WorldWideScience

Sample records for acoustic detection

  1. Acoustic detection

    International Nuclear Information System (INIS)

    Riccobene, Giorgio

    2008-01-01

    The proposal of acoustic neutrino detection is living a renaissance: the interest in ultra high energy neutrino detection, the fast improvements of deep sea technology and the availability of large deep sea research infrastructures are the three main ingredients to explain the new interest in this technique. The status of simulation work, medium studies, sensor developments and first results from test experimental setups are presented.

  2. Method for acoustic signal detection

    International Nuclear Information System (INIS)

    Blalock, S.E.

    1980-01-01

    The disclosure relates to a method and apparatus for acoustic signal detection, adapted for use in acoustic velocity well logging to measure the difference in transit times of an acoustic signal between a transmitter and two or more receivers. In a preferred embodiment of the present invention two timing measurements of the signal arriving at each of two receivers may be made by activating zero crossing detectors at the arrival of the first negative and first positive half-cycles at each receiver. A transit time is calculated from the zero crossing times following the first negative half-cycle. This first transit time may be checked for accuracy by comparing the first transit time with a second transit time calculated from zero crossing times following the first positive half-cycles, by comparing the first transit time to a previously measured transit time and/or by detecting the order of arrival of the negative and positive half-cycles to determine whether the half-cycles have been detected out of sequence at either receiver. Should the first transit time be determined to be inaccurate, the previously measured transit time or the second transit time may be substituted therefor

  3. Golden Gate and Pt. Reyes Acoustic Detections

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detections of acoustic tagged fish from two general locations: Golden Gate (east and west line) and Pt. Reyes. Several Vemco 69khz acoustic...

  4. Acoustic Particle Detection with the ANTARES Detector

    Directory of Open Access Journals (Sweden)

    M. Neff

    2010-01-01

    Full Text Available The (Antares Modules for Acoustic Detection Under the Sea AMADEUS system within the (Astronomy with a Neutrino Telescope and Abyss environmental RESsearch ANTARES neutrino telescope is designed to investigate detection techniques for acoustic signals produced by particle cascades. While passing through a liquid a cascade deposits energy and produces a measurable pressure pulse. This can be used for the detection of neutrinos with energies exceeding 1018 eV. The AMADEUS setup consists of 36 hydrophones grouped in six local clusters measuring about one cubic meter each. This article focuses on acoustic particle detection, the hardware of the AMADEUS detector and techniques used for acoustic signal processing.

  5. Acoustic Particle Detection with the ANTARES Detector

    Directory of Open Access Journals (Sweden)

    Richardt C

    2010-01-01

    Full Text Available The (Antares Modules for Acoustic Detection Under the Sea AMADEUS system within the (Astronomy with a Neutrino Telescope and Abyss environmental RESsearch ANTARES neutrino telescope is designed to investigate detection techniques for acoustic signals produced by particle cascades. While passing through a liquid a cascade deposits energy and produces a measurable pressure pulse. This can be used for the detection of neutrinos with energies exceeding  eV. The AMADEUS setup consists of 36 hydrophones grouped in six local clusters measuring about one cubic meter each. This article focuses on acoustic particle detection, the hardware of the AMADEUS detector and techniques used for acoustic signal processing.

  6. The deep sea Acoustic Detection system AMADEUS

    International Nuclear Information System (INIS)

    Naumann, Christopher Lindsay

    2008-01-01

    As a part of the ANTARES neutrino telescope, the AMADEUS (ANTARES Modules for Acoustic Detection Under the Sea) system is an array of acoustical sensors designed to investigate the possibilities of acoustic detection of ultra-high energy neutrinos in the deep sea. The complete system will comprise a total of 36 acoustic sensors in six clusters on two of the ANTARES detector lines. With an inter-sensor spacing of about one metre inside the clusters and between 15 and 340 metres between the different clusters, it will cover a wide range of distances as will as provide a considerable lever arm for point source triangulation. Three of these clusters have already been deployed in 2007 and have been in operation since, currently yielding around 2GB of acoustic data per day. The remaining three clusters are scheduled to be deployed in May 2008 together with the final ANTARES detector line. Apart from proving the feasibility of operating an acoustic detection system in the deep sea, the main aim of this project is an in-depth survey of both the acoustic properties of the sea water and the acoustic background present at the detector site. It will also serve as a platform for the development and refinement of triggering, filtering and reconstruction algorithms for acoustic particle detection. In this presentation, a description of the acoustic sensor and read-out system is given, together with examples for the reconstruction and evaluation of the acoustic data.

  7. Feature selection for multimodal: acoustic Event detection

    OpenAIRE

    Butko, Taras

    2011-01-01

    Acoustic Event Detection  The detection of the Acoustic Events (AEs) naturally produced in a meeting room may help to describe the human and social activity. The automatic description of interactions between humans and environment can be useful for providing: implicit assistance to the people inside the room, context-aware and content-aware information requiring a minimum of human attention or interruptions, support for high-level analysis of the underlying acoustic scene, etc. On the othe...

  8. Acoustic resonance for nonmetallic mine detection

    Energy Technology Data Exchange (ETDEWEB)

    Kercel, S.W.

    1998-04-01

    The feasibility of acoustic resonance for detection of plastic mines was investigated by researchers at the Oak Ridge National Laboratory`s Instrumentation and Controls Division under an internally funded program. The data reported in this paper suggest that acoustic resonance is not a practical method for mine detection. Representative small plastic anti-personnel mines were tested, and were found to not exhibit detectable acoustic resonances. Also, non-metal objects known to have strong acoustic resonances were tested with a variety of excitation techniques, and no practical non-contact method of exciting a consistently detectable resonance in a buried object was discovered. Some of the experimental data developed in this work may be useful to other researchers seeking a method to detect buried plastic mines. A number of excitation methods and their pitfalls are discussed. Excitation methods that were investigated include swept acoustic, chopped acoustic, wavelet acoustic, and mechanical shaking. Under very contrived conditions, a weak response that could be attributed to acoustic resonance was observed, but it does not appear to be practical as a mine detection feature. Transfer properties of soil were investigated. Impulse responses of several representative plastic mines were investigated. Acoustic leakage coupling, and its implications as a disruptive mechanism were investigated.

  9. Acoustic leak detection and ultrasonic crack detection

    International Nuclear Information System (INIS)

    Kupperman, D.S.; Claytor, T.N.; Groenwald, R.

    1983-10-01

    A program is under way to assess the effectiveness of current and proposed techniques for acoustic leak detection (ALD) in reactor coolant systems. An ALD facility has been constructed and tests have begun on five laboratory-grown cracks (three fatigue and two thermal-fatigue and two field-induced IGSCC specimens. After ultrasonic testing revealed cracks in the Georgia Power Co. HATCH-1 BWR recirculation header, the utility installed an ALD system. Data from HATCH-1 have given an indication of the background noise level at a BWR recirculation header sweepolet weld. The HATCH leak detection system was tested to determine the sensitivity and dynamic range. Other background data have been acquired at the Watts Bar Nuclear Reactor in Tennessee. An ANL waveguide system, including transducer and electronics, was installed and tested on an accumulator safety injection pipe. The possibility of using ultrasonic wave scattering patterns to discriminate between IGSCCs and geometric reflectors has been explored. Thirteen reflectors (field IGSCCs, graphite wool IGSCCs, weld roots, and slits) were examined. Work with cast stainless steel (SS) included sound velocity and attenuation in isotropic and anisotropic cast SS. Reducing anisotropy does not help reduce attenuation in large-grained material. Large artificial flaws (e.g., a 1-cm-deep notch with a 4-cm path) could not be detected in isotropic centrifugally cast SS (1 to 2-mm grains) by longitudinal or shear waves at frequencies of 1 MHz or greater, but could be detected with 0.5-MHz shear waves. 13 figures

  10. Acoustic leak detection of LMFBR steam generator

    International Nuclear Information System (INIS)

    Kumagai, Hiromichi; Yoshida, Kazuo

    1993-01-01

    The development of a water leak detector with short response time for LMFBR steam generators is required to prevent the failure propagation caused by the sodium-water reaction and to maintain structural safety in steam generators. The development of an acoustic leak detector assuring short response time has attracted. The purpose of this paper is to confirm the basic detection feasibility of the active acoustic leak detector, and to investigate the leak detection method by erasing the background noise by spectrum analysis of the passive acoustic leak detector. From a comparison of the leak detection sensitivity of the active and the passive method, the active method is not influenced remarkably by the background noise, and it has possibility to detect microleakage with short response time. We anticipate a practical application of the active method in the future. (author)

  11. Humanitarian mine detection by acoustic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Kercel, S.W.

    1998-03-01

    The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical

  12. Mobile platform for acoustic mine detection applications

    Science.gov (United States)

    Libbey, Brad; Fenneman, Douglas; Burns, Brian

    2005-06-01

    Researchers in academia have successfully demonstrated acoustic landmine detection techniques. These typically employ acoustic or seismic sources to induce vibration in the mine/soil system, and use vibration sensors such as laser vibrometers or geophones to measure the resultant surface motion. These techniques exploit the unique mechanical properties of landmines to discriminate the vibration response of a buried mine from an off-target measurement. The Army requires the ability to rapidly and reliably scan an area for landmines and is developing a mobile platform at NVESD to meet this requirement. The platform represents an initial step toward the implementation of acoustic mine detection technology on a representative field vehicle. The effort relies heavily on the acoustic mine detection cart system developed by researchers at the University of Mississippi and Planning Systems, Inc. The NVESD platform consists of a John Deere E-gator configured with a robotic control system to accurately position the vehicle. In its present design, the E-gator has been outfitted with an array of laser vibrometers and a bank of loudspeakers. Care has been taken to ensure that the vehicle"s mounting hardware and data acquisition algorithms are sufficiently robust to accommodate the implementation of other sensor modalities. A thorough discussion of the mobile platform from its inception to its present configuration will be provided. Specific topics to be addressed include the vehicle"s control and data acquisition systems. Preliminary results from acoustic mine detection experiments will also be presented.

  13. Target detectability in acoustic elastography.

    Science.gov (United States)

    Bilgen, M

    1999-01-01

    The clinically relevant task of visually detecting low contrast targets in noisy strain images estimated from ultrasonic signals is studied. Detectability is measured quantitatively using contrast-to-noise ratio (CNR) analysis. Contrast in strain images is generated by a complex interaction among the soft tissue elasticity shear modulus distribution, target shape and location in the stress field, and external boundary conditions. Although a large strain variation is preferred for enhancing the contrast, this also increases the signal-dependent noise in strain estimates in a nonlinear fashion. Therefore, understanding the tradeoffs between contrast and noise is necessary for improving the diagnostic performance of strain imaging. In this paper, targets with slab, cylindrical, and spherical geometries are studied. Strains in the target and background and the precision of their estimates are described in terms of the corresponding shear modulus values for each geometry. These results are then incorporated into the CNR expression to investigate the changes in target detectability with the variation of shear modulus in the target and the ultrasonic signal parameters (echo signal-to-noise ratio and inverse fractional bandwidth) as well as the signal processing variables (time-bandwidth product and fractional window overlap).

  14. Acoustic leak detection development in the USA

    International Nuclear Information System (INIS)

    Greene, D.A.; Malovrh, J.W.; Magee, P.M.

    1984-01-01

    Acoustic monitoring systems that detect and locate a leak of water/steam from a defective tube in an LMFBR steam generator have been developed in the United States. A low frequency (approx. 10 KHz) system was developed by General Electric, and a high frequency (200 to 300 KHz) system by Rockwell International with support from Argonne National Laboratory. A comprehensive base technology program provided absolute signal amplitudes, background noise amplitudes, and signal source-to-detector transfer functions. Field tests of these systems demonstrated an ability to detect and locate simulated leaks under operating and quiescent conditions in an LMFBR steam generator. (author)

  15. Nonlinear acoustic techniques for landmine detection

    Science.gov (United States)

    Korman, Murray S.; Sabatier, James M.

    2004-12-01

    Measurements of the top surface vibration of a buried (inert) VS 2.2 anti-tank plastic landmine reveal significant resonances in the frequency range between 80 and 650 Hz. Resonances from measurements of the normal component of the acoustically induced soil surface particle velocity (due to sufficient acoustic-to-seismic coupling) have been used in detection schemes. Since the interface between the top plate and the soil responds nonlinearly to pressure fluctuations, characteristics of landmines, the soil, and the interface are rich in nonlinear physics and allow for a method of buried landmine detection not previously exploited. Tuning curve experiments (revealing ``softening'' and a back-bone curve linear in particle velocity amplitude versus frequency) help characterize the nonlinear resonant behavior of the soil-landmine oscillator. The results appear to exhibit the characteristics of nonlinear mesoscopic elastic behavior, which is explored. When two primary waves f1 and f2 drive the soil over the mine near resonance, a rich spectrum of nonlinearly generated tones is measured with a geophone on the surface over the buried landmine in agreement with Donskoy [SPIE Proc. 3392, 221-217 (1998); 3710, 239-246 (1999)]. In profiling, particular nonlinear tonals can improve the contrast ratio compared to using either primary tone in the spectrum. .

  16. A Correlated Active Acoustic Leak Detection in a SFR Steam Generator

    International Nuclear Information System (INIS)

    Kim, Tae Joon; Jeong, Ji Young; Kim, Jong Man; Kim, Byung Ho; Kim, Yong Il

    2009-01-01

    The methods of acoustic leak detection are active acoustic leak detection and passive acoustic leak detection. The methods for passive acoustic leak detection are already established, but because our goal is development of passive acoustic leak detection for detecting a leakage range of small and micro leak rates, it is difficult detecting a leak in steam generator using this developed passive acoustic leak detection. Thus the acoustic leak detection system is required to be able to detect wide range of water leaks. From this view point we need to develop an active acoustic leak detection technology to be able to detect intermediate leak rates

  17. Structural Acoustic UXO Detection and Identification in Marine Environments

    Science.gov (United States)

    2016-05-01

    high performance structural acoustic (SA) feature-based underwater sonar technology that can detect and localize buried (and proud) targets and...MR2103), we demonstrated the structural acoustic technology with an autonomous underwater vehicle (AUV) - based SA sonar successfully detecting UXO...We examined the acoustic color maps visually for the presence of a frequency/x position (aspect angle) feature that we had seen earlier in laboratory

  18. Acoustic leak detection in piping systems, 4

    International Nuclear Information System (INIS)

    Kitajima, Akira; Naohara, Nobuyuki; Aihara, Akihiko

    1983-01-01

    To monitor a high-pressure piping of nuclear power plants, a possibility of acoustic leak detection method has been experimentally studied in practical field tests and laboratory tests. Characteristics of background noise in field test and the results of experiment are summarized as follows: (1) The level of background noise in primary loop (PWR) was almost constant under actual plant operation. But it is possible that it rises at the condition of the pressure in primary loop. (2) Based on many experience of laboratory tests and practical field tests. The leak monitoring system for practical field was designed and developed. To improve the reliability, a judgment of leak on this system is used three factors of noise level, duration time of phenomena and frequency spectrum of noise signal emitted from the leak point. (author)

  19. The RAP experiment Acoustic Detection of Particles

    CERN Document Server

    Bassan, M; Cavallari, G; Coccia, E; D'Antonio, S; Delle Monache; Di Gioacchino, D; Fafone, V; Ligi, C; Marini, A; Mazzitelli, G; Modestino, G; Pizzella, G; Quintieri, L; Roccella, S; Rocchi, A; Ronga, F; Tripodi, P; Valente, F

    2007-01-01

    The RAP experiment is based on the acoustic detection of high energy particles by cylindrical bars. In fact, the interacting particles warm up the material around their track causing a local thermal expansion that, being prevented by the rest of the material, causes a local impulse of pressure. Consequently the bar starts to vibrate and the amplitude of the oscillation is proportional to the energy released. The RAP experiment has the aim to investigate the mechanical excitation of cylindrical bars caused by impinging particles depending on the conducting status of the material of which the detector is made. In particular physical phenomena related to the superconductivity state could be involved in such a way to enhance the conversion efficiency of the particle energy into mechanical vibrations. Essentially, two materials have been tested: aluminum alloy (Al5056) and niobium. In this report we report the measurements obtained for a niobium bar from room temperature down to 4K, below the transition temperatur...

  20. Acoustic change detection algorithm using an FM radio

    Science.gov (United States)

    Goldman, Geoffrey H.; Wolfe, Owen

    2012-06-01

    The U.S. Army is interested in developing low-cost, low-power, non-line-of-sight sensors for monitoring human activity. One modality that is often overlooked is active acoustics using sources of opportunity such as speech or music. Active acoustics can be used to detect human activity by generating acoustic images of an area at different times, then testing for changes among the imagery. A change detection algorithm was developed to detect physical changes in a building, such as a door changing positions or a large box being moved using acoustics sources of opportunity. The algorithm is based on cross correlating the acoustic signal measured from two microphones. The performance of the algorithm was shown using data generated with a hand-held FM radio as a sound source and two microphones. The algorithm could detect a door being opened in a hallway.

  1. The RAP experiment: Acoustic Detection of Particles

    Science.gov (United States)

    Bassan, M.; Buonomo, B.; Cavallari, G.; Coccia, E.; D'Antonio, S.; Delle Monache, G.; Di Gioacchino, D.; Fafone, V.; Ligi, C.; Marini, A.; Mazzitelli, G.; Modestino, G.; Pizzella, G.; Quintieri, L.; Roccella, S.; Rocchi, A.; Ronga, F.; Tripodi, P.; Valente, P.

    2007-10-01

    The RAP experiment is based on the acoustic detection of high energy particles by cylindrical bars. In fact, the interacting particles warm up the material around their track causing a local thermal expansion that, being prevented by the rest of the material, causes a local impulse of pressure. Consequently the bar starts to vibrate and the amplitude of the oscillation is proportional to the energy released. The RAP experiment has the aim to investigate the mechanical excitation of cylindrical bars caused by impinging particles depending on the conducting status of the material of which the detector is made. In particular physical phenomena related to the superconductivity state could be involved in such a way to enhance the conversion efficiency of the particle energy into mechanical vibrations. Essentially, two materials have been tested: aluminum alloy (Al5056) and niobium. In this report we report the measurements obtained for a niobium bar from room temperature down to 4K, below the transition temperature, and those obtained for an Al5056 bar above the transition (from 4 to 293 K).

  2. Recent experiments on acoustic leak detection

    International Nuclear Information System (INIS)

    Voss, J.; Arnaoutis, N.

    1984-01-01

    In the ASB-sodium loop a series of injection experiments with water, helium, argon and nitrogen was performed. The aim of these tests was to get: a comparison of the acoustic signals, generated by water and gas injections with regard to intensity and frequency content; an experimental basis for the design of an acoustic calibration source. The experimental set-up, the variation parameters and first results will be discussed. The principal design of an acoustic calibration source and its range of application will be given. (author)

  3. Acoustic Inverse Scattering for Breast Cancer Microcalcification Detection

    Science.gov (United States)

    2009-09-01

    Acoustic Inverse Scattering for Breast Cancer Microcalcification Detection 5b. GRANT NUMBER W81XWH-07-1-0640 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S... Microcalcification detection is the hallmark of mammography as a breast cancer screening modality. For technical reasons, ultrasonic detection of all... Cancer Microcalcification Detection PRINCIPAL INVESTIGATOR: Matthew A. Lewis, Ph.D. CONTRACTING ORGANIZATION: University of Texas

  4. Acoustic Detection from Aerial Balloon Platform

    National Research Council Canada - National Science Library

    Reiff, C; Pham, T; Scanlon, M; Noble, J; Van Landuyt, A; Petek, J; Ratches, J

    2004-01-01

    ... such as unmanned aerial vehicles (UAVs) and balloons. Our most immediate collaboration focuses on the use of acoustic sensors on small balloons and/or aerostats at several elevations and on the ground with the primary goals...

  5. Measurement of the Laser induced thermo-acoustic effect for acoustic neutrino detection

    Energy Technology Data Exchange (ETDEWEB)

    Heinen, Dirk; Laihem, Karim; Paul, Larissa; Scheel, Maximilian; Wiebusch, Christopher [III. Physikalisches Institut, RWTH Aachen (Germany); Collaboration: IceCube-Collaboration

    2012-07-01

    Future neutrino telescopes with the aim to explore the extreme high energy region (above 10{sup 18} eV) require 2-3 orders of magnitude larger effective volumes compared to current optical detectors (IceCube 1 km{sup 3}). One possible approach is the acoustic detection of the thermo-acoustic pressure wave generated by hadronic cascades in neutrino interactions. A major goal of the Aachen Acoustic Laboratory (AAL) is to study the thermo-acoustic effect under laboratory conditions and to develop appropriate detection methods. Central element is a large volume (3 m{sup 3}) of ice or water in which sensor and emitter elements are deployed. Thermo-acoustic signals are generated by a pulsed laser beam injected into the volume. In this talk we present the experimental setup and measurements of the laser induced thermo-acoustic sound waves. In addition to these laboratory measurements an outlook on future in-situ measurements of acoustic signals in ice will be given.

  6. Acoustic Helicopter and FW Aircraft Detection and Classification

    NARCIS (Netherlands)

    Koersel, A.C. van

    2001-01-01

    The possibility to detect the passage of aircraft (either propeller or jet) with one or more mechanical wave sensors (acoustic or seismic) is investigated. An existing algorithm-sensor demonstator can detect and classify helicopter targets. In its current form it is developed to reject other

  7. Passive acoustic detection of deep-diving beaked whales

    DEFF Research Database (Denmark)

    Zimmer, W.M.X.; Harwood, J.; Tyack, P.L.

    2008-01-01

    Beaked whales can remain submerged for an hour or more and are difficult to sight when they come to the surface to breathe. Passive acoustic detection (PAD) not only complements traditional visual-based methods for detecting these species but also can be more effective because beaked whales produ...

  8. Background Studies for Acoustic Neutrino Detection at the South Pole

    Science.gov (United States)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; hide

    2012-01-01

    The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method. to measure the flux of cosmogenic neutrinos expected on Earth. The energy threshold for this process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS). deployed in the upper part of four boreholes of the IceCube Neutrino Observatory, has monitored the noise in Antarctic ice at the geographic South Pole for more than two years down to 500 m depth. The noise is very stable and Gaussian distributed, Lacking an in situ calibration up to now, laboratory measurements have been used to estimate the absolute noise level in the 10-50 kHz frequency range to be smaller than 20 mPa. Using a threshold trigger. sensors of the South Pole Acoustic Test Setup registered acoustic events in the IceCube detector volume and its vicinity. Acoustic signals from refreezing IceCube holes and from anthropogenic sources have been used to test the localization of acoustic events. An upper limit on the neutrino flux at energies E(sub v) > 10(exp 11) GeV is derived from acoustic data taken over eight months.

  9. Acoustic Aspects of Photoacoustic Signal Generation and Detection in Gases

    Science.gov (United States)

    Miklós, A.

    2015-09-01

    In this paper photoacoustic signal generation and detection in gases is investigated and discussed from the standpoint of acoustics. Four topics are considered: the effect of the absorption-desorption process of modulated and pulsed light on the heat power density released in the gas; the generation of the primary sound by the released heat in an unbounded medium; the excitation of an acoustic resonator by the primary sound; and finally, the generation of the measurable PA signal by a microphone. When light is absorbed by a molecule and the excess energy is relaxed by collisions with the surrounding molecules, the average kinetic energy, thus also the temperature of an ensemble of molecules (called "particle" in acoustics) will increase. In other words heat energy is added to the energy of the particle. The rate of the energy transfer is characterized by the heat power density. A simple two-level model of absorption-desorption is applied for describing the heat power generation process for modulated and pulsed illumination. Sound generation by a laser beam in an unbounded medium is discussed by means of the Green's function technique. It is shown that the duration of the generated sound pulse depends mostly on beam geometry. A photoacoustic signal is mostly detected in a photoacoustic cell composed of acoustic resonators, buffers, filters, etc. It is not easy to interpret the measured PA signal in such a complicated acoustic system. The acoustic response of a PA detector to different kinds of excitations (modulated cw, pulsed, periodic pulse train) is discussed. It is shown that acoustic resonators respond very differently to modulated cw excitation and to excitation by a pulse train. The microphone for detecting the PA signal is also a part of the acoustic system; its properties have to be taken into account by the design of a PA detector. The moving membrane of the microphone absorbs acoustic energy; thus, it may influence the resonance frequency and

  10. Autonomous acoustic/seismic networks for intrusion detection and assessment

    International Nuclear Information System (INIS)

    Swanson, D.C.; Kurtz, P.H.

    1995-01-01

    Passive acoustic and seismic sensors have the unique capability for inexpensive non-line-of-sight (NLOS) detection and identification of vehicle movements as well as human and machine activity. By networking multiple sensor sites, one can use on-site processing to minimize internode communications for data fusion to localize the target of interest. Since all acoustic and seismic sources have characteristic directivity responses to their respective noise signatures, the network also offers the ability to observe and identify these characteristics. However, in many perimeter defense situations, a simple detection is all that's really needed. Therefore, the intelligent sensor processing goal is to reduce the false alarm rate in the presence of significant changes in background noise and the environment. The authors have developed a generic hardware platform for acoustic/seismic detection and environmental characterization. They have also developed adaptive models for predicting target detectability in a dynamic environment for performance prediction of the sensor networks. Initial performance tests of the hardware are very encouraging and the authors expect acoustic/seismic sensor networks and the environmental models to have a wide variety uses in surveillance and intrusion detection

  11. Diesel Engine Valve Clearance Detection Using Acoustic Emission

    Directory of Open Access Journals (Sweden)

    Fathi Elamin

    2010-01-01

    Full Text Available This paper investigated, using experimental method, the suitability of acoustic emission (AE technique for the condition monitoring of diesel engine valve faults. The clearance fault was adjusted experimentally in an exhaust valve and successfully detected and diagnosed in a Ford FSD 425 four-cylinder, four-stroke, in-line OHV, direct injection diesel engine. The effect of faulty exhaust valve clearance on engine performance was monitored and the difference between the healthy and faulty engine was observed from the recorded AE signals. The measured results from this technique show that using only time domain and frequency domain analysis of acoustic emission signals can give a superior measure of engine condition. This concludes that acoustic emission is a powerful and reliable method of detection and diagnosis of the faults in diesel engines and this is considered to be a unique approach to condition monitoring of valve performance.

  12. Profiling of Molecular Interactions in Real Time using Acoustic Detection

    Science.gov (United States)

    Godber, Benjamin; Frogley, Mark; Rehak, Marian; Sleptsov, Alexander; Thompson, Kevin S.J.; Uludag, Yildiz; Cooper, Matthew A.

    2007-01-01

    Acoustic sensors that exploit resonating quartz crystals to directly detect the binding of an analyte to a receptor are finding increasing utility in the quantification of clinically-relevant analytes. We have developed a novel acoustic detection technology, which we term Resonant Acoustic Profiling (RAP™). This technology builds on the fundamental basics of the “quartz crystal microbalance” or “QCM” with several key additional features including two- or four-channel automated sample delivery, in-line referencing and microfluidic sensor ‘cassettes’ that are pre-coated with easy-to-use surface chemistries. Example applications are described for the quantification of myoglobin concentration and its interaction kinetics, and for the ranking of enzyme-cofactor specificities. PMID:17129723

  13. Tadarida: A Toolbox for Animal Detection on Acoustic Recordings

    Directory of Open Access Journals (Sweden)

    Yves Bas

    2017-02-01

    Full Text Available Passive Acoustic Monitoring (PAM recently extended to a very wide range of animals, but no available open software has been sufficiently generic to automatically treat several taxonomic groups. Here we present Tadarida, a software toolbox allowing for the detection and labelling of recorded sound events, and to classify any new acoustic data into known classes. It is made up of three modules handling Detection, Labelling and Classification and running on either Linux or Windows. This development resulted in the first open software (1 allowing generic sound event detection (multi-taxa, (2 providing graphical sound labelling at a single-instance level and (3 covering the whole process from sound detection to classification. This generic and modular design opens numerous reuse opportunities among (bioacoustics researchers, especially for those managing and/or developing PAM schemes. The whole toolbox is openly developed in C++ (Detection and Labelling and R (Classification and stored at https://github.com/YvesBas.

  14. Evaluation of acoustic tomography for tree decay detection

    Science.gov (United States)

    Shanquing Liang; Xiping Wang; Janice Wiedenbeck; Zhiyong Cai; Feng Fu

    2008-01-01

    In this study, the acoustic tomography technique was used to detect internal decay in high value black cherry (Prunus seratina) trees. Two-dimensional images of the cross sections of the tree samples were constructed using PiCUS Q70 software. The trees were felled following the field test, and a disc from each testing elevation was subsequently cut...

  15. Acoustic tomography for decay detection in black cherry trees

    Science.gov (United States)

    Xiping Wang; Jan Wiedenbeck; Shanqing Liang

    2009-01-01

    This study investigated the potential of using acoustic tomography for detecting internal decay in high-value hardwood trees in the forest. Twelve black cherry (Prunus serotina) trees that had a wide range of physical characteristics were tested in a stand of second-growth hardwoods in Kane, PA, using a PiCUS Sonic Tomograph tool. The trees were felled after the field...

  16. Development of acoustic leak detection system in PNC

    International Nuclear Information System (INIS)

    Tanabe, H.; Kuroha, M.

    1990-01-01

    The development of an acoustic leak detector is under way at PNC as a detection system that has potential of quick response and high reliability for larger steam generators of future LMFBR plants. The studies have two aspects, i.e., an acoustic wave analysis in various sodium-water reactions and a background noise (BGN) analysis in a sodium-heated 50MWt steam generator (50MWGS). In the former analysis, wave profiles of the sodium-water reaction sound were analyzed and compared with those of inert gas injection sound. The comparison revealed that there were no wave profiles specific to a sodium-water reaction sound. The latter clarified that major acoustic sources in the steam generator were sodium flow and steam generation/flow and that the water leak rate at which a noise level was comparable with that of the background noise was about 0.5 g/sec. in the evaporator of 50MWSG. The estimation of acceleration levels of BGN and leak sounds in other plants reveals that an intermediate leak is detectable in the Monju evaporator with a present acoustic detection system. (author). 2 refs, 9 figs

  17. Factors Affecting Detection Probability of Acoustic Tags in Coral Reefs

    KAUST Repository

    Bermudez, Edgar F.

    2012-05-01

    Acoustic telemetry is an important tool for studying the movement patterns, behaviour, and site fidelity of marine organisms; however, its application is challenged in coral reef environments where complex topography and intense environmental noise interferes with acoustic signals, and there has been less study. Therefore, it is particularly critical in coral reef telemetry studies to first conduct a long-term range test, a tool that provides informa- tion on the variability and periodicity of the transmitter detection range and the detection probability. A one-month range test of a coded telemetric system was conducted prior to a large-scale tagging project investigating the movement of approximately 400 fishes from 30 species on offshore coral reefs in the central Red Sea. During this range test we determined the effect of the following factors on transmitter detection efficiency: distance from receiver, time of day, depth, wind, current, moon-phase and temperature. The experiment showed that biological noise is likely to be responsible for a diel pattern of -on average- twice as many detections during the day as during the night. Biological noise appears to be the most important noise source in coral reefs overwhelming the effect of wind-driven noise, which is important in other studies. Detection probability is also heavily influenced by the location of the acoustic sensor within the reef structure. Understanding the effect of environmental factors on transmitter detection probability allowed us to design a more effective receiver array for the large-scale tagging study.

  18. Acoustic source separation for the detection of coronary artery sounds.

    Science.gov (United States)

    Cooper, Daniel B; Roan, Michael J; Vlachos, Pavlos P

    2011-12-01

    Coronary artery disease (CAD) is the leading cause of death in the United States, being responsible for more than 20% of all deaths in the country. This is in large part due to the difficulty of diagnostic screening for CAD. Phonoangiography seeks to detect CAD via the acoustic signature associated with turbulent flow near an abnormally constricted, or stenosed, region. However, the usefulness of the technique is severely hindered by the low strength of the CAD signal compared to the background noise within the chest. In this work, acoustic finite element analysis (FEA) was performed on physiologically accurate chest geometries to demonstrate the feasibility of an original acoustic source separation methodology for isolating coronary sounds. This approach is based upon pseudoinversion of mixing matrices determined through a combination of experiment and computation. This allows calculation of the sound emitted by the coronary arteries based upon measurements of the acoustic velocity on the chest surface. This work demonstrates the feasibility of such a technique computationally and examines the vulnerability of the proposed approach to measurement errors. © 2011 Acoustical Society of America

  19. Early forest fire detection using radio-acoustic sounding system.

    Science.gov (United States)

    Sahin, Yasar Guneri; Ince, Turker

    2009-01-01

    Automated early fire detection systems have recently received a significant amount of attention due to their importance in protecting the global environment. Some emergent technologies such as ground-based, satellite-based remote sensing and distributed sensor networks systems have been used to detect forest fires in the early stages. In this study, a radio-acoustic sounding system with fine space and time resolution capabilities for continuous monitoring and early detection of forest fires is proposed. Simulations show that remote thermal mapping of a particular forest region by the proposed system could be a potential solution to the problem of early detection of forest fires.

  20. Steam generator leak detection using acoustic method

    International Nuclear Information System (INIS)

    Goluchko, V.V.; Sokolov, B.M.; Bulanov, A.N.

    1982-05-01

    The main requirements to meet by a device for leak detection in sodium - water steam generators are determined. The potentialities of instrumentation designed based on the developed requirements have been tested using a model of a 550 kw steam generator [fr

  1. ACOUSTIC DETECTING AND LOCATING GAS PIPE LINE INFRINGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-12-01

    The extensive network of high-pressure natural gas transmission pipelines covering the United States provides an important infrastructure for our energy independence. Early detection of pipeline leaks and infringements by construction equipment, resulting in corrosion fractures, presents an important aspect of our national security policy. The National Energy Technology Laboratory Strategic Center for Natural Gas (SCVG) is and has been funding research on various applicable techniques. The WVU research team has focused on monitoring pipeline background acoustic signals generated and transmitted by gas flowing through the gas inside the pipeline. In case of a pipeline infringement, any mechanical impact on the pipe wall, or escape of high-pressure gas, generates acoustic signals traveling both up and down stream through the gas. Sudden changes in flow noise are detectable with a Portable Acoustic Monitoring Package (PAMP), developed under this contract. It incorporates a pressure compensating microphone and a signal- recording device. Direct access to the gas inside the line is obtained by mounting such a PAMP, with a 1/2 inch NPT connection, to a pipeline pressure port found near most shut-off valves. An FFT of the recorded signal subtracted by that of the background noise recorded one-second earlier appears to sufficiently isolate the infringement signal to allow source interpretation. Using cell phones for data downloading might allow a network of such 1000-psi rated PAMP's to acoustically monitor a pipeline system and be trained by neural network software to positively identify and locate any pipeline infringement.

  2. ACOUSTIC DETECTING AND LOCATING GAS PIPE LINE INFRINGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-10-31

    The extensive network of high-pressure natural gas transmission pipelines covering the United States provides an important infrastructure for our energy independence. Early detection of pipeline leaks and infringements by construction equipment, resulting in corrosion fractures, presents an important aspect of our national security policy. The National Energy Technology Laboratory Strategic Center for Natural Gas (SCVG) is and has been funding research on various applicable techniques. The WVU research team has focused on monitoring pipeline background acoustic signals generated and transmitted by gas flowing through the gas inside the pipeline. In case of a pipeline infringement, any mechanical impact on the pipe wall, or escape of high-pressure gas, generates acoustic signals traveling both up and down stream through the gas. Sudden changes in flow noise are detectable with a Portable Acoustic Monitoring Package (PAMP), developed under this contract. It incorporates a pressure compensating microphone and a signal- recording device. Direct access to the gas inside the line is obtained by mounting such a PAMP, with a 1/2 inch NPT connection, to a pipeline pressure port found near most shut-off valves. An FFT of the recorded signal subtracted by that of the background noise recorded one-second earlier appears to sufficiently isolate the infringement signal to allow source interpretation. Using cell phones for data downloading might allow a network of such 1000-psi rated PAMP's to acoustically monitor a pipeline system and be trained by neural network software to positively identify and locate any pipeline infringement.

  3. Topography and biological noise determine acoustic detectability on coral reefs

    KAUST Repository

    Cagua, Edgar F.

    2013-08-19

    Acoustic telemetry is an increasingly common tool for studying the movement patterns, behavior and site fidelity of marine organisms, but to accurately interpret acoustic data, the variability, periodicity and range of detectability between acoustic tags and receivers must be understood. The relative and interactive effects of topography with biological and environmental noise have not been quantified on coral reefs. We conduct two long-term range tests (1- and 4-month duration) on two different reef types in the central Red Sea to determine the relative effect of distance, depth, topography, time of day, wind, lunar phase, sea surface temperature and thermocline on detection probability. Detectability, as expected, declines with increasing distance between tags and receivers, and we find average detection ranges of 530 and 120 m, using V16 and V13 tags, respectively, but the topography of the reef can significantly modify this relationship, reducing the range by ~70 %, even when tags and receivers are in line-of-sight. Analyses that assume a relationship between distance and detections must therefore be used with care. Nighttime detection range was consistently reduced in both locations, and detections varied by lunar phase in the 4-month test, suggesting a strong influence of biological noise (reducing detection probability up to 30 %), notably more influential than other environmental noises, including wind-driven noise, which is normally considered important in open-water environments. Analysis of detections should be corrected in consideration of the diel patterns we find, and range tests or sentinel tags should be used for more than 1 month to quantify potential changes due to lunar phase. Some studies assume that the most usual factor limiting detection range is weather-related noise; this cannot be extrapolated to coral reefs. © 2013 Springer-Verlag Berlin Heidelberg.

  4. Acoustic detection of ultra-high energy cascades in ice

    Energy Technology Data Exchange (ETDEWEB)

    Boeser, S.

    2006-12-08

    Current underwater optical neutrino telescopes are designed to detect neutrinos from astrophysical sources with energies in the TeV range. Due to the low fluxes and small cross sections, no high energy neutrinos of extraterrestrial origin have been observed so far. Only the Cherenkov neutrino detectors on the km{sup 3} scale that are currently under construction will have the necessary volume to observe these rare interactions. For the guaranteed source of neutrinos from interactions of the ultra-high energy cosmic at EeV energies rays with the ambient cosmic microwave background, event rates of only one per year are expected in these experiments. To measure the flux and verify the predicted cross sections of these cosmogenic neutrinos, an observed volume of the order of 100 km{sup 3} will be necessary, that will not be feasible with existing detection techniques. Alternative methods are required to build a detector on these scales. One promising idea is to record the acoustic waves generated in hadronic or electromagnetic cascades following the neutrino interaction. The higher amplitudes of the sonic signal and the large expected absorption length of sound favour South Polar ice instead of sea water as a medium. The prerequisites for an estimate of the potential of such a detector are suitable acoustic sensors, a verification of the model of thermo-acoustic sound generation and a determination of the acoustic properties of the ice. In a theoretical derivation the mechanism of thermo-elastic excitation of acoustic waves was shown to be equivalent for isotropic solids and liquids. Following a detailed analysis of the existing knowledge a simulation study of a hybrid optical-radio-acoustic detector has been performed. Ultrasonic sensors dedicated to in-ice application were developed and have been used to record acoustic signals from intense proton and laser beams in water and ice. With the obtained experience, the hitherto largest array of acoustic sensors and

  5. Acoustic detection of ultra-high energy cascades in ice

    International Nuclear Information System (INIS)

    Boeser, S.

    2006-01-01

    Current underwater optical neutrino telescopes are designed to detect neutrinos from astrophysical sources with energies in the TeV range. Due to the low fluxes and small cross sections, no high energy neutrinos of extraterrestrial origin have been observed so far. Only the Cherenkov neutrino detectors on the km 3 scale that are currently under construction will have the necessary volume to observe these rare interactions. For the guaranteed source of neutrinos from interactions of the ultra-high energy cosmic at EeV energies rays with the ambient cosmic microwave background, event rates of only one per year are expected in these experiments. To measure the flux and verify the predicted cross sections of these cosmogenic neutrinos, an observed volume of the order of 100 km 3 will be necessary, that will not be feasible with existing detection techniques. Alternative methods are required to build a detector on these scales. One promising idea is to record the acoustic waves generated in hadronic or electromagnetic cascades following the neutrino interaction. The higher amplitudes of the sonic signal and the large expected absorption length of sound favour South Polar ice instead of sea water as a medium. The prerequisites for an estimate of the potential of such a detector are suitable acoustic sensors, a verification of the model of thermo-acoustic sound generation and a determination of the acoustic properties of the ice. In a theoretical derivation the mechanism of thermo-elastic excitation of acoustic waves was shown to be equivalent for isotropic solids and liquids. Following a detailed analysis of the existing knowledge a simulation study of a hybrid optical-radio-acoustic detector has been performed. Ultrasonic sensors dedicated to in-ice application were developed and have been used to record acoustic signals from intense proton and laser beams in water and ice. With the obtained experience, the hitherto largest array of acoustic sensors and transmitters was

  6. Optimizing surface acoustic wave sensors for trace chemical detection

    Energy Technology Data Exchange (ETDEWEB)

    Frye, G.C.; Kottenstette, R.J.; Heller, E.J. [and others

    1997-06-01

    This paper describes several recent advances for fabricating coated surface acoustic wave (SAW) sensors for applications requiring trace chemical detection. Specifically, we have demonstrated that high surface area microporous oxides can provide 100-fold improvements in SAW sensor responses compared with more typical polymeric coatings. In addition, we fabricated GaAs SAW devices with frequencies up to 500 MHz to provide greater sensitivity and an ideal substrate for integration with high-frequency electronics.

  7. A hydrophone prototype for ultra high energy neutrino acoustic detection

    Energy Technology Data Exchange (ETDEWEB)

    Cotrufo, A. [University of Genoa, Department of Physics, Via Dodecaneso 33, I-16146 (Italy)], E-mail: cotrufo@ge.infn.it; Plotnikov, A.; Yershova, O. [GSI Helmholtz Centre for Heavy Ion Research, GmbH Planckstrasse1, 64291 Darmstadt (Germany); Anghinolfi, M.; Piombo, D. [INFN, University of Genoa, Department of Physics, Via Dodecaneso 33, I-16146 (Italy)

    2009-06-01

    The design of an air-backed fiber-optic hydrophone is presented. With respect to the previous models this prototype is optimized to provide a bandwidth sufficiently large to detect acoustic signals produced by high energy hadronic showers in water. In addiction to the geometrical configuration and to the choice of the materials, the preliminary results of the measured performances in air are presented.

  8. AMADEUS-The acoustic neutrino detection test system of the ANTARES deep-sea neutrino telescope

    NARCIS (Netherlands)

    Aguilar, J.A.; Al Samarai, I.; Albert, A.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Jesus, A.C.A.; Astraatmadja, T.; Aubert, J.J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-Cabo, M.; Bouwhuis, M.C.; Brown, A.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Carloganu, C.; Carminati, G.; Carr, J.; Cassano, B.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, P.; Chiarusi, T.; Sen, N.C.; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; De Bonis, G.; Decowski, M.P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J.P.; Escoffier, S.; Fehr, F.; Fiorello, C.; Flaminio, V.; Fritsch, U.; Fuda, J.L.; Gay, P.; Giacomelli, G.; Gomez-Gonzalez, J.P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Heijboer, A.J.; Heine, E.; Hello, Y.; Hernandez-Rey, J.J.; Herold, B.; Hossl, J.; De Jong, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Keller, P.; Kooijman, P.; Kopper, C.; Kouchneri, A.; Kretschmer, W.; Lahmann, R.; Lamare, P.; Lambard, G.; Larosa, G.; Laschinsky, H.; Le Provost, H.; Lefevre, D.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J.A.; Mazure, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Ostasch, R.; Palioselitis, D.; Pavalas, G.E.; Payre, P.; Petrovic, J.; Picot-Clemente, N.; Picq, C.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Radu, A.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Ruppi, M.; Russo, G.V.; Salesa, F.; Sapienza, P.; Schock, F.; Schuller, J.P.; Shanidze, R.; Simeone, F.; Spurio, M.; Steijger, J.J.M.; Stolarczyk, T.; Taiuti, M.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J.D.; Zuniga, J.

    2011-01-01

    The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic

  9. Simulation study of neutronic and acoustic methods of boiling detection

    International Nuclear Information System (INIS)

    Shimazaki, J.; Fujii, Y.; Shinohara, Y.; Araki, H.

    1981-01-01

    As a part of the work on the development of a diagnostic system for detecting anomalies in the core of a fast breeder reactor, a study is being made on the methods of detecting abnormal reactivity and coolant boiling on the basis computer simulation. The objective of the present simulation study is to obtain some basic information useful for developing sensitive method of signal processing suitable for boiling detection. Neutronic, acoustic and measurement noises as well as reactor kinetics and reactivity estimator are simulated on a hybrid computer and analyzed for various noise conditions using correlation, spectral and coherence analyses. It has been confirmed that the cross-spectral and coherence analyses between neutronic and acoustic signals are effective method for boiling detection provided that the void coefficient of reactivity is sufficiently large and that detection capability is slightly improved by using a discriminator of signal level before making spectral analysis. A simulated boiling detection experiment using a zero power thermal reactor is also planned in order to check the validity of computer simulation. (author)

  10. Acoustic Emission Beamforming for Detection and Localization of Damage

    Science.gov (United States)

    Rivey, Joshua Callen

    The aerospace industry is a constantly evolving field with corporate manufacturers continually utilizing innovative processes and materials. These materials include advanced metallics and composite systems. The exploration and implementation of new materials and structures has prompted the development of numerous structural health monitoring and nondestructive evaluation techniques for quality assurance purposes and pre- and in-service damage detection. Exploitation of acoustic emission sensors coupled with a beamforming technique provides the potential for creating an effective non-contact and non-invasive monitoring capability for assessing structural integrity. This investigation used an acoustic emission detection device that employs helical arrays of MEMS-based microphones around a high-definition optical camera to provide real-time non-contact monitoring of inspection specimens during testing. The study assessed the feasibility of the sound camera for use in structural health monitoring of composite specimens during tensile testing for detecting onset of damage in addition to nondestructive evaluation of aluminum inspection plates for visualizing stress wave propagation in structures. During composite material monitoring, the sound camera was able to accurately identify the onset and location of damage resulting from large amplitude acoustic feedback mechanisms such as fiber breakage. Damage resulting from smaller acoustic feedback events such as matrix failure was detected but not localized to the degree of accuracy of larger feedback events. Findings suggest that beamforming technology can provide effective non-contact and non-invasive inspection of composite materials, characterizing the onset and the location of damage in an efficient manner. With regards to the nondestructive evaluation of metallic plates, this remote sensing system allows us to record wave propagation events in situ via a single-shot measurement. This is a significant improvement over

  11. Acoustic sensors in the helmet detect voice and physiology

    Science.gov (United States)

    Scanlon, Michael V.

    2003-09-01

    The Army Research Laboratory has developed body-contacting acoustic sensors that detect diverse physiological sounds such as heartbeats and breaths, high quality speech, and activity. These sensors use an acoustic impedance-matching gel contained in a soft, compliant pad to enhance the body borne sounds, yet significantly repel airborne noises due to an acoustic impedance mismatch. The signals from such a sensor can be used as a microphone with embedded physiology, or a dedicated digital signal processor can process packetized data to separate physiological parameters from voice, and log parameter trends for performance surveillance. Acoustic sensors were placed inside soldier helmets to monitor voice, physiology, activity, and situational awareness clues such as bullet shockwaves from sniper activity and explosions. The sensors were also incorporated into firefighter breathing masks, neck and wrist straps, and other protective equipment. Heart rate, breath rate, blood pressure, voice and activity can be derived from these sensors (reports at www.arl.army.mil/acoustics). Having numerous sensors at various locations provides a means for array processing to reduce motion artifacts, calculate pulse transit time for passive blood pressure measurement, and the origin of blunt/penetrating traumas such as ballistic wounding. These types of sensors give us the ability to monitor soldiers and civilian emergency first-responders in demanding environments, and provide vital signs information to assess their health status and how that person is interacting with the environment and mission at hand. The Objective Force Warrior, Scorpion, Land Warrior, Warrior Medic, and other military and civilian programs can potentially benefit from these sensors.

  12. Non-destructive acoustic defect detection in drug tablets.

    Science.gov (United States)

    Akseli, Ilgaz; Mani, Girindra N; Cetinkaya, Cetin

    2008-08-06

    For physical defect detection in drug tablets, a non-destructive and non-contact technique based on air coupled excitation and interferometric detection is presented. Physical properties and mechanical integrity of drug tablets can often affect their therapeutic and structural functions. The monitoring for defects and the characterization of tablet mechanical properties therefore have been of practical interest for solid oral dosage forms. The presented monitoring approach is based on the analysis of the transient vibrational responses of an acoustically excited tablet in both in temporal and spectral domains. The pulsed acoustic field exciting the tablet is generated by an air-coupled transducer. Using a laser vibrometer, the out-of-plane vibrational transient response of the tablet is detected and acquired in a non-contact manner. The physical state of the tablet is evaluated based on the spectral properties of these transient responses. In the current study, the effectiveness of three types of simple similarity measures is evaluated for their potential uses as defect detection norms, and for their potential use in quantifying the extent of tablet defect is discussed. It is found that these quantities can not only be used for identification of defective tablets, but could also provide a measure for the extent of the damage.

  13. Acoustics of snoring and automatic snore sound detection in children.

    Science.gov (United States)

    Çavuşoğlu, M; Poets, C F; Urschitz, M S

    2017-10-31

    Acoustic analyses of snoring sounds have been used to objectively assess snoring and applied in various clinical problems for adult patients. Such studies require highly automatized tools to analyze the sound recordings of the whole night's sleep, in order to extract clinically relevant snore- related statistics. The existing techniques and software used for adults are not efficiently applicable to snoring sounds in children, basically because of different acoustic signal properties. In this paper, we present a broad range of acoustic characteristics of snoring sounds in children (N  =  38) in comparison to adult (N  =  30) patients. Acoustic characteristics of the signals were calculated, including frequency domain representations, spectrogram-based characteristics, spectral envelope analysis, formant structures and loudness of the snoring sounds. We observed significant differences in spectral features, formant structures and loudness of the snoring signals of children compared to adults that may arise from the diversity of the upper airway anatomy as the principal determinant of the snore sound generation mechanism. Furthermore, based on the specific audio features of snoring children, we proposed a novel algorithm for the automatic detection of snoring sounds from ambient acoustic data specifically in a pediatric population. The respiratory sounds were recorded using a pair of microphones and a multi-channel data acquisition system simultaneously with full-night polysomnography during sleep. Brief sound chunks of 0.5 s were classified as either belonging to a snoring event or not with a multi-layer perceptron, which was trained in a supervised fashion using stochastic gradient descent on a large hand-labeled dataset using frequency domain features. The method proposed here has been used to extract snore-related statistics that can be calculated from the detected snore episodes for the whole night's sleep, including number of snore episodes

  14. Thermal Acoustic Oscillation: Causes, Detection, Analysis, and Prevention

    Science.gov (United States)

    Christie, R. J.; Hartwig, J. W.

    2014-01-01

    Thermal Acoustic Oscillations (TAO) can occur in cryogenic systems and produce significant sources of heat. This source of heat can increase the boil off rate of cryogenic propellants in spacecraft storage tanks and reduce mission life. This paper discusses the causes of TAO, how it can be detected, what analyses can be done to predict it, and how to prevent it from occurring.The paper provides practical insight into what can aggravate instability, practical methods for mitigation, and when TAO does not occur. A real life example of a cryogenic system with an unexpected heat source is discussed, along with how TAO was confirmed and eliminated.

  15. Steam leak detection in advance reactors via acoustics method

    International Nuclear Information System (INIS)

    Singh, Raj Kumar; Rao, A. Rama

    2011-01-01

    Highlights: → Steam leak detection system is developed to detect any leak inside the reactor vault. → The technique uses leak noise frequency spectrum for leak detection. → Testing of system and method to locate the leak is also developed and discussed in present paper. - Abstract: Prediction of LOCA (loss of coolant activity) plays very important role in safety of nuclear reactor. Coolant is responsible for heat transfer from fuel bundles. Loss of coolant is an accidental situation which requires immediate shut down of reactor. Fall in system pressure during LOCA is the trip parameter used for initiating automatic reactor shut down. However, in primary heat transport system operating in two phase regimes, detection of small break LOCA is not simple. Due to very slow leak rates, time for the fall of pressure is significantly slow. From reactor safety point of view, it is extremely important to find reliable and effective alternative for detecting slow pressure drop in case of small break LOCA. One such technique is the acoustic signal caused by LOCA in small breaks. In boiling water reactors whose primary heat transport is to be driven by natural circulation, small break LOCA detection is important. For prompt action on post small break LOCA, steam leak detection system is developed to detect any leak inside the reactor vault. The detection technique is reliable and plays a very important role in ensuring safety of the reactor. Methodology developed for steam leak detection is discussed in present paper. The methods to locate the leak is also developed and discussed in present paper which is based on analysis of the signal.

  16. Nonlinear vibro-acoustic technique for land mine detection

    Science.gov (United States)

    Donskoy, Dmitri M.

    1998-09-01

    The innovative technique for detection of artificial objects, such as mines, pipes, containers, etc., buried in the ground, is developed and tested. The technique does not depend upon the material from which the object is fabricated whether it be metal, plastic, wood, or any other material. It depends upon the fact that a mine is a 'shell' whose purpose is to contain explosive materials and associated detonation apparatus. The mine shell is in contact with the soil in which it is buried. The shell is an acoustically compliant article, which compliance is notably different from the compliance of the surrounding soil. This difference is responsible for the mechanically nonlinear behavior of the soil/shell interface making it the detectable entity. Thus for this new technology, the fact that the mine is buried is turned to a detection advantage. Because the technique intrinsically detects buried 'shells,' it is insensitive to rocks, tree roots, chunks of metal, bricks, etc. which was confirmed experimentally. The paper discusses physical mechanisms of the nonlinear behavior of the soil-mine interface, the results of experimental investigation of the observed nonlinear interaction, and demonstration of landmine detection technique based on the discovered phenomenon.

  17. DETECTION OF DRUGSTORE BEETLES IN 9975 PACKAGES USING ACOUSTIC EMISSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Shull, D.

    2013-03-04

    This report documents the initial feasibility tests performed using a commercial acoustic emission instrument for the purpose of detecting beetles in Department of Energy 9975 shipping packages. The device selected for this testing was a commercial handheld instrument and probe developed for the detection of termites, weevils, beetles and other insect infestations in wooden structures, trees, plants and soil. The results of two rounds of testing are presented. The first tests were performed by the vendor using only the hand-held instrument’s indications and real-time operator analysis of the audio signal content. The second tests included hands-free positioning of the instrument probe and post-collection analysis of the recorded audio signal content including audio background comparisons. The test results indicate that the system is promising for detecting the presence of drugstore beetles, however, additional work would be needed to improve the ease of detection and to automate the signal processing to eliminate the need for human interpretation. Mechanisms for hands-free positioning of the probe and audio background discrimination are also necessary for reliable detection and to reduce potential operator dose in radiation environments.

  18. Detection of appearing and disappearing objects in complex acoustic scenes.

    Directory of Open Access Journals (Sweden)

    Francisco Cervantes Constantino

    Full Text Available The ability to detect sudden changes in the environment is critical for survival. Hearing is hypothesized to play a major role in this process by serving as an "early warning device," rapidly directing attention to new events. Here, we investigate listeners' sensitivity to changes in complex acoustic scenes-what makes certain events "pop-out" and grab attention while others remain unnoticed? We use artificial "scenes" populated by multiple pure-tone components, each with a unique frequency and amplitude modulation rate. Importantly, these scenes lack semantic attributes, which may have confounded previous studies, thus allowing us to probe low-level processes involved in auditory change perception. Our results reveal a striking difference between "appear" and "disappear" events. Listeners are remarkably tuned to object appearance: change detection and identification performance are at ceiling; response times are short, with little effect of scene-size, suggesting a pop-out process. In contrast, listeners have difficulty detecting disappearing objects, even in small scenes: performance rapidly deteriorates with growing scene-size; response times are slow, and even when change is detected, the changed component is rarely successfully identified. We also measured change detection performance when a noise or silent gap was inserted at the time of change or when the scene was interrupted by a distractor that occurred at the time of change but did not mask any scene elements. Gaps adversely affected the processing of item appearance but not disappearance. However, distractors reduced both appearance and disappearance detection. Together, our results suggest a role for neural adaptation and sensitivity to transients in the process of auditory change detection, similar to what has been demonstrated for visual change detection. Importantly, listeners consistently performed better for item addition (relative to deletion across all scene interruptions used

  19. Damage Detection in Railway Prestressed Concrete Sleepers using Acoustic Emission

    Science.gov (United States)

    Clark, A.; Kaewunruen, S.; Janeliukstis, R.; Papaelias, M.

    2017-10-01

    Prestressed concrete sleepers (or railroad ties) are safety-critical elements in railway tracks that distribute the wheel loads from the rails to the track support system. Over a period of time, the concrete sleepers age and deteriorate in addition to experiencing various types of static and dynamic loading conditions, which are attributable to train operations. In many cases, structural cracks can develop within the sleepers due to high intensity impact loads or due to poor track maintenance. Often, cracks of sleepers develop and present at the midspan due to excessive negative bending. These cracks can cause broken sleepers and sometimes called ‘center bound’ problem in railway lines. This paper is the world first to present an application of non-destructive acoustic emission technology for damage detection in railway concrete sleepers. It presents experimental investigations in order to detect center-bound cracks in railway prestressed concrete sleepers. Experimental laboratory testing involves three-point bending tests of four concrete sleepers. Three-point bending tests correspond to a real failure mode, when the loads are not transferred uniformly to the ballast support. It is observed that AE sensing provides an accurate means for detecting the location and magnitude of cracks in sleepers. Sensor location criticality is also highlighted in the paper to demonstrate the reliability-based damage detection of the sleepers.

  20. A New Acoustic Emission Sensor Based Gear Fault Detection Approach

    Directory of Open Access Journals (Sweden)

    Junda Zhu

    2013-01-01

    Full Text Available In order to reduce wind energy costs, prognostics and health management (PHM of wind turbine is needed to ensure the reliability and availability of wind turbines. A gearbox is an important component of a wind turbine. Therefore, developing effective gearbox fault detection tools is important to the PHM of wind turbine. In this paper, a new acoustic emission (AE sensor based gear fault detection approach is presented. This approach combines a heterodyne based frequency reduction technique with time synchronous average (TSA and spectrum kurtosis (SK to process AE sensor signals and extract features as condition indictors for gear fault detection. Heterodyne technique commonly used in communication is first employed to preprocess the AE signals before sampling. By heterodyning, the AE signal frequency is down shifted from several hundred kHz to below 50 kHz. This reduced AE signal sampling rate is comparable to that of vibration signals. The presented approach is validated using seeded gear tooth crack fault tests on a notational split torque gearbox. The approach presented in this paper is physics based and the validation results have showed that it could effectively detect the gear faults.

  1. Determination of acoustic speed for improving leak detection and location in gas pipelines.

    Science.gov (United States)

    Li, Shuaiyong; Wen, Yumei; Li, Ping; Yang, Jin; Yang, Lili

    2014-02-01

    The commonly used cross-correlation technique for leak location requires that the acoustic speed is known and invariable. In practice, the gas leakage-induced acoustic waves propagate along multiple paths including in-pipe gas and pipe wall, and the acoustic waves in different transmission paths exhibit different acoustic speeds and different dispersive behaviors, which bring a great challenge for leak detection and location in the gas pipelines. In this study, based on the vibration theory of cylindrical elastic thin shell, the wavenumber formulae in different transmission paths are derived to predict the acoustic speeds and the acoustical coupling between the in-pipe gas and the pipe wall is analyzed to determine the dominant transmission path. In addition, the velocity dispersions in the dominant transmission path are suppressed by selection of a characteristic frequency band of the gas leakage-induced acoustic waves. The theoretical predictions are verified in the experiment and the results show that the theoretical acoustic speed is slightly larger than the measured acoustic speed. Thus, the theoretical acoustic speed formula is modified considering the effect of the structural loss factor and consequently the location error using the modified acoustic speed is reduced by two times compared to that using the theoretical acoustic speed.

  2. Acoustic system for pipe rupture monitoring and leak detection

    International Nuclear Information System (INIS)

    Herzog, W.; Jonas, H.

    1982-06-01

    As a safety aspect pipe rupture and leakage effects are of particular interest in nuclear power plants where severe consequences for the reactor may result. Counter measures against postulated pipe breaks and leakages in nuclear power plants are necessary whenever the main safety goals: safe shut-down, safe afterheat removal and retention of radioactivity, are endangered. The requirements to be met by a leak detection system depend on the time available for counter actions. If this time is short so that automatic actions are necessary the German safety criteria for nuclear power plants (Criterion 6.1) require two physically diverse signals to be monitored. One fairly obvious possibility of leak detection is to monitor process parameters (pressure, flow). As a diverse signal physical parameters outside the process may be employed: pressure transients temperature, humidity are principally suitable. In practical application, however, it is difficult to predict these parameters by way of calculation in order to establish the required set-point of the monitoring system. Experimental determination is possible only in special cases. A study of several ways of diverse leak detection methods leads to the very promising acoustic method. We investigated experimentally the feasibility of monitoring the sound created by a leakage. Air borne sound as well as body borne sound was analyzed

  3. Multiuser sonar watermarking and detection in an underwater acoustic channel

    Science.gov (United States)

    Mobasseri, Bijan G.; Lynch, Robert S.; Andiario, David

    2013-06-01

    Sonar watermarking is the practice of embedding low-power, secure digital signatures in the time frequency space of a waveform. The algorithm is designed for a single source/receiver configuration. However, in a multiuser environment, multiple sources broadcast sonar waveforms that overlap in both time and frequency. The receiver can be configured as a filter bank where each bank is dedicated to detecting a specific watermark. However, a filter bank is prone to mutual interference as multiple sonar waveforms are simultaneously present at the detector input. To mitigate mutual interference, a multiuser watermark detector is formulated as a decorrelating detector that decouples detection amongst the watermark signatures. The acoustic channel is simulated in software and modeled by an FIR filter. This model is used to compensate for the degradation of spreading sequences used for watermark embedding. The test statistic generated at the output of the decorrelating detector is used in a joint maximum likelihood ratio detector to establish the presence or absence of the watermark in each sonar waveform. ROC curves are produced for multiple sources positioned at varying ranges subject to ambient ocean noise controlled by varying sea states.

  4. New methods for leaks detection and localisation using acoustic emission

    International Nuclear Information System (INIS)

    Boulanger, P.

    1993-01-01

    Real time monitoring of Pressurized Water nuclear Reactor secondary coolant system tends to integrate digital processing machines. In this context, the method of acoustic emission seems to exhibit good performances. Its principle is based on passive listening of noises emitted by local micro-displacements inside a material under stress which propagate as elastic waves. The lack of a priori knowledge on leak signals leads us to go deeper into understanding flow induced noise generation. Our studies are conducted using a simple leak model depending on the geometry and the king of flow inside the slit. Detection and localization problems are formulated according to the maximum likelihood principle. For detection, the methods using a indicator of similarity (correlation, higher order correlation) seems to give better results than classical ones (rms value, envelope, filter banks). For leaks location, a large panel of classical (generalized inter-correlation) and innovative (convolution, adaptative, higher order statistics) methods of time delay estimation are presented. The last part deals with the applications of higher order statistics. The analysis of higher order estimators of a non linear non Gaussian stochastic process family, the improvement of non linear prediction performances and the optimal-order choice problem are addressed in simple analytic cases. At last, possible applications to leak signals analysis are pointed out. (authors).264 refs., 7 annexes

  5. Damage detection in wind turbine blades using acoustic techniques

    International Nuclear Information System (INIS)

    Juengert, A.

    2013-01-01

    Facing climate change, the use of renewable energy gains importance. The wind energy sector grows very fast. Bigger and more powerful wind turbines will be built in the coming decades and the safety and reliability of the turbines will become more important. Wind turbine blades have to be inspected at regular intervals, because they are highly stressed during operation and a blade breakdown can cause big economic damages. The turbine blades consist of fiber reinforced plastics (GFRP/CFRP) and sandwich areas containing wood or plastic foam. The blades are manufactured as two halves and glued together afterwards. Typical damages are delaminations within the GFRP or the sandwich and missing adhesive or deficient bond at the bonding surfaces. The regular inspections of wind turbine blades are performed manually by experts and are limited to visual appraisals and simple tapping tests. To improve the inspections of wind turbine blades non-destructive testing techniques using acoustic waves are being developed. To detect delaminations within the laminates of the turbine blade, a local resonance spectroscopy was used. To detect missing bond areas from the outside of the blade the impulse-echo-technique was applied. This paper is an updated reprint of an article published on ndt.net in 2008. (author)

  6. Non-destructive Leak Detection in Galvanized Iron Pipe Using Nonlinear Acoustic Modulation Method

    OpenAIRE

    Priyandoko, Gigih

    2018-01-01

    Non-destructive testing is a wide group of analysis techniques used in science and industry to evaluate the properties of a structure without causing damage to it. The main objective of this project is to carry out experiment to detect leakage in pipeline using nonlinear acoustic modulation method. The nonlinear acoustic modulation approach with low frequency excitation and high frequency acoustic wave is used to reveal modulations in the presence of leak. The pipe used in this experiment was...

  7. Active acoustic leak detection for LMFBR steam generators. Pt. 7. Potential for small leak detection

    International Nuclear Information System (INIS)

    Kumagai, Hiromichi; Yoshida, Kazuo

    1998-01-01

    In order to prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of fast breeder reactors (FBR), it is necessary to detect precisely and immediately the leakage of water from heat transfer tubes. Therefore, an active acoustic method, which detects the sound attenuation due to bubbles generated in the sodium-water reactions, is being developed. Previous studies have revealed that the active acoustic method can detect bubbles of 10 l/s (equivalence water leak rate about 10 g/s) within 10 seconds in practical steam generators. In order to prevent the expansion of damage to neighboring tubes, however, it is necessary to detect smaller leakage of water from heat transfer tubes. In this study, in order to evaluate the detection sensitivity of the active method, the signal processing methods for emitter and receiver sound and the detection method for leakage within 1 g/s are investigated experimentally, using an SG full-sector model that simulates the actual SGs. A typical result shows that detection of 0.4 l/s air bubbles (equivalent water leak rate about 0.4 g/s) takes about 80 seconds, which is shorter than the propagation time of damage to neighboring tubes. (author)

  8. Acoustic detection for water/steam leak from a tube of LMFBR steam generator

    International Nuclear Information System (INIS)

    Sonoda, Masataka; Shindo, Yoshihisa

    1989-01-01

    Acoustic leak detector is useful for detecting more quickly intermediate leak than the existing hydrogen detector and is available for identification of leak location on the accident of water/steam leak from a tube of LMFBR steam generator. This paper presents the overview of HALD (High frequency Acoustics Leak Detection) system, which is more sensitive for leak detection and lower cost of equipment for identification of leak location than a low frequency type detector. (author)

  9. CO2 leak detection through acoustic sensing and infrared imaging

    Science.gov (United States)

    Cui, Xiwang; Yan, Yong; Ma, Lin; Ma, Yifan; Han, Xiaojuan

    2014-04-01

    When CO2 leakage occurs from a high pressure enclosure, the CO2 jet formed can produce fierce turbulent flow generating acoustic emission with possible phase change, depending on the pressure of the enclosure, and a significant temperature drop in the region close to the releasing point. Acoustic Emission (AE) and infrared imaging technologiesare promising methods for on-line monitoring of such accidental leakage. In this paper, leakage experiments were carried out with a CO2 container under well controlled conditions in a laboratory. Acoustic signals and temperature distribution at the leakage area were acquired using an acoustic sensor and an infraredthermalimaging camera. The acoustic signal was analyzed in both time and frequency domains. The characteristics of the signal frequencies areidentified, and their suitability for leakage detectionis investigated. The location of the leakage can be identified by seeking the lowest temperature area or point in the infrared image.

  10. Acoustic detection of high energy neutrinos in sea water: status and prospects

    Directory of Open Access Journals (Sweden)

    Lahmann Robert

    2017-01-01

    Full Text Available The acoustic neutrino detection technique is a promising approach for future large-scale detectors with the aim of measuring the small expected flux of neutrinos at energies in the EeV-range and above. The technique is based on the thermo-acoustic model, which implies that the energy deposition by a particle cascade – resulting from a neutrino interaction in a medium with suitable thermal and acoustic properties – leads to a local heating and a subsequent characteristic pressure pulse that propagates in the surrounding medium. Current or recent test setups for acoustic neutrino detection have either been add-ons to optical neutrino telescopes or have been using acoustic arrays built for other purposes, typically for military use. While these arrays have been too small to derive competitive limits on neutrino fluxes, they allowed for detailed studies of the experimental technique. With the advent of the research infrastructure KM3NeT in the Mediterranean Sea, new possibilities will arise for acoustic neutrino detection. In this article, results from the “first generation” of acoustic arrays will be summarized and implications for the future of acoustic neutrino detection will be discussed.

  11. Acoustic impact testing and waveform analysis for damage detection in glued laminated timber

    Science.gov (United States)

    Feng Xu; Xiping Wang; Marko Teder; Yunfei Liu

    2017-01-01

    Delamination and decay are common structural defects in old glued laminated timber (glulam) buildings, which, if left undetected, could cause severe structural damage. This paper presents a new damage detection method for glulam inspection based on moment analysis and wavelet transform (WT) of impact acoustic signals. Acoustic signals were collected from a glulam arch...

  12. Development of an acoustic steam generator leak detection system using delay-and-sum beamformer

    International Nuclear Information System (INIS)

    Chikazawa, Yoshitaka

    2009-01-01

    A new acoustic steam generator leak detection system using delay-and-sum beamformer is proposed. The major advantage of the delay-and-sum beamformer is it could provide information of acoustic source direction. An acoustic source of a sodium-water reaction is supposed to be localized while the background noise of the steam generator operation is uniformly distributed in the steam generator tube region. Therefore the delay-and-sum beamformer could distinguish the acoustic source of the sodium-water reaction from steam generator background noise. In this paper, results from numerical analyses are provided to show fundamental feasibility of the new method. (author)

  13. Acoustic damage detection in laser-cut CFRP composite materials

    Science.gov (United States)

    Nishino, Michiteru; Harada, Yoshihisa; Suzuki, Takayuki; Niino, Hiroyuki

    2012-03-01

    Carbon fiber reinforced plastics (CFRP) composite material, which is expected to reduce the weight of automotive, airplane and etc., was cut by laser irradiation with a pulsed-CO2 laser (TRUMPF TFL5000; P=800W, 20kHz, τ=8μs, λ=10.6μm, V=1m/min) and single-mode fiber lasers (IPG YLR-300-SM; P=300W, λ=1.07μm, V=1m/min)(IPG YLR- 2000-SM; P=2kW, λ=1.07μm, V=7m/min). To detect thermal damage at the laser cutting of CFRP materials consisting of thermoset resin matrix and PAN or PITCH-based carbon fiber, the cut quality was observed by X-ray CT. The effect of laser cutting process on the mechanical strength for CFRP tested at the tensile test. Acoustic emission (AE) monitoring, high-speed camera and scanning electron microscopy were used for the failure process analysis. AE signals and fractographic features characteristic of each laser-cut CFRP were identified.

  14. Acoustic detection, tracking, and characterization of three tornadoes.

    Science.gov (United States)

    Frazier, William Garth; Talmadge, Carrick; Park, Joseph; Waxler, Roger; Assink, Jelle

    2014-04-01

    Acoustic data recorded at 1000 samples per second by two sensor arrays located at ranges of 1-113 km from three tornadoes that occurred on 24 May 2011 in Oklahoma are analyzed. Accurate bearings to the tornadoes have been obtained using beamforming methods applied to the data at infrasonic frequencies. Beamforming was not viable at audio frequencies, but the data demonstrate the ability to detect significant changes in the shape of the estimated power spectral density in the band encompassing 10 Hz to approximately 100 Hz at distances of practical value from the sensors. This suggests that arrays of more closely spaced sensors might provide better bearing accuracy at practically useful distances from a tornado. Additionally, a mathematical model, based on established relationships of aeroacoustic turbulence, is demonstrated to provide good agreement to the estimated power spectra produced by the tornadoes at different times and distances from the sensors. The results of this analysis indicate that, qualitatively, an inverse relationship appears to exist between the frequency of an observed peak of the power spectral density and the reported tornado intensity.

  15. Performance Test for Developing the Acoustic Leak Detection System of the LMR Steam Generator

    International Nuclear Information System (INIS)

    Kim, Tae Joon; Jeong, Ji Young; Hur, Seop

    2005-01-01

    The successful detection of a water/steam into a sodium leak in the LMR SG (steam generator) at an early phase of a leak origin depends on the fast response and sensitivity of a leak detection system. It is considered, that the acoustic system is intended for a fast detecting of a water/steam into a sodium leak of an intermediate flow rate, 1 ∼ 10 g/s, during several seconds. This intention of an acoustic leak detection system is stipulated by a key impossibility of a fast detecting of an intermediate leak by the present nominal systems such as the hydrogen meter. Subject of this study is to introduce the detection performance of the acoustic leak detection system discriminated by a back-propagation neural network with a preprocessing of the FFT power spectrum analysis and the Octave band analysis, and to introduce the status of the development of the acoustic leak detection in KAERI. It was used with the acoustic signals from the injected Argon gas into water experiments in KAERI, the acoustic signals injected from the water into the sodium obtained in IPPE, and the background noise of the PFR superheater

  16. Acoustics

    Science.gov (United States)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  17. Application of acoustic leak detection technology for the detection and location of leaks in light water reactors

    International Nuclear Information System (INIS)

    Kupperman, D.S.; Prine, D.; Mathieson, T.

    1988-10-01

    This report presents the results of a study to evaluate the adequacy of leak detection systems in light water reactors. The sources of numerous reported leaks and methods of detection have been documented. Research to advance the state of the art of acoustic leak detection is presented, and procedures for implementation are discussed. 14 refs., 70 figs., 10 tabs

  18. A Four-Quadrant PVDF Transducer for Surface Acoustic Wave Detection

    Directory of Open Access Journals (Sweden)

    Zhi Chen

    2012-08-01

    Full Text Available In this paper, a polyvinylidene fluoride (PVDF piezoelectric transducer was developed to detect laser-induced surface acoustic waves in a SiO2-thin film–Si-substrate structure. In order to solve the problems related to, firstly, the position of the probe, and secondly, the fact that signals at different points cannot be detected simultaneously during the detection process, a four-quadrant surface acoustic wave PVDF transducer was designed and constructed for the purpose of detecting surface acoustic waves excited by a pulse laser line source. The experimental results of the four-quadrant piezoelectric detection in comparison with the commercial nanoindentation technology were consistent, the relative error is 0.56%, and the system eliminates the piezoelectric surface wave detection direction deviation errors, improves the accuracy of the testing system by 1.30%, achieving the acquisition at the same time at different testing positions of the sample.

  19. Theory, simulation and experimental results of the acoustic detection of magnetization changes in superparamagnetic iron oxide

    Directory of Open Access Journals (Sweden)

    Borgert Jörn

    2011-06-01

    Full Text Available Abstract Background Magnetic Particle Imaging is a novel method for medical imaging. It can be used to measure the local concentration of a tracer material based on iron oxide nanoparticles. While the resulting images show the distribution of the tracer material in phantoms or anatomic structures of subjects under examination, no information about the tissue is being acquired. To expand Magnetic Particle Imaging into the detection of soft tissue properties, a new method is proposed, which detects acoustic emissions caused by magnetization changes in superparamagnetic iron oxide. Methods Starting from an introduction to the theory of acoustically detected Magnetic Particle Imaging, a comparison to magnetically detected Magnetic Particle Imaging is presented. Furthermore, an experimental setup for the detection of acoustic emissions is described, which consists of the necessary field generating components, i.e. coils and permanent magnets, as well as a calibrated microphone to perform the detection. Results The estimated detection limit of acoustic Magnetic Particle Imaging is comparable to the detection limit of magnetic resonance imaging for iron oxide nanoparticles, whereas both are inferior to the theoretical detection limit for magnetically detected Magnetic Particle Imaging. Sufficient data was acquired to perform a comparison to the simulated data. The experimental results are in agreement with the simulations. The remaining differences can be well explained. Conclusions It was possible to demonstrate the detection of acoustic emissions of magnetic tracer materials in Magnetic Particle Imaging. The processing of acoustic emission in addition to the tracer distribution acquired by magnetic detection might allow for the extraction of mechanical tissue parameters. Such parameters, like for example the velocity of sound and the attenuation caused by the tissue, might also be used to support and improve ultrasound imaging. However, the method

  20. Acoustic target detection and classification using neural networks

    Science.gov (United States)

    Robertson, James A.; Conlon, Mark

    1993-01-01

    A neural network approach to the classification of acoustic emissions of ground vehicles and helicopters is demonstrated. Data collected during the Joint Acoustic Propagation Experiment conducted in July of l991 at White Sands Missile Range, New Mexico was used to train a classifier to distinguish between the spectrums of a UH-1, M60, M1 and M114. An output node was also included that would recognize background (i.e. no target) data. Analysis revealed specific hidden nodes responding to the features input into the classifier. Initial results using the neural network were encouraging with high correct identification rates accompanied by high levels of confidence.

  1. Development of the On-line Acoustic Leak Detection Tool for the SFR Steam Generator Protection

    International Nuclear Information System (INIS)

    Kim, Tae-Joon; Jeong, Ji-Young; Kim, Jong-Man; Kim, Byung-Ho; Kim, Seong-O

    2007-01-01

    The successful detection of a water/steam into a sodium leak in the SFR SG (steam generator) at an early phase of a leak origin depends on the fast response and sensitivity of a leak detection system. This intention of an acoustic leak detection system is stipulated by a key impossibility of a fast detecting of an intermediate leak by the present nominal systems such as the hydrogen meter. Subject of this study is to introduce the detection performance of an on-line acoustic leak detection tool discriminated by a back-propagation neural network with a preprocessing of the 1/m Octave band analysis, and to introduce the status of an on-line development being developed with the acoustic leak detection tool(S/W) in KAERI. For a performance test, it was used with the acoustic signals for a sodium-water reaction from the injected steam into water experiments in KAERI, the acoustic signals injected from the water into the sodium obtained in IPPE, and the background noise of the PFR superheater

  2. Effect of a Background Noise on the Acoustic Leak Detection Methodology for a SFR Steam Generator

    International Nuclear Information System (INIS)

    Kim, Tae-Joon; Jeong, Ji-Young; Kim, Jong-Man

    2007-01-01

    The protection of a water/steam leak into a sodium in the SFR SG at an early phase of a leak origin depends on a fast response and sensitivity of a leak detection system not to a response against the several kinds of noises. The subject in this study is to introduce a detection performance by using our developed acoustic leak detection methodology discriminated by a backpropagation neural network according to a preprocessing of the 1/6 Octave band analysis or 1/12 Octave band analysis and the x n method defined by us. It was used for the acoustic signals generated from the simulation works which are the noises of an artificial background such as a scratching, a hammering on a steel structure and so on. In a previous study, we showed that the performance of a LabVIEW tool embedded with the developed acoustic leak detection methodology detected the SWR leak signals

  3. Detection of Suspicious Mass on Structures by Acoustical Waves

    Czech Academy of Sciences Publication Activity Database

    Trnka, Jan; Stoklasová, Pavla; Norris, C.S.P.

    2012-01-01

    Roč. 36, č. 3 (2012), s. 14-21 ISSN 0732-8818 R&D Projects: GA ČR GA101/07/0588 Institutional support: RVO:61388998 Keywords : pulse holointerferometry * pulse electronic speckle patterns interferometry * laser vibrometry * lamb waves Subject RIV: BI - Acoustics Impact factor: 0.378, year: 2012

  4. Results of investigations within the IWGFR benchmark test acoustic boiling noise detection

    International Nuclear Information System (INIS)

    Mauersberger, H.; Froehlich, K.J.

    1989-01-01

    The present paper deals with investigations of acoustic signals from a boiling experiment performed on the KNS I loop at KfK Karlsruhe. Signals have been analysed in frequency as well as in time domain. Signal characteristics successfully used to detect the boiling process have been found in time domain. A proposal for in-service boiling monitoring by acoustic means is briefly described. (author). 10 refs, 16 figs, 1 tab

  5. Acoustic detection of UHE neutrinos in the Mediterranean sea: status and perspective

    Directory of Open Access Journals (Sweden)

    Simeone Francesco

    2017-01-01

    Full Text Available In recent years the astro-particle community is involved in the realization of experimental apparatuses for the detection of high energy neutrinos originated in cosmic sources or produced in the interaction of Cosmic Rays with the Cosmic Microwave Background. For neutrino energies in the TeV-PeV range, optical Cherenkov detectors, that have been so far positively exploited by Baikal[1], IceCube[2] and ANTARES[3], are considered optimal. For higher energies, three different experimental techniques are under study: the detection of radio pulses produced by showers induced by a neutrino interaction, the detection of air showers initiated by neutrinos interacting with rocks or deep Earth’s atmosphere and the detection of acoustic waves produced by deposition of energy following the interaction of neutrinos in an acoustically transparent medium. The potential of the acoustic detection technique, first proposed by Askaryan[4], to build very large neutrino detectors is appealing, thanks to the optimal properties of media such as water or ice as sound propagator. Though the studies on this technique are still in an early stage, acoustic positioning systems used to locate the optical modules in underwater Cherenkov neutrino detectors, give the possibility to study the ambient noise and provide important information for the future analysis of acoustic data.

  6. YIP Expansion: Ocean Basin Impact of Ambient Noise on Marine Mammal Detectability, Distribution, and Acoustic Communication

    Science.gov (United States)

    2015-09-30

    Marine Mammal Detectability, Distribution, and Acoustic Communication Jennifer L. Miksis-Olds Applied Research Laboratory The Pennsylvania State...from Selected CTBTO 5 Hydroacoustic Sites”. Patterns and trends of ocean sound observed in this study will also be directly applicable to the...Detection and Estimation Theory. Research Laboratory of Electronics (RLE) at the Massachusetts Institute of Technology (MIT). PUBLICATIONS None

  7. Acoustic sodium-water reaction detection of the Phenix steam generators

    International Nuclear Information System (INIS)

    Carminati, M.; Martin, L.; Sauzaret, A.

    1990-01-01

    The systems for acoustic sodium-water reaction detection and hydrogen detection of the Phenix steam generators as well as systems for monitoring signals analysis and processing are described. It is reported that the results obtained during operation and calibration phases are very encouraging and that industrial equipment showing the same performance are being examined. 6 figs

  8. Bat detective-Deep learning tools for bat acoustic signal detection.

    Science.gov (United States)

    Mac Aodha, Oisin; Gibb, Rory; Barlow, Kate E; Browning, Ella; Firman, Michael; Freeman, Robin; Harder, Briana; Kinsey, Libby; Mead, Gary R; Newson, Stuart E; Pandourski, Ivan; Parsons, Stuart; Russ, Jon; Szodoray-Paradi, Abigel; Szodoray-Paradi, Farkas; Tilova, Elena; Girolami, Mark; Brostow, Gabriel; Jones, Kate E

    2018-03-01

    Passive acoustic sensing has emerged as a powerful tool for quantifying anthropogenic impacts on biodiversity, especially for echolocating bat species. To better assess bat population trends there is a critical need for accurate, reliable, and open source tools that allow the detection and classification of bat calls in large collections of audio recordings. The majority of existing tools are commercial or have focused on the species classification task, neglecting the important problem of first localizing echolocation calls in audio which is particularly problematic in noisy recordings. We developed a convolutional neural network based open-source pipeline for detecting ultrasonic, full-spectrum, search-phase calls produced by echolocating bats. Our deep learning algorithms were trained on full-spectrum ultrasonic audio collected along road-transects across Europe and labelled by citizen scientists from www.batdetective.org. When compared to other existing algorithms and commercial systems, we show significantly higher detection performance of search-phase echolocation calls with our test sets. As an example application, we ran our detection pipeline on bat monitoring data collected over five years from Jersey (UK), and compared results to a widely-used commercial system. Our detection pipeline can be used for the automatic detection and monitoring of bat populations, and further facilitates their use as indicator species on a large scale. Our proposed pipeline makes only a small number of bat specific design decisions, and with appropriate training data it could be applied to detecting other species in audio. A crucial novelty of our work is showing that with careful, non-trivial, design and implementation considerations, state-of-the-art deep learning methods can be used for accurate and efficient monitoring in audio.

  9. Development of an incipient rotor crack detection method by acoustic emission techniques

    International Nuclear Information System (INIS)

    Le Reverend, D.; Massouri, M.H.

    1988-01-01

    The objective of the program presented is to develop a method of detection and monitoring of crack growth in machine rotor by application of acoustic emission techniques. This program is performed by R and D Division of Electricite de France, jointly with INSA de Lyon. The first task of the program is relative to the characterization of acoustic emission during a progressive tensile test performed on a NCT specimen. The second task of the program deals with the experimentation of acoustic emission techniques for the monitoring of a specimen during cycling bending tests. The last task of the program is relative to evaluation of application of acoustic emission techniques for a small rotor integrity monitoring during fatigue rotation tests [fr

  10. AMADEUS—The acoustic neutrino detection test system of the ANTARES deep-sea neutrino telescope

    Science.gov (United States)

    Aguilar, J. A.; Al Samarai, I.; Albert, A.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-Cabo, M.; Bouwhuis, M. C.; Brown, A.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Cârloganu, C.; Carminati, G.; Carr, J.; Cassano, B.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, Ph.; Chiarusi, T.; Chon Sen, N.; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; de Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J.-P.; Escoffier, S.; Fehr, F.; Fiorello, C.; Flaminio, V.; Fritsch, U.; Fuda, J.-L.; Gay, P.; Giacomelli, G.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Heijboer, A. J.; Heine, E.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; de Jong, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Keller, P.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Lahmann, R.; Lamare, P.; Lambard, G.; Larosa, G.; Laschinsky, H.; Le Provost, H.; Lefèvre, D.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Mazure, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Ostasch, R.; Palioselitis, D.; Păvălaş, G. E.; Payre, P.; Petrovic, J.; Picot-Clemente, N.; Picq, C.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Radu, A.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Sapienza, P.; Schöck, F.; Schuller, J.-P.; Shanidze, R.; Simeone, F.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.

    2011-01-01

    The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic sensors, installed at water depths between 2050 and 2300 m, employ piezo-electric elements for the broad-band recording of signals with frequencies ranging up to 125 kHz. The typical sensitivity of the sensors is around -145 dB re 1 V/μPa (including preamplifier). Completed in May 2008, AMADEUS consists of six “acoustic clusters”, each comprising six acoustic sensors that are arranged at distances of roughly 1 m from each other. Two vertical mechanical structures (so-called lines) of the ANTARES detector host three acoustic clusters each. Spacings between the clusters range from 14.5 to 340 m. Each cluster contains custom-designed electronics boards to amplify and digitise the acoustic signals from the sensors. An on-shore computer cluster is used to process and filter the data stream and store the selected events. The daily volume of recorded data is about 10 GB. The system is operating continuously and automatically, requiring only little human intervention. AMADEUS allows for extensive studies of both transient signals and ambient noise in the deep sea, as well as signal correlations on several length scales and localisation of acoustic point sources. Thus the system is excellently suited to assess the background conditions for the measurement of the bipolar pulses expected to originate from neutrino interactions.

  11. Sodium boiling detection in LMFBRs by acoustic-neutronic cross correlation

    International Nuclear Information System (INIS)

    Wright, S.A.

    1977-01-01

    The acoustic and neutronic noise signals caused by boiling are the signals primarily considered likely to detect sodium boiling in an LMFBR. Unfortunately, these signals may have serious signal-to-noise problems due to strong background noise sources. Neutronic-acoustic cross correlation techniques are expected to provide a means of improving the signal-to-noise ratio. This technique can improve the signal-to-noise ratio because the neutronic and acoustic signals due to boiling are highly correlated near the bubble repetition frequency, while the background noise sources are expected to be uncorrelated (or at most weakly correlated). An experiment was designed to show that the neutronic and acoustic noise signals are indeed highly correlated. The experiment consisted of simulating the void and pressure effects of local sodium boiling in the core of a zero-power reactor (ARK). The analysis showed that the neutronic and acoustic noise signals caused by boiling are almost perfectly correlated in a wide frequency band about the bubble repetition frequency. The results of the experiments were generalized to full-scale reactors to compare the inherent effectiveness of the methods which use the neutronic or acoustic signals alone with a hybrid method, which cross correlates the neutronic and acoustic signals. It was concluded that over a zone of the reactor where the void coefficient is sufficiently large (approximately 85 percent the core volume), the cross correlation method can provide a more rapid detection system for a given signal-to-noise ratio. However, where the void coefficient is small, one must probably rely on the acoustic method alone

  12. The current status of research and development concerning steam generator acoustic leak detection for the demonstration FBR plant

    International Nuclear Information System (INIS)

    Higuchi, Masahisa

    1990-01-01

    The Japan Atomic Power Co. (JAPC) started the research and development into Acoustic Leak Detection for the Demonstration FBR (D-FBR) plant in 1989. Acoustic Leak Detection is expected as a water leak detection system in the Steam Generator for the first D-FBR plant. JAPC is presently analyzing data on Acoustic Leak Detection in order to form some basic concepts and basic specifications about leak detection. Both low frequency types and high frequency types are selected as candidates for Acoustic Leak Detection. After a review of both types, either one will be selected for the D-FBT plant. A detailed Research and Development plan on Acoustic Leak Detection, which should be carried out prior to starting the construction of the D-FBR plant, is under review. (author). 3 figs, 2 tabs

  13. Status of U.S. evaluations of acoustic detection of in-sodium water leaks

    International Nuclear Information System (INIS)

    Fletcher, F.L.; Neely, H.H.

    1990-01-01

    An overview of the United States testing program to evaluate acoustic leak detection and location systems on simulated water leaks in functional liquid sodium steam generators is provided. Testing was conducted on the modular hockey stick steam generator during the large leak test program in the LLTR, on the CRBR prototype hockey stick steam generators in SCTI, on a double wall tube steam generator installed in EBR-II and on the helical coil steam generator tested in SCTI. These test programs have demonstrated the acoustic leak detection system potential, however, additional development is required before the system can perform to its effective and required potential. (author). 6 figs

  14. Acoustic detection of melanosome transport in Xenopus laevis melanophores.

    Science.gov (United States)

    Frost, Rickard; Norström, Elisabeth; Bodin, Lovisa; Langhammer, Christoph; Sturve, Joachim; Wallin, Margareta; Svedhem, Sofia

    2013-04-01

    Organelle transport studies are often performed using melanophores from lower vertebrates due to the ease of inducing movements of pigment granules (melanosomes) and visualizing them by optical microscopy. Here, we present a novel methodology to monitor melanosome translocation (which is a light-sensitive process) in the dark using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. This acoustic sensing method was used to study dispersion and aggregation of melanosomes in Xenopus laevis melanophores. Reversible sensor responses, correlated to optical reflectance measurements, were obtained by alternating addition and removal of melatonin (leading to melanosome aggregation) and melanocyte-stimulating hormone (MSH) (leading to melanosome dispersion). By confocal microscopy, it was shown that a vertical redistribution of melanosomes occurred during the dispersion/aggregation processes. Furthermore, the transport process was studied in the presence of cytoskeleton-perturbing agents disrupting either actin filaments (latrunculin) or microtubules (nocodazole). Taken together, these experiments suggest that the acoustic responses mainly originate from melanosome transport along actin filaments (located close to the cell membrane), as expected based on the penetration depth of the QCM-D technique. The results clearly indicate the potential of QCM-D for studies of intracellular transport processes in melanophores. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Detecting Unilateral Phrenic Paralysis by Acoustic Respiratory Analysis

    Science.gov (United States)

    Fiz, José Antonio; Jané, Raimon; Lozano, Manuel; Gómez, Rosa; Ruiz, Juan

    2014-01-01

    The consequences of phrenic nerve paralysis vary from a considerable reduction in respiratory function to an apparently normal state. Acoustic analysis of lung sound intensity (LSI) could be an indirect non-invasive measurement of respiratory muscle function, comparing activity on the two sides of the thoracic cage. Lung sounds and airflow were recorded in ten males with unilateral phrenic paralysis and ten healthy subjects (5 men/5 women), during progressive increasing airflow maneuvers. Subjects were in sitting position and two acoustic sensors were placed on their back, on the left and right sides. LSI was determined from 1.2 to 2.4 L/s between 70 and 2000 Hz. LSI was significantly greater on the normal (19.3±4.0 dB) than the affected (5.7±3.5 dB) side in all patients (p = 0.0002), differences ranging from 9.9 to 21.3 dB (13.5±3.5 dB). In the healthy subjects, the LSI was similar on both left (15.1±6.3 dB) and right (17.4±5.7 dB) sides (p = 0.2730), differences ranging from 0.4 to 4.6 dB (2.3±1.6 dB). There was a positive linear relationship between the LSI and the airflow, with clear differences between the slope of patients (about 5 dB/L/s) and healthy subjects (about 10 dB/L/s). Furthermore, the LSI from the affected side of patients was close to the background noise level, at low airflows. As the airflow increases, the LSI from the affected side did also increase, but never reached the levels seen in healthy subjects. Moreover, the difference in LSI between healthy and paralyzed sides was higher in patients with lower FEV1 (%). The acoustic analysis of LSI is a relevant non-invasive technique to assess respiratory function. This method could reinforce the reliability of the diagnosis of unilateral phrenic paralysis, as well as the monitoring of these patients. PMID:24718599

  16. Effect of passive acoustic sampling methodology on detecting bats after declines from white nose syndrome

    Science.gov (United States)

    Coleman, Laci S.; Ford, W. Mark; Dobony, Christopher A.; Britzke, Eric R.

    2014-01-01

    Concomitant with the emergence and spread of white-nose syndrome (WNS) and precipitous decline of many bat species in North America, natural resource managers need modified and/or new techniques for bat inventory and monitoring that provide robust occupancy estimates. We used Anabat acoustic detectors to determine the most efficient passive acoustic sampling design for optimizing detection probabilities of multiple bat species in a WNS-impacted environment in New York, USA. Our sampling protocol included: six acoustic stations deployed for the entire duration of monitoring as well as a 4 x 4 grid and five transects of 5-10 acoustic units that were deployed for 6-8 night sample durations surveyed during the summers of 2011-2012. We used Program PRESENCE to determine detection probability and site occupancy estimates. Overall, the grid produced the highest detection probabilities for most species because it contained the most detectors and intercepted the greatest spatial area. However, big brown bats (Eptesicus fuscus) and species not impacted by WNS were detected easily regardless of sampling array. Endangered Indiana (Myotis sodalis) and little brown (Myotis lucifugus) and tri-colored bats (Perimyotis subflavus) showed declines in detection probabilities over our study, potentially indicative of continued WNS-associated declines. Identification of species presence through efficient methodologies is vital for future conservation efforts as bat populations decline further due to WNS and other factors.   

  17. Rapid Salmonella detection using an acoustic wave device combined with the RCA isothermal DNA amplification method

    Directory of Open Access Journals (Sweden)

    Antonis Kordas

    2016-12-01

    Full Text Available Salmonella enterica serovar Typhimurium is a major foodborne pathogen that causes Salmonellosis, posing a serious threat for public health and economy; thus, the development of fast and sensitive methods is of paramount importance for food quality control and safety management. In the current work, we are presenting a new approach where an isothermal amplification method is combined with an acoustic wave device for the development of a label free assay for bacteria detection. Specifically, our method utilizes a Love wave biosensor based on a Surface Acoustic Wave (SAW device combined with the isothermal Rolling Circle Amplification (RCA method; various protocols were tested regarding the DNA amplification and detection, including off-chip amplification at two different temperatures (30 °C and room temperature followed by acoustic detection and on-chip amplification and detection at room temperature, with the current detection limit being as little as 100 Bacteria Cell Equivalents (BCE/sample. Our acoustic results showed that the acoustic ratio, i.e., the amplitude over phase change observed during DNA binding, provided the only sensitive means for product detection while the measurement of amplitude or phase alone could not discriminate positive from negative samples. The method's fast analysis time together with other inherent advantages i.e., portability, potential for multi-analysis, lower sample volumes and reduced power consumption, hold great promise for employing the developed assay in a Lab on Chip (LoC platform for the integrated analysis of Salmonella in food samples. Keywords: Foodborne pathogen detection, Salmonella analysis, Rolling Circle Amplification, DNA biosensor, Lab-on-a-chip

  18. Water experiment on phased array acoustic leak detection system for sodium-heated steam generator

    International Nuclear Information System (INIS)

    Chikazawa, Yoshitaka; Yoshiuji, Takahiro

    2015-01-01

    Highlights: • An acoustic leak detection system for sodium heated steam generator is proposed. • The new system can separate leak source from steam generator background noise. • Performance of the new system has been confirmed in water experiments. - Abstract: A phased array acoustic leak detection system for sodium heated steam generator has been proposed. The major advantage of the new system is it could provide information of acoustic source direction. An acoustic source of a sodium–water reaction is supposed to be localized while the background noise of the steam generator operation is uniformly distributed in the steam generator tube region. Therefore the new system could separate the target leak source from steam generator background noise. In the previous study, the methodology was proposed and basic performance was confirmed by numerical analysis. However, in the numerical analysis, acoustic transportation through the SG tube bundle was not modeled. In the present study, performance the proposed system has been confirmed in water experiments with mockup tube bundles

  19. Experimental results of passive vibro-acoustic leak detection in SFR steam generator mock-up

    International Nuclear Information System (INIS)

    Moriot, J.; Gastaldi, O.; Maxit, L.; Guyader, J-L.; Perisse, J.; Migot, B.

    2013-06-01

    Regarding to GEN 4 context, it is necessary to fulfil the high safety standards for sodium fast reactors (SFR), particularly against water-sodium reaction which may occur in the steam generator units (SGU) in case of leak. This reaction can cause severe damages in the component in a short time. Detecting such a leak by visual in-sodium inspection is impossible because of sodium opacity. Hydrogen detection is then used but the time response of this method can be high in certain operating conditions. Active and passive acoustic leak detection methods were studied before SUPERPHENIX plant shutdown in 1997 to detect a water-into-sodium leak with a short time response. In the context of the new R and D studies for SFR, an innovative passive vibro-acoustic method is developed in the framework of a Ph.D. thesis to match with GEN 4 safety requirements. The method consists in assuming that a small leak emits spherical acoustic waves in a broadband frequency domain, which propagate in the liquid sodium and excite the SGU cylindrical shell. These spatially coherent waves are supposed to be buried by a spatially incoherent background noise. The radial velocities of the shell is measured by an array of accelerometers positioned on the external envelop of the SGU and a beam forming treatment is applied to increase the signal-to-noise ratio (SNR) and to detect and localize the acoustic source. Previous numerical experiments were achieved and promising results were obtained. In this paper, experimental results of the proposed passive vibro-acoustic leak detection are presented. The experiment consists in a cylindrical water-filled steel pipe representing a model of SGU shell without tube bundle. A hydro-phone emitting an acoustic signal is used to simulate an acoustic monopole. Spatially uncorrelated noise or water-flow induced shell vibrations are considered as the background noise. The beam-forming method is applied to vibration signals measured by a linear array of

  20. Leak detection and localization system through acoustics; Sistema de deteccao e localizacao de vazamentos por acustica

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Julio [Aselco Automacao, Sao Paulo, SP (Brazil)

    2003-07-01

    Acoustic Leak Detection Systems (ALDS) are used on both liquid and gas pipelines as well as multi-phase flow pipelines to detect leaks quickly and provide a means of limiting product loss. The real-time acoustic signal is continuously compared against signature leak profiles for the particular operating and geometric conditions. These profiles were developed from a database established from over 20 years of experimental and field leak tests. This technique not only drastically reduces the false alarm rate, but also significantly improves the sensitivity and leak location accuracy. This system will also detect leaks with shut-in flow (zero flow rate in the pipeline). With the use of GPS (Global Positioning System) it not only improves leak location accuracy, but also allows for continuous leak detection during the loss of communications. (author)

  1. Passive acoustic monitoring to detect spawning in large-bodied catostomids

    Science.gov (United States)

    Straight, Carrie A.; Freeman, Byron J.; Freeman, Mary C.

    2014-01-01

    Documenting timing, locations, and intensity of spawning can provide valuable information for conservation and management of imperiled fishes. However, deep, turbid or turbulent water, or occurrence of spawning at night, can severely limit direct observations. We have developed and tested the use of passive acoustics to detect distinctive acoustic signatures associated with spawning events of two large-bodied catostomid species (River Redhorse Moxostoma carinatum and Robust Redhorse Moxostoma robustum) in river systems in north Georgia. We deployed a hydrophone with a recording unit at four different locations on four different dates when we could both record and observe spawning activity. Recordings captured 494 spawning events that we acoustically characterized using dominant frequency, 95% frequency, relative power, and duration. We similarly characterized 46 randomly selected ambient river noises. Dominant frequency did not differ between redhorse species and ranged from 172.3 to 14,987.1 Hz. Duration of spawning events ranged from 0.65 to 11.07 s, River Redhorse having longer durations than Robust Redhorse. Observed spawning events had significantly higher dominant and 95% frequencies than ambient river noises. We additionally tested software designed to automate acoustic detection. The automated detection configurations correctly identified 80–82% of known spawning events, and falsely indentified spawns 6–7% of the time when none occurred. These rates were combined over all recordings; rates were more variable among individual recordings. Longer spawning events were more likely to be detected. Combined with sufficient visual observations to ascertain species identities and to estimate detection error rates, passive acoustic recording provides a useful tool to study spawning frequency of large-bodied fishes that displace gravel during egg deposition, including several species of imperiled catostomids.

  2. Study on Leak Detection of the Pipeline System by Acoustic Emission

    International Nuclear Information System (INIS)

    Yoon, D. J.; Kim, C. J.

    1987-01-01

    Leak detection testing for the pipeline system was performed by the acoustic emission method. It was found that the detected signal spectrum was influenced by the frequency response of sensors and pressure changes. AE parameters and frequency spectrum distributions were used to analyze the leak signals. The slope rise time of AE parameters were the important factors for distinguishing leak signals. The amplitude of leak signal was more affected by the changes of leak, rate and pressure than those of leak type

  3. Development of sensors for the acoustic detection of ultra high energy neutrinos in the deep sea

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, C.L.

    2007-09-17

    In addition to the optical detection system used by the ANTARES detector, a proposal was made to include an acoustic system consisting of several modified ANTARES storeys to investigate the feasibility of building and operating an acoustic particle detection system in the deep sea and at the same time perform an extensive study of the acoustic properties of the deep sea environment. The directional characteristics of the sensors and their placement within the ANTARES detector had to be optimised for the study of the correlation properties of the acoustic noise at different length scales - from below a metre to above 100 metres. The so-called 'equivalent circuit diagram (=ECD) model' - was applied to predict the acoustic properties of piezo elements, such as sensitivity and intrinsic noise, and was extended by including effects resulting from the geometrical shape of the sensors. A procedure was devised to gain the relevant ECD parameters from electrical impedance measurements of the piezo elements, both free and coupled to a surrounding medium. Based on the findings of this ECD model, intensive design studies were performed with prototype hydrophones using piezo elements as active sensors. The design best suited for the construction of acoustic sensors for ANTARES was determined, and a total of twelve hydrophones were built with a sensitivity of -145 to -140 dB re 1V/{mu}Pa between 5 and 50 kHz and an intrinsic noise power density around -90 dB re 1 V/{radical}(Hz), giving a total noise rms of 7 mV in this frequency range. The hydrophones were pressure tested and calibrated for integration into the ANTARES acoustic system. In addition, three so-called Acoustic Modules, sensors in pressure resistant glass spheres with a sensitive bandwidth of about 80 kHz, were developed and built. The calibration procedure employed during the sensor design studies as well as for the final sensors to be installed in the ANTARES framework is presented, together with

  4. Development of sensors for the acoustic detection of ultra high energy neutrinos in the deep sea

    International Nuclear Information System (INIS)

    Naumann, C.L.

    2007-01-01

    In addition to the optical detection system used by the ANTARES detector, a proposal was made to include an acoustic system consisting of several modified ANTARES storeys to investigate the feasibility of building and operating an acoustic particle detection system in the deep sea and at the same time perform an extensive study of the acoustic properties of the deep sea environment. The directional characteristics of the sensors and their placement within the ANTARES detector had to be optimised for the study of the correlation properties of the acoustic noise at different length scales - from below a metre to above 100 metres. The so-called ''equivalent circuit diagram (=ECD) model'' - was applied to predict the acoustic properties of piezo elements, such as sensitivity and intrinsic noise, and was extended by including effects resulting from the geometrical shape of the sensors. A procedure was devised to gain the relevant ECD parameters from electrical impedance measurements of the piezo elements, both free and coupled to a surrounding medium. Based on the findings of this ECD model, intensive design studies were performed with prototype hydrophones using piezo elements as active sensors. The design best suited for the construction of acoustic sensors for ANTARES was determined, and a total of twelve hydrophones were built with a sensitivity of -145 to -140 dB re 1V/μPa between 5 and 50 kHz and an intrinsic noise power density around -90 dB re 1 V/√(Hz), giving a total noise rms of 7 mV in this frequency range. The hydrophones were pressure tested and calibrated for integration into the ANTARES acoustic system. In addition, three so-called Acoustic Modules, sensors in pressure resistant glass spheres with a sensitive bandwidth of about 80 kHz, were developed and built. The calibration procedure employed during the sensor design studies as well as for the final sensors to be installed in the ANTARES framework is presented, together with exemplary results for

  5. Passive acoustic detection of a rebreather using a random array

    NARCIS (Netherlands)

    Fillinger, L.; Hunter, A.J.; Zampolli, M.; Clarijs, M.C.

    2013-01-01

    Divers, including closed circuit (rebreather) divers constitute a potential threat to waterside infrastructures. Active diver detection sonars are available commercially but present some shortcomings, particularly in highly reverberant environments. This has led to research on passive sonar for

  6. Ultrasonic Stimulated Acoustic Emission for Detection of Breast Microcalcifications

    National Research Council Canada - National Science Library

    Fatemi, Mostafa

    2001-01-01

    ...) for detecting microcalcifications in human breast tissue specimens. The scope of this research is to improve the laboratory USAE system and evaluate its performance on breast tissue specimens containing microcalcifications...

  7. Ultrasonic Stimulated Acoustic Emission for Detection of Breast Microcalcifications

    National Research Council Canada - National Science Library

    Fatemi, Mostafa

    2002-01-01

    ...) for detecting microcalcifications in human breast tissue specimens. The scope of this research is to develop the theory, improve the experimental USAE system, and perform USAE imaging on human breast tissue samples...

  8. Automatic Acoustic Events Detection, Classification, and Semantic Annotation for Persistent Surveillance Applications

    Science.gov (United States)

    Alkilani, Amjad H. I.

    Acoustic surveillance and human behavior analysis represent some of the ongoing research topics in signal processing. Acoustic sensors offer a promising sensing modality, primarily because they can capture a huge amount of information from the environment. Moreover, they can be rapidly deployed and are low-cost. In the past, significant efforts have been devoted to detecting sounds of individual objects or events. However, the issue of understanding human activities based on sporadic acoustic sound events has received unequal attention in the literature and hence is not well understood. This dissertation presents an extensive literature survey on this topic and discusses existing advanced techniques for acoustic signal processing and pattern recognition. A novel theoretic framework (Acoustic Events Detection, Classification, and Annotation (AEDCA)) is proposed which accommodates sound events ontology for improved human activities recognition. Based on a generalized taxonomy, three sound categories signifying interaction of human with each other, with vehicles, and with other objects are introduced. In order to understand different type of human interactions salient sound events are preliminarily identified and classified based on trained set of data. To interlink salient events representing an ontology-based hypothesis, a Hidden Markov Model-Acoustic Activity Recognizer (HMM-AAR) is modeled to recognize spatiotemporally correlated events. Once such a connection is established, an annotation of perceived sound activity is generated. The performance of the AEDCA system was tested and measured experimentally in both indoor and outdoor environments. Appropriate confusion matrices are developed for the assessment of performance reliability, and computational efficiency of the AEDCA system. The obtained results are very promising and strongly demonstrate the AEDCA is both reliable and effective, and can be extended to future surveillance applications.

  9. Surface acoustic wave sensors with Graphene/PANI nanocomposites for nitric oxide detection

    Science.gov (United States)

    Wang, Beibei; Zheng, Lei; Zhou, Lingling

    2017-12-01

    Surface acoustic wave sensors with grapheme/PANI nanocomposite sensitive films for detecting nitric oxide (NO) were fabricated and experimentally studied. Morphological characterization and functionalization of the sensing material were explored using SEM and FTIR, respectively. The study of sensor response compared film sensitivity, response time, reversibility, and limit of detection for nanocomposite films, pure grapheme and pure PANI to the detection of NO. The response and recovery times were 40s and 20s when detecting 4ppm NO, respectively. The frequency response was discovered to be linear in the NO concentration range 1-50 ppm. The nanocomposite sensors had improved sensitivities compared to the polymer devices, and better response times.

  10. Active acoustic leak detection for LMFBR steam generator. Sound attenuation due to bubbles

    International Nuclear Information System (INIS)

    Kumagai, Hiromichi; Sakuma, Toshio

    1995-01-01

    In the steam generators (SG) of LMFBR, it is necessary to detect the leakage of water from tubes of heat exchangers as soon as it occurs. The active acoustic detection method has drawn general interest owing to its short response time and reduction of the influence of background noise. In this paper, the application of the active acoustic detection method for SG is proposed, and sound attenuation by bubbles is investigated experimentally. Furthermore, using the SG sector model, sound field characteristics and sound attenuation characteristics due to injection of bubbles are studied. It is clarified that the sound attenuation depends upon bubble size as well as void fraction, that the distance attenuation of sound in the SG model containing heat transfer tubes is 6dB for each two-fold increase of distance, and that emitted sound attenuates immediately upon injection of bubbles. (author)

  11. Acoustic leak detection at complicated topologies using neural netwoks

    International Nuclear Information System (INIS)

    Hessel, G.; Schmitt, W.; Weiss, F.P.

    1994-01-01

    Considering the shortcomings of all the existing leak detecting principles, a new method again based on the measurement of the leak induced sound but also applying pattern recognition is being developed. The capability of neural networks to localize leaks at the reactor pressure vessel (RPV) head of VVER-440 reactors is discussed. (orig./DG)

  12. Surface Generated Acoustic Wave Biosensors for the Detection of Pathogens: A Review

    Directory of Open Access Journals (Sweden)

    Antonio Arnau-Vives

    2009-07-01

    Full Text Available This review presents a deep insight into the Surface Generated Acoustic Wave (SGAW technology for biosensing applications, based on more than 40 years of technological and scientific developments. In the last 20 years, SGAWs have been attracting the attention of the biochemical scientific community, due to the fact that some of these devices - Shear Horizontal Surface Acoustic Wave (SH-SAW, Surface Transverse Wave (STW, Love Wave (LW, Flexural Plate Wave (FPW, Shear Horizontal Acoustic Plate Mode (SH-APM and Layered Guided Acoustic Plate Mode (LG-APM - have demonstrated a high sensitivity in the detection of biorelevant molecules in liquid media. In addition, complementary efforts to improve the sensing films have been done during these years. All these developments have been made with the aim of achieving, in a future, a highly sensitive, low cost, small size, multi-channel, portable, reliable and commercially established SGAW biosensor. A setup with these features could significantly contribute to future developments in the health, food and environmental industries. The second purpose of this work is to describe the state-of-the-art of SGAW biosensors for the detection of pathogens, being this topic an issue of extremely importance for the human health. Finally, the review discuses the commercial availability, trends and future challenges of the SGAW biosensors for such applications.

  13. Picosecond acoustic transmission measurements. I. Transient grating generation and detection of acoustic responses in thin metal films.

    Science.gov (United States)

    Slayton, Rebecca M; Nelson, Keith A

    2004-02-22

    The technique of impulsive stimulated thermal scattering is extended to backside measurement of acoustic wave packets that have propagated through thin metal films following their generation by pulsed optical excitation, heating, and thermal expansion at the front side. The acoustic transmission measurement at the backside substantially isolates the acoustic responses from thermal and electronic responses of the metal film that often dominate acoustic reflection signals measured from the front side, and permits straightforward measurement of the acoustic response generated by optical excitation at a substrate-thin film interface. It can thus better distinguish among different factors that limit the bandwidth of the acoustic wave packet, an issue of concern in the measurement of high frequency responses. The paper that follows demonstrates the application of the backside measurement to a study of high frequency structural relaxation in the glass-forming liquid glycerol. (c) 2004 American Institute of Physics.

  14. Detection and localization of multiple wideband intermittent acoustic sources

    Science.gov (United States)

    Hudson, R. E.; Yao, K.; Hedley, R.; Taylor, C. E.

    2017-05-01

    We have been interested in the analytical and experimental study of real-life bird song sources for several years. Bird sources are characterized by either a single or multiple bird vocalizations independent of each other or in response to others. The sources may be physically-stationary or exhibit movements and the signals are wide-band in frequency and often intermittent with pauses and possibly restarting with repeating previously used songs or with new songs. Thus, the detection, classification, and 2D or 3D localization of these birds pose challenging signal and array problems. Due to the fact that some birds can mimic other birds, time-domain waveform characterization may not be sufficient for determining the number of birds. Similarly, due to the intermittent nature of the vocalizations, data collected over a long period cannot be used naively. Thus, it is necessary to use short-time Fourier transform (STFT) to fully exploit the intricate natures of the time and frequency properties of these sources and displayed on a spectrogram. Various dominant spectral data over the relevant frames are used to form sample covariance matrices. Eigenvectors associated with the decompositions of these matrices for these spectral indices can be used to provide 2D/3D DOA estimations of the sources over different frames for intermittent sources. Proper cluttering of these data can be used to perform enhanced detection, classification, and localization of multiple bird sources. Two sets of collected bird data will be used to demonstrate these claims.

  15. Alcohol detection using carbon nanotubes acoustic and optical sensors

    Science.gov (United States)

    Penza, M.; Cassano, G.; Aversa, P.; Antolini, F.; Cusano, A.; Cutolo, A.; Giordano, M.; Nicolais, L.

    2004-09-01

    We demonstrate the integration of single-walled carbon nanotubes (SWCNTs) onto quartz crystal microbalance (QCM) and standard silica optical fiber (SOF) sensor for alcohol detection at room temperature. Different transducing mechanisms have been used in order to outline the sensing properties of this class of nanomaterials, in particular the attention has been focused on two key parameters in sensing applications: mass and refractive index changes due to gas absorption. Here, Langmuir-Blodgett (LB) films consisting of tangled bundles of SWCNTs without surfactant molecules have been successfully transferred onto QCM and SOF. Mass-sensitive 10MHz QCM SWCNTs sensor exhibited a resonant frequency decreasing upon tested alcohols exposure; also the normalized optoelectronic signal (λ=1310nm) of the refractive index-sensitive SOF SWCNTs sensor was found to decrease upon alcohols ambient. Highly sensitive, repeatable and reversible responses of the QCM and SOF SWCNTs sensors indicate that the detection, at room temperature, in a wide mmHg vapor pressures range of alcohols and potentially other volatile organic compounds is feasible.

  16. Acoustic Leak Detection Testing Using KAERI Sodium-Water Reaction Signals for a SFR Steam Generator

    International Nuclear Information System (INIS)

    Kim, Tae-Joon; Jeong, Ji-Young; Kim, Jong-Man; Kim, Byung-Ho; Hahn, Do-Hee; Yugay, Valeriy S.

    2009-01-01

    The results of an experimental study of water in a sodium leak noise spectrum formation at 0.004-0.54 g/sec, various rates of water into a sodium leak, smaller than 1.0 g/sec, are presented. We focused on studying a micro leak detection with an increasing rate of water into sodium. On the basis of the experimental leak noise data manufactured in KAERI the simple dependency of an acoustic signal level from the rate of a micro and small leak at different frequency bands is presented to understand the principal analysis for the development of an acoustic leak detection methodology used in a K- 600 steam generator

  17. Hydrogen and acoustic detection in steam generators of Super Phenix power plant

    International Nuclear Information System (INIS)

    Kong, N.; Le Bris, A.; Berthier, P.

    1986-05-01

    During the isothermal tests of Super-Phenix, two types of measurements were made on the steam generators with regard to the detection of water leaks into the sodium: - the first measurements enabled us to determine the characteristics (sensitivity, response time) of the hydrogen detectors that are already operational for the filling with water and the power operation of the steam generators. They also provided the basis for developing a prototype system for detecting very small water leaks (microleak phase). The other measurements concern the qualification tests of acoustic detectors which have been fitted for the first time to a major industrial installation. The results obtained are very satisfactory but final validation of the acoustic method will only occur after the full-power tests [fr

  18. Ocean Basin Impact of Ambient Noise on Marine Mammal Detectability, Distribution, and Acoustic Communication - YIP

    Science.gov (United States)

    2014-09-30

    Detectability, Distribution, and Acoustic Communication - YIP Jennifer L. Miksis-Olds Applied Research Laboratory The Pennsylvania State University...5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Pennsylvania State University,Applied Research Laboratory ,PO...0039 to David Bradley titled “Ambient Noise Analysis from Selected CTBTO Hydroacoustic Sites”. Patterns and trends of ocean sound observed in this

  19. Acoustic detection of microbubble formation induced by enhanced optical breakdown of silver/dendrimer nanocomposites

    International Nuclear Information System (INIS)

    Milas, Susanne M.; Ye, Jing Yong; Norris, Theodore B.; Balogh, Lajos P.; Baker, James R. Jr.; Hollman, Kyle W.; Emelianov, Stanislav; O'Donnell, Matthew

    2003-01-01

    We utilize a real-time acoustic technique, based on pulse-echo measurements to detect formation of microbubbles in an aqueous solution of a silver/dendrimer nanocomposite (DNC). Wave-field plots of successive recordings illustrate the generation and behavior of bubbles created by the optical breakdown process. A significant threshold reduction is achieved with DNC particles compared to its host dendrimer, enabling a diverse field of low-threshold breakdown applications

  20. Intravascular detection of microvessel infiltration in atherosclerotic plaques: An intraluminal extension of acoustic angiography

    Science.gov (United States)

    Martin, K. Heath

    Cardiovascular disease is the leading cause of death worldwide, surpassing both stroke and cancer related mortality with 17.5 million deaths in 2014 alone. Atherosclerosis is the build-up of fatty deposits within arteries and is responsible for the majority of cardiovascular related deaths. Over the past decade, research in atherosclerosis has identified that a key limitation in the appropriate management of the disease is detecting and identifying dangerous fatty plaque build-ups before they dislodge and cause major cardiovascular events, such as embolisms, stroke, or myocardial infarctions. It has been noted that plaques vulnerable to rupture have several key features that may be used to distinguish them from asymptomatic plaques. One key identifier of a dangerous plaque is the presence of blood flow within the plaque itself since this is an indicator of growth and instability of the plaque. Recently, a superharmonic imaging method known as "acoustic angiography" has been shown to resolve microvasculature with unprecedented quality and could be a possible method of detecting blood vessel infiltration within these plaques. This dissertation describes the material and methods used to move the application of "acoustic angiography" to a reduced form factor typical of intravascular catheters and to demonstrate its ability to detect microvasculature. The implementation of this approach is described in terms of the contrast agents used to generate superharmonic signals, the dual-frequency transducers to image them, and the hardware needed to operate them in order to establish how these design choices can impact the quality of the images produced. Furthermore, this dissertation demonstrates how image processing methods such as adaptive windowing or automated sound speed correction can further enhance image quality of vascular targets. The results of these chapters show how acoustic angiography may be optimized using engineering considerations both in signal acquisition

  1. Tube leak detection device and acoustic sensor support device for moisture separating heater

    International Nuclear Information System (INIS)

    Miyabe, Keisuke; Kobayashi, Takefumi.

    1995-01-01

    The device of the present invention comprises an acoustic sensor which detects leak sounds when leak occurs in a heating tube of a moisture separating heater incorporated into a plant, a threshold value memory and switching mechanism containing each of threshold values on every power of a plant, and a leak judging mechanism for judging presence or absence of leaks by comparing a selected threshold value and signals given from the acoustic sensor. Background noises changing currently during operation of a steam turbine plant are compared with a threshold value greater than the background noises in the leak judging mechanism, and they are judged as 'no leak' so as not to recognize them as 'presence of tube leak'. Output values from the acoustic sensor are obtained on every frequency component, and standard frequency spectra are selected by turbine load corresponding signals using a standard spectra memory and switching mechanism. They are sent to a leak judging mechanism to analyze the acoustic signals using a frequency analyzer and compare them with the frequency spectral thereby judging leaks. (N.H.)

  2. Acoustic harmonic generation measurement applications: Detection of tight cracks in powder metallurgy compacts

    International Nuclear Information System (INIS)

    Barnard, D.J.; Foley, J.C.

    2000-01-01

    Standard linear ultrasonic testing techniques have long been employed for locating and characterizing relatively open cracks in a wide variety of materials, from metallic alloys and ceramics to composites. In all these materials, the detection of open cracks easily accomplished because the void between the two crack surfaces provides sufficient acoustic impedance mismatch to reflect the incident energy. Closed or partially closed cracks, however, may often go undetected because contacting interfaces allow transmission of ultrasound. In the green (unsintered) state, powder metallurgy compacts typically contain high residual stresses that have the ability to close cracks formed during the compaction process, a result of oxide films, improper powder lubricant, mold design, etc. After sintering, the reduction of residual stresses may no longer be sufficient to close the crack. Although the crack may be more easily detected, it is obvious most desirable to discover defects prior to sintering. It has been shown that the displacements of an interface may be highly nonlinear if a stress wave of sufficient intensity propagates across it, a result of the stress wave either opening or closing the interface. Current efforts involve the application of nonlinear acoustic techniques, in particular acoustic harmonic generation measurements, for the detection and characterization of tightly closed cracks in powder metallurgy parts. A description of the equipment and the measurement technique will be discussed and initial experimental results on sintered and green compacts will be presented. - This work was performed at the Ames Laboratory, Iowa State University under USDOE Contract No. W-7405-ENG-82

  3. Optimized acoustic biochip integrated with microfluidics for biomarkers detection in molecular diagnostics.

    Science.gov (United States)

    Papadakis, G; Friedt, J M; Eck, M; Rabus, D; Jobst, G; Gizeli, E

    2017-09-01

    The development of integrated platforms incorporating an acoustic device as the detection element requires addressing simultaneously several challenges of technological and scientific nature. The present work was focused on the design of a microfluidic module, which, combined with a dual or array type Love wave acoustic chip could be applied to biomedical applications and molecular diagnostics. Based on a systematic study we optimized the mechanics of the flow cell attachment and the sealing material so that fluidic interfacing/encapsulation would impose minimal losses to the acoustic wave. We have also investigated combinations of operating frequencies with waveguide materials and thicknesses for maximum sensitivity during the detection of protein and DNA biomarkers. Within our investigations neutravidin was used as a model protein biomarker and unpurified PCR amplified Salmonella DNA as the model genetic target. Our results clearly indicate the need for experimental verification of the optimum engineering and analytical parameters, in order to develop commercially viable systems for integrated analysis. The good reproducibility of the signal together with the ability of the array biochip to detect multiple samples hold promise for the future use of the integrated system in a Lab-on-a-Chip platform for application to molecular diagnostics.

  4. Detection and localization of leak of pipelines of RBMK reactor. Methods of processing of acoustic noise

    International Nuclear Information System (INIS)

    Tcherkaschov, Y.M.; Strelkov, B.P.; Chimanski, S.B.; Lebedev, V.I.; Belyanin, L.A.

    1997-01-01

    For realization of leak detection of input pipelines and output pipelines of RBMK reactor the method, based on detection and control of acoustic leak signals, was designed. In this report the review of methods of processing and analysis of acoustic noise is submitted. These methods were included in the software of the leak detection system and are used for the decision of the following problems: leak detection by method of sound pressure level in conditions of powerful background noise and strong attenuation of a signal; detection of a small leak in early stage by high-sensitivity correlation method; determination of a point of a sound source in conditions of strong reflection of a signal by a correlation method and sound pressure method; evaluation of leak size by the analysis of a sound level and point of a sound source. The work of considered techniques is illustrated on an example of test results of a fragment of the leak detection system. This test was executed on a Leningrad NPP, operated at power levels of 460, 700, 890 and 1000 MWe. 16 figs

  5. Using of acoustic technologies for detection of explosives in gas, liquid and solid medium

    International Nuclear Information System (INIS)

    Valyaev, A. N.; Yanushkevich, V.A.

    2004-01-01

    Full text: Some industrial nuclear power objects are very attractive for the realization of radiological and chemical terrorism acts with using of explosives. Although up today this type of terrorism is not revealed itself, but the problem of detection of explosives at these objects is becoming very actual one, for example, in connection with the implementation of the urgent decommissioning of nuclear powered vessels. Such decommissioning includes the utilization the dangerous radioactive and chemical elements, contained in submarines and vessels. This actual problem is existed not only in Russia, but also in abroad. It is noticed that catastrophes at these objects will have in addition the great negative mental effect on population of all over the world, as it was after the Chernobyl accident. The using of the modern nuclear physics methods for detection and analysis of explosives is connected with the following difficulties: (1) we have to have the unique and the expensive equipment; (2) the special preparation of sample probes; (3) a long time is often necessary for analysis; (4) the high qualification of service personal is needed. We proposed to use for these purposes the complex of acoustic techniques, that are based on the high sensitivity of acoustic characteristics of any matter to their physical and chemical properties.Any acoustic signal has the following main parameters: (1) frequency (ω); (2) amplitude of pressure (ρ); (3) wave and amplitude bands; (4) velocity of acoustic wave propagation (sound velocity) (C); (5) space and temporal signal evolution, that is determined by the values of coefficients of temporal attenuation (α), space adsorption (β) and sound dispersion on obstacles and impurities. Our acoustic analysis is included the determination of C, α and β values for solid and liquid explosives. The exact measurements of these parameters and their dependences from frequency and temperature are conducted in the special acoustic cells, that

  6. Acoustic leak detection at complicated geometrical structures using fuzzy logic and neural networks

    International Nuclear Information System (INIS)

    Hessel, G.; Schmitt, W.; Weiss, F.P.

    1993-10-01

    An acoustic method based on pattern recognition is being developed. During the learning phase, the localization classifier is trained with sound patterns that are generated with simulated leaks at all locations endangered by leak. The patterns are extracted from the signals of an appropriate sensor array. After training unknown leak positions can be recognized through comparison with the training patterns. The experimental part is performed at an acoustic 1:3 model of the reactor vessel and head and at an original VVER-440 reactor in the former NPP Greifswald. The leaks were simulated at the vessel head using mobile sound sources driven either by compressed air, a piezoelectric transmitter or by a thin metal blade excited through a jet of compressed air. The sound patterns of the simulated leaks are simultaneously detected with an AE-sensor array and with high frequency microphones measuring structure-borne sound and airborne sound, respectively. Pattern classifiers based on Fuzzy Pattern Classification (FPC) and Artificial Neural Networks (ANN) are currently tested for validation of the acoustic emission-sensor array (FPC), leak localization via structure-borne sound (FPC) and the leak localization using microphones (ANN). The initial results show the used classifiers principally to be capable of detecting and locating leaks, but they also show that further investigations are necessary to develop a reliable method applicable at NPPs. (orig./HP)

  7. Linear and Nonlinear Acoustic Measurements of Buried Landmines: Detection Schemes Near Resonance

    Science.gov (United States)

    Sabatier, James M.

    2003-03-01

    Measurements of the acoustic impedance of an anti-personnel and anti-tank plastic, blast-hardened landmines reveal resonances in the frequency range between 100 and 1000 Hz. The top surface resonances are due to its complicated mechanical structure vibrating in air. The lowest mode results from the blast hardened design of the landmine. Typically, a portion or cavity of the landmine is designed to absorb the shock from an explosion that is intended to detonate the landmine but still allow the landmine to trigger its explosive device when a slow steady pressure is applied. The mechanical design of the blast hardened aspects results in a high Q simple harmonic oscillator resonance of the top surface. At higher frequencies the top surface behaves like thin circular plate acoustic modes. When these landmines are buried in soils, the modes are mass loaded. Resonances from measurements of the normal component of the acoustically induced soil surface particle velocity are used for detection schemes. Since the interface between the top plate and the soil responds to pressure fluctuations nonlinearly, characteristics of landmines, the soil, and the interface are rich in nonlinear physics and allow for new methods of landmine detection not previously exploited.

  8. Automated acoustic analysis in detection of spontaneous swallows in Parkinson's disease.

    Science.gov (United States)

    Golabbakhsh, Marzieh; Rajaei, Ali; Derakhshan, Mahmoud; Sadri, Saeed; Taheri, Masoud; Adibi, Peyman

    2014-10-01

    Acoustic monitoring of swallow frequency has become important as the frequency of spontaneous swallowing can be an index for dysphagia and related complications. In addition, it can be employed as an objective quantification of ingestive behavior. Commonly, swallowing complications are manually detected using videofluoroscopy recordings, which require expensive equipment and exposure to radiation. In this study, a noninvasive automated technique is proposed that uses breath and swallowing recordings obtained via a microphone located over the laryngopharynx. Nonlinear diffusion filters were used in which a scale-space decomposition of recorded sound at different levels extract swallows from breath sounds and artifacts. This technique was compared to manual detection of swallows using acoustic signals on a sample of 34 subjects with Parkinson's disease. A speech language pathologist identified five subjects who showed aspiration during the videofluoroscopic swallowing study. The proposed automated method identified swallows with a sensitivity of 86.67 %, a specificity of 77.50 %, and an accuracy of 82.35 %. These results indicate the validity of automated acoustic recognition of swallowing as a fast and efficient approach to objectively estimate spontaneous swallow frequency.

  9. Mach-Zehnder interferometric photonic crystal fiber for low acoustic frequency detections

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, Dnyandeo; Rao, Ch. N.; Kale, S. N., E-mail: sangeetakale2004@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411 025, Maharashtra (India); Choubey, Ravi Kant [Department of Applied Physics, Amity Institute of Applied Sciences, Amity University, Noida 201 313 (India)

    2016-01-25

    Low frequency under-water acoustic signal detections are challenging, especially for marine applications. A Mach-Zehnder interferometric hydrophone is demonstrated using polarization-maintaining photonic-crystal-fiber (PM-PCF), spliced between two single-mode-fibers, operated at 1550 nm source. These data are compared with standard hydrophone, single-mode and multimode fiber. The PM-PCF sensor shows the highest response with a power shift (2.32 dBm) and a wavelength shift (392.8 pm) at 200 Hz. High birefringence values and the effect of the imparted acoustic pressure on this fiber, introducing the difference between the fast and slow axis changes, owing to the phase change in the propagation waves, demonstrate the strain-optic properties of the sensor.

  10. Passive Acoustic Leak Detection for Sodium Cooled Fast Reactors Using Hidden Markov Models

    Science.gov (United States)

    Marklund, A. Riber; Kishore, S.; Prakash, V.; Rajan, K. K.; Michel, F.

    2016-06-01

    Acoustic leak detection for steam generators of sodium fast reactors have been an active research topic since the early 1970s and several methods have been tested over the years. Inspired by its success in the field of automatic speech recognition, we here apply hidden Markov models (HMM) in combination with Gaussian mixture models (GMM) to the problem. To achieve this, we propose a new feature calculation scheme, based on the temporal evolution of the power spectral density (PSD) of the signal. Using acoustic signals recorded during steam/water injection experiments done at the Indira Gandhi Centre for Atomic Research (IGCAR), the proposed method is tested. We perform parametric studies on the HMM+GMM model size and demonstrate that the proposed method a) performs well without a priori knowledge of injection noise, b) can incorporate several noise models and c) has an output distribution that simplifies false alarm rate control.

  11. A Miniaturized QEPAS Trace Gas Sensor with a 3D-Printed Acoustic Detection Module

    Directory of Open Access Journals (Sweden)

    Xiaotao Yang

    2017-07-01

    Full Text Available A 3D printing technique was introduced to a quartz-enhanced photoacoustic spectroscopy (QEPAS sensor and is reported for the first time. The acoustic detection module (ADM was designed and fabricated using the 3D printing technique and the ADM volume was compressed significantly. Furthermore, a small grin lens was used for laser focusing and facilitated the beam adjustment in the 3D-printed ADM. A quartz tuning fork (QTF with a low resonance frequency of 30.72 kHz was used as the acoustic wave transducer and acetylene (C2H2 was chosen as the analyte. The reported miniaturized QEPAS trace gas sensor is useful in actual sensor applications.

  12. Streptavidin Modified ZnO Film Bulk Acoustic Resonator for Detection of Tumor Marker Mucin 1

    Science.gov (United States)

    Zheng, Dan; Guo, Peng; Xiong, Juan; Wang, Shengfu

    2016-09-01

    A ZnO-based film bulk acoustic resonator has been fabricated using a magnetron sputtering technology, which was employed as a biosensor for detection of mucin 1. The resonant frequency of the thin-film bulk acoustic resonator was located near at 1503.3 MHz. The average electromechanical coupling factor {K}_{eff}^2 and quality factor Q were 2.39 % and 224, respectively. Using the specific binding system of avidin-biotin, the streptavidin was self-assembled on the top gold electrode as the sensitive layer to indirectly test the MUC1 molecules. The resonant frequency of the biosensor decreases in response to the mass loading in range of 20-500 nM. The sensor modified with the streptavidin exhibits a high sensitivity of 4642.6 Hz/nM and a good selectivity.

  13. Detection of ductile crack initiation by acoustic emission testing; Detektion von duktiler Rissinitiierung durch Schallemissionen

    Energy Technology Data Exchange (ETDEWEB)

    Richter, H.; Boehmert, J.; Viehrig, H.W. [Forschungszentrum Rossendorf e.V. (FZR) (Germany). Inst. fuer Sicherheitsforschung; Valo, M. [VTT Manufacturing Technology, Materials and Structural Integrity, Espoo (Finland)

    1998-08-01

    A Charpy impact test equipment is described permitting simultaneous measurement of impact force, crack tip opening, acoustic emissions and magnetic emissions. The core of the equipment is an inverted pendulum ram impact testing machine and the tests have been performed with laterally notched, pre-fatigue ISO-V specimens made of steels of various strength and tougness properties. The tests are intended to ascertain whether the acoustic emission method is suitable for detecting steady crack initiation in highly ductile steels. (orig./CB) [Deutsch] Es wird eine Kerbschlagbiegeanordnung vorgestellt, mit der simultan Schlagkraft, Rissoeffnung, Schallemission und magnetische Emission gemessen werden koennen. Grundbaustein der Anordnung ist ein invertiertes Pendelschlagwerk. Mit dieser Anordnung wurden seitgekerbte, vorermuedete ISO-V Proben aus Staehlen mit unterschiedlichen Festigkeits-Zaehigkeitseigenschaften geprueft. Die Untersuchung soll aufzeigen, ob Schallemission zur Detektion der stabilen Rissinitierung an hochzaehen Staehlen geeignet ist. (orig./CB)

  14. Passive acoustic leak detection for sodium cooled fast reactors using hidden Markov models

    Energy Technology Data Exchange (ETDEWEB)

    Riber Marklund, A. [CEA, Cadarache, DEN/DTN/STCP/LIET, Batiment 202, 13108 St Paul-lez-Durance, (France); Kishore, S. [Fast Reactor Technology Group of IGCAR, (India); Prakash, V. [Vibrations Diagnostics Division, Fast Reactor Technology Group of IGCAR, (India); Rajan, K.K. [Fast Reactor Technology Group and Engineering Services Group of IGCAR, (India)

    2015-07-01

    Acoustic leak detection for steam generators of sodium fast reactors have been an active research topic since the early 1970's and several methods have been tested over the years. Inspired by its success in the field of automatic speech recognition, we here apply hidden Markov models (HMM) in combination with Gaussian mixture models (GMM) to the problem. To achieve this, we propose a new feature calculation scheme, based on the temporal evolution of the power spectral density (PSD) of the signal. Using acoustic signals recorded during steam/water injection experiments done at the Indira Gandhi Centre for Atomic Research (IGCAR), the proposed method is tested. We perform parametric studies on the HMM+GMM model size and demonstrate that the proposed method a) performs well without a priori knowledge of injection noise, b) can incorporate several noise models and c) has an output distribution that simplifies false alarm rate control. (authors)

  15. Acoustical analysis of mechanical heart valve sounds for early detection of malfunction.

    Science.gov (United States)

    Famaey, Nele; Defever, Korijn; Bielen, Paul; Flameng, Willem; Vander Sloten, Jos; Sas, Paul; Meuris, Bart

    2010-10-01

    Mechanical heart valves carry the disadvantage of lifelong antithrombotic therapy, due to the high risk of thrombus formation on the valve surface. Current diagnostic methods are incapable of detecting thrombus formation in an early stage. This article investigates a new diagnostic method, based on the analysis of the acoustic signal produced by the valve. This method should be capable of early detection of malfunction, thus permitting targeted medication and reducing valve-related complications and mortality. A measurement setup assuring optimal signal quality was developed, and a signal analysis program was implemented and validated on an in vitro mock circulatory loop. Next, four sheep were implanted with a bileaflet mechanical valve. The signals of their valves developing thrombosis were assessed on a weekly basis before explantation. Three sheep were sacrificed shortly after detection of malfunction according to the newly developed method. In each case, thrombus or membrane formation was detected on the leaflets upon explantation. In one sheep, no malfunction was found in the analysis, which was also confirmed by the condition of the valve upon explantation. These preliminary results indicate that acoustical analysis of mechanical heart valves permits early detection of valvular malfunction. Further research with more in vitro and animal testing is required to statistically validate these findings. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. Critical heat flux acoustic detection: Methods and application to ITER divertor vertical target monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Courtois, X., E-mail: xavier.courtois@cea.fr [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Escourbiac, F. [ITER Organization, Route de Vinon sur Verdon, F-13115 Saint-Paul-Lez-Durance (France); Richou, M.; Cantone, V. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Constans, S. [AREVA-NP, Le Creusot (France)

    2013-10-15

    Actively cooled plasma facing components (PFCs) have to exhaust high heat fluxes from plasma radiation and plasma–wall interaction. Critical heat flux (CHF) event may occur in the cooling channel due to unexpected heat loading or operational conditions, and has to be detected as soon as possible. Therefore it is essential to develop means of monitoring based on precursory signals providing an early detection of this destructive phenomenon, in order to be able to stop operation before irremediable damages appear. Capabilities of CHF early detection based on acoustic techniques on PFC mock-ups cooled by pressurised water were already demonstrated. This paper addresses the problem of the detection in case of flow rate reduction and of flow dilution resulting from multiple plasma facing units (PFU) which are hydraulically connected in parallel, which is the case of ITER divertor. An experimental study is launched on a dedicated mock-up submitted to heat loads up to the CHF. It shows that the measurement of the acoustic waves, generated by the cooling phenomena, allows the CHF detection in conditions similar to that of the ITER divertor, with a reasonable number of sensors. The paper describes the mock-ups and the tests sequences, and comments the results.

  17. Automated valve fault detection based on acoustic emission parameters and support vector machine

    Directory of Open Access Journals (Sweden)

    Salah M. Ali

    2018-03-01

    Full Text Available Reciprocating compressors are one of the most used types of compressors with wide applications in industry. The most common failure in reciprocating compressors is always related to the valves. Therefore, a reliable condition monitoring method is required to avoid the unplanned shutdown in this category of machines. Acoustic emission (AE technique is one of the effective recent methods in the field of valve condition monitoring. However, a major challenge is related to the analysis of AE signal which perhaps only depends on the experience and knowledge of technicians. This paper proposes automated fault detection method using support vector machine (SVM and AE parameters in an attempt to reduce human intervention in the process. Experiments were conducted on a single stage reciprocating air compressor by combining healthy and faulty valve conditions to acquire the AE signals. Valve functioning was identified through AE waveform analysis. SVM faults detection model was subsequently devised and validated based on training and testing samples respectively. The results demonstrated automatic valve fault detection model with accuracy exceeding 98%. It is believed that valve faults can be detected efficiently without human intervention by employing the proposed model for a single stage reciprocating compressor. Keywords: Condition monitoring, Faults detection, Signal analysis, Acoustic emission, Support vector machine

  18. Cetacean acoustic detections from free-floating vertical hydrophone arrays in the southern California Current.

    Science.gov (United States)

    Griffiths, Emily T; Barlow, Jay

    2016-11-01

    Drifting acoustic recorders were deployed in the southern California Current during Fall 2014. Two hydrophones configured as a 2-m vertical array at 100 m depth recorded using a 192 kHz sample rate on a 10% duty cycle (2 min/20 min). Beaked whales were detected in 33 of 8618 two-minute recordings. Sperm whales were detected in 185 recordings, and dolphins in 2291 recordings. Many beaked whales detected were over an abyssal plain and not associated with slope or seamount features. Results show the feasibility of using free-floating recording systems to detect a variety of cetacean species over periods of several months.

  19. FAULT DETECTION AND LOCALIZATION IN MOTORCYCLES BASED ON THE CHAIN CODE OF PSEUDOSPECTRA AND ACOUSTIC SIGNALS

    Directory of Open Access Journals (Sweden)

    B. S. Anami

    2013-06-01

    Full Text Available Vehicles produce sound signals with varying temporal and spectral properties under different working conditions. These sounds are indicative of the condition of the engine. Fault diagnosis is a significantly difficult task in geographically remote places where expertise is scarce. Automated fault diagnosis can assist riders to assess the health condition of their vehicles. This paper presents a method for fault detection and location in motorcycles based on the chain code of the pseudospectra and Mel-frequency cepstral coefficient (MFCC features of acoustic signals. The work comprises two stages: fault detection and fault location. The fault detection stage uses the chain code of the pseudospectrum as a feature vector. If the motorcycle is identified as faulty, the MFCCs of the same sample are computed and used as features for fault location. Both stages employ dynamic time warping for the classification of faults. Five types of faults in motorcycles are considered in this work. Observed classification rates are over 90% for the fault detection stage and over 94% for the fault location stage. The work identifies other interesting applications in the development of acoustic fingerprints for fault diagnosis of machinery, tuning of musical instruments, medical diagnosis, etc.

  20. Detection of Volatile Organics Using a Surface Acoustic Wave Array System

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON, LAWRENCE F.; BARTHOLOMEW, JOHN W.; CERNOSEK, RICHARD W.; COLBURN, CHRISTOPHER W.; CROOKS, R.M.; MARTINEZ, R.F.; OSBOURN, GORDON C.; RICCO, A.J.; STATON, ALAN W.; YELTON, WILLIAM G.

    1999-10-14

    A chemical sensing system based on arrays of surface acoustic wave (SAW) delay lines has been developed for identification and quantification of volatile organic compounds (VOCs). The individual SAW chemical sensors consist of interdigital transducers patterned on the surface of an ST-cut quartz substrate to launch and detect the acoustic waves and a thin film coating in the SAW propagation path to perturb the acoustic wave velocity and attenuation during analyte sorption. A diverse set of material coatings gives the sensor arrays a degree of chemical sensitivity and selectivity. Materials examined for sensor application include the alkanethiol-based self-assembled monolayer, plasma-processed films, custom-synthesized conventional polymers, dendrimeric polymers, molecular recognition materials, electroplated metal thin films, and porous metal oxides. All of these materials target a specific chemical fi.mctionality and the enhancement of accessible film surface area. Since no one coating provides absolute analyte specificity, the array responses are further analyzed using a visual-empirical region-of-influence (VERI) pattern recognition algorithm. The chemical sensing system consists of a seven-element SAW array with accompanying drive and control electronics, sensor signal acquisition electronics, environmental vapor sampling hardware, and a notebook computer. Based on data gathered for individual sensor responses, greater than 93%-accurate identification can be achieved for any single analyte from a group of 17 VOCs and water.

  1. Shear horizontal surface acoustic wave microsensor for Class A viral and bacterial detection.

    Energy Technology Data Exchange (ETDEWEB)

    Branch, Darren W.; Huber, Dale L.; Brozik, Susan Marie; Edwards, Thayne L.

    2008-10-01

    The rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms is critical to human health and safety. To achieve a high level of sensitivity for fluidic detection applications, we have developed a 330 MHz Love wave acoustic biosensor on 36{sup o} YX Lithium Tantalate (LTO). Each die has four delay-line detection channels, permitting simultaneous measurement of multiple analytes or for parallel detection of single analyte containing samples. Crucial to our biosensor was the development of a transducer that excites the shear horizontal (SH) mode, through optimization of the transducer, minimizing propagation losses and reducing undesirable modes. Detection was achieved by comparing the reference phase of an input signal to the phase shift from the biosensor using an integrated electronic multi-readout system connected to a laptop computer or PDA. The Love wave acoustic arrays were centered at 330 MHz, shifting to 325-328 MHz after application of the silicon dioxide waveguides. The insertion loss was -6 dB with an out-of-band rejection of 35 dB. The amplitude and phase ripple were 2.5 dB p-p and 2-3{sup o} p-p, respectively. Time-domain gating confirmed propagation of the SH mode while showing suppression of the triple transit. Antigen capture and mass detection experiments demonstrate a sensitivity of 7.19 {+-} 0.74{sup o} mm{sup 2}/ng with a detection limit of 6.7 {+-} 0.40 pg/mm{sup 2} for each channel.

  2. Acoustic leak-detection/location system with multichannel charge amplifier/line driver

    International Nuclear Information System (INIS)

    Gaubatz, D.C.; Greene, D.A.

    1980-04-01

    Testing on the MATOI test vessel was initiated using a multichannel Acoustic Leak Detection System (ALDS). The multichannel system incorporates several key elements of the reference ALDS: prototypic multichannel charge amplifiers; computer controlled multiplexer; computer controlled gain amplifiers; and alarm annunciation. ALDS now has prototypic analogue signal conditioning identical to that proposed for an LMFBR system. Beamforming and digital signal analysis hardware are simulated by a software program in the PDP 11 minicomputer. Comparative performance data are provided between the prototypic and earlier versions

  3. Detection of the onset of galling in strip reduction testing using acoustic emission

    DEFF Research Database (Denmark)

    Moghadam, Marcel; Christiansen, Peter; Bay, Niels Oluf

    2017-01-01

    to detect, since it is either based on the operator's personal judgement or indirect measuring techniques. The application of acoustic emission measuring technique for characterization of onset of galling in sheet metal forming is discussed in the presented paper. The strip reduction test, which emulates......Galling is an important issue in metal forming of tribologically severe materials such as high strength steel, stainless steel, Al- or Ti-alloys, since it leads to poor surface quality of the formed components, production stops and possibly deterioration of tools. The onset of galling is difficult...... of galling in metal forming processes....

  4. Acoustic Methods to Monitor Protein Crystallization and to Detect Protein Crystals in Suspensions of Agarose and Lipidic Cubic Phase

    Energy Technology Data Exchange (ETDEWEB)

    Ericson, Daniel L.; Yin, Xingyu; Scalia, Alexander; Samara, Yasmin N.; Stearns, Richard; Vlahos, Harry; Ellson, Richard; Sweet, Robert M.; Soares, Alexei S.

    2016-02-01

    Improvements needed for automated crystallography include crystal detection and crystal harvesting. A technique that uses acoustic droplet ejection to harvest crystals was previously reported. Here a method is described for using the same acoustic instrument to detect protein crystals and to monitor crystal growth. Acoustic pulses were used to monitor the progress of crystallization trials and to detect the presence and location of protein crystals. Crystals were detected, and crystallization was monitored in aqueous solutions and in lipidic cubic phase. Using a commercially available acoustic instrument, crystals measuring ~150 µm or larger were readily detected. Simple laboratory techniques were used to increase the sensitivity to 50 µm by suspending the crystals away from the plastic surface of the crystallization plate. This increased the sensitivity by separating the strong signal generated by the plate bottom that can mask the signal from small protein crystals. It is possible to further boost the acoustic reflection from small crystals by reducing the wavelength of the incident sound pulse, but our current instrumentation does not allow this option. In the future, commercially available sound-emitting transducers with a characteristic frequency near 300 MHz should detect and monitor the growth of individual 3 µm crystals.

  5. Acoustic Methods to Monitor Protein Crystallization and to Detect Protein Crystals in Suspensions of Agarose and Lipidic Cubic Phase.

    Science.gov (United States)

    Ericson, Daniel L; Yin, Xingyu; Scalia, Alexander; Samara, Yasmin N; Stearns, Richard; Vlahos, Harry; Ellson, Richard; Sweet, Robert M; Soares, Alexei S

    2016-02-01

    Improvements needed for automated crystallography include crystal detection and crystal harvesting. A technique that uses acoustic droplet ejection to harvest crystals was previously reported. Here a method is described for using the same acoustic instrument to detect protein crystals and to monitor crystal growth. Acoustic pulses were used to monitor the progress of crystallization trials and to detect the presence and location of protein crystals. Crystals were detected, and crystallization was monitored in aqueous solutions and in lipidic cubic phase. Using a commercially available acoustic instrument, crystals measuring ~150 µm or larger were readily detected. Simple laboratory techniques were used to increase the sensitivity to 50 µm by suspending the crystals away from the plastic surface of the crystallization plate. This increased the sensitivity by separating the strong signal generated by the plate bottom that can mask the signal from small protein crystals. It is possible to further boost the acoustic reflection from small crystals by reducing the wavelength of the incident sound pulse, but our current instrumentation does not allow this option. In the future, commercially available sound-emitting transducers with a characteristic frequency near 300 MHz should detect and monitor the growth of individual 3 µm crystals. © 2015 Society for Laboratory Automation and Screening.

  6. Deep Recurrent Neural Network-Based Autoencoders for Acoustic Novelty Detection

    Directory of Open Access Journals (Sweden)

    Erik Marchi

    2017-01-01

    Full Text Available In the emerging field of acoustic novelty detection, most research efforts are devoted to probabilistic approaches such as mixture models or state-space models. Only recent studies introduced (pseudo-generative models for acoustic novelty detection with recurrent neural networks in the form of an autoencoder. In these approaches, auditory spectral features of the next short term frame are predicted from the previous frames by means of Long-Short Term Memory recurrent denoising autoencoders. The reconstruction error between the input and the output of the autoencoder is used as activation signal to detect novel events. There is no evidence of studies focused on comparing previous efforts to automatically recognize novel events from audio signals and giving a broad and in depth evaluation of recurrent neural network-based autoencoders. The present contribution aims to consistently evaluate our recent novel approaches to fill this white spot in the literature and provide insight by extensive evaluations carried out on three databases: A3Novelty, PASCAL CHiME, and PROMETHEUS. Besides providing an extensive analysis of novel and state-of-the-art methods, the article shows how RNN-based autoencoders outperform statistical approaches up to an absolute improvement of 16.4% average F-measure over the three databases.

  7. Acoustic Emission Monitoring of Incipient in Journal Bearings - Part I : Detectability and measurement for bearing damages

    International Nuclear Information System (INIS)

    Yoon, Dong Jin; Kwon, Oh Yang; Chung, Min Hwa; Kim, Kyung Woong

    1994-01-01

    In contrast to the machinery using rolling element bearings, systems with journal bearings generally operate in large scale and under severe loading condition such as steam generator turbines and internal combustion engines. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is applied to the detection of incipient failure caused by several types of abnormal operating condition most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as hard particles in the lubrication layer, insufficient lubrication, and metallic contact in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings

  8. Deep Recurrent Neural Network-Based Autoencoders for Acoustic Novelty Detection.

    Science.gov (United States)

    Marchi, Erik; Vesperini, Fabio; Squartini, Stefano; Schuller, Björn

    2017-01-01

    In the emerging field of acoustic novelty detection, most research efforts are devoted to probabilistic approaches such as mixture models or state-space models. Only recent studies introduced (pseudo-)generative models for acoustic novelty detection with recurrent neural networks in the form of an autoencoder. In these approaches, auditory spectral features of the next short term frame are predicted from the previous frames by means of Long-Short Term Memory recurrent denoising autoencoders. The reconstruction error between the input and the output of the autoencoder is used as activation signal to detect novel events. There is no evidence of studies focused on comparing previous efforts to automatically recognize novel events from audio signals and giving a broad and in depth evaluation of recurrent neural network-based autoencoders. The present contribution aims to consistently evaluate our recent novel approaches to fill this white spot in the literature and provide insight by extensive evaluations carried out on three databases: A3Novelty, PASCAL CHiME, and PROMETHEUS. Besides providing an extensive analysis of novel and state-of-the-art methods, the article shows how RNN-based autoencoders outperform statistical approaches up to an absolute improvement of 16.4% average F -measure over the three databases.

  9. Nondestructive Online Detection of Welding Defects in Track Crane Boom Using Acoustic Emission Technique

    Directory of Open Access Journals (Sweden)

    Yong Tao

    2014-04-01

    Full Text Available Nondestructive detection of structural component of track crane is a difficult and costly problem. In the present study, acoustic emission (AE was used to detect two kinds of typical welding defects, that is, welding porosity and incomplete penetration, in the truck crane boom. Firstly, a subsidiary test specimen with special preset welding defect was designed and added on the boom surface with the aid of steel plates to get the synchronous deformation of the main boom. Then, the AE feature information of the welding defect could be got without influencing normal operation of equipment. As a result, the rudimentary location analysis can be attained using the linear location method and the two kinds of welding defects can be distinguished clearly using AE characteristic parameters such as amplitude and centroid frequency. Also, through the comparison of two loading processes, we concluded that the signal produced during the first loading process was mainly caused by plastic deformation damage and during the second loading process the stress release and structure friction between sections in welding area are the main acoustic emission sources. Thus, the AE is an available tool for nondestructive online detection of latent welding defects of structural component of track crane.

  10. A Fiber-Optic Sensor for Acoustic Emission Detection in a High Voltage Cable System

    Science.gov (United States)

    Zhang, Tongzhi; Pang, Fufei; Liu, Huanhuan; Cheng, Jiajing; Lv, Longbao; Zhang, Xiaobei; Chen, Na; Wang, Tingyun

    2016-01-01

    We have proposed and demonstrated a Michelson interferometer-based fiber sensor for detecting acoustic emission generated from the partial discharge (PD) of the accessories of a high-voltage cable system. The developed sensor head is integrated with a compact and relatively high sensitivity cylindrical elastomer. Such a sensor has a broadband frequency response and a relatively high sensitivity in a harsh environment under a high-voltage electric field. The design and fabrication of the sensor head integrated with the cylindrical elastomer is described, and a series of experiments was conducted to evaluate the sensing performance. The experimental results demonstrate that the sensitivity of our developed sensor for acoustic detection of partial discharges is 1.7 rad/(m⋅Pa). A high frequency response up to 150 kHz is achieved. Moreover, the relatively high sensitivity for the detection of PD is verified in both the laboratory environment and gas insulated switchgear. The obtained results show the great potential application of a Michelson interferometer-based fiber sensor integrated with a cylindrical elastomer for in-situ monitoring high-voltage cable accessories for safety work. PMID:27916900

  11. The detection of formaldehyde using microelectromechanical acoustic resonator with multiwalled carbon nanotubes-polyethyleneimine composite coating

    Science.gov (United States)

    Wang, Jingjing; Zhan, Da; Wang, Ke; Hang, Weiwei

    2018-01-01

    A micro-scale gas sensor based on mass-sensitive film bulk acoustic resonator is demonstrated for the detection of trace formaldehyde at room temperature. The composites mixed with multiwalled carbon nanotubes and polyethyleneimine (MWNTs-PEI) were coated on the resonator surface as the sensitive layer to specifically absorb formaldehyde molecules using a facile spray process. The influence of spraying processes on the formaldehyde sensing properties were investigated. Different response behaviors were determined by both the chemical absorption between formaldehyde molecules and the amine functional groups on PEI and the increase of absorption surface came from the nanostructure. The combination of high frequency of the film bulk acoustic resonator (~4.3 GHz) and the specific absorbability of MWNTs-PEI composites provided a high sensitivity in the detections of trace formaldehyde. The obtained ultra-low limit of detection was as low as 60 ppb with linear response, quick response/recovery time, good reproducibility and selectivity. The proposed sensor shows potential as a portable and convenient gas-sensing system for monitoring the low-level concentration of indoor air pollution.

  12. A real-time method for autonomous passive acoustic detection-classification of humpback whales.

    Science.gov (United States)

    Abbot, Ted A; Premus, Vincent E; Abbot, Philip A

    2010-05-01

    This paper describes a method for real-time, autonomous, joint detection-classification of humpback whale vocalizations. The approach adapts the spectrogram correlation method used by Mellinger and Clark [J. Acoust. Soc. Am. 107, 3518-3529 (2000)] for bowhead whale endnote detection to the humpback whale problem. The objective is the implementation of a system to determine the presence or absence of humpback whales with passive acoustic methods and to perform this classification with low false alarm rate in real time. Multiple correlation kernels are used due to the diversity of humpback song. The approach also takes advantage of the fact that humpbacks tend to vocalize repeatedly for extended periods of time, and identification is declared only when multiple song units are detected within a fixed time interval. Humpback whale vocalizations from Alaska, Hawaii, and Stellwagen Bank were used to train the algorithm. It was then tested on independent data obtained off Kaena Point, Hawaii in February and March of 2009. Results show that the algorithm successfully classified humpback whales autonomously in real time, with a measured probability of correct classification in excess of 74% and a measured probability of false alarm below 1%.

  13. A Fiber-Optic Sensor for Acoustic Emission Detection in a High Voltage Cable System

    Directory of Open Access Journals (Sweden)

    Tongzhi Zhang

    2016-11-01

    Full Text Available We have proposed and demonstrated a Michelson interferometer-based fiber sensor for detecting acoustic emission generated from the partial discharge (PD of the accessories of a high-voltage cable system. The developed sensor head is integrated with a compact and relatively high sensitivity cylindrical elastomer. Such a sensor has a broadband frequency response and a relatively high sensitivity in a harsh environment under a high-voltage electric field. The design and fabrication of the sensor head integrated with the cylindrical elastomer is described, and a series of experiments was conducted to evaluate the sensing performance. The experimental results demonstrate that the sensitivity of our developed sensor for acoustic detection of partial discharges is 1.7 rad / ( m ⋅ Pa . A high frequency response up to 150 kHz is achieved. Moreover, the relatively high sensitivity for the detection of PD is verified in both the laboratory environment and gas insulated switchgear. The obtained results show the great potential application of a Michelson interferometer-based fiber sensor integrated with a cylindrical elastomer for in-situ monitoring high-voltage cable accessories for safety work.

  14. Assisting the Visually Impaired: Obstacle Detection and Warning System by Acoustic Feedback

    Directory of Open Access Journals (Sweden)

    Andrés Cela

    2012-12-01

    Full Text Available The aim of this article is focused on the design of an obstacle detection system for assisting visually impaired people. A dense disparity map is computed from the images of a stereo camera carried by the user. By using the dense disparity map, potential obstacles can be detected in 3D in indoor and outdoor scenarios. A ground plane estimation algorithm based on RANSAC plus filtering techniques allows the robust detection of the ground in every frame. A polar grid representation is proposed to account for the potential obstacles in the scene. The design is completed with acoustic feedback to assist visually impaired users while approaching obstacles. Beep sounds with different frequencies and repetitions inform the user about the presence of obstacles. Audio bone conducting technology is employed to play these sounds without interrupting the visually impaired user from hearing other important sounds from its local environment. A user study participated by four visually impaired volunteers supports the proposed system.

  15. Assisting the visually impaired: obstacle detection and warning system by acoustic feedback.

    Science.gov (United States)

    Rodríguez, Alberto; Yebes, J Javier; Alcantarilla, Pablo F; Bergasa, Luis M; Almazán, Javier; Cela, Andrés

    2012-12-17

    The aim of this article is focused on the design of an obstacle detection system for assisting visually impaired people. A dense disparity map is computed from the images of a stereo camera carried by the user. By using the dense disparity map, potential obstacles can be detected in 3D in indoor and outdoor scenarios. A ground plane estimation algorithm based on RANSAC plus filtering techniques allows the robust detection of the ground in every frame. A polar grid representation is proposed to account for the potential obstacles in the scene. The design is completed with acoustic feedback to assist visually impaired users while approaching obstacles. Beep sounds with different frequencies and repetitions inform the user about the presence of obstacles. Audio bone conducting technology is employed to play these sounds without interrupting the visually impaired user from hearing other important sounds from its local environment. A user study participated by four visually impaired volunteers supports the proposed system.

  16. Snapping shrimp noise mitigation based on statistical detection in underwater acoustic orthogonal frequency division multiplexing systems

    Science.gov (United States)

    Kim, Hyeonsu; Seo, Jongpil; Ahn, Jongmin; Chung, Jaehak

    2017-07-01

    We propose a mitigation scheme for snapping shrimp noise when it corrupts an orthogonal frequency division multiplexing (OFDM) signal in underwater acoustic communication systems. The OFDM signal distorted by the snapping shrimp noise is filtered by a band-stop filter. The snapping shrimp noises in the filtered signal are detected by a detector with a constant false alarm rate whose threshold is derived theoretically from the statistics of the background noise. The detected signals are reconstructed by a simple reconstruction method. The proposed scheme has a higher detection capability and a lower mean square error of the channel estimation for simulated data and a lower bit error rate for practical ocean OFDM data collected in northern East China Sea than the conventional noise-mitigating methods.

  17. To see or not to see: investigating detectability of Ganges River dolphins using a combined visual-acoustic survey.

    Science.gov (United States)

    Richman, Nadia I; Gibbons, James M; Turvey, Samuel T; Akamatsu, Tomonari; Ahmed, Benazir; Mahabub, Emile; Smith, Brian D; Jones, Julia P G

    2014-01-01

    Detection of animals during visual surveys is rarely perfect or constant, and failure to account for imperfect detectability affects the accuracy of abundance estimates. Freshwater cetaceans are among the most threatened group of mammals, and visual surveys are a commonly employed method for estimating population size despite concerns over imperfect and unquantified detectability. We used a combined visual-acoustic survey to estimate detectability of Ganges River dolphins (Platanista gangetica gangetica) in four waterways of southern Bangladesh. The combined visual-acoustic survey resulted in consistently higher detectability than a single observer-team visual survey, thereby improving power to detect trends. Visual detectability was particularly low for dolphins close to meanders where these habitat features temporarily block the view of the preceding river surface. This systematic bias in detectability during visual-only surveys may lead researchers to underestimate the importance of heavily meandering river reaches. Although the benefits of acoustic surveys are increasingly recognised for marine cetaceans, they have not been widely used for monitoring abundance of freshwater cetaceans due to perceived costs and technical skill requirements. We show that acoustic surveys are in fact a relatively cost-effective approach for surveying freshwater cetaceans, once it is acknowledged that methods that do not account for imperfect detectability are of limited value for monitoring.

  18. Graphene Surface Acoustic Wave Sensor for Simultaneous Detection of Charge and Mass.

    Science.gov (United States)

    Okuda, Satoshi; Ono, Takao; Kanai, Yasushi; Ikuta, Takashi; Shimatani, Masaaki; Ogawa, Shinpei; Maehashi, Kenzo; Inoue, Koichi; Matsumoto, Kazuhiko

    2018-01-26

    We have combined a graphene field-effect transistor (GFET) and a surface acoustic wave (SAW) sensor on a LiTaO 3 substrate to create a graphene surface acoustic wave (GSAW) sensor. When a SAW propagates in graphene, an acoustoelectric current (I A ) flows between two attached electrodes. This current has unique electrical characteristics, having both positive and negative peak values with respect to the electrolyte-gate voltage (V Eg ) in solution. We found that I A is controlled by V Eg and the amplitude of the SAW. It was also confirmed that the GSAW sensor detects changes of electrical charge in solution like conventional GFET sensors. Furthermore, the detection of amino-group-modified microbeads was performed by employing a GSAW sensor in a phthalate buffer solution at pH 4.1. The hole current peak shifted to the lower left in the I A -V Eg characteristics. The left shift was caused by charge detection by the GFET and can be explained by an increase of amino groups that have positive charges at pH 4.1. In contrast, the downward shift is thought to be due to a reduction in the amplitude of the propagating SAW because of an increase in the mass loading of microbeads. This mass loading was detected by the SAW sensor. Thus, we have demonstrated that the GSAW sensor is a transducer capable of the simultaneous detection of charge and mass, which indicates that it is an attractive platform for highly sensitive and multifunctional solution sensing.

  19. Mismatch negativity to acoustical illusion of beat: how and where the change detection takes place?

    Science.gov (United States)

    Chakalov, Ivan; Paraskevopoulos, Evangelos; Wollbrink, Andreas; Pantev, Christo

    2014-10-15

    In case of binaural presentation of two tones with slightly different frequencies the structures of brainstem can no longer follow the interaural time differences (ITD) resulting in an illusionary perception of beat corresponding to frequency difference between the two prime tones. Hence, the beat-frequency does not exist in the prime tones presented to either ear. This study used binaural beats to explore the nature of acoustic deviance detection in humans by means of magnetoencephalography (MEG). Recent research suggests that the auditory change detection is a multistage process. To test this, we employed 26 Hz-binaural beats in a classical oddball paradigm. However, the prime tones (250 Hz and 276 Hz) were switched between the ears in the case of the deviant-beat. Consequently, when the deviant is presented, the cochleae and auditory nerves receive a "new afferent", although the standards and the deviants are heard identical (26 Hz-beats). This allowed us to explore the contribution of auditory periphery to change detection process, and furthermore, to evaluate its influence on beats-related auditory steady-state responses (ASSRs). LORETA-source current density estimates of the evoked fields in a typical mismatch negativity time-window (MMN) and the subsequent difference-ASSRs were determined and compared. The results revealed an MMN generated by a complex neural network including the right parietal lobe and the left middle frontal gyrus. Furthermore, difference-ASSR was generated in the paracentral gyrus. Additionally, psychophysical measures showed no perceptual difference between the standard- and deviant-beats when isolated by noise. These results suggest that the auditory periphery has an important contribution to novelty detection already at sub-cortical level. Overall, the present findings support the notion of hierarchically organized acoustic novelty detection system. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Detection of simulated pitting corrosion and noises in crude oil storage tank by acoustic emission

    International Nuclear Information System (INIS)

    Shukri Mohd; Latif, N.A.; Azhar Mohd Sinin; Mohamad Daud; Abd Nasir Ibrahim

    2008-01-01

    The damage mechanisms associated with crude oil storage tanks can be complex and varied and include pitting corrosion due to presence of species such as sulphate reducing bacteria. Acoustic Emission (AE) could be used to characterise the pitting corrosion signal in crude oil storage tanks but it is extremely difficult to simulate the pitting corrosion in the laboratory using crude oil as electrolyte because crude oil is considered as non corrosive medium. In this study, induced current have been introduced onto a surface ASTM 516 steel as an electrical source to simulate the electrical noise produced during pitting corrosion process and AE sensor have been used to detect this current. It is found that AE system could detect AE signal release during current induction this current and is expected that if the exact simulation of the current magnitude produced during pitting corrosion process is made available, AE characterisation of pitting corrosion in such tank could be made possible. (Author)

  1. Bilinear Time-frequency Analysis for Lamb Wave Signal Detected by Electromagnetic Acoustic Transducer

    Science.gov (United States)

    Sun, Wenxiu; Liu, Guoqiang; Xia, Hui; Xia, Zhengwu

    2018-03-01

    Accurate acquisition of the detection signal travel time plays a very important role in cross-hole tomography. The experimental platform of aluminum plate under the perpendicular magnetic field is established and the bilinear time-frequency analysis methods, Wigner-Ville Distribution (WVD) and the pseudo-Wigner-Ville distribution (PWVD), are applied to analyse the Lamb wave signals detected by electromagnetic acoustic transducer (EMAT). By extracting the same frequency component of the time-frequency spectrum as the excitation frequency, the travel time information can be obtained. In comparison with traditional linear time-frequency analysis method such as short-time Fourier transform (STFT), the bilinear time-frequency analysis method PWVD is more appropriate in extracting travel time and recognizing patterns of Lamb wave.

  2. Detection of bioagents using a shear horizontal surface acoustic wave biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Richard S; Hjelle, Brian; Hall, Pam R; Brown, David C; Bisoffi, Marco; Brozik, Susan M; Branch, Darren W; Edwards, Thayne L; Wheeler, David

    2014-04-29

    A biosensor combining the sensitivity of surface acoustic waves (SAW) generated at a frequency of 325 MHz with the specificity provided by antibodies and other ligands for the detection of viral agents. In a preferred embodiment, a lithium tantalate based SAW transducer with silicon dioxide waveguide sensor platform featuring three test and one reference delay lines was used to adsorb antibodies directed against Coxsackie virus B4 or the negative-stranded category A bioagent Sin Nombre virus (SNV). Rapid detection of increasing concentrations of viral particles was linear over a range of order of magnitude for both viruses, and the sensor's selectivity for its target was not compromised by the presence of confounding Herpes Simplex virus type 1 The biosensor was able to delect SNV at doses lower than the load of virus typically found in a human patient suffering from hantavirus cardiopulmonary syndrome (HCPS).

  3. Detection of bioagents using a shear horizontal surface acoustic wave biosensor

    Science.gov (United States)

    Larson, Richard S; Hjelle, Brian; Hall, Pam R; Brown, David C; Bisoffi, Marco; Brozik, Susan M; Branch, Darren W; Edwards, Thayne L; Wheeler, David

    2014-04-29

    A biosensor combining the sensitivity of surface acoustic waves (SAW) generated at a frequency of 325 MHz with the specificity provided by antibodies and other ligands for the detection of viral agents. In a preferred embodiment, a lithium tantalate based SAW transducer with silicon dioxide waveguide sensor platform featuring three test and one reference delay lines was used to adsorb antibodies directed against Coxsackie virus B4 or the negative-stranded category A bioagent Sin Nombre virus (SNV). Rapid detection of increasing concentrations of viral particles was linear over a range of order of magnitude for both viruses, and the sensor's selectivity for its target was not compromised by the presence of confounding Herpes Simplex virus type 1 The biosensor was able to delect SNV at doses lower than the load of virus typically found in a human patient suffering from hantavirus cardiopulmonary syndrome (HCPS).

  4. Bearing Fault Detection Based on Empirical Wavelet Transform and Correlated Kurtosis by Acoustic Emission.

    Science.gov (United States)

    Gao, Zheyu; Lin, Jing; Wang, Xiufeng; Xu, Xiaoqiang

    2017-05-24

    Rolling bearings are widely used in rotating equipment. Detection of bearing faults is of great importance to guarantee safe operation of mechanical systems. Acoustic emission (AE), as one of the bearing monitoring technologies, is sensitive to weak signals and performs well in detecting incipient faults. Therefore, AE is widely used in monitoring the operating status of rolling bearing. This paper utilizes Empirical Wavelet Transform (EWT) to decompose AE signals into mono-components adaptively followed by calculation of the correlated kurtosis (CK) at certain time intervals of these components. By comparing these CK values, the resonant frequency of the rolling bearing can be determined. Then the fault characteristic frequencies are found by spectrum envelope. Both simulation signal and rolling bearing AE signals are used to verify the effectiveness of the proposed method. The results show that the new method performs well in identifying bearing fault frequency under strong background noise.

  5. An Amplitude-Based Estimation Method for International Space Station (ISS) Leak Detection and Localization Using Acoustic Sensor Networks

    Science.gov (United States)

    Tian, Jialin; Madaras, Eric I.

    2009-01-01

    The development of a robust and efficient leak detection and localization system within a space station environment presents a unique challenge. A plausible approach includes the implementation of an acoustic sensor network system that can successfully detect the presence of a leak and determine the location of the leak source. Traditional acoustic detection and localization schemes rely on the phase and amplitude information collected by the sensor array system. Furthermore, the acoustic source signals are assumed to be airborne and far-field. Likewise, there are similar applications in sonar. In solids, there are specialized methods for locating events that are used in geology and in acoustic emission testing that involve sensor arrays and depend on a discernable phase front to the received signal. These methods are ineffective if applied to a sensor detection system within the space station environment. In the case of acoustic signal location, there are significant baffling and structural impediments to the sound path and the source could be in the near-field of a sensor in this particular setting.

  6. A surface acoustic wave response detection method for passive wireless torque sensor

    Science.gov (United States)

    Fan, Yanping; Kong, Ping; Qi, Hongli; Liu, Hongye; Ji, Xiaojun

    2018-01-01

    This paper presents an effective surface acoustic wave (SAW) response detection method for the passive wireless SAW torque sensor to improve the measurement accuracy. An analysis was conducted on the relationship between the response energy-entropy and the bandwidth of SAW resonator (SAWR). A self-correlation method was modified to suppress the blurred white noise and highlight the attenuation characteristic of wireless SAW response. The SAW response was detected according to both the variation and the duration of energy-entropy ascension of an acquired RF signal. Numerical simulation results showed that the SAW response can be detected even when the signal-to-noise ratio (SNR) is 6dB. The proposed SAW response detection method was evaluated with several experiments at different conditions. The SAW response can be well distinguished from the sinusoidal signal and the noise. The performance of the SAW torque measurement system incorporating the detection method was tested. The obtained repeatability error was 0.23% and the linearity was 0.9934, indicating the validity of the detection method.

  7. Development of an acoustic sensor for the future IceCube-Gen2 detector for neutrino detection and position calibration

    Directory of Open Access Journals (Sweden)

    Wickmann Stefan

    2017-01-01

    Full Text Available For the planned high-energy extension of the IceCube Neutrino Observatory in the glacial ice at the South Pole the spacing of detector modules will be increased with respect to IceCube. Because of these larger distances the quality of the geometry calibration based on pulsed light sources is expected to deteriorate. To counter this an independent acoustic geometry calibration system based on trilateration is introduced. Such an acoustic positioning system (APS has already been developed for the Enceladus Explorer Project (EnEx, initiated by the DLR Space Administration. In order to integrate such APS-sensors into the IceCube detector the power consumption needs to be minimized. In addition, the frequency response of the front end electronics is optimized for positioning as well as the acoustic detection of neutrinos. The new design of the acoustic sensor and results of test measurements with an IceCube detector module will be presented.

  8. Chemical and explosive detections using photo-acoustic effect and quantum cascade lasers

    Science.gov (United States)

    Choa, Fow-Sen

    2013-12-01

    Photoacoustic (PA) effect is a sensitive spectroscopic technique for chemical sensing. In recent years, with the development of quantum cascade lasers (QCLs), significant progress has been achieved for PA sensing applications. Using high-power, tunable mid-IR QCLs as laser sources, PA chemical sensor systems have demonstrated parts-pertrillion- level detection sensitivity. Many of these high sensitivity measurements were demonstrated locally in PA cells. Recently, we have demonstrated standoff PA detection of isopropanol vapor for more than 41 feet distance using a quantum cascade laser and a microphone with acoustic reflectors. We also further demonstrated solid phase TNT detections at a standoff distance of 8 feet. To further calibrate the detection sensitivity, we use nerve gas simulants that were generated and calibrated by a commercial vapor generator. Standoff detection of gas samples with calibrated concentration of 2.3 ppm was achieved at a detection distance of more than 2 feet. An extended detection distance up to 14 feet was observed for a higher gas concentration of 13.9 ppm. For field operations, array of microphones and microphone-reflector pairs can be utilized to achieve noise rejection and signal enhancement. We have experimentally demonstrated that the signal and noise spectra of the 4 microphone/4 reflector system with a combined SNR of 12.48 dB. For the 16-microphone and one reflector case, an SNR of 17.82 was achieved. These successful chemical sensing demonstrations will likely create new demands for widely tunable QCLs with ultralow threshold (for local fire-alarm size detection systems) and high-power (for standoff detection systems) performances.

  9. Wideband excitation in nonlinear vibro-acoustic modulation for damage detection

    Science.gov (United States)

    Klepka, A.; Adamczyk, M.; Pieczonka, L.; Staszewski, W. J.

    2016-04-01

    The paper discusses the use of wideband excitation in nonlinear vibro-acoustic modulation technique (VAM) used for damage detection. In its original form, two mono-harmonic signals (low and high frequency) are used for excitation. The low frequency excitation is typically selected based on a modal analysis test and high frequency excitation is selected arbitrarily in the ultrasonic frequency range. This paper presents a different approach with use of wideband excitation signals. The proposed approach gives the possibility to simplify the testing procedure by omitting the modal test used to determine the value of low frequency excitation. Simultaneous use of wideband excitation for high frequency solves the ambiguity related to the selection of the frequency of acoustic wave. Broadband excitation signals require, however, more elaborate signal processing methods to determine the intensity of modulation for a given bandwidth. The paper discusses the proposed approach and the related signal processing procedure. Experimental validation of the proposed technique is performed on a laminated composite plate with a barely visible impact damage that was generated in an impact test. Piezoceramic actuators are used for vibration excitation and a scanning laser vibrometer is used for noncontact data acquisition.

  10. Perceptual thresholds for detecting modifications applied to the acoustical properties of a violin.

    Science.gov (United States)

    Fritz, Claudia; Cross, Ian; Moore, Brian C J; Woodhouse, Jim

    2007-12-01

    This study is the first step in the psychoacoustic exploration of perceptual differences between the sounds of different violins. A method was used which enabled the same performance to be replayed on different "virtual violins," so that the relationships between acoustical characteristics of violins and perceived qualities could be explored. Recordings of real performances were made using a bridge-mounted force transducer, giving an accurate representation of the signal from the violin string. These were then played through filters corresponding to the admittance curves of different violins. Initially, limits of listener performance in detecting changes in acoustical characteristics were characterized. These consisted of shifts in frequency or increases in amplitude of single modes or frequency bands that have been proposed previously to be significant in the perception of violin sound quality. Thresholds were significantly lower for musically trained than for nontrained subjects but were not significantly affected by the violin used as a baseline. Thresholds for the musicians typically ranged from 3 to 6 dB for amplitude changes and 1.5%-20% for frequency changes. Interpretation of the results using excitation patterns showed that thresholds for the best subjects were quite well predicted by a multichannel model based on optimal processing.

  11. Damage detection on polymeric matrix composite materials by using acoustic emission technique

    Directory of Open Access Journals (Sweden)

    J. Cauich–Cupul

    2008-04-01

    Full Text Available In order to predict the mechanical behaviour of a composite during its service life, it is important to study the initiation and development of cracks and its effects induced by degradation. The onset of damage is related to the structural integrity of the component and its fatigue life. For this, among other reasons, non–destructive techniques have been widely used nowadays in composite materials characterization such as acoustic emission (AE. This method has demonstrated excellent results on detecting and identifying initiations sites, cracking propagation and fracture mechanisms of polymer matrix composite materials. At the same time, mechanical behaviour has been related intimately to the reinforcement architecture. The goal of this paper is to remark the importance of acoustic emission technique as a unique tool for characterising mechanical parameters in response to external stresses and degradation processes. Some results obtained from different analysis are discussed to support the significance of using AE, technique that will be increased continuously in the composite materials field due to its several alternatives for understanding the mechanical behaviour, therefore the objective of this manuscript is to involve the benefits and advantages of AE in the materials characterization.

  12. Detecting and identifying damage in sandwich polymer composite by using acoustic emission

    DEFF Research Database (Denmark)

    McGugan, M.; Sørensen, Bent F.; Østergaard, R.

    2006-01-01

    Acoustic emission is a useful monitoring tool for extracting extra information during mechanical testing of polymer composite sandwich materials. The study of fracture mechanics within test specimens extracted from wind turbine blade material ispresented. The contribution of the acoustic emission...

  13. Bat detective—Deep learning tools for bat acoustic signal detection

    Science.gov (United States)

    Barlow, Kate E.; Firman, Michael; Freeman, Robin; Harder, Briana; Kinsey, Libby; Mead, Gary R.; Newson, Stuart E.; Pandourski, Ivan; Russ, Jon; Szodoray-Paradi, Abigel; Tilova, Elena; Girolami, Mark; Jones, Kate E.

    2018-01-01

    Passive acoustic sensing has emerged as a powerful tool for quantifying anthropogenic impacts on biodiversity, especially for echolocating bat species. To better assess bat population trends there is a critical need for accurate, reliable, and open source tools that allow the detection and classification of bat calls in large collections of audio recordings. The majority of existing tools are commercial or have focused on the species classification task, neglecting the important problem of first localizing echolocation calls in audio which is particularly problematic in noisy recordings. We developed a convolutional neural network based open-source pipeline for detecting ultrasonic, full-spectrum, search-phase calls produced by echolocating bats. Our deep learning algorithms were trained on full-spectrum ultrasonic audio collected along road-transects across Europe and labelled by citizen scientists from www.batdetective.org. When compared to other existing algorithms and commercial systems, we show significantly higher detection performance of search-phase echolocation calls with our test sets. As an example application, we ran our detection pipeline on bat monitoring data collected over five years from Jersey (UK), and compared results to a widely-used commercial system. Our detection pipeline can be used for the automatic detection and monitoring of bat populations, and further facilitates their use as indicator species on a large scale. Our proposed pipeline makes only a small number of bat specific design decisions, and with appropriate training data it could be applied to detecting other species in audio. A crucial novelty of our work is showing that with careful, non-trivial, design and implementation considerations, state-of-the-art deep learning methods can be used for accurate and efficient monitoring in audio. PMID:29518076

  14. Autoregressive techniques for acoustic detection of in-sodium water leaks

    International Nuclear Information System (INIS)

    Hayashi, K.

    1997-01-01

    We have been applied a background signal whitening filter built by univariate autoregressive model to the estimation problem of the leak start time and duration. In the 1995 present benchmark stage, we evaluated the method using acoustic signals from real hydrogen or water/steam injection experiments. The results show that the signal processing technique using this filter can detect reliability the leak signals with a sufficient signal-to-noise ratio. Even if the sensor signal contains non-boiling or non-leak high-amplitude pulses, they can be classified by spectral information. Especially, the feature signal made from the time-frequency spectrum of the filtered signal is very sensitive and useful. (author). 8 refs, 14 figs, 6 tabs

  15. Influence of multi-microphone signal enhancement algorithms on auditory movement detection in acoustically complex situations

    DEFF Research Database (Denmark)

    Lundbeck, Micha; Hartog, Laura; Grimm, Giso

    2017-01-01

    The influence of hearing aid (HA) signal processing on the perception of spatially dynamic sounds has not been systematically investigated so far. Previously, we observed that interfering sounds impaired the detectability of left-right source movements and reverberation that of near-far source...... movements for elderly hearing-impaired (EHI) listeners (Lundbeck et al., 2017). Here, we explored potential ways of improving these deficits with HAs. To that end, we carried out acoustic analyses to examine the impact of two beamforming algorithms and a binaural coherence-based noise reduction scheme...... on the cues underlying movement perception. While binaural cues remained mostly unchanged, there were greater monaural spectral changes and increases in signal-to-noise ratio and direct-to-reverberant sound ratio as a result of the applied processing. Based on these findings, we conducted a listening test...

  16. Acoustic detection of a cavitation noise in the French breeder reactor Phenix

    International Nuclear Information System (INIS)

    Brunet, M.; Desprets, A.

    1981-06-01

    The French Phenix reactor is provided with an in-core multi-sensor acoustic surveillance system. But its efficiency with regard to early boiling detection is still to be proven. For lack of boiling events within the core, a cavitating dummy steel subassembly has been loaded into the reactor, as a simulation of boiling signal. Cavitation is controlled through a slow rise of the primary flow in various core conditions: isothermal situation and during a rise of power. Assuming that the signal to noise ratio is of the same order of magnitude for cavitation signals as for boiling ones, the response of several signal processing techniques is evaluated. Pulse connecting seems to be the most efficient conventional method while pattern recognition appears as a promising alternative solution

  17. Positioning and Imaging Detection of Corona Discharge in Air with Double Helix Acoustic Sensors Array

    Directory of Open Access Journals (Sweden)

    Ming Dong

    2017-12-01

    Full Text Available Corona discharge could be a serious hazard to the outdoor insulation of a high-voltage (HV system and also is an important detection issue for insulation status diagnosis. In this study, a double-helix-ultrasonic-array (DHUA sensor was developed for corona positioning, which showed a good sensitivity to the ultrasonic signal originating from corona discharge and a satisfied directional response in static beam patterns. Based on the matting-based image fusion method, the acoustic intensity matrix was fused to a visual scene in real-time. This ultrasonic visualization technology was then evaluated with a simulation test and performed in a real air insulated substation (AIS, and showed a satisfied performance in terms of sensitivity and spatial location resolution.

  18. Influence of multi-microphone signal enhancement algorithms on auditory movement detection in acoustically complex situations

    DEFF Research Database (Denmark)

    Lundbeck, Micha; Hartog, Laura; Grimm, Giso

    The influence of hearing aid (HA) signal processing on the perception of spatially dynamic sounds has not been systematically investigated so far. Previously, we observed that for elderly hearing-impaired (EHI) listeners concurrent distractor sounds impaired the detectability of left-right source...... movements, and reverberation that of near-far source movements (Lundbeck et al, Trends Hear 2017). Here, we explored potential ways of improving these deficits with HAs. To that end, we carried out detailed acoustic analyses on the stimuli used previously to examine the impact of two beamforming algorithms...... and a binaural coherence-based noise reduction scheme on the cues underlying movement perception. While the binaural cues remained mostly unchanged, the applied processing led to greater monaural spectral changes, as well as increases in signal-to-noise ratio and direct-to-reverberant sound ratio. Based...

  19. The effect of distraction on change detection in crowded acoustic scenes.

    Science.gov (United States)

    Petsas, Theofilos; Harrison, Jemma; Kashino, Makio; Furukawa, Shigeto; Chait, Maria

    2016-11-01

    In this series of behavioural experiments we investigated the effect of distraction on the maintenance of acoustic scene information in short-term memory. Stimuli are artificial acoustic 'scenes' composed of several (up to twelve) concurrent tone-pip streams ('sources'). A gap (1000 ms) is inserted partway through the 'scene'; Changes in the form of an appearance of a new source or disappearance of an existing source, occur after the gap in 50% of the trials. Listeners were instructed to monitor the unfolding 'soundscapes' for these events. Distraction was measured by presenting distractor stimuli during the gap. Experiments 1 and 2 used a dual task design where listeners were required to perform a task with varying attentional demands ('High Demand' vs. 'Low Demand') on brief auditory (Experiment 1a) or visual (Experiment 1b) signals presented during the gap. Experiments 2 and 3 required participants to ignore distractor sounds and focus on the change detection task. Our results demonstrate that the maintenance of scene information in short-term memory is influenced by the availability of attentional and/or processing resources during the gap, and that this dependence appears to be modality specific. We also show that these processes are susceptible to bottom up driven distraction even in situations when the distractors are not novel, but occur on each trial. Change detection performance is systematically linked with the, independently determined, perceptual salience of the distractor sound. The findings also demonstrate that the present task may be a useful objective means for determining relative perceptual salience. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Acoustic detections of summer and winter whales at Arctic gateways in the Atlantic and Pacific Oceans

    Science.gov (United States)

    Stafford, K.; Laidre, K. L.; Moore, S. E.

    2016-02-01

    Changes in sea ice phenology have been profound in regions north of arctic gateways, where the seasonal open-water period has increased by 1.5-3 months over the past 30 years. This has resulted in changes to the Arctic ecosystem, including increased primary productivity, changing food web structure, and opening of new habitat. In the "new normal" Arctic, ice obligate species such as ice seals and polar bears may fare poorly under reduced sea ice while sub-arctic "summer" whales (fin and humpback) are poised to inhabit new seasonal ice-free habitats in the Arctic. We examined the spatial and seasonal occurrence of summer and "winter" (bowhead) whales from September through December by deploying hydrophones in three Arctic gateways: Bering, Davis and Fram Straits. Acoustic occurrence of the three species was compared with decadal-scale changes in seasonal sea ice. In all three Straits, fin whale acoustic detections extended from summer to late autumn. Humpback whales showed the same pattern in Bering and Davis Straits, singing into November and December, respectively. Bowhead whale detections generally began after the departure of the summer whales and continued through the winter. In all three straits, summer whales occurred in seasons and regions that used to be ice-covered. This is likely due to both increased available habitat from sea ice reductions and post-whaling population recoveries. At present, in the straits examined here, there is spatial, but not temporal, overlap between summer and winter whales. In a future with further seasonal sea ice reductions, however, increased competition for resources between sub-Arctic and Arctic species may arise to the detriment of winter whales.

  1. Site specific passive acoustic detection and densities of humpback whale calls off the coast of California

    Science.gov (United States)

    Helble, Tyler Adam

    Passive acoustic monitoring of marine mammal calls is an increasingly important method for assessing population numbers, distribution, and behavior. Automated methods are needed to aid in the analyses of the recorded data. When a mammal vocalizes in the marine environment, the received signal is a filtered version of the original waveform emitted by the marine mammal. The waveform is reduced in amplitude and distorted due to propagation effects that are influenced by the bathymetry and environment. It is important to account for these effects to determine a site-specific probability of detection for marine mammal calls in a given study area. A knowledge of that probability function over a range of environmental and ocean noise conditions allows vocalization statistics from recordings of single, fixed, omnidirectional sensors to be compared across sensors and at the same sensor over time with less bias and uncertainty in the results than direct comparison of the raw statistics. This dissertation focuses on both the development of new tools needed to automatically detect humpback whale vocalizations from single-fixed omnidirectional sensors as well as the determination of the site-specific probability of detection for monitoring sites off the coast of California. Using these tools, detected humpback calls are "calibrated" for environmental properties using the site-specific probability of detection values, and presented as call densities (calls per square kilometer per time). A two-year monitoring effort using these calibrated call densities reveals important biological and ecological information on migrating humpback whales off the coast of California. Call density trends are compared between the monitoring sites and at the same monitoring site over time. Call densities also are compared to several natural and human-influenced variables including season, time of day, lunar illumination, and ocean noise. The results reveal substantial differences in call densities

  2. Detection of steam leaks into sodium in fast reactor steam generators by acoustic techniques - An overview of Indian programme

    International Nuclear Information System (INIS)

    Prabhakar, R.; Vyjayanthi, R.K.; Kale, R.D.

    1990-01-01

    Realising the potential of acoustic leak detection technique, an experimental programme was initiated a few years back at Indira Gandhi Centre for Atomic Research (IGCAR) to develop this technique. The first phase of this programme consists of experiments to measure background noise characteristics on the steam generator modules of the 40 MW (thermal) Fast Breeder Test Reactor (FBTR) at Kalpakkam and experiments to establish leak noise characteristics with the help of a leak simulation set up. By subjecting the measured data from these experiments to signal analysis techniques, a criterion for acoustic leak detection for FBTR steam generator will be evolved. Second phase of this programme will be devoted to developing an acoustic leak detection system suitable for installation in the 500 MWe Prototype Fast Breeder Reactor (PFBR). This paper discusses the first phase of the experimental programme, results obtained from measurements carried out on FBTR steam generators and results obtained from leak simulation experiments. Acoustic leak detection system being considered for PFBR is also briefly described. 4 refs, 8 figs, 1 tab

  3. Development of leak detection system of heat exchanger using acoustic emission technique

    International Nuclear Information System (INIS)

    Lee, Min Rae; Lee, Joon Hyun

    2002-01-01

    Acoustic Emission(AE) technique has been applied to not only mechanical property testing but also on-line monitoring of the entire structure or a limit zone only. Although several AE devices have already been developed for on-line monitoring, the price of these systems is very high and it is difficult for the field to apply yet. In this study, we developed a specially designed PC-based leak detection system using A/D board. In this paper, AE technique has been applied to detect leak for heat exchanger by analyzing the characteristics of signal obtained from leak. It was confirmed that the characteristics of the signal generated by the turbulence of gas in the heat exchanger is narrow band signal having between 130-250kHz. Generally, the amplitude of leak signal is increased as the leak size increasing, but showed no significant change at frequency characteristic. Leak source location can be found by determining for the point of highest signal amplitude by comparing with several fixed sensors. In this paper, AE results are compared with the PC-based leak detection system using A/D board

  4. A Urinary Bcl-2 Surface Acoustic Wave Biosensor for Early Ovarian Cancer Detection

    Directory of Open Access Journals (Sweden)

    Nathan D. Gallant

    2012-05-01

    Full Text Available In this study, the design, fabrication, surface functionalization and experimental characterization of an ultrasonic MEMS biosensor for urinary anti-apoptotic protein B-cell lymphoma 2 (Bcl-2 detection with sub ng/mL sensitivity is presented. It was previously shown that urinary Bcl-2 levels are reliably elevated during early and late stages of ovarian cancer. Our biosensor uses shear horizontal (SH surface acoustic waves (SAWs on surface functionalized ST-cut Quartz to quantify the mass loading change by protein adhesion to the delay path. SH-SAWs were generated and received by a pair of micro-fabricated interdigital transducers (IDTs separated by a judiciously designed delay path. The delay path was surface-functionalized with monoclonal antibodies, ODMS, Protein A/G and Pluronic F127 for optimal Bcl-2 capture with minimal non-specific adsorption. Bcl-2 concentrations were quantified by the resulting resonance frequency shift detected by a custom designed resonator circuit. The target sensitivity for diagnosis and identifying the stage of ovarian cancer was successfully achieved with demonstrated Bcl-2 detection capability of 500 pg/mL. It was also shown that resonance frequency shift increases linearly with increasing Bcl-2 concentration.

  5. Acoustic emission detection for mass fractions of materials based on wavelet packet technology.

    Science.gov (United States)

    Wang, Xianghong; Xiang, Jianjun; Hu, Hongwei; Xie, Wei; Li, Xiongbing

    2015-07-01

    Materials are often damaged during the process of detecting mass fractions by traditional methods. Acoustic emission (AE) technology combined with wavelet packet analysis is used to evaluate the mass fractions of microcrystalline graphite/polyvinyl alcohol (PVA) composites in this study. Attenuation characteristics of AE signals across the composites with different mass fractions are investigated. The AE signals are decomposed by wavelet packet technology to obtain the relationships between the energy and amplitude attenuation coefficients of feature wavelet packets and mass fractions as well. Furthermore, the relationship is validated by a sample. The larger proportion of microcrystalline graphite will correspond to the higher attenuation of energy and amplitude. The attenuation characteristics of feature wavelet packets with the frequency range from 125 kHz to 171.85 kHz are more suitable for the detection of mass fractions than those of the original AE signals. The error of the mass fraction of microcrystalline graphite calculated by the feature wavelet packet (1.8%) is lower than that of the original signal (3.9%). Therefore, AE detection base on wavelet packet analysis is an ideal NDT method for evaluate mass fractions of composite materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Acoustic Sensors Based on Amino-Functionalized Nanoparticles to Detect Volatile Organic Solvents

    Directory of Open Access Journals (Sweden)

    Daniel Matatagui

    2017-11-01

    Full Text Available Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were organic solvents, such as butanol, isopropanol, toluene and xylene, for a wide and low concentration range, obtaining great responses, fast response times of a few minutes (the time at which the device produced a signal change equal to 90%, good reproducibilities, and different responses for each detected solvent. The estimated limits of detection obtained have been very low for each detected compound, about 1 ppm for butanol, 12 ppm for isopropanol, 3 ppm for toluene and 0.5 ppm for xylene. Therefore, it is demonstrated that this type of acoustic wave sensor, with surface amino-functionalized nanoparticles, is a good alternative to those ones functionalized with metal nanoparticles, which result very expensive sensors to achieve worse results.

  7. Acoustic Sensors Based on Amino-Functionalized Nanoparticles to Detect Volatile Organic Solvents.

    Science.gov (United States)

    Matatagui, Daniel; Kolokoltsev, Oleg; Saniger, José Manuel; Gràcia, Isabel; Fernández, María Jesús; Fontecha, Jose Luis; Horrillo, María Del Carmen

    2017-11-14

    Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were organic solvents, such as butanol, isopropanol, toluene and xylene, for a wide and low concentration range, obtaining great responses, fast response times of a few minutes (the time at which the device produced a signal change equal to 90%), good reproducibilities, and different responses for each detected solvent. The estimated limits of detection obtained have been very low for each detected compound, about 1 ppm for butanol, 12 ppm for isopropanol, 3 ppm for toluene and 0.5 ppm for xylene. Therefore, it is demonstrated that this type of acoustic wave sensor, with surface amino-functionalized nanoparticles, is a good alternative to those ones functionalized with metal nanoparticles, which result very expensive sensors to achieve worse results.

  8. The Contact State Monitoring for Seal End Faces Based on Acoustic Emission Detection

    Directory of Open Access Journals (Sweden)

    Xiaohui Li

    2016-01-01

    Full Text Available Monitoring the contact state of seal end faces would help the early warning of the seal failure. In the acoustic emission (AE detection for mechanical seal, the main difficulty is to reduce the background noise and to classify the dispersed features. To solve these problems and achieve higher detection rates, a new approach based on genetic particle filter with autoregression (AR-GPF and hypersphere support vector machine (HSSVM is presented. First, AR model is used to build the dynamic state space (DSS of the AE signal, and GPF is used for signal filtering. Then, multiple features are extracted, and a classification model based on HSSVM is constructed for state recognition. In this approach, AR-GPF is an excellent time-domain method for noise reduction, and HSSVM has advantage on those dispersed features. Finally experimental data shows that the proposed method can effectively detect the contact state of the seal end faces and has higher accuracy rates than some other existing methods.

  9. Real-time passive acoustic detection of marine mammals from a variety of autonomous platforms

    Science.gov (United States)

    Baumgartner, M.; Van Parijs, S. M.; Hotchkin, C. F.; Gurnee, J.; Stafford, K.; Winsor, P.; Davies, K. T. A.; Taggart, C. T.

    2016-02-01

    Over the past two decades, passive acoustic monitoring has proven to be an effective means of estimating the occurrence of marine mammals. The vast majority of applications involve archival recordings from bottom-mounted instruments or towed hydrophones from moving ships; however, there is growing interest in assessing marine mammal occurrence from autonomous platforms, particularly in real time. The Woods Hole Oceanographic Institution has developed the capability to detect, classify, and remotely report in near real time the calls of marine mammals via passive acoustics from a variety of autonomous platforms, including Slocum gliders, wave gliders, and moored buoys. The mobile Slocum glider can simultaneously measure marine mammal occurrence and oceanographic conditions throughout the water column, making it well suited for studying both marine mammal distribution and habitat. Wave gliders and moored buoys provide complementary observations over much larger spatial scales and longer temporal scales, respectively. The near real-time reporting capability of these platforms enables follow-up visual observations, on-water research, or responsive management action. We have recently begun to use this technology to regularly monitor baleen whales off the coast of New England, USA and Nova Scotia, Canada, as well as baleen whales, beluga whales, and bearded seals in the Chukchi Sea off the northwest coast of Alaska, USA. Our long-range goal is to monitor occurrence over wide spatial and temporal extents as part of the regional and global ocean observatory initiatives to improve marine mammal conservation and management and to study changes in marine mammal distribution over multi-annual time scales in response to climate change.

  10. Implementing wavelet packet transform for valve failure detection using vibration and acoustic emission signals

    International Nuclear Information System (INIS)

    Sim, H Y; Ramli, R; Abdullah, M A K

    2012-01-01

    The efficiency of reciprocating compressors relies heavily on the health condition of its moving components, most importantly its valves. Previous studies showed good correlation between the dynamic response and the physical condition of the valves. These can be achieved by employing vibration technique which is capable of monitoring the response of the valve, and acoustic emission technique which is capable of detecting the valves' material deformation. However, the relationship/comparison between the two techniques is rarely investigated. In this paper, the two techniques were examined using time-frequency analysis. Wavelet packet transform (WPT) was chosen as the multi-resolution analysis technique over continuous wavelet transform (CWT), and discrete wavelet transform (DWT). This is because WPT could overcome the high computational time and high redundancy problem in CWT and could provide detailed analysis of the high frequency components compared to DWT. The features of both signals can be extracted by evaluating the normalised WPT coefficients for different time window under different valve conditions. By comparing the normalised coefficients over a certain time frame and frequency range, the feature vectors revealing the condition of valves can be constructed. One way analysis of variance was employed on these feature vectors to test the significance of data under different valve conditions. It is believed that AE signals can give a better representation of the valve condition as it can detect both the fluid motion and material deformation of valves as compared to the vibration signals.

  11. Photo-acoustic excitation and optical detection of fundamental flexural guided wave in coated bone phantoms.

    Science.gov (United States)

    Moilanen, Petro; Zhao, Zuomin; Karppinen, Pasi; Karppinen, Timo; Kilappa, Vantte; Pirhonen, Jalmari; Myllylä, Risto; Haeggström, Edward; Timonen, Jussi

    2014-03-01

    Photo-acoustic (PA) imaging was combined with skeletal quantitative ultrasound (QUS) for assessment of human long bones. This approach permitted low-frequency excitation and detection of ultrasound so as to efficiently receive the thickness-sensitive fundamental flexural guided wave (FFGW) through a coating of soft tissue. The method was tested on seven axisymmetric bone phantoms, whose 1- to 5-mm wall thickness and 16-mm diameter mimicked those of the human radius. Phantoms were made of a composite material and coated with a 2.5- to 7.5-mm layer of soft material that mimicked soft tissue. Ultrasound was excited with a pulsed Nd:YAG laser at 1064-nm wavelength and received on the same side of the coated phantom with a heterodyne interferometer. The FFGW was detected at 30-kHz frequency. Fitting the FFGW phase velocity by the FLC(1,1) tube mode provided an accurate (9.5 ± 4.0%) wall thickness estimate. Ultrasonic in vivo characterization of cortical bone thickness may thus become possible. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  12. Prospects of Frequency-Time Correlation Analysis for Detecting Pipeline Leaks by Acoustic Emission Method

    International Nuclear Information System (INIS)

    Faerman, V A; Cheremnov, A G; Avramchuk, V V; Luneva, E E

    2014-01-01

    In the current work the relevance of nondestructive test method development applied for pipeline leak detection is considered. It was shown that acoustic emission testing is currently one of the most widely spread leak detection methods. The main disadvantage of this method is that it cannot be applied in monitoring long pipeline sections, which in its turn complicates and slows down the inspection of the line pipe sections of main pipelines. The prospects of developing alternative techniques and methods based on the use of the spectral analysis of signals were considered and their possible application in leak detection on the basis of the correlation method was outlined. As an alternative, the time-frequency correlation function calculation is proposed. This function represents the correlation between the spectral components of the analyzed signals. In this work, the technique of time-frequency correlation function calculation is described. The experimental data that demonstrate obvious advantage of the time-frequency correlation function compared to the simple correlation function are presented. The application of the time-frequency correlation function is more effective in suppressing the noise components in the frequency range of the useful signal, which makes maximum of the function more pronounced. The main drawback of application of the time- frequency correlation function analysis in solving leak detection problems is a great number of calculations that may result in a further increase in pipeline time inspection. However, this drawback can be partially reduced by the development and implementation of efficient algorithms (including parallel) of computing the fast Fourier transform using computer central processing unit and graphic processing unit

  13. Detection of Adult Beetles Inside the Stored Wheat Mass Based on Their Acoustic Emissions.

    Science.gov (United States)

    Eliopoulos, P A; Potamitis, I; Kontodimas, D Ch; Givropoulou, E G

    2015-12-01

    The efficacy of bioacoustics in detecting the presence of adult beetles inside the grain mass was evaluated in the laboratory. A piezoelectric sensor and a portable acoustic emission amplifier connected with a computer were used. Adults of the most common beetle pests of stored wheat have been detected in varying population densities (0.1, 0.5, 1, and 2 adults per kilogram of wheat). The verification of the presence of the insect individuals was achieved through automated signal parameterization and classification. We tried out two different ways to detect impulses: 1) by applying a Hilbert transform on the audio recording and 2) by subtracting a noise estimation of the recording from the spectral content of the recording, thus allowing the frequency content of possible impulses to emerge. Prediction for infestation was rated falsely negative in 60-74%, 48-60%, 0-28%, and 0-4% of the cases when actual population density was 0.1, 0.5, 1, and 2 adults per kilogram, respectively, irrespective of pest species. No significant differences were recorded in positive predictions among different species in almost all cases. The system was very accurate (72-100%) in detecting 1 or 2 insects per kilogram of hard wheat grain, which is the standard threshold for classifying a grain mass "clean" or "infested." Our findings are discussed on the basis of enhancing the use of bioacoustics in stored-product IPM framework. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Detection of in-plane displacements of acoustic wave fields using extrinsic Fizeau fiber interferometric sensors

    Science.gov (United States)

    Dhawan, R.; Gunther, M. F.; Claus, R. O.

    1991-01-01

    Quantitative measurements of the in-plane particle displacement components of ultrasonic surface acoustic wave fields using extrinsic Fizeau fiber interferometric (EFFI) sensors are reported. Wave propagation in materials and the fiber sensor elements are briefly discussed. Calibrated experimental results obtained for simulated acoustic emission events on homogeneous metal test specimens are reported and compared to previous results obtained using piezoelectric transducers.

  15. Battlefield acoustics

    CERN Document Server

    Damarla, Thyagaraju

    2015-01-01

    This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

  16. Acoustic emission detection with fiber optical sensors for dry cask storage health monitoring

    Science.gov (United States)

    Lin, Bin; Bao, Jingjing; Yu, Lingyu; Giurgiutiu, Victor

    2016-04-01

    The increasing number, size, and complexity of nuclear facilities deployed worldwide are increasing the need to maintain readiness and develop innovative sensing materials to monitor important to safety structures (ITS). In the past two decades, an extensive sensor technology development has been used for structural health monitoring (SHM). Technologies for the diagnosis and prognosis of a nuclear system, such as dry cask storage system (DCSS), can improve verification of the health of the structure that can eventually reduce the likelihood of inadvertently failure of a component. Fiber optical sensors have emerged as one of the major SHM technologies developed particularly for temperature and strain measurements. This paper presents the development of optical equipment that is suitable for ultrasonic guided wave detection for active SHM in the MHz range. An experimental study of using fiber Bragg grating (FBG) as acoustic emission (AE) sensors was performed on steel blocks. FBG have the advantage of being durable, lightweight, and easily embeddable into composite structures as well as being immune to electromagnetic interference and optically multiplexed. The temperature effect on the FBG sensors was also studied. A multi-channel FBG system was developed and compared with piezoelectric based AE system. The paper ends with conclusions and suggestions for further work.

  17. The design and calibration of particular geometry piezoelectric acoustic emission transducer for leak detection and localization

    Science.gov (United States)

    Yalcinkaya, Hazim; Ozevin, Didem

    2013-09-01

    Pipeline leak detection using an acoustic emission (AE) method requires highly sensitive transducers responding to less attenuative and dispersive wave motion in order to place the discrete transducer spacing in an acceptable approach. In this paper, a new piezoelectric transducer geometry made of PZT-5A is introduced to increase the transducer sensitivity to the tangential direction. The finite element analysis of the transducer geometry is modeled in the frequency domain to identify the resonant frequency, targeting 60 kHz, and the loss factor. The numerical results are compared with the electromechanical characterization tests. The transducer response to wave motion generated in different directions is studied using a multiphysics model that couples mechanical and electrical responses of structural and piezoelectric properties. The directional dependence and the sensitivity of the transducer response are identified using the laser-induced load function. The transducer response is compared with a conventional thickness mode AE transducer under simulations and leak localization in a laboratory scale steel pipe.

  18. Particle Filter with Integrated Voice Activity Detection for Acoustic Source Tracking

    Science.gov (United States)

    Lehmann, Eric A.; Johansson, Anders M.

    2006-12-01

    In noisy and reverberant environments, the problem of acoustic source localisation and tracking (ASLT) using an array of microphones presents a number of challenging difficulties. One of the main issues when considering real-world situations involving human speakers is the temporally discontinuous nature of speech signals: the presence of silence gaps in the speech can easily misguide the tracking algorithm, even in practical environments with low to moderate noise and reverberation levels. A natural extension of currently available sound source tracking algorithms is the integration of a voice activity detection (VAD) scheme. We describe a new ASLT algorithm based on a particle filtering (PF) approach, where VAD measurements are fused within the statistical framework of the PF implementation. Tracking accuracy results for the proposed method is presented on the basis of synthetic audio samples generated with the image method, whereas performance results obtained with a real-time implementation of the algorithm, and using real audio data recorded in a reverberant room, are published elsewhere. Compared to a previously proposed PF algorithm, the experimental results demonstrate the improved robustness of the method described in this work when tracking sources emitting real-world speech signals, which typically involve significant silence gaps between utterances.

  19. Particle Filter with Integrated Voice Activity Detection for Acoustic Source Tracking

    Directory of Open Access Journals (Sweden)

    Anders M. Johansson

    2007-01-01

    Full Text Available In noisy and reverberant environments, the problem of acoustic source localisation and tracking (ASLT using an array of microphones presents a number of challenging difficulties. One of the main issues when considering real-world situations involving human speakers is the temporally discontinuous nature of speech signals: the presence of silence gaps in the speech can easily misguide the tracking algorithm, even in practical environments with low to moderate noise and reverberation levels. A natural extension of currently available sound source tracking algorithms is the integration of a voice activity detection (VAD scheme. We describe a new ASLT algorithm based on a particle filtering (PF approach, where VAD measurements are fused within the statistical framework of the PF implementation. Tracking accuracy results for the proposed method is presented on the basis of synthetic audio samples generated with the image method, whereas performance results obtained with a real-time implementation of the algorithm, and using real audio data recorded in a reverberant room, are published elsewhere. Compared to a previously proposed PF algorithm, the experimental results demonstrate the improved robustness of the method described in this work when tracking sources emitting real-world speech signals, which typically involve significant silence gaps between utterances.

  20. Seabed Detection Using Application Of Image Side Scan Sonar Instrument (Acoustic Signal

    Directory of Open Access Journals (Sweden)

    Muhammad Zainuddin Lubis

    2017-09-01

    Full Text Available The importance of knowing the method for seabed detection using side-scan sonar images with sonar instrument is a much-needed requirement right now. This kind of threat also requires frequent sonar surveys in such areas. These survey operations need specific procedures and special equipment to ensure survey correctness. In this paper describes the method of observation and retrieval of marine imagery data using an acoustic signal method, to determine a target based on the sea. Side scan sonar is an instrument consisting of single beam transducer on both sides. Side scan sonar (SSS is a sonar development that is able to show in two-dimensional images of the seabed surface with seawater conditions and target targets simultaneously. The side scan sonar data processing is performed through geometric correction to establish the actual position of the image pixel, which consists of bottom tracking, slant-range correction, layback correction and radiometric correction performed for the backscatter intensity of the digital number assigned to each pixel including the Beam Angle Correction (BAC, Automatic Gain Control (AGC, Time Varied Gain (TVG, and Empirical Gain Normalization (EGN.

  1. Robust and reliable banknote authentification and print flaw detection with opto-acoustical sensor fusion methods

    Science.gov (United States)

    Lohweg, Volker; Schaede, Johannes; Türke, Thomas

    2006-02-01

    The authenticity checking and inspection of bank notes is a high labour intensive process where traditionally every note on every sheet is inspected manually. However with the advent of more and more sophisticated security features, both visible and invisible, and the requirement of cost reduction in the printing process, it is clear that automation is required. As more and more print techniques and new security features will be established, total quality security, authenticity and bank note printing must be assured. Therefore, this factor necessitates amplification of a sensorial concept in general. We propose a concept for both authenticity checking and inspection methods for pattern recognition and classification for securities and banknotes, which is based on the concept of sensor fusion and fuzzy interpretation of data measures. In the approach different methods of authenticity analysis and print flaw detection are combined, which can be used for vending or sorting machines, as well as for printing machines. Usually only the existence or appearance of colours and their textures are checked by cameras. Our method combines the visible camera images with IR-spectral sensitive sensors, acoustical and other measurements like temperature and pressure of printing machines.

  2. Acoustic Emission Detection and Prediction of Fatigue Crack Propagation in Composite Patch Repairs Using Neural Networks

    International Nuclear Information System (INIS)

    Okafor, A. Chukwujekwu; Singh, Navdeep; Singh, Navrag

    2007-01-01

    An aircraft is subjected to severe structural and aerodynamic loads during its service life. These loads can cause damage or weakening of the structure especially for aging military and civilian aircraft, thereby affecting its load carrying capabilities. Hence composite patch repairs are increasingly used to repair damaged aircraft metallic structures to restore its structural efficiency. This paper presents the results of Acoustic Emission (AE) monitoring of crack propagation in 2024-T3 Clad aluminum panels repaired with adhesively bonded octagonal, single sided boron/epoxy composite patch under tension-tension fatigue loading. Crack propagation gages were used to monitor crack initiation. The identified AE sensor features were used to train neural networks for predicting crack length. The results show that AE events are correlated with crack propagation. AE system was able to detect crack propagation even at high noise condition of 10 Hz loading; that crack propagation signals can be differentiated from matrix cracking signals that take place due to fiber breakage in the composite patch. Three back-propagation cascade feed forward networks were trained to predict crack length based on the number of fatigue cycles, AE event number, and both the Fatigue Cycles and AE events, as inputs respectively. Network using both fatigue cycles and AE event number as inputs to predict crack length gave the best results, followed by Network with fatigue cycles as input, while network with just AE events as input had a greater error

  3. Photo-acoustic sensor for detection of oil contamination in compressed air systems.

    Science.gov (United States)

    Lassen, Mikael; Harder, David Baslev; Brusch, Anders; Nielsen, Ole Stender; Heikens, Dita; Persijn, Stefan; Petersen, Jan C

    2017-02-06

    We demonstrate an online (in-situ) sensor for continuous detection of oil contamination in compressed air systems complying with the ISO-8573 standard. The sensor is based on the photo-acoustic (PA) effect. The online and real-time PA sensor system has the potential to benefit a wide range of users that require high purity compressed air. Among these are hospitals, pharmaceutical industries, electronics manufacturers, and clean room facilities. The sensor was tested for sensitivity, repeatability, robustness to molecular cross-interference, and stability of calibration. Explicit measurements of hexane (C6H14) and decane (C10H22) vapors via excitation of molecular C-H vibrations at approx. 2950 cm-1 (3.38 μm) were conducted with a custom made interband cascade laser (ICL). For the decane measurements a (1 σ) standard deviation (STD) of 0.3 ppb was demonstrated, which corresponds to a normalized noise equivalent absorption (NNEA) coefficient for the prototype PA sensor of 2.8×10-9 W cm-1 Hz1/2.

  4. Vision-based Detection of Acoustic Timed Events: a Case Study on Clarinet Note Onsets

    Science.gov (United States)

    Bazzica, A.; van Gemert, J. C.; Liem, C. C. S.; Hanjalic, A.

    2017-05-01

    Acoustic events often have a visual counterpart. Knowledge of visual information can aid the understanding of complex auditory scenes, even when only a stereo mixdown is available in the audio domain, \\eg identifying which musicians are playing in large musical ensembles. In this paper, we consider a vision-based approach to note onset detection. As a case study we focus on challenging, real-world clarinetist videos and carry out preliminary experiments on a 3D convolutional neural network based on multiple streams and purposely avoiding temporal pooling. We release an audiovisual dataset with 4.5 hours of clarinetist videos together with cleaned annotations which include about 36,000 onsets and the coordinates for a number of salient points and regions of interest. By performing several training trials on our dataset, we learned that the problem is challenging. We found that the CNN model is highly sensitive to the optimization algorithm and hyper-parameters, and that treating the problem as binary classification may prevent the joint optimization of precision and recall. To encourage further research, we publicly share our dataset, annotations and all models and detail which issues we came across during our preliminary experiments.

  5. Detection and localisation of very high energy particles in underwater acoustic; Detection et localisation de particules de tres hautes energies en acoustique sous-marine

    Energy Technology Data Exchange (ETDEWEB)

    Juennard, N

    2007-12-15

    The theme of this thesis is included in the Antares international project whose object is to build a neutrino telescope located in a deep water environment in the Mediterranean sea. In deep water sea, a neutrino can interact with a water molecule. The collision generates a luminous flash and an acoustic wave. The goal of this work is to study this acoustic sound wave and develop a system able to detect the corresponding wave front and to estimate the initial direction of the particle. We first focus on the acoustic sound wave. Two different models are studied, and works made recently have led to a mathematical expression of both signal and wave front. Then, several detection methods are studied, from the most classical to the more recent ones. The experimental comparison in semi-real situation leads to the choice of a detection method: the Extended stochastic matched filter. Position and direction of the neutrino are now estimated with a Gauss-Newton inspired algorithm. This estimator is based on a wave front propagation model and on the time detection information given by the telescope hydro-phones. Performances of the system are then estimated. An antenna structure is then proposed and a global simulation finalizes this thesis. In this simulation, detection and estimation are based on the results found in the previous sections. Underwater sea noise is real and the results of the simulation valid our works. (author)

  6. Influence of multi-microphone signal enhancement algorithms on the acoustics and detectability of angular and radial source movements

    DEFF Research Database (Denmark)

    Lundbeck, Micha; Hartog, Laura; Grimm, Giso

    2018-01-01

    The influence of hearing aid (HA) signal processing on spatially dynamic sounds has not been systematically investigated so far. In a previous (virtual acoustics-based) study, elderly hearing-impaired (EHI) listeners showed poorer detectability for left-right (angular) and near-far (radial) source...... movements due to lateral distractor sounds and reverberation, respectively (Lundbeck, Grimm, Hohmann, Laugesen, & Neher, 2017). In the current study, potential ways of improving these deficits with HAs were explored. Using stimuli very similar to before, detailed acoustic analyses were carried out...... to examine the influence of different HA algorithms for suppressing noise and reverberation on the cues presumed to underlie source movement detectability. For an algorithm that combined unilateral directional microphones with binaural coherence-based noise reduction and for a bilateral beamformer...

  7. Acoustic detection of Oryctes rhinoceros (Coleoptera: Scarabaeidae: Dynastinae) and Nasutitermes luzonicus (Isoptera: Termitidae) in palm trees in urban Guam.

    Science.gov (United States)

    Mankin, R W; Moore, A

    2010-08-01

    Adult and larval Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae: Dynastinae) were acoustically detected in live and dead palm trees and logs in recently invaded areas of Guam, along with Nasutitermes luzonicus Oshima (Isoptera: Termitidae), and other small, sound-producing invertebrates and invertebrates. The low-frequency, long-duration sound-impulse trains produced by large, active O. rhinoceros and the higher frequency, shorter impulse trains produced by feeding N. luzonicus had distinctive spectral and temporal patterns that facilitated their identification and discrimination from background noise, as well as from roaches, earwigs, and other small sound-producing organisms present in the trees and logs. The distinctiveness of the O. rhinoceros sounds enables current usage of acoustic detection as a tactic in Guam's ongoing O. rhinoceros eradication program.

  8. Acoustic Emission Detection of Macro-Cracks on Engraving Tool Steel Inserts during the Injection Molding Cycle Using PZT Sensors

    Directory of Open Access Journals (Sweden)

    Aleš Hančič

    2013-05-01

    Full Text Available This paper presents an improved monitoring system for the failure detection of engraving tool steel inserts during the injection molding cycle. This system uses acoustic emission PZT sensors mounted through acoustic waveguides on the engraving insert. We were thus able to clearly distinguish the defect through measured AE signals. Two engraving tool steel inserts were tested during the production of standard test specimens, each under the same processing conditions. By closely comparing the captured AE signals on both engraving inserts during the filling and packing stages, we were able to detect the presence of macro-cracks on one engraving insert. Gabor wavelet analysis was used for closer examination of the captured AE signals’ peak amplitudes during the filling and packing stages. The obtained results revealed that such a system could be used successfully as an improved tool for monitoring the integrity of an injection molding process.

  9. Acoustic emission

    International Nuclear Information System (INIS)

    Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

    1990-01-01

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  10. Monitoring cetaceans in the North Pacific: analysis of retrospective SOSUS data and acoustic detection on the Northern Edge Range

    OpenAIRE

    Stafford, Kathleen

    2010-01-01

    To comply with environmental laws, the U.S. Navy has increasingly relied on acoustic detection and tracking for marine mammal monitoring/mitigation. In the North Pacific, much of what is known about large whale seasonal occurrence comes from Sound Surveillance System (SOSUS) arrays. SOSUS provides broad basin-scale assessments of large whale seasonal occurrence, but cannot provide detail at the regional level, in particular here for the Navy's Northern Edge (Training) Range in the northern...

  11. Detection of Breast Microcalcifications Under Ultrasound Using Power Doppler and Acoustic Resonance Imaging

    National Research Council Canada - National Science Library

    Weinstein, Susan

    2003-01-01

    .... Our goal with our current project was to utilize breast sonography coupled with the technique of acoustic resonance to image and evaluate the breast micorcalcifications in patients prior to biopsy...

  12. Detection of Breast Microcalcifications Under Ultrasound Using Power Doppler and Acoustic Resonance Imaging

    National Research Council Canada - National Science Library

    Weinstein, Susan

    2002-01-01

    .... Our goal with our current project was to utilize breast sonography coupled with the technique of acoustic resonance to image and evaluate the breast microcalcifications in patients prior to biopsy...

  13. Apparatus for ultrasonic visualization in sodium (VISUS) and acoustic detection in the Phenix reactor

    International Nuclear Information System (INIS)

    Lions, M.; Berger, R.; Bret, A.; Buis, H.; Barton, J.

    A description is given of two acoustic monitoring systems studied at the Fast Neutron Reactor Department at CEN/Cadarache and used in the Phenix reactor. The first is the active type, and the second, passive. The active apparatus is based on the sonar principle and permits visualizing objects inside a reactor tank, especially the heads of assemblies during handling. The passive apparatus, the acoustic detector, observes the reactor core by analyzing the acoustic noise produced in the reactor core. The electroacoustic converters are in both cases located outside, and the acoustic vibrations are transmitted by wave guides. The two pieces of apparatus can operate in a hostile environment, such as liquid metal at high temperature in the presence of high neutron and gamma fluxes

  14. The effect of distraction on change detection in crowded acoustic scenes

    OpenAIRE

    Petsas, Theofilos; Harrison, Jemma; Kashino, Makio; Furukawa, Shigeto; Chait, Maria

    2016-01-01

    In this series of behavioural experiments we investigated the effect of distraction on the maintenance of acoustic scene information in short-term memory. Stimuli are artificial acoustic ?scenes? composed of several (up to twelve) concurrent tone-pip streams (?sources?). A gap (1000?ms) is inserted partway through the ?scene?; Changes in the form of an appearance of a new source or disappearance of an existing source, occur after the gap in 50% of the trials. Listeners were instructed to moni...

  15. Detection of acoustic emission from cavitation in tissue during clinical extracorporeal lithotripsy.

    Science.gov (United States)

    Coleman, A J; Choi, M J; Saunders, J E

    1996-01-01

    A 1-MHz focused hydrophone has been used to search for acoustic emission expected to arise from cavitation occurring in tissue during clinical extracorporeal shock-wave lithotripsy (ESWL). The hydrophone is acoustically coupled to the patient's skin and the focus directed at depth in tissue under ultrasound guidance. The measured amplitude-time variation of the acoustic emission from tissue near the shock-wave focus of the Storz Modulith SL20 lithotripter has been examined in four patients. There is evidence of increased amplitude acoustic emission at 1 MHz from regions within tissue that also appear hyperechoic in simultaneously acquired ultrasound images. The acoustic emission from these regions decays from an initial peak to the noise level in about 500 microseconds following each shock-wave pulse. Within this period, a second peak, often of higher amplitude than the first, is typically observed about 100 microseconds after the shockwave. The time between the initial and second peaks is found to increase with increasing shock-wave amplitude. The results are similar to those previously observed from cavitation induced by shock-wave exposure in water and indicate that the 1-MHz acoustic emission arises from inertial cavitation in tissue during clinical ESWL.

  16. Acoustic building infiltration measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Muehleisen, Ralph T.; Raman, Ganesh

    2018-04-10

    Systems and methods of detecting and identifying a leak from a container or building. Acoustic pressure and velocity are measured. Acoustic properties are acquired from the measured values. The acoustic properties are converted to infiltration/leakage information. Nearfield Acoustic Holography (NAH) may be one method to detect the leakages from a container by locating the noise sources.

  17. A Cabled Acoustic Telemetry System for Detecting and Tracking Juvenile Salmon: Part 1. Engineering Design and Instrumentation

    Science.gov (United States)

    Weiland, Mark A.; Deng, Z. Daniel; Seim, Tom A.; LaMarche, Brian L.; Choi, Eric Y.; Fu, Tao; Carlson, Thomas J.; Thronas, Aaron I.; Eppard, M. Brad

    2011-01-01

    In 2001 the U.S. Army Corps of Engineers, Portland District (OR, USA), started developing the Juvenile Salmon Acoustic Telemetry System, a nonproprietary sensing technology, to meet the needs for monitoring the survival of juvenile salmonids through eight large hydroelectric facilities within the Federal Columbia River Power System (FCRPS). Initial development focused on coded acoustic microtransmitters and autonomous receivers that could be deployed in open reaches of the river for detection of the juvenile salmonids implanted with microtransmitters as they passed the autonomous receiver arrays. In 2006, the Pacific Northwest National Laboratory began the development of an acoustic receiver system for deployment at hydropower facilities (cabled receiver) for detecting fish tagged with microtransmitters as well as tracking them in two or three dimensions for determining route of passage and behavior as the fish passed at the facility. The additional information on route of passage, combined with survival estimates, is used by the dam operators and managers to make structural and operational changes at the hydropower facilities to improve survival of fish as they pass the facilities through the FCRPS. PMID:22163918

  18. A new framework for analysing automated acoustic species-detection data: occupancy estimation and optimization of recordings post-processing

    Science.gov (United States)

    Chambert, Thierry A.; Waddle, J. Hardin; Miller, David A.W.; Walls, Susan; Nichols, James D.

    2018-01-01

    The development and use of automated species-detection technologies, such as acoustic recorders, for monitoring wildlife are rapidly expanding. Automated classification algorithms provide a cost- and time-effective means to process information-rich data, but often at the cost of additional detection errors. Appropriate methods are necessary to analyse such data while dealing with the different types of detection errors.We developed a hierarchical modelling framework for estimating species occupancy from automated species-detection data. We explore design and optimization of data post-processing procedures to account for detection errors and generate accurate estimates. Our proposed method accounts for both imperfect detection and false positive errors and utilizes information about both occurrence and abundance of detections to improve estimation.Using simulations, we show that our method provides much more accurate estimates than models ignoring the abundance of detections. The same findings are reached when we apply the methods to two real datasets on North American frogs surveyed with acoustic recorders.When false positives occur, estimator accuracy can be improved when a subset of detections produced by the classification algorithm is post-validated by a human observer. We use simulations to investigate the relationship between accuracy and effort spent on post-validation, and found that very accurate occupancy estimates can be obtained with as little as 1% of data being validated.Automated monitoring of wildlife provides opportunity and challenges. Our methods for analysing automated species-detection data help to meet key challenges unique to these data and will prove useful for many wildlife monitoring programs.

  19. An Improved Azimuth Angle Estimation Method with a Single Acoustic Vector Sensor Based on an Active Sonar Detection System

    Science.gov (United States)

    Zhao, Anbang; Ma, Lin; Ma, Xuefei; Hui, Juan

    2017-01-01

    In this paper, an improved azimuth angle estimation method with a single acoustic vector sensor (AVS) is proposed based on matched filtering theory. The proposed method is mainly applied in an active sonar detection system. According to the conventional passive method based on complex acoustic intensity measurement, the mathematical and physical model of this proposed method is described in detail. The computer simulation and lake experiments results indicate that this method can realize the azimuth angle estimation with high precision by using only a single AVS. Compared with the conventional method, the proposed method achieves better estimation performance. Moreover, the proposed method does not require complex operations in frequency-domain and achieves computational complexity reduction. PMID:28230763

  20. An Improved Azimuth Angle Estimation Method with a Single Acoustic Vector Sensor Based on an Active Sonar Detection System.

    Science.gov (United States)

    Zhao, Anbang; Ma, Lin; Ma, Xuefei; Hui, Juan

    2017-02-20

    In this paper, an improved azimuth angle estimation method with a single acoustic vector sensor (AVS) is proposed based on matched filtering theory. The proposed method is mainly applied in an active sonar detection system. According to the conventional passive method based on complex acoustic intensity measurement, the mathematical and physical model of this proposed method is described in detail. The computer simulation and lake experiments results indicate that this method can realize the azimuth angle estimation with high precision by using only a single AVS. Compared with the conventional method, the proposed method achieves better estimation performance. Moreover, the proposed method does not require complex operations in frequencydomain and achieves computational complexity reduction.

  1. Remote listening and passive acoustic detection in a 3-D environment

    Science.gov (United States)

    Barnhill, Colin

    Teleconferencing environments are a necessity in business, education and personal communication. They allow for the communication of information to remote locations without the need for travel and the necessary time and expense required for that travel. Visual information can be communicated using cameras and monitors. The advantage of visual communication is that an image can capture multiple objects and convey them, using a monitor, to a large group of people regardless of the receiver's location. This is not the case for audio. Currently, most experimental teleconferencing systems' audio is based on stereo recording and reproduction techniques. The problem with this solution is that it is only effective for one or two receivers. To accurately capture a sound environment consisting of multiple sources and to recreate that for a group of people is an unsolved problem. This work will focus on new methods of multiple source 3-D environment sound capture and applications using these captured environments. Using spherical microphone arrays, it is now possible to capture a true 3-D environment A spherical harmonic transform on the array's surface allows us to determine the basis functions (spherical harmonics) for all spherical wave solutions (up to a fixed order). This spherical harmonic decomposition (SHD) allows us to not only look at the time and frequency characteristics of an audio signal but also the spatial characteristics of an audio signal. In this way, a spherical harmonic transform is analogous to a Fourier transform in that a Fourier transform transforms a signal into the frequency domain and a spherical harmonic transform transforms a signal into the spatial domain. The SHD also decouples the input signals from the microphone locations. Using the SHD of a soundfield, new algorithms are available for remote listening, acoustic detection, and signal enhancement The new algorithms presented in this paper show distinct advantages over previous detection and

  2. Comparison of radio-telemetric home range analysis and acoustic detection for Little Brown Bat habitat evaluation

    Science.gov (United States)

    Coleman, Laci S.; Ford, W. Mark; Dobony, Christopher A.; Britzke, Eric R.

    2014-01-01

    With dramatic declines of bat populations due to mortality caused by Pseudogymnoascus destructans (White-nose Syndrome), assessing habitat preferences of bats in the northeastern US is now critical to guide the development of regional conservation efforts. In the summer of 2012, we conducted fixed-station simultaneous telemetry to determine nocturnal spatial use and fixed-kernel home-range estimates of available habitat of a Myotis lucifugus (Le Conte) (Little Brown Bat) maternity colony in an artificial bat house. In summers of 2011 and 2012, we also deployed a 52-ha grid of 4 × 4 Anabat acoustic detectors over five 6–8-day sampling periods in various riparian and non-riparian environments in close proximity to the same bat house. The mean telemetry home range of 143 ha for bats (n = 7) completely overlapped the acoustic grid. Rankings of habitats from telemetry data for these 7 bats and 5 additional bats not included in home-range calculations but added for habitat-use measures (n = 13) revealed a higher proportional use of forested riparian habitats than other types at the landscape scale. Pair-wise comparisons of habitats indicated that bats were found significantly closer to forested riparian habitats and forests than to open water, developed areas, fields, shrublands, or wetland habitats at the landscape scale. Acoustic sampling showed that naïve occupancy was 0.8 and 0.6 and mean nightly detection probabilities were 0.23 and 0.08 at riparian and non-riparian sites, respectively. Our findings suggest that Little Brown Bats select forested riparian and forested habitats for foraging at the landscape scale but may be most easily detected acoustically at riparian sites when a simple occupancy determination for an area is required.

  3. Fiber Optic Sensor for Acoustic Detection of Partial Discharges in Oil-Paper Insulated Electrical Systems

    Directory of Open Access Journals (Sweden)

    Julio Posada-Roman

    2012-04-01

    Full Text Available A fiber optic interferometric sensor with an intrinsic transducer along a length of the fiber is presented for ultrasound measurements of the acoustic emission from partial discharges inside oil-filled power apparatus. The sensor is designed for high sensitivity measurements in a harsh electromagnetic field environment, with wide temperature changes and immersion in oil. It allows enough sensitivity for the application, for which the acoustic pressure is in the range of units of Pa at a frequency of 150 kHz. In addition, the accessibility to the sensing region is guaranteed by immune fiber-optic cables and the optical phase sensor output. The sensor design is a compact and rugged coil of fiber. In addition to a complete calibration, the in-situ results show that two types of partial discharges are measured through their acoustic emissions with the sensor immersed in oil.

  4. Acoustical Measurement and Biot Model for Coral Reef Detection and Quantification

    Directory of Open Access Journals (Sweden)

    Henry M. Manik

    2016-01-01

    Full Text Available Coral reefs are coastal resources and very useful for marine ecosystems. Nowadays, the existence of coral reefs is seriously threatened due to the activities of blast fishing, coral mining, marine sedimentation, pollution, and global climate change. To determine the existence of coral reefs, it is necessary to study them comprehensively. One method to study a coral reef by using a propagation of sound waves is proposed. In this research, the measurement of reflection coefficient, transmission coefficient, acoustic backscattering, hardness, and roughness of coral reefs has been conducted using acoustic instruments and numerical modeling using Biot theory. The results showed that the quantification of the acoustic backscatter can classify the type of coral reef.

  5. Wideband acoustic activation and detection of droplet vaporization events using a capacitive micromachined ultrasonic transducer

    Science.gov (United States)

    Novell, Anthony; Arena, Christopher B.; Oralkan, Omer; Dayton, Paul A.

    2016-01-01

    An ongoing challenge exists in understanding and optimizing the acoustic droplet vaporization (ADV) process to enhance contrast agent effectiveness for biomedical applications. Acoustic signatures from vaporization events can be identified and differentiated from microbubble or tissue signals based on their frequency content. The present study exploited the wide bandwidth of a 128-element capacitive micromachined ultrasonic transducer (CMUT) array for activation (8 MHz) and real-time imaging (1 MHz) of ADV events from droplets circulating in a tube. Compared to a commercial piezoelectric probe, the CMUT array provides a substantial increase of the contrast-to-noise ratio. PMID:27369143

  6. Acoustic Detection of Faults and Degradation in a High-Bypass Turbofan Engine during VIPR Phase III Testing

    Science.gov (United States)

    Boyle, Devin K.

    2017-01-01

    The Vehicle Integrated Propulsion Research (VIPR) Phase III project was executed at Edwards Air Force Base, California, by the National Aeronautics and Space Administration and several industry, academic, and government partners in the summer of 2015. One of the research objectives was to use external radial acoustic microphone arrays to detect changes in the noise characteristics produced by the research engine during volcanic ash ingestion and seeded fault insertion scenarios involving bleed air valves. Preliminary results indicate the successful acoustic detection of suspected degradation as a result of cumulative exposure to volcanic ash. This detection is shown through progressive changes, particularly in the high-frequency content, as a function of exposure to greater cumulative quantities of ash. Additionally, detection of the simulated failure of the 14th stage stability bleed valve and, to a lesser extent, the station 2.5 stability bleed valve, to their fully-open fail-safe positions was achieved by means of spectral comparisons between nominal (normal valve operation) and seeded fault scenarios.

  7. Accounting for false-positive acoustic detections of bats using occupancy models

    Science.gov (United States)

    Clement, Matthew J.; Rodhouse, Thomas J.; Ormsbee, Patricia C.; Szewczak, Joseph M.; Nichols, James D.

    2014-01-01

    1. Acoustic surveys have become a common survey method for bats and other vocal taxa. Previous work shows that bat echolocation may be misidentified, but common analytic methods, such as occupancy models, assume that misidentifications do not occur. Unless rare, such misidentifications could lead to incorrect inferences with significant management implications.

  8. Advanced signal processing techniques for acoustic detection of sodium/water reaction

    International Nuclear Information System (INIS)

    Yughay, V.S.; Gribok, A.V.; Volov, A.N.

    1997-01-01

    In this paper results of development of a neural network technique for processing of acoustic background noise and injection noise of various media (argon, water steam, hydrogen) at test rigs and industrial steam generator are presented. (author). 3 refs, 9 figs, 3 tabs

  9. Advanced Methods for Passive Acoustic Detection, Classification, and Localization of Marine Mammals

    Science.gov (United States)

    2015-09-30

    1962) Receptive fields, binocular interaction, and functional architecture in the cat’s visual cortex. J. Physiol. (London) 160:106-154. Jarvis... Localisation of sperm whales using bottom-mounted sensors, Applied Acoustics 67, 1074–1090 . Wiggins, S. M. and Hildebrand, J. A. (2007). High-frequency

  10. On the measurement of high-energetic neutrinos with the IceCube neutrino telescope and with acoustic detection methods

    Energy Technology Data Exchange (ETDEWEB)

    Schunck, Matthias

    2011-10-07

    In this thesis, two subjects have been addressed to enhance the detection of astrophysical neutrinos with the existing IceCube neutrino telescope as well as to explore new detection methods, namely the acoustic detection. In the first part of this thesis, the determination of the acoustic attenuation length in South-Pole ice is presented. This is part of a feasibility study to investigate the acoustic neutrino detection as a possibility to enhance the detection of the highest-energy neutrinos. For this, the acoustic properties of the ice have to be known, and the South-Pole Acoustic Test Setup (SPATS) has been built to determine these. The attenuation length is determined using in-situ measurements with SPATS and a retrievable transmitter (pinger), which was deployed in a depth between 190 and 500 m into the water-filled drilling holes. Even though, the unknown angular-dependent sensitivities of the SPATS sensor channels cannot be avoided and are considered as the dominant systematic effect for these measurements. In this thesis, the acoustic attenuation length is calculated by comparing the energy contents of the pinger pulses recorded by the various SPATS sensor channels for different distances between the pinger and the respective channel. The energy was calculated from the Fourier spectra of the pinger pulses for a frequency range between 5 and 35 kHz. The attenuation coefficient is calculated for each channel individually and the weighted mean over the distribution of all considered channels leads to an attenuation length of 264{sup +52} {sub -37} m. The dependence of the attenuation on both depth and frequency has been investigated, showing no indications for either. In the second part, a new event reconstruction method based on a Top-Down approach is presented. The method has been implemented for the IC40 detector and applied to the muon energy reconstruction. The Top-Down method is based on the direct comparison of single measured events with a large sample

  11. On-line low and high frequency acoustic leak detection and location for an automated steam generator protection system

    International Nuclear Information System (INIS)

    Gaubatz, D.C.; Gluekler, E.L.

    1990-01-01

    Two on-line acoustic leak detection systems were operated and installed on a 76 MW hockey stick steam generator in the Sodium Components Test Installation (SCTI) at the Energy Technology Engineering Center (ETEC) in Southern California. The low frequency system demonstrated the capability to detect and locate leaks, both intentional and unintentional. No false alarms were issued during the two year test program even with adjacent blasting activities, pneumatic drilling, shuttle rocket engine testing nearby, scrams of the SCTI facility, thermal/hydraulic transient testing, and pump/control valve operations. For the high frequency system the capability to detect water into sodium reactions was established utilizing frequencies as high as 300 kHz. The high frequency system appeared to be sensitive to noise generated by maintenance work and system valve operations. Subsequent development work which is incomplete as of this date showed much more promise for the high frequency system. (author). 13 figs

  12. Development of Acoustic Devices Functionalized with Cobalt Corroles or Metalloporphyrines for the Detection of Carbon Monoxide at Low Concentration

    Directory of Open Access Journals (Sweden)

    Meddy VANOTTI

    2012-03-01

    Full Text Available Progresses in synthetic chemistry methodologies has pushed to develop a large variety of artificial receptors of particular interest for chemical sensor applications. We investigate here the behavior of gas sensors based on surface acoustic wave (SAW devices. The use of Love waves that are specially sensitive to surface perturbation enables to exploit the molecular recognition processes occurring in non conductive sensing layers of cobalt corroles [5,10,15-Tris(2,6-dichlorophenylcorrolato]cobalt(III] for CO detection. We have monitored phase variations of Love-wave-based delay lines under various operation conditions and studied the detection efficiency of a differential version of our sensors. A test bench also has especially been developed to allow for the regeneration of the sensor by freeing the CO trapping sites and therefore to provide an accurate control of the operation conditions. The detection threshold reached using the proposed SAW sensor is experimentally found below one ppm.

  13. Comparison of simultaneous on-line optical and acoustic laser damage detection methods in the nanosecond pulse duration domain

    International Nuclear Information System (INIS)

    Somoskoi, T; Vass, Cs; Mero, M; Bozoki, Z; Osvay, K; Mingesz, R

    2015-01-01

    We carried out single-shot laser-induced damage threshold measurements on dielectric high reflectors guided by the corresponding ISO standard. Four simultaneous on-line detection techniques were tested and compared using 532 nm, 9 ns and 266 nm, 6 ns laser pulses. Two methods, microscope aided visual inspection and detection of scattered light off the damaged surface, were based on optical signals. The other two techniques exploited the acoustic waves accompanying a damage event in ambient air and in the substrate by a microphone and a piezoelectric sensor, respectively. A unified criterion based on the statistical analysis of the detector signals was applied to assign an objective and unambiguous damage threshold value for all of our diverse detection methods. Microscope aided visual inspection showed the lowest damage thresholds for both wavelengths. However, the sensitivity of the other three techniques proved to be only slightly lower. (paper)

  14. Comparative evaluation of acoustic techniques for detection of damages in historical wood

    Czech Academy of Sciences Publication Activity Database

    Kloiber, Michal; Reinprecht, L.; Hrivnák, Jaroslav; Tippner, J.

    2016-01-01

    Roč. 20, July-August (2016), s. 622-631 ISSN 1296-2074 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0060; GA MŠk(CZ) LO1219; GA MK(CZ) DG16P02M026 Keywords : historical wood * damages * inspection * acoustic techniques * mechanical properties Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 1.838, year: 2016 http://www.sciencedirect.com/science/article/pii/S1296207416300103

  15. Ocean Basin Impact of Ambient Noise on Marine Mammal Detectability, Distribution, and Acoustic Communication - YIP

    Science.gov (United States)

    2013-09-30

    various species of marine mammals, physical events, and anthropogenic sources such as seismic array signals, allowing for development of automated...shipping, animal vocalizations, and seismic airguns making this a “transitional” band. The 85-105 Hz band was selected as representative of the dominant...computed using a custom script written in MATLAB . Temporal (Ht) and spectral (Hf) acoustic entropies were computed and then multiplied to obtain the

  16. Laser generation and detection of longitudinal and shear acoustic waves in a diamond anvil cell

    International Nuclear Information System (INIS)

    Chigarev, Nikolay; Zinin, Pavel; Ming Lichung; Amulele, George; Bulou, Alain; Gusev, Vitalyi

    2008-01-01

    Laser ultrasonics in a point-source-point-receiver configuration is applied for the evaluation of elastic properties of nontransparent materials in a diamond anvil cell at high pressures. Measurement of both longitudinal and shear acoustic wave velocities in an iron foil at pressures up to 23 GPa does not require any information in addition to the one obtained by all-optical pump-probe technique

  17. Ocean Basin Impact of Ambient Noise on Marine Mammal Detectability, Distribution, and Acoustic Communication

    Science.gov (United States)

    2015-09-30

    of prior studies conducted at a local or regional scale. The comparison of acoustic time series from different ocean basins provides a synoptic ...current data acquisition are shown in Table 1. Data continues to be downloaded on a monthly basis to keep the database current. Sources Driving Long...variables for Bryde’s, blue, and minke whales, while the GLM was a best fit for fin whales. Significant predictors are summarized in Table 2, and

  18. Abyssopelagic fauna in the central North Pacific: comparison of acoustic detection and trawl and baited trap collections to 5800 m

    Science.gov (United States)

    Smith, K. L.; Kaufmann, R. S.; Edelman, J. L.; Baldwin, R. J.

    1992-04-01

    An integrated study using an acoustic array, opening-closing trawl and baited traps was conducted at an abyssal station in the central North Pacific (31°N, 159°W) to further characterize the near-bottom community. Two split-beam line arrays with beam patterns narrow in the vertical and omnidirectional in the horizontal were moored at 100 and 600 m above bottom (mab), sampling an insonified volume of 7855 m 3 each. In addition, a multiple opening-closing trawl (10 m 2 mouth opening) and baited traps were used to sample the fauna up to 1800 mab. Fourteen deployments of the acoustic arrays during two cruises detected 26 targets, with twice as many at 100 mab as at 600 mab (2.10 vs 0.97 targets h -1). Backscatter strengths for acoustic targets ranged from -57.2 to -26.8 dB. A total of 31 species, at least eight previously undescribed, were identified from trawl and trap collections within 1800 m of the sea floor. Of these new species, four of the decapod genus Hymenodora and one eel, Monognathus rosenblatti, were the most abundant animals collected by trawl. Other species commonly collected in baited traps included Acanthephyra quadrispinosa (Crustacea, Decapoda), Eurythenes gryllus (Crustacea, Amphipoda), and Coryphaenoides yaquinae (Osteichthyes, Macrouridae). Acoustic target abundances ranged from 0 to 1.6 animals per 10 5 m 3 per deployment, while values measured with the trawl ranged from 1.4 to 11.9 animals per 10 5 m 3. Biomass of the acoustic targets, estimated using a tentative identification based on size, and a series of regressions based on target strength and animal length and weight, ranged from 0 to 72.3 g wet weight per 10 5 m 3. Biomass estimates from the trawl samples ranged from 0.2 to 6.7 g wet weight per 10 5 m 3. The large number of new species collected during this study and the variability in sampling sparse populations using three different sampling techniques illustrate how little we know about the abyssopelagic community.

  19. Developing an early laekage detection system for thermal power plant boiler tubes by using acoustic emission technology

    International Nuclear Information System (INIS)

    Lee, Sang Bum; Roh, Seon Man

    2016-01-01

    A thermal power plant has a heat exchanger tube to collect and convert the heat generated from the high temperature and pressure steam to energy, but the tubes are arranged in a complex manner. In the event that a leakage occurs in any of these tubes, the high-pressure steam leaks out and may cause the neighboring tubes to rupture. This leakage can finally stop power generation, and hence there is a dire need to establish a suitable technology capable of detecting tube leaks at an early stage even before it occurs. As shown in this paper, by applying acoustic emission (AE) technology in existing boiler tube leak detection equipment (BTLD), we developed a system that detects these leakages early enough and generates an alarm at an early stage to necessitate action; the developed system works better that the existing system used to detect fine leakages. We verified the usability of the system in a 560 MW-class thermal power plant boiler by conducting leak tests by simulating leakages from a variety of hole sizes (⌀2, ⌀5, ⌀10 mm). Results show that while the existing fine leakage detection system does not detect fine leakages of ⌀2 mm and ⌀5 mm, the newly developed system could detect leakages early enough and generate an alarm at an early stage, and it is possible to increase the signal to more than 18 dB

  20. Acoustic events semantic detection, classification, and annotation for persistent surveillance applications

    Science.gov (United States)

    Alkilani, Amjad; Shirkhodaie, Amir

    2014-06-01

    Understanding of group activity based on analysis of spatiotemporally correlated acoustic sound events has received a minimum attention in the literature and hence is not well understood. Identification of group sub-activities such as: Human-Vehicle Interactions (HVI), Human-Object Interactions (HOI), and Human-Human Interactions (HHI) can significantly improve Situational Awareness (SA) in Persistent Surveillance Systems (PSS). In this paper, salient sound events associated with group activities are preliminary identified and applied for training a Gaussian Mixture Model (GMM) whose features are employed as feature vectors for training of algorithms for acoustic sound recognition. In this paper, discrimination of salient sounds associated with the HVI, HHI, and HOI events is achieved via a Correlation Based Template Matching (CMTM) classifier. To interlinked salient events representing an ontology-based hypothesis, a Hidden Markov Model (HMM) is employed to recognize spatiotemporally correlated events. Once such a connection is established, then, the system generates an annotation of each perceived sound event. This paper discusses the technical aspects of this approach and presents the experimental results for several outdoor group activities monitored by an array of acoustic sensors.

  1. Simulation study and guidelines to generate Laser-induced Surface Acoustic Waves for human skin feature detection

    Science.gov (United States)

    Li, Tingting; Fu, Xing; Chen, Kun; Dorantes-Gonzalez, Dante J.; Li, Yanning; Wu, Sen; Hu, Xiaotang

    2015-12-01

    Despite the seriously increasing number of people contracting skin cancer every year, limited attention has been given to the investigation of human skin tissues. To this regard, Laser-induced Surface Acoustic Wave (LSAW) technology, with its accurate, non-invasive and rapid testing characteristics, has recently shown promising results in biological and biomedical tissues. In order to improve the measurement accuracy and efficiency of detecting important features in highly opaque and soft surfaces such as human skin, this paper identifies the most important parameters of a pulse laser source, as well as provides practical guidelines to recommended proper ranges to generate Surface Acoustic Waves (SAWs) for characterization purposes. Considering that melanoma is a serious type of skin cancer, we conducted a finite element simulation-based research on the generation and propagation of surface waves in human skin containing a melanoma-like feature, determine best pulse laser parameter ranges of variation, simulation mesh size and time step, working bandwidth, and minimal size of detectable melanoma.

  2. Detection of Metallic and Electronic Radar Targets by Acoustic Modulation of Electromagnetic Waves

    Science.gov (United States)

    2017-07-01

    is 2 ft. This short distance is within the near field of the antenna. The DUT is attached to a 3-ft-long fiberglass rod using a pair of rare -earth...2003 July;51(7):1499–1507. 14. Scott WR, Schroeder C, Martin JS. An acousto-electromagnetic sensor for locating land mines. In: Proc SPIE 3392...1998 Apr. p. 176–186. 15. Scott WR, Schroeder C, and Martin JS. A hybrid acoustic/electromagnetic technique for locating land mines. In Proc Int

  3. Acoustic emission analysis for the detection of appropriate cutting operations in honing processes

    Science.gov (United States)

    Buj-Corral, Irene; Álvarez-Flórez, Jesús; Domínguez-Fernández, Alejandro

    2018-01-01

    In the present paper, acoustic emission was studied in honing experiments obtained with different abrasive densities, 15, 30, 45 and 60. In addition, 2D and 3D roughness, material removal rate and tool wear were determined. In order to treat the sound signal emitted during the machining process, two methods of analysis were compared: Fast Fourier Transform (FFT) and Hilbert Huang Transform (HHT). When density 15 is used, the number of cutting grains is insufficient to provide correct cutting, while clogging appears with densities 45 and 60. The results were confirmed by means of treatment of the sound signal. In addition, a new parameter S was defined as the relationship between energy in low and high frequencies contained within the emitted sound. The selected density of 30 corresponds to S values between 0.1 and 1. Correct cutting operations in honing processes are dependent on the density of the abrasive employed. The density value to be used can be selected by means of measurement and analysis of acoustic emissions during the honing operation. Thus, honing processes can be monitored without needing to stop the process.

  4. Predicting the characteristics of thunder on Titan: A framework to assess the detectability of lightning by acoustic sensing

    Science.gov (United States)

    Petculescu, Andi; Kruse, Roland

    2014-10-01

    The search for lightning is an important item on the agenda for the future exploration of Titan. Thunder, as a direct lightning signature, can be used, together with electromagnetic signals, to corroborate and quantify lightning. Using Cassini-Huygens data and model predictions, the main characteristics of thunder produced by a potential 20 km cloud-to-ground tortuous discharge are obtained and discussed. The acoustic power released right after the discharge decreases with increasing altitude, owing to the ambient pressure and temperature gradients. Ray tracing is used to propagate sound waves to the far field. Simulated thunder waveforms are characterized by fairly long codas—on the order of tens of seconds—arising from the small acoustic absorption (˜10-4dB/km). In the low-loss environment, the principal thunder arrival will likely have a large signal-to-noise ratio ensuring a high detection selectivity. The spectral content depends on the amount of energy released during the discharge. For an energy density of 5 kJ/m, the dominant contribution lies between 50 and 80 Hz; for 500 kJ/m, it shifts to lower frequencies between 10 and 30 Hz.

  5. Proceedings of a seminar on the potential for LMFBR boiling detection by acoustic/neutronic monitoring, Argonne, Illinois, April 8--9, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Carey, W.M.; Albrecht, R.W.

    1976-06-01

    A seminar involving ten technical presentations by principal investigators was held to assess the current scope of ERDA-sponsored programs to determine the feasibility of sodium-boiling detection in LMFBRs and to establish areas in need of additional research and development. The consensus was that (1) feasibility of boiling detection by acoustic, neutronic, and acoustic/neutronic monitors has been demonstrated in U.S. and European programs; (2) additional research and development is needed in areas of reactor noise, cavitation, and the effects of noncondensible gases on sound source levels and transmission; (3) the role of acoustic/neutronic monitors from the standpoint of reactor surveillance rather than reactor safety is a viable approach to be adapted; and, in particular (4) a need exists for an operational LMFBR demonstration system. Each paper has been separately abstracted and indexed. (DG)

  6. Mean grain size detection of DP590 steel plate using a corrected method with electromagnetic acoustic resonance.

    Science.gov (United States)

    Wang, Bin; Wang, Xiaokai; Hua, Lin; Li, Juanjuan; Xiang, Qing

    2017-04-01

    Electromagnetic acoustic resonance (EMAR) is a considerable method to determine the mean grain size of the metal material with a high precision. The basic ultrasonic attenuation theory used for the mean grain size detection of EMAR is come from the single phase theory. In this paper, the EMAR testing was carried out based on the ultrasonic attenuation theory. The detection results show that the double peaks phenomenon occurs in the EMAR testing of DP590 steel plate. The dual phase structure of DP590 steel is the inducement of the double peaks phenomenon in the EMAR testing. In reaction to the phenomenon, a corrected method with EMAR was put forward to detect the mean grain size of dual phase steel. Compared with the traditional attenuation evaluation method and the uncorrected method with EMAR, the corrected method with EMAR shows great effectiveness and superiority for the mean grain size detection of DP590 steel plate. Copyright © 2016. Published by Elsevier B.V.

  7. A novel approach to detect respiratory phases from pulmonary acoustic signals using normalised power spectral density and fuzzy inference system.

    Science.gov (United States)

    Palaniappan, Rajkumar; Sundaraj, Kenneth; Sundaraj, Sebastian; Huliraj, N; Revadi, S S

    2016-07-01

    Monitoring respiration is important in several medical applications. One such application is respiratory rate monitoring in patients with sleep apnoea. The respiratory rate in patients with sleep apnoea disorder is irregular compared with the controls. Respiratory phase detection is required for a proper monitoring of respiration in patients with sleep apnoea. To develop a model to detect the respiratory phases present in the pulmonary acoustic signals and to evaluate the performance of the model in detecting the respiratory phases. Normalised averaged power spectral density for each frame and change in normalised averaged power spectral density between the adjacent frames were fuzzified and fuzzy rules were formulated. The fuzzy inference system (FIS) was developed with both Mamdani and Sugeno methods. To evaluate the performance of both Mamdani and Sugeno methods, correlation coefficient and root mean square error (RMSE) were calculated. In the correlation coefficient analysis in evaluating the fuzzy model using Mamdani and Sugeno method, the strength of the correlation was found to be r = 0.9892 and r = 0.9964, respectively. The RMSE for Mamdani and Sugeno methods are RMSE = 0.0853 and RMSE = 0.0817, respectively. The correlation coefficient and the RMSE of the proposed fuzzy models in detecting the respiratory phases reveals that Sugeno method performs better compared with the Mamdani method. © 2014 John Wiley & Sons Ltd.

  8. Determination of the entropy change using the acoustic detection technique in the investigation of the magnetocaloric effect

    Energy Technology Data Exchange (ETDEWEB)

    Soffner, M E; Mansanares, A M; Gandra, F C G; Coelho, A A [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), CP 6165, 13083-970, Campinas, SP (Brazil); Gama, S [Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo (UNIFESP), 09972-270, Diadema, SP (Brazil); Carvalho, A Magnus G; Pires, M J M [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), 25250-020, Duque de Caxias, RJ (Brazil); Guimaraes, A O; Silva, E C da, E-mail: manoel@ifi.unicamp.b [Laboratorio de Ciencias Fisicas, Universidade Estadual do Norte Fluminense Darcy Ribeiro, 28013-602, Campos dos Goytacazes, RJ (Brazil)

    2010-11-10

    In this paper we demonstrate the use of the acoustic detection as an alternative way to determine the entropy variation, {Delta}S{sub T}, a parameter normally used to characterize the magnetocaloric effect. The measurements were performed for a Gd sample in the 252-316 K temperature range for magnetic fields from zero up to 50 kOe. The reversible adiabatic curves were built in a T versus H diagram, and specific heat data obtained at zero-magnetic field were employed to assign the entropy values of each curve. Subsequently, the entropy was plotted as a function of temperature for fixed magnetic fields, and therefore the isothermal entropy variation, {Delta}S{sub T}, was found as a function of the temperature for several magnetic field steps.

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

    Science.gov (United States)

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

    2009-07-01

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

  10. Leak Detection in Water-Filled Small-Diameter Polyethylene Pipes by Means of Acoustic Emission Measurements

    Directory of Open Access Journals (Sweden)

    Alberto Martini

    2016-12-01

    Full Text Available The implementation of effective strategies to manage leaks represents an essential goal for all utilities involved with drinking water supply in order to reduce water losses affecting urban distribution networks. This study concerns the early detection of leaks occurring in small-diameter customers’ connections to water supply networks. An experimental campaign was carried out in a test bed to investigate the sensitivity of Acoustic Emission (AE monitoring to water leaks. Damages were artificially induced on a polyethylene pipe (length 28 m, outer diameter 32 mm at different distances from an AE transducer. Measurements were performed in both unburied and buried pipe conditions. The analysis permitted the identification of a clear correlation between three monitored parameters (namely total Hits, Cumulative Counts and Cumulative Amplitude and the characteristics of the examined leaks.

  11. Determination of the entropy change using the acoustic detection technique in the investigation of the magnetocaloric effect

    International Nuclear Information System (INIS)

    Soffner, M E; Mansanares, A M; Gandra, F C G; Coelho, A A; Gama, S; Carvalho, A Magnus G; Pires, M J M; Guimaraes, A O; Silva, E C da

    2010-01-01

    In this paper we demonstrate the use of the acoustic detection as an alternative way to determine the entropy variation, ΔS T , a parameter normally used to characterize the magnetocaloric effect. The measurements were performed for a Gd sample in the 252-316 K temperature range for magnetic fields from zero up to 50 kOe. The reversible adiabatic curves were built in a T versus H diagram, and specific heat data obtained at zero-magnetic field were employed to assign the entropy values of each curve. Subsequently, the entropy was plotted as a function of temperature for fixed magnetic fields, and therefore the isothermal entropy variation, ΔS T , was found as a function of the temperature for several magnetic field steps.

  12. Developments in Analytical Chemistry: Acoustically Levitated Drop Reactors for Enzyme Reaction Kinetics and Single-Walled Carbon Nanotube-Based Sensors for Detection of Toxic Organic Phosphonates

    Science.gov (United States)

    Field, Christopher Ryan

    2009-01-01

    Developments in analytical chemistry were made using acoustically levitated small volumes of liquid to study enzyme reaction kinetics and by detecting volatile organic compounds in the gas phase using single-walled carbon nanotubes. Experience gained in engineering, electronics, automation, and software development from the design and…

  13. Simulation-based design of a steerable acoustic warning device to increase (H)EV detectability while reducing urban noise pollution

    NARCIS (Netherlands)

    Van Genechten, B.; Berkhoff, Arthur P.

    2014-01-01

    This paper describes the simulation-based design methodology used in the eVADER project for the development of targeted acoustic warning devices for increased detectability of Hybrid and Electric Vehicles (HEVs) while, at the same time, reducing urban noise pollution compared to conventional

  14. Detection of multiple AE signal by triaxial hodogram analysis; Sanjiku hodogram ho ni yoru taju acoustic emission no kenshutsu

    Energy Technology Data Exchange (ETDEWEB)

    Nagano, K.; Yamashita, T. [Muroran Institute of Technology, Hokkaido (Japan)

    1997-05-27

    In order to evaluate dynamic behavior of underground cracks, analysis and detection were attempted on multiple acoustic emission (AE) events. The multiple AE is a phenomenon in which multiple AE signals generated by underground cracks developed in an extremely short time interval are superimposed, and observed as one AE event. The multiple AE signal consists of two AE signals, whereas the second P-wave is supposed to have been inputted before the first S-wave is inputted. The first P-wave is inputted first, where linear three-dimensional particle movements are observed, but the movements are made random due to scattering and sensor characteristics. When the second P-wave is inputted, the linear particle movements are observed again, but are superimposed with the existing input signals and become multiple AE, which creates poor S/N ratio. The multiple AE detection determines it a multiple AE event when three conditions are met, i. e. a condition of equivalent time interval of a maximum value in a scalogram analysis, a condition of P-wave vibrating direction, and a condition of the linear particle movement. Seventy AE signals observed in the Kakkonda geothermal field were analyzed and AE signals that satisfy the multiple AE were detected. However, further development is required on an analysis method with high resolution for the time. 4 refs., 4 figs.

  15. Acoustic tag detections of green sturgeon in the Columbia River and Coos Bay estuaries, Washington and Oregon, 2010–11

    Science.gov (United States)

    Hansel, Hal C.; Romine, Jason G.; Perry, Russell W.

    2017-11-08

    The Columbia River, in Washington and Oregon, and Coos Bay, in Oregon, are economically important shipping channels that are inhabited by several fishes protected under the Endangered Species Act (ESA). Maintenance of shipping channels involves dredge operations to maintain sufficient in-channel depths to allow large ships to navigate the waterways safely. Fishes entrained by dredge equipment often die or experience delayed mortality. Other potential negative effects of dredging include increased turbidity, reductions in prey resources, and the release of harmful contaminants from the dredged sediments. One species of concern is the ESA-listed green sturgeon (Acipenser medirostris; Southern Distinct Population Segment). In this study, we used acoustic telemetry to identify habitat use, arrival and departure timing, and the extent of upstream migration of green sturgeon in the Columbia River and Coos Bay to help inform dredge operations to minimize potential take of green sturgeon. Autonomous acoustic receivers were deployed in Coos Bay from the mouth to river kilometer (rkm) 21.6 from October 2009 through October 2010. In the Columbia River Estuary, receivers were deployed between the mouth and rkm 37.8 from April to November in 2010 and 2011. A total of 29 subadult and adult green sturgeon were tagged with temperature and pressure sensor tags and released during the study, primarily in Willapa Bay and Grays Harbor, Washington, and the Klamath River, Oregon. Green sturgeon detected during the study but released by other researchers also were included in the study.The number of tagged green sturgeon detected in the two estuaries differed markedly. In Coos Bay, only one green sturgeon was detected for about 2 hours near the estuary mouth. In the Columbia River Estuary, 9 green sturgeon were detected in 2010 and 10 fish were detected in 2011. Green sturgeon entered the Columbia River from May through October during both years, with the greatest numbers of fish being

  16. Workshop on the Detection, Classification, Localization and Density Estimation of Marine Mammals Using Passive Acoustics - 2015

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Workshop on the Detection, Classification, Localization...OBJECTIVES The Seventh International Workshop on Detection, Classification, Localization, and Density Estimation (DCLDE) of Marine Mammals Using... workshop was to facilitate its organization and to increase the level of particapation by students and others working in the field. APPROACH The

  17. Detecting crack profile in concrete using digital image correlation and acoustic emission

    Directory of Open Access Journals (Sweden)

    Loukili A.

    2010-06-01

    Full Text Available Failure process in concrete structures is usually accompanied by cracking of concrete. Understanding the cracking pattern is very important while studying the failure governing criteria of concrete. The cracking phenomenon in concrete structures is usually complex and involves many microscopic mechanisms caused by material heterogeneity. Since last many years, fracture or damage analysis by experimental examinations of the cement based composites has shown importance to evaluate the cracking and damage behavior of those heterogeneous materials with damage accumulation due to microcracks development ahead of the propagating crack tip; and energy dissipation resulted during the evolution of damage in the structure. The techniques used in those experiments may be the holographic interferometry, the dye penetration, the scanning electron microscopy, the acoustic emission etc. Those methods offer either the images of the material surface to observe micro-features of the concrete with qualitative analysis, or the black-white fringe patterns of the deformation on the specimen surface, from which it is difficult to observe profiles of the damaged materials.

  18. Detection of internal cracks in rubber composite structures using an impact acoustic modality

    Science.gov (United States)

    Shen, Q.; Kurfess, T. R.; Omar, M.; Gramling, F.

    2014-01-01

    The objective of this study is to investigate the use of impact acoustic signals to non-intrusively inspect rubber composite structures for the presence of internal cracks, such as those found in an automobile tyre. Theoretical contact dynamic models for both integral and defective rubber structures are developed based on Hertz's impact model, further modified for rubber composite materials. The model generates the prediction of major impact dynamic quantities, namely the maximum impact force, impact duration and contact deformation; such parameters are also theoretically proven to be correlated with the presence of internal cracks. The tyre structures are simplified into cubic rubber blocks, to mitigate complexity for analytical modelling. Both impact force and impact sound signals are measured experimentally, and extraction of useful features from both signals for defect identification is achieved. The impact force produces two direct measurements of theoretical impact dynamic quantities. A good correlation between these experimental discriminators and the theoretical dynamic quantities provide validation for the contact dynamics models. Defect discriminators extracted from the impact sound are dependent on both time- and frequency-domain analyses. All the discriminators are closely connected with the theoretical dynamic quantities and experimentally verified as good indicators of internal cracks in rubber composite structures.

  19. Acoustic signal processing for the detection of sodium boiling or sodium-water reaction in LMFRs. Final report of a co-ordinated research programme 1990-1995

    International Nuclear Information System (INIS)

    1997-05-01

    This report is a summary of the work performed under a co-ordinated research programme entitled Acoustic Signal Processing for the Detection of Sodium Boiling or Sodium-Water Reaction in Liquid Metal Cooled Fast Reactors. The programme was organized by the IAEA and carried out from 1990 to 1995. It was the continuation of an earlier research co-ordination programme entitled Signal Processing Techniques for Sodium Boiling Noise Detection, which was carried out from 1984 to 1989. Refs, figs, tabs

  20. Design of an Acoustic Target Intrusion Detection System Based on Small-Aperture Microphone Array

    Science.gov (United States)

    Zu, Xingshui; Guo, Feng; Huang, Jingchang; Zhao, Qin; Liu, Huawei; Li, Baoqing; Yuan, Xiaobing

    2017-01-01

    Automated surveillance of remote locations in a wireless sensor network is dominated by the detection algorithm because actual intrusions in such locations are a rare event. Therefore, a detection method with low power consumption is crucial for persistent surveillance to ensure longevity of the sensor networks. A simple and effective two-stage algorithm composed of energy detector (ED) and delay detector (DD) with all its operations in time-domain using small-aperture microphone array (SAMA) is proposed. The algorithm analyzes the quite different velocities between wind noise and sound waves to improve the detection capability of ED in the surveillance area. Experiments in four different fields with three types of vehicles show that the algorithm is robust to wind noise and the probability of detection and false alarm are 96.67% and 2.857%, respectively. PMID:28273838

  1. Design of an Acoustic Target Intrusion Detection System Based on Small-Aperture Microphone Array.

    Science.gov (United States)

    Zu, Xingshui; Guo, Feng; Huang, Jingchang; Zhao, Qin; Liu, Huawei; Li, Baoqing; Yuan, Xiaobing

    2017-03-04

    Automated surveillance of remote locations in a wireless sensor network is dominated by the detection algorithm because actual intrusions in such locations are a rare event. Therefore, a detection method with low power consumption is crucial for persistent surveillance to ensure longevity of the sensor networks. A simple and effective two-stage algorithm composed of energy detector (ED) and delay detector (DD) with all its operations in time-domain using small-aperture microphone array (SAMA) is proposed. The algorithm analyzes the quite different velocities between wind noise and sound waves to improve the detection capability of ED in the surveillance area. Experiments in four different fields with three types of vehicles show that the algorithm is robust to wind noise and the probability of detection and false alarm are 96.67% and 2.857%, respectively.

  2. Preventive detection of incipient failure and improvement of availability of French PWR using acoustic emission

    International Nuclear Information System (INIS)

    Audenard, B.; Marini, J.

    1982-08-01

    Laboratory tests, on site experience gained on PWR during start up test as well as during nominal functioning have given FRAMATOME very great confidence in A.E. techniques for preventive detection of incidents. Loose part and leakage monitoring are already being used on an industrial basis. Crack growth detection and monitoring are still in the investigation phase and various. Research and Development programs are presently being carried out

  3. Innovative Acoustic Sensor Technologies for Leak Detection in Challenging Pipe Types

    Science.gov (United States)

    2016-12-30

    cover the entire water distribution network (or subsets) and provides for real-time leak detection on a daily basis. The second approach was use of...and to limit the drawdown of local water supplies. Implementation of improved leak detection technologies and the timely repair of water mains will...Performance Objectives for Field Leak Testing ( Water Distribution System) ........ 23 4.0 FACILITY/SITE DESCRIPTION

  4. Criteria for assessing the quality of signal processing techniques for acoustic leak detection

    International Nuclear Information System (INIS)

    Prabhakar, R.; Singh, O.P.

    1990-01-01

    In this paper the criteria used in the first IAEA coordinated research programme to assess the quality of signal processing techniques for sodium boiling noise detection are highlighted. Signal processing techniques, using new features sensitive to boiling and a new approach for achieving higher reliability of detection, which were developed at Indira Gandhi Centre for Atomic Research are also presented. 10 refs, 3 figs, 2 tabs

  5. Identification of acoustic wave propagation in a duct line and its application to detection of impact source location based on signal processing

    International Nuclear Information System (INIS)

    Shin, Yong Woo; Kim, Min Soo; Lee, Sang Kwon

    2010-01-01

    For the detection of the impact location in a pipeline system, the correlation method has been the conventional method. For the application of the correlation method, the diameter of a duct should be small so that the acoustic wave inside the duct can propagate with nondispersive characteristics, in the form of, for example, a plane wave. This correlation method calculates the cross-correlation between acoustic waves measured at two acceleration sensors attached to a buried duct. It also gives information about the arrival time delay of an acoustic wave between two sensors. These arrival time delays are used for the estimation of the impact location. However, when the diameter of the duct is large, the acoustic waves inside the duct propagate with dispersive characteristics owing to the reflection of the acoustic wave off of the wall of the duct. This dispersive characteristic is related to the acoustic modes inside a duct. Therefore, the correlation method does not work correctly for the detection of the impact location. This paper proposes new methods of accurately measuring the arrival time delay between two sensors attached to duct line system. This method is based on the time-frequency analyses of the short time Fourier transform (STFT) and continuous wavelet transform (CWT). These methods can discriminate direct waves (non-dispersive waves) and reflective waves (dispersive waves) from the measured wave signals through the time-frequency analysis. The direct wave or the reflective wave is used to estimate the arrival time delay. This delay is used for the identification of the impact location. This systematic method can predict the impact location due to the impact forces of construction equipment with more accuracy than the correlation method

  6. Active acoustic leak detection for LMFBR steam generator. Pt. 5. Experiment for detection of bubbles using the SG full sector model

    International Nuclear Information System (INIS)

    Kumagai, Hiromichi

    1997-01-01

    In order to prevent the expansion of tube damages and to maintain structural safety in steam generators (SG) of fast breeder reactors (FBR), it is necessary to detect precisely and immediately the leakage of water from tubes of heat exchangers. Therefore, an active acoustic method, which detects the sound attenuation due to bubbles generated in the sodium-water reactions, it being developed. In this paper, the attenuation characteristics of sound attenuated by bubbles and influence of background noise are investigated experimentally by using an SG full sector model (diameter ratio about 1/1, height ratio about 1/7) simulating the actual SG. As an experimental result, the received sound attenuation for ten seconds was more than 10 dB from air bubble injection when injected bubble of 10 l/s (equivalence water leak rate about 10 g/s). The attenuation of sound are least affected by bubble injection position of heat exchanger tube bunch department. And the time was about 25 seconds till the sound attenuation became 10 dB in case of quantity of air bubble 1 l/s (equivalent water leak rate about 1 g/s). It is clarified that the background noise hardly influenced water leak detection performance as a result of having examined influence of background noise. (author)

  7. Architectural acoustics

    National Research Council Canada - National Science Library

    Long, Marshall

    2014-01-01

    .... Beginning with a brief history, it reviews the fundamentals of acoustics, human perception and reaction to sound, acoustic noise measurements, noise metrics, and environmental noise characterization...

  8. Passive Acoustic Detection of Wind Turbine In-Flow Conditions for Active Control and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Nathan E.

    2012-03-12

    Wind is a significant source of energy; however, the human capability to produce electrical energy still has many hurdles to overcome. One of these is the unpredictability of the winds in the atmospheric boundary layer (ABL). The ABL is highly turbulent in both stable and unstable conditions (based on the vertical temperature profile) and the resulting fluctuations can have a dramatic impact on wind turbine operation. Any method by which these fluctuations could be observed, estimated, or predicted could provide a benefit to the wind energy industry as a whole. Based on the fundamental coupling of velocity fluctuations to pressure fluctuations in the nearly incompressible flow in the ABL, This work hypothesizes that a ground-based array of infrasonic pressure transducers could be employed to estimate the vertical wind profile over a height relevant for wind turbines. To analyze this hypothesis, experiments and field deployments were conducted. Wind tunnel experiments were performed for a thick turbulent boundary layer over a neutral or heated surface. Surface pressure and velocity probe measurements were acquired simultaneously. Two field deployments yielded surface pressure data from a 49 element array. The second deployment at the Reese Technology Center in Lubbock, TX, also included data from a smaller aperture, 96-element array and a 200-meter tall meteorological tower. Analysis of the data successfully demonstrated the ability to estimate the vertical velocity profile using coherence data from the pressure array. Also, dynamical systems analysis methods were successful in identifying and tracking a gust type event. In addition to the passive acoustic profiling method, this program also investigated a rapid response Doppler SODAR system, the optimization of wind turbine blades for enhanced power with reduced aeroacoustic noise production, and the implementation of a wireless health monitoring system for the wind turbine blades. Each of these other objectives

  9. Non-contact detection of pulsed acoustic displacements for the evaluation of sub-surface defects

    NARCIS (Netherlands)

    Bruinsma, A.J.A.

    1987-01-01

    The development of optical methods for detection of ultrasound is important for the technology of non-contact Non-Destructive Evaluation of materials. Several optical methods are limited in their application by their sensitivity for ambient vibrations or their complexity. In this paper a Fiber Time

  10. The simulation of acoustic propagation within SG water leak detection system

    International Nuclear Information System (INIS)

    Suzuki, Takehiko; Shioyama, Tsutomu

    1996-01-01

    It is important to detect the leak sound signal in a steam generator tube. For this purpose, it is necessary to develop the detection system capable of detecting the leak sound signal buried in external noises. This leak sound signal is measured the acceleration on the wall of the steam generator. The authors used a simulation technique to investigate how the sound generated in a steam generator propagates out of the generator. The results obtained using the simulation technique clarify that the observed signal had many resonation frequency courses due to scattering from complex structures. Therefore, the information of the original signal is lost. However, if the acceleration value many points on the outer wall is detected, and cross-correlation are obtained from each coupled measurement point, it is possible to separate the direct wave from a source point from the scattering waves in a measurement signal. Using the cross-correlation value, the source point of the leak sound signal in a steam generator tube is determined by the synthetic aperture focusing technique

  11. Acoustic lenses

    International Nuclear Information System (INIS)

    Kittmer, C.A.

    1983-03-01

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  12. New methods for leaks detection and localisation using acoustic emission; Nouvelles methodes de detection et de localisation de fuites par emission acoustique

    Energy Technology Data Exchange (ETDEWEB)

    Boulanger, P.

    1993-12-08

    Real time monitoring of Pressurized Water nuclear Reactor secondary coolant system tends to integrate digital processing machines. In this context, the method of acoustic emission seems to exhibit good performances. Its principle is based on passive listening of noises emitted by local micro-displacements inside a material under stress which propagate as elastic waves. The lack of a priori knowledge on leak signals leads us to go deeper into understanding flow induced noise generation. Our studies are conducted using a simple leak model depending on the geometry and the king of flow inside the slit. Detection and localization problems are formulated according to the maximum likelihood principle. For detection, the methods using a indicator of similarity (correlation, higher order correlation) seems to give better results than classical ones (rms value, envelope, filter banks). For leaks location, a large panel of classical (generalized inter-correlation) and innovative (convolution, adaptative, higher order statistics) methods of time delay estimation are presented. The last part deals with the applications of higher order statistics. The analysis of higher order estimators of a non linear non Gaussian stochastic process family, the improvement of non linear prediction performances and the optimal-order choice problem are addressed in simple analytic cases. At last, possible applications to leak signals analysis are pointed out. (authors).264 refs., 7 annexes.

  13. Acoustic Longitudinal Field NIF Optic Feature Detection Map Using Time-Reversal & MUSIC

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K

    2006-02-09

    We developed an ultrasonic longitudinal field time-reversal and MUltiple SIgnal Classification (MUSIC) based detection algorithm for identifying and mapping flaws in fused silica NIF optics. The algorithm requires a fully multistatic data set, that is one with multiple, independently operated, spatially diverse transducers, each transmitter of which, in succession, launches a pulse into the optic and the scattered signal measured and recorded at every receiver. We have successfully localized engineered ''defects'' larger than 1 mm in an optic. We confirmed detection and localization of 3 mm and 5 mm features in experimental data, and a 0.5 mm in simulated data with sufficiently high signal-to-noise ratio. We present the theory, experimental results, and simulated results.

  14. INNOVATIVE ACOUSTIC SENSOR TECHNOLOGIES FOR LEAK DETECTION IN CHALLENGING PIPE TYPES

    Science.gov (United States)

    2016-12-30

    Table 7.5. Cost Summary for Correlux Purchased for Periodic Inspections ............................... 41 Table 7.6. SIRs for Various Labor and...Maintenance • DPW operational labor cost • Contractor installation and setup cost • Annual service fee Periodic Inspection Deployed in a “lift and...14) Achieved 100% (14/14) Not Achieved 50% (7/14) Achieved 93% (13/14) Minimum detectable leak size Flow rate (gpm) Flow rate for known

  15. COST AND PERFORMANCE REPORT: INNOVATIVE ACOUSTIC SENSOR TECHNOLOGIES FOR LEAK DETECTION IN CHALLENGING PIPE TYPES

    Science.gov (United States)

    2016-12-30

    Summary for Correlux Purchased for Periodic Inspections ............................... 36 Table 7-6. SIRs for Various Labor and Water Cost (for...UEM) Sensors, Transmitters, Computer, Personal Data Assistant (PDA) • Capital equipment • Maintenance • DPW operational labor cost • Contractor...12/14) Achieved 100% (14/14) Not Achieved 50% (7/14) Achieved 93% (13/14) Minimum detectable leak size Flow rate (gpm) Flow rate for

  16. Fatigue Crack Detection at Gearbox Spline Component using Acoustic Emission Method

    Science.gov (United States)

    2014-10-02

    analytical understanding of gearmesh stiffness change with the tooth crack (Chaari et al. 2009, Chen and Shao 2011). Debris monitoring does not require...that the AE method is not sensitive to gear wear while the method detects the tooth crack earlier than the vibration method. Typical parameters...11-22. Chaari, F., Fakhfakh, T. and Haddar, M. (2009). “Analytical Modelling of Spur Gear Tooth Crack and Influence on Gearmesh Stiffness

  17. Automatic non-destructive three-dimensional acoustic coring system for in situ detection of aquatic plant root under the water bottom

    Directory of Open Access Journals (Sweden)

    Katsunori Mizuno

    2016-05-01

    Full Text Available Digging is necessary to detect plant roots under the water bottom. However, such detection is affected by the transparency of water and the working skills of divers, usually requires considerable time for high-resolution sampling, and always damages the survey site. We developed a new automatic non-destructive acoustic measurement system that visualizes the space under the water bottom, and tested the system in the in situ detection of natural plant roots. The system mainly comprises a two-dimensional waterproof stage controlling unit and acoustic measurement unit. The stage unit was electrically controlled through a notebook personal computer, and the space under the water bottom was scanned in a two-dimensional plane with the stage unit moving in steps of 0.01 m (±0.0001 m. We confirmed a natural plant root with diameter of 0.025–0.030 m in the reconstructed three-dimensional acoustic image. The plant root was at a depth of about 0.54 m and the propagation speed of the wave between the bottom surface and plant root was estimated to be 1574 m/s. This measurement system for plant root detection will be useful for the non-destructive assessment of the status of the space under the water bottom.

  18. All-fiber interferometric sensor of 150kHz acoustic emission for the detection of partial discharges within power transformers

    Science.gov (United States)

    Posada, Julio E.; Rubio-Serrano, Jesus; Garcia-Souto, Jose A.

    2011-05-01

    An all-fiber interferometric acoustic emission (AE) sensor was designed for partial discharges (PD) and characterized against typical PZT sensors (R15i). The device is based on a multi-layer fiber-optic probe and it is able to detect PD ultrasound emission at 150 kHz. It may be placed next to the discharge source immersed in oil - or as an ultrasonic hydrophone -, thus overcoming the difficulties of acoustic attenuation which are characteristic of the external detection on the walls. The device provides suitable narrowband acoustic detection of the PD activity, like the PZT transducers mounted on the exterior of the transformer tank. The results show similar sensitivity, but wider directivity of the fiberoptic sensor in order to inspect large zones within the tank. It represents a simple and cheap alternative for detecting AE and it is the base of a multi-channel heterodyne interferometer which will drive at least four sensors to provide information for locating the source.

  19. Acoustical gas-leak detection in the presence of multiple reflections, dispersion, and uncorrelated noise using optimized residual complexity.

    Science.gov (United States)

    Ahmadi, A M; Amjadi, A; Bahrampour, A R; Ravanbod, H; Tofighi, S

    2016-09-01

    Precise acoustical leak detection calls for robust time-delay estimates, which minimize the probability of false alarms in the face of dispersive propagation, multiple reflections, and uncorrelated background noise. Providing evidence that higher order modes and multi-reflected signals behave like sets of correlated noise, this work uses a regression model to optimize residual complexity in the presence of both correlated and uncorrelated noise. This optimized residual complexity (ORC) is highly robust since it takes into account both the level and complexity of noise. The lower complexity of the dispersive modes and multiple reflections, compared to the complexity of the plane mode, points to the robustness of ORC against multiple reflections and dispersion. Experimental investigations using recorded sounds of gas leaking from a pipe confirm the robustness of ORC against multiple reflections. Numerical simulations also show robustness against dispersive modes, even when they disturb the linearity of the cross-spectrum phase. Comparisons with other methods-mutual information, cross correlation, and residual complexity-underline the general advantages of ORC in terms of robustness in the presence of reflection and dispersion, against both correlated and uncorrelated noise, and to short signals.

  20. A new methodology for automating acoustic emission detection of metallic fatigue fractures in highly demanding aerospace environments: An overview

    Science.gov (United States)

    Holford, Karen M.; Eaton, Mark J.; Hensman, James J.; Pullin, Rhys; Evans, Sam L.; Dervilis, Nikolaos; Worden, Keith

    2017-04-01

    The acoustic emission (AE) phenomenon has many attributes that make it desirable as a structural health monitoring or non-destructive testing technique, including the capability to continuously and globally monitor large structures using a sparse sensor array and with no dependency on defect size. However, AE monitoring is yet to fulfil its true potential, due mainly to limitations in location accuracy and signal characterisation that often arise in complex structures with high levels of background noise. Furthermore, the technique has been criticised for a lack of quantitative results and the large amount of operator interpretation required during data analysis. This paper begins by introducing the challenges faced in developing an AE based structural health monitoring system and then gives a review of previous progress made in addresing these challenges. Subsequently an overview of a novel methodology for automatic detection of fatigue fractures in complex geometries and noisy environments is presented, which combines a number of signal processing techniques to address the current limitations of AE monitoring. The technique was developed for monitoring metallic landing gear components during pre-flight certification testing and results are presented from a full-scale steel landing gear component undergoing fatigue loading. Fracture onset was successfully identify automatically at 49,000 fatigue cycles prior to final failure (validated by the use of dye penetrant inspection) and the fracture position was located to within 10 mm of the actual location.

  1. Real-Time Characterization of Electrospun PVP Nanofibers as Sensitive Layer of a Surface Acoustic Wave Device for Gas Detection

    Directory of Open Access Journals (Sweden)

    D. Matatagui

    2014-01-01

    Full Text Available The goal of this work has been to study the polyvinylpyrrolidone (PVP fibers deposited by means of the electrospinning technique for using as sensitive layer in surface acoustic wave (SAW sensors to detect volatile organic compounds (VOCs. The electrospinning process of the fibers has been monitored and RF characterized in real time, and it has been shown that the diameters of the fibers depend mainly on two variables: the applied voltage and the distance between the needle and the collector, since all the electrospun fibers have been characterized by a scanning electron microscopy (SEM. Real-time measurement during the fiber coating process has shown that the depth of penetration of mechanical perturbation in the fiber layer has a limit. It has been demonstrated that once this saturation has been reached, the increase of the thickness of the fibers coating does not improve the sensitivity of the sensor. Finally, the parameters used to deposit the electrospun fibers of smaller diameters have been used to deposit fibers on a SAW device to obtain a sensor to measure different concentrations of toluene at room temperature. The present sensor exhibited excellent sensitivity, good linearity and repeatability, and high and fast response to toluene at room temperature.

  2. Historical detection of atmospheric impacts by large bolides using acoustic-gravity waves

    Energy Technology Data Exchange (ETDEWEB)

    ReVelle, D.O.

    1995-05-01

    During the period from about 1960 to the early 1980`s a number of large bolides (meteor-fireballs) entered the atmosphere which were sufficiently large to generate blast waves during their drag interaction with the air. For example, the remnant of the blast wave from a single kiloton class event was subsequently detected by up to six ground arrays of microbarographs which were operated by the U.S. Air Force during this pre-satellite period. Data have also been obtained from other sources during this period as well and are also discussed in this summary of the historical data. The Air Force data have been analyzed in terms of their observable properties in order to infer the influx rate of NEO`s (near-Earth objects) in the energy range from 0.2 to 1100 kt. The determined influx is in reasonable agreement with that determined by other methods currently available such as Rabinowitz (1992), Ceplecha, (1992; 1994b) and by Chapman and Morrison (1994) despite the fact that due to sampling deficiencies only a portion of the {open_quotes}true{close_quotes} flux of large bodies has been obtained by this method, i.e., only sources at relatively low elevations have been detected. Thus the weak, fragile cometary bodies which do not penetrate the atmosphere as deeply are less likely to have been sampled by this type of detection system. Future work using the proposed C.T.B.T. (Comprehensive Test Ban Treaty) global scale infrasonic network will be likely to improve upon this early estimate of the global influx of NEO`s considerably.

  3. Early detection of nucleate boiling and spectral analysis of acoustical noise

    International Nuclear Information System (INIS)

    Bouneder, M.

    1987-01-01

    The development of a reliable detection technique for the onset of boiling has been further pursued. Besides the already studied tube geometry, a more realistic annular set up has been used where a fuel pin model, electrically heated, is placed. Using accelerometers on the pin, on the structure and on specific instrumentation cables the onset of boiling was clearly monitored by the emergence of a typical resonance frequency. The influence of pressure and heat power was analysed in detail. Furthermore, a glass model has been constructed in order to better correlate the observed measurement with the boiling parameters, as bubble radius, frequency and collapse mode

  4. Acoustic and Doppler radar detection of buried land mines using high-pressure water jets

    Science.gov (United States)

    Denier, Robert; Herrick, Thomas J.; Mitchell, O. Robert; Summers, David A.; Saylor, Daniel R.

    1999-08-01

    The goal of the waterjet-based mine location and identification project is to find a way to use waterjets to locate and differentiate buried objects. When a buried object is struck with a high-pressure waterjets, the impact will cause characteristic vibrations in the object depending on the object's shape and composition. These vibrations will be transferred to the ground and then to the water stream that is hitting the object. Some of these vibrations will also be transferred to the air via the narrow channel the waterjet cuts in the ground. Currently the ground vibrations are detected with Doppler radar and video camera sensing, while the air vibrations are detected with a directional microphone. Data is collected via a Labview based data acquisition system. This data is then manipulated in Labview to produce the associated power spectrums. These power spectra are fed through various signal processing and recognition routines to determine the probability of there being an object present under the current test location and what that object is likely to be. Our current test area consists of a large X-Y positioning system placed over approximately a five-foot circular test area. The positioning system moves both the waterjet and the sensor package to the test location specified by the Labview control software. Currently we are able to locate buried land mine models at a distance of approximately three inches with a high degree of accuracy.

  5. On acoustic emission for damage detection and failure prediction in fiber reinforced polymer rods using pattern recognition analysis

    Science.gov (United States)

    Shateri, Mohammadhadi; Ghaib, Maha; Svecova, Dagmar; Thomson, Douglas

    2017-06-01

    Fiber reinforced polymer (FRP) rods are used for pre-stressing and reinforcing in civil engineering applications. Damage in FRP rods can lead to sudden brittle failure, therefore, a reliable method that provides indicators of damage progression and potential failure in FRP rods is highly desirable. Acoustic emission (AE) signal analysis has been used for damage detection and monitoring of FRP materials. In this study, a new AE event detection algorithm, utilizing the root mean square envelope of AE signal, is applied to AE data to isolate each AE event separately, even when AE events are nearly coincident. A fuzzy c-means (FCM) clustering algorithm is used to classify these isolated AE events into 3 clusters. Scanning electron microscopy images of FRP rod cross-sections also show 3 types of damage. The hypothesis in this study is that each cluster represents a damage mechanism. The number of events in each cluster is monitored versus the percent of the ultimate load. The ratio of the number of AE events in one of the FCM clusters to the number of AE events in another FCM cluster was useful for providing an indication of when the stress levels have reached the point where the loads may cause the FRP rod to fail. The results of applying this parameter to four FRP rods show a significant slope change (factor of 10) in this ratio at around 40% and 60% of the ultimate load for glass FRP rods and carbon FRP rods, respectively. This method may prove useful in damage progression and failure prediction of the FRP rods in prefabricated structures where pre-stressed FRP is used and in field monitoring of FRP materials.

  6. Acoustic detection of seabed gas leaks, with application to Carbon Capture and Storage (CCS), and leak prevention for the oil and gas industry

    OpenAIRE

    Berges, B.J.P.

    2015-01-01

    The acoustic remote sensing of subsea gas leakage, applied to the monitoring of underwater gas discharges from anthropogenic and natural sources, is becoming increasingly important. First, as the oil and gas industry is facing increasing regulation, there is a need to put more control in the industrial process and to assess the impact on the marine environment. The applications are diverse, including: early warnings of "blow-out" from offshore installations, detection of leaks from underwater...

  7. Automatic detection, segmentation and assessment of snoring from ambient acoustic data.

    Science.gov (United States)

    Duckitt, W D; Tuomi, S K; Niesler, T R

    2006-10-01

    Snoring is a prevalent condition with a variety of negative social effects and associated health problems. Treatments, both surgical and therapeutic, have been developed, but the objective non-invasive monitoring of their success remains problematic. We present a method which allows the automatic monitoring of snoring characteristics, such as intensity and frequency, from audio data captured via a freestanding microphone. This represents a simple and portable diagnostic alternative to polysomnography. Our system is based on methods that have proved effective in the field of speech recognition. Hidden Markov models (HMMs) were employed as basic elements with which to model different types of sound by means of spectrally based features. This allows periods of snoring to be identified, while rejecting silence, breathing and other sounds. Training and test data were gathered from six subjects, and annotated appropriately. The system was tested by requiring it to automatically classify snoring sounds in new audio recordings and then comparing the result with manually obtained annotations. We found that our system was able to correctly identify snores with 82-89% accuracy, despite the small size of the training set. We could further demonstrate how this segmentation can be used to measure the snoring intensity, snoring frequency and snoring index. We conclude that a system based on hidden Markov models and spectrally based features is effective in the automatic detection and monitoring of snoring from audio data.

  8. Multivariate data-driven modelling and pattern recognition for damage detection and identification for acoustic emission and acousto-ultrasonics

    DEFF Research Database (Denmark)

    Torres-Arredondo, M.A.; Tibaduiza, D.-A.; McGugan, Malcolm

    2013-01-01

    Different methods are commonly used for non-destructive testing in structures; among others, acoustic emission and ultrasonic inspections are widely used to assess structures. The research presented in this paper is motivated by the need to improve the inspection capabilities and reliability of s...... measurements and self-organizing maps, which are applied to data from acoustic emission tests and acousto-ultrasonic inspections. At the end, the efficiency of these methodologies is experimentally evaluated in diverse anisotropic composite structures....

  9. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....

  10. Acoustic telemetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To determine movements of green turtles in the nearshore foraging areas, we deployed acoustic tags and determined their movements through active and passive acoustic...

  11. Ensuring safe operation and assessing the condition underground structures by the method of acoustic resonance flaw detection

    Science.gov (United States)

    Meskhi, Besarion; Pleshko, Mikhail; Buligin, Yuriy; Alexeenko, Lyudmila; Molev, Mikhail

    2017-10-01

    In the article the main results of theoretical and experimental research in the field of nondestructive testing and forecasting of the geomechanical state of the dome part of transport tunnels. It is shown that for this purpose it is possible to apply the acoustic resonance defectoscopy method. The method of mine measurements consisted in fixing the forced oscillations of a multilayer carbon-rock massif with the shock initiation of a seismoacoustic signal. The excitation and reception of acoustic standing waves were carried out in the lower rock layer. The actual characteristics of the efficiency of the acoustic assessment of the state of the geoenvironment provide the authors the opportunity to recommend the described methodology for mass practical application in the transport tunnels.

  12. International Workshop on Detection, Classification and Localization of Marine Mammals Using Passive Acoustics (4th). International Workshop on Density Estimation of Marine Mammals Using Passive Acoustics (1st)

    Science.gov (United States)

    2009-09-13

    Università degli Studi di Pavia Dipartimento di Biologia Animale Centro Interdisciplinare di Bioacustica e Ricerche Ambientali 4th International...Dipartimento di Biologia Animale Centro Interdisciplinare di Bioacustica e Ricerche Ambientali 4th International Workshop on Detection, Classification...mail: gianni.pavan@unipv.it ORGANIZED BY: Università degli Studi di Pavia - Dipartimento di Biologia Animale CIBRA CENTRO INTERDISCIPLINARE DI

  13. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers

    International Nuclear Information System (INIS)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-01-01

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  14. Acoustic cloaking and transformation acoustics

    Energy Technology Data Exchange (ETDEWEB)

    Chen Huanyang [School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006 (China); Chan, C T, E-mail: kenyon@ust.h, E-mail: phchan@ust.h [Department of Physics and the William Mong Institute of NanoScience and Technology, The Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong)

    2010-03-24

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  15. Acoustical Imaging

    CERN Document Server

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  16. Acoustic textiles

    CERN Document Server

    Nayak, Rajkishore

    2016-01-01

    This book highlights the manufacturing and applications of acoustic textiles in various industries. It also includes examples from different industries in which acoustic textiles can be used to absorb noise and help reduce the impact of noise at the workplace. Given the importance of noise reduction in the working environment in several industries, the book offers a valuable guide for companies, educators and researchers involved with acoustic materials.

  17. Detection of baryon acoustic oscillation features in the large-scale three-point correlation function of SDSS BOSS DR12 CMASS galaxies

    Science.gov (United States)

    Slepian, Zachary; Eisenstein, Daniel J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Gil-Marín, Héctor; Ho, Shirley; Kitaura, Francisco-Shu; Percival, Will J.; Ross, Ashley J.; Rossi, Graziano; Seo, Hee-Jong; Slosar, Anže; Vargas-Magaña, Mariana

    2017-08-01

    We present the large-scale three-point correlation function (3PCF) of the Sloan Digital Sky Survey DR12 Constant stellar Mass (CMASS) sample of 777 202 Luminous Red Galaxies, the largest-ever sample used for a 3PCF or bispectrum measurement. We make the first high-significance (4.5σ) detection of baryon acoustic oscillations (BAO) in the 3PCF. Using these acoustic features in the 3PCF as a standard ruler, we measure the distance to z = 0.57 to 1.7 per cent precision (statistical plus systematic). We find DV = 2024 ± 29 Mpc (stat) ± 20 Mpc (sys) for our fiducial cosmology (consistent with Planck 2015) and bias model. This measurement extends the use of the BAO technique from the two-point correlation function (2PCF) and power spectrum to the 3PCF and opens an avenue for deriving additional cosmological distance information from future large-scale structure redshift surveys such as DESI. Our measured distance scale from the 3PCF is fairly independent from that derived from the pre-reconstruction 2PCF and is equivalent to increasing the length of BOSS by roughly 10 per cent; reconstruction appears to lower the independence of the distance measurements. Fitting a model including tidal tensor bias yields a moderate-significance (2.6σ) detection of this bias with a value in agreement with the prediction from local Lagrangian biasing.

  18. Acoustic emission intrusion detector

    International Nuclear Information System (INIS)

    Carver, D.W.

    1978-01-01

    In order to improve the security of handling special nuclear materials at the Oak Ridge Y-12 Plant, a sensitive acoustic emission detector has been developed that will detect forcible entry through block or tile walls, concrete floors, or concrete/steel vault walls. A small, low-powered processor was designed to convert the output from a sensitive, crystal-type acoustic transducer to an alarm relay signal for use with a supervised alarm loop. The unit may be used to detect forcible entry through concrete, steel, block, tile, and/or glass

  19. Acoustic Emission Technology and Application

    International Nuclear Information System (INIS)

    Joo, Y. S.; Lim, S. H.; Eom, H. S.; Kim, J. H.; Jung, H. K.

    2003-10-01

    Acoustic emission is the elastic wave that is generated by the rapid release of energy from the localized sources within a material. After the observation of acoustic emission phenomenon in 1950, the research and further investigation had been performed. Acoustic emission examination becomes a rapidly matured nondestructive testing method with demonstrated capabilities for characterizing material behavior and for detecting the defect. It is of interest as a possible passive monitoring technique for detecting, locating and characterizing the defects in component and structure. Acoustic emission technology has recently strengthened the on-line monitoring application for the detection of incipient failures and the assurance of structural integrity. The field of acoustic emission testing is still growing vigorously and presents many challenges. Especially, acoustic emission has been successfully applied in the leak detection of primary pressure boundary of nuclear power plants. In this state-of-art report, the principle, measurement and field applications of acoustic emission technique is reviewed and summarized. Acoustic emission technology will contribute to the assurance of nuclear safety as the on-line monitoring technique of structural integrity of NSSS components and structures

  20. A Study on the Application of Acoustic Emission Measurement for the In-process Detection of Milling Tools' Wear and Chipping

    International Nuclear Information System (INIS)

    Yoon, J. H.; Kang, M. S.

    1991-01-01

    Acoustic emission(AE) signals detected during metal cutting were applied as the experimental test to sensing tool wear and chipping on the NC vertical milling machine. The in-process detection of cutting tool wear including chipping, cracking and fracture has been investigated by means of AE in spite of vibration or noise through intermittent metal cutting, then the following results were obtained 1) When the tool wear is increased suddenly, or the amplitude of AE signals changes largely, it indicates chipping or breaking of the insert tip. 2) It was confirmed that AE signal is highly sensitive to the cutting speed and tool wear. 3) At the early period of cutting, the wear were large and RMS value increased highly by the influence of minute chipping and cracking, etc. Therefore, the above situations should be considered for the time when the tool would be changed

  1. Noise Trauma-Induced Behavioral Gap Detection Deficits Correlate with Reorganization of Excitatory and Inhibitory Local Circuits in the Inferior Colliculus and Are Prevented by Acoustic Enrichment.

    Science.gov (United States)

    Sturm, Joshua J; Zhang-Hooks, Ying-Xin; Roos, Hannah; Nguyen, Tuan; Kandler, Karl

    2017-06-28

    Hearing loss leads to a host of cellular and synaptic changes in auditory brain areas that are thought to give rise to auditory perception deficits such as temporal processing impairments, hyperacusis, and tinnitus. However, little is known about possible changes in synaptic circuit connectivity that may underlie these hearing deficits. Here, we show that mild hearing loss as a result of brief noise exposure leads to a pronounced reorganization of local excitatory and inhibitory circuits in the mouse inferior colliculus. The exact nature of these reorganizations correlated with the presence or absence of the animals' impairments in detecting brief sound gaps, a commonly used behavioral sign for tinnitus in animal models. Mice with gap detection deficits (GDDs) showed a shift in the balance of synaptic excitation and inhibition that was present in both glutamatergic and GABAergic neurons, whereas mice without GDDs showed stable excitation-inhibition balances. Acoustic enrichment (AE) with moderate intensity, pulsed white noise immediately after noise trauma prevented both circuit reorganization and GDDs, raising the possibility of using AE immediately after cochlear damage to prevent or alleviate the emergence of central auditory processing deficits. SIGNIFICANCE STATEMENT Noise overexposure is a major cause of central auditory processing disorders, including tinnitus, yet the changes in synaptic connectivity underlying these disorders remain poorly understood. Here, we find that brief noise overexposure leads to distinct reorganizations of excitatory and inhibitory synaptic inputs onto glutamatergic and GABAergic neurons and that the nature of these reorganizations correlates with animals' impairments in detecting brief sound gaps, which is often considered a sign of tinnitus. Acoustic enrichment immediately after noise trauma prevents circuit reorganizations and gap detection deficits, highlighting the potential for using sound therapy soon after cochlear damage

  2. Development of Highly Sensitive Bulk Acoustic Wave Device Biosensor Arrays for Screening and Early Detection of Prostate Cancer

    Science.gov (United States)

    2008-01-01

    be controlled via USB connection to a laptop running NI LabVIEW software allowing sensor array to be monitored via SMA connection. 13 Key Research...grown on a p- doped 1 0 0 Si substrate with ZnO as the active piezoelectric layer at the surface. The acoustic mirror was designed to have a reflection...functionalization of ITO electrodes for development of electrochemical sensors 20 and for modifying TiO2, BaTiO3 , and ZnO particles 21-23. In another study

  3. Radiation acoustics

    CERN Document Server

    Lyamshev, Leonid M

    2004-01-01

    Radiation acoustics is a developing field lying at the intersection of acoustics, high-energy physics, nuclear physics, and condensed matter physics. Radiation Acoustics is among the first books to address this promising field of study, and the first to collect all of the most significant results achieved since research in this area began in earnest in the 1970s.The book begins by reviewing the data on elementary particles, absorption of penetrating radiation in a substance, and the mechanisms of acoustic radiation excitation. The next seven chapters present a theoretical treatment of thermoradiation sound generation in condensed media under the action of modulated penetrating radiation and radiation pulses. The author explores particular features of the acoustic fields of moving thermoradiation sound sources, sound excitation by single high-energy particles, and the efficiency and optimal conditions of thermoradiation sound generation. Experimental results follow the theoretical discussions, and these clearl...

  4. Detecting the Activation of a Self-Healing Mechanism in Concrete by Acoustic Emission and Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    E. Tsangouri

    2013-01-01

    Full Text Available Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

  5. Multi-bearing weak defect detection for wayside acoustic diagnosis based on a time-varying spatial filtering rearrangement

    Science.gov (United States)

    Zhang, Shangbin; He, Qingbo; Ouyang, Kesai; Xiong, Wei

    2018-02-01

    The wayside Acoustic Defective Bearing Detector (ADBD) system plays an important role in ensuring the safety of railway transportation. However, Doppler distortion and multi-bearing source aliasing in the acquired acoustic bearing signals significantly decrease the accuracy of bearing diagnosis. Traditional multisource separation schemes using time-frequency filters constructed by a single microphone signal always show poor performance on weak signal separation. Inspired by an assumption that the spatial location of different sources is different, this paper proposes a novel time-varying spatial filtering rearrangement (TSFR) scheme based on a microphone array to overcome current difficulties. In the scheme, a zero-angle spatial filter and peak searching are proposed to obtain the time-centers of corresponding sources. Based on these time-centers, several time-varying spatial filters are designed to extract different source signals. Then interpolation and rearrangement are used to correct the Doppler distortion and reconstruct the corresponding separated signals. Finally, the train bearing fault diagnosis is implemented by analyzing the envelope spectrum of the corrected signals. Because the time-varying spatial filter construction is only dependent on the source location and has little relationship with the signal energy, the proposed TSFR scheme has significant advantages in weak signal separation and diagnosis in comparison with traditional ones. With the verifications by both simulation and experiment cases, the proposed array-based TSFR scheme shows a good performance on multiple fault source separation and is expected to be used in the ADBD system.

  6. On the acoustic filtering of the pipe and sensor in a buried plastic water pipe and its effect on leak detection: an experimental investigation.

    Science.gov (United States)

    Almeida, Fabrício; Brennan, Michael; Joseph, Phillip; Whitfield, Stuart; Dray, Simon; Paschoalini, Amarildo

    2014-03-20

    Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors.

  7. Terahertz acoustic phonon detection from a compact surface layer of spherical nanoparticles powder mixture of aluminum, alumina and multi-walled carbon nanotube

    Science.gov (United States)

    Abouelsayed, A.; Ebrahim, M. R.; El hotaby, W.; Hassan, S. A.; Al-Ashkar, Emad

    2017-10-01

    We present terahertz spectroscopy study on spherical nanoparticles powder mixture of aluminum, alumina, and MWCNTs induced by surface mechanical attrition treatment (SMAT) of aluminum substrates. Surface alloying of AL, Al2O3 0.95% and MWCNTs 0.05% powder mixture was produced during SMAT process, where a compact surface layer of about 200 μm due to ball bombardment was produced from the mixture. Al2O3 alumina powder played a significant role in MWCNTs distribution on surface, those were held in deformation surface cites of micro-cavities due to SMAT process of Al. The benefits are the effects on resulted optical properties of the surface studied at the terahertz frequency range due to electrical isolation confinement effects and electronic resonance disturbances exerted on Al electronic resonance at the same range of frequencies. THz acoustic phonon around 0.53-0.6 THz (17-20 cm-1) were observed at ambient conditions for the spherical nanoparticles powder mixture of Al, Al2O3 and MWCNTs. These results suggested that the presence of Al2O3 and MWCNTs during SMAT process leads to the optically detection of such acoustic phonon in the THz frequency range.

  8. The use of cluster analysis method for the localization of acoustic emission sources detected during the hydrotest of PWR pressure vessels

    International Nuclear Information System (INIS)

    Liska, J.; Svetlik, M.; Slama, K.

    1982-01-01

    The acoustic emission method is a promising tool for checking reactor pressure vessel integrity. Localization of emission sources is the first and the most important step in processing emission signals. The paper describes the emission sources localization method which is based on cluster analysis of a set of points depicting the emission events in the plane of coordinates of their occurrence. The method is based on using this set of points for constructing the minimum spanning tree and its partition into fragments corresponding to point clusters. Furthermore, the laws are considered of probability distribution of the minimum spanning tree edge length for one and several clusters with the aim of finding the optimum length of the critical edge for the partition of the tree. Practical application of the method is demonstrated on localizing the emission sources detected during a hydrotest of a pressure vessel used for testing the reactor pressure vessel covers. (author)

  9. Digital image correlation, acoustic emission and ultrasonic pulse velocity for the detection of cracks in the concrete buffer of the Belgian nuclear supercontainer

    International Nuclear Information System (INIS)

    Iliopoulos, Sokratis; Tsangouri, Eleni; Aggelis, Dimitrios G.; Pyl, Lincy; Areias, Lou; Vrije Univ., Brussels

    2014-01-01

    The long term management of high-level and heat emitting radioactive waste is a worldwide concern, as it directly influences the environment and future generations. To address this issue, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials has come up with the conceptual design of a massive concrete structure called Supercontainer. The feasibility to construct these structures is being evaluated through a number of scaled models that are tested using classical as well as state of the art measurement techniques. In the current paper, the results obtained from the simultaneous application of the Digital Image Correlation (DIC), the Acoustic Emission (AE) and the Ultrasonic Pulse Velocity (UPV) nondestructive testing techniques on the second scaled model for the detection and monitoring of cracks will be presented.

  10. Acoustic Neuroma

    Science.gov (United States)

    ... a team composed of neurosurgeons, radiation oncologists, medical physicists and a nursing staff. Specialists in neuroimaging join ... Even though most acoustic neuromas arise from the balance nerve (and not from the adjacent hearing nerve), ...

  11. Acoustic neuroma

    Science.gov (United States)

    ... Medical Professional Call your provider if you have: Hearing loss that is sudden or getting worse Ringing in one ear Dizziness (vertigo) Alternative Names Vestibular schwannoma; Tumor - acoustic; ... Patient Instructions Brain surgery - discharge ...

  12. Acoustics Research

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....

  13. Acoustical Imaging

    CERN Document Server

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  14. Room Acoustics

    Science.gov (United States)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  15. Fundamental study on leak detection of underground gas pipeline using passive acoustic method; Judogata onkyo keisoku ni yoru maisetsu gas dokan hason kasho no kenshutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Jinguji, M.; Imaizumi, H.; Kunimatsu, S.; Isei, T. [National Institute for Resources and Environment, Tsukuba (Japan)

    1997-05-27

    With an objective to detect gas leaking from an underground gas pipeline, discussions have been given on a method which utilizes acoustic characteristics of leakage. On leaking sound generated from damaged portions, the form of damaging was hypothesized as pinholes, and spectra of leaking sounds from holes with different diameters were measured. The dominant frequency decreases as the hole diameter increases, while it is in a region of relatively high frequency of 1 kHz or higher. However, detection from the ground surface was impossible when cover soil has thickness from 0.5 to 1.5 m. In an experiment to measure leaking sound inside the pipe, pressure in the pipe was adjusted to 0.02 atm which is a standard pressure for a low-pressure pipe, and the sound was measured when the hole diameters were varied. In any of the results obtained by varying the hole diameter, spectra having the dominant frequency in the region of 1 kHz or higher were measured. In addition, it was found that sound pressure difference of as much as 50 dB at maximum is generated as compared with a case of no sound leakage. The above results verified that monitoring the high frequency of 1 kHz or higher is effective in detecting leakage from small damages. 2 refs., 4 figs.

  16. Passive vibro-acoustic detection of a sodium-water reaction in a steam generator of a sodium-cooled fast neutrons nuclear reactor by beam forming

    International Nuclear Information System (INIS)

    Moriot, Jeremy

    2013-01-01

    This thesis deals with a new method to detect a sodium-water reaction in a steam generator of a fast sodium-cooled nuclear reactor. More precisely, the objective is to detect a micro-leak of water (flow ≤ 1 g/s) in less than 10 seconds by measuring the external shell vibrations of the component. The strong background noise in operation makes impossible the use of a detection system based on a threshold overrun. A beam forming method applied to vibrations measured by a linear array of accelerometers is developed in this thesis to increase the signal-to-noise ratio and to detect and locate the leak in the steam generator. A numerical study is first realized. Two models are developed in order to simulate the signals measured by the accelerometers of the array. The performances of the beam forming are then studied in function of several parameters, such as the source location and frequency, the damping factor, the background noise considered. The first model consists in an infinite plate in contact with a heavy fluid, excited by an acoustic monopole located in this fluid. Analyzing the transverse displacements in the wavenumber domain is useful to establish a criterion to sample correctly the vibration field of the plate. A second model, more representative of the system is also proposed. In this model, an elastic infinite cylindrical shell, filled with a heavy fluid is considered. The finite dimensions in the radial and circumferential directions lead to a modal behavior of the system which impacts the beam forming. Finally, the method is tested on an experimental mock-up which consists in a cylindrical pipe made in stainless steel and filled with water connected to hydraulic circuit. The water flow speed can be controlled by varying the speed of the pump. The acoustic source is generated by a hydro-phone. The performances of the beam forming are studied for different water flow speeds and different amplitude and frequencies of the source. (author) [fr

  17. A novel five-wire micro anemometer with 3D directionality for low speed air flow detection and acoustic particle velocity detecting capability

    Science.gov (United States)

    Li, Zhe; Chang, Wenhan; Gao, Chengchen; Hao, Yilong

    2018-04-01

    In this paper, a novel five-wire micro-fabricated anemometer with 3D directionality based on calorimetric principle is proposed, which is capable of measuring low speed airflow. This structure is realized by vertically bonding two different dies, which can be fabricated on the same wafer resulting in a simple fabrication process. Experiments on speed lower than 200 mm s‑1 are conducted, showing good repeatability and directionality. The speed of airflow is controlled by the volumetric flow rate. The measured velocity sensitivity is 9.4 mV · s m‑1, with relative direction sensitivity of 37.1 dB. The deviation between the expected and the measured directivity is analyzed by both theories and simulations. A correction procedure is proposed and turns out to be useful to eliminate this deviation. To further explore the potential of our device, we expose it to acoustic plane waves in a standing wave tube, showing consistent planar directivity of figure of eight. The measured velocity sensitivity at 1 kHz and 120 dBC is 4.4 mV · s m‑1, with relative direction sensitivity of 27.0 dB. By using the correction method proposed above, the maximum angle error is about  ±2°, showing its good directionality accuracy.

  18. Acoustic emission

    Indian Academy of Sciences (India)

    3Universidade do Minho, Department Engineering Mecânica, Azurém,. 4800058 Guimar˜aes, Portugal e-mail: mathew@dem.uminho.pt. Abstract. Acoustic Emission (AE) has been widely used for monitoring man- ufacturing processes particularly those involving metal cutting. Monitoring the condition of the cutting tool in the ...

  19. Confirmation of the detection and classification of low-order, low-degree solar acoustic modes with the 1978 solar diameter observations

    International Nuclear Information System (INIS)

    Hill, H.A.; Caudell, T.P.

    1985-01-01

    The 1978 solar diameter observations of Caudell et al. (1980) have been examined for evidence of the low-order, low-degree acoustic modes found by Hill (1984) in the 1979 observations of Bos and Hill (1983). The 1978 power spectrum was tested for evidence of (1) a nonrandom distribution of peaks relative to the eigenfrequency spectrum found by Hill (1984), (2) spatial symmetry properties of the eigenfunctions for the modes classified by Hill (1984), and (3) a theta-dependence, specified by angular order m, of the amplitudes of oscillations for these same modes. The characterization of the symmetry properties of the eigenfunctions and the values of m were taken from the work of Hill (1984). The findings of these three tests confirm the detection of modes and their classifications as given by Hill (1984). These three tests are independent of each other and, when combined, furnish a confirmation of considerable statistical significance. In addition, these modes are found to be randomly excited; the average intrinsic line widths for the n = 1, l = 6, 8, 10, and 12 modes are > or =0.01 μHz

  20. Leaf xylem embolism, detected acoustically and by cryo-SEM, corresponds to decreases in leaf hydraulic conductance in four evergreen species.

    Science.gov (United States)

    Johnson, Daniel M; Meinzer, Frederick C; Woodruff, David R; McCulloh, Katherine A

    2009-07-01

    Hydraulic conductance of leaves (K(leaf)) typically decreases with increasing water stress. However, the extent to which the decrease in K(leaf) is due to xylem cavitation, conduit deformation or changes in the extra-xylary pathway is unclear. We measured K(leaf) concurrently with ultrasonic acoustic emission (UAE) in dehydrating leaves of two vessel-bearing and two tracheid-bearing species to determine whether declining K(leaf) was associated with an accumulation of cavitation events. In addition, images of leaf internal structure were captured using cryo-scanning electron microscopy, which allowed detection of empty versus full and also deformed conduits. Overall, K(leaf) decreased as leaf water potentials (Psi(L)) became more negative. Values of K(leaf) corresponding to bulk leaf turgor loss points ranged from 13 to 45% of their maximum. Additionally, Psi(L) corresponding to a 50% loss in conductivity and 50% accumulated UAE ranged from -1.5 to -2.4 MPa and from -1.1 to -2.8 MPa, respectively, across species. Decreases in K(leaf) were closely associated with accumulated UAE and the percentage of empty conduits. The mean amplitude of UAEs was tightly correlated with mean conduit diameter (R(2) = 0.94, P = 0.018). These results suggest that water stress-induced decreases in K(leaf) in these species are directly related to xylem embolism.

  1. The Development of a Plan for the Assessment, Improvement and Deployment of a Radar Acoustic Sounding System (RASS) for Wake Vortex Detection

    Science.gov (United States)

    Morris, Philip J.; McLaughlin, Dennis K.; Gabrielson, Thomas B.; Boluriaan, Said

    2004-01-01

    This report describes the activities completed under a grant from the NASA Langley Research Center to develop a plan for the assessment, improvement, and deployment of a Radar Acoustic Sounding System (RASS) for the detection of wake vortices. A brief review is provided of existing alternative instruments for wake vortex detection. This is followed by a review of previous implementations and assessment of a RASS. As a result of this review, it is concluded that the basic features of a RASS have several advantages over other commonly used wake vortex detection and measurement systems. Most important of these features are the good fidelity of the measurements and the potential for all weather operation. To realize the full potential of this remote sensing instrument, a plan for the development of a RASS designed specifically for wake vortex detection and measurement has been prepared. To keep costs to a minimum, this program would start with the development an inexpensive laboratory-scale version of a RASS system. The new instrument would be developed in several stages, each allowing for a critical assessment of the instrument s potential and limitations. The instrument, in its initial stages of development, would be tested in a controlled laboratory environment. A jet vortex simulator, a prototype version of which has already been fabricated, would be interrogated by the RASS system. The details of the laboratory vortex would be measured using a Particle Image Velocimetry (PIV) system. In the early development stages, the scattered radar signal would be digitized and the signal post-processed to determine how extensively and accurately the RASS could measure properties of the wake vortex. If the initial tests prove to be successful, a real-time, digital signal processing system would be developed as a component of the RASS system. At each stage of the instrument development and testing, the implications of the scaling required for a full-scale instrument would be

  2. Acoustic surveillance techniques for SGU leak monitoring

    International Nuclear Information System (INIS)

    McKnight, J.A.; Rowley, R.; Beesley, M.J.

    1990-01-01

    The paper presents a brief review of the acoustic techniques applicable to the detection of steam generator unit leaks that have been studied in the UK. Before discussion of the acoustic detection methods a reference representation of the required performance as developed in the UK is given. The conclusion is made that preliminary specification for the acoustic leak detection of sodium/water leaks in steam generating units suggests that it will be necessary to detect better than a leak rate of 3 g/s within a few seconds. 10 refs, 12 figs

  3. Food intake monitoring: an acoustical approach to automated food intake activity detection and classification of consumed food

    International Nuclear Information System (INIS)

    Päßler, Sebastian; Fischer, Wolf-Joachim; Wolff, Matthias

    2012-01-01

    Obesity and nutrition-related diseases are currently growing challenges for medicine. A precise and timesaving method for food intake monitoring is needed. For this purpose, an approach based on the classification of sounds produced during food intake is presented. Sounds are recorded non-invasively by miniature microphones in the outer ear canal. A database of 51 participants eating seven types of food and consuming one drink has been developed for algorithm development and model training. The database is labeled manually using a protocol with introductions for annotation. The annotation procedure is evaluated using Cohen's kappa coefficient. The food intake activity is detected by the comparison of the signal energy of in-ear sounds to environmental sounds recorded by a reference microphone. Hidden Markov models are used for the recognition of single chew or swallowing events. Intake cycles are modeled as event sequences in finite-state grammars. Classification of consumed food is realized by a finite-state grammar decoder based on the Viterbi algorithm. We achieved a detection accuracy of 83% and a food classification accuracy of 79% on a test set of 10% of all records. Our approach faces the need of monitoring the time and occurrence of eating. With differentiation of consumed food, a first step toward the goal of meal weight estimation is taken. (paper)

  4. PVT Degradation Studies: Acoustic Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Dib, Gerges [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tucker, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-01

    Under certain environmental conditions, polyvinyl toluene (PVT) plastic scintillator has been observed to undergo internal fogging. This document reports on a study of acoustic techniques to determine whether they can provide a diagnostic for the fogging of PVT. Different ultrasound techniques were employed for detecting the level of internal fogging in PVT, including wave velocity measurements, attenuation, nonlinear acoustics, and acoustic microscopy. The results indicate that there are linear relations between the wave velocity and wave attenuation with the level of internal fogging. The effects of fogging on ultrasound wave attenuation is further verified by acoustic microscopy imaging, where regions with fog in the specimen demonstration higher levels of attenuation compared to clear regions. Results from the nonlinear ultrasound measurements were inconclusive due to high sensitivities to transducer coupling and fixture variabilities.

  5. A method for reduction of Acoustic Emission (AE) data with application in machine failure detection and diagnosis

    Science.gov (United States)

    Vicuña, Cristián Molina; Höweler, Christoph

    2017-12-01

    The use of AE in machine failure diagnosis has increased over the last years. Most AE-based failure diagnosis strategies use digital signal processing and thus require the sampling of AE signals. High sampling rates are required for this purpose (e.g. 2 MHz or higher), leading to streams of large amounts of data. This situation is aggravated if fine resolution and/or multiple sensors are required. These facts combine to produce bulky data, typically in the range of GBytes, for which sufficient storage space and efficient signal processing algorithms are required. This situation probably explains why, in practice, AE-based methods consist mostly in the calculation of scalar quantities such as RMS and Kurtosis, and the analysis of their evolution in time. While the scalar-based approach offers the advantage of maximum data reduction; it has the disadvantage that most part of the information contained in the raw AE signal is lost unrecoverably. This work presents a method offering large data reduction, while keeping the most important information conveyed by the raw AE signal, useful for failure detection and diagnosis. The proposed method consist in the construction of a synthetic, unevenly sampled signal which envelopes the AE bursts present on the raw AE signal in a triangular shape. The constructed signal - which we call TriSignal - also permits the estimation of most scalar quantities typically used for failure detection. But more importantly, it contains the information of the time of occurrence of the bursts, which is key for failure diagnosis. Lomb-Scargle normalized periodogram is used to construct the TriSignal spectrum, which reveals the frequency content of the TriSignal and provides the same information as the classic AE envelope. The paper includes application examples in planetary gearbox and low-speed rolling element bearing.

  6. Acoustic Territoriality

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2011-01-01

    Under the heading of "Gang i København" a number of initiatives was presented by the Lord Mayer and the Technical and Environmental Mayer of Copenhagen in May 2006. The aim of the initiative, which roughly translates to Lively Copenhagen, was both to make Copenhagen a livelier city in terms of ci...... this article outline a few approaches to a theory of acoustic territoriality....

  7. Automatic detection of wheezes by evaluation of multiple acoustic feature extraction methods and C-weighted SVM

    Science.gov (United States)

    Sosa, Germán. D.; Cruz-Roa, Angel; González, Fabio A.

    2015-01-01

    This work addresses the problem of lung sound classification, in particular, the problem of distinguishing between wheeze and normal sounds. Wheezing sound detection is an important step to associate lung sounds with an abnormal state of the respiratory system, usually associated with tuberculosis or another chronic obstructive pulmonary diseases (COPD). The paper presents an approach for automatic lung sound classification, which uses different state-of-the-art sound features in combination with a C-weighted support vector machine (SVM) classifier that works better for unbalanced data. Feature extraction methods used here are commonly applied in speech recognition and related problems thanks to the fact that they capture the most informative spectral content from the original signals. The evaluated methods were: Fourier transform (FT), wavelet decomposition using Wavelet Packet Transform bank of filters (WPT) and Mel Frequency Cepstral Coefficients (MFCC). For comparison, we evaluated and contrasted the proposed approach against previous works using different combination of features and/or classifiers. The different methods were evaluated on a set of lung sounds including normal and wheezing sounds. A leave-two-out per-case cross-validation approach was used, which, in each fold, chooses as validation set a couple of cases, one including normal sounds and the other including wheezing sounds. Experimental results were reported in terms of traditional classification performance measures: sensitivity, specificity and balanced accuracy. Our best results using the suggested approach, C-weighted SVM and MFCC, achieve a 82.1% of balanced accuracy obtaining the best result for this problem until now. These results suggest that supervised classifiers based on kernel methods are able to learn better models for this challenging classification problem even using the same feature extraction methods.

  8. Detección de perturbaciones en soldadura basado en el monitoreo de la acústica aerotransportada del proceso MIG / MAG Weld interferences detection based in airborne acoustical monitoring of MIG / MAG process

    Directory of Open Access Journals (Sweden)

    Eber Huanca Cayo

    2009-06-01

    Full Text Available El sonido del proceso de soldadura es una consecuencia de la modulación en amplitud de la corriente por la tensión del arco. Experimentaciones pasadas demostraron que un soldador experimentado tiene una dependencia absoluta de la acústica en el control del proceso de soldadura. En este trabajo se presenta una nueva técnica de detección de defectos de soldadura basada en la estabilidad de la acústica aerotransportada del proceso MIG/MAG para el modo de transferencia por corto-circuito. Se determinaron parámetros estadísticos de la presión acústica generada por el arco eléctrico del proceso de soldadura MIG/MAG en el modo de transferencia por corto-circuito a partir de múltiples soldaduras en posición plana sobre cuerpos de ensayo libres de defectos. Con estos resultados se desarrollo un algoritmo de detección de defectos basado en una ventana móvil que se desplaza a través de las señales estadísticas calculadas a partir de la acústica del proceso. Finalmente sobre un conjunto de cuerpos de prueba con y sin defectos fueron hechas soldaduras en posición plana para la evaluación del desempeño de la técnica de detección de defectos propuesta. El algoritmo de detección de defectos basado en la acústica aerotransportada del proceso, mostró resultados satisfactorios.The welding process's sound is a consequence of the modulation in amplitude of the current for the voltage of the electric arc. Previous experiments demonstrated that an experienced welder has an absolute dependence of the acoustics in the control of the welding process. In this work a new technique of detection of welding defects is presented based on the stability of the airborne acoustics of the process MIG/MAG for the transfer for short circuit mode. Statistical parameters of the acoustic pressure were determined and of the level of acoustic pressure for welding without defects from multiple tests; with these results have been development an algorithm of

  9. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Learn Back Learn about acoustic neuroma AN Facts What is acoustic neuroma? Diagnosing Symptoms Side Effects Keywords ... patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side effects Question ...

  10. Marine Acoustic Sensor Assembly

    National Research Council Canada - National Science Library

    Ruffa, Anthony A

    2007-01-01

    A marine acoustic sensor assembly includes an acoustic panel having a forward surface and an after surface, a laser scanner oriented so as to project a laser beam onto the acoustic panel after surface...

  11. The effects of two counterpropagating surface acoustic wave beams on single electron acoustic charge transport

    International Nuclear Information System (INIS)

    He Jianhong; Guo Huazhong; Song Li; Zhang Wei; Gao Jie; Lu Chuan

    2010-01-01

    We present a comprehensive study of the effects of two counterpropagating surface acoustic waves on the acoustoelectric current of single electron transport devices. A significant improvement in the accuracy of current quantization is achieved as a result of an additional surface acoustic wave beam. The experiments reveal the sinusoidally periodical modulation in the acoustoelectric current characteristic as a function of the relative phase of the two surface acoustic wave beams. Besides, by using standing surface acoustic waves, the acoustoelectric current is detected which we consider as the so-called anomalous acoustoelectric current produced by acoustic wave mechanical deformations. This kind current is contributed to one component of the acoustoelectric current in surface acoustic wave device, which could enable us to establish a more adequate description of acoustoelectric effects on single-electron acoustic charge transport.

  12. Acoustic emission from polycrystalline graphites

    International Nuclear Information System (INIS)

    Ioka, I.; Yoda, S.; Oku, T.; Miyamoto, Y.

    1987-01-01

    Acoustic emission was monitored from polycrystalline graphites with different microstructure (pore size and pore volume) subjected to compressive loading. The graphites used in this study comprised five brands, that is, PGX, ISEM-1, IG-11, IG-15, and ISO-88. A root mean square (RMS) voltage and event counts of acoustic emission for graphites were measured during compressive loading. The acoustic emission was measured using a computed-based data acquisition and analysis system. The graphites were first deformed up to 80 % of the average fracture stress, then unloaded and reloaded again until the fracture occured. During the first loading, the change in RMS voltage for acoustic emission was detected from the initial stage. During the unloading, the RMS voltage became zero level as soon as the applied stress was released and then gradually rose to a peak and declined. The behavior indicated that the reversed plastic deformation occured in graphites. During the second loading, the RMS voltage gently increased until the applied stress exceeded the maximum stress of the first loading; there is no Kaiser effect in the graphites. A bicrystal model could give a reasonable explanation of this results. The empirical equation between the ratio of σ AE to σ f and σ f was obtained. It is considered that the detection of microfracture by the acoustic emission technique is effective in macrofracture prediction of polycrystalline graphites. (author)

  13. Design Report for Low Power Acoustic Detector

    Science.gov (United States)

    2013-08-01

    the hardware design, target detection algorithm design in both MATLAB and VHDL , and typical performance results. 15. SUBJECT TERMS Acoustic low...diagram. .......................................................................................................3 Figure 4. HED VHDL block diagram...6 Figure 5. DCD VHDL block diagram

  14. Parametric Room Acoustic Workflows

    DEFF Research Database (Denmark)

    Parigi, Dario; Svidt, Kjeld; Molin, Erik

    2017-01-01

    and interoperability with Grasshopper 3d. The focus will be placed to the benchmarking of three different acoustic analysis tools based on raytracing. To compare the accuracy and speed of the acoustic evaluation across different tools, a homogeneous set of acoustic parameters is chosen. The room acoustics parameters...

  15. Organised Coherent Motion in Atmospheric Boundary Layer Flow in the Proximity to Tall Plant Canopies as Detected in Acoustic Doppler Profiler and Tower-based Observations

    Science.gov (United States)

    Foken, T.; Thomas, C. K.

    2007-12-01

    We investigated coherent structures above and in a tall plant canopy during a field campaign at a mountainous site in Germany (WALDATEM-2003). Data from a remote sensing acoustic Doppler system in concert with in-situ point measurements of turbulence in flow velocity and scalars deployed on towers yielded continuous observations from the forest ground to 200 m above the ground with a vertical resolution of 10 m at a sampling frequency of 0.4 and 20 Hz respectively. Coherent structures were extracted from time series utilizing wavelet transform techniques allowing for single structure analysis and averaged statistics of detected events. In addition to their spatiotemporal scales, we focused on the identification of generating mechanisms and surface parameters affecting coherent structures. Time scales were on the order of 20 to 36 s depending on the upstream topography and canopy morphology. Lateral transport dominated scalar coherent exchange. Vertical profiles of time scales in longitudinal and vertical velocities were mirror images showing an increase/ decrease, respectively, with height. Time scales in scalars were nearly height-constant. The ratio of the contribution of coherent structures to total vertical exchange was 0.2 for momentum and 0.25 to 0.4 for sensible heat. Analysis of power spectra confirmed an interaction between inactive eddies of atmospheric boundary layer scale and the horizontal flow in 4 % of all studied cases only, mainly under near-neutral stratification. Evaluation of the Mixing-Layer Analogy suggested that vertical shear caused by the immense canopy drag was the dominant generating mechanism. However, daytime coherent structures were found to be a superposition of shear generated events and convectional eddies. The latter led to an increase of vertical coherency in the flow around noon. At night, terrain induced linear gravity waves showed similar time scales as coherent structures emphasizing the need to differentiate between these two

  16. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    Energy Technology Data Exchange (ETDEWEB)

    John l. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

    2003-07-01

    The 1st generation acoustic monitoring package was designed to detect and analyze weak acoustic signals inside natural gas transmission lines. Besides a microphone it housed a three-inch diameter aerodynamic acoustic signal amplifier to maximize sensitivity to leak induced {Delta}p type signals. The theory and test results of this aerodynamic signal amplifier was described in the master's degree thesis of our Research Assistant Deepak Mehra who is about to graduate. To house such a large three-inch diameter sensor required the use of a steel 300-psi rated 4 inch weld neck flange, which itself weighed already 29 pounds. The completed 1st generation Acoustic Monitoring Package weighed almost 100 pounds. This was too cumbersome to mount in the field, on an access port at a pipeline shut-off valve. Therefore a 2nd generation and truly Portable Acoustic Monitor was built. It incorporated a fully self-contained {Delta}p type signal sensor, rated for line pressures up to 1000 psi with a base weight of only 6 pounds. This is the Rosemont Inc. Model 3051CD-Range 0, software driven sensor, which is believed to have industries best total performance. Its most sensitive unit was purchased with a {Delta}p range from 0 to 3 inch water. This resulted in the herein described 2nd generation: Portable Acoustic Monitoring Package (PAMP) for pipelines up to 1000 psi. Its 32-pound total weight includes an 18-volt battery. Together with a 3 pound laptop with its 4-channel data acquisition card, completes the equipment needed for field acoustic monitoring of natural gas transmission pipelines.

  17. Depth- and range-dependent variation in the performance of aquatic telemetry systems: understanding and predicting the susceptibility of acoustic tag-receiver pairs to close proximity detection interference.

    Science.gov (United States)

    Scherrer, Stephen R; Rideout, Brendan P; Giorli, Giacomo; Nosal, Eva-Marie; Weng, Kevin C

    2018-01-01

    Passive acoustic telemetry using coded transmitter tags and stationary receivers is a popular method for tracking movements of aquatic animals. Understanding the performance of these systems is important in array design and in analysis. Close proximity detection interference (CPDI) is a condition where receivers fail to reliably detect tag transmissions. CPDI generally occurs when the tag and receiver are near one another in acoustically reverberant settings. Here we confirm transmission multipaths reflected off the environment arriving at a receiver with sufficient delay relative to the direct signal cause CPDI. We propose a ray-propagation based model to estimate the arrival of energy via multipaths to predict CPDI occurrence, and we show how deeper deployments are particularly susceptible. A series of experiments were designed to develop and validate our model. Deep (300 m) and shallow (25 m) ranging experiments were conducted using Vemco V13 acoustic tags and VR2-W receivers. Probabilistic modeling of hourly detections was used to estimate the average distance a tag could be detected. A mechanistic model for predicting the arrival time of multipaths was developed using parameters from these experiments to calculate the direct and multipath path lengths. This model was retroactively applied to the previous ranging experiments to validate CPDI observations. Two additional experiments were designed to validate predictions of CPDI with respect to combinations of deployment depth and distance. Playback of recorded tags in a tank environment was used to confirm multipaths arriving after the receiver's blanking interval cause CPDI effects. Analysis of empirical data estimated the average maximum detection radius (AMDR), the farthest distance at which 95% of tag transmissions went undetected by receivers, was between 840 and 846 m for the deep ranging experiment across all factor permutations. From these results, CPDI was estimated within a 276.5 m radius of the

  18. Depth- and range-dependent variation in the performance of aquatic telemetry systems: understanding and predicting the susceptibility of acoustic tag–receiver pairs to close proximity detection interference

    Science.gov (United States)

    Rideout, Brendan P.; Giorli, Giacomo; Nosal, Eva-Marie

    2018-01-01

    Background Passive acoustic telemetry using coded transmitter tags and stationary receivers is a popular method for tracking movements of aquatic animals. Understanding the performance of these systems is important in array design and in analysis. Close proximity detection interference (CPDI) is a condition where receivers fail to reliably detect tag transmissions. CPDI generally occurs when the tag and receiver are near one another in acoustically reverberant settings. Here we confirm transmission multipaths reflected off the environment arriving at a receiver with sufficient delay relative to the direct signal cause CPDI. We propose a ray-propagation based model to estimate the arrival of energy via multipaths to predict CPDI occurrence, and we show how deeper deployments are particularly susceptible. Methods A series of experiments were designed to develop and validate our model. Deep (300 m) and shallow (25 m) ranging experiments were conducted using Vemco V13 acoustic tags and VR2-W receivers. Probabilistic modeling of hourly detections was used to estimate the average distance a tag could be detected. A mechanistic model for predicting the arrival time of multipaths was developed using parameters from these experiments to calculate the direct and multipath path lengths. This model was retroactively applied to the previous ranging experiments to validate CPDI observations. Two additional experiments were designed to validate predictions of CPDI with respect to combinations of deployment depth and distance. Playback of recorded tags in a tank environment was used to confirm multipaths arriving after the receiver’s blanking interval cause CPDI effects. Results Analysis of empirical data estimated the average maximum detection radius (AMDR), the farthest distance at which 95% of tag transmissions went undetected by receivers, was between 840 and 846 m for the deep ranging experiment across all factor permutations. From these results, CPDI was estimated within a

  19. Depth- and range-dependent variation in the performance of aquatic telemetry systems: understanding and predicting the susceptibility of acoustic tag–receiver pairs to close proximity detection interference

    Directory of Open Access Journals (Sweden)

    Stephen R. Scherrer

    2018-01-01

    Full Text Available Background Passive acoustic telemetry using coded transmitter tags and stationary receivers is a popular method for tracking movements of aquatic animals. Understanding the performance of these systems is important in array design and in analysis. Close proximity detection interference (CPDI is a condition where receivers fail to reliably detect tag transmissions. CPDI generally occurs when the tag and receiver are near one another in acoustically reverberant settings. Here we confirm transmission multipaths reflected off the environment arriving at a receiver with sufficient delay relative to the direct signal cause CPDI. We propose a ray-propagation based model to estimate the arrival of energy via multipaths to predict CPDI occurrence, and we show how deeper deployments are particularly susceptible. Methods A series of experiments were designed to develop and validate our model. Deep (300 m and shallow (25 m ranging experiments were conducted using Vemco V13 acoustic tags and VR2-W receivers. Probabilistic modeling of hourly detections was used to estimate the average distance a tag could be detected. A mechanistic model for predicting the arrival time of multipaths was developed using parameters from these experiments to calculate the direct and multipath path lengths. This model was retroactively applied to the previous ranging experiments to validate CPDI observations. Two additional experiments were designed to validate predictions of CPDI with respect to combinations of deployment depth and distance. Playback of recorded tags in a tank environment was used to confirm multipaths arriving after the receiver’s blanking interval cause CPDI effects. Results Analysis of empirical data estimated the average maximum detection radius (AMDR, the farthest distance at which 95% of tag transmissions went undetected by receivers, was between 840 and 846 m for the deep ranging experiment across all factor permutations. From these results, CPDI was

  20. Prototype acoustic resonance spectroscopy monitor

    International Nuclear Information System (INIS)

    Sinha, D.N.; Olinger, C.T.

    1996-03-01

    This report reports on work performed for the International Atomic Energy Agency (IAEA) through the Program Office for Technical Assistance (POTAS). In this work, we investigate possible applications of nondestructive acoustics measurements to facilitate IAEA safeguards at bulk processing facilities. Two different acoustic techniques for verifying the internal structure of a processing tank were investigated. During this effort we also examined two acoustic techniques for assessing the fill level within a processing tank. The fill-level measurements could be made highly portable and have an added safeguards advantage that they can also detect stratification of fill material. This later application may be particularly useful in confirming the absence of stratification in plutonium processing tanks before accountability samples are withdrawn

  1. Responsive acoustic surfaces

    DEFF Research Database (Denmark)

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design...... for the acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design...... was simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  2. Springer Handbook of Acoustics

    CERN Document Server

    Rossing, Thomas D

    2007-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese...

  3. Acoustic Neurinomas

    Directory of Open Access Journals (Sweden)

    Mohammad Faraji Rad

    2011-01-01

    Full Text Available Acoustic neuromas (AN are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(VS causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumor is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few. The predominant clinical endpoints of AN treatment include tumor control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL. It is uncertain if treating a small tumor leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment.   In this paper we review the literature for the natural course, the treatment alternatives and the results of AN. Finally, we present our experience with a management strategy applied for more than 30 years.

  4. Acoustic mapping as an environmental management tool: I. detection of barrels of low-level radioactive waste, Gulf of the Farallones National Marine Sanctuary, California

    Science.gov (United States)

    Karl, Herman A.; Schwab, William C.; Wright, A. St. C.; Drake, David E.; Chin, John L.; Danforth, William W.; Ueber, Edward

    1994-01-01

    The oceans have been and will continue to be disposal sites for a wide variety of waste products. Often these wastes are not dumped at the designated sites or transport occurs during or after dumping, and, subsequent attempts to monitor the effects the waste products have on the environment are inadequate because the actual location of the waste is not known. Acoustic mapping of the seafloor with sidescan sonar is a very effective technique for locating and monitoring dredge-spoil material and other debris. Sidescan sonar provides an acoustic image or sonograph of the sea floor that is similar to a satellite image of the Earth's land surface. In effect sidescan sonar allows the water column to be stripped from the sea floor, thereby providing a clear, unobstructed view of the sea bed.

  5. Detección de cavitación en una bomba centrífuga usando emisiones acústicas Cavitation detection in a centrifugal pump using acoustic emissions

    Directory of Open Access Journals (Sweden)

    Jabid Quiroga M.

    2012-12-01

    Full Text Available En el presente artículo se propone el uso de las emisiones acústicas para el monitoreo de la cavitación en una bomba centrífuga. Este monitoreo se ejecuta a través del seguimiento a unos indicadores de falla obtenidos a partir del valor RMS de la señal de emisiones acústicas en dominio tiempo y el valor RMS de los coeficientes de la Transformada Discreta Wavelet (TDW usando la onda madre db6 de la misma señal acústica. La experimentación se realiza en un banco dedicado que permite cavitar a una bomba de ½ hp en distintos niveles de severidad y bajo diferentes condiciones de bombeo. Resultados experimentales mostraron que los indicadores propuestos permiten detectar y evaluar cualitativamente los niveles de severidad de la cavitación en una bomba centrífuga.In this paper an acoustic emission based cavitation fault detection system is proposed for a centrifugal pump. The monitoring is performed tracking a fault indicator obtained using the RMS value of the acoustic emission signal in time domain and the RMS value of the coefficients obtained by applying discrete wavelet transform on the acoustic signal using db6 mother wavelet. Experiments in different cavitation levels and under different operation conditions are carried out in a ½ hp centrifugal pump dedicated test bed. Results showed that the proposed fault indicators are suitable for detecting and evaluating cavitation severities in a centrifugal pump.

  6. Responsive acoustic surfaces

    DEFF Research Database (Denmark)

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design...... was simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  7. Acoustics an introduction

    CERN Document Server

    Kuttruff, Heinrich

    2006-01-01

    This definitive textbook provides students with a comprehensive introduction to acoustics. Beginning with the basic physical ideas, Acoustics balances the fundamentals with engineering aspects, applications and electroacoustics, also covering music, speech and the properties of human hearing. The concepts of acoustics are exposed and applied in:room acousticssound insulation in buildingsnoise controlunderwater sound and ultrasoundScientifically thorough, but with mathematics kept to a minimum, Acoustics is the perfect introduction to acoustics for students at any level of mechanical, electrical or civil engineering courses and an accessible resource for architects, musicians or sound engineers requiring a technical understanding of acoustics and their applications.

  8. Acoustic Location of Lightning Using Interferometric Techniques

    Science.gov (United States)

    Erives, H.; Arechiga, R. O.; Stock, M.; Lapierre, J. L.; Edens, H. E.; Stringer, A.; Rison, W.; Thomas, R. J.

    2013-12-01

    Acoustic arrays have been used to accurately locate thunder sources in lightning flashes. The acoustic arrays located around the Magdalena mountains of central New Mexico produce locations which compare quite well with source locations provided by the New Mexico Tech Lightning Mapping Array. These arrays utilize 3 outer microphones surrounding a 4th microphone located at the center, The location is computed by band-passing the signal to remove noise, and then computing the cross correlating the outer 3 microphones with respect the center reference microphone. While this method works very well, it works best on signals with high signal to noise ratios; weaker signals are not as well located. Therefore, methods are being explored to improve the location accuracy and detection efficiency of the acoustic location systems. The signal received by acoustic arrays is strikingly similar to th signal received by radio frequency interferometers. Both acoustic location systems and radio frequency interferometers make coherent measurements of a signal arriving at a number of closely spaced antennas. And both acoustic and interferometric systems then correlate these signals between pairs of receivers to determine the direction to the source of the received signal. The primary difference between the two systems is the velocity of propagation of the emission, which is much slower for sound. Therefore, the same frequency based techniques that have been used quite successfully with radio interferometers should be applicable to acoustic based measurements as well. The results presented here are comparisons between the location results obtained with current cross correlation method and techniques developed for radio frequency interferometers applied to acoustic signals. The data were obtained during the summer 2013 storm season using multiple arrays sensitive to both infrasonic frequency and audio frequency acoustic emissions from lightning. Preliminary results show that

  9. ISAT: The mega-fauna acoustic tracking system

    KAUST Repository

    De la Torre, Pedro

    2013-06-01

    The acoustic tracking module of the Integrated Satellite and Acoustic Telemetry (iSAT) system is discussed in detail. iSAT is capable of detecting the relative direction of an acoustic source by measuring the order of arrival (OOA) of the acoustic signal to each hydrophone in a triangular array. The characteristics of the hydrophones, the projector, and the target acoustic signal used for iSAT are described. Initially it is designed to study the movements of whale sharks (Rhincodon typus), but it could potentially be used to describe high resolution movements of other marine species. © 2013 IEEE.

  10. Acoustic Holography

    Science.gov (United States)

    Kim, Yang-Hann

    One of the subtle problems that make noise control difficult for engineers is the invisibility of noise or sound. A visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical (or numerical) means for visualizing the sound field have been attempted, and as a result, a great deal of progress has been made. However, most of these numerical methods are not quite ready for practical applications to noise control problems. In the meantime, rapid progress with instrumentation has made it possible to use multiple microphones and fast signal-processing systems. Although these systems are not perfect, they are useful. A state-of-the-art system has recently become available, but it still has many problematic issues; for example, how can one implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently, it is often difficult to determine the origin of the noise and the spatial distribution of the noise field. Section 26.2 of this chapter introduces a brief history, which is associated with sound visualization, acoustic source identification methods and what has been accomplished with a line or surface array. Section 26.2.3 introduces difficulties and recent studies, including de-Dopplerization and de-re verberation methods, both essential for visualizing a moving noise source, such as occurs for cars or trains. This section also addresses what produces ambiguity in realizing real sound sources in a room or closed space. Another major issue associated with sound/noise visualization is whether or not we can distinguish between mutual dependencies of noise in space (Sect. 26.2.4); for example, we are asked to answer the question, Can we see two birds singing or one bird with two beaks?

  11. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Facts What is acoustic neuroma? Diagnosing Symptoms Side Effects Keywords Questions to ask Choosing a healthcare provider ... Surgery What is acoustic neuroma Diagnosing Symptoms Side effects Question To Ask Treatment Options Back Overview Observation ...

  12. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts What is acoustic ... Stories Keywords Shop ANA Discussion Forum About Back Learn more about ANA About ANA Mission, Vision & Values ...

  13. Atlantic Herring Acoustic Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and underwater...

  14. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... more Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN ... a Sponsor Patient Events Acoustic Neuroma Association Latest News Join / Renew Login Contact Us Become a Sponsor ...

  15. Novel Fiber-Optic Ring Acoustic Emission Sensor

    Directory of Open Access Journals (Sweden)

    Peng Wei

    2018-01-01

    Full Text Available Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

  16. Novel Fiber-Optic Ring Acoustic Emission Sensor.

    Science.gov (United States)

    Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

    2018-01-13

    Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

  17. Tutorial on architectural acoustics

    Science.gov (United States)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  18. World Conference on Acoustic Emission 2015

    CERN Document Server

    Wu, Zhanwen; Zhang, Junjiao

    2017-01-01

    This volume collects the papers from the World Conference on Acoustic Emission 2015 (WCAE-2015) in Hawaii. The latest research and applications of Acoustic Emission (AE) are explored, with particular emphasis on detecting and processing of AE signals, development of AE instrument and testing standards, AE of materials, engineering structures and systems, including the processing of collected data and analytical techniques as well as experimental case studies.

  19. World Conference on Acoustic Emission 2013

    CERN Document Server

    Wu, Zhanwen; Zhang, Junjiao

    2015-01-01

    This volume collects the papers from the 2013 World Conference on Acoustic Emission in Shanghai. The latest research and applications of Acoustic Emission (AE) are explored, with particular emphasis on detecting and processing of AE signals, development of AE instrument and testing standards, AE of materials, engineering structures and systems, including the processing of collected data and analytical techniques as well as experimental case studies.

  20. Acoustic biotelemetry from Slocum Gliders

    Science.gov (United States)

    Oliver, M. J.; Haulsee, D.; Breece, M.; Kohut, J. T.; Fox, D. A.; Wetherbee, B.; Cimino, M. A.

    2016-02-01

    The integration of biotelemetry and Slocum electric gliders presents new opportunities and challenges for interpreting the relationship between acoustically telemetered animals and the environment. Slocum gliders are able to stay in the field for extended periods (> 90 days) while collecting high-resolution data that can be used to reconstruct subsurface habitats. Here we present several case studies that compare integrated and externally mounted acoustic receiver technologies aboard Slocum gliders, compare detection efficiency between coastal arrays and Slocum gliders, investigate signal detectability in coastal habitats, and identify habitat associations of migrating species. Our studies leverage several ongoing tagging efforts, and would not be possible without a highly collaborative biotelemetry community. Slocum gliders are a robust technology that augments existing biotelemetry arrays and enable dynamic sampling of environments that extend beyond the feasibility of stationary arrays. The platforms are ideal for integrating biotelemetry into ocean observing and can provide ecologically relevant habitat associations that assist in the management of telemetered species.

  1. MR of acoustic neuromas

    International Nuclear Information System (INIS)

    Suzuki, Masayuki; Takashima, Tsutomu; Kadoya, Masumi; Takahashi, Shiroh; Miyayama, Shiroh; Taira, Sakae; Kashihara, Kengo; Yamashima, Tetsumori; Itoh, Haruhide

    1989-01-01

    In this report, the relationship of acoustic neuromas to the adjacent cranial nerves is discussed. On T 1 -weighted images, the trigeminal nerve was detected in all 13 cases. Mild to marked compression of these nerves by the tumors was observed in eight cases. The extent of compression did not always correspond to the clinical symptoms. In four cases with a maximum tumor diameter of 2 cm or less, the 7th and 8th cranial nerves were identified. There was no facial palsy in these patients. Two patients with a tumor diameter of more than 2 cm also had no facial palsy. All patients, including those with small tumors, complained of hearing loss and/or tinnitus. While MR imaging has some limitations, it is an effective imaging modality for showing the relationship between tumors and nerves. (author)

  2. An acoustic emission study of plastic deformation in polycrystalline aluminium

    Science.gov (United States)

    Bill, R. C.; Frederick, J. R.; Felbeck, D. K.

    1979-01-01

    Acoustic emission experiments were performed on polycrystalline and single crystal 99.99% aluminum while undergoing tensile deformation. It was found that acoustic emission counts as a function of grain size showed a maximum value at a particular grain size. Furthermore, the slip area associated with this particular grain size corresponded to the threshold level of detectability of single dislocation slip events. The rate of decline in acoustic emission activity as grain size is increased beyond the peak value suggests that grain boundary associated dislocation sources are giving rise to the bulk of the detected acoustic emissions.

  3. Acoustic emission monitoring during welding

    International Nuclear Information System (INIS)

    Prine, D.W.

    1980-01-01

    Weld repair is a major cost item, particularly in the fabrication of heavy section weldments such as pressure vessels. A heavy section repair can frequently leave the weld with worse problems than the original flaw. These problems may include damage to weld microstructure as well as added residual stress. The removal of flaws through in-process repair can minimize these problems and certainly, the removal of one or two passes and their replacement with automatic welding procedure is considerably cheaper than a heavy section post weld repair. The major barrier to application of in-process repair is the lack of an effective in-process inspection procedure. In-process monitoring of Acoustic Emission shows great promise for providing this much needed tool. The successful application of acoustic emission to in-process weld monitoring requires that advanced signal processing and pattern recognition techniques be applied if the flaw related acoustic emission is to be separated from the overwhelming amount of background noise present in welding. GARD, INC. has studied the problem of applying in-process acoustic emission monitoring to weld inspection for over 9 years and has empirically developed AE signal processing techniques which allow typical weld flaws to be detected, located, and characterized. This paper discusses these techniques and describes a recent successful field test of a microcomputer based AE weld monitor in a nuclear fabrication plant. (author)

  4. Tipping point analysis of ocean acoustic noise

    Science.gov (United States)

    Livina, Valerie N.; Brouwer, Albert; Harris, Peter; Wang, Lian; Sotirakopoulos, Kostas; Robinson, Stephen

    2018-02-01

    We apply tipping point analysis to a large record of ocean acoustic data to identify the main components of the acoustic dynamical system and study possible bifurcations and transitions of the system. The analysis is based on a statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the data using time-series techniques. We analyse long-term and seasonal trends, system states and acoustic fluctuations to reconstruct a one-dimensional stochastic equation to approximate the acoustic dynamical system. We apply potential analysis to acoustic fluctuations and detect several changes in the system states in the past 14 years. These are most likely caused by climatic phenomena. We analyse trends in sound pressure level within different frequency bands and hypothesize a possible anthropogenic impact on the acoustic environment. The tipping point analysis framework provides insight into the structure of the acoustic data and helps identify its dynamic phenomena, correctly reproducing the probability distribution and scaling properties (power-law correlations) of the time series.

  5. Tipping point analysis of ocean acoustic noise

    Directory of Open Access Journals (Sweden)

    V. N. Livina

    2018-02-01

    Full Text Available We apply tipping point analysis to a large record of ocean acoustic data to identify the main components of the acoustic dynamical system and study possible bifurcations and transitions of the system. The analysis is based on a statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the data using time-series techniques. We analyse long-term and seasonal trends, system states and acoustic fluctuations to reconstruct a one-dimensional stochastic equation to approximate the acoustic dynamical system. We apply potential analysis to acoustic fluctuations and detect several changes in the system states in the past 14 years. These are most likely caused by climatic phenomena. We analyse trends in sound pressure level within different frequency bands and hypothesize a possible anthropogenic impact on the acoustic environment. The tipping point analysis framework provides insight into the structure of the acoustic data and helps identify its dynamic phenomena, correctly reproducing the probability distribution and scaling properties (power-law correlations of the time series.

  6. Acoustic signal analysis in the creeping discharge

    International Nuclear Information System (INIS)

    Nakamiya, T; Sonoda, Y; Tsuda, R; Ebihara, K; Ikegami, T

    2008-01-01

    We have previously succeeded in measuring the acoustic signal due to the dielectric barrier discharge and discriminating the dominant frequency components of the acoustic signal. The dominant frequency components appear over 20kHz of acoustic signal by the dielectric barrier discharge. Recently surface discharge control technology has been focused from practical applications such as ozonizer, NO X reactors, light source or display. The fundamental experiments are carried to examine the creeping discharge using the acoustic signal. When the high voltage (6kV, f = 10kHz) is applied to the electrode, the discharge current flows and the acoustic sound is generated. The current, voltage waveforms of creeping discharge and the sound signal detected by the condenser microphone are stored in the digital memory scope. In this scheme, Continuous Wavelet Transform (CWT) is applied to discriminate the acoustic sound of the micro discharge and the dominant frequency components are studied. CWT results of sound signal show the frequency spectrum of wideband up to 100kHz. In addition, the energy distributions of acoustic signal are examined by CWT

  7. Imaging of Acoustic Waves in Sand

    Energy Technology Data Exchange (ETDEWEB)

    Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall

    2003-08-01

    There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.

  8. Real-time system for studies of the effects of acoustic feedback on animal vocalizations.

    Directory of Open Access Journals (Sweden)

    Mike eSkocik

    2013-01-01

    Full Text Available Studies of behavioral and neural responses to distorted auditory feedback can help shed light on the neural mechanisms of animal vocalizations. We describe an apparatus for generating real-time acoustic feedback. The system can very rapidly detect acoustic features in a song and output acoustic signals if the detected features match the desired acoustic template. The system uses spectrogram-based detection of acoustic elements. It is low-cost and can be programmed for a variety of behavioral experiments requiring acoustic feedback or neural stimulation. We use the system to study the effects of acoustic feedback on birds' vocalizations and demonstrate that such an acoustic feedback can cause both immediate and long-term changes to birds’ songs.

  9. Acoustic streaming in microchannels

    DEFF Research Database (Denmark)

    Tribler, Peter Muller

    This thesis presents studies of boundary-driven acoustic streaming in microfluidic channels, which is a steady flow of the fluid initiated by the interactions of an oscillating acoustic standing wave and the rigid walls of the microchannel. The studies present analysis of the acoustic resonance......, the acoustic streaming flow, and the forces on suspended microparticles. The work is motivated by the application of particle focusing by acoustic radiation forces in medical, environmental and food sciences. Here acoustic streaming is most often unwanted, because it limits the focusability of particles...... oscillating plates. Furthermore, under general thermodynamic conditions, we derive the time-dependent first- and second-order equations for the conservation of mass, momentum, and energy. The coupling from fluid equations to particle motion is achieved through the expressions for the streaming-induced drag...

  10. Vibro-acoustics

    CERN Document Server

    Nilsson, Anders

    2015-01-01

    This three-volume book gives a thorough and comprehensive presentation of vibration and acoustic theories. Different from traditional textbooks which typically deal with some aspects of either acoustic or vibration problems, it is unique of this book to combine those two correlated subjects together. Moreover, it provides fundamental analysis and mathematical descriptions for several crucial phenomena of Vibro-Acoustics which are quite useful in noise reduction, including how structures are excited, energy flows from an excitation point to a sound radiating surface, and finally how a structure radiates noise to a surrounding fluid. Many measurement results included in the text make the reading interesting and informative. Problems/questions are listed at the end of each chapter and the solutions are provided. This will help the readers to understand the topics of Vibro-Acoustics more deeply. The book should be of interest to anyone interested in sound and vibration, vehicle acoustics, ship acoustics and inter...

  11. Springer handbook of acoustics

    CERN Document Server

    2014-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and electronics. The Springer Handbook of Acoustics is also in his 2nd edition an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents. This new edition of the Handbook features over 11 revised and expanded chapters, new illustrations, and 2 new chapters covering microphone arrays  and acoustic emission.  Updated chapters contain the latest research and applications in, e.g. sound propagation in the atmosphere, nonlinear acoustics in fluids, building and concert hall acoustics, signal processing, psychoacoustics, computer music, animal bioacousics, sound intensity, modal acoustics as well as new chapters on microphone arrays an...

  12. Longitudinal bulk acoustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja

    2009-01-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise i...... in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.......A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise...

  13. [Acoustic information in snoring noises].

    Science.gov (United States)

    Janott, C; Schuller, B; Heiser, C

    2017-02-01

    More than one third of all people snore regularly. Snoring is a common accompaniment of obstructive sleep apnea (OSA) and is often disruptive for the bed partner. This work gives an overview of the history of and state of research on acoustic analysis of snoring for classification of OSA severity, detection of obstructive events, measurement of annoyance, and identification of the sound excitation location. Based on these objectives, searches were conducted in the literature databases PubMed and IEEE Xplore. Publications dealing with the respective objectives according to title and abstract were selected from the search results. A total of 48 publications concerning the above objectives were considered. The limiting factor of many studies is the small number of subjects upon which the analyses are based. Recent research findings show promising results, such that acoustic analysis may find a place in the framework of sleep diagnostics, thus supplementing the recognized standard methods.

  14. Deep Water Ocean Acoustics

    Science.gov (United States)

    2016-12-22

    analysis was conducted on the North Pacific Acoustics Laboratory Philippine Sea tests 2009 and 2010, both of which Dr. Heaney participated as a co-chief...obtained from the ambient noise field. In underwater acoustics , this travel time strongly depends on the depth and temperature and to a lesser extent...et al. 2012) and underwater volcanoes (Green at al. 2013). Guided wave propagation contributes to the limited acoustical attenuation by the SOFAR

  15. Shallow Water Acoustic Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports experimental research where high-frequency acoustic scattering and surface vibration measurements of fluid-loaded and non-fluid-loaded structures...

  16. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...

  17. Acoustic Technology Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — This laboratory contains an electro-magnetic worldwide data collection and field measurement capability in the area of acoustic technology. Outfitted by NASA Langley...

  18. Localized Acoustic Surface Modes

    KAUST Repository

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  19. Handbook of Engineering Acoustics

    CERN Document Server

    Möser, Michael

    2013-01-01

    This book examines the physical background of engineering acoustics, focusing on empirically obtained engineering experience as well as on measurement techniques and engineering methods for prognostics. Its goal is not only to describe the state of art of engineering acoustics but also to give practical help to engineers in order to solve acoustic problems. It deals with the origin, the transmission and the methods of the abating different kinds of air-borne and structure-borne sounds caused by various mechanisms – from traffic to machinery and flow-induced sound. In addition the modern aspects of room and building acoustics, as well as psychoacoustics and active noise control, are covered.

  20. Laboratory for Structural Acoustics

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports experimental research where acoustic radiation, scattering, and surface vibration measurements of fluid-loaded and non-fluid-loaded structures are...

  1. Acoustic emission during low temperature phase transformations in plutonium

    International Nuclear Information System (INIS)

    Khejpl, K.; Karpenter, S.

    1988-01-01

    To study the nature of phase transformations in plutonium and plutonium-gallium alloys (0.3 and 0.57% Ga) the measurement of acoustic emission is conducted. The presence of acoustic emission testifies to martensitic character of transformation, related to sharp local changes in the volume, which cause elastic waves. It is detected that during α reversible β transformations in non-alloyed plutonium acoustic emission is absent, and that testifies to nonmartensitic nature of the transformations. σ reversible α transformation in plutonium-gallium alloys is accompanied by the appearance of acoustic emission, i.e. it is of martensitic origin

  2. Detection of non-alcoholic steatohepatitis in patients with morbid obesity before bariatric surgery: preliminary evaluation with acoustic radiation force impulse imaging

    International Nuclear Information System (INIS)

    Guzman-Aroca, F.; Reus, M.; Dios Berna-Serna, Juan de; Frutos-Bernal, M.D.; Lujan-Mompean, J.A.; Parrilla, P.; Bas, A.

    2012-01-01

    To investigate the utility of acoustic radiation force impulse (ARFI) imaging, with the determination of shear wave velocity (SWV), to differentiate non-alcoholic fatty liver disease (NAFLD) from non-alcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery. Thirty-two patients with morbid obesity were evaluated with ARFI and conventional ultrasound before bariatric surgery. The ARFI and ultrasound results were compared with liver biopsy findings, which is the reference standard. The patients were classed according to their histological findings into three groups: group A, simple steatosis; group B, inflammation; and group C, fibrosis. The median SWV was 1.57 ± 0.79 m/s. Hepatic alterations were observed in the histopathological findings for all the patients in the study (100 %), with the results of the laboratory tests proving normal. Differences in SWV were also observed between groups A, B and C: 1.34 ± 0.90 m/s, 1.55 ± 0.79 m/s and 1.86 ± 0.75 m/s (P < 0.001), respectively. The Az for differentiating NAFLD from NASH or fibrosis was 0.899 (optimal cut-off value 1.3 m/s; sensitivity 85 %; specificity 83.3 %). The ARFI technique is a useful diagnostic tool for differentiating NAFLD from NASH in asymptomatic patients with morbid obesity. (orig.)

  3. Detection of non-alcoholic steatohepatitis in patients with morbid obesity before bariatric surgery: preliminary evaluation with acoustic radiation force impulse imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Aroca, F.; Reus, M.; Dios Berna-Serna, Juan de [Virgen de la Arrixaca University Hospital, Department of of Radiology, El Palmar, Murcia (Spain); Frutos-Bernal, M.D.; Lujan-Mompean, J.A.; Parrilla, P. [Virgen de la Arrixaca University Hospital, Department of Surgery, El Palmar, Murcia (Spain); Bas, A. [Virgen de la Arrixaca University Hospital, Department of Pathology, El Palmar, Murcia (Spain)

    2012-11-15

    To investigate the utility of acoustic radiation force impulse (ARFI) imaging, with the determination of shear wave velocity (SWV), to differentiate non-alcoholic fatty liver disease (NAFLD) from non-alcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery. Thirty-two patients with morbid obesity were evaluated with ARFI and conventional ultrasound before bariatric surgery. The ARFI and ultrasound results were compared with liver biopsy findings, which is the reference standard. The patients were classed according to their histological findings into three groups: group A, simple steatosis; group B, inflammation; and group C, fibrosis. The median SWV was 1.57 {+-} 0.79 m/s. Hepatic alterations were observed in the histopathological findings for all the patients in the study (100 %), with the results of the laboratory tests proving normal. Differences in SWV were also observed between groups A, B and C: 1.34 {+-} 0.90 m/s, 1.55 {+-} 0.79 m/s and 1.86 {+-} 0.75 m/s (P < 0.001), respectively. The Az for differentiating NAFLD from NASH or fibrosis was 0.899 (optimal cut-off value 1.3 m/s; sensitivity 85 %; specificity 83.3 %). The ARFI technique is a useful diagnostic tool for differentiating NAFLD from NASH in asymptomatic patients with morbid obesity. (orig.)

  4. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    Directory of Open Access Journals (Sweden)

    N. I. Polzikova

    2016-05-01

    Full Text Available We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW resonator (HBAR formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  5. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    Energy Technology Data Exchange (ETDEWEB)

    Polzikova, N. I., E-mail: polz@cplire.ru; Alekseev, S. G.; Pyataikin, I. I.; Kotelyanskii, I. M.; Luzanov, V. A.; Orlov, A. P. [Kotel’nikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Mokhovaya 11, building 7, Moscow, 125009 (Russian Federation)

    2016-05-15

    We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  6. High frequency acoustic on-chip integration for particle characterization and manipulation in microfluidics

    Science.gov (United States)

    Li, Sizhe; Carlier, Julien; Toubal, Malika; Liu, Huiqin; Campistron, Pierre; Callens, Dorothée; Nassar, Georges; Nongaillard, Bertrand; Guo, Shishang

    2017-10-01

    This letter presents a microfluidic device that integrates high frequency (650 MHz) bulk acoustic waves for the realization of particle handling on-chip. The core structure of the microfluidic chip is made up of a confocal lens, a vertical reflection wall, and a ZnO film transducer coupled with a silicon substrate for exciting acoustic beams. The excited acoustic waves propagate in bulk silicon and are then guided by a 45° silicon mirror into the suspensions in the microchannel; afterwards, the acoustic energy is focused on particles by the confocal lens and reflected by a reflection wall. Parts of the reflected acoustic energy backtrack into the transducer, and acoustic attenuation measurements are characterized for particle detection. Meanwhile, a strong acoustic streaming phenomenon can be seen around the reflection wall, which is used to implement particle manipulation. This platform opens a frontier for on-chip integration of high sensitivity acoustic characterization and localized acoustic manipulation in microfluidics.

  7. Air-coupled acoustic thermography for in-situ evaluation

    Science.gov (United States)

    Zalameda, Joseph N. (Inventor); Winfree, William P. (Inventor); Yost, William T. (Inventor)

    2010-01-01

    Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and/or repeatability, sound and/or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

  8. Study on Acoustic Catheter of Boiler Tube Leakage Monitoring Systems

    Science.gov (United States)

    Lv, Yongxing; Feng, Qiang

    Boiler tube leakage is the major reason of affecting the safe operation of the unit now, there are 3 methods of the "four tube" leakage detection: Traditional method, filtering method and acoustic spectrum analysis, acoustic spectrum analysis is the common method, but this method have low sensitivity and the sensor damage easily. Therewith, designed the special acoustic catheter with acoustic resonance cavity type, proved by experiments, the acoustic catheter with acoustic resonance cavity type can enhance leakage sound, can accurately extract leakage signals, has high sensitivity, and can avoid the effect of sensor by fire and hot-gas when the furnace is in positive pressure situation, reduce the installation and maintenance costs of the boiler tube leakage monitor system.

  9. Practical aspects of acoustic plastic pipe location

    Energy Technology Data Exchange (ETDEWEB)

    Huebler, J.E.; Campbell, B.K. [Institute of Gas Technology, Chicago, IL (United States); Ching, G.K. [Southern California Gas Co. (United States)

    1993-12-31

    Many gas distribution company operation and maintenance activities require precise knowledge of the location of buried plastic piping. Plastic pipe cannot be located if the tracer wire is gone or was never installed. Under sponsorship of the Southern California Gas Company, IGT successfully demonstrated an acoustic plastic pipe location technique and is developing the technique into a practical field instrument an acoustic signal is injected directly into the gas at a service. The acoustic signal travels in the gas in the pipes, not in the pipe wall. As the acoustic wave travels along the pipe, some of the sound radiates from the pipe through the soil to the surface of the ground. An array of sensors on the surface of the ground perpendicular to the pipe detects the acoustic signal, thereby locating the Pipe. Two different acoustic measurements are used. The first measurement locates the pipe to within {plus_minus} 3-ft. Then the second technique determines the location of the pipe to within {plus_minus} 6-in.

  10. Acoustic--nuclear permeability logging system

    International Nuclear Information System (INIS)

    Dowling, D.J.; Arnold, D.M.

    1978-01-01

    A down hole logging tool featuring a neutron generator, an acoustic disturbance generator, and a radiation detection system is described. An array of acoustic magnetostriction transducers is arranged about the target of a neutron accelerator. Two gamma ray sensors are separated from the accelerator target by shielding. According to the method of the invention, the underground fluid at the level of a formation is bombarded by neutrons which react with oxygen in the fluid to produce unstable nitrogen 16 particles according to the reaction 16 O(n,p) 16 N. Acoustic pulses are communicated to the fluid, and are incident on the boundary of the borehole at the formation. The resulting net flow of fluid across the boundary is determined from radiation detection measurements of the decaying 16 N particles in the fluid. A measure of the permeability of the formation is obtained from the determination of net fluid flow across the boundary

  11. Deep Water Ocean Acoustics

    Science.gov (United States)

    2015-07-17

    Ocean Acoustics 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER...paper and presented on global acoustic propagation (including on Europa, a small moon of Jupiter ) at the International Conference of Sound and

  12. Acoustic emission source modeling

    Czech Academy of Sciences Publication Activity Database

    Hora, Petr; Červená, Olga

    2010-01-01

    Roč. 4, č. 1 (2010), s. 25-36 ISSN 1802-680X R&D Projects: GA ČR GA101/09/1630 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission source * wave propagation * FEM Subject RIV: BI - Acoustics

  13. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

    Science.gov (United States)

    Clare, Elizabeth L; Holderied, Marc W

    2015-09-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an 'acoustic shadow' cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for 'acoustic camouflage' as an anti-predator defence mechanism.

  14. Computational Ocean Acoustics

    CERN Document Server

    Jensen, Finn B; Porter, Michael B; Schmidt, Henrik

    2011-01-01

    Since the mid-1970s, the computer has played an increasingly pivotal role in the field of ocean acoustics. Faster and less expensive than actual ocean experiments, and capable of accommodating the full complexity of the acoustic problem, numerical models are now standard research tools in ocean laboratories. The progress made in computational ocean acoustics over the last thirty years is summed up in this authoritative and innovatively illustrated new text. Written by some of the field's pioneers, all Fellows of the Acoustical Society of America, Computational Ocean Acoustics presents the latest numerical techniques for solving the wave equation in heterogeneous fluid–solid media. The authors discuss various computational schemes in detail, emphasizing the importance of theoretical foundations that lead directly to numerical implementations for real ocean environments. To further clarify the presentation, the fundamental propagation features of the techniques are illustrated in color. Computational Ocean A...

  15. Ocean acoustic reverberation tomography.

    Science.gov (United States)

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography.

  16. Acoustic Manifestations of Natural versus Triggered Lightning

    Science.gov (United States)

    Arechiga, R. O.; Johnson, J. B.; Edens, H. E.; Rison, W.; Thomas, R. J.; Eack, K.; Eastvedt, E. M.; Aulich, G. D.; Trueblood, J.

    2010-12-01

    Positive leaders are rarely detected by VHF lightning detection systems; positive leader channels are usually outlined only by recoil events. Positive cloud-to-ground (CG) channels are usually not mapped. The goal of this work is to study the types of thunder produced by natural versus triggered lightning and to assess which types of thunder signals have electromagnetic activity detected by the lightning mapping array (LMA). Towards this end we are investigating the lightning detection capabilities of acoustic techniques, and comparing them with the LMA. In a previous study we used array beam forming and time of flight information to locate acoustic sources associated with lightning. Even though there was some mismatch, generally LMA and acoustic techniques saw the same phenomena. To increase the database of acoustic data from lightning, we deployed a network of three infrasound arrays (30 m aperture) during the summer of 2010 (August 3 to present) in the Magdalena mountains of New Mexico, to monitor infrasound (below 20 Hz) and audio range sources due to natural and triggered lightning. The arrays were located at a range of distances (60 to 1400 m) surrounding the triggering site, called the Kiva, used by Langmuir Laboratory to launch rockets. We have continuous acoustic measurements of lightning data from July 20 to September 18 of 2009, and from August 3 to September 1 of 2010. So far, lightning activity around the Kiva was higher during the summer of 2009. We will present acoustic data from several interesting lightning flashes including a comparison between a natural and a triggered one.

  17. Acoustic Force Density Acting on Inhomogeneous Fluids in Acoustic Fields

    DEFF Research Database (Denmark)

    Karlsen, Jonas Tobias; Augustsson, Per; Bruus, Henrik

    2016-01-01

    We present a theory for the acoustic force density acting on inhomogeneous fluids in acoustic fields on time scales that are slow compared to the acoustic oscillation period. The acoustic force density depends on gradients in the density and compressibility of the fluid. For microfluidic systems...

  18. Parametric Room Acoustic workflows with real-time acoustic simulation

    DEFF Research Database (Denmark)

    Parigi, Dario

    2017-01-01

    The paper investigates and assesses the opportunities that real-time acoustic simulation offer to engage in parametric acoustics workflow and to influence architectural designs from early design stages......The paper investigates and assesses the opportunities that real-time acoustic simulation offer to engage in parametric acoustics workflow and to influence architectural designs from early design stages...

  19. Broadband unidirectional acoustic cloak based on phase gradient metasurfaces with two flat acoustic lenses

    Science.gov (United States)

    Wang, Xiao-Peng; Wan, Le-Le; Chen, Tian-Ning; Song, Ai-Ling; Wang, Fang

    2016-07-01

    Narrow bandwidth and bulky configuration are the main obstacles for the realization and application of invisible cloaks. In this paper, we present an effective method to achieve broadband and thin acoustic cloak by using an acoustic metasurface (AMS). In order to realize this cloak, we use slitted unit cells to design the AMS due to the advantage of less energy loss, broad operation bandwidth, and subwavelength thickness. According to the hyperboloidal phase profile along the AMS, the incident plane waves can be focused at a designed focal spot by the flat lens. Furthermore, broadband acoustic cloak is obtained by combining two identical flat lenses. The incident plane waves are focused at the center point in between of the two lenses by passing through one lens, and then recovered by passing through the other one. However, they cannot reach the cloaked regions in between of the two lenses. The simulation results can verify the non-detectability effect of the acoustic cloak. Our study results provide an available and simple approach to experimentally achieve the acoustic cloak, which can be used in acoustic non-detectability for large objects.

  20. Acoustic Thermometry of Ocean Climate: Marine Mammal Issues

    National Research Council Canada - National Science Library

    Buck, Eugene H

    1995-01-01

    .... Acoustic thermometry can detect changes in ocean temperature by receiving low-frequency sounds transmitted across an ocean basin because the speed of sound is proportional to water temperature...

  1. Ladar-Acoustic Fused Sensor for Area Denial Application

    National Research Council Canada - National Science Library

    Kisatsky, Paul

    2000-01-01

    .... ARDEC is currently investigating short range, low cost, ladar-acoustic hybrid sensors, which would be capable of detecting, classifying, tracking, and selecting the optimal firing path to vehicular...

  2. Acoustic monitoring of terrorist intrusion in a drinking water network

    NARCIS (Netherlands)

    Quesson, B.A.J.; Sheldon-Robert, M.K.; Vloerbergh, I.N.; Vreeburg, J.H.G.

    2009-01-01

    In collaboration with Kiwa Water Research, TNO (Netherlands Organisation for Applied Scientific Research) has investigated the possibilities to detect and classify aberrant sounds in water networks, using acoustic sensors. Amongst the sources of such sounds are pumps, drills, mechanical impacts,

  3. Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants.

    Science.gov (United States)

    Sayago, Isabel; Matatagui, Daniel; Fernández, María Jesús; Fontecha, José Luis; Jurewicz, Izabela; Garriga, Rosa; Muñoz, Edgar

    2016-02-01

    A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Acoustic detection of Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) and Oryctes elegans (Coleoptera: Scarabaeidae) in Phoenix dactylifera (Arecales: Arecacae) trees and offshoots in Saudi Arabian orchards

    Science.gov (United States)

    Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) larvae are cryptic, internal-tissue feeding pests of palm trees that are difficult to detect until after they have caused severe economic damage; consequently, infestations may remain undetected until they are widespread in an orchard....

  5. Acoustic well cleaner

    Science.gov (United States)

    Maki, Jr., Voldi E.; Sharma, Mukul M.

    1997-01-21

    A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.

  6. Estimating propagation velocity through a surface acoustic wave sensor

    Science.gov (United States)

    Xu, Wenyuan; Huizinga, John S.

    2010-03-16

    Techniques are described for estimating the propagation velocity through a surface acoustic wave sensor. In particular, techniques which measure and exploit a proper segment of phase frequency response of the surface acoustic wave sensor are described for use as a basis of bacterial detection by the sensor. As described, use of velocity estimation based on a proper segment of phase frequency response has advantages over conventional techniques that use phase shift as the basis for detection.

  7. Immersed acoustical transducers and their potential uses in LMFBR

    International Nuclear Information System (INIS)

    Argous, J.P.; Brunet, M.; Baron, J.; Lhuillier, C.; Segui, J.L.

    1980-04-01

    Six years satisfactory operation in PHENIX has proved the reliability and effectivness of under-sodium viewing (VISUS) and Acoustic Detection. This fact has been strong incentive to maintain, on the future LMFBR the visus as well as the Acoustic Detection functions. These two functions are performed on SUPER PHENIX, by two sets of distinct systems using the well-known solution. Taking into account of recent improvements in sodium immersible acoustic transducers technology, CEA decided to undertake the development of a multi-functions instrument. This paper gives an outline of this new concept, which should be able to reduce the cost and the complexity of core instrumentation

  8. Acoustic emission experiments for PHWR technology development

    International Nuclear Information System (INIS)

    Pellionisz, P.; Jha, S.K.; Goswami, G.L.

    1992-06-01

    An Indian-Hungarian joint research project has been started with the aim of applying acoustic emission testing to solve specific problems of nuclear power plants. Acoustic emission measurement and analyzing instrumentation and software have been provided by the Hungarian side, while the measurements have been performed at the Bhabha Atomic Research Centre (BARC), India. The first task of the project was to check the capability of the method for leakage detection and shuttle movement monitoring of Pressurized Heavy Water Reactors (PHWR), and for monitoring manufacturing processes as laser welding. The preliminary measurements and results are presented. (R.P.) 15 refs.; 11 figs.; 3 tabs

  9. Seismic resonances of acoustic cavities

    Science.gov (United States)

    Schneider, F. M.; Esterhazy, S.; Perugia, I.; Bokelmann, G.

    2016-12-01

    The goal of an On-Site Inspection (OSI) is to clarify at a possible testsite whether a member state of the Comprehensive nuclear Test Ban Treaty (CTBT)has violated its rules by conducting a underground nuclear test. Compared toatmospheric and underwater tests underground nuclear explosions are the mostdifficult to detect.One primary structural target for the field team during an OSI is the detectionof an underground cavity, created by underground nuclear explosions. Theapplication of seismic-resonances of the cavity for its detection has beenproposed in the CTBT by mentioning "resonance seismometry" as possibletechnique during OSIs. We modeled the interaction of a seismic wave-field withan underground cavity by a sphere filled with an acoustic medium surrounded byan elastic full space. For this setting the solution of the seismic wave-fieldcan be computed analytically. Using this approach the appearance of acousticresonances can be predicted in the theoretical calculations. Resonance peaksappear in the spectrum derived for the elastic domain surrounding the acousticcavity, which scale in width with the density of the acoustic medium. For lowdensities in the acoustic medium as for an gas-filled cavity, the spectralpeaks become very narrow and therefore hard to resolve. The resonancefrequencies, however can be correlated to the discrete set of eigenmodes of theacoustic cavity and can thus be predicted if the dimension of the cavity isknown. Origin of the resonance peaks are internal reverberations of wavescoupling in the acoustic domain and causing an echoing signal that couples outto the elastic domain again. In the gas-filled case the amplitudes in timedomain are very low.Beside theoretical considerations we seek to find real data examples fromsimilar settings. As example we analyze a 3D active seismic data set fromFelsőpetény, Hungary that has been conducted between 2012 and 2014 on behalf ofthe CTBTO. In the subsurface of this area a former clay mine is

  10. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Connections Overview Find a Meeting Host a Meeting Volunteer Become a Volunteer Opportunities Support Overview Patient Events ... ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree ...

  11. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... with AN Healthcare Providers Acoustic Neuroma Association Donate Now Newly Diagnosed What is AN? Request a Patient ... Volunteer About ANA Get Info Shop ANA Donate Now DONATE Ways to Give Legacy Society Team ANA © ...

  12. Acoustics Noise Test Cell

    Data.gov (United States)

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  13. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Choosing a healthcare provider Request a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side effects Question To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a ...

  14. Acoustic imaging system

    Science.gov (United States)

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  15. Acoustic Igniter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  16. Cryogenic Acoustic Suppression Testing

    Data.gov (United States)

    National Aeronautics and Space Administration — A proof-of-concept method utilizing a cryogenic fluid for acoustic suppression in rocket engine testing environments will be demonstrated. It is hypothesized that...

  17. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree Parkway Suite 108 ... About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video English English ...

  18. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree ... info@ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational ...

  19. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video English English Arabic Catalan Chinese ( ...

  20. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Info Booklets Research Back ANA Survey/Registry AN Research ... About Back Learn more about ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic ...

  1. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side effects ... To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a healthcare provider Request a patient kit ...

  2. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Back Learn more about ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic ... 205-8211 info@ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home ...

  3. Department of Cybernetic Acoustics

    Science.gov (United States)

    The development of the theory, instrumentation and applications of methods and systems for the measurement, analysis, processing and synthesis of acoustic signals within the audio frequency range, particularly of the speech signal and the vibro-acoustic signal emitted by technical and industrial equipments treated as noise and vibration sources was discussed. The research work, both theoretical and experimental, aims at applications in various branches of science, and medicine, such as: acoustical diagnostics and phoniatric rehabilitation of pathological and postoperative states of the speech organ; bilateral ""man-machine'' speech communication based on the analysis, recognition and synthesis of the speech signal; vibro-acoustical diagnostics and continuous monitoring of the state of machines, technical equipments and technological processes.

  4. Autonomous Acoustic Receiver System

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Collects underwater acoustic data and oceanographic data. Data are recorded onboard an ocean buoy and can be telemetered to a remote ship or shore station...

  5. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Learn more about ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma ... 8211 info@ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn ...

  6. Acoustic MIMO signal processing

    CERN Document Server

    Huang, Yiteng; Chen, Jingdong

    2006-01-01

    A timely and important book addressing a variety of acoustic signal processing problems under multiple-input multiple-output (MIMO) scenarios. It uniquely investigates these problems within a unified framework offering a novel and penetrating analysis.

  7. Thermal Acoustic Fatigue Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — The Thermal Acoustic Fatigue Apparatus (TAFA) is a progressive wave tube test facility that is used to test structures for dynamic response and sonic fatigue due to...

  8. Principles of musical acoustics

    CERN Document Server

    Hartmann, William M

    2013-01-01

    Principles of Musical Acoustics focuses on the basic principles in the science and technology of music. Musical examples and specific musical instruments demonstrate the principles. The book begins with a study of vibrations and waves, in that order. These topics constitute the basic physical properties of sound, one of two pillars supporting the science of musical acoustics. The second pillar is the human element, the physiological and psychological aspects of acoustical science. The perceptual topics include loudness, pitch, tone color, and localization of sound. With these two pillars in place, it is possible to go in a variety of directions. The book treats in turn, the topics of room acoustics, audio both analog and digital, broadcasting, and speech. It ends with chapters on the traditional musical instruments, organized by family. The mathematical level of this book assumes that the reader is familiar with elementary algebra. Trigonometric functions, logarithms and powers also appear in the book, but co...

  9. Acoustic ambient noise recorder

    Digital Repository Service at National Institute of Oceanography (India)

    Saran, A.K.; Navelkar, G.S.; Almeida, A.M.; More, S.R.; Chodankar, P.V.; Murty, C.S.

    with a robust outfit that can withstand high pressures and chemically corrosion resistant materials. Keeping these considerations in view, a CMOS micro-controller-based marine acoustic ambient noise recorder has been developed with a real time clock...

  10. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Request a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side ... Question To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a healthcare provider Request a patient ...

  11. Acoustic Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  12. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree Parkway ... ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video ...

  13. Proceedings of the specialists' meeting on acoustic/ultrasonic detection of in sodium water leaks on steam generators, held in Aix-en-Provence, France, 1-3 October 1990

    International Nuclear Information System (INIS)

    Girard, J.P.

    1990-10-01

    23 officially nominated persons and 8 observers from 7 countries operating fast breeder reactors in the world, Mr. Arkhipov, IAEA Scientific Secretary of IWGFR and Mr. Cambillard, French member of IWGFR attended the specialists meeting. 25 papers were presented in the national status session and in 3 technical sessions devoted to methods, theoretical approach and real steam generator experience. A separate abstract was prepared for each of these papers. Since the last meetings in Dimitrovgrad and Petten it is clear that acoustic/ultrasonic monitoring of in-sodium water leaks is now considered by all countries as a major topic for commercial fast reactor steam generator unit protection. At this time the detection of leakage events is thought to be possible in the leak range from 1 to about 100 g/s in a time period of a few seconds to a few tens of seconds. Future work should aim at a more precise definition of the attainable limits, taking into account the particular requirements of actual plant design. Refs, figs and tabs

  14. Resonant surface acoustic wave chemical detector

    Science.gov (United States)

    Brocato, Robert W.; Brocato, Terisse; Stotts, Larry G.

    2017-08-08

    Apparatus for chemical detection includes a pair of interdigitated transducers (IDTs) formed on a piezoelectric substrate. The apparatus includes a layer of adsorptive material deposited on a surface of the piezoelectric substrate between the IDTs, where each IDT is conformed, and is dimensioned in relation to an operating frequency and an acoustic velocity of the piezoelectric substrate, so as to function as a single-phase uni-directional transducer (SPUDT) at the operating frequency. Additionally, the apparatus includes the pair of IDTs is spaced apart along a propagation axis and mutually aligned relative to said propagation axis so as to define an acoustic cavity that is resonant to surface acoustic waves (SAWs) at the operating frequency, where a distance between each IDT of the pair of IDTs ranges from 100 wavelength of the operating frequency to 400 wavelength of the operating frequency.

  15. Inverse Doppler Effects in Broadband Acoustic Metamaterials.

    Science.gov (United States)

    Zhai, S L; Zhao, X P; Liu, S; Shen, F L; Li, L L; Luo, C R

    2016-08-31

    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with 'flute-like' acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  16. Acoustic comfort in eating establishments

    DEFF Research Database (Denmark)

    Svensson, David; Jeong, Cheol-Ho; Brunskog, Jonas

    2014-01-01

    The subjective concept of acoustic comfort in eating establishments has been investigated in this study. The goal was to develop a predictive model for the acoustic comfort, by means of simple objective parameters, while also examining which other subjective acoustic parameters could help explain...... the feeling of acoustic comfort. Through several layers of anal ysis, acoustic comfort was found to be rather complex, and could not be explained entirely by common subjective parameters such as annoyance, intelligibility or privacy. A predictive model for the mean acoustic comfort for an eating establishment...

  17. Application of Acoustic Techniques in Thermal Power Plants

    Directory of Open Access Journals (Sweden)

    T. K. Sai

    2017-03-01

    Full Text Available In the power plant, for over two decades, use of acoustic techniques were limited only to detect steam leaks in the Boiler. Even this application has certain limitations like interfering background noises, sound wave attenuations, and inaccessibility of desired sensor locations. For these reasons a proper specialized technique, generally unique to a given application, be employed to ensure optimum sensitivity. This paper presents an innovative approach towards use of acoustic techniques in a 500 MW thermal power plant. The application areas include clinker /sagging detection, steam leak detection and combustion optimization. In the steam leak detection and combustion optimization, the present day limitations are overcome. The use of acoustic technology to detect clinker formation is a new concept. All the three applications are designed and implemented in a 500 MW power plant.

  18. Acoustic analysis of explosions in high noise environment

    Science.gov (United States)

    Man, Hong; Desai, Sachi

    2008-04-01

    Explosion detection and recognition is a critical capability to provide situational awareness to the war-fighters in battlefield. Acoustic sensors are frequently deployed to detect such events and to trigger more expensive sensing/sensor modalities (i.e. radar, laser spectroscope, IR etc.). Acoustic analysis of explosions has been intensively studied to reliably discriminate mortars, artillery, round variations, and type of blast (i.e. chemical/biological or high-explosive). One of the major challenges is high level of noise, which may include non-coherent noise generated from the environmental background and coherent noise induced by possible mobile acoustic sensor platform. In this work, we introduce a new acoustic scene analysis method to effectively enhance explosion classification reliability and reduce the false alarm rate at low SNR and with high coherent noise. The proposed method is based on acoustic signature modeling using Hidden Markov Models (HMMs). Special frequency domain acoustic features characterizing explosions as well as coherent noise are extracted from each signal segment, which forms an observation vector for HMM training and test. Classification is based on a unique model similarity measure between the HMM estimated from the test observations and the trained HMMs. Experimental tests are based on the acoustic explosion dataset from US ARMY ARDEC, and experimental results have demonstrated the effectiveness of the proposed method.

  19. Acoustic resonance spectroscopy intrinsic seals

    International Nuclear Information System (INIS)

    Olinger, C.T.; Burr, T.; Vnuk, D.R.

    1994-01-01

    We have begun to quantify the ability of acoustic resonance spectroscopy (ARS) to detect the removal and replacement of the lid of a simulated special nuclear materials drum. Conceptually, the acoustic spectrum of a container establishcs a baseline fingerprint, which we refer to as an intrinsic seal, for the container. Simply removing and replacing the lid changes some of the resonant frequencies because it is impossible to exactly duplicate all of the stress patterns between the lid and container. Preliminary qualitative results suggested that the ARS intrinsic seal could discriminate between cases where a lid has or has not been removed. The present work is directed at quantifying the utility of the ARS intrinsic seal technique, including the technique's sensitivity to ''nuisance'' effects, such as temperature swings, movement of the container, and placement of the transducers. These early quantitative tests support the potential of the ARS intrinsic seal application, but also reveal a possible sensitivity to nuisance effects that could limit environments or conditions under which the technique is effective

  20. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  1. Practical acoustic emission testing

    CERN Document Server

    2016-01-01

    This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.

  2. Sea Turtle Acoustic Telemetry Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Acoustic transmitters attached to sea turtles captured in various fishing gear enable the animals to be passively tracked. Acoustic receivers set up in an array...

  3. Advanced Active Acoustics Lab (AAAL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Active Acoustics Lab (AAAL) is a state-of-the-art Undersea Warfare (USW) acoustic data analysis facility capable of both active and passive underwater...

  4. Lightning Location Using Acoustic Signals

    Science.gov (United States)

    Badillo, E.; Arechiga, R. O.; Thomas, R. J.

    2013-05-01

    In the summer of 2011 and 2012 a network of acoustic arrays was deployed in the Magdalena mountains of central New Mexico to locate lightning flashes. A Times-Correlation (TC) ray-tracing-based-technique was developed in order to obtain the location of lightning flashes near the network. The TC technique, locates acoustic sources from lightning. It was developed to complement the lightning location of RF sources detected by the Lightning Mapping Array (LMA) developed at Langmuir Laboratory, in New Mexico Tech. The network consisted of four arrays with four microphones each. The microphones on each array were placed in a triangular configuration with one of the microphones in the center of the array. The distance between the central microphone and the rest of them was about 30 m. The distance between centers of the arrays ranged from 500 m to 1500 m. The TC technique uses times of arrival (TOA) of acoustic waves to trace back the location of thunder sources. In order to obtain the times of arrival, the signals were filtered in a frequency band of 2 to 20 hertz and cross-correlated. Once the times of arrival were obtained, the Levenberg-Marquardt algorithm was applied to locate the spatial coordinates (x,y, and z) of thunder sources. Two techniques were used and contrasted to compute the accuracy of the TC method: Nearest-Neighbors (NN), between acoustic and LMA located sources, and standard deviation from the curvature matrix of the system as a measure of dispersion of the results. For the best case scenario, a triggered lightning event, the TC method applied with four microphones, located sources with a median error of 152 m and 142.9 m using nearest-neighbors and standard deviation respectively.; Results of the TC method in the lightning event recorded at 18:47:35 UTC, August 6, 2012. Black dots represent the results computed. Light color dots represent the LMA data for the same event. The results were obtained with the MGTM station (four channels). This figure

  5. Four cases of acoustic neurinoma presenting with symmetrical hearing

    International Nuclear Information System (INIS)

    Matsuyoshi, Hidetake; Minoda, Ryousei; Yumoto, Eiji

    2008-01-01

    There were 37 cases of acoustic neurinoma, diagnosed at Kumamoto University hospital from 2002 to 2006. We reported four cases of acoustic neurinoma presenting with symmetrical hearing. As for chief complaint at the initial examination, three patient had cochlear or vestibular symptoms of ear fullness, vertigo or hearing loss, one patient had only headache. All cases displayed nystagmus such as paralysis-related nystagmus or upbeat nystagmus, in addition, displayed canal paresis in the affected ear. Caloric test and nystagmus showed valuable findings for detecting acoustic neurinomas presenting with symmetrical hearing. (author)

  6. Interpreting underwater acoustic images of the upper ocean boundary layer

    International Nuclear Information System (INIS)

    Ulloa, Marco J

    2007-01-01

    A challenging task in physical studies of the upper ocean using underwater sound is the interpretation of high-resolution acoustic images. This paper covers a number of basic concepts necessary for undergraduate and postgraduate students to identify the most distinctive features of the images, providing a link with the acoustic signatures of physical processes occurring simultaneously beneath the surface of the sea. Sonars are so sensitive that they detected a new acoustic signature at the breaking of surface gravity waves in deep water, which resembles oblique motion-like vortices

  7. Acoustic integrated extinction

    OpenAIRE

    Norris, Andrew N.

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122, 3206–3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we der...

  8. Room Acoustical Fields

    CERN Document Server

    Mechel, Fridolin

    2013-01-01

    This book presents the theory of room acoustical fields and revises the Mirror Source Methods for practical computational use, emphasizing the wave character of acoustical fields.  The presented higher methods include the concepts of “Mirror Point Sources” and “Corner sources which allow for an excellent approximation of complex room geometries and even equipped rooms. In contrast to classical description, this book extends the theory of sound fields describing them by their complex sound pressure and the particle velocity. This approach enables accurate descriptions of interference and absorption phenomena.

  9. Carbon Nanotube Underwater Acoustic Thermophone

    Science.gov (United States)

    2016-09-23

    Attorney Docket No. 300009 1 of 8 A CARBON NANOTUBE UNDERWATER ACOUSTIC THERMOPHONE STATEMENT OF GOVERNMENT INTEREST [0001] The...the Invention [0003] The present invention is an acoustically transparent carbon nanotube thermophone. (2) Description of the Prior Art [0004...amplitude of the resulting sound waves. [0006] Recently, there has been development of underwater acoustic carbon nanotube (CNT) yarn sheets capable

  10. Failure site location by acoustic emission for composites reliability assurance

    OpenAIRE

    Gish, Donald A.

    1995-01-01

    The failure of fiber filaments in a composite subjected to load produces a stress wave which can be detected using acoustic emission techniques. The spatial clustering of multiple fiber failure sites is known to cause catastrophic failure of the macro composite. Acoustic emission can be used to determine locations of these flaws, providing a useful tool for reliability assurance of composite structures. This investigation establishes the necessary foundation by categorically quantifying the m...

  11. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    OpenAIRE

    Felis, Ivan; Mart?nez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. ...

  12. Signal Processing of Underwater Acoustic Waves

    Science.gov (United States)

    1969-11-01

    goes through a surface dipole distribution.. Show that when the work is expressed as a Stieltjes integral, this difficulty is avoided. 4.6 A stochastic...and Sons, Inc., New York, 1953 Duflos, J.: Etude des Effects de 1’Echantillonnage en Detection des Signaux Foibles, l’Onde Electrique , Paris, No. 443...M., and R. J. Thompson-’ Directivity Study of the Noise Field in the Ocean, Employing a Correlative Dipole , J. Acoust. Soc. Am. 36, pp. 1788-1794

  13. how acoustic schwannomas?

    African Journals Online (AJOL)

    chemistry In the diagnosis of brain tumours and, furthermore, shows that acoustic schwannoma must be considered In the appropriate clinical setting, even in a group previously regarded as low-risk. S Atr Med J 1990; 78: 11-14. Studies from various parts of the world on the relative. freqIJency of primary intracranial tumours ...

  14. Nonlinear acoustic tomography

    International Nuclear Information System (INIS)

    Monk, P.

    1993-01-01

    The use of acoustic waves as probes to determine otherwise inaccessible properties of a medium is extremely widespread. Applications include sonar, medical imaging and non-destructive testing. Despite the importance of the applications, there is as yet no acceptable method for solving the full non-linear problem at resonance frequencies (frequencies at which the size of the features under investigations are approximately the wavelength of the incident acoustic field). The medical imaging problem, which consists in trying to determine the sound speed, density and absorption properties of a bounded inhomogeneous medium from scattered acoustic waves is the motivaiton for the investigation described in this paper. We shall present a solution technique for a standard model inverse acoustic scattering problem which consists of reconstructing the refractive index of an inhomogeneity from given far field data (far field data is essentially the measured scattered field at considerable distance from the inhomogeneity). This model inverse problem simplifies the inhomogeneity by neglecting density and absorption but includes two important features of the real problem: nonlinearity and illposedness. Furthermore the method we present can easily by extended to more general problems

  15. Acoustic emission from beryllium

    International Nuclear Information System (INIS)

    Heiple, C.R.; Adams, R.O.

    1976-01-01

    The acoustic emission from both powder and ingot source beryllium has been measured as a function of strain and prior heat treatment. Most measurements were made during tensile deformation, but a limited number of compression tests have also been performed. The acoustic emission observed was of the burst type, with little or no contribution from continuous type emission. The emission was characterized by the variation of burst rate and average energy per burst as a function of strain. The tensile behavior was qualitatively similar for all the materials tested. Burst rate maxima centered roughly at 0.1 percent and 1.0 percent plastic strain were observed. The magnitude but not the strain at the low strain burst rate peak was very sensitive to prior thermal treatment, while the higher strain burst rate peak was insensitive to prior heat treatment. An energy per burst maximum was observed at 0.2 percent plastic strain, the magnitude of which was moderately sensitive to heat treatment. The Kaiser effect is observed in the material studied. Emission during compression was similar to that observed in tension. The acoustic emission observed is attributed to dislocation motion, as proposed by James and Carpenter for LiF, NaCl, and Zn. Metallographic studies of the beryllium at various strains have ruled out microcracking and twin formation as major contributors to the acoustic emission

  16. Acoustic force spectroscopy

    NARCIS (Netherlands)

    Sitters, G.; Kamsma, D.; Thalhammer, G.; Ritsch-Marte, M.; Peterman, E.J.G.; Wuite, G.J.L.

    2015-01-01

    Force spectroscopy has become an indispensable tool to unravel the structural and mechanochemical properties of biomolecules. Here we extend the force spectroscopy toolbox with an acoustic manipulation device that can exert forces from subpiconewtons to hundreds of piconewtons on thousands of

  17. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... 770-205-8211 info@ANAUSA.org ANAwareness Week 2018 – read more Click to learn more... LOGIN CALENDAR ... DONATE Ways to Give Legacy Society Team ANA © 2018 Acoustic Neuroma Association • 600 Peachtree Parkway • Suite 108 • ...

  18. Diagnosing Acoustic Neuroma

    Science.gov (United States)

    ... triggered by a patient’s symptoms. The most common presenting feature of acoustic neuromas, occurring in 90% of patients, is unilateral hearing loss. When "pure tone audiometry" is used, the most common finding is high frequency hearing loss. The hearing loss ...

  19. Select Internet Resources on Acoustics

    Directory of Open Access Journals (Sweden)

    Angela R. Davis

    2016-12-01

    Full Text Available Merriam-Webster (2016 defines acoustics as, “a science that deals with the production, control, transmission, reception, and effects of sounds.” According to Rossing (2014, the study of acoustics began in ancient Greece with Pythagoras’ study of vibrating strings on musical instruments. Since those early beginnings, famous scientists including Rayleigh, Alexander Graham Bell, and Thomas Edison, have helped expand the field of acoustics to include architectural, physical, engineering, structural, underwater, physiological and psychological, musical acoustics, and speech. Acoustics is a highly interdisciplinary field and researchers may need resources from physics, medicine, and engineering to understand all aspects of their research.

  20. Acoustic emission: technical review for PWR applications

    International Nuclear Information System (INIS)

    Bentley, P.G.

    1981-07-01

    Acoustic emission has been studied since the early 1960's, particularly with a view to periodic or continuous monitoring of steel pressure vessels. In the years 1970-75 it was realised that ductile steels, used in nuclear vessels, give small amplitude signals which are barely detectable by available instruments. The technique for application in periodic or continuous monitoring and also as applied to leak detection and weld fabrication monitoring is reviewed. It is concluded that manufacturing defects may be detectable during pre-service hydrotest, but that there is insufficient evidence on which to base an estimate of detection probability. In-service hydrotest or continuous monitoring is unlikely to detect growing cracks because of the quiet nature of the material and the noisy reactor background. Both leak detection and fabrication weld monitoring show some promise of successful application in the future. (author)

  1. Controlling sound with acoustic metamaterials

    DEFF Research Database (Denmark)

    Cummer, Steven A. ; Christensen, Johan; Alù, Andrea

    2016-01-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales....... The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create......-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview...

  2. An Overview of Acoustic Detection Analysis.

    Science.gov (United States)

    1983-01-01

    PL(r) and NL are typically determined from publica - tions that give geographic and seasonal values for these parameters. The left-hand side of the...In Seguridad hence) 14 p., Oct 1980, AD A092 733 wiorthwstern University, Evanston, IL PP 297 - Classified PP 3o9 Bowes, Marianne, Brchling, Frank P

  3. Results of acoustic measurements with an electric boiling generator at KNK II

    International Nuclear Information System (INIS)

    Aberle, J.

    1987-08-01

    With regard to an integral core surveillance in sodium-cooled breeder reactors acoustic measurement techniques are under development. To determine experimentally the acoustic transfer function of a reactor core and to demonstrate the detectability of local sodium boiling, experiments with a so-called Boiling Generator were carried out in the KNK II reactor. The main part of this Boiling Generator was an electrically heated pin bundle which was equipped with a local blockage to obtain cooling disturbances. In this report the results of the acoustic measurements carried out with the Boiling Generator are presented. Main topic of the evaluation is the determination of the acoustic transfer function between the core and the upper sodium plenum. The signal conditioning necessary prior to this investigation is also explained. Great effort was required to suppress electrical disturbances which superimposed the acoustic signals and could not be eliminated by the hardware during the experiments. Finally, the detectability of local boiling using acoustic measurements is considered

  4. Passive acoustic monitoring of human physiology during activity indicates health and performance of soldiers and firefighters

    Science.gov (United States)

    Scanlon, Michael V.

    2003-04-01

    The Army Research Laboratory has developed a unique gel-coupled acoustic physiological monitoring sensor that has acoustic impedance properties similar to the skin. This facilitates the transmission of body sounds into the sensor pad, yet significantly repels ambient airborne noises due to an impedance mismatch. The sensor's sensitivity and bandwidth produce excellent signatures for detection and spectral analysis of diverse physiological events. Acoustic signal processing detects heartbeats, breaths, wheezes, coughs, blood pressure, activity, motion, and voice for communication and automatic speech recognition. The health and performance of soldiers, firefighters, and other first responders in strenuous and hazardous environments can be continuously and remotely monitored with body-worn acoustic sensors. Comfortable acoustic sensors can be in a helmet or in a strap around the neck, chest, and wrist. Noise-canceling sensor arrays help remove out-of-phase motion noise and enhance covariant physiology by using two acoustic sensors on the front sides of the neck and two additional acoustic sensors on each wrist. Pulse wave transit time between neck and wrist acoustic sensors will indicate systolic blood pressure. Larger torso-sized arrays can be used to acoustically inspect the lungs and heart, or built into beds for sleep monitoring. Acoustics is an excellent input for sensor fusion.

  5. Flat acoustic lens by acoustic grating with curled slits

    KAUST Repository

    Peng, Pai

    2014-10-01

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance.

  6. Acoustic Resonance Characteristics of Rock and Concrete Containing Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Seiji [Univ. of California, Berkeley, CA (United States)

    1998-08-01

    In recent years, acoustic resonance has drawn great attention as a quantitative tool for characterizing properties of materials and detecting defects in both engineering and geological materials. In quasi-brittle materials such as rock and concrete, inherent fractures have a significant influence on their mechanical and hydraulic properties. Most of these fractures are partially open, providing internal boundaries that are visible to propagating seismic waves. Acoustic resonance occurs as a result of constructive and destructive interferences of propagating waves. Therefore the geometrical and mechanical properties of the fracture are also interrogated by the acoustic resonance characteristics of materials. The objective of this dissertation is to understand the acoustic resonance characteristics of fractured rock and concrete.

  7. An acoustic prion assay

    Directory of Open Access Journals (Sweden)

    Gordon Hayward

    2016-12-01

    Full Text Available An acoustic prion assay has been demonstrated for sheep brain samples. Only five false positives and no false negatives were observed in a test of 45 positive and 45 negative samples. The acoustic prion sensor was constructed using a thickness shear mode quartz resonator coated with a covalently bound recombinant prion protein. The characteristic indicator of a scrapie infected sheep brain sample was an observed shoulder in the frequency decrease in response to a sample.The response of the sensor aligns with a conformational shift in the surface protein and with the propagation mechanism of the disease. This alignment is evident in the response timing and shape, dependence on concentration, cross species behaviour and impact of blood plasma. This alignment is far from sufficient to prove the mechanism of the sensor but it does offer the possibility of a rapid and inexpensive additional tool to explore prion disease. Keywords: Prions, Thickness shear mode quartz sensor

  8. Suppression through acoustics

    Science.gov (United States)

    Beck, Kevin D.; Short, Kenneth R.; VanMeenen, Kirsten M.; Servatius, Richard J.

    2006-05-01

    This paper reviews research conducted by our laboratory exploring the possible use of acoustical stimuli as a tool for influencing behavior. Over the course of several programs, different types of acoustic stimuli have been evaluated for their effectiveness in disrupting targeting, balance, and high-order cognitive processes in both humans and animals. Escape responses are of particular use in this regard. An escape response serves not only as an objective measure of aversion, but as a potential substitute for ongoing behavior. We have also assessed whether the level of performance changes if the individual does not perform an escape response. In general these studies have both suggested certain types of sounds are more aversive or distracting than others. Although the laboratory development of additional stimuli needs to continue, we are taking the next step by testing some of the more effective stimuli in more applied experimental scenarios including those involving group dynamics.

  9. Acoustic classification of dwellings

    DEFF Research Database (Denmark)

    Berardi, Umberto; Rasmussen, Birgit

    2014-01-01

    Schemes for the classification of dwellings according to different building performances have been proposed in the last years worldwide. The general idea behind these schemes relates to the positive impact a higher label, and thus a better performance, should have. In particular, focusing on sound...... insulation performance, national schemes for sound classification of dwellings have been developed in several European countries. These schemes define acoustic classes according to different levels of sound insulation. Due to the lack of coordination among countries, a significant diversity in terms...... of descriptors, number of classes, and class intervals occurred between national schemes. However, a proposal “acoustic classification scheme for dwellings” has been developed recently in the European COST Action TU0901 with 32 member countries. This proposal has been accepted as an ISO work item. This paper...

  10. A Martian acoustic anemometer.

    Science.gov (United States)

    Banfield, Don; Schindel, David W; Tarr, Steve; Dissly, Richard W

    2016-08-01

    An acoustic anemometer for use on Mars has been developed. To understand the processes that control the interaction between surface and atmosphere on Mars, not only the mean winds, but also the turbulent boundary layer, the fluxes of momentum, heat and molecular constituents between surface and atmosphere must be measured. Terrestrially this is done with acoustic anemometers, but the low density atmosphere on Mars makes it challenging to adapt such an instrument for use on Mars. This has been achieved using capacitive transducers and pulse compression, and was successfully demonstrated on a stratospheric balloon (simulating the Martian environment) and in a dedicated Mars Wind Tunnel facility. This instrument achieves a measurement accuracy of ∼5 cm/s with an update rate of >20 Hz under Martian conditions.

  11. Acoustic leak detector in Monju steam generator

    International Nuclear Information System (INIS)

    Wachi, E.; Inoue, T.

    1990-01-01

    Acoustic leak detectors are equipped with the Monju steam generators for one of the R and D activities, which are the same type of the detectors developed in the PNC 50MW Steam Generator Test Facility. Although they are an additional leak detection system to the regular one in Monju SG, they would also detect the intermediate or large leaks of the SG tube failures. The extrapolation method of a background noise analysis is expected to be verified by Monju SG data. (author). 4 figs

  12. Photoacoustic imaging using acoustic reflectors to enhance planar arrays.

    Science.gov (United States)

    Ellwood, Robert; Zhang, Edward; Beard, Paul; Cox, Ben

    2014-12-01

    Planar sensor arrays have advantages when used for photoacoustic imaging: they do not require the imaging target to be enclosed, and they are easier to manufacture than curved arrays. However, planar arrays have a limited view of the acoustic field due to their finite size; therefore, not all of the acoustic waves emitted from a photoacoustic source can be recorded. This loss of data results in artifacts in the reconstructed photoacoustic image. A detection array configuration which combines a planar Fabry–Pérot sensor with perpendicular acoustic reflectors is described and experimentally implemented. This retains the detection advantages of the planar sensor while increasing the effective detection aperture in order to improve the reconstructed photoacoustic image.

  13. Osmotic Acoustic Source

    Science.gov (United States)

    2017-09-25

    one side of the radiating surface that is on the order of one meter the length and width of the plane of the enclosure. The walls of the enclosure...DEPARTMENT OF THE NAVY OFFICE OF COUNSEL NAVAL UNDERSEA WARFARE CENTER DIVISION 1176 HOWELL STREET NEWPORT Rl 02841-1708...across a semi-permeable membrane. (2) Description of the Prior Art [0004] Low frequency acoustic sources such as in a range of one to ten Hertz are

  14. The acoustics of snoring.

    Science.gov (United States)

    Pevernagie, Dirk; Aarts, Ronald M; De Meyer, Micheline

    2010-04-01

    Snoring is a prevalent disorder affecting 20-40% of the general population. The mechanism of snoring is vibration of anatomical structures in the pharyngeal airway. Flutter of the soft palate accounts for the harsh aspect of the snoring sound. Natural or drug-induced sleep is required for its appearance. Snoring is subject to many influences such as body position, sleep stage, route of breathing and the presence or absence of sleep-disordered breathing. Its presentation may be variable within or between nights. While snoring is generally perceived as a social nuisance, rating of its noisiness is subjective and, therefore, inconsistent. Objective assessment of snoring is important to evaluate the effect of treatment interventions. Moreover, snoring carries information relating to the site and degree of obstruction of the upper airway. If evidence for monolevel snoring at the site of the soft palate is provided, the patient may benefit from palatal surgery. These considerations have inspired researchers to scrutinize the acoustic characteristics of snoring events. Similarly to speech, snoring is produced in the vocal tract. Because of this analogy, existing techniques for speech analysis have been applied to evaluate snoring sounds. It appears that the pitch of the snoring sound is in the low-frequency range (noise-like', and has scattered energy content in the higher spectral sub-bands (>500 Hz). To evaluate acoustic properties of snoring, sleep nasendoscopy is often performed. Recent evidence suggests that the acoustic quality of snoring is markedly different in drug-induced sleep as compared with natural sleep. Most often, palatal surgery alters sound characteristics of snoring, but is no cure for this disorder. It is uncertain whether the perceived improvement after palatal surgery, as judged by the bed partner, is due to an altered sound spectrum. Whether some acoustic aspects of snoring, such as changes in pitch, have predictive value for the presence of

  15. Deep Water Ocean Acoustics

    Science.gov (United States)

    2015-10-19

    to a maximum of 143.1°. The back- azimuth as a function of frequency does show coherent behavior, at least within the observed 0.3° small time...level vs. Phone Number (similar to depth) as function of time as the source moved from 10-20 km away. The structure of this interference pattern...dimensional long-range acoustic propagation for improved localisation methods” Dr. Heaney visited Emanuel Coelho at CMRE in La Spezia Italy and

  16. Acoustic emission source modeling

    Directory of Open Access Journals (Sweden)

    Hora P.

    2010-07-01

    Full Text Available The paper deals with the acoustic emission (AE source modeling by means of FEM system COMSOL Multiphysics. The following types of sources are used: the spatially concentrated force and the double forces (dipole. The pulse excitation is studied in both cases. As a material is used steel. The computed displacements are compared with the exact analytical solution of point sources under consideration.

  17. Acoustically enhanced heat transport

    Energy Technology Data Exchange (ETDEWEB)

    Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: tan.ming.kwang@monash.edu [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States)

    2016-01-15

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  18. Acoustically enhanced heat transport

    Science.gov (United States)

    Ang, Kar M.; Yeo, Leslie Y.; Friend, James R.; Hung, Yew Mun; Tan, Ming K.

    2016-01-01

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ˜ 106 Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ˜ 10-9 m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ˜ 10-8 m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10-8 m with 106 Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  19. Ocean Acoustic Propagation and Coherence Studies

    Science.gov (United States)

    2015-09-30

    Propagation variability is an inescapable complicating factor for both active and passive sonar systems, and for underwater acoustic communications...framework, to be exploited in the use of underwater sound in shallow water. Our knowledge of acoustic field patterns in shallow water, building block...Ocean Acoustics and Signals Laboratory . Five acoustic studies are planned: 1. Canyon and slope acoustics : Identify purely geometrically controlled

  20. Fundamentals of Shallow Water Acoustics

    CERN Document Server

    Katsnelson, Boris; Lynch, James

    2012-01-01

    Shallow water acoustics (SWA), the study of how low and medium frequency sound propagates and scatters on the continental shelves of the world's oceans, has both technical interest and a large number of practical applications. Technically, shallow water poses an interesting medium for the study of acoustic scattering, inverse theory, and propagation physics in a complicated oceanic waveguide. Practically, shallow water acoustics has interest for geophysical exploration, marine mammal studies, and naval applications. Additionally, one notes the very interdisciplinary nature of shallow water acoustics, including acoustical physics, physical oceanography, marine geology, and marine biology. In this specialized volume, the authors, all of whom have extensive at-sea experience in U.S. and Russian research efforts, have tried to summarize the main experimental, theoretical, and computational results in shallow water acoustics, with an emphasis on providing physical insight into the topics presented.

  1. High-Frequency Seafloor Acoustics

    CERN Document Server

    Jackson, Darrell R

    2007-01-01

    High-Frequency Seafloor Acoustics is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. This exciting new title provides ready access to experimental data, theory, and models relevant to high-frequency seafloor acoustics and will be of interest to sonar engineers and researchers working in underwater acoustics. The physical characteristics of the seafloor affecting acoustic propagation and scattering are covered, including physical and geoacoustic properties and surface roughness. Current theories for acoustic propagation in sediments are presented along with corresponding models for reflection, scattering, and seafloor penetration. The main text is backed up by an extensive bibliography and technical appendices.

  2. Hybrid Speaker Recognition Using Universal Acoustic Model

    Science.gov (United States)

    Nishimura, Jun; Kuroda, Tadahiro

    We propose a novel speaker recognition approach using a speaker-independent universal acoustic model (UAM) for sensornet applications. In sensornet applications such as “Business Microscope”, interactions among knowledge workers in an organization can be visualized by sensing face-to-face communication using wearable sensor nodes. In conventional studies, speakers are detected by comparing energy of input speech signals among the nodes. However, there are often synchronization errors among the nodes which degrade the speaker recognition performance. By focusing on property of the speaker's acoustic channel, UAM can provide robustness against the synchronization error. The overall speaker recognition accuracy is improved by combining UAM with the energy-based approach. For 0.1s speech inputs and 4 subjects, speaker recognition accuracy of 94% is achieved at the synchronization error less than 100ms.

  3. Acoustic Imaging of Combustion Noise

    Science.gov (United States)

    Ramohalli, K. N.; Seshan, P. K.

    1984-01-01

    Elliposidal acoustic mirror used to measure sound emitted at discrete points in burning turbulent jets. Mirror deemphasizes sources close to target source and excludes sources far from target. At acoustic frequency of 20 kHz, mirror resolves sound from region 1.25 cm wide. Currently used by NASA for research on jet flames. Produces clearly identifiable and measurable variation of acoustic spectral intensities along length of flame. Utilized in variety of monitoring or control systems involving flames or other reacting flows.

  4. Systems and methods for biometric identification using the acoustic properties of the ear canal

    Science.gov (United States)

    Bouchard, Ann Marie; Osbourn, Gordon Cecil

    1998-01-01

    The present invention teaches systems and methods for verifying or recognizing a person's identity based on measurements of the acoustic response of the individual's ear canal. The system comprises an acoustic emission device, which emits an acoustic source signal s(t), designated by a computer, into the ear canal of an individual, and an acoustic response detection device, which detects the acoustic response signal f(t). A computer digitizes the response (detected) signal f(t) and stores the data. Computer-implemented algorithms analyze the response signal f(t) to produce ear-canal feature data. The ear-canal feature data obtained during enrollment is stored on the computer, or some other recording medium, to compare the enrollment data with ear-canal feature data produced in a subsequent access attempt, to determine if the individual has previously been enrolled. The system can also be adapted for remote access applications.

  5. Systems and methods for biometric identification using the acoustic properties of the ear canal

    International Nuclear Information System (INIS)

    Bouchard, A.M.; Osbourn, G.C.

    1998-01-01

    The present invention teaches systems and methods for verifying or recognizing a person's identity based on measurements of the acoustic response of the individual's ear canal. The system comprises an acoustic emission device, which emits an acoustic source signal s(t), designated by a computer, into the ear canal of an individual, and an acoustic response detection device, which detects the acoustic response signal f(t). A computer digitizes the response (detected) signal f(t) and stores the data. Computer-implemented algorithms analyze the response signal f(t) to produce ear-canal feature data. The ear-canal feature data obtained during enrollment is stored on the computer, or some other recording medium, to compare the enrollment data with ear-canal feature data produced in a subsequent access attempt, to determine if the individual has previously been enrolled. The system can also be adapted for remote access applications. 5 figs

  6. Coherent generation of acoustic phonons in an optical microcavity

    International Nuclear Information System (INIS)

    Lanzillotti-Kimura, N D; Fainstein, A; Huynh, A; Perrin, B; Jusserand, B; Miard, A; LemaItre, A

    2007-01-01

    Coherent acoustic phonons confined in a nanocavity are generated in an optical microcavity. The confinement of the femtosecond light pulse in the optical resonator amplifies both processes, generation and detection of the acoustic phonons. In addition, due to the standing wave character of the photon field, phonons of wavevector q = 0 and q = 2k (k is the light wavenumber) contribute to both the generation and detection in time resolved reflectivity measurements, further optimizing the pump and probe experiments. Time resolved differential reflectivity experiments are reported as a function of laser energy. The optical cavity resonance is apparent in the amplitude and spectral features of the Fourier transformed signals

  7. In process acoustic emission in multirun submerged arc welding

    International Nuclear Information System (INIS)

    Asty, M.; Birac, C.

    1980-01-01

    In order to avoid the formation of deep grooves when repairing defects in welded joints in heavy plates, an investigation was made aiming to detect and locate the defects by in-process acoustic emission in multirun submerged arc welding. Twelve defects (lack of penetration, cracks, inclusions, lack of fusion together with inclusions, blowholes) were intentionally introduced when the first plate was welded. A space-time method for processing the acoustic activity during welding allowed the detection and the location of the intentional defects as well as of the most important accidental defects evidenced by ultrasonic testing [fr

  8. Tunable coupled surface acoustic cavities

    Science.gov (United States)

    de Lima, M. M.; Santos, P. V.; Kosevich, Yu. A.; Cantarero, A.

    2012-06-01

    We demonstrate the electric tuning of the acoustic field in acoustic microcavities (MCs) defined by a periodic arrangement of metal stripes within a surface acoustic delay line on LiNbO3 substrate. Interferometric measurements show the enhancement of the acoustic field distribution within a single MC, the presence of a "bonding" and "anti-bonding" modes for two strongly coupled MCs, as well as the positive dispersion of the "mini-bands" formed by five coupled MCs. The frequency and amplitude of the resonances can be controlled by the potential applied to the metal stripes.

  9. Sinusoidal Representation of Acoustic Signals

    Science.gov (United States)

    Honda, Masaaki

    Sinusoidal representation of acoustic signals has been an important tool in speech and music processing like signal analysis, synthesis and time scale or pitch modifications. It can be applicable to arbitrary signals, which is an important advantage over other signal representations like physical modeling of acoustic signals. In sinusoidal representation, acoustic signals are composed as sums of sinusoid (sine wave) with different amplitudes, frequencies and phases, which is based on the timedependent short-time Fourier transform (STFT). This article describes the principles of acoustic signal analysis/synthesis based on a sinusoid representation with focus on sine waves with rapidly varying frequency.

  10. Acoustic Communications Measurement Systems (ACOMMS)

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Design and develop adaptive signal processing techniques to improve underwater acoustic communications and networking. Phase coherent and incoherent signal...

  11. NDE Acoustic Microscopy Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The purpose is to develop advanced, more effective high-resolution micro-NDE materials characterization methods using scanning acoustic microscopy. The laboratory's...

  12. Combined Environment Acoustic Chamber (CEAC)

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The CEAC imposes combined acoustic, thermal and mechanical loads on aerospace structures. The CEAC is employed to measure structural response and determine...

  13. Surface Modification on Acoustic Wave Biosensors for Enhanced Specificity

    Directory of Open Access Journals (Sweden)

    Nathan D. Gallant

    2012-09-01

    Full Text Available Changes in mass loading on the surface of acoustic biosensors result in output frequency shifts which provide precise measurements of analytes. Therefore, to detect a particular biomarker, the sensor delay path must be judiciously designed to maximize sensitivity and specificity. B-cell lymphoma 2 protein (Bcl-2 found in urine is under investigation as a biomarker for non-invasive early detection of ovarian cancer. In this study, surface chemistry and biofunctionalization approaches were evaluated for their effectiveness in presenting antibodies for Bcl-2 capture while minimizing non-specific protein adsorption. The optimal combination of sequentially adsorbing protein A/G, anti-Bcl-2 IgG and Pluronic F127 onto a hydrophobic surface provided the greatest signal-to-noise ratio and enabled the reliable detection of Bcl-2 concentrations below that previously identified for early stage ovarian cancer as characterized by a modified ELISA method. Finally, the optimal surface modification was applied to a prototype acoustic device and the frequency shift for a range of Bcl-2 concentration was quantified to demonstrate the effectiveness in surface acoustic wave (SAW-based detection applications. The surface functionalization approaches demonstrated here to specifically and sensitively detect Bcl-2 in a working ultrasonic MEMS biosensor prototype can easily be modified to detect additional biomarkers and enhance other acoustic biosensors.

  14. Acoustic Search for High Energy Neutrinos in Lake Baikal: Status and Perspectives

    Directory of Open Access Journals (Sweden)

    Budnev N.M.

    2017-01-01

    Full Text Available The status and perspectives of the feasibility study to detect high energy cosmic neutrinos acoustically in Lake Baikal is presented. The concept of on acoustic array as a part of the Baikal Gigaton Volume Neutrino Telescope GVD based on results of simulation and background measurements is described.

  15. Evaluation of potential bias in observing fish by a DIDSON acoustic camera

    Czech Academy of Sciences Publication Activity Database

    Tušer, Michal; Frouzová, Jaroslava; Balk, Helge; Muška, Milan; Mrkvička, Tomáš; Kubečka, Jan

    2014-01-01

    Roč. 155, July (2014), s. 114-121 ISSN 0165-7836 R&D Projects: GA MŠk(CZ) EE2.3.20.0204 Institutional support: RVO:60077344 Keywords : DIDSON * fish detection * length measurement * horizontal body orientation * acoustic data processing Subject RIV: BI - Acoustics Impact factor: 1.903, year: 2014

  16. Nondestructive online testing method for friction stir welding using acoustic emission

    Science.gov (United States)

    Levikhina, Anastasiya

    2017-12-01

    The paper reviews the possibility of applying the method of acoustic emission for online monitoring of the friction stir welding process. It is shown that acoustic emission allows the detection of weld defects and their location in real time. The energy of an acoustic signal and the median frequency are suggested to be used as informative parameters. The method of calculating the median frequency with the use of a short time Fourier transform is applied for the identification of correlations between the defective weld structure and properties of the acoustic emission signals received during welding.

  17. Acoustic transparency and slow sound using detuned acoustic resonators

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco; Bozhevolnyi, Sergey I.

    2011-01-01

    We demonstrate that the phenomenon of acoustic transparency and slowsound propagation can be realized with detuned acoustic resonators (DAR), mimicking thereby the effect of electromagnetically induced transparency (EIT) in atomic physics. Sound propagation in a pipe with a series of side...

  18. Double negative acoustic metastructure for attenuation of acoustic emissions

    Science.gov (United States)

    Kumar, Sanjay; Bhushan, Pulak; Prakash, Om; Bhattacharya, Shantanu

    2018-03-01

    Acoustic metamaterials hold great potential for attenuation of low frequency acoustic emissions. However, a fundamental challenge is achieving high transmission loss over a broad frequency range. In this work, we report a double negative acoustic metastructure for absorption of low frequency acoustic emissions in an aircraft. This is achieved by utilizing a periodic array of hexagonal cells interconnected with a neck and mounted with an elastic membrane on both ends. An average transmission loss of 56 dB under 500 Hz and an overall absorption of over 48% have been realized experimentally. The negative mass density is derived from the dipolar resonances created as a result of the in-phase movement of the membranes. Further, the negative bulk modulus is ascribed to the combined effect of out-of-phase acceleration of the membranes and the Helmholtz resonator. The proposed metastructure enables absorption of low frequency acoustic emissions with improved functionality that is highly desirable for varied applications.

  19. Acoustic Mechanical Feedthroughs

    Science.gov (United States)

    Sherrit, Stewart; Walkemeyer, Phillip; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea

    2013-01-01

    Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be

  20. Surface Acoustic Wave Devices

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    application is modulation of optical waves in waveguides. This presentation elaborates on how a SAW is generated by interdigital transducers using a 2D model of a piezoelectric, inhomogeneous material implemented in the high-level programming language Comsol Multiphysics. The SAW is send through a model......The work of this project is concerned with the simulation of surface acoustic waves (SAW) and topology optimization of SAW devices. SAWs are elastic vibrations that propagate along a material surface and are extensively used in electromechanical filters and resonators in telecommunication. A new...