. Analysing the uptake of an innovation at an early stage, rather than retrospectively as is commonly done, highlights the potential for non-adoption and could therefore inform the reinvention of the innovation. In this instance reinvention could lead to more appropriate monitoring methods, which, if taken up, could reduce the need for legislative intervention in situations where both public and private interests need to be considered. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Managing workplace stress in community pharmacy organisations: lessons from a review of the wider stress management and prevention literature.

    Science.gov (United States)

    Jacobs, Sally; Johnson, Sheena; Hassell, Karen

    2017-03-27

    Workplace stress in community pharmacy is increasing internationally due, in part, to pharmacists' expanding roles and escalating workloads. Whilst the business case for preventing and managing workplace stress by employers is strong, there is little evidence for the effectiveness of organisational stress management interventions in community pharmacy settings. To identify and synthesise existing evidence for the effectiveness of organisational solutions to workplace stress from the wider organisational literature which may be adaptable to community pharmacies. A secondary synthesis of existing reviews. Publications were identified through keyword searches of electronic databases and the internet; inclusion and exclusion criteria were applied; data about setting, intervention, method of evaluation, effectiveness and conclusions (including factors for success) were extracted and synthesised. Eighteen reviews of the stress management and prevention literature were identified. A comprehensive list of organisational interventions to prevent or manage workplace stress, ordered by prevalence of evidence of effectiveness, was produced, together with an ordered list of the benefits both to the individual and employing organisation. An evidence-based model of best practice was derived specifying eight factors for success: top management support, context-specific interventions, combined organisational and individual interventions, a participative approach, clearly delineated tasks and responsibilities, buy-in from middle management, change agents as facilitators and change in organisational culture. This literature review provides community pharmacy organisations with evidence from which to develop effective and successful stress management strategies to support pharmacists and pharmacy staff. Well-designed trials of stress management interventions in community pharmacy organisations are still required. © 2017 Royal Pharmaceutical Society.

  15. The relative risk of fatal poisoning by methadone or buprenorphine within the wider population of England and Wales.

    Science.gov (United States)

    Marteau, Dave; McDonald, Rebecca; Patel, Kamlesh

    2015-05-29

    To examine the population-wide overdose risk emerging from the prescription of methadone and buprenorphine for opioid substitution treatment in England and Wales. Retrospective administrative data study. National databases for England and Wales. Drug-related mortality data were drawn from the Office for National Statistics, and prescription data for methadone and buprenorphine were obtained from the National Health Service for the years 2007-2012. During this 6-year period, a total of 2366 methadone-related deaths and 52 buprenorphine-related deaths were registered, corresponding to 17,333,163 methadone and 2,602,374 buprenorphine prescriptions issued. The analysis encompassed poisoning deaths among members of the wider population of England and Wales who consumed, but were not prescribed these medications, in addition to patients prescribed methadone or buprenorphine. Mortality risk: substance-specific overdose rate per 1000 prescriptions issued; relative risk ratio of methadone in relation to buprenorphine. During the years 2007-2012, the pooled overdose death rate was 0.137/1000 prescriptions of methadone, compared to 0.022/1000 prescriptions of buprenorphine (including buprenorphine-naloxone). The analysis generated a relative risk ratio of 6.23 (95% CI 4.79 to 8.10) of methadone in relation to buprenorphine. UK Borders Agency data were taken into consideration and revealed that only negligible amounts of methadone and buprenorphine were seized on entering UK territory between 2007 and 2012, suggesting domestic diversion. Our analysis of the relative safety of buprenorphine and methadone for opioid substitution treatment reveals that buprenorphine is six times safer than methadone with regard to overdose risk among the general population. Clinicians should be aware of the increased risk of prescribing methadone, and tighter regulations are needed to prevent its diversion. Published by the BMJ Publishing Group Limited. For permission to use (where not already

  16. The relative risk of fatal poisoning by methadone or buprenorphine within the wider population of England and Wales

    Science.gov (United States)

    Marteau, Dave

    2015-01-01

    Objective To examine the population-wide overdose risk emerging from the prescription of methadone and buprenorphine for opioid substitution treatment in England and Wales. Design Retrospective administrative data study. Setting National databases for England and Wales. Participants/cases Drug-related mortality data were drawn from the Office for National Statistics, and prescription data for methadone and buprenorphine were obtained from the National Health Service for the years 2007–2012. During this 6-year period, a total of 2366 methadone-related deaths and 52 buprenorphine-related deaths were registered, corresponding to 17 333 163 methadone and 2 602 374 buprenorphine prescriptions issued. The analysis encompassed poisoning deaths among members of the wider population of England and Wales who consumed, but were not prescribed these medications, in addition to patients prescribed methadone or buprenorphine. Main outcome measures Mortality risk: substance-specific overdose rate per 1000 prescriptions issued; relative risk ratio of methadone in relation to buprenorphine. Results During the years 2007–2012, the pooled overdose death rate was 0.137/1000 prescriptions of methadone, compared to 0.022/1000 prescriptions of buprenorphine (including buprenorphine-naloxone). The analysis generated a relative risk ratio of 6.23 (95% CI 4.79 to 8.10) of methadone in relation to buprenorphine. UK Borders Agency data were taken into consideration and revealed that only negligible amounts of methadone and buprenorphine were seized on entering UK territory between 2007 and 2012, suggesting domestic diversion. Conclusions Our analysis of the relative safety of buprenorphine and methadone for opioid substitution treatment reveals that buprenorphine is six times safer than methadone with regard to overdose risk among the general population. Clinicians should be aware of the increased risk of prescribing methadone, and tighter regulations are needed to prevent its

  17. Basin Testing of Wave Energy Converters in Trondheim: Investigation of Mooring Loads and Implications for Wider Research

    Directory of Open Access Journals (Sweden)

    Vladimir Krivtsov

    2014-04-01

    Full Text Available This paper describes the physical model testing of an array of wave energy devices undertaken in the NTNU (Norwegian University of Science and Technology Trondheim basin between 8 and 20 October 2008 funded under the EU Hydralabs III initiative, and provides an analysis of the extreme mooring loads. Tests were completed at 1/20 scale on a single oscillating water column device and on close-packed arrays of three and five devices following calibration of instrumentation and the wave and current test environment. One wave energy converter (WEC was fully instrumented with mooring line load cells, optical motion tracker and accelerometers and tested in regular waves, short- and long-crested irregular waves and current. The wave and current test regimes were measured by six wave probes and a current meter. Arrays of three and five similar WECs, with identical mooring systems, were tested under similar environmental loading with partial monitoring of mooring forces and motions. The majority of loads on the mooring lines appeared to be broadly consistent with both logistic and normal distribution; whilst the right tail appeared to conform to the extreme value distribution. Comparison of the loads at different configurations of WEC arrays suggests that the results are broadly consistent with the hypothesis that the mooring loads should differ. In particular; the results from the tests in short crested seas conditions give an indication that peak loads in a multi WEC array may be considerably higher than in 1-WEC configuration. The test campaign has contributed essential data to the development of Simulink™ and Orcaflex™ models of devices, which include mooring system interactions, and data have also been obtained for inter-tank comparisons, studies of scale effects and validation of mooring system numerical models. It is hoped that this paper will help to draw the attention of a wider scientific community to the dataset freely available from the

  18. Development of postoperative C5 palsy is associated with wider posterior decompressions: an analysis of 41 patients.

    Science.gov (United States)

    Bydon, Mohamad; Macki, Mohamed; Aygun, Nafi; Sciubba, Daniel M; Wolinsky, Jean-Paul; Witham, Timothy F; Gokaslan, Ziya L; Bydon, Ali

    2014-12-01

    C5 palsy is a postoperative complication, characterized by deltoid weakness. The pathogenesis of C5 palsy after laminoforaminotomies in patients with degenerative spinal disease is poorly understood. We hypothesize that the spinal cord fallback is associated with postoperative C5 palsy. We investigate radiographic parameters associated with the development of postoperative C5 palsy. This is a retrospective single-institutional clinical study. The source population was all patients undergoing a C4-C5 posterior laminoforaminotomy plus instrumented fusion for the management of degenerative spinal disease at a single institution over a 7-year period. The study population was 41 patients who had both preoperative and postoperative imaging. The outcome measure was postoperative C5 palsy, defined as transient motor decline of the deltoid function. Of those patients with both preoperative and postoperative radiographic studies, we measured cord position, Cobb angle, width of the C5 foramen, and width of the dura. Nine patients with C5 palsy and 32 patients without C5 palsy fit the inclusion criteria for this study. In comparison with the non-C5 palsy group, the C5 palsy group had a statistically greater widening of the C5 foramen (pC5 palsy in univariate analysis (p=.627). Conversely, widening of the C5 foramen was correlated with greater cord displacement (p=.002), and both of these factors statistically predicted C5 palsy after the multivariate regression analysis. Our findings suggest that wider decompressions at C4-C5 are correlated with greater fallback of the spinal cord, which statistically increases the risk of C5 palsy. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Mosquito (Aedes aegypti) flight tones: Frequency, harmonicity, spherical spreading, and phase relationships

    Science.gov (United States)

    Arthur, Benjamin J.; Emr, Kevin S.; Wyttenbach, Robert A.; Hoy, Ronald R.

    2014-01-01

    Mosquito flight produces a tone as a side effect of wing movement; this tone is also a communication signal that is frequency-modulated during courtship. Recordings of tones produced by tethered flying male and female Aedes aegypti were undertaken using pairs of pressure-gradient microphones above and below, ahead and behind, and to the left and right over a range of distances. Fundamental frequencies were close to those previously reported, although amplitudes were lower. The male fundamental frequency was higher than that of the female and males modulated it over a wider range. Analysis of harmonics shows that the first six partials were nearly always within 1 Hz of integer multiples of the fundamental, even when the fundamental was being modulated. Along the front-back axis, amplitude attenuated as a function of distance raised to the power 2.3. Front and back recordings were out of phase, as were above and below, while left and right were in phase. Recordings from ahead and behind showed quadratic phase coupling, while others did not. Finally, two methods are presented for separating simultaneous flight tones in a single recording and enhancing their frequency resolution. Implications for mosquito behavior are discussed. PMID:25234901

  20. Arbitrary optical frequency synthesis traced to an optical frequency comb

    Science.gov (United States)

    Cai, Zihang; Zhang, Weipeng; Yang, Honglei; Li, Yan; Wei, Haoyun

    2016-11-01

    An arbitrary optical frequency synthesizer with a broad tuning range and high frequency accuracy is presented. The system includes an external cavity diode laser (ECDL) as the output laser, an Erbium-doped optical frequency comb being a frequency reference, and a control module. The optical frequency from the synthesizer can be continuously tuned by the large-scale trans-tooth switch and the fine intra-tooth adjustment. Robust feedback control by regulating the current and PZT voltage enables the ECDL to phase-lock to the Erbium-doped optical frequency comb, therefore to keep stable frequency output. In the meanwhile, the absolute frequency of the synthesizer is determined by the repetition rate, the offset frequency and the beat frequency. All the phase lock loops in the system are traced back to a Rubidium clock. A powerful and friendly software is developed to make the operation convenient by integrating the functions of frequency setting, tuning, tracing, locking and measuring into a LabVIEW interface. The output frequency tuning span and the uncertainty of the system are evaluated as >6 THz and <3 kHz, respectively. The arbitrary optical frequency synthesizer will be a versatile tool in diverse applications, such as synthetic wavelength based absolute distance measurement and frequency-stabilized Cavity Ring-Down Spectroscopy.

  1. A comparison between electric field strengths similarly generated and measured in the open air, in a shielded enclosure and in a large aircraft hangar, over frequency range 10 to 110 MHz

    Science.gov (United States)

    Dew, M.; Harrison, F.

    1980-02-01

    Field strength measurements over 10 to 110 MHz were made using a tracking generator counter, a spectrum analyzer, and a biconal antenna. The dimensions of the shielded enclosure were 6.1 x 3.66 x 3.0 m, and the concrete floored, metal hangar 80 x 40 x 10 m. It was found that in each polarization the hangar performance deviated much less from that in the open air than did the shielded enclosure performance. The latter shows deviations with modulus as great as 38 dB (certical pol) and 26 dB (horizontal pol). For any electric field strength measured in the shielded enclosure (in 10 kHz bandwidth in the range 10 to 110 MHz) the probability that the result would be at least 6 dB different from that similary obtained in the open air was 38% or 43.5% according to polarization and that when similarly measured in the hangar the corresponding probabilities were 0% and 1%. Hangar results were shown to lie much closer to the open air results than do the shielded enclosure results. This is further demonstrated by the rms deviations of the shielded enclosure and hangar readings from those of the open air.

  2. Marine spatial planning (MSP: A first step to ecosystem-based management (EBM in the Wider Caribbean

    Directory of Open Access Journals (Sweden)

    John C Ogden

    2010-10-01

    Full Text Available The rapid decline of coastal ecosystems of the Wider Caribbean is entering its fifth decade. Some of the best science documenting this decline and its causes has been done by the laboratories of the Association of Marine Laboratories of the Caribbean (AMLC. Alarmed at the trends, Caribbean conservation pioneers established marine protected areas (MPAs which spread throughout the region. Unfortunately, many have little or no protection and are now known to be too small to be effective in sustaining coastal ecosystems. Marine spatial planning (MSP holds much promise to encompass the large geographic scales of the ecological processes and human impacts that influence coastal ecosystems and adjacent lands. The AMLC, through the scientific expertise and the national political connections of its member institutions, is well-positioned to help implement a pilot project. MSP a first step in ecosystem-based management and has had considerable success elsewhere. It holds our best chance of sustaining human use and conserving the coral reefs and associated ecosystems. Rev. Biol. Trop. 58 (Suppl. 3: 71-79. Epub 2010 October 01.La rápida disminución de los ecosistemas costeros del Mar Caribe está entrando en su quinta década. Algunos de los mejores aportes científicos que documentan este descenso y sus causas han sido realizados por los laboratorios de la Asociación de Laboratorios Marinos del Caribe (ALMC. Alarmados por las tendencias, los pioneros de la conservación del Caribe establecieron áreas marinas protegidas (MPAs que se extendieron por toda la región. Desafortunadamente, muchas de estas áreas tienen poca o ninguna protección y ahora se conoce que son demasiado pequeñas para ser efectivas en el mantenimiento de los ecosistemas costeros. La planificación espacial marina (MSP es promisoria para englobar las grandes escalas geográficas de los procesos ecológicos y los impactos humanos que influyen en los ecosistemas costeros y las

  3. Asynchronous BCI control using high-frequency SSVEP

    National Research Council Canada - National Science Library

    Diez, Pablo F; Mut, Vicente A; Avila Perona, Enrique M; Laciar Leber, Eric

    2011-01-01

    ...) and high frequency (> 30 Hz). SSVEP-based Brain-Computer Interfaces (BCI) are principally focused on the low and medium range of frequencies whereas there are only a few projects in the high-frequency range...

  4. The Detection of Very Low Frequency Earthquake using Broadband Seismic Array Data in South-Western Japan

    Science.gov (United States)

    Ishihara, Y.; Yamanaka, Y.; Kikuchi, M.

    2002-12-01

    The existences of variety of low-frequency seismic sources are obvious by the dense and equalized equipment_fs seismic network. Kikuchi(2000) and Kumagai et.al. (2001) analyzed about 50sec period ground motion excited by the volcanic activities Miyake-jima, Izu Islands. JMA is listing the low frequency earthquakes routinely in their hypocenter determination. Obara (2002) detected the low frequency, 2-4 Hz, tremor that occurred along subducting Philippine Sea plate by envelope analysis of high dense and short period seismic network (Hi-net). The monitoring of continuos long period waveform show us the existence of many unknown sources. Recently, the broadband seismic network of Japan (F-net, previous name is FREESIA) is developed and extends to linear array about 3,000 km. We reviewed the long period seismic data and earthquake catalogues. Many candidates, which are excited by unknown sources, are picked up manually. The candidates are reconfirmed in detail by the original seismograms and their rough frequency characteristics are evaluated. Most events have the very low frequency seismograms that is dominated period of 20 _E30 sec and smaller amplitude than ground noise level in shorter period range. We developed the hypocenter determination technique applied the grid search method. Moreover for the major events moment tensor inversion was performed. The most source locates at subducting plate and their depth is greater than 30km. However the location don_ft overlap the low frequency tremor source region. Major event_fs moment magnitude is 4 or greater and estimated source time is around 20 sec. We concluded that low frequency seismic event series exist in wide period range in subduction area. The very low frequency earthquakes occurred along Nankai and Ryukyu trough at southwestern Japan. We are planing to survey the very low frequency event systematically in wider western Pacific region.

  5. Term frequency inverse document frequency (TF-IDF) technique and ...

    African Journals Online (AJOL)

    Term frequency inverse document frequency (TF-IDF) technique and artificial neural network in email classification system. ... This has inspired attention for urgent need to manage and maintain e-mail. Email messages are expected to be sent and gathered in a warehouse for recurring use as it ranges from inert institutional ...

  6. Wider-community Segregation and the Effect of Neighbourhood Ethnic Diversity on Social Capital: An Investigation into Intra-Neighbourhood Trust in Great Britain and London.

    Science.gov (United States)

    Laurence, James

    2017-10-01

    Extensive research has demonstrated that neighbourhood ethnic diversity is negatively associated with intra-neighbourhood social capital. This study explores the role of segregation and integration in this relationship. To do so it applies three-level hierarchical linear models to two sets of data from across Great Britain and within London, and examines how segregation across the wider-community in which a neighbourhood is nested impacts trust amongst neighbours. This study replicates the increasingly ubiquitous finding that neighbourhood diversity is negatively associated with neighbour-trust. However, we demonstrate that this relationship is highly dependent on the level of segregation across the wider-community in which a neighbourhood is nested. Increasing neighbourhood diversity only negatively impacts neighbour-trust when nested in more segregated wider-communities. Individuals living in diverse neighbourhoods nested within integrated wider-communities experience no trust-penalty. These findings show that segregation plays a critical role in the neighbourhood diversity/trust relationship, and that its absence from the literature biases our understanding of how ethnic diversity affects social cohesion.

  7. 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.

  8. Simple Models of EMI Filters for Low Frequency Range

    Directory of Open Access Journals (Sweden)

    Z. Raida

    2008-09-01

    Full Text Available This paper deals with mathematical simulations of EMI filters’ performance. These filters are commonly used for the suppressing of electromagnetic interference which penetrates through the power supply networks. The performance of these filters depends on terminating impedances which are plugged to the inputs and outputs clamps of the EMI filters. This paper describes the method by which it is possible to calculate the insertion loss of the filters. The method is based on the modified nodal voltage method. The circuitry of the EMI filters is used for their description. The effect of spurious components is not taken into account. The filter itself is described by set of admittance parameters, which makes the presented method more universal. The calculated results were compared with measured data of several filters for several impedance combinations. Different test setups, like asymmetrical, symmetrical, etc. were taken into account. The simplicity and accuracy of the presented method is discussed in the conclusion. The achieved accuracy is on high level. The described method is universal, but for filters with more than one current compensated inductor, the mentioned method is complicated. The size of the final equation for calculating the insertion loss rapidly increases with the number of current compensated inductors.

  9. High force vibration testing with wide frequency range

    Science.gov (United States)

    Romero, Edward F.; Jepsen, Richard A.; Gregory, Danny Lynn

    2013-04-02

    A shaker assembly for vibration testing includes first and second shakers, where the first shaker includes a piezo-electric material for generating vibration. A support structure permits a test object to be supported for vibration of the test object by both shakers. An input permits an external vibration controller to control vibration of the shakers.

  10. Vibration of railway bridges in the audible frequency range

    OpenAIRE

    Herron, David

    2009-01-01

    The noise level associated with a train travelling on a bridge is normally greater than that for a train travelling on plain track. It is sometimes the bridge noise that causes the highest levels of disturbance to people in the vicinity or triggers action underregulations such as the Environmental Noise Directive. Consequently, there is a need to study means of predicting noise levels from proposed bridges, noise controlmeasures for existing structures and principles of low-noise bridge desig...

  11. Translation and validation of the vertigo symptom scale into German: A cultural adaption to a wider German-speaking population

    Directory of Open Access Journals (Sweden)

    Gloor-Juzi Thomas

    2012-07-01

    Full Text Available Abstract Background Dizziness and comorbid anxiety may cause severe disability of patients with vestibulopathy, but can be addressed effectively with rehabilitation. For an individually adapted treatment, a structured assessment is needed. The Vertigo Symptom Scale (VSS with two subscales assessing vertigo symptoms (VSS-VER and associated symptoms (VSS-AA might be used for this purpose. As there was no validated VSS available in German, the aim of the study was the translation and cross-cultural adaptation in German (VSS-G and the investigation of its reliability, internal and external validity. Methods The VSS was translated into German according to recognized guidelines. Psychometric properties were tested on 52 healthy controls and 202 participants with vestibulopathy. Internal validity and reliability were investigated with factor analysis, Cronbach’s α and ICC estimations. Discriminant validity was analysed with the Mann–Whitney-U-Test between patients and controls and the ROC-Curve. Convergent validity was estimated with the correlation with the Hospital Anxiety Subscale (HADS-A, Dizziness Handicap Inventory (DHI and frequency of dizziness. Results Internal validity: factor analysis confirmed the structure of two subscales. Reliability: VSS-G: α = 0.904 and ICC (CI =0.926 (0.826, 0.965. Discriminant validity: VSS-VER differentiate patients and controls ROC (CI =0.99 (0.98, 1.00. Convergent validity: VSS-G correlates with DHI (r = 0.554 and frequency (T = 0.317. HADS-A correlates with VSS-AA (r = 0.452 but not with VSS-VER (r = 0.186. Conclusions The VSS-G showed satisfactory psychometric properties to assess the severity of vertigo or vertigo-related symptoms. The VSS-VER can differentiate between healthy subjects and patients with vestibular disorders. The VSS-AA showed some screening properties with high sensitivity for patients with abnormal anxiety.

  12. The price of a drink: levels of consumption and price paid per unit of alcohol by Edinburgh's ill drinkers with a comparison to wider alcohol sales in Scotland.

    Science.gov (United States)

    Black, Heather; Gill, Jan; Chick, Jonathan

    2011-04-01

    To compare alcohol purchasing and consumption by ill drinkers in Edinburgh with wider alcohol sales in Scotland. Cross-sectional. Two hospitals in Edinburgh in 2008/09. A total of 377 patients with serious alcohol problems; two-thirds were in-patients with medical, surgical or psychiatric problems due to alcohol; one-third were out-patients. Last week's or typical weekly consumption of alcohol: type, brand, units (1 UK unit 8 g ethanol), purchase place and price. Patients consumed mean 197.7 UK units/week. The mean price paid per unit was £0.43 (lowest £0.09/unit) (£1 = 1.6 US$ or 1.2€), which is below the mean unit price, £0.71 paid in Scotland in 2008. Of units consumed, 70.3% were sold at or below £0.40/unit (mid-range of price models proposed for minimum pricing legislation by the Scottish Government), and 83% at or below £0.50/unit proposed by the Chief Medical Officer of England. The lower the price paid per unit, the more units a patient consumed. A continuous increase in unit price from lower to higher social status, ranked according to the Scottish Index of Multiple Deprivation (based on postcode), was not seen; patients residing in postcodes in the mid-quintile paid the highest price per unit. Cheapness was quoted commonly as a reason for beverage choice; ciders, especially 'white' cider, and vodka were, at off-sales, cheapest per unit. Stealing alcohol or drinking alcohol substitutes was only very rarely reported. Because patients with serious alcohol problems tend to purchase very cheap alcohol, elimination of the cheapest sales by minimum price or other legislation might reduce their consumption. It is unknown whether proposed price legislation in Scotland will encourage patients with serious alcohol problems to start stealing alcohol or drinking substitutes or will reduce the recruitment of new drinkers with serious alcohol problems and produce predicted longer-term gains in health and social wellbeing. © 2010 The Authors, Addiction © 2010

  13. Conducted noise suppression up to GHz range by spin-sprayed Ni{sub 0.2}Zn{sub x}Fe{sub 2.8-x}O{sub 4} (x=0.3, 0.6) films having different natural resonance frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Koichi [NEC Tokin Corporation, 6-7-1 Koriyama, Taihaku-ku, Sendai, Miyagi 982-8510 (Japan)]. E-mail: kondok@nec-tokin.com; Chiba, Tatsuya [NEC Tokin Corporation, 6-7-1 Koriyama, Taihaku-ku, Sendai, Miyagi 982-8510 (Japan); Ono, Hiroshi [NEC Tokin Corporation, 6-7-1 Koriyama, Taihaku-ku, Sendai, Miyagi 982-8510 (Japan); Yoshida, Shigeyoshi [NEC Tokin Corporation, 6-7-1 Koriyama, Taihaku-ku, Sendai, Miyagi 982-8510 (Japan); Shimada, Yutaka [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Sendai, Miyagi 980-8577 (Japan); Matsushita, Nobuhiro [Department of Physical Electronics, Tokyo Institute of technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Abe, Masanori [Department of Physical Electronics, Tokyo Institute of technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2006-06-15

    In order to apply to a novel, flexible type of GHz noise suppressors, we prepared Ni{sub 0.2}Zn{sub x}Fe{sub 2.8-x}O{sub 4} films with x=0.3 and 0.6 and thicknesses of 2 and 5{mu}m, by spin spray ferrite plating from an aqueous solution on polyimide sheets at 90 deg. C. Placing the films onto a microstrip line, we measured transmission loss {delta}P{sub loss} and reflection parameter S{sub 11} at 10MHz-10GHz. As x increased from 0.3 to 0.6, f{sub r} (natural resonance frequency) decreased from 350 to 50MHz, which resulted in decreasing f{sub c} (a frequency from which {delta}P{sub loss} begins rising) from 400 to 100MHz. This means we can tune f{sub c} of the films by changing the Zn concentration x. At 8GHz, {delta}P{sub loss} obtained by the ferrite films increased from 40% to 70% when their thickness increased from 2 to 5{mu}m. We obtained S{sub 11}<10%, irrespective of Zn concentration, in the whole measurement frequency range. By the films with x=0.3 and 2{mu}m thickness we obtained {delta}P{sub loss}=40%, which was as strong as that obtained by a commercially available composite sheet type noise suppressor of 25{mu}m thickness that are made of ferromagnetic metal flakes embedded in a flexible polymer matrix. Moreover, {delta}P{sub loss} by the ferrite film increased to 70% when the thickness was increased to 5{mu}m. Therefore, our NiZn ferrite films are promising to be actually used as GHz noise suppressors with tunable working frequencies that exhibit stronger noise suppression than the commercialized composite type of noise suppressors.

  14. CLIMATIC SIGNALS FROM INTRA-ANNUAL DENSITY FLUCTUATION FREQUENCY IN MEDITERRANEAN PINES AT A REGIONAL SCALE

    Directory of Open Access Journals (Sweden)

    Enrica eZalloni

    2016-05-01

    Full Text Available Tree rings provide information about the climatic conditions during the growing season by recording them in different anatomical features, such as Intra-Annual Density Fluctuations (IADFs. IADFs are intra-annual changes of wood density appearing as latewood-like cells within earlywood, or earlywood-like cells within latewood. The occurrence of IADFs is dependent on the age and size of the tree, and it is triggered by climatic drivers. The variations of IADF frequency of different species and their dependence on climate across a wide geographical range have still to be explored. The objective of this study is to investigate the effect of age, tree-ring width and climate on IADF formation and frequency at a regional scale across the Mediterranean Basin in Pinus halepensis Mill., Pinus pinaster Ait. and Pinus pinea L. The analyzed tree-ring network was composed of P. pinea trees growing at 11 sites (2 in Italy, 4 in Spain and 4 in Portugal, P. pinaster from 19 sites (2 in Italy, 13 in Spain and 4 in Portugal, and P. halepensis from 38 sites in Spain. The correlations between IADF frequency and monthly minimum, mean and maximum temperatures, as well as between IADF frequency and total precipitation, were analyzed. A significant negative relationship between IADF frequency and tree-ring age was found for the three Mediterranean pines. Moreover, IADFs were more frequent in wider rings than in narrower ones, although the widest rings showed a reduced IADF frequency. Wet conditions during late summer/early autumn triggered the formation of IADFs in the three species. Our results suggest the existence of a common climatic driver for the formation of IADFs in Mediterranean pines, highlighting the potential use of IADF frequency as a proxy for climate reconstructions with geographical resolution.

  15. Climatic Signals from Intra-annual Density Fluctuation Frequency in Mediterranean Pines at a Regional Scale.

    Science.gov (United States)

    Zalloni, Enrica; de Luis, Martin; Campelo, Filipe; Novak, Klemen; De Micco, Veronica; Di Filippo, Alfredo; Vieira, Joana; Nabais, Cristina; Rozas, Vicente; Battipaglia, Giovanna

    2016-01-01

    Tree rings provide information about the climatic conditions during the growing season by recording them in different anatomical features, such as intra-annual density fluctuations (IADFs). IADFs are intra-annual changes of wood density appearing as latewood-like cells within earlywood, or earlywood-like cells within latewood. The occurrence of IADFs is dependent on the age and size of the tree, and it is triggered by climatic drivers. The variations of IADF frequency of different species and their dependence on climate across a wide geographical range have still to be explored. The objective of this study is to investigate the effect of age, tree-ring width and climate on IADF formation and frequency at a regional scale across the Mediterranean Basin in Pinus halepensis Mill., Pinus pinaster Ait., and Pinus pinea L. The analyzed tree-ring network was composed of P. pinea trees growing at 10 sites (2 in Italy, 4 in Spain, and 4 in Portugal), P. pinaster from 19 sites (2 in Italy, 13 in Spain, and 4 in Portugal), and P. halepensis from 38 sites in Spain. The correlations between IADF frequency and monthly minimum, mean and maximum temperatures, as well as between IADF frequency and total precipitation, were analyzed. A significant negative relationship between IADF frequency and tree-ring age was found for the three Mediterranean pines. Moreover, IADFs were more frequent in wider rings than in narrower ones, although the widest rings showed a reduced IADF frequency. Wet conditions during late summer/early autumn triggered the formation of IADFs in the three species. Our results suggest the existence of a common climatic driver for the formation of IADFs in Mediterranean pines, highlighting the potential use of IADF frequency as a proxy for climate reconstructions with geographical resolution.

  16. Determination of Equine Cytochrome c Backbone Amide Hydrogen/Deuterium Exchange Rates by Mass Spectrometry Using a Wider Time Window and Isotope Envelope

    Science.gov (United States)

    Hamuro, Yoshitomo

    2017-03-01

    A new strategy to analyze amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) data is proposed, utilizing a wider time window and isotope envelope analysis of each peptide. While most current scientific reports present HDX-MS data as a set of time-dependent deuteration levels of peptides, the ideal HDX-MS data presentation is a complete set of backbone amide hydrogen exchange rates. The ideal data set can provide single amide resolution, coverage of all exchange events, and the open/close ratio of each amide hydrogen in EX2 mechanism. Toward this goal, a typical HDX-MS protocol was modified in two aspects: measurement of a wider time window in HDX-MS experiments and deconvolution of isotope envelope of each peptide. Measurement of a wider time window enabled the observation of deuterium incorporation of most backbone amide hydrogens. Analysis of the isotope envelope instead of centroid value provides the deuterium distribution instead of the sum of deuteration levels in each peptide. A one-step, global-fitting algorithm optimized exchange rate and deuterium retention during the analysis of each amide hydrogen by fitting the deuterated isotope envelopes at all time points of all peptides in a region. Application of this strategy to cytochrome c yielded 97 out of 100 amide hydrogen exchange rates. A set of exchange rates determined by this approach is more appropriate for a patent or regulatory filing of a biopharmaceutical than a set of peptide deuteration levels obtained by a typical protocol. A wider time window of this method also eliminates false negatives in protein-ligand binding site identification.

  17. The wider use of fixed-dose combinations emphasizes the need for a global approach to regulatory guideline development

    DEFF Research Database (Denmark)

    Gautam, Yvonne; Bjerrum, Ole Jannik; Schmiegelow, Merete

    2015-01-01

    face the regulatory world: how to improve the role of regulatory science and provide clear quantification in assessment decisions; the role of guidelines and their impact on innovation; and, most important, the question of globalization and how to move toward a more harmonized regulatory system.......A fixed-dose combination (FDC) is a drug product in which two or more separate drug components (active pharmaceutical ingredients) are combined in a single-dosage form. Interest in developing FDCs is increasing in a range of diseases. This project investigated the regulatory environment for FDCs....... It was clear from the results that the current regulatory environment for FDCs lacks consistency. This may create a barrier to innovation moving from the laboratory to the clinic, as companies cannot clearly see the development path requirements. This project also highlighted certain challenges that currently...

  18. Swiss Life Sciences - a science communication project for both schools and the wider public led by the foundation Science et Cité.

    Science.gov (United States)

    Röthlisberger, Michael

    2012-01-01

    The foundation Science et Cité was founded 1998 with the aim to inform the wider Swiss public about current scientific topics and to generate a dialogue between science and society. Initiated as an independent foundation by the former State Secretary for Science and Research, Dr. Charles Kleiber, Science et Cité is now attached to the Swiss Academies of Arts and Sciences as a competence center for dialogue with the public. Due to its branches in all language regions of the country, the foundation is ideally suited to initiate and implement communication projects on a nationwide scale. These projects are subdivided into three categories: i) science communication for children/adolescents, ii) establishing a dialogue between science and the wider public, and iii) conducting the role of a national center of competence and networking in science communication. Swiss Life Sciences is a project that fits into all of these categories: a year-round program for schools is complemented with an annual event for the wider public. With the involvement of most of the major Swiss universities, the Swiss National Science Foundation, the foundation Gen Suisse and many other partners, Swiss Life Sciences also sets an example of national networking within the science communication community.

  19. Toward an alternative evolutionary theory of religion: looking past computational evolutionary psychology to a wider field of possibilities.

    Science.gov (United States)

    Barrett, Nathaniel F

    2010-01-01

    Cognitive science of the last half-century has been dominated by the computational theory of mind and its picture of thought as information processing. Taking this picture for granted, the most prominent evolutionary theories of religion of the last fifteen years have sought to understand human religiosity as the product or by-product of universal information processing mechanisms that were adaptive in our ancestral environment. The rigidity of such explanations is at odds with the highly context-sensitive nature of historical studies of religion, and thus contributes to the apparent tug-of-war between scientific and humanistic perspectives. This essay argues that this antagonism stems in part from a deep flaw of computational theory, namely its notion of information as pre-given and context-free. In contrast, non-computational theories that picture mind as an adaptive, interactive process in which information is jointly constructed by organism and environment offer an alternative approach to an evolutionary understanding of human religiosity, one that is compatible with historical studies and amenable to a wide range of inquiries, including some limited kinds of theological inquiry.

  20. Measurement of Line-to-Ground Capacitance in Distribution Network Considering Magnetizing Impedance’s Frequency Characteristic

    Directory of Open Access Journals (Sweden)

    Qing Yang

    2017-04-01

    Full Text Available Signal injection method (SIM is widely applied to the insulation parameters’ measurement in distribution network for its convenience and safety. It can be divided into two kinds of patterns: injecting a specific frequency signal or several frequencies’ groups, and scanning frequency in a scheduled frequency scope. In order to avoid the disadvantages in related researches, improved signal injection method (ISIM, in which the frequency characteristic of the transformer magnetizing impedance is taken into consideration, is proposed. In addition, optimization for signal injection position has been accomplished, and the corresponding three calculation methods of line-to-ground capacitance has been derived. Calculations are carried out through the vector information (vector calculation method, the amplitude information (amplitude calculation method, the phase information (phase calculation method of voltage and current in signal injecting port, respectively. The line-to-ground capacitance is represented by lumped parameter capacitances in high-voltage simulation test. Eight different sinusoidal signals are injected into zero-sequence circuit, and then line-to-ground capacitance is calculated with the above-mentioned vector calculation method based on the voltage and the current data of the injecting port. The results obtained by the vector calculation method show that ISIM has a wider application frequency range compared with signal injection method with rated parameters (RSIM and SIM. The RSIM is calculated with the rated transformer parameters of magnetizing impedance, and the SIM based on the ideal transformer model, and the relative errors of calculation results of ISIM are smaller than that for other methods in general. The six groups of two-frequency set are chosen in a specific scope which is recommended by vector calculation results. Based on ISIM, the line-to-ground capacitance calculations through the amplitude calculation method and

  1. Study of the dielectric and magnetic properties of Co{sub 2}Y, Y-type hexaferrite (Ba{sub 2}Co{sub 2}Fe{sub 12}O{sub 22}) added with PbO and Bi{sub 2}O{sub 3} in the RF frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Pires, G.F.M.; Rodrigues, H.O. [Departamento de Engenharia de Teleinformatica (DETI), Universidade Federal do Ceara (UFC), CEP 60455-760, Fortaleza, Ceara (Brazil); Laboratorio de Telecomunicacoes e Ciencias e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara (UFC), Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil); Almeida, J.S.; Sancho, E.O.; Goes, J.C. [Laboratorio de Telecomunicacoes e Ciencias e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara (UFC), Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil); Costa, M.M. [Departamento de Fisica, Universidade Federal de Mato Grosso (UFMT), Cuiaba (Brazil); Denardin, J.C. [Universidad de Santiago de Chile, Departamento de Fisica, Avenida Ecuador 3493, Estacion Central, Santiago (Chile); Sombra, A.S.B., E-mail: sombra@ufc.b [Laboratorio de Telecomunicacoes e Ciencias e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara (UFC), Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil)

    2010-03-18

    In this paper the magnetic and dielectric properties of Y-type hexaferrite (Co{sub 2}Y:Ba{sub 2}Co{sub 2}Fe{sub 12}O{sub 22}) added with 3, 5 and 10 wt.% of PbO and Bi{sub 2}O{sub 3}, obtained in a new procedure of the solid-state method, is presented. The analysis by X-ray diffraction (XRD) using the Rietveld refinement confirmed the formation of single-phase compound with a hexagonal crystal structure (a = b = 5.8560 A and c = 43.4977 A; {alpha} = {beta} = 90{sup o} and {gamma} = 120{sup o}). SEM micrograph of the material shows an uniform distribution of grains throughout the surface of the samples. Detailed studies of the dielectric properties of Co{sub 2}Y, investigated in a wide frequency range (100 Hz to 100 MHz) at room temperature by complex impedance spectroscopy (CIS) technique, showed that these properties are strongly dependent on frequency and on the added level of the impurity. The effect of polyvinyl alcohol (PVA) and tetraethyl orthosilicate (TEOS) on the properties of Co{sub 2}Y hexaferrite was also studied.

  2. Climate Impacts on Sea Turtle Breeding Phenology in Greece and Associated Foraging Habitats in the Wider Mediterranean Region.

    Directory of Open Access Journals (Sweden)

    Samir H Patel

    Full Text Available Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5 of loggerhead turtles (Caretta caretta nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N, a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N and Rethymno, Crete (latitude: 35.4°N. We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC, we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°-45.8°N for loggerhead turtles nesting in Greece will rise by 3-5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50-74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population.

  3. Digital frequency control of satellite frequency standards. [Defense Navigation Satellites

    Science.gov (United States)

    Nichols, S. A.

    1973-01-01

    In the Frequency and Time Standard Development Program of the TIMATION System, a new miniaturized rubidium vapor frequency standard has been tested and analyzed for possible use on the TIMATION 3A launch, as part of the Defense Navigation Satellite Development Program. The design and construction of a digital frequency control was required to remotely control this rubidium vapor frequency standard as well as the quartz oscillator in current use. This control must be capable of accepting commands from a satellite telemetry system, verify that the correct commands have been sent and control the frequency to the requirements of the system. Several modifications must be performed to the rubidium vapor frequency standard to allow it to be compatible with the digital frequency control. These include the addition of a varactor to voltage tune the coarse range of the flywheel oscillator, and a modification to supply the C field current externally. The digital frequency control for the rubidium vapor frequency standard has been successfully tested in prototype form.

  4. 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

  5. The frequency of a disease-causing point mutation in the gene coding for medium-chain acyl-CoA dehydrogenase in sudden infant death syndrome

    DEFF Research Database (Denmark)

    Banner, Jytte; Gregersen, N; Kølvraa, S

    1993-01-01

    A number of rare inherited metabolic disorders are known to lead to death in infancy. Deficiency of medium-chain acyl CoA dehydrogenase has, on clinical grounds, been related particularly to sudden infant death syndrome. The contribution of this disorder to the etiology of sudden infant death...... syndrome is still a matter of controversy. The present study investigated 120 well-defined cases of sudden infant death syndrome in order to detect the frequency of the most common disease-causing point mutation in the gene coding for medium-chain acyl-CoA dehydrogenase (G985) compared with the frequency...... presentations of inherited metabolic disorders and examine a wider range of sudden death in infancy....

  6. 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

  7. Normative voice range profiles in vocally trained and untrained children aged between 7 and 10 years.

    Science.gov (United States)

    Schneider, Berit; Zumtobel, Michaela; Prettenhofer, Walter; Aichstill, Birgitta; Jocher, Werner

    2010-03-01

    Only limited data on normal vocal constitution and vocal capabilities in school-aged children are available. To take better care of children's voices, it might be helpful to know voice ranges and limits of not only vocally trained but also vocally untrained children. Goal of this study was the evaluation of singing voice capabilities of vocally healthy children with different social and vocal/musical backgrounds using voice range profile measurements (VRP). VRP percentiles that reflect constitutional aspects were suggested. In this cross-sectional study, 186 children (aged between seven and 10 years), attending five schools, were included. VRP measurements were performed under field conditions. Interviews and questionnaires regarding vocal strain and vocal training were applied; the answers were used for classification of singing activity and vocal training (KLASAK). All children reached a mean singing voice range of at least two octaves. By using the answers of interviews and questionnaires, the children could be classified according to vocal strain and vocal training. The groups showed no significant differences regarding VRP measurements. In the following step, percentiles were calculated. Twenty-five percent of all children (P25) reached a minimum voice range of almost two octaves, namely, 22 semitones (ST) from 220 to 784 Hz with soft and loud singing. Half of the children (P50) had a voice range of 24 ST (2 octaves), while soft singing and a larger voice range of 26 ST while loud singing. The measurements of third quartile (P75) revealed that 25% of children have even a larger voice range than 29 dB (from 196 Hz/g to 1047 Hz/c3) and can sing at most frequencies louder than 90 dB. P90 demonstrated that 10% of the children can sing even lower or higher than the frequency range between 196 Hz/g and 1319 Hz/e3 analyzed. The voice range seems not to be constrained by social but by voice/musical background: children of vocally/musically encouraged schools had wider

  8. Simplified loss analysis and comparison of full-bridge, full-range ...

    Indian Academy of Sciences (India)

    The loss of zero-voltage-switching (ZVS) of active switches has been a serious limitation of full-bridge (FBZVS) converters. Many techniques have been proposed in the past to extend the range of ZVS operation over the wider and also the full range of operation. However, in these techniques ZVS is achieved at the expense ...

  9. Success-slope effects on the illusion of control and on remembered success-frequency

    Directory of Open Access Journals (Sweden)

    Anastasia Ejova

    2013-07-01

    Full Text Available The illusion of control refers to the inference of action-outcome contingency in situations where outcomes are in fact random. The strength of this illusion has been found to be affected by whether the frequency of successes increases or decreases over repeated trials, in what can be termed a ``success-slope'' effect. Previous studies have generated inconsistent findings regarding the nature of this effect. In this paper we present an experiment (N = 334 that overcomes several methodological limitations within this literature, employing a wider range of dependent measures (measures of two different types of illusory control, primary (by self and secondary (by luck, as well as measures of remembered success-frequency. Results indicate that different dependent measures lead to different effects. On measures of (primary, but not secondary control over the task, scores were highest when the rate of success increased over time. Meanwhile, estimates of success-frequency in the task did not vary across conditions and showed trends consistent with the broader literature on human memory.

  10. Radio pill antenna range test

    Science.gov (United States)

    Cummins, W. F.; Kane, R. J.

    1992-05-01

    In order to investigate the potential of a proposed 'radio pill' beacon transmitter, a range test experiment was devised and carried out in the VHF frequency range. Calculations and previous work indicated that optimum sensitivity and, thus, distance would be obtained in this frequency range provided body radio-frequency (RF) absorption was not too great. A ferrite-core loop antenna is compatible with a pill geometry and has better radiation efficiency than an air core loop. The ferrite core may be a hollow cylinder with the electronics and batteries placed inside. However, this range test was only concerned with experimentally developing test range data on the ferrite core antenna itself. A one turn strap loop was placed around a 9.5 mm diameter by 18.3 mm long stack of ferrite cores. This was coupled to a 50 Omega transmission line by 76 mm of twisted pair line and a capacitive matching section. This assembly was excited by a signal generator at output levels of -10 to +10 dBm. Signals were received on a VHF receiver and tape recorder coupled to a 14 element, circularly polarized Yagi antenna at a height of 2.5 m. Field strength measurements taken at ranges of 440, 1100, and 1714 m. Maximum field strengths referenced to 0 dBm transmitter level were -107 to -110 dB at 440 m, -124 to -127 dBm at 1100 m, and -116 to -119 dBm at 1714 m when the antenna cylinder was horizontal. Field strengths with a vertical antenna were about 6 dB below these values. The latter transmit site was elevated and had a clear line-of-site path to the receiving site. The performance of this test antenna was better than that expected from method-of-moment field calculations. When this performance data is scaled to a narrow bandwidth receiving system, ground level receiving ranges of a few to 10 km can be expected. Clear line-of-sight ranges where either or both the transmitter and receiver are elevated could vary from several km to 100 km.

  11. Extensive range overlap between heliconiine sister species: evidence for sympatric speciation in butterflies?

    Science.gov (United States)

    Rosser, Neil; Kozak, Krzysztof M; Phillimore, Albert B; Mallet, James

    2015-06-30

    Sympatric speciation is today generally viewed as plausible, and some well-supported examples exist, but its relative contribution to biodiversity remains to be established. We here quantify geographic overlap of sister species of heliconiine butterflies, and use age-range correlations and spatial simulations of the geography of speciation to infer the frequency of sympatric speciation. We also test whether shifts in mimetic wing colour pattern, host plant use and climate niche play a role in speciation, and whether such shifts are associated with sympatry. Approximately a third of all heliconiine sister species pairs exhibit near complete range overlap, and analyses of the observed patterns of range overlap suggest that sympatric speciation contributes 32%-95% of speciation events. Müllerian mimicry colour patterns and host plant choice are highly labile traits that seem to be associated with speciation, but we find no association between shifts in these traits and range overlap. In contrast, climatic niches of sister species are more conserved. Unlike birds and mammals, sister species of heliconiines are often sympatric and our inferences using the most recent comparative methods suggest that sympatric speciation is common. However, if sister species spread rapidly into sympatry (e.g. due to their similar climatic niches), then assumptions underlying our methods would be violated. Furthermore, although we find some evidence for the role of ecology in speciation, ecological shifts did not show the associations with range overlap expected under sympatric speciation. We delimit species of heliconiines in three different ways, based on "strict and " "relaxed" biological species concepts (BSC), as well as on a surrogate for the widely-used "diagnostic" version of the phylogenetic species concept (PSC). We show that one reason why more sympatric speciation is inferred in heliconiines than in birds may be due to a different culture of species delimitation in the two

  12. The price of a drink: levels of consumption and price paid per unit of alcohol by Edinburgh's ill drinkers with a comparison to wider alcohol sales in Scotland

    OpenAIRE

    Black, Heather; Gill, Jan; Chick, Jonathan

    2011-01-01

    Aim To compare alcohol purchasing and consumption by ill drinkers in Edinburgh with wider alcohol sales in Scotland.\\ud \\ud Design Cross-sectional.\\ud \\ud Setting Two hospitals in Edinburgh in 2008/09.\\ud \\ud Participants A total of 377 patients with serious alcohol problems; two-thirds were in-patients with medical, surgical or psychiatric problems due to alcohol; one-third were out-patients.\\ud \\ud Measurements Last week's or typical weekly consumption of alcohol: type, brand, units (1 UK u...

  13. Range management visual impacts

    Science.gov (United States)

    Bruce R. Brown; David Kissel

    1979-01-01

    Historical overgrazing of western public rangelands has resulted in the passage of the Public Rangeland Improvement Act of 1978. The main purpose of this Act is to improve unsatisfactory range conditions. A contributing factor to unfavorable range conditions is adverse visual impacts. These visual impacts can be identified in three categories of range management: range...

  14. Spectrally resolved frequency comb interferometry

    Science.gov (United States)

    van den Berg, S.

    2014-04-01

    In this contribution a novel method for interferometric distance measurement is presented, that is based on unraveling the spectrum of a femtosecond frequency comb. The light of a frequency comb is sent into a Michelson interferometer. The output of the interferometer is analyzed by a high-resolution spectrometer, resolving the individual comb modes. The path-length difference between the two arms is determined on the level of tens of nm, by utilizing the wealth of information present in the unraveled spectrum, showing homodyne interference for each individual frequency comb mode. The measurement method allows for high-accuracy measurements in combination with a large range of non-ambiguity.

  15. Frequency synthesizers concept to product

    CERN Document Server

    Chenakin, Alexander

    2011-01-01

    A frequency synthesizer is an electronic system for generating any of a range of frequencies from a single fixed oscillator. They are found in modern devices like radio receivers, mobile phones, and GPS systems. This comprehensive resource offers RF and microwave engineers a thorough overview of both well-established and recently developed frequency synthesizer design techniques. Professionals find expert guidance on all design aspects, including main architectures, key building blocks, and practical circuit implementation. Engineers learn the development process and gain a solid understanding

  16. The regulatory framework of the radio frequency spectrum under ...

    African Journals Online (AJOL)

    The Radio Frequency Spectrum (R.F.S) is the entire range of wavelengths of electromagnetic radiation in the frequency range of 3 kilohertz (KHZ) to 40,000 megahertz (MHZ). The RFS is arbitrarily divided into a number of wavebands, from very low frequencies (long wavelengths) to ultra-high and microwave frequencies ...

  17. Phonotactic selectivity in two cryptic species of gray treefrogs: effects of differences in pulse rate, carrier frequency and playback level.

    Science.gov (United States)

    Gerhardt, H Carl

    2008-08-01

    The two main spectral components of the advertisement calls of two species of North American gray treefrogs (Hyla chrysoscelis and H. versicolor) overlap broadly in frequency, and the frequency of each component matches the sensitivity of one of the two different auditory inner ear organs. The calls of the two species differ in the shape and repetition rate (pulse rate) of sound pulses within trills. Standard synthetic calls with one of these spectral peaks and the pulse rate typical of conspecific calls were tested against synthetic alternatives that had the same spectral peak but a different pulse rate. The results were generalized over a wide range of playback levels. Selectivity based on differences in pulse rate depended on which spectral peak was used in some tests, and greater pulse-rate selectivity was usually observed when the low-frequency rather than the high-frequency peak was used. This effect was more pronounced and occurred over a wider range of playback levels in H. versicolor than in H. chrysoscelis when the pulse rate of the alternative was higher than that of the standard call. In tests at high playback levels with an alternative of 15 pulses s(-1), however, females of H. versicolor showed greater selectivity for the standard call when the high-frequency rather than the low-frequency spectral peak was used. This last result may reflect the different ways in which females of the two species assess trains of pulses, and the broad implications for understanding the underlying auditory mechanisms are discussed.

  18. Wider benefits of adult education

    DEFF Research Database (Denmark)

    Schuller, Tom; Desjardins, Richard

    2010-01-01

    This article discusses the measurement of the social outcomes of learning. It extends the discussion beyond employment and labor market outcomes to consider the impact of adult learning on social domains, with particular focus on health and civic engagement. It emphasizes the distinction between...... public and private, and monetary and nonmonetary benefits. It reviews methodological issues on measuring outcomes, and identifies a number of channels through which adult learning has its effects....

  19. Wider den Klima-Totalitarismus

    CERN Multimedia

    Gärtner, Edgar

    2006-01-01

    The Kyoto Protocol in 1997 has turned out unsuitable, thinks Edgar Gärtner. The director of the ecological forum of the Centre for the new Europe in Bruxelles explains how for him successful protection of the atmosphere looks essential. (1/2 page)

  20. Multifractal Geophysical Extremes: Nonstationarity and Long Range Correlations

    Science.gov (United States)

    Tchiguirinskaia, I.; Schertzer, D.; Lovejoy, S.

    2012-04-01

    Throughout the world, extremes in environmental sciences are of prime importance. They are key variables not only for risk assessments and engineering designs (e.g. of dams and bridges), but also for resource management (e.g. water and energy) and for land use. A better understanding of them is more and more indispensable in settling the debate on their possible climatological evolution. Whereas it took decades before a uniform technique for estimating flow frequencies within a stationary framework, it is often claimed that « stationarity is dead ! ». The fact that geophysical and environmental fields are variable over a wider range of scales than previously thought require to go beyond the limits of the (classical) Extreme Value Theory (EVT). Indeed, long-range correlations are beyond the scope of the classical EVT theory. We show that multifractal concepts and techniques are particularly appealing because they can effectively deal with a cascade of interactions concentrating for instance energy, liquid water, etc. into smaller and smaller space-time domains. Furthermore, a general outcome of these cascade processes -which surprisingly was realized only rather recently- is that rather independently of their details they yield probability distributions with power-law fall-offs, often called (asymptotic) Pareto or Zipf laws. We discuss the corresponding probability distributions of their maxima and its relationship with the Frechet law. We use these multifractal techniques to investigate the possibility of using very short or incomplete data records for reliable statistical predictions of the extremes. In particular we assess the multifractal parameter uncertainty with the help of long synthetic multifractal series and their sub-samples, in particular to obtain an approximation of confidence intervals that would be particularly important for the predictions of multifractal extremes. We finally illustrate the efficiency of this approach with its application to

  1. Minnesota Pheasant Range

    Data.gov (United States)

    Minnesota Department of Natural Resources — This dataset delineates the spatial range of wild pheasant populations in Minnesota as of 2002 by dividing the MN state boundary into 2 units: pheasant range and...

  2. 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...... to a new problem, which we call substring range reporting. Hence, we unify the previous work by showing that we may restrict our attention to a single problem rather than studying each of the above problems individually. We show how to solve substring range reporting with optimal query time and little...... for substring range reporting generalize to substring range counting and substring range emptiness variants. We also obtain non-trivial time-space trade-offs for these problems. Our bounds for substring range reporting are based on a novel combination of suffix trees and range reporting data structures...

  3. 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...

  4. 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 <15% of all 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 < 0.05). Identifying the causes of inter-individual variation in ranging behaviour may help optimise ranging opportunities in free-range systems and is important to elucidate the potential welfare implications of ranging.

  5. Principles of digital dynamic-range compression.

    Science.gov (United States)

    Kates, James M

    2005-01-01

    This article provides an overview of dynamic-range compression in digital hearing aids. Digital technology is becoming increasingly common in hearing aids, particularly because of the processing flexibility it offers and the opportunity to create more-effective devices. The focus of the paper is on the algorithms used to build digital compression systems. Of the various approaches that can be used to design a digital hearing aid, this paper considers broadband compression, multi-channel filter banks, a frequency-domain compressor using the FFT, the side-branch design that separates the filtering operation from the frequency analysis, and the frequency-warped version of the side-branch approach that modifies the analysis frequency spacing to more closely match auditory perception. Examples of the compressor frequency resolution, group delay, and compression behavior are provided for the different design approaches.

  6. Swept Frequency Laser Metrology System

    Science.gov (United States)

    Zhao, Feng (Inventor)

    2010-01-01

    A swept frequency laser ranging system having sub-micron accuracy that employs multiple common-path heterodyne interferometers, one coupled to a calibrated delay-line for use as an absolute reference for the ranging system. An exemplary embodiment uses two laser heterodyne interferometers to create two laser beams at two different frequencies to measure distance and motions of target(s). Heterodyne fringes generated from reflections off a reference fiducial X(sub R) and measurement (or target) fiducial X(sub M) are reflected back and are then detected by photodiodes. The measured phase changes Delta phi(sub R) and Delta phi (sub m) resulting from the laser frequency swept gives target position. The reference delay-line is the only absolute reference needed in the metrology system and this provides an ultra-stable reference and simple/economical system.

  7. Method and apparatus for coherent burst ranging

    Science.gov (United States)

    Wachter, Eric A.; Fisher, Walter G.

    1998-01-01

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.

  8. Frequency-Domain Transient Imaging.

    Science.gov (United States)

    Jingyu Lin; Yebin Liu; Jinli Suo; Qionghai Dai

    2017-05-01

    A transient image is the optical impulse response of a scene, which also visualizes the propagation of light during an ultra-short time interval. In contrast to the previous transient imaging which samples in the time domain using an ultra-fast imaging system, this paper proposes transient imaging in the frequency domain using a multi-frequency time-of-flight (ToF) camera. Our analysis reveals the Fourier relationship between transient images and the measurements of a multi-frequency ToF camera, and identifies the causes of the systematic error-non-sinusoidal and frequency-varying waveforms and limited frequency range of the modulation signal. Based on the analysis we propose a novel framework of frequency-domain transient imaging. By removing the systematic error and exploiting the harmonic components inside the measurements, we achieves high quality reconstruction results. Moreover, our technique significantly reduces the computational cost of ToF camera based transient image reconstruction, especially reduces the memory usage, such that it is feasible for the reconstruction of transient images at extremely small time steps. The effectiveness of frequency-domain transient imaging is tested on synthetic data, real data from the web, and real data acquired by our prototype camera.

  9. Reticle level compensation for long range effects

    Science.gov (United States)

    Figueiro, Thiago; Browning, Clyde; Thornton, Martin J.; Vannufel, Cyril; Schiavone, Patrick

    2013-03-01

    Proximity Effects in electron beam lithography impact feature dimensions, pattern fidelity and uniformity. Electron scattering effects are commonly addressed using a mathematical model representing the radial exposure intensity distribution induced by a point electron source, commonly named Point Spread Function (PSF). PSF models are usually employed for correcting "short-range" and "long-range" backscattering effects up to 10μm to 15μm. It is well known that there are also some process related phenomena impacting pattern uniformity that have a wider range (fogging, chemical mechanical polishing -CMP- effects, etc.) which impacts up to a few millimeters or more. There are a number of commercial strategies for mitigating such long range effects based on data density. However, those traditional ones are usually performed within a single chip on a reticle field and ignore the presence of adjacent fields, neglecting their influence. Full field reticles can contain several different designs or arrayed chips in a multitude of layout placements. Reticle level jobdeck placing each design at specific sites, independent of each other can be used to account for the density of each pattern that has a relative impact on its neighbors, even if they are several millimeters away from offending data. Therefore, full field density analysis accounting for scribe frames and all neighboring patterns is required for reaching fidelity control requirements such as critical dimension (CD) and line end shortening (LES) on the full plate. This paper describes a technique to compensate long range effects going across chip boundaries to the full reticle exposure field. The extreme long range effects are also represented with a model that is calibrated according to the characteristics of the user's process. Data correction can be based on dose and geometry modulation. Uniform pattern dimensional control matching the user's specific process long range variability can be achieved with the

  10. 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...... to a new problem, which we call substring range reporting. Hence, we unify the previous work by showing that we may restrict our attention to a single problem rather than studying each of the above problems individually. – We show how to solve substring range reporting with optimal query time and little...... range reporting are based on a novel combination of suffix trees and range reporting data structures. The reductions are simple and general and may apply to other combinations of string indexing with range reporting....

  11. Multifractal Flood Frequency Analysis

    Science.gov (United States)

    Tchiguirinskaia, I.; Schertzer, D.; Lovejoy, S.

    2007-12-01

    Hydrology and more generally sciences involved in water resources management, researches and technological or operational development face a fundamental difficulty: the extreme variability of hydrological fields. It clearly appears today that this variability is a function of the observation scale and yield natural hazards such as floods or droughts. The estimation of return periods for extreme precipitation and flooding events requires a model of the natural (unperturbed) statistical behaviour of the probability tails and the possible clustering (including possible long-range dependencies) of the extremes. Appropriate approaches for handling such non classical variability over wide ranges of time and space scale do exist. They are based on a fundamental property of the non-linear equations: scale invariance. Its specific framework is that of multifractals. In this framework hydrological variability builds up scale by scale leading to non-classical statistics; this provides the key element needed to better understand and predict floods. Scaling is a verifiable physical principle which can be exploited to model hydrological processes and estimate their statistics over wide ranges of space-time scales. We first present the Multifractal Flood Frequency Analysis (MFFA) tool and illustrate some results of its application to a large database (for more than 16000 selected stations over USA and Canada). We then discuss its efficiency by showing how the mean flow information - coupled with universal multifractal parametrizations with power law tails - can be used to estimate return times for extreme flood events.

  12. 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...

  13. 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...

  14. Neutron diffraction study of the magnetic long-range order in Tb

    DEFF Research Database (Denmark)

    Dietrich, O.W.; Als-Nielsen, Jens Aage

    1967-01-01

    and implies no change in the long-range order. In the close vicinity of the Neacuteel temperature TN = 226deg K the spiral magnetic long-range order varies as (TN-T)0.25plusmn 0.01, whereas the total order within a wider temperature range roughly follows (TN-T)1/3. The turn angle per layer varies from 16.5deg...

  15. 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

  16. 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...

  17. 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.

  18. High frequency nanotube oscillator

    Science.gov (United States)

    Peng, Haibing [Houston, TX; Zettl, Alexander K [Kensington, TX

    2012-02-21

    A tunable nanostructure such as a nanotube is used to make an electromechanical oscillator. The mechanically oscillating nanotube can be provided with inertial clamps in the form of metal beads. The metal beads serve to clamp the nanotube so that the fundamental resonance frequency is in the microwave range, i.e., greater than at least 1 GHz, and up to 4 GHz and beyond. An electric current can be run through the nanotube to cause the metal beads to move along the nanotube and changing the length of the intervening nanotube segments. The oscillator can operate at ambient temperature and in air without significant loss of resonance quality. The nanotube is can be fabricated in a semiconductor style process and the device can be provided with source, drain, and gate electrodes, which may be connected to appropriate circuitry for driving and measuring the oscillation. Novel driving and measuring circuits are also disclosed.

  19. 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.

  20. 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

  1. Digital Low Frequency Radio Camera

    Science.gov (United States)

    Fullekrug, M.; Mezentsev, A.; Soula, S.; van der Velde, O.; Poupeney, J.; Sudre, C.; Gaffet, S.; Pincon, J.

    2012-04-01

    This contribution reports the design, realization and operation of a novel digital low frequency radio camera towards an exploration of the Earth's electromagnetic environment with particular emphasis on lightning discharges and subsequent atmospheric effects such as transient luminous events. The design of the digital low frequency radio camera is based on the idea of radio interferometry with a network of radio receivers which are separated by spatial baselines comparable to the wavelength of the observed radio waves, i.e., ~1-100 km which corresponds to a frequency range from ~3-300 kHz. The key parameter towards the realization of the radio interferometer is the frequency dependent slowness of the radio waves within the Earth's atmosphere with respect to the speed of light in vacuum. This slowness is measured with the radio interferometer by using well documented radio transmitters. The digital low frequency radio camera can be operated in different modes. In the imaging mode, still photographs show maps of the low frequency radio sky. In the video mode, movies show the dynamics of the low frequency radio sky. The exposure time of the photograhps, the frame rate of the video, and the radio frequency of interest can be adjusted by the observer. Alternatively, the digital radio camera can be used in the monitoring mode, where a particular area of the sky is observed continuously. The first application of the digital low frequency radio camera is to characterize the electromagnetic energy emanating from sprite producing lightning discharges, but it is expected that it can also be used to identify and investigate numerous other radio sources of the Earth's electromagnetic environment.

  2. Electrical properties of the electroceramic composite in the microwave frequency range: Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} (PFN)-Cr{sub 0.75}Fe{sub 1.25}O{sub 3} (CRFO)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, M R P; Freire, F N A; Sohn, R S T M; Almeida, J S; Sancho, E O; Costa, A D S B; Medeiros, A M L; Sombra, A S B [Laboratorio de Telecomunicacoes e Ciencia e Engenharia dos Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil)], E-mail: sombra@fisica.ufc.br

    2008-12-15

    In this paper, a new electroceramic composite [Pb(Fe{sub 0.5}Nb{sub 0.5}) O{sub 3} (PFN)]{sub Z} [Cr{sub 0.75}Fe{sub 1.25}O{sub 3} (CRFO)]{sub 100-Z} (Z = 0, 10) is investigated in the microwave (MW) frequency range. The dielectric permittivity and loss in the region of 4-8 GHz (G and H MW bands) were studied. The performance of cylindrical resonator antennas based on CRFO100 and on PFN10 was examined. The experimental and theoretical results of the dielectric resonator antenna (DRA) such as return loss, bandwidth, input impedance and radiation patterns are in good agreement for both composites: PFN10 (10% PFN + 90% CRFO) and CRFO100 (100% CRFO). A numerical validation was made considering an air gap between the dielectric resonator and the metallic conductors. The PFN10 matrix composite PFN10 (10% PFN + 90% CRFO) presents the highest dielectric permittivity (9.9 at 4.44 GHz) and the lowest bandwidth (9.9%). The CRFO100 phase (100% CRFO) presents a dielectric permittivity of 8.35 at 4.67 GHz and a bandwidth of 11.8%. The Hakki-Coleman procedure was also used in this study. The dielectric permittivity of 8.35 (tan {delta} = 1 x 10{sup -3}) at 7.94 GHz was obtained for CRFO100. The PFN10 presents a dielectric permittivity of 10.17 (tan {delta} = 4.9 x 10{sup -3}) at 7.05 GHz. These measurements confirm the possible use of such material for small DRAs.

  3. Multiple Frequency Parametric Sonar

    Science.gov (United States)

    2015-09-28

    300003 1 MULTIPLE FREQUENCY PARAMETRIC SONAR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...a method for increasing the bandwidth of a parametric sonar system by using multiple primary frequencies rather than only two primary frequencies...2) Description of Prior Art [0004] Parametric sonar generates narrow beams at low frequencies by projecting sound at two distinct primary

  4. Patterns of endemicity and range restriction among southern African ...

    African Journals Online (AJOL)

    Although the distribution and overall species-richness patterns of several component taxa are well documented, studies considering range sizes are absent. This study considers range size frequencies and distribution patterns of seven major marine invertebrate taxa. The most commonly observed pattern of size frequency ...

  5. Long range image enhancement

    CSIR Research Space (South Africa)

    Duvenhage, B

    2015-11-01

    Full Text Available and Vision Computing, Auckland, New Zealand, 23-24 November 2015 Long Range Image Enhancement Bernardt Duvenhage Council for Scientific and Industrial Research South Africa Email: bduvenhage@csir.co.za Abstract Turbulent pockets of air...

  6. SNOWY RANGE WILDERNESS, WYOMING.

    Science.gov (United States)

    Houston, Robert S.; Bigsby, Philip R.

    1984-01-01

    A mineral survey of the Snowy Range Wilderness in Wyoming was undertaken and was followed up with more detailed geologic and geochemical surveys, culminating in diamond drilling of one hole in the Snowy Range Wilderness. No mineral deposits were identified in the Snowy Range Wilderness, but inasmuch as low-grade uranium and associated gold resources were identified in rocks similar to those of the northern Snowy Range Wilderness in an area about 5 mi northeast of the wilderness boundary, the authors conclude that the northern half of the wilderness has a probable-resource potential for uranium and gold. Closely spaced drilling would be required to completely evaluate this mineral potential. The geologic terrane precludes the occurrence of fossil fuels.

  7. 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...

  8. Light Detection And Ranging

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — LiDAR (Light Detection and Ranging) discrete-return point cloud data are available in the American Society for Photogrammetry and Remote Sensing (ASPRS) LAS format....

  9. On Range of Skill

    DEFF Research Database (Denmark)

    Hansen, Thomas Dueholm; Miltersen, Peter Bro; Sørensen, Troels Bjerre

    2008-01-01

    is a small number, but only gave heuristic arguments for this. In this paper, we provide the first methods for rigorously estimating the Range of Skill of a given game. We provide some general, asymptotic bounds that imply that the Range of Skill of a perfectly balanced game tree is almost exponential in its......At AAAI'07, Zinkevich, Bowling and Burch introduced the Range of Skill measure of a two-player game and used it as a parameter in the analysis of the running time of an algorithm for finding approximate solutions to such games. They suggested that the Range of Skill of a typical natural game...... 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...

  10. 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

  11. Integrating local ecological knowledge and management practices of an isolated semi-arid papyrus swamp (Loboi, Kenya) into a wider conservation framework.

    Science.gov (United States)

    Terer, Taita; Muasya, A Muthama; Dahdouh-Guebas, Farid; Ndiritu, George G; Triest, Ludwig

    2012-01-01

    The current study documented local utilization of Cyperus papyrus L. (papyrus), harvesting patterns, threats, and local management practices among the Endorois community living around Loboi swamp (Kenya). Papyrus is a highly productive freshwater macrophyte that is widely utilized throughout tropical Africa. However, increased human population and poverty, has led to over exploitation and conversion of papyrus wetlands to agricultural fields. Nonetheless, users of papyrus hold important local ecological knowledge (LEK) and practices. We show that Endorois practices on papyrus uses are compatible with the management priorities of the swamp and a wider conservation framework using data obtained from three focus group discussions (FGD), interviews of 34 households and 15 key informants. The study revealed that papyrus support local livelihood notably as a source of income (papyrus mats are sold), cattle fodder, roofing materials (shelter), and cooking fuel. The study further revealed important LEK relating to harvesting patterns, recovery after harvesting and traditional management practices. Correlation and principal component analyses showed that experienced old harvesters (EXPERT) avoided harvesting repeatedly at the same location (REVISIT), thereby allowing recovery of papyrus when compared to younger harvesters (r = 0.63, p papyrus coverage in the future due to the current diversion of water from the swamp, and frequent droughts, despite the instituted traditional management strategies (e.g. rotational harvesting) to curb overharvesting. The study concluded that the documentation of site-scale papyrus users' profile, LEK, and traditional practices are vital for the conservation and management of Loboi swamp. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. The older, the wider: On-field tactical behavior of elite-standard youth soccer players in small-sided games.

    Science.gov (United States)

    Olthof, Sigrid B H; Frencken, Wouter G P; Lemmink, Koen A P M

    2015-06-01

    Young soccer players need excellent tactical skills to reach the top. Tactical behavior emerges through interactions between opposing teams. However, few studies have focused on on-field tactical behavior of teams with talented soccer players. Therefore, this study aimed to determine teams' tactical behavior during small-sided games in two age categories, Under-17 and Under-19. Positional data of thirty-nine elite-standard soccer players were collected during twenty-four small-sided games to calculate longitudinal and lateral inter-team distances, stretch indices and length per width ratios. Corresponding interaction patterns and game-to-game variability were also determined. Under-19 showed a significantly larger lateral stretch index and a significantly lower length per width ratio compared with Under-17. Furthermore, teams of both age groups showed similar large proportions of in-phase behavior. Variability of tactical performance measures within and between games was similar for Under-17 and Under-19. Variability within games seems to be functional for attacking teams for creating goal-scoring opportunities. In conclusion, the main difference was that Under-19 adopted a wider pitch dispersion than Under-17, represented by a larger lateral stretch index and smaller length per width ratio. Coach instructions and training exercises should be directed at exploiting pitch width to increase the pursuit of goal-scoring. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Crafting a Wider Strategy for Conflict Management in the Neighbourhood? A Comparative Perspective on the European Union’s Civilian Missions in Georgia and Kosovo

    Directory of Open Access Journals (Sweden)

    Monica Oproiu

    2015-06-01

    Full Text Available The European Union’s wider neighbourhood hosts some of the world’s main unresolved conflicts. As the EU developed its foreign and security policy, a blend of internal security and external stability concerns, as well as the reference to international legal and humanitarian norms, required it to try tackling (some of these conflicts. Through both the European Neighbourhood Policy and the Stabilisation and Association Process the EU establishes contractual relations with its neighbours and tries to incentivise them for the adoption of economic and political reforms and legislative approximation to EU standards. Also, in some cases, the EU is providing support for conflict management through political dialogue, financial assistance or deployment of missions under the Common Security and Defence Policy. At its core, this paper is concerned with comparatively analysing the degree of integration between CSDP and the ENP and SAP frameworks respectively. The comparative case-study will therefore analyse CSDP missions undertaken in the Georgia/ Abkhazia and South Ossetia and Kosovo/Serbia cases, in order to identify common challenges across the two EU policy frameworks for its neighbourhood and to explore the perspectives for the emergence of an EU strategy of conflict management based on CSDP operations and various forms of engaging third countries.

  14. The pursuit of a remedy for gender inequality in wider Europe: Comparison of policies and indices in the EU, Nordic countries, and south east Europe

    Directory of Open Access Journals (Sweden)

    Kovačević Jasna

    2015-01-01

    Full Text Available This paper explores the differences between gender regimes in Europe, with an emphasis on EU policies, the Nordic women-friendly welfare states, and the former socialist policies of South Eastern European (SEE countries. The main premise is that culture and differing institutionalization of gender equality contribute to different perceptions of women’s role in society and to a different perception of gender equality in general. The paper examines the theoretical standpoints and historical background of different gender regimes in Europe. Gender equality indices are analyzed in order to investigate if any patterns exist among European countries with distinct cultural, political, and social backgrounds. Nordic countries are overachievers in gender equality in Europe, mainly due to the prevailing egalitarianism and institutionalization of women-friendly welfare policies, which can serve as a good benchmark for wider Europe, especially for countries from South East Europe. However, cultural differences exist between Scandinavian and other European countries, which cannot be considered homogeneous. The paper raises important issues of gender equality such as multiculturalism and immigration, questioning to what extent future EU enlargements will increase the risk of greater gender inequality in the EU.

  15. Semi-open environmental conditions during phases of hominin occupation at the Eemian Interglacial basin site Neumark-Nord 2 and its wider environment

    Science.gov (United States)

    Pop, Eduard; Bakels, Corrie

    2015-06-01

    Neandertal occupation of Eemian environments in Europe is well attested by several archaeological sites dating to this interglacial period. Does this mean that Neandertals were living in closed forest environments? Due to the potential variability of Eemian environments in space and time, it is necessary to study environmental records that can be correlated with phases of hominin presence, as reflected in the archaeological record. Such a perspective can be obtained from the small basin locality Neumark-Nord 2, as it contains an extensive and detailed environmental record, as well as a large archaeological record consisting of several distinct find levels. Analysis shows that hominin presence is predominantly associated with semi-open environmental conditions. A review of the data from the neighbouring Neumark-Nord 1 basin shows that semi-open environments were also characterizing the wider environment during phases of hominin presence at both basin localities. Large herbivores attracted to the water in these basins may have played an important role in the vegetation openness, probably in conjunction with (local) climatic conditions. The relationship between hominin presence and semi-open environments is explained as Neandertals exploiting the large herbivores aggregating around these freshwater localities, while the more varied vegetation would also have provided them with edible plant foods. Other Eemian sites from freshwater contexts provide evidence for semi-open conditions as well.

  16. Theoretical detection threshold of the proton-acoustic range verification technique

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Moiz; Yousefi, Siavash; Xing, Lei, E-mail: lei@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305-5847 (United States); Xiang, Liangzhong [Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019-1101 (United States)

    2015-10-15

    Purpose: Range verification in proton therapy using the proton-acoustic signal induced in the Bragg peak was investigated for typical clinical scenarios. The signal generation and detection processes were simulated in order to determine the signal-to-noise limits. Methods: An analytical model was used to calculate the dose distribution and local pressure rise (per proton) for beams of different energy (100 and 160 MeV) and spot widths (1, 5, and 10 mm) in a water phantom. In this method, the acoustic waves propagating from the Bragg peak were generated by the general 3D pressure wave equation implemented using a finite element method. Various beam pulse widths (0.1–10 μs) were simulated by convolving the acoustic waves with Gaussian kernels. A realistic PZT ultrasound transducer (5 cm diameter) was simulated with a Butterworth bandpass filter with consideration of random noise based on a model of thermal noise in the transducer. The signal-to-noise ratio on a per-proton basis was calculated, determining the minimum number of protons required to generate a detectable pulse. The maximum spatial resolution of the proton-acoustic imaging modality was also estimated from the signal spectrum. Results: The calculated noise in the transducer was 12–28 mPa, depending on the transducer central frequency (70–380 kHz). The minimum number of protons detectable by the technique was on the order of 3–30 × 10{sup 6} per pulse, with 30–800 mGy dose per pulse at the Bragg peak. Wider pulses produced signal with lower acoustic frequencies, with 10 μs pulses producing signals with frequency less than 100 kHz. Conclusions: The proton-acoustic process was simulated using a realistic model and the minimal detection limit was established for proton-acoustic range validation. These limits correspond to a best case scenario with a single large detector with no losses and detector thermal noise as the sensitivity limiting factor. Our study indicated practical proton

  17. Theoretical detection threshold of the proton-acoustic range verification technique.

    Science.gov (United States)

    Ahmad, Moiz; Xiang, Liangzhong; Yousefi, Siavash; Xing, Lei

    2015-10-01

    Range verification in proton therapy using the proton-acoustic signal induced in the Bragg peak was investigated for typical clinical scenarios. The signal generation and detection processes were simulated in order to determine the signal-to-noise limits. An analytical model was used to calculate the dose distribution and local pressure rise (per proton) for beams of different energy (100 and 160 MeV) and spot widths (1, 5, and 10 mm) in a water phantom. In this method, the acoustic waves propagating from the Bragg peak were generated by the general 3D pressure wave equation implemented using a finite element method. Various beam pulse widths (0.1-10 μs) were simulated by convolving the acoustic waves with Gaussian kernels. A realistic PZT ultrasound transducer (5 cm diameter) was simulated with a Butterworth bandpass filter with consideration of random noise based on a model of thermal noise in the transducer. The signal-to-noise ratio on a per-proton basis was calculated, determining the minimum number of protons required to generate a detectable pulse. The maximum spatial resolution of the proton-acoustic imaging modality was also estimated from the signal spectrum. The calculated noise in the transducer was 12-28 mPa, depending on the transducer central frequency (70-380 kHz). The minimum number of protons detectable by the technique was on the order of 3-30 × 10(6) per pulse, with 30-800 mGy dose per pulse at the Bragg peak. Wider pulses produced signal with lower acoustic frequencies, with 10 μs pulses producing signals with frequency less than 100 kHz. The proton-acoustic process was simulated using a realistic model and the minimal detection limit was established for proton-acoustic range validation. These limits correspond to a best case scenario with a single large detector with no losses and detector thermal noise as the sensitivity limiting factor. Our study indicated practical proton-acoustic range verification may be feasible with approximately 5

  18. Decameter Type III Bursts with Changing Frequency Drift-Rate Signs

    Science.gov (United States)

    Melnik, V. N.; Brazhenko, A. I.; Konovalenko, A. A.; Briand, C.; Dorovskyy, V. V.; Zarka, P.; Frantsuzenko, A. V.; Rucker, H. O.; Rutkevych, B. P.; Panchenko, M.; Denis, L.; Zaqarashvili, T.; Shergelashvili, B.

    2015-01-01

    We discuss properties of type III bursts that change the sign of their drift rate from negative to positive and vice versa. Moreover, these bursts may change the sign of their drift rates more than once. These particular type III bursts were observed simultaneously by the radio telescopes UTR-2 ( Ukrainian T-shaped Radio telescope, Kharkov, Ukraine), URAN-2 ( Ukrainian Radio telescope of the Academy of Sciences, Poltava, Ukraine), and by the NDA ( Nançay Decametric Array, Nancay, France) in the frequency range 8 - 41 MHz. The negative drift rates of these bursts are similar to those of previously reported decameter type III bursts and vary from -0.7 MHz s-1 to -1.7 MHz s-1, but their positive drift rates vary in a wider range from 0.44 MHz s-1 to 6 MHz s-1. Unlike inverted U-bursts, the tracks of these type III bursts have C- or inverted C-shapes.

  19. LOFAR: The LOw-Frequency ARray

    NARCIS (Netherlands)

    van Haarlem, M. P.; Wise, M. W.; Gunst, A. W.; Heald, G.; McKean, J. P.; Hessels, J. W. T.; de Bruyn, A. G.; Nijboer, R.; Swinbank, J.; Fallows, R.; Brentjens, M.; Nelles, A.; Beck, R.; Falcke, H.; Fender, R.; Hörandel, J.; Koopmans, L. V. E.; Mann, G.; Miley, G.; Röttgering, H.; Stappers, B. W.; Wijers, R. A. M. J.; Zaroubi, S.; van den Akker, M.; Alexov, A.; Anderson, J.; Anderson, K.; van Ardenne, A.; Arts, M.; Asgekar, A.; Avruch, I. M.; Batejat, F.; Bähren, L.; Bell, M. E.; Bell, M. R.; van Bemmel, I.; Bennema, P.; Bentum, M. J.; Bernardi, G.; Best, P.; Bîrzan, L.; Bonafede, A.; Boonstra, A.-J.; Braun, R.; Bregman, J.; Breitling, F.; van de Brink, R. H.; Broderick, J.; Broekema, P. C.; Brouw, W. N.; Brüggen, M.; Butcher, H. R.; van Cappellen, W.; Ciardi, B.; Coenen, T.; Conway, J.; Coolen, A.; Corstanje, A.; Damstra, S.; Davies, O.; Deller, A. T.; Dettmar, R.-J.; van Diepen, G.; Dijkstra, K.; Donker, P.; Doorduin, A.; Dromer, J.; Drost, M.; van Duin, A.; Eislöffel, J.; van Enst, J.; Ferrari, C.; Frieswijk, W.; Gankema, H.; Garrett, M. A.; de Gasperin, F.; Gerbers, M.; de Geus, E.; Grießmeier, J.-M.; Grit, T.; Gruppen, P.; Hamaker, J. P.; Hassall, T.; Hoeft, M.; Holties, H. A.; Horneffer, A.; van der Horst, A.; van Houwelingen, A.; Huijgen, A.; Iacobelli, M.; Intema, H.; Jackson, N.; Jelic, V.; de Jong, A.; Juette, E.; Kant, D.; Karastergiou, A.; Koers, A.; Kollen, H.; Kondratiev, V. I.; Kooistra, E.; Koopman, Y.; Koster, A.; Kuniyoshi, M.; Kramer, M.; Kuper, G.; Lambropoulos, P.; Law, C.; van Leeuwen, J.; Lemaitre, J.; Loose, M.; Maat, P.; Macario, G.; Markoff, S.; Masters, J.; McFadden, R. A.; McKay-Bukowski, D.; Meijering, H.; Meulman, H.; Mevius, M.; Middelberg, E.; Millenaar, R.; Miller-Jones, J. C. A.; Mohan, R. N.; Mol, J. D.; Morawietz, J.; Morganti, R.; Mulcahy, D. D.; Mulder, E.; Munk, H.; Nieuwenhuis, L.; van Nieuwpoort, R.; Noordam, J. E.; Norden, M.; Noutsos, A.; Offringa, A. R.; Olofsson, H.; Omar, A.; Orrú, E.; Overeem, R.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pizzo, R.; Polatidis, A.; Rafferty, D.; Rawlings, S.; Reich, W.; de Reijer, J.-P.; Reitsma, J.; Renting, G. A.; Riemers, P.; Rol, E.; Romein, J. W.; Roosjen, J.; Ruiter, M.; Scaife, A.; van der Schaaf, K.; Scheers, B.; Schellart, P.; Schoenmakers, A.; Schoonderbeek, G.; Serylak, M.; Shulevski, A.; Sluman, J.; Smirnov, O.; Sobey, C.; Spreeuw, H.; Steinmetz, M.; Sterks, C. G. M.; Stiepel, H.-J.; Stuurwold, K.; Tagger, M.; Tang, Y.; Tasse, C.; Thomas, I.; Thoudam, S.; Toribio, M. C.; van der Tol, B.; Usov, O.; van Veelen, M.; van der Veen, A.-J.; ter Veen, S.; Verbiest, J. P. W.; Vermeulen, R.; Vermaas, N.; Vocks, C.; Vogt, C.; de Vos, M.; van der Wal, E.; van Weeren, R.; Weggemans, H.; Weltevrede, P.; White, S.; Wijnholds, S. J.; Wilhelmsson, T.; Wucknitz, O.; Yatawatta, S.; Zarka, P.; Zensus, A.; van Zwieten, J.

    LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10-240 MHz and provides a number of unique observing

  20. LOFAR : The LOw-Frequency ARray

    NARCIS (Netherlands)

    van Haarlem, M. P.; Wise, M. W.; Gunst, A. W.; Heald, G.; McKean, J. P.; Hessels, J. W. T.; de Bruyn, A. G.; Nijboer, R.; Swinbank, J.; Fallows, R.; Brentjens, M.; Nelles, A.; Beck, R.; Falcke, H.; Fender, R.; Horandel, J.; Koopmans, L. V. E.; Mann, G.; Miley, G.; Rottgering, H.; Stappers, B. W.; Wijers, R. A. M. J.; Zaroubi, S.; van den Akker, M.; Alexov, A.; Anderson, J.; Anderson, K.; van Ardenne, A.; Arts, M.; Asgekar, A.; Avruch, I. M.; Batejat, F.; Bahren, L.; Bell, M. E.; Bell, M. R.; van Bemmel, I.; Bennema, P.; Bentum, M. J.; Bernardi, G.; Best, P.; Birzan, L.; Bonafede, A.; Boonstra, A. -J.; Braun, R.; Bregman, J.; Breitling, F.; van de Brink, R. H.; Broderick, J.; Broekema, P. C.; Brouw, W. N.; Brueggen, M.; Butcher, H. R.; van Cappellen, W.; Ciardi, B.; Coenen, T.; Conway, J.; Coolen, A.; Corstanje, A.; Damstra, S.; Davies, O.; Deller, A. T.; Dettmar, R. -J.; van Diepen, G.; Dijkstra, K.; Donker, P.; Doorduin, A.; Dromer, J.; Drost, M.; van Duin, A.; Eisloeffel, J.; van Enst, J.; Ferrari, C.; Frieswijk, W.; Gankema, H.; Garrett, M. A.; de Gasparin, F.; Gerbers, M.; de Geus, E.; Griessmeier, J. -M.; Grit, T.; Gruppen, P.; Hamaker, J. P.; Hassall, T.; Hoeft, M.; Holties, H. A.; Horneffer, A.; van der Horst, A.; van Houwelingen, A.; Huijgen, A.; Iacobelli, M.; Intema, H.; Jackson, N.; Jelic, V.; de Jong, A.; Kant, D.; Karastergiou, A.; Koers, A.; Kollen, H.; Kondratiev, V. I.; Koopman, Y.; Koster, A.; Kuniyoshi, M.; Kramer, M.; Kuper, G.; Lambropoulos, P.; Law, C.; van Leeuwen, J.; Lemaitre, J.; Loose, M.; Maat, P.; Macario, G.; Markoff, S.; Masters, J.; McFadden, R. A.; McKay-Bukowski, D.; Meijering, H.; Meulman, H.; Mevius, M.; Millenaar, R.; Miller-Jones, J. C. A.; Mohan, R. N.; Mol, J.D.; Morawietz, J.; Morganti, R.; Mulcahy, D. D.; Mulder, E.; Munk, H.; Nieuwenhuis, L.; van Nieuwpoort, R.; Noordam, J. E.; Norden, M.; Noutsos, A.; Offringa, A. R.; Olofsson, H.; Omar, A.; Orru, E.; Overeem, R.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pizzo, R.; Polatidis, A.; Rafferty, D.; Rawlings, S.; Reich, W.; de Reijer, J. -P.; Reitsma, J.; Renting, G. A.; Riemers, P.; Rol, E.; Romein, J. W.; Roosjen, J.; Ruiter, M.; Scaife, A.; van der Schaaf, K.; Scheers, B.; Schellart, P.; Schoenmakers, A.; Schoonderbeek, G.; Serylak, M.; Shulevski, A.; Sluman, J.; Smirnov, O.; Sobey, C.; Spreeuw, H.; Steinmetz, M.; Sterks, C. G. M.; Stiepel, H. -J.; Stuurwold, K.; Tagger, M.; Tang, Y.; Tasse, C.; Thomas, I.; Thoudam, S.; Toribio, M. C.; van der Tol, B.; Usov, O.; van Veelen, M.; van der Veen, A. -J.; ter Veen, S.; Verbiest, J. P. W.; Vermeulen, R.; Vermaas, N.; Vocks, C.; Vogt, C.; de Vos, M.; van der Wal, E.; van Weeren, R.; Weggemans, H.; Weltevrede, P.; White, S.; Wijnholds, S. J.; Wilhelmsson, T.; Wucknitz, O.; Yatawatta, S.; Zarka, P.; Zensus, A.; van Zwieten, J.; Kooistra, E.

    LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10-240 MHz and provides a number of unique observing

  1. Tsunami Arrival Detection with High Frequency (HF Radar

    Directory of Open Access Journals (Sweden)

    Donald Barrick

    2012-05-01

    Full Text Available Quantitative real-time observations of a tsunami have been limited to deep-water, pressure-sensor observations of changes in the sea surface elevation and observations of sea level fluctuations at the coast, which are essentially point measurements. Constrained by these data, models have been used for predictions and warning of the arrival of a tsunami, but to date no system exists for local detection of an actual incoming wave with a significant warning capability. Networks of coastal high frequency (HF-radars are now routinely observing surface currents in many countries. We report here on an empirical method for the detection of the initial arrival of a tsunami, and demonstrate its use with results from data measured by fourteen HF radar sites in Japan and USA following the magnitude 9.0 earthquake off Sendai, Japan, on 11 March 2011. The distance offshore at which the tsunami can be detected, and hence the warning time provided, depends on the bathymetry: the wider the shallow continental shelf, the greater this time. We compare arrival times at the radars with those measured by neighboring tide gauges. Arrival times measured by the radars preceded those at neighboring tide gauges by an average of 19 min (Japan and 15 min (USA The initial water-height increase due to the tsunami as measured by the tide gauges was moderate, ranging from 0.3 to 2 m. Thus it appears possible to detect even moderate tsunamis using this method. Larger tsunamis could obviously be detected further from the coast. We find that tsunami arrival within the radar coverage area can be announced 8 min (i.e., twice the radar spectral time resolution after its first appearance. This can provide advance warning of the tsunami approach to the coastline locations.

  2. Frequency dependence of lung volume changes during superimposed high-frequency jet ventilation and high-frequency jet ventilation.

    Science.gov (United States)

    Sütterlin, R; Priori, R; Larsson, A; LoMauro, A; Frykholm, P; Aliverti, A

    2014-01-01

    Superimposed high-frequency jet ventilation (SHFJV) has proved to be safe and effective in clinical practice. However, it is unclear which frequency range optimizes ventilation and gas exchange. The aim of this study was to systematically compare high-frequency jet ventilation (HFJV) with HFJV by assessing chest wall volume variations (ΔEEV(CW)) and gas exchange in relation to variable high frequency. SHFJV or HFJV were used alternatively to ventilate the lungs of 10 anaesthetized pigs (21-25 kg). The low-frequency component was kept at 16 min(-1) in SHFJV. In both modes, high frequencies ranging from 100 to 1000 min(-1) were applied in random order and ventilation was maintained for 5 min in all modalities. Chest wall volume variations were obtained using opto-electronic plethysmography. Airway pressures and arterial blood gases were measured repeatedly. SHFJV increased ΔEEV(CW) compared with HFJV; the difference ranged from 43 to 68 ml. Tidal volume (V(T)) was always >240 ml during SHFJV whereas during HFJV ranged from 92 ml at the ventilation frequency of 100 min(-1) to negligible values at frequencies >300 min(-1). We observed similar patterns for Pa(O₂) and Pa(CO₂). SHFJV provided generally higher, frequency-independent oxygenation (Pa(O₂) at least 32.0 kPa) and CO₂ removal (Pa(CO₂) ∼5.5 kPa), whereas HFJV led to hypoxia and hypercarbia at higher rates (Pa(O₂) 10 kPa at f(HF)>300 min(-1)). In a porcine model, SHFJV was more effective in increasing end-expiratory volume than single-frequency HFJV, but both modes may provide adequate ventilation in the absence of airway obstruction and respiratory disease, except for HFJV at frequencies ≥300 min(-1).

  3. 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 < 0.05). On average, daily frequency and duration of 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 < 0.01) and pop-holes were favoured (p < 0.05). We provide evidence of relationships between ranging and external factors that may explain ranging preferences.

  4. Magnitude-frequency of sea cliff instabilities

    Directory of Open Access Journals (Sweden)

    F. M. S. F. Marques

    2008-10-01

    Full Text Available The magnitude-frequency relationship of sea cliff failures in strong, low retreat rate cliffs, was studied using systematic historical inventories carried out in the coasts of Portugal and Morocco, in different geological and geomorphological settings, covering a wide size scale, from small to comparatively large rockslides, topples and rockfalls, at different time and spatial scales. The magnitude-frequency expressed in terms of volume displaced and of horizontal area lost at the cliff top showed good fit by inverse power laws of the type p=a.x−b, with a values from 0.2 to 0.3, and exponents b close to 1.0, similar to those proposed for rockfall inventories. The proposed power laws address the magnitude-frequency for sea cliff failures, which is an important component of hazard assessment, to be completed with adequate models for space and time hazard components. Maximum local retreat at the cliff top provided acceptable fitting to inverse power laws only for failures wider than 2m, with a = 4.0, and exponent b = 2.3, which may be useful to assess the cliff retreat hazard for the use of areas located near the cliff top.

  5. Psychophysical tuning curves for very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Moore, Brian C.J.; Pedersen, Christian Sejer

    2010-01-01

    Prediction and assessment of problems produced by low-frequency noise requires information about frequency selectivity in the low-frequency range. However, there are few data on frequency selectivity for centre frequencies below 100 Hz. To estimate the characteristics of auditory tuning for very...... low frequencies, psychophysical tuning curves (PTCs) were obtained for centre frequencies of 31.5, 40, and 50 Hz. An equal-loudness-level contour was also obtained using closely spaced frequencies. This was used as a rough estimate of the shape of the individual middle-ear transfer function...

  6. Range Selection and Median

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund; Larsen, Kasper Green

    2011-01-01

    that supports queries in constant time, needs n1+ (1) space. For data structures that uses n logO(1) n space this matches the best known upper bound. Additionally, we present a linear space data structure that supports range selection queries in O(log k= log log n + log log n) time. Finally, we prove that any...

  7. Electric vehicles: Driving range

    Science.gov (United States)

    Kempton, Willett

    2016-09-01

    For uptake of electric vehicles to increase, consumers' driving-range needs must be fulfilled. Analysis of the driving patterns of personal vehicles in the US now shows that today's electric vehicles can meet all travel needs on almost 90% of days from a single overnight charge.

  8. Physical exam frequency

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002125.htm Physical exam frequency To use the sharing features on this page, ... screening; Checkup Images Blood pressure check Physical exam frequency References Atkins D, Barton M. The periodic health ...

  9. 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

  10. Frequency reference in VSAT

    Science.gov (United States)

    Cheah, Jonathon Y. C.

    1994-02-01

    A low cost technique of frequency reference distribution within a VSAT network is discussed. This technique allows the use of a modestly frequency stable oscillator as the master frequency reference in the hub of a star-connected VSAT network. The need for extremely frequency stable OCXOs in VSATs is completely avoided. This technique was successfully incorporated in the early commercial VSAT networks. It contributes partially to the low cost nature of some of the VSAT networks available today.

  11. Modeling Frequency Comb Sources

    Directory of Open Access Journals (Sweden)

    Li Feng

    2016-06-01

    Full Text Available Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  12. Making Sense of Frequency.

    Science.gov (United States)

    Larsen-Freeman, Diane

    2002-01-01

    Responds to Ellis (2002), which focuses on frequency in language processing, language use, and language acquisition. Contextualizes the frequency factor in terms of the evolution of second language acquisition (SLA) research. Suggests that although relevant and important, the frequency factor requires greater definition and qualification.…

  13. Cover/Frequency (CF)

    Science.gov (United States)

    John F. Caratti

    2006-01-01

    The FIREMON Cover/Frequency (CF) method is used to assess changes in plant species cover and frequency for a macroplot. This method uses multiple quadrats to sample within-plot variation and quantify statistically valid changes in plant species cover, height, and frequency over time. Because it is difficult to estimate cover in quadrats for larger plants, this method...

  14. 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.

  15. The frequency polygon reconsidered.

    NARCIS (Netherlands)

    van Casteren, P.H.F.M.

    1997-01-01

    The frequency polygon is not compatible with the given frequency distribution in the sense that the areas within the classes are not proportional to the frequencies. As a consequence, the polygon is too flat. Therefore, an alternative polygon is constructed as a continuous version of the histogram

  16. Broadband frequency conversion

    DEFF Research Database (Denmark)

    Sanders, Nicolai Højer; Jensen, Ole Bjarlin; Dam, Jeppe Seidelin

    We demonstrate a method for frequency conversion of broadly tunable or broad bandwidth light in a static, passive setup. Using simple optical components like lenses, mirrors and gratings and a BiBO crystal as the nonlinear material, we are able to frequency double a single-frequency, tunable...

  17. Flexible alternatives to constant frequency systems

    Science.gov (United States)

    Stewart-Wilson, John

    The use of hybrid systems in which variable frequency is used as generated, with a proportion being converted to constant frequency by electronic conversion, is examined as a flexible alternative to constant frequency systems. Here, some practical solutions to the technical issues raised by adopting the more flexible approach to electrical system generation are presented. In particular, attention is given to the frequency ranges used, impact on aircraft equipment, motor-driven equipment, transformer rectifier units, lighting, and avionics. The discussion also covers fan-assisted galley ovens, system architecture, special airworthiness requirements, and power quality.

  18. Frequency selective infrared sensors

    Science.gov (United States)

    Davids, Paul; Peters, David W

    2013-05-28

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  19. Radio frequency spectrum management

    Science.gov (United States)

    Sujdak, E. J., Jr.

    1980-03-01

    This thesis is a study of radio frequency spectrum management as practiced by agencies and departments of the Federal Government. After a brief introduction to the international agency involved in radio frequency spectrum management, the author concentrates on Federal agencies engaged in frequency management. These agencies include the National Telecommunications and Information Administration (NTIA), the Interdepartment Radio Advisory Committee (IRAC), and the Department of Defense (DoD). Based on an analysis of Department of Defense frequency assignment procedures, recommendations are given concerning decentralizing military frequency assignment by delegating broader authority to unified commanders. This proposal includes a recommendation to colocate the individual Service frequency management offices at the Washington level. This would result in reduced travel costs, lower manpower requirements, and a common tri-Service frequency management data base.

  20. 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.

  1. Online Sorted Range Reporting

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf; Greve, Mark

    2009-01-01

    We study the following one-dimensional range reporting problem: On an arrayA of n elements, support queries that given two indices i ≤ j and an integerk report the k smallest elements in the subarray A[i..j] in sorted order. We present a data structure in the RAM model supporting such queries...... in optimal O(k) time. The structure uses O(n) words of space and can be constructed in O(n logn) time. The data structure can be extended to solve the online version of the problem, where the elements in A[i..j] are reported one-by-one in sorted order, in O(1) worst-case time per element. The problem...... 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....

  2. Frequency response of vestibular reflexes in neck, back, and lower limb muscles.

    Science.gov (United States)

    Forbes, Patrick A; Dakin, Christopher J; Vardy, Alistair N; Happee, Riender; Siegmund, Gunter P; Schouten, Alfred C; Blouin, Jean-Sébastien

    2013-10-01

    Vestibular pathways form short-latency disynaptic connections with neck motoneurons, whereas they form longer-latency disynaptic and polysynaptic connections with lower limb motoneurons. We quantified frequency responses of vestibular reflexes in neck, back, and lower limb muscles to explain between-muscle differences. Two hypotheses were evaluated: 1) that muscle-specific motor-unit properties influence the bandwidth of vestibular reflexes; and 2) that frequency responses of vestibular reflexes differ between neck, back, and lower limb muscles because of neural filtering. Subjects were exposed to electrical vestibular stimuli over bandwidths of 0-25 and 0-75 Hz while recording activity in sternocleidomastoid, splenius capitis, erector spinae, soleus, and medial gastrocnemius muscles. Coherence between stimulus and muscle activity revealed markedly larger vestibular reflex bandwidths in neck muscles (0-70 Hz) than back (0-15 Hz) or lower limb muscles (0-20 Hz). In addition, vestibular reflexes in back and lower limb muscles undergo low-pass filtering compared with neck-muscle responses, which span a broader dynamic range. These results suggest that the wider bandwidth of head-neck biomechanics requires a vestibular influence on neck-muscle activation across a larger dynamic range than lower limb muscles. A computational model of vestibular afferents and a motoneuron pool indicates that motor-unit properties are not primary contributors to the bandwidth filtering of vestibular reflexes in different muscles. Instead, our experimental findings suggest that pathway-dependent neural filtering, not captured in our model, contributes to these muscle-specific responses. Furthermore, gain-phase discontinuities in the neck-muscle vestibular reflexes provide evidence of destructive interaction between different reflex components, likely via indirect vestibular-motor pathways.

  3. Lightning detection and ranging

    Science.gov (United States)

    Lennon, C. L.; Poehler, H. A.

    1982-01-01

    A lightning detector and ranging (LDAR) system developed at the Kennedy Space Center and recently transferred to Wallops Island is described. The system detects pulsed VHF signals due to electrical discharges occurring in a thunderstorm by means of 56-75 MHz receivers located at the hub and at the tips of 8 km radial lines. Incoming signals are transmitted by wideband links to a central computing facility which processes the times of arrival, using two independent calculations to determine position in order to guard against false data. The results are plotted on a CRT display, and an example of a thunderstorm lightning strike detection near Kennedy Space Center is outlined. The LDAR correctly identified potential ground strike zones and additionally provided a high correlation between updrafts and ground strikes.

  4. Comparison of range migration correction algorithms for range-Doppler processing

    Science.gov (United States)

    Uysal, Faruk

    2017-07-01

    The next generation digital radars are able to provide high-range resolution by the advancement of radar hardware technologies. These systems take advantage of coherent integration and Doppler processing technique to increase the target's signal-to-noise ratio. Due to the high-range resolution (small range cells) and fast target motion, a target migrates through multiple range cells within a coherent processing interval. Range cell migration (also known as range walk) occurs and degrades the coherent integration gain. There are many approaches in the literature to correct these unavoidable effects and focus the target in the range-Doppler domain. We demonstrate some of these methods on an operational frequency-modulated continuous-wave (FMCW) radar and point out practical issues in the application.

  5. Radio frequency detection assembly and method for detecting radio frequencies

    Science.gov (United States)

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  6. Across-frequency behavioral estimates of the contribution of inner and outer hair cell dysfunction to individualized audiometric loss.

    Science.gov (United States)

    Johannesen, Peter T; Pérez-González, Patricia; Lopez-Poveda, Enrique A

    2014-01-01

    Identifying the multiple contributors to the audiometric loss of a hearing impaired (HI) listener at a particular frequency is becoming gradually more useful as new treatments are developed. Here, we infer the contribution of inner (IHC) and outer hair cell (OHC) dysfunction to the total audiometric loss in a sample of 68 hearing aid candidates with mild-to-severe sensorineural hearing loss, and for test frequencies of 0.5, 1, 2, 4, and 6 kHz. It was assumed that the audiometric loss (HLTOTAL) at each test frequency was due to a combination of cochlear gain loss, or OHC dysfunction (HLOHC), and inefficient IHC processes (HLIHC), all of them in decibels. HLOHC and HLIHC were estimated from cochlear I/O curves inferred psychoacoustically using the temporal masking curve (TMC) method. 325 I/O curves were measured and 59% of them showed a compression threshold (CT). The analysis of these I/O curves suggests that (1) HLOHC and HLIHC account on average for 60-70 and 30-40% of HLTOTAL, respectively; (2) these percentages are roughly constant across frequencies; (3) across-listener variability is large; (4) residual cochlear gain is negatively correlated with hearing loss while residual compression is not correlated with hearing loss. Altogether, the present results support the conclusions from earlier studies and extend them to a wider range of test frequencies and hearing-loss ranges. Twenty-four percent of I/O curves were linear and suggested total cochlear gain loss. The number of linear I/O curves increased gradually with increasing frequency. The remaining 17% I/O curves suggested audiometric losses due mostly to IHC dysfunction and were more frequent at low (≤1 kHz) than at high frequencies. It is argued that in a majority of listeners, hearing loss is due to a common mechanism that concomitantly alters IHC and OHC function and that IHC processes may be more labile in the apex than in the base.

  7. Across-frequency behavioral estimates of the contribution of inner and outer hair cell dysfunction to individualized audiometric loss

    Directory of Open Access Journals (Sweden)

    Peter T. Johannesen

    2014-07-01

    Full Text Available Identifying the multiple contributors to the audiometric loss of a hearing impaired listener at a particular frequency is becoming gradually more useful as new treatments are developed. Here, we infer the contribution of inner (IHC and outer hair cell (OHC dysfunction to the total audiometric loss in a sample of 68 hearing aid candidates with mild-to-severe sensorineural hearing loss, and for test frequencies of 0.5, 1, 2, 4, and 6 kHz. It was assumed that the audiometric loss (HL_TOTAL at each test frequency was due to a combination of cochlear gain loss, or OHC dysfunction (HL_OHC, and inefficient IHC processes (HL_IHC, all of them in decibels. HL_OHC and HL_IHC were estimated from cochlear I/O curves inferred psychoacoustically using the temporal masking curve method. 325 I/O curves were measured and 59% of them showed a compression threshold. The analysis of these I/O curves suggests that (1 HL_OHC and HL_IHC account on average for 60-70% and 40-30% of HL_TOTAL, respectively; (2 these percentages are roughly constant across frequencies; (3 across-listener variability is large; (4 residual cochlear gain is negatively correlated with hearing loss while residual compression is not correlated with hearing loss. Altogether, the present results support the conclusions from earlier studies and extend them to a wider range of test frequencies and hearing loss ranges. 24% of I/O curves were linear and suggested total cochlear gain loss. The number of linear I/O curves increased gradually with increasing frequency. The remaining 17% I/O curves suggested audiometric losses due mostly to IHC dysfunction and were more frequent at low (≤ 1 kHz than at high frequencies. It is argued that in a majority of listeners, hearing loss is due to a common mechanism that concomitantly alters IHC and OHC function and that IHC processes may be more labile in the apex than in the base.

  8. Waveform frequency notching

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W.; Andrews, John

    2017-05-09

    The various technologies presented herein relate to incorporating one or more notches into a radar spectrum, whereby the notches relate to one or more frequencies for which no radar transmission is to occur. An instantaneous frequency is monitored and if the frequency is determined to be of a restricted frequency, then a radar signal can be modified. Modification can include replacing the signal with a signal having a different instantaneous amplitude, a different instantaneous phase, etc. The modification can occur in a WFS prior to a DAC, as well as prior to a sin ROM component and/or a cos ROM component. Further, the notch can be dithered to enable formation of a deep notch. The notch can also undergo signal transitioning to enable formation of a deep notch. The restricted frequencies can be stored in a LUT against which an instantaneous frequency can be compared.

  9. Psychophysical tuning curves for very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Moore, Brian C.J.; Pedersen, Christian Sejer

    2010-01-01

    low frequencies, psychophysical tuning curves (PTCs) were obtained for centre frequencies of 31.5, 40, and 50 Hz. An equal-loudness-level contour was also obtained using closely spaced frequencies. This was used as a rough estimate of the shape of the individual middle-ear transfer function...... in the frequency range below 100 Hz. Preliminary results on 1 subject are described. The PTCs showed distinct irregularities around the signal frequency, which may reflect the influence of beats. However, the overall shapes of the PTCs were broad, indicating that frequency selectivity at low frequencies...

  10. 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.

  11. 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.

  12. Capacitive Proximity Sensor Has Longer Range

    Science.gov (United States)

    Vranish, John M.

    1992-01-01

    Capacitive proximity sensor on robot arm detects nearby object via capacitive effect of object on frequency of oscillator. Sensing element part of oscillator circuit operating at about 20 kHz. Total capacitance between sensing element and ground constitutes tuning capacitance of oscillator. Sensor circuit includes shield driven by replica of alternating voltage applied to sensing element. Driven shield concentrates sensing electrostatic field in exterior region to enhance sensitivity to object. Sensitivity and dynamic range has corresponding 12-to-1 improvement.

  13. Compact ranges in antenna and RCS measurements

    Science.gov (United States)

    Audone, B.

    1989-09-01

    With the increased complexity and extended frequency range of operation model measurements and far field test ranges are no longer suitable to satisfy the demand of accurate testing. Moreover plane wave test conditions are required for Radar Cross Section (RCS) measurements which represent a key point in stealth technology. Compact ranges represent the best test facilities available presently since they allow for indoor measurements under far field conditions in real time without any calculation effort. Several types of compact ranges are described and compared discussing their relevant advantages with regard to RCS and antenna measurements. In parallel to measuring systems sophisticated computer models were developed with such a high level of accuracy that it is questionable whether experiments give better results than theory. Tests performed on simple structures show the correlation between experimental results and theoretical ones derived on the basis of GTD computer codes.

  14. Resonant Frequency Control For the PIP-II Injector Test RFQ: Control Framework and Initial Results

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, A. L. [Colorado State U.; Biedron, S. G.; Milton, S. V.; Bowring, D.; Chase, B. E.; Edelen, J. P.; Nicklaus, D.; Steimel, J.

    2016-12-16

    For the PIP-II Injector Test (PI-Test) at Fermilab, a four-vane radio frequency quadrupole (RFQ) is designed to accelerate a 30-keV, 1-mA to 10-mA, H- beam to 2.1 MeV under both pulsed and continuous wave (CW) RF operation. The available headroom of the RF amplifiers limits the maximum allowable detuning to 3 kHz, and the detuning is controlled entirely via thermal regulation. Fine control over the detuning, minimal manual intervention, and fast trip recovery is desired. In addition, having active control over both the walls and vanes provides a wider tuning range. For this, we intend to use model predictive control (MPC). To facilitate these objectives, we developed a dedicated control framework that handles higher-level system decisions as well as executes control calculations. It is written in Python in a modular fashion for easy adjustments, readability, and portability. Here we describe the framework and present the first control results for the PI-Test RFQ under pulsed and CW operation.

  15. A fuzzy Bayesian approach to flood frequency estimation with imprecise historical information

    Science.gov (United States)

    Salinas, José Luis; Kiss, Andrea; Viglione, Alberto; Viertl, Reinhard; Blöschl, Günter

    2016-09-01

    This paper presents a novel framework that links imprecision (through a fuzzy approach) and stochastic uncertainty (through a Bayesian approach) in estimating flood probabilities from historical flood information and systematic flood discharge data. The method exploits the linguistic characteristics of historical source material to construct membership functions, which may be wider or narrower, depending on the vagueness of the statements. The membership functions are either included in the prior distribution or the likelihood function to obtain a fuzzy version of the flood frequency curve. The viability of the approach is demonstrated by three case studies that differ in terms of their hydromorphological conditions (from an Alpine river with bedrock profile to a flat lowland river with extensive flood plains) and historical source material (including narratives, town and county meeting protocols, flood marks and damage accounts). The case studies are presented in order of increasing fuzziness (the Rhine at Basel, Switzerland; the Werra at Meiningen, Germany; and the Tisza at Szeged, Hungary). Incorporating imprecise historical information is found to reduce the range between the 5% and 95% Bayesian credibility bounds of the 100 year floods by 45% and 61% for the Rhine and Werra case studies, respectively. The strengths and limitations of the framework are discussed relative to alternative (non-fuzzy) methods. The fuzzy Bayesian inference framework provides a flexible methodology that fits the imprecise nature of linguistic information on historical floods as available in historical written documentation.

  16. A fuzzy Bayesian approach to flood frequency estimation with imprecise historical information

    Science.gov (United States)

    Kiss, Andrea; Viglione, Alberto; Viertl, Reinhard; Blöschl, Günter

    2016-01-01

    Abstract This paper presents a novel framework that links imprecision (through a fuzzy approach) and stochastic uncertainty (through a Bayesian approach) in estimating flood probabilities from historical flood information and systematic flood discharge data. The method exploits the linguistic characteristics of historical source material to construct membership functions, which may be wider or narrower, depending on the vagueness of the statements. The membership functions are either included in the prior distribution or the likelihood function to obtain a fuzzy version of the flood frequency curve. The viability of the approach is demonstrated by three case studies that differ in terms of their hydromorphological conditions (from an Alpine river with bedrock profile to a flat lowland river with extensive flood plains) and historical source material (including narratives, town and county meeting protocols, flood marks and damage accounts). The case studies are presented in order of increasing fuzziness (the Rhine at Basel, Switzerland; the Werra at Meiningen, Germany; and the Tisza at Szeged, Hungary). Incorporating imprecise historical information is found to reduce the range between the 5% and 95% Bayesian credibility bounds of the 100 year floods by 45% and 61% for the Rhine and Werra case studies, respectively. The strengths and limitations of the framework are discussed relative to alternative (non‐fuzzy) methods. The fuzzy Bayesian inference framework provides a flexible methodology that fits the imprecise nature of linguistic information on historical floods as available in historical written documentation. PMID:27840456

  17. A fuzzy Bayesian approach to flood frequency estimation with imprecise historical information.

    Science.gov (United States)

    Salinas, José Luis; Kiss, Andrea; Viglione, Alberto; Viertl, Reinhard; Blöschl, Günter

    2016-09-01

    This paper presents a novel framework that links imprecision (through a fuzzy approach) and stochastic uncertainty (through a Bayesian approach) in estimating flood probabilities from historical flood information and systematic flood discharge data. The method exploits the linguistic characteristics of historical source material to construct membership functions, which may be wider or narrower, depending on the vagueness of the statements. The membership functions are either included in the prior distribution or the likelihood function to obtain a fuzzy version of the flood frequency curve. The viability of the approach is demonstrated by three case studies that differ in terms of their hydromorphological conditions (from an Alpine river with bedrock profile to a flat lowland river with extensive flood plains) and historical source material (including narratives, town and county meeting protocols, flood marks and damage accounts). The case studies are presented in order of increasing fuzziness (the Rhine at Basel, Switzerland; the Werra at Meiningen, Germany; and the Tisza at Szeged, Hungary). Incorporating imprecise historical information is found to reduce the range between the 5% and 95% Bayesian credibility bounds of the 100 year floods by 45% and 61% for the Rhine and Werra case studies, respectively. The strengths and limitations of the framework are discussed relative to alternative (non-fuzzy) methods. The fuzzy Bayesian inference framework provides a flexible methodology that fits the imprecise nature of linguistic information on historical floods as available in historical written documentation.

  18. A range-rate extraction unit for determining Doppler effect

    Science.gov (United States)

    1970-01-01

    Active ranging technique devised for VHF or S-band radar systems divides target Doppler frequency by counter-generated number that is proportional to transmitting frequency, thus producing target velocity data in terms of speed and distance relative to target transponder.

  19. 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

  20. 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...

  1. Magnetostatic wave oscillator frequencies

    Science.gov (United States)

    Sethares, J. C.; Stiglitz, M. R.; Weinberg, I. J.

    1981-03-01

    The frequencies of magnetostatic wave (MSW) oscillators employing three principal modes of propagation, surface (MSSW), forward (MSFVW), and backward (MSBVW) volume waves, have been investigated. Previous (MSW) oscillator papers dealt with MSSW. Oscillators were fabricated using LPE-YIG MSW delay lines in a feedback loop of a 2-4 GHz amplifier. Wide and narrow band transducers were employed. Oscillator frequency as a function of biasing field is in agreement with a theoretical analysis. The analysis predicts frequency in terms of material parameters, biasing field, and transducer geometry. With wide band transducers a comb of frequencies is generated. Narrow band transducers for MSSW and MSFVW select a single mode; and MSBVW selects two modes. Spurious modes, attributed to instrumentation, are more than 20 dB below the main response, and bandwidths are less than 0.005 percent. No other spurious modes are observed. MSW oscillators produce clean electronically tunable signals and appear attractive in frequency agile systems.

  2. Microfabricated ion frequency standard

    Science.gov (United States)

    Schwindt, Peter; Biedermann, Grant; Blain, Matthew G.; Stick, Daniel L.; Serkland, Darwin K.; Olsson, III, Roy H.

    2010-12-28

    A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

  3. Digital repetitive control under varying frequency conditions

    CERN Document Server

    Ramos, Germán A; Olm, Josep M

    2013-01-01

    The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area. Repetitive Control has proven to be an efficient way to face this topic. However, in some applications the frequency of the reference/disturbance signal is time-varying or uncertain. This causes an important performance degradation in the standard Repetitive Control scheme. This book presents some solutions to apply Repetitive Control in varying frequency conditions without loosing steady-state performance. It also includes a complete theoretical development and experimental results in two representative systems. The presented solutions are organized in two complementary branches: varying sampling period Repetitive Control and High Order Repetitive Control. The first approach allows dealing with large range frequency variations while the second allows dealing with small range frequency variations. The book also presents applications of the described techniques to a Roto-magnet plant and...

  4. 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

  5. Methods, computer readable media, and graphical user interfaces for analysis of frequency selective surfaces

    Science.gov (United States)

    Kotter, Dale K [Shelley, ID; Rohrbaugh, David T [Idaho Falls, ID

    2010-09-07

    A frequency selective surface (FSS) and associated methods for modeling, analyzing and designing the FSS are disclosed. The FSS includes a pattern of conductive material formed on a substrate to form an array of resonance elements. At least one aspect of the frequency selective surface is determined by defining a frequency range including multiple frequency values, determining a frequency dependent permittivity across the frequency range for the substrate, determining a frequency dependent conductivity across the frequency range for the conductive material, and analyzing the frequency selective surface using a method of moments analysis at each of the multiple frequency values for an incident electromagnetic energy impinging on the frequency selective surface. The frequency dependent permittivity and the frequency dependent conductivity are included in the method of moments analysis.

  6. Asymptotic Waveform Evaluation (AWE) Technique for Frequency Domain Electromagnetic Analysis

    Science.gov (United States)

    Cockrell, C. R.; Beck, F. B.

    1996-01-01

    The Asymptotic Waveform Evaluation (AWE) technique is applied to a generalized frequency domain electromagnetic problem. Most of the frequency domain techniques in computational electromagnetics result in a matrix equation, which is solved at a single frequency. In the AWE technique, the Taylor series expansion around that frequency is applied to the matrix equation. The coefficients of the Taylor's series are obtained in terms of the frequency derivatives of the matrices evaluated at the expansion frequency. The coefficients hence obtained will be used to predict the frequency response of the system over a frequency range. The detailed derivation of the coefficients (called 'moments') is given along with an illustration for electric field integral equation (or Method of Moments) technique. The radar cross section (RCS) frequency response of a square plate is presented using the AWE technique and is compared with the exact solution at various frequencies.

  7. Novel high-frequency air transducers

    Science.gov (United States)

    Schiller, S.; Hsieh, C.-K.; Chou, C.-H.; Khuri-Yakub, B. T.

    The properties of ligneous materials have been evaluated in order to improve the insertion loss and bandwidth of air-based ultrasonic transducers. It is found that cork and balsa wood have the appropriate impedance to match with air, though their attenuation coefficients are prohibitive for high-frequency operation. For multiple matching layer devices, ligneous materials could be made useful in the 1-10 MHz frequency range.

  8. Frequency Estimation Techniques For High Dynamic Trajectories

    Science.gov (United States)

    Vilnrotter, V. A.; Hinedi, S. M.; Kumar, R.

    1989-01-01

    Report presents comparative study of four techniques for estimating frequency of sinusoidal signal received in presence of noise when transmitter and/or receiver experiencing very high dynamics. Four techniques involve approximate-maximum-likelihood estimator, extended Kalman filter, cross-product automatic frequency control loop, and digital phase locked loop, respectively. In numerical simulations, each technique applied to signal from transmitter maneuvering along common trajectory; performance of each examined to determine its useful operating range, and performances compared.

  9. The History of the Naval Torpedo Tracking Ranges at Keyport

    Science.gov (United States)

    1998-08-01

    1961, negotiations were begun with Canada for the installation and joint operation of an acoustic range near Ballenas Island, in the Strait of Georgia...After several exploratory trips were made to Ballenas and Winchelsea Islands, construction of the range, based on the low frequency 75 kHz tracking...The array cables were temporarily terminated at a trailer on South Ballenas Island that contained the range tracking computer and served as a range

  10. Magnetoplasmonic RF mixing and nonlinear frequency generation

    Energy Technology Data Exchange (ETDEWEB)

    Firby, C. J., E-mail: firby@ualberta.ca; Elezzabi, A. Y. [Ultrafast Optics and Nanophotonics Laboratory, Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada)

    2016-07-04

    We present the design of a magnetoplasmonic Mach-Zehnder interferometer (MZI) modulator facilitating radio-frequency (RF) mixing and nonlinear frequency generation. This is achieved by forming the MZI arms from long-range dielectric-loaded plasmonic waveguides containing bismuth-substituted yttrium iron garnet (Bi:YIG). The magnetization of the Bi:YIG can be driven in the nonlinear regime by RF magnetic fields produced around adjacent transmission lines. Correspondingly, the nonlinear temporal dynamics of the transverse magnetization component are mapped onto the nonreciprocal phase shift in the MZI arms, and onto the output optical intensity signal. We show that this tunable mechanism can generate harmonics, frequency splitting, and frequency down-conversion with a single RF excitation, as well as RF mixing when driven by two RF signals. This magnetoplasmonic component can reduce the number of electrical sources required to generate distinct optical modulation frequencies and is anticipated to satisfy important applications in integrated optics.

  11. Effect of efferent activation on binaural frequency selectivity.

    Science.gov (United States)

    Verhey, Jesko L; Kordus, Monika; Drga, Vit; Yasin, Ifat

    2017-07-01

    Binaural notched-noise experiments indicate a reduced frequency selectivity of the binaural system compared to monaural processing. The present study investigates how auditory efferent activation (via the medial olivocochlear system) affects binaural frequency selectivity in normal-hearing listeners. Thresholds were measured for a 1-kHz signal embedded in a diotic notched-noise masker for various notch widths. The signal was either presented in phase (diotic) or in antiphase (dichotic), gated with the noise. Stimulus duration was 25 ms, in order to avoid efferent activation due to the masker or the signal. A bandpass-filtered noise precursor was presented prior to the masker and signal stimuli to activate the efferent system. The silent interval between the precursor and the masker-signal complex was 50 ms. For comparison, thresholds for detectability of the masked signal were also measured in a baseline condition without the precursor and, in addition, without the masker. On average, the results of the baseline condition indicate an effectively wider binaural filter, as expected. For both signal phases, the addition of the precursor results in effectively wider filters, which is in agreement with the hypothesis that cochlear gain is reduced due to the presence of the precursor. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Primary, secondary and tertiary frequency control in dynamic security analyses of electric power interconnections

    Directory of Open Access Journals (Sweden)

    Ivanović Milan

    2012-01-01

    Full Text Available This paper presents the incorporation of primary, secondary and tertiary frequency control in the dynamic security analyses of electric power interconnections. This was done in accordance with the wider environment of the existing state of the Serbian power system. The improved software for dynamic security analysis has been tested on the regional transmission network, which includes power systems of Serbia, Montenegro, Bosnia and Herzegovina, Croatia, Hungary, Macedonia, Romania, Bulgaria, Greece and Albania.

  13. Digital Radio Frequency Memories

    Science.gov (United States)

    Hey-Shipton, Gregory L.

    The Digital RF Memory (DRFM) is gradually replacing the recirculating Frequency Memory Loop (FML). The shortcomings of the FML in the area of limited storage time, single signal processing, and limited ECM capabilities are overcome by the use of the DRFM. There are several architectures for the DRFM but all of them accomplish the same basic function: to convert an incoming RF signal to a low enough frequency to allow storage in a digital memory and subsequent upconversion to the original signal frequency. Multiple signal handling capabilities on a pulse by pulse basis and software controlled ECM generation make the DRFM a powerful addition to any ECM suite.

  14. Applications of Graphene at Microwave Frequencies

    Directory of Open Access Journals (Sweden)

    M. Bozzi

    2015-09-01

    Full Text Available In view to the epochal scenarios that nanotechnology discloses, nano-electronics has the potential to introduce a paradigm shift in electronic systems design similar to that of the transition from vacuum tubes to semiconductor devices. Since low dimensional (1D and 2D nano-structured materials exhibit unprecedented electro-mechanical properties in a wide frequency range, including radio-frequencies (RF, microwave nano-electronics provides an enormous and yet widely undiscovered opportunity for the engineering community. Carbon nano-electronics is one of the main research routes of RF/microwave nano-electronics. In particular, graphene has shown proven results as an emblematic protagonist, and a real solution for a wide variety of microwave electronic devices and circuits. This paper introduces graphene properties in the microwave range, and presents a paradigm of novel graphene-based devices and applications in the microwave/RF frequency range.

  15. Improved Semiconductor Lattice Parameters and Band Gaps from a Middle-Range Screened Hybrid Functional

    OpenAIRE

    Lucero, Melissa J.; Henderson, Thomas M.; Scuseria, Gustavo E.

    2011-01-01

    We show that the middle-range exchange-correlation hybrid of Henderson, Izmaylov, Scuseria and Savin (HISS) performs extremely well for elemental and binary semiconductors with narrow or visible spectrum band gaps, as well as some wider gap or more ionic systems used commercially. The lattice parameters are superior to those predicted by the screened hybrid functional of Heyd, Scuseria and Ernzerhof (HSE), and provide a significant improvement over geometries predicted by semilocal functional...

  16. Collective Thomson scattering measurements with high frequency resolution at TEXTOR

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Korsholm, Søren Bang

    2010-01-01

    We discuss the development and first results of a receiver system for the collective Thomson scattering (CTS) diagnostic at TEXTOR with frequency resolution in the megahertz range or better. The improved frequency resolution expands the diagnostic range and utility of CTS measurements in general...

  17. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  18. Lunch frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Krølner, Rikke

    2016-01-01

    frequency was most common among students who were boys, 13- and 15-year-olds, from medium and low family social class, descendants of immigrants, living in a single-parent family and in a reconstructed family. School-level analyses suggested that having access to a canteen at school was associated with low......OBJECTIVE: To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch...... frequency and school characteristics vary by gender and age groups. DESIGN: Cross-sectional study in which students and school headmasters completed self-administered questionnaires. Associations were estimated by multilevel multivariate logistic regression. SETTING: The Danish arm of the Health Behaviour...

  19. Fast, precise, and widely tunable frequency control of an optical parametric oscillator referenced to a frequency comb

    Science.gov (United States)

    Prehn, Alexander; Glöckner, Rosa; Rempe, Gerhard; Zeppenfeld, Martin

    2017-03-01

    Optical frequency combs (OFCs) provide a convenient reference for the frequency stabilization of continuous-wave lasers. We demonstrate a frequency control method relying on tracking over a wide range and stabilizing the beat note between the laser and the OFC. The approach combines fast frequency ramps on a millisecond timescale in the entire mode-hop free tuning range of the laser and precise stabilization to single frequencies. We apply it to a commercially available optical parametric oscillator (OPO) and demonstrate tuning over more than 60 GHz with a ramping speed up to 3 GHz/ms. Frequency ramps spanning 15 GHz are performed in less than 10 ms, with the OPO instantly relocked to the OFC after the ramp at any desired frequency. The developed control hardware and software are able to stabilize the OPO to sub-MHz precision and to perform sequences of fast frequency ramps automatically.

  20. Amplified, frequency swept lasers for frequency domain reflectometry and OCT imaging: design and scaling principles.

    Science.gov (United States)

    Huber, R; Wojtkowski, M; Taira, K; Fujimoto, J; Hsu, K

    2005-05-02

    We demonstrate a high-speed, frequency swept, 1300 nm laser source for frequency domain reflectometry and OCT with Fourier domain/swept-source detection. The laser uses a fiber coupled, semiconductor amplifier and a tunable fiber Fabry-Perot filter. We present scaling principles which predict the maximum frequency sweep speed and trade offs in output power, noise and instantaneous linewidth performance. The use of an amplification stage for increasing output power and for spectral shaping is discussed in detail. The laser generates ~45 mW instantaneous peak power at 20 kHz sweep rates with a tuning range of ~120 nm full width. In frequency domain reflectometry and OCT applications the frequency swept laser achieves 108 dB sensitivity and ~10 mum axial resolution in tissue. We also present a fast algorithm for real time calibration of the fringe signal to equally spaced sampling in frequency for high speed OCT image preview.