WorldWideScience

Sample records for maximum fundamental frequency

  1. Joint fundamental frequency and order estimation using optimal filtering

    Directory of Open Access Journals (Sweden)

    Jakobsson Andreas

    2011-01-01

    Full Text Available Abstract In this paper, the problem of jointly estimating the number of harmonics and the fundamental frequency of periodic signals is considered. We show how this problem can be solved using a number of methods that either are or can be interpreted as filtering methods in combination with a statistical model selection criterion. The methods in question are the classical comb filtering method, a maximum likelihood method, and some filtering methods based on optimal filtering that have recently been proposed, while the model selection criterion is derived herein from the maximum a posteriori principle. The asymptotic properties of the optimal filtering methods are analyzed and an order-recursive efficient implementation is derived. Finally, the estimators have been compared in computer simulations that show that the optimal filtering methods perform well under various conditions. It has previously been demonstrated that the optimal filtering methods perform extremely well with respect to fundamental frequency estimation under adverse conditions, and this fact, combined with the new results on model order estimation and efficient implementation, suggests that these methods form an appealing alternative to classical methods for analyzing multi-pitch signals.

  2. Fast fundamental frequency estimation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

    2017-01-01

    Modelling signals as being periodic is common in many applications. Such periodic signals can be represented by a weighted sum of sinusoids with frequencies being an integer multiple of the fundamental frequency. Due to its widespread use, numerous methods have been proposed to estimate the funda...

  3. [Fundamental frequency analysis - a contribution to the objective examination of the speaking and singing voice (author's transl)].

    Science.gov (United States)

    Schultz-Coulon, H J

    1975-07-01

    The applicability of a newly developed fundamental frequency analyzer to diagnosis in phoniatrics is reviewed. During routine voice examination, the analyzer allows a quick and accurate measurement of fundamental frequency and sound level of the speaking voice, and of vocal range and maximum phonation time. By computing fundamental frequency histograms, the median fundamental frequency and the total pitch range can be better determined and compared. Objective studies of certain technical faculties of the singing voice, which usually are estimated subjectively by the speech therapist, may now be done by means of this analyzer. Several examples demonstrate the differences between correct and incorrect phonation. These studies compare the pitch perturbations during the crescendo and decrescendo of a swell-tone, and show typical traces of staccato, thrill and yodel. Conclusions of the study indicate that fundamental frequency analysis is a valuable supplemental method for objective voice examination.

  4. Default Bayesian Estimation of the Fundamental Frequency

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2013-01-01

    Joint fundamental frequency and model order esti- mation is an important problem in several applications. In this paper, a default estimation algorithm based on a minimum of prior information is presented. The algorithm is developed in a Bayesian framework, and it can be applied to both real....... Moreover, several approximations of the posterior distributions on the fundamental frequency and the model order are derived, and one of the state-of-the-art joint fundamental frequency and model order estimators is demonstrated to be a special case of one of these approximations. The performance...

  5. A Kalman-based Fundamental Frequency Estimation Algorithm

    DEFF Research Database (Denmark)

    Shi, Liming; Nielsen, Jesper Kjær; Jensen, Jesper Rindom

    2017-01-01

    Fundamental frequency estimation is an important task in speech and audio analysis. Harmonic model-based methods typically have superior estimation accuracy. However, such methods usually as- sume that the fundamental frequency and amplitudes are station- ary over a short time frame. In this pape...

  6. 33 CFR 86.03 - Limits of fundamental frequencies.

    Science.gov (United States)

    2010-07-01

    ... of fundamental frequencies. To ensure a wide variety of whistle characteristics, the fundamental... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Limits of fundamental frequencies. 86.03 Section 86.03 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...

  7. Maximum Entropy Fundamentals

    Directory of Open Access Journals (Sweden)

    F. Topsøe

    2001-09-01

    Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over

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

    Directory of Open Access Journals (Sweden)

    Ingo Titze

    2016-06-01

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

  9. Accurate Estimation of Low Fundamental Frequencies from Real-Valued Measurements

    DEFF Research Database (Denmark)

    Christensen, Mads Græsbøll

    2013-01-01

    In this paper, the difficult problem of estimating low fundamental frequencies from real-valued measurements is addressed. The methods commonly employed do not take the phenomena encountered in this scenario into account and thus fail to deliver accurate estimates. The reason for this is that the......In this paper, the difficult problem of estimating low fundamental frequencies from real-valued measurements is addressed. The methods commonly employed do not take the phenomena encountered in this scenario into account and thus fail to deliver accurate estimates. The reason...... for this is that they employ asymptotic approximations that are violated when the harmonics are not well-separated in frequency, something that happens when the observed signal is real-valued and the fundamental frequency is low. To mitigate this, we analyze the problem and present some exact fundamental frequency estimators...

  10. Instantaneous Fundamental Frequency Estimation with Optimal Segmentation for Nonstationary Voiced Speech

    DEFF Research Database (Denmark)

    Nørholm, Sidsel Marie; Jensen, Jesper Rindom; Christensen, Mads Græsbøll

    2016-01-01

    In speech processing, the speech is often considered stationary within segments of 20–30 ms even though it is well known not to be true. In this paper, we take the non-stationarity of voiced speech into account by using a linear chirp model to describe the speech signal. We propose a maximum...... likelihood estimator of the fundamental frequency and chirp rate of this model, and show that it reaches the Cramer-Rao bound. Since the speech varies over time, a fixed segment length is not optimal, and we propose to make a segmentation of the signal based on the maximum a posteriori (MAP) criterion. Using...... of the chirp model than the harmonic model to the speech signal. The methods are based on an assumption of white Gaussian noise, and, therefore, two prewhitening filters are also proposed....

  11. Fundamental Frequency and Model Order Estimation Using Spatial Filtering

    DEFF Research Database (Denmark)

    Karimian-Azari, Sam; Jensen, Jesper Rindom; Christensen, Mads Græsbøll

    2014-01-01

    extend this procedure to account for inharmonicity using unconstrained model order estimation. The simulations show that beamforming improves the performance of the joint estimates of fundamental frequency and the number of harmonics in low signal to interference (SIR) levels, and an experiment......In signal processing applications of harmonic-structured signals, estimates of the fundamental frequency and number of harmonics are often necessary. In real scenarios, a desired signal is contaminated by different levels of noise and interferers, which complicate the estimation of the signal...... parameters. In this paper, we present an estimation procedure for harmonic-structured signals in situations with strong interference using spatial filtering, or beamforming. We jointly estimate the fundamental frequency and the constrained model order through the output of the beamformers. Besides that, we...

  12. Orthogonal frequency division multiple access fundamentals and applications

    CERN Document Server

    Jiang, Tao; Zhang, Yan

    2010-01-01

    Supported by the expert-level advice of pioneering researchers, Orthogonal Frequency Division Multiple Access Fundamentals and Applications provides a comprehensive and accessible introduction to the foundations and applications of one of the most promising access technologies for current and future wireless networks. It includes authoritative coverage of the history, fundamental principles, key techniques, and critical design issues of OFDM systems. Covering various techniques of effective resource management for OFDM/OFDMA-based wireless communication systems, this cutting-edge reference:Add

  13. Effect of Training Frequency on Maximum Expiratory Pressure

    Science.gov (United States)

    Anand, Supraja; El-Bashiti, Nour; Sapienza, Christine

    2012-01-01

    Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary…

  14. Fundamental Frequency Tuning and Its Influence on LHC 200MHz ACN Cavity

    CERN Document Server

    Linnecar, Trevor Paul R; Tückmantel, Joachim; CERN. Geneva. SPS and LHC Division

    2001-01-01

    To study the influence of the tuner on the fundamental mode frequency, the Q factor as well as the shunt impedance of the LHC 200MHz ACN cavities, 3D simulations have been done in the frequency domain using MAFIA. Curves giving the variation of RF frequency and other RF parameters with tuner position relative to the inner surface of the cavity have been obtained for the fundamental mode. This paper details the simulation results.

  15. Fast and Statistically Efficient Fundamental Frequency Estimation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

    2016-01-01

    Fundamental frequency estimation is a very important task in many applications involving periodic signals. For computational reasons, fast autocorrelation-based estimation methods are often used despite parametric estimation methods having superior estimation accuracy. However, these parametric...... a recursive solver. Via benchmarks, we demonstrate that the computation time is reduced by approximately two orders of magnitude. The proposed fast algorithm is available for download online....

  16. The Siren song of vocal fundamental frequency for romantic relationships

    Directory of Open Access Journals (Sweden)

    Sarah eWeusthoff

    2013-07-01

    Full Text Available A multitude of factors contribute to why and how romantic relationships are formed as well as whether they ultimately succeed or fail. Drawing on evolutionary models of attraction and speech production as well as integrative models of relationship functioning, this review argues that paralinguistic cues (more specifically the fundamental frequency of the voice that are initially a strong source of attraction also increase couples’ risk for relationship failure. Conceptual similarities and differences between the multiple operationalizations and interpretations of vocal fundamental frequency are discussed and guidelines are presented for understanding both convergent and non-convergent findings. Implications for clinical practice and future research are discussed.

  17. The siren song of vocal fundamental frequency for romantic relationships.

    Science.gov (United States)

    Weusthoff, Sarah; Baucom, Brian R; Hahlweg, Kurt

    2013-01-01

    A multitude of factors contribute to why and how romantic relationships are formed as well as whether they ultimately succeed or fail. Drawing on evolutionary models of attraction and speech production as well as integrative models of relationship functioning, this review argues that paralinguistic cues (more specifically the fundamental frequency of the voice) that are initially a strong source of attraction also increase couples' risk for relationship failure. Conceptual similarities and differences between the multiple operationalizations and interpretations of vocal fundamental frequency are discussed and guidelines are presented for understanding both convergent and non-convergent findings. Implications for clinical practice and future research are discussed.

  18. Fundamental Frequency Estimation using Polynomial Rooting of a Subspace-Based Method

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2010-01-01

    improvements compared to HMUSIC. First, by using the proposed method we can obtain an estimate of the fundamental frequency without doing a grid search like in HMUSIC. This is due to that the fundamental frequency is estimated as the argument of the root lying closest to the unit circle. Second, we obtain...... a higher spectral resolution compared to HMUSIC which is a property of polynomial rooting methods. Our simulation results show that the proposed method is applicable to real-life signals, and that we in most cases obtain a higher spectral resolution than HMUSIC....

  19. Influences of Fundamental Frequency, Formant Frequencies, Aperiodicity, and Spectrum Level on the Perception of Voice Gender

    Science.gov (United States)

    Skuk, Verena G.; Schweinberger, Stefan R.

    2014-01-01

    Purpose: To determine the relative importance of acoustic parameters (fundamental frequency [F0], formant frequencies [FFs], aperiodicity, and spectrum level [SL]) on voice gender perception, the authors used a novel parameter-morphing approach that, unlike spectral envelope shifting, allows the application of nonuniform scale factors to transform…

  20. Improvement of Microtremor Data Filtering and Processing Methods Used in Determining the Fundamental Frequency of Urban Areas

    Science.gov (United States)

    Mousavi Anzehaee, Mohammad; Adib, Ahmad; Heydarzadeh, Kobra

    2015-10-01

    The manner of microtremor data collection and filtering operation and also the method used for processing have a considerable effect on the accuracy of estimation of dynamic soil parameters. In this paper, running variance method was used to improve the automatic detection of data sections infected by local perturbations. In this method, the microtremor data running variance is computed using a sliding window. Then the obtained signal is used to remove the ranges of data affected by perturbations from the original data. Additionally, to determinate the fundamental frequency of a site, this study has proposed a statistical characteristics-based method. Actually, statistical characteristics, such as the probability density graph and the average and the standard deviation of all the frequencies corresponding to the maximum peaks in the H/ V spectra of all data windows, are used to differentiate the real peaks from the false peaks resulting from perturbations. The methods have been applied to the data recorded for the City of Meybod in central Iran. Experimental results show that the applied methods are able to successfully reduce the effects of extensive local perturbations on microtremor data and eventually to estimate the fundamental frequency more accurately compared to other common methods.

  1. Maximum-likelihood methods for array processing based on time-frequency distributions

    Science.gov (United States)

    Zhang, Yimin; Mu, Weifeng; Amin, Moeness G.

    1999-11-01

    This paper proposes a novel time-frequency maximum likelihood (t-f ML) method for direction-of-arrival (DOA) estimation for non- stationary signals, and compares this method with conventional maximum likelihood DOA estimation techniques. Time-frequency distributions localize the signal power in the time-frequency domain, and as such enhance the effective SNR, leading to improved DOA estimation. The localization of signals with different t-f signatures permits the division of the time-frequency domain into smaller regions, each contains fewer signals than those incident on the array. The reduction of the number of signals within different time-frequency regions not only reduces the required number of sensors, but also decreases the computational load in multi- dimensional optimizations. Compared to the recently proposed time- frequency MUSIC (t-f MUSIC), the proposed t-f ML method can be applied in coherent environments, without the need to perform any type of preprocessing that is subject to both array geometry and array aperture.

  2. Fundamental frequency and voice perturbation measures in smokers and non-smokers: An acoustic and perceptual study

    Science.gov (United States)

    Freeman, Allison

    This research examined the fundamental frequency and perturbation (jitter % and shimmer %) measures in young adult (20-30 year-old) and middle-aged adult (40-55 year-old) smokers and non-smokers; there were 36 smokers and 36 non-smokers. Acoustic analysis was carried out utilizing one task: production of sustained /a/. These voice samples were analyzed utilizing Multi-Dimensional Voice Program (MDVP) software, which provided values for fundamental frequency, jitter %, and shimmer %.These values were analyzed for trends regarding smoking status, age, and gender. Statistical significance was found regarding the fundamental frequency, jitter %, and shimmer % for smokers as compared to non-smokers; smokers were found to have significantly lower fundamental frequency values, and significantly higher jitter % and shimmer % values. Statistical significance was not found regarding fundamental frequency, jitter %, and shimmer % for age group comparisons. With regard to gender, statistical significance was found regarding fundamental frequency; females were found to have statistically higher fundamental frequencies as compared to males. However, the relationships between gender and jitter % and shimmer % lacked statistical significance. These results indicate that smoking negatively affects voice quality. This study also examined the ability of untrained listeners to identify smokers and non-smokers based on their voices. Results of this voice perception task suggest that listeners are not accurately able to identify smokers and non-smokers, as statistical significance was not reached. However, despite a lack of significance, trends in data suggest that listeners are able to utilize voice quality to identify smokers and non-smokers.

  3. A wearable multichannel tactile display of voice fundamental frequency.

    Science.gov (United States)

    Yeung, E; Boothroyd, A; Redmond, C

    1988-12-01

    This paper describes a wearable sensory aid that provides the deaf with tactually encoded information about intonation. Fundamental frequency is represented as both place and rate of vibration in a linear array of solenoids. Pitch extraction is accomplished through low-pass filtering and peak detection. A microcomputer is used to measure pitch period, which in turn determines which of the solenoids is actuated. By comparing consecutive periods, the system discriminates against random, noise-related inputs. The device is switchable between 1-, 8-, and 16-channel operation. The electronics package is contained in a case that may be worn on a belt. The solenoid array is worn on the forearm. The system is powered by five, rechargeable lithium cells and runs for at least 6 hours between charges. Proposed developments include the incorporation of digital pitch extraction methods and the option to use the spatial output dimension to encode speech parameters other than fundamental frequency.

  4. Rotational structure of the five lowest frequency fundamental vibrational states of dimethylsulfoxide

    Science.gov (United States)

    Cuisset, Arnaud; Drumel, Marie-Aline Martin; Hindle, Francis; Mouret, Gaël; Sadovskií, Dmitrií A.

    2013-10-01

    We report on the successful extended analysis of the high-frequency (200-700 GHz) part of the gas phase (sub)mm-wave spectra of dimethylsulfoxide (DMSO). The spectrum was recorded at 100 kHz resolution using a solid state subTHz spectrometer. The five lowest energy fundamental vibrational states of DMSO with frequencies below 400 cm-1 were observed as sidebands along with the main 0←0 band. Neglecting the internal rotation of methyls, our rotational Hamiltonian reproduced the spectrum to the subMHz accuracy. We have found that the asymmetric bending state ν23 is the only low frequency fundamental vibrational state with the "anomalous" rotational structure uncovered in Cuisset et al. [1]. dmsomw 2013-09-04 15:03

  5. Bayesian analysis of rotating machines - A statistical approach to estimate and track the fundamental frequency

    DEFF Research Database (Denmark)

    Pedersen, Thorkild Find

    2003-01-01

    frequency and the related frequencies as orders of the fundamental frequency. When analyzing rotating or reciprocating machines it is important to know the running speed. Usually this requires direct access to the rotating parts in order to mount a dedicated tachometer probe. In this thesis different......Rotating and reciprocating mechanical machines emit acoustic noise and vibrations when they operate. Typically, the noise and vibrations are concentrated in narrow frequency bands related to the running speed of the machine. The frequency of the running speed is referred to as the fundamental...

  6. Spatial stability of jets - the nonaxisymmetric fundamental and reflection modes

    International Nuclear Information System (INIS)

    Hardee, P.E.

    1987-01-01

    A spatial stability analysis of the relativistic dispersion relation governing the growth and propagation of harmonic components comprising a perturbation to the surface of a cylindrical jet is performed. The spatial growth of harmonic components associated with the nonaxisymmetric fundamental solution and reflection solutions of several Fourier modes are analyzed. Approximate analytical expressions describing resonant frequencies and wavelengths, and maximum growth rates at resonance applicable to relativistic jets are found from the dispersion relation, and the nature of the resonances is explored. On transonic jets there is only a fundamental solution for each Fourier mode with no resonance or maximum growth rate. On supersonic jets there is a fundamental solution and reflection solutions for each Fourier mode, and each solution contains a resonance at which the growth rate is a maximum. A numerical analysis of the fundamental and first three reflection solutions of the axisymmetric and first three nonaxisymmetric Fourier modes is performed. The numerical analysis is restricted to nonrelativistic flows but otherwise covers a broad range of Mach numbers and jet densities. The numerical results are used along with the analytical results to obtain accurate expressions for resonant frequencies, wavelengths, and growth rates as a function of Mach numnber and jet density. In all cases the fastest spatial growth rate at a given frequency is of harmonic components associated with the fundamental solution of one of the nonaxisymmetric Fourier modes. The application of these results to jet structure and implication of these results for jet structure in extragalactic radio sources are considered. 23 references

  7. Fundamental Frequency Extraction Method using Central Clipping and its Importance for the Classification of Emotional State

    Directory of Open Access Journals (Sweden)

    Pavol Partila

    2012-01-01

    Full Text Available The paper deals with a classification of emotional state. We implemented a method for extracting the fundamental speech signal frequency by means of a central clipping and examined a correlation between emotional state and fundamental speech frequency. For this purpose, we applied an approach of exploratory data analysis. The ANOVA (Analysis of variance test confirmed that a modification in the speaker's emotional state changes the fundamental frequency of human vocal tract. The main contribution of the paper lies in investigation, of central clipping method by the ANOVA.

  8. The Effect of Communications Medium on the Fundamental Frequency of Speech.

    Science.gov (United States)

    Noll, A. Michael

    1978-01-01

    Describes the results of preliminary experiments to investigate the effects of communications medium (face-to-face and two-way closed circuit television) on the fundamental frequency of speakers in a dyadic communications situation. (JMF)

  9. Fundamental Frequency Estimation of the Speech Signal Compressed by MP3 Algorithm Using PCC Interpolation

    Directory of Open Access Journals (Sweden)

    MILIVOJEVIC, Z. N.

    2010-02-01

    Full Text Available In this paper the fundamental frequency estimation results of the MP3 modeled speech signal are analyzed. The estimation of the fundamental frequency was performed by the Picking-Peaks algorithm with the implemented Parametric Cubic Convolution (PCC interpolation. The efficiency of PCC was tested for Catmull-Rom, Greville and Greville two-parametric kernel. Depending on MSE, a window that gives optimal results was chosen.

  10. Fundamental frequency characteristics of Jordanian Arabic speakers.

    Science.gov (United States)

    Natour, Yaser S; Wingate, Judith M

    2009-09-01

    This study is the first in a series of investigations designed to test the acoustic characteristics of the normal Arabic voice. The subjects were three hundred normal Jordanian Arabic speakers (100 adult males, 100 adult females, and 100 children). The subjects produced a sustained phonation of the vowel /a:/ and stated their complete names (i.e. first, second, third and surname) using a carrier phrase. The samples were analyzed using the Multi Dimensional Voice Program (MDVP). Fundamental frequency (F0) from the /a:/ and speaking fundamental frequency (SF0) from the sentence were analyzed. Results revealed a significant difference of both F0 and SF0 values among adult Jordanian Arabic-speaking males (F0=131.34Hz +/- 18.65, SF0=137.45 +/- 18.93), females (F0=231.13Hz +/- 20.86, SF0=230.84 +/- 16.50) and children (F0=270.93Hz +/- 20.01, SF0=278.04 +/- 32.07). Comparison with other ethnicities indicated that F0 values of adult Jordanian Arabic-speaking males and females are generally consistent with adult Caucasian and African-American values. However, for Jordanian Arabic-speaking children, a higher trend in F0 values was present than their Western counterparts. SF0 values for adult Jordanian Arabic-speaking males are generally consistent with the adult Caucasian male SF0 values. However, SF0 values of adult Jordanian-speaking females and children were relatively higher than the reported Western values. It is recommended that speech-language pathologists in Arabic-speaking countries, Jordan in specific, utilize the new data provided (F0 and SF0) when evaluating and/or treating Arabic-speaking patients. Due to its cross-linguistic variability, SF0 emerged as a preferred measurement when conducting cross-cultural comparisons of voice features.

  11. High-frequency maximum observable shaking map of Italy from fault sources

    KAUST Repository

    Zonno, Gaetano

    2012-03-17

    We present a strategy for obtaining fault-based maximum observable shaking (MOS) maps, which represent an innovative concept for assessing deterministic seismic ground motion at a regional scale. Our approach uses the fault sources supplied for Italy by the Database of Individual Seismogenic Sources, and particularly by its composite seismogenic sources (CSS), a spatially continuous simplified 3-D representation of a fault system. For each CSS, we consider the associated Typical Fault, i. e., the portion of the corresponding CSS that can generate the maximum credible earthquake. We then compute the high-frequency (1-50 Hz) ground shaking for a rupture model derived from its associated maximum credible earthquake. As the Typical Fault floats within its CSS to occupy all possible positions of the rupture, the high-frequency shaking is updated in the area surrounding the fault, and the maximum from that scenario is extracted and displayed on a map. The final high-frequency MOS map of Italy is then obtained by merging 8,859 individual scenario-simulations, from which the ground shaking parameters have been extracted. To explore the internal consistency of our calculations and validate the results of the procedure we compare our results (1) with predictions based on the Next Generation Attenuation ground-motion equations for an earthquake of M w 7.1, (2) with the predictions of the official Italian seismic hazard map, and (3) with macroseismic intensities included in the DBMI04 Italian database. We then examine the uncertainties and analyse the variability of ground motion for different fault geometries and slip distributions. © 2012 Springer Science+Business Media B.V.

  12. High-frequency maximum observable shaking map of Italy from fault sources

    KAUST Repository

    Zonno, Gaetano; Basili, Roberto; Meroni, Fabrizio; Musacchio, Gemma; Mai, Paul Martin; Valensise, Gianluca

    2012-01-01

    We present a strategy for obtaining fault-based maximum observable shaking (MOS) maps, which represent an innovative concept for assessing deterministic seismic ground motion at a regional scale. Our approach uses the fault sources supplied for Italy by the Database of Individual Seismogenic Sources, and particularly by its composite seismogenic sources (CSS), a spatially continuous simplified 3-D representation of a fault system. For each CSS, we consider the associated Typical Fault, i. e., the portion of the corresponding CSS that can generate the maximum credible earthquake. We then compute the high-frequency (1-50 Hz) ground shaking for a rupture model derived from its associated maximum credible earthquake. As the Typical Fault floats within its CSS to occupy all possible positions of the rupture, the high-frequency shaking is updated in the area surrounding the fault, and the maximum from that scenario is extracted and displayed on a map. The final high-frequency MOS map of Italy is then obtained by merging 8,859 individual scenario-simulations, from which the ground shaking parameters have been extracted. To explore the internal consistency of our calculations and validate the results of the procedure we compare our results (1) with predictions based on the Next Generation Attenuation ground-motion equations for an earthquake of M w 7.1, (2) with the predictions of the official Italian seismic hazard map, and (3) with macroseismic intensities included in the DBMI04 Italian database. We then examine the uncertainties and analyse the variability of ground motion for different fault geometries and slip distributions. © 2012 Springer Science+Business Media B.V.

  13. Gravitational Waves and the Maximum Spin Frequency of Neutron Stars

    NARCIS (Netherlands)

    Patruno, A.; Haskell, B.; D'Angelo, C.

    2012-01-01

    In this paper, we re-examine the idea that gravitational waves are required as a braking mechanism to explain the observed maximum spin frequency of neutron stars. We show that for millisecond X-ray pulsars, the existence of spin equilibrium as set by the disk/magnetosphere interaction is sufficient

  14. Welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems using fundamental- and higher-resonance frequencies.

    Science.gov (United States)

    Tsujino, Jiromaru; Hongoh, Misugi; Yoshikuni, Masafumi; Hashii, Hidekazu; Ueoka, Tetsugi

    2004-04-01

    The welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems that are driven at only the fundamental-resonance frequency vibration were compared, and also those of the welding systems that were driven at the fundamental and several higher resonance frequencies simultaneously were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. For welding of rather thin or small specimens, as the fundamental frequency of these welding systems is higher and the numbers of driven higher frequencies are driven simultaneously, larger welded area and weld strength were obtained.

  15. Influence of Traffic Vehicles Against Ground Fundamental Frequency Prediction using Ambient Vibration Technique

    Science.gov (United States)

    Kamarudin, A. F.; Noh, M. S. Md; Mokhatar, S. N.; Anuar, M. A. Mohd; Ibrahim, A.; Ibrahim, Z.; Daud, M. E.

    2018-04-01

    Ambient vibration (AV) technique is widely used nowadays for ground fundamental frequency prediction. This technique is easy, quick, non-destructive, less operator required and reliable result. The input motions of ambient vibration are originally collected from surrounding natural and artificial excitations. But, careful data acquisition controlled must be implemented to reduce the intrusion of short period noise that could imply the quality of frequency prediction of an investigated site. In this study, investigation on the primary noise intrusion under peak (morning, afternoon and evening) and off peak (early morning) traffic flows (only 8 meter from sensor to road shoulder) against the stability and quality of ground fundamental frequency prediction were carried out. None of specific standard is available for AV data acquisition and processing. Thus, some field and processing parameters recommended by previous studies and guideline were considered. Two units of 1 Hz tri-axial seismometer sensor were closely positioned in front of the main entrance Universiti Tun Hussein Onn Malaysia. 15 minutes of recording length were taken during peak and off peak periods of traffic flows. All passing vehicles were counted and grouped into four classes. Three components of ambient vibration time series recorded in the North-South: NS, East-West: EW and vertical: UD directions were automatically computed into Horizontal to Vertical Spectral Ratio (HVSR), by using open source software of GEOPSY for fundamental ground frequency, Fo determination. Single sharp peak pattern of HVSR curves have been obtained at peak frequencies between 1.33 to 1.38 Hz which classified under soft to dense soil classification. Even identical HVSR curves pattern with close frequencies prediction were obtained under both periods of AV measurement, however the total numbers of stable and quality windows selected for HVSR computation were significantly different but both have satisfied the requirement

  16. Geodesic acoustic eigenmode for tokamak equilibrium with maximum of local GAM frequency

    Energy Technology Data Exchange (ETDEWEB)

    Lakhin, V.P. [NRC “Kurchatov Institute”, Moscow (Russian Federation); Sorokina, E.A., E-mail: sorokina.ekaterina@gmail.com [NRC “Kurchatov Institute”, Moscow (Russian Federation); Peoples' Friendship University of Russia, Moscow (Russian Federation)

    2014-01-24

    The geodesic acoustic eigenmode for tokamak equilibrium with the maximum of local GAM frequency is found analytically in the frame of MHD model. The analysis is based on the asymptotic matching technique.

  17. Changes in speaking fundamental frequency characteristics with aging.

    Science.gov (United States)

    Nishio, Masaki; Niimi, Seiji

    2008-01-01

    Changes in speaking fundamental frequency (SFF) associated with aging were studied in a total of 374 healthy normal speakers (187 males and 187 females) from adolescent to older age groups. Participants were asked to read a sample passage aloud, and acoustic analysis was performed. The main results were as follows: (1) Males exhibited no significant trend for SFF changes in aging. However, a slight increase was observed in participants aged 70 years or older. (2) Females in their 30s and 40s showed obviously lower frequencies than those in their 20s. Across all age groups, including the 80s, SFF tended to decrease markedly in association with aging. (3) The degree of SFF change in association with aging was much larger in females than in males. In addition, reference intervals (mean +/- 1.96 SD) obtained for males and females in each age group are considered useful for clinical detection of abnormalities of SFF, as well as for detection of laryngeal diseases causing SFF abnormality. 2008 S. Karger AG, Basel.

  18. Discrimination of fundamental frequency of synthesized vowel sounds in a noise background

    NARCIS (Netherlands)

    Scheffers, M.T.M.

    1984-01-01

    An experiment was carried out, investigating the relationship between the just noticeable difference of fundamental frequency (jndf0) of three stationary synthesized vowel sounds in noise and the signal-to-noise ratio. To this end the S/N ratios were measured at which listeners could just

  19. YIN, a fundamental frequency estimator for speech and music

    Science.gov (United States)

    de Cheveigné, Alain; Kawahara, Hideki

    2002-04-01

    An algorithm is presented for the estimation of the fundamental frequency (F0) of speech or musical sounds. It is based on the well-known autocorrelation method with a number of modifications that combine to prevent errors. The algorithm has several desirable features. Error rates are about three times lower than the best competing methods, as evaluated over a database of speech recorded together with a laryngograph signal. There is no upper limit on the frequency search range, so the algorithm is suited for high-pitched voices and music. The algorithm is relatively simple and may be implemented efficiently and with low latency, and it involves few parameters that must be tuned. It is based on a signal model (periodic signal) that may be extended in several ways to handle various forms of aperiodicity that occur in particular applications. Finally, interesting parallels may be drawn with models of auditory processing.

  20. Maximum Entropy, Word-Frequency, Chinese Characters, and Multiple Meanings

    Science.gov (United States)

    Yan, Xiaoyong; Minnhagen, Petter

    2015-01-01

    The word-frequency distribution of a text written by an author is well accounted for by a maximum entropy distribution, the RGF (random group formation)-prediction. The RGF-distribution is completely determined by the a priori values of the total number of words in the text (M), the number of distinct words (N) and the number of repetitions of the most common word (kmax). It is here shown that this maximum entropy prediction also describes a text written in Chinese characters. In particular it is shown that although the same Chinese text written in words and Chinese characters have quite differently shaped distributions, they are nevertheless both well predicted by their respective three a priori characteristic values. It is pointed out that this is analogous to the change in the shape of the distribution when translating a given text to another language. Another consequence of the RGF-prediction is that taking a part of a long text will change the input parameters (M, N, kmax) and consequently also the shape of the frequency distribution. This is explicitly confirmed for texts written in Chinese characters. Since the RGF-prediction has no system-specific information beyond the three a priori values (M, N, kmax), any specific language characteristic has to be sought in systematic deviations from the RGF-prediction and the measured frequencies. One such systematic deviation is identified and, through a statistical information theoretical argument and an extended RGF-model, it is proposed that this deviation is caused by multiple meanings of Chinese characters. The effect is stronger for Chinese characters than for Chinese words. The relation between Zipf’s law, the Simon-model for texts and the present results are discussed. PMID:25955175

  1. Joint DOA and Fundamental Frequency Estimation Methods based on 2-D Filtering

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2010-01-01

    of the fundamental frequency and the DOA of spatio-temporarily sampled periodic signals. The first and simplest method is based on the 2-D periodogram, whereas the second method is a generalization of the 2-D Capon method. In the experimental part, both qualitative and quantitative measurements show that the proposed...

  2. Comparing the accuracy of perturbative and variational calculations for predicting fundamental vibrational frequencies of dihalomethanes

    Science.gov (United States)

    Krasnoshchekov, Sergey V.; Schutski, Roman S.; Craig, Norman C.; Sibaev, Marat; Crittenden, Deborah L.

    2018-02-01

    Three dihalogenated methane derivatives (CH2F2, CH2FCl, and CH2Cl2) were used as model systems to compare and assess the accuracy of two different approaches for predicting observed fundamental frequencies: canonical operator Van Vleck vibrational perturbation theory (CVPT) and vibrational configuration interaction (VCI). For convenience and consistency, both methods employ the Watson Hamiltonian in rectilinear normal coordinates, expanding the potential energy surface (PES) as a Taylor series about equilibrium and constructing the wavefunction from a harmonic oscillator product basis. At the highest levels of theory considered here, fourth-order CVPT and VCI in a harmonic oscillator basis with up to 10 quanta of vibrational excitation in conjunction with a 4-mode representation sextic force field (SFF-4MR) computed at MP2/cc-pVTZ with replacement CCSD(T)/aug-cc-pVQZ harmonic force constants, the agreement between computed fundamentals is closer to 0.3 cm-1 on average, with a maximum difference of 1.7 cm-1. The major remaining accuracy-limiting factors are the accuracy of the underlying electronic structure model, followed by the incompleteness of the PES expansion. Nonetheless, computed and experimental fundamentals agree to within 5 cm-1, with an average difference of 2 cm-1, confirming the utility and accuracy of both theoretical models. One exception to this rule is the formally IR-inactive but weakly allowed through Coriolis-coupling H-C-H out-of-plane twisting mode of dichloromethane, whose spectrum we therefore revisit and reassign. We also investigate convergence with respect to order of CVPT, VCI excitation level, and order of PES expansion, concluding that premature truncation substantially decreases accuracy, although VCI(6)/SFF-4MR results are still of acceptable accuracy, and some error cancellation is observed with CVPT2 using a quartic force field.

  3. Effects of Parkinson's Disease on Fundamental Frequency Variability in Running Speech.

    Science.gov (United States)

    Bowen, Leah K; Hands, Gabrielle L; Pradhan, Sujata; Stepp, Cara E

    2013-09-01

    In Parkinson's Disease (PD), qualitative speech changes such as decreased variation in pitch and loudness are common, but quantitative vocal changes are not well documented. The variability of fundamental frequency (F0) in 32 individuals (23 male) with PD both ON and OFF levodopa medication was compared with 32 age-matched healthy controls (23 male). Participants read a single paragraph and estimates of fundamental frequency (F0) variability were determined for the entire reading passage as well as for the first and last sentences of the passage separately. F0 variability was significantly increased in controls relative to both PD groups and PD patients showed significantly higher F0 variability while ON medication relative to OFF. No significant effect of group was seen in the change in F0 variability from the beginning to the end of the reading passage. Female speakers were found to have higher F0 variability than males. F0 variability was both significantly reduced in PD relative to controls and significantly increased in patients with PD during use of dopaminergic medications. F0 variability changes over the course of reading a paragraph may not be indicative of PD but rather dependent on non-disease factors such as the linguistic characteristics of the text.

  4. High-frequency harmonic imaging of the eye

    Science.gov (United States)

    Silverman, Ronald H.; Coleman, D. Jackson; Ketterling, Jeffrey A.; Lizzi, Frederic L.

    2005-04-01

    Purpose: Harmonic imaging has become a well-established technique for ultrasonic imaging at fundamental frequencies of 10 MHz or less. Ophthalmology has benefited from the use of fundamentals of 20 MHz to 50 MHz. Our aim was to explore the ability to generate harmonics for this frequency range, and to generate harmonic images of the eye. Methods: The presence of harmonics was determined in both water and bovine vitreous propagation media by pulse/echo and hydrophone at a series of increasing excitation pulse intensities and frequencies. Hydrophone measurements were made at the focal point and in the near- and far-fields of 20 MHz and 40 MHz transducers. Harmonic images of the anterior segment of the rabbit eye were obtained by a combination of analog filtering and digital post-processing. Results: Harmonics were generated nearly identically in both water and vitreous. Hydrophone measurements showed the maximum second harmonic to be -5 dB relative to the 35 MHz fundamental at the focus, while in pulse/echo the maximum harmonic amplitude was -15dB relative to the fundamental. Harmonics were absent in the near-field, but present in the far-field. Harmonic images of the eye showed improved resolution. Conclusion: Harmonics can be readily generated at very high frequencies, and at power levels compliant with FDA guidelines for ophthalmology. This technique may yield further improvements to the already impressive resolutions obtainable in this frequency range. Improved imaging of the macular region, in particular, may provide significant improvements in diagnosis of retinal disease.

  5. Fast LCMV-based Methods for Fundamental Frequency Estimation

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Glentis, George-Othon; Christensen, Mads Græsbøll

    2013-01-01

    peaks and require matrix inversions for each point in the search grid. In this paper, we therefore consider fast implementations of LCMV-based fundamental frequency estimators, exploiting the estimators' inherently low displacement rank of the used Toeplitz-like data covariance matrices, using...... with several orders of magnitude, but, as we show, further computational savings can be obtained by the adoption of an approximative IAA-based data covariance matrix estimator, reminiscent of the recently proposed Quasi-Newton IAA technique. Furthermore, it is shown how the considered pitch estimators can...... as such either the classic time domain averaging covariance matrix estimator, or, if aiming for an increased spectral resolution, the covariance matrix resulting from the application of the recent iterative adaptive approach (IAA). The proposed exact implementations reduce the required computational complexity...

  6. The effect of electric field maximum on the Rabi flopping and generated higher frequency spectra

    International Nuclear Information System (INIS)

    Niu Yueping; Cui Ni; Xiang Yang; Li Ruxin; Gong Shangqing; Xu Zhizhan

    2008-01-01

    We investigate the effect of the electric field maximum on the Rabi flopping and the generated higher frequency spectra properties by solving Maxwell-Bloch equations without invoking any standard approximations. It is found that the maximum of the electric field will lead to carrier-wave Rabi flopping (CWRF) through reversion dynamics which will be more evident when the applied field enters the sub-one-cycle regime. Therefore, under the interaction of sub-one-cycle pulses, the Rabi flopping follows the transient electric field tightly through the oscillation and reversion dynamics, which is in contrast to the conventional envelope Rabi flopping. Complete or incomplete population inversion can be realized through the control of the carrier-envelope phase (CEP). Furthermore, the generated higher frequency spectra will be changed from distinct to continuous or irregular with the variation of the CEP. Our results demonstrate that due to the evident maximum behavior of the electric field, pulses with different CEP give rise to different CWRFs, and then different degree of interferences lead to different higher frequency spectral features.

  7. Gender classification in children based on speech characteristics: using fundamental and formant frequencies of Malay vowels.

    Science.gov (United States)

    Zourmand, Alireza; Ting, Hua-Nong; Mirhassani, Seyed Mostafa

    2013-03-01

    Speech is one of the prevalent communication mediums for humans. Identifying the gender of a child speaker based on his/her speech is crucial in telecommunication and speech therapy. This article investigates the use of fundamental and formant frequencies from sustained vowel phonation to distinguish the gender of Malay children aged between 7 and 12 years. The Euclidean minimum distance and multilayer perceptron were used to classify the gender of 360 Malay children based on different combinations of fundamental and formant frequencies (F0, F1, F2, and F3). The Euclidean minimum distance with normalized frequency data achieved a classification accuracy of 79.44%, which was higher than that of the nonnormalized frequency data. Age-dependent modeling was used to improve the accuracy of gender classification. The Euclidean distance method obtained 84.17% based on the optimal classification accuracy for all age groups. The accuracy was further increased to 99.81% using multilayer perceptron based on mel-frequency cepstral coefficients. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  8. Multi-Channel Maximum Likelihood Pitch Estimation

    DEFF Research Database (Denmark)

    Christensen, Mads Græsbøll

    2012-01-01

    In this paper, a method for multi-channel pitch estimation is proposed. The method is a maximum likelihood estimator and is based on a parametric model where the signals in the various channels share the same fundamental frequency but can have different amplitudes, phases, and noise characteristics....... This essentially means that the model allows for different conditions in the various channels, like different signal-to-noise ratios, microphone characteristics and reverberation. Moreover, the method does not assume that a certain array structure is used but rather relies on a more general model and is hence...

  9. Frequência fundamental de crianças da cidade de Niterói Fundamental frequency for children in the municipality of Niterói

    Directory of Open Access Journals (Sweden)

    Tereza Cristina Andrade Schott

    2009-06-01

    Full Text Available OBJETIVO: medir a frequência fundamental de 122 crianças de seis a oito anos de idade, meninos e meninas, sem alterações vocais, avaliadas por meio da escala Rasat. MÉTODOS: a análise perceptivo-auditiva foi realizada através da escala RASAT e para a análise acústica computadorizada foi utilizado o programa de software Vox Metria, analisando-se a média da frequência fundamental de amostras da vogal [ε] sustentada. Participaram deste estudo 122 crianças, 58 meninos e 64 meninas com idade variando de seis a oito anos e 11 meses de idade do ensino fundamental, da Rede Municipal de Niterói-RJ, nascidos e residentes na cidade, pré-selecionadas através de um protocolo de triagem. RESULTADOS: os resultados obtidos neste estudo foram: frequência fundamental média de 239,60 Hz para as meninas e 237,17 Hz para os meninos, obtendo-se uma média geral de 238,44 Hz. CONCLUSÃO: conclui-se que os achados permitiram a comparação com resultados de pesquisas realizadas anteriormente, contribuindo com novos dados para a padronização da frequência fundamental das vozes infantis brasileiras.PURPOSE: to quantify the fundamental frequency in a group of 122 children - boys and girls, whose age varied from six to eight-year-old, who do not have vocal alterations. METHODS: an auditory-perceptive analysis took place by means of the RASAT scale; the computerized acoustic analysis was performed by using a software referred to as Vox Metria, where samples regarding the mean value for the fundamental frequency of the sustained vowel [ε] were analyzed. For this study, in which 122 children took part, 58 boys and 64 girls, with ages ranging from 6 to 8-year and 11 months. They were students from the Elementary Schools of the Municipal Education System of Niteroi-RJ. They were born and reside in this municipality and were pre-selected by means of a choice protocol. RESULTS: the results obtained in this study were 239.60 Hz for the girls and 237.17 Hz for

  10. Protonated Nitrous Oxide, NNOH(+): Fundamental Vibrational Frequencies and Spectroscopic Constants from Quartic Force Fields

    Science.gov (United States)

    Huang, Xinchuan; Fortenberry, Ryan C.; Lee, Timothy J.

    2013-01-01

    The interstellar presence of protonated nitrous oxide has been suspected for some time. Using established high-accuracy quantum chemical techniques, spectroscopic constants and fundamental vibrational frequencies are provided for the lower energy O-protonated isomer of this cation and its deuterated isotopologue. The vibrationally-averaged B0 and C0 rotational constants are within 6 MHz of their experimental values and the D(subJ) quartic distortion constants agree with experiment to within 3%. The known gas phase O-H stretch of NNOH(+) is 3330.91 cm(exp-1), and the vibrational configuration interaction computed result is 3330.9 cm(exp-1). Other spectroscopic constants are also provided, as are the rest of the fundamental vibrational frequencies for NNOH(+) and its deuterated isotopologue. This high-accuracy data should serve to better inform future observational or experimental studies of the rovibrational bands of protonated nitrous oxide in the ISM and the laboratory.

  11. Joint Spatio-Temporal Filtering Methods for DOA and Fundamental Frequency Estimation

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Christensen, Mads Græsbøll; Benesty, Jacob

    2015-01-01

    some attention in the community and is quite promising for several applications. The proposed methods are based on optimal, adaptive filters that leave the desired signal, having a certain DOA and fundamental frequency, undistorted and suppress everything else. The filtering methods simultaneously...... operate in space and time, whereby it is possible resolve cases that are otherwise problematic for pitch estimators or DOA estimators based on beamforming. Several special cases and improvements are considered, including a method for estimating the covariance matrix based on the recently proposed...

  12. Effects of Parkinson’s Disease on Fundamental Frequency Variability in Running Speech

    Science.gov (United States)

    Bowen, Leah K.; Hands, Gabrielle L.; Pradhan, Sujata; Stepp, Cara E.

    2013-01-01

    In Parkinson’s Disease (PD), qualitative speech changes such as decreased variation in pitch and loudness are common, but quantitative vocal changes are not well documented. The variability of fundamental frequency (F0) in 32 individuals (23 male) with PD both ON and OFF levodopa medication was compared with 32 age-matched healthy controls (23 male). Participants read a single paragraph and estimates of fundamental frequency (F0) variability were determined for the entire reading passage as well as for the first and last sentences of the passage separately. F0 variability was significantly increased in controls relative to both PD groups and PD patients showed significantly higher F0 variability while ON medication relative to OFF. No significant effect of group was seen in the change in F0 variability from the beginning to the end of the reading passage. Female speakers were found to have higher F0 variability than males. F0 variability was both significantly reduced in PD relative to controls and significantly increased in patients with PD during use of dopaminergic medications. F0 variability changes over the course of reading a paragraph may not be indicative of PD but rather dependent on non-disease factors such as the linguistic characteristics of the text. PMID:25838754

  13. A New High Frequency Injection Method Based on Duty Cycle Shifting without Maximum Voltage Magnitude Loss

    DEFF Research Database (Denmark)

    Wang, Dong; Lu, Kaiyuan; Rasmussen, Peter Omand

    2015-01-01

    The conventional high frequency signal injection method is to superimpose a high frequency voltage signal to the commanded stator voltage before space vector modulation. Therefore, the magnitude of the voltage used for machine torque production is limited. In this paper, a new high frequency...... amplitude. This may be utilized to develop new position estimation algorithm without involving the inductance in the medium to high speed range. As an application example, a developed inductance independent position estimation algorithm using the proposed high frequency injection method is applied to drive...... injection method, in which high frequency signal is generated by shifting the duty cycle between two neighboring switching periods, is proposed. This method allows injecting a high frequency signal at half of the switching frequency without the necessity to sacrifice the machine fundamental voltage...

  14. Frequency-Domain Maximum-Likelihood Estimation of High-Voltage Pulse Transformer Model Parameters

    CERN Document Server

    Aguglia, D; Martins, C.D.A.

    2014-01-01

    This paper presents an offline frequency-domain nonlinear and stochastic identification method for equivalent model parameter estimation of high-voltage pulse transformers. Such kinds of transformers are widely used in the pulsed-power domain, and the difficulty in deriving pulsed-power converter optimal control strategies is directly linked to the accuracy of the equivalent circuit parameters. These components require models which take into account electric fields energies represented by stray capacitance in the equivalent circuit. These capacitive elements must be accurately identified, since they greatly influence the general converter performances. A nonlinear frequency-based identification method, based on maximum-likelihood estimation, is presented, and a sensitivity analysis of the best experimental test to be considered is carried out. The procedure takes into account magnetic saturation and skin effects occurring in the windings during the frequency tests. The presented method is validated by experim...

  15. Modeling hemoglobin at optical frequency using the unconditionally stable fundamental ADI-FDTD method.

    Science.gov (United States)

    Heh, Ding Yu; Tan, Eng Leong

    2011-04-12

    This paper presents the modeling of hemoglobin at optical frequency (250 nm - 1000 nm) using the unconditionally stable fundamental alternating-direction-implicit finite-difference time-domain (FADI-FDTD) method. An accurate model based on complex conjugate pole-residue pairs is proposed to model the complex permittivity of hemoglobin at optical frequency. Two hemoglobin concentrations at 15 g/dL and 33 g/dL are considered. The model is then incorporated into the FADI-FDTD method for solving electromagnetic problems involving interaction of light with hemoglobin. The computation of transmission and reflection coefficients of a half space hemoglobin medium using the FADI-FDTD validates the accuracy of our model and method. The specific absorption rate (SAR) distribution of human capillary at optical frequency is also shown. While maintaining accuracy, the unconditionally stable FADI-FDTD method exhibits high efficiency in modeling hemoglobin.

  16. Correlation analysis of the physiological factors controlling fundamental voice frequency.

    Science.gov (United States)

    Atkinson, J E

    1978-01-01

    A technique has been developed to obtain a quantitative measure of correlation between electromyographic (EMG) activity of various laryngeal muscles, subglottal air pressure, and the fundamental frequency of vibration of the vocal folds (Fo). Data were collected and analyzed on one subject, a native speaker of American English. The results show that an analysis of this type can provide a useful measure of correlation between the physiological and acoustical events in speech and, furthermore, can yield detailed insights into the organization and nature of the speech production process. In particular, based on these results, a model is suggested of Fo control involving laryngeal state functions that seems to agree with present knowledge of laryngeal control and experimental evidence.

  17. A Study of the Effect of Emotional State upon the Variation of the Fundamental Frequency of a Speaker

    Directory of Open Access Journals (Sweden)

    Marius Vasile GHIURCAU

    2010-01-01

    Full Text Available Telephone banking or brokering, building accesssystems or forensics are some of the areas in which speakerrecognition is continuously developing. Fundamental frequencyrepresents an important speech feature used in theseapplications. In this paper we present a study of the effect ofemotional state of a speaker upon the variation of thefundamental frequency of the speech signal. Human beings arequite frequently overwhelmed by various emotions and most ofthe time one can not really control these emotional states. Forthe purpose of our work we have used the Berlin emotionalspeech database which contains utterances of 10 speakers indifferent emotional situations: happy, angry, fearful, bored andneutral. The mean fundamental frequency and also the standarddeviation for every speaker in all the emotional states werecomputed. The results show a very strong influence of theemotional state upon frequency variation.

  18. 2-Step Maximum Likelihood Channel Estimation for Multicode DS-CDMA with Frequency-Domain Equalization

    Science.gov (United States)

    Kojima, Yohei; Takeda, Kazuaki; Adachi, Fumiyuki

    Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can provide better downlink bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA) than the conventional rake combining in a frequency-selective fading channel. FDE requires accurate channel estimation. In this paper, we propose a new 2-step maximum likelihood channel estimation (MLCE) for DS-CDMA with FDE in a very slow frequency-selective fading environment. The 1st step uses the conventional pilot-assisted MMSE-CE and the 2nd step carries out the MLCE using decision feedback from the 1st step. The BER performance improvement achieved by 2-step MLCE over pilot assisted MMSE-CE is confirmed by computer simulation.

  19. Measurement of the Maximum Frequency of Electroglottographic Fluctuations in the Expiration Phase of Volitional Cough as a Functional Test for Cough Efficiency.

    Science.gov (United States)

    Iwahashi, Toshihiko; Ogawa, Makoto; Hosokawa, Kiyohito; Kato, Chieri; Inohara, Hidenori

    2017-10-01

    The hypotheses of the present study were that the maximum frequency of fluctuation of electroglottographic (EGG) signals in the expiration phase of volitional cough (VC) reflects the cough efficiency and that this EGG parameter is affected by impaired laryngeal closure, expiratory effort strength, and gender. For 20 normal healthy adults and 20 patients diagnosed with unilateral vocal fold paralysis (UVFP), each participant was fitted with EGG electrodes on the neck, had a transnasal laryngo-fiberscope inserted, and was asked to perform weak/strong VC tasks while EGG signals and a high-speed digital image of the larynx were recorded. The maximum frequency was calculated in the EGG fluctuation region coinciding with vigorous vocal fold vibration in the laryngeal HSDIs. In addition, each participant underwent spirometry for measurement of three aerodynamic parameters, including peak expiratory air flow (PEAF), during weak/strong VC tasks. Significant differences were found for both maximum EGG frequency and PEAF between the healthy and UVFP groups and between the weak and strong VC tasks. Among the three cough aerodynamic parameters, PEAF showed the highest positive correlation with the maximum EGG frequency. The correlation coefficients between the maximum EGG frequency and PEAF recorded simultaneously were 0.574 for the whole group, and 0.782/0.717/0.823/0.688 for the male/female/male-healthy/male-UVFP subgroups, respectively. Consequently, the maximum EGG frequency measured in the expiration phase of VC was shown to reflect the velocity of expiratory airflow to some extent and was suggested to be affected by vocal fold physical properties, glottal closure condition, and the expiratory function.

  20. Radio Frequency Transistors Using Aligned Semiconducting Carbon Nanotubes with Current-Gain Cutoff Frequency and Maximum Oscillation Frequency Simultaneously Greater than 70 GHz.

    Science.gov (United States)

    Cao, Yu; Brady, Gerald J; Gui, Hui; Rutherglen, Chris; Arnold, Michael S; Zhou, Chongwu

    2016-07-26

    In this paper, we report record radio frequency (RF) performance of carbon nanotube transistors based on combined use of a self-aligned T-shape gate structure, and well-aligned, high-semiconducting-purity, high-density polyfluorene-sorted semiconducting carbon nanotubes, which were deposited using dose-controlled, floating evaporative self-assembly method. These transistors show outstanding direct current (DC) performance with on-current density of 350 μA/μm, transconductance as high as 310 μS/μm, and superior current saturation with normalized output resistance greater than 100 kΩ·μm. These transistors create a record as carbon nanotube RF transistors that demonstrate both the current-gain cutoff frequency (ft) and the maximum oscillation frequency (fmax) greater than 70 GHz. Furthermore, these transistors exhibit good linearity performance with 1 dB gain compression point (P1dB) of 14 dBm and input third-order intercept point (IIP3) of 22 dBm. Our study advances state-of-the-art of carbon nanotube RF electronics, which have the potential to be made flexible and may find broad applications for signal amplification, wireless communication, and wearable/flexible electronics.

  1. Evaluating Annual Maximum and Partial Duration Series for Estimating Frequency of Small Magnitude Floods

    Directory of Open Access Journals (Sweden)

    Fazlul Karim

    2017-06-01

    Full Text Available Understanding the nature of frequent floods is important for characterising channel morphology, riparian and aquatic habitat, and informing river restoration efforts. This paper presents results from an analysis on frequency estimates of low magnitude floods using the annual maximum and partial series data compared to actual flood series. Five frequency distribution models were fitted to data from 24 gauging stations in the Great Barrier Reef (GBR lagoon catchments in north-eastern Australia. Based on the goodness of fit test, Generalised Extreme Value, Generalised Pareto and Log Pearson Type 3 models were used to estimate flood frequencies across the study region. Results suggest frequency estimates based on a partial series are better, compared to an annual series, for small to medium floods, while both methods produce similar results for large floods. Although both methods converge at a higher recurrence interval, the convergence recurrence interval varies between catchments. Results also suggest frequency estimates vary slightly between two or more partial series, depending on flood threshold, and the differences are large for the catchments that experience less frequent floods. While a partial series produces better frequency estimates, it can underestimate or overestimate the frequency if the flood threshold differs largely compared to bankfull discharge. These results have significant implications in calculating the dependency of floodplain ecosystems on the frequency of flooding and their subsequent management.

  2. Simulation of a Smith-Purcell free-electron laser with sidewalls: Copious emission at the fundamental frequency

    International Nuclear Information System (INIS)

    Donohue, J. T.; Gardelle, J.

    2011-01-01

    The two-dimensional theory of the Smith-Purcell free-electron laser of Andrews and Brau [H. L. Andrews and C. A. Brau, Phys. Rev. ST Accel. Beams 7, 070701 (2004)] predicts that coherent Smith-Purcell radiation can occur only at harmonics of the frequency of the evanescent wave that is resonant with the beam. A particle-in-cell simulation shows that in a three-dimensional context, where the lamellar grating has sidewalls, coherent Smith-Purcell radiation can be copiously emitted at the fundamental frequency, for a well-defined range of beam energy.

  3. Hyperfine-resolved transition frequency list of fundamental vibration bands of H35Cl and H37Cl

    Science.gov (United States)

    Iwakuni, Kana; Sera, Hideyuki; Abe, Masashi; Sasada, Hiroyuki

    2014-12-01

    Sub-Doppler resolution spectroscopy of the fundamental vibration bands of H35Cl and H37Cl has been carried out from 87.1 to 89.9 THz. We have determined the absolute transition frequencies of the hyperfine-resolved R(0) to R(4) transitions with a typical uncertainty of 10 kHz. We have also yielded six molecular constants for each isotopomer in the vibrational excited state, which reproduce the determined frequencies with a standard deviation of about 10 kHz.

  4. Direct comparison of phase-sensitive vibrational sum frequency generation with maximum entropy method: case study of water.

    Science.gov (United States)

    de Beer, Alex G F; Samson, Jean-Sebastièn; Hua, Wei; Huang, Zishuai; Chen, Xiangke; Allen, Heather C; Roke, Sylvie

    2011-12-14

    We present a direct comparison of phase sensitive sum-frequency generation experiments with phase reconstruction obtained by the maximum entropy method. We show that both methods lead to the same complex spectrum. Furthermore, we discuss the strengths and weaknesses of each of these methods, analyzing possible sources of experimental and analytical errors. A simulation program for maximum entropy phase reconstruction is available at: http://lbp.epfl.ch/. © 2011 American Institute of Physics

  5. High-efficiency frequency doubling of continuous-wave laser light.

    Science.gov (United States)

    Ast, Stefan; Nia, Ramon Moghadas; Schönbeck, Axel; Lastzka, Nico; Steinlechner, Jessica; Eberle, Tobias; Mehmet, Moritz; Steinlechner, Sebastian; Schnabel, Roman

    2011-09-01

    We report on the observation of high-efficiency frequency doubling of 1550 nm continuous-wave laser light in a nonlinear cavity containing a periodically poled potassium titanyl phosphate crystal (PPKTP). The fundamental field had a power of 1.10 W and was converted into 1.05 W at 775 nm, yielding a total external conversion efficiency of 95±1%. The latter value is based on the measured depletion of the fundamental field being consistent with the absolute values derived from numerical simulations. According to our model, the conversion efficiency achieved was limited by the nonperfect mode matching into the nonlinear cavity and by the nonperfect impedance matching for the maximum input power available. Our result shows that cavity-assisted frequency conversion based on PPKTP is well suited for low-decoherence frequency conversion of quantum states of light.

  6. Effects of different strength training frequencies on maximum strength, body composition and functional capacity in healthy older individuals.

    Science.gov (United States)

    Turpela, Mari; Häkkinen, Keijo; Haff, Guy Gregory; Walker, Simon

    2017-11-01

    There is controversy in the literature regarding the dose-response relationship of strength training in healthy older participants. The present study determined training frequency effects on maximum strength, muscle mass and functional capacity over 6months following an initial 3-month preparatory strength training period. One-hundred and six 64-75year old volunteers were randomly assigned to one of four groups; performing strength training one (EX1), two (EX2), or three (EX3) times per week and a non-training control (CON) group. Whole-body strength training was performed using 2-5 sets and 4-12 repetitions per exercise and 7-9 exercises per session. Before and after the intervention, maximum dynamic leg press (1-RM) and isometric knee extensor and plantarflexor strength, body composition and quadriceps cross-sectional area, as well as functional capacity (maximum 7.5m forward and backward walking speed, timed-up-and-go test, loaded 10-stair climb test) were measured. All experimental groups increased leg press 1-RM more than CON (EX1: 3±8%, EX2: 6±6%, EX3: 10±8%, CON: -3±6%, Ptraining frequency would induce greater benefit to maximum walking speed (i.e. functional capacity) despite a clear dose-response in dynamic 1-RM strength, at least when predominantly using machine weight-training. It appears that beneficial functional capacity improvements can be achieved through low frequency training (i.e. 1-2 times per week) in previously untrained healthy older participants. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Examining explanations for fundamental frequency's contribution to speech intelligibility in noise

    Science.gov (United States)

    Schlauch, Robert S.; Miller, Sharon E.; Watson, Peter J.

    2005-09-01

    Laures and Weismer [JSLHR, 42, 1148 (1999)] reported that speech with natural variation in fundamental frequency (F0) is more intelligible in noise than speech with a flattened F0 contour. Cognitive-linguistic based explanations have been offered to account for this drop in intelligibility for the flattened condition, but a lower-level mechanism related to auditory streaming may be responsible. Numerous psychoacoustic studies have demonstrated that modulating a tone enables a listener to segregate it from background sounds. To test these rival hypotheses, speech recognition in noise was measured for sentences with six different F0 contours: unmodified, flattened at the mean, natural but exaggerated, reversed, and frequency modulated (rates of 2.5 and 5.0 Hz). The 180 stimulus sentences were produced by five talkers (30 sentences per condition). Speech recognition for fifteen listeners replicate earlier findings showing that flattening the F0 contour results in a roughly 10% reduction in recognition of key words compared with the natural condition. Although the exaggerated condition produced results comparable to those of the flattened condition, the other conditions with unnatural F0 contours all yielded significantly poorer performance than the flattened condition. These results support the cognitive, linguistic-based explanations for the reduction in performance.

  8. Elastic-plastic response characteristics during frequency nonstationary waves

    International Nuclear Information System (INIS)

    Miyama, T.; Kanda, J.; Iwasaki, R.; Sunohara, H.

    1987-01-01

    The purpose of this paper is to study fundamental effects of the frequency nonstationarity on the inelastic responses. First, the inelastic response characteristics are examined by applying stationary waves. Then simple representation of nonstationary characteristics is considered to general nonstationary input. The effects for frequency nonstationary response are summarized for inelastic systems. The inelastic response characteristics under white noise and simple frequency nonstationary wave were investigated, and conclusions can be summarized as follows. 1) The maximum response values for both BL model and OO model corresponds fairly well with those estimated from the energy constant law, even when R is small. For the OO model, the maximum displacement response forms a unique curve except for very small R. 2) The plastic deformation for the BL model is affected by wide frequency components, as R decreases. The plastic deformation for the OO model can be determined from the last stiffness. 3). The inelastic response of the BL model is considerably affected by the frequency nonstationarity of the input motion, while the response is less affected by the nonstationarity for OO model. (orig./HP)

  9. Vocal fold elasticity of the Rocky Mountain elk (Cervus elaphus nelsoni) – producing high fundamental frequency vocalization with a very long vocal fold

    OpenAIRE

    Riede, Tobias; Titze, Ingo R.

    2008-01-01

    The vocal folds of male Rocky Mountain elk (Cervus elaphus nelsoni) are about 3 cm long. If fundamental frequency were to be predicted by a simple vibrating string formula, as is often done for the human larynx, such long vocal folds would bear enormous stress to produce the species-specific mating call with an average fundamental frequency of 1 kHz. Predictions would be closer to 50 Hz. Vocal fold histology revealed the presence of a large vocal ligament between the vocal fold epithelium and...

  10. Spatiotemporal frequency characteristics of cerebral oscillations during the perception of fundamental frequency contour changes in one-syllable intonation.

    Science.gov (United States)

    Ueno, Sanae; Okumura, Eiichi; Remijn, Gerard B; Yoshimura, Yuko; Kikuchi, Mitsuru; Shitamichi, Kiyomi; Nagao, Kikuko; Mochiduki, Masayuki; Haruta, Yasuhiro; Hayashi, Norio; Munesue, Toshio; Tsubokawa, Tsunehisa; Oi, Manabu; Nakatani, Hideo; Higashida, Haruhiro; Minabe, Yoshio

    2012-05-02

    Accurate perception of fundamental frequency (F0) contour changes in the human voice is important for understanding a speaker's intonation, and consequently also his/her attitude. In this study, we investigated the neural processes involved in the perception of F0 contour changes in the Japanese one-syllable interjection "ne" in 21 native-Japanese listeners. A passive oddball paradigm was applied in which "ne" with a high falling F0 contour, used when urging a reaction from the listener, was randomly presented as a rare deviant among a frequent "ne" syllable with a flat F0 contour (i.e., meaningless intonation). We applied an adaptive spatial filtering method to the neuromagnetic time course recorded by whole-head magnetoencephalography (MEG) and estimated the spatiotemporal frequency dynamics of event-related cerebral oscillatory changes in the oddball paradigm. Our results demonstrated a significant elevation of beta band event-related desynchronization (ERD) in the right temporal and frontal areas, in time windows from 100 to 300 and from 300 to 500 ms after the onset of deviant stimuli (high falling F0 contour). This is the first study to reveal detailed spatiotemporal frequency characteristics of cerebral oscillations during the perception of intonational (not lexical) F0 contour changes in the human voice. The results further confirmed that the right hemisphere is associated with perception of intonational F0 contour information in the human voice, especially in early time windows. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2008-01-01

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

  12. Photovoltaic High-Frequency Pulse Charger for Lead-Acid Battery under Maximum Power Point Tracking

    Directory of Open Access Journals (Sweden)

    Hung-I. Hsieh

    2013-01-01

    Full Text Available A photovoltaic pulse charger (PV-PC using high-frequency pulse train for charging lead-acid battery (LAB is proposed not only to explore the charging behavior with maximum power point tracking (MPPT but also to delay sulfating crystallization on the electrode pores of the LAB to prolong the battery life, which is achieved due to a brief pulse break between adjacent pulses that refreshes the discharging of LAB. Maximum energy transfer between the PV module and a boost current converter (BCC is modeled to maximize the charging energy for LAB under different solar insolation. A duty control, guided by a power-increment-aided incremental-conductance MPPT (PI-INC MPPT, is implemented to the BCC that operates at maximum power point (MPP against the random insolation. A 250 W PV-PC system for charging a four-in-series LAB (48 Vdc is examined. The charging behavior of the PV-PC system in comparison with that of CC-CV charger is studied. Four scenarios of charging statuses of PV-BC system under different solar insolation changes are investigated and compared with that using INC MPPT.

  13. Fundamental Frequency and Direction-of-Arrival Estimation for Multichannel Speech Enhancement

    DEFF Research Database (Denmark)

    Karimian-Azari, Sam

    Audio systems receive the speech signals of interest usually in the presence of noise. The noise has profound impacts on the quality and intelligibility of the speech signals, and it is therefore clear that the noisy signals must be cleaned up before being played back, stored, or analyzed. We can...... estimate the speech signal of interest from the noisy signals using a priori knowledge about it. A human speech signal is broadband and consists of both voiced and unvoiced parts. The voiced part is quasi-periodic with a time-varying fundamental frequency (or pitch as it is commonly referred to). We...... their time differences which eventually may further reduce the effects of noise. This thesis introduces a number of principles and methods to estimate periodic signals in noisy environments with application to multichannel speech enhancement. We propose model-based signal enhancement concerning the model...

  14. Estudo da freqüência fundamental da voz de idosas portadoras de diferentes graus de perda auditiva Study of the fundamental frequency in elderly women with hearing loss

    Directory of Open Access Journals (Sweden)

    Giovana dos Santos Baraldi

    2007-06-01

    Full Text Available A deficiência auditiva, dentre outros, é um dos distúrbios mais referidos pela população idosa. Sabe-se que o sistema de feedback auditivo é primordial para o monitoramento dos parâmetros vocais, como a freqüência fundamenta. OBJETIVO: Correlacionar a audição e os valores de F0 (freqüência fundamental da voz de idosas portadores de diferentes graus de sensibilidade auditiva. FORMA DO ESTUDO: Transversal descritivo. MATERIAL E MÉTODOS: Amostra de 30 idosas, idades média de 76,23, portadoras de audição normal ou perda auditiva neurossensorial descendente simétrica. Foram submetidas a anamnese, avaliação auditiva (audiometria tonal limiar, IPRF e imitanciometria e avaliação vocal. Os resultados de ambas as avaliações foram correlacionados. RESULTADOS: A F0 da produção vocal de idosas com perda leve (144,44 foi significantemente menor que para perda moderada (160,3, moderadamente severa (188,23 e severa (201,27, tanto utilizando a classificação de grau da perda auditiva para freqüências baixas como altas. CONCLUSÃO: Quanto mais elevado o grau da perda auditiva, maior o valor de freqüência fundamental encontrado.Increased life expectancy raises demands for special attention for the elderly population; speech, language and hearing science deals with their communication disorders. Hearing loss is a common disorder affecting this age group. It is known that the auditory feedback system is essential to human vocalizing, as it organizes voice production. AIM: To assess and correlate the hearing system and the Fundamental Frequency (F0 of women who have variable degrees of sensorineural hearing loss. MATERIAL AND METHOD: a cross-sectional descriptive study. 30 women with a mean age of 75.95 (SD = 7,41 were included. Inclusion criteria were: symmetric sensorineural hearing loss, a high-frequency sloping configuration, and a type A tympanogram. Subjects underwent Pure Tone Audiometry, a Word Recognition Test, Tympanometry

  15. Is the speaking fundamental frequency in females related to body height?

    Science.gov (United States)

    Barsties, Ben; Verfaillie, Rudi; Dicks, Peter; Maryn, Youri

    2016-01-01

    The aim of the study was to determine the impact of body height on speaking fundamental frequency (SF0) while controlling for as many as possible influencing factors such as habits, biophysical conditions, medication, diseases, and others. Fifty-eight females were analyzed during spontaneous speech (i.e. explaining driving directions or a cooking recipe) of at least 60 seconds at comfortable pitch and loudness. The subjects showed a moderate negative and significant correlation between body height and SF0 (r = -0.40, P = 0.002). With r(2) = 0.16, however, a reasonable portion (16%) of the variance in SF0 is explained by the variance in body height. In comparison with other factors for which a correlation with SF0 was mentioned in literature (hypothyrodism, hemodialysis, auditory-maleness after female-to-male transsexualism, body weight, body mass index, and body fat), body height accounted for most of the proportion of SF0 in females. It is therefore possible to validate body height as a factor to account for in clinical F0 measurement.

  16. Glottal volume velocity waveform characteristics in subjects with and without vocal training, related to gender, sound intensity, fundamental frequency, and age

    NARCIS (Netherlands)

    Sulter, AM; Wit, HP

    Glottal volume velocity waveform characteristics of 224 subjects, categorized in four groups according to gender and vocal training, were determined, and their relations to sound-pressure level, fundamental frequency, intra-oral pressure, and age were analyzed. Subjects phonated at three intensity

  17. Glottal volume velocity waveform characteristics in subjects with and without vocal training, related to gender, sound intensity, fundamental frequency, and age

    NARCIS (Netherlands)

    Sulter, AM; Wit, HP

    1996-01-01

    Glottal volume velocity waveform characteristics of 224 subjects, categorized in four groups according to gender and vocal training, were determined, and their relations to sound-pressure level, fundamental frequency, intra-oral pressure, and age were analyzed. Subjects phonated at three intensity

  18. [Polish guidelines of 2001 for maximum admissible intensities in high frequency EMF versus European Union recommendations].

    Science.gov (United States)

    Aniołczyk, Halina

    2003-01-01

    In 1999, a draft of amendments to maximum admissible intensities (MAI) of electromagnetic fields (0 Hz-300 GHz) was prepared by Professor H. Korniewicz of the Central Institute for Labour Protection, Warsaw, in cooperation with the Nofer Institute of Occupational Medicine, Łódź (radio- and microwaves) and the Military Institute of Hygiene and Epidemiology, Warsaw (pulse radiation). Before 2000, the development of the national MAI guidelines for the frequency range of 0.1 MHz-300 GHz was based on the knowledge of biological and health effects of EMF exposure available on the turn of the 1960s. A current basis for establishing the MAI international standards is a well-documented thermal effect measured by the value of a specific absorption rate (SAR), whereas the effects of resonant absorption imposes the nature of the functional dependency on EMF frequency. The Russian standards, already thoroughly analyzed, still take so-called non-thermal effects and the conception of energetic load for a work-shift with its progressive averaging (see hazardous zone in Polish guidelines) as a basis for setting maximum admissible intensities. The World Health Organization recommends a harmonization of the EMF protection guidelines, existing in different countries, with the guidelines of the International Commission for Non-Ionizing Radiation Protection (ICNIRP), and its position is supported by the European Union.

  19. Fundamental gravitational limitations to quantum computing

    International Nuclear Information System (INIS)

    Gambini, R.; Porto, A.; Pullin, J.

    2006-01-01

    Lloyd has considered the ultimate limitations the fundamental laws of physics place on quantum computers. He concludes in particular that for an 'ultimate laptop' (a computer of one liter of volume and one kilogram of mass) the maximum number of operations per second is bounded by 10 51 . The limit is derived considering ordinary quantum mechanics. Here we consider additional limits that are placed by quantum gravity ideas, namely the use of a relational notion of time and fundamental gravitational limits that exist on time measurements. We then particularize for the case of an ultimate laptop and show that the maximum number of operations is further constrained to 10 47 per second. (authors)

  20. Masking release with changing fundamental frequency: Electric acoustic stimulation resembles normal hearing subjects.

    Science.gov (United States)

    Auinger, Alice Barbara; Riss, Dominik; Liepins, Rudolfs; Rader, Tobias; Keck, Tilman; Keintzel, Thomas; Kaider, Alexandra; Baumgartner, Wolf-Dieter; Gstoettner, Wolfgang; Arnoldner, Christoph

    2017-07-01

    It has been shown that patients with electric acoustic stimulation (EAS) perform better in noisy environments than patients with a cochlear implant (CI). One reason for this could be the preserved access to acoustic low-frequency cues including the fundamental frequency (F0). Therefore, our primary aim was to investigate whether users of EAS experience a release from masking with increasing F0 difference between target talker and masking talker. The study comprised 29 patients and consisted of three groups of subjects: EAS users, CI users and normal-hearing listeners (NH). All CI and EAS users were implanted with a MED-EL cochlear implant and had at least 12 months of experience with the implant. Speech perception was assessed with the Oldenburg sentence test (OlSa) using one sentence from the test corpus as speech masker. The F0 in this masking sentence was shifted upwards by 4, 8, or 12 semitones. For each of these masker conditions the speech reception threshold (SRT) was assessed by adaptively varying the masker level while presenting the target sentences at a fixed level. A statistically significant improvement in speech perception was found for increasing difference in F0 between target sentence and masker sentence in EAS users (p = 0.038) and in NH listeners (p = 0.003). In CI users (classic CI or EAS users with electrical stimulation only) speech perception was independent from differences in F0 between target and masker. A release from masking with increasing difference in F0 between target and masking speech was only observed in listeners and configurations in which the low-frequency region was presented acoustically. Thus, the speech information contained in the low frequencies seems to be crucial for allowing listeners to separate multiple sources. By combining acoustic and electric information, EAS users even manage tasks as complicated as segregating the audio streams from multiple talkers. Preserving the natural code, like fine-structure cues in

  1. Frequency mixing in boron carbide laser ablation plasmas

    Science.gov (United States)

    Oujja, M.; Benítez-Cañete, A.; Sanz, M.; Lopez-Quintas, I.; Martín, M.; de Nalda, R.; Castillejo, M.

    2015-05-01

    Nonlinear frequency mixing induced by a bichromatic field (1064 nm + 532 nm obtained from a Q-switched Nd:YAG laser) in a boron carbide (B4C) plasma generated through laser ablation under vacuum is explored. A UV beam at the frequency of the fourth harmonic of the fundamental frequency (266 nm) was generated. The dependence of the efficiency of the process as function of the intensities of the driving lasers differs from the expected behavior for four-wave mixing, and point toward a six-wave mixing process. The frequency mixing process was strongly favored for parallel polarizations of the two driving beams. Through spatiotemporal mapping, the conditions for maximum efficiency were found for a significant delay from the ablation event (200 ns), when the medium is expected to be a low-ionized plasma. No late components of the harmonic signal were detected, indicating a largely atomized medium.

  2. Fundamentals of Acoustics. Psychoacoustics and Hearing. Acoustical Measurements

    Science.gov (United States)

    Begault, Durand R.; Ahumada, Al (Technical Monitor)

    1997-01-01

    These are 3 chapters that will appear in a book titled "Building Acoustical Design", edited by Charles Salter. They are designed to introduce the reader to fundamental concepts of acoustics, particularly as they relate to the built environment. "Fundamentals of Acoustics" reviews basic concepts of sound waveform frequency, pressure, and phase. "Psychoacoustics and Hearing" discusses the human interpretation sound pressure as loudness, particularly as a function of frequency. "Acoustic Measurements" gives a simple overview of the time and frequency weightings for sound pressure measurements that are used in acoustical work.

  3. Numerical analysis of effects of transglottal pressure change on fundamental frequency of phonation.

    Science.gov (United States)

    Deguchi, Shinji; Matsuzaki, Yuji; Ikeda, Tadashige

    2007-02-01

    In humans, a decrease in transglottal pressure (Pt) causes an increase in the fundamental frequency of phonation (F0) only at a specific voice pitch within the modal register, the mechanism of which remains unclear. In the present study, numerical analyses were performed to investigate the mechanism of the voice pitch-dependent positive change of F0 due to Pt decrease. The airflow and the airway, including the vocal folds, were modeled in terms of mechanics of fluid and structure. Simulations of phonation using the numerical model indicated that Pt affects both the average position and the average amplitude magnitude of vocal fold self-excited oscillation in a non-monotonous manner. This effect results in voice pitch-dependent responses of F0 to Pt decreases, including the positive response of F0 as actually observed in humans. The findings of the present study highlight the importance of considering self-excited oscillation of the vocal folds in elucidation of the phonation mechanism.

  4. Can temporal fine structure represent the fundamental frequency of unresolved harmonics?

    Science.gov (United States)

    Oxenham, Andrew J; Micheyl, Christophe; Keebler, Michael V

    2009-04-01

    At least two modes of pitch perception exist: in one, the fundamental frequency (F0) of harmonic complex tones is estimated using the temporal fine structure (TFS) of individual low-order resolved harmonics; in the other, F0 is derived from the temporal envelope of high-order unresolved harmonics that interact in the auditory periphery. Pitch is typically more accurate in the former than in the latter mode. Another possibility is that pitch can sometimes be coded via the TFS from unresolved harmonics. A recent study supporting this third possibility [Moore et al. (2006a). J. Acoust. Soc. Am. 119, 480-490] based its conclusion on a condition where phase interaction effects (implying unresolved harmonics) accompanied accurate F0 discrimination (implying TFS processing). The present study tests whether these results were influenced by audible distortion products. Experiment 1 replicated the original results, obtained using a low-level background noise. However, experiments 2-4 found no evidence for the use of TFS cues with unresolved harmonics when the background noise level was raised, or the stimulus level was lowered, to render distortion inaudible. Experiment 5 measured the presence and phase dependence of audible distortion products. The results provide no evidence that TFS cues are used to code the F0 of unresolved harmonics.

  5. Detecting vocal fatigue in student singers using acoustic measures of mean fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio

    Science.gov (United States)

    Sisakun, Siphan

    2000-12-01

    The purpose of this study is to explore the ability of four acoustic parameters, mean fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio, to detect vocal fatigue in student singers. The participants are 15 voice students, who perform two distinct tasks, data collection task and vocal fatiguing task. The data collection task includes the sustained vowel /a/, reading a standard passage, and self-rate on a vocal fatigue form. The vocal fatiguing task is the vocal practice of musical scores for a total of 45 minutes. The four acoustic parameters are extracted using the software EZVoicePlus. The data analyses are performed to answer eight research questions. The first four questions relate to correlations of the self-rating scale and each of the four parameters. The next four research questions relate to differences in the parameters over time using one-factor repeated measures analysis of variance (ANOVA). The result yields a proposed acoustic profile of vocal fatigue in student singers. This profile is characterized by increased fundamental frequency; slightly decreased jitter; slightly decreased shimmer; and slightly increased harmonics-to-noise ratio. The proposed profile requires further investigation.

  6. Interpretations of Frequency Domain Analyses of Neural Entrainment: Periodicity, Fundamental Frequency, and Harmonics.

    Science.gov (United States)

    Zhou, Hong; Melloni, Lucia; Poeppel, David; Ding, Nai

    2016-01-01

    Brain activity can follow the rhythms of dynamic sensory stimuli, such as speech and music, a phenomenon called neural entrainment. It has been hypothesized that low-frequency neural entrainment in the neural delta and theta bands provides a potential mechanism to represent and integrate temporal information. Low-frequency neural entrainment is often studied using periodically changing stimuli and is analyzed in the frequency domain using the Fourier analysis. The Fourier analysis decomposes a periodic signal into harmonically related sinusoids. However, it is not intuitive how these harmonically related components are related to the response waveform. Here, we explain the interpretation of response harmonics, with a special focus on very low-frequency neural entrainment near 1 Hz. It is illustrated why neural responses repeating at f Hz do not necessarily generate any neural response at f Hz in the Fourier spectrum. A strong neural response at f Hz indicates that the time scales of the neural response waveform within each cycle match the time scales of the stimulus rhythm. Therefore, neural entrainment at very low frequency implies not only that the neural response repeats at f Hz but also that each period of the neural response is a slow wave matching the time scale of a f Hz sinusoid.

  7. Fundamental-frequency and load-varying thermal cycles effects on lifetime estimation of DFIG power converter

    DEFF Research Database (Denmark)

    Zhang, G.; Zhou, D.; Yang, J.

    2017-01-01

    In respect to a Doubly-Fed Induction Generator (DFIG) system, its corresponding time scale varies from microsecond level of power semiconductor switching to second level of the mechanical response. In order to map annual thermal profile of the power semiconductors, different approaches have been ...... adopted to handle the fundamental-frequency thermal cycles and load-varying thermal cycles. Their effects on lifetime estimation of the power device in the Back-to-Back (BTB) power converter are evaluated.......In respect to a Doubly-Fed Induction Generator (DFIG) system, its corresponding time scale varies from microsecond level of power semiconductor switching to second level of the mechanical response. In order to map annual thermal profile of the power semiconductors, different approaches have been...

  8. Gate-Recessed AlGaN/GaN MOSHEMTs with the Maximum Oscillation Frequency Exceeding 120 GHz on Sapphire Substrates

    International Nuclear Information System (INIS)

    Kong Xin; Wei Ke; Liu Guo-Guo; Liu Xin-Yu

    2012-01-01

    Gate-recessed AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs) on sapphire substrates are fabricated. The devices with a gate length of 160 nm and a gate periphery of 2 × 75 μm exhibit two orders of magnitude reduction in gate leakage current and enhanced off-state breakdown characteristics, compared with conventional HEMTs. Furthermore, the extrinsic transconductance of an MOSHEMT is 237.2 mS/mm, only 7% lower than that of Schottky-gate HEMT. An extrinsic current gain cutoff frequency f T of 65 GHz and a maximum oscillation frequency f max of 123 GHz are deduced from rf small signal measurements. The high f max demonstrates that gate-recessed MOSHEMTs are of great potential in millimeter wave frequencies. (cross-disciplinary physics and related areas of science and technology)

  9. Effects of Variability in Fundamental Frequency on L2 Vocabulary Learning: A Comparison between Learners Who Do and Do Not Speak a Tone Language

    Science.gov (United States)

    Barcroft, Joe; Sommers, Mitchell S.

    2014-01-01

    Previous studies (Barcroft & Sommers, 2005; Sommers & Barcroft, 2007) have demonstrated that variability in talker, speaking style, and speaking rate positively affect second language vocabulary learning, whereas variability in overall amplitude and fundamental frequency (F0) do not, at least for native English speakers. Sommers and…

  10. Fundamentals of electro-engineering I

    International Nuclear Information System (INIS)

    Rapsik, M.; Smola, M.; Bohac, M.; Mucha, M.

    2004-01-01

    This is the text-book of the fundamentals of electro-engineering. It contains the following chapters: (1) Selected terms in electro-engineering; (2) Fundamental electric values; (3) Energy and their transformations; (4) Water, hydro-energy and hydro-energetic potential of the Slovak Republic; (5) Nuclear power engineering; (6) Conventional thermal power plants; (7) Heating and cogeneration of electric power and heat production; (8) Equipment of electricity supply system; (9) Measurements in electro-engineering ; (10) Regulation of frequency and voltage, electric power quality

  11. Constraints on pulsar masses from the maximum observed glitch

    Science.gov (United States)

    Pizzochero, P. M.; Antonelli, M.; Haskell, B.; Seveso, S.

    2017-07-01

    Neutron stars are unique cosmic laboratories in which fundamental physics can be probed in extreme conditions not accessible to terrestrial experiments. In particular, the precise timing of rotating magnetized neutron stars (pulsars) reveals sudden jumps in rotational frequency in these otherwise steadily spinning-down objects. These 'glitches' are thought to be due to the presence of a superfluid component in the star, and offer a unique glimpse into the interior physics of neutron stars. In this paper we propose an innovative method to constrain the mass of glitching pulsars, using observations of the maximum glitch observed in a star, together with state-of-the-art microphysical models of the pinning interaction between superfluid vortices and ions in the crust. We study the properties of a physically consistent angular momentum reservoir of pinned vorticity, and we find a general inverse relation between the size of the maximum glitch and the pulsar mass. We are then able to estimate the mass of all the observed glitchers that have displayed at least two large events. Our procedure will allow current and future observations of glitching pulsars to constrain not only the physics of glitch models but also the superfluid properties of dense hadronic matter in neutron star interiors.

  12. Direct maximum parsimony phylogeny reconstruction from genotype data

    OpenAIRE

    Sridhar, Srinath; Lam, Fumei; Blelloch, Guy E; Ravi, R; Schwartz, Russell

    2007-01-01

    Abstract Background Maximum parsimony phylogenetic tree reconstruction from genetic variation data is a fundamental problem in computational genetics with many practical applications in population genetics, whole genome analysis, and the search for genetic predictors of disease. Efficient methods are available for reconstruction of maximum parsimony trees from haplotype data, but such data are difficult to determine directly for autosomal DNA. Data more commonly is available in the form of ge...

  13. Pulse amplitude and frequency effects in a pulsed packed column

    Energy Technology Data Exchange (ETDEWEB)

    Russell, S H

    1954-04-15

    A study has been made of the effect on the efficiency and capacity of applying pulses of varying amplitude and frequency to a packed column. In the efficiency studies, the maximum efficiency was obtained with a pulse having an amplitude of 3/8'' and a frequency of 140 cycles per minute. Under these conditions, the column was about five times as efficient as a simple packed column. Two general types of results were obtained in the capacity studies. Under certain conditions, the capacity increased over that of a simple packed column, but under others, it decreased. Some of the factors causing this were investigated but the fundamental reasons were not determined due to a lack of personnel for the necessary experiments. (author)

  14. Pulse amplitude and frequency effects in a pulsed packed column

    International Nuclear Information System (INIS)

    Russell, S.H.

    1954-04-01

    A study has been made of the effect on the efficiency and capacity of applying pulses of varying amplitude and frequency to a packed column. In the efficiency studies, the maximum efficiency was obtained with a pulse having an amplitude of 3/8'' and a frequency of 140 cycles per minute. Under these conditions, the column was about five times as efficient as a simple packed column. Two general types of results were obtained in the capacity studies. Under certain conditions, the capacity increased over that of a simple packed column, but under others, it decreased. Some of the factors causing this were investigated but the fundamental reasons were not determined due to a lack of personnel for the necessary experiments. (author)

  15. Comparison of fundamental, second harmonic, and superharmonic imaging: a simulation study.

    Science.gov (United States)

    van Neer, Paul L M J; Danilouchkine, Mikhail G; Verweij, Martin D; Demi, Libertario; Voormolen, Marco M; van der Steen, Anton F W; de Jong, Nico

    2011-11-01

    In medical ultrasound, fundamental imaging (FI) uses the reflected echoes from the same spectral band as that of the emitted pulse. The transmission frequency determines the trade-off between penetration depth and spatial resolution. Tissue harmonic imaging (THI) employs the second harmonic of the emitted frequency band to construct images. Recently, superharmonic imaging (SHI) has been introduced, which uses the third to the fifth (super) harmonics. The harmonic level is determined by two competing phenomena: nonlinear propagation and frequency dependent attenuation. Thus, the transmission frequency yielding the optimal trade-off between the spatial resolution and the penetration depth differs for THI and SHI. This paper quantitatively compares the concepts of fundamental, second harmonic, and superharmonic echocardiography at their optimal transmission frequencies. Forward propagation is modeled using a 3D-KZK implementation and the iterative nonlinear contrast source (INCS) method. Backpropagation is assumed to be linear. Results show that the fundamental lateral beamwidth is the narrowest at focus, while the superharmonic one is narrower outside the focus. The lateral superharmonic roll-off exceeds the fundamental and second harmonic roll-off. Also, the axial resolution of SHI exceeds that of FI and THI. The far-field pulse-echo superharmonic pressure is lower than that of the fundamental and second harmonic. SHI appears suited for echocardiography and is expected to improve its image quality at the cost of a slight reduction in depth-of-field.

  16. Effect of current on the maximum possible reward.

    Science.gov (United States)

    Gallistel, C R; Leon, M; Waraczynski, M; Hanau, M S

    1991-12-01

    Using a 2-lever choice paradigm with concurrent variable interval schedules of reward, it was found that when pulse frequency is increased, the preference-determining rewarding effect of 0.5-s trains of brief cathodal pulses delivered to the medial forebrain bundle of the rat saturates (stops increasing) at values ranging from 200 to 631 pulses/s (pps). Raising the current lowered the saturation frequency, which confirms earlier, more extensive findings showing that the rewarding effect of short trains saturates at pulse frequencies that vary from less than 100 pps to more than 800 pps, depending on the current. It was also found that the maximum possible reward--the magnitude of the reward at or beyond the saturation pulse frequency--increases with increasing current. Thus, increasing the current reduces the saturation frequency but increases the subjective magnitude of the maximum possible reward.

  17. Speech task effects on acoustic measure of fundamental frequency in Cantonese-speaking children.

    Science.gov (United States)

    Ma, Estella P-M; Lam, Nina L-N

    2015-12-01

    Speaking fundamental frequency (F0) is a voice measure frequently used to document changes in vocal performance over time. Knowing the intra-subject variability of speaking F0 has implications on its clinical usefulness. The present study examined the speaking F0 elicited from three speech tasks in Cantonese-speaking children. The study also compared the variability of speaking F0 elicited from different speech tasks. Fifty-six vocally healthy Cantonese-speaking children (31 boys and 25 girls) aged between 7.0 and 10.11 years participated. For each child, speaking F0 was elicited using speech tasks at three linguistic levels (sustained vowel /a/ prolongation, reading aloud a sentence and passage). Two types of variability, within-session (trial-to-trial) and across-session (test-retest) variability, were compared across speech tasks. Significant differences in mean speaking F0 values were found between speech tasks. Mean speaking F0 value elicited from sustained vowel phonations was significantly higher than those elicited from the connected speech tasks. The variability of speaking F0 was higher in sustained vowel prolongation than that in connected speech. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Variations in voice level and fundamental frequency with changing background noise level and talker-to-listener distance while wearing hearing protectors: A pilot study

    DEFF Research Database (Denmark)

    Bouserhal, Rachel E.; MacDonald, Ewen; Falk, Tiago H.

    2016-01-01

    in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Study sample: Twelve participants with a mean age of 28 participated in this study. Results: Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded...

  19. Dielectric properties of agricultural products – fundamental principles, influencing factors, and measurement technirques. Chapter 4. Electrotechnologies for Food Processing: Book Series. Volume 3. Radio-Frequency Heating

    Science.gov (United States)

    In this chapter, definitions of dielectric properties, or permittivity, of materials and a brief discussion of the fundamental principles governing their behavior with respect to influencing factors are presented. The basic physics of the influence of frequency of the electric fields and temperatur...

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

    Science.gov (United States)

    Sommers, Mitchell S; Barcroft, Joe

    2006-04-01

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

  1. The role of fundamental frequency and formants in the perception of speaker sex

    Science.gov (United States)

    Hillenbrand, James M.

    2005-09-01

    The purpose of this study was to determine the relative contributions of fundamental frequency (F0) and formants in controlling the speaker-sex percept. A source-filter synthesizer was used to create four versions of 25 sentences spoken by men: (1) unmodified synthesis; (2) F0 only shifted up toward values typical of women; (3) formants only shifted up toward values typical of women; and (4) both F0 and formants shifted up. Identical methods were used to generate four comparable versions of 25 sentences spoken by women (e.g., unmodified synthesis, F0 only shifted down toward values typical of men, etc.). Listening tests showed: (1) perceived talker sex for the unmodified synthesis conditions was nearly always correct; (2) shifting both F0 and formants was usually effective (~82%) in changing the perceived sex of the utterance; (3) shifting either F0 or formants alone was usually ineffective in changing the perceived sex of the utterance. Both F0 and formants are apparently needed to specify speaker sex, though even together these cues are not entirely effective. Results also suggested that F0 is just slightly more important than formants, despite the fact that the male-female difference in F0 is proportionally much larger than the difference in formants. [Work supported by NIH.

  2. Fundamental Limitations for Imaging GEO Satellites

    Science.gov (United States)

    2015-10-18

    Fundamental limitations for imaging GEO satellites D. Mozurkewich Seabrook Engineering , Seabrook, MD 20706 USA H. R. Schmitt, J. T. Armstrong Naval...higher spatial frequency. Send correspondence to David Mozurkewich, Seabrook Engineering , 9310 Dubarry Ave., Seabrook MD 20706 E-mail: dave

  3. Fundamental length

    International Nuclear Information System (INIS)

    Pradhan, T.

    1975-01-01

    The concept of fundamental length was first put forward by Heisenberg from purely dimensional reasons. From a study of the observed masses of the elementary particles known at that time, it is sumrised that this length should be of the order of magnitude 1 approximately 10 -13 cm. It was Heisenberg's belief that introduction of such a fundamental length would eliminate the divergence difficulties from relativistic quantum field theory by cutting off the high energy regions of the 'proper fields'. Since the divergence difficulties arise primarily due to infinite number of degrees of freedom, one simple remedy would be the introduction of a principle that limits these degrees of freedom by removing the effectiveness of the waves with a frequency exceeding a certain limit without destroying the relativistic invariance of the theory. The principle can be stated as follows: It is in principle impossible to invent an experiment of any kind that will permit a distintion between the positions of two particles at rest, the distance between which is below a certain limit. A more elegant way of introducing fundamental length into quantum theory is through commutation relations between two position operators. In quantum field theory such as quantum electrodynamics, it can be introduced through the commutation relation between two interpolating photon fields (vector potentials). (K.B.)

  4. Fundamental investigations of capacitive radio frequency plasmas: simulations and experiments

    International Nuclear Information System (INIS)

    Donkó, Z; Derzsi, A; Hartmann, P; Korolov, I; Schulze, J; Czarnetzki, U; Schüngel, E

    2012-01-01

    Capacitive radio frequency (RF) discharge plasmas have been serving hi-tech industry (e.g. chip and solar cell manufacturing, realization of biocompatible surfaces) for several years. Nonetheless, their complex modes of operation are not fully understood and represent topics of high interest. The understanding of these phenomena is aided by modern diagnostic techniques and computer simulations. From the industrial point of view the control of ion properties is of particular interest; possibilities of independent control of the ion flux and the ion energy have been utilized via excitation of the discharges with multiple frequencies. ‘Classical’ dual-frequency (DF) discharges (where two significantly different driving frequencies are used), as well as discharges driven by a base frequency and its higher harmonic(s) have been analyzed thoroughly. It has been recognized that the second solution results in an electrically induced asymmetry (electrical asymmetry effect), which provides the basis for the control of the mean ion energy. This paper reviews recent advances on studies of the different electron heating mechanisms, on the possibilities of the separate control of ion energy and ion flux in DF discharges, on the effects of secondary electrons, as well as on the non-linear behavior (self-generated resonant current oscillations) of capacitive RF plasmas. The work is based on a synergistic approach of theoretical modeling, experiments and kinetic simulations based on the particle-in-cell approach. (paper)

  5. The impact of rate reduction and increased loudness on fundamental frequency characteristics in dysarthria.

    Science.gov (United States)

    Tjaden, Kris; Wilding, Greg

    2011-01-01

    This study examined the extent to which articulatory rate reduction and increased loudness were associated with adjustments in utterance-level measures of fundamental frequency (F(0)) variability for speakers with dysarthria and healthy controls that have been shown to impact on intelligibility in previously published studies. More generally, the current study sought to compare and contrast how a slower-than-normal rate and increased vocal loudness impact on a variety of utterance-level F(0) characteristics for speakers with dysarthria and healthy controls. Eleven speakers with Parkinson's disease, 15 speakers with multiple sclerosis, and 14 healthy control speakers were audio recorded while reading a passage in habitual, loud, and slow conditions. Magnitude production was used to elicit variations in rate and loudness. Acoustic measures of duration, intensity and F(0) were obtained. For all speaker groups, a slower-than-normal articulatory rate and increased vocal loudness had distinct effects on F(0) relative to the habitual condition, including a tendency for measures of F(0) variation to be greater in the loud condition and reduced in the slow condition. These results suggest implications for the treatment of dysarthria. Copyright © 2010 S. Karger AG, Basel.

  6. 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

  7. Simultaneous negative refraction and focusing of fundamental frequency and second-harmonic fields by two-dimensional photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jun [School of Physics, Beijing Institute of Technology and Beijing Key Laboratory of Fractional Signals and Systems, Beijing 100081 (China); College of Physics and Electronic Engineering, Henan Normal University, 453007 Xinxiang, Henan (China); Zhang, Xiangdong, E-mail: zhangxd@bit.edu.cn [School of Physics, Beijing Institute of Technology and Beijing Key Laboratory of Fractional Signals and Systems, Beijing 100081 (China)

    2015-09-28

    Simultaneous negative refraction for both the fundamental frequency (FF) and second-harmonic (SH) fields in two-dimensional nonlinear photonic crystals have been found through both the physical analysis and exact numerical simulation. By combining such a property with the phase-matching condition and strong second-order susceptibility, we have designed a SH lens to realize focusing for both the FF and SH fields at the same time. Good-quality non-near field images for both FF and SH fields have been observed. The physical mechanism for such SH focusing phenomena has been disclosed, which is different from the backward SH generation as has been pointed out in the previous investigations. In addition, the effect of absorption losses on the phenomena has also been discussed. Thus, potential applications of these phenomena to biphotonic microscopy technique are anticipated.

  8. Measures of maximum magnetic field in 3 GHz radio frequency superconducting cavities; Mesures du gradient accelerateur maximum dans des cavites supraconductrices en regime impulsionnel a 3 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Catherine [Paris-11 Univ., 91 Orsay (France)

    2000-01-19

    Theoretical models have shown that the maximum magnetic field in radio frequency superconducting cavities is the superheating field H{sub sh}. For niobium, H{sub sh} is 25 - 30% higher than the thermodynamical H{sub c} field: H{sub sh} within (240 - 274) mT. However, the maximum magnetic field observed so far is in the range H{sub c,max} = 152 mT for the best 1.3 GHz Nb cavities. This field is lower than the critical field H{sub c1} above which the superconductor breaks up into divided normal and superconducting zones (H{sub c1}{<=}H{sub c}). Thermal instabilities are responsible for this low value. In order to reach H{sub sh} before thermal breakdown, high power short pulses are used. The cavity needs then to be strongly over-coupled. The dedicated test bed has been built from the collaboration between Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Genoa, and the Service d'Etudes et Realisation d'Accelerateurs (SERA) of Laboratoire de l'Accelerateur Lineaire (LAL). The maximum magnetic field, H{sub rf,max}, measurements on INFN cavities give lower results than the theoretical speculations and are in agreement with previous results. The superheating magnetic fields is linked to the magnetic penetration depth. This superconducting characteristic length can be used to determine the quality of niobium through the ratio between the resistivity measured at 300 K and 4.2 K in the normal conducting state (RRR). Results have been compared to previous ones and agree pretty well. They show that the RRR measured on cavities is superficial and lower than the RRR measured on samples which concerns the volume. (author)

  9. Low-frequency noise complaints

    DEFF Research Database (Denmark)

    Pedersen, Christian Sejer; Møller, Henrik; Persson-Waye, Kerstin

    2006-01-01

    is only heard by a single person in the household. This raises the fundamental question whether the complainants are annoyed by an external physical sound, or if other explanations such as low-frequency tinnitus must be sought. The main aim of this study is to answer this fundamental question...

  10. Musicians do not benefit from differences in fundamental frequency when listening to speech in competing speech backgrounds

    DEFF Research Database (Denmark)

    Madsen, Sara Miay Kim; Whiteford, Kelly L.; Oxenham, Andrew J.

    2017-01-01

    Recent studies disagree on whether musicians have an advantage over non-musicians in understanding speech in noise. However, it has been suggested that musicians may be able to use diferences in fundamental frequency (F0) to better understand target speech in the presence of interfering talkers....... Here we studied a relatively large (N=60) cohort of young adults, equally divided between nonmusicians and highly trained musicians, to test whether the musicians were better able to understand speech either in noise or in a two-talker competing speech masker. The target speech and competing speech...... were presented with either their natural F0 contours or on a monotone F0, and the F0 diference between the target and masker was systematically varied. As expected, speech intelligibility improved with increasing F0 diference between the target and the two-talker masker for both natural and monotone...

  11. 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.

  12. Generic maximum likely scale selection

    DEFF Research Database (Denmark)

    Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo

    2007-01-01

    in this work is on applying this selection principle under a Brownian image model. This image model provides a simple scale invariant prior for natural images and we provide illustrative examples of the behavior of our scale estimation on such images. In these illustrative examples, estimation is based......The fundamental problem of local scale selection is addressed by means of a novel principle, which is based on maximum likelihood estimation. The principle is generally applicable to a broad variety of image models and descriptors, and provides a generic scale estimation methodology. The focus...

  13. Evaluation of maximum voided volume in Korean children by use of a 48-h frequency volume chart.

    Science.gov (United States)

    Kim, Sun-Ouck; Kim, Kyung Do; Kim, Young Sig; Kim, Jun Mo; Moon, Du Geon; Park, Sungchan; Lee, Sang Don; Chung, Jae Min; Cho, Won Yeol

    2012-08-01

    Study Type - Diagnostic (validating cohort). Level of Evidence 2a. What's known on the subject? and What does the study add? The relationship between the maximum voided volume followed a linear curve. The formula presented, bladder capacity (mL) = 12 ×[age (years) + 11], is thought to be a reasonable one for Korean children. Korean children have a smaller bladder capacity than that reported in previous Western studies. • To develop practical guidelines for the prediction of normal bladder capacity in Korean children measured by a frequency volume chart (FVC), maximum voided volume (MVV) is an important factor in the diagnosis of children with abnormal voiding function. • In all, 298 children, aged 3-13 years, with no history of voiding disorders volunteered for the study. The MVV was determined in 219 subjects by use of a completely recorded FVC. • Linear regression analysis was used to define the exact relationship between age and bladder capacity. An approximate formula related age to bladder capacity as follows: bladder capacity (mL) = 12 ×[age (years) + 11]. • The relationship between the MVV measured by a FVC by age (3-13 years) of Korean children followed a linear curve. • When applied to normal voiding patterns, the formula presented appears to be a reasonable one for Korean children. © 2011 BJU INTERNATIONAL.

  14. RF discharge slab carbon monoxide laser: overtone lasing (2.5-4.0 micron) and fundamental band tuning (5.0-6.5 micron)

    Science.gov (United States)

    Ionin, Andrey A.; Kozlov, Andrey Yu.; Seleznev, Leonid V.; Sinitsyn, Dmitry V.

    2008-10-01

    Overtone lasing and fundamental band tuning was for the first time obtained in a slab carbon monoxide laser. The compact slab CO laser with active volume 3×30×250 mm3 was excited by a repetitively pulsed capacitive RF discharge (81.36 MHz) with pulse repetition rate 100-500 Hz. The laser electrodes were cooled down to 120 K. Gas mixture CO:Air:He at gas pressures 15-22 Torr was used. An optical scheme "frequency selective master oscillator - laser amplifier" was applied for getting fundamental band tuning. Single line lasing with average power up to several tens of mW was observed on ~100 rotational-vibrational transitions of CO molecule within the spectral range ~5.0 - 6.5 micron. Multiline overtone lasing was observed on ~80 spectral lines within the spectral range ~2.5 -4.0 micron, with maximum single line average output power 12 mW. Total output power of the slab overtone CO laser came up to 0.3 W, with maximum laser efficiency 0.5%. Results of parametric studies of the overtone CO laser including complicated time behavior for laser pulses on different overtone vibrational-rotational transitions are discussed.

  15. Skeletal maturation, fundamental motor skills and motor coordination in children 7-10 years.

    Science.gov (United States)

    Freitas, Duarte L; Lausen, Berthold; Maia, José António; Lefevre, Johan; Gouveia, Élvio Rúbio; Thomis, Martine; Antunes, António Manuel; Claessens, Albrecht L; Beunen, Gaston; Malina, Robert M

    2015-01-01

    Relationships between skeletal maturation and fundamental motor skills and gross motor coordination were evaluated in 429 children (213 boys and 216 girls) 7-10 years. Skeletal age was assessed (Tanner-Whitehouse 2 method), and stature, body mass, motor coordination (Körperkoordinations Test für Kinder, KTK) and fundamental motor skills (Test of Gross Motor Development, TGMD-2) were measured. Relationships among chronological age, skeletal age (expressed as the standardised residual of skeletal age on chronological age) and body size and fundamental motor skills and motor coordination were analysed with hierarchical multiple regression. Standardised residual of skeletal age on chronological age interacting with stature and body mass explained a maximum of 7.0% of the variance in fundamental motor skills and motor coordination over that attributed to body size per se. Standardised residual of skeletal age on chronological age alone accounted for a maximum of 9.0% of variance in fundamental motor skills, and motor coordination over that attributed to body size per se and interactions between standardised residual of skeletal age on chronological age and body size. In conclusion, skeletal age alone or interacting with body size has a negligible influence on fundamental motor skills and motor coordination in children 7-10 years.

  16. Fundamentals of Coherent Synchrotron Radiation in Storage Rings

    International Nuclear Information System (INIS)

    Sannibale, F.; Byrd, J.M.; Loftsdottir, A.; Martin, M.C.; Venturini, M.

    2004-01-01

    We present the fundamental concepts for producing stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The analysis includes distortion of bunch shape from the synchrotron radiation (SR), enhancing higher frequency coherent emission and limits to stable emission due to a microbunching instability excited by the SR. We use these concepts to optimize the performance of a source for CSR emission

  17. Frequency control modelling - basics

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul Ejnar; Zeni, Lorenzo

    2016-01-01

    The purpose of this report is to provide an introduction on how the system balance in an island system can be maintained by controlling the frequency. The power balance differential equation, which is fundamental in understanding the effect on the system frequency of the unbalance between...

  18. Towards a frequency-dependent discrete maximum principle for the implicit Monte Carlo equations

    Energy Technology Data Exchange (ETDEWEB)

    Wollaber, Allan B [Los Alamos National Laboratory; Larsen, Edward W [Los Alamos National Laboratory; Densmore, Jeffery D [Los Alamos National Laboratory

    2010-12-15

    It has long been known that temperature solutions of the Implicit Monte Carlo (IMC) equations can exceed the external boundary temperatures, a so-called violation of the 'maximum principle.' Previous attempts at prescribing a maximum value of the time-step size {Delta}{sub t} that is sufficient to eliminate these violations have recommended a {Delta}{sub t} that is typically too small to be used in practice and that appeared to be much too conservative when compared to numerical solutions of the IMC equations for practical problems. In this paper, we derive a new estimator for the maximum time-step size that includes the spatial-grid size {Delta}{sub x}. This explicitly demonstrates that the effect of coarsening {Delta}{sub x} is to reduce the limitation on {Delta}{sub t}, which helps explain the overly conservative nature of the earlier, grid-independent results. We demonstrate that our new time-step restriction is a much more accurate means of predicting violations of the maximum principle. We discuss how the implications of the new, grid-dependent timestep restriction can impact IMC solution algorithms.

  19. Towards a frequency-dependent discrete maximum principle for the implicit Monte Carlo equations

    International Nuclear Information System (INIS)

    Wollaber, Allan B.; Larsen, Edward W.; Densmore, Jeffery D.

    2011-01-01

    It has long been known that temperature solutions of the Implicit Monte Carlo (IMC) equations can exceed the external boundary temperatures, a so-called violation of the 'maximum principle'. Previous attempts at prescribing a maximum value of the time-step size Δ t that is sufficient to eliminate these violations have recommended a Δ t that is typically too small to be used in practice and that appeared to be much too conservative when compared to numerical solutions of the IMC equations for practical problems. In this paper, we derive a new estimator for the maximum time-step size that includes the spatial-grid size Δ x . This explicitly demonstrates that the effect of coarsening Δ x is to reduce the limitation on Δ t , which helps explain the overly conservative nature of the earlier, grid-independent results. We demonstrate that our new time-step restriction is a much more accurate means of predicting violations of the maximum principle. We discuss how the implications of the new, grid-dependent time-step restriction can impact IMC solution algorithms. (author)

  20. The Supercontinuum Laser Source Fundamentals with Updated References

    CERN Document Server

    Alfano, Robert R

    2006-01-01

    Photonics and nonlinear optics are important areas of science, engineering and technology. One of the most important ultrafast nonlinear optical processes is the supercontinuum (SC) – the production of intense white light pulses covering: uv, visible, NIR, MIR, and IR. It is produced using ultrashort laser pulses (ps/fs) to produce the ultrabroad band of frequencies. This book covers the fundamental principles and surveys research of current thinkers and experts in the field with updated references of the key breakthroughs over the past decade and a half. The application of SC are time-resolved pump-SC probe absorption and excitation spectroscopy for chemistry, biology and physics fundamental processes; optical coherence tomography; ultrashort pulse generation in femtosecond and attosecond regions; frequency clocks; phase stabilization; optical communication; atmospheric science; lightning control; optical medical imaging; biological cell imaging; and metrology standards.

  1. CAMAC programmable-control frequency synthesizer

    International Nuclear Information System (INIS)

    Yumaguzin, T.Kh.; Vyazovkin, D.E.; Nazirov, Eh.P.; Tuktarov, R.F.

    1989-01-01

    Synthesizer allows to set frequency with 0.015% accuracy and to scan it with variable step. Frequency controlled divider with further summing-up of divided frequency with fundamental one is used in synthesizer, and it has allowed to use digit of the input code and to obtain 3-4 MHz frequency range. Variation of operation flowsheet in the other frequency range is possible. K-155 and K-531 series microcircuits were used during development

  2. Fundamentals of electromagnetics 2 quasistatics and waves

    CERN Document Server

    Voltmer, David

    2007-01-01

    This book is the second of two volumes which have been created to provide an understanding of the basic principles and applications of electromagnetic fields for electrical engineering students. Fundamentals of Electromagnetics Vol 2: Quasistatics and Waves examines how the low-frequency models of lumped elements are modified to include parasitic elements. For even higher frequencies, wave behavior in space and on transmission lines is explained. Finally, the textbook concludes with details of transmission line properties and applications. Upon completion of this book and its companion Fundame

  3. Fundamental limits to frequency estimation: a comprehensive microscopic perspective

    Science.gov (United States)

    Haase, J. F.; Smirne, A.; Kołodyński, J.; Demkowicz-Dobrzański, R.; Huelga, S. F.

    2018-05-01

    We consider a metrology scenario in which qubit-like probes are used to sense an external field that affects their energy splitting in a linear fashion. Following the frequency estimation approach in which one optimizes the state and sensing time of the probes to maximize the sensitivity, we provide a systematic study of the attainable precision under the impact of noise originating from independent bosonic baths. Specifically, we invoke an explicit microscopic derivation of the probe dynamics using the spin-boson model with weak coupling of arbitrary geometry. We clarify how the secular approximation leads to a phase-covariant (PC) dynamics, where the noise terms commute with the field Hamiltonian, while the inclusion of non-secular contributions breaks the PC. Moreover, unless one restricts to a particular (i.e., Ohmic) spectral density of the bath modes, the noise terms may contain relevant information about the frequency to be estimated. Thus, by considering general evolutions of a single probe, we study regimes in which these two effects have a non-negligible impact on the achievable precision. We then consider baths of Ohmic spectral density yet fully accounting for the lack of PC, in order to characterize the ultimate attainable scaling of precision when N probes are used in parallel. Crucially, we show that beyond the semigroup (Lindbladian) regime the Zeno limit imposing the 1/N 3/2 scaling of the mean squared error, recently derived assuming PC, generalises to any dynamics of the probes, unless the latter are coupled to the baths in the direction perfectly transversal to the frequency encoding—when a novel scaling of 1/N 7/4 arises. As our microscopic approach covers all classes of dissipative dynamics, from semigroup to non-Markovian ones (each of them potentially non-phase-covariant), it provides an exhaustive picture, in which all the different asymptotic scalings of precision naturally emerge.

  4. Maximum Efficiency per Torque Control of Permanent-Magnet Synchronous Machines

    Directory of Open Access Journals (Sweden)

    Qingbo Guo

    2016-12-01

    Full Text Available High-efficiency permanent-magnet synchronous machine (PMSM drive systems need not only optimally designed motors but also efficiency-oriented control strategies. However, the existing control strategies only focus on partial loss optimization. This paper proposes a novel analytic loss model of PMSM in either sine-wave pulse-width modulation (SPWM or space vector pulse width modulation (SVPWM which can take into account both the fundamental loss and harmonic loss. The fundamental loss is divided into fundamental copper loss and fundamental iron loss which is estimated by the average flux density in the stator tooth and yoke. In addition, the harmonic loss is obtained from the Bertotti iron loss formula by the harmonic voltages of the three-phase inverter in either SPWM or SVPWM which are calculated by double Fourier integral analysis. Based on the analytic loss model, this paper proposes a maximum efficiency per torque (MEPT control strategy which can minimize the electromagnetic loss of PMSM in the whole operation range. As the loss model of PMSM is too complicated to obtain the analytical solution of optimal loss, a golden section method is applied to achieve the optimal operation point accurately, which can make PMSM work at maximum efficiency. The optimized results between SPWM and SVPWM show that the MEPT in SVPWM has a better effect on the optimization performance. Both the theory analysis and experiment results show that the MEPT control can significantly improve the efficiency performance of the PMSM in each operation condition with a satisfied dynamic performance.

  5. Fundamentals of semiconductor devices

    CERN Document Server

    Lindmayer, Joseph

    1965-01-01

    Semiconductor properties ; semiconductor junctions or diodes ; transistor fundamentals ; inhomogeneous impurity distributions, drift or graded-base transistors ; high-frequency properties of transistors ; band structure of semiconductors ; high current densities and mechanisms of carrier transport ; transistor transient response and recombination processes ; surfaces, field-effect transistors, and composite junctions ; additional semiconductor characteristics ; additional semiconductor devices and microcircuits ; more metal, insulator, and semiconductor combinations for devices ; four-pole parameters and configuration rotation ; four-poles of combined networks and devices ; equivalent circuits ; the error function and its properties ; Fermi-Dirac statistics ; useful physical constants.

  6. Experimental measurements of competition between fundamental and second harmonic emission in a quasi-optical gyrotron

    International Nuclear Information System (INIS)

    Alberti, S.; Pedrozzi, M.; Tran, M.Q.; Hogge, J.P.; Tran, T.M.; Muggli, P.; Joedicke, B.; Mathews, H.G.

    1990-04-01

    A quasi-optical gyrotron (QOG) designed for operation at the fundamental (Ω ce ≅100 GHz) exhibits simultaneous emission at Ω ce and 2Ω ce (second harmonic). For a beam current of 4 A, 20% of the total RF power is emitted at the second harmonic. The experimental measurements show that the excitation of the second harmonic is only possible when the fundamental is present. The frequency of the second harmonic is locked by the frequency of the fundamental. Experimental evidence shows that when the second harmonic is not excited, total efficiency is enhanced. (author) 6 refs., 5 figs., 1 tab

  7. Broadband pulsed difference frequency generation laser source centered 3326 nm based on ring fiber lasers

    Science.gov (United States)

    Chen, Guangwei; Li, Wenlei

    2018-03-01

    A broadband pulsed mid-infrared difference frequency generation (DFG) laser source based on MgO-doped congruent LiNbO3 bulk is experimentally demonstrated, which employs a homemade pulsed ytterbium-doped ring fiber laser and a continuous wave erbium-doped ring fiber laser to act as seed sources. The experimental results indicate that the perfect phase match crystal temperature is about 74.5∘C. The maximum spectrum bandwidth of idler is about 60 nm with suitable polarization states of fundamental lights. The central wavelength of idlers varies from 3293 nm to 3333 nm over the crystal temperature ranges of 70.4-76∘C. A jump of central wavelength exists around crystal temperature of 72∘C with variation of about 30 nm. The conversion efficiency of DFG can be tuned with the crystal temperature and polarization states of fundamental lights.

  8. Fundamental limits of radio interferometers: calibration and source parameter estimation

    OpenAIRE

    Trott, Cathryn M.; Wayth, Randall B.; Tingay, Steven J.

    2012-01-01

    We use information theory to derive fundamental limits on the capacity to calibrate next-generation radio interferometers, and measure parameters of point sources for instrument calibration, point source subtraction, and data deconvolution. We demonstrate the implications of these fundamental limits, with particular reference to estimation of the 21cm Epoch of Reionization power spectrum with next-generation low-frequency instruments (e.g., the Murchison Widefield Array -- MWA, Precision Arra...

  9. A daily oscillation in the fundamental frequency and amplitude of harmonic syllables of zebra finch song.

    Directory of Open Access Journals (Sweden)

    William E Wood

    Full Text Available Complex motor skills are more difficult to perform at certain points in the day (for example, shortly after waking, but the daily trajectory of motor-skill error is more difficult to predict. By undertaking a quantitative analysis of the fundamental frequency (FF and amplitude of hundreds of zebra finch syllables per animal per day, we find that zebra finch song follows a previously undescribed daily oscillation. The FF and amplitude of harmonic syllables rises across the morning, reaching a peak near mid-day, and then falls again in the late afternoon until sleep. This oscillation, although somewhat variable, is consistent across days and across animals and does not require serotonin, as animals with serotonergic lesions maintained daily oscillations. We hypothesize that this oscillation is driven by underlying physiological factors which could be shared with other taxa. Song production in zebra finches is a model system for studying complex learned behavior because of the ease of gathering comprehensive behavioral data and the tractability of the underlying neural circuitry. The daily oscillation that we describe promises to reveal new insights into how time of day affects the ability to accomplish a variety of complex learned motor skills.

  10. Maximum nondiffracting propagation distance of aperture-truncated Airy beams

    Science.gov (United States)

    Chu, Xingchun; Zhao, Shanghong; Fang, Yingwu

    2018-05-01

    Airy beams have called attention of many researchers due to their non-diffracting, self-healing and transverse accelerating properties. A key issue in research of Airy beams and its applications is how to evaluate their nondiffracting propagation distance. In this paper, the critical transverse extent of physically realizable Airy beams is analyzed under the local spatial frequency methodology. The maximum nondiffracting propagation distance of aperture-truncated Airy beams is formulated and analyzed based on their local spatial frequency. The validity of the formula is verified by comparing the maximum nondiffracting propagation distance of an aperture-truncated ideal Airy beam, aperture-truncated exponentially decaying Airy beam and exponentially decaying Airy beam. Results show that the formula can be used to evaluate accurately the maximum nondiffracting propagation distance of an aperture-truncated ideal Airy beam. Therefore, it can guide us to select appropriate parameters to generate Airy beams with long nondiffracting propagation distance that have potential application in the fields of laser weapons or optical communications.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-19

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  13. Effect of a Nitrogen Impurity on the Fundamental Raman Band of Diamond Single Crystals

    Science.gov (United States)

    Gusakov, G. A.; Samtsov, M. P.; Voropay, E. S.

    2018-05-01

    The effect of nitrogen defects in natural and synthetic diamond single crystals on the position and half-width of the fundamental Raman band was investigated. Samples containing the main types of nitrogen lattice defects at impurity contents of 1-1500 ppm were studied. The parameters of the Stokes and anti-Stokes components in Raman spectra of crystals situated in a cell with distilled water to minimize the influence of heating by the exciting laser radiation were analyzed to determine the effect of a nitrogen impurity in the diamond crystal lattice. It was shown that an increase of impurity atoms in the crystals in the studied concentration range resulted in broadening of the Raman band from 1.61 to 2.85 cm-1 and shifting of the maximum to lower frequency from 1332.65 to 1332.3 cm-1. The observed effect was directly proportional to the impurity concentration and depended on the form of the impurity incorporated into the diamond lattice. It was found that the changes in the position and half-width of the fundamental Raman band for diamond were consistent with the magnitude of crystal lattice distortions due to the presence of impurity defects and obeyed the Gruneisen law.

  14. Maximum power operation of interacting molecular motors

    DEFF Research Database (Denmark)

    Golubeva, Natalia; Imparato, Alberto

    2013-01-01

    , as compared to the non-interacting system, in a wide range of biologically compatible scenarios. We furthermore consider the case where the motor-motor interaction directly affects the internal chemical cycle and investigate the effect on the system dynamics and thermodynamics.......We study the mechanical and thermodynamic properties of different traffic models for kinesin which are relevant in biological and experimental contexts. We find that motor-motor interactions play a fundamental role by enhancing the thermodynamic efficiency at maximum power of the motors...

  15. Dual-wavelength green laser with a 4.5 THz frequency difference based on self-frequency- doubling in Nd3+ -doped aperiodically poled lithium niobate.

    Science.gov (United States)

    Maestre, H; Torregrosa, A J; Fernández-Pousa, C R; Rico, M L; Capmany, J

    2008-05-01

    We report a dual-wavelength continuous-wave laser at 542.4 and 546.8 nm based on an Nd(3+)-doped aperiodically poled lithium niobate crystal. Two fundamental infrared (IR) wavelengths at 1084.8 and 1093.6 nm are simultaneously oscillated and self-frequency-doubled to green. The aperiodic domain distribution patterned in the crystal allows for quasi-phase matched self-frequency-doubling of both IR fundamentals while avoiding their sum-frequency mixing.

  16. Investigation of power and frequency for 3D conformal MRI-controlled transurethral ultrasound therapy with a dual frequency multi-element transducer.

    Science.gov (United States)

    N'djin, William Apoutou; Burtnyk, Mathieu; Bronskill, Michael; Chopra, Rajiv

    2012-01-01

    Transurethral ultrasound therapy uses real-time magnetic resonance (MR) temperature feedback to enable the 3D control of thermal therapy accurately in a region within the prostate. Previous canine studies showed the feasibility of this method in vivo. The aim of this study was to reduce the procedure time, while maintaining targeting accuracy, by investigating new combinations of treatment parameters. Simulations and validation experiments in gel phantoms were used, with a collection of nine 3D realistic target prostate boundaries obtained from previous preclinical studies, where multi-slice MR images were acquired with the transurethral device in place. Acoustic power and rotation rate were varied based on temperature feedback at the prostate boundary. Maximum acoustic power and rotation rate were optimised interdependently, as a function of prostate radius and transducer operating frequency. The concept of dual frequency transducers was studied, using the fundamental frequency or the third harmonic component depending on the prostate radius. Numerical modelling enabled assessment of the effects of several acoustic parameters on treatment outcomes. The range of treatable prostate radii extended with increasing power, and tended to narrow with decreasing frequency. Reducing the frequency from 8 MHz to 4 MHz or increasing the surface acoustic power from 10 to 20 W/cm(2) led to treatment times shorter by up to 50% under appropriate conditions. A dual frequency configuration of 4/12 MHz with 20 W/cm(2) ultrasound intensity exposure can treat entire prostates up to 40 cm(3) in volume within 30 min. The interdependence between power and frequency may, however, require integrating multi-parametric functions in the controller for future optimisations.

  17. Ionic screening effect on low-frequency drain current fluctuations in liquid-gated nanowire FETs

    International Nuclear Information System (INIS)

    Lu, Ming-Pei; Vire, Eric; Montès, Laurent

    2015-01-01

    The ionic screening effect plays an important role in determining the fundamental surface properties within liquid–semiconductor interfaces. In this study, we investigated the characteristics of low-frequency drain current noise in liquid-gated nanowire (NW) field effect transistors (FETs) to obtain physical insight into the effect of ionic screening on low-frequency current fluctuation. When the NW FET was operated close to the gate voltage corresponding to the maximum transconductance, the magnitude of the low-frequency noise for the NW exposed to a low-ionic-strength buffer (0.001 M) was approximately 70% greater than that when exposed to a high-ionic-strength buffer (0.1 M). We propose a noise model, considering the charge coupling efficiency associated with the screening competition between the electrolyte buffer and the NW, to describe the ionic screening effect on the low-frequency drain current noise in liquid-gated NW FET systems. This report not only provides a physical understanding of the ionic screening effect behind the low-frequency current noise in liquid-gated FETs but also offers useful information for developing the technology of NW FETs with liquid-gated architectures for application in bioelectronics, nanosensors, and hybrid nanoelectronics. (paper)

  18. RF and microwave engineering fundamentals of wireless communications

    CERN Document Server

    Gustrau, Frank

    2012-01-01

    This book provides a fundamental and practical introduction to radio frequency and microwave engineering and physical aspects of wireless communication In this book, the author addresses a wide range of radio-frequency and microwave topics with emphasis on physical aspects including EM and voltage waves, transmission lines, passive circuits, antennas, radio wave propagation. Up-to-date RF design tools like RF circuit simulation, EM simulation and computerized smith charts, are used in various examples to demonstrate how these methods can be applied effectively in RF engineering

  19. An increased rectal maximum tolerable volume and long anal canal are associated with poor short-term response to biofeedback therapy for patients with anismus with decreased bowel frequency and normal colonic transit time.

    Science.gov (United States)

    Rhee, P L; Choi, M S; Kim, Y H; Son, H J; Kim, J J; Koh, K C; Paik, S W; Rhee, J C; Choi, K W

    2000-10-01

    Biofeedback is an effective therapy for a majority of patients with anismus. However, a significant proportion of patients still failed to respond to biofeedback, and little has been known about the factors that predict response to biofeedback. We evaluated the factors associated with poor response to biofeedback. Biofeedback therapy was offered to 45 patients with anismus with decreased bowel frequency (less than three times per week) and normal colonic transit time. Any differences in demographics, symptoms, and parameters of anorectal physiologic tests were sought between responders (in whom bowel frequency increased up to three times or more per week after biofeedback) and nonresponders (in whom bowel frequency remained less than three times per week). Thirty-one patients (68.9 percent) responded to biofeedback and 14 patients (31.1 percent) did not. Anal canal length was longer in nonresponders than in responders (4.53 +/- 0.5 vs. 4.08 +/- 0.56 cm; P = 0.02), and rectal maximum tolerable volume was larger in nonresponders than in responders. (361 +/- 87 vs. 302 +/- 69 ml; P = 0.02). Anal canal length and rectal maximum tolerable volume showed significant differences between responders and nonresponders on multivariate analysis (P = 0.027 and P = 0.034, respectively). This study showed that a long anal canal and increased rectal maximum tolerable volume are associated with poor short-term response to biofeedback for patients with anismus with decreased bowel frequency and normal colonic transit time.

  20. Remarks on the maximum luminosity

    Science.gov (United States)

    Cardoso, Vitor; Ikeda, Taishi; Moore, Christopher J.; Yoo, Chul-Moon

    2018-04-01

    The quest for fundamental limitations on physical processes is old and venerable. Here, we investigate the maximum possible power, or luminosity, that any event can produce. We show, via full nonlinear simulations of Einstein's equations, that there exist initial conditions which give rise to arbitrarily large luminosities. However, the requirement that there is no past horizon in the spacetime seems to limit the luminosity to below the Planck value, LP=c5/G . Numerical relativity simulations of critical collapse yield the largest luminosities observed to date, ≈ 0.2 LP . We also present an analytic solution to the Einstein equations which seems to give an unboundedly large luminosity; this will guide future numerical efforts to investigate super-Planckian luminosities.

  1. A fundamental residue pitch perception bias for tone language speakers

    Science.gov (United States)

    Petitti, Elizabeth

    A complex tone composed of only higher-order harmonics typically elicits a pitch percept equivalent to the tone's missing fundamental frequency (f0). When judging the direction of residue pitch change between two such tones, however, listeners may have completely opposite perceptual experiences depending on whether they are biased to perceive changes based on the overall spectrum or the missing f0 (harmonic spacing). Individual differences in residue pitch change judgments are reliable and have been associated with musical experience and functional neuroanatomy. Tone languages put greater pitch processing demands on their speakers than non-tone languages, and we investigated whether these lifelong differences in linguistic pitch processing affect listeners' bias for residue pitch. We asked native tone language speakers and native English speakers to perform a pitch judgment task for two tones with missing fundamental frequencies. Given tone pairs with ambiguous pitch changes, listeners were asked to judge the direction of pitch change, where the direction of their response indicated whether they attended to the overall spectrum (exhibiting a spectral bias) or the missing f0 (exhibiting a fundamental bias). We found that tone language speakers are significantly more likely to perceive pitch changes based on the missing f0 than English speakers. These results suggest that tone-language speakers' privileged experience with linguistic pitch fundamentally tunes their basic auditory processing.

  2. Speed Estimation in Geared Wind Turbines Using the Maximum Correlation Coefficient

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Marhadi, Kun S.; Jensen, Bogi Bech

    2015-01-01

    to overcome the above mentioned issues. The high speed stage shaft angular velocity is calculated based on the maximum correlation coefficient between the 1 st gear mesh frequency of the last gearbox stage and a pure sinus tone of known frequency and phase. The proposed algorithm utilizes vibration signals...

  3. effects of flexural rigidity of reinforcement bars on the fundamental ...

    African Journals Online (AJOL)

    NIJOTECH

    Nigerian Journal of Technology, Vol. 28, No. 2, September, 2009 ... forth between the concrete surface and the ... number of layers on the fundamental frequency of vibration ... isotropic and an orthotropic flat plate models for predicting simple ...

  4. Relationship of physical activity to fundamental movement skills among adolescents.

    Science.gov (United States)

    Okely, A D; Booth, M L; Patterson, J W

    2001-11-01

    To determine the relationship of participation in organized and nonorganized physical activity with fundamental movement skills among adolescents. Male and female children in Grade 8 (mean age, 13.3 yr) and Grade 10 (mean age, 15.3 yr) were assessed on six fundamental movement skills (run, vertical jump, catch, overhand throw, forehand strike, and kick). Physical activity was assessed using a self-report recall measure where students reported the type, duration, and frequency of participation in organized physical activity and nonorganized physical activity during a usual week. Multiple regression analysis indicated that fundamental movement skills significantly predicted time in organized physical activity, although the percentage of variance it could explain was small. This prediction was stronger for girls than for boys. Multiple regression analysis showed no relationship between time in nonorganized physical activity and fundamental movement skills. Fundamental movement skills are significantly associated with adolescents' participation in organized physical activity, but predict only a small portion of it.

  5. Longitudinal study of the fundamental frequency of hunger cries along the first 6 months of healthy babies.

    Science.gov (United States)

    Baeck, Heidi Elisabeth; de Souza, Marcio Nogueira

    2007-09-01

    Potentially rich in information, the baby's cry has motivated several researches along the years. Although most of these studies have generated important knowledge about the baby's cry, they were focused on the neonatal period. The few longitudinal studies on changes in the acoustical features of the cry over the baby's growth have been done with a small sample and a large recording interval. Aiming to overcome such methodological limitations, this work investigated hunger cries using a more representative sample size (30 babies) and time resolution (biweekly intervals) from birth to 6 months of baby's age. The findings indicate that the fundamental frequency (f0) of the cry signals did vary more than previously reported in the literature. The results showed a widespread oscillatory behavior in f0 evolution along all the 6 months with an especially significant decrease from birth to the 15th day of life. The present results are not clinically applicable yet, but they pointed some novel aspects of the f0 mean values along the baby's growth. These findings and further longitudinal studies can help standardize age-related cry parameters, which are essential for medical and language development researches.

  6. Picosecond-precision multichannel autonomous time and frequency counter

    Science.gov (United States)

    Szplet, R.; Kwiatkowski, P.; RóŻyc, K.; Jachna, Z.; Sondej, T.

    2017-12-01

    This paper presents the design, implementation, and test results of a multichannel time interval and frequency counter developed as a desktop instrument. The counter contains four main functional modules for (1) performing precise measurements, (2) controlling and fast data processing, (3) low-noise power suppling, and (4) supplying a stable reference clock (optional rubidium standard). A fundamental for the counter, the time interval measurement is based on time stamping combined with a period counting and in-period two-stage time interpolation that allows us to achieve wide measurement range (above 1 h), high precision (even better than 4.5 ps), and high measurement speed (up to 91.2 × 106 timestamps/s). The frequency is measured up to 3.0 GHz with the use of the reciprocal method. Wide functionality of the counter includes also the evaluation of frequency stability of clocks and oscillators (Allan deviation) and phase variation (time interval error, maximum time interval error, time deviation). The 8-channel measurement module is based on a field programmable gate array device, while the control unit involves a microcontroller with a high performance ARM-Cortex core. An efficient and user-friendly control of the counter is provided either locally, through the built-in keypad or/and color touch panel, or remotely, with the aid of USB, Ethernet, RS232C, or RS485 interfaces.

  7. What if the Diatoms of the Deep Chlorophyll Maximum Can Ascend?

    Science.gov (United States)

    Villareal, T. A.

    2016-02-01

    Buoyancy regulation is an integral part of diatom ecology via its role in sinking rates and is fundamental to understanding their distribution and abundance. Numerous studies have documented the effects of size and nutrition on sinking rates. Many pelagic diatoms have low intrinsic sinking rates when healthy and nutrient-replete (deep chlorophyll maximum. The potential for ascending behavior adds an additional layer of complexity by allowing both active depth regulation similar to that observed in flagellated taxa and upward transport by some fraction of deep euphotic zone diatom blooms supported by nutrient injection. In this talk, I review the data documenting positive buoyancy in small diatoms, offer direct visual evidence of ascending behavior in common diatoms typical of both oceanic and coastal zones, and note the characteristics of sinking rate distributions within a single species. Buoyancy control leads to bidirectional movement at similar rates across a wide size spectrum of diatoms although the frequency of ascending behavior may be only a small portion of the individual species' abundance. While much remains to be learned, the paradigm of unidirectional downward movement by diatoms is both inaccurate and an oversimplification.

  8. Maximum Likelihood Estimation and Inference With Examples in R, SAS and ADMB

    CERN Document Server

    Millar, Russell B

    2011-01-01

    This book takes a fresh look at the popular and well-established method of maximum likelihood for statistical estimation and inference. It begins with an intuitive introduction to the concepts and background of likelihood, and moves through to the latest developments in maximum likelihood methodology, including general latent variable models and new material for the practical implementation of integrated likelihood using the free ADMB software. Fundamental issues of statistical inference are also examined, with a presentation of some of the philosophical debates underlying the choice of statis

  9. Dynamics of Microbeams under Multi-Frequency Excitations

    KAUST Repository

    Ibrahim, Alwathiqbellah

    2017-01-24

    This paper presents an investigation of the dynamics of microbeams under multiple harmonic electrostatic excitation frequencies. First, the response of a cantilever microbeam to two alternating current (AC) source excitation is examined. We show by simulations the response of the microbeam at primary resonance (near the fundamental natural frequency) and at secondary resonances (near half, superharmonic, and twice, subharmonic, the fundamental natural frequency). A multimode Galerkin method combined with the Euler-Bernoulli beam equation, accounting for the nonlinear electrostatic force, has been used to develop a reduced order model. The response of the cantilever microbeam to three AC source excitation is also investigated and shown as a promising technique to enhance the bandwidth of resonators. Finally, an experimental study of a clamped-clamped microbeam is conducted, demonstrating the multi-frequency excitation resonances using two, three, and four AC sources.

  10. Dynamics of Microbeams under Multi-Frequency Excitations

    KAUST Repository

    Ibrahim, Alwathiqbellah; Jaber, Nizar; Chandran, Akhil; Thirupathi, Maloth; Younis, Mohammad I.

    2017-01-01

    This paper presents an investigation of the dynamics of microbeams under multiple harmonic electrostatic excitation frequencies. First, the response of a cantilever microbeam to two alternating current (AC) source excitation is examined. We show by simulations the response of the microbeam at primary resonance (near the fundamental natural frequency) and at secondary resonances (near half, superharmonic, and twice, subharmonic, the fundamental natural frequency). A multimode Galerkin method combined with the Euler-Bernoulli beam equation, accounting for the nonlinear electrostatic force, has been used to develop a reduced order model. The response of the cantilever microbeam to three AC source excitation is also investigated and shown as a promising technique to enhance the bandwidth of resonators. Finally, an experimental study of a clamped-clamped microbeam is conducted, demonstrating the multi-frequency excitation resonances using two, three, and four AC sources.

  11. Estimating the maximum potential revenue for grid connected electricity storage :

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Raymond Harry; Silva Monroy, Cesar Augusto.

    2012-12-01

    The valuation of an electricity storage device is based on the expected future cash flow generated by the device. Two potential sources of income for an electricity storage system are energy arbitrage and participation in the frequency regulation market. Energy arbitrage refers to purchasing (stor- ing) energy when electricity prices are low, and selling (discharging) energy when electricity prices are high. Frequency regulation is an ancillary service geared towards maintaining system frequency, and is typically procured by the independent system operator in some type of market. This paper outlines the calculations required to estimate the maximum potential revenue from participating in these two activities. First, a mathematical model is presented for the state of charge as a function of the storage device parameters and the quantities of electricity purchased/sold as well as the quantities o ered into the regulation market. Using this mathematical model, we present a linear programming optimization approach to calculating the maximum potential revenue from an elec- tricity storage device. The calculation of the maximum potential revenue is critical in developing an upper bound on the value of storage, as a benchmark for evaluating potential trading strate- gies, and a tool for capital nance risk assessment. Then, we use historical California Independent System Operator (CAISO) data from 2010-2011 to evaluate the maximum potential revenue from the Tehachapi wind energy storage project, an American Recovery and Reinvestment Act of 2009 (ARRA) energy storage demonstration project. We investigate the maximum potential revenue from two di erent scenarios: arbitrage only and arbitrage combined with the regulation market. Our analysis shows that participation in the regulation market produces four times the revenue compared to arbitrage in the CAISO market using 2010 and 2011 data. Then we evaluate several trading strategies to illustrate how they compare to the

  12. Peculiarities of frequency dependence of type 3 solar radio bursts duration

    International Nuclear Information System (INIS)

    Tsybko, Ya.G.

    1989-01-01

    From the averaged data of type 3 bursts at the fixed frequencies in the range 12.5-25 MHz and out of this limit it is concluded that there exist two branges of the burst duration dependence on the frequency. This splitting allows to distinguish bursts occurring at the fundamental and the second harmonics of the plasma frequency decreasing with height in the solar corona. The type 3b radiation is characterized by a separate diagram of the mean duration versus frequency of the stria-bursts at the fundamental harmonic

  13. Experimental measurements on a 100 GHz frequency tunable quasioptical gyrotron

    International Nuclear Information System (INIS)

    Alberti, S.; Tran, M.Q.; Hogge, J.P.; Tran, T.M.; Bondeson, A.; Muggli, P.; Perrenoud, A.; Joedicke, B.; Mathews, H.G.

    1990-01-01

    Experiments on a 100 GHz quasioptical (QO) gyrotron operating at the fundamental (ω=Ω ce ) are described. Powers larger than 90 kW at an efficiency of about 12% were achieved. Depending on the electron beam parameters, the frequency spectrum of the output can be either single moded or multimoded. One of the main advantages of the QO gyrotron over the conventional gyrotron is its continuous frequency tunability. Various techniques to tune the output frequency have been tested, such as changing the mirror separation, the beam voltage, or the main magnetic field. Within the limitations of the present setup, 5% tunability was achieved. The QO gyrotron designed for operation at the fundamental frequency exhibits simultaneous emission at 100 GHz (fundamental) and 200 GHz (second harmonic). For a beam current of 4 A, 20% of the total rf power is emitted at the second harmonic

  14. Fundamental Frequency Variation of Neonatal Spontaneous Crying Predicts Language Acquisition in Preterm and Term Infants.

    Science.gov (United States)

    Shinya, Yuta; Kawai, Masahiko; Niwa, Fusako; Imafuku, Masahiro; Myowa, Masako

    2017-01-01

    Spontaneous cries of infants exhibit rich melodic features (i.e., time variation of fundamental frequency [ F 0 ]) even during the neonatal period, and the development of these characteristics might provide an essential base for later expressive prosody in language. However, little is known about the melodic features of spontaneous cries in preterm infants, who have a higher risk of later language-related problems. Thus, the present study investigated how preterm birth influenced melodic features of spontaneous crying at term-equivalent age as well as how these melodic features related to language outcomes at 18 months of corrected age in preterm and term infants. At term, moderate-to-late preterm (MLP) infants showed spontaneous cries with significantly higher F 0 variation and melody complexity than term infants, while there were no significant differences between very preterm (VP) and term infants. Furthermore, larger F 0 variation within cry series at term was significantly related to better language and cognitive outcomes, particularly expressive language skills, at 18 months. On the other hand, no other melodic features at term predicted any developmental outcomes at 18 months. The present results suggest that the additional postnatal vocal experience of MLP preterm infants increased F 0 variation and the complexity of spontaneous cries at term. Additionally, the increases in F 0 variation may partly reflect the development of voluntary vocal control, which, in turn, contributes to expressive language in infancy.

  15. Influence of modulation frequency in rubidium cell frequency standards

    Science.gov (United States)

    Audoin, C.; Viennet, J.; Cyr, N.; Vanier, J.

    1983-01-01

    The error signal which is used to control the frequency of the quartz crystal oscillator of a passive rubidium cell frequency standard is considered. The value of the slope of this signal, for an interrogation frequency close to the atomic transition frequency is calculated and measured for various phase (or frequency) modulation waveforms, and for several values of the modulation frequency. A theoretical analysis is made using a model which applies to a system in which the optical pumping rate, the relaxation rates and the RF field are homogeneous. Results are given for sine-wave phase modulation, square-wave frequency modulation and square-wave phase modulation. The influence of the modulation frequency on the slope of the error signal is specified. It is shown that the modulation frequency can be chosen as large as twice the non-saturated full-width at half-maximum without a drastic loss of the sensitivity to an offset of the interrogation frequency from center line, provided that the power saturation factor and the amplitude of modulation are properly adjusted.

  16. Fundamental ecology is fundamental.

    Science.gov (United States)

    Courchamp, Franck; Dunne, Jennifer A; Le Maho, Yvon; May, Robert M; Thébaud, Christophe; Hochberg, Michael E

    2015-01-01

    The primary reasons for conducting fundamental research are satisfying curiosity, acquiring knowledge, and achieving understanding. Here we develop why we believe it is essential to promote basic ecological research, despite increased impetus for ecologists to conduct and present their research in the light of potential applications. This includes the understanding of our environment, for intellectual, economical, social, and political reasons, and as a major source of innovation. We contend that we should focus less on short-term, objective-driven research and more on creativity and exploratory analyses, quantitatively estimate the benefits of fundamental research for society, and better explain the nature and importance of fundamental ecology to students, politicians, decision makers, and the general public. Our perspective and underlying arguments should also apply to evolutionary biology and to many of the other biological and physical sciences. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Sub-Doppler Frequency Metrology in HD for Tests of Fundamental Physics.

    Science.gov (United States)

    Cozijn, F M J; Dupré, P; Salumbides, E J; Eikema, K S E; Ubachs, W

    2018-04-13

    Weak transitions in the (2,0) overtone band of the hydrogen deuteride molecule at λ=1.38  μm were measured in saturated absorption using the technique of noise-immune cavity-enhanced optical heterodyne molecular spectroscopy. Narrow Doppler-free lines were interrogated with a spectroscopy laser locked to a frequency comb laser referenced to an atomic clock to yield transition frequencies [R(1)=217105181895(20)  kHz; R(2)=219042856621(28)  kHz; R(3)=220704304951(28)  kHz] at three orders of magnitude improved accuracy. These benchmark values provide a test of QED in the smallest neutral molecule, and they open up an avenue to resolve the proton radius puzzle, as well as constrain putative fifth forces and extra dimensions.

  18. Fundamental radiation effects studies in the fusion materials program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1982-01-01

    Fundamental radiation effects studies in the US Fusion Materials Program generally fall under the aegis of the Damage Analysis and Fundamental Studies (DAFS) Program. In a narrow sense, the problem addressed by the DAFS program is the prediction of radiation effects in fusion devices using data obtained in non-representative environments. From the onset, the program has had near-term and long-term components. The premise for the latter is that there will be large economic penalties for uncertainties in predictive capability. Fusion devices are expected to be large and complex and unanticipated maintenance will be costly. It is important that predictions are based on a maximum of understanding and a minimum of empiricism. Gaining this understanding is the thrust of the long-term component. (orig.)

  19. Amplitude and frequency modulation control of sound production in a mechanical model of the avian syrinx

    DEFF Research Database (Denmark)

    Elemans, Coen; Muller, Mees; Larsen, Ole Næsbye

    2009-01-01

    membrane and generate a wide variety of ‘syllables' with simple sweeps of the control parameters. We show that the membrane exhibits high frequency, self-sustained oscillations in the audio range (>600 Hz fundamental frequency) using laser Doppler vibrometry, and systematically explore the conditions...... for sound production of the model in its control space. The fundamental frequency of the sound increases with tension in three membranes with different stiffness and mass. The lowerbound fundamental frequency increases with membrane mass. The membrane vibrations are strongly coupled to the resonance...

  20. Maximum power flux of auroral kilometric radiation

    International Nuclear Information System (INIS)

    Benson, R.F.; Fainberg, J.

    1991-01-01

    The maximum auroral kilometric radiation (AKR) power flux observed by distant satellites has been increased by more than a factor of 10 from previously reported values. This increase has been achieved by a new data selection criterion and a new analysis of antenna spin modulated signals received by the radio astronomy instrument on ISEE 3. The method relies on selecting AKR events containing signals in the highest-frequency channel (1980, kHz), followed by a careful analysis that effectively increased the instrumental dynamic range by more than 20 dB by making use of the spacecraft antenna gain diagram during a spacecraft rotation. This analysis has allowed the separation of real signals from those created in the receiver by overloading. Many signals having the appearance of AKR harmonic signals were shown to be of spurious origin. During one event, however, real second harmonic AKR signals were detected even though the spacecraft was at a great distance (17 R E ) from Earth. During another event, when the spacecraft was at the orbital distance of the Moon and on the morning side of Earth, the power flux of fundamental AKR was greater than 3 x 10 -13 W m -2 Hz -1 at 360 kHz normalized to a radial distance r of 25 R E assuming the power falls off as r -2 . A comparison of these intense signal levels with the most intense source region values (obtained by ISIS 1 and Viking) suggests that multiple sources were observed by ISEE 3

  1. Using variable DC sources in order to improve the voltage quality of a multilevel STATCOM with low frequency modulation

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Najjar, Mohammad; Blaabjerg, Frede

    2016-01-01

    In this paper, a Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) method, which utilizes adjustable dc links, is presented for a Static Synchronous Compensator (STATCOM) based on Cascaded H-Bridge (CHB) multilevel converter. The proposed switching algorithm is able to fix the capac......In this paper, a Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) method, which utilizes adjustable dc links, is presented for a Static Synchronous Compensator (STATCOM) based on Cascaded H-Bridge (CHB) multilevel converter. The proposed switching algorithm is able to fix...... unequal dc link voltages more levels at the output is achievable compared to the symmetrical multilevel converters that could be used in enhancing the power quality, while keeping the switching frequency near the fundamental (the maximum switching frequency can be kept below 150 Hz). The validity...

  2. Fundamental of cryogenics (for superconducting RF technology)

    CERN Document Server

    Pierini, Paolo

    2013-01-01

    This review briefly illustrates a few fundamental concepts of cryogenic engineering, the technological practice that allows reaching and maintaining the low-temperature operating conditions of the superconducting devices needed in particle accelerators. To limit the scope of the task, and not to duplicate coverage of cryogenic engineering concepts particularly relevant to superconducting magnets that can be found in previous CAS editions, the overview presented in this course focuses on superconducting radio-frequency cavities.

  3. On Frequency Combs in Monolithic Resonators

    Science.gov (United States)

    Savchenkov, A. A.; Matsko, A. B.; Maleki, L.

    2016-06-01

    Optical frequency combs have become indispensable in astronomical measurements, biological fingerprinting, optical metrology, and radio frequency photonic signal generation. Recently demonstrated microring resonator-based Kerr frequency combs point the way towards chip scale optical frequency comb generator retaining major properties of the lab scale devices. This technique is promising for integrated miniature radiofrequency and microwave sources, atomic clocks, optical references and femtosecond pulse generators. Here we present Kerr frequency comb development in a historical perspective emphasizing its similarities and differences with other physical phenomena. We elucidate fundamental principles and describe practical implementations of Kerr comb oscillators, highlighting associated solved and unsolved problems.

  4. Maximum power gains of radio-frequency-driven two-energy-component tokamak reactors

    International Nuclear Information System (INIS)

    Jassby, D.L.

    1974-11-01

    Two-energy-component fusion reactors in which the suprathermal component (D) is produced by harmonic cyclotron ''runaway'' of resonant ions are considered. In one ideal case, the fast hydromagnetic wave at ω = 2ω/sub cD/ produces an energy distribution f(W) approximately constant (up to W/sub max/) that includes all deuterons, which then thermalize and react with the cold tritons. In another ideal case, f(W) approximately constant is maintained by the fast wave at ω = ω/sub cD/. If one neglects (1) direct rf input to the bulk-plasma electrons and tritons, and (2) the fact that many deuterons are not resonantly accelerated, then the maximum ideal power gain is about 0.85 Q/sub m/ in the first case and 1.05 Q/sub m/ in the second case, where Q/sub m/ is the maximum fusion gain in the beam-injection scheme (e.g., Q/sub m/ = 1.9 at T/sub e/ = 10 keV). Because of nonideal effects, the cyclotron runaway phenomenon may find its most practical use in the heating of 50:50 D--T plasmas to ignition. (auth)

  5. On Maximum Entropy and Inference

    Directory of Open Access Journals (Sweden)

    Luigi Gresele

    2017-11-01

    Full Text Available Maximum entropy is a powerful concept that entails a sharp separation between relevant and irrelevant variables. It is typically invoked in inference, once an assumption is made on what the relevant variables are, in order to estimate a model from data, that affords predictions on all other (dependent variables. Conversely, maximum entropy can be invoked to retrieve the relevant variables (sufficient statistics directly from the data, once a model is identified by Bayesian model selection. We explore this approach in the case of spin models with interactions of arbitrary order, and we discuss how relevant interactions can be inferred. In this perspective, the dimensionality of the inference problem is not set by the number of parameters in the model, but by the frequency distribution of the data. We illustrate the method showing its ability to recover the correct model in a few prototype cases and discuss its application on a real dataset.

  6. Measurements of intermediate-frequency electric and magnetic fields in households

    Energy Technology Data Exchange (ETDEWEB)

    Aerts, Sam, E-mail: sam.aerts@intec.ugent.be [Department of Information Technology, Ghent University/iMinds, iGent, Technologiepark-Zwijnaarde 15, B-9052 Ghent (Belgium); Calderon, Carolina [Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom); Valič, Blaž [Institute of Non-Ionizing Radiation (INIS), Pohorskega bataljona 215, Ljubljana 1000 (Slovenia); Maslanyj, Myron; Addison, Darren; Mee, Terry; Goiceanu, Cristian [Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom); Verloock, Leen; Van den Bossche, Matthias [Department of Information Technology, Ghent University/iMinds, iGent, Technologiepark-Zwijnaarde 15, B-9052 Ghent (Belgium); Gajšek, Peter [Institute of Non-Ionizing Radiation (INIS), Pohorskega bataljona 215, Ljubljana 1000 (Slovenia); Vermeulen, Roel [Institute for Risk Assessment Sciences, Department of Environmental Epidemiology, Utrecht University, Yalelaan 2, 3508 Utrecht (Netherlands); Röösli, Martin [Swiss Tropical and Public Health Institute (Swiss TPH), Socinstrasse 57, P.O. Box, 4002 Basel (Switzerland); University of Basel, Petersplatz 1, 4003 Basel (Switzerland); Cardis, Elisabeth [Barcelona Institute for Global Health (ISGlobal) and Municipal Institute of Medical Research (IMIM-Hospital del Mar), Doctor Aiguader, 88, 08003 Barcelona (Spain); Martens, Luc; Joseph, Wout [Department of Information Technology, Ghent University/iMinds, iGent, Technologiepark-Zwijnaarde 15, B-9052 Ghent (Belgium)

    2017-04-15

    Historically, assessment of human exposure to electric and magnetic fields has focused on the extremely-low-frequency (ELF) and radiofrequency (RF) ranges. However, research on the typically emitted fields in the intermediate-frequency (IF) range (300 Hz to 1 MHz) as well as potential effects of IF fields on the human body remains limited, although the range of household appliances with electrical components working in the IF range has grown significantly (e.g., induction cookers and compact fluorescent lighting). In this study, an extensive measurement survey was performed on the levels of electric and magnetic fields in the IF range typically present in residences as well as emitted by a wide range of household appliances under real-life circumstances. Using spot measurements, residential IF field levels were found to be generally low, while the use of certain appliances at close distance (20 cm) may result in a relatively high exposure. Overall, appliance emissions contained either harmonic signals, with fundamental frequencies between 6 kHz and 300 kHz, which were sometimes accompanied by regions in the IF spectrum of rather noisy, elevated field strengths, or much more capricious spectra, dominated by 50 Hz harmonics emanating far in the IF domain. The maximum peak field strengths recorded at 20 cm were 41.5 V/m and 2.7 A/m, both from induction cookers. Finally, none of the appliance emissions in the IF range exceeded the exposure summation rules recommended by the International Commission on Non-Ionizing Radiation Protection guidelines and the International Electrotechnical Commission (IEC 62233) standard at 20 cm and beyond (maximum exposure quotients EQ{sub E} 1.0 and {sub E}Q{sub H} 0.13). - Highlights: • Survey of residential electric and magnetic fields at intermediate frequencies (IF). • IF-EF and -MF emitted by 280 household appliances were characterised. • Strongest emitters were induction cookers, CFLs, LCD-TVs, and microwave ovens. • No

  7. Measurements of intermediate-frequency electric and magnetic fields in households

    International Nuclear Information System (INIS)

    Aerts, Sam; Calderon, Carolina; Valič, Blaž; Maslanyj, Myron; Addison, Darren; Mee, Terry; Goiceanu, Cristian; Verloock, Leen; Van den Bossche, Matthias; Gajšek, Peter; Vermeulen, Roel; Röösli, Martin; Cardis, Elisabeth; Martens, Luc; Joseph, Wout

    2017-01-01

    Historically, assessment of human exposure to electric and magnetic fields has focused on the extremely-low-frequency (ELF) and radiofrequency (RF) ranges. However, research on the typically emitted fields in the intermediate-frequency (IF) range (300 Hz to 1 MHz) as well as potential effects of IF fields on the human body remains limited, although the range of household appliances with electrical components working in the IF range has grown significantly (e.g., induction cookers and compact fluorescent lighting). In this study, an extensive measurement survey was performed on the levels of electric and magnetic fields in the IF range typically present in residences as well as emitted by a wide range of household appliances under real-life circumstances. Using spot measurements, residential IF field levels were found to be generally low, while the use of certain appliances at close distance (20 cm) may result in a relatively high exposure. Overall, appliance emissions contained either harmonic signals, with fundamental frequencies between 6 kHz and 300 kHz, which were sometimes accompanied by regions in the IF spectrum of rather noisy, elevated field strengths, or much more capricious spectra, dominated by 50 Hz harmonics emanating far in the IF domain. The maximum peak field strengths recorded at 20 cm were 41.5 V/m and 2.7 A/m, both from induction cookers. Finally, none of the appliance emissions in the IF range exceeded the exposure summation rules recommended by the International Commission on Non-Ionizing Radiation Protection guidelines and the International Electrotechnical Commission (IEC 62233) standard at 20 cm and beyond (maximum exposure quotients EQ E 1.0 and E Q H 0.13). - Highlights: • Survey of residential electric and magnetic fields at intermediate frequencies (IF). • IF-EF and -MF emitted by 280 household appliances were characterised. • Strongest emitters were induction cookers, CFLs, LCD-TVs, and microwave ovens. • No emissions exceeded

  8. Experience with a second language affects the use of fundamental frequency in speech segmentation

    Science.gov (United States)

    Broersma, Mirjam; Cho, Taehong; Kim, Sahyang; Martínez-García, Maria Teresa; Connell, Katrina

    2017-01-01

    This study investigates whether listeners’ experience with a second language learned later in life affects their use of fundamental frequency (F0) as a cue to word boundaries in the segmentation of an artificial language (AL), particularly when the cues to word boundaries conflict between the first language (L1) and second language (L2). F0 signals phrase-final (and thus word-final) boundaries in French but word-initial boundaries in English. Participants were functionally monolingual French listeners, functionally monolingual English listeners, bilingual L1-English L2-French listeners, and bilingual L1-French L2-English listeners. They completed the AL-segmentation task with F0 signaling word-final boundaries or without prosodic cues to word boundaries (monolingual groups only). After listening to the AL, participants completed a forced-choice word-identification task in which the foils were either non-words or part-words. The results show that the monolingual French listeners, but not the monolingual English listeners, performed better in the presence of F0 cues than in the absence of such cues. Moreover, bilingual status modulated listeners’ use of F0 cues to word-final boundaries, with bilingual French listeners performing less accurately than monolingual French listeners on both word types but with bilingual English listeners performing more accurately than monolingual English listeners on non-words. These findings not only confirm that speech segmentation is modulated by the L1, but also newly demonstrate that listeners’ experience with the L2 (French or English) affects their use of F0 cues in speech segmentation. This suggests that listeners’ use of prosodic cues to word boundaries is adaptive and non-selective, and can change as a function of language experience. PMID:28738093

  9. GHz band frequency hopping PLL-based frequency synthesizers

    Institute of Scientific and Technical Information of China (English)

    XU Yong; WANG Zhi-gong; GUAN Yu; XU Zhi-jun; QIAO Lu-feng

    2005-01-01

    In this paper we describe a full-integrated circuit containing all building blocks of a completed PLL-based synthesizer except for low pass filter(LPF).The frequency synthesizer is designed for a frequency hopping (FH) transceiver operating up to 1.5 GHz as a local oscillator. The architecture of Voltage Controlled Oscillator (VCO) is optimized to get better performance, and a phase noise of -111.85-dBc/Hz @ 1 MHz and a tuning range of 250 MHz are gained at a centre frequency of 1.35 GHz.A novel Dual-Modulus Prescaler(DMP) is designed to achieve a very low jitter and a lower power.The settling time of PLL is 80 μs while the reference frequency is 400 KHz.This monolithic frequency synthesizer is to integrate all main building blocks of PLL except for the low pass filter,with a maximum VCO output frequency of 1.5 GHz,and is fabricated with a 0.18 μm mixed signal CMOS process. Low power dissipation, low phase noise, large tuning range and fast settling time are gained in this design.

  10. Nonlinear generation of the fundamental radiation in plasmas

    International Nuclear Information System (INIS)

    Chian, A.C.L.; Rizzato, F.B.

    1993-01-01

    Nonlinear generation of coherent electromagnetic radiation by intense Langmuir waves in the vicinity of the fundamental plasma frequency f p is of current interest in space and laboratory plasmas. In a pioneer work, Lashmore-Davies demonstrated that an efficient process for converting intense Langmuir waves into f p electromagnetic radiation can be achieved by two counterstreaming Langmuir pump waves through an electromagnetic oscillating two-stream instability. Recently Chian and Alves, Akimoto and Rizzato and Chian extended the formalism of Lashmore-Davies in order to include mixed processes with induced modes which are purely electrostatic or electromagnetic. In this paper we extend our previous analysis, in order to study the nonlinear interaction involving travelling electromagnetic pumps, low-frequency density fluctuations and high-frequency f p modes which can be electrostatic-electromagnetic hybrids. (author) 5 refs., 2 figs

  11. Narrow band interference cancelation in OFDM: Astructured maximum likelihood approach

    KAUST Repository

    Sohail, Muhammad Sadiq; Al-Naffouri, Tareq Y.; Al-Ghadhban, Samir N.

    2012-01-01

    This paper presents a maximum likelihood (ML) approach to mitigate the effect of narrow band interference (NBI) in a zero padded orthogonal frequency division multiplexing (ZP-OFDM) system. The NBI is assumed to be time variant and asynchronous

  12. Maximum Available Accuracy of FM-CW Radars

    Directory of Open Access Journals (Sweden)

    V. Ricny

    2009-12-01

    Full Text Available This article deals with the principles and above all with the maximum available measuring accuracy analyse of FM-CW (Frequency Modulated Continuous Wave radars, which are usually employed for distance and velocity measurements of moving objects in road traffic, as well as air traffic and in other applications. These radars often form an important part of the active safety equipment of high-end cars – the so-called anticollision systems. They usually work in the frequency bands of mm waves (24, 35, 77 GHz. Function principles and analyses of factors, that dominantly influence the distance measurement accuracy of these equipments especially in the modulation and demodulation part, are shown in the paper.

  13. Achieving Optimal Quantum Acceleration of Frequency Estimation Using Adaptive Coherent Control.

    Science.gov (United States)

    Naghiloo, M; Jordan, A N; Murch, K W

    2017-11-03

    Precision measurements of frequency are critical to accurate time keeping and are fundamentally limited by quantum measurement uncertainties. While for time-independent quantum Hamiltonians the uncertainty of any parameter scales at best as 1/T, where T is the duration of the experiment, recent theoretical works have predicted that explicitly time-dependent Hamiltonians can yield a 1/T^{2} scaling of the uncertainty for an oscillation frequency. This quantum acceleration in precision requires coherent control, which is generally adaptive. We experimentally realize this quantum improvement in frequency sensitivity with superconducting circuits, using a single transmon qubit. With optimal control pulses, the theoretically ideal frequency precision scaling is reached for times shorter than the decoherence time. This result demonstrates a fundamental quantum advantage for frequency estimation.

  14. Fundamental (f) oscillations in a magnetically coupled solar interior-atmosphere system - An analytical approach

    Science.gov (United States)

    Pintér, Balázs; Erdélyi, R.

    2018-01-01

    Solar fundamental (f) acoustic mode oscillations are investigated analytically in a magnetohydrodynamic (MHD) model. The model consists of three layers in planar geometry, representing the solar interior, the magnetic atmosphere, and a transitional layer sandwiched between them. Since we focus on the fundamental mode here, we assume the plasma is incompressible. A horizontal, canopy-like, magnetic field is introduced to the atmosphere, in which degenerated slow MHD waves can exist. The global (f-mode) oscillations can couple to local atmospheric Alfvén waves, resulting, e.g., in a frequency shift of the oscillations. The dispersion relation of the global oscillation mode is derived, and is solved analytically for the thin-transitional layer approximation and for the weak-field approximation. Analytical formulae are also provided for the frequency shifts due to the presence of a thin transitional layer and a weak atmospheric magnetic field. The analytical results generally indicate that, compared to the fundamental value (ω =√{ gk }), the mode frequency is reduced by the presence of an atmosphere by a few per cent. A thin transitional layer reduces the eigen-frequencies further by about an additional hundred microhertz. Finally, a weak atmospheric magnetic field can slightly, by a few percent, increase the frequency of the eigen-mode. Stronger magnetic fields, however, can increase the f-mode frequency by even up to ten per cent, which cannot be seen in observed data. The presence of a magnetic atmosphere in the three-layer model also introduces non-permitted propagation windows in the frequency spectrum; here, f-mode oscillations cannot exist with certain values of the harmonic degree. The eigen-frequencies can be sensitive to the background physical parameters, such as an atmospheric density scale-height or the rate of the plasma density drop at the photosphere. Such information, if ever observed with high-resolution instrumentation and inverted, could help to

  15. A mechanism for frequency modulation in songbirds shared with humans.

    Science.gov (United States)

    Amador, Ana; Margoliash, Daniel

    2013-07-03

    In most animals that vocalize, control of fundamental frequency is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental frequency during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study frequency modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure variations over a limited interval during production of a syllable concomitantly affected the frequency of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed frequency modulations induced by pressure variations. We conclude that the observed interaction between pressure and frequency was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental frequencies of vocalizations. Thus, although there are separate brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and frequency. We hypothesize that the control of pressure and frequency is combined holistically at higher levels of the vocalization pathways.

  16. 4th International Conference on Trapped Charged Particles and Fundamental Physics

    CERN Document Server

    Comyn, M; Thomson, J; Gwinner, G; TCP'06; TCP 2006

    2007-01-01

    The TCP06 conference in Parksville on Vancouver Island showcased the impressive progress in the study of fundamental physics using trapped charged particles. Atom and ion trapping has revolutionized atomic physics and related fields. It has proven to be particularly useful for fundamental physics experiments, as the tight control over the particles' degrees of freedom leads to increased precision and efficient use of exotic species such as radioactive atoms or anti-matter. The topics of the meeting included fundamental interactions and symmetries, quantum electrodynamics, quantum state manipulation and quantum information, precision spectroscopy and frequency standards, storage ring physics, highly charged ions in traps, traps for radioactive isotopes, plasmas and collective behaviour, and anti-hydrogen. Highlights from related fields such as fundamental physics studies with neutral, trapped atoms were also presented. The combination of overview articles by leaders in the field and detailed reports on recent ...

  17. On Frequency Combs in Monolithic Resonators

    Directory of Open Access Journals (Sweden)

    Savchenkov A. A.

    2016-06-01

    Full Text Available Optical frequency combs have become indispensable in astronomical measurements, biological fingerprinting, optical metrology, and radio frequency photonic signal generation. Recently demonstrated microring resonator-based Kerr frequency combs point the way towards chip scale optical frequency comb generator retaining major properties of the lab scale devices. This technique is promising for integrated miniature radiofrequency and microwave sources, atomic clocks, optical references and femtosecond pulse generators. Here we present Kerr frequency comb development in a historical perspective emphasizing its similarities and differences with other physical phenomena. We elucidate fundamental principles and describe practical implementations of Kerr comb oscillators, highlighting associated solved and unsolved problems.

  18. Jarzynski equality in the context of maximum path entropy

    Science.gov (United States)

    González, Diego; Davis, Sergio

    2017-06-01

    In the global framework of finding an axiomatic derivation of nonequilibrium Statistical Mechanics from fundamental principles, such as the maximum path entropy - also known as Maximum Caliber principle -, this work proposes an alternative derivation of the well-known Jarzynski equality, a nonequilibrium identity of great importance today due to its applications to irreversible processes: biological systems (protein folding), mechanical systems, among others. This equality relates the free energy differences between two equilibrium thermodynamic states with the work performed when going between those states, through an average over a path ensemble. In this work the analysis of Jarzynski's equality will be performed using the formalism of inference over path space. This derivation highlights the wide generality of Jarzynski's original result, which could even be used in non-thermodynamical settings such as social systems, financial and ecological systems.

  19. 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.

  20. Mode-field half-widths of Gaussian approximation for the fundamental mode of two kinds of optical waveguides

    International Nuclear Information System (INIS)

    Lian-Huang, Li; Fu-Yuan, Guo

    2009-01-01

    This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field. Then, it presents a new method where the mode-field half-width of Gaussian approximation for the fundamental mode should be defined according to the maximal matching efficiency method. The relationship between the mode-field half-width of the Gaussian approximate field obtained from the maximal matching efficiency and normalized frequency is studied; furthermore, two formulas of mode-field half-widths as a function of normalized frequency are proposed

  1. Development of a spectral analyzer for radio-frequencies; Etude et realisation d'un analyseur de spectres pour radio-frequences

    Energy Technology Data Exchange (ETDEWEB)

    Bourbigot, J [Commission a l' Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-04-01

    This report describes an apparatus designed to show on the screen of a cathode ray tube the amplitude and frequency distribution of the spectral components of a given signal. The frequency range is from 5 kHz to 25 MHz. Two fundamental elements are used in the development of this apparatus, a ferrite and a ring modulator. The basic properties of these elements are studied and discussed. A theoretical study for the determination of the fundamental parameters of the analyzer is presented in the Appendix. (author) [French] On decrit un appareil qui permet de representer sur l'ecran d'un tube a rayons cathodiques la distribution en frequence et en amplitude des composantes spectrales d'un signal donne. Il fonctionne dans la gamme de frequences s'etendant de 5 kHz a 25 MHz. Deux elements interviennent fondamentalement dans la realisation de cet appareil: un echantillon de ferrite et un modulateur en anneau. Des proprietes particulieres de ces elements sont etudiees et discutees. En annexe une theorie s'appliquant a la determination de parametres fondamentaux de l'analyseur est developpee. (auteur)

  2. Narrow band interference cancelation in OFDM: Astructured maximum likelihood approach

    KAUST Repository

    Sohail, Muhammad Sadiq

    2012-06-01

    This paper presents a maximum likelihood (ML) approach to mitigate the effect of narrow band interference (NBI) in a zero padded orthogonal frequency division multiplexing (ZP-OFDM) system. The NBI is assumed to be time variant and asynchronous with the frequency grid of the ZP-OFDM system. The proposed structure based technique uses the fact that the NBI signal is sparse as compared to the ZP-OFDM signal in the frequency domain. The structure is also useful in reducing the computational complexity of the proposed method. The paper also presents a data aided approach for improved NBI estimation. The suitability of the proposed method is demonstrated through simulations. © 2012 IEEE.

  3. Experimental Determination of Operating and Maximum Power Transfer Efficiencies at Resonant Frequency in a Wireless Power Transfer System using PP Network Topology with Top Coupling

    Science.gov (United States)

    Ramachandran, Hema; Pillai, K. P. P.; Bindu, G. R.

    2017-08-01

    A two-port network model for a wireless power transfer system taking into account the distributed capacitances using PP network topology with top coupling is developed in this work. The operating and maximum power transfer efficiencies are determined analytically in terms of S-parameters. The system performance predicted by the model is verified with an experiment consisting of a high power home light load of 230 V, 100 W and is tested for two forced resonant frequencies namely, 600 kHz and 1.2 MHz. The experimental results are in close agreement with the proposed model.

  4. Low Frequency Space Array

    International Nuclear Information System (INIS)

    Dennison, B.; Weiler, K.W.; Johnston, K.J.

    1987-01-01

    The Low Frequency Space Array (LFSA) is a conceptual mission to survey the entire sky and to image individual sources at frequencies between 1.5 and 26 MHz, a frequency range over which the earth's ionosphere transmits poorly or not at all. With high resolution, high sensitivity observations, a new window will be opened in the electromagnetic spectrum for astronomical investigation. Also, extending observations down to such low frequencies will bring astronomy to the fundamental limit below which the galaxy becomes optically thick due to free-free absorption. A number of major scientific goals can be pursued with such a mission, including mapping galactic emission and absorption, studies of individual source spectra in a frequency range where a number of important processes may play a role, high resolution imaging of extended sources, localization of the impulsive emission from Jupiter, and a search for coherent emission processes. 19 references

  5. Fundamental understanding of the Di-Air system (an alternative NO

    NARCIS (Netherlands)

    Wang, Y.; Makkee, M.

    2018-01-01

    Toyota's Di-Air DeNOx system is a promising DeNOx system to meet NOx emission requirement during the real driving, yet, a fundamental understanding largely lacks, e.g. the benefit of fast frequency fuel injection. Ceria is the main ingredient in Di-Air catalyst

  6. Nanoelectromechanical systems: Nanodevice motion at microwave frequencies

    Science.gov (United States)

    Henry Huang, Xue Ming; Zorman, Christian A.; Mehregany, Mehran; Roukes, Michael L.

    2003-01-01

    It has been almost forgotten that the first computers envisaged by Charles Babbage in the early 1800s were mechanical and not electronic, but the development of high-frequency nanoelectromechanical systems is now promising a range of new applications, including sensitive mechanical charge detectors and mechanical devices for high-frequency signal processing, biological imaging and quantum measurement. Here we describe the construction of nanodevices that will operate with fundamental frequencies in the previously inaccessible microwave range (greater than 1 gigahertz). This achievement represents a significant advance in the quest for extremely high-frequency nanoelectromechanical systems.

  7. String Stretching, Frequency Modulation, and Banjo Clang

    OpenAIRE

    Politzer, David

    2014-01-01

    The banjo’s floating bridge, string break angle, and flexible drumhead all contribute to substantial audio range frequency modulation. From the world of electronic music synthesis, it is known that modulating higher frequency sounds with lower acoustic frequencies leads to metallic and bell-like tone. The mechanics of the banjo does just that quite naturally, modulating fundamentals and harmonics with the motion of the bridge. In technical terms, with a floating bridge, string stretching is f...

  8. Fundamental damper power calculation of the 56 MHz SRF cavity for RHIC

    International Nuclear Information System (INIS)

    Wu, Q.; Bellavia, S.; Ben-Zvi, I.; Grau, M.; Miglionico, G.; Pai, C.

    2011-01-01

    At each injection period during RHIC's operation, the beam's frequency sweeps across a wide range, and some of its harmonics will cross the frequency of the 56MHz SRF cavity. To avoid excitation of the cavity at these times, we designed a fundamental damper for the quarter-wave resonator to damp the cavity heavily. The power extracted by the fundamental damper should correspond to the power handling ability of the system at all stages. In this paper, we discuss the power output from the fundamental damper when it is fully extracted, inserted, and any intermediate point. A Fundamental Damper (FD) will greatly reduce the cavity's Q factor to ∼300 during the acceleration phase of the beam. However, when the beam is at store and the FD is removed, the cavity is excited by both the yellow and the blue beams at 2 x 0.3A to attain the required 2MV voltage across its gap. The cavity then is operated to increase the luminosity of the RHIC experiments. Table 1 lists the parameters of the FD. Figure 1 shows the configuration of the FD fully inserted into the 56MHz SRF cavity; this complete insertion is defined as the start location (0cm) of FD simulation, an assumption we make throughout this paper. The power consumed by the cavity while maintaining the beam's energy and its orbit is compensated by the 28MHz accelerating cavities in the storage ring. The power dissipation of the external load is dynamic with respect to the position of the FD during its extraction. As a function of the external Q and the EM field in the cavity, the power should peak with the FD at a certain vertical location. Our calculation of the power extracted is detailed in the following sections. Figure 2 plots the frequency change in the cavity, and the external Q against the changes in position of the FD. The location of the FD is selected carefully such that the frequency will approach the designed working point from the lower side only. The loaded Q of the cavity is 223 when the FD is fully

  9. 303 nm continuous wave ultraviolet laser generated by intracavity frequency-doubling of diode-pumped Pr3+:LiYF4 laser

    Science.gov (United States)

    Zhu, Pengfei; Zhang, Chaomin; Zhu, Kun; Ping, Yunxia; Song, Pei; Sun, Xiaohui; Wang, Fuxin; Yao, Yi

    2018-03-01

    We demonstrate an efficient and compact ultraviolet laser at 303 nm generated by intracavity frequency doubling of a continuous wave (CW) laser diode-pumped Pr3+:YLiF4 laser at 607 nm. A cesium lithium borate (CLBO) crystal, cut for critical type I phase matching at room temperature, is used for second-harmonic generation (SHG) of the fundamental laser. By using an InGaN laser diode array emitting at 444.3 nm with a maximum incident power of 10 W, as high as 68 mW of CW output power at 303 nm is achieved. The output power stability in 4 h is better than 2.85%. To the best of our knowledge, this is high efficient UV laser generated by frequency doubling of an InGaN laser diode array pumped Pr3+:YLiF4 laser.

  10. A clock network for geodesy and fundamental science.

    Science.gov (United States)

    Lisdat, C; Grosche, G; Quintin, N; Shi, C; Raupach, S M F; Grebing, C; Nicolodi, D; Stefani, F; Al-Masoudi, A; Dörscher, S; Häfner, S; Robyr, J-L; Chiodo, N; Bilicki, S; Bookjans, E; Koczwara, A; Koke, S; Kuhl, A; Wiotte, F; Meynadier, F; Camisard, E; Abgrall, M; Lours, M; Legero, T; Schnatz, H; Sterr, U; Denker, H; Chardonnet, C; Le Coq, Y; Santarelli, G; Amy-Klein, A; Le Targat, R; Lodewyck, J; Lopez, O; Pottie, P-E

    2016-08-09

    Leveraging the unrivalled performance of optical clocks as key tools for geo-science, for astronomy and for fundamental physics beyond the standard model requires comparing the frequency of distant optical clocks faithfully. Here, we report on the comparison and agreement of two strontium optical clocks at an uncertainty of 5 × 10(-17) via a newly established phase-coherent frequency link connecting Paris and Braunschweig using 1,415 km of telecom fibre. The remote comparison is limited only by the instability and uncertainty of the strontium lattice clocks themselves, with negligible contributions from the optical frequency transfer. A fractional precision of 3 × 10(-17) is reached after only 1,000 s averaging time, which is already 10 times better and more than four orders of magnitude faster than any previous long-distance clock comparison. The capability of performing high resolution international clock comparisons paves the way for a redefinition of the unit of time and an all-optical dissemination of the SI-second.

  11. Multiscale energy reallocation during low-frequency steady-state brain response.

    Science.gov (United States)

    Wang, Yifeng; Chen, Wang; Ye, Liangkai; Biswal, Bharat B; Yang, Xuezhi; Zou, Qijun; Yang, Pu; Yang, Qi; Wang, Xinqi; Cui, Qian; Duan, Xujun; Liao, Wei; Chen, Huafu

    2018-05-01

    Traditional task-evoked brain activations are based on detection and estimation of signal change from the mean signal. By contrast, the low-frequency steady-state brain response (lfSSBR) reflects frequency-tagging activity at the fundamental frequency of the task presentation and its harmonics. Compared to the activity at these resonant frequencies, brain responses at nonresonant frequencies are largely unknown. Additionally, because the lfSSBR is defined by power change, we hypothesize using Parseval's theorem that the power change reflects brain signal variability rather than the change of mean signal. Using a face recognition task, we observed power increase at the fundamental frequency (0.05 Hz) and two harmonics (0.1 and 0.15 Hz) and power decrease within the infra-slow frequency band ( .955) of their spatial distribution and brain-behavior relationship at all frequency bands. Additionally, the reallocation of finite energy was observed across various brain regions and frequency bands, forming a particular spatiotemporal pattern. Overall, results from this study strongly suggest that frequency-specific power and variability may measure the same underlying brain activity and that these results may shed light on different mechanisms between lfSSBR and brain activation, and spatiotemporal characteristics of energy reallocation induced by cognitive tasks. © 2018 Wiley Periodicals, Inc.

  12. Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus.

    Directory of Open Access Journals (Sweden)

    Roland Frey

    Full Text Available Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0 and a high (g0 fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0. Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female captive dholes (Cuon alpinus and for 2 (1 male, 1 female wild red fox (Vulpes vulpes. In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.

  13. Fundamental deficits of auditory perception in Wernicke's aphasia.

    Science.gov (United States)

    Robson, Holly; Grube, Manon; Lambon Ralph, Matthew A; Griffiths, Timothy D; Sage, Karen

    2013-01-01

    This work investigates the nature of the comprehension impairment in Wernicke's aphasia (WA), by examining the relationship between deficits in auditory processing of fundamental, non-verbal acoustic stimuli and auditory comprehension. WA, a condition resulting in severely disrupted auditory comprehension, primarily occurs following a cerebrovascular accident (CVA) to the left temporo-parietal cortex. Whilst damage to posterior superior temporal areas is associated with auditory linguistic comprehension impairments, functional-imaging indicates that these areas may not be specific to speech processing but part of a network for generic auditory analysis. We examined analysis of basic acoustic stimuli in WA participants (n = 10) using auditory stimuli reflective of theories of cortical auditory processing and of speech cues. Auditory spectral, temporal and spectro-temporal analysis was assessed using pure-tone frequency discrimination, frequency modulation (FM) detection and the detection of dynamic modulation (DM) in "moving ripple" stimuli. All tasks used criterion-free, adaptive measures of threshold to ensure reliable results at the individual level. Participants with WA showed normal frequency discrimination but significant impairments in FM and DM detection, relative to age- and hearing-matched controls at the group level (n = 10). At the individual level, there was considerable variation in performance, and thresholds for both FM and DM detection correlated significantly with auditory comprehension abilities in the WA participants. These results demonstrate the co-occurrence of a deficit in fundamental auditory processing of temporal and spectro-temporal non-verbal stimuli in WA, which may have a causal contribution to the auditory language comprehension impairment. Results are discussed in the context of traditional neuropsychology and current models of cortical auditory processing. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. High accuracy line positions of the ν 1 fundamental band of 14 N 2 16 O

    KAUST Repository

    Alsaif, Bidoor; Lamperti, Marco; Gatti, Davide; Laporta, Paolo; Fermann, Martin; Farooq, Aamir; Lyulin, Oleg; Campargue, Alain; Marangoni, Marco

    2018-01-01

    The ν1 fundamental band of N2O is examined by a novel spectrometer that relies on the frequency locking of an external-cavity quantum cascade laser around 7.8 μm to a near-infrared Tm:based frequency comb at 1.9 μm. Due to the large tunability

  15. Automatic frequency control system for driving a linear accelerator

    International Nuclear Information System (INIS)

    Helgesson, A.L.

    1976-01-01

    An automatic frequency control system is described for maintaining the drive frequency applied to a linear accelerator to produce maximum particle output from the accelerator. The particle output amplitude is measured and the frequency of the radio frequency source powering the linear accelerator is adjusted to maximize particle output amplitude

  16. 6th International Conference on Trapped Charged Particles and Fundamental Physics

    CERN Document Server

    Schury, Peter; Ichikawa, Yuichi

    2017-01-01

    This volume presents the proceedings of the International Conference on Trapped Charged Particles and Fundamental Physics (TCP 14). It presents recent developments in the theoretical and experimental research on trapped charged particles and related fundamental physics and applications. The content has been divided topic-wise covering basic questions of Fundamental Physics, Quantum and QED Effects, Plasmas and Collective Behavior and Anti-Hydrogen. More technical issues include Storage Ring Physics, Precision Spectroscopy and Frequency Standards, Highly Charged Ions in Traps, Traps for Radioactive Isotopes and New Techniques and Facilities. An applied aspect of ion trapping is discussed in section devoted to Applications of Particle Trapping including Quantum Information and Processing. Each topic has a more general introduction, but also more detailed contributions are included. A selection of contributions exemplifies the interdisciplinary nature of the research on trapped charged particles worldwide. Repri...

  17. Direct maximum parsimony phylogeny reconstruction from genotype data.

    Science.gov (United States)

    Sridhar, Srinath; Lam, Fumei; Blelloch, Guy E; Ravi, R; Schwartz, Russell

    2007-12-05

    Maximum parsimony phylogenetic tree reconstruction from genetic variation data is a fundamental problem in computational genetics with many practical applications in population genetics, whole genome analysis, and the search for genetic predictors of disease. Efficient methods are available for reconstruction of maximum parsimony trees from haplotype data, but such data are difficult to determine directly for autosomal DNA. Data more commonly is available in the form of genotypes, which consist of conflated combinations of pairs of haplotypes from homologous chromosomes. Currently, there are no general algorithms for the direct reconstruction of maximum parsimony phylogenies from genotype data. Hence phylogenetic applications for autosomal data must therefore rely on other methods for first computationally inferring haplotypes from genotypes. In this work, we develop the first practical method for computing maximum parsimony phylogenies directly from genotype data. We show that the standard practice of first inferring haplotypes from genotypes and then reconstructing a phylogeny on the haplotypes often substantially overestimates phylogeny size. As an immediate application, our method can be used to determine the minimum number of mutations required to explain a given set of observed genotypes. Phylogeny reconstruction directly from unphased data is computationally feasible for moderate-sized problem instances and can lead to substantially more accurate tree size inferences than the standard practice of treating phasing and phylogeny construction as two separate analysis stages. The difference between the approaches is particularly important for downstream applications that require a lower-bound on the number of mutations that the genetic region has undergone.

  18. Direct maximum parsimony phylogeny reconstruction from genotype data

    Directory of Open Access Journals (Sweden)

    Ravi R

    2007-12-01

    Full Text Available Abstract Background Maximum parsimony phylogenetic tree reconstruction from genetic variation data is a fundamental problem in computational genetics with many practical applications in population genetics, whole genome analysis, and the search for genetic predictors of disease. Efficient methods are available for reconstruction of maximum parsimony trees from haplotype data, but such data are difficult to determine directly for autosomal DNA. Data more commonly is available in the form of genotypes, which consist of conflated combinations of pairs of haplotypes from homologous chromosomes. Currently, there are no general algorithms for the direct reconstruction of maximum parsimony phylogenies from genotype data. Hence phylogenetic applications for autosomal data must therefore rely on other methods for first computationally inferring haplotypes from genotypes. Results In this work, we develop the first practical method for computing maximum parsimony phylogenies directly from genotype data. We show that the standard practice of first inferring haplotypes from genotypes and then reconstructing a phylogeny on the haplotypes often substantially overestimates phylogeny size. As an immediate application, our method can be used to determine the minimum number of mutations required to explain a given set of observed genotypes. Conclusion Phylogeny reconstruction directly from unphased data is computationally feasible for moderate-sized problem instances and can lead to substantially more accurate tree size inferences than the standard practice of treating phasing and phylogeny construction as two separate analysis stages. The difference between the approaches is particularly important for downstream applications that require a lower-bound on the number of mutations that the genetic region has undergone.

  19. Relativities of fundamentality

    Science.gov (United States)

    McKenzie, Kerry

    2017-08-01

    S-dualities have been held to have radical implications for our metaphysics of fundamentality. In particular, it has been claimed that they make the fundamentality status of a physical object theory-relative in an important new way. But what physicists have had to say on the issue has not been clear or consistent, and in particular seems to be ambiguous between whether S-dualities demand an anti-realist interpretation of fundamentality talk or merely a revised realism. This paper is an attempt to bring some clarity to the matter. After showing that even antecedently familiar fundamentality claims are true only relative to a raft of metaphysical, physical, and mathematical assumptions, I argue that the relativity of fundamentality inherent in S-duality nevertheless represents something new, and that part of the reason for this is that it has both realist and anti-realist implications for fundamentality talk. I close by discussing the broader significance that S-dualities have for structuralist metaphysics and for fundamentality metaphysics more generally.

  20. FUNDAMENTAL PROPERTIES OF STARS USING ASTEROSEISMOLOGY FROM KEPLER AND CoRoT AND INTERFEROMETRY FROM THE CHARA ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Huber, D.; Ireland, M. J.; Bedding, T. R.; Maestro, V.; White, T. R. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Brandao, I. M.; Sousa, S. G.; Cunha, M. S. [Centro de Astrofo Latin-Small-Letter-Dotless-I sica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, P-4150-762 Porto (Portugal); Piau, L. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48823-2320 (United States); Bruntt, H.; Aguirre, V. Silva; Christensen-Dalsgaard, J. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Casagrande, L. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, The Australian National University, ACT 2611 (Australia); Molenda-Zakowicz, J. [Astronomical Institute of the University of Wroclaw, ul. Kopernika 11, 51-622 Wroclaw (Poland); Barclay, T. [Bay Area Environmental Research Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Burke, C. J. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Chaplin, W. J. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); De Ridder, J. [Instituut voor Sterrenkunde, K. U. Leuven, B-3001 Leuven (Belgium); Farrington, C. D. [Center for High Angular Resolution Astronomy, Georgia State University, P.O. Box 3969, Atlanta, GA 30302 (United States); Frasca, A., E-mail: daniel.huber@nasa.gov [INAF Osservatorio Astrofisico di Catania, I-95123 Catania (Italy); and others

    2012-11-20

    We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric angular diameters, Hipparcos parallaxes, asteroseismic densities, bolometric fluxes, and high-resolution spectroscopy, we derive a full set of near-model-independent fundamental properties for the sample. We first use these properties to test asteroseismic scaling relations for the frequency of maximum power ({nu}{sub max}) and the large frequency separation ({Delta}{nu}). We find excellent agreement within the observational uncertainties, and empirically show that simple estimates of asteroseismic radii for main-sequence stars are accurate to {approx}< 4%. We furthermore find good agreement of our measured effective temperatures with spectroscopic and photometric estimates with mean deviations for stars between T {sub eff} = 4600-6200 K of -22 {+-} 32 K (with a scatter of 97 K) and -58 {+-} 31 K (with a scatter of 93 K), respectively. Finally, we present a first comparison with evolutionary models, and find differences between observed and theoretical properties for the metal-rich main-sequence star HD 173701. We conclude that the constraints presented in this study will have strong potential for testing stellar model physics, in particular when combined with detailed modeling of individual oscillation frequencies.

  1. Transverse kick in misaligned traveling wave structures driven at the fundamental mode

    International Nuclear Information System (INIS)

    Whittum, D.H.

    1998-04-01

    Fabrication errors in traveling wave structures result in non-axisymmetric RF fields that couple to the rf drive at the fundamental mode frequency. The authors calculate the excitation of the dipole mode and the integrated effect on the beam, using the thin iris and small hole approximation

  2. A Comparative Frequency Analysis of Maximum Daily Rainfall for a SE Asian Region under Current and Future Climate Conditions

    Directory of Open Access Journals (Sweden)

    Velautham Daksiya

    2017-01-01

    Full Text Available The impact of changing climate on the frequency of daily rainfall extremes in Jakarta, Indonesia, is analysed and quantified. The study used three different models to assess the changes in rainfall characteristics. The first method involves the use of the weather generator LARS-WG to quantify changes between historical and future daily rainfall maxima. The second approach consists of statistically downscaling general circulation model (GCM output based on historical empirical relationships between GCM output and station rainfall. Lastly, the study employed recent statistically downscaled global gridded rainfall projections to characterize climate change impact rainfall structure. Both annual and seasonal rainfall extremes are studied. The results show significant changes in annual maximum daily rainfall, with an average increase as high as 20% in the 100-year return period daily rainfall. The uncertainty arising from the use of different GCMs was found to be much larger than the uncertainty from the emission scenarios. Furthermore, the annual and wet seasonal analyses exhibit similar behaviors with increased future rainfall, but the dry season is not consistent across the models. The GCM uncertainty is larger in the dry season compared to annual and wet season.

  3. Single frequency Nd:YLF and Nd:YVO4 laser in the red emission

    International Nuclear Information System (INIS)

    Camargo, Fabiola de Almeida

    2010-01-01

    All solid-state continuous-wave (cw) narrow emission linewidth and tunable red lasers are convenient alternative sources to bulky and expensive dye-lasers for high precision laser spectroscopy. Single-frequency operation of diode-pumped Nd:YLiF 4 and Nd:YVO 4 cw ring lasers were investigated in the 1.32 - 1.34μm range, together with their intracavity second-harmonic generation (SHG) to the red spectral range (0.65 - 0.67μm) using either BiB 3 O 6 (BiBO) or periodically-poled KTiOPO 4 (ppKTP) crystals. We report on such a single-end diode-pumped Nd:YVO 4 unidirectional red ring laser containing a type-I cut BiBO nonlinear crystal, yielding a record of 680 mW of single-longitudinal mode (SLM) red output power at 671.1nm without any intra-cavity etalon. For smooth SLM wavelength tuning over the full gain bandwidth (∼4 nm), a partially-coated (R = 40%) 100μm-thin etalon was found necessary, reducing the maximum SLM power (at 671.15 nm) to 380 mW. At 1342.5nm and with a T = 2% transmission output coupler, the laser provided an optimal 1.5W of single-frequency power. We demonstrate also optimal intracavity SHG of a Nd:YLF ring laser in the π- polarization (λ = 1321.5nm) using a ppKTP. The laser yielded 1.4 W of single frequency red power at 660.5 nm, as much as the maximum fundamental power that can be extracted from the resonator using an optimal output coupler. With a partially coated (R = 25%) thin etalon, the laser was tunable over Δλ∼ 1.6nm. (author)

  4. Maximum Likelihood Approach for RFID Tag Set Cardinality Estimation with Detection Errors

    DEFF Research Database (Denmark)

    Nguyen, Chuyen T.; Hayashi, Kazunori; Kaneko, Megumi

    2013-01-01

    Abstract Estimation schemes of Radio Frequency IDentification (RFID) tag set cardinality are studied in this paper using Maximum Likelihood (ML) approach. We consider the estimation problem under the model of multiple independent reader sessions with detection errors due to unreliable radio...... is evaluated under dierent system parameters and compared with that of the conventional method via computer simulations assuming flat Rayleigh fading environments and framed-slotted ALOHA based protocol. Keywords RFID tag cardinality estimation maximum likelihood detection error...

  5. On the interpretation and relevance of the Fundamental Theorem of Natural Selection.

    Science.gov (United States)

    Ewens, Warren J; Lessard, Sabin

    2015-09-01

    The attempt to understand the statement, and then to find the interpretation, of Fisher's "Fundamental Theorem of Natural Selection" caused problems for generations of population geneticists. Price's (1972) paper was the first to lead to an understanding of the statement of the theorem. The theorem shows (in the discrete-time case) that the so-called "partial change" in mean fitness of a population between a parental generation and an offspring generation is the parental generation additive genetic variance in fitness divided by the parental generation mean fitness. In the continuous-time case the partial rate of change in mean fitness is equal to the parental generation additive genetic variance in fitness with no division by the mean fitness. This "partial change" has been interpreted by some as the change in mean fitness due to changes in gene frequency, and by others as the change in mean fitness due to natural selection. (Fisher variously used both interpretations.) In this paper we discuss these interpretations of the theorem. We indicate why we are unhappy with both. We also discuss the long-term relevance of the Fundamental Theorem of Natural Selection, again reaching a negative assessment. We introduce and discuss the concept of genic evolutionary potential. We finally review an optimizing theorem that involves changes in gene frequency, the additive genetic variance in fitness and the mean fitness itself, all of which are involved in the Fundamental Theorem of Natural Selection, and which is free of the difficulties in interpretation of the Fundamental Theorem of Natural Selection. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. ANALYTICAL CALCULATION OF THE BASIC ELECTROMAGNETIC LOSSES OF THE ENERGY OF THE FREQUENCY-REGULATED ASYNCHRONOUS ENGINE IN POSITIONING

    Directory of Open Access Journals (Sweden)

    V. O. Volkov

    2018-02-01

    Full Text Available Purpose. Obtaining analytical dependencies for the calculation of the main electromagnetic energy losses of a frequency-controlled induction motor in positioning modes with small displacements for various types (linear, parabolic and quasi-optimal of its velocity variation. Methodology. Similarity methods, differential and integral calculus, analytical interpolation, mathematical analysis. Findings. Analytical dependencies for calculation of current electromagnetic power losses and basic electromagnetic energy losses of a frequency-controlled asynchronous motor in the modes of positioning with small displacements for various types (linear, parabolic and quasi-optimal of its velocity are obtained. A universal form of the analytical dependence for calculating the optimal acceleration and deceleration times for a frequency-controlled asynchronous motor for positioning with small displacements, corresponding to minimization of the main electromagnetic energy losses of this engine with the indicated positioning for various species (linear, parabolic and quasi-optimal, is obtained. A comparative quantitative assessment of the change is made: the optimum values of the main electromagnetic energy losses of the frequency-controlled asynchronous engine and the corresponding maximum speed and optimal acceleration and deceleration times, in the function of the set prescribed small displacements for the various engine speed trajectories under consideration. Originality. For the first time, analytical dependencies for the calculation of the main electromagnetic energy losses of a frequency-controlled asynchronous motor are obtained for positioning with small displacements as a function of the set values of the movement of the motor shaft and the set values of its acceleration and deceleration times for the specified specified displacements. For the first time, dependences are obtained for a quantitative estimate of the minimum fundamental electromagnetic

  7. Potential role of motion for enhancing maximum output energy of triboelectric nanogenerator

    Science.gov (United States)

    Byun, Kyung-Eun; Lee, Min-Hyun; Cho, Yeonchoo; Nam, Seung-Geol; Shin, Hyeon-Jin; Park, Seongjun

    2017-07-01

    Although triboelectric nanogenerator (TENG) has been explored as one of the possible candidates for the auxiliary power source of portable and wearable devices, the output energy of a TENG is still insufficient to charge the devices with daily motion. Moreover, the fundamental aspects of the maximum possible energy of a TENG related with human motion are not understood systematically. Here, we confirmed the possibility of charging commercialized portable and wearable devices such as smart phones and smart watches by utilizing the mechanical energy generated by human motion. We confirmed by theoretical extraction that the maximum possible energy is related with specific form factors of a TENG. Furthermore, we experimentally demonstrated the effect of human motion in an aspect of the kinetic energy and impulse using varying velocity and elasticity, and clarified how to improve the maximum possible energy of a TENG. This study gives insight into design of a TENG to obtain a large amount of energy in a limited space.

  8. Potential role of motion for enhancing maximum output energy of triboelectric nanogenerator

    Directory of Open Access Journals (Sweden)

    Kyung-Eun Byun

    2017-07-01

    Full Text Available Although triboelectric nanogenerator (TENG has been explored as one of the possible candidates for the auxiliary power source of portable and wearable devices, the output energy of a TENG is still insufficient to charge the devices with daily motion. Moreover, the fundamental aspects of the maximum possible energy of a TENG related with human motion are not understood systematically. Here, we confirmed the possibility of charging commercialized portable and wearable devices such as smart phones and smart watches by utilizing the mechanical energy generated by human motion. We confirmed by theoretical extraction that the maximum possible energy is related with specific form factors of a TENG. Furthermore, we experimentally demonstrated the effect of human motion in an aspect of the kinetic energy and impulse using varying velocity and elasticity, and clarified how to improve the maximum possible energy of a TENG. This study gives insight into design of a TENG to obtain a large amount of energy in a limited space.

  9. Laser Spectroscopy and Frequency Combs

    International Nuclear Information System (INIS)

    Hänsch, Theodor W; Picqué, Nathalie

    2013-01-01

    The spectrum of a frequency comb, commonly generated by a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. The invention of the frequency comb technique has been motivated by precision laser spectroscopy of the simple hydrogen atom. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose. Laser combs are becoming powerful instruments for broadband molecular spectroscopy by dramatically improving the resolution and recording speed of Fourier spectrometers and by creating new opportunities for highly multiplexed nonlinear spectroscopy, such as two-photon spectroscopy or coherent Raman spectroscopy. Other emerging applications of frequency combs range from fundamental research in astronomy, chemistry, or attosecond science to telecommunications and satellite navigation

  10. Fundamental absorption edge of CdP2 single crystals

    International Nuclear Information System (INIS)

    Bondar', G.I.; Koval', V.S.; Kurik, M.V.

    1986-01-01

    Fundamental absorption edge of tetragonal CdP 2 crystals is investigated within the temperature range of 4.2-293 K. The crystals are grown by the Bridgman methods and resublimation methods and possess different degree of perfection and purity. In perfect CdP 2 crystals with small concentration of impurities in the region of K > 20 cm -1 the shape of the absorption edge spectrum is described by the Urbach rule. The Urbach rule parameters are defined. The electron-phonon interaction is shown to be the determinant at K > 20 cm -1 and the direct vertical transition is observed. A slight additional absorption with maximum at 2.163 eV within the range of K -1 and at T ≤ 50 is associated with transition from shallow acceptor level to the conduction zone. The impurity leads to the shift of the fundamental absorption edge to the long-wavelength side and diffusion of electrons on impurities is resulted

  11. Simple model for low-frequency guitar function

    DEFF Research Database (Denmark)

    Christensen, Ove; Vistisen, Bo B.

    1980-01-01

    - frequency guitar function. The model predicts frequency responce of sound pressure and top plate mobility which are in close quantitative agreement with experimental responses. The absolute sound pressure level and mobility level are predicted to within a few decibels, and the equivalent piston area......The frequency response of sound pressure and top plate mobility is studied around the two first resonances of the guitar. These resonances are shown to result from a coupling between the fundamental top plate mode and the Helmholtz resonance of the cavity. A simple model is proposed for low...

  12. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    International Nuclear Information System (INIS)

    Ju, S; Chae, S H; Choi, Y; Jun, S; Park, S M; Lee, S; Ji, C-H; Lee, H W

    2013-01-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken

  13. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    Science.gov (United States)

    Ju, S.; Chae, S. H.; Choi, Y.; Jun, S.; Park, S. M.; Lee, S.; Lee, H. W.; Ji, C.-H.

    2013-12-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken.

  14. Noise and physical limits to maximum resolution of PET images

    Energy Technology Data Exchange (ETDEWEB)

    Herraiz, J.L.; Espana, S. [Dpto. Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Vicente, E.; Vaquero, J.J.; Desco, M. [Unidad de Medicina y Cirugia Experimental, Hospital GU ' Gregorio Maranon' , E-28007 Madrid (Spain); Udias, J.M. [Dpto. Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)], E-mail: jose@nuc2.fis.ucm.es

    2007-10-01

    In this work we show that there is a limit for the maximum resolution achievable with a high resolution PET scanner, as well as for the best signal-to-noise ratio, which are ultimately related to the physical effects involved in the emission and detection of the radiation and thus they cannot be overcome with any particular reconstruction method. These effects prevent the spatial high frequency components of the imaged structures to be recorded by the scanner. Therefore, the information encoded in these high frequencies cannot be recovered by any reconstruction technique. Within this framework, we have determined the maximum resolution achievable for a given acquisition as a function of data statistics and scanner parameters, like the size of the crystals or the inter-crystal scatter. In particular, the noise level in the data as a limitation factor to yield high-resolution images in tomographs with small crystal sizes is outlined. These results have implications regarding how to decide the optimal number of voxels of the reconstructed image or how to design better PET scanners.

  15. Noise and physical limits to maximum resolution of PET images

    International Nuclear Information System (INIS)

    Herraiz, J.L.; Espana, S.; Vicente, E.; Vaquero, J.J.; Desco, M.; Udias, J.M.

    2007-01-01

    In this work we show that there is a limit for the maximum resolution achievable with a high resolution PET scanner, as well as for the best signal-to-noise ratio, which are ultimately related to the physical effects involved in the emission and detection of the radiation and thus they cannot be overcome with any particular reconstruction method. These effects prevent the spatial high frequency components of the imaged structures to be recorded by the scanner. Therefore, the information encoded in these high frequencies cannot be recovered by any reconstruction technique. Within this framework, we have determined the maximum resolution achievable for a given acquisition as a function of data statistics and scanner parameters, like the size of the crystals or the inter-crystal scatter. In particular, the noise level in the data as a limitation factor to yield high-resolution images in tomographs with small crystal sizes is outlined. These results have implications regarding how to decide the optimal number of voxels of the reconstructed image or how to design better PET scanners

  16. Investigation on maximum transition temperature of phonon mediated superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Fusui, L; Yi, S; Yinlong, S [Physics Department, Beijing University (CN)

    1989-05-01

    Three model effective phonon spectra are proposed to get plots of {ital T}{sub {ital c}}-{omega} adn {lambda}-{omega}. It can be concluded that there is no maximum limit of {ital T}{sub {ital c}} in phonon mediated superconductivity for reasonable values of {lambda}. The importance of high frequency LO phonon is also emphasized. Some discussions on high {ital T}{sub {ital c}} are given.

  17. An examination of the spectral class low frequency limit for helicopters

    Science.gov (United States)

    2011-01-01

    Currently, INM and AEDT do not use spectral data below 50 Hz in their noise computations. However, helicopter rotor rotational noise is dominant below 50Hz, with a fundamental frequency at the blade-pass frequency (BPF) and harmonics at integer multi...

  18. Digital Fourier analysis fundamentals

    CERN Document Server

    Kido, Ken'iti

    2015-01-01

    This textbook is a thorough, accessible introduction to digital Fourier analysis for undergraduate students in the sciences. Beginning with the principles of sine/cosine decomposition, the reader walks through the principles of discrete Fourier analysis before reaching the cornerstone of signal processing: the Fast Fourier Transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Fundamentals" includes practice problems and thorough Appendices for the advanced reader. As a special feature, the book includes interactive applets (available online) that mirror the illustrations.  These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. For example, a real sine signal can be treated as a sum of clockwise and counter-clockwise rotating vectors. The applet illustration included with the book animates the rotating vectors and the resulting sine signal. By changing parameters such as amplitude and frequency, the reader ca...

  19. A cervid vocal fold model suggests greater glottal efficiency in calling at high frequencies.

    Directory of Open Access Journals (Sweden)

    Ingo R Titze

    2010-08-01

    Full Text Available Male Rocky Mountain elk (Cervus elaphus nelsoni produce loud and high fundamental frequency bugles during the mating season, in contrast to the male European Red Deer (Cervus elaphus scoticus who produces loud and low fundamental frequency roaring calls. A critical step in understanding vocal communication is to relate sound complexity to anatomy and physiology in a causal manner. Experimentation at the sound source, often difficult in vivo in mammals, is simulated here by a finite element model of the larynx and a wave propagation model of the vocal tract, both based on the morphology and biomechanics of the elk. The model can produce a wide range of fundamental frequencies. Low fundamental frequencies require low vocal fold strain, but large lung pressure and large glottal flow if sound intensity level is to exceed 70 dB at 10 m distance. A high-frequency bugle requires both large muscular effort (to strain the vocal ligament and high lung pressure (to overcome phonation threshold pressure, but at least 10 dB more intensity level can be achieved. Glottal efficiency, the ration of radiated sound power to aerodynamic power at the glottis, is higher in elk, suggesting an advantage of high-pitched signaling. This advantage is based on two aspects; first, the lower airflow required for aerodynamic power and, second, an acoustic radiation advantage at higher frequencies. Both signal types are used by the respective males during the mating season and probably serve as honest signals. The two signal types relate differently to physical qualities of the sender. The low-frequency sound (Red Deer call relates to overall body size via a strong relationship between acoustic parameters and the size of vocal organs and body size. The high-frequency bugle may signal muscular strength and endurance, via a 'vocalizing at the edge' mechanism, for which efficiency is critical.

  20. Fungic microflora of Panicum maximum and Styosanthes spp. commercial seed / Microflora fúngica de sementes comerciais de Panicum maximum e Stylosanthes spp.

    Directory of Open Access Journals (Sweden)

    Larissa Rodrigues Fabris

    2010-09-01

    Full Text Available The sanitary quality of 26 lots commercial seeds of tropical forages, produced in different regions (2004-05 and 2005-06 was analyzed. The lots were composed of seeds of Panicum maximum ('Massai', 'Mombaça' e 'Tanzânia' and stylo ('Estilosantes Campo Grande' - ECG. Additionally, seeds of two lots of P. maximum for exportation were analyzed. The blotter test was used, at 20ºC under alternating light and darkness in a 12 h photoperiod, for seven days. The Aspergillus, Cladosporium and Rhizopus genus consisted the secondary or saprophytes fungi (FSS with greatest frequency in P. maximum lots. In general, there was low incidence of these fungus in the seeds. In relation to pathogenic fungi (FP, it was detected high frequency of contaminated lots by Bipolaris, Curvularia, Fusarium and Phoma genus. Generally, there was high incidence of FP in P. maximum seeds. The occurrence of Phoma sp. was hight, because in 81% of the lots showed incidence superior to 50%. In 'ECG' seeds it was detected FSS (Aspergillus, Cladosporium, and Penicillium genus and FP (Bipolaris, Curvularia, Fusarium and Phoma genus, usually, in low incidence. FSS and FP were associated to P. maximum seeds for exportation, with significant incidence in some cases. The results indicated that there was a limiting factor in all producer regions regarding sanitary quality of the seeds.Sementes comerciais de forrageiras tropicais, pertencente a 26 lotes produzidos em diferentes regiões (safras 2004-05 e 2005-06, foram avaliadas quanto à sanidade. Foram analisadas sementes de cultivares de Panicum maximum (Massai, Mombaça e Tanzânia e de estilosantes (Estilosantes Campo Grande – ECG. Adicionalmente, avaliou-se a qualidade sanitária de dois lotes de sementes de P. maximum destinados à exportação. Para isso, as sementes foram submetidas ao teste de papel de filtro em gerbox, os quais foram incubados a 20ºC, com fotoperíodo de 12 h, durante sete dias. Os fungos saprófitos ou

  1. Fundamentalism and science

    Directory of Open Access Journals (Sweden)

    Massimo Pigliucci

    2006-06-01

    Full Text Available The many facets of fundamentalism. There has been much talk about fundamentalism of late. While most people's thought on the topic go to the 9/11 attacks against the United States, or to the ongoing war in Iraq, fundamentalism is affecting science and its relationship to society in a way that may have dire long-term consequences. Of course, religious fundamentalism has always had a history of antagonism with science, and – before the birth of modern science – with philosophy, the age-old vehicle of the human attempt to exercise critical thinking and rationality to solve problems and pursue knowledge. “Fundamentalism” is defined by the Oxford Dictionary of the Social Sciences1 as “A movement that asserts the primacy of religious values in social and political life and calls for a return to a 'fundamental' or pure form of religion.” In its broadest sense, however, fundamentalism is a form of ideological intransigence which is not limited to religion, but includes political positions as well (for example, in the case of some extreme forms of “environmentalism”.

  2. Fundamental safety principles. Safety fundamentals

    International Nuclear Information System (INIS)

    2007-01-01

    This publication states the fundamental safety objective and ten associated safety principles, and briefly describes their intent and purpose. The fundamental safety objective - to protect people and the environment from harmful effects of ionizing radiation - applies to all circumstances that give rise to radiation risks. The safety principles are applicable, as relevant, throughout the entire lifetime of all facilities and activities - existing and new - utilized for peaceful purposes, and to protective actions to reduce existing radiation risks. They provide the basis for requirements and measures for the protection of people and the environment against radiation risks and for the safety of facilities and activities that give rise to radiation risks, including, in particular, nuclear installations and uses of radiation and radioactive sources, the transport of radioactive material and the management of radioactive waste

  3. Fundamental safety principles. Safety fundamentals

    International Nuclear Information System (INIS)

    2006-01-01

    This publication states the fundamental safety objective and ten associated safety principles, and briefly describes their intent and purpose. The fundamental safety objective - to protect people and the environment from harmful effects of ionizing radiation - applies to all circumstances that give rise to radiation risks. The safety principles are applicable, as relevant, throughout the entire lifetime of all facilities and activities - existing and new - utilized for peaceful purposes, and to protective actions to reduce existing radiation risks. They provide the basis for requirements and measures for the protection of people and the environment against radiation risks and for the safety of facilities and activities that give rise to radiation risks, including, in particular, nuclear installations and uses of radiation and radioactive sources, the transport of radioactive material and the management of radioactive waste

  4. EFFECT OF FARM SIZE AND FREQUENCY OF CUTTING ON ...

    African Journals Online (AJOL)

    EFFECT OF FARM SIZE AND FREQUENCY OF CUTTING ON OUTPUT OF ... the use of Ordinary Least Square (OLS) estimation technique was used in analyzing ... frequency of cutting that would produce maximum output of the vegetable as ...

  5. On positivity of time-frequency distributions.

    NARCIS (Netherlands)

    Janssen, A.J.E.M.; Claasen, T.A.C.M.

    1985-01-01

    Consideration is given to the problem of how to regard the fundamental impossibility with time-frequency energy distributions of Cohen's class always to be nonnegative and, at the same time, to have correct marginal distributions. It is shown that the Wigner distribution is the only member of a

  6. Call for papers for special issue of Journal of Molecular Spectroscopy focusing on "Frequency-comb spectroscopy"

    Science.gov (United States)

    Foltynowicz, Aleksandra; Picqué, Nathalie; Ye, Jun

    2018-05-01

    Frequency combs are becoming enabling tools for many applications in science and technology, beyond the original purpose of frequency metrology of simple atoms. The precisely evenly spaced narrow lines of a laser frequency comb inspire intriguing approaches to molecular spectroscopy, designed and implemented by a growing community of scientists. Frequency-comb spectroscopy advances the frontiers of molecular physics across the entire electro-magnetic spectrum. Used as frequency rulers, frequency combs enable absolute frequency measurements and precise line shape studies of molecular transitions, for e.g. tests of fundamental physics and improved determination of fundamental constants. As light sources interrogating the molecular samples, they dramatically improve the resolution, precision, sensitivity and acquisition time of broad spectral-bandwidth spectroscopy and open up new opportunities and applications at the leading edge of molecular spectroscopy and sensing.

  7. Astronomers Gain Clues About Fundamental Physics

    Science.gov (United States)

    2005-12-01

    superstring theory and extra dimensions in spacetime calling for the "constants" to change over time, he said. The astronomers used the GBT to detect and study radio emissions at four specific frequencies between 1612 MHz and 1720 MHz coming from hydroxyl (OH) molecules in a galaxy more than 6 billion light-years from Earth, seen as it was at roughly half the Universe's current age. Each of the four frequencies represents a specific change in the energy level of the molecule. The exact frequency emitted or absorbed when the molecule undergoes a transition from one energy level to another depends on the values of the fundamental physical constants. However, each of the four frequencies studied in the OH molecule will react differently to a change in the constants. That difference is what the astronomers sought to detect using the GBT, which, Kanekar explained, is the ideal telescope for this work because of its technical capabilities and its location in the National Radio Quiet Zone, where radio interference is at a minimum. "We can place very tight limits on changes in the physical constants by studying the behavior of these OH molecules at a time when the Universe was only about half its current age, and comparing this result to how the molecules behave today in the laboratory," said Karl Menten of the Max-Planck Institute for Radioastronomy in Germany. Wetterich, a theorist, welcomes the new capability, saying the observational method "seems very promising to obtain perhaps the most accurate values for such possible time changes of the constants." He pointed out that, while some theoretical models call for the constants to change only in the early moments after the Big Bang, models of the recently-discovered, mysterious "dark energy" that seems to be accelerating the Universe's expansion call for changes "even in the last couple of billion years." "Only observations can tell," he said. This research ties together the theoretical and observational work of Wetterich and

  8. How-to-Do-It: Hands-on Activity for Mitosis, Meiosis and the Fundamentals of Heredity.

    Science.gov (United States)

    Taylor, Mark F.

    1988-01-01

    Described is an exercise which uses inexpensive and easy-to-make materials to demonstrate the basic fundamentals of heredity. Discusses two approaches using a hypothetical insert to demonstrate inheritance, mitosis, meiosis, and genotypic and phenotypic frequencies. (CW)

  9. Estimation of allele frequency and association mapping using next-generation sequencing data

    DEFF Research Database (Denmark)

    Kim, Su Yeon; Lohmueller, Kirk E; Albrechtsen, Anders

    2011-01-01

    Estimation of allele frequency is of fundamental importance in population genetic analyses and in association mapping. In most studies using next-generation sequencing, a cost effective approach is to use medium or low-coverage data (e.g., frequency estimation...

  10. Escola de ensino fundamental(s em movimento – movimento na escola de ensino fundamental

    Directory of Open Access Journals (Sweden)

    Reiner Hildebrandt-Stramann

    2007-12-01

    Full Text Available A escola de ensino fundamental na Alemanha sofreu movimento nos últimos 15 anos, porque, entre outros motivos, entrou movimento nessas escolas. Esse jogo de palavras chama atenção a duas linhas de trabalho que determinam a discussão na atual pedagogia escolar. O presente trabalho revela essas duas perspectivas. Uma das linhas está relacionada ao atual processo de mudança na pedagogia escolar. Essa prediz que a escola de ensino fundamental deve ser um lugar de aprendizagem e de vivência para as crianças. A outra linha tem a ver com o jogo de palavras ancorado a esses processos da pedagogia do movimento, a qual ganha cada vez maiores dimensões. A escola de ensino fundamental deve ser vista sob a perspectiva do movimento e transformada em um lugar de movimento.

  11. Fundamentals of thermophotovoltaic energy conversion

    CERN Document Server

    Chubb, Donald L

    2007-01-01

    This is a text book presenting the fundamentals of thermophotovoltaic(TPV) energy conversion suitable for an upper undergraduate or first year graduate course. In addition it can serve as a reference or design aid for engineers developing TPV systems. Mathematica design programs for interference filters and a planar TPV system are included on a CD-Rom disk. Each chapter includes a summary and concludes with a set of problems. The first chapter presents the electromagnetic theory and radiation transfer theory necessary to calculate the optical properties of the components in a TPV optical cavity. Using a simplified model, Chapter 2 develops expressions for the maximum efficiency and power density for an ideal TPV system. The next three chapters consider the three major components in a TPV system; the emitter, filter and photovoltaic(PV) array. Chapter 3 applies the electromagnetic theory and radiation transfer theory presented in Chapter 1 in the calculation of spectral emittance. From the spectral emittance t...

  12. LOW-FREQUENCY OSCILLATIONS IN XTE J1550-564

    International Nuclear Information System (INIS)

    Rao Fengyun; Belloni, Tomaso; Stella, Luigi; Zhang Shuangnan; Li Tipei

    2010-01-01

    We present the results of a timing analysis of the low-frequency quasi-periodic oscillation (QPO) in the Rossi X-Ray Timing Explorer data of the black hole binary XTE J1550-564 during its 1998 outburst. The QPO frequency is observed to vary on timescales between ∼100 s and days, correlated with the count rate contribution from the optically thick accretion disk: we studied this correlation and discuss its influence on the QPO width. In all observations, the quality factors (ν 0 /FWHM) of the fundamental and second harmonic peaks were observed to be consistent, suggesting that the quasi-periodic nature of the oscillation is due to frequency modulation. In addition to the QPO and its harmonic peaks, a new 1.5ν component was detected in the power spectra. This component is broad, with a quality factor of ∼0.6. From this, we argue that the peak observed at half the QPO frequency, usually referred to as 'sub-harmonic', could be the fundamental frequency, leading to the sequence 1:2:3:4. We also studied the energy dependence of the timing features and conclude that the two continuum components observed in the power spectrum, although both more intense at high energies, show a different dependence on energy. At low energies, the lowest-frequency component dominates, while at high energies the higher-frequency one has a higher fractional rms. An interplay between these two components was also observed as a function of their characteristic frequency. In this source, the transition between the low/hard state and the hard-intermediate state appears to be a smooth process.

  13. Nonlinear generation of the fundamental radiation of interplanetary type III radio bursts

    International Nuclear Information System (INIS)

    Chian, A.C.L.; Alves, M.V.

    1988-01-01

    A new generation mechanism of interplanetary type III radio bursts at the fundamental electron plasma frequency is discussed. It is shown that the electromagnetic oscillating two-stream instability, driven by two oppositely propagating Langmuir waves, can account for the experimental observations. In particular, the major difficulties encountered by the previously considered electromagnetic decay instability are removed. 19 references

  14. Improved Reliability of Single-Phase PV Inverters by Limiting the Maximum Feed-in Power

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level...... devices, allowing a quantitative prediction of the power device lifetime. A study case on a 3 kW single-phase PV inverter has demonstrated the advantages of the CPG control in terms of improved reliability.......Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level....... The CPG control strategy is activated only when the DC input power from PV panels exceeds a specific power limit. It enables to limit the maximum feed-in power to the electric grids and also to improve the utilization of PV inverters. As a further study, this paper investigates the reliability performance...

  15. Improved MIMO radar GMTI via cyclic-shift transmission of orthogonal frequency division signals

    Science.gov (United States)

    Li, Fuyou; He, Feng; Dong, Zhen; Wu, Manqing

    2018-05-01

    Minimum detectable velocity (MDV) and maximum detectable velocity are both important in ground moving target indication (GMTI) systems. Smaller MDV can be achieved by longer baseline via multiple-input multiple-output (MIMO) radar. Maximum detectable velocity is decided by blind velocities associated with carrier frequencies, and blind velocities can be mitigated by orthogonal frequency division signals. However, the scattering echoes from different carrier frequencies are independent, which is not good for improving MDV performance. An improved cyclic-shift transmission is applied in MIMO GMTI system in this paper. MDV performance is improved due to the longer baseline, and maximum detectable velocity performance is improved due to the mitigation of blind velocities via multiple carrier frequencies. The signal model for this mode is established, the principle of mitigating blind velocities with orthogonal frequency division signals is presented; the performance of different MIMO GMTI waveforms is analysed; and the performance of different array configurations is analysed. Simulation results by space-time-frequency adaptive processing proves that our proposed method is a valid way to improve GMTI performance.

  16. PATTERNS OF THE MAXIMUM RAINFALL AMOUNTS REGISTERED IN 24 HOURS WITHIN THE OLTENIA PLAIN

    Directory of Open Access Journals (Sweden)

    ALINA VLĂDUŢ

    2012-03-01

    Full Text Available Patterns of the maximum rainfall amounts registered in 24 hours within the Oltenia Plain. The present study aims at rendering the main features of the maximum rainfall amounts registered in 24 h within the Oltenia Plain. We used 30-year time series (1980-2009 for seven meteorological stations. Generally, the maximum amounts in 24 h display the same pattern as the monthly mean amounts, namely higher values in the interval May-October. In terms of mean values, the highest amounts are registered in the western and northern extremity of the plain. The maximum values generally exceed 70 mm at all meteorological stations: D.T. Severin, 224 mm, July 1999; Slatina, 104.8 mm, August 2002; Caracal, 92.2 m, July 1991; Bechet, 80.8 mm, July 2006; Craiova, 77.6 mm, April 2003. During the cold season, there was noticed a greater uniformity all over the plain, due to the cyclonic origin of rainfalls compared to the warm season, when thermal convection is quite active and it triggers local showers. In order to better emphasize the peculiarities of this parameter, we have calculated the frequency on different value classes (eight classes, as well as the probability of appearance of different amounts. Thus, it resulted that the highest frequency (25-35% is held by the first two classes of values (0-10 mm; 10.1-20 mm. The lowest frequency is registered in case of the amounts of more than 100 mm, which generally display a probability of occurrence of less than 1% and only in the western and eastern extremities of the plain.

  17. Fundamental volatility and stock returns : does fundamental volatility explain stock returns?

    OpenAIRE

    Selboe, Guner K.; Virdee, Jaspal Singh

    2017-01-01

    In this thesis, we investigate whether the fundamental uncertainty can explain the crosssection of stock returns. To measure the fundamental uncertainty, we estimate rolling standard deviations and accounting betas of four different fundamentals: revenues, gross profit, earnings and cash flows. The standard deviation and the beta of revenues significantly explain returns in the Fama-Macbeth procedure, but only appears significant among smaller stocks in the portfolio formation ...

  18. W-band push—push monolithic frequency doubler in 1-μm InP DHBT technology

    International Nuclear Information System (INIS)

    Yao Hongfei; Wang Xiantai; Wu Danyu; Su Yongbo; Cao Yuxiong; Ge Ji; Ning Xiaoxi; Jin Zhi

    2013-01-01

    A W-band frequency doubler MMIC is designed and fabricated using 1-μm InP DHBT technology. Active balun is employed to transform the single-ended signal into differential output. Push—push configuration loaded with harmonic resonant network is utilized to acquire the second harmonic frequency. A multi-stage differential structure improves the conversion gain and suppresses the fundamental frequency. The MMIC occupies an area of 0.55 × 0.5 mm 2 with 18 DHBTs integrated. Measurements show that the output power is above 5.8 dBm with the suppression of fundamental frequency below −16 dBc and the conversion gain above 4.7 dB over 75–80 GHz. (semiconductor integrated circuits)

  19. Maximum Temperature Detection System for Integrated Circuits

    Science.gov (United States)

    Frankiewicz, Maciej; Kos, Andrzej

    2015-03-01

    The paper describes structure and measurement results of the system detecting present maximum temperature on the surface of an integrated circuit. The system consists of the set of proportional to absolute temperature sensors, temperature processing path and a digital part designed in VHDL. Analogue parts of the circuit where designed with full-custom technique. The system is a part of temperature-controlled oscillator circuit - a power management system based on dynamic frequency scaling method. The oscillator cooperates with microprocessor dedicated for thermal experiments. The whole system is implemented in UMC CMOS 0.18 μm (1.8 V) technology.

  20. Y-STR frequency surveying method

    DEFF Research Database (Denmark)

    Willuweit, Sascha; Caliebe, Amke; Andersen, Mikkel Meyer

    2011-01-01

    Reasonable formalized methods to estimate the frequencies of DNA profiles generated from lineage markers have been proposed in the past years and were discussed in the forensic community. Recently, collections of population data on the frequencies of variations in Y chromosomal STR profiles have...... reached a new quality with the establishment of the comprehensive neatly quality-controlled reference database YHRD. Grounded on such unrivalled empirical material from hundreds of populations studies the core assumption of the Haplotype Frequency Surveying Method originally described 10 years ago can...... be tested and improved. Here we provide new approaches to calculate the parameters used in the frequency surveying method: a maximum likelihood estimation of the regression parameters (r1, r2, s1 and s2) and a revised Frequency Surveying framework with variable binning and a database preprocessing to take...

  1. Frequency conversion of structured light.

    Science.gov (United States)

    Steinlechner, Fabian; Hermosa, Nathaniel; Pruneri, Valerio; Torres, Juan P

    2016-02-15

    Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.

  2. Design of Asymmetrical Relay Resonators for Maximum Efficiency of Wireless Power Transfer

    Directory of Open Access Journals (Sweden)

    Bo-Hee Choi

    2016-01-01

    Full Text Available This paper presents a new design method of asymmetrical relay resonators for maximum wireless power transfer. A new design method for relay resonators is demanded because maximum power transfer efficiency (PTE is not obtained at the resonant frequency of unit resonator. The maximum PTE for relay resonators is obtained at the different resonances of unit resonator. The optimum design of asymmetrical relay is conducted by both the optimum placement and the optimum capacitance of resonators. The optimum placement is found by scanning the positions of the relays and optimum capacitance can be found by using genetic algorithm (GA. The PTEs are enhanced when capacitance is optimally designed by GA according to the position of relays, respectively, and then maximum efficiency is obtained at the optimum placement of relays. The capacitance of the second resonator to nth resonator and the load resistance should be determined for maximum efficiency while the capacitance of the first resonator and the source resistance are obtained for the impedance matching. The simulated and measured results are in good agreement.

  3. Stepped-frequency radar sensors theory, analysis and design

    CERN Document Server

    Nguyen, Cam

    2016-01-01

    This book presents the theory, analysis and design of microwave stepped-frequency radar sensors. Stepped-frequency radar sensors are attractive for various sensing applications that require fine resolution. The book consists of five chapters. The first chapter describes the fundamentals of radar sensors including applications followed by a review of ultra-wideband pulsed, frequency-modulated continuous-wave (FMCW), and stepped-frequency radar sensors. The second chapter discusses a general analysis of radar sensors including wave propagation in media and scattering on targets, as well as the radar equation. The third chapter addresses the analysis of stepped-frequency radar sensors including their principles and design parameters. Chapter 4 presents the development of two stepped-frequency radar sensors at microwave and millimeter-wave frequencies based on microwave integrated circuits (MICs), microwave monolithic integrated circuits (MMICs) and printed-circuit antennas, and discusses their signal processing....

  4. Fundamentals of electromagnetics 1 internal behavior of lumped elements

    CERN Document Server

    Voltmer, David

    2007-01-01

    This book is the first of two volumes which have been created to provide an understanding of the basic principles and applications of electromagnetic fields for electrical engineering students. Fundamentals of Electromagnetics Vol 1: Internal Behavior of Lumped Elements focuses upon the DC and low-frequency behavior of electromagnetic fields within lumped elements. The properties of electromagnetic fields provide the basis for predicting the terminal characteristics of resistors, capacitors, and inductors. The properties of magnetic circuits are included as well. For slightly higher frequencie

  5. Harmonic generation with a dual frequency pulse.

    Science.gov (United States)

    Keravnou, Christina P; Averkiou, Michalakis A

    2014-05-01

    Nonlinear imaging was implemented in commercial ultrasound systems over the last 15 years offering major advantages in many clinical applications. In this work, pulsing schemes coupled with a dual frequency pulse are presented. The pulsing schemes considered were pulse inversion, power modulation, and power modulated pulse inversion. The pulse contains a fundamental frequency f and a specified amount of its second harmonic 2f. The advantages and limitations of this method were evaluated with both acoustic measurements of harmonic generation and theoretical simulations based on the KZK equation. The use of two frequencies in a pulse results in the generation of the sum and difference frequency components in addition to the other harmonic components. While with single frequency pulses, only power modulation and power modulated pulse inversion contained odd harmonic components, with the dual frequency pulse, pulse inversion now also contains odd harmonic components.

  6. Spatial Frequency Discrimination : Effects of Age, Reward, and Practice

    OpenAIRE

    van den Boomen, Carlijn; Peters, Judith Carolien

    2017-01-01

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effec...

  7. Slow light in a semiconductor waveguide at gigahertz frequencies

    DEFF Research Database (Denmark)

    Mørk, Jesper; Kjær, Rasmus; Poel, Mike van der

    2005-01-01

    -analytical model based on the effect of coherent population oscillations and taking into account propagation effects is derived and is shown to well account for the experimental results. It is shown that the carrier lifetime limits the maximum achievable delay. Based on the general model we analyze fundamental...

  8. Maximum generation power evaluation of variable frequency offshore wind farms when connected to a single power converter

    Energy Technology Data Exchange (ETDEWEB)

    Gomis-Bellmunt, Oriol; Sumper, Andreas [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2, 08028 Barcelona (Spain); IREC Catalonia Institute for Energy Research, Barcelona (Spain); Junyent-Ferre, Adria; Galceran-Arellano, Samuel [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2, 08028 Barcelona (Spain)

    2010-10-15

    The paper deals with the evaluation of power generated by variable and constant frequency offshore wind farms connected to a single large power converter. A methodology to analyze different wind speed scenarios and system electrical frequencies is presented and applied to a case study, where it is shown that the variable frequency wind farm concept (VF) with a single power converter obtains 92% of the total available power, obtained with individual power converters in each wind turbine (PC). The PC scheme needs multiple power converters implying drawbacks in terms of cost, maintenance and reliability. The VF scheme is also compared to a constant frequency scheme CF, and it is shown that a significant power increase of more than 20% can be obtained with VF. The case study considers a wind farm composed of four wind turbines based on synchronous generators. (author)

  9. Observation of copious emission at the fundamental frequency by a Smith-Purcell free-electron laser with sidewalls

    International Nuclear Information System (INIS)

    Gardelle, J.; Modin, P.; Donohue, J. T.

    2012-01-01

    An experiment at microwave frequencies confirms the recent prediction that a Smith-Purcell [S. J. Smith and E. M. Purcell, Phys. Rev. 92, 1069 (1953)] free-electron laser equipped with sidewalls can emit radiation at the frequency of the surface wave. The power output is considerably greater than for the previously observed emission at the second harmonic, in agreement with three-dimensional simulations. The dependence of frequency on beam energy and emission angle is in good agreement with three-dimensional theory and simulations. Provided that a reduction in scale can be achieved, a path is open to coherent Smith-Purcell radiation at terahertz frequency.

  10. Fundamental and Harmonic Oscillations in Neighboring Coronal Loops

    Science.gov (United States)

    Li, Hongbo; Liu, Yu; Vai Tam, Kuan

    2017-06-01

    We present observations of multimode (fundamental and harmonic) oscillations in a loop system, which appear to be simultaneously excited by a GOES C-class flare. Analysis of the periodic oscillations reveals that (1) the primary loop with a period of P a ≈ 4 minutes and a secondary loop with two periods of P a ≈ 4 minutes and P b ≈ 2 minutes are detected simultaneously in closely spaced loop strands; (2) both oscillation components have their peak amplitudes near the loop apex, while in the second loop the low-frequency component P a dominates in a loop segment that is two times larger than the high-frequency component P b ; (3) the harmonic mode P b shows the largest deviation from a sinusoidal loop shape at the loop apex. We conclude that multiple harmonic modes with different displacement profiles can be excited simultaneously even in closely spaced strands, similar to the overtones of a violin string.

  11. Dynamic phasor based frequency scanning for grid-connected ...

    Indian Academy of Sciences (India)

    M K Das

    2017-10-11

    Oct 11, 2017 ... situations, it is not so for systems with low-order harmonics, individual-phase schemes, unbalanced or single- ..... rents at x А 2xo and x, respectively, due to the fundamental ... c = xot, where xo is the operating frequency.

  12. Conical Double Frequency Emission by Femtosecond Laser Pulses from DKDP

    International Nuclear Information System (INIS)

    Xi-Peng, Zhang; Hong-Bing, Jiang; Shan-Chun, Tang; Qi-Huang, Gong

    2009-01-01

    Conical double frequency emission is investigated by femtosecond laser pulses at a wavelength of 800 nm in a DKDP crystal. It is demonstrated that the sum frequency of incident wave and its scattering wave accounts for the conical double frequency emission. The gaps on the conical rings are observed and they are very sensitive to the propagation direction, and thus could be used to detect the small angle deviation of surface direction. (fundamental areas of phenomenology (including applications))

  13. Low frequency steady-state brain responses modulate large scale functional networks in a frequency-specific means.

    Science.gov (United States)

    Wang, Yi-Feng; Long, Zhiliang; Cui, Qian; Liu, Feng; Jing, Xiu-Juan; Chen, Heng; Guo, Xiao-Nan; Yan, Jin H; Chen, Hua-Fu

    2016-01-01

    Neural oscillations are essential for brain functions. Research has suggested that the frequency of neural oscillations is lower for more integrative and remote communications. In this vein, some resting-state studies have suggested that large scale networks function in the very low frequency range (frequency characteristics of brain networks because both resting-state studies and conventional frequency tagging approaches cannot simultaneously capture multiple large scale networks in controllable cognitive activities. In this preliminary study, we aimed to examine whether large scale networks can be modulated by task-induced low frequency steady-state brain responses (lfSSBRs) in a frequency-specific pattern. In a revised attention network test, the lfSSBRs were evoked in the triple network system and sensory-motor system, indicating that large scale networks can be modulated in a frequency tagging way. Furthermore, the inter- and intranetwork synchronizations as well as coherence were increased at the fundamental frequency and the first harmonic rather than at other frequency bands, indicating a frequency-specific modulation of information communication. However, there was no difference among attention conditions, indicating that lfSSBRs modulate the general attention state much stronger than distinguishing attention conditions. This study provides insights into the advantage and mechanism of lfSSBRs. More importantly, it paves a new way to investigate frequency-specific large scale brain activities. © 2015 Wiley Periodicals, Inc.

  14. Designs of two and three cavity gyroklystron amplifiers operating at fundamental, second, and fourth harmonics

    International Nuclear Information System (INIS)

    Saraph, G.P.; Lawson, W.; Latham, P.E.; Cheng, J.; Castle, M.

    1995-01-01

    Two and three cavity, co-axial, relativistic gyroklystron amplifiers are investigated for driving future linear colliders. Detailed designs of gyroklystrons operating at fundamental (8.568 GHz), second (17.136 GHz), and fourth harmonic (34.272 GHz) frequencies are presented. Numerical simulations predict over 40% efficiency, 45-50 dB gain, and 100-160 MW power level for the fundamental and second harmonic designs. It is shown that introducing a penultimate (buncher) cavity significantly improves efficiency and gain of the second harmonic amplifier. The fourth harmonic design has a modest efficiency of 10-15%

  15. Double-tailored nonimaging reflector optics for maximum-performance solar concentration.

    Science.gov (United States)

    Goldstein, Alex; Gordon, Jeffrey M

    2010-09-01

    A nonimaging strategy that tailors two mirror contours for concentration near the étendue limit is explored, prompted by solar applications where a sizable gap between the optic and absorber is required. Subtle limitations of this simultaneous multiple surface method approach are derived, rooted in the manner in which phase space boundaries can be tailored according to the edge-ray principle. The fundamental categories of double-tailored reflective optics are identified, only a minority of which can pragmatically offer maximum concentration at high collection efficiency. Illustrative examples confirm that acceptance half-angles as large as 30 mrad can be realized at a flux concentration of approximately 1000.

  16. A new algorithm for a high-modulation frequency and high-speed digital lock-in amplifier

    International Nuclear Information System (INIS)

    Jiang, G L; Yang, H; Li, R; Kong, P

    2016-01-01

    To increase the maximum modulation frequency of the digital lock-in amplifier in an online system, we propose a new algorithm using a square wave reference whose frequency is an odd sub-multiple of the modulation frequency, which is based on odd harmonic components in the square wave reference. The sampling frequency is four times the modulation frequency to insure the orthogonality of reference sequences. Only additions and subtractions are used to implement phase-sensitive detection, which speeds up the computation in lock-in. Furthermore, the maximum modulation frequency of a lock-in is enhanced considerably. The feasibility of this new algorithm is tested by simulation and experiments. (paper)

  17. Fundamental rights reflected by the legislation regarding radiation and nuclear power

    International Nuclear Information System (INIS)

    Han, Eun Ok; Lee, Jae Seong; Cho, Hong Jea

    2016-01-01

    Despite the visible growth in radiation usage and nuclear power development, the analysis of their relationship with fundamental rights, a subject of public concern regarding issues including the right to health, environmental rights, safety rights, the right to know, the right to development, and the right to life, is currently non-existent. 15-29By examining various fundamental rights in the context of positive laws regarding radiation and nuclear power in an idealistic perspective that guarantees the maximum degree of rights, this paper aims to propose legislative supplements that will lead to improvements in quality of life. In the South Korean Constitution, radiation and nuclear power is a subject incorporating several rights, including at least 12 clauses that are directly related to fundamental rights; these constitutional rights are manifested in the various clauses of the 14 positive laws regarding radiation and nuclear power. The question on the relative importance of each fundamental right as reflected in these positive laws- whether the right to life should be prioritized or considered equal in weight to the right to health, environmental rights, the right to know, and safety rights- requires careful deliberation and is difficult to humanly resolve in the short term. Making policy that expands the usage of radiation and nuclear power while simultaneously preventing their associated risks is an important task for the Republic of Korea, and a proper value judgment is necessary to find a balance in its associated rights

  18. Fundamental rights reflected by the legislation regarding radiation and nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Han, Eun Ok [Korea Academy of Nuclear Safety, Seoul (Korea, Republic of); Lee, Jae Seong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Cho, Hong Jea [Korea National Defense University, Goyang (Korea, Republic of)

    2016-05-15

    Despite the visible growth in radiation usage and nuclear power development, the analysis of their relationship with fundamental rights, a subject of public concern regarding issues including the right to health, environmental rights, safety rights, the right to know, the right to development, and the right to life, is currently non-existent. 15-29By examining various fundamental rights in the context of positive laws regarding radiation and nuclear power in an idealistic perspective that guarantees the maximum degree of rights, this paper aims to propose legislative supplements that will lead to improvements in quality of life. In the South Korean Constitution, radiation and nuclear power is a subject incorporating several rights, including at least 12 clauses that are directly related to fundamental rights; these constitutional rights are manifested in the various clauses of the 14 positive laws regarding radiation and nuclear power. The question on the relative importance of each fundamental right as reflected in these positive laws- whether the right to life should be prioritized or considered equal in weight to the right to health, environmental rights, the right to know, and safety rights- requires careful deliberation and is difficult to humanly resolve in the short term. Making policy that expands the usage of radiation and nuclear power while simultaneously preventing their associated risks is an important task for the Republic of Korea, and a proper value judgment is necessary to find a balance in its associated rights.

  19. Robust k-mer frequency estimation using gapped k-mers.

    Science.gov (United States)

    Ghandi, Mahmoud; Mohammad-Noori, Morteza; Beer, Michael A

    2014-08-01

    Oligomers of fixed length, k, commonly known as k-mers, are often used as fundamental elements in the description of DNA sequence features of diverse biological function, or as intermediate elements in the constuction of more complex descriptors of sequence features such as position weight matrices. k-mers are very useful as general sequence features because they constitute a complete and unbiased feature set, and do not require parameterization based on incomplete knowledge of biological mechanisms. However, a fundamental limitation in the use of k-mers as sequence features is that as k is increased, larger spatial correlations in DNA sequence elements can be described, but the frequency of observing any specific k-mer becomes very small, and rapidly approaches a sparse matrix of binary counts. Thus any statistical learning approach using k-mers will be susceptible to noisy estimation of k-mer frequencies once k becomes large. Because all molecular DNA interactions have limited spatial extent, gapped k-mers often carry the relevant biological signal. Here we use gapped k-mer counts to more robustly estimate the ungapped k-mer frequencies, by deriving an equation for the minimum norm estimate of k-mer frequencies given an observed set of gapped k-mer frequencies. We demonstrate that this approach provides a more accurate estimate of the k-mer frequencies in real biological sequences using a sample of CTCF binding sites in the human genome.

  20. Frequency dependent characteristics of solar impulsive radio bursts

    International Nuclear Information System (INIS)

    Das, T.K.; Das Gupta, M.K.

    1983-01-01

    An investigation was made of the impulsive radio bursts observed in the frequency range 0.245 to 35 GHz. Important results obtained are: (i) Simple type 1 bursts with intensities 0 to 10 f.u. and simple type 2 bursts with intensities 10 to 500 f.u. are predominant in the frequency ranges 1.415 to 4.995 GHz and 4.995 to 8.8 GHz, respectively; (ii) With maxima around 2.7 GHz and 4 GHz for the first and second types respectively, the durations of the radio bursts decrease gradually both towards lower and higher frequencies; (iii) As regards occurrences, the first type dominates in the southern solar hemisphere peaking around 8.8 GHz, whereas the second type favours the north with no well-defined maximum in any frequency; (iv) Both types prefer the eastern hemisphere, the peak occurrences being around 8.8 GHz and 5 GHz for the two successive types, respectively; (c) The spectra of impulsive radio bursts are generally of the inverted U-type with the maximum emission intensity between 5 and 15 GHz. (author)

  1. 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

  2. Instantaneous and Frequency-Warped Signal Processing Techniques for Auditory Source Separation.

    Science.gov (United States)

    Wang, Avery Li-Chun

    This thesis summarizes several contributions to the areas of signal processing and auditory source separation. The philosophy of Frequency-Warped Signal Processing is introduced as a means for separating the AM and FM contributions to the bandwidth of a complex-valued, frequency-varying sinusoid p (n), transforming it into a signal with slowly-varying parameters. This transformation facilitates the removal of p (n) from an additive mixture while minimizing the amount of damage done to other signal components. The average winding rate of a complex-valued phasor is explored as an estimate of the instantaneous frequency. Theorems are provided showing the robustness of this measure. To implement frequency tracking, a Frequency-Locked Loop algorithm is introduced which uses the complex winding error to update its frequency estimate. The input signal is dynamically demodulated and filtered to extract the envelope. This envelope may then be remodulated to reconstruct the target partial, which may be subtracted from the original signal mixture to yield a new, quickly-adapting form of notch filtering. Enhancements to the basic tracker are made which, under certain conditions, attain the Cramer -Rao bound for the instantaneous frequency estimate. To improve tracking, the novel idea of Harmonic -Locked Loop tracking, using N harmonically constrained trackers, is introduced for tracking signals, such as voices and certain musical instruments. The estimated fundamental frequency is computed from a maximum-likelihood weighting of the N tracking estimates, making it highly robust. The result is that harmonic signals, such as voices, can be isolated from complex mixtures in the presence of other spectrally overlapping signals. Additionally, since phase information is preserved, the resynthesized harmonic signals may be removed from the original mixtures with relatively little damage to the residual signal. Finally, a new methodology is given for designing linear-phase FIR filters

  3. Examination into the maximum rotational frequency for an in-plane switched active waveplate device

    International Nuclear Information System (INIS)

    Davidson, A J; Elston, S J; Raynes, E P

    2005-01-01

    An examination of an active waveplate device using a one-dimensional model, giving numerical and analytical results, is presented. The model calculates the director and twist configuration by minimizing the free energy of the system with simple homeotropic boundary conditions. The effect of varying the in-plane electric field in both magnitude and direction is examined, and it is shown that the twist through the cell is constant in time as the field is rotated. As the electric field is rotated, the director field lags behind by an angle which increases as the frequency of the electric field rotation increases. When this angle reaches approximately π/4 the director field no longer follows the electric field in a uniform way. Using mathematical analysis it is shown that the conditions on which the director profile will fail to follow the rotating electric field depend on the frequency of electric field rotation, the magnitude of the electric field, the dielectric anisotropy and the viscosity of the liquid crystal

  4. Fundamentals of electronics

    CERN Document Server

    Schubert, Thomas F

    2015-01-01

    This book, Electronic Devices and Circuit Application, is the first of four books of a larger work, Fundamentals of Electronics. It is comprised of four chapters describing the basic operation of each of the four fundamental building blocks of modern electronics: operational amplifiers, semiconductor diodes, bipolar junction transistors, and field effect transistors. Attention is focused on the reader obtaining a clear understanding of each of the devices when it is operated in equilibrium. Ideas fundamental to the study of electronic circuits are also developed in the book at a basic level to

  5. Fundamentals of gas dynamics

    CERN Document Server

    Babu, V

    2014-01-01

    Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav

  6. Frequency modulation excursion and rate discrimination in normal-hearing and hearing-impaired listeners

    DEFF Research Database (Denmark)

    Schindwolf, Isabel; Vatti, Marianna; Santurette, Sébastien

    Most natural sounds contain frequency fluctuations over time such as changes in their fundamental frequency, non-periodic speech formant transitions, or periodic fluctuations like musical vibrato. These are sometimes characterized as frequency modulation (FM) with a given excursion (FMe) and rate......, this study investigated the effects of age and SNHL on FMe and FMr difference limens (DLs) for reference values typical of frequency fluctuations observed in speech and music signals....

  7. Periodic rotation noise induced by the crosstalk between two beat-frequency signals in multi-oscillator ring laser gyros

    International Nuclear Information System (INIS)

    Lu, Guangfeng; Wang, Zhiguo; Fan, Zhenfang; Luo, Hui

    2014-01-01

    Periodic rotation noise in the outputs of multi-oscillator ring laser gyros (MRLGs) is investigated in this paper for the first time. It is proved theoretically and experimentally that noise is induced by the crosstalk between two beat-frequency signals, which are combined from the left and right circularly polarized counter-propagating beams in MRLGs. Theoretical analysis and experimental results also indicate that the fundamental frequency of this noise is equal to the frequency difference between the two beat-frequency signals and the amplitude of the fundamental component is proportional to the crosstalk ratio between the two beat-frequency signals. Further, the amplitude of the nth-order component is proportional to the nth power of the crosstalk ratio. (paper)

  8. Bloch–Siegert shift in application to the astrophysical determination of the fundamental constants variation

    International Nuclear Information System (INIS)

    Solovyev, Dmitry

    2013-01-01

    We have evaluated the Bloch–Siegert shift for the different values of magnetic field's strengths defined at astrophysical conditions, i.e. when the stars with the strong surface magnetic fields are taken as a powerful pumping source of radiation. It is found that the additional shift of resonant frequency should be taken into account in the search for the time variation of the fundamental constants. The main conclusion is that the influence of the electromagnetic field should be considered carefully in each special case of the corresponding frequency determination

  9. On the maximum-entropy/autoregressive modeling of time series

    Science.gov (United States)

    Chao, B. F.

    1984-01-01

    The autoregressive (AR) model of a random process is interpreted in the light of the Prony's relation which relates a complex conjugate pair of poles of the AR process in the z-plane (or the z domain) on the one hand, to the complex frequency of one complex harmonic function in the time domain on the other. Thus the AR model of a time series is one that models the time series as a linear combination of complex harmonic functions, which include pure sinusoids and real exponentials as special cases. An AR model is completely determined by its z-domain pole configuration. The maximum-entropy/autogressive (ME/AR) spectrum, defined on the unit circle of the z-plane (or the frequency domain), is nothing but a convenient, but ambiguous visual representation. It is asserted that the position and shape of a spectral peak is determined by the corresponding complex frequency, and the height of the spectral peak contains little information about the complex amplitude of the complex harmonic functions.

  10. THE IMPACT OF FREQUENCY STANDARDS ON COHERENCE IN VLBI AT THE HIGHEST FREQUENCIES

    Energy Technology Data Exchange (ETDEWEB)

    Rioja, M.; Dodson, R. [ICRAR, University of Western Australia, Perth (Australia); Asaki, Y. [Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuou, Sagamihara, Kanagawa 252-5210 (Japan); Hartnett, J. [School of Physics, University of Western Australia, Perth (Australia); Tingay, S., E-mail: maria.rioja@icrar.org [ICRAR, Curtin University, Perth (Australia)

    2012-10-01

    We have carried out full imaging simulation studies to explore the impact of frequency standards in millimeter and submillimeter very long baseline interferometry (VLBI), focusing on the coherence time and sensitivity. In particular, we compare the performance of the H-maser, traditionally used in VLBI, to that of ultra-stable cryocooled sapphire oscillators over a range of observing frequencies, weather conditions, and analysis strategies. Our simulations show that at the highest frequencies, the losses induced by H-maser instabilities are comparable to those from high-quality tropospheric conditions. We find significant benefits in replacing H-masers with cryocooled sapphire oscillator based frequency references in VLBI observations at frequencies above 175 GHz in sites which have the best weather conditions; at 350 GHz we estimate a 20%-40% increase in sensitivity over that obtained when the sites have H-masers, for coherence losses of 20%-10%, respectively. Maximum benefits are to be expected by using co-located Water Vapor Radiometers for atmospheric correction. In this case, we estimate a 60%-120% increase in sensitivity over the H-maser at 350 GHz.

  11. Three essays on the econometric analysis of high frequency financial data

    OpenAIRE

    OOMEN, Roel C. A.

    2003-01-01

    Defence date: 13 June 2003 Examining Board: Prof. H. Peter Boswijk, University of Amsterdam ; Prof. Søren Johansen, University of Copenhagen, Supervisor ; Prof. Helmut Lütkepohl, EUI ; Prof. Stephen Taylor, Lancaster University This thesis is motivated by the observation that the time series properties of financial security prices can vary fundamentally with their sampling frequency. Econometric models developed for low frequency data may thus be unsuitable for high frequency data and v...

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

    Science.gov (United States)

    Bleeker, H J; Lewin, P A

    2000-01-01

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

  13. Flood frequency analysis for nonstationary annual peak records in an urban drainage basin

    Science.gov (United States)

    Villarini, Gabriele; Smith, James A.; Serinaldi, Francesco; Bales, Jerad; Bates, Paul D.; Krajewski, Witold F.

    2009-08-01

    Flood frequency analysis in urban watersheds is complicated by nonstationarities of annual peak records associated with land use change and evolving urban stormwater infrastructure. In this study, a framework for flood frequency analysis is developed based on the Generalized Additive Models for Location, Scale and Shape parameters (GAMLSS), a tool for modeling time series under nonstationary conditions. GAMLSS is applied to annual maximum peak discharge records for Little Sugar Creek, a highly urbanized watershed which drains the urban core of Charlotte, North Carolina. It is shown that GAMLSS is able to describe the variability in the mean and variance of the annual maximum peak discharge by modeling the parameters of the selected parametric distribution as a smooth function of time via cubic splines. Flood frequency analyses for Little Sugar Creek (at a drainage area of 110km) show that the maximum flow with a 0.01-annual probability (corresponding to 100-year flood peak under stationary conditions) over the 83-year record has ranged from a minimum unit discharge of 2.1mskm to a maximum of 5.1mskm. An alternative characterization can be made by examining the estimated return interval of the peak discharge that would have an annual exceedance probability of 0.01 under the assumption of stationarity (3.2mskm). Under nonstationary conditions, alternative definitions of return period should be adapted. Under the GAMLSS model, the return interval of an annual peak discharge of 3.2mskm ranges from a maximum value of more than 5000 years in 1957 to a minimum value of almost 8 years for the present time (2007). The GAMLSS framework is also used to examine the links between population trends and flood frequency, as well as trends in annual maximum rainfall. These analyses are used to examine evolving flood frequency over future decades.

  14. Maximum likelihood window for time delay estimation

    International Nuclear Information System (INIS)

    Lee, Young Sup; Yoon, Dong Jin; Kim, Chi Yup

    2004-01-01

    Time delay estimation for the detection of leak location in underground pipelines is critically important. Because the exact leak location depends upon the precision of the time delay between sensor signals due to leak noise and the speed of elastic waves, the research on the estimation of time delay has been one of the key issues in leak lovating with the time arrival difference method. In this study, an optimal Maximum Likelihood window is considered to obtain a better estimation of the time delay. This method has been proved in experiments, which can provide much clearer and more precise peaks in cross-correlation functions of leak signals. The leak location error has been less than 1 % of the distance between sensors, for example the error was not greater than 3 m for 300 m long underground pipelines. Apart from the experiment, an intensive theoretical analysis in terms of signal processing has been described. The improved leak locating with the suggested method is due to the windowing effect in frequency domain, which offers a weighting in significant frequencies.

  15. Effective line intensity measurements of trans-nitrous acid (HONO) of the ν1 band near 3600 cm-1 using laser difference-frequency spectrometer

    Science.gov (United States)

    Maamary, Rabih; Fertein, Eric; Fourmentin, Marc; Dewaele, Dorothée; Cazier, Fabrice; Chen, Changshui; Chen, Weidong

    2017-07-01

    We report on the measurements of the effective line intensities of the ν1 fundamental band of trans-nitrous acid (trans-HONO) in the infrared near 3600 cm-1 (2.78 μm). A home-made widely tunable laser spectrometer based on difference-frequency generation (DFG) was used for this study. The strengths of 28 well-resolved absorption lines of the ν1 band were determined by scaling their absorption intensities to the well referenced absorption line intensity of the ν3 band of trans-HONO around 1250 cm-1 recorded simultaneously with the help of a DFB quantum cascade laser (QCL) spectrometer. The maximum measurement uncertainty of 12% in the line intensities is mainly determined by the uncertainty announced in the referenced line intensities, while the measurement precision in frequency positions of the absorption lines is better than 6×10-4 cm-1. The cross-measurement carried out in the present work allows one to perform intensity calibration using well referenced line parameters.

  16. Exchange Rates and Fundamentals.

    Science.gov (United States)

    Engel, Charles; West, Kenneth D.

    2005-01-01

    We show analytically that in a rational expectations present-value model, an asset price manifests near-random walk behavior if fundamentals are I (1) and the factor for discounting future fundamentals is near one. We argue that this result helps explain the well-known puzzle that fundamental variables such as relative money supplies, outputs,…

  17. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  18. Radiology fundamentals

    CERN Document Server

    Singh, Harjit

    2011-01-01

    ""Radiology Fundamentals"" is a concise introduction to the dynamic field of radiology for medical students, non-radiology house staff, physician assistants, nurse practitioners, radiology assistants, and other allied health professionals. The goal of the book is to provide readers with general examples and brief discussions of basic radiographic principles and to serve as a curriculum guide, supplementing a radiology education and providing a solid foundation for further learning. Introductory chapters provide readers with the fundamental scientific concepts underlying the medical use of imag

  19. Robust Frequency and Voltage Stability Control Strategy for Standalone AC/DC Hybrid Microgrid

    Directory of Open Access Journals (Sweden)

    Furqan Asghar

    2017-05-01

    Full Text Available The microgrid (MG concept is attracting considerable attention as a solution to energy deficiencies, especially in remote areas, but the intermittent nature of renewable sources and varying loads cause many control problems and thereby affect the quality of power within a microgrid operating in standalone mode. This might cause large frequency and voltage deviations in the system due to unpredictable output power fluctuations. Furthermore, without any main grid support, it is more complex to control and manage the system. In past, droop control and various other coordination control strategies have been presented to stabilize the microgrid frequency and voltages, but in order to utilize the available resources up to their maximum capacity in a positive way, new and robust control mechanisms are required. In this paper, a standalone microgrid is presented, which integrates renewable energy-based distributed generations and local loads. A fuzzy logic-based intelligent control technique is proposed to maintain the frequency and DC (direct current-link voltage stability for sudden changes in load or generation power. Also from a frequency control perspective, a battery energy storage system (BESS is suggested as a replacement for a synchronous generator to stabilize the nominal system frequency as a synchronous generator is unable to operate at its maximum efficiency while being controlled for stabilization purposes. Likewise, a super capacitor (SC and BESS is used to stabilize DC bus voltages even though maximum possible energy is being extracted from renewable generated sources using maximum power point tracking. This newly proposed control method proves to be effective by reducing transient time, minimizing the frequency deviations, maintaining voltages even though maximum power point tracking is working and preventing generators from exceeding their power ratings during disturbances. However, due to the BESS limited capacity, load switching

  20. Fundamental constants and tests of theory in Rydberg states of hydrogenlike ions.

    Science.gov (United States)

    Jentschura, Ulrich D; Mohr, Peter J; Tan, Joseph N; Wundt, Benedikt J

    2008-04-25

    A comparison of precision frequency measurements to quantum electrodynamics (QED) predictions for Rydberg states of hydrogenlike ions can yield information on values of fundamental constants and test theory. With the results of a calculation of a key QED contribution reported here, the uncertainty in the theory of the energy levels is reduced to a level where such a comparison can yield an improved value of the Rydberg constant.

  1. Fundamental Constants and Tests of Theory in Rydberg States of Hydrogenlike Ions

    International Nuclear Information System (INIS)

    Jentschura, Ulrich D.; Mohr, Peter J.; Tan, Joseph N.; Wundt, Benedikt J.

    2008-01-01

    A comparison of precision frequency measurements to quantum electrodynamics (QED) predictions for Rydberg states of hydrogenlike ions can yield information on values of fundamental constants and test theory. With the results of a calculation of a key QED contribution reported here, the uncertainty in the theory of the energy levels is reduced to a level where such a comparison can yield an improved value of the Rydberg constant

  2. Spatial Frequency Discrimination : Effects of Age, Reward, and Practice

    NARCIS (Netherlands)

    van den Boomen, Carlijn; Peters, Judith Carolien

    2017-01-01

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of

  3. Spatial Frequency Discrimination : Effects of Age, Reward, and Practice

    NARCIS (Netherlands)

    van den Boomen, Carlijn; Peters, Judith Carolien

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of

  4. Arguing against fundamentality

    Science.gov (United States)

    McKenzie, Kerry

    This paper aims to open up discussion on the relationship between fundamentality and naturalism, and in particular on the question of whether fundamentality may be denied on naturalistic grounds. A historico-inductive argument for an anti-fundamentalist conclusion, prominent within the contemporary metaphysical literature, is examined; finding it wanting, an alternative 'internal' strategy is proposed. By means of an example from the history of modern physics - namely S-matrix theory - it is demonstrated that (1) this strategy can generate similar (though not identical) anti-fundamentalist conclusions on more defensible naturalistic grounds, and (2) that fundamentality questions can be empirical questions. Some implications and limitations of the proposed approach are discussed.

  5. Effect of misspecification of gene frequency on the two-point LOD score.

    Science.gov (United States)

    Pal, D K; Durner, M; Greenberg, D A

    2001-11-01

    In this study, we used computer simulation of simple and complex models to ask: (1) What is the penalty in evidence for linkage when the assumed gene frequency is far from the true gene frequency? (2) If the assumed model for gene frequency and inheritance are misspecified in the analysis, can this lead to a higher maximum LOD score than that obtained under the true parameters? Linkage data simulated under simple dominant, recessive, dominant and recessive with reduced penetrance, and additive models, were analysed assuming a single locus with both the correct and incorrect dominance model and assuming a range of different gene frequencies. We found that misspecifying the analysis gene frequency led to little penalty in maximum LOD score in all models examined, especially if the assumed gene frequency was lower than the generating one. Analysing linkage data assuming a gene frequency of the order of 0.01 for a dominant gene, and 0.1 for a recessive gene, appears to be a reasonable tactic in the majority of realistic situations because underestimating the gene frequency, even when the true gene frequency is high, leads to little penalty in the LOD score.

  6. Multiresonant Frequency-Locked Loop for Grid Synchronization of Power Converters Under Distorted Grid Conditions

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Luna, Alvaro; Candela, Ignacio

    2011-01-01

    This paper presents a new multiresonant frequency-adaptive synchronization method for grid-connected power converters that allows estimating not only the positive- and negative-sequence components of the power signal at the fundamental frequency but also other sequence components at other harmoni...

  7. Fundamental principles of earthquake resistance calculation to be reflected in the next generation regulations

    OpenAIRE

    Mkrtychev Oleg; Dzhinchvelashvili Guram

    2016-01-01

    The article scrutinizes the pressing issues of regulation in the domain of seismic construction. The existing code of rules SNIP II-7-81* “Construction in seismic areas” provides that earthquake resistance calculation be performed on two levels of impact: basic safety earthquake (BSE) and maximum considered earthquake (MCE). However, the very nature of such calculation cannot be deemed well-founded and contradicts the fundamental standards of foreign countries. The authors of the article have...

  8. Secret data embedding scheme modifying the frequency of ...

    Indian Academy of Sciences (India)

    The main purpose of this presented work is to develop a data embedding method based on a new digital image histogram modification approach. The proposed scheme fundamentally is concerned about the frequency of occurrence of the image brightness values of the cover image for the data embedding procedures.

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

    Science.gov (United States)

    Lawton, T. B.

    1985-01-01

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

  10. Frequency Doubling Broadband Light in Multiple Crystals

    International Nuclear Information System (INIS)

    Alford, William J.; Smith, Arlee V.

    2000-01-01

    The authors compare frequency doubling of broadband light in a single nonlinear crystal with doubling in five crystals with intercrystal temporal walk off compensation, and with doubling in five crystals adjusted for offset phase matching frequencies. Using a plane-wave, dispersive numerical model of frequency doubling they study the bandwidth of the second harmonic and the conversion efficiency as functions of crystal length and fundamental irradiance. For low irradiance the offset phase matching arrangement has lower efficiency than a single crystal of the same total length but gives a broader second harmonic bandwidth. The walk off compensated arrangement gives both higher conversion efficiency and broader bandwidth than a single crystal. At high irradiance, both multicrystal arrangements improve on the single crystal efficiency while maintaining broad bandwidth

  11. Recurrence quantification analysis of extremes of maximum and minimum temperature patterns for different climate scenarios in the Mesochora catchment in Central-Western Greece

    Science.gov (United States)

    Panagoulia, Dionysia; Vlahogianni, Eleni I.

    2018-06-01

    A methodological framework based on nonlinear recurrence analysis is proposed to examine the historical data evolution of extremes of maximum and minimum daily mean areal temperature patterns over time under different climate scenarios. The methodology is based on both historical data and atmospheric General Circulation Model (GCM) produced climate scenarios for the periods 1961-2000 and 2061-2100 which correspond to 1 × CO2 and 2 × CO2 scenarios. Historical data were derived from the actual daily observations coupled with atmospheric circulation patterns (CPs). The dynamics of the temperature was reconstructed in the phase-space from the time series of temperatures. The statistically comparing different temperature patterns were based on some discriminating statistics obtained by the Recurrence Quantification Analysis (RQA). Moreover, the bootstrap method of Schinkel et al. (2009) was adopted to calculate the confidence bounds of RQA parameters based on a structural preserving resampling. The overall methodology was implemented to the mountainous Mesochora catchment in Central-Western Greece. The results reveal substantial similarities between the historical maximum and minimum daily mean areal temperature statistical patterns and their confidence bounds, as well as the maximum and minimum temperature patterns in evolution under the 2 × CO2 scenario. A significant variability and non-stationary behaviour characterizes all climate series analyzed. Fundamental differences are produced from the historical and maximum 1 × CO2 scenarios, the maximum 1 × CO2 and minimum 1 × CO2 scenarios, as well as the confidence bounds for the two CO2 scenarios. The 2 × CO2 scenario reflects the strongest shifts in intensity, duration and frequency in temperature patterns. Such transitions can help the scientists and policy makers to understand the effects of extreme temperature changes on water resources, economic development, and health of ecosystems and hence to proceed to

  12. Fundamental neutron physics

    International Nuclear Information System (INIS)

    Deslattes, R.; Dombeck, T.; Greene, G.; Ramsey, N.; Rauch, H.; Werner, S.

    1984-01-01

    Fundamental physics experiments of merit can be conducted at the proposed intense neutron sources. Areas of interest include: neutron particle properties, neutron wave properties, and fundamental physics utilizing reactor produced γ-rays. Such experiments require intense, full-time utilization of a beam station for periods ranging from several months to a year or more

  13. General phase-frequency shifting in the three-phase inductor-converter bridge

    International Nuclear Information System (INIS)

    Ehsani, M.; Kustom, R.L.; Fuja, R.E.; Barnard, T.J.

    1979-01-01

    A fundamental method of shifting phase frequency in the inductor-converter bridge (ICB) for the purpose of controlling the power in real time is presented. Transient switching sequences needed to implement phase-frequency shifting can be developed by the use of this method and the other five system constraints. Two of the constraints that have been expressed in equation form so far are presented. Finally, an alternative algorithm for computing the frequency shifting transient sequences in real time is suggested

  14. Estimate of annual daily maximum rainfall and intense rain equation for the Formiga municipality, MG, Brazil

    Directory of Open Access Journals (Sweden)

    Giovana Mara Rodrigues Borges

    2016-11-01

    Full Text Available Knowledge of the probabilistic behavior of rainfall is extremely important to the design of drainage systems, dam spillways, and other hydraulic projects. This study therefore examined statistical models to predict annual daily maximum rainfall as well as models of heavy rain for the city of Formiga - MG. To do this, annual maximum daily rainfall data were ranked in decreasing order that best describes the statistical distribution by exceedance probability. Daily rainfall disaggregation methodology was used for the intense rain model studies and adjusted with Intensity-Duration-Frequency (IDF and Exponential models. The study found that the Gumbel model better adhered to the data regarding observed frequency as indicated by the Chi-squared test, and that the exponential model best conforms to the observed data to predict intense rains.

  15. Modelling of word usage frequency dynamics using artificial neural network

    International Nuclear Information System (INIS)

    Maslennikova, Yu S; Bochkarev, V V; Voloskov, D S

    2014-01-01

    In this paper the method for modelling of word usage frequency time series is proposed. An artificial feedforward neural network was used to predict word usage frequencies. The neural network was trained using the maximum likelihood criterion. The Google Books Ngram corpus was used for the analysis. This database provides a large amount of data on frequency of specific word forms for 7 languages. Statistical modelling of word usage frequency time series allows finding optimal fitting and filtering algorithm for subsequent lexicographic analysis and verification of frequency trend models

  16. The Fundamental Solution and Its Role in the Optimal Control of Infinite Dimensional Neutral Systems

    International Nuclear Information System (INIS)

    Liu Kai

    2009-01-01

    In this work, we shall consider standard optimal control problems for a class of neutral functional differential equations in Banach spaces. As the basis of a systematic theory of neutral models, the fundamental solution is constructed and a variation of constants formula of mild solutions is established. We introduce a class of neutral resolvents and show that the Laplace transform of the fundamental solution is its neutral resolvent operator. Necessary conditions in terms of the solutions of neutral adjoint systems are established to deal with the fixed time integral convex cost problem of optimality. Based on optimality conditions, the maximum principle for time varying control domain is presented. Finally, the time optimal control problem to a target set is investigated

  17. Multi-frequency acoustic metasurface for extraordinary reflection and sound focusing

    Directory of Open Access Journals (Sweden)

    Yi-Fan Zhu

    2016-12-01

    Full Text Available We theoretically and numerically present the design of multi-frequency acoustic metasurfaces (MFAMs with simple structure that can work not only at fundamental frequency, but also at their harmonic frequencies, which breaks the single frequency limitation in conventional resonance-based acoustic metasurfaces. The phase matched condition for achromatic manipulation is discussed. We demonstrate achromatic extraordinary reflection and sound focusing at 1700Hz, 3400Hz, and 5100Hz, that is, they have the same reflection direction and the same focusing position. This significant feature may pave the way to new type of acoustic metasurface, and will also extend acoustic metasurface applications to strongly nonlinear source cases.

  18. A combined Raman spectroscopic and theoretical investigation of fundamental vibrational bands of furfuryl alcohol (2-furanmethanol)

    DEFF Research Database (Denmark)

    Barsberg, S.; Berg, Rolf W.

    2006-01-01

    . study of FA in weakly interacting environments. It is the first study of FA vibrational properties based on d. functional theory (DFT/B3LYP), and a recently proposed hybrid approach to the calcn. of fundamental frequencies, which also includes an anharmonic contribution. FA occupies five different...

  19. System frequency support of permanent magnet synchronous generator-based wind power plant

    Science.gov (United States)

    Wu, Ziping

    With ever-increasing penetration of wind power into modern electric grids all over the world, a trending replacement of conventional synchronous generators by large wind power plants will likely result in the poor overall frequency regulation performance. On the other hand, permanent magnet synchronous generator wind Turbine System (PMSG-WTG) with full power back to back converters tends to become one of the most promising wind turbine technologies thanks to various advantages. It possesses a significant amount of kinetic energy stored in the rotating mass of turbine blades, which can be utilized to enhance the total inertia of power system. Additionally, the deloaded operation and decoupled control of active and reactive power make it possible for PMSG-WTG to provide a fast frequency regulation through full-power converter. First of all, a comprehensive and in-depth survey is conducted to analyze the motivations for incorporating the inertial response and frequency regulation of VSWT into the system frequency regulation. Besides, control classifications, fundamental control concepts and advanced control schemes implemented for auxiliary frequency support of individual WT or wind power plant are elaborated along with a comparison of the potential frequency regulation capabilities of four major types of WTs. Secondly, a Controls Advanced Research Turbine2-Permanent Magnet Synchronous Generator wind turbine (CART2-PMSG) integrated model representing the typical configuration and operation characteristics of PMSG-WT is established in Matlab/Simulink,. Meanwhile, two different rotor-side converter control schemes, including rotor speed-based control and active power-based control, are integrated into this CART2-PMSG integrated model to perform Maximum Power Point Tracking (MPPT) operation over a wide range of wind speeds, respectively. Thirdly, a novel comprehensive frequency regulation (CFR) control scheme is developed and implemented into the CART2-PMSG model based

  20. Signature of a possible relationship between the maximum CME speed index and the critical frequencies of the F1 and F2 ionospheric layers: Data analysis for a mid-latitude ionospheric station during the solar cycles 23 and 24

    Science.gov (United States)

    Kilcik, Ali; Ozguc, Atila; Yiǧit, Erdal; Yurchyshyn, Vasyl; Donmez, Burcin

    2018-06-01

    We analyze temporal variations of two solar indices, the monthly mean Maximum CME Speed Index (MCMESI) and the International Sunspot Number (ISSN) as well as the monthly median ionospheric critical frequencies (foF1, and foF2) for the time period of 1996-2013, which covers the entire solar cycle 23 and the ascending branch of the cycle 24. We found that the maximum of foF1 and foF2 occurred respectively during the first and second maximum of the ISSN solar activity index in the solar cycle 23. We compared these data sets by using the cross-correlation and hysteresis analysis and found that both foF1 and foF2 show higher correlation with ISSN than the MCMESI during the investigated time period, but when significance levels are considered correlation coefficients between the same indices become comparable. Cross-correlation analysis showed that the agreement between these data sets (solar indices and ionospheric critical frequencies) is better pronounced during the ascending phases of solar cycles, while they display significant deviations during the descending phase. We conclude that there exists a signature of a possible relationship between MCMESI and foF1 and foF2, which means that MCMESI could be used as a possible indicator of solar and geomagnetic activity, even though other investigations are needed.

  1. Hyperbolic equations and frequency interactions

    CERN Document Server

    Caffarelli, Luis

    1998-01-01

    The research topic for this IAS/PCMI Summer Session was nonlinear wave phenomena. Mathematicians from the more theoretical areas of PDEs were brought together with those involved in applications. The goal was to share ideas, knowledge, and perspectives. How waves, or "frequencies", interact in nonlinear phenomena has been a central issue in many of the recent developments in pure and applied analysis. It is believed that wavelet theory-with its simultaneous localization in both physical and frequency space and its lacunarity-is and will be a fundamental new tool in the treatment of the phenomena. Included in this volume are write-ups of the "general methods and tools" courses held by Jeff Rauch and Ingrid Daubechies. Rauch's article discusses geometric optics as an asymptotic limit of high-frequency phenomena. He shows how nonlinear effects are reflected in the asymptotic theory. In the article "Harmonic Analysis, Wavelets and Applications" by Daubechies and Gilbert the main structure of the wavelet theory is...

  2. Islamic fundamentalism in Indonesia

    OpenAIRE

    Nagy, Sandra L.

    1996-01-01

    This is a study of Islamic fundamentalism in Indonesia. Islamic fundamentalism is defined as the return to the foundations and principles of Islam including all movements based on the desire to create a more Islamic society. After describing the practices and beliefs of Islam, this thesis examines the three aspects of universal Islamic fundamentalism: revivalism, resurgence, and radicalism. It analyzes the role of Islam in Indonesia under Dutch colonial rule, an alien Christian imperialist po...

  3. Reliability of mechanisms with periodic random modal frequencies using an extreme value-based approach

    International Nuclear Information System (INIS)

    Savage, Gordon J.; Zhang, Xufang; Son, Young Kap; Pandey, Mahesh D.

    2016-01-01

    Resonance in a dynamic system is to be avoided since it often leads to impaired performance, overstressing, fatigue fracture and adverse human reactions. Thus, it is necessary to know the modal frequencies and ensure they do not coincide with any applied periodic loadings. For a rotating planar mechanism, the coefficients in the mass and stiffness matrices are periodically varying, and if the underlying geometry and material properties are treated as random variables then the modal frequencies are both position-dependent and probabilistic. The avoidance of resonance is now a complex problem. Herein, free vibration analysis helps determine ranges of modal frequencies that in turn, identify the running speeds of the mechanism to be avoided. This paper presents an efficient and accurate sample-based approach to determine probabilistic minimum and maximum extremes of the fundamental frequencies and the angular positions of their occurrence. Then, given critical lower and upper frequency constraints it is straightforward to determine reliability in terms of probability of exceedance. The novelty of the proposed approach is that the original expensive and implicit mechanistic model is replaced by an explicit meta-model that captures the tolerances of the design variables over the entire range of angular positions: position-dependent eigenvalues can be found easily and quickly. Extreme-value statistics of the modal frequencies and extreme-value statistics of the angular positions are readily computed through MCS. Limit-state surfaces that connect the frequencies to the design variables may be easily constructed. Error analysis identifies three errors and the paper presents ways to control them so the methodology can be sufficiently accurate. A numerical example of a flexible four-bar linkage shows the proposed methodology has engineering applications. The impact of the proposed methodology is two-fold: it presents a safe-side analysis based on free vibration methods to

  4. First international workshop on fundamental aspects of post-dryout heat transfer: proceedings

    International Nuclear Information System (INIS)

    Lee, R.

    1984-12-01

    The purpose of the First International Workshop on Fundamental Aspects of Post-Dryout Heat Transfer was to review recent developments and the state of art in the field of post-dryout heat transfer. The workshop centered on interchanging ideas, reviewing current research results, and defining future research needs. The following five sessions dealing with the fundamental aspects of post-dryout heat transfer were held. A Computer Code Modeling and Flow Phenomena session was held dealing with flow rgimes, drop size, drop formation and behavior, interfacial area, interfacial drag, and computer modeling. A Quenching Phenomena session was held dealing with nature of rewetting, maximum wetting temperature, Leidenfrost phenomenon and heat transfer in the vicinity of quench front. A Low-Void Heat Transfer session was held dealing with inverted annular-flow heat transfer, inverted slug-flow heat transfer thermal non-equilibrium and computer modeling. A Dispersed-Flow Heat Transfer session was held dealing with drop interfacial heat transfer, vapor convection, thermal non-equilibrium and correlations and models

  5. Long distance measurement with a femtosecond laser based frequency comb

    Science.gov (United States)

    Bhattacharya, N.; Cui, M.; Zeitouny, M. G.; Urbach, H. P.; van den Berg, S. A.

    2017-11-01

    Recent advances in the field of ultra-short pulse lasers have led to the development of reliable sources of carrier envelope phase stabilized femtosecond pulses. The pulse train generated by such a source has a frequency spectrum that consists of discrete, regularly spaced lines known as a frequency comb. In this case both the frequency repetition and the carrier-envelope-offset frequency are referenced to a frequency standard, like an atomic clock. As a result the accuracy of the frequency standard is transferred to the optical domain, with the frequency comb as transfer oscillator. These unique properties allow the frequency comb to be applied as a versatile tool, not only for time and frequency metrology, but also in fundamental physics, high-precision spectroscopy, and laser noise characterization. The pulse-to-pulse phase relationship of the light emitted by the frequency comb has opened up new directions for long range highly accurate distance measurement.

  6. A Maximum Likelihood Estimation of Vocal-Tract-Related Filter Characteristics for Single Channel Speech Separation

    Directory of Open Access Journals (Sweden)

    Dansereau Richard M

    2007-01-01

    Full Text Available We present a new technique for separating two speech signals from a single recording. The proposed method bridges the gap between underdetermined blind source separation techniques and those techniques that model the human auditory system, that is, computational auditory scene analysis (CASA. For this purpose, we decompose the speech signal into the excitation signal and the vocal-tract-related filter and then estimate the components from the mixed speech using a hybrid model. We first express the probability density function (PDF of the mixed speech's log spectral vectors in terms of the PDFs of the underlying speech signal's vocal-tract-related filters. Then, the mean vectors of PDFs of the vocal-tract-related filters are obtained using a maximum likelihood estimator given the mixed signal. Finally, the estimated vocal-tract-related filters along with the extracted fundamental frequencies are used to reconstruct estimates of the individual speech signals. The proposed technique effectively adds vocal-tract-related filter characteristics as a new cue to CASA models using a new grouping technique based on an underdetermined blind source separation. We compare our model with both an underdetermined blind source separation and a CASA method. The experimental results show that our model outperforms both techniques in terms of SNR improvement and the percentage of crosstalk suppression.

  7. A Maximum Likelihood Estimation of Vocal-Tract-Related Filter Characteristics for Single Channel Speech Separation

    Directory of Open Access Journals (Sweden)

    Mohammad H. Radfar

    2006-11-01

    Full Text Available We present a new technique for separating two speech signals from a single recording. The proposed method bridges the gap between underdetermined blind source separation techniques and those techniques that model the human auditory system, that is, computational auditory scene analysis (CASA. For this purpose, we decompose the speech signal into the excitation signal and the vocal-tract-related filter and then estimate the components from the mixed speech using a hybrid model. We first express the probability density function (PDF of the mixed speech's log spectral vectors in terms of the PDFs of the underlying speech signal's vocal-tract-related filters. Then, the mean vectors of PDFs of the vocal-tract-related filters are obtained using a maximum likelihood estimator given the mixed signal. Finally, the estimated vocal-tract-related filters along with the extracted fundamental frequencies are used to reconstruct estimates of the individual speech signals. The proposed technique effectively adds vocal-tract-related filter characteristics as a new cue to CASA models using a new grouping technique based on an underdetermined blind source separation. We compare our model with both an underdetermined blind source separation and a CASA method. The experimental results show that our model outperforms both techniques in terms of SNR improvement and the percentage of crosstalk suppression.

  8. Active Faraday optical frequency standard.

    Science.gov (United States)

    Zhuang, Wei; Chen, Jingbiao

    2014-11-01

    We propose the mechanism of an active Faraday optical clock, and experimentally demonstrate an active Faraday optical frequency standard based on narrow bandwidth Faraday atomic filter by the method of velocity-selective optical pumping of cesium vapor. The center frequency of the active Faraday optical frequency standard is determined by the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line. The optical heterodyne beat between two similar independent setups shows that the frequency linewidth reaches 281(23) Hz, which is 1.9×10(4) times smaller than the natural linewidth of the cesium 852-nm transition line. The maximum emitted light power reaches 75 μW. The active Faraday optical frequency standard reported here has advantages of narrow linewidth and reduced cavity pulling, which can readily be extended to other atomic transition lines of alkali and alkaline-earth metal atoms trapped in optical lattices at magic wavelengths, making it useful for new generation of optical atomic clocks.

  9. Radio frequency system of the RIKEN ring cyclotron

    International Nuclear Information System (INIS)

    Fujisawa, T.; Ogiwara, K.; Kohara, S.; Oikawa, Y.; Yokoyama, I.; Nagase, M.; Takeshita, I.; Chiba, Y.; Kumata, Y.

    1987-01-01

    The radio-frequency(RF) system of the RIKEN ring cyclotron(K = 540) is required to work in a frequency range of 20 to 45 MHz and to generate the maximum acceleration voltage 250 kV. A new movable box type variable frequency resonator was designed for that purpose. The final amplifier is capable to deliver 300 kW. The resonators and the amplifiers have been installed at RIKEN and the performances are studied. The result shows the movable box type resonator and the power amplifier system satisfy the design aim. (author)

  10. Flood frequency analysis for nonstationary annual peak records in an urban drainage basin

    Science.gov (United States)

    Villarini, G.; Smith, J.A.; Serinaldi, F.; Bales, J.; Bates, P.D.; Krajewski, W.F.

    2009-01-01

    Flood frequency analysis in urban watersheds is complicated by nonstationarities of annual peak records associated with land use change and evolving urban stormwater infrastructure. In this study, a framework for flood frequency analysis is developed based on the Generalized Additive Models for Location, Scale and Shape parameters (GAMLSS), a tool for modeling time series under nonstationary conditions. GAMLSS is applied to annual maximum peak discharge records for Little Sugar Creek, a highly urbanized watershed which drains the urban core of Charlotte, North Carolina. It is shown that GAMLSS is able to describe the variability in the mean and variance of the annual maximum peak discharge by modeling the parameters of the selected parametric distribution as a smooth function of time via cubic splines. Flood frequency analyses for Little Sugar Creek (at a drainage area of 110 km2) show that the maximum flow with a 0.01-annual probability (corresponding to 100-year flood peak under stationary conditions) over the 83-year record has ranged from a minimum unit discharge of 2.1 m3 s- 1 km- 2 to a maximum of 5.1 m3 s- 1 km- 2. An alternative characterization can be made by examining the estimated return interval of the peak discharge that would have an annual exceedance probability of 0.01 under the assumption of stationarity (3.2 m3 s- 1 km- 2). Under nonstationary conditions, alternative definitions of return period should be adapted. Under the GAMLSS model, the return interval of an annual peak discharge of 3.2 m3 s- 1 km- 2 ranges from a maximum value of more than 5000 years in 1957 to a minimum value of almost 8 years for the present time (2007). The GAMLSS framework is also used to examine the links between population trends and flood frequency, as well as trends in annual maximum rainfall. These analyses are used to examine evolving flood frequency over future decades. ?? 2009 Elsevier Ltd.

  11. Iodine frequency references for space

    International Nuclear Information System (INIS)

    Schuldt, Thilo; Braxmaier, Claus; Döringshoff, Klaus; Peters, Achim; Oswald, Markus; Johann, Ulrich

    2017-01-01

    Optical frequency references are a key element for the realization of future space missions. They are needed for missions related to tests of fundamental physics, gravitational wave detection, Earth observation and navigation and ranging. In missions such as GRACE follow-on or LISA the optical frequency reference is used as light source for high-sensitivity inter-satellite distance metrology. While cavity-based systems are current baseline e.g. for LISA, frequency stabilization on a hyperfine transition in molecular iodine near 532 nm is a promising alternative. Due to its absolute frequency, iodine standards crucially simplify the initial spacecraft acquisition procedures. Current setups fulfill the GRACE-FO and LISA frequency stability requirements and are realized near Engineering Model level. We present the current status of our developments on Elegant Breadboard (EBB) and Engineering Model (EM) level taking into account specific design criteria for space compatibility such as compactness (size iodine spectroscopy EM: 38 × 18 × 10 cm 3 ) and robustness. Both setups achieved similar frequency stabilities of ∼ 1 · 10 −14 at an integration time of 1 s and below 5 · 10 −15 at integration times between 10 s and 1000 s. Furthermore, we present an even more compact design currently developed for a sounding rocket mission with launch in 2017. (paper)

  12. Frequency-difference-dependent stochastic resonance in neural systems

    Science.gov (United States)

    Guo, Daqing; Perc, Matjaž; Zhang, Yangsong; Xu, Peng; Yao, Dezhong

    2017-08-01

    Biological neurons receive multiple noisy oscillatory signals, and their dynamical response to the superposition of these signals is of fundamental importance for information processing in the brain. Here we study the response of neural systems to the weak envelope modulation signal, which is superimposed by two periodic signals with different frequencies. We show that stochastic resonance occurs at the beat frequency in neural systems at the single-neuron as well as the population level. The performance of this frequency-difference-dependent stochastic resonance is influenced by both the beat frequency and the two forcing frequencies. Compared to a single neuron, a population of neurons is more efficient in detecting the information carried by the weak envelope modulation signal at the beat frequency. Furthermore, an appropriate fine-tuning of the excitation-inhibition balance can further optimize the response of a neural ensemble to the superimposed signal. Our results thus introduce and provide insights into the generation and modulation mechanism of the frequency-difference-dependent stochastic resonance in neural systems.

  13. Probable Maximum Earthquake Magnitudes for the Cascadia Subduction

    Science.gov (United States)

    Rong, Y.; Jackson, D. D.; Magistrale, H.; Goldfinger, C.

    2013-12-01

    The concept of maximum earthquake magnitude (mx) is widely used in seismic hazard and risk analysis. However, absolute mx lacks a precise definition and cannot be determined from a finite earthquake history. The surprising magnitudes of the 2004 Sumatra and the 2011 Tohoku earthquakes showed that most methods for estimating mx underestimate the true maximum if it exists. Thus, we introduced the alternate concept of mp(T), probable maximum magnitude within a time interval T. The mp(T) can be solved using theoretical magnitude-frequency distributions such as Tapered Gutenberg-Richter (TGR) distribution. The two TGR parameters, β-value (which equals 2/3 b-value in the GR distribution) and corner magnitude (mc), can be obtained by applying maximum likelihood method to earthquake catalogs with additional constraint from tectonic moment rate. Here, we integrate the paleoseismic data in the Cascadia subduction zone to estimate mp. The Cascadia subduction zone has been seismically quiescent since at least 1900. Fortunately, turbidite studies have unearthed a 10,000 year record of great earthquakes along the subduction zone. We thoroughly investigate the earthquake magnitude-frequency distribution of the region by combining instrumental and paleoseismic data, and using the tectonic moment rate information. To use the paleoseismic data, we first estimate event magnitudes, which we achieve by using the time interval between events, rupture extent of the events, and turbidite thickness. We estimate three sets of TGR parameters: for the first two sets, we consider a geographically large Cascadia region that includes the subduction zone, and the Explorer, Juan de Fuca, and Gorda plates; for the third set, we consider a narrow geographic region straddling the subduction zone. In the first set, the β-value is derived using the GCMT catalog. In the second and third sets, the β-value is derived using both the GCMT and paleoseismic data. Next, we calculate the corresponding mc

  14. Specificity of the Human Frequency Following Response for Carrier and Modulation Frequency Assessed Using Adaptation.

    Science.gov (United States)

    Gockel, Hedwig E; Krugliak, Alexandra; Plack, Christopher J; Carlyon, Robert P

    2015-12-01

    The frequency following response (FFR) is a scalp-recorded measure of phase-locked brainstem activity to stimulus-related periodicities. Three experiments investigated the specificity of the FFR for carrier and modulation frequency using adaptation. FFR waveforms evoked by alternating-polarity stimuli were averaged for each polarity and added, to enhance envelope, or subtracted, to enhance temporal fine structure information. The first experiment investigated peristimulus adaptation of the FFR for pure and complex tones as a function of stimulus frequency and fundamental frequency (F0). It showed more adaptation of the FFR in response to sounds with higher frequencies or F0s than to sounds with lower frequency or F0s. The second experiment investigated tuning to modulation rate in the FFR. The FFR to a complex tone with a modulation rate of 213 Hz was not reduced more by an adaptor that had the same modulation rate than by an adaptor with a different modulation rate (90 or 504 Hz), thus providing no evidence that the FFR originates mainly from neurons that respond selectively to the modulation rate of the stimulus. The third experiment investigated tuning to audio frequency in the FFR using pure tones. An adaptor that had the same frequency as the target (213 or 504 Hz) did not generally reduce the FFR to the target more than an adaptor that differed in frequency (by 1.24 octaves). Thus, there was no evidence that the FFR originated mainly from neurons tuned to the frequency of the target. Instead, the results are consistent with the suggestion that the FFR for low-frequency pure tones at medium to high levels mainly originates from neurons tuned to higher frequencies. Implications for the use and interpretation of the FFR are discussed.

  15. Fundamentals of ergonomic exoskeleton robots

    NARCIS (Netherlands)

    Schiele, A.

    2008-01-01

    This thesis is the first to provide the fundamentals of ergonomic exoskeleton design. The fundamental theory as well as technology necessary to analyze and develop ergonomic wearable robots interacting with humans is established and validated by experiments and prototypes. The fundamentals are (1) a

  16. Lower bounds on the periodic Hamming correlations of frequency hopping sequences with low hit zone

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, several periodic Hamming correlation lower bounds for frequency hopping sequences with low hit zone, with respect to the size p of the frequency slot set, the sequence length L, the family size M, low hit zone LH ( or no hit zone NH ), the maximum periodic Hamming autocorrelation sidelobe Ha and the maximum periodic Hamming crosscorrelation Hc, are established. It is shown that the new bounds include the known Lempel-Greenberger bounds, T.S. Seay bounds and Peng-Fan bounds for the conventional frequency hopping sequences as special cases.

  17. Maximum wind energy extraction strategies using power electronic converters

    Science.gov (United States)

    Wang, Quincy Qing

    2003-10-01

    This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

  18. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  19. Frequency Characteristics of Double-Walled Carbon Nanotube Resonator with Different Length

    Directory of Open Access Journals (Sweden)

    Jun-Ha LEE

    2016-05-01

    Full Text Available In this paper, we have conducted classical molecular dynamics simulations for DWCNTs of various wall lengths to investigate their use as ultrahigh frequency nano-mechanical resonators. We sought to determine the variations in the frequency of these resonators according to changes in the DWCNT wall lengths. For a double-walled carbon nanotube resonator with a shorter inner nanotube, the shorter inner nanotube can be considered to be a flexible core, and thus, the length influences the fundamental frequency. In this paper, we analyze the variation in frequency of ultra-high frequency nano-mechnical resonators constructed from DWCNTs with different wall lengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12951

  20. Frequency chirpings in Alfven continuum

    Science.gov (United States)

    Wang, Ge; Berk, Herb; Breizman, Boris; Zheng, Linjin

    2017-10-01

    We have used a self-consistent mapping technique to describe both the nonlinear wave-energetic particle resonant interaction and its spatial mode structure that depends upon the resonant energetic particle pressure. At the threshold for the onset of the energetic particle mode (EPM), strong chirping emerges in the lower continuum close to the TAE gap and then, driven by strong continuum damping, chirps rapidly to lower frequencies in the Alfven continuum. An adiabatic theory was developed that accurately replicated the results from the simulation where the nonlinearity was only due to the EPM resonant particles. The results show that the EPM-trapped particles have their action conserved during the time of rapid chirping. This adiabaticity enabled wave trapped particles to be confined within their separatrix, and produce even larger resonant structures, that can produce a large amplitude mode far from linearly predicted frequencies. In the present work we describe the effect of additional MHD nonlinearity to this calculation. We studied how the zonal flow component and its nonlinear feedback to the fundamental frequency and found that the MHD nonlinearity doesn't significantly alter the frequency chirping response that is predicted by the calculation that neglects the MHD nonlinearity.

  1. Resonant magnetic pumping at very low frequency

    International Nuclear Information System (INIS)

    Canobbio, Ernesto

    1978-01-01

    We propose to exploit for plasma heating purposes the very low frequency limit of the Alfven wave resonance condition, which reduces essentially to safety factor q=m/n, a rational number. It is shown that a substantial fraction of the total RF-energy can be absorbed by the plasma. The lowest possible frequency value is determined by the maximum tolerable width of the RF-magnetic islands which develop near the singular surface. The obvious interest of the proposed scheme is the low frequency value (f<=10 KHz) which allows the RF-coils to be protected by stainless steel or even to be put outside the liner

  2. CORRELATIONS OF DISK AND JET EMISSION DEVIATING FROM THE FUNDAMENTAL PLANE

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Da-Bin; Mu, Hui-Jun; Lu, Zu-Jia; Liang, En-Wei [GXU-NAOC Center for Astrophysics and Space Sciences, Department of Physics, Guangxi University, Nanning 530004 (China); Gu, Wei-Min; Ma, Ren-Yi, E-mail: lindabin@gxu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

    2015-07-01

    The variability of the accretion rate, which is believed to induce the aperiodic variability of X-ray emission from disks, may affect the energy injection into a jet. In this spirit, a correlation between disk emission and jet emission can be formed even if the mean luminosity of disk emission remains constant. In this work, these correlations are found in the situation in which the luminosity of disk emission is variable and kept at a constant mean value. The obtained correlations may be shallower than that of the fundamental plane of black hole activity. In addition, the slope of correlation may increase with increasing observed frequency of jet emission. For the luminosities spaced over three days, the slope of correlation decreases with increasing black hole mass. The deviation of our found correlations from that of the fundamental plane is related to the suppression of variability in the jet emission in comparison with that in the disk emission. This mechanism may work in some sources in which shallower correlations have been reported. Moreover, it implies that luminosities used to estimate the relation of the fundamental plane should cover an appropriate timescale, in which the variability of jet emission is not significantly suppressed.

  3. Semitone frequency mapping to improve music representation for nucleus cochlear implants

    Directory of Open Access Journals (Sweden)

    Omran Sherif

    2011-01-01

    Full Text Available Abstract The frequency-to-channel mapping for Cochlear implant (CI signal processors was originally designed to optimize speech perception and generally does not preserve the harmonic structure of music sounds. An algorithm aimed at restoring the harmonic relationship of frequency components based on semitone mapping is presented in this article. Two semitone (Smt based mappings in different frequency ranges were investigated. The first, Smt-LF, covers a range from 130 to 1502 Hz which encompasses the fundamental frequency of most musical instruments. The second, Smt-MF, covers a range from 440 to 5040 Hz, allocating frequency bands of sounds close to their characteristic tonotopical sites according to Greenwood's function. Smt-LF, in contrast, transposes the input frequencies onto locations with higher characteristic frequencies. A sequence of 36 synthetic complex tones (C3 to B5, each consisting of a fundamental and 4 harmonic overtones, was processed using the standard (Std, Smt-LF and Smt-MF mappings. The analysis of output signals showed that the harmonic structure between overtones of all complex tones was preserved using Smt mapping. Semitone mapping preserves the harmonic structure and may in turn improve music representation for Nucleus cochlear implants. The proposed semitone mappings incorporate the use of virtual channels to allow frequencies spanning three and a half octaves to be mapped to 43 stimulation channels. A pitch difference limen test was done with normal hearing subjects discriminating pairs of pure tones with different semitone intervals which were processed by a vocoder type simulator of CI sound processing. The results showed better performance with wider semitone intervals. However, no significant difference was found between 22 and 43 channels maps.

  4. Testing Our Fundamental Assumptions

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    fundamental assumptions.A recent focus set in the Astrophysical Journal Letters, titled Focus on Exploring Fundamental Physics with Extragalactic Transients, consists of multiple published studies doing just that.Testing General RelativitySeveral of the articles focus on the 4th point above. By assuming that the delay in photon arrival times is only due to the gravitational potential of the Milky Way, these studies set constraints on the deviation of our galaxys gravitational potential from what GR would predict. The study by He Gao et al. uses the different photon arrival times from gamma-ray bursts to set constraints at eVGeV energies, and the study by Jun-Jie Wei et al. complements this by setting constraints at keV-TeV energies using photons from high-energy blazar emission.Photons or neutrinos from different extragalactic transients each set different upper limits on delta gamma, the post-Newtonian parameter, vs. particle energy or frequency. This is a test of Einsteins equivalence principle: if the principle is correct, delta gamma would be exactly zero, meaning that photons of different energies move at the same velocity through a vacuum. [Tingay Kaplan 2016]S.J. Tingay D.L. Kaplan make the case that measuring the time delay of photons from fast radio bursts (FRBs; transient radio pulses that last only a few milliseconds) will provide even tighter constraints if we are able to accurately determine distances to these FRBs.And Adi Musser argues that the large-scale structure of the universe plays an even greater role than the Milky Way gravitational potential, allowing for even stricter testing of Einsteins equivalence principle.The ever-narrower constraints from these studies all support GR as a correct set of rules through which to interpret our universe.Other Tests of Fundamental PhysicsIn addition to the above tests, Xue-Feng Wu et al. show that FRBs can be used to provide severe constraints on the rest mass of the photon, and S. Croft et al. even touches on what we

  5. Optical frequency divider with division uncertainty at the 10-21 level

    Institute of Scientific and Technical Information of China (English)

    Yuan Yao; Yanyi Jiang; Hongfu Yu; Zhiyi Bi; Longsheng Ma

    2016-01-01

    Optical clocks with unprecedented accuracy of 10-18 promise innovations in many research areas.heir applications rely to a large extent on the ability of precisely converting the frequency from one optical clock to another,or particularly to the frequencies in the iber telecom band for long-distance transmission.his report demonstrates a low-noise,high-precision optical frequency divider,which realizes accurate optical frequency conversion and enables precise measurement of optical frequency ratios.By measuring against the frequency ratio between the fundamental and the second harmonic of a 1064-nm laser instead of a second copy of the same system,we demonstrate that the optical frequency divider has a fractional frequency division instability of 6×10-19 at 1 s and a fractional frequency division uncertainty of 1.4×10-21.he remarkable numbers can support frequency division of the best optical clocks in the world without frequency-conversion-caused degradation of their performance.

  6. Accurate frequency measurements on gyrotrons using a ''gyro-radiometer''

    International Nuclear Information System (INIS)

    Rebuffi, L.

    1986-08-01

    Using an heterodyne system, called ''Gyro-radiometer'', accurated frequency measurements have been carried out on VARIAN 60 GHz gyrotrons. Changing the principal tuning parameters of a gyrotron, we have detected frequency variations up to 100 MHz, ∼ 40 MHz frequency jumps and smaller jumps (∼ 10 MHz) when mismatches in the transmission line were present. FWHM bandwidth of 300 KHz, parasitic frequencies and frequency drift during 100 msec pulses have also been observed. An efficient method to find a stable-, high power-, long pulse-working point of a gyrotron loaded by a transmission line, has been derived. In general, for any power value it is possible to find stable working conditions tuning the principal parameters of the tube in correspondance of a maximum of the emitted frequency

  7. Ultra high frequency induction welding of powder metal compacts

    Energy Technology Data Exchange (ETDEWEB)

    Cavdar, U.; Gulsahin, I.

    2014-10-01

    The application of the iron based Powder Metal (PM) compacts in Ultra High Frequency Induction Welding (UHFIW) were reviewed. These PM compacts are used to produce cogs. This study investigates the methods of joining PM materials enforceability with UHFIW in the industry application. Maximum stress and maximum strain of welded PM compacts were determined by three point bending and strength tests. Microhardness and microstructure of induction welded compacts were determined. (Author)

  8. Ultra high frequency induction welding of powder metal compacts

    International Nuclear Information System (INIS)

    Cavdar, U.; Gulsahin, I.

    2014-01-01

    The application of the iron based Powder Metal (PM) compacts in Ultra High Frequency Induction Welding (UHFIW) were reviewed. These PM compacts are used to produce cogs. This study investigates the methods of joining PM materials enforceability with UHFIW in the industry application. Maximum stress and maximum strain of welded PM compacts were determined by three point bending and strength tests. Microhardness and microstructure of induction welded compacts were determined. (Author)

  9. A theory of the coherent fundamental plasma emission in Tokamaks

    International Nuclear Information System (INIS)

    Alves, M.V.; Chian, A.C.-L.

    1987-01-01

    A theoretical model of coherent radiation near the fundamental plasma frequency in tokamaks is proposed. It is shown that, in the presence of runaway electrons, the beam-generated Langmuir waves (L) can be parametrically converted into electromagnetic waves (T) through ponderomotive coupling to ion acoustic waves (S). Two types of pumps are considered: travelling wave pump and standing wave pump. Expressions are derived for the excitation conditions and the growth rates of electromagnetic decay instabilities (L-> T + S), electromagnetic fusion instabilities (L + S -> T) and electromagnetic oscillating two-stream instabilities (L -> T+- S * , where S * is a purely growing mode). (author) [pt

  10. A theory of the coherent fundamental plasma emission in Tokamaks

    International Nuclear Information System (INIS)

    Alves, M.V.; Chian, A.C.-L.

    1987-07-01

    A theoretical model of coherent radiation near the fundamental plasma frequency in Tokamaks is proposed. It is shown that, in the presence of runaway electrons, the beam-generated Langmuir waves (L) can be paarmetrically converted into electromagnetic waves (T) through ponderomotive coupling to ion acoustic waves (S). Two types of pumps are considered: traveling wave and standing wave pump. Expressions are derived for the excitation conditions and the growth rates of electomagnetic decay instabilities (L → T + S), electromagnetic fusion instabilities (L + S → T) and electromagnetic oscillating two-stream instabilities (L → T+-S sup(*) is a purely growing mode). (author) [pt

  11. Variations in voice level and fundamental frequency with changing background noise level and talker-to-listener distance while wearing hearing protectors: A pilot study.

    Science.gov (United States)

    Bouserhal, Rachel E; Macdonald, Ewen N; Falk, Tiago H; Voix, Jérémie

    2016-01-01

    Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Twelve participants with a mean age of 28 participated in this study. Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded quiet condition. This implies that a model can be developed to better understand speech production for the occluded ear.

  12. Development of Radio Frequency Antenna Radiation Simulation Software

    International Nuclear Information System (INIS)

    Mohamad Idris Taib; Rozaimah Abd Rahim; Noor Ezati Shuib; Wan Saffiey Wan Abdullah

    2014-01-01

    Antennas are widely used national wide for radio frequency propagation especially for communication system. Radio frequency is electromagnetic spectrum from 10 kHz to 300 GHz and non-ionizing. These radiation exposures to human being have radiation hazard risk. This software was under development using LabVIEW for radio frequency exposure calculation. For the first phase of this development, software purposely to calculate possible maximum exposure for quick base station assessment, using prediction methods. This software also can be used for educational purpose. Some results of this software are comparing with commercial IXUS and free ware NEC software. (author)

  13. Estimation of the Maximum Output Power of Double-Clad Photonic Crystal Fiber Laser

    International Nuclear Information System (INIS)

    Chen Yue-E; Wang Yong; Qu Xi-Long

    2012-01-01

    Compared with traditional optical fiber lasers, double-clad photonic crystal fiber (PCF) lasers have larger surface-area-to-volume ratios. With an increase of output power, thermal effects may severely restrict output power and deteriorate beam quality of fiber lasers. We utilize the heat-conduction equations to estimate the maximum output power of a double-clad PCF laser under natural-convection, air-cooling, and water-cooling conditions in terms of a certain surface-volume heat ratio of the PCF. The thermal effects hence define an upper power limit of double-clad PCF lasers when scaling output power. (fundamental areas of phenomenology(including applications))

  14. Different Frequencies between Power and Efficiency in Wireless Power Transfer

    OpenAIRE

    Muhammad Afnan, Habibi; Hodaka, Ichijo

    2017-01-01

    Wireless Power Transfer (WPT) has been recognized as a common power transfer method because it transfers electric power without any cable from source to the load. One of the physical principle of WPT is the law of electromagnetic induction, and the WPT system is driven by alternative current power source under specific frequency. The frequency that provides maximum gain between voltages or currents is called resonance frequency. On the other hand, some studies about WPT said that resonance fr...

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

    International Nuclear Information System (INIS)

    Swanson, D.G.

    1985-01-01

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

  16. Power system frequency estimation based on an orthogonal decomposition method

    Science.gov (United States)

    Lee, Chih-Hung; Tsai, Men-Shen

    2018-06-01

    In recent years, several frequency estimation techniques have been proposed by which to estimate the frequency variations in power systems. In order to properly identify power quality issues under asynchronously-sampled signals that are contaminated with noise, flicker, and harmonic and inter-harmonic components, a good frequency estimator that is able to estimate the frequency as well as the rate of frequency changes precisely is needed. However, accurately estimating the fundamental frequency becomes a very difficult task without a priori information about the sampling frequency. In this paper, a better frequency evaluation scheme for power systems is proposed. This method employs a reconstruction technique in combination with orthogonal filters, which may maintain the required frequency characteristics of the orthogonal filters and improve the overall efficiency of power system monitoring through two-stage sliding discrete Fourier transforms. The results showed that this method can accurately estimate the power system frequency under different conditions, including asynchronously sampled signals contaminated by noise, flicker, and harmonic and inter-harmonic components. The proposed approach also provides high computational efficiency.

  17. Understanding the influence of low-frequency vibrations on the hydrogen bonds of acetic acid and acetamide dimers.

    Science.gov (United States)

    Copeland, Christopher; Menon, Omkaran; Majumdar, D; Roszak, Szczepan; Leszczynski, Jerzy

    2017-09-20

    Low-frequency vibrations coupled to high-frequency modes are known to influence the hydrogen bond strengths in a weakly interacting dimer. In this context, various acetic acid and acetamide dimers were analyzed using Møller-Plesset second-order perturbation (MP2) and density functional theory (DFT)-based approaches with explicit anharmonicity corrections. The computed low-frequency fundamentals as well as the high-frequency modes, which were found to be related to hydrogen bonding (OH/NH stretching modes), were analyzed and their computed intensities were correlated with their hydrogen-bond strengths/binding energies. There are similarities in the nature of eight low-frequency fundamentals of these two dimers, and the in-plane bending and stretch-bend fundamentals of the different dimers of these two species (in this low-frequency region) have specific roles in their relative stability order. The computed linear correlations were further verified against the results from coupled cluster calculations including triple excitation (CCSD(T)), Gaussian-G4 (G4), Gaussian-G2-MP2 (G2MP2) and complete basis set (CBS-QB3) methods of high accuracy energy calculations. As a consequence of such linear correlations, an additive property of local fragment energies (responsible for hydrogen bonding) was found to be a valid approximation to predict the binding energies of such dimers and the idea was found to be extendable to the other homologues of these acids/amides.

  18. External-cavity high-power dual-wavelength tapered amplifier with tunable THz frequency difference

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2012-01-01

    A tunable 800 nm high-power dual-wavelength diode laser system with double-Littrow external-cavity feedback is demonstrated. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 5.0 THz. A maximum output power of 1.54 W is achie......A tunable 800 nm high-power dual-wavelength diode laser system with double-Littrow external-cavity feedback is demonstrated. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 5.0 THz. A maximum output power of 1.54 W...... is achieved with a frequency difference of 0.86 THz, the output power is higher than 1.3 W in the 5.0 THz range of frequency difference, and the amplified spontaneous emission intensity is more than 20 dB suppressed in the range of frequency difference. The beam quality factor M2 is 1.22±0.15 at an output...

  19. Perceptual Space of Superimposed Dual-Frequency Vibrations in the Hands.

    Science.gov (United States)

    Hwang, Inwook; Seo, Jeongil; Choi, Seungmoon

    2017-01-01

    The use of distinguishable complex vibrations that have multiple spectral components can improve the transfer of information by vibrotactile interfaces. We investigated the qualitative characteristics of dual-frequency vibrations as the simplest complex vibrations compared to single-frequency vibrations. Two psychophysical experiments were conducted to elucidate the perceptual characteristics of these vibrations by measuring the perceptual distances among single-frequency and dual-frequency vibrations. The perceptual distances of dual-frequency vibrations between their two frequency components along their relative intensity ratio were measured in Experiment I. The estimated perceptual spaces for three frequency conditions showed non-linear perceptual differences between the dual-frequency and single-frequency vibrations. A perceptual space was estimated from the measured perceptual distances among ten dual-frequency compositions and five single-frequency vibrations in Experiment II. The effect of the component frequency and the frequency ratio was revealed in the perceptual space. In a percept of dual-frequency vibration, the lower frequency component showed a dominant effect. Additionally, the perceptual difference among single-frequency and dual-frequency vibrations were increased with a low relative difference between two frequencies of a dual-frequency vibration. These results are expected to provide a fundamental understanding about the perception of complex vibrations to enrich the transfer of information using vibrotactile stimuli.

  20. Fundamental formulae for wave-energy conversion.

    Science.gov (United States)

    Falnes, Johannes; Kurniawan, Adi

    2015-03-01

    The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units-i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)-may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the 'added-mass' matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called 'fundamental theorem for wave power'. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies.

  1. Fundamentals of turbomachines

    CERN Document Server

    Dick, Erik

    2015-01-01

    This book explores the working principles of all kinds of turbomachines. The same theoretical framework is used to analyse the different machine types. Fundamentals are first presented and theoretical concepts are then elaborated for particular machine types, starting with the simplest ones.For each machine type, the author strikes a balance between building basic understanding and exploring knowledge of practical aspects. Readers are invited through challenging exercises to consider how the theory applies to particular cases and how it can be generalised.   The book is primarily meant as a course book. It teaches fundamentals and explores applications. It will appeal to senior undergraduate and graduate students in mechanical engineering and to professional engineers seeking to understand the operation of turbomachines. Readers will gain a fundamental understanding of turbomachines. They will also be able to make a reasoned choice of turbomachine for a particular application and to understand its operation...

  2. Anomalous Capacitance Maximum of the Glassy Carbon-Ionic Liquid Interface through Dilution with Organic Solvents.

    Science.gov (United States)

    Bozym, David J; Uralcan, Betül; Limmer, David T; Pope, Michael A; Szamreta, Nicholas J; Debenedetti, Pablo G; Aksay, Ilhan A

    2015-07-02

    We use electrochemical impedance spectroscopy to measure the effect of diluting a hydrophobic room temperature ionic liquid with miscible organic solvents on the differential capacitance of the glassy carbon-electrolyte interface. We show that the minimum differential capacitance increases with dilution and reaches a maximum value at ionic liquid contents near 5-10 mol% (i.e., ∼1 M). We provide evidence that mixtures with 1,2-dichloroethane, a low-dielectric constant solvent, yield the largest gains in capacitance near the open circuit potential when compared against two traditional solvents, acetonitrile and propylene carbonate. To provide a fundamental basis for these observations, we use a coarse-grained model to relate structural variations at the double layer to the occurrence of the maximum. Our results reveal the potential for the enhancement of double-layer capacitance through dilution.

  3. Variable Sampling Composite Observer Based Frequency Locked Loop and its Application in Grid Connected System

    Directory of Open Access Journals (Sweden)

    ARUN, K.

    2016-05-01

    Full Text Available A modified digital signal processing procedure is described for the on-line estimation of DC, fundamental and harmonics of periodic signal. A frequency locked loop (FLL incorporated within the parallel structure of observers is proposed to accommodate a wide range of frequency drift. The error in frequency generated under drifting frequencies has been used for changing the sampling frequency of the composite observer, so that the number of samples per cycle of the periodic waveform remains constant. A standard coupled oscillator with automatic gain control is used as numerically controlled oscillator (NCO to generate the enabling pulses for the digital observer. The NCO gives an integer multiple of the fundamental frequency making it suitable for power quality applications. Another observer with DC and second harmonic blocks in the feedback path act as filter and reduces the double frequency content. A systematic study of the FLL is done and a method has been proposed to design the controller. The performance of FLL is validated through simulation and experimental studies. To illustrate applications of the new FLL, estimation of individual harmonics from nonlinear load and the design of a variable sampling resonant controller, for a single phase grid-connected inverter have been presented.

  4. CODATA recommended values of the fundamental constants

    International Nuclear Information System (INIS)

    Mohr, Peter J.; Taylor, Barry N.

    2000-01-01

    A review is given of the latest Committee on Data for Science and Technology (CODATA) adjustment of the values of the fundamental constants. The new set of constants, referred to as the 1998 values, replaces the values recommended for international use by CODATA in 1986. The values of the constants, and particularly the Rydberg constant, are of relevance to the calculation of precise atomic spectra. The standard uncertainty (estimated standard deviation) of the new recommended value of the Rydberg constant, which is based on precision frequency metrology and a detailed analysis of the theory, is approximately 1/160 times the uncertainty of the 1986 value. The new set of recommended values as well as a searchable bibliographic database that gives citations to the relevant literature is available on the World Wide Web at physics.nist.gov/constants and physics.nist.gov/constantsbib, respectively

  5. Maximum entropy models of ecosystem functioning

    International Nuclear Information System (INIS)

    Bertram, Jason

    2014-01-01

    Using organism-level traits to deduce community-level relationships is a fundamental problem in theoretical ecology. This problem parallels the physical one of using particle properties to deduce macroscopic thermodynamic laws, which was successfully achieved with the development of statistical physics. Drawing on this parallel, theoretical ecologists from Lotka onwards have attempted to construct statistical mechanistic theories of ecosystem functioning. Jaynes’ broader interpretation of statistical mechanics, which hinges on the entropy maximisation algorithm (MaxEnt), is of central importance here because the classical foundations of statistical physics do not have clear ecological analogues (e.g. phase space, dynamical invariants). However, models based on the information theoretic interpretation of MaxEnt are difficult to interpret ecologically. Here I give a broad discussion of statistical mechanical models of ecosystem functioning and the application of MaxEnt in these models. Emphasising the sample frequency interpretation of MaxEnt, I show that MaxEnt can be used to construct models of ecosystem functioning which are statistical mechanical in the traditional sense using a savanna plant ecology model as an example

  6. Maximum entropy models of ecosystem functioning

    Energy Technology Data Exchange (ETDEWEB)

    Bertram, Jason, E-mail: jason.bertram@anu.edu.au [Research School of Biology, The Australian National University, Canberra ACT 0200 (Australia)

    2014-12-05

    Using organism-level traits to deduce community-level relationships is a fundamental problem in theoretical ecology. This problem parallels the physical one of using particle properties to deduce macroscopic thermodynamic laws, which was successfully achieved with the development of statistical physics. Drawing on this parallel, theoretical ecologists from Lotka onwards have attempted to construct statistical mechanistic theories of ecosystem functioning. Jaynes’ broader interpretation of statistical mechanics, which hinges on the entropy maximisation algorithm (MaxEnt), is of central importance here because the classical foundations of statistical physics do not have clear ecological analogues (e.g. phase space, dynamical invariants). However, models based on the information theoretic interpretation of MaxEnt are difficult to interpret ecologically. Here I give a broad discussion of statistical mechanical models of ecosystem functioning and the application of MaxEnt in these models. Emphasising the sample frequency interpretation of MaxEnt, I show that MaxEnt can be used to construct models of ecosystem functioning which are statistical mechanical in the traditional sense using a savanna plant ecology model as an example.

  7. Analysis of Time and Frequency Domain Pace Algorithms for OFDM with Virtual Subcarriers

    DEFF Research Database (Denmark)

    Rom, Christian; Manchón, Carles Navarro; Deneire, Luc

    2007-01-01

    This paper studies common linear frequency direction pilot-symbol aided channel estimation algorithms for orthogonal frequency division multiplexing in a UTRA long term evolution context. Three deterministic algorithms are analyzed: the maximum likelihood (ML) approach, the noise reduction algori...

  8. Applications of the principle of maximum entropy: from physics to ecology.

    Science.gov (United States)

    Banavar, Jayanth R; Maritan, Amos; Volkov, Igor

    2010-02-17

    There are numerous situations in physics and other disciplines which can be described at different levels of detail in terms of probability distributions. Such descriptions arise either intrinsically as in quantum mechanics, or because of the vast amount of details necessary for a complete description as, for example, in Brownian motion and in many-body systems. We show that an application of the principle of maximum entropy for estimating the underlying probability distribution can depend on the variables used for describing the system. The choice of characterization of the system carries with it implicit assumptions about fundamental attributes such as whether the system is classical or quantum mechanical or equivalently whether the individuals are distinguishable or indistinguishable. We show that the correct procedure entails the maximization of the relative entropy subject to known constraints and, additionally, requires knowledge of the behavior of the system in the absence of these constraints. We present an application of the principle of maximum entropy to understanding species diversity in ecology and introduce a new statistical ensemble corresponding to the distribution of a variable population of individuals into a set of species not defined a priori.

  9. Applications of the principle of maximum entropy: from physics to ecology

    International Nuclear Information System (INIS)

    Banavar, Jayanth R; Volkov, Igor; Maritan, Amos

    2010-01-01

    There are numerous situations in physics and other disciplines which can be described at different levels of detail in terms of probability distributions. Such descriptions arise either intrinsically as in quantum mechanics, or because of the vast amount of details necessary for a complete description as, for example, in Brownian motion and in many-body systems. We show that an application of the principle of maximum entropy for estimating the underlying probability distribution can depend on the variables used for describing the system. The choice of characterization of the system carries with it implicit assumptions about fundamental attributes such as whether the system is classical or quantum mechanical or equivalently whether the individuals are distinguishable or indistinguishable. We show that the correct procedure entails the maximization of the relative entropy subject to known constraints and, additionally, requires knowledge of the behavior of the system in the absence of these constraints. We present an application of the principle of maximum entropy to understanding species diversity in ecology and introduce a new statistical ensemble corresponding to the distribution of a variable population of individuals into a set of species not defined a priori. (topical review)

  10. Regional analysis of annual maximum rainfall using TL-moments method

    Science.gov (United States)

    Shabri, Ani Bin; Daud, Zalina Mohd; Ariff, Noratiqah Mohd

    2011-06-01

    Information related to distributions of rainfall amounts are of great importance for designs of water-related structures. One of the concerns of hydrologists and engineers is the probability distribution for modeling of regional data. In this study, a novel approach to regional frequency analysis using L-moments is revisited. Subsequently, an alternative regional frequency analysis using the TL-moments method is employed. The results from both methods were then compared. The analysis was based on daily annual maximum rainfall data from 40 stations in Selangor Malaysia. TL-moments for the generalized extreme value (GEV) and generalized logistic (GLO) distributions were derived and used to develop the regional frequency analysis procedure. TL-moment ratio diagram and Z-test were employed in determining the best-fit distribution. Comparison between the two approaches showed that the L-moments and TL-moments produced equivalent results. GLO and GEV distributions were identified as the most suitable distributions for representing the statistical properties of extreme rainfall in Selangor. Monte Carlo simulation was used for performance evaluation, and it showed that the method of TL-moments was more efficient for lower quantile estimation compared with the L-moments.

  11. Radiation pressure acceleration: The factors limiting maximum attainable ion energy

    Energy Technology Data Exchange (ETDEWEB)

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bulanov, S. V. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); A. M. Prokhorov Institute of General Physics RAS, Moscow 119991 (Russian Federation); Esirkepov, T. Zh.; Kando, M. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); Pegoraro, F. [Physics Department, University of Pisa and Istituto Nazionale di Ottica, CNR, Pisa 56127 (Italy); Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Berkeley, California 94720 (United States)

    2016-05-15

    Radiation pressure acceleration (RPA) is a highly efficient mechanism of laser-driven ion acceleration, with near complete transfer of the laser energy to the ions in the relativistic regime. However, there is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. The tightly focused laser pulses have group velocities smaller than the vacuum light speed, and, since they offer the high intensity needed for the RPA regime, it is plausible that group velocity effects would manifest themselves in the experiments involving tightly focused pulses and thin foils. However, in this case, finite spot size effects are important, and another limiting factor, the transverse expansion of the target, may dominate over the group velocity effect. As the laser pulse diffracts after passing the focus, the target expands accordingly due to the transverse intensity profile of the laser. Due to this expansion, the areal density of the target decreases, making it transparent for radiation and effectively terminating the acceleration. The off-normal incidence of the laser on the target, due either to the experimental setup, or to the deformation of the target, will also lead to establishing a limit on maximum ion energy.

  12. Fundamental ion cyclotron resonance heating of JET deuterium plasmas

    International Nuclear Information System (INIS)

    Krasilnikov, A V; Amosov, V N; Kaschuck, Yu A; Van Eester, D; Lerche, E; Ongena, J; Bonheure, G; Biewer, T; Crombe, K; Ericsson, G; Giacomelli, L; Hellesen, C; Hjalmarsson, A; Esposito, B; Marocco, D; Jachmich, S; Kiptily, V; Leggate, H; Mailloux, J; Kallne, J

    2009-01-01

    Radio frequency heating of majority ions is of prime importance for understanding the basic role of auxiliary heating in the activated D-T phase of ITER. Majority deuterium ion cyclotron resonance heating (ICRH) experiments at the fundamental cyclotron frequency were performed in JET. In spite of the poor antenna coupling at 25 MHz, this heating scheme proved promising when adopted in combination with D neutral beam injection (NBI). The effect of fundamental ICRH of a D population was clearly demonstrated in these experiments: by adding ∼25% of heating power the fusion power was increased up to 30-50%, depending on the type of NBI adopted. At this power level, the ion and electron temperatures increased from T i ∼ 4.0 keV and T e ∼ 4.5 keV (NBI-only phase) to T i ∼ 5.5 keV and T e ∼ 5.2 keV (ICRH + NBI phase), respectively. The increase in the neutron yield was stronger when 80 keV rather than 130 keV deuterons were injected in the plasma. It is shown that the neutron rate, the diamagnetic energy and the electron as well as the ion temperature scale roughly linearly with the applied RF power. A synergistic effect of the combined use of ICRF and NBI heating was observed: (i) the number of neutron counts measured by the neutron camera during the combined ICRF + NBI phases of the discharges exceeded the sum of the individual counts of the NBI-only and ICRF-only phases; (ii) a substantial increase in the number of slowing-down beam ions was detected by the time of flight neutron spectrometer when ICRF power was switched on; (iii) a small D subpopulation with energies slightly above the NBI launch energy was detected by the neutral particle analyzer and γ-ray spectroscopy.

  13. High frequency characterization of Galfenol minor flux density loops

    Directory of Open Access Journals (Sweden)

    Ling Weng

    2017-05-01

    Full Text Available This paper presents the first measurement of ring-shaped Galfenol’s high frequency-dependent minor flux density loops. The frequencies of applied AC magnetic field are 1k, 5k, 10k, 50k, 100k, 200k, 300k, 500 kHz. The measurements show that the cycle area between the flux density and magnetic field curves increase with increasing frequency. High frequency-dependent characterization, including coercivity, specific power loss, residual induction, and maximum relative permeability are discussed. Minor loops for different max induction are also measured and discussed at the same frequency 100 kHz. Minor loops with the same max induction 0.05 T for different frequencies 50, 100, 200, 300, 400 kHz are measured and specific power loss are discussed.

  14. High-frequency magnetic components

    CERN Document Server

    Kazimierczuk, Marian K

    2013-01-01

    A unique text on the theory and design fundaments of inductors and transformers, updated with more coverage on the optimization of magnetic devices and many new design examples The first edition is popular among a very broad audience of readers in different areas of engineering and science. This book covers the theory and design techniques of the major types of high-frequency power inductors and transformers for a variety of applications, including switching-mode power supplies (SMPS) and resonant dc-to-ac power inverters and dc-to-dc power converters. It describes eddy-current phenomena (su

  15. Implementation of linear filters for iterative penalized maximum likelihood SPECT reconstruction

    International Nuclear Information System (INIS)

    Liang, Z.

    1991-01-01

    This paper reports on six low-pass linear filters applied in frequency space implemented for iterative penalized maximum-likelihood (ML) SPECT image reconstruction. The filters implemented were the Shepp-Logan filter, the Butterworth filer, the Gaussian filter, the Hann filter, the Parzen filer, and the Lagrange filter. The low-pass filtering was applied in frequency space to projection data for the initial estimate and to the difference of projection data and reprojected data for higher order approximations. The projection data were acquired experimentally from a chest phantom consisting of non-uniform attenuating media. All the filters could effectively remove the noise and edge artifacts associated with ML approach if the frequency cutoff was properly chosen. The improved performance of the Parzen and Lagrange filters relative to the others was observed. The best image, by viewing its profiles in terms of noise-smoothing, edge-sharpening, and contrast, was the one obtained with the Parzen filter. However, the Lagrange filter has the potential to consider the characteristics of detector response function

  16. Information security fundamentals

    CERN Document Server

    Peltier, Thomas R

    2013-01-01

    Developing an information security program that adheres to the principle of security as a business enabler must be the first step in an enterprise's effort to build an effective security program. Following in the footsteps of its bestselling predecessor, Information Security Fundamentals, Second Edition provides information security professionals with a clear understanding of the fundamentals of security required to address the range of issues they will experience in the field.The book examines the elements of computer security, employee roles and r

  17. Fundamentals of statistics

    CERN Document Server

    Mulholland, Henry

    1968-01-01

    Fundamentals of Statistics covers topics on the introduction, fundamentals, and science of statistics. The book discusses the collection, organization and representation of numerical data; elementary probability; the binomial Poisson distributions; and the measures of central tendency. The text describes measures of dispersion for measuring the spread of a distribution; continuous distributions for measuring on a continuous scale; the properties and use of normal distribution; and tests involving the normal or student's 't' distributions. The use of control charts for sample means; the ranges

  18. Nonlinear generation of the fundamental radiation in plasmas: the influence of induced ion-acoustic and Langmuir waves

    International Nuclear Information System (INIS)

    Rizzato, F.B.

    1992-01-01

    A nonlinear emission mechanism of electromagnetic waves at the fundamental plasma frequency has been examined. This mechanism is based on the electromagnetic oscillating two-stream instability driven by two oppositely propagating Langmuir waves. The excitation of the electromagnetic oscillating two-stream instability is due to nonlinear wave-wave coupling involving Langmuir waves, low-frequency density waves and electromagnetic waves. The Chian and Alves model is improved using the generalized Zakharov equations. Attention is directed toward the influence of induced low-frequency and Langmuir waves on the properties of the electromagnetic oscillating two-stream instability. Presumably, the properties derived in the present context may be relevant to both space and laboratory plasmas. (author)

  19. Psychophysical basis for maximum pushing and pulling forces: A review and recommendations.

    Science.gov (United States)

    Garg, Arun; Waters, Thomas; Kapellusch, Jay; Karwowski, Waldemar

    2014-03-01

    The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers. At present it is not clear whether pushing or pulling should be favored. Similarly, it is not clear what handle heights would be optimal for pushing and pulling. Epidemiological studies are needed to determine relationships between psychophysically determined maximum acceptable pushing and pulling forces and risk of musculoskeletal injuries, in particular to low back and shoulders.

  20. Wind power limit calculation basedon frequency deviation using Matlab

    International Nuclear Information System (INIS)

    Santos Fuentefria, Ariel; Salgado Duarte, Yorlandis; MejutoFarray, Davis

    2017-01-01

    The utilization of the wind energy for the production of electricity it’s a technology that has promoted itself in the last years, like an alternative before the environmental deterioration and the scarcity of the fossil fuels. When the power generation of wind energy is integrated into the electrical power systems, maybe take place problems in the frequency stability due to, mainly, the stochastic characteristic of the wind and the impossibility of the wind power control on behalf of the dispatchers. In this work, is make an analysis of frequency deviation when the wind power generation rise in an isolated electrical power system. This analysis develops in a computerized frame with the construction of an algorithm using Matlab, which allowed to make several simulations in order to obtain the frequency behavior for different loads and wind power conditions. Besides, it was determined the wind power limit for minimum, medium and maximum load. The results show that the greatest values on wind power are obtained in maximum load condition. However, the minimum load condition limit the introduction of wind power into the system. (author)

  1. Relation Between Percent Body Fat and Fundamental Motor Skills in Pre-School Children age 3-6 years

    Directory of Open Access Journals (Sweden)

    Martin Musalek

    2017-06-01

    Full Text Available It is quite well known that excessive body fat in children is interpreted as a marker of inhibited physical activity and motor performance. This study aimed to establish whether severe impairment of fundamental motor skills (defined as performance under 5th centile of norms will be significantly more frequently identified in pre-schoolers age 3-6 years with amount of body fat higher than 85th centile of norms. Research sample consisted of 496 (females=241, males=255 pre-schoolers selected from specific district of Prague, Czech Republic. The MABC-2 was used for the assesment fundamental motor skills. Equations for body fat estimation in children identified 35.8% children with body fat˃85th centile of norms, 61.7% within 15th–85th centile, and 2.5% of children˂15th centile of norms. Results revealed that children whose body fat was higher than 85th centile of norms or lower than 15th centile had double the frequency of severe motor problems. Interestingely on the other hand we found no signficant differences in the frequency of high above average performances˃90th centile in MABC-2 between fat 8.4% and non fat children 10.7%. We suggest that amount of body fat is not a clear predictor for the degree of fundamental motor skills.

  2. Infosec management fundamentals

    CERN Document Server

    Dalziel, Henry

    2015-01-01

    Infosec Management Fundamentals is a concise overview of the Information Security management concepts and techniques, providing a foundational template for both experienced professionals and those new to the industry. This brief volume will also appeal to business executives and managers outside of infosec who want to understand the fundamental concepts of Information Security and how it impacts their business decisions and daily activities. Teaches ISO/IEC 27000 best practices on information security management Discusses risks and controls within the context of an overall information securi

  3. Spectroscopy of antiprotonic helium atoms and its contribution to the fundamental physical constants

    CERN Document Server

    Hayano, R S

    2010-01-01

    Antiprotonic helium atom, a metastable neutral system consisting of an antiproton, an electron and a helium nucleus, was serendipitously discovered, and has been studied at CERN’s antiproton decelerator facility. Its transition frequencies have recently been measured to nine digits of precision by laser spectroscopy. By comparing these experimental results with three-body QED calculations, the antiproton-to-electron massratio was determined as 1836.152674(5). This result contributed to the CODATA recommended values of the fundamental physical constants.

  4. Judging Criterion of Controlled Structures with Closely Spaced Natural Frequencies

    International Nuclear Information System (INIS)

    Xie Faxiang; Sun Limin

    2010-01-01

    The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.

  5. A quadrature frequency converter in a feedback loop of high frequency cavities in the Proton Synchrotron at CERN.

    CERN Document Server

    Truszczynski, T

    This thesis presents the author’s work during the internship at the European Laboratory for Particle Physics (CERN). The quadrature frequency converter is one of the modules that has been developed to upgrade the Proton Synchrotron RF system. Basic information about accelerators, fundamentals of IQ signal representation, mixing and phase shifting techniques are introduced. The development process of the converter is presented with the design details and measurements of the prototype board.

  6. Simple method of generating and distributing frequency-entangled qudits

    Science.gov (United States)

    Jin, Rui-Bo; Shimizu, Ryosuke; Fujiwara, Mikio; Takeoka, Masahiro; Wakabayashi, Ryota; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Gerrits, Thomas; Sasaki, Masahide

    2016-11-01

    High-dimensional, frequency-entangled photonic quantum bits (qudits for d-dimension) are promising resources for quantum information processing in an optical fiber network and can also be used to improve channel capacity and security for quantum communication. However, up to now, it is still challenging to prepare high-dimensional frequency-entangled qudits in experiments, due to technical limitations. Here we propose and experimentally implement a novel method for a simple generation of frequency-entangled qudts with d\\gt 10 without the use of any spectral filters or cavities. The generated state is distributed over 15 km in total length. This scheme combines the technique of spectral engineering of biphotons generated by spontaneous parametric down-conversion and the technique of spectrally resolved Hong-Ou-Mandel interference. Our frequency-entangled qudits will enable quantum cryptographic experiments with enhanced performances. This distribution of distinct entangled frequency modes may also be useful for improved metrology, quantum remote synchronization, as well as for fundamental test of stronger violation of local realism.

  7. Decomposition of methane to hydrogen using nanosecond pulsed plasma reactor with different active volumes, voltages and frequencies

    International Nuclear Information System (INIS)

    Khalifeh, Omid; Mosallanejad, Amin; Taghvaei, Hamed; Rahimpour, Mohammad Reza; Shariati, Alireza

    2016-01-01

    Highlights: • CH 4 conversion into H 2 is investigated in a nanosecond pulsed DBD reactor. • The absence of CO and CO 2 in the product gas is highly favorable. • Effects of external electrode length, applied voltage and frequency are examined. • The maximum efficiency of 7.23% is achieved at the electrode length of 15 cm. • The maximum CH 4 conversion of 87.2% is obtained at discharge power 268.92 W. - Abstract: In this paper, the methane conversion into hydrogen is investigated experimentally in a nanosecond pulsed DBD reactor. In order to achieve pure hydrogen production with minimum power consumption, effects of some operating parameters including external electrode length, applied voltage and pulse repetition frequency have been evaluated. Results show that although higher CH 4 conversion and H 2 concentration can be obtained at longer electrode lengths, higher applied voltages and pulse repetition frequencies, these parameters should be optimized for efficient hydrogen production. Actually, the maximum CH 4 conversion of 87.2% and maximum hydrogen percentage of 80% are obtained at the external electrode length, discharge power, voltage and frequency of 15 cm, 268.92 W, 12 kV and 10 kHz, respectively. However, the maximum efficiency of 7.23% is achieved at the external electrode length of 15 cm, applied voltage of 6 kV, pulse repetition frequency of 0.9 kHz and discharge power of 4 W. Furthermore, at this condition, due to low temperature of discharge zone very little amount of solid carbon was observed on the inner electrode surface of the reactor.

  8. Fundamentals of ergonomic exoskeleton robots

    OpenAIRE

    Schiele, A.

    2008-01-01

    This thesis is the first to provide the fundamentals of ergonomic exoskeleton design. The fundamental theory as well as technology necessary to analyze and develop ergonomic wearable robots interacting with humans is established and validated by experiments and prototypes. The fundamentals are (1) a new theoretical framework for analyzing physical human robot interaction (pHRI) with exoskeletons, and (2) a clear set of design rules of how to build wearable, portable exoskeletons to easily and...

  9. Extremely high frequency RF effects on electronics.

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  10. Classification of frequency response areas in the inferior colliculus reveals continua not discrete classes

    OpenAIRE

    Palmer, Alan R; Shackleton, Trevor M; Sumner, Christian J; Zobay, Oliver; Rees, Adrian

    2013-01-01

    A differential response to sound frequency is a fundamental property of auditory neurons. Frequency analysis in the cochlea gives rise to V-shaped tuning functions in auditory nerve fibres, but by the level of the inferior colliculus (IC), the midbrain nucleus of the auditory pathway, neuronal receptive fields display diverse shapes that reflect the interplay of excitation and inhibition. The origin and nature of these frequency receptive field types is still open to question. One proposed hy...

  11. Versatile mid-infrared frequency-comb referenced sub-Doppler spectrometer

    Science.gov (United States)

    Gambetta, A.; Vicentini, E.; Coluccelli, N.; Wang, Y.; Fernandez, T. T.; Maddaloni, P.; De Natale, P.; Castrillo, A.; Gianfrani, L.; Laporta, P.; Galzerano, G.

    2018-04-01

    We present a mid-IR high-precision spectrometer capable of performing accurate Doppler-free measurements with absolute calibration of the optical axis and high signal-to-noise ratio. The system is based on a widely tunable mid-IR offset-free frequency comb and a Quantum-Cascade-Laser (QCL). The QCL emission frequency is offset locked to one of the comb teeth to provide absolute-frequency calibration, spectral-narrowing, and accurate fine frequency tuning. Both the comb repetition frequency and QCL-comb offset frequency can be modulated to provide, respectively, slow- and fast-frequency-calibrated scanning capabilities. The characterisation of the spectrometer is demonstrated by recording sub-Doppler saturated absorption features of the CHF3 molecule at around 8.6 μm with a maximum signal-to-noise ratio of ˜7 × 103 in 10 s integration time, frequency-resolution of 160 kHz, and accuracy of less than 10 kHz.

  12. Versatile mid-infrared frequency-comb referenced sub-Doppler spectrometer

    Directory of Open Access Journals (Sweden)

    A. Gambetta

    2018-04-01

    Full Text Available We present a mid-IR high-precision spectrometer capable of performing accurate Doppler-free measurements with absolute calibration of the optical axis and high signal-to-noise ratio. The system is based on a widely tunable mid-IR offset-free frequency comb and a Quantum-Cascade-Laser (QCL. The QCL emission frequency is offset locked to one of the comb teeth to provide absolute-frequency calibration, spectral-narrowing, and accurate fine frequency tuning. Both the comb repetition frequency and QCL-comb offset frequency can be modulated to provide, respectively, slow- and fast-frequency-calibrated scanning capabilities. The characterisation of the spectrometer is demonstrated by recording sub-Doppler saturated absorption features of the CHF3 molecule at around 8.6 μm with a maximum signal-to-noise ratio of ∼7 × 103 in 10 s integration time, frequency-resolution of 160 kHz, and accuracy of less than 10 kHz.

  13. Maximum likelihood sequence estimation for optical complex direct modulation.

    Science.gov (United States)

    Che, Di; Yuan, Feng; Shieh, William

    2017-04-17

    Semiconductor lasers are versatile optical transmitters in nature. Through the direct modulation (DM), the intensity modulation is realized by the linear mapping between the injection current and the light power, while various angle modulations are enabled by the frequency chirp. Limited by the direct detection, DM lasers used to be exploited only as 1-D (intensity or angle) transmitters by suppressing or simply ignoring the other modulation. Nevertheless, through the digital coherent detection, simultaneous intensity and angle modulations (namely, 2-D complex DM, CDM) can be realized by a single laser diode. The crucial technique of CDM is the joint demodulation of intensity and differential phase with the maximum likelihood sequence estimation (MLSE), supported by a closed-form discrete signal approximation of frequency chirp to characterize the MLSE transition probability. This paper proposes a statistical method for the transition probability to significantly enhance the accuracy of the chirp model. Using the statistical estimation, we demonstrate the first single-channel 100-Gb/s PAM-4 transmission over 1600-km fiber with only 10G-class DM lasers.

  14. High precision synchronization of time and frequency and its applications

    International Nuclear Information System (INIS)

    Wang Lijun

    2014-01-01

    We discuss the concept and methods for remote synchronization of time and frequency. We discuss a recent experiment that demonstrated time and frequency synchronization via a commercial fiber network, reaching accuracy of 7 × 10 -15 /s, 5 × 10 -19 /day, and a maximum time uncertainty of less than 50 femtoseconds. We discuss synchronization methods applicable to different topologies and their important scientific applications. (authors)

  15. Measurement of attenuation coefficients of the fundamental and second harmonic waves in water

    Science.gov (United States)

    Zhang, Shuzeng; Jeong, Hyunjo; Cho, Sungjong; Li, Xiongbing

    2016-02-01

    Attenuation corrections in nonlinear acoustics play an important role in the study of nonlinear fluids, biomedical imaging, or solid material characterization. The measurement of attenuation coefficients in a nonlinear regime is not easy because they depend on the source pressure and requires accurate diffraction corrections. In this work, the attenuation coefficients of the fundamental and second harmonic waves which come from the absorption of water are measured in nonlinear ultrasonic experiments. Based on the quasilinear theory of the KZK equation, the nonlinear sound field equations are derived and the diffraction correction terms are extracted. The measured sound pressure amplitudes are adjusted first for diffraction corrections in order to reduce the impact on the measurement of attenuation coefficients from diffractions. The attenuation coefficients of the fundamental and second harmonics are calculated precisely from a nonlinear least squares curve-fitting process of the experiment data. The results show that attenuation coefficients in a nonlinear condition depend on both frequency and source pressure, which are much different from a linear regime. In a relatively lower drive pressure, the attenuation coefficients increase linearly with frequency. However, they present the characteristic of nonlinear growth in a high drive pressure. As the diffraction corrections are obtained based on the quasilinear theory, it is important to use an appropriate source pressure for accurate attenuation measurements.

  16. Communication technology update and fundamentals

    CERN Document Server

    Grant, August E

    2010-01-01

    New communication technologies are being introduced at an astonishing rate. Making sense of these technologies is increasingly difficult. Communication Technology Update and Fundamentals is the single best source for the latest developments, trends, and issues in communication technology. Featuring the fundamental framework along with the history and background of communication technologies, Communication Technology Update and Fundamentals, 12th edition helps you stay ahead of these ever-changing and emerging technologies.As always, every chapter ha

  17. Tangent hyperbolic circular frequency diverse array radars

    Directory of Open Access Journals (Sweden)

    Sarah Saeed

    2016-03-01

    Full Text Available Frequency diverse array (FDA with uniform frequency offset (UFO has been in spot light of research for past few years. Not much attention has been devoted to non-UFOs in FDA. This study investigates tangent hyperbolic (TH function for frequency offset selection scheme in circular FDAs (CFDAs. Investigation reveals a three-dimensional single-maximum beampattern, which promises to enhance system detection capability and signal-to-interference plus noise ratio. Furthermore, by utilising the versatility of TH function, a highly configurable type array system is achieved, where beampatterns of three different configurations of FDA can be generated, just by adjusting a single function parameter. This study further examines the utility of the proposed TH-CFDA in some practical radar scenarios.

  18. Individual differences in fundamental social motives.

    Science.gov (United States)

    Neel, Rebecca; Kenrick, Douglas T; White, Andrew Edward; Neuberg, Steven L

    2016-06-01

    Motivation has long been recognized as an important component of how people both differ from, and are similar to, each other. The current research applies the biologically grounded fundamental social motives framework, which assumes that human motivational systems are functionally shaped to manage the major costs and benefits of social life, to understand individual differences in social motives. Using the Fundamental Social Motives Inventory, we explore the relations among the different fundamental social motives of Self-Protection, Disease Avoidance, Affiliation, Status, Mate Seeking, Mate Retention, and Kin Care; the relationships of the fundamental social motives to other individual difference and personality measures including the Big Five personality traits; the extent to which fundamental social motives are linked to recent life experiences; and the extent to which life history variables (e.g., age, sex, childhood environment) predict individual differences in the fundamental social motives. Results suggest that the fundamental social motives are a powerful lens through which to examine individual differences: They are grounded in theory, have explanatory value beyond that of the Big Five personality traits, and vary meaningfully with a number of life history variables. A fundamental social motives approach provides a generative framework for considering the meaning and implications of individual differences in social motivation. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  19. Frequency dependence of p-mode frequency shifts induced by magnetic activity in Kepler solar-like stars

    Science.gov (United States)

    Salabert, D.; Régulo, C.; Pérez Hernández, F.; García, R. A.

    2018-04-01

    The variations of the frequencies of the low-degree acoustic oscillations in the Sun induced by magnetic activity show a dependence on radial order. The frequency shifts are observed to increase towards higher-order modes to reach a maximum of about 0.8 μHz over the 11-yr solar cycle. A comparable frequency dependence is also measured in two other main sequence solar-like stars, the F-star HD 49933, and the young 1 Gyr-old solar analog KIC 10644253, although with different amplitudes of the shifts of about 2 μHz and 0.5 μHz, respectively. Our objective here is to extend this analysis to stars with different masses, metallicities, and evolutionary stages. From an initial set of 87 Kepler solar-like oscillating stars with known individual p-mode frequencies, we identify five stars showing frequency shifts that can be considered reliable using selection criteria based on Monte Carlo simulations and on the photospheric magnetic activity proxy Sph. The frequency dependence of the frequency shifts of four of these stars could be measured for the l = 0 and l = 1 modes individually. Given the quality of the data, the results could indicate that a physical source of perturbation different from that in the Sun is dominating in this sample of solar-like stars.

  20. Prediction of flow- induced dynamic stress in an axial pump impeller using FEM

    International Nuclear Information System (INIS)

    Gao, J Y; Hou, Y S; Xi, S Z; Cai, Z H; Yao, P P; Shi, H L

    2013-01-01

    Axial pumps play an important role in water supply and flood control projects. Along with growing requirements for high reliability and large capacity, the dynamic stress of axial pumps has become a key problem. Unsteady flow is a significant reason which results structural dynamic stress of a pump. This paper reports on a flow-induced dynamic stress simulation in an axial pump impeller at three flow conditions by using FEM code. The pressure pulsation obtained from flow simulation using CFD code was set as the force boundary condition. The results show that the maximum stress of impeller appeared at joint between blade and root flange near trailing edge or joint between blade and root flange near leading edge. The dynamic stress of the two zones was investigated under three flow conditions (0.8Q d , 1.0Q d , 1.1Q d ) in time domain and frequency domain. The frequencies of stress at zones of maximum stress are 22.9Hz and 37.5Hz as the fundamental frequency and its harmonics. The fundamental frequencies are nearly equal to vane passing frequency (22.9 Hz) and 3 times blade passing frequency (37.5Hz). The first dominant frequency at zones of maximum stress is equal to the vane passing frequency due to rotor-stator interaction between the vane and the blade. This study would be helpful for axial pumps in reducing stress, improving structure design and fatigue life

  1. Spectroscopy of antiprotonic helium atoms and its contribution to the fundamental physical constants

    Science.gov (United States)

    Hayano, Ryugo S.

    2010-01-01

    Antiprotonic helium atom, a metastable neutral system consisting of an antiproton, an electron and a helium nucleus, was serendipitously discovered, and has been studied at CERN’s antiproton decelerator facility. Its transition frequencies have recently been measured to nine digits of precision by laser spectroscopy. By comparing these experimental results with three-body QED calculations, the antiproton-to-electron massratio was determined as 1836.152674(5). This result contributed to the CODATA recommended values of the fundamental physical constants. PMID:20075605

  2. Teaching the Politics of Islamic Fundamentalism.

    Science.gov (United States)

    Kazemzadeh, Masoud

    1998-01-01

    Argues that the rise of Islamic fundamentalism since the Iranian Revolution has generated a number of issues of analytical significance for political science. Describes three main models in teaching and research on Islamic fundamentalism: Islamic exceptionalism, comparative fundamentalisms, and class analysis. Discusses the construction of a…

  3. Fundamental principles of heat transfer

    CERN Document Server

    Whitaker, Stephen

    1977-01-01

    Fundamental Principles of Heat Transfer introduces the fundamental concepts of heat transfer: conduction, convection, and radiation. It presents theoretical developments and example and design problems and illustrates the practical applications of fundamental principles. The chapters in this book cover various topics such as one-dimensional and transient heat conduction, energy and turbulent transport, forced convection, thermal radiation, and radiant energy exchange. There are example problems and solutions at the end of every chapter dealing with design problems. This book is a valuable int

  4. Online frequency estimation with applications to engine and generator sets

    Science.gov (United States)

    Manngård, Mikael; Böling, Jari M.

    2017-07-01

    Frequency and spectral analysis based on the discrete Fourier transform is a fundamental task in signal processing and machine diagnostics. This paper aims at presenting computationally efficient methods for real-time estimation of stationary and time-varying frequency components in signals. A brief survey of the sliding time window discrete Fourier transform and Goertzel filter is presented, and two filter banks consisting of: (i) sliding time window Goertzel filters (ii) infinite impulse response narrow bandpass filters are proposed for estimating instantaneous frequencies. The proposed methods show excellent results on both simulation studies and on a case study using angular speed data measurements of the crankshaft of a marine diesel engine-generator set.

  5. Fundamental Astronomy

    CERN Document Server

    Karttunen, Hannu; Oja, Heikki; Poutanen, Markku; Donner, Karl Johan

    2007-01-01

    Fundamental Astronomy gives a well-balanced and comprehensive introduction to the topics of classical and modern astronomy. While emphasizing both the astronomical concepts and the underlying physical principles, the text provides a sound basis for more profound studies in the astronomical sciences. The fifth edition of this successful undergraduate textbook has been extensively modernized and extended in the parts dealing with the Milky Way, extragalactic astronomy and cosmology as well as with extrasolar planets and the solar system (as a consequence of recent results from satellite missions and the new definition by the International Astronomical Union of planets, dwarf planets and small solar-system bodies). Furthermore a new chapter on astrobiology has been added. Long considered a standard text for physical science majors, Fundamental Astronomy is also an excellent reference and entrée for dedicated amateur astronomers.

  6. Improved capacitance sensor with variable operating frequency for scanning capacitance microscopy

    International Nuclear Information System (INIS)

    Kwon, Joonhyung; Kim, Joonhui; Jeong, Jong-Hwa; Lee, Euy-Kyu; Seok Kim, Yong; Kang, Chi Jung; Park, Sang-il

    2005-01-01

    Scanning capacitance microscopy (SCM) has been gaining attention for its capability to measure local electrical properties in doping profile, oxide thickness, trapped charges and charge dynamics. In many cases, stray capacitance produced by different samples and measurement conditions affects the resonance frequency of a capacitance sensor. The applications of conventional SCM are critically limited by the fixed operating frequency and lack of tunability in its SCM sensor. In order to widen SCM application to various samples, we have developed a novel SCM sensor with variable operating frequency. By performing variable frequency sweep over the band of 160 MHz, the SCM sensor is tuned to select the best and optimized resonance frequency and quality factor for each sample measurement. The fundamental advantage of the new variable frequency SCM sensor was demonstrated in the SCM imaging of silicon oxide nano-crystals. Typical sensitivity of the variable frequency SCM sensor was found to be 10 -19 F/V

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

    DEFF Research Database (Denmark)

    Meyer, Steffen

    2017-01-01

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

  8. [Evolutionary process unveiled by the maximum genetic diversity hypothesis].

    Science.gov (United States)

    Huang, Yi-Min; Xia, Meng-Ying; Huang, Shi

    2013-05-01

    As two major popular theories to explain evolutionary facts, the neutral theory and Neo-Darwinism, despite their proven virtues in certain areas, still fail to offer comprehensive explanations to such fundamental evolutionary phenomena as the genetic equidistance result, abundant overlap sites, increase in complexity over time, incomplete understanding of genetic diversity, and inconsistencies with fossil and archaeological records. Maximum genetic diversity hypothesis (MGD), however, constructs a more complete evolutionary genetics theory that incorporates all of the proven virtues of existing theories and adds to them the novel concept of a maximum or optimum limit on genetic distance or diversity. It has yet to meet a contradiction and explained for the first time the half-century old Genetic Equidistance phenomenon as well as most other major evolutionary facts. It provides practical and quantitative ways of studying complexity. Molecular interpretation using MGD-based methods reveal novel insights on the origins of humans and other primates that are consistent with fossil evidence and common sense, and reestablished the important role of China in the evolution of humans. MGD theory has also uncovered an important genetic mechanism in the construction of complex traits and the pathogenesis of complex diseases. We here made a series of sequence comparisons among yeasts, fishes and primates to illustrate the concept of limit on genetic distance. The idea of limit or optimum is in line with the yin-yang paradigm in the traditional Chinese view of the universal creative law in nature.

  9. The non-equilibrium response of a superconductor to pair-breaking radiation measured over a broad frequency band

    Energy Technology Data Exchange (ETDEWEB)

    Visser, P. J. de, E-mail: p.j.devisser@tudelft.nl [Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Yates, S. J. C. [SRON Netherlands Institute for Space Research, Landleven 12, 9747AD Groningen (Netherlands); Guruswamy, T.; Goldie, D. J.; Withington, S. [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Neto, A.; Llombart, N. [Faculty of Electrical Engineering, Mathematics and Computer Science, Terahertz Sensing Group, Delft University of Technology, Mekelweg 4, 2628 CD Delft (Netherlands); Baryshev, A. M. [SRON Netherlands Institute for Space Research, Landleven 12, 9747AD Groningen (Netherlands); Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen (Netherlands); Klapwijk, T. M. [Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Physics Department, Moscow State Pedagogical University, Moscow 119991 (Russian Federation); Baselmans, J. J. A. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Faculty of Electrical Engineering, Mathematics and Computer Science, Terahertz Sensing Group, Delft University of Technology, Mekelweg 4, 2628 CD Delft (Netherlands)

    2015-06-22

    We have measured the absorption of terahertz radiation in a BCS superconductor over a broad range of frequencies from 200 GHz to 1.1 THz, using a broadband antenna-lens system and a tantalum microwave resonator. From low frequencies, the response of the resonator rises rapidly to a maximum at the gap edge of the superconductor. From there on, the response drops to half the maximum response at twice the pair-breaking energy. At higher frequencies, the response rises again due to trapping of pair-breaking phonons in the superconductor. In practice, this is a measurement of the frequency dependence of the quasiparticle creation efficiency due to pair-breaking in a superconductor. The efficiency, calculated from the different non-equilibrium quasiparticle distribution functions at each frequency, is in agreement with the measurements.

  10. The non-equilibrium response of a superconductor to pair-breaking radiation measured over a broad frequency band

    International Nuclear Information System (INIS)

    Visser, P. J. de; Yates, S. J. C.; Guruswamy, T.; Goldie, D. J.; Withington, S.; Neto, A.; Llombart, N.; Baryshev, A. M.; Klapwijk, T. M.; Baselmans, J. J. A.

    2015-01-01

    We have measured the absorption of terahertz radiation in a BCS superconductor over a broad range of frequencies from 200 GHz to 1.1 THz, using a broadband antenna-lens system and a tantalum microwave resonator. From low frequencies, the response of the resonator rises rapidly to a maximum at the gap edge of the superconductor. From there on, the response drops to half the maximum response at twice the pair-breaking energy. At higher frequencies, the response rises again due to trapping of pair-breaking phonons in the superconductor. In practice, this is a measurement of the frequency dependence of the quasiparticle creation efficiency due to pair-breaking in a superconductor. The efficiency, calculated from the different non-equilibrium quasiparticle distribution functions at each frequency, is in agreement with the measurements

  11. Regional maximum rainfall analysis using L-moments at the Titicaca Lake drainage, Peru

    Science.gov (United States)

    Fernández-Palomino, Carlos Antonio; Lavado-Casimiro, Waldo Sven

    2017-08-01

    The present study investigates the application of the index flood L-moments-based regional frequency analysis procedure (RFA-LM) to the annual maximum 24-h rainfall (AM) of 33 rainfall gauge stations (RGs) to estimate rainfall quantiles at the Titicaca Lake drainage (TL). The study region was chosen because it is characterised by common floods that affect agricultural production and infrastructure. First, detailed quality analyses and verification of the RFA-LM assumptions were conducted. For this purpose, different tests for outlier verification, homogeneity, stationarity, and serial independence were employed. Then, the application of RFA-LM procedure allowed us to consider the TL as a single, hydrologically homogeneous region, in terms of its maximum rainfall frequency. That is, this region can be modelled by a generalised normal (GNO) distribution, chosen according to the Z test for goodness-of-fit, L-moments (LM) ratio diagram, and an additional evaluation of the precision of the regional growth curve. Due to the low density of RG in the TL, it was important to produce maps of the AM design quantiles estimated using RFA-LM. Therefore, the ordinary Kriging interpolation (OK) technique was used. These maps will be a useful tool for determining the different AM quantiles at any point of interest for hydrologists in the region.

  12. Polycrystalline diamond RF MOSFET with MoO3 gate dielectric

    Directory of Open Access Journals (Sweden)

    Zeyang Ren

    2017-12-01

    Full Text Available We report the radio frequency characteristics of the diamond metal-oxide-semiconductor field effect transistor with MoO3 gate dielectric for the first time. The device with 2-μm gate length was fabricated on high quality polycrystalline diamond. The maximum drain current of 150 mA/mm at VGS = -5 V and the maximum transconductance of 27 mS/mm were achieved. The extrinsic cutoff frequency of 1.2 GHz and the maximum oscillation frequency of 1.9 GHz have been measured. The moderate frequency characteristics are attributed to the moderate transconductance limited by the series resistance along the channel. We expect that the frequency characteristics of the device can be improved by increasing the magnitude of gm, or fundamentally decreasing the gate-controlled channel resistance and series resistance along the channel, and down-scaling the gate length.

  13. A Fast Algorithm for Maximum Likelihood Estimation of Harmonic Chirp Parameters

    DEFF Research Database (Denmark)

    Jensen, Tobias Lindstrøm; Nielsen, Jesper Kjær; Jensen, Jesper Rindom

    2017-01-01

    . A statistically efficient estimator for extracting the parameters of the harmonic chirp model in additive white Gaussian noise is the maximum likelihood (ML) estimator which recently has been demonstrated to be robust to noise and accurate --- even when the model order is unknown. The main drawback of the ML......The analysis of (approximately) periodic signals is an important element in numerous applications. One generalization of standard periodic signals often occurring in practice are harmonic chirp signals where the instantaneous frequency increases/decreases linearly as a function of time...

  14. Cosmic shear measurement with maximum likelihood and maximum a posteriori inference

    Science.gov (United States)

    Hall, Alex; Taylor, Andy

    2017-06-01

    We investigate the problem of noise bias in maximum likelihood and maximum a posteriori estimators for cosmic shear. We derive the leading and next-to-leading order biases and compute them in the context of galaxy ellipticity measurements, extending previous work on maximum likelihood inference for weak lensing. We show that a large part of the bias on these point estimators can be removed using information already contained in the likelihood when a galaxy model is specified, without the need for external calibration. We test these bias-corrected estimators on simulated galaxy images similar to those expected from planned space-based weak lensing surveys, with promising results. We find that the introduction of an intrinsic shape prior can help with mitigation of noise bias, such that the maximum a posteriori estimate can be made less biased than the maximum likelihood estimate. Second-order terms offer a check on the convergence of the estimators, but are largely subdominant. We show how biases propagate to shear estimates, demonstrating in our simple set-up that shear biases can be reduced by orders of magnitude and potentially to within the requirements of planned space-based surveys at mild signal-to-noise ratio. We find that second-order terms can exhibit significant cancellations at low signal-to-noise ratio when Gaussian noise is assumed, which has implications for inferring the performance of shear-measurement algorithms from simplified simulations. We discuss the viability of our point estimators as tools for lensing inference, arguing that they allow for the robust measurement of ellipticity and shear.

  15. A simple frequency-scaling rule for animal communication

    Science.gov (United States)

    Fletcher, Neville H.

    2004-05-01

    Different animals use widely different frequencies for sound communication, and it is reasonable to assume that evolution has adapted these frequencies to give greatest conspecific communication distance for a given vocal effort. Acoustic analysis shows that the optimal communication frequency is inversely proportional to about the 0.4 power of the animal's body mass. Comparison with observational data indicates that this prediction is well supported in practice. For animals of a given class, for example mammals, the maximum communication distance varies about as the 0.6 power of the animal's mass. There is, however, a wide spread of observed results because of the different emphasis placed upon vocal effort in the evolution of different animal species.

  16. Theory and potentials of multi-layered plasmonic covers for multi-frequency cloaking

    International Nuclear Information System (INIS)

    Alu, Andrea; Engheta, Nader

    2008-01-01

    We have recently suggested that suitably designed plasmonic layers may cloak a given object simultaneously at multiple frequencies (Alu and Engheta 2008 Phys. Rev. Lett. 100 113901). Here, we extend our theory and fully analyze this possibility, highlighting the potentials of this plasmonic cloaking technique and its fundamental limitations dictated by the passivity and causality of the materials involved. The cloaking mechanism relies on the scattering cancellation properties of plasmonic materials. By exploiting their inherent frequency dispersion, it is possible to reduce the 'visibility' of a given object by several orders of magnitude simultaneously at multiple frequencies, such that any of the particular layers composing the cloak is responsible for noticeable reduction of scattering at each frequency of operation.

  17. Multiple political identities: revisiting the 'maximum standard'

    NARCIS (Netherlands)

    Besselink, L.F.M.; Silveira, A.; Canotilho, M.; Madeira Froufe, P.

    2013-01-01

    This paper discusses the meaning of Art. 53 of the EU Charter of Fundamental Rights - which would seem to give priority to those fundamental rights which provide higher protection - from the perspective of fundamental rights as the expression of political and constitutional identity. In doing so, it

  18. Narrow-band 1, 2, 3, 4, 8, 16 and 24 cycles/360o angular frequency filters

    Directory of Open Access Journals (Sweden)

    Simas M.L.B.

    2002-01-01

    Full Text Available We measured human frequency response functions for seven angular frequency filters whose test frequencies were centered at 1, 2, 3, 4, 8, 16 or 24 cycles/360º using a supra-threshold summation method. The seven functions of 17 experimental conditions each were measured nine times for five observers. For the arbitrarily selected filter phases, the maximum summation effect occurred at test frequency for filters at 1, 2, 3, 4 and 8 cycles/360º. For both 16 and 24 cycles/360º test frequencies, maximum summation occurred at the lower harmonics. These results allow us to conclude that there are narrow-band angular frequency filters operating somehow in the human visual system either through summation or inhibition of specific frequency ranges. Furthermore, as a general result, it appears that addition of higher angular frequencies to lower ones disturbs low angular frequency perception (i.e., 1, 2, 3 and 4 cycles/360º, whereas addition of lower harmonics to higher ones seems to improve detection of high angular frequency harmonics (i.e., 8, 16 and 24 cycles/360º. Finally, we discuss the possible involvement of coupled radial and angular frequency filters in face perception using an example where narrow-band low angular frequency filters could have a major role.

  19. Polymorph characterization of active pharmaceutical ingredients (APIs) using low-frequency Raman spectroscopy.

    Science.gov (United States)

    Larkin, Peter J; Dabros, Marta; Sarsfield, Beth; Chan, Eric; Carriere, James T; Smith, Brian C

    2014-01-01

    Polymorph detection, identification, and quantitation in crystalline materials are of great importance to the pharmaceutical industry. Vibrational spectroscopic techniques used for this purpose include Fourier transform mid-infrared (FT-MIR) spectroscopy, Fourier transform near-infrared (FT-NIR) spectroscopy, Raman spectroscopy, and terahertz (THz) and far-infrared (FIR) spectroscopy. Typically, the fundamental molecular vibrations accessed using high-frequency Raman and MIR spectroscopy or the overtone and combination of bands in the NIR spectra are used to monitor the solid-state forms of active pharmaceutical ingredients (APIs). The local environmental sensitivity of the fundamental molecular vibrations provides an indirect probe of the long-range order in molecular crystals. However, low-frequency vibrational spectroscopy provides access to the lattice vibrations of molecular crystals and, hence, has the potential to more directly probe intermolecular interactions in the solid state. Recent advances in filter technology enable high-quality, low-frequency Raman spectra to be acquired using a single-stage spectrograph. This innovation enables the cost-effective collection of high-quality Raman spectra in the 200-10 cm(-1) region. In this study, we demonstrate the potential of low-frequency Raman spectroscopy for the polymorphic characterization of APIs. This approach provides several benefits over existing techniques, including ease of sampling and more intense, information-rich band structures that can potentially discriminate among crystalline forms. An improved understanding of the relationship between the crystalline structure and the low-frequency vibrational spectrum is needed for the more widespread use of the technique.

  20. Country Fundamentals and Currency Excess Returns

    Directory of Open Access Journals (Sweden)

    Daehwan Kim

    2014-06-01

    Full Text Available We examine whether country fundamentals help explain the cross-section of currency excess returns. For this purpose, we consider fundamental variables such as default risk, foreign exchange rate regime, capital control as well as interest rate in the multi-factor model framework. Our empirical results show that fundamental factors explain a large part of the cross-section of currency excess returns. The zero-intercept restriction of the factor model is not rejected for most currencies. They also reveal that our factor model with country fundamentals performs better than a factor model with usual investment-style factors. Our main empirical results are based on 2001-2010 balanced panel data of 19 major currencies. This paper may fill the gap between country fundamentals and practitioners' strategies on currency investment.

  1. Frequency tripling of convergent beam employing crystals tiling in large-aperture high-energy laser facilities

    Science.gov (United States)

    Wang, Junhua; Li, Dazhen; Wang, Bo; Yang, Jing; Yang, Houwen; Wang, Xiaoqian; Cheng, Wenyong

    2017-11-01

    In inertial confinement fusion, ultraviolet laser damage of the fused silica lens is an important limiting factor for load capability of the laser driver. To solve this problem, a new configuration of frequency tripling is proposed in this paper. The frequency tripling crystal is placed on downstream of the focusing lens, thus sum frequency generation of fundamental frequency light and doubling frequency light occurs in the beam convergence path. The focusing lens is only irradiated by fundamental light and doubling frequency lights. Thus, its damage threshold will increase. LiB3O5 (LBO) crystals are employed as frequency tripling crystals for its larger acceptance angle and higher damage threshold than KDP/DKDP crystals'. With the limitation of acceptance angle and crystal growth size are taken into account, the tiling scheme of LBO crystals is proposed and designed optimally to adopt to the total convergence angle of 36.0 mrad. Theoretical results indicate that 3 LBO crystals titling with different cutting angles in θ direction can meet the phase matching condition. Compared with frequency tripling of parallel beam using one LBO crystal, 83.8% (93.1% with 5 LBO crystals tiling) of the frequency tripling conversion efficiency can be obtained employing this new configuration. The results of a principle experiment also support this scheme. By employing this new design, not only the load capacity of a laser driver will be significantly improved, but also the fused silica lens can be changed to K9 glass lens which has the mature technology and low cost.

  2. Spatial organization of frequency preference and selectivity in the human inferior colliculus

    OpenAIRE

    De Martino, Federico; Moerel, Michelle; van de Moortele, Pierre-Francois; Ugurbil, Kamil; Goebel, Rainer; Yacoub, Essa; Formisano, Elia

    2013-01-01

    To date, the functional organization of human auditory sub-cortical structures can only be inferred from animal models. Here we use high-resolution functional MRI at ultra-high magnetic fields (7 Tesla) to map the organization of spectral responses in the human inferior colliculus (hIC), a sub-cortical structure fundamental for sound processing. We reveal a tonotopic map with a spatial gradient of preferred frequencies approximately oriented from dorso-lateral (low frequencies) to ventro-medi...

  3. Parametric Amplification Protocol for Frequency-Modulated Magnetic Resonance Force Microscopy Signals

    Science.gov (United States)

    Harrell, Lee; Moore, Eric; Lee, Sanggap; Hickman, Steven; Marohn, John

    2011-03-01

    We present data and theoretical signal and noise calculations for a protocol using parametric amplification to evade the inherent tradeoff between signal and detector frequency noise in force-gradient magnetic resonance force microscopy signals, which are manifested as a modulated frequency shift of a high- Q microcantilever. Substrate-induced frequency noise has a 1 / f frequency dependence, while detector noise exhibits an f2 dependence on modulation frequency f . Modulation of sample spins at a frequency that minimizes these two contributions typically results in a surface frequency noise power an order of magnitude or more above the thermal limit and may prove incompatible with sample spin relaxation times as well. We show that the frequency modulated force-gradient signal can be used to excite the fundamental resonant mode of the cantilever, resulting in an audio frequency amplitude signal that is readily detected with a low-noise fiber optic interferometer. This technique allows us to modulate the force-gradient signal at a sufficiently high frequency so that substrate-induced frequency noise is evaded without subjecting the signal to the normal f2 detector noise of conventional demodulation.

  4. Religious fundamentalism and conflict

    OpenAIRE

    Muzaffer Ercan Yılmaz

    2006-01-01

    This study provides an analytical discussion for the issue of religious fundamentalism and itsrelevance to conflict, in its broader sense. It is stressed that religious fundamentalism manifests itself in twoways: nonviolent intolerance and violent intolerance. The sources of both types of intolerance and theirconnection to conflict are addressed and discussed in detail. Further research is also suggested on conditionsconnecting religion to nonviolent intolerance so as to cope with the problem...

  5. Maximum known stages and discharges of New York streams and their annual exceedance probabilities through September 2011

    Science.gov (United States)

    Wall, Gary R.; Murray, Patricia M.; Lumia, Richard; Suro, Thomas P.

    2014-01-01

    Maximum known stages and discharges at 1,400 sites on 796 streams within New York are tabulated. Stage data are reported in feet. Discharges are reported as cubic feet per second and in cubic feet per second per square mile. Drainage areas range from 0.03 to 298,800 square miles; excluding the three sites with larger drainage areas on the St. Lawrence and Niagara Rivers, which drain the Great Lakes, the maximum drainage area is 8,288 square miles (Hudson River at Albany). Most data were obtained from U.S. Geological Survey (USGS) compilations and records, but some were provided by State, local, and other Federal agencies and by private organizations. The stage and discharge information is grouped by major drainage basins and U.S. Geological Survey site number, in downstream order. Site locations and their associated drainage area, period(s) of record, stage and discharge data, and flood-frequency statistics are compiled in a Microsoft Excel spreadsheet. Flood frequencies were derived for 1,238 sites by using methods described in Bulletin 17B (Interagency Advisory Committee on Water Data, 1982), Ries and Crouse (2002), and Lumia and others (2006). Curves that “envelope” maximum discharges within their range of drainage areas were developed for each of six flood-frequency hydrologic regions and for sites on Long Island, as well as for the State of New York; the New York curve was compared with a curve derived from a plot of maximum known discharges throughout the United States. Discharges represented by the national curve range from at least 2.7 to 4.9 times greater than those represented by the New York curve for drainage areas of 1.0 and 1,000 square miles. The relative magnitudes of discharge and runoff in the six hydrologic regions of New York and Long Island suggest the largest known discharges per square mile are in the southern part of western New York and the Catskill Mountain area, and the smallest are on Long Island.

  6. Fundamental characteristics of heat conduction enhancement in oscillating viscous flow-dream pipe

    International Nuclear Information System (INIS)

    Katsuta, M.; Nagata, K.; Maruyama, Y.; Tsujimori, A.

    1991-01-01

    This paper reports that to confirm the heat conduction augmentation technique via sinusoidal oscillation experimentally and to establish a fundamental data base of this device, systematic measurements using almost identically scaled with Kurzweg's apparatus for demonstration were conducted. In this heat exchanger, the fluid occupied a capillary tube or its bundle that connected two reservoirs at different temperature; a special constructed oscillation driving unit generated a pulsed motion of working fluid. Operation took place at various tube diameters, oscillated frequency and stroke using pure water and ethanol as working liquid. As a result, a new factor so-called heat transport coefficient which indicates the heat transfer rate multiplying temperature gradient between hot and cold reservoir was introduced. This factor increased with increasing oscillated frequency and stroke, however, beyond a critical frequency, this trend disappeared. Using modified Reynolds number and stroke ratio, a new empirical formula which correlated the data regardless of the difference of working liquid was proposed. A discussion of tube bundle was also made using this correlation. Finally, an attempt was performed to correlate the data using effective thermal diffusivity predicted by simple lumped capacitance analysis and characteristic period

  7. Efficient coding schemes with power allocation using space-time-frequency spreading

    Institute of Scientific and Technical Information of China (English)

    Jiang Haining; Luo Hanwen; Tian Jifeng; Song Wentao; Liu Xingzhao

    2006-01-01

    An efficient space-time-frequency (STF) coding strategy for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximum diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirmed by corroborating numerical simulations.

  8. Fundamental uncertainty limit of optical flow velocimetry according to Heisenberg's uncertainty principle.

    Science.gov (United States)

    Fischer, Andreas

    2016-11-01

    Optical flow velocity measurements are important for understanding the complex behavior of flows. Although a huge variety of methods exist, they are either based on a Doppler or a time-of-flight measurement principle. Doppler velocimetry evaluates the velocity-dependent frequency shift of light scattered at a moving particle, whereas time-of-flight velocimetry evaluates the traveled distance of a scattering particle per time interval. Regarding the aim of achieving a minimal measurement uncertainty, it is unclear if one principle allows to achieve lower uncertainties or if both principles can achieve equal uncertainties. For this reason, the natural, fundamental uncertainty limit according to Heisenberg's uncertainty principle is derived for Doppler and time-of-flight measurement principles, respectively. The obtained limits of the velocity uncertainty are qualitatively identical showing, e.g., a direct proportionality for the absolute value of the velocity to the power of 32 and an indirect proportionality to the square root of the scattered light power. Hence, both measurement principles have identical potentials regarding the fundamental uncertainty limit due to the quantum mechanical behavior of photons. This fundamental limit can be attained (at least asymptotically) in reality either with Doppler or time-of-flight methods, because the respective Cramér-Rao bounds for dominating photon shot noise, which is modeled as white Poissonian noise, are identical with the conclusions from Heisenberg's uncertainty principle.

  9. Acoustic emission source location in plates using wavelet analysis and cross time frequency spectrum.

    Science.gov (United States)

    Mostafapour, A; Davoodi, S; Ghareaghaji, M

    2014-12-01

    In this study, the theories of wavelet transform and cross-time frequency spectrum (CTFS) are used to locate AE source with frequency-varying wave velocity in plate-type structures. A rectangular array of four sensors is installed on the plate. When an impact is generated by an artificial AE source such as Hsu-Nielsen method of pencil lead breaking (PLB) at any position of the plate, the AE signals will be detected by four sensors at different times. By wavelet packet decomposition, a packet of signals with frequency range of 0.125-0.25MHz is selected. The CTFS is calculated by the short-time Fourier transform of the cross-correlation between considered packets captured by AE sensors. The time delay is calculated when the CTFS reaches the maximum value and the corresponding frequency is extracted per this maximum value. The resulting frequency is used to calculate the group velocity of wave velocity in combination with dispersive curve. The resulted locating error shows the high precision of proposed algorithm. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Land Prices and Fundamentals

    OpenAIRE

    Koji Nakamura; Yumi Saita

    2007-01-01

    This paper examines the long-term relationship between macro economic fundamentals and the weighted-average land price indicators, which are supposed to be more appropriate than the official land price indicators when analyzing their impacts on the macro economy. In many cases, we find the cointegrating relationships between the weighted-average land price indicators and the discounted present value of land calculated based on the macro economic fundamentals indicators. We also find that the ...

  11. Fundamental volatility is regime specific

    NARCIS (Netherlands)

    Arnold, I.J.M.; MacDonald, R.; Vries, de C.G.

    2006-01-01

    A widely held notion holds that freely floating exchange rates are excessively volatile when judged against fundamentals and when moving from fixed to floating exchange rates. We re-examine the data and conclude that the disparity between the fundamentals and exchange rate volatility is more

  12. Characterization and comprehension of corona partial discharge in air under power frequency to very low frequency voltage

    Science.gov (United States)

    Yuanxiang, ZHOU; Zhongliu, ZHOU; Ling, ZHANG; Yunxiao, ZHANG; Yajun, MO; Jiantao, SUN

    2018-05-01

    For the partial discharge test of electrical equipment with large capacitance, the use of low-frequency voltage instead of power frequency voltage can effectively reduce the capacity requirements of test power supply. However, the validity of PD test under low frequency voltage needs to be evaluated. In order to investigate the influence of voltage frequency on corona discharge in the air, the discharge test of the tip-plate electrode under the frequency from 50 to 0.1 Hz is carried out based on the impulse current method. The results show that some of the main features of corona under low frequency do not change. The magnitude of discharge in a positive half cycle is obviously larger than that in a negative cycle. The magnitude of discharge and interval in positive cycle are random, while that in negative cycle are regular. With the decrease of frequency, the inception voltage increases. The variation trend of maximum and average magnitude and repetition rate of the discharge in positive and negative half cycle with the variation of voltage frequency and magnitude is demonstrated, with discussion and interpretation from the aspects of space charge transportation, effective discharge time and transition of discharge modes. There is an obvious difference in the phase resolved pattern of partial discharge and characteristic parameters of discharge patterns between power and low frequency. The experimental results can be the reference for mode identification of partial discharge under low frequency tests. The trend of the measured parameters with the variation of frequency provides more information about the insulation defect than traditional measurements under a single frequency (usually 50 Hz). Also it helps to understand the mechanism of corona discharge with an explanation of the characteristics under different frequencies.

  13. Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies

    Energy Technology Data Exchange (ETDEWEB)

    Enrique, J.M.; Duran, E.; Andujar, J.M. [Departamento de Ingenieria Electronica, de Sistemas Informaticos y Automatica, Universidad de Huelva (Spain); Sidrach-de-Cardona, M. [Departamento de Fisica Aplicada, II, Universidad de Malaga (Spain)

    2007-01-15

    The operating point of a photovoltaic generator that is connected to a load is determined by the intersection point of its characteristic curves. In general, this point is not the same as the generator's maximum power point. This difference means losses in the system performance. DC/DC converters together with maximum power point tracking systems (MPPT) are used to avoid these losses. Different algorithms have been proposed for maximum power point tracking. Nevertheless, the choice of the configuration of the right converter has not been studied so widely, although this choice, as demonstrated in this work, has an important influence in the optimum performance of the photovoltaic system. In this article, we conduct a study of the three basic topologies of DC/DC converters with resistive load connected to photovoltaic modules. This article demonstrates that there is a limitation in the system's performance according to the type of converter used. Two fundamental conclusions are derived from this study: (1) the buck-boost DC/DC converter topology is the only one which allows the follow-up of the PV module maximum power point regardless of temperature, irradiance and connected load and (2) the connection of a buck-boost DC/DC converter in a photovoltaic facility to the panel output could be a good practice to improve performance. (author)

  14. Flood frequency analysis of historical flood data under stationary and non-stationary modelling

    Science.gov (United States)

    Machado, M. J.; Botero, B. A.; López, J.; Francés, F.; Díez-Herrero, A.; Benito, G.

    2015-06-01

    Historical records are an important source of information on extreme and rare floods and fundamental to establish a reliable flood return frequency. The use of long historical records for flood frequency analysis brings in the question of flood stationarity, since climatic and land-use conditions can affect the relevance of past flooding as a predictor of future flooding. In this paper, a detailed 400 yr flood record from the Tagus River in Aranjuez (central Spain) was analysed under stationary and non-stationary flood frequency approaches, to assess their contribution within hazard studies. Historical flood records in Aranjuez were obtained from documents (Proceedings of the City Council, diaries, chronicles, memoirs, etc.), epigraphic marks, and indirect historical sources and reports. The water levels associated with different floods (derived from descriptions or epigraphic marks) were computed into discharge values using a one-dimensional hydraulic model. Secular variations in flood magnitude and frequency, found to respond to climate and environmental drivers, showed a good correlation between high values of historical flood discharges and a negative mode of the North Atlantic Oscillation (NAO) index. Over the systematic gauge record (1913-2008), an abrupt change on flood magnitude was produced in 1957 due to constructions of three major reservoirs in the Tagus headwaters (Bolarque, Entrepeñas and Buendia) controlling 80% of the watershed surface draining to Aranjuez. Two different models were used for the flood frequency analysis: (a) a stationary model estimating statistical distributions incorporating imprecise and categorical data based on maximum likelihood estimators, and (b) a time-varying model based on "generalized additive models for location, scale and shape" (GAMLSS) modelling, which incorporates external covariates related to climate variability (NAO index) and catchment hydrology factors (in this paper a reservoir index; RI). Flood frequency

  15. Function and Evolution of Vibrato-like Frequency Modulation in Mammals.

    Science.gov (United States)

    Charlton, Benjamin D; Taylor, Anna M; Reby, David

    2017-09-11

    Why do distantly related mammals like sheep, giant pandas, and fur seals produce bleats that are characterized by vibrato-like fundamental frequency (F0) modulation? To answer this question, we used psychoacoustic tests and comparative analyses to investigate whether this distinctive vocal feature has evolved to improve the perception of formants, key acoustic components of animal calls that encode important information about the caller's size and identity [1]. Psychoacoustic tests on humans confirmed that vibrato-like F0 modulation improves the ability of listeners to detect differences in the formant patterns of synthetic bleat-like stimuli. Subsequent phylogenetically controlled comparative analyses revealed that vibrato-like F0 modulation has evolved independently in six mammalian orders in vocal signals with relatively high F0 and, therefore, low spectral density (i.e., less harmonic overtones). We also found that mammals modulate the vibrato in these calls over greater frequency extents when the number of harmonic overtones per formant is low, suggesting that this is a mechanism to improve formant perception in calls with low spectral density. Our findings constitute the first evidence that formant perception in non-speech sounds is improved by fundamental frequency modulation and provide a mechanism for the convergent evolution of bleat-like calls in mammals. They also indicate that selection pressures for animals to transmit important information encoded by formant frequencies (on size and identity, for example) are likely to have been a key driver in the evolution of mammal vocal diversity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

    Science.gov (United States)

    Wintucky, Edwin G.; Simons, Rainee N.

    2014-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

  17. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  18. Auto-identification of engine fault acoustic signal through inverse trigonometric instantaneous frequency analysis

    Directory of Open Access Journals (Sweden)

    Dayong Ning

    2016-03-01

    Full Text Available The acoustic signals of internal combustion engines contain valuable information about the condition of engines. These signals can be used to detect incipient faults in engines. However, these signals are complex and composed of a faulty component and other noise signals of background. As such, engine conditions’ characteristics are difficult to extract through wavelet transformation and acoustic emission techniques. In this study, an instantaneous frequency analysis method was proposed. A new time–frequency model was constructed using a fixed amplitude and a variable cycle sine function to fit adjacent points gradually from a time domain signal. The instantaneous frequency corresponds to single value at any time. This study also introduced instantaneous frequency calculation on the basis of an inverse trigonometric fitting method at any time. The mean value of all local maximum values was then considered to identify the engine condition automatically. Results revealed that the mean of local maximum values under faulty conditions differs from the normal mean. An experiment case was also conducted to illustrate the availability of the proposed method. Using the proposed time–frequency model, we can identify engine condition and determine abnormal sound produced by faulty engines.

  19. Neutron spectra unfolding with maximum entropy and maximum likelihood

    International Nuclear Information System (INIS)

    Itoh, Shikoh; Tsunoda, Toshiharu

    1989-01-01

    A new unfolding theory has been established on the basis of the maximum entropy principle and the maximum likelihood method. This theory correctly embodies the Poisson statistics of neutron detection, and always brings a positive solution over the whole energy range. Moreover, the theory unifies both problems of overdetermined and of underdetermined. For the latter, the ambiguity in assigning a prior probability, i.e. the initial guess in the Bayesian sense, has become extinct by virtue of the principle. An approximate expression of the covariance matrix for the resultant spectra is also presented. An efficient algorithm to solve the nonlinear system, which appears in the present study, has been established. Results of computer simulation showed the effectiveness of the present theory. (author)

  20. Maximum Power from a Solar Panel

    Directory of Open Access Journals (Sweden)

    Michael Miller

    2010-01-01

    Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.

  1. Probing the Jet Turnover Frequency Dependence on Mass and Mass Accretion Rate

    Science.gov (United States)

    Hammerstein, Erica; Gültekin, Kayhan; King, Ashley

    2018-01-01

    We have examined a sample of 15 sub-Eddington supermassive black holes (SMBHs) in a variety of galaxy classifications to further understand the proposed fundamental plane of black hole activity and scaling relations between black hole masses and their radio and X-ray luminosities. This plane describes black holes from stellar-mass to supermassive. The physics probed by these sub-Eddington systems is thought to be a radiatively inefficient, jet-dominated accretion flow. By studying black holes in this regime, we can learn important information on the disk-jet connection for accreting black holes.A key factor in studying the fundamental plane is the turnover frequency — the frequency at which emission transitions from optically thick at lower frequencies to optically thin at higher frequencies. This turnover point can be measured by observing the source in both radio and X-ray. Our project aims to test the dependence of the turnover frequency on mass and mass accretion rate.Radio observations of the sample were obtained using the Karl G. Jansky Very Large Array (VLA) in the range of 5-40 GHz across four different frequency bands in A configuration to give the highest spatial resolution to focus on the core emission. Our carefully chosen sample of SMBHs with dynamically measured masses consists of two sub-samples: those with approximately constant mass accretion rate (LX/LEdd ~ 10‑7) and those with approximately constant mass (MBH ~ 108 Msun). X-ray data were obtained from archival Chandra observations. To find the turnover frequency, we used Markov Chain Monte Carlo methods to fit two power laws to the radio data and the archival X-ray data. The intersection of the radio and X-ray fits is the turnover frequency.We present the results for both subsamples of SMBHs and their relationship between the turnover frequency and X-ray luminosity, which we take to scale with mass accretion rate, and jet power derived from both radio and X-ray properties.

  2. The Physics of Ultrabroadband Frequency Comb Generation and Optimized Combs for Measurements in Fundamental Physics

    Science.gov (United States)

    2016-07-02

    order phase-matched cascaded frequency gene , high harmonic generation, fine structure constant measurements, -envelope phase stabilization, ultra fast...MHz repetition rate are generated from a picosecond fiber laser (Pritel FFL-500) before amplifica- tion in an erbium- doped fiber amplifier (EDFA). The...width from 1 to 36 nm with central wavelength tunable over 1527–1550 nm. The pump pulses were combined with the seed and injected into 9.5 m of Ge- doped

  3. Sensitivity of the Low Frequency Facility experiment around 10 Hz

    International Nuclear Information System (INIS)

    Di Virgilio, A.; Braccini, S.; Ballardin, G.; Bradaschia, C.; Cella, G.; Cuoco, E.; Dattilo, V.; Ferrante, I.; Fidecaro, F.; Frasconi, F.; Giazotto, A.; Gennai, A.; Holloway, L.H.; La Penna, P.; Losurdo, G.; Paoletti, F.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Porzio, A.; Puppo, P.; Raffaelli, F.; Rapagnani, P.; Ricci, F.; Ricciardi, J.; Solimeno, S.; Stanga, R.; Vetrano, F.; Zhang, Z.

    2004-01-01

    The reduction of thermal noise is a fundamental issue for the improvement of future gravitational wave antennas. The main purpose of the Low Frequency Facility (LFF) is to study pendulum thermal noise in the region of 10 Hz. Data at the LFF has been taking since the beginning of 2003 and has been analyzed in order to thoroughly understand the region around 10 Hz. Above 7 Hz, the displacement noise floor is at the level of 10 -14 m/√Hz, decreasing with frequency approximately as 1/ν. Seismic noise contamination is not observed above a few Hz

  4. Sensitivity of the Low Frequency Facility experiment around 10 Hz

    Energy Technology Data Exchange (ETDEWEB)

    Di Virgilio, A.; Braccini, S.; Ballardin, G.; Bradaschia, C.; Cella, G.; Cuoco, E.; Dattilo, V.; Ferrante, I.; Fidecaro, F.; Frasconi, F.; Giazotto, A.; Gennai, A.; Holloway, L.H.; La Penna, P.; Losurdo, G.; Paoletti, F.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Porzio, A.; Puppo, P.; Raffaelli, F.; Rapagnani, P.; Ricci, F.; Ricciardi, J.; Solimeno, S.; Stanga, R.; Vetrano, F.; Zhang, Z

    2004-02-23

    The reduction of thermal noise is a fundamental issue for the improvement of future gravitational wave antennas. The main purpose of the Low Frequency Facility (LFF) is to study pendulum thermal noise in the region of 10 Hz. Data at the LFF has been taking since the beginning of 2003 and has been analyzed in order to thoroughly understand the region around 10 Hz. Above 7 Hz, the displacement noise floor is at the level of 10{sup -14} m/{radical}Hz, decreasing with frequency approximately as 1/{nu}. Seismic noise contamination is not observed above a few Hz.

  5. Apparatus and method for qualitative and quantitative measurements of optical properties of turbid media using frequency-domain photon migration

    Science.gov (United States)

    Tromberg, B.J.; Tsay, T.T.; Berns, M.W.; Svaasand, L.O.; Haskell, R.C.

    1995-06-13

    Optical measurements of turbid media, that is media characterized by multiple light scattering, is provided through an apparatus and method for exposing a sample to a modulated laser beam. The light beam is modulated at a fundamental frequency and at a plurality of integer harmonics thereof. Modulated light is returned from the sample and preferentially detected at cross frequencies at frequencies slightly higher than the fundamental frequency and at integer harmonics of the same. The received radiance at the beat or cross frequencies is compared against a reference signal to provide a measure of the phase lag of the radiance and modulation ratio relative to a reference beam. The phase and modulation amplitude are then provided as a frequency spectrum by an array processor to which a computer applies a complete curve fit in the case of highly scattering samples or a linear curve fit below a predetermined frequency in the case of highly absorptive samples. The curve fit in any case is determined by the absorption and scattering coefficients together with a concentration of the active substance in the sample. Therefore, the curve fitting to the frequency spectrum can be used both for qualitative and quantitative analysis of substances in the sample even though the sample is highly turbid. 14 figs.

  6. High frequency conductivity of hot electrons in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Amekpewu, M., E-mail: mamek219@gmail.com [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, S.Y. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Musah, R. [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, N.G. [Department of Mathematics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Abukari, S.S.; Dompreh, K.A. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana)

    2016-05-01

    High frequency conductivity of hot electrons in undoped single walled achiral Carbon Nanotubes (CNTs) under the influence of ac–dc driven fields was considered. We investigated semi-classically Boltzmann's transport equation with and without the presence of the hot electrons’ source by deriving the current densities in CNTs. Plots of the normalized current density versus frequency of ac-field revealed an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong injection of hot electrons. The applied ac-field plays a twofold role of suppressing the space-charge instability in CNTs and simultaneously pumping an energy for lower frequency generation and amplification of THz radiations. These have enormous promising applications in very different areas of science and technology.

  7. An injection-locked OEO based frequency doubler independent of electrical doubler phase noise deteriorating rule

    Science.gov (United States)

    Xie, Zhengyang; Zheng, Xiaoping; Li, Shangyuan; Yan, Haozhe; Xiao, Xuedi; Xue, Xiaoxiao

    2018-06-01

    We propose an injection-locked optoelectronic oscillator (OEO) based wide-band frequency doubler, which is free from phase noise deterioration in electrical doubler, by using a dual-parallel Mach-Zehnder modulator (DPMZM). Through adjusting the optical phase shifts in different arms of the DPMZM, the doubling signal oscillates in the OEO loop while the fundamental signal takes on phase modulation over the light and vanishes at photo-detector (PD) output. By controlling power of fundamental signal the restriction of phase-noise deterioration rule in electrical doubler is totally canceled. Experimental results show that the doubler output has a better phase noise value of, for example, -117 dBc/Hz @ 10 kHz at 6 GHz with an improvement more than 17 dB and 23 dB compared with that of fundamental input and electrical doubler, respectively. Besides, the stability of this doubler output can reach to 1 . 5 × 10-14 at 1000 s averaging time. The frequency range of doubling signal is limited by the bandwidth of electrical amplifier in OEO loop.

  8. Spectral and spectral-frequency methods of investigating atmosphereless bodies of the Solar system

    International Nuclear Information System (INIS)

    Busarev, Vladimir V; Prokof'eva-Mikhailovskaya, Valentina V; Bochkov, Valerii V

    2007-01-01

    A method of reflectance spectrophotometry of atmosphereless bodies of the Solar system, its specificity, and the means of eliminating basic spectral noise are considered. As a development, joining the method of reflectance spectrophotometry with the frequency analysis of observational data series is proposed. The combined spectral-frequency method allows identification of formations with distinctive spectral features, and estimations of their sizes and distribution on the surface of atmospherelss celestial bodies. As applied to investigations of asteroids 21 Lutetia and 4 Vesta, the spectral frequency method has given us the possibility of obtaining fundamentally new information about minor planets. (instruments and methods of investigation)

  9. Fundamental number theory with applications

    CERN Document Server

    Mollin, Richard A

    2008-01-01

    An update of the most accessible introductory number theory text available, Fundamental Number Theory with Applications, Second Edition presents a mathematically rigorous yet easy-to-follow treatment of the fundamentals and applications of the subject. The substantial amount of reorganizing makes this edition clearer and more elementary in its coverage. New to the Second Edition           Removal of all advanced material to be even more accessible in scope           New fundamental material, including partition theory, generating functions, and combinatorial number theory           Expa

  10. High accuracy line positions of the ν1 fundamental band of 14N216O

    Science.gov (United States)

    AlSaif, Bidoor; Lamperti, Marco; Gatti, Davide; Laporta, Paolo; Fermann, Martin; Farooq, Aamir; Lyulin, Oleg; Campargue, Alain; Marangoni, Marco

    2018-05-01

    The ν1 fundamental band of N2O is examined by a novel spectrometer that relies on the frequency locking of an external-cavity quantum cascade laser around 7.8 μm to a near-infrared Tm:based frequency comb at 1.9 μm. Due to the large tunability, nearly 70 lines in the 1240-1310 cm-1 range of the ν1 band of N2O, from P(40) to R(31), are for the first time measured with an absolute frequency calibration and an uncertainty from 62 to 180 kHz, depending on the line. Accurate values of the spectroscopic constants of the upper state are derived from a fit of the line centers (rms ≈ 4.8 × 10-6 cm-1 or 144 kHz). The ν1 transitions presently measured in a Doppler regime validate high accuracy predictions based on sub-Doppler measurements of the ν3 and ν3-ν1 transitions.

  11. Fundamentals of structural dynamics

    CERN Document Server

    Craig, Roy R

    2006-01-01

    From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e

  12. On the undesired frequency chirping in photonic time-stretch systems

    Science.gov (United States)

    Xu, Yuxiao; Chi, Hao; Jin, Tao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

    2017-12-01

    The technique of photonic time stretch (PTS) has been intensively investigated in the past decade due to its potential in the acquisition of ultra-high speed signals. The frequency-related RF power fading in the PTS systems with double sideband (DSB) modulation has been well-known, which limits the maximum modulation frequency. Some solutions have been proposed to solve this problem. In this paper, we report another effect, i.e., undesired frequency chirping, which also relates to the performance degradation of PTS systems with DSB modulation, for the first time to our knowledge. Distinct from the nonlinearities caused by nonlinear modulation and square-law photodetection, which is common in radio frequency analog optical links, this frequency chirping originates from the addition of two beating signals with a relative delay after photodetection. A theoretical model for exactly describing the frequency chirping is presented, and is then verified by simulations. Discussion on the method to avoid the frequency chirping is also presented.

  13. Fundamental studies of fusion plasmas

    International Nuclear Information System (INIS)

    Aamodt, R.E.; Catto, P.J.; D'Ippolito, D.A.; Myra, J.R.; Russell, D.A.

    1992-01-01

    The major portion of this program is devoted to critical ICH phenomena. The topics include edge physics, fast wave propagation, ICH induced high frequency instabilities, and a preliminary antenna design for Ignitor. This research was strongly coordinated with the world's experimental and design teams at JET, Culham, ORNL, and Ignitor. The results have been widely publicized at both general scientific meetings and topical workshops including the speciality workshop on ICRF design and physics sponsored by Lodestar in April 1992. The combination of theory, empirical modeling, and engineering design in this program makes this research particularly important for the design of future devices and for the understanding and performance projections of present tokamak devices. Additionally, the development of a diagnostic of runaway electrons on TEXT has proven particularly useful for the fundamental understanding of energetic electron confinement. This work has led to a better quantitative basis for quasilinear theory and the role of magnetic vs. electrostatic field fluctuations on electron transport. An APS invited talk was given on this subject and collaboration with PPPL personnel was also initiated. Ongoing research on these topics will continue for the remainder fo the contract period and the strong collaborations are expected to continue, enhancing both the relevance of the work and its immediate impact on areas needing critical understanding

  14. MDL, Collineations and the Fundamental Matrix

    OpenAIRE

    Maybank , Steve; Sturm , Peter

    1999-01-01

    International audience; Scene geometry can be inferred from point correspondences between two images. The inference process includes the selection of a model. Four models are considered: background (or null), collineation, affine fundamental matrix and fundamental matrix. It is shown how Minimum Description Length (MDL) can be used to compare the different models. The main result is that there is little reason for preferring the fundamental matrix model over the collineation model, even when ...

  15. The Fundamental Blossoming Inequality in Chebyshev Spaces—I: Applications to Schur Functions

    KAUST Repository

    Ait-Haddou, Rachid

    2016-10-19

    A classical theorem by Chebyshev says how to obtain the minimum and maximum values of a symmetric multiaffine function of n variables with a prescribed sum. We show that, given two functions in an Extended Chebyshev space good for design, a similar result can be stated for the minimum and maximum values of the blossom of the first function with a prescribed value for the blossom of the second one. We give a simple geometric condition on the control polygon of the planar parametric curve defined by the pair of functions ensuring the uniqueness of the solution to the corresponding optimization problem. This provides us with a fundamental blossoming inequality associated with each Extended Chebyshev space good for design. This inequality proves to be a very powerful tool to derive many classical or new interesting inequalities. For instance, applied to Müntz spaces and to rational Müntz spaces, it provides us with new inequalities involving Schur functions which generalize the classical MacLaurin’s and Newton’s inequalities. This work definitely demonstrates that, via blossoms, CAGD techniques can have important implications in other mathematical domains, e.g., combinatorics.

  16. CREEP IN THE FUNDAMENTAL FREQUENCY AND STABILITY OF A SLENDER WOODEN COLUMN OF COMPOSITE SECTION

    Directory of Open Access Journals (Sweden)

    Alexandre de Macêdo Wahrhaftig

    Full Text Available ABSTRACT Creep is a phenomenon that can occur in wooden structures since wood is a viscoelastic material. Creep may change the purely elastic parameters determined in wood characterization initial tests, as its behavior depends on the rheology of the material, even under a constant stress level. Mathematically, creep can be characterized by models in which the immediate elastic deformation is increased by a viscous deformation, resulting in a temporal function. For this reason, the calculation of the natural frequency of vibration and the stability verification of a slender column should include the reducing effects of stiffness both of axial force and creep. The first one can be considered through the geometrical portion and the second one by the introduction, in the conventional portion, of a variable elasticity modulus over time, obtained in relation to the adopted rheological model. A numerical simulation was performed to evaluate the aspects above, considering a bar compressed by a force at the free end equivalent to 10% of the Euler critical force, plus its own weight, adopting a rheological model with three parameters for the variation of the elasticity modulus. The results show differences of 60% and 50% for the frequency and elasticity modulus, besides defining the exact instant of column collapse in the case of its non-observance.

  17. Virtual and composite fundamentals in the ERM

    NARCIS (Netherlands)

    Knot, KHW; Sturm, JE

    1999-01-01

    A latent-variable approach is applied to identify the appropriate driving process for fundamental exchange rates in the ERM. From the time-series characteristics of so-called "virtual fundamentals" and "composite fundamentals", a significant degree of mean reversion can be asserted. The relative

  18. Utilization of negative beat-frequencies for maximizing the update-rate of OFDR

    Science.gov (United States)

    Gabai, Haniel; Botsev, Yakov; Hahami, Meir; Eyal, Avishay

    2015-07-01

    In traditional OFDR systems, the backscattered profile of a sensing fiber is inefficiently duplicated to the negative band of spectrum. In this work, we present a new OFDR design and algorithm that remove this redundancy and make use of negative beat frequencies. In contrary to conventional OFDR designs, it facilitates efficient use of the available system bandwidth and enables distributed sensing with the maximum allowable interrogation update-rate for a given fiber length. To enable the reconstruction of negative beat frequencies an I/Q type receiver is used. In this receiver, both the in-phase (I) and quadrature (Q) components of the backscatter field are detected. Following detection, both components are digitally combined to produce a complex backscatter signal. Accordingly, due to its asymmetric nature, the produced spectrum will not be corrupted by the appearance of negative beat-frequencies. Here, via a comprehensive computer simulation, we show that in contrast to conventional OFDR systems, I/Q OFDR can be operated at maximum interrogation update-rate for a given fiber length. In addition, we experimentally demonstrate, for the first time, the ability of I/Q OFDR to utilize negative beat-frequencies for long-range distributed sensing.

  19. Maximum entropy principle and hydrodynamic models in statistical mechanics

    International Nuclear Information System (INIS)

    Trovato, M.; Reggiani, L.

    2012-01-01

    This review presents the state of the art of the maximum entropy principle (MEP) in its classical and quantum (QMEP) formulation. Within the classical MEP we overview a general theory able to provide, in a dynamical context, the macroscopic relevant variables for carrier transport in the presence of electric fields of arbitrary strength. For the macroscopic variables the linearized maximum entropy approach is developed including full-band effects within a total energy scheme. Under spatially homogeneous conditions, we construct a closed set of hydrodynamic equations for the small-signal (dynamic) response of the macroscopic variables. The coupling between the driving field and the energy dissipation is analyzed quantitatively by using an arbitrary number of moments of the distribution function. Analogously, the theoretical approach is applied to many one-dimensional n + nn + submicron Si structures by using different band structure models, different doping profiles, different applied biases and is validated by comparing numerical calculations with ensemble Monte Carlo simulations and with available experimental data. Within the quantum MEP we introduce a quantum entropy functional of the reduced density matrix, the principle of quantum maximum entropy is then asserted as fundamental principle of quantum statistical mechanics. Accordingly, we have developed a comprehensive theoretical formalism to construct rigorously a closed quantum hydrodynamic transport within a Wigner function approach. The theory is formulated both in thermodynamic equilibrium and nonequilibrium conditions, and the quantum contributions are obtained by only assuming that the Lagrange multipliers can be expanded in powers of ħ 2 , being ħ the reduced Planck constant. In particular, by using an arbitrary number of moments, we prove that: i) on a macroscopic scale all nonlocal effects, compatible with the uncertainty principle, are imputable to high-order spatial derivatives both of the

  20. Parametric time-frequency domain spatial audio

    CERN Document Server

    Delikaris-Manias, Symeon; Politis, Archontis

    2018-01-01

    This book provides readers with the principles and best practices in spatial audio signal processing. It describes how sound fields and their perceptual attributes are captured and analyzed within the time-frequency domain, how essential representation parameters are coded, and how such signals are efficiently reproduced for practical applications. The book is split into four parts starting with an overview of the fundamentals. It then goes on to explain the reproduction of spatial sound before offering an examination of signal-dependent spatial filtering. The book finishes with coverage of both current and future applications and the direction that spatial audio research is heading in. Parametric Time-frequency Domain Spatial Audio focuses on applications in entertainment audio, including music, home cinema, and gaming--covering the capturing and reproduction of spatial sound as well as its generation, transduction, representation, transmission, and perception. This book will teach readers the tools needed...

  1. Identification of Natural Frequency of Low Rise Building on Soft Ground Profile using Ambient Vibration Method

    Science.gov (United States)

    Kamarudin, A. F.; Zainal Abidin, M. H.; Mokhatar, S. N.; Daud, M. E.; Ibrahim, A.; Ibrahim, Z.; Noh, M. S. Md

    2018-04-01

    Natural frequency is the rate at which a body to vibrate or oscillate. Application of ambient vibration (AV) excitation is widely used nowadays as the input motion for building predominant frequency, fo, and ground fundamental frequency, Fo, prediction due to simple, fast, non-destructive, simple handling operation and reliable result. However, it must be emphasized and caution to isolate these frequencies (fo and Fo) from spurious frequencies of site-structure effects especially to low rise building on soft ground deposit. In this study, identification of fo and Fo by using AV measurements were performed on ground and 4-storey primary school reinforced concrete (RC) building at Sekolah Kebangsaan (SK) Sg. Tongkang, Rengit, Johor using 1 Hz of tri-axial seismometer sensor. Overlapping spectra between Fourier Amplitude Spectra (FAS) from and Horizontal to Vertical Spectra Ratio (HVSR) were used to distinguish respective frequencies of building and ground natural frequencies. Three dominant frequencies were identified from the FAS curves at 1.91 Hz, 1.98 Hz and 2.79 Hz in longitudinal (East West-EW), transverse (North South-NS) and vertical (UD) directions. It is expected the building has deformed in translational mode based on the first peak frequency by respective NS and EW components of FAS spectrum. Vertical frequency identified from the horizontal spectrums, might induces to the potential of rocking effect experienced by the school building. Meanwhile, single peak HVSR spectrum at low ground fundamental frequency concentrated at 0.93 Hz indicates to the existence deep contrast of soft deposit. Strong interaction between ground and building at similar frequency (0.93 Hz) observed from the FAS curves on the highest floor has shown the building to behave as a dependent unit against ground response as one rigid mass.

  2. Fundamentals of Geophysics

    Science.gov (United States)

    Frohlich, Cliff

    Choosing an intermediate-level geophysics text is always problematic: What should we teach students after they have had introductory courses in geology, math, and physics, but little else? Fundamentals of Geophysics is aimed specifically at these intermediate-level students, and the author's stated approach is to construct a text “using abundant diagrams, a simplified mathematical treatment, and equations in which the student can follow each derivation step-by-step.” Moreover, for Lowrie, the Earth is round, not flat—the “fundamentals of geophysics” here are the essential properties of our Earth the planet, rather than useful techniques for finding oil and minerals. Thus this book is comparable in both level and approach to C. M. R. Fowler's The Solid Earth (Cambridge University Press, 1990).

  3. Design and Manufacture an Ultrasonic Dispersion System with Automatic Frequency Adjusting Property

    Directory of Open Access Journals (Sweden)

    Herlina ABDUL RAHIM

    2011-03-01

    Full Text Available This paper a novel ultrasonic dispersion system for the cleaning application or dispersing of particles which are mixed in liquid has been proposed. The frequency band of designed system is 30 kHz so that the frequency of ultrasonic wave sweeps from 30 kHz to 60 kHz with 100 Hz steps. One of the superiority of manufactured system in compare with the other similar systems which are available in markets is that this system can transfer the maximum and optimum energy of ultrasonic wave inside the liquid tank with the high efficiency in the whole of the usage time of the system. The used ultrasonic transducers in this system as the generator of ultrasonic wave is the type of air coupled ceramic ultrasonic piezoelectric with the nominal maximum power 50 Watt. The frequency characteristic of applied piezoelectric is that it produces the maximum amplitude of ultrasonic wave on the resonance frequency, so this system is designed to work on resonance frequency of piezoelectric, continuously. This is done by the use of control system which is consisted of two major parts, sensing part and controlling part. The manufactured ultrasonic dispersion system is consisted of 9 piezoelectrics so that it can produce 450 watt ultrasonic energy, totally. The main purpose of this project is to produce a safety system especially for fatigue car driver so as to prevent from accidents. The statistic on road fatality shows that human error constitute of 64.84 % road accidents fatality and 17.4 % due to technical factors. These systems encompassed the approach of hand pressure applied on the steering wheel. The steering will be installed with pressure sensors. At the same time these sensors can be used to measure gripping force while driving.

  4. Fundamentals of continuum mechanics

    CERN Document Server

    Rudnicki, John W

    2014-01-01

    A concise introductory course text on continuum mechanics Fundamentals of Continuum Mechanics focuses on the fundamentals of the subject and provides the background for formulation of numerical methods for large deformations and a wide range of material behaviours. It aims to provide the foundations for further study, not just of these subjects, but also the formulations for much more complex material behaviour and their implementation computationally.  This book is divided into 5 parts, covering mathematical preliminaries, stress, motion and deformation, balance of mass, momentum and energ

  5. Investigation of the relationship between the gray zone and the clock frequency of a Josephson comparator

    International Nuclear Information System (INIS)

    Haddad, T; Engert, S; Toepfer, H; Wetzstein, O; Ortlepp, T

    2011-01-01

    The Josephson comparator is one of the fundamental building blocks of rapid single flux quantum (RSFQ) electronics. Within this circuit family it is the exclusive device which provides logical data processing. The Josephson comparator is also the basic decision element for very fast analog-to-digital converters and sampler circuits for low input power and high-bandwidth signals based on the RSFQ technique. The performance of those devices is fundamentally determined by the characteristics of the Josephson comparator. In this study the gray zone dependency on the clock frequency of a Josephson comparator is investigated by simulations concerning the influence of thermal noise. This investigation is performed for a series of operating points defined by the bias current and different noise levels defined by the operating temperature. In contrast to former investigations, we analyzed the comparator embedded in a realistic environment for output data processing. We identified a characteristic clock frequency f c for a comparator topology designed for a 1 kA cm -2 niobium fabrication technology. The gray zone of 8 μA remains constant for clock frequencies below f c = 15 GHz and starts to increase for larger frequencies. We also found out that this characteristic frequency is independent of the intensity of thermal noise and therefore independent of temperature.

  6. Atomic spectroscopy and highly accurate measurement: determination of fundamental constants

    International Nuclear Information System (INIS)

    Schwob, C.

    2006-12-01

    This document reviews the theoretical and experimental achievements of the author concerning highly accurate atomic spectroscopy applied for the determination of fundamental constants. A pure optical frequency measurement of the 2S-12D 2-photon transitions in atomic hydrogen and deuterium has been performed. The experimental setting-up is described as well as the data analysis. Optimized values for the Rydberg constant and Lamb shifts have been deduced (R = 109737.31568516 (84) cm -1 ). An experiment devoted to the determination of the fine structure constant with an aimed relative uncertainty of 10 -9 began in 1999. This experiment is based on the fact that Bloch oscillations in a frequency chirped optical lattice are a powerful tool to transfer coherently many photon momenta to the atoms. We have used this method to measure accurately the ratio h/m(Rb). The measured value of the fine structure constant is α -1 = 137.03599884 (91) with a relative uncertainty of 6.7*10 -9 . The future and perspectives of this experiment are presented. This document presented before an academic board will allow his author to manage research work and particularly to tutor thesis students. (A.C.)

  7. Frequency and temperature dependent mobility of a charged carrier and randomly interrupted strand

    International Nuclear Information System (INIS)

    Kumar, N.; Jayannavar, A.M.

    1981-05-01

    Randomly interrupted strand model of a one-dimensional conductor is considered. Exact analytical expression is obtained for the temperature dependent as mobility for a finite segment drawn at random, taking into account the reflecting barriers at the two open ends. The real part of mobility shows a broad resonance as a function of both frequency and tempeature, and vanishes quadratically in the dc limit. The frequency (temperature) maximum shifts to higher values for higher temperatures (frequencies). (author)

  8. Stator and Rotor Faults Diagnosis of Squirrel Cage Motor Based on Fundamental Component Extraction Method

    Directory of Open Access Journals (Sweden)

    Guoqing An

    2017-01-01

    Full Text Available Nowadays, stator current analysis used for detecting the incipient fault in squirrel cage motor has received much attention. However, in the case of interturn short circuit in stator, the traditional symmetrical component method has lost the precondition due to the harmonics and noise; the negative sequence component (NSC is hard to be obtained accurately. For broken rotor bars, the new added fault feature blanked by fundamental component is also difficult to be discriminated in the current spectrum. To solve the above problems, a fundamental component extraction (FCE method is proposed in this paper. On one hand, via the antisynchronous speed coordinate (ASC transformation, NSC of extracted signals is transformed into the DC value. The amplitude of synthetic vector of NSC is used to evaluate the severity of stator fault. On the other hand, the extracted fundamental component can be filtered out to make the rotor fault feature emerge from the stator current spectrum. Experiment results indicate that this method is feasible and effective in both interturn short circuit and broken rotor bars fault diagnosis. Furthermore, only stator currents and voltage frequency are needed to be recorded, and this method is easy to implement.

  9. The MCE (Maximum Credible Earthquake) - an approach to reduction of seismic risk

    International Nuclear Information System (INIS)

    Asmis, G.J.K.; Atchison, R.J.

    1979-01-01

    It is the responsibility of the Regulatory Body (in Canada, the AECB) to ensure that radiological risks resulting from the effects of earthquakes on nuclear facilities, do not exceed acceptable levels. In simplified numerical terms this means that the frequency of an unacceptable radiation dose must be kept below 10 -6 per annum. Unfortunately, seismic events fall into the class of external events which are not well defined at these low frequency levels. Thus, design earthquakes have been chosen, at the 10 -3 - 10 -4 frequency level, a level commensurate with the limits of statistical data. There exists, therefore, a need to define an additional level of earthquake. A seismic design explicitly and implicitly recognizes three levels of earthquake loading; one comfortably below yield, one at or about yield, and one at ultimate. The ultimate level earthquake, contrary to the first two, has been implicitly addressed by conscientious designers by choosing systems, materials and details compatible with postulated dynamic forces. It is the purpose of this paper to discuss the regulatory specifications required to quantify this third level, or Maximum Credible Earthquake (MCE). (orig.)

  10. Phase inversion and frequency doubling of reflection high-energy electron diffraction intensity oscillations in the layer-by-layer growth of complex oxides

    Science.gov (United States)

    Mao, Zhangwen; Guo, Wei; Ji, Dianxiang; Zhang, Tianwei; Gu, Chenyi; Tang, Chao; Gu, Zhengbin; Nie*, Yuefeng; Pan, Xiaoqing

    In situ reflection high-energy electron diffraction (RHEED) and its intensity oscillations are extremely important for the growth of epitaxial thin films with atomic precision. The RHEED intensity oscillations of complex oxides are, however, rather complicated and a general model is still lacking. Here, we report the unusual phase inversion and frequency doubling of RHEED intensity oscillations observed in the layer-by-layer growth of SrTiO3 using oxide molecular beam epitaxy. In contacts to the common understanding that the maximum(minimum) intensity occurs at SrO(TiO2) termination, respectively, we found that both maximum or minimum intensities can occur at SrO, TiO2, or even incomplete terminations depending on the incident angle of the electron beam, which raises a fundamental question if one can rely on the RHEED intensity oscillations to precisely control the growth of thin films. A general model including surface roughness and termination dependent mean inner potential qualitatively explains the observed phenomena, and provides the answer to the question how to prepare atomically and chemically precise surface/interfaces using RHEED oscillations for complex oxides. We thank National Basic Research Program of China (No. 11574135, 2015CB654901) and the National Thousand-Young-Talents Program.

  11. Allowable shipment frequencies for the transport of toxic gases near nuclear power plants

    International Nuclear Information System (INIS)

    Bennett, D.E.; Heath, D.C.

    1982-10-01

    One part of the safety analysis of offsite hazards for a nuclear power plant is consideration of accidents which could release toxic gases or vapors and thus jeopardize plant safety through incapacitation of the control room operators. The purpose of this work is to provide generic, bounding estimates of the maximum allowable shipping frequencies for the transport of a chemical near the plant, such that the regulatory criteria for the protection of the operators are met. A probabilistic methodology was developed and then applied to the truck and rail transport of an example chemical, chlorine. The current regulatory criteria are discussed in detail. For this study, a maximum allowable probability of occurrence of operator incapacitation of 10 - 5 per year was used in the example calculation for each mode of transport. Comprehensive tables of conditional probabilities are presented. Maximum allowable ahipping frequencies are then derived. These frequencies could be used as part of a generic, bounding criterion for the screening of toxic hazards safety analyses. Unless a transport survey assures shipping frequencies within 8 km of the plant on the order of or lower than 4/week for rail or 35/week for truck, the contol room should be isolatable and the shipping frequency then determines the degree of isolation needed. The need for isolation implies the need for toxic chemical detection at the air intake.For a self-detection case in which the smell threshold is significantly lower than the incapacitation threshold and the control room is isolatable, the corresponding trequencies are 11/week for rail or 115/week for truck. Self-contained breathing equipment is assumed to be used after 5 minutes

  12. Fundamentals - longitudinal motion

    International Nuclear Information System (INIS)

    Weng, W.T.

    1989-01-01

    There are many ways to accelerate charged particles to high energy for physics research. Each has served its purpose but eventually has encountered fundamental limitations of one kind or another. Looking at the famous Livingston curve, the initial birth and final level-off of all types of accelerators is seen. In fact, in the mid-80s we personally witnessed the creation of a new type of collider - the Stanford Linear Collider. Also witnessed, was the resurgence of study into novel methods of acceleration. This paper will cover acceleration and longitudinal motion in a synchrotron. A synchrotron is a circular accelerator with the following three characteristics: (1) Magnetic guiding (dipole) and confinement (quadrupole) components are placed in a small neighborhood around the equilibrium orbit. (2) Particles are kept in resonance with the radio-frequency electric field indefinitely to achieve acceleration to higher energies. (3) Magnetic fields are varied adiabatically with the energy of the particle. D. Edwards described the transverse oscillations of particles in a synchrotron. Here the author talks about the longitudinal oscillations of particles. The phase stability principle was invented by V. Veksler and E. McMillan independently in 1945. The phase stability and strong focusing principle, invented by Courant and Livingston in 1952, enabled the steady energy gain of accelerators and storage rings witnessed during the past 30 years. This paper is a unified overview of the related rf subjects in an accelerator and a close coupling between accelerator physics and engineering practices, which is essential for the major progress in areas such as high intensity synchrotrons, a multistage accelerator complex, and anti-proton production and cooling, made possible in the past 20 years

  13. Digital frequency offset-locked He–Ne laser system with high beat frequency stability, narrow optical linewidth and optical fibre output

    Science.gov (United States)

    Sternkopf, Christian; Manske, Eberhard

    2018-06-01

    We report on the enhancement of a previously-presented heterodyne laser source on the basis of two phase-locked loop (PLL) frequency coupled internal-mirror He–Ne lasers. Our new system consists of two digitally controlled He–Ne lasers with slightly different wavelengths, and offers high-frequency stability and very narrow optical linewidth. The digitally controlled system has been realized by using a FPGA controller and transconductance amplifiers. The light of both lasers was coupled into separate fibres for heterodyne interferometer applications. To enhance the laser performance we observed the sensitivity of both laser tubes to electromagnetic noise from various laser power supplies and frequency control systems. Furthermore, we describe how the linewidth of a frequency-controlled He–Ne laser can be reduced during precise frequency stabilisation. The digitally controlled laser source reaches a standard beat frequency deviation of less than 20 Hz (with 1 s gate time) and a spectral full width at half maximum (FWHM) of the beat signal less than 3 kHz. The laser source has enough optical output power to serve a fibre-coupled multi axis heterodyne interferometer. The system can be adjusted to output beat frequencies in the range of 0.1 MHz–20 MHz.

  14. Ecological prediction with nonlinear multivariate time-frequency functional data models

    Science.gov (United States)

    Yang, Wen-Hsi; Wikle, Christopher K.; Holan, Scott H.; Wildhaber, Mark L.

    2013-01-01

    Time-frequency analysis has become a fundamental component of many scientific inquiries. Due to improvements in technology, the amount of high-frequency signals that are collected for ecological and other scientific processes is increasing at a dramatic rate. In order to facilitate the use of these data in ecological prediction, we introduce a class of nonlinear multivariate time-frequency functional models that can identify important features of each signal as well as the interaction of signals corresponding to the response variable of interest. Our methodology is of independent interest and utilizes stochastic search variable selection to improve model selection and performs model averaging to enhance prediction. We illustrate the effectiveness of our approach through simulation and by application to predicting spawning success of shovelnose sturgeon in the Lower Missouri River.

  15. Joint maximum-likelihood magnitudes of presumed underground nuclear test explosions

    Science.gov (United States)

    Peacock, Sheila; Douglas, Alan; Bowers, David

    2017-08-01

    Body-wave magnitudes (mb) of 606 seismic disturbances caused by presumed underground nuclear test explosions at specific test sites between 1964 and 1996 have been derived from station amplitudes collected by the International Seismological Centre (ISC), by a joint inversion for mb and station-specific magnitude corrections. A maximum-likelihood method was used to reduce the upward bias of network mean magnitudes caused by data censoring, where arrivals at stations that do not report arrivals are assumed to be hidden by the ambient noise at the time. Threshold noise levels at each station were derived from the ISC amplitudes using the method of Kelly and Lacoss, which fits to the observed magnitude-frequency distribution a Gutenberg-Richter exponential decay truncated at low magnitudes by an error function representing the low-magnitude threshold of the station. The joint maximum-likelihood inversion is applied to arrivals from the sites: Semipalatinsk (Kazakhstan) and Novaya Zemlya, former Soviet Union; Singer (Lop Nor), China; Mururoa and Fangataufa, French Polynesia; and Nevada, USA. At sites where eight or more arrivals could be used to derive magnitudes and station terms for 25 or more explosions (Nevada, Semipalatinsk and Mururoa), the resulting magnitudes and station terms were fixed and a second inversion carried out to derive magnitudes for additional explosions with three or more arrivals. 93 more magnitudes were thus derived. During processing for station thresholds, many stations were rejected for sparsity of data, obvious errors in reported amplitude, or great departure of the reported amplitude-frequency distribution from the expected left-truncated exponential decay. Abrupt changes in monthly mean amplitude at a station apparently coincide with changes in recording equipment and/or analysis method at the station.

  16. Prior and posterior probabilistic models of uncertainties in a model for producing voice

    International Nuclear Information System (INIS)

    Cataldo, Edson; Sampaio, Rubens; Soize, Christian

    2010-01-01

    The aim of this paper is to use Bayesian statistics to update a probability density function related to the tension parameter, which is one of the main parameters responsible for the changing of the fundamental frequency of a voice signal, generated by a mechanical/mathematical model for producing voiced sounds. We follow a parametric approach for stochastic modeling, which requires the adoption of random variables to represent the uncertain parameters present in the cited model. For each random variable, a probability density function is constructed using the Maximum Entropy Principle and the Monte Carlo method is used to generate voice signals as the output of the model. Then, a probability density function of the voice fundamental frequency is constructed. The random variables are fit to experimental data so that the probability density function of the fundamental frequency obtained by the model can be as near as possible of a probability density function obtained from experimental data. New values are obtained experimentally for the fundamental frequency and they are used to update the probability density function of the tension parameter, via Bayes's Theorem.

  17. Fundamental role of bistability in optimal homeostatic control

    Science.gov (United States)

    Wang, Guanyu

    2013-03-01

    Bistability is a fundamental phenomenon in nature and has a number of fine properties. However, these properties are consequences of bistability at the physiological level, which do not explain why it had to emerge during evolution. Using optimal homeostasis as the first principle and Pontryagin's Maximum Principle as the optimization approach, I find that bistability emerges as an indispensable control mechanism. Because the mathematical model is general and the result is independent of parameters, it is likely that most biological systems use bistability to control homeostasis. Glucose homeostasis represents a good example. It turns out that bistability is the only solution to a dilemma in glucose homeostasis: high insulin efficiency is required for rapid plasma glucose clearance, whereas an insulin sparing state is required to guarantee the brain's safety during fasting. This new perspective can illuminate studies on the twin epidemics of obesity and diabetes and the corresponding intervening strategies. For example, overnutrition and sedentary lifestyle may represent sudden environmental changes that cause the lose of optimality, which may contribute to the marked rise of obesity and diabetes in our generation.

  18. Temporal and spatio-temporal vibrotactile displays for voice fundamental frequency: an initial evaluation of a new vibrotactile speech perception aid with normal-hearing and hearing-impaired individuals.

    Science.gov (United States)

    Auer, E T; Bernstein, L E; Coulter, D C

    1998-10-01

    Four experiments were performed to evaluate a new wearable vibrotactile speech perception aid that extracts fundamental frequency (F0) and displays the extracted F0 as a single-channel temporal or an eight-channel spatio-temporal stimulus. Specifically, we investigated the perception of intonation (i.e., question versus statement) and emphatic stress (i.e., stress on the first, second, or third word) under Visual-Alone (VA), Visual-Tactile (VT), and Tactile-Alone (TA) conditions and compared performance using the temporal and spatio-temporal vibrotactile display. Subjects were adults with normal hearing in experiments I-III and adults with severe to profound hearing impairments in experiment IV. Both versions of the vibrotactile speech perception aid successfully conveyed intonation. Vibrotactile stress information was successfully conveyed, but vibrotactile stress information did not enhance performance in VT conditions beyond performance in VA conditions. In experiment III, which involved only intonation identification, a reliable advantage for the spatio-temporal display was obtained. Differences between subject groups were obtained for intonation identification, with more accurate VT performance by those with normal hearing. Possible effects of long-term hearing status are discussed.

  19. Pragmatic electrical engineering fundamentals

    CERN Document Server

    Eccles, William

    2011-01-01

    Pragmatic Electrical Engineering: Fundamentals introduces the fundamentals of the energy-delivery part of electrical systems. It begins with a study of basic electrical circuits and then focuses on electrical power. Three-phase power systems, transformers, induction motors, and magnetics are the major topics.All of the material in the text is illustrated with completely-worked examples to guide the student to a better understanding of the topics. This short lecture book will be of use at any level of engineering, not just electrical. Its goal is to provide the practicing engineer with a practi

  20. Fundamental problem of forensic mathematics--the evidential value of a rare haplotype.

    Science.gov (United States)

    Brenner, Charles H

    2010-10-01

    Y-chromosomal and mitochondrial haplotyping offer special advantages for criminal (and other) identification. For different reasons, each of them is sometimes detectable in a crime stain for which autosomal typing fails. But they also present special problems, including a fundamental mathematical one: When a rare haplotype is shared between suspect and crime scene, how strong is the evidence linking the two? Assume a reference population sample is available which contains n-1 haplotypes. The most interesting situation as well as the most common one is that the crime scene haplotype was never observed in the population sample. The traditional tools of product rule and sample frequency are not useful when there are no components to multiply and the sample frequency is zero. A useful statistic is the fraction κ of the population sample that consists of "singletons" - of once-observed types. A simple argument shows that the probability for a random innocent suspect to match a previously unobserved crime scene type is (1-κ)/n - distinctly less than 1/n, likely ten times less. The robust validity of this model is confirmed by testing it against a range of population models. This paper hinges above all on one key insight: probability is not frequency. The common but erroneous "frequency" approach adopts population frequency as a surrogate for matching probability and attempts the intractable problem of guessing how many instances exist of the specific haplotype at a certain crime. Probability, by contrast, depends by definition only on the available data. Hence if different haplotypes but with the same data occur in two different crimes, although the frequencies are different (and are hopelessly elusive), the matching probabilities are the same, and are not hard to find. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

  1. Maximum gravitational-wave energy emissible in magnetar flares

    Science.gov (United States)

    Corsi, Alessandra; Owen, Benjamin J.

    2011-05-01

    Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (˜1049erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc.MNRAA40035-8711 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 1048-1049erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

  2. Maximum gravitational-wave energy emissible in magnetar flares

    International Nuclear Information System (INIS)

    Corsi, Alessandra; Owen, Benjamin J.

    2011-01-01

    Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (∼10 49 erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc. 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 10 48 -10 49 erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

  3. Second harmonic generation in a bounded magnetoplasma

    International Nuclear Information System (INIS)

    Thomas, D.G.

    1975-01-01

    An experimental study of second harmonic generation in a magnetized plasma contained in a cylindrical cavity resonator shows how the harmonic power varies with fundamental power, background gas pressure, and magnetization. Two cavities were designed. For each the TM010 resonance was in the S-band and the TM011 resonance in the C-band. Both frequencies were harmonically related when the d.c. discharge sustaining the plasma was adjusted to give plasma frequencies of approximately 0.7 GHz and 1.53 GHz. The experimental results show the harmonic power approximately proportional to the square of the fundamental power from 5 to 100 mw, and a decreasing function of pressure from 10 to 150 millitorr. Experiments at constant plasma frequency and varying magnetic field from 0 to 3000 Gauss show a sharp drop in harmonic power to undetectable levels when the electron cyclotron frequency approximates either the fundamental or second harmonic frequencies. These effects are attributed, respectively, to the coupling of fundamental power to other modes and to cavity detuning away from the harmonic. With the plasma frequency adjusted to maintain simultaneous resonance of fundamental and harmonic, a harmonic signal maximum occurred when the upper hybrid frequency approximated the harmonic frequency. Several anomalies, apparently related to the magnetization, background gas, and electron density distribution were observed. Otherwise, the results are qualitatively consistent with the first order theory for a cold, collisional plasma

  4. Assessment of risk for falls and its frequency among patients in a long term care institution

    OpenAIRE

    Varnelo, Ilona

    2016-01-01

    SUMMARY Vilnius University Faculty of Medicine Department of Nursing and Fundamentals of Internal Medicine Bachelor of Nursing Program Assessment of Risk for Falls and its Frequency Among Patients in a Long Term Care Institution Nursing Bachelor's thesis The Author: student Ilona Varnelo, nursing bachelor program at Vilnius University. Work Leader: assistant Viktorija Kielaitė, Vilnius University, Faculty of Medicine, Department of Nursing and Fundamentals of Internal Medicine 16 – 05 – 2016,...

  5. Frequency-shift vs phase-shift characterization of in-liquid quartz crystal microbalance applications

    International Nuclear Information System (INIS)

    Montagut, Y. J.; Garcia, J. V.; Jimenez, Y.; Arnau, A.; March, C.; Montoya, A.

    2011-01-01

    The improvement of sensitivity in quartz crystal microbalance (QCM) applications has been addressed in the last decades by increasing the sensor fundamental frequency, following the increment of the frequency/mass sensitivity with the square of frequency predicted by Sauerbrey. However, this sensitivity improvement has not been completely transferred in terms of resolution. The decrease of frequency stability due to the increase of the phase noise, particularly in oscillators, made impossible to reach the expected resolution. A new concept of sensor characterization at constant frequency has been recently proposed. The validation of the new concept is presented in this work. An immunosensor application for the detection of a low molecular weight contaminant, the insecticide carbaryl, has been chosen for the validation. An, in principle, improved version of a balanced-bridge oscillator is validated for its use in liquids, and applied for the frequency shift characterization of the QCM immunosensor application. The classical frequency shift characterization is compared with the new phase-shift characterization concept and system proposed.

  6. A Study of a Two Stage Maximum Power Point Tracking Control of a Photovoltaic System under Partially Shaded Insolation Conditions

    Science.gov (United States)

    Kobayashi, Kenji; Takano, Ichiro; Sawada, Yoshio

    A photovoltaic array shows relatively low output power density, and has a greatly drooping Current-Voltage (I-V) characteristic. Therefore, Maximum Power Point Tracking (MPPT) control is used to maximize the output power of the array. Many papers have been reported in relation to MPPT. However, the Current-Power (I-P) curve sometimes shows multi-local maximum points mode under non-uniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output point which is not the real maximal output point on the I-P curve. Some papers have been also reported, trying to avoid this difficulty. However most of those control systems become rather complicated. Then, the two stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under non-uniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and LabVIEW. In addition, simulated experiment confirms fundament al operation of the two stage MPPT control.

  7. Duel frequency echo data acquisition system for sea-floor classification

    Digital Repository Service at National Institute of Oceanography (India)

    Navelkar, G.S.; Desai, R.G.P.; Chakraborty, B.

    An echo data acquisition system is designed to digitize echo signal from a single beam shipboard echo-sounder for use in sea-floor classification studies using a 12 bit analog to digital (A/D) card with a maximum sampling frequency of 1 MHz. Both 33...

  8. Arithmetic fundamental groups and moduli of curves

    International Nuclear Information System (INIS)

    Makoto Matsumoto

    2000-01-01

    This is a short note on the algebraic (or sometimes called arithmetic) fundamental groups of an algebraic variety, which connects classical fundamental groups with Galois groups of fields. A large part of this note describes the algebraic fundamental groups in a concrete manner. This note gives only a sketch of the fundamental groups of the algebraic stack of moduli of curves. Some application to a purely topological statement, i.e., an obstruction to the subjectivity of Johnson homomorphisms in the mapping class groups, which comes from Galois group of Q, is explained. (author)

  9. Constant physics and characteristics of fundamental constant

    International Nuclear Information System (INIS)

    Tarrach, R.

    1998-01-01

    We present some evidence which supports a surprising physical interpretation of the fundamental constants. First, we relate two of them through the renormalization group. This leaves as many fundamental constants as base units. Second, we introduce and a dimensional system of units without fundamental constants. Third, and most important, we find, while interpreting the units of the a dimensional system, that is all cases accessible to experimentation the fundamental constants indicate either discretization at small values or boundedness at large values of the corresponding physical quantity. (Author) 12 refs

  10. Maximum concentrations at work and maximum biologically tolerable concentration for working materials 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The meaning of the term 'maximum concentration at work' in regard of various pollutants is discussed. Specifically, a number of dusts and smokes are dealt with. The valuation criteria for maximum biologically tolerable concentrations for working materials are indicated. The working materials in question are corcinogeneous substances or substances liable to cause allergies or mutate the genome. (VT) [de

  11. Ion beam analysis fundamentals and applications

    CERN Document Server

    Nastasi, Michael; Wang, Yongqiang

    2015-01-01

    Ion Beam Analysis: Fundamentals and Applications explains the basic characteristics of ion beams as applied to the analysis of materials, as well as ion beam analysis (IBA) of art/archaeological objects. It focuses on the fundamentals and applications of ion beam methods of materials characterization.The book explains how ions interact with solids and describes what information can be gained. It starts by covering the fundamentals of ion beam analysis, including kinematics, ion stopping, Rutherford backscattering, channeling, elastic recoil detection, particle induced x-ray emission, and nucle

  12. Effect of frequency on amplitude-dependent internal friction in niobium

    International Nuclear Information System (INIS)

    Ide, Naoki; Atsumi, Tomohiro; Nishino, Yoichi

    2006-01-01

    Amplitude-dependent internal friction (ADIF) was measured in a polycrystalline niobium using four modes of flexural vibration from the fundamental to the third-order resonance at room temperature. The ADIF was detected in each vibration mode. The internal-friction versus strain-amplitude curve of the ADIF shifted to a larger strain-amplitude range as frequency increased. The stress-strain curves were derived from the ADIF data, and the microplastic flow stress defined as the stress required to produce a plastic strain of 1 x 10 -9 was read from the stress-strain curves. It was found that the microplastic flow stress was proportional to the frequency

  13. Effect of frequency on amplitude-dependent internal friction in niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ide, Naoki [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)]. E-mail: ide@nitech.ac.jp; Atsumi, Tomohiro [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nishino, Yoichi [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2006-12-20

    Amplitude-dependent internal friction (ADIF) was measured in a polycrystalline niobium using four modes of flexural vibration from the fundamental to the third-order resonance at room temperature. The ADIF was detected in each vibration mode. The internal-friction versus strain-amplitude curve of the ADIF shifted to a larger strain-amplitude range as frequency increased. The stress-strain curves were derived from the ADIF data, and the microplastic flow stress defined as the stress required to produce a plastic strain of 1 x 10{sup -9} was read from the stress-strain curves. It was found that the microplastic flow stress was proportional to the frequency.

  14. 40 CFR 1042.140 - Maximum engine power, displacement, power density, and maximum in-use engine speed.

    Science.gov (United States)

    2010-07-01

    ... cylinders having an internal diameter of 13.0 cm and a 15.5 cm stroke length, the rounded displacement would... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Maximum engine power, displacement... Maximum engine power, displacement, power density, and maximum in-use engine speed. This section describes...

  15. Children's early reading vocabulary: description and word frequency lists.

    Science.gov (United States)

    Stuart, Morag; Dixon, Maureen; Masterson, Jackie; Gray, Bob

    2003-12-01

    When constructing stimuli for experimental investigations of cognitive processes in early reading development, researchers have to rely on adult or American children's word frequency counts, as no such counts exist for English children. The present paper introduces a database of children's early reading vocabulary, for use by researchers and teachers. Texts from 685 books from reading schemes and story books read by 5-7 year-old children were used in the construction of the database. All words from the 685 books were typed or scanned into an Oracle database. The resulting up-to-date word frequency list of early print exposure in the UK is available in two forms from a website address given in this paper. This allows access to one list of the words ordered alphabetically and one list of the words ordered by frequency. We also briefly address some fundamental issues underlying early reading vocabulary (e.g., that it is heavily skewed towards low frequencies). Other characteristics of the vocabulary are then discussed. We hope the word frequency lists will be of use to researchers seeking to control word frequency, and to teachers interested in the vocabulary to which young children are exposed in their reading material.

  16. Credal Networks under Maximum Entropy

    OpenAIRE

    Lukasiewicz, Thomas

    2013-01-01

    We apply the principle of maximum entropy to select a unique joint probability distribution from the set of all joint probability distributions specified by a credal network. In detail, we start by showing that the unique joint distribution of a Bayesian tree coincides with the maximum entropy model of its conditional distributions. This result, however, does not hold anymore for general Bayesian networks. We thus present a new kind of maximum entropy models, which are computed sequentially. ...

  17. Different Variants of Fundamental Portfolio

    Directory of Open Access Journals (Sweden)

    Tarczyński Waldemar

    2014-06-01

    Full Text Available The paper proposes the fundamental portfolio of securities. This portfolio is an alternative for the classic Markowitz model, which combines fundamental analysis with portfolio analysis. The method’s main idea is based on the use of the TMAI1 synthetic measure and, in limiting conditions, the use of risk and the portfolio’s rate of return in the objective function. Different variants of fundamental portfolio have been considered under an empirical study. The effectiveness of the proposed solutions has been related to the classic portfolio constructed with the help of the Markowitz model and the WIG20 market index’s rate of return. All portfolios were constructed with data on rates of return for 2005. Their effectiveness in 2006- 2013 was then evaluated. The studied period comprises the end of the bull market, the 2007-2009 crisis, the 2010 bull market and the 2011 crisis. This allows for the evaluation of the solutions’ flexibility in various extreme situations. For the construction of the fundamental portfolio’s objective function and the TMAI, the study made use of financial and economic data on selected indicators retrieved from Notoria Serwis for 2005.

  18. Maximum Entropy in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Tseng

    2014-07-01

    Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.

  19. High accuracy line positions of the ν 1 fundamental band of 14 N 2 16 O

    KAUST Repository

    Alsaif, Bidoor

    2018-03-08

    The ν1 fundamental band of N2O is examined by a novel spectrometer that relies on the frequency locking of an external-cavity quantum cascade laser around 7.8 μm to a near-infrared Tm:based frequency comb at 1.9 μm. Due to the large tunability, nearly 70 lines in the 1240 – 1310 cm−1 range of the ν1 band of N2O, from P(40) to R(31), are for the first time measured with an absolute frequency calibration and an uncertainty from 62 to 180 kHz, depending on the line. Accurate values of the spectroscopic constants of the upper state are derived from a fit of the line centers (rms ≈ 4.8 × 10−6 cm−1 or 144 kHz). The ν1 transitions presently measured in a Doppler regime validate high accuracy predictions based on sub-Doppler measurements of the ν3 and ν3-ν1 transitions.

  20. Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches

    DEFF Research Database (Denmark)

    Larsen, Jon Steffen; Santos, Ilmar; von Osmanski, Alexander Sebastian

    2016-01-01

    . This paper compares two fundamental methods for predicting the OSI. One is based on a nonlinear time domain simulation and another is based on a linearised frequency domain method and a perturbation of the Reynolds equation. Both methods are based on equivalent models and should predict similar results......High speed direct drive motors enable the use of Air Foil Bearings (AFB) in a wide range of applications due to the elimination of gear forces. Unfortunately, AFB supported rotors are lightly damped, and an accurate prediction of their Onset Speed of Instability (OSI) is therefore important...

  1. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  2. Skeletal maturation, fundamental motor skills and motor performance in preschool children.

    Science.gov (United States)

    Freitas, D L; Lausen, B; Maia, J A; Gouveia, É R; Antunes, A M; Thomis, M; Lefevre, J; Malina, R M

    2018-06-01

    Relationships among skeletal age (SA), body size and fundamental motor skills (FMS) and motor performance were considered in 155 boys and 159 girls 3-6 years of age. Stature and body mass were measured. SA of the hand-wrist was assessed with the Tanner-Whitehouse II 20 bone method. The Test of Gross Motor Development, 2 nd edition (TGMD-2) and the Preschool Test Battery were used, respectively, to assess FMS and motor performance. Based on hierarchical regression analyses, the standardized residuals of SA on chronological age (SAsr) explained a maximum of 6.1% of the variance in FMS and motor performance in boys (ΔR 2 3 , range 0.0% to 6.1%) and a maximum of 20.4% of the variance in girls (ΔR 2 3 , range 0.0% to 20.4%) over that explained by body size and interactions of SAsr with body size (step 3). The interactions of the SAsr and stature and body mass (step 2) explained a maximum of 28.3% of the variance in boys (ΔR 2 2 , range 0.5% to 28.3%) and 16.7% of the variance in girls (ΔR 2 2 , range 0.7% to 16.7%) over that explained by body size alone. With the exception of balance, relationships among SAsr and FMS or motor performance differed between boys and girls. Overall, SA per se or interacting with body size had a relatively small influence in FMS and motor performance in children 3-6 years of age. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. Dopant density from maximum-minimum capacitance ratio of implanted MOS structures

    International Nuclear Information System (INIS)

    Brews, J.R.

    1982-01-01

    For uniformly doped structures, the ratio of the maximum to the minimum high frequency capacitance determines the dopant ion density per unit volume. Here it is shown that for implanted structures this 'max-min' dopant density estimate depends upon the dose and depth of the implant through the first moment of the depleted portion of the implant. A a result, the 'max-min' estimate of dopant ion density reflects neither the surface dopant density nor the average of the dopant density over the depletion layer. In particular, it is not clear how this dopant ion density estimate is related to the flatband capacitance. (author)

  4. Prediction of scour depth in gravel bed rivers using radio frequency IDs : application to the Skagit River.

    Science.gov (United States)

    2013-10-01

    The overarching goal of the proposed research was to develop, test and verify a robust system based on the Low Frequency (134.2 : kHz), passive Radio Frequency Identification (RFID) technology to be ultimately used for determining the maximum scour d...

  5. Fundamentals of piping design

    CERN Document Server

    Smith, Peter

    2013-01-01

    Written for the piping engineer and designer in the field, this two-part series helps to fill a void in piping literature,since the Rip Weaver books of the '90s were taken out of print at the advent of the Computer Aid Design(CAD) era. Technology may have changed, however the fundamentals of piping rules still apply in the digitalrepresentation of process piping systems. The Fundamentals of Piping Design is an introduction to the designof piping systems, various processes and the layout of pipe work connecting the major items of equipment forthe new hire, the engineering student and the vetera

  6. Frequency stabilized HeNe gas laser with 3.5 mW from a single mode

    NARCIS (Netherlands)

    Ellis, J.D.; Voigt, D.; Spronck, J.W.; Verlaan, A.L.; Munnig Schmidt, R.H.

    2012-01-01

    This paper describes an optical frequency stabilization technique using a three-mode Helium Neon laser at 632.8 nm. Using this configuration, a maximum frequency stability relative to an iodine stabilized laser of 6×10 -12 (71 s integration time) was achieved. Two long term measurements of 62 h and

  7. Presence of strong harmonics during visual entrainment: a magnetoencephalography study.

    Science.gov (United States)

    Heinrichs-Graham, Elizabeth; Wilson, Tony W

    2012-09-01

    Visual neurons are known to synchronize their firing with stimuli that flicker at a constant rate (e.g. 12Hz). These so-called visual steady-state responses (VSSR) are a well-studied phenomenon, yet the underlying mechanisms are widely disagreed upon. Furthermore, there is limited evidence that visual neurons may simultaneously synchronize at harmonics of the stimulation frequency. We utilized magnetoencephalography (MEG) to examine synchronization at harmonics of the visual stimulation frequency (18Hz). MEG data were analyzed for event-related-synchronization (ERS) at the fundamental frequency, 36, 54, and 72Hz. We found strong ERS in all bands. Only 31% of participants showed maximum entrainment at the fundamental; others showed stronger entrainment at either 36 or 54Hz. The cortical foci of these responses indicated that the harmonics involved cortices that were partially distinct from the fundamental. These findings suggest that spatially-overlapping subpopulations of neurons are simultaneously entrained at different harmonics of the stimulus frequency. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Electromagnetic interference modeling and suppression techniques in variable-frequency drive systems

    Science.gov (United States)

    Yang, Le; Wang, Shuo; Feng, Jianghua

    2017-11-01

    Electromagnetic interference (EMI) causes electromechanical damage to the motors and degrades the reliability of variable-frequency drive (VFD) systems. Unlike fundamental frequency components in motor drive systems, high-frequency EMI noise, coupled with the parasitic parameters of the trough system, are difficult to analyze and reduce. In this article, EMI modeling techniques for different function units in a VFD system, including induction motors, motor bearings, and rectifierinverters, are reviewed and evaluated in terms of applied frequency range, model parameterization, and model accuracy. The EMI models for the motors are categorized based on modeling techniques and model topologies. Motor bearing and shaft models are also reviewed, and techniques that are used to eliminate bearing current are evaluated. Modeling techniques for conventional rectifierinverter systems are also summarized. EMI noise suppression techniques, including passive filter, Wheatstone bridge balance, active filter, and optimized modulation, are reviewed and compared based on the VFD system models.

  9. Comparative analysis of internal friction and natural frequency measured by free decay and forced vibration

    International Nuclear Information System (INIS)

    Wang, Y. Z.; Ding, X. D.; Xiong, X. M.; Zhang, J. X.

    2007-01-01

    Relations between various values of the internal friction (tgδ, Q -1 , Q -1* , and Λ/π) measured by free decay and forced vibration are analyzed systemically based on a fundamental mechanical model in this paper. Additionally, relations between various natural frequencies, such as vibration frequency of free decay ω FD , displacement-resonant frequency of forced vibration ω d , and velocity-resonant frequency of forced vibration ω 0 are calculated. Moreover, measurement of natural frequencies of a copper specimen of 99.9% purity has been made to demonstrate the relation between the measured natural frequencies of the system by forced vibration and free decay. These results are of importance for not only more accurate measurement of the elastic modulus of materials but also the data conversion between different internal friction measurements

  10. A general formula for computing maximum proportion correct scores in various psychophysical paradigms with arbitrary probability distributions of stimulus observations.

    Science.gov (United States)

    Dai, Huanping; Micheyl, Christophe

    2015-05-01

    Proportion correct (Pc) is a fundamental measure of task performance in psychophysics. The maximum Pc score that can be achieved by an optimal (maximum-likelihood) observer in a given task is of both theoretical and practical importance, because it sets an upper limit on human performance. Within the framework of signal detection theory, analytical solutions for computing the maximum Pc score have been established for several common experimental paradigms under the assumption of Gaussian additive internal noise. However, as the scope of applications of psychophysical signal detection theory expands, the need is growing for psychophysicists to compute maximum Pc scores for situations involving non-Gaussian (internal or stimulus-induced) noise. In this article, we provide a general formula for computing the maximum Pc in various psychophysical experimental paradigms for arbitrary probability distributions of sensory activity. Moreover, easy-to-use MATLAB code implementing the formula is provided. Practical applications of the formula are illustrated, and its accuracy is evaluated, for two paradigms and two types of probability distributions (uniform and Gaussian). The results demonstrate that Pc scores computed using the formula remain accurate even for continuous probability distributions, as long as the conversion from continuous probability density functions to discrete probability mass functions is supported by a sufficiently high sampling resolution. We hope that the exposition in this article, and the freely available MATLAB code, facilitates calculations of maximum performance for a wider range of experimental situations, as well as explorations of the impact of different assumptions concerning internal-noise distributions on maximum performance in psychophysical experiments.

  11. Objective voice parameters in Colombian school workers with healthy voices

    NARCIS (Netherlands)

    L.C. Cantor Cutiva (Lady Catherine); A. Burdorf (Alex)

    2015-01-01

    textabstractObjectives: To characterize the objective voice parameters among school workers, and to identify associated factors of three objective voice parameters, namely fundamental frequency, sound pressure level and maximum phonation time. Materials and methods: We conducted a cross-sectional

  12. Weighted Maximum-Clique Transversal Sets of Graphs

    OpenAIRE

    Chuan-Min Lee

    2011-01-01

    A maximum-clique transversal set of a graph G is a subset of vertices intersecting all maximum cliques of G. The maximum-clique transversal set problem is to find a maximum-clique transversal set of G of minimum cardinality. Motivated by the placement of transmitters for cellular telephones, Chang, Kloks, and Lee introduced the concept of maximum-clique transversal sets on graphs in 2001. In this paper, we study the weighted version of the maximum-clique transversal set problem for split grap...

  13. Low-frequency and wideband vibration energy harvester with flexible frame and interdigital structure

    Energy Technology Data Exchange (ETDEWEB)

    Li, Pengwei, E-mail: lipengwei@tyut.edu.cn; Wang, Yanfen; Luo, Cuixian; Li, Gang; Hu, Jie; Zhang, Wendong [MicroNano System Research Center of College of Information Engineering and Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Liu, Ying [MicroNano System Research Center of College of Information Engineering and Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Baicheng Ordnance Test Center of China, Baicheng 137000, Jilin (China); Liu, Wei [Baicheng Ordnance Test Center of China, Baicheng 137000, Jilin (China)

    2015-04-15

    As an alternative to traditional cantilever beam structures and their evolutions, a flexible beam based, interdigital structure, vibration energy harvester has been presented and investigated. The proposed interdigital-shaped oscillator consists of a rectangular flexible frame and series of cantilever beams interdigitally bonded to it. In order to achieve low frequency and wide-bandwidth harvesting, Young’s modulus of materials, frame size and the amount of the cantilevers have been studied systematically. The measured frequency responses of the designed device (PDMS frame, quintuple piezoelectric cantilever beams) show a 460% increase in bandwidth below 80Hz. When excited at an acceleration of 1.0 g, the energy harvester achieves to a maximum open-circuit voltage of 65V, and the maximum output power 4.5 mW.

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  15. Wireless power transmission to an electromechanical receiver using low-frequency magnetic fields

    International Nuclear Information System (INIS)

    Challa, Vinod R; Arnold, David P; Mur-Miranda, Jose Oscar

    2012-01-01

    A near-field, electrodynamically coupled wireless power transmission system is presented that delivers electrical power from a transmitter coil to a compact electromechanical receiver. The system integrates electromechanical energy conversion and mechanical resonance to deliver power over a range of distances using low-amplitude, low-frequency magnetic fields. Two different receiver orientations are investigated that rely on either the force or the torque induced on the receiver magnet at separation distances ranging from 2.2 to 10.2 cm. Theoretical models for each mode compare the predicted performance with the experimental results. For a 7.1 mA pk sinusoidal current supplied to a transmitter coil with a 100 cm diameter, the torque mode receiver orientation has a maximum power transfer of 150 μW (efficiency of 12%) at 2.2 cm at its resonance frequency of 38.4 Hz. For the same input current to the transmitter, the force mode receiver orientation has a maximum power transfer of 37 μW (efficiency of 4.1%) at 3.1 cm at its resonance frequency of 38.9 Hz. (paper)

  16. Ion Acoustic Wave Frequencies and Onset Times During Type 3 Solar Radio Bursts

    Science.gov (United States)

    Cairns, Iver H.; Robinson, P. A.

    1995-01-01

    frequency overlap provides support for a previous suggestion that fundamental emission occurs when the EM decay is stimulated by the ES decay product waves. The periods in which the ES and EM decays produce observable S waves are consistent with the observed and (independently) predicted times of fundamental and harmonic radio emission. This supports interpretation of fundamental emission as stimulated EM decay and harmonic emission as the coalescence L + L(prime) yields T of beam-generated L waves and L(prime) waves produced by the ES decay, where T denotes an electromagnetic wave at twice the plasma frequency. Analysis of the electron beam data reveals that the time-varying beam speed is consistent with ballistic beam propagation with minimal energy loss, implying that the beam propagates in a state close to time- and volume-averaged marginal stability. This confirms a central tenet of the stochastic growth theory for type III bursts.

  17. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  18. Climate, orography and scale controls on flood frequency in Triveneto (Italy

    Directory of Open Access Journals (Sweden)

    S. Persiano

    2016-05-01

    Full Text Available The growing concern about the possible effects of climate change on flood frequency regime is leading Authorities to review previously proposed reference procedures for design-flood estimation, such as national flood frequency models. Our study focuses on Triveneto, a broad geographical region in North-eastern Italy. A reference procedure for design flood estimation in Triveneto is available from the Italian NCR research project "VA.PI.", which considered Triveneto as a single homogeneous region and developed a regional model using annual maximum series (AMS of peak discharges that were collected up to the 1980s by the former Italian Hydrometeorological Service. We consider a very detailed AMS database that we recently compiled for 76 catchments located in Triveneto. All 76 study catchments are characterized in terms of several geomorphologic and climatic descriptors. The objective of our study is threefold: (1 to inspect climatic and scale controls on flood frequency regime; (2 to verify the possible presence of changes in flood frequency regime by looking at changes in time of regional L-moments of annual maximum floods; (3 to develop an updated reference procedure for design flood estimation in Triveneto by using a focused-pooling approach (i.e. Region of Influence, RoI. Our study leads to the following conclusions: (1 climatic and scale controls on flood frequency regime in Triveneto are similar to the controls that were recently found in Europe; (2 a single year characterized by extreme floods can have a remarkable influence on regional flood frequency models and analyses for detecting possible changes in flood frequency regime; (3 no significant change was detected in the flood frequency regime, yet an update of the existing reference procedure for design flood estimation is highly recommended and we propose the RoI approach for properly representing climate and scale controls on flood frequency in Triveneto, which cannot be regarded

  19. Frequency Response of Synthetic Vocal Fold Models with Linear and Nonlinear Material Properties

    Science.gov (United States)

    Shaw, Stephanie M.; Thomson, Scott L.; Dromey, Christopher; Smith, Simeon

    2012-01-01

    Purpose: The purpose of this study was to create synthetic vocal fold models with nonlinear stress-strain properties and to investigate the effect of linear versus nonlinear material properties on fundamental frequency (F[subscript 0]) during anterior-posterior stretching. Method: Three materially linear and 3 materially nonlinear models were…

  20. Maximum relative speeds of living organisms: Why do bacteria perform as fast as ostriches?

    Science.gov (United States)

    Meyer-Vernet, Nicole; Rospars, Jean-Pierre

    2016-12-01

    Self-locomotion is central to animal behaviour and survival. It is generally analysed by focusing on preferred speeds and gaits under particular biological and physical constraints. In the present paper we focus instead on the maximum speed and we study its order-of-magnitude scaling with body size, from bacteria to the largest terrestrial and aquatic organisms. Using data for about 460 species of various taxonomic groups, we find a maximum relative speed of the order of magnitude of ten body lengths per second over a 1020-fold mass range of running and swimming animals. This result implies a locomotor time scale of the order of one tenth of second, virtually independent on body size, anatomy and locomotion style, whose ubiquity requires an explanation building on basic properties of motile organisms. From first-principle estimates, we relate this generic time scale to other basic biological properties, using in particular the recent generalisation of the muscle specific tension to molecular motors. Finally, we go a step further by relating this time scale to still more basic quantities, as environmental conditions at Earth in addition to fundamental physical and chemical constants.