Sample records for acoustic analysis presenting

  1. Auditorium Acoustics From Past to Present

    Directory of Open Access Journals (Sweden)

    Kabiru Maishanu


    Full Text Available The main aim of this paper is to identify how acoustics where generally achieve in auditoriums base on the method, technics and the materials been used. This paper will discuss the transition over time. It will cover how the design began from the past (Roman, Greek baroque, renaissance periods to the present (twentieth century. The paper will further discuss some case studies which are from different periods. The selection of the case study was based on their excellent acoustics qualities of the spaces. It will provide better understanding on how acoustics solution where been achieve in auditoriums/theaters from the past to the present. Finally, the paper will point out some major benefits of using acoustics in auditoriums and also discuss on what causes poor quality sound in the present auditoriums and then suggest the use flat panels technology and line-stone material as it has great impact in in achieving good and qualitative acoustics in the past.

  2. Isogeometric analysis of acoustic scattering


    Venås, Jon Vegard


    Acoustic scattering has been thoroughly analyzed with the use of finite element analysis (FEA). The problem at hand is a coupled fluid-structure interaction problem on an unbounded domain, where an object of elastic material is surrounded by fluid. Using physical assumptions, the fluid is described by the wave equation which is transformed to the Helmholtz equation. That is, the frequency domain is considered instead of the time domain. In particular one is interested in the scattered pressur...

  3. Present status of the South Pole acoustic test setup (SPATS)

    Energy Technology Data Exchange (ETDEWEB)

    Tosi, D.; Boeser, S.; Fischer, J.H.; Heller, R.; Krieger, K.; Nahnhauer, R.; Pohl, M.; Sulanke, K.H. [DESY, Zeuthen (Germany); Bohm, C.; Hundertmark, S. [Stockholm Univ. (Sweden); Descamps, F. [DESY, Zeuthen (Germany); Ghent Univ. (Belgium); Hallgren, A. [Uppsala Univ. (Sweden); Price, B.; Vandenbroucke, J. [Univ. of California, Berkeley, CA (United States)


    Acoustic detection in ice is a promising method to investigate the low flux of ultra high energy neutrinos (E>10{sup 18} eV). Due to the long predicted attenuation length of acoustic waves generated by neutrino-induced cascades, a volume of several km{sup 3}, as available in the polar ice cap, may be equipped with sparse sensors. In order to study in-situ the absorption, the refraction of sound and the background noise, the South Pole Acoustic Test Setup (SPATS), consisting of 21 pairs of sensors and transmitters organized in 3 strings, has been developed. Low temperature tests simulating the harsh South Pole environment and long range tests in an ice-covered lake have been undertaken. The results obtained demonstrate the robustness of the setup and allow a first estimate of the expected performance. A simulation showing the capability of the system concerning refraction and absorptivity of the ice is presented, together with the first results of the installed setup, which is planned to be deployed in the austral summer season 2006-2007. (orig.)

  4. Analysis of Cummer-Schurig acoustic cloaking

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    Cai Liangwu [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Sanchez-Dehesa, Jose [Wave Phenomena Group, Department of Electronic Engineering, Polytechnic University of Valencia, C/Camino de Vera s.n., E-46022 Valencia (Spain)


    This paper presents an in-depth analysis of the scattering characteristics of the Cummer-Schurig acoustic cloaking design proposed by Cummer and Schurig (2007 New J. Phys. 9 45). The analysis uses an analytical solution for orthotropic media in conjunction with approximating the radially varying properties by multiple layers of uniform shells. The analysis shows that the cloaking is effective for both planar incident waves and line sources, but not perfect for the entire computed spatial frequency range up to ka=10, where k is the wavenumber in the host medium and a is the outer radius of the cloaking shell. Furthermore, the cloaking remains effective but less perfect when the cloaked region is not rigid. For a penetrable medium in the cloaked region, the cloaking is penetrated only at the resonant frequencies.

  5. Acoustic neuroma ingrowth in the cochlear nerve: does it influence the clinical presentation?

    NARCIS (Netherlands)

    Forton, G.E.J.; Cremers, C.W.R.J.; Offeciers, E.E.


    We examined the clinical presentation in patients with a histologically proven ingrowth of the cochlear nerve by acoustic neuroma to see whether this differs from what is known from large acoustic neuroma series. In total, 85 acoustic neuromas had an en bloc dissection to study histologically the

  6. Perception of acoustically presented time series with varied intervals. (United States)

    Wackermann, Jiří; Pacer, Jakob; Wittmann, Marc


    Data from three experiments on serial perception of temporal intervals in the supra-second domain are reported. Sequences of short acoustic signals ("pips") separated by periods of silence were presented to the observers. Two types of time series, geometric or alternating, were used, where the modulus 1+δ of the inter-pip series and the base duration Tb (range from 1.1 to 6s) were varied as independent parameters. The observers had to judge whether the series were accelerating, decelerating, or uniform (3 paradigm), or to distinguish regular from irregular sequences (2 paradigm). "Intervals of subjective uniformity" (isus) were obtained by fitting Gaussian psychometric functions to individual subjects' responses. Progression towards longer base durations (Tb=4.4 or 6s) shifts the isus towards negative δs, i.e., accelerating series. This finding is compatible with the phenomenon of "subjective shortening" of past temporal intervals, which is naturally accounted for by the lossy integration model of internal time representation. The opposite effect observed for short durations (Tb=1.1 or 1.5s) remains unexplained by the lossy integration model, and presents a challenge for further research. © 2013 Elsevier B.V. All rights reserved.

  7. Acoustic Gaits: Gait Analysis With Footstep Sounds. (United States)

    Altaf, M Umair Bin; Butko, Taras; Juang, Biing-Hwang Fred


    We describe the acoustic gaits-the natural human gait quantitative characteristics derived from the sound of footsteps as the person walks normally. We introduce the acoustic gait profile, which is obtained from temporal signal analysis of sound of footsteps collected by microphones and illustrate some of the spatio-temporal gait parameters that can be extracted from the acoustic gait profile by using three temporal signal analysis methods-the squared energy estimate, Hilbert transform and Teager-Kaiser energy operator. Based on the statistical analysis of the parameter estimates, we show that the spatio-temporal parameters and gait characteristics obtained using the acoustic gait profile can consistently and reliably estimate a subset of clinical and biometric gait parameters currently in use for standardized gait assessments. We conclude that the Teager-Kaiser energy operator provides the most consistent gait parameter estimates showing the least variation across different sessions and zones. Acoustic gaits use an inexpensive set of microphones with a computing device as an accurate and unintrusive gait analysis system. This is in contrast to the expensive and intrusive systems currently used in laboratory gait analysis such as the force plates, pressure mats and wearable sensors, some of which may change the gait parameters that are being measured.

  8. Acoustic analysis of speech under stress. (United States)

    Sondhi, Savita; Khan, Munna; Vijay, Ritu; Salhan, Ashok K; Chouhan, Satish


    When a person is emotionally charged, stress could be discerned in his voice. This paper presents a simplified and a non-invasive approach to detect psycho-physiological stress by monitoring the acoustic modifications during a stressful conversation. Voice database consists of audio clips from eight different popular FM broadcasts wherein the host of the show vexes the subjects who are otherwise unaware of the charade. The audio clips are obtained from real-life stressful conversations (no simulated emotions). Analysis is done using PRAAT software to evaluate mean fundamental frequency (F0) and formant frequencies (F1, F2, F3, F4) both in neutral and stressed state. Results suggest that F0 increases with stress; however, formant frequency decreases with stress. Comparison of Fourier and chirp spectra of short vowel segment shows that for relaxed speech, the two spectra are similar; however, for stressed speech, they differ in the high frequency range due to increased pitch modulation.

  9. Underwater acoustic communication research at TNO-Past and present

    NARCIS (Netherlands)

    Dol, H.; Walree, P. van


    This paper provides an overview of more than 12 years of underwater acoustic communication research at the Sonar Department of TNO The Hague. The research covered both point-to-point links and relay networks, from long-range covert communication to short-range high-data-rate communication, for both

  10. Pressure potential and stability analysis in an acoustical noncontact transportation (United States)

    Li, J.; Liu, C. J.; Zhang, W. J.


    Near field acoustic traveling wave is one of the most popular principles in noncontact manipulations and transportations. The stability behavior is a key factor in the industrial applications of acoustical noncontact transportation. We present here an in-depth analysis of the transportation stability of a planar object levitated in near field acoustic traveling waves. To more accurately describe the pressure distributions on the radiation surface, a 3D nonlinear traveling wave model is presented. A closed form solution is derived based on the pressure potential to quantitatively calculate the restoring forces and moments under small disturbances. The physical explanations of the effects of fluid inertia and the effects of non-uniform pressure distributions are provided in detail. It is found that a vibration rail with tapered cross section provides more stable transportation than a rail with rectangular cross section. The present study sheds light on the issue of quantitative evaluation of stability in acoustic traveling waves and proposes three main factors that influence the stability: (a) vibration shape, (b) pressure distribution and (c) restoring force/moment. It helps to provide a better understanding of the physics behind the near field acoustic transportation and provide useful design and optimization tools for industrial applications.

  11. COI Structural Analysis Presentation (United States)

    Cline, Todd; Stahl, H. Philip (Technical Monitor)


    This report discusses the structural analysis of the Next Generation Space Telescope Mirror System Demonstrator (NMSD) developed by Composite Optics Incorporated (COI) in support of the Next Generation Space Telescope (NGST) project. The mirror was submitted to Marshall Space Flight Center (MSFC) for cryogenic testing and evaluation. Once at MSFC, the mirror was lowered to approximately 40 K and the optical surface distortions were measured. Alongside this experiment, an analytical model was developed and used to compare to the test results. A NASTRAN finite element model was provided by COI and a thermal model was developed from it. Using the thermal model, steady state nodal temperatures were calculated based on the predicted environment of the large cryogenic test chamber at MSFC. This temperature distribution was applied in the structural analysis to solve for the deflections of the optical surface. Finally, these deflections were submitted for optical analysis and comparison to the interferometer test data.

  12. Dynamic response analysis of an aircraft structure under thermal-acoustic loads (United States)

    Cheng, H.; Li, H. B.; Zhang, W.; Wu, Z. Q.; Liu, B. R.


    Future hypersonic aircraft will be exposed to extreme combined environments includes large magnitude thermal and acoustic loads. It presents a significant challenge for the integrity of these vehicles. Thermal-acoustic test is used to test structures for dynamic response and sonic fatigue due to combined loads. In this research, the numerical simulation process for the thermal acoustic test is presented, and the effects of thermal loads on vibro-acoustic response are investigated. To simulate the radiation heating system, Monte Carlo theory and thermal network theory was used to calculate the temperature distribution. Considering the thermal stress, the high temperature modal parameters are obtained with structural finite element methods. Based on acoustic finite element, modal-based vibro-acoustic analysis is carried out to compute structural responses. These researches are very vital to optimum thermal-acoustic test and structure designs for future hypersonic vehicles structure

  13. A comparison between acoustic mode measurements and acoustic finite element analysis performed for SAAB SF 340 (United States)

    Goeransson, P.; Green, I.


    In order to verify an acoustic finite element package, measured and calculated eigenmodes and eigenfrequencies for Saab SF 340 cabin acoustics were compared. The measurements were performed in an acoustic mockup. For the analysis, a two dimensional model of the cross section of the fuselage was used. The comparison shows quite good agreement, the discrepancies being due to the representation of the flexible wall of the fuselage as rigid in the analysis.

  14. Bridge cable fracture detection with acoustic emission test (Conference Presentation) (United States)

    Qu, Hongya; Li, Tiantian; Chen, Genda


    In this study, acoustic emission (AE) tests were conducted to detect and locate wire fracture in strands that are widely used in cable-stayed and suspension bridges. To effectively separate fracture signals from unwanted noises, distinct features of fracture, fracture-induced echo, and artificial tapping signals as well as their dependence on loading levels are characterized with short-time Fourier transform. To associate fracture scenarios with their acoustic features, two 20-foot-long ( 6.1 m) 270 ksi ( 1,862 MPa) steel strands of seven wires were tested with one wire notched off at center and support, respectively, up to 90% of its cross section area by 10% increment. Up to 80% reduction in cross section area of the notched wire, each strand was loaded to 20 kips ( 89 kN) corresponding to 35% of the minimum breaking strength and the acquired AE parameters such as hits, energy, and counts were found to change little. With a reduction of 90% of the section area of one wire, both strands were found to be fractured under approximately 16.5 kips ( 73.4 kN). The hits, energy, and counts of AE signals were all demonstrated to suddenly change with the fracture of the notched wire. However, only the counts of AE signals distributed over the length of the strands allow the localization of fracture point. The frequency band of fracture signals is significantly broader than that of either fracture-induced echo or artificial tapping noise. The time duration of artificial tapping noises is substantially longer than that of either fracture or fracture-induced echo. These distinct characteristics can be used to effectively separate fracture signals from noises for wire fracture detection and localization in practice.

  15. Acoustic analysis of a semi-anechoic chamber with intersection


    P. Nassiri; M. R. Monazzam; F. Zivary Delavar


    Introduction: The previous studies have used fibrous absorbents usually in the form of cone-shaped wedges for making anechoic and semi-anechoic chambers which their design and construction have been costly and difficult. The present study aimed to design a semi-anechoic chamber, using rectangular fibrous absorbents and also perform acoustic analysis for it. . Material and Method: In the present study, which was done at semi-anechoic chamber of the laboratory in Tehran University of Medical...

  16. Multidimensional acoustic analysis of pathological voice

    Directory of Open Access Journals (Sweden)

    Petrović-Lazić Mirjana


    Full Text Available Introduction. There are subjective and objective ways to examine the effects of vocal therapy in voice disorders. The most precise and objective check-up is the use of computer voice analysis. Objective. The aim of the research was to perform a detailed analysis of acoustic structure of the vowel A before and after voice treatment in patients with vocal fold nodules in order to obtain objective verification of the vocal rehabilitation success. Methods. We examined 30 female patients, aged 34.6±6.69 years, with vocal fold nodules. Acoustic parameters of voice were compared with the control group consisting of 21 subjects without voice pathology. In all persons the vowel A was recorded and analyzed before and after a month of vocal therapy. The success of the vocal therapy was tracked using computer analysis of vocal structure. Signal, noise and tremor parameters were processed. Results. Of the analyzed vowel A parameters: STD, PER, JITA, JITT, RAP, vFO, ShdB, SHIM, APQ, VTI, SPI, F0, NHR, FTRI, eleven improved (p<0.05 and p<0.01. Three parameters (F0, NHR, FTRI changed showing improvement, but the obtained differences were not statistically significant (p>0.05. Conclusion. Based on the obtained results it was concluded that vocal therapy gave satisfactory results, but that it should be continually applied until full stabilization of the voice.

  17. Acoustic streaming jets: A scaling and dimensional analysis

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    Botton, V., E-mail:; Henry, D.; Millet, S.; Ben-Hadid, H. [LMFA, UMR CNRS 5509, Université de Lyon, ECL/INSA Lyon/Univ. Lyon 1, 36 avenue Guy deCollongue, 69134 Ecully Cedex (France); Moudjed, B. [LMFA, UMR CNRS 5509, Université de Lyon, ECL/INSA Lyon/Univ. Lyon 1, 36 avenue Guy deCollongue, 69134 Ecully Cedex (France); LIEFT, CEA-Saclay, 91191 Gif-sur-Yvette cedex (France); Garandet, J. P. [LIEFT, CEA-Saclay, 91191 Gif-sur-Yvette cedex (France)


    We present our work on acoustic streaming free jets driven by ultrasonic beams in liquids. These jets are steady flows generated far from walls by progressive acoustic waves. As can be seen on figure 1, our set-up, denominated AStrID for Acoustic Streaming Investigation Device, is made of a water tank in which a 29 mm plane source emits continuous ultrasonic waves at typically 2 MHz. Our approach combines an experimental characterization of both the acoustic pressure field (hydrophone) and the obtained acoustic streaming velocity field (PIV visualization) on one hand, with CFD using an incompressible Navier-Stokes solver on the other hand.

  18. Acoustic impact testing and waveform analysis for damage detection in glued laminated timber (United States)

    Feng Xu; Xiping Wang; Marko Teder; Yunfei Liu


    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...

  19. Analysis of acoustic emission data for bearings subject to unbalance

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    Rapinder Sawhney


    Full Text Available Acoustic Emission (AE is an effective nondestructive method for investigating the behavior of materials under stress. In recent decades, AE applications in structural health monitoring have been extended to other areas such as rotating machineries and cutting tools. This research investigates the application of acoustic emission data for unbalance analysis and detection in rotary systems. The AE parameter of interest in this study is a discrete variable that covers the significance of count, duration and amplitude of AE signals. A statistical model based on Zero-Inflated Poisson (ZIP regression is proposed to handle over-dispersion and excess zeros of the counting data. The ZIP model indicates that faulty bearings can generate more transient wave in the AE waveform. Control charts can easily detect the faulty bearing using the parameters of the ZIP model. Categorical data analysis based on generalized linear models (GLM is also presented. The results demonstrate the significance of the couple unbalance.

  20. Ambient Noise Analysis of Acoustic Data from the Philippine Sea (United States)


    09-17 FROM: David P. Knobles TO: Ellen S. Livingston, ONR 321 SUBJECT: Final Report for N00014-07-1-0263, Task Description Title: Ambient Noise...Analysis of Acoustic Data from the Philippine Sea Ambient noise analysis of acoustic data from the Philippine Sea The objective of this research...was to use recovered acoustic data recorded on analog tapes in the late 1970s to early 1980s to assist in characterizing the ambient noise properties

  1. Acoustical analysis of gear housing vibration (United States)

    Seybert, A. F.; Wu, T. W.; Wu, X. F.; Oswald, Fred B.


    The modal and acoustical analysis of the NASA gear-noise rig is described. Experimental modal analysis techniques were used to determine the modes of vibration of the transmission housing. The resulting modal data were then used in a boundary element method (BEM) analysis to calculate the sound pressure and sound intensity on the surface of the housing as well as the radiation efficiency of each mode. The radiation efficiencies of the transmission housing modes are compared with theoretical results for finite, baffled plates. A method that uses the measured mode shapes and the BEM to predict the effect of simple structural changes on the sound radiation efficiency of the modes of vibration is also described.

  2. Acoustic analysis of voice: Iranian teachers. (United States)

    Dehqan, Ali; Scherer, Ronald C


    In Iran, the total number of elementary schoolteachers is estimated to be nearly 300 000 people and this population is at risk for developing voice disorders. Acoustical characteristics of voice for schoolteachers in Iran are unknown but are relevant to the quantitative description, diagnosis, intervention, reassessment, and outcomes of their voices. Fifteen female and 15 male Iranian primary schoolteachers in the age range of 35-40 years with 15 years teaching experience volunteered to participate in the study. The control group consisted of 30 Iranian adults aged 35-40 years (15 men and 15 women). Recordings and audio signal analyses were carried out using Praat software. Each subject was asked to sustain the vowel /â/ using habitual and constant vocal pitch, loudness, and quality for at least 5 seconds. Five tokens from each subject were obtained. For the male subjects, the results indicated no significant difference (at the 0.05 level) for each variable between the two groups. However, for the female subjects, t tests showed significant differences between the teachers and the nonteacher controls in all parameters at the 0.01 level. The Iranian female teachers had significantly lower F(0) (190.27 Hz) than the control group (236.32 Hz). Also, for the perturbation acoustic parameters (jitter% and shimmer%), the female teacher group had significantly higher values than their corresponding control group. Similarly, the harmonics-to-noise ratio (HNR) measures for the Iranian female teacher population were significantly lower than for their corresponding control group. The results indicate that female Iranian teachers appear to be more susceptible to voice stability change than the male Iranian teachers. Also, acoustic analysis of voice for teachers may significantly contribute to the objective voice examination of this group. Further investigations of factors that promote individual susceptibility to vocal stability are necessary. Copyright © 2013 The Voice

  3. The application of cochlear audio analysis techniques to electro-acoustic music (United States)

    Mills, John A.


    Electro-acoustic music has been ignored by music theorists for years. One theory suggests that this deficiency is due to the lack of an objective visual representation of this type of music. This research is focused upon the audio analysis involved in the creation of a ``pseudoscore'' for electro-acoustic music. Computer analysis of music is a complicated task. The ``holy grail'' of automatic computer music analysis has most often been the translation of a continuous pressure variation into traditional Western musical notation. Since electro-acoustic music is rarely able to be transcribed into this type of notation, the automatic analysis of electro-acoustic music confounds many previous algorithms. A top-down approach is suggested in order to extract acoustic and musical information from recordings of electro-acoustics music. A top-down approach has already proven successful in extraction of musical tempo [E. Scheirer, M.I.T. Ph.D. thesis (2000)]. Since humans are able to translate a continuous pressure variation into useful acoustic information, when using a top-down approach to automatic music analysis, a cochlear model is used as a front end. Although this model apparently encodes some redundant information, cross- and auto-correlation techniques allow easier extraction of some acoustic information. This presentation will detail the current state of this research.

  4. Acoustofluidics 13: Analysis of acoustic streaming by perturbation methods. (United States)

    Sadhal, S S


    In this Part 13 of the tutorial series "Acoustofluidics--exploiting ultrasonic standing waves forces and acoustic streaming in microfluidic systems for cell and particle manipulation," the streaming phenomenon is presented from an analytical standpoint, and perturbation methods are developed for analyzing such flows. Acoustic streaming is the phenomenon that takes place when a steady flow field is generated by the absorption of an oscillatory field. This can happen either by attenuation (quartz wind) or by interaction with a boundary. The latter type of streaming can also be generated by an oscillating solid in an otherwise still fluid medium or vibrating enclosure of a fluid body. While we address the first kind of streaming, our focus is largely on the second kind from a practical standpoint for application to microfluidic systems. In this Focus article, we limit the analysis to one- and two-dimensional problems in order to understand the analytical techniques with examples that most-easily illustrate the streaming phenomenon.

  5. [Acoustic analysis in different background of hearing]. (United States)

    Liu, Yun; Zhang, Daoxing; Liu, Yongxiang


    To find out the changes of voice in different noisy background by computer acoustic analysis. Twenty-five young people who got normal hearing level and normal vocal cords were selected. They were tested after trained. Sustained /a/,/i/ and sentences were recorded in the three different background: quite, white band noise and speech noise. The software of MDVP was used. Testing parameters included: F0, Jitter, Shimmer, APQ, PPQ, HNR. Fundamental frequencies of noisy groups are significantly higher in male-/a/, female-/a/ and female-/i/ groups. The perturbations are not significantly different among them. The HNR is negatively relative with F0. Normal hearing persons increase their fundamental frequencies in the noisy surroundings.

  6. Linear Stability Analysis of an Acoustically Vaporized Droplet (United States)

    Siddiqui, Junaid; Qamar, Adnan; Samtaney, Ravi


    Acoustic droplet vaporization (ADV) is a phase transition phenomena of a superheat liquid (Dodecafluoropentane, C5F12) droplet to a gaseous bubble, instigated by a high-intensity acoustic pulse. This approach was first studied in imaging applications, and applicable in several therapeutic areas such as gas embolotherapy, thrombus dissolution, and drug delivery. High-speed imaging and theoretical modeling of ADV has elucidated several physical aspects, ranging from bubble nucleation to its subsequent growth. Surface instabilities are known to exist and considered responsible for evolving bubble shapes (non-spherical growth, bubble splitting and bubble droplet encapsulation). We present a linear stability analysis of the dynamically evolving interfaces of an acoustically vaporized micro-droplet (liquid A) in an infinite pool of a second liquid (liquid B). We propose a thermal ADV model for the base state. The linear analysis utilizes spherical harmonics (Ynm, of degree m and order n) and under various physical assumptions results in a time-dependent ODE of the perturbed interface amplitudes (one at the vapor/liquid A interface and the other at the liquid A/liquid B interface). The perturbation amplitudes are found to grow exponentially and do not depend on m. Supported by KAUST Baseline Research Funds.

  7. Vibro-acoustic modeling and analysis of a coupled acoustic system comprising a partially opened cavity coupled with a flexible plate (United States)

    Shi, Shuangxia; Su, Zhu; Jin, Guoyong; Liu, Zhigang


    This paper is concerned with the modeling and solution method of a three-dimensional (3D) coupled acoustic system comprising a partially opened cavity coupled with a flexible plate and an exterior field of semi-infinite size, which is ubiquitously encountered in architectural acoustics and is a reasonable representation of many engineering occasions. A general solution method is presented to predict the dynamic behaviors of the three-dimensional (3D) acoustic coupled system, in which the displacement of the plate and the sound pressure in the cavity are respectively constructed in the form of the two-dimensional and three-dimensional modified Fourier series with several auxiliary functions introduced to ensure the uniform convergence of the solution over the entire solution domain. The effect of the opening is taken into account via the work done by the sound pressure acting at the coupling aperture that is contributed from the vibration of particles on the acoustic coupling interface and on the structural-acoustic coupling interface. Both the acoustic coupling between finite cavity and exterior field and the structural-acoustic coupling between flexible plate and interior acoustic field are considered in the vibro-acoustic modeling of the three-dimensional acoustic coupled acoustic system. The dynamic responses of the coupled structural-acoustic system are obtained using the Rayleigh-Ritz procedure based on the energy expressions for the coupled system. The accuracy and effectiveness of the proposed method are validated through numerical examples and comparison with results obtained by the boundary element analysis. Furthermore, the influence of the opening and the cavity volume on the acoustic behaviors of opened cavity system is studied.

  8. Standardization of pitch-range settings in voice acoustic analysis. (United States)

    Vogel, Adam P; Maruff, Paul; Snyder, Peter J; Mundt, James C


    Voice acoustic analysis is typically a labor-intensive, time-consuming process that requires the application of idiosyncratic parameters tailored to individual aspects of the speech signal. Such processes limit the efficiency and utility of voice analysis in clinical practice as well as in applied research and development. In the present study, we analyzed 1,120 voice files, using standard techniques (case-by-case hand analysis), taking roughly 10 work weeks of personnel time to complete. The results were compared with the analytic output of several automated analysis scripts that made use of preset pitch-range parameters. After pitch windows were selected to appropriately account for sex differences, the automated analysis scripts reduced processing time of the 1,120 speech samples to less than 2.5 h and produced results comparable to those obtained with hand analysis. However, caution should be exercised when applying the suggested preset values to pathological voice populations.

  9. Acoustic analysis assessment in speech pathology detection

    Directory of Open Access Journals (Sweden)

    Panek Daria


    Full Text Available Automatic detection of voice pathologies enables non-invasive, low cost and objective assessments of the presence of disorders, as well as accelerating and improving the process of diagnosis and clinical treatment given to patients. In this work, a vector made up of 28 acoustic parameters is evaluated using principal component analysis (PCA, kernel principal component analysis (kPCA and an auto-associative neural network (NLPCA in four kinds of pathology detection (hyperfunctional dysphonia, functional dysphonia, laryngitis, vocal cord paralysis using the a, i and u vowels, spoken at a high, low and normal pitch. The results indicate that the kPCA and NLPCA methods can be considered a step towards pathology detection of the vocal folds. The results show that such an approach provides acceptable results for this purpose, with the best efficiency levels of around 100%. The study brings the most commonly used approaches to speech signal processing together and leads to a comparison of the machine learning methods determining the health status of the patient

  10. Presentation : Spatial Analysis and GEOmatics


    Didier Josselin; Thérèse Libourel


    SAGEO is the annual International Conference on Spatial Analysis and GEOmatics. It aims to:  present recent and high quality research in the field of Geomatics and Spatial Analysis, bring together researchers from various disciplines, provide an exchange platform on research and development in Geomatics, on a national and international level, for public or private bodies. SAGEO is a good opportunity for two complementary research networks to meet and to discuss their points of view on spatial...

  11. Graphical Acoustic Liner Design and Analysis Tool (United States)

    Howerton, Brian M. (Inventor); Jones, Michael G. (Inventor)


    An interactive liner design and impedance modeling tool comprises software utilized to design acoustic liners for use in constrained spaces, both regularly and irregularly shaped. A graphical user interface allows the acoustic channel geometry to be drawn in a liner volume while the surface impedance calculations are updated and displayed in real-time. A one-dimensional transmission line model may be used as the basis for the impedance calculations.

  12. Design and Analysis of Underwater Acoustic Networks with Reflected Links (United States)

    Emokpae, Lloyd

    -of-sight (LOS) and NLOS links by utilizing directional antennas, which will boost the signal-to-noise ratio (SNR) at the receiver while promoting NLOS usage. In our model, we employ a directional underwater acoustic antenna composed of an array of hydrophones that can be summed up at various phases and amplitudes resulting in a beam-former. We have also adopted a practical multimodal directional transducer concept which generates both directional and omni-directional beam patterns by combining the fundamental vibration modes of a cylindrical acoustic radiator. This allows the transducer to be electrically controlled and steered by simply adjusting the electrical voltage weights. A prototype acoustic modem is then developed to utilize the multimodal directional transducer for both LOS and NLOS communication. The acoustic modem has also been used as a platform for empirically validating our SBR communication model in a tank and with empirical data. Networking protocols have been developed to exploit the SBR communication model. These protocols include node discovery and localization, directional medium access control (D-MAC) and geographical routing. In node discovery and localization, each node will utilize SBR-based range measurements to its neighbors to determine their relative position. The D-MAC protocol utilizes directional antennas to increase the network throughput due to the spatial efficiency of the antenna model. In the proposed reflection-enabled directional MAC protocol (RED-MAC), each source node will be able to determine if an obstacle is blocking the LOS link to the destination and switch to the best NLOS link by utilizing surface/bottom reflections. Finally, we have developed a geographical routing algorithm which aims to establish the best stable route from a source node to a destination node. The optimized route is selected to achieve maximum network throughput. Extensive analysis of the network throughput when utilizing directional antennas is also presented

  13. Computational analysis of acoustic transmission through periodically perforated interfaces

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    Rohan E.


    Full Text Available The objective of the paper is to demonstrate the homogenization approach applied to modelling the acoustic transmission on perforated interfaces embedded in the acoustic fluid. We assume a layer, with periodically perforated obstacles, separating two half-spaces filled with the fluid. The homogenization method provides limit transmission conditions which can be prescribed at the homogenized surface representing the "limit" interface. The conditions describe relationship between jump of the acoustic pressures and the transversal acoustic velocity, on introducing the "in-layer pressure" which describes wave propagation in the tangent directions with respect to the interface.This approach may serve as a relevant tool for optimal design of devices aimed at attenuation of the acoustic waves, such as the engine exhaust mufflers or other structures fitted with sieves and grillages. We present numerical examples of wave propagation in a muffler-like structure illustrating viability of the approach when complex 3D geometries of the interface perforation are considered.

  14. GLider Acoustics Sensing of Sediments (GLASS): Experiments and Data Analysis (United States)


    on different types of seabeds will be performed during the REP14-MED experiment planned in June 2014. • Eventually, equip a SLOCUM glider with a longer... GLider Acoustics Sensing of Sediments (GLASS): experiments and data analysis Peter L. Nielsen December 2013 About CMRE The...document. CMRE–FR-2013-025 GLider Acoustics Sensing of Sediments (GLASS): Experiments and data analysis Peter L. Nielsen, Lanfranco Muzi, Martin

  15. Application of cochlear analysis techniques to percussion in electro-acoustic music (United States)

    Mills, John


    This presentation is focused upon the audio analysis involved in the creation of a ``pseudo-score'' for electro-acoustic music. This research was undertaken because the lack of an objective visual representation prevents music theorists from being able to easily discuss electro-acoustic music in written form. The ``holy grail'' of automatic computer music analysis has most often been the translation of a continuous pressure variation into traditional Western musical notation. Since electro-acoustic music is rarely able to be transcribed into this type of notation, the automatic analysis of electro-acoustic music confounds many previous algorithms. A top-down approach is suggested in order to extract acoustic and musical information from recordings of electro-acoustic music. Because humans are the best known system for translating a continuous pressure variation into useful acoustic information, a cochlear model, Patterson's Auditory Image Model (AIM), is used as a front end. The audio property of self-similarity of percussion has been chosen for initial study. This self-similarity property requires first that the audio property of percussion is quantified. The nuances of using AIM to determine percussion will be discussed. Models of self-similarity of percussion for varying time-scales will then be discussed.

  16. Spatio-Temporal Analysis of Urban Acoustic Environments with Binaural Psycho-Acoustical Considerations for IoT-Based Applications. (United States)

    Segura-Garcia, Jaume; Navarro-Ruiz, Juan Miguel; Perez-Solano, Juan J; Montoya-Belmonte, Jose; Felici-Castell, Santiago; Cobos, Maximo; Torres-Aranda, Ana M


    Sound pleasantness or annoyance perceived in urban soundscapes is a major concern in environmental acoustics. Binaural psychoacoustic parameters are helpful to describe generic acoustic environments, as it is stated within the ISO 12913 framework. In this paper, the application of a Wireless Acoustic Sensor Network (WASN) to evaluate the spatial distribution and the evolution of urban acoustic environments is described. Two experiments are presented using an indoor and an outdoor deployment of a WASN with several nodes using an Internet of Things (IoT) environment to collect audio data and calculate meaningful parameters such as the sound pressure level, binaural loudness and binaural sharpness. A chunk of audio is recorded in each node periodically with a microphone array and the binaural rendering is conducted by exploiting the estimated directional characteristics of the incoming sound by means of DOA estimation. Each node computes the parameters in a different location and sends the values to a cloud-based broker structure that allows spatial statistical analysis through Kriging techniques. A cross-validation analysis is also performed to confirm the usefulness of the proposed system.

  17. Attenuation Analysis and Acoustic Pressure Levels for Combined Absorptive Mufflers

    Directory of Open Access Journals (Sweden)

    Ovidiu Vasile


    Full Text Available The paper describes the pressure-wave propagation in a muffler for an internal combustion engine in case of two combined mufflers geometry. The approach is generally applicable to analyzing the damping of propagation of harmonic pressure waves. The paper purpose is to show finite elements analysis of both inductive and resistive damping in pressure acoustics. The main output is the attenuation and acoustic pressure levels for the frequency range 50 Hz–3000 Hz.

  18. DARHT Multi-intelligence Seismic and Acoustic Data Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Garrison Nicole [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Van Buren, Kendra Lu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The purpose of this report is to document the analysis of seismic and acoustic data collected at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory for robust, multi-intelligence decision making. The data utilized herein is obtained from two tri-axial seismic sensors and three acoustic sensors, resulting in a total of nine data channels. The goal of this analysis is to develop a generalized, automated framework to determine internal operations at DARHT using informative features extracted from measurements collected external of the facility. Our framework involves four components: (1) feature extraction, (2) data fusion, (3) classification, and finally (4) robustness analysis. Two approaches are taken for extracting features from the data. The first of these, generic feature extraction, involves extraction of statistical features from the nine data channels. The second approach, event detection, identifies specific events relevant to traffic entering and leaving the facility as well as explosive activities at DARHT and nearby explosive testing sites. Event detection is completed using a two stage method, first utilizing signatures in the frequency domain to identify outliers and second extracting short duration events of interest among these outliers by evaluating residuals of an autoregressive exogenous time series model. Features extracted from each data set are then fused to perform analysis with a multi-intelligence paradigm, where information from multiple data sets are combined to generate more information than available through analysis of each independently. The fused feature set is used to train a statistical classifier and predict the state of operations to inform a decision maker. We demonstrate this classification using both generic statistical features and event detection and provide a comparison of the two methods. Finally, the concept of decision robustness is presented through a preliminary analysis where

  19. Analysis of Vibration and Acoustic Noise in Permanent Magnet Motors. (United States)

    Hwang, Sangmoon

    The drive motor is a frequent source of vibration and acoustic noise in many precision spindle motors. One of the electromagnetic sources of vibration in permanent magnet motors is the torque ripple, consisting of the reluctance torque and electromagnetic torque fluctuation. This type of vibration is becoming more serious with the advent of new high-grade magnets with increased flux density. Acoustic noise of electromagnetic origin is difficult to predict and its exact mechanism is unclear. The mechanism of noise generation should be revealed to design a quieter motor which is the modern customer's demand. For motor operation at low speeds and loads, torque ripple due to the reluctance torque is often a source of vibration and control difficulty. The reluctance torque in a motor was calculated from the flux density by a finite element method and the Maxwell stress method. Effects of design parameters, such as stator slot width, permanent slot width, airgap length and magnetization direction, were investigated. Magnet pole shaping, by gradually decreasing the magnet thickness toward edges, yields a sinusoidal shape of the reluctance torque with reduced harmonics, thus reducing the vibration. This dissertation also presents two motor design techniques: stator tooth notching and rotor pole skewing with magnet pole shaping, and the effect of each method on the output torque. The analysis shows that the reluctance torque can be nearly eliminated by the suggested designs, with minimal sacrifice of the output torque. In permanent magnet DC motors, the most popular design type is the trapezoidal back electro-motive force (BEMF), for switched DC controllers. It is demonstrated that the output torque profile of one phase energized is qualitatively equivalent to the BEMF profile for motors with reduced reluctance torque. It implies that design of BEMF profile is possible by magnetic modeling of a motor, without expensive and time-consuming experiments for different designs

  20. Effect of stimuli presentation method on perception of room size using only acoustic cues (United States)

    Hunt, Jeffrey Barnabas

    People listen to music and speech in a large variety of rooms and many room parameters, including the size of the room, can drastically affect how well the speech is understood or the music enjoyed. While multi-modal (typically hearing and sight) tests may be more realistic, in order to isolate what acoustic cues listeners use to determine the size of a room, a listening-only tests is conducted here. Nearly all of the studies to-date on the perception of room volume using acoustic cues have presented the stimuli only over headphones and these studies have reported that, in most cases, the perceived room volume is more highly correlated with the perceived reverberation (reverberance) than with actual room volume. While reverberance may be a salient acoustic cue used for the determination or room size, the actual sound field in a room is not accurately reproduced when presented over headphones and it is thought that some of the complexities of the sound field that relate to perception of geometric volume, specifically directional information of reflections, may be lost. It is possible that the importance of reverberance may be overemphasized when using only headphones to present stimuli so a comparison of room-size perception is proposed where the sound field (from modeled and recorded impulse responses) is presented both over headphones and also over a surround system using higher order ambisonics to more accurately produce directional sound information. Major results are that, in this study, no difference could be seen between the two presentation methods and that reverberation time is highly correlated to room-size perception while real room size is not.

  1. Functional analysis of voice using simultaneous high-speed imaging and acoustic recordings. (United States)

    Yan, Yuling; Damrose, Edward; Bless, Diane


    We present a comprehensive, functional analysis of clinical voice data derived from both high-speed digital imaging (HSDI) of the larynx and simultaneously acquired acoustic recordings. The goals of this study are to: (1) correlate dynamic characteristics of the vocal folds derived from direct laryngeal imaging with indirectly acquired acoustic measurements; (2) define the advantages of using a combined imaging/acoustic approach for the analysis of voice condition; and (3) identify new quantitative measures to evaluate the regularity of the vocal fold vibration and the complexity of the vocal output -- these measures will be key to successful diagnosis of vocal abnormalities. Image- and acoustic-based analyses are performed using an analytic phase plot approach previously introduced by our group (referred to as 'Nyquist' plot). Fast Fourier Transform (FFT) spectral analyses are performed on the same data for a comparison. Clinical HSDI and acoustic recordings from subjects having normal and specific voice pathologies, including muscular tension dysphonia (MTD) and recurrent respiratory papillomatosis (RRP) were analyzed using the Nyquist plot approach. The results of these analyses show that a combined imaging/acoustic analysis approach provides better characterization of the vibratory behavior of the vocal folds as it correlates with vocal output and pathology.

  2. A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data

    Energy Technology Data Exchange (ETDEWEB)



    Aerospace payloads, such as satellites, are subjected to vibroacoustic excitation during launch. Sandia's MTI satellite has recently been certified to this environment using a combination of base input random vibration and reverberant acoustic noise. The initial choices for the acoustic and random vibration test specifications were obtained from the launch vehicle Interface Control Document (ICD). In order to tailor the random vibration levels for the laboratory certification testing, it was necessary to determine whether vibration energy was flowing across the launch vehicle interface from the satellite to the launch vehicle or the other direction. For frequencies below 120 Hz this issue was addressed using response limiting techniques based on results from the Coupled Loads Analysis (CLA). However, since the CLA Finite Element Analysis FEA model was only correlated for frequencies below 120 Hz, Statistical Energy Analysis (SEA) was considered to be a better choice for predicting the direction of the energy flow for frequencies above 120 Hz. The existing SEA model of the launch vehicle had been developed using the VibroAcoustic Payload Environment Prediction System (VAPEPS) computer code [1]. Therefore, the satellite would have to be modeled using VAPEPS as well. As is the case for any computational model, the confidence in its predictive capability increases if one can correlate a sample prediction against experimental data. Fortunately, Sandia had the ideal data set for correlating an SEA model of the MTI satellite--the measured response of a realistic assembly to a reverberant acoustic test that was performed during MTI's qualification test series. The first part of this paper will briefly describe the VAPEPS modeling effort and present the results of the correlation study for the VAPEPS model. The second part of this paper will present the results from a study that used a commercial SEA software package [2] to study the effects of in-plane modes and

  3. Isogeometric finite element analysis of time-harmonic exterior acoustic scattering problems

    CERN Document Server

    Khajah, Tahsin; Bordas, Stéphane P A


    We present an isogeometric analysis of time-harmonic exterior acoustic problems. The infinite space is truncated by a fictitious boundary and (simple) absorbing boundary conditions are applied. The truncation error is included in the exact solution so that the reported error is an indicator of the performance of the isogeometric analysis, in particular of the related pollution error. Numerical results performed with high-order basis functions (third or fourth orders) showed no visible pollution error even for very high frequencies. This property combined with exact geometrical representation makes isogeometric analysis a very promising platform to solve high-frequency acoustic problems.

  4. A Phonemic and Acoustic Analysis of Hindko Oral Stops

    Directory of Open Access Journals (Sweden)

    Haroon Ur RASHID


    Full Text Available Hindko is an Indo-Aryan language that is mainly spoken in Khyber Pukhtoonkhaw province of Pakistan. This work aims to identify the oral stops of Hindko and determine the intrinsic acoustic cues for them. The phonemic analysis is done with the help of minimal pairs and phoneme distribution in contrastive environments which reveals that Hindko has twelve oral stops with three way series. The acoustic analysis of these segments shows that intrinsically voice onset time (VOT, closure duration and burst are reliable and distinguishing cues of stops in Hindko.

  5. Nested sampling applied in Bayesian room-acoustics decay analysis. (United States)

    Jasa, Tomislav; Xiang, Ning


    Room-acoustic energy decays often exhibit single-rate or multiple-rate characteristics in a wide variety of rooms/halls. Both the energy decay order and decay parameter estimation are of practical significance in architectural acoustics applications, representing two different levels of Bayesian probabilistic inference. This paper discusses a model-based sound energy decay analysis within a Bayesian framework utilizing the nested sampling algorithm. The nested sampling algorithm is specifically developed to evaluate the Bayesian evidence required for determining the energy decay order with decay parameter estimates as a secondary result. Taking the energy decay analysis in architectural acoustics as an example, this paper demonstrates that two different levels of inference, decay model-selection and decay parameter estimation, can be cohesively accomplished by the nested sampling algorithm.

  6. Acoustic analysis in Mudejar-Gothic churches: Experimental results (United States)

    Galindo, Miguel; Zamarreño, Teófilo; Girón, Sara


    This paper describes the preliminary results of research work in acoustics, conducted in a set of 12 Mudejar-Gothic churches in the city of Seville in the south of Spain. Despite common architectural style, the churches feature individual characteristics and have volumes ranging from 3947 to 10 708 m3. Acoustic parameters were measured in unoccupied churches according to the ISO-3382 standard. An extensive experimental study was carried out using impulse response analysis through a maximum length sequence measurement system in each church. It covered aspects such as reverberation (reverberation times, early decay times), distribution of sound levels (sound strength); early to late sound energy parameters derived from the impulse responses (center time, clarity for speech, clarity, definition, lateral energy fraction), and speech intelligibility (rapid speech transmission index), which all take both spectral and spatial distribution into account. Background noise was also measured to obtain the NR indices. The study describes the acoustic field inside each temple and establishes a discussion for each one of the acoustic descriptors mentioned by using the theoretical models available and the principles of architectural acoustics. Analysis of the quality of the spaces for music and speech is carried out according to the most widespread criteria for auditoria. .

  7. Acoustic analysis in Mudejar-Gothic churches: experimental results. (United States)

    Galindo, Miguel; Zamarreño, Teófilo; Girón, Sara


    This paper describes the preliminary results of research work in acoustics, conducted in a set of 12 Mudejar-Gothic churches in the city of Seville in the south of Spain. Despite common architectural style, the churches feature individual characteristics and have volumes ranging from 3947 to 10 708 m3. Acoustic parameters were measured in unoccupied churches according to the ISO-3382 standard. An extensive experimental study was carried out using impulse response analysis through a maximum length sequence measurement system in each church. It covered aspects such as reverberation (reverberation times, early decay times), distribution of sound levels (sound strength); early to late sound energy parameters derived from the impulse responses (center time, clarity for speech, clarity, definition, lateral energy fraction), and speech intelligibility (rapid speech transmission index), which all take both spectral and spatial distribution into account. Background noise was also measured to obtain the NR indices. The study describes the acoustic field inside each temple and establishes a discussion for each one of the acoustic descriptors mentioned by using the theoretical models available and the principles of architectural acoustics. Analysis of the quality of the spaces for music and speech is carried out according to the most widespread criteria for auditoria.

  8. Acoustic Analysis of Nasal Vowels in Monguor Language (United States)

    Zhang, Hanbin


    The purpose of the study is to analyze the spectrum characteristics and acoustic features for the nasal vowels [ɑ˜] and [ɔ˜] in Monguor language. On the base of acoustic parameter database of the Monguor speech, the study finds out that there are five main zero-pole pairs appearing for the nasal vowel [ɔ˜] and two zero-pole pairs appear for the nasal vowel [ɔ˜]. The results of regression analysis demonstrate that the duration of the nasal vowel [ɔ˜] or the nasal vowel [ɔ˜] can be predicted by its F1, F2 and F3 respectively.

  9. Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Dickow, Kristoffer Ahrens; Andersen, Lars Vabbersgaard


    in such buildings is important. In the lowfrequency range, prediction of sound and vibration in building structures may be achieved by finite-element analysis (FEA). The aim of this paper is to compare the two commercial codes ABAQUS and ANSYS for FEA of an acoustic-structural coupling in a timber lightweight panel...

  10. Acoustic analysis of primate air sacs and their effect on vocalization

    NARCIS (Netherlands)

    de Boer, B.


    This paper presents an analysis of the acoustic impedance of primate air sacs and their interaction with the vocal tract. A lumped element model is derived and it is found that the inertance of the neck and the volume of the air sac are relevant, as well as the mass and stiffness of the walls

  11. Acoustical contribution calculation and analysis of compressor shell based on acoustic transfer vector method (United States)

    Chen, Xiaol; Guo, Bei; Tuo, Jinliang; Zhou, Ruixin; Lu, Yang


    Nowadays, people are paying more and more attention to the noise reduction of household refrigerator compressor. This paper established a sound field bounded by compressor shell and ISO3744 standard field points. The Acoustic Transfer Vector (ATV) in the sound field radiated by a refrigerator compressor shell were calculated which fits the test result preferably. Then the compressor shell surface is divided into several parts. Based on Acoustic Transfer Vector approach, the sound pressure contribution to the field points and the sound power contribution to the sound field of each part were calculated. To obtain the noise radiation in the sound field, the sound pressure cloud charts were analyzed, and the contribution curves in different frequency of each part were acquired. Meanwhile, the sound power contribution of each part in different frequency was analyzed, to ensure those parts where contributes larger sound power. Through the analysis of acoustic contribution, those parts where radiate larger noise on the compressor shell were determined. This paper provides a credible and effective approach on the structure optimal design of refrigerator compressor shell, which is meaningful in the noise and vibration reduction.

  12. Acoustic Emission Analysis of Prestressed Concrete Structures (United States)

    Elfergani, H. A.; Pullin, R.; Holford, K. M.


    Corrosion is a substantial problem in numerous structures and in particular corrosion is very serious in reinforced and prestressed concrete and must, in certain applications, be given special consideration because failure may result in loss of life and high financial cost. Furthermore corrosion cannot only be considered a long term problem with many studies reporting failure of bridges and concrete pipes due to corrosion within a short period after they were constructed. The concrete pipes which transport water are examples of structures that have suffered from corrosion; for example, the pipes of The Great Man-Made River Project of Libya. Five pipe failures due to corrosion have occurred since their installation. The main reason for the damage is corrosion of prestressed wires in the pipes due to the attack of chloride ions from the surrounding soil. Detection of the corrosion in initial stages has been very important to avoid other failures and the interruption of water flow. Even though most non-destructive methods which are used in the project are able to detect wire breaks, they cannot detect the presence of corrosion. Hence in areas where no excavation has been completed, areas of serious damage can go undetected. Therefore, the major problem which faces engineers is to find the best way to detect the corrosion and prevent the pipes from deteriorating. This paper reports on the use of the Acoustic Emission (AE) technique to detect the early stages of corrosion prior to deterioration of concrete structures.

  13. Structural-acoustic finite element analysis of the automobile passenger compartment: A review of current practice (United States)

    Nefske, D. J.; Wolf, J. A.; Howell, L. J.


    This paper contains a brief review of the formulation of the finite element method for structural-acoustic analysis of an enclosed cavity, and illustrations are given of the application of this analytical method at General Motors Corporation to investigate the acoustics of the automobile passenger compartment. Low frequency noise in the passenger compartment (in approximately the 20-200 Hz frequency range) is of primary interest, and particularly that noise which is generated by the structural vibration of the wall panels of the compartment. The topics which are covered in the paper include the computation of acoustic modes and resonant frequencies of the passenger compartment, the effect of flexible wall panels on the cavity acoustics, the methods of direct and modal coupling of the structural and acoustic vehicle systems, and forced vibration analysis illustrating the techniques for computing panel-excited noise and for identifying critical panels around the passenger compartment. The capabilities of the finite element method are illustrated by applications to the production automobile, and experimental verifications of the various techniques are presented to illustrate the accuracy of the method.

  14. A novel method for perceptual assessment of small room acoustics using rapid sensory analysis

    DEFF Research Database (Denmark)

    Kaplanis, Neofytos; Bech, Søren; Lokki, Tapio


    small rooms and car cabins. In-situ measurements were performed to obtain a range of possible acoustical settings, by varying physically the spaces under investigation. The measured responses were spatiallyanalyzed and synthesized to reproduce the observed fields in the laboratory. Expert listeners were...... presented with auralized sound over a loudspeaker array and followed a rapid sensory analysis protocol. The elicited attributes and ratings are analyzed and possible links to the acoustical properties of these spaces are discussed. [This study is a part of Marie Curie Network on Dereverberation...

  15. Correlation analysis between ceramic insulator pollution and acoustic emissions

    Directory of Open Access Journals (Sweden)

    Benjamín Álvarez-Nasrallah


    Full Text Available Most of the studies related to insulator pollution are normally performed based on individual analysis among leakage current, relative humidity and equivalent salt deposit density (ESDD. This paper presents a correlation analysis between the leakage current and the acoustic emissions measured in a 230 kV electrical substations in the city of Barranquilla, Colombia. Furthermore, atmospheric variables were considered to develop a characterization model of the insulator contamination process. This model was used to demonstrate that noise emission levels are a reliable indicator to detect and characterize pollution on high voltage insulators. The correlation found amount the atmospheric, electrical and sound variables allowed to determine the relations for the maintenance of ceramic insulators in high-polluted areas. In this article, the results on the behavior of the leakage current in ceramic insulators and the sound produced with different atmospheric conditions are shown, which allow evaluating the best time to clean the insulator at the substation. Furthermore, by experimentation on site and using statistical models, the correlation between ambient variables and the leakage current of insulators in an electrical substation was obtained. Some of the problems that bring the external noise were overcome using multiple microphones and specialized software that enabled properly filter the sound and better measure the variables.

  16. Dynamic Analysis of the Titanium Alloy Plate under Thermal-acoustic Loadings

    Directory of Open Access Journals (Sweden)

    Zou Xuefeng


    Full Text Available Hypersonic vehicles structures suffer complex combined loadings generally. For the thin-walled structures and thermal protection systems of the aircraft, high temperature and intensity acoustic loadings are the significant factors that leading to their break. The object of this paper is typical simply supported titanium alloy plate, the finite element method was adopted to calculate the critical thermal buckling temperature the ordinal coupling method and Newmark method were adopted to calculate the thermal-acoustic dynamic response. Based on the FEM analysis, the power spectrum densities (PSD of center point was presented. Research results show that the thermal buckling of the typical simply supported titanium alloy plate occurs easily because of the low critical thermal buckling temperature, dynamic response of the thermal buckled plate suffering acoustic loads performs strong nonlinear characteristics and complex forms of exercise.

  17. MOCHA: Multi-Study Ocean Acoustics Human Effects Analysis (United States)


    looking at other odontocetes ( killer whales , Risso’s dolphins, false killer whale , melon- headed whale ) and are now beginning to focus on pilot whales ...ranging killer whales . Journal of the Acoustical Society of America. [submitted] Southall, B.L., Moretti, D.J., Abraham, B., Calambokidis, J., DeRuiter...OBJECTIVES The overall objective of this project is to develop and implement innovative statistical methodologies for the analysis of behavioral

  18. Parallel Finite Element Domain Decomposition for Structural/Acoustic Analysis (United States)

    Nguyen, Duc T.; Tungkahotara, Siroj; Watson, Willie R.; Rajan, Subramaniam D.


    A domain decomposition (DD) formulation for solving sparse linear systems of equations resulting from finite element analysis is presented. The formulation incorporates mixed direct and iterative equation solving strategics and other novel algorithmic ideas that are optimized to take advantage of sparsity and exploit modern computer architecture, such as memory and parallel computing. The most time consuming part of the formulation is identified and the critical roles of direct sparse and iterative solvers within the framework of the formulation are discussed. Experiments on several computer platforms using several complex test matrices are conducted using software based on the formulation. Small-scale structural examples are used to validate thc steps in the formulation and large-scale (l,000,000+ unknowns) duct acoustic examples are used to evaluate the ORIGIN 2000 processors, and a duster of 6 PCs (running under the Windows environment). Statistics show that the formulation is efficient in both sequential and parallel computing environmental and that the formulation is significantly faster and consumes less memory than that based on one of the best available commercialized parallel sparse solvers.

  19. Acoustic emission intensity analysis of corrosion in prestressed concrete piles (United States)

    Vélez, William; Matta, Fabio; Ziehl, Paul


    Corrosion of steel strands in prestressed concrete (PC) bridges may lead to substantial damage or collapse well before the end of the design life. Acoustic Emission (AE) is a suitable nondestructive technique to detect and locate corrosion in reinforced and prestressed concrete, which is key to prioritize inspection and maintenance. An effective tool to analyze damage-related AE data is intensity analysis (IA), which is based on two data trends, namely Severity (average signal strength of high amplitude hits) and Historic Index (ratio of the average signal strength of the most recent hits to the average of all hits). IA criteria for corrosion assessment in PC were recently proposed based on empirical evidence from accelerated corrosion tests. In this paper, AE data from prestressed and non-prestressed concrete pile specimens exposed to salt water wet-dry cycling for over 600 days are used to analyze the relation between Severity and Historic Index and actual corrosion. Evidence of corrosion is gained from the inspection of decommissioned specimens. The selection of suitable J and K parameters for IA is discussed, and an IA chart with updated corrosion criteria for PC piles is presented.

  20. Acoustical Imaging

    CERN Document Server

    Akiyama, Iwaki


    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...

  1. Analysis of enhanced modal damping ratio in porous materials using an acoustic-structure interaction model

    DEFF Research Database (Denmark)

    Kook, Junghwan; Jensen, Jakob Søndergaard


    relation expressing how an increased damping due to the acoustic medium surrounding the microbeam affect the MDR of the macrobeam. We further analyze the effect of including dissipation of the acoustic medium by using finite element (FE) analysis with acoustic-structure interaction (ASI) using a simple...

  2. Quantified elasticity mapping of ocular tissue using acoustic radiation force optical coherence elastography (Conference Presentation) (United States)

    Qu, Yueqiao; He, Youmin; Zhang, Yi; Ma, Teng; Zhu, Jiang; Miao, Yusi; Dai, Cuixia; Silverman, Ronald; Humayun, Mark S.; Zhou, Qifa; Chen, Zhongping


    Age-related macular degeneration and keratoconus are two ocular diseases occurring in the posterior and anterior eye, respectively. In both conditions, the mechanical elasticity of the respective tissues changes during the early onset of disease. It is necessary to detect these differences and treat the diseases in their early stages to provide proper treatment. Acoustic radiation force optical coherence elastography is a method of elasticity mapping using confocal ultrasound waves for excitation and Doppler optical coherence tomography for detection. We report on an ARF-OCE system that uses modulated compression wave based excitation signals, and detects the spatial and frequency responses of the tissue. First, all components of the system is synchronized and triggered such that the signal is consistent between frames. Next, phantom studies are performed to validate and calibrate the relationship between the resonance frequency and the Young's modulus. Then the frequency responses of the anterior and posterior eye are detected for porcine and rabbit eyes, and the results correlated to the elasticity. Finally, spatial elastograms are obtained for a porcine retina. Layer segmentation and analysis is performed and correlated to the histology of the retina, where five distinct layers are recognized. The elasticities of the tissue layers will be quantified according to the mean thickness and displacement response for the locations on the retina. This study is a stepping stone to future in-vivo animal studies, where the elastic modulus of the ocular tissue can be quantified and mapped out accordingly.

  3. Differential diagnosis between apraxia and dysarthria based on acoustic analysis. (United States)

    Melle, Natalia; Gallego, Carlos


    Acoustic analysis provides objective quantitative measures of speech that enable a comprehensive and accurate understanding of motor disorders and complement the traditional measures. This paper aims to distinguish between normal and pathological speech, more specifically between apraxia of speech and spastic dysarthria in native Spanish speaking patients using acoustic parameters. Participants (4 aphasic with apraxia of speech, 4 with spastic dysarthria, and 15 without speech disorders) performed three different tasks: repeating the syllable sequence [pa-ta-ka], repeating the isolated syllable [pa] and repeating the vowel sequence [i-u]. The results showed that the normative values of motor control, in general, coincide with those obtained in previous research on native English speakers. They also show that damage to motor control processes results in a decrease in the rate of alternating and sequential movements and an increase in the inter-syllabic time for both types of movements. A subset of the acoustic parameters analyzed, those that measure motor planning processes, enable differentiation between normal population and apraxic and dysarthric patients, and between the latter. The differences between the pathological groups support the distinction between motor planning and motor programming as described by van der Merwe's model of sensorimotor processing (1997).

  4. Analysis of acoustic emission waveforms from fatigue cracks (United States)

    Bhuiyan, Md. Yeasin; Bao, Jingjing; Poddar, Banibrata; Giurgiutiu, Victor


    Acoustic emission (AE) monitoring technique is a well-known approach in the field of NDE/SHM. AE monitoring from the defect formation and failure in the materials were well studied by the researchers. However, conventional AE monitoring techniques are predominantly based on statistical analysis. In this study we focus on understanding the AE waveforms from the fatigue crack growth using physics based approach. The growth of the fatigue crack causes the acoustic emission in the material that propagates in the structure. One of the main challenges of this approach is to develop the physics based understanding of the AE source itself. The acoustic emission happens not only from the crack growth but also from the interaction of the crack lips during fatigue loading of the materials. As the waveforms are generated from the AE event, they propagate and create local vibration modes along the crack faces. Fatigue experiments were performed to generate the fatigue cracks. Several test specimens were used in the fatigue experiments and corresponding AE waveforms were captured. The AE waveforms were analyzed and distinguished into different groups based on the similar nature on both time domain and frequency domain. The experimental results are explained based on the physical observation of the specimen.

  5. Acoustic analysis of pathological voices compressed with MPEG system. (United States)

    Gonzalez, Julio; Cervera, Teresa; Llau, M José


    The MPEG-1 Layer 3 compression schema of audio signal, commonly known as mp3, has caused a great impact in recent years as it has reached high compression rates while conserving a high sound quality. Music and speech samples compressed at high bitrates are perceptually indistinguishable from the original samples, but very little was known about how compression acoustically affects the voice signal. A previous work with normal voices showed a high fidelity at high-bitrate compressions both in voice parameters and the amplitude-frequency spectrum. In the present work, dysphonic voices were tested through two studies. In the first study, spectrograms, long-term average spectra (LTAS), and fast Fourier transform (FFT) spectra of compressed and original samples of running speech were compared. In the second study, intensities, formant frequencies, formant bandwidths, and a multidimensional set of voice parameters were tested in a set of sustained phonations. Results showed that compression at high bitrates (96 and 128 kbps) preserved the relevant acoustic properties of the pathological voices. With compressions at lower bitrates, fidelity decreases, introducing some important alterations. Results from both works, Gonzalez and Cervera and this paper, open up the possibility of using MPEG-compression at high bitrates to store or transmit high-quality speech recordings, without altering their acoustic properties.

  6. Machine Fault Detection Based on Filter Bank Similarity Features Using Acoustic and Vibration Analysis

    Directory of Open Access Journals (Sweden)

    Mauricio Holguín-Londoño


    Full Text Available Vibration and acoustic analysis actively support the nondestructive and noninvasive fault diagnostics of rotating machines at early stages. Nonetheless, the acoustic signal is less used because of its vulnerability to external interferences, hindering an efficient and robust analysis for condition monitoring (CM. This paper presents a novel methodology to characterize different failure signatures from rotating machines using either acoustic or vibration signals. Firstly, the signal is decomposed into several narrow-band spectral components applying different filter bank methods such as empirical mode decomposition, wavelet packet transform, and Fourier-based filtering. Secondly, a feature set is built using a proposed similarity measure termed cumulative spectral density index and used to estimate the mutual statistical dependence between each bandwidth-limited component and the raw signal. Finally, a classification scheme is carried out to distinguish the different types of faults. The methodology is tested in two laboratory experiments, including turbine blade degradation and rolling element bearing faults. The robustness of our approach is validated contaminating the signal with several levels of additive white Gaussian noise, obtaining high-performance outcomes that make the usage of vibration, acoustic, and vibroacoustic measurements in different applications comparable. As a result, the proposed fault detection based on filter bank similarity features is a promising methodology to implement in CM of rotating machinery, even using measurements with low signal-to-noise ratio.

  7. A Gene-Based Analysis of Acoustic Startle Latency. (United States)

    Smith, Alicia K; Jovanovic, Tanja; Kilaru, Varun; Lori, Adriana; Gensler, Lauren; Lee, Samuel S; Norrholm, Seth Davin; Massa, Nicholas; Cuthbert, Bruce; Bradley, Bekh; Ressler, Kerry J; Duncan, Erica


    Latency of the acoustic startle response is the time required from the presentation of startling auditory stimulus until the startle response is elicited and provides an index of neural processing speed. Latency is prolonged in subjects with schizophrenia compared to controls in some but not all studies and is 68-90% heritable in baseline startle trials. In order to determine the genetic association with latency as a potential inroad into genetically based vulnerability to psychosis, we conducted a gene-based study of latency followed by an independent replication study of significant gene findings with a single-nucleotide polymorphism (SNP)-based analysis of schizophrenia and control subjects. 313 subjects from an urban population of low socioeconomic status with mixed psychiatric diagnoses were included in the gene-based study. Startle testing was conducted using a Biopac M150 system according to our published methods. Genotyping was performed with the Omni-Quad 1M or the Omni Express BeadChip. The replication study was conducted on 154 schizophrenia subjects and 123 psychiatric controls. Genetic analyses were conducted with Illumina Human Omni1-Quad and OmniExpress BeadChips. Twenty-nine SNPs were selected from four genes that were significant in the gene-based analysis and also associated with startle and/or schizophrenia in the literature. Linear regressions on latency were conducted, controlling for age, race, and diagnosis as a dichotomous variable. In the gene-based study, 2,870 genes demonstrated the evidence of association after correction for multiple comparisons (false discovery rate < 0.05). Pathway analysis of these genes revealed enrichment for relevant biological processes including neural transmission (p = 0.0029), synaptic transmission (p = 0.0032), and neuronal development (p = 0.024). The subsequent SNP-based replication analysis revealed a strong association of onset latency with the SNP rs901561 on the neuregulin gene (NRG1) in

  8. A simple formula for insertion loss prediction of large acoustical enclosures using statistical energy analysis method

    Directory of Open Access Journals (Sweden)

    Kim Hyun-Sil


    Full Text Available Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.


    Directory of Open Access Journals (Sweden)

    Miroslav Neslušan


    Full Text Available The paper deals with analysis of chip formation and related aspects of the chip formation during turning hardened steel 100Cr6. The paper draws a comparison of some aspects of the chip formation between turning annealed and hardened roll bearing steel. The results of the analysis show that there is the formation of a segmented chip in the case of hard turning. Frequency of segmentation is very high. A conventional piezoelectric dynamometer limits the frequency response to about 3.5 kHz. On the other hand, the frequency of process fluctuation may by obtained by using accelerometers or acoustic emission. This paper reports about the dynamic character of cutting process when hard turning and correlation among the calculated segmentation frequencies and the experimental analysis.

  10. Nonlinear acoustic analysis in the evaluation of occupational voice disorders

    Directory of Open Access Journals (Sweden)

    Ewa Niebudek-Bogusz


    Full Text Available Background: Over recent years numerous papers have stressed that production of voice is subjected to the nonlinear processes, which cause aperiodic vibrations of vocal folds. These vibrations cannot always be characterized by means of conventional acoustic parameters, such as measurements of frequency and amplitude perturbations. Thus, special attention has recently been paid to nonlinear acoustic methods. The aim of this study was to assess the applicability of nonlinear cepstral analysis, including the evaluation of mel cepstral coefficients (MFCC, in diagnosing occupational voice disorders. Material and methods: The study involved 275 voice samples of pathologic voice (sustained vowel "a" and four standardized sentences registered in female teachers with the occupation-related benign vocal fold masses (BVFM, such as vocal nodules, polyps, and 200 voice samples of normal voices from the control group of females. The mean age of patients and controls was similar (45 vs. 43 years. Voice samples from both groups were analyzed, including MFCC evaluation. Results: MFCC classification using the Sammon Mapping and Support Vector Machines yielded a considerable accuracy of the test. Voice pathologies were detected in 475 registered voice samples: for vowel "a" with 86% sensitivity and 90% specificity, and for the examined sentences the corresponding values varied between 87% and 100%, respectively. Conclusions: Nonlinear voice analysis with application of mel cepstral coefficients could be a useful and objective tool for confirming occupational-related lesions of the glottis. Further studies addressing this problem are being carried out. Med Pr 2013;64(1:29–35

  11. Experimental and Numerical analysis of Metallic Bellow for Acoustic Performance (United States)

    Panchwadkar, Amit A.; Awasare, Pradeep J., Dr.; Ingle, Ravidra B., Dr.


    Noise will concern about the work environment of industry. Machinery environment has overall noise which interrupts communication between the workers. This problem of miscommunication and health hazard will make sense to go for noise attenuation. Modification in machine setup may affect the performance of it. Instead of that, Helmholtz resonator principle will be a better option for noise reduction along the transmission path. Resonator has design variables which gives resonating frequency will help us to confirm the frequency range. This paper deals with metallic bellow which behaves like inertial mass under incident sound wave. Sound wave energy is affected by hard boundary condition of resonator and bellow. Metallic bellow is used in combination with resonator to find out Transmission loss (TL). Microphone attachment with FFT analyzer will give the frequency range for numerical analysis. Numerical analysis of bellow and resonator is carried out to summarize the acoustic behavior of bellow. Bellow can be numerically analyzed to check noise attenuation for centrifugal blower. An impedance tube measurement technique is performed to validate the numerical results for assembly. Dimensional and shape modification can be done to get the acoustic performance of bellow.

  12. Intelligent acoustic data fusion technique for information security analysis (United States)

    Jiang, Ying; Tang, Yize; Lu, Wenda; Wang, Zhongfeng; Wang, Zepeng; Zhang, Luming


    Tone is an essential component of word formation in all tonal languages, and it plays an important role in the transmission of information in speech communication. Therefore, tones characteristics study can be applied into security analysis of acoustic signal by the means of language identification, etc. In speech processing, fundamental frequency (F0) is often viewed as representing tones by researchers of speech synthesis. However, regular F0 values may lead to low naturalness in synthesized speech. Moreover, F0 and tone are not equivalent linguistically; F0 is just a representation of a tone. Therefore, the Electroglottography (EGG) signal is collected for deeper tones characteristics study. In this paper, focusing on the Northern Kam language, which has nine tonal contours and five level tone types, we first collected EGG and speech signals from six natural male speakers of the Northern Kam language, and then achieved the clustering distributions of the tone curves. After summarizing the main characteristics of tones of Northern Kam, we analyzed the relationship between EGG and speech signal parameters, and laid the foundation for further security analysis of acoustic signal.

  13. Acoustic analysis and mood classification of pain-relieving music. (United States)

    Knox, Don; Beveridge, Scott; Mitchell, Laura A; MacDonald, Raymond A R


    Listening to preferred music (that which is chosen by the participant) has been shown to be effective in mitigating the effects of pain when compared to silence and a variety of distraction techniques. The wide range of genre, tempo, and structure in music chosen by participants in studies utilizing experimentally induced pain has led to the assertion that structure does not play a significant role, rather listening to preferred music renders the music "functionally equivalent" as regards its effect upon pain perception. This study addresses this assumption and performs detailed analysis of a selection of music chosen from three pain studies. Music analysis showed significant correlation between timbral and tonal aspects of music and measurements of pain tolerance and perceived pain intensity. Mood classification was performed using a hierarchical Gaussian Mixture Model, which indicated the majority of the chosen music expressed contentment. The results suggest that in addition to personal preference, associations with music and the listening context, emotion expressed by music, as defined by its acoustical content, is important to enhancing emotional engagement with music and therefore enhances the level of pain reduction and tolerance. © 2011 Acoustical Society of America

  14. Synthesis and analysis of linear and nonlinear acoustical vortices. (United States)

    Marchiano, Régis; Thomas, Jean-Louis


    Acoustical screw dislocations are synthesized in various configurations with a versatile experimental setup. The experimental setup is based on the inverse filter technique and allows one to synthesize one or more acoustical vortices with a chosen width, position, and topological charge. An interesting feature of this experimental facility to study screw dislocation behavior is the direct measurement in amplitude and phase. This characteristic is used to develop an original method of decomposition of an acoustical vortex field in order to analyze the acoustical vortices. Moreover, the behaviors of two acoustical vortices of the same or opposite charge have been studied experimentally and compared to theoretical laws.

  15. North Pacific Acoustic Laboratory: Analysis of Shadow Zone Arrivals and Acoustic Propagation in Numerical Ocean Models

    National Research Council Canada - National Science Library

    Dushaw, Brian


    ... depth of the receiver lies well below the depths of the predicted cusps. Several models for the temperature and salinity in the North Pacific Ocean were obtained and processed to enable simulations of acoustic propagation for comparison to the observations...

  16. Residual Stress Analysis Based on Acoustic and Optical Methods

    Directory of Open Access Journals (Sweden)

    Sanichiro Yoshida


    Full Text Available Co-application of acoustoelasticity and optical interferometry to residual stress analysis is discussed. The underlying idea is to combine the advantages of both methods. Acoustoelasticity is capable of evaluating a residual stress absolutely but it is a single point measurement. Optical interferometry is able to measure deformation yielding two-dimensional, full-field data, but it is not suitable for absolute evaluation of residual stresses. By theoretically relating the deformation data to residual stresses, and calibrating it with absolute residual stress evaluated at a reference point, it is possible to measure residual stresses quantitatively, nondestructively and two-dimensionally. The feasibility of the idea has been tested with a butt-jointed dissimilar plate specimen. A steel plate 18.5 mm wide, 50 mm long and 3.37 mm thick is braze-jointed to a cemented carbide plate of the same dimension along the 18.5 mm-side. Acoustoelasticity evaluates the elastic modulus at reference points via acoustic velocity measurement. A tensile load is applied to the specimen at a constant pulling rate in a stress range substantially lower than the yield stress. Optical interferometry measures the resulting acceleration field. Based on the theory of harmonic oscillation, the acceleration field is correlated to compressive and tensile residual stresses qualitatively. The acoustic and optical results show reasonable agreement in the compressive and tensile residual stresses, indicating the feasibility of the idea.

  17. Analysis of concert hall acoustics via visualizations of time-frequency and spatiotemporal responses. (United States)

    Pätynen, Jukka; Tervo, Sakari; Lokki, Tapio


    Acousticians and other practitioners alike often describe acoustic conditions in performance spaces with standard objective parameters. Apart from a few exceptions, the parameters are calculated by integrating the sound energy of the impulse responses over time; this makes them inadequate for researching the acoustics in detail, especially in the early part of the room impulse response. This paper proposes a method based on time-frequency and spatiotemporal presentations to overcome the lack of detail in the standard analysis. In brief, the proposed methods visualize the cumulative development of the sound field as a function of frequency or direction by forward-integrating the energy in the impulse response in short time frames. Analysis on the measurements from six concert halls concentrates particularly on interpreting the results in light of the seat dip effect. Earlier research has concluded that the seat dip effect is reduced by reflection from low overhead surfaces. In contrast, the current results indicate that the seat dip attenuation in the frequency response is corrected the best when the hall provides most lateral reflections. These findings suggest that the proposed analysis is suitable for explaining concert hall acoustics in detail.

  18. An acoustic analysis of White South African English (WSAfE ...

    African Journals Online (AJOL)

    An acoustic analysis of White South African English (WSAfE) monophthongs. Ian Bekker, Georgina Eley. Abstract. This article has two main aims: (1) to introduce instrumental acoustic techniques to the analysis of the WSAfE accent, and (2), to provide tentative evidence for a new prestige value in the Johannesburg ...

  19. Acoustic analysis of some characteristics of red deer roaring

    Directory of Open Access Journals (Sweden)

    Emanuela Tullo


    Full Text Available Different strategies have been adopted to track and monitor red deer (Cervus elaphus populations according to different habitats and ecosystems. The population census techniques usually carried out are time consuming and involve lot of manpower. A method that relies on individual animal signs like acoustic indices could be useful to support the wildlife management, since vocalisations can encode and transmit a variety of biologically significant information. The present study considered 460 roars recorded from 14 adult deers, from five to eight years old. Recordings were performed in five different locations of northern-central Italy. The acoustic spectrum of each roar was analysed in order to extract its main features, namely: the fundamental frequency (F0, the peak frequency (PF, the sound length (SL and 24 frequency bins of 174.3 Hz, representing the sound distribution between 50 and 4233.2 Hz (F1 to F24. Statistical analyses showed that individuality and age of animals were significant on F0 (P0.90; P<0.001, indicating that age could influence the spectral features of roaring. The roaring frequency variables appear to be indicators of the individuality of male deer, even if the strong influence of age on the emitted sounds could compromise the reliability of the method over long periods of time.

  20. Vibro-acoustics

    CERN Document Server

    Nilsson, Anders


    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...

  1. A comprehensive strategy for the analysis of acoustic compressibility and optical deformability on single cells

    DEFF Research Database (Denmark)

    Yang, Tie; Bragheri, Francesca; Nava, Giovanni


    We realized an integrated microfluidic chip that allows measuring both optical deformability and acoustic compressibility on single cells, by optical stretching and acoustophoresis experiments respectively. Additionally, we propose a measurement protocol that allows evaluating the experimental....... Results indicate that MDA-MB231 has both higher acoustic compressibility and higher optical deformability than MCF7, but statistical analysis shows that optical deformability and acoustic compressibility are not correlated parameters. This result suggests the possibility to use them to analyze...

  2. Statistical Analysis of Acoustic Signal Propagating Through the South China Sea Basin (United States)



  3. Analysis of Acoustic Cavitation Surge in a Rocket Engine Turbopump

    Directory of Open Access Journals (Sweden)

    Hideaki Nanri


    Full Text Available In a liquid rocket engine, cavitation in an inducer of a turbopump sometimes causes instability phenomena when the inducer is operated at low inlet pressure. Cavitation surge (auto-oscillation, one such instability phenomenon, has been discussed mainly based on an inertia model assuming incompressible flow. When this model is used, the frequency of the cavitation surge decreases continuously as the inlet pressure of the turbopump decreases. However, we obtained an interesting experimental result in which the frequency of cavitation surge varied discontinuously. Therefore, we employed one-dimensional analysis based on an acoustic model in which the fluid is assumed to be compressible. The analytical result qualitatively corresponded with the experimental result.

  4. Insertion Loss Analysis of the Acoustic Panels with Composite Construction

    Directory of Open Access Journals (Sweden)

    Vasile Ovidiu


    Full Text Available In order to reduce noise pollution, under European legislation in our country need to align, a special attention has the tests carried out on acoustic panels. The most eloquent attempts, defining traffic noise attenuation are tests that can determine the insertion loss of an acoustic screen. In this paper, it briefly shows the method of determining the insertion loss in octave bands and some real results in the case of acoustic panel in a composite construction.

  5. Acoustic analysis of voice in children with cleft palate and velopharyngeal insufficiency. (United States)

    Villafuerte-Gonzalez, Rocio; Valadez-Jimenez, Victor M; Hernandez-Lopez, Xochiquetzal; Ysunza, Pablo Antonio


    Acoustic analysis of voice can provide instrumental data concerning vocal abnormalities. These findings can be used for monitoring clinical course in cases of voice disorders. Cleft palate severely affects the structure of the vocal tract. Hence, voice quality can also be also affected. To study whether the main acoustic parameters of voice, including fundamental frequency, shimmer and jitter are significantly different in patients with a repaired cleft palate, as compared with normal children without speech, language and voice disorders. Fourteen patients with repaired unilateral cleft lip and palate and persistent or residual velopharyngeal insufficiency (VPI) were studied. A control group was assembled with healthy volunteer subjects matched by age and gender. Hypernasality and nasal emission were perceptually assessed in patients with VPI. Size of the gap as assessed by videonasopharyngoscopy was classified in patients with VPI. Acoustic analysis of voice including Fundamental frequency (F0), shimmer and jitter were compared between patients with VPI and control subjects. F0 was significantly higher in male patients as compared with male controls. Shimmer was significantly higher in patients with VPI regardless of gender. Moreover, patients with moderate VPI showed a significantly higher shimmer perturbation, regardless of gender. Although future research regarding voice disorders in patients with VPI is needed, at the present time it seems reasonable to include strategies for voice therapy in the speech and language pathology intervention plan for patients with VPI. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Health monitoring of Ceramic Matrix Composites from waveform-based analysis of Acoustic Emission

    Directory of Open Access Journals (Sweden)

    Maillet Emmanuel


    Full Text Available Ceramic Matrix Composites (CMCs are anticipated for use in the hot section of aircraft engines. Their implementation requires the understanding of the various damage modes that are involved and their relation to life expectancy. Acoustic Emission (AE has been shown to be an efficient technique for monitoring damage evolution in CMCs. However, only a waveform-based analysis of AE can offer the possibility to validate and precisely examine the recorded AE data with a view to damage localization and identification. The present work fully integrates wave initiation, propagation and acquisition in the analysis of Acoustic Emission waveforms recorded at various sensors, therefore providing more reliable information to assess the relation between Acoustic Emission and damage modes. The procedure allows selecting AE events originating from damage, accurate determination of their location as well as the characterization of effects of propagation on the recorded waveforms. This approach was developed using AE data recorded during tensile tests on carbon/carbon composites. It was then applied to melt-infiltrated SiC/SiC composites.

  7. Informational approach to the analysis of acoustic signals (United States)

    Senkevich, Yuriy; Dyuk, Vyacheslav; Mishchenko, Mikhail; Solodchuk, Alexandra


    The example of linguistic processing of acoustic signals of a seismic event would be an information approach to the processing of non-stationary signals. The method for converting an acoustic signal into an information message is described by identifying repetitive self-similar patterns. The definitions of the event selection indicators in the symbolic recording of the acoustic signal are given. The results of processing an acoustic signal by a computer program realizing the processing of linguistic data are shown. Advantages and disadvantages of using software algorithms are indicated.

  8. Generation and analysis of an acoustic radiation pattern database for forty-one musical instruments. (United States)

    Shabtai, Noam R; Behler, Gottfried; Vorländer, Michael; Weinzierl, Stefan


    A database of acoustic radiation patterns was recorded, modeled, and analyzed for 41 modern or authentic orchestral musical instruments. The generation of this database included recordings of each instrument over the entire chromatic tone range in an anechoic chamber using a surrounding spherical microphone array. Acoustic source centering was applied in order to align the acoustic center of the sound source to the physical center of the microphone array. The acoustic radiation pattern is generated in the spherical harmonics domain at each harmonic partial of each played tone. An analysis of the acoustic radiation pattern complexity has been performed in terms of the number of excitation points using the centering algorithm. The database can be used both for studying the radiation of musical instruments itself, as well as for the implementation of radiation patterns in room acoustical simulations and auralization in order to obtain a spatial excitation of the room closer to reality.

  9. Acoustic analysis of elliptical muffler chamber having a perforated pipe (United States)

    Sohei, Nishimura; Tsuyoshi, Nishimura; Takashi, Yano


    Evidently, a perforated pipe is an essential component in muffler systems. It has the ability to reduce the power levels of noise sources generated by flow. Muffler systems are composed of several elements joined together in series or parallel. In practical approach, each element can have one or more perforated pipe installed. This yields the ability to estimate the acoustic characteristic by the product of the individual element four-pole parameters. In this work, a method to derive the four-pole parameters of such element with consideration of higher-order mode is presented. Based on the results obtained, the parameter C was investigated systematically. Some comparisons between the experimental measurements and the predicted results are discussed. The mean flow velocity is not considered in this paper.

  10. Operational Performance Analysis of Passive Acoustic Monitoring for Killer Whales

    Energy Technology Data Exchange (ETDEWEB)

    Matzner, Shari; Fu, Tao; Ren, Huiying; Deng, Zhiqun; Sun, Yannan; Carlson, Thomas J.


    For the planned tidal turbine site in Puget Sound, WA, the main concern is to protect Southern Resident Killer Whales (SRKW) due to their Endangered Species Act status. A passive acoustic monitoring system is proposed because the whales emit vocalizations that can be detected by a passive system. The algorithm for detection is implemented in two stages. The first stage is an energy detector designed to detect candidate signals. The second stage is a spectral classifier that is designed to reduce false alarms. The evaluation presented here of the detection algorithm incorporates behavioral models of the species of interest, environmental models of noise levels and potential false alarm sources to provide a realistic characterization of expected operational performance.

  11. Present Status and Future of DCC Analysis

    CERN Document Server

    Nayak, Tapank K.; Agnihotri, A.; Ahammed, Z.; Angelis, A.L.S.; Antonenko, V.; Arefev, V.; Astakhov, V.; Avdeichikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Baldine, A.; Barabach, L.; Barlag, C.; Bathe, S.; Batyunya, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bock, R.; Bohne, E.M.; Bucher, D.; Buijs, A.; Buis, E.J.; Busching, H.; Carlen, L.; Chalyshev, V.; Chattopadhyay, S.; Chenawi, K.E.; Cherbachev, R.; Chujo, T.; Claussen, A.; Das, A.C.; Decowski, M.P.; Dzhordzhadze, V.; Donni, P.; Dubovik, I.; Dutta Majumdar, M.R.; Eliseev, S.; Enosawa, K.; Feldmann, H.; Foka, P.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishchuk, O.; Geurts, F.J.M.; Ghosh, T.K.; Glasow, R.; Gupta, S.K.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Higuchi, R.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Kampert, K.H.; Karadzhev, K.; Karpio, K.; Kato, S.; Kees, S.; Kim, H.; Kolb, B.W.; Kosarev, I.; Kucheryaev, I.; Kugler, A.; Kulinich, P.; Kumar, V.; Kurata, M.; Kurita, K.; Kuzmin, N.; Langbein, I.; Lebedev, A.; Lee, Y.Y.; Lohner, H.; Mahapatra, D.P.; Manko, V.; Martin, M.; Maximov, A.; Mehdiyev, Rashid R.; Mgebrichvili, G.; Miake, Y.; Mikhalev, D.; Mishra, G.C.; Miyamoto, Y.; Morrison, Douglas R.O.; Mukhopadhyay, D.S.; Myalkovsky, V.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Neumaier, S.; Nianine, A.; Nikitin, V.; Nikolaev, S.; Nishimura, S.; Nomokov, P.; Nystrand, J.; Obenshain, F.E.; Oskarsson, A.; Otterlund, I.; Pachr, M.; Parfenov, A.; Pavliouk, S.; Peitzmann, T.; Petracek, V.; Plasil, F.; Purschke, M.L.; Raeven, B.; Rak, J.; Raniwala, S.; Ramamurthy, V.S.; Rao, N.K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Rubio, J.M.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.R.; Shabratova, G.; Sibaryak, I.; Siemiarczuk, T.; Sinha, B.C.; Slavin, N.; Soderstrom, K.; Solomey, N.; Sorensen, S.P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Stuken, D.; Sumbera, M.; Svensson, T.; Trivedi, M.D.; Tsvetkov, A.; Twenhofel, C.; Tykarski, L.; Urbahn, J.; van Eijndhoven, N.; van Heeringen, W.H.; van Nieuwenhuizen, G.J.; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.S.; Voros, S.; Vos, M.A.; Wyslouch, B.; Yagi, K.; Yokota, Y.; Young, G.R.; Nayak, Tapan K.


    Disoriented Chiral Condensates (DCC) have been predicted to form in high energy heavy ion collisions where the approximate chiral symmetry of QCD has been restored. This leads to large imbalances in the production of charged to neutral pions. Sophisticated analysis methods are being developed to disentangle DCC events out of the large background of events with conventionally produced particles. We present a short review of current analysis methods and future prospects.

  12. Using rotor or tip speed in the acoustical analysis of small wind turbines (United States)

    Acoustical noise data have been collected and analyzed on small wind turbines used for water pumping at the USDA-ARS Conservation and Production Research Laboratory (CPRL) near Bushland, Texas. This acoustical analysis differed from previous research in that the data were analyzed with rotor or tip ...

  13. Acoustic measurements on trees and logs: a review and analysis (United States)

    Xiping Wang


    Acoustic technologies have been well established as material evaluation tools in the past several decades, and their use has become widely accepted in the forest products industry for online quality control and products grading. Recent research developments on acoustic sensing technology offer further opportunities to evaluate standing trees and logs for general wood...

  14. An experimental analysis of fracture mechanisms by acoustic ...

    African Journals Online (AJOL)

    Burst pressure prediction in graphite/epoxy pressure vessels using neural networks and acoustic emission amplitude data, Materials Evaluation, Vol.54(6), pp.744 ... of emission acoustic signals collected during tensile tests on unidirectional glass/polyester composite using supervised and unsupervised classifiers, NDT & E.

  15. Prediction of the acoustical performance of enclosures using a hybrid statistical energy analysis: image source model. (United States)

    Sgard, Franck; Nelisse, Hugues; Atalla, Noureddine; Amedin, Celse Kafui; Oddo, Remy


    Enclosures are commonly used to reduce the sound exposure of workers to the noise radiated by machinery. Some acoustic predictive tools ranging from simple analytical tools to sophisticated numerical deterministic models are available to estimate the enclosure acoustical performance. However, simple analytical models are usually valid in limited frequency ranges because of underlying assumptions whereas numerical models are commonly limited to low frequencies. This paper presents a general and simple model for predicting the acoustic performance of large free-standing enclosures which is capable of taking into account the complexity of the enclosure configuration and covering a large frequency range. It is based on the statistical energy analysis (SEA) framework. The sound field inside the enclosure is calculated using the method of image sources. Sound transmission across the various elements of the enclosure is considered in the SEA formalism. The model is evaluated by comparison with existing methods and experimental results. The effect of several parameters such as enclosure geometry, panel materials, presence of noise control treatments, location of the source inside the enclosure, and presence of an opening has been investigated. The comparisons between the model and the experimental results show a good agreement for most of the tested configurations.

  16. Cluster analysis of acoustic emission signals for 2D and 3D woven carbon fiber/epoxy composites


    Li, Li; Swolfs, Yentl; Straumit, Ilya; Yan, Xiong; Lomov, Stepan Vladimirovitch


    Understanding the failure mechanisms in textile composites based on acoustic emission (AE) signals is a challenging task. In the present work, unsupervised cluster analysis is performed on the AE data registered during tensile tests on 2D and 3D woven carbon fiber/epoxy composites. The analysis is based on the k-means++ algorithm and principal component analysis. Peak amplitude and frequency features – peak frequency for 2D woven composites and frequency centroid for 3D woven composites – wer...

  17. Characteristics Analysis of Joint Acoustic Echo and Noise Suppression in Periodic Drillstring Waveguide

    Directory of Open Access Journals (Sweden)

    Li Cheng


    Full Text Available A new method of wireless data telemetry used by oil industry uses compressional acoustic waves to transmit downhole information from the bottom hole to the surface. Unfortunately, acoustic echoes and drilling vibration noises in periodic drillstring are a major issue in transmission performance. A combined acoustic echo and noise suppression method based on wave motion characteristic in drillstring is adopted to enhance an upward-going transmitted acoustic signal. The presented scheme consists of a primary acoustic echo canceller using an array of two accelerometers for dealing with the downward-going noises and a secondary acoustic insulation structure for restraining the upward-going vibration noises. Furthermore, the secondary acoustic insulation structure exhibits a banded and dispersive spectral structure because of periodic groove configuration. By using a finite-differential algorithm for the one-dimensional propagation of longitudinal waves, acoustic receiving characteristics of transmitted signals are simulated with additive Gaussian noise in a periodic pipe structure of limited length to investigate the effects on transmission performance optimization. The results reveal that the proposed scheme can achieve a much lower error bit ratio over a specified acoustic isolation frequency range with a 30–40 dB reduction in the average noise level compared to traditional single-receiver scheme.

  18. Surface acoustic wave nebulization facilitating lipid mass spectrometric analysis. (United States)

    Yoon, Sung Hwan; Huang, Yue; Edgar, J Scott; Ting, Ying S; Heron, Scott R; Kao, Yuchieh; Li, Yanyan; Masselon, Christophe D; Ernst, Robert K; Goodlett, David R


    Surface acoustic wave nebulization (SAWN) is a novel method to transfer nonvolatile analytes directly from the aqueous phase to the gas phase for mass spectrometric analysis. The lower ion energetics of SAWN and its planar nature make it appealing for analytically challenging lipid samples. This challenge is a result of their amphipathic nature, labile nature, and tendency to form aggregates, which readily precipitate clogging capillaries used for electrospray ionization (ESI). Here, we report the use of SAWN to characterize the complex glycolipid, lipid A, which serves as the membrane anchor component of lipopolysaccharide (LPS) and has a pronounced tendency to clog nano-ESI capillaries. We also show that unlike ESI SAWN is capable of ionizing labile phospholipids without fragmentation. Lastly, we compare the ease of use of SAWN to the more conventional infusion-based ESI methods and demonstrate the ability to generate higher order tandem mass spectral data of lipid A for automated structure assignment using our previously reported hierarchical tandem mass spectrometry (HiTMS) algorithm. The ease of generating SAWN-MS(n) data combined with HiTMS interpretation offers the potential for high throughput lipid A structure analysis.

  19. Fuzzy net present value for engineering analysis

    Directory of Open Access Journals (Sweden)

    Ali Nazeri


    Full Text Available Cash flow analysis is one of the most popular methods for investigating the outcome of an economical project. The costs and benefits of a construction project are often involved with uncertainty and it is not possible to find a precise value for a particular project. In this paper, we present a simple method to calculate the net present value of a cash flow when both costs and benefits are given as triangular numbers. The proposed model of this paper uses Delphi method to figure out the fair values of all costs and revenues and then using fizzy programming techniques, it calculates the fuzzy net present value. The implementation of the proposed model is demonstrated using a simple example.

  20. Nonstationary System Analysis Methods for Underwater Acoustic Communications

    National Research Council Canada - National Science Library

    Josso, Nicolas F; Zhang, Jun Jason; Papandreou-Suppappola, Antonia; Ioana, Cornel; Duman, Tolga M


    .... In underwater acoustic communications using medium-to-high frequencies (0.3–20 kHz), the nonstationary transformation on the transmitted signals can be modeled as multiple time-delay and Doppler-scaling paths...

  1. Analysis of Reverberation Time Field Measurement Results in Building Acoustics


    D. Mašović; M. Öğüç


    Sound level difference between two rooms depends on both sound reduction between the rooms and their acoustical properties, such as the absorption in the receiving room. In order to abstract the influence of the rooms and assess only the sound reduction between them, relevant building acoustics standards offer two ways of normalizing a measured sound level difference – according to the reverberation time and the equivalent sound absorption area in the receiving room. In both cases measurement...

  2. Analysis of acoustic parameters for consonant voicing classification in clean and telephone speech. (United States)

    Lee, Suk-Myung; Choi, Jeung-Yoon


    This paper describes acoustic cues for classification of consonant voicing in a distinctive feature-based speech recognition system. Initial acoustic cues are selected by studying consonant production mechanisms. Spectral representations, band-limited energies, and correlation values, along with Mel-frequency cepstral coefficients features (MFCCs) are also examined. Analysis of variance is performed to assess relative significance of features. Overall, 82.2%, 80.6%, and 78.4% classification rates are obtained on the TIMIT database for stops, fricatives, and affricates, respectively. Combining acoustic parameters with MFCCs shows performance improvement in all cases. Also, performance in the NTIMIT telephone channel speech shows that acoustic parameters are more robust than MFCCs. © 2012 Acoustical Society of America

  3. Built Environment Energy Analysis Tool Overview (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Porter, C.


    This presentation provides an overview of the Built Environment Energy Analysis Tool, which is designed to assess impacts of future land use/built environment patterns on transportation-related energy use and greenhouse gas (GHG) emissions. The tool can be used to evaluate a range of population distribution and urban design scenarios for 2030 and 2050. This tool was produced as part of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  4. Electrical circuit modeling and analysis of microwave acoustic interaction with biological tissues. (United States)

    Gao, Fei; Zheng, Qian; Zheng, Yuanjin


    Numerical study of microwave imaging and microwave-induced thermoacoustic imaging utilizes finite difference time domain (FDTD) analysis for simulation of microwave and acoustic interaction with biological tissues, which is time consuming due to complex grid-segmentation and numerous calculations, not straightforward due to no analytical solution and physical explanation, and incompatible with hardware development requiring circuit simulator such as SPICE. In this paper, instead of conventional FDTD numerical simulation, an equivalent electrical circuit model is proposed to model the microwave acoustic interaction with biological tissues for fast simulation and quantitative analysis in both one and two dimensions (2D). The equivalent circuit of ideal point-like tissue for microwave-acoustic interaction is proposed including transmission line, voltage-controlled current source, envelop detector, and resistor-inductor-capacitor (RLC) network, to model the microwave scattering, thermal expansion, and acoustic generation. Based on which, two-port network of the point-like tissue is built and characterized using pseudo S-parameters and transducer gain. Two dimensional circuit network including acoustic scatterer and acoustic channel is also constructed to model the 2D spatial information and acoustic scattering effect in heterogeneous medium. Both FDTD simulation, circuit simulation, and experimental measurement are performed to compare the results in terms of time domain, frequency domain, and pseudo S-parameters characterization. 2D circuit network simulation is also performed under different scenarios including different sizes of tumors and the effect of acoustic scatterer. The proposed circuit model of microwave acoustic interaction with biological tissue could give good agreement with FDTD simulated and experimental measured results. The pseudo S-parameters and characteristic gain could globally evaluate the performance of tumor detection. The 2D circuit network

  5. Air-coupled acoustic radiation force source for non-contact measurement of soft media elasticity (Conference Presentation) (United States)

    Ambroziński, Lukasz; Pelivanov, Ivan; Song, Shaozhen; Yoon, Soon Joon; Li, David S.; Gao, Liang; Shen, Tueng T.; Wang, Ruikang K.; O'Donnell, Matthew


    Acoustic radiation force (ARF) is commonly used in ultrasound (US)-based elastography to generate shear waves deep within soft tissue. These waves can be detected with different methods, e.g. contact conventional ultrasound imaging probes or contact free magnetic resonance or optical coherence tomography (OCT). For many clinical applications, however, for instance the eye, a totally non-contact system for generation/detection of mechanical waves is needed. Here, we present a method for efficient non-contact excitation of broadband transverse mechanical waves in soft media. The approach is based on pushing the medium under study with a 1 MHz chirped US wave focused to its surface from air. The US beam reflected from the air/medium interface provides the ARF force to the medium surface launching a transient mechanical wave in the transverse (lateral) direction. The design and performance of the air-coupled transducer is discussed. The focal zone, peak pressure and acoustic intensity are measured for transducers with different numerical apertures. Time and frequency characteristics of the propagating mechanical waves, generated in soft tissue, are tracked with a phase-sensitive ultra-fast frame rate OCT imaging system. Application of the proposed method for non-contact, non-invasive, sub-mm resolution elasticity measurement in soft tissue is proposed.

  6. Quantitative Analysis Of Acoustic Emission From Rock Fracture Experiments (United States)

    Goodfellow, Sebastian David

    This thesis aims to advance the methods of quantitative acoustic emission (AE) analysis by calibrating sensors, characterizing sources, and applying the results to solve engi- neering problems. In the first part of this thesis, we built a calibration apparatus and successfully calibrated two commercial AE sensors. The ErgoTech sensor was found to have broadband velocity sensitivity and the Panametrics V103 was sensitive to surface normal displacement. These calibration results were applied to two AE data sets from rock fracture experiments in order to characterize the sources of AE events. The first data set was from an in situ rock fracture experiment conducted at the Underground Research Laboratory (URL). The Mine-By experiment was a large scale excavation response test where both AE (10 kHz - 1 MHz) and microseismicity (MS) (1 Hz - 10 kHz) were monitored. Using the calibration information, magnitude, stress drop, dimension and energy were successfully estimated for 21 AE events recorded in the tensile region of the tunnel wall. Magnitudes were in the range -7.5 seismicity in the field (0.1 - 10 MPa). The second data set was AE collected during a true-triaxial deformation experiment, where the objectives were to characterize laboratory AE sources and identify issues related to moving the analysis from ideal in situ conditions to more complex laboratory conditions in terms of the ability to conduct quantitative AE analysis. We found AE magnitudes in the range -7.8 seismic energy radiated is between 1e-7 % and 1e-3 % of the injection energy. We tested these findings by calculating the AE energy as a percentage of the injection energy and found that for eight laboratory hydraulic fracture experiments, the seismic energy ranged from 7.02e-08 % to 1.24e-04 % of the injection energy. These results support those made in the field, which concludes that seismic energy projection is a very small component of the hydraulic fracture energy budget and that the dominant energy

  7. Acoustic emission analysis for the detection of appropriate cutting operations in honing processes (United States)

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


    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.

  8. Signal analysis of acoustic and flow-induced vibrations of BWR main steam line

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, G., E-mail: [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Prieto-Guerrero, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Núñez-Carrera, A. [Comisión Nacional de Seguridad Nuclear y Salvaguardias, Doctor Barragán 779, Col. Narvarte, México, D.F. 03020 (Mexico); Vázquez-Rodríguez, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Centeno-Pérez, J. [Instituto Politécnico Nacional, Escuela Superior de Física y Matemáticas Unidad Profesional “Adolfo López Mateos”, Av. IPN, s/n, México, D.F. 07738 (Mexico); Espinosa-Martínez, E.-G. [Departamento de Sistemas Energéticos, Universidad Nacional Autónoma de México, México, D.F. 04510 (Mexico); and others


    Highlights: • Acoustic and flow-induced vibrations of BWR are analyzed. • BWR performance after extended power uprate is considered. • Effect of acoustic side branches (ASB) is analyzed. • The ASB represents a reduction in the acoustic loads to the steam dryer. • Methodology developed for simultaneous analyzing the signals in the MSL. - Abstract: The aim of this work is the signal analysis of acoustic waves due to phenomenon known as singing in Safety Relief Valves (SRV) of the main steam lines (MSL) in a typical BWR5. The acoustic resonance in SRV standpipes and fluctuating pressure is propagated from SRV to the dryer through the MSL. The signals are analyzed with a novel method based on the Multivariate Empirical Mode Decomposition (M-EMD). The M-EMD algorithm has the potential to find common oscillatory modes (IMF) within multivariate data. Based on this fact, we implement the M-EMD technique to find the oscillatory mode in BWR considering the measurements obtained collected by the strain gauges located around the MSL. These IMF, analyzed simultaneously in time, allow obtaining an estimation of the effects of the multiple-SRV in the MSL. Two scenarios are analyzed: the first is the signal obtained before the installation of the acoustic dampers (ASB), and the second, the signal obtained after installation. The results show the effectiveness of the ASB to damp the strong resonances when the steam flow increases, which represents an important reduction in the acoustic loads to the steam dryer.

  9. Analysis of acoustic resonator with shape deformation using finite ...

    Indian Academy of Sciences (India)

    An acoustic resonator with shape deformation has been analysed using the finite element method. The shape deformation issuch that the volume of the resonator remains constant. The effect of deformation on the resonant frequencies is studied. Deformation splits the degenerate frequencies.

  10. Analysis of acoustic resonator with shape deformation using finite ...

    Indian Academy of Sciences (India)

    using the finite element method. The shape deformation is such that the volume of the resonator remains constant. The effect of deformation on the resonant frequencies is studied. Deformation splits the degenerate frequencies. Keywords. Finite element method; acoustic resonator; degenerate frequency. 1. Introduction.

  11. Monitoring and Analysis of In-Pile Phenomena in Advanced Test Reactor using Acoustic Telemetry

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States). Dept. of Human Factors, Controls, and Statistics; Smith, James A. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Dept. of Fuel Performance and Design; Jewell, James Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States). Dept. of Fuel Performance and Design


    The interior of a nuclear reactor presents a particularly harsh and challenging environment for both sensors and telemetry due to high temperatures and high fluxes of energetic and ionizing particles among the radioactive decay products. A number of research programs are developing acoustic-based sensing approach to take advantage of the acoustic transmission properties of reactor cores. Idaho National Laboratory has installed vibroacoustic receivers on and around the Advanced Test Reactor (ATR) containment vessel to take advantage of acoustically telemetered sensors such as thermoacoustic (TAC) transducers. The installation represents the first step in developing an acoustic telemetry infrastructure. This paper presents the theory of TAC, application of installed vibroacoustic receivers in monitoring the in-pile phenomena inside the ATR, and preliminary data processing results.

  12. Experimental Acoustic Evaluation of an Auditorium

    Directory of Open Access Journals (Sweden)

    Marina Dana Ţopa


    Full Text Available The paper presents a case history: the acoustical analysis of a rectangular auditorium. The following acoustical parameters were evaluated: early decay time, reverberation time, clarity, definition, and center time. The excitation signal was linear sweep sine and additional analysis was carried out: peak-to-noise ratio, reverberation time for empty and occupied room, standard deviation of acoustical parameters, diffusion, and just noticeable differences analysis. Conclusions about room’s destination and modeling were drawn in the end.

  13. Error Analysis: Past, Present, and Future (United States)

    McCloskey, George


    This commentary will take an historical perspective on the Kaufman Test of Educational Achievement (KTEA) error analysis, discussing where it started, where it is today, and where it may be headed in the future. In addition, the commentary will compare and contrast the KTEA error analysis procedures that are rooted in psychometric methodology and…

  14. Instructional Cost Analysis: History and Present Inadequacies. (United States)

    Humphrey, David A.

    The cost analysis of instruction is conducted according to principles of teaching and learning that have often become historically dated. Using today's costing systems prevents determination of whether cost effectiveness actually exists. The patterns of instruction in higher education and the systems employed for instructional cost analysis are…

  15. Enhanced tagging of light utilizing acoustic radiation force with speckle pattern analysis (United States)

    Vakili, Ali; Hollmann, Joseph L.; Holt, R. Glynn; DiMarzio, Charles A.


    In optical imaging, the depth and resolution are limited due to scattering. Unlike light, scattering of ultrasound (US) waves in tissue is negligible. Hybrid imaging methods such as US-modulated optical tomography (UOT) use the advantages of both modalities. UOT tags light by inducing phase change caused by modulating the local index of refraction of the medium. The challenge in UOT is detecting the small signal. The displacement induced by the acoustic radiation force (ARF) is another US effect that can be utilized to tag the light. It induces greater phase change, resulting in a stronger signal. Moreover, the absorbed acoustic energy generates heat, resulting in change in the index of refraction and a strong phase change. The speckle pattern is governed by the phase of the interfering scattered waves; hence, speckle pattern analysis can obtain information about displacement and temperature changes. We have presented a model to simulate the insonation processes. Simulation results based on fixed-particle Monte Carlo and experimental results show that the signal acquired by utilizing ARF is stronger compared to UOT. The introduced mean irradiance change (MIC) signal reveals both thermal and mechanical effects of the focused US beam in different timescales. Simulation results suggest that variation in the MIC signal can be used to generate a displacement image of the medium.

  16. Trade-off Analysis of Underwater Acoustic Sensor Networks (United States)

    Tuna, G.; Das, R.


    In the last couple of decades, Underwater Acoustic Sensor Networks (UASNs) were started to be used for various commercial and non-commercial purposes. However, in underwater environments, there are some specific inherent constraints, such as high bit error rate, variable and large propagation delay, limited bandwidth capacity, and short-range communications, which severely degrade the performance of UASNs and limit the lifetime of underwater sensor nodes as well. Therefore, proving reliability of UASN applications poses a challenge. In this study, we try to balance energy consumption of underwater acoustic sensor networks and minimize end-to-end delay using an efficient node placement strategy. Our simulation results reveal that if the number of hops is reduced, energy consumption can be reduced. However, this increases end-to-end delay. Hence, application-specific requirements must be taken into consideration when determining a strategy for node deployment.

  17. Acoustical User Identification Based on MFCC Analysis of Keystrokes

    Directory of Open Access Journals (Sweden)

    Matus Pleva


    Full Text Available This paper introduces a novel approach of person identification using acoustical monitoring of typing the required word on the monitored keyboard. This experiment was motivated by the idea of COST IC1106 (Integrating Biometrics and Forensics for the Digital Age partners to acoustically analyse the captured keystroke dynamics database using widely used time-invariant mathematical models tools. The MFCC (Mel-Frequency Cepstral Coefficients and HMM (Hidden Markov Models was introduced in this experiment, which gives promising results of 99.33% accuracy, when testing 25% of realizations (randomly selected from 100 identifying between 50 users/models. The experiment was repeated for different training/testing configurations and cross-validated, so this first approach could be a good starting point for next research including feature selection algorithms, biometric authentication score normalization, different audio & keyboard setup tests, etc.

  18. Acoustic Seaglider: PhilSea10 Data Analysis (United States)


    Ocean Atlas climatology in the deep ocean. Figure 3. Received acoustic data (top) on SG023 from the 1800 transmission of source T2 on 2010...384.6 km), T4 (blue, 563.0 km), and T5 (magenta, 493.5 km) for SG513 Dive 204, Reception 1 (top). Diamonds of the same colors indicate arcs (bottom) shows the DR dynamically estimated positions for each source reception (stars corresponding in color with those listed above) and

  19. Analysis of Reverberation Time Field Measurement Results in Building Acoustics

    Directory of Open Access Journals (Sweden)

    D. Mašović


    Full Text Available Sound level difference between two rooms depends on both sound reduction between the rooms and their acoustical properties, such as the absorption in the receiving room. In order to abstract the influence of the rooms and assess only the sound reduction between them, relevant building acoustics standards offer two ways of normalizing a measured sound level difference – according to the reverberation time and the equivalent sound absorption area in the receiving room. In both cases measurement procedure requires reverberation time measurements in the receiving room, from which the equivalent sound absorption area can be assessed using Sabine’s formula. This paper analyses more than 300 results of reverberation time field measurements and provides an insight into its typical values in buildings. The measurements are done by five teams of building acoustics engineers, mostly involved in the international EU COST Action TU0901. The results are gathered in a unique database as a part of the STSM (Short Term Scientific Mission.

  20. Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films (United States)

    Hines, Jacqueline H. (Inventor)


    A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

  1. Acoustic analysis of speech through a hearing aid: perceptual effects of changes with two-channel compression. (United States)

    Hickson, Louise; Thyer, Nick


    Compression amplification significantly alters the acoustic speech signal in comparison to linear amplification. The central hypothesis of the present study was that the compression settings of a two-channel aid that best preserved the acoustic properties of speech compared to linear amplification would yield the best perceptual results, and that the compression settings that most altered the acoustic properties of speech compared to linear would yield significantly poorer speech perception. On the basis of initial acoustic analysis of the test stimuli recorded through a hearing aid, two different compression amplification settings were chosen for the perceptual study. Participants were 74 adults with mild to moderate sensorineural hearing impairment. Overall, the speech perception results supported the hypothesis. A further aim of the study was to determine if variation in participants' speech perception with compression amplification (compared to linear amplification) could be explained by the individual characteristics of age, degree of loss, dynamic range, temporal resolution, and frequency selectivity; however, no significant relationships were found.

  2. Time-frequency analysis of acoustic emission signals generated by the Glass Fibre Reinforced Polymer Composites during the tensile test (United States)

    Świt, G.; Adamczak, A.; Krampikowska, A.


    Fibre reinforced polymer composites are currently dominating in the composite materials market. The lack of detailed knowledge about their properties and behaviour in various conditions of exposure under load significantly limits the broad possibilities of application of these materials. Occurring and accumulation of defects in material during the exploitation of the construction lead to the changes of its technical condition. The necessity to control the condition of the composite is therefore justified. For this purpose, non-destructive method of acoustic emission can be applied. This article presents an example of application of acoustic emission method based on time analysis and time-frequency analysis for the evaluation of the progress of the destructive processes and the level of degradation of glass fibre reinforced composite tapes that were subject to tensile testing.

  3. Aeroacoustic analysis of the human phonation process based on a hybrid acoustic PIV approach (United States)

    Lodermeyer, Alexander; Tautz, Matthias; Becker, Stefan; Döllinger, Michael; Birk, Veronika; Kniesburges, Stefan


    The detailed analysis of sound generation in human phonation is severely limited as the accessibility to the laryngeal flow region is highly restricted. Consequently, the physical basis of the underlying fluid-structure-acoustic interaction that describes the primary mechanism of sound production is not yet fully understood. Therefore, we propose the implementation of a hybrid acoustic PIV procedure to evaluate aeroacoustic sound generation during voice production within a synthetic larynx model. Focusing on the flow field downstream of synthetic, aerodynamically driven vocal folds, we calculated acoustic source terms based on the velocity fields obtained by time-resolved high-speed PIV applied to the mid-coronal plane. The radiation of these sources into the acoustic far field was numerically simulated and the resulting acoustic pressure was finally compared with experimental microphone measurements. We identified the tonal sound to be generated downstream in a small region close to the vocal folds. The simulation of the sound propagation underestimated the tonal components, whereas the broadband sound was well reproduced. Our results demonstrate the feasibility to locate aeroacoustic sound sources inside a synthetic larynx using a hybrid acoustic PIV approach. Although the technique employs a 2D-limited flow field, it accurately reproduces the basic characteristics of the aeroacoustic field in our larynx model. In future studies, not only the aeroacoustic mechanisms of normal phonation will be assessable, but also the sound generation of voice disorders can be investigated more profoundly.

  4. Decay of coherent acoustic phonons generated by femtosecond pulsed optical excitation and injected in a Wannier-Stark superlattice (Conference Presentation) (United States)

    Kent, Anthony J.; Poyser, Caroline L.; Akimov, Andrey V.; York, William; Henini, Mohamed; Campion, Richard P.


    In the past decade, sound amplification by the stimulated emission of (acoustic phonon) radiation (saser) devices for generating coherent terahertz (THz) acoustic waves have been demonstrated [1 - 3]. The devices exploit the electron-phonon interactions in periodic semiconductor nanostructures known as superlattices (SLs) to amplify acoustic phonons. In addition, the particular acoustic properties of SLs can be exploited to make mirrors and cavities for THz phonons. Thus SLs can provide the two essential elements of a saser: the acoustic gain medium and the acoustic cavity. In this presentation I will describe experimental studies of the THz phonon dynamics in a weakly-coupled GaAs/AlAs saser SL, which is DC electrically biased into the Wannier-Stark regime. Picoseconds-duration pulses of coherent THz acoustic phonons were generated using pump light pulses from a femtosecond laser and injected into the SL device. These phonon pulses seeded the saser cavity modes at about 220 and 440 GHz, which were amplified within the device. The phonons were detected using two methods: reflection of femtosecond probe light pulses, in a conventional pump-probe arrangement, and through the transient electrical response of the device itself. When the DC bias conditions for saser were achieved in the device, the amplitude and lifetime of the seeded modes were both increased, analogous to the threshold and spectral line narrowing effects seen in laser devices. [1] R P Beardsley et al., Phys. Rev. Lett. 104, 085501 (2010). [2] W Maryam et al., Nature Communications 4:2184 (2013). [3] K Shinokita et al., Phys. Rev. Lett. 116, 075504 (2016).

  5. Controlled Hydrogen Fleet and Infrastructure Analysis (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Wipke, K.; Sprik, S.; Kurtz, J.; Ramsden, T.; Ainscough, C.; Saur, G.


    This is a presentation about the Fuel Cell Electric Vehicle Learning Demo, a 7-year project and the largest single FCEV and infrastructure demonstration in the world to date. Information such as its approach, technical accomplishments and progress; collaborations and future work are discussed.

  6. A Novel Acoustic Liquid Level Determination Method for Coal Seam Gas Wells Based on Autocorrelation Analysis

    Directory of Open Access Journals (Sweden)

    Ximing Zhang


    Full Text Available In coal seam gas (CSG wells, water is periodically removed from the wellbore in order to keep the bottom-hole flowing pressure at low levels, facilitating the desorption of methane gas from the coal bed. In order to calculate gas flow rate and further optimize well performance, it is necessary to accurately monitor the liquid level in real-time. This paper presents a novel method based on autocorrelation function (ACF analysis for determining the liquid level in CSG wells under intense noise conditions. The method involves the calculation of the acoustic travel time in the annulus and processing the autocorrelation signal in order to extract the weak echo under high background noise. In contrast to previous works, the non-linear dependence of the acoustic velocity on temperature and pressure is taken into account. To locate the liquid level of a coal seam gas well the travel time is computed iteratively with the non-linear velocity model. Afterwards, the proposed method is validated using experimental laboratory investigations that have been developed for liquid level detection under two scenarios, representing the combination of low pressure, weak signal, and intense noise generated by gas flowing and leakage. By adopting an evaluation indicator called Crest Factor, the results have shown the superiority of the ACF-based method compared to Fourier filtering (FFT. In the two scenarios, the maximal measurement error from the proposed method was 0.34% and 0.50%, respectively. The latent periodic characteristic of the reflected signal can be extracted by the ACF-based method even when the noise is larger than 1.42 Pa, which is impossible for FFT-based de-noising. A case study focused on a specific CSG well is presented to illustrate the feasibility of the proposed approach, and also to demonstrate that signal processing with autocorrelation analysis can improve the sensitivity of the detection system.

  7. Freddie Mercury-acoustic analysis of speaking fundamental frequency, vibrato, and subharmonics. (United States)

    Herbst, Christian T; Hertegard, Stellan; Zangger-Borch, Daniel; Lindestad, Per-Åke


    Freddie Mercury was one of the twentieth century's best-known singers of commercial contemporary music. This study presents an acoustical analysis of his voice production and singing style, based on perceptual and quantitative analysis of publicly available sound recordings. Analysis of six interviews revealed a median speaking fundamental frequency of 117.3 Hz, which is typically found for a baritone voice. Analysis of voice tracks isolated from full band recordings suggested that the singing voice range was 37 semitones within the pitch range of F#2 (about 92.2 Hz) to G5 (about 784 Hz). Evidence for higher phonations up to a fundamental frequency of 1,347 Hz was not deemed reliable. Analysis of 240 sustained notes from 21 a-cappella recordings revealed a surprisingly high mean fundamental frequency modulation rate (vibrato) of 7.0 Hz, reaching the range of vocal tremor. Quantitative analysis utilizing a newly introduced parameter to assess the regularity of vocal vibrato corroborated its perceptually irregular nature, suggesting that vibrato (ir)regularity is a distinctive feature of the singing voice. Imitation of subharmonic phonation samples by a professional rock singer, documented by endoscopic high-speed video at 4,132 frames per second, revealed a 3:1 frequency locked vibratory pattern of vocal folds and ventricular folds.

  8. Field support, data analysis and associated research for the acoustic grenade sounding program (United States)

    Barnes, T. G.; Bullard, E. R.


    Temperature and horizontal winds in the 30 to 90 km altitude range of the upper atmosphere, were determined by acoustic grenade soundings conducted at Wallops Island, Virginia and Kourou, French Guiana. Field support provided at these locations included deployment of the large area microphone system, supervision, maintenance and operation of sound ranging stations; and coordination of activities. Data analysis efforts included the analysis of field data to determine upper atmospheric meteorological parameters. Profiles for upper atmospheric temperature, wind and density are provided in plots and tables for each of the acoustic grenade soundings conducted during the contract period. Research efforts were directed toward a systematic comparison of temperature data from acoustic grenade with other meteorological sensor probes in the upper atmosphere.

  9. Acoustical analysis and multiple source auralizations of charismatic worship spaces (United States)

    Lee, Richard W.


    Because of the spontaneity and high level of call and response, many charismatic churches have verbal and musical communication problems that stem from highly reverberant sound fields, poor speech intelligibility, and muddy music. This research looks at the subjective dimensions of room acoustics perception that affect a charismatic worship space, which is summarized using the acronym RISCS (reverberation, intimacy, strength, coloration, and spaciousness). The method of research is to obtain acoustical measurements for three worship spaces in order to analyze the objective parameters associated with the RISCS subjective dimensions. For the same spaces, binaural room impulse response (BRIR) measurements are done for different receiver positions in order to create an auralization for each position. The subjective descriptors of RISCS are analyzed through the use of listening tests of the three auralized spaces. The results from the measurements and listening tests are analyzed to determine if listeners' perceptions correlate with the objective parameter results, the appropriateness of the subjective parameters for the use of the space, and which parameters seem to take precedent. A comparison of the multi-source auralization to a conventional single-source auralization was done with the mixed down version of the synchronized multi-track anechoic signals.

  10. Vibration impact acoustic emission technique for identification and analysis of defects in carbon steel tubes: Part A Statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Zakiah Abd [Universiti Teknikal Malaysia Melaka (Malaysia); Jamaludin, Nordin; Junaidi, Syarif [Faculty of Engineering and Built, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Yahya, Syed Yusainee Syed [Universiti Teknologi MARA, Shah Alam (Malaysia)


    Current steel tubes inspection techniques are invasive, and the interpretation and evaluation of inspection results are manually done by skilled personnel. This paper presents a statistical analysis of high frequency stress wave signals captured from a newly developed noninvasive, non-destructive tube inspection technique known as the vibration impact acoustic emission (VIAE) technique. Acoustic emission (AE) signals have been introduced into the ASTM A179 seamless steel tubes using an impact hammer, and the AE wave propagation was captured using an AE sensor. Specifically, a healthy steel tube as the reference tube and four steel tubes with through-hole artificial defect at different locations were used in this study. The AE features extracted from the captured signals are rise time, peak amplitude, duration and count. The VIAE technique also analysed the AE signals using statistical features such as root mean square (r.m.s.), energy, and crest factor. It was evident that duration, count, r.m.s., energy and crest factor could be used to automatically identify the presence of defect in carbon steel tubes using AE signals captured using the non-invasive VIAE technique.

  11. Time series analysis of tool wear in sheet metal stamping using acoustic emission (United States)

    Vignesh Shanbhag, V.; Pereira, P. Michael; Rolfe, F. Bernard; Arunachalam, N.


    Galling is an adhesive wear mode that often affects the lifespan of stamping tools. Since stamping tools represent significant economic cost, even a slight improvement in maintenance cost is of high importance for the stamping industry. In other manufacturing industries, online tool condition monitoring has been used to prevent tool wear-related failure. However, monitoring the acoustic emission signal from a stamping process is a non-trivial task since the acoustic emission signal is non-stationary and non-transient. There have been numerous studies examining acoustic emissions in sheet metal stamping. However, very few have focused in detail on how the signals change as wear on the tool surface progresses prior to failure. In this study, time domain analysis was applied to the acoustic emission signals to extract features related to tool wear. To understand the wear progression, accelerated stamping tests were performed using a semi-industrial stamping setup which can perform clamping, piercing, stamping in a single cycle. The time domain features related to stamping were computed for the acoustic emissions signal of each part. The sidewalls of the stamped parts were scanned using an optical profilometer to obtain profiles of the worn part, and they were qualitatively correlated to that of the acoustic emissions signal. Based on the wear behaviour, the wear data can be divided into three stages: - In the first stage, no wear is observed, in the second stage, adhesive wear is likely to occur, and in the third stage severe abrasive plus adhesive wear is likely to occur. Scanning electron microscopy showed the formation of lumps on the stamping tool, which represents galling behavior. Correlation between the time domain features of the acoustic emissions signal and the wear progression identified in this study lays the basis for tool diagnostics in stamping industry.

  12. Tempo and beat analysis of acoustic musical signals. (United States)

    Scheirer, E D


    A method is presented for using a small number of bandpass filters and banks of parallel comb filters to analyze the tempo of, and extract the beat from, musical signals of arbitrary polyphonic complexity and containing arbitrary timbres. This analysis is performed causally, and can be used predictively to guess when beats will occur in the future. Results in a short validation experiment demonstrate that the performance of the algorithm is similar to the performance of human listeners in a variety of musical situations. Aspects of the algorithm are discussed in relation to previous high-level cognitive models of beat tracking.

  13. Acoustic analysis of voice in normal and high pitch phonation: a comparative study. (United States)

    Aithal, Venkataraja U; Bellur, Rajashekhar; John, Sunila; Varghese, Ciji; Guddattu, Vasudeva


    Comparison of acoustic parameters of voice between normal and high pitch phonation in normal adults, and comparison between genders. A total of 48 normal laryngeal speakers were considered for this study. The acoustic parameters were analyzed using the Multi-Dimensional Voice Program. Descriptive statistics were used for analysis of the acoustic parameters across tasks and genders. Paired-samples t tests were used to compare measures between tasks. Independent-samples t tests were used to compare parameters between genders. Significant differences were found across tasks in the range of fundamental frequency and average fundamental frequency. Females showed a significant difference in the frequency perturbation measures – percent jitter and relative average perturbation, while males demonstrated a significant difference in the noise-to-harmonic ratio. While comparing mean differences between genders, significant differences were observed in fundamental frequency, range of the fundamental frequency, and smoothed pitch perturbation quotient during both phonation tasks. Comparison of acoustic parameters between normal and high pitch phonation would facilitate understanding the effect of high pitch phonation on voice parameters. Subsequently, this would help clinicians to focus on important acoustic parameters while assessing professional voice users who are at risk of developing voice problems.

  14. Battlefield acoustics

    CERN Document Server

    Damarla, Thyagaraju


    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...

  15. Multi-Layer Phase Analysis: Quantifying the Elastic Properties of Soft Tissues and Live Cells with Ultra-High Frequency Scanning Acoustic Microscopy (United States)

    Zhao, Xuegen; Akhtar, Riaz; Nijenhuis, Nadja; Wilkinson, Steven J.; Murphy, Lilli; Ballestrem, Christoph; Sherratt, Michael. J.; Watson, Rachel E.B.; Derby, Brian


    Scanning acoustic microscopy is potentially a powerful tool for characterising the elastic properties of soft biological tissues and cells. In this paper, we present a method, Multi-Layer Phase Analysis (MLPA), which can be used to extract local speed of sound values, for both thin tissue sections mounted on glass slides and cultured cells grown on cell culture plastic, with a resolution close to 1 μm. The method exploits the phase information that is preserved in the interference between the acoustic wave reflected from the substrate surface and internal reflections from the acoustic lens. In practice, a stack of acoustic images are captured beginning with the acoustic focal point 4 μm above the substrate surface and moving down in 0.1 μm increments. Scanning parameters, such as acoustic wave frequency and gate position, were adjusted to obtain optimal phase and lateral resolution. The data were processed offline to extract the phase information with the contribution of any inclination in the substrate removed prior to the calculation of sound speed. Here, we apply this approach to both skin sections and fibroblast cells, and compare our data with the V(f) (voltage vs frequency) method that has previously been used for characterisation of soft tissues and cells. Compared with the V(f) method, the MPLA method not only reduces signal noise but can be implemented without making a priori assumptions with regards to tissue or cell parameters. PMID:22547273

  16. Analysis of Nonlinear Insertion Loss of Hearing Protection Devices using an Acoustic Test Fixture (United States)


    participant, usually attached to some sort of insert earplug. For ATF measurements, the microphone is located inside a simulated ear installed in a...USAARL Report No. 2016-05 Analysis of Nonlinear Insertion Loss of Hearing Protection Devices using an Acoustic Test Fixture By Robert Williams1...9 Third-octave band insertion loss

  17. Vibro-Acoustic Numerical Analysis for the Chain Cover of a Car Engine

    National Research Council Canada - National Science Library

    Enrico Armentani; Raffaele Sepe; Antonio Parente; Mauro Pirelli


    In this work, a vibro-acoustic numerical and experimental analysis was carried out for the chain cover of a low powered four-cylinder four-stroke diesel engine, belonging to the FPT (FCA Power Train) family called SDE (Small Diesel Engine...

  18. Integrating acoustic analysis in the architectural design process using parametric modelling

    DEFF Research Database (Denmark)

    Peters, Brady


    This paper discusses how parametric modeling techniques can be used to provide architectural designers with a better understanding of the acoustic performance of their designs and provide acoustic engineers with models that can be analyzed using computational acoustic analysis software. Architects...... provide a method by which architects and engineers can work together more efficiently and communicate better. This research is illustrated through the design of an architectural project, a new school in Copenhagen, Denmark by JJW Architects, where parametric modeling techniques have been used in different...... are increasingly using parametric modeling techniques in their design processes to allow the exploration of large numbers of design options using multiple criteria. Parametric modeling software can be performance-driven and sound has the potential to become one of these performance-driven dimensions. This can...

  19. Nonlinear response analysis and experimental verification for thin-walled plates to thermal-acoustic loads

    Directory of Open Access Journals (Sweden)

    Yundong SHA


    Full Text Available For large deflection strongly nonlinear response problem of thin-walled structure to thermal-acoustic load, thermal-acoustic excitation test and corresponding simulation analysis for clamped metallic thin-walled plate have been implemented. Comparing calculated values with experimental values shows the consistency and verifies the effectiveness of calculation method and model for thin-walled plate subjected to thermal-acoustic load. Then this paper further completes dynamic response calculation for the cross reinforcement plate under different thermal-acoustic load combinations. Based on the obtained time-domain displacement response, analyses about structure vibration forms are mainly focused on three typical motions of post-buckled plate, indicating that the relative strength between thermal load and acoustic load determines jump forms of plate. The Probability spectrum Density Functions (PDF of displacement response were drawn and analyzed by employing statistical analysis method, and it clearly shows that the PDF of post-buckled plate exhibits bimodal phenomena. Then the Power Spectral Density (PSD functions were used to analyze variations of response frequencies and corresponding peaks with the increase of temperatures, as well as how softening and hardening areas of the plate are determined. In the last section, this paper discusses the change laws of tensile stress and compressive stress in pre/post buckling areas, and gives the reasons for N glyph trend of the stress Root Mean Square (RMS. Keywords: Buckling, Experimental verification, Nonlinear response, Power spectral density, Probability spectrum density, Snap-through, Thermal-acoustic load, Thin-walled structure

  20. Study for Identification of Beneficial Uses of Space (BUS). Volume 2: Technical report. Book 4: Development and business analysis of space processed surface acoustic wave devices (United States)


    Preliminary development plans, analysis of required R and D and production resources, the costs of such resources, and, finally, the potential profitability of a commercial space processing opportunity for the production of very high frequency surface acoustic wave devices are presented.

  1. The Separation of Blood Components Using Standing Surface Acoustic Waves (SSAWs Microfluidic Devices: Analysis and Simulation

    Directory of Open Access Journals (Sweden)

    Ahmed M. Soliman


    Full Text Available The separation of blood components (WBCs, RBCs, and platelets is important for medical applications. Recently, standing surface acoustic wave (SSAW microfluidic devices are used for the separation of particles. In this paper, the design analysis of SSAW microfluidics is presented. Also, the analysis of SSAW force with Rayleigh angle effect and its attenuation in liquid-loaded substrate, viscous drag force, hydrodynamic force, and diffusion force are explained and analyzed. The analyses are provided for selecting the piezoelectric material, width of the main microchannel, working area of SAW, wavelength, minimum input power required for the separation process, and widths of outlet collecting microchannels. The design analysis of SSAW microfluidics is provided for determining the minimum input power required for the separation process with appropriated the displacement contrast of the particles.The analyses are applied for simulation the separation of blood components. The piezoelectric material, width of the main microchannel, working area of SAW, wavelength, and minimum input power required for the separation process are selected as LiNbO3, 120 μm, 1.08 mm2, 300 μm, 371 mW. The results are compared to other published results. The results of these simulations achieve minimum power consumption, less complicated setup, and high collecting efficiency. All simulation programs are built by MATLAB.

  2. Vibroacoustic analysis and experimental validation of the structural responses of NASA Mars Exploration Rover spacecraft due to acoustic launch load (United States)

    Hwang, H. J.


    Structural responses of a spacecraft during liftoff are dominated by the intense acoustic pressure field imping on the exterior of the launch vehicle. Statistical Energy Analysis model of the NASA Mars Exploration Rover spacecraft has been developed and the SEA model was analyzed to predict vibroacoustic responses of the spacecraft under the diffuse acoustic loading condition.

  3. Emotional prosody expression in acoustic analysis in patients with right hemisphere ischemic stroke. (United States)

    Guranski, Konstanty; Podemski, Ryszard


    The role of the right cerebral hemisphere in nonverbal speech activities remains controversial. Most research supports the dominant role of the right hemisphere in the control of emotional prosody. There has been significant discussion of the participation of cortical and subcortical structures of the right hemisphere in the processing of various acoustic speech parameters. The aim of this study was an acoustic analysis of the speech parameters during emotional expression in right hemisphere ischemic strokes with an attempt to reference the results to lesion location. Acoustic speech analysis was conducted on forty-six right-handed patients with right-middle cerebral artery stroke, together with 34 age-matched people in the control group. We compared the results of acoustic studies between patients with varying infarct locations and the control group. Variations in fundamental frequency during verbal expression of joy, anger and sadness were significantly smaller in the patient group than in the control group. Cortical lesion caused more restrictions in fundamental frequency variation in the expression of joy and a lower voice intensity in expressions of anger and joy compared to those patients with subcortical lesions. Cortical lesion was associated with a more impaired expression of emotional prosody than subcortical lesion. The results indicate the leading role of the cortical structures of the right hemisphere in the expression of emotional prosody. Copyright © 2015 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  4. Synergy of seismic, acoustic, and video signals in blast analysis

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.P. [Southern Methodist Univ., Dallas, TX (United States); Stump, B.W. [Los Alamos National Lab., NM (United States); Weigand, J. [Vibronics Inc. (United States)


    The range of mining applications from hard rock quarrying to coal exposure to mineral recovery leads to a great variety of blasting practices. A common characteristic of many of the sources is that they are detonated at or near the earth`s surface and thus can be recorded by camera or video. Although the primary interest is in the seismic waveforms that these blasts generate, the visual observations of the blasts provide important constraints that can be applied to the physical interpretation of the seismic source function. In particular, high speed images can provide information on detonation times of individuals charges, the timing and amount of mass movement during the blasting process and, in some instances, evidence of wave propagation away from the source. All of these characteristics can be valuable in interpreting the equivalent seismic source function for a set of mine explosions and quantifying the relative importance of the different processes. This paper documents work done at the Los Alamos National Laboratory and Southern Methodist University to take standard Hi-8 video of mine blasts, recover digital images from them, and combine them with ground motion records for interpretation. The steps in the data acquisition, processing, display, and interpretation are outlined. The authors conclude that the combination of video with seismic and acoustic signals can be a powerful diagnostic tool for the study of blasting techniques and seismology. A low cost system for generating similar diagnostics using consumer-grade video camera and direct-to-disk video hardware is proposed. Application is to verification of the Comprehensive Test Ban Treaty.

  5. An analysis of the feasibility of using the Hsu-Nielsen calibration method in systems for measuring acoustic emission from partial discharges (United States)

    Skubis, Jerzy; Ranachowski, Zbigniew; Boczar, T.; Lorenc, M.

    The subject of this article is an analysis of the feasibility of using the Hsu-Nielsen calibration method to measure acoustic emission from partial discharges. In the first part of the article the authors present a concept and method of calibration which makes it possible to calibrate the measuring circuit properly. The second part contains the results of experiments which involved calibrating two different acoustic emission analyzers, namely the Izold and the Demy 34 models. In conclusion the authors discuss the practical requirements for proper calibration of the systems in a technical environment.

  6. Evaluation of marginal failures of dental composite restorations by acoustic emission analysis. (United States)

    Gu, Ja-Uk; Choi, Nak-Sam


    In this study, a nondestructive method based on acoustic emission (AE) analysis was developed to evaluate the marginal failure states of dental composite restorations. Three types of ring-shaped substrates, which were modeled after a Class I cavity, were prepared from polymethyl methacrylate, stainless steel, and human molar teeth. A bonding agent and a composite resin were applied to the ring-shaped substrates and cured by light exposure. At each time-interval measurement, the tooth substrate presented a higher number of AE hits than polymethyl methacrylate and steel substrates. Marginal disintegration estimations derived from cumulative AE hits and cumulative AE energy parameters showed that a signification portion of marginal gap formation was already realized within 1 min at the initial light-curing stage. Estimation based on cumulative AE energy gave a higher level of marginal failure than that based on AE hits. It was concluded that the AE analysis method developed in this study was a viable approach in predicting the clinical survival of dental composite restorations efficiently within a short test period.

  7. Wavelet Analysis of Acoustic Emissions during Tensile Test of Carbon Fibre Reinforced Polymer Composites (United States)

    Świt, Grzegorz; Adamczak, Anna; Krampikowska, Aleksandra


    The increase of the interest in polymer composites in technology and in people’s everyday lives has been noticed in the recent years. Producing new materials with polymer matrix of particular properties that cannot be achieved by traditional construction materials contributed to high interest in fibre composite materials. However, a wider use of these materials is limited because of the lack of detailed knowledge about their properties and behaviour in various conditions of exposure under load. Mechanical degradation of polymer composites, which is caused by prolonged permanent loads, is connected with the changes of the material structure that are local or that include the whole volume of the element’s body. These changes are in the form of various types of discontinuity, including: deboning, matrix and fibers cracks and delamination. The article presents the example of the application of acoustic emission method based on the analysis of the waves through the use of wavelet analysis for the evaluation of the progress of the destructive processes and the level of the degradation of composite tapes that were subject to tensile testing.

  8. Room acoustic analysis of blower unit and noise control plan in the typical steel industry

    Directory of Open Access Journals (Sweden)


    Full Text Available Introduction: In the steel industry,air blowers used to supply compressed air are considered as sources of annoying noise. This study aims to acoustics analysis of theairblower workroomand sound source characteristics in order to present noise controlmeasuresinthe steel industry. .Material and Method: Measurement of noiselevel and its frequency analysis was performed usingsound levelmetermodelof CASELLA-Cell.450. Distribution of noise level in the investigated workroom in form of noise map was provided using Surfer software. In addition, acoustic analysis of workroom and control room was performed in view point of soundabsorption andinsulation. Redesignofdoor and window of controlroom and installation of soundabsorbing materialson theceiling of the workroom were proposed and the efficiency of these interventionswasestimated. .Result: The totalsound pressurelevelin the blower workroom was 95.4 dB(L and the dominant frequency was 2000Hz. Sound pressure level inside the room control was 80.1dB(A. The average absorption coefficient and reverberation time in the blower workroom was estimated equal to 0.082 Sab.m2 and 3.9 seconds respectively. These value in control room was 0.04 Sab.m2 and 3/4 seconds respectively. In control room, sound transmission loss between the two parts of the wall dividing was 13.7 dB(A. The average of noise dose in blower operators was 230%. With the installation of sound absorber on ceiling of workroom, average of absorption coefficient can increase to 0.33 Sab.m2 and sound transmission loss of the new designed door and window was estimated equal to 20dB. . Conclusion: The main cause of noise leakage in the control room was insufficient insulation properties of door and windows. By replacing the door and window and installation of sound absorbing on ceiling of workroom, the noise dose can reduce to 49.6%. New Improved door and window of control room can reduce noise dose to 69.65% solely.

  9. Acoustic and articulatory analysis of French vowels produced by congenitally blind adults and sighted adults. (United States)

    Ménard, Lucie; Toupin, Corinne; Baum, Shari R; Drouin, Serge; Aubin, Jérôme; Tiede, Mark


    In a previous paper [Ménard et al., J. Acoust. Soc. Am. 126, 1406-1414 (2009)], it was demonstrated that, despite enhanced auditory discrimination abilities for synthesized vowels, blind adult French speakers produced vowels that were closer together in the acoustic space than those produced by sighted adult French speakers, suggesting finer control of speech production in the sighted speakers. The goal of the present study is to further investigate the articulatory effects of visual deprivation on vowels produced by 11 blind and 11 sighted adult French speakers. Synchronous ultrasound, acoustic, and video recordings of the participants articulating the ten French oral vowels were made. Results show that sighted speakers produce vowels that are spaced significantly farther apart in the acoustic vowel space than blind speakers. Furthermore, blind speakers use smaller differences in lip protrusion but larger differences in tongue position and shape than their sighted peers to produce rounding and place of articulation contrasts. Trade-offs between lip and tongue positions were examined. Results are discussed in the light of the perception-for-action control theory.

  10. Mobility power flow analysis of an L-shaped plate structure subjected to acoustic excitation (United States)

    Cuschieri, J. M.


    An analytical investigation based on the Mobility Power Flow method is presented for the determination of the vibrational response and power flow for two coupled flat plate structures in an L-shaped configuration, subjected to acoustical excitation. The principle of the mobility power flow method consists of dividing the global structure into a series of subsystems coupled together using mobility functions. Each separate subsystem is analyzed independently to determine the structural mobility functions for the junction and excitation locations. The mobility functions, together with the characteristics of the junction between the subsystems, are then used to determine the response of the global structure and the power flow. In the coupled plate structure considered here, mobility power flow expressions are derived for excitation by an incident acoustic plane wave. In this case, the forces (acoustic pressures) acting on the structure are dependent on the response of the structure because of the scattered pressure component. The interaction between the structure and the fluid leads to the derivation of a corrected mode shape for the plates' normal surface velocity and also for the structure mobility functions. The determination of the scattered pressure components in the expressions for the power flow represents an additional component in the power flow balance for the source plate and the receiver plate. This component represents the radiated acoustical power from the plate structure.

  11. Vibro-Acoustic Numerical Analysis for the Chain Cover of a Car Engine

    Directory of Open Access Journals (Sweden)

    Enrico Armentani


    Full Text Available In this work, a vibro-acoustic numerical and experimental analysis was carried out for the chain cover of a low powered four-cylinder four-stroke diesel engine, belonging to the FPT (FCA Power Train family called SDE (Small Diesel Engine. By applying a methodology used in the acoustic optimization of new FPT engine components, firstly a finite element model (FEM of the engine was defined, then a vibration analysis was performed for the whole engine (modal analysis, and finally a forced response analysis was developed for the only chain cover (separated from the overall engine. The boundary conditions applied to the chain cover were the accelerations experimentally measured by accelerometers located at the points of connection among chain cover, head cover, and crankcase. Subsequently, a boundary element (BE model of the only chain cover was realized to determine the chain cover noise emission, starting from the previously calculated structural vibrations. The numerical vibro-acoustic outcomes were compared with those experimentally observed, obtaining a good correlation. All the information thus obtained allowed the identification of those critical areas, in terms of noise generation, in which to undertake necessary improvements.

  12. Analysis of Field Data to Describe the Effect of Context (Acoustic and Non-Acoustic Factors on Urban Soundscapes

    Directory of Open Access Journals (Sweden)

    Karmele Herranz-Pascual


    Full Text Available The need to improve acoustic environments in our cities has led to increased interest in correcting or minimising noise pollution in urban environments, something that has been associated with the resurgence of the soundscape approach. This line of research highlights the importance of context in the perception of acoustic environments. Despite this, few studies consider together a wide number of variables relating to the context, and analyse the relative importance of each. The purpose of this paper is therefore to identify the acoustic and non-acoustic characteristics of a place (context that influence an individual’s perception of the sound environment and the relative importance of these factors in soundscape. The aim is to continue advancing in the definition of an acoustic comfort indicator for urban places. The data used here were collected in various soundscape campaigns carried out by Tecnalia in Bilbao (Spain between 2011 and 2014. These studies involved 534 evaluations of 10 different places. The results indicate that many diverse contextual factors determine soundscape, the most important being the congruence between soundscape and landscape. The limitations of the findings and suggestions for further research are also discussed.

  13. Aquatic Acoustic Metrics Interface Utility for Underwater Sound Monitoring and Analysis

    Directory of Open Access Journals (Sweden)

    Thomas J. Carlson


    Full Text Available Fishes and marine mammals may suffer a range of potential effects from exposure to intense underwater sound generated by anthropogenic activities such as pile driving, shipping, sonars, and underwater blasting. Several underwater sound recording (USR devices have been built to acquire samples of the underwater sound generated by anthropogenic activities. Software becomes indispensable for processing and analyzing the audio files recorded by these USRs. In this paper, we provide a detailed description of a new software package, the Aquatic Acoustic Metrics Interface (AAMI, specifically designed for analysis of underwater sound recordings to provide data in metrics that facilitate evaluation of the potential impacts of the sound on aquatic animals. In addition to the basic functions, such as loading and editing audio files recorded by USRs and batch processing of sound files, the software utilizes recording system calibration data to compute important parameters in physical units. The software also facilitates comparison of the noise sound sample metrics with biological measures such as audiograms of the sensitivity of aquatic animals to the sound, integrating various components into a single analytical frame. The features of the AAMI software are discussed, and several case studies are presented to illustrate its functionality.

  14. Efficient blind dereverberation and echo cancellation based on independent component analysis for actual acoustic signals. (United States)

    Takeda, Ryu; Nakadai, Kazuhiro; Takahashi, Toru; Komatani, Kazunori; Ogata, Tetsuya; Okuno, Hiroshi G


    This letter presents a new algorithm for blind dereverberation and echo cancellation based on independent component analysis (ICA) for actual acoustic signals. We focus on frequency domain ICA (FD-ICA) because its computational cost and speed of learning convergence are sufficiently reasonable for practical applications such as hands-free speech recognition. In applying conventional FD-ICA as a preprocessing of automatic speech recognition in noisy environments, one of the most critical problems is how to cope with reverberations. To extract a clean signal from the reverberant observation, we model the separation process in the short-time Fourier transform domain and apply the multiple input/output inverse-filtering theorem (MINT) to the FD-ICA separation model. A naive implementation of this method is computationally expensive, because its time complexity is the second order of reverberation time. Therefore, the main issue in dereverberation is to reduce the high computational cost of ICA. In this letter, we reduce the computational complexity to the linear order of the reverberation time by using two techniques: (1) a separation model based on the independence of delayed observed signals with MINT and (2) spatial sphering for preprocessing. Experiments show that the computational cost grows in proportion to the linear order of the reverberation time and that our method improves the word correctness of automatic speech recognition by 10 to 20 points in a RT₂₀= 670 ms reverberant environment.

  15. Detection and characterization of stainless steel SCC by the analysis of crack related acoustic emission. (United States)

    Kovač, Jaka; Legat, Andraž; Zajec, Bojan; Kosec, Tadeja; Govekar, Edvard


    In the paper the results of the acoustic emission (AE) based detection and characterization of stress-corrosion cracking (SCC) in stainless steel are presented. As supportive methods for AE interpretation, electrochemical noise, specimen elongation measurements, and digital imaging of the specimen surface were used. Based on the defined qualitative and quantitative time and power spectra characteristics of the AE bursts, a manual and an automatic procedure for the detection of crack related AE bursts were introduced. The results of the analysis of the crack related AE bursts indicate that the AE method is capable of detecting large scale cracks, where, apart from intergranular crack propagation, also some small ductile fractures occur. The sizes of the corresponding ductile fracture areas can be estimated based on a relative comparison of the energies of the detected AE bursts. It has also been shown that AE burst time and power spectra features can be successfully used for the automatic detection of SCC. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Aquatic acoustic metrics interface utility for underwater sound monitoring and analysis. (United States)

    Ren, Huiying; Halvorsen, Michele B; Deng, Zhiqun Daniel; Carlson, Thomas J


    Fishes and marine mammals may suffer a range of potential effects from exposure to intense underwater sound generated by anthropogenic activities such as pile driving, shipping, sonars, and underwater blasting. Several underwater sound recording (USR) devices have been built to acquire samples of the underwater sound generated by anthropogenic activities. Software becomes indispensable for processing and analyzing the audio files recorded by these USRs. In this paper, we provide a detailed description of a new software package, the Aquatic Acoustic Metrics Interface (AAMI), specifically designed for analysis of underwater sound recordings to provide data in metrics that facilitate evaluation of the potential impacts of the sound on aquatic animals. In addition to the basic functions, such as loading and editing audio files recorded by USRs and batch processing of sound files, the software utilizes recording system calibration data to compute important parameters in physical units. The software also facilitates comparison of the noise sound sample metrics with biological measures such as audiograms of the sensitivity of aquatic animals to the sound, integrating various components into a single analytical frame. The features of the AAMI software are discussed, and several case studies are presented to illustrate its functionality.

  17. Analysis of the Acoustic and Vibration Measurement in the Disintegration Process

    Directory of Open Access Journals (Sweden)

    Ľudmila Ušalová


    Full Text Available In the last thirty years there have been many developments in the use of acoustical and vibration measurement and their analysis for monitoring the condition of rotating machinery. These have been in three areas of interest the: detection of machinery pieces faults, the diagnosis and the prognosis. Of these areas, the diagnosis and prognosis still require an expert to determine what analyses to perform and to interpret the results. Currently much effort is being put into the automated fault diagnosis and prognosis. Major benefits come from the ability to predict with a reasonable accuracy how long a machine can safely operate (often a matter of several months from incipient faults are first detected. This article briefly summarizes selected signal processing methods, which are possible to be suggested for the vibroacoustical measurements evalution. These techniques are presented with a reference to their use in the rock disintegration process. Simultaneously, several cases are discussed where a great care must be taken in setting up input parameters or very misleading data would be produced.

  18. Analysis and Classification of Acoustic Emission Signals During Wood Drying Using the Principal Component Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ho Yang [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Ki Bok [Chungnam National University, Daejeon (Korea, Republic of)


    In this study, acoustic emission (AE) signals due to surface cracking and moisture movement in the flat-sawn boards of oak (Quercus Variablilis) during drying under the ambient conditions were analyzed and classified using the principal component analysis. The AE signals corresponding to surface cracking showed higher in peak amplitude and peak frequency, and shorter in rise time than those corresponding to moisture movement. To reduce the multicollinearity among AE features and to extract the significant AE parameters, correlation analysis was performed. Over 99% of the variance of AE parameters could be accounted for by the first to the fourth principal components. The classification feasibility and success rate were investigated in terms of two statistical classifiers having six independent variables (AE parameters) and six principal components. As a result, the statistical classifier having AE parameters showed the success rate of 70.0%. The statistical classifier having principal components showed the success rate of 87.5% which was considerably than that of the statistical classifier having AE parameters

  19. Responsive acoustic surfaces

    DEFF Research Database (Denmark)

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


    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....

  20. SIRAMIS : Preliminary analysis of acoustic and seismic ship signatures

    NARCIS (Netherlands)

    Fillinger, L.; Mantouka, A.; Jong, C.A.F. de; Gloza, I.; Sanchez, A.; Moya, E.; Schael, S.; Lennartsson, T.; Petit, G.; Fardal, R.; Hasenpflug, H.; Beckers, A.L.D.


    SIRAMIS is a project coordinated by the European Defence Agency standing for Signature Response Analysis on Multi Influence Sensors. As most of the international trade is carried out through marine routes, it is important to evaluate the vulnerability of the merchant vessel fleet to sea mines in

  1. Acoustic Analysis of Voice in Dysarthria following Stroke (United States)

    Wang, Yu-Tsai; Kent, Ray D.; Kent, Jane Finley; Duffy, Joseph R.; Thomas, Jack E.


    Although perceptual studies indicate the likelihood of voice disorders in persons with stroke, there have been few objective instrumental studies of voice dysfunction in dysarthria following stroke. This study reports automatic analysis of sustained vowel phonation for 61 speakers with stroke. The results show: (1) men with stroke and healthy…

  2. Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments

    Directory of Open Access Journals (Sweden)

    Angga Dwinovantyo


    Full Text Available The application of Acoustic Doppler Current Profiler (ADCP can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient (r 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.

  3. Throughput Analysis on 3-Dimensional Underwater Acoustic Network with One-Hop Mobile Relay. (United States)

    Zhong, Xuefeng; Chen, Fangjiong; Fan, Jiasheng; Guan, Quansheng; Ji, Fei; Yu, Hua


    Underwater acoustic communication network (UACN) has been considered as an essential infrastructure for ocean exploitation. Performance analysis of UACN is important in underwater acoustic network deployment and management. In this paper, we analyze the network throughput of three-dimensional randomly deployed transmitter-receiver pairs. Due to the long delay of acoustic channels, complicated networking protocols with heavy signaling overhead may not be appropriate. In this paper, we consider only one-hop or two-hop transmission, to save the signaling cost. That is, we assume the transmitter sends the data packet to the receiver by one-hop direct transmission, or by two-hop transmission via mobile relays. We derive the closed-form formulation of packet delivery rate with respect to the transmission delay and the number of transmitter-receiver pairs. The correctness of the derivation results are verified by computer simulations. Our analysis indicates how to obtain a precise tradeoff between the delay constraint and the network capacity.

  4. Acoustic Analysis and Design of the E-STA MSA Simulator (United States)

    Bittinger, Samantha A.


    The Orion European Service Module Structural Test Article (E-STA) Acoustic Test was completed in May 2016 to verify that the European Service Module (ESM) can withstand qualification acoustic environments. The test article required an aft closeout to simulate the Multi-Purpose Crew Vehicle (MPCV) Stage Adapter (MSA) cavity, however, the flight MSA design was too cost-prohibitive to build. NASA Glenn Research Center (GRC) had 6 months to design an MSA Simulator that could recreate the qualification prediction MSA cavity sound pressure level to within a reasonable tolerance. This paper summarizes the design and analysis process to arrive at a design for the MSA Simulator, and then compares its performance to the final prediction models created prior to test.

  5. Hypernasal Speech Detection by Acoustic Analysis of Unvoiced Plosive Consonants

    Directory of Open Access Journals (Sweden)

    Alexander Sepúlveda-Sepúlveda


    Full Text Available People with a defective velopharyngeal mechanism speak with abnormal nasal resonance (hypernasal speech. Voice analysis methods for hypernasality detection commonly use vowels and nasalized vowels. However to obtain a more general assessment of this abnormality it is necessary to analyze stops and fricatives. This study describes a method with high generalization capability for hypernasality detection analyzing unvoiced Spanish stop consonants. The importance of phoneme-by-phoneme analysis is shown, in contrast with whole word parametrization which includes irrelevant segments from the classification point of view. Parameters that correlate the imprints of Velopharyngeal Incompetence (VPI over voiceless stop consonants were used in the feature estimation stage. Classification was carried out using a Support Vector Machine (SVM, including the Rademacher complexity model with the aim of increasing the generalization capability. Performances of 95.2% and 92.7% were obtained in the processing and verification stages for a repeated cross-validation classifier evaluation.

  6. Comparison of Estimation Techniques for Vibro-Acoustic Transfer Path Analysis

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo França Padilha


    Full Text Available Vibro-acoustic Transfer Path Analysis (TPA is a tool to evaluate the contribution of different energy propagation paths between a source and a receiver, linked to each other by a number of connections. TPA is typically used to quantify and rank the relative importance of these paths in a given frequency band, determining the most significant one to the receiver. Basically, two quantities have to be determined for TPA: the operational forces at each transfer path and the Frequency Response Functions (FRF of these paths. The FRF are obtained either experimentally or analytically, and the influence of the mechanical impedance of the source can be taken into account or not. The operational forces can be directly obtained from measurements using force transducers or indirectly estimated from auxiliary response measurements. Two methods to obtain the operational forces indirectly – the Complex Stiffness Method (CSM and the Matrix Inversion Method (MIM – associated with two possible configurations to determine the FRF – including and excluding the source impedance – are presented and discussed in this paper. The effect of weak and strong coupling among the paths is also commented considering the techniques previously presented. The main conclusion is that, with the source removed, CSM gives more accurate results. On the other hand, with the source present, MIM is preferable. In the latter case, CSM should be used only if there is a high impedance mismatch between the source and the receiver. Both methods are not affected by a higher or lower degree of coupling among the transfer paths.

  7. Near-Field Acoustic Power Level Analysis of F31/A31 Open Rotor Model at Simulated Cruise Conditions, Technical Report II (United States)

    Sree, Dave


    Near-field acoustic power level analysis of F31A31 open rotor model has been performed to determine its noise characteristics at simulated cruise flight conditions. The non-proprietary parts of the test data obtained from experiments in the 8x6 supersonic wind tunnel were provided by NASA-Glenn Research Center. The tone and broadband components of total noise have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, freestream Mach number, and input shaft power, with different blade-pitch setting angles at simulated cruise flight conditions, are presented and discussed. Empirical equations relating models acoustic power level and input shaft power have been developed. The near-field acoustic efficiency of the model at simulated cruise conditions is also determined. It is hoped that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.

  8. Homogenization-based interval analysis for structural-acoustic problem involving periodical composites and multi-scale uncertain-but-bounded parameters. (United States)

    Chen, Ning; Yu, Dejie; Xia, Baizhan; Liu, Jian; Ma, Zhengdong


    This paper presents a homogenization-based interval analysis method for the prediction of coupled structural-acoustic systems involving periodical composites and multi-scale uncertain-but-bounded parameters. In the structural-acoustic system, the macro plate structure is assumed to be composed of a periodically uniform microstructure. The equivalent macro material properties of the microstructure are computed using the homogenization method. By integrating the first-order Taylor expansion interval analysis method with the homogenization-based finite element method, a homogenization-based interval finite element method (HIFEM) is developed to solve a periodical composite structural-acoustic system with multi-scale uncertain-but-bounded parameters. The corresponding formulations of the HIFEM are deduced. A subinterval technique is also introduced into the HIFEM for higher accuracy. Numerical examples of a hexahedral box and an automobile passenger compartment are given to demonstrate the efficiency of the presented method for a periodical composite structural-acoustic system with multi-scale uncertain-but-bounded parameters.

  9. Acoustic analysis of musical intervals in modern Byzantine Chant scales. (United States)

    Delviniotis, Dimitrios; Kouroupetroglou, Georgios; Theodoridis, Sergios


    The goal of this work is to investigate experimentally the music intervals in modern Byzantine Chant performance and to compare the obtained results with the equal temperament scales introduced by the Patriarchal Music Committee (PMC). Current measurements resulted from pressure and electroglottographic recordings of 13 famous chanters singing scales of all the music genera. The scales' microintervals were derived after pitch detection based on autocorrelation, cepstrum, and harmonic product spectrum analysis. The microintervallic differences between the experimental values and the PMC's ones were statistically analyzed indicating large deviation of the mean values and the standard deviations. Significant interaction effects were identified among some genera and between ascending and descending scale directions.

  10. Prediction of Equipment Failures by Acoustical Signature Analysis - Phase 1 (United States)


    are present. Depot MAIDS is a computerized test system used in instrumented dynamometer cells at Letterkenny Army Depot. Many pressure, temperature...and a portable dynamometer are used so that the unit is mobile. 2 -.. STEAP-MT-G SUBJECT: Final Letter Report of Phase I of Prediction of Equipment...tree structure is that of clustering. It is desirable to define the smaller subclasses (e.g. sticking valves and loose wrist pins) to be grouped together

  11. Measurements and analysis of acoustic backscattering by elastic cubes and irregular polyhedra

    DEFF Research Database (Denmark)

    Thorne, P D; Sun, S; Zhang, J


    Underwater acoustic studies of backscattering by submerged targets have generally focused on bodies with spherical and cylindrical symmetry. However, there are interests in scattering by objects which may be characterized by more angular features, with surfaces that tend to be composed of facets...... and edges. To investigate the scattering properties of such bodies, the backscattering by a number of elastic cubes, and irregularly shaped polyhedra, have been studied. Data were collected by measuring the band limited impulse response of the scatterers, using a broadband transducer, which operated...... as a transceiver, both transmitting and receiving signals. To present the scattering measurements nondimensionally a form function definition has been employed to normalize the backscattered signals. The normalized frequency has been expressed as ka, where k is the acoustic wave number, and a is a characteristic...

  12. Review and analysis of the DNW/Model 360 rotor acoustic data base (United States)

    Zinner, R. A.; Boxwell, D. A.; Spencer, R. H.


    A comprehensive model rotor aeroacoustic data base was collected in a large anechoic wind tunnel in 1986. Twenty-six microphones were positioned around the azimuth to collect acoustic data for approximately 150 different test conditions. A dynamically scaled, blade-pressure-instrumented model of the forward rotor of the BH360 helicopter simultaneously provided blade pressures for correlation with the acoustic data. High-speed impulsive noise, blade-vortex interaction noise, low-frequency noise, and broadband noise were all captured in this extensive data base. Trends are presentes for each noise source, with important parametric variations. The purpose of this paper is to introduce this data base and illustrate its potential for predictive code validation.

  13. Vibro-Acoustic Response Analysis Of LAUNCH VEHICLE INTER-STAGE

    Directory of Open Access Journals (Sweden)

    Anjana Mariam Alex


    Full Text Available Right from lift-off launch vehicles are subjected to extreme dynamic pressure aero and structure borne excitations. Inter-stage is fundamental to the vehicle as it houses the different control equipments actuators sensors motors and avionic packages. This paper involves the creation of two different models so as to study the correlation using two approaches Finite Element method and Hybrid Method involving Statistical Energy Analysis and Finite Element Analysis. The correlation of the response obtained on the Inter-stage from an acoustic ground test to that from the analytical test results carried out with VA One is also addressed in this paper.

  14. Acoustic Emission Analysis During High Velocity Accelerated Wear Test (United States)

    Peck, P. R.; Kono, R. N.; Jhon, M. S.; Karis, T. E.

    The phenomena taking place at the slider-disk interface are a topic of long term fundamental interest as well as practical significance. A novel accelerated wear tester for studying the slider in close proximity to the disk at high velocity is described. This incorporates a pneumatic loading cylinder on the suspension to increase the load while the slider is flying. Slider-disk interaction is detected by accelerometers mounted on the suspension arm. As the flying height is lowered, the resonant vibration of the arm is recorded to characterize the interface. Preliminary results showing the effect of disk velocity and roughness on the vibration-flying height curve are presented along with qualitative interpretation.

  15. Assessment of effectiveness of acoustic analysis of voice for monitoring the evolution of vocal nodules after vocal treatment. (United States)

    Halawa, Wasim Elhendi; Rodríguez Fernández Freire, Antonio; Muñoz, Irene Vázquez; Pérez, Sofía Santos


    In the present study, we report the results of acoustic analysis of voice in 97 patients diagnosed with vocal nodules before and after the vocal logopedic treatment, to evaluate its effectiveness in monitoring the evolution. We analyzed five parameters: the mean fundamental frequency (F0) and its standard deviation, jitter, shimmer, and normalized noise energy (NNE). Our results indicate that most patients showed a reduction of fundamental frequency, an increase of perturbation (jitter and shimmer), and an increase of NNE before the treatment. We did not find any statistically significant relationship between previous values of the five parameters analyzed and the clinical course. We did not find significant differences between the two groups (with and without clinical improvement) in the evolution of any of the five parameters, although these differences were greater in the case of jitter. We conclude that the acoustic analysis of voice can be useful as a complementary tool in the diagnosis of vocal nodules, but the parameter values analyzed before treatment did not correlate with the clinical course and we believe that its usefulness in the evaluation of results after the vocal treatment is limited.

  16. An Aquatic Acoustic Metrics Interface Utility for Underwater Sound Monitoring and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Huiying; Halvorsen, Michele B.; Deng, Zhiqun; Carlson, Thomas J.


    Fishes and other marine mammals suffer a range of potential effects from intense sound sources generated by anthropogenic underwater processes such as pile driving, shipping, sonars, and underwater blasting. Several underwater sound recording devices (USR) were built to monitor the acoustic sound pressure waves generated by those anthropogenic underwater activities, so the relevant processing software becomes indispensable for analyzing the audio files recorded by these USRs. However, existing software packages did not meet performance and flexibility requirements. In this paper, we provide a detailed description of a new software package, named Aquatic Acoustic Metrics Interface (AAMI), which is a Graphical User Interface (GUI) designed for underwater sound monitoring and analysis. In addition to the general functions, such as loading and editing audio files recorded by USRs, the software can compute a series of acoustic metrics in physical units, monitor the sound's influence on fish hearing according to audiograms from different species of fishes and marine mammals, and batch process the sound files. The detailed applications of the software AAMI will be discussed along with several test case scenarios to illustrate its functionality.

  17. A note on acoustic analysis of dairy calves’ vocalizations at 1 day after separation from dam

    Directory of Open Access Journals (Sweden)

    Doo Hwan Kim


    Full Text Available The vocalizations of animals are very useful in assessing an emotional state and welfare because they involve information about various emotions. Hence, the findings of the acoustic features of vocalization can be used to improve the productivity and welfare of animals. This study was conducted to analyse the vocalizations of dairy calves separated from the dam. At 6 days after birth, 12 dairy calves were moved into an individual calf pen (3.0m×2.0m bedded with sawdust and straw. One and a half litres of whole milk were fed twice daily and free access to water was allowed. The calves’ vocalizations were divided into humming vocalizations (HVs: low continuous calls without tone changed, semi-humming vocalizations (SHVs: low continuous calls with tone changed, and general vocalizations (GVs. These vocalizations were classified, based on the shapes of waveforms and spectrograms. Differences in the duration, fundamental frequency, intensity, and formants among the classified vocalizations were found (P<0.0001. Acoustic parameters except intensity and 3rd formant were not different between HVs and SHVs. These results suggest that vocalization analysis could be a useful tool in assessing the emotions of calves. Acoustic parameters are also useful in classifying vocalizations. Also, intensity and 3rd formant are advantageous in distinguishing HVs and SHVs.

  18. A comprehensive strategy for the analysis of acoustic compressibility and optical deformability on single cells (United States)

    Yang, Tie; Bragheri, Francesca; Nava, Giovanni; Chiodi, Ilaria; Mondello, Chiara; Osellame, Roberto; Berg-Sørensen, Kirstine; Cristiani, Ilaria; Minzioni, Paolo


    We realized an integrated microfluidic chip that allows measuring both optical deformability and acoustic compressibility on single cells, by optical stretching and acoustophoresis experiments respectively. Additionally, we propose a measurement protocol that allows evaluating the experimental apparatus parameters before performing the cell-characterization experiments, including a non-destructive method to characterize the optical force distribution inside the microchannel. The chip was used to study important cell-mechanics parameters in two human breast cancer cell lines, MCF7 and MDA-MB231. Results indicate that MDA-MB231 has both higher acoustic compressibility and higher optical deformability than MCF7, but statistical analysis shows that optical deformability and acoustic compressibility are not correlated parameters. This result suggests the possibility to use them to analyze the response of different cellular structures. We also demonstrate that it is possible to perform both measurements on a single cell, and that the order of the two experiments does not affect the retrieved values. PMID:27040456

  19. Acoustic data analysis and scenario over watch from an aerostat at the NATO SET-153 field experiment (United States)

    Reiff, Christian; Scanlon, Michael


    The purpose of the NATO SET-153 field experiment was to provide an opportunity to demonstrate multiple sensor technologies in an urban environment and determine integration capabilities for future development. The Army Research Laboratory (ARL) experimental aerostat was used primarily as a persistent over watch capability as a substitute for a UAV. Continuous video was recorded on the aerostat and segments of video were captured of the scenarios on the ground that the camera was following manually. Some of the segments showing scenario activities will be presented. The captured pictures and video frames have telemetry in the headers that provides the UTM time and the Inertial Navigation System (INS) GPS location and the inertial roll, pitch, and yaw as well as the camera gimbal pan and tilt angles. The timing is useful to synchronize the images with the scenario events providing activity ground truth. The INS, GPS, and camera gimbal angle values can be used with the acoustic solution for the location of a sound source to determine the relative accuracy of the solution if the camera is pointed at the sound source. This method will be confirmed by the use of a propane cannon whose GPS location is logged. During the field experiment, other interesting acoustic events such as vehicle convoys, platoon level firefights with vehicles using blanks, and a UAV helicopter were recorded and will be presented in a quick analysis.

  20. Presentation

    Directory of Open Access Journals (Sweden)

    Eduardo Vicente


    Full Text Available In the present edition of Significação – Scientific Journal for Audiovisual Culture and in the others to follow something new is brought: the presence of thematic dossiers which are to be organized by invited scholars. The appointed subject for the very first one of them was Radio and the invited scholar, Eduardo Vicente, professor at the Graduate Course in Audiovisual and at the Postgraduate Program in Audiovisual Media and Processes of the School of Communication and Arts of the University of São Paulo (ECA-USP. Entitled Radio Beyond Borders the dossier gathers six articles and the intention of reuniting works on the perspectives of usage of such media as much as on the new possibilities of aesthetical experimenting being build up for it, especially considering the new digital technologies and technological convergences. It also intends to present works with original theoretical approach and original reflections able to reset the way we look at what is today already a centennial media. Having broadened the meaning of “beyond borders”, four foreign authors were invited to join the dossier. This is the first time they are being published in this country and so, in all cases, the articles where either written or translated into Portuguese.The dossier begins with “Radio is dead…Long live to the sound”, which is the transcription of a thought provoking lecture given by Armand Balsebre (Autonomous University of Barcelona – one of the most influential authors in the world on the Radio study field. It addresses the challenges such media is to face so that it can become “a new sound media, in the context of a new soundscape or sound-sphere, for the new listeners”. Andrew Dubber (Birmingham City University regarding the challenges posed by a Digital Era argues for a theoretical approach in radio studies which can consider a Media Ecology. The author understands the form and discourse of radio as a negotiation of affordances and

  1. Perception of Male Caller Identity in Koalas (Phascolarctos cinereus): Acoustic Analysis and Playback Experiments (United States)

    Charlton, Benjamin D.; Ellis, William A. H.; McKinnon, Allan J.; Brumm, Jacqui; Nilsson, Karen; Fitch, W. Tecumseh


    The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels. PMID:21633499

  2. Perception of male caller identity in Koalas (Phascolarctos cinereus: acoustic analysis and playback experiments.

    Directory of Open Access Journals (Sweden)

    Benjamin D Charlton

    Full Text Available The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels.

  3. An Experimental Introduction to Acoustics (United States)

    Black, Andy Nicholas; Magruder, Robert H.


    Learning and understanding physics requires more than studying physics texts. It requires doing physics. Doing research is a key opportunity for students to connect physical principles with their everyday experience. A powerful way to introduce students to research and technique is through subjects in which they might find interest. Presented is an experiment that serves to introduce an advanced undergraduate or high school student to conducting research in acoustics via an experiment involving a standard dreadnought acoustic guitar, recording industry-related equipment, and relevant industrial analysis software. This experimental process is applicable to a wide range of acoustical topics including both acoustic and electric instruments. Also, the student has a hands-on experience with relevant audio engineering technology to study physical principles.

  4. Acoustic and temporal analysis of speech: A potential biomarker for schizophrenia.

    LENUS (Irish Health Repository)

    Rapcan, Viliam


    Currently, there are no established objective biomarkers for the diagnosis or monitoring of schizophrenia. It has been previously reported that there are notable qualitative differences in the speech of schizophrenics. The objective of this study was to determine whether a quantitative acoustic and temporal analysis of speech may be a potential biomarker for schizophrenia. In this study, 39 schizophrenic patients and 18 controls were digitally recorded reading aloud an emotionally neutral text passage from a children\\'s story. Temporal, energy and vocal pitch features were automatically extracted from the recordings. A classifier based on linear discriminant analysis was employed to differentiate between controls and schizophrenic subjects. Processing the recordings with the algorithm developed demonstrated that it is possible to differentiate schizophrenic patients and controls with a classification accuracy of 79.4% (specificity=83.6%, sensitivity=75.2%) based on speech pause related parameters extracted from recordings carried out in standard office (non-studio) environments. Acoustic and temporal analysis of speech may represent a potential tool for the objective analysis in schizophrenia.

  5. Acoustic and temporal analysis of speech: A potential biomarker for schizophrenia. (United States)

    Rapcan, Viliam; D'Arcy, Shona; Yeap, Sherlyn; Afzal, Natasha; Thakore, Jogin; Reilly, Richard B


    Currently, there are no established objective biomarkers for the diagnosis or monitoring of schizophrenia. It has been previously reported that there are notable qualitative differences in the speech of schizophrenics. The objective of this study was to determine whether a quantitative acoustic and temporal analysis of speech may be a potential biomarker for schizophrenia. In this study, 39 schizophrenic patients and 18 controls were digitally recorded reading aloud an emotionally neutral text passage from a children's story. Temporal, energy and vocal pitch features were automatically extracted from the recordings. A classifier based on linear discriminant analysis was employed to differentiate between controls and schizophrenic subjects. Processing the recordings with the algorithm developed demonstrated that it is possible to differentiate schizophrenic patients and controls with a classification accuracy of 79.4% (specificity=83.6%, sensitivity=75.2%) based on speech pause related parameters extracted from recordings carried out in standard office (non-studio) environments. Acoustic and temporal analysis of speech may represent a potential tool for the objective analysis in schizophrenia. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  6. 30th International Acoustical Imaging Symposium

    CERN Document Server

    Jones, Joie; Lee, Hua


    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 every two years 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 2009 the 30th International Symposium on Acoustical Imaging was held in Monterey, CA, USA, March 1-4. 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 30 in the Series contains an excellent collection of forty three papers presented in five major categories: Biomedical Imaging Acoustic Microscopy Non-Destructive Evaluation Systems Analysis Signal Analysis and Image Processing Audience Researchers in medical imaging and biomedical instrumentation experts.

  7. Guidelines for numerical vibration and acoustic analysis of disc brake squeal using simple models of brake systems (United States)

    Oberst, S.; Lai, J. C. S.; Marburg, S.


    Brake squeal has become of increasing concern to the automotive industry but guidelines on how to confidently predict squeal propensity are yet to be established. While it is standard practice to use the complex eigenvalue analysis to predict unstable vibration modes, there have been few attempts to calculate their acoustic radiation. Here guidelines are developed for numerical vibration and acoustic analysis of brake squeal using models of simplified brake systems with friction contact by considering (1) the selection of appropriate elements, contact and mesh; (2) the extraction of surface velocities via forced response; and (3) the calculation of the acoustic response itself. Results indicate that quadratic tetrahedral elements offer the best option for meshing more realistic geometry. A mesh has to be sufficiently fine especially in the contact region to predict mesh-independent unstable vibration modes. Regarding the vibration response, only the direct, steady-state method with a pressurised pad and finite sliding formulation (allowing contact separation) should be used. Comparison of different numerical methods suggest that a obroadband fast multi-pole boundary element method with the Burton-Miller formulation would efficiently solve the acoustic radiation of a full brake system. Results also suggest that a pad lift-off can amplify the acoustic radiation similar to a horn effect. A horn effect is also observed for chamfered pads which are used in practice to reduce the number and strength of unstable vibration modes. These results highlight the importance of optimising the pad shape to reduce acoustic radiation of unstable vibration modes.

  8. Seismo-acoustic analysis for series of ammunition demolition explosions at Sayarim, Israel (United States)

    Pinsky, V.; Gitterman, Y.; Ben-Horin, Y.; Arrowsmith, S.


    We analyzed detection and location capabilities of a seismo-acoustic network using records of explosion series conducted recently at Sayarim Military Range (SMR), Israel, for demolition of outdated ammunitions. The signals from the explosions have been recorded at local distances by the Israel Seismic Network (ISN), two single infrasound sensors co-located with ISN seismic stations and two infrasound arrays deployed by Israel NDC: 5-element IMA (at Mt. Meron), co-located with IMS seismic array MMAI, and 4-element test temporary array in Northern Negev. All shots (each one with nominal explosives weight ~10-15 tons, detonated simultaneously) were located at the same small area ~0.5x0.5 km, in some cases placed in several grooves, separated by 0.3-0.5 km. Some shots were divided in time by only 20-40 sec, facilitating analysis of the source variability under about constant atmospheric conditions. The following preliminary results have been obtained: 1) the accuracy of seismo-acoustic source location, provided by 5 seismic stations and 2 acoustic receivers using celerity model and wind profile for the day, was within ±1 km of the SMR explosion site; 2) the analysis of acoustic phases recorded at ISN seismic stations at different azimuths showed a clear correlation of the phase peak amplitude with the wind direction; 3) infrasound signals from the explosions were clearly detected at IMA array at 340 km, whereas seismic signals were attenuated below the background noise after 100-150 km; 4) the frequency band occupied by the signal is estimated within 0.2-5 Hz, and the f-k analysis, applied to the infrasound array recordings, provided azimuth of 184° and apparent velocity of 344 m/s, compared to the true azimuth 190° and celerity 277 m/s (the azimuth bias could be explained by the prevailing strong south-western winds ~80 knots observed at a time of the explosion at assumed propagation heights); 5) spectral analysis of infrasound signals provided determination of the

  9. Modeling of bulk acoustic wave devices built on piezoelectric stack structures: impedance matrix analysis and network representation. (United States)

    Zhang, Victor Y; Dubus, Bertrand; Lefebvre, Jean Etienne; Gryba, Tadeusz


    The fundamental electro-acoustic properties of a solid layer are deduced in terms of its impedance matrix (Z) and represented by a network for modeling the bulk acoustic wave devices built on piezoelectric stacked structures. A piezoelectric layer is described by a three-port equivalent network, a nonpiezoelectric layer, and a short- or open-circuit piezoelectric layer by a two-port one. Electrical input impedance of the resonator is derived in terms of the Z-matrix of both the piezoelectric layer and an external load, the unique expression applies whether the resonator is a mono- or electroded-layer or a solidly mounted resonator (SMR). The loading effects of Al-electrodes on the resonating frequencies of the piezoelectric ZnO-layer are analyzed. Transmission and reflection properties of Bragg mirrors are investigated along with the bulk radiation in SMR. As a synthesizing example, a coupled resonator filter (CRF) is analyzed using the associated two-port equivalent network and by calculating the power transmission to a 50Omega-load. The stacked crystal filter is naturally included in the model as a special case of CRF. Combining a comprehensive matrix analysis and an instructive network representation and setting the problem with a full vectorial formalism are peculiar features of the presented approach.

  10. Acoustic Force Density Acting on Inhomogeneous Fluids in Acoustic Fields

    DEFF Research Database (Denmark)

    Karlsen, Jonas Tobias; Augustsson, Per; Bruus, Henrik


    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...

  11. CFD Analysis of an Installation Used to Measure the Skin-Friction Penalty of Acoustic Treatments (United States)

    Spalart, Philippe R.; Garbaruk, Andrey; Howerton, Brian M.


    There is a drive to devise acoustic treatments with reduced skin-friction and therefore fuel-burn penalty for engine nacelles on commercial airplanes. The studies have been experimental, and the effects on skin-friction are deduced from measurements of the pressure drop along a duct. We conduct a detailed CFD analysis of the installation, for two purposes. The first is to predict the effects of the finite size of the rig, including its near-square cross-section and the moderate length of the treated patch; this introduces transient and blockage effects, which have not been included so far in the analysis. In addition, the flow is compressible, so that even with homogeneous surface conditions, it is not homogeneous in the streamwise direction. The second purpose is to extract an effective sand-grain roughness size for a particular liner, which in turn can be used in a CFD analysis of the aircraft, leading to actual predictions of the effect of acoustic treatments on fuel burn in service. The study is entirely based on classical turbulence models, with an appropriate modification for effective roughness effects, rather than directly modeling the liners.

  12. Analysis of failure mechanisms in fatigue test of reinforced concrete beam utilizing acoustic emission

    Directory of Open Access Journals (Sweden)

    N Bunnori


    Full Text Available The acoustic emission technique is used for monitoring the fatigue failure mechanisms in reinforced concrete beam under three point bending. The analysis was conducted by using the bathtub curve method plotted from acoustic emission data. In this study, the fatigue behavior was divided into three stages. The first stage is involved with the decreasing failure rate, known as early life failure or burn-in phase, the second stage is characterized by constant failure rate and the third stage is called the burn-out phase which is an increase of failure rate. The three parameters used in analyzing is the fatigue behavior for each stage of failure which are severity, signal strength and the cumulative signal strength. From severity analysis, the range of each stage of failure had been determined while from signal strength analysis, the initiation of distribution of crack had been detected through the fluctuation of signal strength. Cumulative signal strength parameter provides a clearer view of the initiation and distribution of crack.

  13. Nonlocal analysis of the excitation of the geodesic acoustic mode by drift waves

    DEFF Research Database (Denmark)

    Guzdar, P.N.; Kleva, R.G.; Chakrabarti, N.


    The geodesic acoustic modes (GAMs) are typically observed in the edge region of toroidal plasmas. Drift waves have been identified as a possible cause of excitation of GAMs by a resonant three wave parametric process. A nonlocal theory of excitation of these modes in inhomogeneous plasmas typical...... of the edge region of tokamaks is presented in this paper. The continuum GAM modes with coupling to the drift waves can create discrete "global" unstable eigenmodes localized in the edge "pedestal" region of the plasma. Multiple resonantly driven unstable radial eigenmodes can coexist on the edge pedestal....

  14. An acoustic assessment of Setswana vowels | le Roux | South ...

    African Journals Online (AJOL)

    This article probes into the acoustic analysis of the vowels of Setswana. The discussion is conducted against the background of the existing data presented in textbooks and other sources which are articulatory in nature and are based on auditive perceptions. An acoustic analysis is found to give much more reliable data ...

  15. Acoustic Environment of Haro Strait: Preliminary Propagation Modeling and Data Analysis

    National Research Council Canada - National Science Library

    Jones, Christopher D; Wolfson, Michael A


    Field measurements and acoustic propagation modeling for the frequency range 1 10 kHz are combined to analyze the acoustic environment of Haro Strait of Puget Sound, home to the southern resident killer whales...

  16. Energy based prediction models for building acoustics

    DEFF Research Database (Denmark)

    Brunskog, Jonas


    In order to reach robust and simplified yet accurate prediction models, energy based principle are commonly used in many fields of acoustics, especially in building acoustics. This includes simple energy flow models, the framework of statistical energy analysis (SEA) as well as more elaborated...... principles as, e.g., wave intensity analysis (WIA). The European standards for building acoustic predictions, the EN 12354 series, are based on energy flow and SEA principles. In the present paper, different energy based prediction models are discussed and critically reviewed. Special attention is placed...

  17. Preliminary study of acoustic analysis for evaluating speech-aid oral prostheses: Characteristic dips in octave spectrum for comparison of nasality


    Chang, Yen-Liang; Hung, Chao-Ho; CHEN, PO-YUEH; Chen, Wei-chang; Hung, Shih-Han


    Acoustic analysis is often used in speech evaluation but seldom for the evaluation of oral prostheses designed for reconstruction of surgical defect. This study aimed to introduce the application of acoustic analysis for patients with velopharyngeal insufficiency (VPI) due to oral surgery and rehabilitated with oral speech-aid prostheses. Methods: The pre- and postprosthetic rehabilitation acoustic features of sustained vowel sounds from two patients with VPI were analyzed and compared wit...

  18. a Psycholinguistic Model for Simultaneous Translation, and Proficiency Assessment by Automated Acoustic Analysis of Discourse. (United States)

    Yaghi, Hussein M.

    Two separate but related issues are addressed: how simultaneous translation (ST) works on a cognitive level and how such translation can be objectively assessed. Both of these issues are discussed in the light of qualitative and quantitative analyses of a large corpus of recordings of ST and shadowing. The proposed ST model utilises knowledge derived from a discourse analysis of the data, many accepted facts in the psychology tradition, and evidence from controlled experiments that are carried out here. This model has three advantages: (i) it is based on analyses of extended spontaneous speech rather than word-, syllable-, or clause -bound stimuli; (ii) it draws equally on linguistic and psychological knowledge; and (iii) it adopts a non-traditional view of language called 'the linguistic construction of reality'. The discourse-based knowledge is also used to develop three computerised systems for the assessment of simultaneous translation: one is a semi-automated system that treats the content of the translation; and two are fully automated, one of which is based on the time structure of the acoustic signals whilst the other is based on their cross-correlation. For each system, several parameters of performance are identified, and they are correlated with assessments rendered by the traditional, subjective, qualitative method. Using signal processing techniques, the acoustic analysis of discourse leads to the conclusion that quality in simultaneous translation can be assessed quantitatively with varying degrees of automation. It identifies as measures of performance (i) three content-based standards; (ii) four time management parameters that reflect the influence of the source on the target language time structure; and (iii) two types of acoustical signal coherence. Proficiency in ST is shown to be directly related to coherence and speech rate but inversely related to omission and delay. High proficiency is associated with a high degree of simultaneity and

  19. Modification of computational auditory scene analysis (CASA) for noise-robust acoustic feature (United States)

    Kwon, Minseok

    While there have been many attempts to mitigate interferences of background noise, the performance of automatic speech recognition (ASR) still can be deteriorated by various factors with ease. However, normal hearing listeners can accurately perceive sounds of their interests, which is believed to be a result of Auditory Scene Analysis (ASA). As a first attempt, the simulation of the human auditory processing, called computational auditory scene analysis (CASA), was fulfilled through physiological and psychological investigations of ASA. CASA comprised of Zilany-Bruce auditory model, followed by tracking fundamental frequency for voice segmentation and detecting pairs of onset/offset at each characteristic frequency (CF) for unvoiced segmentation. The resulting Time-Frequency (T-F) representation of acoustic stimulation was converted into acoustic feature, gammachirp-tone frequency cepstral coefficients (GFCC). 11 keywords with various environmental conditions are used and the robustness of GFCC was evaluated by spectral distance (SD) and dynamic time warping distance (DTW). In "clean" and "noisy" conditions, the application of CASA generally improved noise robustness of the acoustic feature compared to a conventional method with or without noise suppression using MMSE estimator. The intial study, however, not only showed the noise-type dependency at low SNR, but also called the evaluation methods in question. Some modifications were made to capture better spectral continuity from an acoustic feature matrix, to obtain faster processing speed, and to describe the human auditory system more precisely. The proposed framework includes: 1) multi-scale integration to capture more accurate continuity in feature extraction, 2) contrast enhancement (CE) of each CF by competition with neighboring frequency bands, and 3) auditory model modifications. The model modifications contain the introduction of higher Q factor, middle ear filter more analogous to human auditory system

  20. Design and analysis of the trapeziform and flat acoustic cloaks with controllable invisibility performance in a quasi-space

    Directory of Open Access Journals (Sweden)

    Jian Zhu


    Full Text Available We present the design, implementation and detailed performance analysis for a class of trapeziform and flat acoustic cloaks. An effective large invisible area is obtained compared with the traditional carpet cloak. The cloaks are realized with homogeneous metamaterials which are made of periodic arrangements of subwavelength unit cells composed of steel embedded in air. The microstructures and its effective parameters of the cloaks are determined quickly and precisely in a broadband frequency range by using the effective medium theory and the proposed parameters optimization method. The invisibility capability of the cloaks can be controlled by the variation of the key design parameters and scale factor which are proved to have more influence on the performance in the near field than that in the far field. Different designs are suitable for different application situations. Good cloaking performance demonstrates that such a device can be physically realized with natural materials which will greatly promote the real applications of invisibility cloak.

  1. Student design projects in applied acoustics. (United States)

    Bös, Joachim; Moritz, Karsten; Skowronek, Adam; Thyes, Christian; Tschesche, Johannes; Hanselka, Holger


    This paper describes a series of student projects which are intended to complement theoretical education in acoustics and engineering noise control with practical experience. The projects are also intended to enhance the students' ability to work in a team, to manage a project, and to present their results. The projects are carried out in close cooperation with industrial partners so that the students can get a taste of the professional life of noise control engineers. The organization of such a project, its execution, and some of the results from the most recent student project are presented as a demonstrative example. This latest project involved the creation of noise maps of a production hall, the acoustic analysis of a packaging machine, and the acoustic analysis of a spiral vibratory conveyor. Upon completion of the analysis, students then designed, applied, and verified some simple preliminary noise reduction measures to demonstrate the potential of these techniques. © 2012 Acoustical Society of America

  2. No Acoustic Evidence from RHD for a Right Hemisphere Role in Prosody Production: A Meta-Analysis

    DEFF Research Database (Denmark)

    Weed, Ethan; Fusaroli, Riccardo

    No acoustic evidence from RHD for a right hemisphere role in prosody production: A meta-analysis. Ethan Weed and Riccardo Fusaroli (Aarhus University, Denmark) Poster : The right hemisphere (RH) is often thought to have a special role in prosody comprehension and production in general......, and affective prosody in particular. If RH structures support prosody wholly or in part, we would expect acoustic differences between the productions of people with right hemisphere damage (RHD) and non brain-damaged (NBD) controls. Such differences have been reported, but the literature is mixed, and spans...... many years and experimental design types. To get perspective on the scope of these results, we conducted a systematic review and meta-analysis of acoustic measures of prosody production in people with RHD. We searched PubMed, PsychINFO, Web of Science and Google Scholar with the terms: (prosody...

  3. Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Direct field formulations (United States)

    Alimonti, L.; Atalla, N.


    This paper is concerned with the development of a simplified model for noise control treatments to speed up finite element analysis in vibroacoustic applications. The methodology relies on the assumption that the acoustic treatment is flat and homogeneous. Moreover, its finite lateral extent is neglected. This hypothesis is justified by short wavelength and large dissipation, which suggest that the reflected field emanating from the acoustic treatment lateral boundaries does not substantially affect its dynamic response. Under these circumstances, the response of the noise control treatment can be formally obtained by means of convolution integrals involving simple analytical kernels (i.e. Green functions). Such fundamental solutions can be computed efficiently by the transfer matrix method. However, some arbitrariness arises in the formulation of the mathematical model, resulting in different baffling conditions at the two ends of the treatment to be considered. Thus, the paper investigates the possibility of different formulations (i.e. baffling conditions) within the same hybrid finite element-transfer matrix framework, seeking for the best strategy in terms of tradeoff between efficiency and accuracy. Numerical examples are provided to show strengths and limitations of the proposed methodology.

  4. Stress-Induced Fracturing of Reservoir Rocks: Acoustic Monitoring and μCT Image Analysis (United States)

    Pradhan, Srutarshi; Stroisz, Anna M.; Fjær, Erling; Stenebråten, Jørn F.; Lund, Hans K.; Sønstebø, Eyvind F.


    Stress-induced fracturing in reservoir rocks is an important issue for the petroleum industry. While productivity can be enhanced by a controlled fracturing operation, it can trigger borehole instability problems by reactivating existing fractures/faults in a reservoir. However, safe fracturing can improve the quality of operations during CO2 storage, geothermal installation and gas production at and from the reservoir rocks. Therefore, understanding the fracturing behavior of different types of reservoir rocks is a basic need for planning field operations toward these activities. In our study, stress-induced fracturing of rock samples has been monitored by acoustic emission (AE) and post-experiment computer tomography (CT) scans. We have used hollow cylinder cores of sandstones and chalks, which are representatives of reservoir rocks. The fracture-triggering stress has been measured for different rocks and compared with theoretical estimates. The population of AE events shows the location of main fracture arms which is in a good agreement with post-test CT image analysis, and the fracture patterns inside the samples are visualized through 3D image reconstructions. The amplitudes and energies of acoustic events clearly indicate initiation and propagation of the main fractures. Time evolution of the radial strain measured in the fracturing tests will later be compared to model predictions of fracture size.

  5. Experimental analysis of crack evolution in concrete by the acoustic emission technique

    Directory of Open Access Journals (Sweden)

    J. Saliba


    Full Text Available The fracture process zone (FPZ was investigated on unnotched and notched beams with different notch depths. Three point bending tests were realized on plain concrete under crack mouth opening displacement (CMOD control. Crack growth was monitored by applying the acoustic emission (AE technique. In order to improve our understanding of the FPZ, the width and length of the FPZ were followed based on the AE source locations maps and several AE parameters were studied during the entire loading process. The bvalue analysis, defined as the log-linear slope of the frequency-magnitude distribution of acoustic emissions, was also carried out to describe quantitatively the influence of the relative notch depth on the fracture process. The results show that the number of AE hits increased with the decrease of the relative notch depth and an important AE energy dissipation was observed at the crack initiation in unnotched beams. In addition, the relative notch depth influenced the AE characteristics, the process of crack propagation, and the brittleness of concrete.

  6. Towards non-contact photo-acoustic endoscopy using speckle pattern analysis (United States)

    Lengenfelder, Benjamin; Mehari, Fanuel; Tang, Yuqi; Klämpfl, Florian; Zalevsky, Zeev; Schmidt, Michael


    Photoacoustic Tomography combines the advantages of optical and acoustic imaging as it makes use of the high optical contrast of tissue and the high resolution of ultrasound. Furthermore, high penetration depths in tissue in the order of several centimeters can be achieved by the combination of these modalities. Extensive research is being done in the field of miniaturization of photoacoustic devices, as photoacoustic imaging could be of significant benefits for the physician during endoscopic interventions. All the existing miniature systems are based on contact transducers for signal detection that are placed at the distal end of an endoscopic device. This makes the manufacturing process difficult and impedance matching to the inspected surface a requirement. The requirement for contact limits the view of the physician during the intervention. Consequently, a fiber based non-contact optical sensing technique would be highly beneficial for the development of miniaturized photoacoustic endoscopic devices. This work demonstrates the feasibility of surface displacement detection using remote speckle-sensing using a high speed camera and an imaging fiber bundle that is used in commercially available video endoscopes. The feasibility of displacement sensing is demonstrated by analysis of phantom vibrations which are induced by loudspeaker membrane oscillations. Since the usability of the remote speckle-sensing for photo-acoustic signal detection was already demonstrated, the fiber bundle approach demonstrates the potential for non-contact photoacoustic detections during endoscopy.

  7. Auto-identification of engine fault acoustic signal through inverse trigonometric instantaneous frequency analysis

    Directory of Open Access Journals (Sweden)

    Dayong Ning


    Full Text Available The acoustic signals of internal combustion engines contain valuable information about the condition of engines. These signals can be used to detect incipient faults in engines. However, these signals are complex and composed of a faulty component and other noise signals of background. As such, engine conditions’ characteristics are difficult to extract through wavelet transformation and acoustic emission techniques. In this study, an instantaneous frequency analysis method was proposed. A new time–frequency model was constructed using a fixed amplitude and a variable cycle sine function to fit adjacent points gradually from a time domain signal. The instantaneous frequency corresponds to single value at any time. This study also introduced instantaneous frequency calculation on the basis of an inverse trigonometric fitting method at any time. The mean value of all local maximum values was then considered to identify the engine condition automatically. Results revealed that the mean of local maximum values under faulty conditions differs from the normal mean. An experiment case was also conducted to illustrate the availability of the proposed method. Using the proposed time–frequency model, we can identify engine condition and determine abnormal sound produced by faulty engines.

  8. Analysis and presentation. Clinical trials on prostate cancer. (United States)

    Friberg, S; Taube, A; Sylvester, R; Oesterling, J E


    To present guidelines for the analysis and presentation of clinical trials on prostate cancer. Textbooks in statistics and oncology were searched for information, as were separate articles on the topic. Previously published advice was fused with own experience. Minimum key points are given for the sections: Introduction, Materials and Methods, Results, Discussion, and Summary. The importance of 1 primary question in any clinical trial is stressed. The value of a detailed presentation of the trial design, the patient population and the inclusion/exclusion criteria, the characterization of the disease, the treatment schedules, and toxicity is underlined. Application of various statistical methods for different endpoints is suggested. Maturity of data, time for publication, and avoidance of publication bias are discussed. Some common pitfalls in the statistical analyses of clinical results are indicated. The impact of prognostic factors, proper staging procedures, and secondary treatments on the interpretation of survival analysis is pointed out. A shift from the (mis-)use of the P value in favor of confidence intervals is strongly encouraged. The use of comparing the survival of responders versus nonresponders is to be abandoned. A few practical hints concerning the presentation are offered. The minimum of data that should be presented in absolute numbers is indicated. Also, the data that should be provided in both graphic and numeric format are exemplified. Examples of essential graphic illustrations are provided. The need for improvements in the design analysis, and presentation of clinical trials is reemphasized. Finally, numerous references are listed. The article is addressed not only to authors and readers of clinical trials, but also to editors of medical journals. The suggested guidelines may be useful in the analysis, presentation, and interpretation of clinical trials on prostate cancer. Moreover, compliance with these guidelines may facilitate comparisons

  9. High school students presenting science: An interactional sociolinguistic analysis (United States)

    Bleicher, Robert

    Presenting science is an authentic activity of practicing scientists. Thus, effective communication of science is an important skill to nurture in high school students who are learning science. This study examines strategies employed by high school students as they make science presentations; it assesses students' conceptual understandings of particular science topics through their presentations and investigates gender differences. Data are derived from science presentation given by eight high school students, three females and five males who attended a summer science program. Data sources included videotaped presentations, ethnographic fieldnotes, interviews with presenters and members of the audience, and presenter notes and overheads. Presentations were transcribed and submitted to discourse analysis from an interactional sociolinguistic perspective. This article focuses on the methodology employed and how it helps inform the above research questions. The author argues that use of this methodology leads to findings that inform important social-communicative issues in the learning of science. Practical advice for teaching students to present science, implications for use of presentations to assess conceptual learning, and indications of some possible gender differences are discussed.Received: 14 April 1993; Revised: 15 February 1994;

  10. [Processing acoustically presented time intervals of seconds duration: an expression of the phonological loop of the working memory?]. (United States)

    Grube, D


    Working memory has been proposed to contribute to the processing of time, rhythm and music; the question which component of working memory is involved is under discussion. The present study tests the hypothesis that the phonological loop component (Baddeley, 1986) is involved in the processing of auditorily presented time intervals of a few seconds' duration. Typical effects well known with short-term retention of verbal material could be replicated with short-term retention of temporal intervals: The immediate reproduction of time intervals was impaired under conditions of background music and articulatory suppression. Neither the accuracy nor the speed of responses in a (non-phonological) mental rotation task were diminished under these conditions. Processing of auditorily presented time intervals seems to be constrained by the capacity of the phonological loop: The immediate serial recall of sequences of time intervals was shown to be related to the immediate serial recall of words (memory span). The results confirm the notion that working memory resources, and especially the phonological loop component, underlie the processing of auditorily presented temporal information with a duration of a few seconds.

  11. Monitoring and Failure Analysis of Corroded Bridge Cables under Fatigue Loading Using Acoustic Emission Sensors

    Directory of Open Access Journals (Sweden)

    Hui Li


    Full Text Available Cables play an important role in cable-stayed systems, but are vulnerable to corrosion and fatigue damage. There is a dearth of studies on the fatigue damage evolution of corroded cable. In the present study, the acoustic emission (AE technology is adopted to monitor the fatigue damage evolution process. First, the relationship between stress and strain is determined through a tensile test for corroded and non-corroded steel wires. Results show that the mechanical performance of corroded cables is changed considerably. The AE characteristic parameters for fatigue damage are then established. AE energy cumulative parameters can accurately describe the fatigue damage evolution of corroded cables. The failure modes in each phase as well as the type of acoustic emission source are determined based on the results of scanning electron microscopy. The waveform characteristics, damage types, and frequency distribution of the corroded cable at different damage phases are collected. Finally, the number of broken wires and breakage time of the cables are determined according to the variation in the margin index.

  12. Monitoring and Failure Analysis of Corroded Bridge Cables under Fatigue Loading Using Acoustic Emission Sensors (United States)

    Li, Dongsheng; Ou, Jinping; Lan, Chengming; Li, Hui


    Cables play an important role in cable-stayed systems, but are vulnerable to corrosion and fatigue damage. There is a dearth of studies on the fatigue damage evolution of corroded cable. In the present study, the acoustic emission (AE) technology is adopted to monitor the fatigue damage evolution process. First, the relationship between stress and strain is determined through a tensile test for corroded and non-corroded steel wires. Results show that the mechanical performance of corroded cables is changed considerably. The AE characteristic parameters for fatigue damage are then established. AE energy cumulative parameters can accurately describe the fatigue damage evolution of corroded cables. The failure modes in each phase as well as the type of acoustic emission source are determined based on the results of scanning electron microscopy. The waveform characteristics, damage types, and frequency distribution of the corroded cable at different damage phases are collected. Finally, the number of broken wires and breakage time of the cables are determined according to the variation in the margin index. PMID:22666009

  13. Design and analysis of air acoustic vector-sensor configurations for two-dimensional geometry. (United States)

    Wajid, Mohd; Kumar, Arun; Bahl, Rajendar


    Acoustic vector-sensors (AVS) have been designed using the P-P method for different microphone configurations. These configurations have been used to project the acoustic intensity on the orthogonal axes through which the direction of arrival (DoA) of a sound source has been estimated. The analytical expressions for the DoA for different microphone configurations have been derived for two-dimensional geometry. Finite element method simulation using COMSOL-Multiphysics has been performed, where the microphone signals for AVS configurations have been recorded in free field conditions. The performance of all the configurations has been evaluated with respect to angular error and root-mean-square angular error. The simulation results obtained with ideal geometry for different configurations have been corroborated experimentally with prototype AVS realizations and also compared with microphone-array method, viz., Multiple Signal Classification and Generalized Cross Correlation. Experiments have been performed in an anechoic room using different prototype AVS configurations made from small size microphones. The DoA performance using analytical expressions, simulation studies, and experiments with prototype AVS in anechoic chamber are presented in the paper. The square and delta configurations are found to perform better in the absence and presence of noise, respectively.

  14. Bifurcation analysis for ion acoustic waves in a strongly coupled plasma including trapped electrons (United States)

    El-Labany, S. K.; El-Taibany, W. F.; Atteya, A.


    The nonlinear ion acoustic wave propagation in a strongly coupled plasma composed of ions and trapped electrons has been investigated. The reductive perturbation method is employed to derive a modified Korteweg-de Vries-Burgers (mKdV-Burgers) equation. To solve this equation in case of dissipative system, the tangent hyperbolic method is used, and a shock wave solution is obtained. Numerical investigations show that, the ion acoustic waves are significantly modified by the effect of polarization force, the trapped electrons and the viscosity coefficients. Applying the bifurcation theory to the dynamical system of the derived mKdV-Burgers equation, the phase portraits of the traveling wave solutions of both of dissipative and non-dissipative systems are analyzed. The present results could be helpful for a better understanding of the waves nonlinear propagation in a strongly coupled plasma, which can be produced by photoionizing laser-cooled and trapped electrons [1], and also in neutron stars or white dwarfs interior.

  15. Acoustic chaos

    Energy Technology Data Exchange (ETDEWEB)

    Lauterborn, W.; Parlitz, U. [Drittes Physikalisches Institut, Universitaet Goettingen, D-37073 Goettingen (Germany); Holzfuss, J.; Billo, A. [Institut fuer Angewandte Physik, Technische Hochschule Darmstadt, D-64289 Darmstadt (Germany); Akhatov, I. [Department of Continuous Media Mechanics, Bashkir State University, Ufa 450074 (Russia)


    Acoustic cavitation, a complex, spatio-temporal dynamical system, is investigated with respect to its chaotic properties. The sound output, the {open_quote}{open_quote}noise{close_quote}{close_quote}, is subjected to time series analysis. The spatial dynamics of the bubble filaments is captured by high speed holographic cinematography and subsequent digital picture processing from the holograms. Theoretical models are put forward for describing the pattern formation. {copyright} {ital 1996 American Institute of Physics.}

  16. Acoustic multivariate condition monitoring - AMCM

    Energy Technology Data Exchange (ETDEWEB)

    Rosenhave, P.E. [Vestfold College, Maritime Dept., Toensberg (Norway)


    In Norway, Vestfold College, Maritime Department presents new opportunities for non-invasive, on- or off-line acoustic monitoring of rotating machinery such as off-shore pumps and diesel engines. New developments within acoustic sensor technology coupled with chemometric data analysis of complex signals now allow condition monitoring of hitherto unavailable flexibility and diagnostic specificity. Chemometrics paired with existing knowledge yields a new and powerful tool for condition monitoring. By the use of multivariate techniques and acoustics it is possible to quantify wear and tear as well as predict the performance of working components in complex machinery. This presentation describes the AMCM method and one result of a feasibility study conducted onboard the LPG/C `Norgas Mariner` owned by Norwegian Gas Carriers as (NGC), Oslo. (orig.) 6 refs.

  17. Architectural acoustics

    National Research Council Canada - National Science Library

    Long, Marshall


    .... 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...

  18. Nonlinear Acoustic Response of an Aircraft Fuselage Sidewall Structure by a Reduced-Order Analysis (United States)

    Przekop, Adam; Rizzi, Stephen A.; Groen, David S.


    A reduced-order nonlinear analysis of a structurally complex aircraft fuselage sidewall panel is undertaken to explore issues associated with application of such analyses to practical structures. Of primary interest is the trade-off between computational efficiency and accuracy. An approach to modal basis selection is offered based upon the modal participation in the linear regime. The nonlinear static response to a uniform pressure loading and nonlinear random response to a uniformly distributed acoustic loading are computed. Comparisons of the static response with a nonlinear static solution in physical degrees-of-freedom demonstrate the efficacy of the approach taken for modal basis selection. Changes in the modal participation as a function of static and random loading levels suggest a means for improvement in the basis selection.

  19. Comparison of sonochemiluminescence images using image analysis techniques and identification of acoustic pressure fields via simulation. (United States)

    Tiong, T Joyce; Chandesa, Tissa; Yap, Yeow Hong


    One common method to determine the existence of cavitational activity in power ultrasonics systems is by capturing images of sonoluminescence (SL) or sonochemiluminescence (SCL) in a dark environment. Conventionally, the light emitted from SL or SCL was detected based on the number of photons. Though this method is effective, it could not identify the sonochemical zones of an ultrasonic systems. SL/SCL images, on the other hand, enable identification of 'active' sonochemical zones. However, these images often provide just qualitative data as the harvesting of light intensity data from the images is tedious and require high resolution images. In this work, we propose a new image analysis technique using pseudo-colouring images to quantify the SCL zones based on the intensities of the SCL images and followed by comparison of the active SCL zones with COMSOL simulated acoustic pressure zones. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. The acoustic sensor for rapid analysis of bacterial cells in the conductive suspensions. (United States)

    Borodina, I A; Zaitsev, B D; Guliy, O; Teplykh, A A; Shikhabudinov, A M


    The possibility of using the acoustic sensor on the basis of a two-channel delay line for rapid analysis of bacterial cells in the conductive suspensions was investigated. The dependencies of change in phase and insertion loss of output signal of the sensor on conductivity of buffer solution with various concentrations of cells due to a specific interaction "bacterial cells - mini-antibodies" for electrically open and electrically shorted channels of delay line were measured. It has been found that these changes have the most values for the electrically open channel. It has been also shown that the sensor rapidly responds to the specific interaction and the time stabilization of the phase and insertion loss of output signal is less than 10min. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Characteristic analysis of underwater acoustic scattering echoes in the wavelet transform domain (United States)

    Yang, Mei; Li, Xiukun; Yang, Yang; Meng, Xiangxia


    Underwater acoustic scattering echoes have time-space structures and are aliasing in time and frequency domains. Different series of echoes properties are not identified when incident angle is unknown. This article investigates variations in target echoes of monostatic sonar to address this problem. The mother wavelet with similar structures has been proposed on the basis of preprocessing signal waveform using matched filter, and the theoretical expressions between delay factor and incident angle are derived in the wavelet domain. Analysis of simulation data and experimental results in free-field pool show that this method can effectively separate geometrical scattering components of target echoes. The time delay estimation obtained from geometrical echoes at a single angle is consistent with target geometrical features, which provides a basis for object recognition without angle information. The findings provide valuable insights for analyzing elastic scattering echoes in actual ocean environment.

  2. Acoustic emission for interlaminar toughness testing of CFRP: Evaluation of the crack growth due to burst analysis

    Czech Academy of Sciences Publication Activity Database

    Lissek, F.; Haegerb, A.; Knoblauch, V.; Hloch, Sergej; Pude, F.; Kaufeld, M.


    Roč. 136, č. 1 (2018), s. 55-62 ISSN 1359-8368 Institutional support: RVO:68145535 Keywords : DCB * interlaminar toughness testing * acoustic emission * CFRP * burst analysis Subject RIV: JQ - Machines ; Tools Impact factor: 4.727, year: 2016

  3. No Acoustic Evidence from RHD for a Right Hemisphere Role in Prosody Production: A Meta-Analysis

    DEFF Research Database (Denmark)

    Weed, Ethan; Fusaroli, Riccardo

    many years and experimental design types. To get perspective on the scope of these results, we conducted a systematic review and meta-analysis of acoustic measures of prosody production in people with RHD. We searched PubMed, PsychINFO, Web of Science and Google Scholar with the terms: (prosody...

  4. Systems analysis of past, present, and future chemical terrorism scenarios.

    Energy Technology Data Exchange (ETDEWEB)

    Hoette, Trisha Marie


    Throughout history, as new chemical threats arose, strategies for the defense against chemical attacks have also evolved. As a part of an Early Career Laboratory Directed Research and Development project, a systems analysis of past, present, and future chemical terrorism scenarios was performed to understand how the chemical threats and attack strategies change over time. For the analysis, the difficulty in executing chemical attack was evaluated within a framework of three major scenario elements. First, historical examples of chemical terrorism were examined to determine how the use of chemical threats, versus other weapons, contributed to the successful execution of the attack. Using the same framework, the future of chemical terrorism was assessed with respect to the impact of globalization and new technologies. Finally, the efficacy of the current defenses against contemporary chemical terrorism was considered briefly. The results of this analysis justify the need for continued diligence in chemical defense.

  5. Acoustic Territoriality

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob


    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....

  6. [Comparative analysis of neuroendoscope-assisted microsurgery and microscope treatment for small acoustic neuroma]. (United States)

    Yao, Xiaohui; Ji, Hongming; Zhang, Shiyuan; Ding, Xinmin; Zhang, Gangli; Zhang, Yan


    To explore the outcomes of surgery for the treatment of small acoustic neuroma by the neuroendoscope-assisted microsurgery and microscope. From 2008 to 2013, 42 patients with small acoustic neuroma underwent neuroendoscope-assisted microsurgery (n = 20) and microscopic tumoural resection (n = 22). Neurophysiological monitoring, 30-degree rigid neuroendoscope and microscope were employed intra-operatively. For the endoscope group, facial nerve and inner acoustic meatus could be visualized distinctly in each aspect, as for the microscope group, microscopic operation could be accomplished directly. The damage extents of facial nerve and inner acoustic meatus were compared between two groups. Total removal of acoustic neuroma and conservation of facial nerve were achieved in all patients. For the neuroendoscope-assisted group, the postoperative facial functions were Grade I (n = 6), Grade II (n = 10) and Grade III (n = 4). Internal acoustic canal was drilled 2-3 mm in 4 patients and no drilling in others. For the microscope group, Grade I (n = 5), Grade II (n = 6), Grade III (n = 8) and Grade III-IV (n = 3). Internal acoustic canal was drilled at least 3 mm in 12 patients and no drilling in others. No complication such as cerebrospinal fluid leakage occurred during the follow-ups. Endosocopic operation of acoustic neuroma surgery is superior to microscopic operation in terms of magnification, illumination, wide-angel and angulation. And the former procedure may yield better outcomes through alleviating the damage of facial nerve and decreasing the drilling degree of inner acoustic meatus.

  7. Analysis of Gender Equality Competence Present in Cultural Positions

    Directory of Open Access Journals (Sweden)

    Concepción Mimbrero Mallado

    Full Text Available Abstract: Articulating the gender dimension in organizations is not easy because their members have to be trained to adopt positions that facilitate the implementation of solutions that help to combat inequalities. The aim of this article was to identify the gender equality competence present in the three types of cultural positions Castells proposed in members of a City CouncilinSevilla-Spain, who wanted to implement gender mainstreaming. The participants were 27 people (16 women and 11 men. The methodused was discourse analysis. The obtained results show that, while all competences were present in the projectposition,in the resistance position, there was none. In the legitimizers, we observed inconsistency in the discourse presented. This arouses considerations on the importance of knowing the gender equality competences in order to implement gender mainstreaming in organizations.

  8. Deep Water Ocean Acoustics (United States)


    for including this in acoustic models . Experimental analysis is combined with model development to isolate specific physics and improve our...under- ice scattering, bathymetric diffraction and the application of the ocean acoustic Parabolic Equation to infrasound. 2. Tasks a. Task 1: Basin...of Japan received at the CTBTO HA03 station in Juan Fernandez Chile , are a treasure trove of long-range low frequency acoustic propagation. In

  9. Modeling and Analysis of Lateral Propagation of Surface Acoustic Waves Including Coupling Between Different Waves. (United States)

    Zhang, Benfeng; Han, Tao; Tang, Gongbin; Zhang, Qiaozhen; Omori, Tatsuya; Hashimoto, Ken-Ya


    This paper discusses lateral propagation of surface acoustic waves (SAWs) in periodic grating structures when two types of SAWs exist simultaneously and are coupled. The thin plate model proposed by the authors is extended to include the coupling between two different SAW modes. First, lateral SAW propagation in an infinitely long periodic grating is modeled and discussed. Then, the model is applied to the Al-grating/42° YX-LiTaO3 (42-LT) substrate structure, and it is shown that the slowness curve shape changes from concave to convex with the Al grating thickness. The transverse responses are also analyzed on an infinitely long interdigital transducer on the structure, and good agreement is achieved between the present and the finite-element method analyses. Finally, SAW resonators are fabricated on the Cu grating/42-LT substrate structure, and it is experimentally verified that the slowness curve shape of the shear horizontal SAW changes with the Cu thickness.

  10. Advanced Active Acoustics Lab (AAAL) (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...

  11. Cave acoustics in prehistory: Exploring the association of Palaeolithic visual motifs and acoustic response. (United States)

    Fazenda, Bruno; Scarre, Chris; Till, Rupert; Pasalodos, Raquel Jiménez; Guerra, Manuel Rojo; Tejedor, Cristina; Peredo, Roberto Ontañón; Watson, Aaron; Wyatt, Simon; Benito, Carlos García; Drinkall, Helen; Foulds, Frederick


    During the 1980 s, acoustic studies of Upper Palaeolithic imagery in French caves-using the technology then available-suggested a relationship between acoustic response and the location of visual motifs. This paper presents an investigation, using modern acoustic measurement techniques, into such relationships within the caves of La Garma, Las Chimeneas, La Pasiega, El Castillo, and Tito Bustillo in Northern Spain. It addresses methodological issues concerning acoustic measurement at enclosed archaeological sites and outlines a general framework for extraction of acoustic features that may be used to support archaeological hypotheses. The analysis explores possible associations between the position of visual motifs (which may be up to 40 000 yrs old) and localized acoustic responses. Results suggest that motifs, in general, and lines and dots, in particular, are statistically more likely to be found in places where reverberation is moderate and where the low frequency acoustic response has evidence of resonant behavior. The work presented suggests that an association of the location of Palaeolithic motifs with acoustic features is a statistically weak but tenable hypothesis, and that an appreciation of sound could have influenced behavior among Palaeolithic societies of this region.

  12. A new acoustic portal into the odontocete ear and vibrational analysis of the tympanoperiotic complex.

    Directory of Open Access Journals (Sweden)

    Ted W Cranford

    Full Text Available Global concern over the possible deleterious effects of noise on marine organisms was catalyzed when toothed whales stranded and died in the presence of high intensity sound. The lack of knowledge about mechanisms of hearing in toothed whales prompted our group to study the anatomy and build a finite element model to simulate sound reception in odontocetes. The primary auditory pathway in toothed whales is an evolutionary novelty, compensating for the impedance mismatch experienced by whale ancestors as they moved from hearing in air to hearing in water. The mechanism by which high-frequency vibrations pass from the low density fats of the lower jaw into the dense bones of the auditory apparatus is a key to understanding odontocete hearing. Here we identify a new acoustic portal into the ear complex, the tympanoperiotic complex (TPC and a plausible mechanism by which sound is transduced into the bony components. We reveal the intact anatomic geometry using CT scanning, and test functional preconceptions using finite element modeling and vibrational analysis. We show that the mandibular fat bodies bifurcate posteriorly, attaching to the TPC in two distinct locations. The smaller branch is an inconspicuous, previously undescribed channel, a cone-shaped fat body that fits into a thin-walled bony funnel just anterior to the sigmoid process of the TPC. The TPC also contains regions of thin translucent bone that define zones of differential flexibility, enabling the TPC to bend in response to sound pressure, thus providing a mechanism for vibrations to pass through the ossicular chain. The techniques used to discover the new acoustic portal in toothed whales, provide a means to decipher auditory filtering, beam formation, impedance matching, and transduction. These tools can also be used to address concerns about the potential deleterious effects of high-intensity sound in a broad spectrum of marine organisms, from whales to fish.

  13. Analysis and Computation of Acoustic and Elastic Wave Equations in Random Media

    KAUST Repository

    Motamed, Mohammad


    We propose stochastic collocation methods for solving the second order acoustic and elastic wave equations in heterogeneous random media and subject to deterministic boundary and initial conditions [1, 4]. We assume that the medium consists of non-overlapping sub-domains with smooth interfaces. In each sub-domain, the materials coefficients are smooth and given or approximated by a finite number of random variable. One important example is wave propagation in multi-layered media with smooth interfaces. The numerical scheme consists of a finite difference or finite element method in the physical space and a collocation in the zeros of suitable tensor product orthogonal polynomials (Gauss points) in the probability space. We provide a rigorous convergence analysis and demonstrate different types of convergence of the probability error with respect to the number of collocation points under some regularity assumptions on the data. In particular, we show that, unlike in elliptic and parabolic problems [2, 3], the solution to hyperbolic problems is not in general analytic with respect to the random variables. Therefore, the rate of convergence is only algebraic. A fast spectral rate of convergence is still possible for some quantities of interest and for the wave solutions with particular types of data. We also show that the semi-discrete solution is analytic with respect to the random variables with the radius of analyticity proportional to the grid/mesh size h. We therefore obtain an exponential rate of convergence which deteriorates as the quantity h p gets smaller, with p representing the polynomial degree in the stochastic space. We have shown that analytical results and numerical examples are consistent and that the stochastic collocation method may be a valid alternative to the more traditional Monte Carlo method. Here we focus on the stochastic acoustic wave equation. Similar results are obtained for stochastic elastic equations.

  14. A New Acoustic Portal into the Odontocete Ear and Vibrational Analysis of the Tympanoperiotic Complex (United States)

    Cranford, Ted W.; Krysl, Petr; Amundin, Mats


    Global concern over the possible deleterious effects of noise on marine organisms was catalyzed when toothed whales stranded and died in the presence of high intensity sound. The lack of knowledge about mechanisms of hearing in toothed whales prompted our group to study the anatomy and build a finite element model to simulate sound reception in odontocetes. The primary auditory pathway in toothed whales is an evolutionary novelty, compensating for the impedance mismatch experienced by whale ancestors as they moved from hearing in air to hearing in water. The mechanism by which high-frequency vibrations pass from the low density fats of the lower jaw into the dense bones of the auditory apparatus is a key to understanding odontocete hearing. Here we identify a new acoustic portal into the ear complex, the tympanoperiotic complex (TPC) and a plausible mechanism by which sound is transduced into the bony components. We reveal the intact anatomic geometry using CT scanning, and test functional preconceptions using finite element modeling and vibrational analysis. We show that the mandibular fat bodies bifurcate posteriorly, attaching to the TPC in two distinct locations. The smaller branch is an inconspicuous, previously undescribed channel, a cone-shaped fat body that fits into a thin-walled bony funnel just anterior to the sigmoid process of the TPC. The TPC also contains regions of thin translucent bone that define zones of differential flexibility, enabling the TPC to bend in response to sound pressure, thus providing a mechanism for vibrations to pass through the ossicular chain. The techniques used to discover the new acoustic portal in toothed whales, provide a means to decipher auditory filtering, beam formation, impedance matching, and transduction. These tools can also be used to address concerns about the potential deleterious effects of high-intensity sound in a broad spectrum of marine organisms, from whales to fish. PMID:20694149

  15. Analysis of a Cartesian PML approximation to acoustic scattering problems in and

    KAUST Repository

    Bramble, James H.


    We consider the application of a perfectly matched layer (PML) technique applied in Cartesian geometry to approximate solutions of the acoustic scattering problem in the frequency domain. The PML is viewed as a complex coordinate shift ("stretching") and leads to a variable complex coefficient equation for the acoustic wave posed on an infinite domain, the complement of the bounded scatterer. The use of Cartesian geometry leads to a PML operator with simple coefficients, although, still complex symmetric (non-Hermitian). The PML reformulation results in a problem whose solution coincides with the original solution inside the PML layer while decaying exponentially outside. The rapid decay of the PML solution suggests truncation to a bounded domain with a convenient outer boundary condition and subsequent finite element approximation (for the truncated problem). This paper provides new stability estimates for the Cartesian PML approximations both on the infinite and the truncated domain. We first investigate the stability of the infinite PML approximation as a function of the PML strength σ0. This is done for PML methods which involve continuous piecewise smooth stretching as well as piecewise constant stretching functions. We next introduce a truncation parameter M which determines the size of the PML layer. Our analysis shows that the truncated PML problem is stable provided that the product of Mσ0 is sufficiently large, in which case the solution of the problem on the truncated domain converges exponentially to that of the original problem in the domain of interest near the scatterer. This justifies the simple computational strategy of selecting a fixed PML layer and increasing σ0 to obtain the desired accuracy. The results of numerical experiments varying M and σ0 are given which illustrate the theoretically predicted behavior. © 2013 Elsevier B.V. All rights reserved.

  16. International Space Station Acoustics - A Status Report (United States)

    Allen, Christopher S.


    It is important to control acoustic noise aboard the International Space Station (ISS) to provide a satisfactory environment for voice communications, crew productivity, alarm audibility, and restful sleep, and to minimize the risk for temporary and permanent hearing loss. Acoustic monitoring is an important part of the noise control process on ISS, providing critical data for trend analysis, noise exposure analysis, validation of acoustic analyses and predictions, and to provide strong evidence for ensuring crew health and safety, thus allowing Flight Certification. To this purpose, sound level meter (SLM) measurements and acoustic noise dosimetry are routinely performed. And since the primary noise sources on ISS include the environmental control and life support system (fans and airflow) and active thermal control system (pumps and water flow), acoustic monitoring will reveal changes in hardware noise emissions that may indicate system degradation or performance issues. This paper provides the current acoustic levels in the ISS modules and sleep stations and is an update to the status presented in 2011. Since this last status report, many payloads (science experiment hardware) have been added and a significant number of quiet ventilation fans have replaced noisier fans in the Russian Segment. Also, noise mitigation efforts are planned to reduce the noise levels of the T2 treadmill and levels in Node 3, in general. As a result, the acoustic levels on the ISS continue to improve.

  17. Prediction and validation of high frequency vibration repsonses of NASA Mars Pathfinder spacecraft due to acoustic launch load using statistical energy analysis (United States)

    Hwang, H. J.


    Mid and high frequency structural responses of a spacecraft during the launch condition are mainly dominated by the intense acoustic pressure field over the exterior of the launch vehicle. The prediction of structural responses due to the acoustic launch load is therefore an important analysis for engineers and scientists to correctly define various dynamics specifications of the spacecraft.

  18. Virtual Acoustics (United States)

    Lokki, Tapio; Savioja, Lauri

    The term virtual acoustics is often applied when sound signal is processed to contain features of a simulated acoustical space and sound is spatially reproduced either with binaural or with multichannel techniques. Therefore, virtual acoustics consists of spatial sound reproduction and room acoustics modeling.

  19. Advanced Wireless Power Transfer Vehicle and Infrastructure Analysis (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Gonder, J.; Brooker, A.; Burton, E.; Wang, J.; Konan, A.


    This presentation discusses current research at NREL on advanced wireless power transfer vehicle and infrastructure analysis. The potential benefits of E-roadway include more electrified driving miles from battery electric vehicles, plug-in hybrid electric vehicles, or even properly equipped hybrid electric vehicles (i.e., more electrified miles could be obtained from a given battery size, or electrified driving miles could be maintained while using smaller and less expensive batteries, thereby increasing cost competitiveness and potential market penetration). The system optimization aspect is key given the potential impact of this technology on the vehicles, the power grid and the road infrastructure.

  20. Methods for Analysis of Outdoor Performance Data (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D.


    The ability to accurately predict power delivery over the course of time is of vital importance to the growth of the photovoltaic (PV) industry. Two key cost drivers are the efficiency with which sunlight is converted to power and secondly how this relationship develops over time. The accurate knowledge of power decline over time, also known as degradation rates, is essential and important to all stakeholders--utility companies, integrators, investors, and scientists alike. Different methods to determine degradation rates and discrete versus continuous data are presented, and some general best practice methods are outlined. In addition, historical degradation rates and some preliminary analysis with respect to climate are given.

  1. AST Launch Vehicle Acoustics (United States)

    Houston, Janice; Counter, D.; Giacomoni, D.


    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  2. Parametric Analysis of Acoustical Requirements for Lateral Reflections: Melbourne Recital Hall Case Study

    Directory of Open Access Journals (Sweden)

    Erica Claustro


    Full Text Available This paper is an investigation of the Melbourne Recital Centre as a case study to define the parameters necessary for good acoustical quality as it relates to the Binaural Quality Index and determining the intimacy of the hall by its initial time delay gap. The Melbourne Recital Centre, designed by Ashton Raggatt McDougall Architects, is a significant case study, as its design was driven by the acoustic requirements of reflection and diffusion through Odeon Acoustical Software. It achieves the same acoustical quality of older, ornately designed shoebox concert halls, from the perspective of contemporary design and fabrication tools and techniques. The sleek design of the Melbourne Recital Centre successfully reflects sound waves in low, mid, and high frequencies due to corresponding wall panel differentiation in the corresponding scales, as engineered by Arup Acoustics.

  3. Room acoustics analysis using circular arrays: an experimental study based on sound field plane-wave decomposition. (United States)

    Torres, Ana M; Lopez, Jose J; Pueo, Basilio; Cobos, Maximo


    Plane-wave decomposition (PWD) methods using microphone arrays have been shown to be a very useful tool within the applied acoustics community for their multiple applications in room acoustics analysis and synthesis. While many theoretical aspects of PWD have been previously addressed in the literature, the practical advantages of the PWD method to assess the acoustic behavior of real rooms have been barely explored so far. In this paper, the PWD method is employed to analyze the sound field inside a selected set of real rooms having a well-defined purpose. To this end, a circular microphone array is used to capture and process a number of impulse responses at different spatial positions, providing angle-dependent data for both direct and reflected wavefronts. The detection of reflected plane waves is performed by means of image processing techniques applied over the raw array response data and over the PWD data, showing the usefulness of image-processing-based methods for room acoustics analysis.

  4. Failure Progress of 3D Reinforced GFRP Laminate during Static Bending, Evaluated by Means of Acoustic Emission and Vibrations Analysis

    Directory of Open Access Journals (Sweden)

    Mateusz Koziol


    Full Text Available The work aimed to assess the failure progress in a glass fiber-reinforced polymer laminate with a 3D-woven and (as a comparison plain-woven reinforcement, during static bending, using acoustic emission signals. The innovative method of the separation of the signal coming from the fiber fracture and the one coming from the matrix fracture with the use of the acoustic event’s energy as a criterion was applied. The failure progress during static bending was alternatively analyzed by evaluation of the vibration signal. It gave a possibility to validate the results of the acoustic emission. Acoustic emission, as well as vibration signal analysis proved to be good and effective tools for the registration of failure effects in composite laminates. Vibration analysis is more complicated methodologically, yet it is more precise. The failure progress of the 3D laminate is “safer” and more beneficial than that of the plain-woven laminate. It exhibits less rapid load capacity drops and a higher fiber effort contribution at the moment of the main laminate failure.

  5. Objective acoustic analysis of pathological voices from patients with vocal nodules and polyps. (United States)

    Jiang, Jack J; Zhang, Yu; MacCallum, Julia; Sprecher, Alicia; Zhou, Liang


    We aim to examine the abilities of objective acoustic analysis methods (nonlinear dynamic and traditional perturbation measures) to describe voices from individuals with vocal nodules and polyps. Sustained vowel recordings from normal subjects, patients with vocal nodules, and patients with vocal polyps were analyzed. Perturbation measures of jitter and shimmer were obtained with the Multi-Dimensional Voice Program (MDVP) and CSpeech. Signal-to-noise ratio was calculated using CSpeech. Nonlinear dynamic measures of phase space reconstruction and correlation dimension were also applied to analyze the voices. A significant difference between normal and polyp groups was found in jitter and shimmer obtained from MDVP, as well as in jitter and signal-to-noise ratio from CSpeech. However, no parameters significantly differentiated between normal and nodule groups. Shimmer from CSpeech did not reveal any significant differences among any of the groups. Correlation dimension values for the nodule and polyp groups were significantly higher than the normal group. Nonlinear dynamic analysis has great potential value for the characterization of voice from patients with vocal nodules and polyps. The combination of traditional perturbation and nonlinear dynamic measures may improve our ability to provide objective clinical analysis of voices with vocal mass lesions. Copyright 2009 S. Karger AG, Basel.

  6. A dimension-wise analysis method for the structural-acoustic system with interval parameters (United States)

    Xu, Menghui; Du, Jianke; Wang, Chong; Li, Yunlong


    The interval structural-acoustic analysis is mainly accomplished by interval and subinterval perturbation methods. Potential limitations for these intrusive methods include overestimation or interval translation effect for the former and prohibitive computational cost for the latter. In this paper, a dimension-wise analysis method is thus proposed to overcome these potential limitations. In this method, a sectional curve of the system response surface along each input dimensionality is firstly extracted, the minimal and maximal points of which are identified based on its Legendre polynomial approximation. And two input vectors, i.e. the minimal and maximal input vectors, are dimension-wisely assembled by the minimal and maximal points of all sectional curves. Finally, the lower and upper bounds of system response are computed by deterministic finite element analysis at the two input vectors. Two numerical examples are studied to demonstrate the effectiveness of the proposed method and show that, compared to the interval and subinterval perturbation method, a better accuracy is achieved without much compromise on efficiency by the proposed method, especially for nonlinear problems with large interval parameters.

  7. Acoustic propagation in the Hudson River Estuary: Analysis of experimental measurements and numerical modeling results (United States)

    Radhakrishnan, Sreeram

    Underwater intrusion detection is an ongoing security concern in port and harbor areas. Of particular interest is to detect SCUBA divers, unmanned underwater vehicles and small boats from their acoustic signature. A thorough understanding of the effects of the shallow water propagating medium on acoustic signals can help develop new technologies and improve the performance of existing acoustic based surveillance systems. The Hudson River Estuary provides us with such a shallow water medium to conduct research and improve our knowledge of shallow water acoustics. Acoustic propagation in the Hudson River Estuary is highly affected by the temporal and spatial variability of salinity and temperature due to tides, freshwater inflows, winds etc. The primary goal of this research is to help develop methodologies to predict the formation of an acoustic field in the realistic environment of the lower Hudson River Estuary. Shallow water high-frequency acoustic propagation experiments were conducted in the Hudson River near Hoboken, New Jersey. Channel Impulse Response (CIR) measurements were carried out in the frequency band from 10 to 100 kHz for distances up to 200 meters in a water depth of 8-10 meters which formed the basis for experimental Transmission Loss (TL). CIR data was also utilized to demonstrate multi-path propagation in shallow water. Acoustic propagation models based on Ray Theory and Parabolic Equation methods were implemented in the frequency band from 10 to 100 kHz and TL was estimated. The sound velocity profiles required as input by acoustic propagation models were calculated from in-situ measurements of temperature, salinity and depth. Surface reflection loss was obtained from CIR data and incorporated into the acoustic propagation models. Experimentally obtained TL was used to validate the acoustic model predictions. An outcome of this research is an operational acoustic transmission loss (TL) forecast system based on the existing, Stevens New York

  8. Interactions in an acoustic world

    CERN Document Server

    Simaciu, Ion; Borsos, Zoltan; Bradac, Mariana


    The present paper aims to complete an earlier paper where the acoustic world was introduced. This is accomplished by analyzing the interactions which occur between the inhomogeneities of the acoustic medium, which are induced by the acoustic vibrations traveling in the medium. When a wave packet travels in a medium, the medium becomes inhomogeneous. The spherical wave packet behaves like an acoustic spherical lens for the acoustic plane waves. According to the principle of causality, there is an interaction between the wave and plane wave packet. In specific conditions the wave packet behaves as an acoustic black hole.

  9. Integration of acoustic emission systems within Integri-TechTM analysis system for structural health monitoring of pressurised engineering plant (United States)

    Ghouri, A. A.; Rafferty, Steven; Pickwell, Andy; Galbraith, Walter; Pierce, S. Gareth; Gachagan, Anthony


    The aim of this Acoustic Emission (AE) based Structural Health Monitoring project is to enable accurate location of AE sources in pressurised engineering plant and to use AE source location data to establish defect locations for use within Integri-TechTM; a finite element based analysis, monitoring and fitness for service assessment system. Integri-TechTM is a windows based system which carries out combined analysis and assessment providing fatigue life and remnant life calculations and inspection priorities presenting the results in an accessible web portal format. The software uses finite element stress models created in the companion software Model Wizard. The AE monitoring system that has been developed can be used with an array of up to four AE broad band sensor channels with associated signal processing. Using a flexible approach in MATLAB, the authors have developed algorithms which were used for analysing the received AE signals to extract information about the nature and location of the source. The ability to carry out source location and possibly perform real time monitoring (detecting cracking as it occurs) is attractive feature of the AE system developed for this project. The time of arrival (TOA) data was used by Integri-TechTM software to calculate source location using its own built-in algorithm, and this was verified independently using a MATLAB approach.

  10. Speech and language disorders secondary to diffuse subcortical vascular lesions: Neurolinguistic and acoustic analysis. A case report. (United States)

    Tomić, Gordana; Stojanović, Milena; Pavlović, Aleksandra; Stanković, Predrag; Zidverc-Trajković, Jasna; Pavlović, Dragan; Marković-Jovanović, Zagorka; Covicković-Sternić, Nadezda


    Subcortical white matter (WM) plays an important role in speech production and language processing. Most frequently, cerebral WM lesions are secondary to small vessel disease in patients with vascular risk factors. We report the case of a 53-year-old man with history of hypertension and ischemic subcortical lesions, who presented with speech difficulties and mild cognitive impairment. Language and cognitive assessment included Boston Diagnostic Aphasia Examination, Boston Naming Test, Rey Auditory-Verbal Learning Test, Rey-Osterrieth Complex Figure Test, Trail Making Test A and B, Wisconsin Card Sorting Test, Scale for Evaluation of Perceptive Characteristics of Voice and Speech, and Multidimensional Evaluation of Speech and Voice. Brain MRI showed ischemic WM lesions and lacunar infarcts in the brainstem and right cerebellum. Cognitive testing revealed mild cognitive impairment, predominantly affecting attention and executive functions. Speech and language analysis demonstrated dysarthria, dysphonia with hypophonia, and imprecise articulation, as well as short rushes of speech, palilalia and mild subcortical dysphasia. Neurolinguistic and acoustic analysis in patients with ischemic WM lesions can provide additional information in the understanding of language and speech disturbances, and can assist in patient management.

  11. Analysis of Surfing Injuries Presenting in the Acute Trauma Setting. (United States)

    Jubbal, Kevin T; Chen, Charlie; Costantini, Todd; Herrera, Fernando; Dobke, Marek; Suliman, Ahmed


    Surfing is a rapidly growing major worldwide sport; however, little is understood regarding severe injuries and resulting hospital admissions. This study explores surfing-related injuries in the major surfing hub of San Diego presenting in the acute trauma setting. The purpose of this study is to address the void of information regarding severe surfing injuries in the trauma setting, including injury patterns, associated hospitalization course, and risk factors. Understanding the injury patterns in surfing accidents is crucial for proper management of surfing injuries. A retrospective analysis was performed of all surfing-related injuries in a Level 1 trauma center between 2000 and 2016. A total of 93 patients were identified. Body parts most commonly affected include the head (42, 46%), face (21, 22%), and spine (47, 51%). Twenty-eight (30%) patients required surgical intervention, including 19 for spinal injuries, 3 for facial injuries, 4 for upper extremity injuries, and 2 for lower extremity injuries. The distribution for most presentations (55, 59%) occurred in the summer months between July and September. The Injury Severity Score demonstrated strong positive correlation with the length of hospital stay, with a Pearson coefficient of 0.52 (P injuries in patients presenting with surfing injuries in the trauma setting, consistent with its presentation as a high velocity and high impact injury. With plastic surgeons often treating severe head and facial injuries, understanding the injury patterns in severe surfing accidents is crucial for proper management. High rates of positive alcohol and drug screening signal the importance to bring awareness to the dangers of surfing under the influence.

  12. Design, analysis and presentation of factorial randomised controlled trials

    Directory of Open Access Journals (Sweden)

    Little Paul


    Full Text Available Abstract Background The evaluation of more than one intervention in the same randomised controlled trial can be achieved using a parallel group design. However this requires increased sample size and can be inefficient, especially if there is also interest in considering combinations of the interventions. An alternative may be a factorial trial, where for two interventions participants are allocated to receive neither intervention, one or the other, or both. Factorial trials require special considerations, however, particularly at the design and analysis stages. Discussion Using a 2 × 2 factorial trial as an example, we present a number of issues that should be considered when planning a factorial trial. The main design issue is that of sample size. Factorial trials are most often powered to detect the main effects of interventions, since adequate power to detect plausible interactions requires greatly increased sample sizes. The main analytical issues relate to the investigation of main effects and the interaction between the interventions in appropriate regression models. Presentation of results should reflect the analytical strategy with an emphasis on the principal research questions. We also give an example of how baseline and follow-up data should be presented. Lastly, we discuss the implications of the design, analytical and presentational issues covered. Summary Difficulties in interpreting the results of factorial trials if an influential interaction is observed is the cost of the potential for efficient, simultaneous consideration of two or more interventions. Factorial trials can in principle be designed to have adequate power to detect realistic interactions, and in any case they are the only design that allows such effects to be investigated.

  13. Mobility power flow analysis of coupled plate structure subjected to mechanical and acoustic excitation (United States)

    Cuschieri, J. M.


    The mobility power flow approach that was previously applied in the derivation of expressions for the vibrational power flow between coupled plate substructures forming an L configuration and subjected to mechanical loading is generalized. Using the generalized expressions, both point and distributed mechanical loads on one or both of the plates can be considered. The generalized approach is extended to deal with acoustic excitation of one of the plate substructures. In this case, the forces (acoustic pressures) acting on the structure are dependent on the response of the structure because of the scattered pressure component. The interaction between the plate structure and the acoustic fluid leads to the derivation of a corrected mode shape for the plates' normal surface velocity and also for the structure mobility functions. The determination of the scattered pressure components in the expressions for the power flow represents an additional component in the power flow balance for the source plate and the receiver plate. This component represents the radiated acoustical power from the plate structure. For a number of coupled plate substrates, the acoustic pressure generated by one substructure will interact with the motion of another substructure. That is, in the case of the L-shaped plate, acoustic interaction exists between the two plate substructures due to the generation of the acoustic waves by each of the substructures. An approach to deal with this phenomena is described.

  14. 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 chapt......: acoustics, cognitive science, speech science, and communication technology.......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...

  15. Acoustic Analysis of Composite Soft Materials IV.Evaluation of Compressibility of Bound Rubber in Carbon Black Filled SBR (United States)

    Maebayashi, Masahiro; Endo, Masashi; Matsuoka, Tatsuro; Koda, Shinobu; Isono, Yoshinobu

    A carbon black (CB) filled styrene-butadiene rubber (SBR) compound was investigated by acoustic techniques, scanning acoustic microscopy and longitudinal wave velocitometry. The CB agglomerates of larger than 5 µm dispersed in the compound mixed by two-roll mill were observed as black spots in acoustic micrographs. On the other hand, the CB agglomerates in the compound mixed by oil-pressure kneader were not observed in the acoustic micrograph, since the particle size of the agglomerates was less than 5 µm. The density and the longitudinal wave velocity of the compound were measured as a function of the weight percentage of the CB. The density and the velocity increased linearly with the content of the CB. The mass ratio of the bound rubber to the CB in the unvulcanized sample was determined by using toluene extraction and thermo gravimetric analysis. The partial specific adiabatic compressibility of the CB was estimated as (-0.5±0.5)×10-10 Pa-1 on the basis of the three states model. The adiabatic compressibility of the bound rubber was (2.2±0.5)×10-10 Pa-1, and it is half of that of the SBR matrix.

  16. Monitoring of Global Acoustic Transmissions: Signal Processing and Preliminary Data Analysis (United States)


    signal level and 6.39x10- I volts2/Hz for the noise value. These values can be converted to acoustic power levels of 19 dB rel ipPa for the signal and...46.4 dB rel ipPa for the noise, as discussed below. Transmission loss over the mean acoustic path would then be about 213 dB - 19 dB = 194 dB. b. Signal...sensitivity of the hydrophones (-170 Db rel IpPa or 3.162 x 108 pPa/V). Acoustic power is the pressure force times the velocity of the pressure wave

  17. Implementation of Bipolar Adjective Pairs in Analysis of Urban Acoustic Environments

    Directory of Open Access Journals (Sweden)

    Mia Suhanek


    Full Text Available Four different acoustic environments with different loudness levels and spectral distributions were recorded and reproduced to two groups of listeners - control group and experimental group. The questionnaire used in this research relies on the semantic differential method implemented by defining adjective pairs of opposite meaning where each pair describes a sound characteristic for a particular acoustic environment. In analyzing the results, psychological research methodology was used in order to determine statistically significant bipolar adjectives that can appropriately evaluate some given acoustic environment and thus serve as a starting point for a questionnaire and methodology standardization in soundscape research.



    Pavarin, Cora


    In the present work various aspects of the energetic, thermal and acoustic properties of porous materials with wood wool mineralized Portland cement have been analyzed, in cooperation with the company Celenit Srl, a manufacturer of panels for building insulation. These products are also recognized interesting and desirable for their environmental sustainability through specific certifications. Remind that sustainability means "development that meets the needs of the present without comprom...

  19. An analysis of present dental professions in Sweden. (United States)

    Ordell, Sven; Unell, Lennart; Söderfeldt, Björn


    Dentistry in Sweden is predicted to have a shortage of dentists in the future and the division of labour within dentistry will be a more debated question. In order to forecast the effects of such a shortage the professional status of the involved groups must be made clearer. The objective of this paper is to analyse the emergence and present professional status of clinical dental professions in Sweden. The study was conducted on the basis of theories on professions, and their roles in organizations was analysed. The results were applied on the historical emergence, establishment and consolidation of clinical dental professions in Sweden. The results show that a large sector of salaried dentists has not diminished the professional status of the Swedish dentists. Professional ambitions such as many clinical subspecialties and a strong element of research have not been restrained by the public health ambitions in the Public Dental Health Service (PDHS). Presently, other dental professions are dental hygienists, dental technicians and dental nurses. Of these the only other licensed group, the dental hygienists, are an emerging profession. They have an uphill struggle to obtain a full professional status, mainly because their knowledge domains are neither specific nor exclusive to their group. Development of a common core curriculum on a clearly academic level would enhance their professional status. Dental technicians and nurses are lacking fundamental traits as professions. There appears to be little need for additional groups of clinical professions besides dentists and dental hygienists in Swedish dentistry. In conclusion,this analysis provided better understanding of the present status of the Swedish dental professions, to prepare for future restructuring of the dental care system. Further work will be needed to understand the impact of professional traits on the management of groups of professionals.

  20. Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Finite size correction by image sources (United States)

    Alimonti, L.; Atalla, N.


    This work is concerned with the hybrid finite element-transfer matrix methodology recently proposed by the authors. The main assumption behind this hybrid method consists in neglecting the actual finite lateral extent of the acoustic treatment. Although a substantial increase of the computational efficiency can be achieved, the effect of the reflected field (i.e. finite size effects) may be sometimes important, preventing the hybrid model from giving quantitative meaningful results. For this reason, a correction to account for wave reflections at the lateral boundaries of the acoustic treatment is sought. It is shown in the present paper that the image source method can be successfully employed to retrieve such finite size effects. Indeed, such methodology is known to be effective when the response of the system is a smooth function of the frequency, like in the case of highly dissipative acoustic treatments. The main concern of this paper is to assess accuracy and feasibility of the image source method in the context of acoustic treatments modeling. Numerical examples show that the performance of the standard hybrid model can be substantially improved by the proposed correction without deteriorating excessively the computational efficiency.

  1. 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....

  2. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    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......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......: acoustics, cognitive science, speech science, and communication technology....

  3. 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......: acoustics, cognitive science, speech science, and communication technology....... 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...

  4. Analysis of the effect of a rectangular cavity resonator on acoustic wave transmission in a waveguide (United States)

    Porter, R.; Evans, D. V.


    The transmission of acoustic waves along a two-dimensional waveguide which is coupled through an opening in its wall to a rectangular cavity resonator is considered. The resonator acts as a classical band-stop filter, significantly reducing acoustic transmission across a range of frequencies. Assuming wave frequencies below the first waveguide cut-off, the solution for the reflected and transmitted wave amplitudes is formulated exactly within the framework of inviscid linear acoustics. The main aim of the paper is to develop an approximation in closed form for reflected and transmitted amplitudes when the gap in the thin wall separating the waveguide and the cavity resonator is assumed to be small. This approximation is shown to accurately capture the effect of all cavities resonances, not just the fundamental Helmholtz resonance. It is envisaged this formula (and more generally the mathematical approach adopted) could be used in the development of acoustic metamaterial devices containing resonator arrays.

  5. Analysis, Design, and Evaluation of Acoustic Feedback Cancellation Systems for Hearing Aids

    DEFF Research Database (Denmark)

    Guo, Meng


    Acoustic feedback problems occur when the output loudspeaker signal of an audio system is partly returned to the input microphone via an acoustic coupling through the air. This problem often causes significant performance degradations in applications such as public address systems and hearing aids....... In the worst case, the audio system becomes unstable and howling occurs. In this work, first we analyze a general multiple microphone audio processing system, where a cancellation system using adaptive filters is used to cancel the effect of acoustic feedback. We introduce and derive an accurate approximation...... in acoustic feedback cancellation for hearing aids. It utilizes a probe noise signal which is generated with a specific characteristic so that it can facilitate an unbiased adaptive filter estimation with fast tracking of feedback path variations/changes despite its low signal level. We show in a hearing aid...

  6. Chronological analysis of architectural and acoustical indices in music performance halls. (United States)

    Kwon, Youngmin; Siebein, Gary W


    This study aims to identify the changes in architectural and acoustical indices in halls for music performance built in the 18th through the 20th Centuries. Seventy-one halls are classified in five specific periods from the Classical Period (1751-1820) to the Contemporary Period (1981-2000) based on chronology in music and architectural acoustics. Architectural indices such as room shape, seating capacity, room volume, balcony configuration, and the like as well as acoustical indices such as RT, EDT, G, C80, IACC, and the like for the halls found in the literature are chronologically tabulated and statistically analyzed to identify trends and relationships in architectural and acoustical design for each of the historical periods identified. Some indices appear correlated with each other.

  7. Perceptual and acoustic analysis of lexical stress in Greek speakers with dysarthria. (United States)

    Papakyritsis, Ioannis; Müller, Nicole


    The study reported in this paper investigated the abilities of Greek speakers with dysarthria to signal lexical stress at the single word level. Three speakers with dysarthria and two unimpaired control participants were recorded completing a repetition task of a list of words consisting of minimal pairs of Greek disyllabic words contrasted by lexical stress location only. Fourteen listeners were asked to determine the attempted stress location for each word pair. Acoustic analyses of duration and intensity ratios, both within and across words, were undertaken to identify possible acoustic correlates of the listeners' judgments concerning stress location. Acoustic and perceptual data indicate that while each participant with dysarthria in this study had some difficulty in signaling stress unambiguously, the pattern of difficulty was different for each speaker. Further, it was found that the relationship between the listeners' judgments of stress location and the acoustic data was not conclusive.

  8. Seeing Sound - Image Analysis of the Lift-off Acoustic Field Project (United States)

    National Aeronautics and Space Administration — A launch vehicle and its launch facilities are subjected to intense acoustic loads generated by the vehicle's propulsion system. The vehicle, its payload, and...

  9. Objective approach for analysis of noise source characteristics and acoustic conditions in noisy computerized embroidery workrooms. (United States)

    Aliabadi, Mohsen; Golmohammadi, Rostam; Mansoorizadeh, Muharram


    It is highly important to analyze the acoustic properties of workrooms in order to identify best noise control measures from the standpoint of noise exposure limits. Due to the fact that sound pressure is dependent upon environments, it cannot be a suitable parameter for determining the share of workroom acoustic characteristics in producing noise pollution. This paper aims to empirically analyze noise source characteristics and acoustic properties of noisy embroidery workrooms based on special parameters. In this regard, reverberation time as the special room acoustic parameter in 30 workrooms was measured based on ISO 3382-2. Sound power quantity of embroidery machines was also determined based on ISO 9614-3. Multiple linear regression was employed for predicting reverberation time based on acoustic features of the workrooms using MATLAB software. The results showed that the measured reverberation times in most of the workrooms were approximately within the ranges recommended by ISO 11690-1. Similarity between reverberation time values calculated by the Sabine formula and measured values was relatively poor (R (2) = 0.39). This can be due to the inaccurate estimation of the acoustic influence of furniture and formula preconditions. Therefore, this value cannot be considered representative of an actual acoustic room. However, the prediction performance of the regression method with root mean square error (RMSE) = 0.23 s and R (2) = 0.69 is relatively acceptable. Because the sound power of the embroidery machines was relatively high, these sources get the highest priority when it comes to applying noise controls. Finally, an objective approach for the determination of the share of workroom acoustic characteristics in producing noise could facilitate the identification of cost-effective noise controls.

  10. The expression and recognition of emotions in the voice across five nations: A lens model analysis based on acoustic features. (United States)

    Laukka, Petri; Elfenbein, Hillary Anger; Thingujam, Nutankumar S; Rockstuhl, Thomas; Iraki, Frederick K; Chui, Wanda; Althoff, Jean


    This study extends previous work on emotion communication across cultures with a large-scale investigation of the physical expression cues in vocal tone. In doing so, it provides the first direct test of a key proposition of dialect theory, namely that greater accuracy of detecting emotions from one's own cultural group-known as in-group advantage-results from a match between culturally specific schemas in emotional expression style and culturally specific schemas in emotion recognition. Study 1 used stimuli from 100 professional actors from five English-speaking nations vocally conveying 11 emotional states (anger, contempt, fear, happiness, interest, lust, neutral, pride, relief, sadness, and shame) using standard-content sentences. Detailed acoustic analyses showed many similarities across groups, and yet also systematic group differences. This provides evidence for cultural accents in expressive style at the level of acoustic cues. In Study 2, listeners evaluated these expressions in a 5 × 5 design balanced across groups. Cross-cultural accuracy was greater than expected by chance. However, there was also in-group advantage, which varied across emotions. A lens model analysis of fundamental acoustic properties examined patterns in emotional expression and perception within and across groups. Acoustic cues were used relatively similarly across groups both to produce and judge emotions, and yet there were also subtle cultural differences. Speakers appear to have a culturally nuanced schema for enacting vocal tones via acoustic cues, and perceivers have a culturally nuanced schema in judging them. Consistent with dialect theory's prediction, in-group judgments showed a greater match between these schemas used for emotional expression and perception. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  11. TU-G-210-03: Acoustic Simulations in Transcranial MRgFUS: Treatment Prediction and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, U. [Stanford University (United States)


    Modeling can play a vital role in predicting, optimizing and analyzing the results of therapeutic ultrasound treatments. Simulating the propagating acoustic beam in various targeted regions of the body allows for the prediction of the resulting power deposition and temperature profiles. In this session we will apply various modeling approaches to breast, abdominal organ and brain treatments. Of particular interest is the effectiveness of procedures for correcting for phase aberrations caused by intervening irregular tissues, such as the skull in transcranial applications or inhomogeneous breast tissues. Also described are methods to compensate for motion in targeted abdominal organs such as the liver or kidney. Douglas Christensen – Modeling for Breast and Brain HIFU Treatment Planning Tobias Preusser – TRANS-FUSIMO - An Integrative Approach to Model-Based Treatment Planning of Liver FUS Urvi Vyas – Acoustic Simulations in Transcranial MRgFUS: Treatment Prediction and Analysis Learning Objectives: Understand the role of acoustic beam modeling for predicting the effectiveness of therapeutic ultrasound treatments. Apply acoustic modeling to specific breast, liver, kidney and transcranial anatomies. Determine how to obtain appropriate acoustic modeling parameters from clinical images. Understand the separate role of absorption and scattering in energy delivery to tissues. See how organ motion can be compensated for in ultrasound therapies. Compare simulated data with clinical temperature measurements in transcranial applications. Supported by NIH R01 HL172787 and R01 EB013433 (DC); EU Seventh Framework Programme (FP7/2007-2013) under 270186 (FUSIMO) and 611889 (TRANS-FUSIMO)(TP); and P01 CA159992, GE, FUSF and InSightec (UV)

  12. Acoustic constituents of prosodic typology (United States)

    Komatsu, Masahiko

    Different languages sound different, and considerable part of it derives from the typological difference of prosody. Although such difference is often referred to as lexical accent types (stress accent, pitch accent, and tone; e.g. English, Japanese, and Chinese respectively) and rhythm types (stress-, syllable-, and mora-timed rhythms; e.g. English, Spanish, and Japanese respectively), it is unclear whether these types are determined in terms of acoustic properties, The thesis intends to provide a potential basis for the description of prosody in terms of acoustics. It argues for the hypothesis that the source component of the source-filter model (acoustic features) approximately corresponds to prosody (linguistic features) through several experimental-phonetic studies. The study consists of four parts. (1) Preliminary experiment: Perceptual language identification tests were performed using English and Japanese speech samples whose frequency spectral information (i.e. non-source component) is heavily reduced. The results indicated that humans can discriminate languages with such signals. (2) Discussion on the linguistic information that the source component contains: This part constitutes the foundation of the argument of the thesis. Perception tests of consonants with the source signal indicated that the source component carries the information on broad categories of phonemes that contributes to the creation of rhythm. (3) Acoustic analysis: The speech samples of Chinese, English, Japanese, and Spanish, differing in prosodic types, were analyzed. These languages showed difference in acoustic characteristics of the source component. (4) Perceptual experiment: A language identification test for the above four languages was performed using the source signal with its acoustic features parameterized. It revealed that humans can discriminate prosodic types solely with the source features and that the discrimination is easier as acoustic information increases. The

  13. Surface acoustic wave sensor array system for trace organic vapor detection using pattern recognition analysis (United States)

    Rose-Pehrsson, Susan L.; Grate, Jay W.; Klusty, Mark


    A sensor system using surface acoustic wave (SAW) vapor sensors has been fabricated and tested against hazardous organic vapors, simulants of these vapors, and potential background vapors. The vapor tests included two- and three-component mixtures, and covered a wide relative humidity range. The sensor system was compared of four SAW devices coated with different sorbent materials with different vapor selectivities. Preconcentrators were included to improve sensitivity. The vapor experiments were organized into a large data set analyzed using pattern recognition techniques. Pattern recognition algorithms were developed to identify two different classes of hazards. The algorithms were verified against a second data set not included in the training. Excellent sensitivity was achieved by the sensor coatings, and the pattern recognition analysis, and was also examined by the preconcentrators. The system can detect hazardous vapors of interest in the ppb range even in varying relative humidity and in the presence of background vapors. The system does not false alarm to a variety of other vapors including gasoline, jet fuel, diesel fuel and cigarette smoke.

  14. Adjuvant use of acoustic pressure wound therapy for treatment of chronic wounds: a retrospective analysis. (United States)

    Cole, Pamela S; Quisberg, Jennifer; Melin, M Mark


    Small studies have indicated that the addition of acoustic pressure wound therapy (APWT) to conventional wound care may hasten healing of chronic wounds. We evaluated our early clinical experience using APWT as an adjunct to conventional wound care. The study was a retrospective chart review of consecutive patients receiving APWT in addition to conventional wound care in a hospital-based, primarily outpatient setting. Medical records of all patients treated with APWT between August 2006 and October 2007 were reviewed. Analysis included the 41 patients with 52 wounds who received APWT at least 2 times per week during the study period. Statistical comparisons were made for wound dimensions, tissue characteristics, and pain at start versus end of APWT. Thirty-eight percent of wounds (N = 20) healed completely with a mean 6.8 weeks of APWT. Median wound area and volume decreased significantly (88% [P wounds with greater than 75% granulation tissue increased from 26% (n = 12) to 80% (n = 41) (P wounds (P = .006). This early experience supplementing conventional wound care with APWT suggests it may promote healing in chronic wounds, where the ordered cellular and molecular processes leading to healing have stalled.

  15. Protection of window glass from acoustic leakage


    Lych, Sergij; Rakobovchuk, Volodymyr


    In a survey was presented an analysis of the most common glass samples on the Ukrainian market on their protection level against leakage of acoustic information. The glass samples were studied by means of roentgen analysis, and the impact of elemental composition of glass according to a laser beam reflection factor was defined.

  16. Acoustic Signals and Systems

    DEFF Research Database (Denmark)


    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...... from different areas, will find the self-contained chapters accessible and will be interested in the similarities and differences between the approaches and techniques used in different areas of acoustics....

  17. Computational Ocean Acoustics

    CERN Document Server

    Jensen, Finn B; Porter, Michael B; Schmidt, Henrik


    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...

  18. Numerical analysis of the transportation characteristics of a self-running sliding stage based on near-field acoustic levitation. (United States)

    Feng, Kai; Liu, Yuanyuan; Cheng, Miaomiao


    Owing to its distinct non-contact and oil-free characteristics, a self-running sliding stage based on near-field acoustic levitation can be used in an environment, which demands clean rooms and zero noise. This paper presents a numerical analysis on the lifting and transportation capacity of a non-contact transportation system. Two simplified structure models, namely, free vibration and force vibration models, are proposed for the study of the displacement amplitude distribution of two cases using the finite element method. After coupling the stage displacement into the film thickness, the Reynolds equation is solved by the finite difference method to obtain the lifting and thrusting forces. Parametric analyses of the effects of amplitude, frequency, and standing wave ratio (SWR) on the sliding stage dynamic performance are investigated. Numerical results show good agreement with published experimental values. The predictions also reveal that greater transportation capacity of the self-running sliding stage is generally achieved at less SWR and at higher amplitude.

  19. Acoustic Neuroma (United States)

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  20. A Short Integrated Presentation of Valuation, Profitability and Growth Analysis

    DEFF Research Database (Denmark)

    Pettersson, Kim; Sørensen, Ole


    We demonstrate how the valuation models used in finance theory and the profitability and growth analysis taught in financial statement analysis are related. Traditional textbooks on finance and financial statement analysis are often very comprehensive, comprising a vast number of chapters. Howeve...

  1. Analysis of acoustic emission signals at austempering of steels using neural networks (United States)

    Łazarska, Malgorzata; Wozniak, Tadeusz Z.; Ranachowski, Zbigniew; Trafarski, Andrzej; Domek, Grzegorz


    Bearing steel 100CrMnSi6-4 and tool steel C105U were used to carry out this research with the steels being austempered to obtain a martensitic-bainitic structure. During the process quite a large number of acoustic emissions (AE) were observed. These signals were then analysed using neural networks resulting in the identification of three groups of events of: high, medium and low energy and in addition their spectral characteristics were plotted. The results were presented in the form of diagrams of AE incidence as a function of time. It was demonstrated that complex transformations of austenite into martensite and bainite occurred when austempering bearing steel at 160 °C and tool steel at 130 °C respectively. The selected temperatures of isothermal quenching of the tested steels were within the area near to MS temperature, which affected the complex course of phase transition. The high activity of AE is a typical occurrence for martensitic transformation and this is the transformation mechanism that induces the generation of AE signals of higher energy in the first stage of transition. In the second stage of transformation, the initially nucleated martensite accelerates the occurrence of the next bainitic transformation.

  2. An improved method and data analysis for ultrasound acoustic emissions and xylem vulnerability in conifer wood. (United States)

    Wolkerstorfer, Silviya V; Rosner, Sabine; Hietz, Peter


    The vulnerability of the xylem to cavitation is an important trait in plant drought resistance and has been quantified by several methods. We present a modified method for the simultaneous measurement of cavitations, recorded as ultrasound acoustic emissions (UAEs), and the water potential, measured with a thermocouple psychrometer, in small samples of conifer wood. Analyzing the amplitude of the individual signals showed that a first phase, during which the mean amplitude increased, was followed by a second phase with distinctly lower signal amplitudes. We provide a method to separate the two groups of signals and show that for many samples plausible vulnerability curves require rejecting late low-energy UAEs. These very likely do not result from cavitations. This method was used to analyze the differences between juvenile wood, and early and late mature wood in Picea abies (L.) Karst. Juvenile earlywood was more resistant to cavitation than mature earlywood or latewood, which we relate to the tracheid anatomy of the samples. Copyright © Physiologia Plantarum 2012.

  3. 5 Percent Ares I Scale Model Acoustic Test: Overpressure Characterization and Analysis (United States)

    Alvord, David; Casiano, Matthew; McDaniels, Dave


    During the ignition of a ducted solid rocket motor (SRM), rapid expansion of injected hot gases from the motor into a confined volume causes the development of a steep fronted wave. This low frequency transient wave propagates outward from the exhaust duct, impinging the vehicle and ground structures. An unsuppressed overpressure wave can potentially cause modal excitation in the structures and vehicle, subsequently leading to damage. This presentation details the ignition transient f indings from the 5% Ares I Scale Model Acoustic Test (ASMAT). The primary events of the ignition transient environment induced by the SRM are the ignition overpressure (IOP), duct overpressure (DOP), and source overpressure (SOP). The resulting observations include successful knockdown of the IOP environment through use of a Space Shuttle derived IOP suppression system, a potential load applied to the vehicle stemming from instantaneous asymmetrical IOP and DOP wave impingement, and launch complex geometric influences on the environment. The results are scaled to a full-scale Ares I equivalent and compared with heritage data including Ares I-X and both suppressed and unsuppressed Space Shuttle IOP environments.



    Lyamshev, L.


    Radiation acoustics is a new branch of acoustics. Its' fundamentals are lying in the research of acoustical effects due to the interaction of a radiation with matter. The sound excitation in liquids and solids by modulated or pulsed particle beams (electron, proton, ion beams, γ-radiation and single high-energy elementary particles) and some practical applications are discussed.

  5. Charisma in business speeches:A contrastive acoustic-prosodic analysis of Steve Jobs and Mark Zuckerberg


    Niebuhr, Oliver; Brem, Alexander; Novák-Tót, Eszter; Voße, Jana


    Charisma is a key component of spoken language interaction; and it is probably for this reason that charismatic speech has been the subject of intensive research for centuries. However, what is still largely missing is a quantitative and objective line of research that, firstly, involves analyses of the acoustic-prosodic signal, secondly, focuses on business speeches like product presentations, and, thirdly, in doing so, advances the still fairly fragmentary evidence on the prosodic correlate...

  6. Acoustic correlates of Georgian ejectives (United States)

    Wysocki, Tamra M.


    In this paper we present results from acoustic analysis of Georgian ejectives. Georgian, a language of the Kartvelian (South Caucasian) family, has a three-way opposition for voiced, voiceless aspirated and ejective stops. There have not been many acoustic studies of ejectives; those studies that discuss ejectives, such as by Lindau [J. Phonetics 12, 147-155 (1984)], report cross-linguistic variation in timing between oral and glottal releases and the onset of a following vowel. In this paper we investigate acoustic correlates of Georgian ejectives and examine how these correlates are realized in two-member ejective clusters. Additionally, correlates of Georgian ejectives are compared to findings from previous studies and discussed in relation to cross-linguistic tendencies and variation. Data consist of field recordings of three native Georgian speakers producing single ejectives and ejective clusters in word-initial and word-medial (intervocalic) positions at a normal rate of speech. Acoustic analysis was completed using spectrograms and waveforms. Results indicate that, while there is variation within and among speakers, characteristics correlated with singleton Georgian ejectives include relative burst amplitude, noise quality following oral release, long, positive voice onset time, and a short period of creaky voice at the onset of a following vowel. Some of these characteristics differ from those of ejective clusters.

  7. Qualitative analysis of the positron-acoustic waves in electron-positron-ion plasmas with κ deformed Kaniadakis distributed electrons and hot positrons (United States)

    Saha, Asit; Tamang, Jharna


    Qualitative analysis of the positron acoustic (PA) waves in a four-component plasma system consisting of static positive ions, mobile cold positron, and Kaniadakis distributed hot positrons and electrons is investigated. Using the reductive perturbation technique, the Korteweg-de Vries (K-dV) equation and the modified KdV equation are derived for the PA waves. Variations of the total energy of the conservative systems corresponding to the KdV and mKdV equations are presented. Applying numerical computations, effect of parameter (κ), number density ratio (μ1) of electrons to ions and number density (μ2) of hot positrons to ions, and speed (U) of the traveling wave are discussed on the positron acoustic solitary wave solutions of the KdV and mKdV equations. Furthermore, it is found that the parameter κ has no effect on the solitary wave solution of the KdV equation, whereas it has significant effect on the solitary wave solution of the modified KdV equation. Considering an external periodic perturbation, the perturbed dynamical systems corresponding to the KdV and mKdV equations are analyzed by employing three dimensional phase portrait analysis, time series analysis, and Poincare section. Chaotic motions of the perturbed PA waves occur through the quasiperiodic route to chaos.

  8. Distribution of Acoustic Power Spectra for an Isolated Helicopter Fuselage

    Directory of Open Access Journals (Sweden)

    Kusyumov A.N.


    Full Text Available The broadband aerodynamic noise can be studied, assuming isotropic flow, turbulence and decay. Proudman’s approach allows practical calculations of noise based on CFD solutions of RANS or URANS equations at the stage of post processing and analysis of the solution. Another aspect is the broadband acoustic spectrum and the distribution of acoustic power over a range of frequencies. The acoustic energy spectrum distribution in isotropic turbulence is non monotonic and has a maximum at a certain value of Strouhal number. In the present work the value of acoustic power peak frequency is determined using a prescribed form of acoustic energy spectrum distribution presented in papers by S. Sarkar and M. Y. Hussaini and by G. M. Lilley. CFD modelling of the flow around isolated helicopter fuselage model was considered using the HMB CFD code and the RANS equations.

  9. Large-eddy simulation and acoustic analysis of a turbulent flow field in a swirl-stabilized combustor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Chan; Yoo, Kwang Hee; Sung, Hong Gye [Korea Aerospace University, Goyang (Korea, Republic of)


    To conduct a comprehensive study on the flow characteristics and acoustic oscillation in a gas turbine combustor, a 3D large-eddy simulation (LES) was implemented. The formulation consists of the Favre-filtered conservation equations of mass, momentum, and energy. The subgrid-scale dynamics are modeled using a compressible flow version of the Smagorinsky model. To investigate the dominant coherent structure, the proper orthogonal decomposition (POD) method was used for post-processing. The combustor of concern is the LM6000, lean-premixed dry low-NOx annular combustor, developed by General Electric Aircraft Engines (GEAE). Four important characteristics of swirl flow are visualized: vortex breakdown, procession and dissipation of vortical structures, recirculation zones, and helical waves immediately downstream of the swirl injector. It is shown that the turbulent motion of swirl flow directly affects acoustic oscillation through the cycle and spectral analysis. The four most dominant acoustic modes are extracted from the flow field by the POD analysis. The transverse modes in the y and z directions are dominant in all four modes, since the pressure fields are significantly affected by swirl flow.

  10. Acoustic emission analysis for structural health monitoring of hot metal components; Schallemissionsanalyse zur Zustandsueberwachung von heissen Metallkomponenten

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Eberhard [Fraunhofer-Institut fuer Keramische Technologien und Systeme, Dresden (Germany). Institutsteil Materialdiagnostik


    For the application of acoustic emission analysis on hot components such as pipes special application techniques are necessary to protect the sensor from the heat. The Fraunhofer IKTS-MD has developed a waveguide solution that meets these requirements. Major challenges in the application of acoustic emission analysis in an industrial environment is the strong ambient noise. This requirement meets the developed acoustic measurement system at the Fraunhofer Institute by a high measurement dynamics, storage and assessment of the complete waveforms and by special algorithms. The attractiveness of the method lies in the relatively low number of sensors with which the integrity of large plant areas (e.g. several meters under high alternating load standing superheated steam pipe) can be permanently monitored. [German] Fuer die Anwendung der Schallemissionsanalyse an heissen Komponenten wie Rohrleitungen sind besondere Applikationstechniken notwendig, um den Sensor vor der Hitze zu schuetzen. Das Fraunhofer IKTS-MD hat dafuer eine Wellenleiterloesung entwickelt, die diese Anforderungen erfuellt. Wesentliche Herausforderung bei der Anwendung der Schallemissionsanalyse in industrieller Umgebung ist das starke Umgebungsrauschen. Dieser Anforderung begegnet das am Fraunhofer-Institut entwickelte akustische Messsystem durch eine hohe Messwertdynamik, Speicherung und Bewertung der vollstaendigen Wellenformen sowie durch spezielle Auswertealgorithmen. Die Attraktivitaet des Verfahrens liegt in der vergleichsweise geringen Anzahl von Sensoren, mit denen die Integritaet grosser Anlagenbereiche (z.B. mehrere Meter unter hoher Wechsellast stehender Heissdampfleitung) dauerhaft ueberwacht werden kann.

  11. Acoustic MIMO signal processing

    CERN Document Server

    Huang, Yiteng; Chen, Jingdong


    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.

  12. Experimental verification of the asymtotic modal analysis method as applied to a rectangular acoustic cavity excited by structural vibration (United States)

    Peretti, L. F.; Dowell, E. H.


    An experiment was performed on a rigid wall rectangular acoustic cavity driven by a flexible plate mounted in a quarter of one end wall and excited by white noise. The experiment was designed so that the assumptions of Asymptotic Modal Analysis (AMA) were satisfied for certain bandwidths and center frequencies. Measurements of sound pressure levels at points along the boundaries and incrementally into tbe interior were taken. These were compared with the theoretical results predicted with AMA, and found to be in good agreement, particularly for moderate (1/3 octave) bandwidths and sufficiently high center frequencies. Sound pressure level measurements were also taken well into the cavity interior at various points along the 5 totally rigid walls. The AMA theory, including boundary intensification effects, was shown to be accurate provided the assumption of large number of acoustic modes is satisfied, and variables such as power spectra of the wall acceleration, frequency, and damping are slowly varying in the frequency of bandwidth.

  13. Modification of exhaust muffler of a diesel engine based on finite element method acoustic analysis

    Directory of Open Access Journals (Sweden)

    Jun Fu


    Full Text Available In order to improve the acoustic attenuation performance of an exhaust muffler of a 175 series of agricultural diesel engine, automatic matched layer method of finite element is adopted on the basis of LMS Virtual.Lab software to simulate the non-reflecting boundary conditions, which can avoid the complex calculation and then figure out the value of propagated sound power directly and finally obtain the transmission loss of the exhaust muffler. Compared with the experimental data, it can be found that the error between the simulation and measured values is small, and it can be accurately simulated for the acoustic performance of the exhaust muffler at the frequencies smaller than 3000 Hz, which verifies the validity of the acoustic solution. An improved design that properly distributes the insertion length of intubation, increases the length–diameter ratio, and adds the length of the first expansion cavity is proposed for the poor acoustic attenuation performance in low and medium frequencies. Compared with the original design, the transmission loss value at low and medium frequencies obviously increases, so the acoustic attenuation performance at the frequencies becomes better.

  14. Preliminary study of acoustic analysis for evaluating speech-aid oral prostheses: Characteristic dips in octave spectrum for comparison of nasality. (United States)

    Chang, Yen-Liang; Hung, Chao-Ho; Chen, Po-Yueh; Chen, Wei-Chang; Hung, Shih-Han


    Acoustic analysis is often used in speech evaluation but seldom for the evaluation of oral prostheses designed for reconstruction of surgical defect. This study aimed to introduce the application of acoustic analysis for patients with velopharyngeal insufficiency (VPI) due to oral surgery and rehabilitated with oral speech-aid prostheses. The pre- and postprosthetic rehabilitation acoustic features of sustained vowel sounds from two patients with VPI were analyzed and compared with the acoustic analysis software Praat. There were significant differences in the octave spectrum of sustained vowel speech sound between the pre- and postprosthetic rehabilitation. Acoustic measurements of sustained vowels for patients before and after prosthetic treatment showed no significant differences for all parameters of fundamental frequency, jitter, shimmer, noise-to-harmonics ratio, formant frequency, F1 bandwidth, and band energy difference. The decrease in objective nasality perceptions correlated very well with the decrease in dips of the spectra for the male patient with a higher speech bulb height. Acoustic analysis may be a potential technique for evaluating the functions of oral speech-aid prostheses, which eliminates dysfunctions due to the surgical defect and contributes to a high percentage of intelligible speech. Octave spectrum analysis may also be a valuable tool for detecting changes in nasality characteristics of the voice during prosthetic treatment of VPI. Copyright © 2014. Published by Elsevier B.V.

  15. Review of Progress in Acoustic Levitation (United States)

    Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.


    Acoustic levitation uses acoustic radiation forces to counteract gravity and suspend objects in mid-air. Although acoustic levitation was first demonstrated almost a century ago, for a long time, it was limited to objects much smaller than the acoustic wavelength levitating at fixed positions in space. Recent advances in acoustic levitation now allow not only suspending but also rotating and translating objects in three dimensions. Acoustic levitation is also no longer restricted to small objects and can now be employed to levitate objects larger than the acoustic wavelength. This article reviews the progress of acoustic levitation, focusing on the working mechanism of different types of acoustic levitation devices developed to date. We start with a brief review of the theory. Then, we review the acoustic levitation methods to suspend objects at fixed positions, followed by the techniques that allow the manipulation of objects. Finally, we present a brief summary and offer some future perspectives for acoustic levitation.

  16. Diagnostics of DC and Induction Motors Based on the Analysis of Acoustic Signals

    Directory of Open Access Journals (Sweden)

    Glowacz A.


    Full Text Available In this paper, a non-invasive method of early fault diagnostics of electric motors was proposed. This method uses acoustic signals generated by electric motors. Essential features were extracted from acoustic signals of motors. A plan of study of acoustic signals of electric motors was proposed. Researches were carried out for faultless induction motor, induction motor with one faulty rotor bar, induction motor with two faulty rotor bars and flawless Direct Current, and Direct Current motor with shorted rotor coils. Researches were carried out for methods of signal processing: log area ratio coefficients, Multiple signal classification, Nearest Neighbor classifier and the Bayes classifier. A pattern creation process was carried out using 40 samples of sound. In the identification process 130 five-second test samples were used. The proposed approach will also reduce the costs of maintenance and the number of faulty motors in the industry.

  17. Analysis of combustion instability in liquid propellant engines with or without acoustic cavities (United States)

    Oberg, C. L.; Kesselring, R. C.; Warner, C., III; Schuman, M. D.


    Analytical studies have been made of the relative combustion stability of various propellant combinations when used with hardware configurations representative of current design practices and with or without acoustic cavities. Two combustion instability models, a Priem-type model and a modification of the Northern Research and Engineering (NREC) instability model, were used to predict the variation in engine stability with changes in operating conditions, hardware characteristics or propellant combination, exclusive of acoustic cavity effects. The NREC model was developed for turbojet engines but is applicable to liquid propellant engines. A steady-state combustion model was used to predict the needed input for the instability models. In addition, preliminary development was completed on a new model to predict the influence of an acoustic cavity with specific allowance for the effects the nozzle, steady flow and combustion.

  18. Acoustic signal characteristics of laser induced cavitation in DDFP droplet: Spectrum and time-frequency analysis. (United States)

    Feng, Yi; Qin, Dui; Zhang, Jun; Ma, Chenxiang; Wan, Mingxi


    Cavitation has great application potential in microvessel damage and targeted drug delivery. Concerning cavitation, droplet vaporization has been widely investigated in vitro and in vivo with plasmonic nanoparticles. Droplets with a liquid dodecafluoropentane (DDFP) core enclosed in an albumin shell have a stable and simple structure with good characteristics of laser absorbing; thus, DDFP droplets could be an effective aim for laser-induced cavitation. The DDPF droplet was prepared and perfused in a mimic microvessel in the optical microscopic system with a passive acoustic detection module. Three patterns of laser-induced cavitation in the droplets were observed. The emitted acoustic signals showed specific spectrum components at specific time points. It was suggested that a nanosecond laser pulse could induce cavitation in DDPF droplets, and specific acoustic signals would be emitted. Analyzing its characteristics could aid in monitoring the laser-induced cavitation process in droplets, which is meaningful to theranostic application.

  19. Finite element analysis of surface acoustic waves in high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim


    This paper elaborates on how the finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with optical waves in a waveguide. With a periodic model it is shown that these electrodes act as a mechanical resonator which slows...... down the SAWvelocity because of mechanical energy storage. A finite model is furthermore employed to study the acousto-optical interaction and shows that it is possible to get a bigger change in effective refractive index with these surface acoustic waves compared to using conventional interdigital...

  20. Gamma knife radiosurgery for acoustic neurinomas. Pt. 1. The analysis of tumor control

    Energy Technology Data Exchange (ETDEWEB)

    Fukuoka, Seiji; Seo, Yoshinobu; Nakagawara, Jyoji [Nakamura Memorial Hospital, Sapporo (Japan)] [and others


    Forty-three patients with the unilateral type of acoustic neurinoma who were treated with gamma knife radiosurgery were analyzed from the viewpoint of tumor control. The follow-up period ranged from 22 to 55 months. The tumors were treated with marginal radiation doses of 9-15 Gy with multiple isocenters. The actuarial tumor reduction rates were 42% at one year, 75% at 2 years, and 92% at 3 years after gamma knife radiosurgery. Transient tumor expansion was seen in 33% of patients, which correlated with previous surgical cases. The present control rate was 91%. SPECT was performed on 15 selected patients before and 1 year and 2 years after gamma knife radiosurgery. {sup 201}TlCl SPECT was used to determine tumor viability, and the early and delayed {sup 99m}Tc-DTPA-HSA-D SPECT images were used to assess tumor vascularity and permeability, respectively. The Tl index and HSA-D index of the delayed images were not significantly different from the respective preoperative values. However, there was a statistically significant decrease in the HSA-D index of the early images 1 year after treatment. A statistically significant reduction in tumor volume was seen 2 years after treatment in these 15 patients, meaning that a reduction in tumor vascularity was followed by a reduction in tumor size. One patient underwent surgical excision of the tumor 18 months after gamma knife radiosurgery because the tumor had expanded and resulted in cerebellar ataxia. Histopathologic investigation revealed the presence of some tumor cells with irregularly shaped nuclei and marked intimal thickening or obliteration of the tumor vessels. (K.H.)

  1. Empirical Mode Decomposition Analysis of Continuous Acoustic Emission (AE) Data from Laboratory Rock Deformation Experiments (United States)

    Flynn, J. W.; Goodfellow, S. D.; Nasseri, M. H. B.; Reyes-Montes, J. M.; Young, R. P.


    Continuous acoustic emission (AE) data recorded during rock deformation tests facilitates the monitoring of fracture initiation and propagation due to applied stress changes. Changes in the frequency and energy content of AE waveforms have been previously observed associated with microcrack coalescence and the induction or mobilisation of large fractures which are naturally associated with larger amplitude AE events and lower frequency components. The shift from high to low dominant frequency components during the late stages of the deformation experiment, as the rate of AE events increases and the sample approaches failure, indicates a transition from the micro-cracking to macro-cracking regime, where large cracks generated result in material failure. To analyse and characterise these changes, a detailed time-frequency analysis of the continuous waveform data is required. Fourier-based techniques (e.g. STFT) and the Wavelet Transform have several drawbacks such as fixed window size (STFT), poor time-frequency resolution and some general assumption of linearity and/or stationarity. These techniques are not suitable for the detailed analysis of AE data which are generally nonstationary and nonlinear. The Empirical Mode Decomposition (EMD) method is suitable for non-stationary and non-linear time-series analysis, with the ability to identify intrinsic features in the data. EMD adaptively decomposes a time-varying signal into a finite set of functions called intrinsic mode functions (IMFs), where each IMF represents an oscillatory term in the original signal in a different frequency band. The instantaneous frequency and amplitude of each IMF is derived by applying the Hilbert Transform (HT) to the IMFs which provides a high resolution time-frequency distribution of the data. This paper proposes the use of the combined EMD and HT method to analyse the continuous AE data recorded during a laboratory triaxial deformation experiment on a cylindrical sample of Westerly

  2. Analysis and experimental study on the effect of a resonant tube on the performance of acoustic levitation devices


    Hai Jiang; Jianfang Liu; Qingqing Lv; Shoudong Gu; Xiaoyang Jiao; Minjiao Li; Shasha Zhang


    The influence of a resonant tube on the performance of acoustic standing wave-based levitation device (acoustic levitation device hereinafter) is studied by analyzing the acoustic pressure and levitation force of four types of acoustic levitation devices without a resonance tube and with resonance tubes of different radii R using ANSYS and MATLAB. Introducing a resonance tube either enhances or weakens the levitation strength of acoustic levitation device, depending on the resonance tube radi...

  3. Acoustic Data Processing and Transient Signal Analysis for the Hybrid Wing Body 14- by 22-Foot Subsonic Wind Tunnel Test (United States)

    Bahr, Christopher J.; Brooks, Thomas F.; Humphreys, William M.; Spalt, Taylor B.; Stead, Daniel J.


    An advanced vehicle concept, the HWB N2A-EXTE aircraft design, was tested in NASA Langley's 14- by 22-Foot Subsonic Wind Tunnel to study its acoustic characteristics for var- ious propulsion system installation and airframe con gurations. A signi cant upgrade to existing data processing systems was implemented, with a focus on portability and a re- duction in turnaround time. These requirements were met by updating codes originally written for a cluster environment and transferring them to a local workstation while en- abling GPU computing. Post-test, additional processing of the time series was required to remove transient hydrodynamic gusts from some of the microphone time series. A novel automated procedure was developed to analyze and reject contaminated blocks of data, under the assumption that the desired acoustic signal of interest was a band-limited sta- tionary random process, and of lower variance than the hydrodynamic contamination. The procedure is shown to successfully identify and remove contaminated blocks of data and retain the desired acoustic signal. Additional corrections to the data, mainly background subtraction, shear layer refraction calculations, atmospheric attenuation and microphone directivity corrections, were all necessary for initial analysis and noise assessments. These were implemented for the post-processing of spectral data, and are shown to behave as expected.

  4. Particle manipulation by a non-resonant acoustic levitator

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marco A. B., E-mail: [Institute of Physics, University of São Paulo, CP 66318, 05314-970 São Paulo (Brazil); Pérez, Nicolás [Centro Universitario de Paysandú, Universidad de la República, Ruta 3 km 363, 60000 Paysandú (Uruguay); Adamowski, Julio C. [Department of Mechatronics and Mechanical Systems Engineering, Escola Politécnica, University of São Paulo, Av. Mello Moraes, 2231, 05508-030 São Paulo (Brazil)


    We present the analysis of a non-resonant acoustic levitator, formed by an ultrasonic transducer and a concave reflector. In contrast to traditional levitators, the geometry presented herein does not require the separation distance between the transducer and the reflector to be a multiple of half wavelength. The levitator behavior is numerically predicted by applying a numerical model to calculate the acoustic pressure distribution and the Gor'kov theory to obtain the potential of the acoustic radiation force that acts on a levitated particle. We also demonstrate that levitating particles can be manipulated by controlling the reflector position while maintaining the transducer in a fixed position.

  5. Present and foreseeable future of metabolomics in forensic analysis. (United States)

    Castillo-Peinado, L S; Luque de Castro, M D


    The revulsive publications during the last years on the precariousness of forensic sciences worldwide have promoted the move of major steps towards improvement of this science. One of the steps (viz. a higher involvement of metabolomics in the new era of forensic analysis) deserves to be discussed under different angles. Thus, the characteristics of metabolomics that make it a useful tool in forensic analysis, the aspects in which this omics is so far implicit, but not mentioned in forensic analyses, and how typical forensic parameters such as the post-mortem interval or fingerprints take benefits from metabolomics are critically discussed in this review. The way in which the metabolomics-forensic binomial succeeds when either conventional or less frequent samples are used is highlighted here. Finally, the pillars that should support future developments involving metabolomics and forensic analysis, and the research required for a fruitful in-depth involvement of metabolomics in forensic analysis are critically discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Acoustic Modeling and Analysis for the Space Shuttle Main Propulsion System Liner Crack Investigation (United States)

    Casiano, Matthew J.; Zoladz, Tom F.


    Cracks were found on bellows flow liners in the liquid hydrogen feedlines of several space shuttle orbiters in 2002. An effort to characterize the fluid environment upstream of the space shuttle main engine low-pressure fuel pump was undertaken to help identify the cause of the cracks and also provide quantitative environments and loads of the region. Part of this effort was to determine the duct acoustics several inches upstream of the low-pressure fuel pump in the region of a bellows joint. A finite element model of the complicated geometry was made using three-dimensional fluid elements. The model was used to describe acoustics in the complex geometry and played an important role in the investigation. Acoustic mode shapes and natural frequencies of the liquid hydrogen in the duct and in the cavity behind the flow liner were determined. Forced response results were generated also by applying an edgetone-like forcing to the liner slots. Studies were conducted for state conditions and also conditions assuming two-phase entrapment in the backing cavity. Highly instrumented single-engine hot fire data confirms the presence of some of the predicted acoustic modes.

  7. Perturbation and Nonlinear Dynamic Analysis of Acoustic Phonatory Signal in Parkinsonian Patients Receiving Deep Brain Stimulation (United States)

    Lee, Victoria S.; Zhou, Xiao Ping; Rahn, Douglas A., III; Wang, Emily Q.; Jiang, Jack J.


    Nineteen PD patients who received deep brain stimulation (DBS), 10 non-surgical (control) PD patients, and 11 non-pathologic age- and gender-matched subjects performed sustained vowel phonations. The following acoustic measures were obtained on the sustained vowel phonations: correlation dimension (D[subscript 2]), percent jitter, percent shimmer,…

  8. Crack propagation analysis using acoustic emission sensors for structural health monitoring systems. (United States)

    Kral, Zachary; Horn, Walter; Steck, James


    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN). Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems.

  9. Articulatory-to-Acoustic Relations in Talkers with Dysarthria: A First Analysis (United States)

    Mefferd, Antje


    Purpose: The primary purpose of this study was to determine the strength of interspeaker and intraspeaker articulatory-to-acoustic relations of vowel contrast produced by talkers with dysarthria and controls. Methods: Six talkers with amyotrophic lateral sclerosis (ALS), six talkers with Parkinson's disease (PD), and 12 controls repeated a…

  10. Analysis tools for the design of active structural acoustic control systems.

    NARCIS (Netherlands)

    Oude nijhuis, M.H.H.


    Acoustic noise is an important problem in the modern society and provides much of the impetus for the development of noise reduction techniques. Passive methods, such as the use of sound absorbing materials, provide an adequate solution to many noise problems, but for noise reduction at low

  11. Big data extraction with adaptive wavelet analysis (Presentation Video) (United States)

    Qu, Hongya; Chen, Genda; Ni, Yiqing


    Nondestructive evaluation and sensing technology have been increasingly applied to characterize material properties and detect local damage in structures. More often than not, they generate images or data strings that are difficult to see any physical features without novel data extraction techniques. In the literature, popular data analysis techniques include Short-time Fourier Transform, Wavelet Transform, and Hilbert Transform for time efficiency and adaptive recognition. In this study, a new data analysis technique is proposed and developed by introducing an adaptive central frequency of the continuous Morlet wavelet transform so that both high frequency and time resolution can be maintained in a time-frequency window of interest. The new analysis technique is referred to as Adaptive Wavelet Analysis (AWA). This paper will be organized in several sections. In the first section, finite time-frequency resolution limitations in the traditional wavelet transform are introduced. Such limitations would greatly distort the transformed signals with a significant frequency variation with time. In the second section, Short Time Wavelet Transform (STWT), similar to Short Time Fourier Transform (STFT), is defined and developed to overcome such shortcoming of the traditional wavelet transform. In the third section, by utilizing the STWT and a time-variant central frequency of the Morlet wavelet, AWA can adapt the time-frequency resolution requirement to the signal variation over time. Finally, the advantage of the proposed AWA is demonstrated in Section 4 with a ground penetrating radar (GPR) image from a bridge deck, an analytical chirp signal with a large range sinusoidal frequency change over time, the train-induced acceleration responses of the Tsing-Ma Suspension Bridge in Hong Kong, China. The performance of the proposed AWA will be compared with the STFT and traditional wavelet transform.

  12. Low frequency acoustic properties of bilayer membrane acoustic metamaterial with magnetic oscillator

    Directory of Open Access Journals (Sweden)

    Nansha Gao


    Full Text Available A bilayer membrane acoustic metamaterial was proposed to overcome the influence of the mass law on traditional acoustic materials and obtain a lightweight thin-layer structure that can effectively isolate low frequency noise. The finite element analysis (FEA results agree well with the experimental results. It is proved that the sound transmission losses (STLs of the proposed structures are higher than those of same surface density acoustic materials. The introduction of the magnetic mass block is different from the traditional design method, in which only a passive mass block is fixed on the membrane. The magnetic force will cause tension in the membrane, increase membrane prestress, and improve overall structural stiffness. The effects of the geometry size on the STLs are discussed in detail. The kind of method presented in this paper can provide a new means for engineering noise control. Keywords: Bilayer membrane acoustic metamaterial, Low frequency sound insulation, Sound transmission loss, Magnet oscillator

  13. Understanding acoustics an experimentalist’s view of acoustics and vibration

    CERN Document Server

    Garrett, Steven L


    This textbook provides a unified approach to acoustics and vibration suitable for use in advanced undergraduate and first-year graduate courses on vibration and fluids. The book includes thorough treatment of vibration of harmonic oscillators, coupled oscillators, isotropic elasticity, and waves in solids including the use of resonance techniques for determination of elastic moduli. Drawing on 35 years of experience teaching introductory graduate acoustics at the Naval Postgraduate School and Penn State, the author presents a hydrodynamic approach to the acoustics of sound in fluids that provides a uniform methodology for analysis of lumped-element systems and wave propagation that can incorporate attenuation mechanisms and complex media. This view provides a consistent and reliable approach that can be extended with confidence to more complex fluids and future applications. Understanding Acoustics opens with a mathematical introduction that includes graphing and statistical uncertainty, followed by five chap...

  14. Supersonic acoustic intensity with statistically optimized near-field acoustic holography

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn


    The concept of supersonic acoustic intensity was introduced some years ago for estimating the fraction of the flow of energy radiated by a source that propagates to the far field. It differs from the usual (active) intensity by excluding the near-field energy resulting from evanescent waves...... and circulating energy in the near-field of the source. This quantity is of concern because it makes it possible to identify the regions of a source that contribute to the far field radiation, which is often the ultimate concern in noise control. Therefore, this is a very useful analysis tool complementary...... to the information provided by the near-field acoustic holography technique. This study proposes a version of the supersonic acoustic intensity applied to statistically optimized near-field acoustic holography (SONAH). The theory, numerical results and an experimental study are presented. The possibility of using...

  15. Presenting the Straddle Lemma in an Introductory Real Analysis Course (United States)

    Soares, A.; dos Santos, A. L.


    In this article, we revisit the concept of strong differentiability of real functions of one variable, underlying the concept of differentiability. Our discussion is guided by the Straddle Lemma, which plays a key role in this context. The proofs of the results presented are designed to meet a young audience in mathematics, typical of students in…

  16. A prospective analysis of the presentation and management of ...

    African Journals Online (AJOL)

    The mean hospital stay was 3.7 days. The identified complications were erectile dysfunction (6.7%) and penile curvature (13.3%). Conclusion: Coitus is the commonest aetiological factor for fracture of the penis in our environment. Though the majority of the patient still present late, immediate surgical repair is associated ...

  17. Acute and intermittent testicular torsion: Analysis of presentation ...

    African Journals Online (AJOL)

    Background: Testicular torsion compromises the blood supply to the testes and may result in testicular loss or damage if not dealt with promptly. It can occur either as acute testicular torsion (ATT) or intermittent testicular torsion (ITT). This study examines the presentation, management, and outcome of adult testicular torsion.

  18. Acute and intermittent testicular torsion: Analysis of presentation ...

    African Journals Online (AJOL)


    Nov 18, 2015 ... Background: Testicular torsion compromises the blood supply to the testes and may result in testicular loss or damage if not dealt with promptly. It can occur either as acute testicular torsion (ATT) or intermittent testicular torsion (ITT). This study examines the presentation, management, and outcome of adult ...

  19. An Acoustic Analysis of the Genus Microhyla (Anura: Microhylidae) of Sri Lanka. (United States)

    Wijayathilaka, Nayana; Meegaskumbura, Madhava


    Vocalizing behavior of frogs and toads, once quantified, is useful for systematics, rapid species identification, behavioral experimentation and conservation monitoring. But yet, for many lineages vocalizations remain unknown or poorly quantified, especially in diversity rich tropical regions. Here we provide a quantitative acoustical analysis for all four Sri Lankan congeners of the genus Microhyla. Three of these species are endemic to the island, but Microhyla ornata is regionally widespread. Two of these endemics, M. karunaratnei (Critically Endangered) and M. zeylanica (Endangered), are highly threatened montane isolates; the other, M. mihintalei, is relatively common across the dry lowlands. We recorded and analyzed 100 advertisement calls from five calling males for each species, except for M. zeylanica, which only had 53 calls from three males suitable for analyses. All four species call in choruses and their vocal repertoires are simple compared to most frogs. Their calls contain multiple pulses and no frequency modulation. We quantified eight call characters. Call duration and number of pulses were higher for the two montane isolates (inhabiting cooler habitats at higher altitudes) compared to their lowland congeners. Microhyla zeylanica has the longest call duration (of 1.8 ± 0.12 s) and the highest number of pulses (of 61-92 pulses). The smallest of the species, Microhyla karunaratnei (16.2-18.3 mm), has the highest mean dominant frequency (3.3 ± 0.14 kHz) and pulse rate (77 ± 5.8 pulses per second). The calls separate well in the Principal Component space: PC1 axis is mostly explained by the number of pulses per call and call duration; PC2 is mostly explained by the pulse rate. A canonical means plot of a Discriminant Function analysis shows non-overlapping 95% confidence ellipses. This suggests that some call parameters can be used to distinguish these species effectively. We provide detailed descriptions for eight call properties and compare these

  20. An Acoustic Analysis of the Genus Microhyla (Anura: Microhylidae) of Sri Lanka (United States)

    Wijayathilaka, Nayana


    Vocalizing behavior of frogs and toads, once quantified, is useful for systematics, rapid species identification, behavioral experimentation and conservation monitoring. But yet, for many lineages vocalizations remain unknown or poorly quantified, especially in diversity rich tropical regions. Here we provide a quantitative acoustical analysis for all four Sri Lankan congeners of the genus Microhyla. Three of these species are endemic to the island, but Microhyla ornata is regionally widespread. Two of these endemics, M. karunaratnei (Critically Endangered) and M. zeylanica (Endangered), are highly threatened montane isolates; the other, M. mihintalei, is relatively common across the dry lowlands. We recorded and analyzed 100 advertisement calls from five calling males for each species, except for M. zeylanica, which only had 53 calls from three males suitable for analyses. All four species call in choruses and their vocal repertoires are simple compared to most frogs. Their calls contain multiple pulses and no frequency modulation. We quantified eight call characters. Call duration and number of pulses were higher for the two montane isolates (inhabiting cooler habitats at higher altitudes) compared to their lowland congeners. Microhyla zeylanica has the longest call duration (of 1.8 ± 0.12 s) and the highest number of pulses (of 61–92 pulses). The smallest of the species, Microhyla karunaratnei (16.2–18.3 mm), has the highest mean dominant frequency (3.3 ± 0.14 kHz) and pulse rate (77 ± 5.8 pulses per second). The calls separate well in the Principal Component space: PC1 axis is mostly explained by the number of pulses per call and call duration; PC2 is mostly explained by the pulse rate. A canonical means plot of a Discriminant Function analysis shows non-overlapping 95% confidence ellipses. This suggests that some call parameters can be used to distinguish these species effectively. We provide detailed descriptions for eight call properties and compare

  1. Modeling, design, packing and experimental analysis of liquid-phase shear-horizontal surface acoustic wave sensors (United States)

    Pollard, Thomas B

    Recent advances in microbiology, computational capabilities, and microelectromechanical-system fabrication techniques permit modeling, design, and fabrication of low-cost, miniature, sensitive and selective liquid-phase sensors and lab-on-a-chip systems. Such devices are expected to replace expensive, time-consuming, and bulky laboratory-based testing equipment. Potential applications for devices include: fluid characterization for material science and industry; chemical analysis in medicine and pharmacology; study of biological processes; food analysis; chemical kinetics analysis; and environmental monitoring. When combined with liquid-phase packaging, sensors based on surface-acoustic-wave (SAW) technology are considered strong candidates. For this reason such devices are focused on in this work; emphasis placed on device modeling and packaging for liquid-phase operation. Regarding modeling, topics considered include mode excitation efficiency of transducers; mode sensitivity based on guiding structure materials/geometries; and use of new piezoelectric materials. On packaging, topics considered include package interfacing with SAW devices, and minimization of packaging effects on device performance. In this work novel numerical models are theoretically developed and implemented to study propagation and transduction characteristics of sensor designs using wave/constitutive equations, Green's functions, and boundary/finite element methods. Using developed simulation tools that consider finite-thickness of all device electrodes, transduction efficiency for SAW transducers with neighboring uniform or periodic guiding electrodes is reported for the first time. Results indicate finite electrode thickness strongly affects efficiency. Using dense electrodes, efficiency is shown to approach 92% and 100% for uniform and periodic electrode guiding, respectively; yielding improved sensor detection limits. A numerical sensitivity analysis is presented targeting viscosity

  2. Mueller matrix polarimetry imaging for breast cancer analysis (Conference Presentation) (United States)

    Gribble, Adam; Vitkin, Alex


    Polarized light has many applications in biomedical imaging. The interaction of a biological sample with polarized light reveals information about its biological composition, both structural and functional. The most comprehensive type of polarimetry analysis is to measure the Mueller matrix, a polarization transfer function that completely describes how a sample interacts with polarized light. However, determination of the Mueller matrix requires tissue analysis under many different states of polarized light; a time consuming and measurement intensive process. Here we address this limitation with a new rapid polarimetry system, and use this polarimetry platform to investigate a variety of tissue changes associated with breast cancer. We have recently developed a rapid polarimetry imaging platform based on four photoelastic modulators (PEMs). The PEMs generate fast polarization modulations that allow the complete sample Mueller matrix to be imaged over a large field of view, with no moving parts. This polarimetry system is then demonstrated to be sensitive to a variety of tissue changes that are relevant to breast cancer. Specifically, we show that changes in depolarization can reveal tumor margins, and can differentiate between viable and necrotic breast cancer metastasized to the lymph nodes. Furthermore, the polarimetric property of linear retardance (related to birefringence) is dependent on collagen organization in the extracellular matrix. These findings indicate that our polarimetry platform may have future applications in fields such as breast cancer diagnosis, improving the speed and efficacy of intraoperative pathology, and providing prognostic information that may be beneficial for guiding treatment.

  3. Acoustical Imaging

    CERN Document Server

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


    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

  4. Acoustic assessment of erygmophonic speech of Moroccan ...

    African Journals Online (AJOL)

    Introduction: Acoustic evaluation of alaryngeal voices is among the most prominent issues in speech analysis field. In fact, many methods have been developed to date to substitute the classic perceptual evaluation. The Aim of this study is to present our experience in erygmophonic speech objective assessment and to ...

  5. Acoustic Evidence for Phonologically Mismatched Speech Errors (United States)

    Gormley, Andrea


    Speech errors are generally said to accommodate to their new phonological context. This accommodation has been validated by several transcription studies. The transcription methodology is not the best choice for detecting errors at this level, however, as this type of error can be difficult to perceive. This paper presents an acoustic analysis of…

  6. Phonation Types in Marathi: An Acoustic Investigation (United States)

    Berkson, Kelly Harper


    This dissertation presents a comprehensive instrumental acoustic analysis of phonation type distinctions in Marathi, an Indic language with numerous breathy voiced sonorants and obstruents. Important new facts about breathy voiced sonorants, which are crosslinguistically rare, are established: male and female speakers cue breathy phonation in…

  7. Acoustic textiles

    CERN Document Server

    Nayak, Rajkishore


    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.

  8. Surface analysis of chalcogenide semiconductors used in photovoltaics (Conference Presentation) (United States)

    Rockett, Angus A.


    Both CdTe and Cu(In,Ga)Se2 have produced highly efficient thin film solar cells, exceeding 22% in champion devices. Both are also manufactured in large scales and show promise as future energy technologies. However, understanding the current collection mechanisms and mechanisms of instability in the devices remain a concern. To address these questions, we have used scanning probe and photoemission spectroscopies to study the response of chalcogenide materials to light and how charge is collected. Results of scanning microwave impedance microscopy and conductive atomic force microscopy show dramatic differences in the behavior of CdTe and Cu(In,Ga)Se2 (CIGS). The results include characterization of the effect of CdCl2 treatment on the properties CdTe grains and grain boundaries. This treatment dramatically increases the current collection in the grain boundaries. Thus we show that CdTe solar cells operate apparently by generation of electron hole pairs in the CdTe grains and collection of electrons to the grain boundaries. By contrast, CIGS grains show little or no contrast between the grains and grain boundaries and no obvious conduction pathway through the grain boundaries appears to exist. Our surface analysis results are supplemented with other measurements of both surface and bulk microchemistry and microstructure.

  9. Nonlocal resonances in nanoplasmonics: analysis and simulations (Conference Presentation) (United States)

    Burda, Milan; Kwiecien, Pavel; Fiala, Jan; Richter, Ivan


    developed the extension of the rigorous coupled wave analysis technique capable of treating nonlocal response numerically, for more general structures.

  10. Performance analysis of different adapative algorithms based on acoustic echo cancellation


    Adapa, Nagaswaroopa; Bollu, Sravya


    In modern telecommunication systems like hands-free and teleconferencing systems, the problem arise during conversation is the creation of an acoustic echo. This problem degrades the quality of the information signal. All speech processing equipments like noise cancelling headphones and hearing aids should be able to filter different kinds of interfering signals and produce a clear sound to the listener. Currently, echo cancellation is a most interesting and challenging task in any communicat...

  11. Acoustical Emission Analysis by Unsupervised Graph Mining: A Novel Biomarker of Knee Health Status. (United States)

    Hersek, Sinan; Pouyan, Maziyar Baran; Teague, Caitlin N; Sawka, Michael N; Millard-Stafford, Mindy L; Kogler, Geza F; Wolkoff, Paul; Inan, Omer T


    To study knee acoustical emission patterns in subjects with acute knee injury immediately following injury and several months after surgery and rehabilitation. We employed an unsupervised graph mining algorithm to visualize heterogeneity of the high-dimensional acoustical emission data, and to then derive a quantitative metric capturing this heterogeneity - the graph community factor (GCF). A total of 42 subjects participated in the studies. Measurements were taken once each from 33 healthy subjects with no known previous knee injury, and twice each from 9 subjects with unilateral knee injury: first, within seven days of the injury, and second, 4-6 months after surgery when the subjects were determined ready to start functional activities. Acoustical signals were processed to extract time and frequency domain features from multiple time windows of the recordings from both knees, and k-Nearest Neighbor graphs were then constructed based on these features. The GCF calculated from these graphs was found to be 18.5 ± 3.5 for healthy subjects, 24.8 ± 4.4 (p=0.01) for recently injured and 16.5 ± 4.7 (p=0.01) at 4-6 months recovery from surgery. The objective GCF scores changes were consistent with a medical professional's subjective evaluations and subjective functional scores of knee recovery. Unsupervised graph mining to extract GCF from knee acoustical emissions provides a novel objective and quantitative biomarker of knee injury and recovery that can be incorporated with a wearable joint health system for use outside of clinical settings, and austere / under resourced conditions, to aid treatment / therapy.

  12. Analysis of ray trajectories of flexural waves propagating over generalized acoustic black hole indentations (United States)

    Huang, Wei; Ji, Hongli; Qiu, Jinhao; Cheng, Li


    An Acoustic Black Hole (ABH) indentation embedded in thin-walled structures has been proved remarkably useful for broadband flexural wave focalization, in which the phase velocity of the flexural waves and the refractive index of the media undergo gradual changes from the outside towards the center of the indentation. A generalized two-dimensional ABH indentation can be defined by three geometric parameters: a power index, an extra thickness and a radius of a plateau at the indentation center. The dependence of the energy focalization on these parameters as well as the energy focalization process is of paramount importance for the understanding and design of effective ABH indentations. This work aims at investigating the energy focalization characteristics of flexural waves in such generalized ABH indentations. The calculation of the flexural ray trajectories is conducted to reveal and analyze the wave propagation features through numerical integration of the eikonal equation from the Geometric Acoustics Approximation (GAA). The theoretical results are verified by both experiment using wave visualization technique based on laser acoustic scanning method and finite element (FE) simulations. Finally, the influence of the geometric parameters on the flexural wave focalization characteristics in ABH indentations is discussed in detail.

  13. Analysis of Flame Extinguishment and Height in Low Frequency Acoustically Excited Methane Jet Diffusion Flame (United States)

    Zong, Ruowen; Kang, Ruxue; Liu, Chen; Zhang, Zhiyang; Zhi, Youran


    The exploration of microgravity conditions in space is increasing and existing fire extinguishing technology is often inadequate for fire safety in this special environment. As a result, improving the efficiency of portable extinguishers is of growing importance. In this work, a visual study of the effects on methane jet diffusion flames by low frequency sound waves is conducted to assess the extinguishing ability of sound waves. With a small-scale sound wave extinguishing bench, the extinguishing ability of certain frequencies of sound waves are identified, and the response of the flame height is observed and analyzed. Results show that the flame structure changes with disturbance due to low frequency sound waves of 60-100 Hz, and quenches at effective frequencies in the range of 60-90 Hz. In this range, 60 Hz is considered to be the quick extinguishing frequency, while 70-90 Hz is the stable extinguishing frequency range. For a fixed frequency, the flame height decreases with sound pressure level (SPL). The flame height exhibits the greatest sensitivity to the 60 Hz acoustic waves, and the least to the 100 Hz acoustic waves. The flame height decreases almost identically with disturbance by 70-90 Hz acoustic waves.

  14. Performance analysis of passive time reversal communication technique for multipath interference in shallow sea acoustic channel (United States)

    Kida, Yukihiro; Shimura, Takuya; Deguchi, Mitsuyasu; Watanabe, Yoshitaka; Ochi, Hiroshi; Meguro, Koji


    In this study, the performance of passive time reversal (PTR) communication techniques in multipath rich underwater acoustic environments is investigated. It is recognized empirically and qualitatively that a large number of multipath arrivals could generally raise the demodulation result of PTR. However, the relationship between multipath and the demodulation result is hardly evaluated quantitatively. In this study, the efficiency of the PTR acoustic communication techniques for multipath interference cancelation was investigated quantitatively by applying a PTR-DFE (decision feed-back filter) scheme to a synthetic dataset of a horizontal underwater acoustic channel. Mainly, in this study, we focused on the relationship between the signal-to-interference ratio (SIR) of datasets and the output signal-to-noise ratio (OSNR) of demodulation results by a parametric study approach. As a result, a proportional relation between SIR and OSNR is confirmed in low-SNR datasets. It was also found that PTR has a performance limitation, that is OSNR converges to a typical value depending on the number of receivers. In conclusion, results indicate that PTR could utilize the multipath efficiently and also withstand the negative effects of multipath interference at a given limitation.

  15. Modeling of surface acoustic wave strain sensors using coupling-of-modes analysis. (United States)

    Mc Cormack, Brian; Geraghty, Dermot; O'Mahony, Margaret


    SAW devices may be configured as strain sensors, providing passive, wireless strain measurement in demanding conditions. A key consideration is the modeling of the sensors, enabling different device designs to be considered. This paper presents a simulation scheme using coupling-of-modes (COM) analysis which allows both the frequency response of a SAW strain sensor and its bias sensitivity to be evaluated. Example applications are presented to demonstrate the use of the model.

  16. Musical Acoustics (United States)

    Gough, Colin

    This chapter provides an introduction to the physical and psycho-acoustic principles underlying the production and perception of the sounds of musical instruments. The first section introduces generic aspects of musical acoustics and the perception of musical sounds, followed by separate sections on string, wind and percussion instruments.

  17. Acoustic telemetry.

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.


    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  18. 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...... chapters represent review articles covering the most relevant areas of the field. They are written with the goal of providing students with comprehensive introductions. Further they offer a supply of numerous references to the relevant literature. Besides its usefulness as a textbook, this will make...... 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...

  19. Vibro-acoustic modulation–based damage identification in a composite skin–stiffener structure

    NARCIS (Netherlands)

    Ooijevaar, T.H.; Rogge, M.D.; Loendersloot, Richard; Warnet, Laurent; Akkerman, Remko; Tinga, Tiedo


    Vibro-acoustic modulation–based damage identification relies on the modulation of a high-frequency carrier signal by an intenser low-frequency vibration signal due to damage-induced structural nonlinearities. A time domain analysis of the vibro-acoustic modulation phenomena was presented at multiple

  20. Acoustic signal typing for evaluation of voice quality in tracheoesophageal speech

    NARCIS (Netherlands)

    van As-Brooks, Corina J.; Koopmans-van Beinum, Florien J.; Pols, Louis C. W.; Hilgers, Frans J. M.


    Because of the aperiodicity of many tracheoesophageal voices, acoustic analysis of the tracheoesophageal voice is less straightforward than that of the normal voice. This study presents the development and testing of an acoustic signal typing system based on visual inspection of a narrow-band

  1. Frequency effects on the scale and behavior of acoustic streaming. (United States)

    Dentry, Michael B; Yeo, Leslie Y; Friend, James R


    Acoustic streaming underpins an exciting range of fluid manipulation phenomena of rapidly growing significance in microfluidics, where the streaming often assumes the form of a steady, laminar jet emanating from the device surface, driven by the attenuation of acoustic energy within the beam of sound propagating through the liquid. The frequencies used to drive such phenomena are often chosen ad hoc to accommodate fabrication and material issues. In this work, we seek a better understanding of the effects of sound frequency and power on acoustic streaming. We present and, using surface acoustic waves, experimentally verify a laminar jet model that is based on the turbulent jet model of Lighthill, which is appropriate for acoustic streaming seen at micro- to nanoscales, between 20 and 936 MHz and over a broad range of input power. Our model eliminates the critically problematic acoustic source singularity present in Lighthill's model, replacing it with a finite emission area and enabling determination of the streaming velocity close to the source. At high acoustic power P (and hence high jet Reynolds numbers ReJ associated with fast streaming), the laminar jet model predicts a one-half power dependence (U∼P1/2∼ ReJ) similar to the turbulent jet model. However, the laminar model may also be applied to jets produced at low powers-and hence low jet Reynolds numbers ReJ-where a linear relationship between the beam power and streaming velocity exists: U∼P∼ReJ2. The ability of the laminar jet model to predict the acoustic streaming behavior across a broad range of frequencies and power provides a useful tool in the analysis of microfluidics devices, explaining peculiar observations made by several researchers in the literature. In particular, by elucidating the effects of frequency on the scale of acoustically driven flows, we show that the choice of frequency is a vitally important consideration in the design of small-scale devices employing acoustic streaming

  2. Damage analysis of CFRP-confined circular concrete-filled steel tubular columns by acoustic emission techniques (United States)

    Li, Dongsheng; Chen, Zhi; Feng, Quanming; Wang, Yanlei


    Damage properties of carbon fiber-reinforced polymer (CFRP) confined circular concrete-filled steel tubular (CCFT) columns were analyzed through acoustic emission (AE) signals. AE characteristic parameters were obtained through axial compression tests. The severity of damage to CFRP-CCFT columns was estimated using the growing trend of AE accumulated energy as basis. The bearing capacity of CFRP-CCFT columns and AE accumulated energy improved as CFRP layers increased. The damage process was studied using a number of crucial AE parameters. The cracks’ mode can be differentiated through the ratio of the rise time to the waveform amplitude and through average frequency analysis. With the use of intensity signal analysis, the damage process of the CFRP-CCFT columns can be classified into three levels that represent different degrees. Based on b-value analysis, the development of the obtained cracks can be defined. Thus, identifying an initial yielding and providing early warning is possible.

  3. Acoustic imaging system (United States)

    Smith, Richard W.


    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.

  4. Modeling fish egg production and spatial distribution from acoustic data: a step forward into the analysis of recruitment.

    Directory of Open Access Journals (Sweden)

    Andrés Ospina-Álvarez

    Full Text Available To date, there are numerous transport simulation studies demonstrating the relevance of the hydrodynamics for the advection, dispersion and recruitment of early stages of marine organisms. However, the lack of data has conditioned the use of realistic locations for the model setup and configuration in transport studies. This work (I demonstrates the key role played by the use of the realistic initial position of the eggs of small pelagic fishes in the analysis of late-larval recruitment in coastal nursery areas and (II provides a general solution for deriving future egg positions and abundances from adult biomass obtained from acoustic surveys and available fecundity data. Using European anchovy in the NW Mediterranean as a case study, we first analyzed the impact of the initial location, timing, egg buoyancy and diel vertical migration of larvae on the potential late-larval recruitment to coastal areas. The results suggested that prior knowledge of the initial spawning grounds may substantially affect the estimates of potential recruitment. We then integrated biological and acoustics-derived data (the biomass and size structure, sex ratio, a weight-batch fecundity model, mean weight, number of fish and mean spawning to build a predictive model for interannual egg production. This model was satisfactorily contrasted with field data for two years obtained with the Daily Egg Production Method (DEPM. We discuss our results in the context of the fluctuations of European anchovy egg abundance from 2003 through 2010 in the NW Mediterranean and in terms of the potential applicability of the acoustics-based spatial predictive egg production model.

  5. Preliminary study of acoustic analysis for evaluating speech-aid oral prostheses: Characteristic dips in octave spectrum for comparison of nasality

    Directory of Open Access Journals (Sweden)

    Yen-Liang Chang


    Conclusion: Acoustic analysis may be a potential technique for evaluating the functions of oral speech-aid prostheses, which eliminates dysfunctions due to the surgical defect and contributes to a high percentage of intelligible speech. Octave spectrum analysis may also be a valuable tool for detecting changes in nasality characteristics of the voice during prosthetic treatment of VPI.

  6. Surdez súbita unilateral como manifestação de schwannoma vestibular: relato de caso Sudden deafness as a presenting symptom of acoustic neuroma: case report

    Directory of Open Access Journals (Sweden)

    Sérgio Marquez Nascentes


    Full Text Available O schwannoma vestibular, também conhecido como neuroma ou neurinoma do acústico, é o tumor mais freqüente do ângulo pontocerebelar correspondendo a aproximadamente a 9% de todos os tumores intracranianos. APRESENTAÇÃO DO CASO: Os autores apresentam um relato de caso de surdez súbita e zumbido unilateral com melhora dos sintomas através de tratamento clínico com Prednisona e Pentoxifilina e posterior diagnóstico por exame de imagem de schwannoma vestibular. DISCUSSÃO: A surdez súbita pode ser descrita como uma perda neurossensorial abrupta e intensa. Costuma ser acima de 30 dB, em três ou mais freqüências contíguas e se desenvolve em menos de três dias. CONCLUSÃO: É de grande importância a pesquisa da etiologia nos casos de surdez súbita para a boa condução do caso e orientação terapêutica.Vestibular schwannoma, also known as acoustic neurinoma, is the most frequent tumor of the cerebellopontine angle, and represents 9% of all intracranial tumors. CASE REPORT: The authors report a case of sudden deafness with unilateral tinnitus. The patients responded to therapy with Prednisone and Pentoxifylline after the diagnosis of acoustic neurinoma by imaging exams. DISCUSSION: Sudden deafness can be described as an intense and abrupt sensorineural loss. Usually it is higher than 30 dB at three or more frequencies and develops in less than three days. CONCLUSION: Investigation of the etiology of sudden deafness is extremely important to establish the adequate strategy for the case.

  7. Hydrodynamic and acoustic analysis in 3-D of a section of main steam line to EPU conditions; Analisis hidrodinamico y acustico en 3D de una seccion de linea de vapor principal a condiciones de EPU

    Energy Technology Data Exchange (ETDEWEB)

    Centeno P, J.; Castillo J, V.; Espinosa P, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Area de Ingenieria en Recursos Energeticos, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Nunez C, A.; Polo L, M. A., E-mail: [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)


    The objective of this word is to study the hydrodynamic and acoustic phenomenon in the main steam lines (MSLs). For this study was considered the specific case of a pipe section of the MSL, where is located the standpipe of the pressure and/or safety relief valve (SRV). In the SRV cavities originates a phenomenon known as whistling that generates a hydrodynamic disturbance of acoustic pressure waves with different tones depending of the reactor operation conditions. In the SRV cavities the propagation velocity of the wave can originate mechanical damage in the structure of the steam dryer and on free parts. The importance of studying this phenomenon resides in the safety of the integrity of the reactor pressure vessel. To dissipate the energy of the pressure wave, acoustic side branches (ASBs) are used on the standpipe of the SRVs. The ASBs are arrangements of compacted lattices similar to a porous medium, where the energy of the whistling phenomenon is dissipate and therefore the acoustic pressure load that impacts in particular to the steam dryers, and in general to the interns of the vessel, diminishes. For the analysis of the whistling phenomenon two three-dimensional (3-D) models were built, one hydrodynamic in stationary state and other acoustic for the harmonic times in transitory regimen, in which were applied techniques of Computational Fluid Dynamics. The study includes the reactor operation analysis under conditions of extended power up rate (EPU) with ASB and without ASB. The obtained results of the gauges simulated in the MSL without ASB and with ASB, show that tones with values of acoustic pressure are presented in frequency ranges between 160 and 200 Hz around 12 MPa and of 7 MPa, respectively. This attenuation of tones implies the decrease of the acoustic loads in the steam dryer and in the interns of the vessel that are designed to support pressures not more to 7.5 MPa approximately. With the above-mentioned is possible to protect the steam dryer

  8. Bayesian hindcast of acoustic transmission loss in the western Pacific Ocean (United States)

    Palmsten, Margaret; Paquin Fabre, J.


    A Bayesian network is developed to demonstrate the feasibility of using environmental acoustic feature vectors (EAFVs) to predict underwater acoustic transmission loss (TL) versus range at two locations for a single acoustic source depth and frequency. Features for the networks are chosen based on a sensitivity analysis. The final network design resulted in a well-trained network, with high skill, little gain error, and low bias. The capability presented here shows promise for expansion to a more generalized approach, which could be applied at varying locations, depths and frequencies to estimate acoustic performance over a highly variable oceanographic area in real-time or near-real-time.

  9. Audio segmentation using Flattened Local Trimmed Range for ecological acoustic space analysis

    Directory of Open Access Journals (Sweden)

    Giovany Vega


    Full Text Available The acoustic space in a given environment is filled with footprints arising from three processes: biophony, geophony and anthrophony. Bioacoustic research using passive acoustic sensors can result in thousands of recordings. An important component of processing these recordings is to automate signal detection. In this paper, we describe a new spectrogram-based approach for extracting individual audio events. Spectrogram-based audio event detection (AED relies on separating the spectrogram into background (i.e., noise and foreground (i.e., signal classes using a threshold such as a global threshold, a per-band threshold, or one given by a classifier. These methods are either too sensitive to noise, designed for an individual species, or require prior training data. Our goal is to develop an algorithm that is not sensitive to noise, does not need any prior training data and works with any type of audio event. To do this, we propose: (1 a spectrogram filtering method, the Flattened Local Trimmed Range (FLTR method, which models the spectrogram as a mixture of stationary and non-stationary energy processes and mitigates the effect of the stationary processes, and (2 an unsupervised algorithm that uses the filter to detect audio events. We measured the performance of the algorithm using a set of six thoroughly validated audio recordings and obtained a sensitivity of 94% and a positive predictive value of 89%. These sensitivity and positive predictive values are very high, given that the validated recordings are diverse and obtained from field conditions. The algorithm was then used to extract audio events in three datasets. Features of these audio events were plotted and showed the unique aspects of the three acoustic communities.

  10. Acoustic emission analysis of the stages of deformation of TRIP steel (United States)

    Penkin, A. G.; Terent'ev, V. F.; Roshchupkin, V. V.; Slizov, A. K.; Sirotinkin, V. P.


    The kinetics of damage accumulation and deformation martensite formation in cold-rolled austenitic-martensitic VNS9-Sh TRIP steel during static tension at room temperature is studied at various stages of plastic deformation and fracture by acoustic emission and X-ray diffraction. The threshold stresses that correspond to the beginning of dislocation motion and intense dislocation generation predominantly in surface layers are determined. Deformation martensite is shown to form after a yield plateau and its formation is most intensely at the stage of strain hardening.

  11. Performance analysis of approximate Affine Projection Algorithm in acoustic feedback cancellation. (United States)

    Nikjoo S, Mohammad; Seyedi, Amir; Tehrani, Arash Saber


    Acoustic feedback is an annoying problem in several audio applications and especially in hearing aids. Adaptive feedback cancellation techniques have attracted recent attention and show great promise in reducing the deleterious effects of feedback. In this paper, we investigated the performance of a class of adaptive feedback cancellation algorithms viz. the approximated Affine Projection Algorithms (APA). Mixed results were obtained with the natural speech and music data collected from five different commercial hearing aids in a variety of sub-oscillatory and oscillatory feedback conditions. The performance of the approximated APA was significantly better with music stimuli than natural speech stimuli.

  12. A finite element large deflection random response analysis of beams and plates subjected to acoustic loading (United States)

    Mei, Chuh; Chiang, C. K.


    A finite element formulation is presented for the analysis of beams and rectangular plates undergoing large deflections subjected to Gaussian white noise excitations. Single-mode response is assumed in the present formulation. Root-mean-square (RMS) maximum deflections for simply supported and clamped beams and plates at various sound spectrum levels are obtained and compared with solutions using the Fokker-Planck-Kolmogorov equation and the equivalent linearization methods. RMS maximum stains and equivalent linear frequencies are compared with the equivalent linearization results for assessment of the accuracy of the finite element method.

  13. Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

    Directory of Open Access Journals (Sweden)

    Touchard F.


    Full Text Available This paper proposes to develop an experimental program to characterize the type and the development of damage in composite with complex microstructure. A multi-scale analysis by acoustic emission has been developed and applied to hemp fibre woven fabrics/epoxy composite. The experimental program consists of tensile tests performed on single yarn, neat epoxy resin and composite materials to identify their AE amplitude signatures. A statistical analysis of AE amplitude signals has been realised and correlated with microscopic observations. Results have enabled to identify three types of damage in composites and their associated AE amplitudes: matrix cracking, interfacial debonding and reinforcement damage and fracture. Tracking of these damage mechanisms in hemp/epoxy composites has been performed to show the process of damage development in natural fibre reinforced composites.

  14. Status reports on the development and application of acoustic emission analysis. Proceedings; Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse. Beitraege

    Energy Technology Data Exchange (ETDEWEB)



    The colloquium lectures represent the wide range of applications in acoustic emission analysis and testing in the areas of damage development and damage mechanisms, testing of components, condition monitoring, development of new measuring systems and sensors as well as software development regarding locating methods and signal analysis. One focus of the colloquium is on current hardware and software developments for status monitoring by means of AE monitoring. One of the papers was separately analyzed for this database. [German] Die Vortraege des Kolloquiums repraesentieren das breite Spektrum der Anwendungen der Schallemissionsanalyse und -pruefung in den Bereichen der Schadensentwicklung und Schadensmechanismen, Pruefung von Bauteilen, Zustandsueberwachung, Entwicklung neuer Messsysteme und Sensoren sowie Softwareentwicklung bezueglich Ortungsverfahren und Signalanalyse. Ein Schwerpunkt des Kolloquiums betrifft aktuelle Hard- und Softwareentwicklungen zur Zustandsueberwachung durch AE-Monitoring.

  15. An Intelligent Sensor Array Distributed System for Vibration Analysis and Acoustic Noise Characterization of a Linear Switched Reluctance Actuator

    Directory of Open Access Journals (Sweden)

    Maria Calado


    Full Text Available This paper proposes a distributed system for analysis and monitoring (DSAM of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs. The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications.

  16. An intelligent sensor array distributed system for vibration analysis and acoustic noise characterization of a linear switched reluctance actuator. (United States)

    Salvado, José; Espírito-Santo, António; Calado, Maria


    This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications.

  17. Hydro-seismic-acoustical monitoring of submarine earthquakes preparation: observations and analysis

    Directory of Open Access Journals (Sweden)

    E. V. Sasorova


    Full Text Available The results of laboratory experiments on rock sample destruction and the observation data obtained from several series of the hydro-acoustic observations in which the researchers succeeded to register the signals in the critical stage of the earthquake (EQ preparation were compared. According to theoretical research (Alekseev et al., 2001 two distinct dilatant zones occur in the EQ preparation stage. The first one is located around the source and the second one represents the near-surface dilatant zone. Only high-frequency seismic-acoustic signals (SAS radiated from the near-surface dilatant zone do not attenuate completely on the passage through a solid medium. Parameters of the SAS such as the source depth under the ocean floor, frequency maximum and the signal power level were estimated. It was shown that the critical stage of the EQ preparation continues several tens hours and this process has a hierarchical nature. At first the micro-ruptures are formed over a large area. Then the high frequency radiation begins to decrease, the SAS emission area begins to shrink and the micro-earthquakes occur in the area surrounding the epicenter. The obtained results are in close agreement with the theoretical conception about the evolution of the SAS in the surface dilatant zone and with the results of laboratory experiments.

  18. Defect Location Analysis of Tank Bottom Based on Acoustic Emission with Different Location Algorithms

    Directory of Open Access Journals (Sweden)

    Wang He


    Full Text Available Acoustic emission technology used in the state testing of the tank bottom has become a new hot spot for researchers and designers. Two location algorithms, such as three-point locating method and multi-point locating method are applied in this paper using multi-channel acoustic emission system for detection of tank bottom. The location result of the broken lead calibration shows that a larger error will be produced for different algorithm. The effects of the arrangement form of sensors on locating corrosion defect have been analyzed through experiments with two algorithms. The typical arrangement form of sensors has been discussed to study the effects on corrosion-pitting location. The test results show that two algorithms both have the capacity of locating defects and multipoint positioning algorithm is more accurate. It is not clear that the sensors distribution forms affect corrosion-pitting location. But the circumferential distribution of sensors along the bottom is better to test the state of tank with the consideration of feasibility, accuracy and rationality of signal source region. It is of practical engineering significance.

  19. Comprehensive Analysis of Traveltime Data Collected Through GPS-Acoustic Observation of Seafloor Crustal Movements (United States)

    Honsho, Chie; Kido, Motoyuki


    We have developed a comprehensive inversion scheme to analyze traveltime data collected through GPS-acoustic observations on a campaign basis. Our method uses a quantity called the "nadir total delay" (NTD), which is analogous to the zenith total delay in Global Navigation Satellite Systems analyses, to represent the time variation of the sound speed. The observation equation using the NTD is an approximated formulation. We examine its applicable scope using numerical experiments and demonstrate that the approximation holds well enough in practice. Traveltime data from all our observation campaigns were utilized together for inversion calculation to determine the following: (1) the positions of individual precision acoustic transponders at the time of a particular reference campaign, (2) the displacement from these positions of a rigid array at the time of each campaign, and (3) the time variation of the NTD during each campaign. We applied this method to actual data to fix the array geometry more precisely. Also, we have made a first step in detecting vertical motions as well as horizontal motions, though further enhancement of the accuracy will be required. In performing linear regression of array displacements obtained from the inversion, their error covariance has a significant effect on the resulting velocities. When the covariance is taken into account, nearly the same velocities are obtained no matter what campaign is taken as reference in the inversion.

  20. Analysis of Channel Coding Performance in OFDM Technique for Underwater Acoustic Communication System

    Directory of Open Access Journals (Sweden)

    Machmud Roby Alhamidi


    Full Text Available One way to increase the performance of Orthogonal Frequency Division Multiplexing System (OFDM system is by adding a channel coding (error correction code in order to detect and correct errors that occur when sending data.At communication of acoustic underwater channel coding is required because of the characteristics of the channel bottom water is much different compared with the air channel and errors are likely to occur.In this research it was made simulation of acoustic underwater communication system with OFDM applied channel codingin which using Hamming code (7,4 and Hamming code (15,11 that is able to correct one error and detect two errors then BCH code capable to correct two errors for BCH (15,7 and correct 9 errors forBCH (127,64 and Reed Solomon code able to correct two errors for RS (15,11 and correct 8 errors for RS (31,15. Results of the study confirm the better performance when system usesOFDM with BCH Code (127.64 than other codes that are used, starting from 1 decibel (dB to 3 dB for the performance of BER as10 -3 on Additive Gaussian White Noise (AWGN channel while at the multipath channel, the performance of Bit Error Rate (BER got better result on 1 dB up to 8 dB for BER performance as10 -3. Keyword: Underwater, Orthogonal Frequency Division Multiplexing (OFDM, channel coding

  1. Analysis of Acoustic Access to the Prostate Through the Abdomen and Perineum for Extracorporeal Ablation (United States)

    Hall, Timothy L.; Hempel, Christopher R.; Sabb, Brian J.; Roberts, William W.


    As part of the development of a noninvasive treatment for BPH using histotripsy, this study aimed to measure acoustic access for extracorporeal ablation of the prostate. Both transabdominal and transperineal approaches were considered. The objective was to measure the size and shape of a transducer aperture that could target the prostate without obstruction. CT images obtained from 17 subjects >56 years of age were used to create 3D reconstructions of the lower abdomen and pelvis. Target locations on the urethra at the base, mid, and apex in the prostate were marked along with a transrectal imaging probe. Evenly space rays spanning were traced from each target location towards the perineum and separately towards the abdomen with the maximum x-ray density encountered along each path recorded. The overall free aperture through the perineum was found to be a triangular shaped region bounded by the lower bones of the pelvis and the transrectal probe varying significantly in size between subjects. The free aperture through the abdomen was wedge shaped limited by the pubis also with great subject to subject variability. Average unblocked fractions of an f/1 transducer to target base, veru, and apex through the perineum were 77.0%, 94.4%, and 99.6%, respectively. Averages targeting through the abdomen were 86.1%, 52.3%, and 11.0%. Acoustic access to the prostate for through the perineum was judged to be feasible.

  2. [Acoustic analysis for 21 patients with amyotrophic lateral sclerosis complaining of dysarthria]. (United States)

    Xie, Hua-shun; Ma, Fu-rong; Fan, Dong-sheng; Wang, Li-ping; Yan, Yan; Lu, Pei-quan


    To observe the characteristics of acoustic parameters of 21 patients with amyotrophic lateral sclerosis (ALS) complaining of dysarthria and to explore the possibility and clinical value of Multi-Dimensional Voice Program (MDVP) on aseessing the patient's voice. The clinical data and speech intelligibility of each of the 21 patients with ALS complaining of dysarthria were collected. All the 21 patients with ALS and 44 normal subjects were suggested to pronounce the vowel [a:]. The voice samples were collected and analyzed by Multi Dimensional Voice Program. The data were compared to detect the difference between the two groups. Speech intelligibility of 10 in the 21 patients was above 97% including 5 patients whose scores were 100%. It seemed that the speech intelligibility score was not related with the duration of the disease and the on-set part. The values of noise to harmonic ratio (NHR) of both the light and the severe damage to the speech group were higher than those of the control group with significant difference (Pdysarthria. There was more noise composition in the voice of the patients with dysarthria. NHR seemed to be the sensitive and stable parameter. Especially in patients whose speech intelligibility were affected severely, more acoustic parameters were detected with significant difference.

  3. An analysis of the acoustic cavitation noise spectrum: The role of periodic shock waves. (United States)

    Song, Jae Hee; Johansen, Kristoffer; Prentice, Paul


    Research on applications of acoustic cavitation is often reported in terms of the features within the spectrum of the emissions gathered during cavitation occurrence. There is, however, limited understanding as to the contribution of specific bubble activity to spectral features, beyond a binary interpretation of stable versus inertial cavitation. In this work, laser-nucleation is used to initiate cavitation within a few millimeters of the tip of a needle hydrophone, calibrated for magnitude and phase from 125 kHz to 20 MHz. The bubble activity, acoustically driven at f0 = 692 kHz, is resolved with high-speed shadowgraphic imaging at 5 × 10(6) frames per second. A synthetic spectrum is constructed from component signals based on the hydrophone data, deconvolved within the calibration bandwidth, in the time domain. Cross correlation coefficients between the experimental and synthetic spectra of 0.97 for the f0/2 and f0/3 regimes indicate that periodic shock waves and scattered driving field predominantly account for all spectral features, including the sub-harmonics and their over-harmonics, and harmonics of f0.

  4. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.


    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...

  5. Fundamentals of Shallow Water Acoustics

    CERN Document Server

    Katsnelson, Boris; Lynch, James


    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.

  6. High-Frequency Seafloor Acoustics

    CERN Document Server

    Jackson, Darrell R


    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.

  7. Observations and transport theory analysis of low frequency, acoustic mode propagation in the Eastern North Pacific Ocean. (United States)

    Chandrayadula, Tarun K; Colosi, John A; Worcester, Peter F; Dzieciuch, Matthew A; Mercer, James A; Andrew, Rex K; Howe, Bruce M


    Second order mode statistics as a function of range and source depth are presented from the Long Range Ocean Acoustic Propagation EXperiment (LOAPEX). During LOAPEX, low frequency broadband signals were transmitted from a ship-suspended source to a mode-resolving vertical line array. Over a one-month period, the ship occupied seven stations from 50 km to 3200 km distance from the receiver. At each station broadband transmissions were performed at a near-axial depth of 800 m and an off-axial depth of 350 m. Center frequencies at these two depths were 75 Hz and 68 Hz, respectively. Estimates of observed mean mode energy, cross mode coherence, and temporal coherence are compared with predictions from modal transport theory, utilizing the Garrett-Munk internal wave spectrum. In estimating the acoustic observables, there were challenges including low signal to noise ratio, corrections for source motion, and small sample sizes. The experimental observations agree with theoretical predictions within experimental uncertainty.

  8. Adaptive neuro-fuzzy inference system for acoustic analysis of 4-channel phonocardiograms using empirical mode decomposition. (United States)

    Becerra, Miguel A; Orrego, Diana A; Delgado-Trejos, Edilson


    The heart's mechanical activity can be appraised by auscultation recordings, taken from the 4-Standard Auscultation Areas (4-SAA), one for each cardiac valve, as there are invisible murmurs when a single area is examined. This paper presents an effective approach for cardiac murmur detection based on adaptive neuro-fuzzy inference systems (ANFIS) over acoustic representations derived from Empirical Mode Decomposition (EMD) and Hilbert-Huang Transform (HHT) of 4-channel phonocardiograms (4-PCG). The 4-PCG database belongs to the National University of Colombia. Mel-Frequency Cepstral Coefficients (MFCC) and statistical moments of HHT were estimated on the combination of different intrinsic mode functions (IMFs). A fuzzy-rough feature selection (FRFS) was applied in order to reduce complexity. An ANFIS network was implemented on the feature space, randomly initialized, adjusted using heuristic rules and trained using a hybrid learning algorithm made up by least squares and gradient descent. Global classification for 4-SAA was around 98.9% with satisfactory sensitivity and specificity, using a 50-fold cross-validation procedure (70/30 split). The representation capability of the EMD technique applied to 4-PCG and the neuro-fuzzy inference of acoustic features offered a high performance to detect cardiac murmurs.

  9. Circuit-field coupled finite element analysis method for an electromagnetic acoustic transducer under pulsed voltage excitation (United States)

    Hao, Kuan-Sheng; Huang, Song-Ling; Zhao, Wei; Wang, Shen


    This paper presents an analytical method for electromagnetic acoustic transducers (EMATs) under voltage excitation and considers the non-uniform distribution of the biased magnetic field. A complete model of EMATs including the non-uniform biased magnetic field, a pulsed eddy current field and the acoustic field is built up. The pulsed voltage excitation is transformed to the frequency domain by fast Fourier transformation (FFT). In terms of the time harmonic field equations of the EMAT system, the impedances of the coils under different frequencies are calculated according to the circuit-field coupling method and Poynting's theorem. Then the currents under different frequencies are calculated according to Ohm's law and the pulsed current excitation is obtained by inverse fast Fourier transformation (IFFT). Lastly, the sequentially coupled finite element method (FEM) is used to calculate the Lorentz force in the EMATs under the current excitation. An actual EMAT with a two-layer two-bundle printed circuit board (PCB) coil, a rectangular permanent magnet and an aluminium specimen is analysed. The coil impedances and the pulsed current are calculated and compared with the experimental results. Their agreement verified the validity of the proposed method. Furthermore, the influences of lift-off distances and the non-uniform static magnetic field on the Lorentz force under pulsed voltage excitation are studied.

  10. Sound isolation performance of interior acoustical sash (United States)

    Tocci, Gregory


    In existing, as well as new buildings, an interior light of glass mounted on the inside of a prime window is used to improve the sound transmission loss otherwise obtained by the prime window alone. Interior acoustical sash is most often 1/4 in. (6 mm) monolithic or laminated glass, and is typically spaced 3 in. to 6 in. from the glass of the prime window. This paper presents TL data measured at Riverbank Acoustical Laboratories by Solutia (formerly Monsanto) for lightweight prime windows of various types, with and without interior acoustical sash glazed with 1/4 in. laminated glass. The TL data are used to estimate the A-weighted insertion loss of interior acoustical sash when applied to prime windows glazed with lightweight glass for four transportation noise source types-highway traffic, aircraft, electric rail, and diesel rail. The analysis also has been extended to determine the insertion loss expressed as a change in OITC. The data also exhibit the reductions in insertion loss that can result from short-circuiting the interior acoustical sash with the prime window. [Work supported by Solutia, Inc.

  11. Acoustics Research (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....

  12. Room Acoustics (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.

  13. Acoustic Neuroma (United States)

    ... in June 1969 at Karolinska Hospital in Stockholm, Sweden. Since then, more than 10,000 acoustic neuroma ... of neurosurgeons, radiation oncologists, medical physicists and a nursing staff. Specialists in neuroimaging join the team when ...

  14. The Analyzing of Ultrasound Propagation Wawes through a Piezoelectric Transducer in Function of Acoustic Charge

    Directory of Open Access Journals (Sweden)

    Grigore Liviu Odobescu


    Full Text Available The nature of acoustic charge, which works with an electronic generator to generate high intensity ultra-acoustic field is very various in function of application used [2]. The values of elements from equivalent scheme may be to vary in time in function of technologic process [3]. This fact determines the variation of accord frequencies and value of acoustic charge. In this manner the efficiency can be modified in time if it no take measures to minimize these influences of complex impedance that works with electronic generator [4]. In this paper it is presented a method to analysis the influence of variation of acoustic charge and to minimize this influences for to assure an optimum operation of electronic generator, it is presented a program to calculate the power variation in function of acoustic charge and to chart the diagram of this variation. It is presented the experimental results obtained with the theory presented.

  15. Fractal analysis of acoustic emission parameter series of coal with different properties under uniaxial loading (United States)

    Yang, Huiming


    In order to study acoustic emission (AE) evolution characteristics of coal with different mechanical properties in failure process, uniaxial compression experiments of coals from 4 mines were carried out to analyse fractal feature of AE time series by G-P algorithm. The results indicate that AE parameter series of all 4 different coals have fractal feature, and the fractal dimension value of coal with different properties go through a process of “first rise, then fall”. The change of AE fractal dimension value can reflect the cracking evolution in coal failure process, which is closely related with the failure phase. The continuous decline of AE fractal dimension can be viewed as a precursor of impending failure of coal, which could provide theoretical basis for the AE pre-warning model establishment of coal dynamic disaster.

  16. Aerodynamic sound generation due to vortex-aerofoil interaction. Part 2: Analysis of the acoustic field (United States)

    Parasarathy, R.; Karamcheti, K.


    The Lighthill method was the basic procedure used to analyze the sound field associated with a vortex of modified strength interacting with an airfoil. A free vortex interacting with an airfoil in uniform motion was modeled in order to determine the sound field due to all the acoustic sources, not only on the airfoil surfaces (dipoles), but also the ones distributed on the perturbed flow field (quadrupoles) due to the vortex-airfoil interaction. Because inviscid flow is assumed in the study of the interaction, the quadrupoles considered in the perturbed flow field are entirely due to an unsteady flow field. The effects of airfoil thickness on the second radiation are examined by using a symmetric Joukowski airfoil for the vortex-airfoil interaction. Sound radiation in a plane, far field simplification, and computation of the sound field are discussed.

  17. Punch stretching process monitoring using acoustic emission signal analysis. II - Application of frequency domain deconvolution (United States)

    Liang, Steven Y.; Dornfeld, David A.; Nickerson, Jackson A.


    The coloring effect on the acoustic emission signal due to the frequency response of the data acquisition/processing instrumentation may bias the interpretation of AE signal characteristics. In this paper, a frequency domain deconvolution technique, which involves the identification of the instrumentation transfer functions and multiplication of the AE signal spectrum by the inverse of these system functions, has been carried out. In this way, the change in AE signal characteristics can be better interpreted as the result of the change in only the states of the process. Punch stretching process was used as an example to demonstrate the application of the technique. Results showed that, through the deconvolution, the frequency characteristics of AE signals generated during the stretching became more distinctive and can be more effectively used as tools for process monitoring.

  18. Acoustic lung signals analysis based on Mel frequency cepstral coefficients and self-organizing maps

    Directory of Open Access Journals (Sweden)

    Álvaro David Orjuela-Cañón


    Full Text Available This study analyzes acoustic lung signals with different abnormalities, using Mel Frequency Cepstral Coefficients (MFCC, Self-Organizing Maps (SOM, and K-means clustering algorithm. SOM models are known as artificial neural networks than can be trained in an unsupervised or supervised manner. Both approaches were used in this work to compare the utility of this tool in lung signals studies. Results showed that with a supervised training, the classification reached rates of 85 % in accuracy. Unsupervised training was used for clustering tasks, and three clusters was the most adequate number for both supervised and unsupervised training. In general, SOM models can be used in lung signals as a strategy to diagnose systems, finding number of clusters in data, and making classifications for computer-aided decision making systems.

  19. A use of regression analysis in acoustical diagnostics of gear drives (United States)

    Balitskiy, F. Y.; Genkin, M. D.; Ivanova, M. A.; Kobrinskiy, A. A.; Sokolova, A. G.


    A study is presented of components of the vibration spectrum as the filtered first and second harmonics of the tooth frequency which permits information to be obtained on the physical characteristics of the vibration excitation process, and an approach to be made to comparison of models of the gearing. Regression analysis of two random processes has shown a strong dependence of the second harmonic on the first, and independence of the first from the second. The nature of change in the regression line, with change in loading moment, gives rise to the idea of a variable phase shift between the first and second harmonics.

  20. Acoustic emission analysis of fiber-reinforced composite in flexural testing. (United States)

    Alander, Pasi; Lassila, Lippo V J; Tezvergil, Arzu; Vallittu, Pekka K


    The aim of this study was to examine the emission of acoustic signals from six commercially available fiber-reinforced composites (FRC) used in the frameworks of fixed partial dentures in material bending. FRC test specimens were made of six commercially available fiber products of polyethylene or glass and five light-curing resins. FRC test specimens were polymerized with a hand light-curing unit or with a light-curing oven. The flexural test for determination of ultimate flexural strength of test specimens (n = 6) was based on the ISO 10477 standard after the specimens were stored in air or in water for two weeks. The acoustic emission (AE) signals were monitored during three-point loading test of the test specimens using a test with increasing loading levels until the specimens fractured. Generally, stress level required for the AE activity initiation ranged from 107 MPa (Ribbond) to 579 MPa (everStick). The ultimate flexural strength of FRC specimens were higher, ranging from 132 to 764 MPa, being highest with everStick and Vectris FRC, and lowest with Ribbond FRC. ANOVA showed a statistically significant difference between the initiation of AE activity and the ultimate flexural strength according to the brand (p < 0.001) storing conditions (p < 0.001) and polymerization procedure (p < 0.001). AE activity and ultimate flexural strength correlated significantly (p < 0.010, r = 0.887). The result of this study suggested that AE activity in FRC specimens started at a 19-32% lower stress level than occurred at final fracture.

  1. Acoustic Neurinomas

    Directory of Open Access Journals (Sweden)

    Mohammad Faraji Rad


    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.

  2. A theoretical study of time-dependent, ultrasound-induced acoustic streaming in microchannels

    CERN Document Server

    Muller, Peter Barkholt


    Based on first- and second-order perturbation theory, we present a numerical study of the temporal build-up and decay of unsteady acoustic fields and acoustic streaming flows actuated by vibrating walls in the transverse cross-sectional plane of a long straight microchannel under adiabatic conditions and assuming temperature-independent material parameters. The unsteady streaming flow is obtained by averaging the time-dependent velocity field over one oscillation period, and as time increases, it is shown to converge towards the well-known steady time-averaged solution calculated in the frequency domain. Scaling analysis reveals that the acoustic resonance builds up much faster than the acoustic streaming, implying that the radiation force may dominate over the drag force from streaming even for small particles. However, our numerical time-dependent analysis indicates that pulsed actuation does not reduce streaming significantly due to its slow decay. Our analysis also shows that for an acoustic resonance wit...

  3. Speech rate and rhythm in cerebellar dysarthria: an acoustic analysis of syllabic timing. (United States)

    Ackermann, H; Hertrich, I


    Auditory-perceptual studies reported inconsistent data with respect to syllabic timing in cerebellar dysarthria, i.e. both reduced and increased variability of syllable durations. The present study performed a comprehensive analysis of syllabic timing during sentence utterances in 14 subjects with a pure cerebellar syndrome (CA). First, the CA patients presented with reduced speech tempo in terms of syllable and utterance durations. Second, a tendency for intrautterance syllabic isochrony, being an aspect of the percept of 'scanning speech', characterized a subgroup of patients with cerebellar dysarthria. Third, increased interutterance durational variability was found in three out of the five syllables considered. Thus, both reduced intrautterance and increased interutterance variability of syllable durations may pertain to cerebellar dysarthria. The latter dimension, however, seems to be more prominent.

  4. Análise acústica em brinquedos ruidosos Acoustics analysis of the noisy toys

    Directory of Open Access Journals (Sweden)

    Carla Linhares Taxini


    Inmetro and 10 without the seal with the use of digital sound level meter in an acoustically treated room, and the sound analysis was performed using the Praat program. RESULTS: toys placed at 2.5 cm from the equipment with the seal of the Inmetro had an intensity ranging from 61.50 to 91.55 dB (A and from 69.75 to 95.05 dB (C, positioned at 25 cm ranged from 58.3 to 79.85 dB (A and from 62.50 to 83.65 dB (C. The results of the toys without warranty stamps placed at 2.5 cm ranged from 67.45 to 94.30 dB (A and 65.4 to 99.50 dB (C and the distance of 25 cm recorded from 61. 30 to 87.45 dB (A and 63.75 to 97.60 dB (C, so that the findings demonstrated that there are noisy toys that go beyond the values recommended by the current legislation in both groups, with and without warranty stamps . CONCLUSION: the toys without the seal of Inmetro showed intensities values significantly higher than the other group, offering more risk to the children’s hearing health.

  5. The Acoustic Breathiness Index (ABI): A Multivariate Acoustic Model for Breathiness. (United States)

    Barsties V Latoszek, Ben; Maryn, Youri; Gerrits, Ellen; De Bodt, Marc


    The evaluation of voice quality is a major component of voice assessment. The aim of the present study was to develop a new multivariate acoustic model for the evaluation of breathiness. Concatenated voice samples of continuous speech and the sustained vowel [a:] from 970 subjects with dysphonia and 88 vocally healthy subjects were perceptually judged for breathiness severity. Acoustic analyses were conducted on the same concatenated voice samples after removal of the non-voiced segments of the continuous speech sample. The development of an acoustic model for breathiness was based on stepwise multiple linear regression analysis. Concurrent validity, diagnostic accuracy, and cross validation were statistically verified on the basis of the Spearman rank-order correlation coefficient (r s ), several estimates of the receiver operating characteristics plus the likelihood ratio, and iterated internal cross correlations. Ratings of breathiness from four experts with moderate reliability were used. Stepwise multiple regression analysis yielded a nine-variable acoustic model for the multiparametric measurement of breathiness (Acoustic Breathiness Index [ABI]). A strong correlation was found between ABI and auditory-perceptual rating (r s  = 0.840, P = 0.000). The cross correlations confirmed a comparably high degree of association. Additionally, the receiver operating characteristics and likelihood ratio results showed the best diagnostic outcome at a threshold of ABI = 3.44 with a sensitivity of 82.4% and a specificity of 92.9%. This study developed a new acoustic multivariate correlate for the evaluation of breathiness in voice. The ABI model showed valid and robust results and is therefore proposed as a new acoustic index for the evaluation of breathiness. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  6. Estimation of liquid properties by inverse problem analysis based on shear horizontal surface acoustic wave sensor responses (United States)

    Ueda, Kento; Kondoh, Jun


    A shear horizontal surface acoustic wave (SH-SAW) sensor can detect liquid properties, such as viscosity, density, permittivity, and conductivity. The advantage of using the SH-SAW sensors is the simultaneous detection of the mechanical and electrical properties of liquids. In this paper, we proposed a method of estimating the density and viscosity of liquids based on the inverse problem analysis. Glycerol or ethanol aqueous solutions were measured. The estimated and literature values were compared. For glycerol aqueous solutions, when the concentration is low, those values agree well. However, when the concentration is high, those values did not agree because the bulk modulus of glycerin solutions cannot be assumed as constant. On the other hand, as the bulk modulus of ethanol aqueous solutions can be assumed to be the same as that of water, the deviations between those values were small. Therefore, the proposed method is effective when the bulk modulus is assumed as constant.

  7. Acoustic Center or Time Origin?

    DEFF Research Database (Denmark)

    Staffeldt, Henrik


    The paper discusses the acoustic center in relation to measurements of loudspeaker polar data. Also, it presents the related concept time origin and discusses the deviation that appears between positions of the acoustic center found by wavefront based and time based measuring methods....

  8. Non linear analysis of obliquely propagating spin electron acoustic wave in a partially spin polarized degenerate plasma (United States)

    Iqbal, Z.; Murtaza, G.


    By employing the separated spin evolution quantum hydrodynamic model, non-linear evolution of obliquely propagating spin electron acoustic wave (SEAW) is presented. The solitary structures of SEAW is investigated through the Korteweg-de Vries (KdV) equation derived using reductive perturbation method. From the first order perturbations we derive the dispersion relation of SEAW and find that both the spin polarization and the propagation angle reduce the phase velocity while the electron streaming enhances it. Using small amplitude approximation, the solitary structure of SEAW is analyzed and the effects of spin polarization, propagation angle and electron streaming on the SEA soliton are studied. Our numerical results demonstrate that the spin polarization and the propagation angle play a balancing act on the soliton structures. The possible applications of our investigation to the astrophysical environments like white dwarfs is also discussed.

  9. Acoustical Semi-blind Deconvolution for Bearing Defect Detection

    Directory of Open Access Journals (Sweden)

    Wang Yu


    Full Text Available Acoustical machine monitoring is frequently complicated by noisy environments at a production site. This paper presents a semi-blind deconvolution algorithm to extract only one desired acoustic source signal from different sources which are convoluted and mixed by mechanical systems before being measured. The method is based on blind model transformation, robust independent component analysis, reference signal and spectral distance. The new algorithm is tested on simulation and experimental cases. Results demonstrate that blind separation of acoustic signals is possible even when measurements are distanced from vibration exciting sources of faulty bearings. Furthermore, the method can eliminate the effect of structural resonances and large reverberation time of mixtures, which often causes severe problems in classical acoustical diagnostic methods of rolling element bearings.

  10. Imaging acoustic sources moving at high-speed (United States)

    Bodony, Daniel; Papanicolaou, George


    In the quantification of the noise radiated by a turbulent flow the source motion is important. It is well known that moving acoustic sources radiate sound preferrentially in the direction of motion in a phenomenon termed `convective amplification.' Modern acoustic theories have utilized this behavior in their predictions. In the inverse problem the imaging of noise sources, by techniques such as beam forming, the source motion is not explicitly taken into account. In this talk we consider the imaging of acoustic sources moving at speeds on the order of the the ambient speed of sound, as typical of high-speed jets, for which the D"oppler shift approximation is not appropriate. An analysis will be presented that can be used to estimate the source motion based on the radiated acoustic field.

  11. Electromagnetic energy harvester for harvesting acoustic energy

    Indian Academy of Sciences (India)

    Farid U Khan

    giadis et al [10] respectively. Moreover, acoustical noise is also present in abundance in the surroundings [11–15]. Converting ambient acoustical noise with an acoustic energy (AEH) into a useful electrical power is most appropriate for applications like health monitoring of vehicles, machineries, buildings and bridges.

  12. Measuring acoustic habitats. (United States)

    Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E


    1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies.

  13. Acoustic biosensors. (United States)

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A


    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  14. Community Response to Multiple Sound Sources: Integrating Acoustic and Contextual Approaches in the Analysis

    Directory of Open Access Journals (Sweden)

    Peter Lercher


    Full Text Available Sufficient data refer to the relevant prevalence of sound exposure by mixed traffic sources in many nations. Furthermore, consideration of the potential effects of combined sound exposure is required in legal procedures such as environmental health impact assessments. Nevertheless, current practice still uses single exposure response functions. It is silently assumed that those standard exposure-response curves accommodate also for mixed exposures—although some evidence from experimental and field studies casts doubt on this practice. The ALPNAP-study population (N = 1641 shows sufficient subgroups with combinations of rail-highway, highway-main road and rail-highway-main road sound exposure. In this paper we apply a few suggested approaches of the literature to investigate exposure-response curves and its major determinants in the case of exposure to multiple traffic sources. Highly/moderate annoyance and full scale mean annoyance served as outcome. The results show several limitations of the current approaches. Even facing the inherent methodological limitations (energy equivalent summation of sound, rating of overall annoyance the consideration of main contextual factors jointly occurring with the sources (such as vibration, air pollution or coping activities and judgments of the wider area soundscape increases the variance explanation from up to 8% (bivariate, up to 15% (base adjustments up to 55% (full contextual model. The added predictors vary significantly, depending on the source combination. (e.g., significant vibration effects with main road/railway, not highway. Although no significant interactions were found, the observed additive effects are of public health importance. Especially in the case of a three source exposure situation the overall annoyance is already high at lower levels and the contribution of the acoustic indicators is small compared with the non-acoustic and contextual predictors. Noise mapping needs to go down to

  15. Community Response to Multiple Sound Sources: Integrating Acoustic and Contextual Approaches in the Analysis. (United States)

    Lercher, Peter; De Coensel, Bert; Dekonink, Luc; Botteldooren, Dick


    Sufficient data refer to the relevant prevalence of sound exposure by mixed traffic sources in many nations. Furthermore, consideration of the potential effects of combined sound exposure is required in legal procedures such as environmental health impact assessments. Nevertheless, current practice still uses single exposure response functions. It is silently assumed that those standard exposure-response curves accommodate also for mixed exposures-although some evidence from experimental and field studies casts doubt on this practice. The ALPNAP-study population ( N = 1641) shows sufficient subgroups with combinations of rail-highway, highway-main road and rail-highway-main road sound exposure. In this paper we apply a few suggested approaches of the literature to investigate exposure-response curves and its major determinants in the case of exposure to multiple traffic sources. Highly/moderate annoyance and full scale mean annoyance served as outcome. The results show several limitations of the current approaches. Even facing the inherent methodological limitations (energy equivalent summation of sound, rating of overall annoyance) the consideration of main contextual factors jointly occurring with the sources (such as vibration, air pollution) or coping activities and judgments of the wider area soundscape increases the variance explanation from up to 8% (bivariate), up to 15% (base adjustments) up to 55% (full contextual model). The added predictors vary significantly, depending on the source combination. (e.g., significant vibration effects with main road/railway, not highway). Although no significant interactions were found, the observed additive effects are of public health importance. Especially in the case of a three source exposure situation the overall annoyance is already high at lower levels and the contribution of the acoustic indicators is small compared with the non-acoustic and contextual predictors. Noise mapping needs to go down to levels of 40 d

  16. Community Response to Multiple Sound Sources: Integrating Acoustic and Contextual Approaches in the Analysis (United States)

    Lercher, Peter; De Coensel, Bert; Dekonink, Luc; Botteldooren, Dick


    Sufficient data refer to the relevant prevalence of sound exposure by mixed traffic sources in many nations. Furthermore, consideration of the potential effects of combined sound exposure is required in legal procedures such as environmental health impact assessments. Nevertheless, current practice still uses single exposure response functions. It is silently assumed that those standard exposure-response curves accommodate also for mixed exposures—although some evidence from experimental and field studies casts doubt on this practice. The ALPNAP-study population (N = 1641) shows sufficient subgroups with combinations of rail-highway, highway-main road and rail-highway-main road sound exposure. In this paper we apply a few suggested approaches of the literature to investigate exposure-response curves and its major determinants in the case of exposure to multiple traffic sources. Highly/moderate annoyance and full scale mean annoyance served as outcome. The results show several limitations of the current approaches. Even facing the inherent methodological limitations (energy equivalent summation of sound, rating of overall annoyance) the consideration of main contextual factors jointly occurring with the sources (such as vibration, air pollution) or coping activities and judgments of the wider area soundscape increases the variance explanation from up to 8% (bivariate), up to 15% (base adjustments) up to 55% (full contextual model). The added predictors vary significantly, depending on the source combination. (e.g., significant vibration effects with main road/railway, not highway). Although no significant interactions were found, the observed additive effects are of public health importance. Especially in the case of a three source exposure situation the overall annoyance is already high at lower levels and the contribution of the acoustic indicators is small compared with the non-acoustic and contextual predictors. Noise mapping needs to go down to levels of 40 d

  17. [Acoustic characteristics of classrooms]. (United States)

    Koszarny, Zbigniew; Chyla, Andrzej


    Quality and usefulness of school rooms for transmission of verbal information depends on the two basic parameters: form and quantity of the reverberation time, and profitable line measurements of school rooms from the acoustic point of view. An analysis of the above-mentioned parameters in 48 class rooms and two gymnasiums in schools, which were built in different periods, shows that the most important problem is connected with too long reverberation time and inappropriate acoustic proportions. In schools built in the 1970s, the length of reverberation time is mostly within a low frequency band, while in schools built contemporarily, the maximum length of disappearance time takes place in a quite wide band of 250-2000 Hz. This exceeds optimal values for that kind of rooms at least twice, and five times in the newly built school. A long reverberation time is connected with a low acoustic absorption of school rooms. Moreover, school rooms are characterised by inappropriate acoustic proportions. The classrooms, in their relation to the height, are too long and too wide. It is connected with deterioration of the transmission of verbal information. The data show that this transmission is unequal. Automatically, it leads to a speech disturbance and difficulties with understanding. There is the need for adaptation of school rooms through increase of an acoustic absorption.

  18. Experimental and Theoretical Analysis for a Fluid-Loaded, Simply Supported Plate Covered by a Damping and Decoupling Composite Acoustic Coating

    Directory of Open Access Journals (Sweden)

    Baihua Yuan


    Full Text Available This work presents a vibroacoustic response model for a fluid-loaded, simply supported rectangular plate covered by a composite acoustic coating consisting of damping and decoupling layers. The model treated the damping layer and base plate as a unified whole under pure bending moments and the decoupling layer as a three-dimensional, isotropic, linear elastic solid. The validity of the model was verified by both numerical analysis and experiments and was shown to accurately extend previous studies that were limited to a plate covered by a single damping or decoupling layer with an evaluation confined solely to numerical analysis. The trends of the numerical and experimental results are generally consistent, with some differences due to the influences of water pressure and the frequency dependence of the material parameters, which are not taken into account by the numerical analysis. Both experimental and numerical results consistently show that the radiated noise reduction effect of the composite coating is superior to that of single-type coatings, which is attributed to the fact that the composite coating combines the merits of both the high vibration suppression performance of the damping layer and the superior vibration isolation performance of the decoupling layer.

  19. Signal Analysis Algorithms for Optimized Fitting of Nonresonant Laser Induced Thermal Acoustics Damped Sinusoids (United States)

    Balla, R. Jeffrey; Miller, Corey A.


    This study seeks a numerical algorithm which optimizes frequency precision for the damped sinusoids generated by the nonresonant LITA technique. It compares computed frequencies, frequency errors, and fit errors obtained using five primary signal analysis methods. Using variations on different algorithms within each primary method, results from 73 fits are presented. Best results are obtained using an AutoRegressive method. Compared to previous results using Prony s method, single shot waveform frequencies are reduced approx.0.4% and frequency errors are reduced by a factor of approx.20 at 303K to approx. 0.1%. We explore the advantages of high waveform sample rates and potential for measurements in low density gases.

  20. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J


    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...

  1. Positive amplitude electron acoustic solitary waves in auroral plasma (United States)

    Ghosh, S. S.; Lakhina, G. S.

    Rapidly moving positive potential pulses have been observed by FAST and POLAR satellites in downward current region of auroral plasma. They are characterized by their high velocities (> 1000 km/s) which are of the order of the electron drift velocities and are found to be associated with electron beams. Interestingly, it is observed that the width of such electron mode solitary waves increases with the amplitude [Ergun et al. (1998)]. Theoretically, they are interpreted as BGK electron phase space holes. However, Berthomier et al. (2000) have shown that a positive amplitude solitary wave may well exist for an electron acoustic mode. According to a weakly nonlinear theory, the width of such an electron acoustic solitary wave is expected to decrease with increasing amplitude which contradicts the observation. On the other hand, in our previous work, we have shown that the width of a large amplitude rarefactive ion acoustic solitary wave increases with an increasing amplitude [Ghosh et al. (2004)]. In the present work, we have extended our analysis to an electron acoustic solitary wave. A fully nonlinear solution of positive amplitude electron acoustic solitary waves (electron acoustic solitary holes) has been obtained by adopting the Sagdeev pseudopotetial technique. The plasma is assumed to be magnetized and traversed by the electron beam. The existence domain of such electron acoustic solitary holes is studied in detail. It is found that the width of electron acoustic solitary holes increases with increasing amplitude. Theoretically estimated width-amplitude variation profiles have been compared with recent satellite observations. It is proposed that a model based on electron acoustic mode may well interpret the fast moving solitary holes for an appropriate parameter space. References:Berthomier et al., Phys. Plasma, 7, 2987 (2000).Ergun et al., Phys. Rev. Lett., 81, 826, (1998).Ghosh and Lakhina,, Nonlin. Process. Geophys, (2004), (to be appeared).

  2. Quantitative acoustic analysis of the vocal repertoire of the golden rocket frog (Anomaloglossus beebei). (United States)

    Pettitt, Beth A; Bourne, Godfrey R; Bee, Mark A


    This study describes the vocal repertoire of the Guyanan golden rocket frog, Anomaloglossus beebei, a bromeliad specialist with biparental care. Using multivariate analyses of nine call properties, as well as the occurrence of nonlinear phenomena, three signal types were distinguished-advertisement, courtship, and aggressive calls. Although all three call types were composed of a short series of rapidly repeated pulses, advertisement calls were produced at higher amplitudes and had longer pulse durations than both courtship calls and aggressive calls. Courtship calls exhibited lower dominant frequencies than both advertisement and aggressive calls, which had similar dominant frequencies. Aggressive calls had more pulses per call, had longer intervals between calls, and occasionally contained one or two introductory pulses preceding the pulsed call. Several acoustic properties predicted aspects of the signaler's body size and condition. Our study demonstrates the reliability of human observers to differentiate the multiple call types of A. beebei based on hearing calls and observing the social context in which they are produced under field conditions.

  3. Theoretical analysis of transcranial magneto-acoustical stimulation with Hodgkin–Huxley neuron model

    Directory of Open Access Journals (Sweden)

    Yi eYuan


    Full Text Available Transcranial magneto-acoustical stimulation (TMAS is a novel stimulation technology in which an ultrasonic wave within a magnetostatic field generates an electric current in an area of interest in the brain to modulate neuronal activities. As a key part of the neural network, neurons transmit information in the nervous system. However, the effect of TMAS on the neuronal firing rhythm remains unknown. To address this problem, we investigated the stimulatory mechanism of TMAS on neurons with a Hodgkin-Huxley neuron model. The simulation results indicate that the magnetostatic field intensity and ultrasonic power can affect the amplitude and interspike interval of neuronal action potential under continuous wave ultrasound. The simulation results also show that the ultrasonic power, duty cycle and repetition frequency can alter the firing rhythm of neural action potential under pulsed ultrasound. This study can help to reveal and explain the biological mechanism of TMAS and to provide a theoretical basis for TMAS in the treatment or rehabilitation of neuropsychiatric disorders.

  4. Analysis of the spectrum of a Cartesian Perfectly Matched Layer (PML) approximation to acoustic scattering problems

    KAUST Repository

    Kim, Seungil


    In this paper, we study the spectrum of the operator which results when the Perfectly Matched Layer (PML) is applied in Cartesian geometry to the Laplacian on an unbounded domain. This is often thought of as a complex change of variables or "complex stretching." The reason that such an operator is of interest is that it can be used to provide a very effective domain truncation approach for approximating acoustic scattering problems posed on unbounded domains. Stretching associated with polar or spherical geometry lead to constant coefficient operators outside of a bounded transition layer and so even though they are on unbounded domains, they (and their numerical approximations) can be analyzed by more standard compact perturbation arguments. In contrast, operators associated with Cartesian stretching are non-constant in unbounded regions and hence cannot be analyzed via a compact perturbation approach. Alternatively, to show that the scattering problem PML operator associated with Cartesian geometry is stable for real nonzero wave numbers, we show that the essential spectrum of the higher order part only intersects the real axis at the origin. This enables us to conclude stability of the PML scattering problem from a uniqueness result given in a subsequent publication. © 2009 Elsevier Inc. All rights reserved.

  5. The Acoustic Analysis of Voice Onset Time in Cochlear Implanted Children and Normal-Hearing Controls

    Directory of Open Access Journals (Sweden)

    Dr. Shohreh Jalaie


    Full Text Available Background and Aim: Hearing has an important role in speech production and making phonological distinction, especially voicing distinction. Voice onset time (VOT has been a reliable acoustic cue of voicing differences in plosive consonants. The purpose of this study was to measure VOT in initial Persian (Farsi oral plosives produced by cochlear implanted children, comparing to normal hearing children. Methods: In this cross-sectional study, 20 cases and 20 controls were assessed. Cases were prelingually deaf children who were cochlear implanted 4.5 years prior to test. Controls were normal hearing children at 4.5 years of age. VOT were measured while children uttered oral plosives. The effect of hearing status, voicing, and gender on VOT were assessed. Results: The amount of VOT of plosives produced by girls was higher than boys, in both groups. This difference was significantly higher in voiceless plosives than in voiced ones. In both groups, voiceless plosives had long-positive VOT value; while the amount of VOT was short-positive regarding voiced plosives. Conclusion: It was demonstrated that VOT is significantly correlated with voicing. In voiceless plosives, VOT could not be considered as a phonetic correlate of hearing status; whereas it made significant differences between cochlear implanted children and hearing controls. Furthermore, it was confirmed that concerning voiceless plosives, the amount of VOT of girls was significantly higher than boys. On the contrary, in voiced plosives, gender had no significant effect on the amount of VOT.

  6. A study of vocal nonlinearities in humpback whale songs: from production mechanisms to acoustic analysis (United States)

    Cazau, Dorian; Adam, Olivier; Aubin, Thierry; Laitman, Jeffrey T.; Reidenberg, Joy S.


    Although mammalian vocalizations are predominantly harmonically structured, they can exhibit an acoustic complexity with nonlinear vocal sounds, including deterministic chaos and frequency jumps. Such sounds are normative events in mammalian vocalizations, and can be directly traceable to the nonlinear nature of vocal-fold dynamics underlying typical mammalian sound production. In this study, we give qualitative descriptions and quantitative analyses of nonlinearities in the song repertoire of humpback whales from the Ste Marie channel (Madagascar) to provide more insight into the potential communication functions and underlying production mechanisms of these features. A low-dimensional biomechanical modeling of the whale’s U-fold (vocal folds homolog) is used to relate specific vocal mechanisms to nonlinear vocal features. Recordings of living humpback whales were searched for occurrences of vocal nonlinearities (instabilities). Temporal distributions of nonlinearities were assessed within sound units, and between different songs. The anatomical production sources of vocal nonlinearities and the communication context of their occurrences in recordings are discussed. Our results show that vocal nonlinearities may be a communication strategy that conveys information about the whale’s body size and physical fitness, and thus may be an important component of humpback whale songs.

  7. Acoustic sensing from small-size UAVs (United States)

    Robertson, Dale N.; Pham, Tien; Edge, Harris; Porter, Brian; Shumaker, Justin; Cline, Duane


    As part of a research initiative within the US Army Research Laboratory, we investigate acoustic sensing capability from UAVs for remote Intelligence Surveillance and Reconnaissance (ISR) applications. Acoustic sensing from UAVs offers several advantages over acoustic sensing on the ground including: (i) longer detection ranges due to upward refraction and (ii) a single elevated acoustic array (versus multiple acoustic arrays on the ground) can provide a pointing vector to the acoustic source on the ground. However, there are technical challenges with having acoustic sensors on UAVs which involve self generated noise from the platform and the air flow. In this paper, we describe our current work with acoustic sensors on small UAV platforms and present preliminary processing results from a recent field experiment.

  8. Practical acoustic emission testing

    CERN Document Server


    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.

  9. Experimental Investigation on the Fracture Behavior of Black Shale by Acoustic Emission Monitoring and CT Image Analysis during Uniaxial Compression (United States)

    Wang, Y.; Li, C. H.; Hu, Y. Z.


    Plenty of mechanical experiments have been done to investigate the deformation and failure characteristics of shale; however, the anisotropic failure mechanism has not been well studied. Here, laboratory Uniaxial Compressive Strength (UCS) tests on cylindrical shale samples obtained by drilling at different inclinations to bedding plane were performed. The failure behaviors of the shale samples were studied by real-time acoustic emission (AE) monitoring and post-test X-ray computer tomography (CT) analysis. The experimental results suggest that the pronounced bedding planes of shale have a great influence on the mechanical properties and AE patterns. The AE counts and AE cumulative energy release curves clearly demonstrate different morphology, and the `U' shaped curve relationship between the AE counts, AE cumulative energy release and bedding inclination was first documented. The post-test CT image analysis shows the crack patterns via 2D image reconstructions, an index of stimulated fracture density is defined to represent the anisotropic failure mode of shale. What is more, the most striking finding is that the AE monitoring results are in good agreement with the CT analysis. The structural difference in the shale sample is the controlling factor resulting in the anisotropy of AE patterns. The pronounced bedding structure in the shale formation results in an anisotropy of elasticity, strength, and AE information from which the changes in strength dominate the entire failure pattern of the shale samples.

  10. 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)


    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.

  11. Portuguese Cistercian Churches - An acoustic legacy (United States)

    Rodrigues, Fabiel G.; Lanzinha, João C. G.; Martins, Ana M. T.


    The Cistercian Order (11th century) stands out as an apologist of the simplicity and austerity of the space. According to the Order of Cîteaux, only with an austere space, without any distractions, the true spiritual contemplation is achieved. This Order was an aggregator and consolidator pole during the Christian Reconquest. Thus, as it happens with other Religious Orders, Cîteaux has a vast heritage legacy. This heritage is witness, not only of the historical, but also social, political, and spiritual evolution. This legacy resumes the key principles to an austere liturgy, which requirements, in the beginning, are based on the simplicity of worship and of the connection between man and God. Later, these requirements allowed the development of the liturgy itself and its relation with the believers. Consequently, it can be concisely established an empirical approach between the Cistercian churches and the acoustics conditioning of these spaces. This outcome is fundamental in order to understand the connection between liturgy and the conception of the Cistercian churches as well as the constructed space and its history. So, an analysis of these principles is essential to establish the relation between acoustic and religious buildings design throughout history. It is also a mean of understanding the knowledge of acoustics principles that the Cistercian Order bequeathed to Portugal. This paper presents an empirical approach on Cistercian monastic churches acoustics. These spaces are the place where the greatest acoustic efforts are concentrated and it is also the space where the liturgy reaches greater importance. On the other hand, Portugal is a country which has an important Cistercian legacy over several periods of history. Consequently, the Portuguese Cistercian monastic churches are representative of the development of the liturgy, the design of spaces and of the acoustic requirements of their churches since the 12th century until the 21st century and it is of

  12. Underwater Acoustic Networking Techniques

    CERN Document Server

    Otnes, Roald; Casari, Paolo; Goetz, Michael; Husøy, Thor; Nissen, Ivor; Rimstad, Knut; van Walree, Paul; Zorzi, Michele


    This literature study presents an overview of underwater acoustic networking. It provides a background and describes the state of the art of all networking facets that are relevant for underwater applications. This report serves both as an introduction to the subject and as a summary of existing protocols, providing support and inspiration for the development of network architectures.

  13. Analysis of gas jetting and fumarole acoustics at Aso Volcano, Japan (United States)

    McKee, Kathleen; Fee, David; Yokoo, Akihiko; Matoza, Robin S.; Kim, Keehoon


    The gas-thrust region of a large volcanic eruption column is predominately a momentum-driven, fluid flow process that perturbs the atmosphere and produces sound akin to noise from jet and rocket engines, termed ;jet noise;. We aim to enhance understanding of large-scale volcanic jets by studying an accessible, less hazardous fumarolic jet. We characterize the acoustic signature of 2.5-meter wide vigorously jetting fumarole at Aso Volcano, Japan using a 5-element infrasound array located on the nearby crater. The fumarole opened on 13 July 2015 on the southwest flank of the partially collapsed pyroclastic cone within Aso Volcano's Naka-dake crater and had persistent gas jetting, which produced significant audible jet noise. The array was 220 m from the fumarole and 57.6° from the vertical jet axis, a recording angle not typically feasible in volcanic environments. Array processing is performed to distinguish fumarolic jet noise from wind. Highly correlated periods are characterized by sustained, low-amplitude signal with a 7-10 Hz spectral peak. Finite difference time domain method numerical modeling suggests the influence of topography near the vent and along the propagation path significantly affects the spectral content, complicating comparisons with laboratory jet noise. The fumarolic jet has a low estimated Mach number (0.3 to 0.4) and measured temperature of 260 °C. The Strouhal number for infrasound from volcanic jet flows and geysers is not known; thus we assume a peak Strouhal number of 0.19 based on pure-air laboratory jet experiments. This assumption leads to an estimated exit velocity of the fumarole of 79 to 132 m/s. Using published gas composition data from 2003 to 2009, the fumarolic vent area estimated from thermal infrared images, and estimated jet velocity, we estimate total volatile flux at 160-270 kg/s (14,000-23,000 t/d).

  14. Analysis of gas jetting and fumarole acoustics at Aso Volcano, Japan

    Energy Technology Data Exchange (ETDEWEB)

    McKee, Kathleen; Fee, David; Yokoo, Akihiko; Matoza, Robin S.; Kim, Keehoon


    The gas-thrust region of a large volcanic eruption column is predominately a momentum-driven, fluid flow process that perturbs the atmosphere and produces sound akin to noise from jet and rocket engines, termed “jet noise”. We aim to enhance understanding of large-scale volcanic jets by studying an accessible, less hazardous fumarolic jet. We characterize the acoustic signature of ~ 2.5-meter wide vigorously jetting fumarole at Aso Volcano, Japan using a 5-element infrasound array located on the nearby crater. The fumarole opened on 13 July 2015 on the southwest flank of the partially collapsed pyroclastic cone within Aso Volcano's Naka-dake crater and had persistent gas jetting, which produced significant audible jet noise. The array was ~ 220 m from the fumarole and 57.6° from the vertical jet axis, a recording angle not typically feasible in volcanic environments. Array processing is performed to distinguish fumarolic jet noise from wind. Highly correlated periods are characterized by sustained, low-amplitude signal with a 7–10 Hz spectral peak. Finite difference time domain method numerical modeling suggests the influence of topography near the vent and along the propagation path significantly affects the spectral content, complicating comparisons with laboratory jet noise. The fumarolic jet has a low estimated Mach number (0.3 to 0.4) and measured temperature of ~ 260 °C. The Strouhal number for infrasound from volcanic jet flows and geysers is not known; thus we assume a peak Strouhal number of 0.19 based on pure-air laboratory jet experiments. This assumption leads to an estimated exit velocity of the fumarole of ~ 79 to 132 m/s. Using published gas composition data from 2003 to 2009, the fumarolic vent area estimated from thermal infrared images, and estimated jet velocity, we estimate total volatile flux at ~ 160–270 kg/s (14,000–23,000 t/d).

  15. Operative Mortality Rates of Acoustic Neuroma Surgery: A National Cancer Database Analysis. (United States)

    McClelland, Shearwood; Kim, Ellen; Murphy, James D; Jaboin, Jerry J


    Optimal acoustic neuroma (AN) management involves choosing between three treatment modalities: microsurgical excision, radiation, or observation with serial imaging. The reported in-hospital mortality rate of surgery for AN in the United States is 0.5%. However, there has yet to be a nationwide examination of the AN surgery mortality rate encompassing the period beyond initial hospital discharge. The National Cancer Data Base (NCDB) from 2004 to 2013 identified AN patients receiving surgery. Multivariate logistic regression assessed 30-day operative mortality, adjusting for several variables including patient age, race, sex, income, geographic region, primary payer for care, tumor size, and medical comorbidities. Ten thousand one hundred thirty six patients received surgery as solitary treatment for AN. Mortality at 30 days postoperatively occurred in 49 patients (0.5%); only a Charlson/Deyo score of 2 (odds ratio [OR] = 6.6;95% confidence interval [CI] = 2.6-16.6; p = 0.002) was predictive of increased mortality. No other patient demographic including African-American race, minimum age of 65 or government insurance was predictive of 30-day operative mortality. The 30-day mortality rate following surgery for AN is 1 of 200 (0.5%), equivalent to the established in-hospital operative mortality rate, and 2.5 times higher than the cumulative assessment from single-center studies. No patient demographic other than increasing medical comorbidities reached significance in predicting 30-day operative mortality. The nearly identical rates of 30-day and in-hospital mortality from separate nationwide analyses indicate that nearly all of the operative mortality occurs before initial postoperative discharge from the hospital. This mortality rate provides a framework for comparing the true risks and benefits of surgery versus radiation or observation for AN.

  16. Acoustic microscopy

    CERN Document Server

    Briggs, Andrew


    For many years 'Acoustic Microscopy' has been the definitive book on the subject. A key development since it was first published has been the development of ultrasonic force microscopy. This edition has a major new chapter on this technique and its applications.

  17. Experiments for possible hydroacoustic discrimination of free-swimming juvenile gadoid fish by analysis of broadband pulse spectra as well as 3D fish position form video images and split beam acoustics

    DEFF Research Database (Denmark)

    Lundgren, Bo; Nielsen, J. Rasmus


    Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad-bandwidth ec......Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad......, alignment of acoustic and optical-reference frames, and automatic position-fitting of fish models to manually marked fix-points on fish images. The software also performs Fourier spectrum analysis and pulse-shape analysis of broad-bandwidth echoes. Therefore, several measurement series on free...

  18. Understanding irony: an ERP analysis on the elaboration of acoustic ironic statements

    Directory of Open Access Journals (Sweden)

    Amenta Simona


    Full Text Available Irony is part of our daily experience, that is probably the reason why a lot of studies have been trying to define its nature and the way we are able to understand the pragmatic intentions lying behind ironic communication. This study addresses the issue of pragmatic comprehension of language by analysing the differences or similarities in processing ironical and non-ironical language. The aim of the study is specifically to explore neuropsychological correlates (ERPs of irony decoding. 10 subjects listened to 240 sentences presenting a counterfactual vs. non-counterfactual content (counterfactual modality and spoken with ironical vs. neutral prosody (prosody modality. ERPs analysis showed a negative deflection peaking at about 460ms post stimulus onset (N400 for all the conditions. Statistical analyses (repeated measures ANOVA applied to peak amplitudes showed no statistically significant differences between the conditions as a functions of the type of sentence (ironical vs. non ironical and the content of ironical sentences (counterfactual vs. non counterfactual. An increase of N400 related to ironical sentences was observed although no statistical significant differences between ironical and non ironical sentences were found. The absence of an N400 effect may indicate that irony is not treated as a semantic anomaly, thus rejecting the standard pragmatic hypothesis. The observed differences in amplitude could be probably attributed to a higher requirement for the cognitive resources in order to integrate contrasting and complex lexical, prosodic and contextual cues.

  19. Vocal acoustic analysis as a biometric indicator of information processing: implications for neurological and psychiatric disorders. (United States)

    Cohen, Alex S; Dinzeo, Thomas J; Donovan, Neila J; Brown, Caitlin E; Morrison, Sean C


    Vocal expression reflects an integral component of communication that varies considerably within individuals across contexts and is disrupted in a range of neurological and psychiatric disorders. There is reason to suspect that variability in vocal expression reflects, in part, the availability of "on-line" resources (e.g., working memory, attention). Thus, understanding vocal expression is a potentially important biometric index of information processing, not only across but within individuals over time. A first step in this line of research involves establishing a link between vocal expression and information processing systems in healthy adults. The present study employed a dual attention experimental task where participants provided natural speech while simultaneously engaged in a baseline, medium or high nonverbal processing-load task. Objective, automated, and computerized analysis was employed to measure vocal expression in 226 adults. Increased processing load resulted in longer pauses, fewer utterances, greater silence overall and less variability in frequency and intensity levels. These results provide compelling evidence of a link between information processing resources and vocal expression, and provide important information for the development of an automated, inexpensive and uninvasive biometric measure of information processing. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Analysis of Onstage Acoustics Preference of Musicians of Traditional Performance of Javanese Gamelan Based on Normalized Autocorrelation Function

    Directory of Open Access Journals (Sweden)



    Full Text Available On-stage sound field analysis of a traditional performance of the Javanese gamelan at Pendopo ISI Surakarta, Indonesia was conducted by analyzing the effective decay time of a normalized autocorrelation function called tau-e, , during a performance of the Gambyong Pare Anom dance. The parameter tau-e is used to describe the richness of the frequency content, tempo, and types of gamelan instruments being played at a certain time and position on stage. The tau-e parameter is important for musicians in order to maintain communication between each other such that they can keep the performance in harmony. In order to determine the acoustic parameters heard by gamelan musicians on stage, sound measurements were conducted at 4 points on stage during a performance. Each position represents a specific group of gamelan instruments, which have different characteristics of loudness and frequency, different functions and different ways the instruments are played. The analysis showed that each of the four positions had a different value of , which fluctuated throughout the performance. Overall, the dominant at position 1 was 20 ms; at position 2 it was 50 ms; at position 3 it was 20 ms; and at position 4 it was 40 ms. The distribution of on the stage shows that positions 1 and 3 had more frequency richness compared to positions 2 and 4.

  1. Cluster analysis of stress corrosion mechanisms for steel wires used in bridge cables through acoustic emission particle swarm optimization. (United States)

    Li, Dongsheng; Yang, Wei; Zhang, Wenyao


    Stress corrosion is the major failure type of bridge cable damage. The acoustic emission (AE) technique was applied to monitor the stress corrosion process of steel wires used in bridge cable structures. The damage evolution of stress corrosion in bridge cables was obtained according to the AE characteristic parameter figure. A particle swarm optimization cluster method was developed to determine the relationship between the AE signal and stress corrosion mechanisms. Results indicate that the main AE sources of stress corrosion in bridge cables included four types: passive film breakdown and detachment of the corrosion product, crack initiation, crack extension, and cable fracture. By analyzing different types of clustering data, the mean value of each damage pattern's AE characteristic parameters was determined. Different corrosion damage source AE waveforms and the peak frequency were extracted. AE particle swarm optimization cluster analysis based on principal component analysis was also proposed. This method can completely distinguish the four types of damage sources and simplifies the determination of the evolution process of corrosion damage and broken wire signals. Copyright © 2017. Published by Elsevier B.V.

  2. Acoustic radiation force impulse imaging (ARFI) for differentiation of benign and malignant thyroid nodules--A meta-analysis. (United States)

    Zhan, Jia; Jin, Jia-Mei; Diao, Xue-Hong; Chen, Yue


    Work-up of thyroid nodules remains challenging. Acoustic radiation force impulse imaging (ARFI)-generated shear wave elastography, which can measure quantitatively tissue stiffness (virtual touch tissue quantification) is used as a complement to conventional sonography for improving the diagnosis of thyroid nodules. This meta-analysis was performed to expand on a previous meta-analysis to assess the diagnostic power of ARFI in differentiating benign and malignant thyroid nodules. The MEDLINE, PubMed, SpringerLink databases up to December 31, 2014, were searched. The pooled sensitivity, specificity, and summary receiver operating characteristic curve were obtained from individual studies with a random effects model. Sixteen studies that included a total of 2436 nodules in 2147 patients for ARFI studies were analyzed. The overall mean sensitivity and specificity of ARFI for differentiation of thyroid nodules were 0.80 (95% confidence interval [CI], 0.73-0.87) and 0.85 (95% CI, 0.80-0.90), respectively. A significant heterogeneity was found for both sensitivity and specificity of the different studies (P<0.001). The area under the curve for the ARFI was 0.91. ARFI has high sensitivity and specificity for identification of thyroid. This technique might be useful to select patients with thyroid nodules for surgery. Copyright © 2015. Published by Elsevier Ireland Ltd.

  3. Analysis and experimental study on the effect of a resonant tube on the performance of acoustic levitation devices

    Directory of Open Access Journals (Sweden)

    Hai Jiang


    Full Text Available The influence of a resonant tube on the performance of acoustic standing wave-based levitation device (acoustic levitation device hereinafter is studied by analyzing the acoustic pressure and levitation force of four types of acoustic levitation devices without a resonance tube and with resonance tubes of different radii R using ANSYS and MATLAB. Introducing a resonance tube either enhances or weakens the levitation strength of acoustic levitation device, depending on the resonance tube radii. Specifically, the levitation force is improved to a maximum degree when the resonance tube radius is slightly larger than the size of the reflector end face. Furthermore, the stability of acoustic levitation device is improved to a maximum degree by introducing a resonance tube of R=1.023λ. The experimental platform and levitation force measurement system of the acoustic levitation device with concave-end-face-type emitter and reflector are developed, and the test of suspended matters and liquid drops is conducted. Results show that the Φ6.5-mm steel ball is suspended easily when the resonance tube radius is 1.023λ, and the Φ5.5-mm steel ball cannot be suspended when the resonance tube radius is 1.251λ. The levitation capability of the original acoustic levitation device without a resonance tube is weakened when a resonance tube of R=1.251λ is applied. These results are consistent with the ANSYS simulation results. The levitation time of the liquid droplet with a resonance tube of R=1.023λ is longer than without a resonance tube. This result is also supported by the MATLAB simulation results. Therefore, the performance of acoustic levitation device can be improved by introducing a resonant tube with an appropriate radius.

  4. Signal Analysis of Helicopter Blade-Vortex-Interaction Acoustic Noise Data (United States)

    Rogers, James C.; Dai, Renshou


    Blade-Vortex-Interaction (BVI) produces annoying high-intensity impulsive noise. NASA Ames collected several sets of BVI noise data during in-flight and wind tunnel tests. The goal of this work is to extract the essential features of the BVI signals from the in-flight data and examine the feasibility of extracting those features from BVI noise recorded inside a large wind tunnel. BVI noise generating mechanisms and BVI radiation patterns an are considered and a simple mathematical-physical model is presented. It allows the construction of simple synthetic BVI events that are comparable to free flight data. The boundary effects of the wind tunnel floor and ceiling are identified and more complex synthetic BVI events are constructed to account for features observed in the wind tunnel data. It is demonstrated that improved recording of BVI events can be attained by changing the geometry of the rotor hub, floor, ceiling and microphone. The Euclidean distance measure is used to align BVI events from each blade and improved BVI signals are obtained by time-domain averaging the aligned data. The differences between BVI events for individual blades are then apparent. Removal of wind tunnel background noise by optimal Wiener-filtering is shown to be effective provided representative noise-only data have been recorded. Elimination of wind tunnel reflections by cepstral and optimal filtering deconvolution is examined. It is seen that the cepstral method is not applicable but that a pragmatic optimal filtering approach gives encouraging results. Recommendations for further work include: altering measurement geometry, real-time data observation and evaluation, examining reflection signals (particularly those from the ceiling) and performing further analysis of expected BVI signals for flight conditions of interest so that microphone placement can be optimized for each condition.

  5. 4th Pacific Rim Underwater Acoustics Conference

    CERN Document Server

    Xu, Wen; Cheng, Qianliu; Zhao, Hangfang


    These proceedings are a collection of 16 selected scientific papers and reviews by distinguished international experts that were presented at the 4th Pacific Rim Underwater Acoustics Conference (PRUAC), held in Hangzhou, China in October 2013. The topics discussed at the conference include internal wave observation and prediction; environmental uncertainty and coupling to sound propagation; environmental noise and ocean dynamics; dynamic modeling in acoustic fields; acoustic tomography and ocean parameter estimation; time reversal and matched field processing; underwater acoustic localization and communication as well as measurement instrumentations and platforms. These proceedings provide insights into the latest developments in underwater acoustics, promoting the exchange of ideas for the benefit of future research.

  6. Continued Analysis of High-Frequency Broadband Acoustic Scattering from Non-Linear Internal Waves during SW06 (United States)


    experiment. Almost coincident microstructure measurements were collected by Jim Moum with a profiling microstructure instrument, Chameleon . The...using the turbulence profiler Chameleon (Moum et al., 1995). The broadband acoustic system was fully operational throughout the experiment and high

  7. Acoustic tomography in the atmospheric surface layer

    Directory of Open Access Journals (Sweden)

    A. Ziemann

    Full Text Available Acoustic tomography is presented as a technique for remote monitoring of meteorological quantities. This method and a special algorithm of analysis can directly produce area-averaged values of meteorological parameters. As a result consistent data will be obtained for validation of numerical atmospheric micro-scale models. Such a measuring system can complement conventional point measurements over different surfaces. The procedure of acoustic tomography uses the horizontal propagation of sound waves in the atmospheric surface layer. Therefore, to provide a general overview of sound propagation under various atmospheric conditions a two-dimensional ray-tracing model according to a modified version of Snell's law is used. The state of the crossed atmosphere can be estimated from measurements of acoustic travel time between sources and receivers at different points. Derivation of area-averaged values of the sound speed and furthermore of air temperature results from the inversion of travel time values for all acoustic paths. Thereby, the applied straight ray two-dimensional tomographic model using SIRT (simultaneous iterative reconstruction technique is characterised as a method with small computational requirements, satisfactory convergence and stability properties as well as simple handling, especially, during online evaluation.

    Key words. Meteorology and atmospheric dynamics (turbulence; instruments and techniques.

  8. Incubation pit analysis and calculation of the hydrodynamic impact pressure from the implosion of an acoustic cavitation bubble. (United States)

    Tzanakis, I; Eskin, D G; Georgoulas, A; Fytanidis, D K


    An experimental study to evaluate cavitation bubble dynamics is conducted. The aim is to predict the magnitude and statistical distribution of hydrodynamic impact pressure generated from the implosion of various individual acoustic cavitation bubbles near to a rigid boundary, considering geometrical features of the pitted area. A steel sample was subjected to cavitation impacts by an ultrasonic transducer with a 5mm diameter probe. The pitted surface was then examined using high-precision 3D optical interferometer techniques. Only the incubation period where surface is plastically deformed without material loss is taken into account. The exposure time was adjusted in the range of 3-60 s to avoid pit overlapping and a special procedure for pit analysis and characterisation was then followed. Moreover, a high-speed camera device was deployed to capture the implosion mechanisms of cavitation bubbles near to the surface. The geometrical characteristics of single incubation pits as well as pit clusters were studied and their deformation patterns were compared. Consequently, a reverse engineering approach was applied in order the hydrodynamic impact pressure from the implosion of an individual cavitation bubble to be determined. The characteristic parameters of the cavitation implosion process such as hydrodynamic impact pressure and liquid micro-jet impact velocity as well as the hydrodynamic severity of the cavitation impacts were quantified. It was found that the length of the hypotenuse of the orthographic projections from the center of the pit, which basically represents the deformed area of the pit, increases with the hydrodynamic impact aggressiveness in a linear rate. Majority of the hydrodynamic impacts were in the range of 0.4-1 GPa while the corresponding micro-jet velocities were found to be in the range of 200-700 m/s. Outcomes of this study, contribute to further understanding the cavitation intensity from the implosion of acoustically generated bubbles and

  9. Detection of cracking and damage mechanisms in brittle granites by moment tensor analysis of acoustic emission signals (United States)

    Xu, Shi-da; Li, Yuan-hui; Liu, Jian-po


    An acoustic emission (AE) testing of rock cracking was performed under uniaxial loading conditions by precut varisized circular holes in selected brittle granites. Based on AE-source location technique and AE-theory for moment tensor analysis, rules of the temporal-spatial evolution of micro-cracks in different failure mechanisms were explored and types of micro-cracks were analyzed as well. The results revealed that the micro-cracks are uniquely easy to generate in the positions where stress are concentrated. Tensile fractures are easy to form on the roof and floor of a circular hole, while shear fractures are easy to be found on both sides. The locations of initial cracks generated around the holes in the loading process are the direction or vertical direction of maximum principle stress. Macroscopic crack orientation agrees with the direction of maximum principle stress approximately. As the size of circular opening increases and the relative size of pillar decreases, shear cracks are dominant with the percentage more than 45%, tension cracks are fewer, accounted for less than 40% of the total events, and mixed-mode cracks represent a minimum proportion, despite the decrease of percentage of shear cracks. The findings of this work can serve for supporting design of tunnel or roadway to avoid collapse.

  10. Acoustic analysis of speech through a hearing aid: consonant-vowel ratio effects with two-channel compression amplification. (United States)

    Hickson, L; Thyer, N; Bates, D


    In this study, the consonant-vowel ratio (CVR) changes associated with varying the compression ratio and crossover frequency of two-channel syllabic compression amplification were examined. Consonant-vowel syllables were recorded at 60 and 75 dB SPL input levels to the hearing aid under 13 different amplification conditions: 12 compression conditions and a condition that used linear amplification in both channels. Syllables consisted of voiceless stops, fricatives, and affricates combined with the vowels /a/, /i/, and /u/. Acoustic analysis of the processed syllables indicated that the CVR was generally increased with compression, compared to linear amplification, and that the effects were greatest for amplification with compression in the high-frequency channel. In addition, higher CVRs were obtained when the crossover frequency was raised. Compression in the low-frequency channel had the least effect on CVR. As previous research has indicated that CVR may serve as a cue to the perception of some consonant sounds by people with hearing impairment, the results suggest the need for caution with the application of high-frequency channel compression until the perceptual effects are fully investigated.

  11. The texture quantitative analysis of the normal mammary parenchyma and in breast lesions: acoustic radiation force impulse (ARFI) technology. (United States)

    Li, Y; Liu, C; Geng, J; Zheng, X; Chen, B; Lu, Z; Wang, X


    The purpose of this work is to investigate the feasibility of acoustic radiation force impulse (ARFI) technology in the normal mammary parenchyma and in breast lesions. The virtual touch tissue quantification (VTQ) value was measured on a total of 150 cases in the normal mammary parenchyma and a total of 69 cases in breast lesions (19 cases of nodules, 28 cases of fibroadenoma, and 22 cases of cancer). Then the statistic analysis was carried out on the VTQ value combined with mammographic density, ages, menstrual stages, and pathological result. The VTQ value of mammary parenchyma rose with the increase of the mammographic density, and the value of VTQ had statistical differences in the comparison of group C with group B and in the comparison of group D with group C. The comparison of the VTQ value of the mammary parenchyma in patients with breast cancer and the nodule had statistical difference. The comparison of the VTQ value of the mammary parenchyma in patients with breast cancer, and the fibroadenoma had statistical difference. The value ofVTQ in masses gradually increased in the groups of nodule, fibroadenoma, and breast cancer. There was significant difference in the comparison of VTQ value of the nodule group and the fibroadenoma group with breast cancer group respectively. ARFI-VTQ technology has some reference value in assessing mammographic density. ARFI-VTQ can be used as the quantitative indicater for differentially diagnosing the breast lesions.

  12. Intelligent Engine Systems: Acoustics (United States)

    Wojno, John; Martens, Steve; Simpson, Benjamin


    An extensive study of new fan exhaust nozzle technologies was performed. Three new uniform chevron nozzles were designed, based on extensive CFD analysis. Two new azimuthally varying variants were defined. All five were tested, along with two existing nozzles, on a representative model-scale, medium BPR exhaust nozzle. Substantial acoustic benefits were obtained from the uniform chevron nozzle designs, the best benefit being provided by an existing design. However, one of the azimuthally varying nozzle designs exhibited even better performance than any of the uniform chevron nozzles. In addition to the fan chevron nozzles, a new technology was demonstrated, using devices that enhance mixing when applied to an exhaust nozzle. The acoustic benefits from these devices applied to medium BPR nozzles were similar, and in some cases superior to, those obtained from conventional uniform chevron nozzles. However, none of the low noise technologies provided equivalent acoustic benefits on a model-scale high BPR exhaust nozzle, similar to current large commercial applications. New technologies must be identified to improve the acoustics of state-of-the-art high BPR jet engines.

  13. Internal Acoustics of the ISS and Other Spacecraft (United States)

    Allen, Christopher S.


    It is important to control the acoustic environment inside spacecraft and space habitats to protect for astronaut communications, alarm audibility, and habitability, and to reduce astronauts' risk for sleep disturbance, and hear-ing loss. But this is not an easy task, given the various design trade-offs, and it has been difficult, historically, to achieve. Over time it has been found that successful control of spacecraft acoustic levels is achieved by levying firm requirements at the system-level, using a systems engineering approach for design and development, and then validating these requirements with acoustic testing. In the systems engineering method, the system-level requirements must be flowed down to sub-systems and component noise sources, using acoustic analysis and acoustic modelling to develop allocated requirements for the sub-systems and components. Noise controls must also be developed, tested, and implemented so the sub-systems and components can achieve their allocated limits. It is also important to have management support for acoustics efforts to maintain their priority against the various trade-offs, including mass, volume, power, cost, and schedule. In this extended abstract and companion presentation, the requirements, approach, and results for controlling acoustic levels in most US spacecraft since Apollo will be briefly discussed. The approach for controlling acoustic levels in the future US space vehicle, Orion Multipurpose Crew Vehicle (MPCV), will also be briefly discussed. These discussions will be limited to the control of continuous noise inside the space vehicles. Other types of noise, such as launch, landing, and abort noise, intermittent noise, Extra-Vehicular Activity (EVA) noise, emergency operations/off-nominal noise, noise exposure, and impulse noise are important, but will not be discussed because of time limitations.

  14. Auto-identification of engine fault acoustic signal through inverse trigonometric instantaneous frequency analysis

    National Research Council Canada - National Science Library

    Ning, Dayong; Hou, Jiaoyi; Gong, Yongjun; Zhang, Zengmeng; Sun, Changle


    .... In this study, an instantaneous frequency analysis method was proposed. A new time–frequency model was constructed using a fixed amplitude and a variable cycle sine function to fit adjacent points gradually from a time domain signal...

  15. Shape optimization: Good looks and acoustics too! (United States)

    D'Antonio, Peter; Cox, Trevor J.; Haas, Steve


    One of the challenges in the architectural acoustic design of museums and other public spaces is to develop contemporary scattering surfaces that complement contemporary architecture in the way that statuary, coffered ceilings, columns, and relief ornamentation complemented classic architecture. Often acoustic surfaces satisfy the acoustics, but may or may not satisfy the aesthetics. One approach that has been successful employs a combination of boundary element and multidimensional optimization techniques. The architect supplies the desired shape motif and the acoustician supplies the acoustical performance requirements. The optimization program then provides an Arcousthetic surface, which simultaneously satisfies the architecture, the acoustics, and the aesthetics. The program can be used with diffusive or diffsorptive surfaces. Photos of installations using these acoustic tools and a description of the design of the National Museum of the American Indian will also be presented to illustrate the usefulness of these devices and their impact on architectural acoustics.

  16. Handbook of Signal Processing in Acoustics

    CERN Document Server

    Havelock, David; Vorländer, Michael


    The Handbook of Signal Processing in Acoustics presents signal processing as it is practiced in the field of acoustics. The Handbook is organized by areas of acoustics, with recognized leaders coordinating the self-contained chapters of each section. It brings together a wide range of perspectives from over 100 authors to reveal the interdisciplinary nature of signal processing in acoustics. Success in acoustic applications often requires juggling both the acoustic and the signal processing parameters of the problem. This handbook brings the key issues from both into perspective and is complementary to other reference material on the two subjects. It is a unique resource for experts and practitioners alike to find new ideas and techniques within the diversity of signal processing in acoustics.

  17. Spatial analysis and auralization of room acoustics using a tetrahedral microphone. (United States)

    Amengual Garí, Sebastià V; Lachenmayr, Winfried; Mommertz, Eckard


    A compact tetrahedral microphone array is used to measure several controlled sound fields and compare the analysis of spatial room impulse responses with two methods: spatial decomposition method (SDM) and IRIS, a commercial system based on sound intensity vector analysis. Results suggest that the spatial accuracy of both methods is similar and in most cases the error is comparable to the localization uncertainty of human listeners. Furthermore, a listening test is conducted comparing three 3D-sound fields and their SDM auralizations. Results suggest that the similarity of the auralized and original sound fields depends on the target room and stimulus.

  18. Acoustic Neuroma Association (United States)

    ... EVENTS DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts What is acoustic neuroma? Diagnosing ... Brain Freeze ? READ MORE Read More What is acoustic neuroma? Identifying an AN Learn More Get Info ...

  19. Analysis of the effect of impact of near-wall acoustic bubble collapse micro-jet on Al 1060. (United States)

    Ye, Linzheng; Zhu, Xijing


    The bubble collapse near a wall will generate strong micro-jet in a liquid environment under ultrasonic field. To explore the effect of the impact of near-wall acoustic bubble collapse micro-jet on an aluminum 1060 sheet, the cavitation threshold formula and micro-jet velocity formula were first proposed. Then the Johnson-Cook rate correlation material constitutive model was considered, and a three-dimensional fluid-solid coupling model of micro-jet impact on a wall was established and analyzed. Finally, to validate the model, ultrasonic cavitation test and inversion analysis based on the theory of spherical indentation test were conducted. The results show that cavitation occurs significantly in the liquid under ultrasonic field, as the applied ultrasonic pressure amplitude is much larger than liquid cavitation threshold. Micro pits appear on the material surface under the impact of micro-jet. Pit depth is determined by both micro-jet velocity and micro-jet diameter, and increases with their increase. Pit diameter is mainly related to the micro-jet diameter and dp/dj≈0.95-1.2, while pit's diameter-to-depth ratio is mainly negatively correlated with the micro-jet velocity. Wall pressure distribution is mostly symmetric and its maximum appears on the edge of micro-jet impingement. Obviously, the greater the micro-jet velocity is, the greater the wall pressure is. Micro pits formed after the impact of micro-jet on aluminum 1060 surface were assessed by ultrasonic cavitation test. Inversion analysis results indicate that equivalent stress, equivalent strain of the pit and impact strength, and velocity of the micro-jet are closely related with pit's diameter-to-depth ratio. For the pit's diameter-to-depth ratio of 16-68, the corresponding micro-jet velocity calculated is 310-370m/s. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Time-Frequency Feature Representation Using Multi-Resolution Texture Analysis and Acoustic Activity Detector for Real-Life Speech Emotion Recognition

    Directory of Open Access Journals (Sweden)

    Kun-Ching Wang


    Full Text Available The classification of emotional speech is mostly considered in speech-related research on human-computer interaction (HCI. In this paper, the purpose is to present a novel feature extraction based on multi-resolutions texture image information (MRTII. The MRTII feature set is derived from multi-resolution texture analysis for characterization and classification of different emotions in a speech signal. The motivation is that we have to consider emotions have different intensity values in different frequency bands. In terms of human visual perceptual, the texture property on multi-resolution of emotional speech spectrogram should be a good feature set for emotion classification in speech. Furthermore, the multi-resolution analysis on texture can give a clearer discrimination between each emotion than uniform-resolution analysis on texture. In order to provide high accuracy of emotional discrimination especially in real-life, an acoustic activity detection (AAD algorithm must be applied into the MRTII-based feature extraction. Considering the presence of many blended emotions in real life, in this paper make use of two corpora of naturally-occurring dialogs recorded in real-life call centers. Compared with the traditional Mel-scale Frequency Cepstral Coefficients (MFCC and the state-of-the-art features, the MRTII features also can improve the correct classification rates of proposed systems among different language databases. Experimental results show that the proposed MRTII-based feature information inspired by human visual perception of the spectrogram image can provide significant classification for real-life emotional recognition in speech.

  1. Using Principal Component and Tidal Analysis as a Quality Metric for Detecting Systematic Heading Uncertainty in Long-Term Acoustic Doppler Current Profiler Data (United States)

    Morley, M. G.; Mihaly, S. F.; Dewey, R. K.; Jeffries, M. A.


    Ocean Networks Canada (ONC) operates the NEPTUNE and VENUS cabled ocean observatories to collect data on physical, chemical, biological, and geological ocean conditions over multi-year time periods. Researchers can download real-time and historical data from a large variety of instruments to study complex earth and ocean processes from their home laboratories. Ensuring that the users are receiving the most accurate data is a high priority at ONC, requiring quality assurance and quality control (QAQC) procedures to be developed for all data types. While some data types have relatively straightforward QAQC tests, such as scalar data range limits that are based on expected observed values or measurement limits of the instrument, for other data types the QAQC tests are more comprehensive. Long time series of ocean currents from Acoustic Doppler Current Profilers (ADCP), stitched together from multiple deployments over many years is one such data type where systematic data biases are more difficult to identify and correct. Data specialists at ONC are working to quantify systematic compass heading uncertainty in long-term ADCP records at each of the major study sites using the internal compass, remotely operated vehicle bearings, and more analytical tools such as principal component analysis (PCA) to estimate the optimal instrument alignments. In addition to using PCA, some work has been done to estimate the main components of the current at each site using tidal harmonic analysis. This paper describes the key challenges and presents preliminary PCA and tidal analysis approaches used by ONC to improve long-term observatory current measurements.

  2. Spectral identification of sperm whales from Littoral Acoustic Demonstration Center passive acoustic recordings (United States)

    Sidorovskaia, Natalia A.; Richard, Blake; Ioup, George E.; Ioup, Juliette W.


    The Littoral Acoustic Demonstration Center (LADC) made a series of passive broadband acoustic recordings in the Gulf of Mexico and Ligurian Sea to study noise and marine mammal phonations. The collected data contain a large amount of various types of sperm whale phonations, such as isolated clicks and communication codas. It was previously reported that the spectrograms of the extracted clicks and codas contain well-defined null patterns that seem to be unique for individuals. The null pattern is formed due to individual features of the sound production organs of an animal. These observations motivated the present studies of adapting human speech identification techniques for deep-diving marine mammal phonations. A three-state trained hidden Markov model (HMM) was used with the phonation spectra of sperm whales. The HHM-algorithm gave 75% accuracy in identifying individuals when it had been initially tested for the acoustic data set correlated with visual observations of sperm whales. A comparison of the identification accuracy based on null-pattern similarity analysis and the HMM-algorithm is presented. The results can establish the foundation for developing an acoustic identification database for sperm whales and possibly other deep-diving marine mammals that would be difficult to observe visually. [Research supported by ONR.

  3. Acoustic Sensors for Air and Surface Navigation Applications. (United States)

    Kapoor, Rohan; Ramasamy, Subramanian; Gardi, Alessandro; Schyndel, Ron Van; Sabatini, Roberto


    This paper presents the state-of-the-art and reviews the state-of-research of acoustic sensors used for a variety of navigation and guidance applications on air and surface vehicles. In particular, this paper focuses on echolocation, which is widely utilized in nature by certain mammals (e.g., cetaceans and bats). Although acoustic sensors have been extensively adopted in various engineering applications, their use in navigation and guidance systems is yet to be fully exploited. This technology has clear potential for applications in air and surface navigation/guidance for Intelligent Transport Systems (ITS), especially considering air and surface operations indoors and in other environments where satellite positioning is not available. Propagation of sound in the atmosphere is discussed in detail, with all potential attenuation sources taken into account. The errors introduced in echolocation measurements due to Doppler, multipath and atmospheric effects are discussed, and an uncertainty analysis method is presented for ranging error budget prediction in acoustic navigation applications. Considering the design challenges associated with monostatic and multi-static sensor implementations and looking at the performance predictions for different possible configurations, acoustic sensors show clear promises in navigation, proximity sensing, as well as obstacle detection and tracking. The integration of acoustic sensors in multi-sensor navigation systems is also considered towards the end of the paper and a low Size, Weight and Power, and Cost (SWaP-C) sensor integration architecture is presented for possible introduction in air and surface navigation systems.

  4. Spectrum of the seismic-electromagnetic and acoustic waves caused by seismic and volcano activity

    Directory of Open Access Journals (Sweden)

    S. Koshevaya


    Full Text Available Modeling of the spectrum of the seismo-electromagnetic and acoustic waves, caused by seismic and volcanic activity, has been done. This spectrum includes the Electromagnetic Emission (EME, due to fracturing piezoelectrics in rocks and the Acoustic Emission (AE, caused by the excitation and the nonlinear passage of acoustic waves through the Earth's crust, the atmosphere, and the ionosphere. The investigated mechanism of the EME uses the model of fracturing and the crack motion. For its analysis, we consider a piezoelectric crystal under mechanical stresses, which cause the uniform crack motion, and, consequently, in the vicinity of the moving crack also cause non-stationary polarization currents. A possible spectrum of EME has been estimated. The underground fractures produce Very Low (VLF and Extremely Low Frequency (ELF acoustic waves, while the acoustic waves at higher frequencies present high losses and, on the Earth's surface, they are quite small and are not registered. The VLF acoustic wave is subject to nonlinearity under passage through the lithosphere that leads to the generation of higher harmonics and also frequency down-conversion, namely, increasing the ELF acoustic component on the Earth's surface. In turn, a nonlinear propagation of ELF acoustic wave in the atmosphere and the ionosphere leads to emerging the ultra low frequency (ULF acousto-gravity waves in the ionosphere and possible local excitation of plasma waves.

  5. Acoustic and Shear-Wave Velocities in Hydrate-Bearing Sediments Offshore Southwestern Taiwan: Tomography, Converted Waves Analysis and Reverse-Time Migration of OBS Records

    Directory of Open Access Journals (Sweden)

    Philippe Schnurle


    Full Text Available A 2.5-D combined seismic reflection and refraction survey has been conducted in the accretionary complex offshore of southwestern Taiwan where BSRs (Bottom Simulating Reflectors are highly concentrated and geochemical signals for the presence of gas hydrate are strong. In this study, we perform velocity analysis of the 6 4-component OBS (Ocean-Bottom Seismometer records along the southernmost transect of this seismic experiment. We utilize 3 independent methods in order to accurately determine the acoustic and shear-wave velocities of the sediments: 1-D Root Mean Square (RMS analysis of the P-P and P-S reflected events on individual datumed components, 2-D inversion of the P-P and P-S reflected and refracted events along the in-line transect, and 3-D acoustic inversion of the first arrivals. The principal sources of bias in the determination of the velocities are the 3-dimentional nature of the topography and the complexity of the underlying structures. The three methods result in consistent velocity profiles. Rapid lateral and vertical variations of the velocities are observed. We then investigate the large scale gas hydrate content through rock physic modeling: at the vertical of each OBS, shear-waves velocities are utilized to estimate the water-filled porosities, and the acoustic velocities predicted for a set of gas hydrate, quartz and clay contents are compared to the observed profiles.

  6. Performance Analysis of High-Order Numerical Methods for Time-Dependent Acoustic Field Modeling

    KAUST Repository

    Moy, Pedro Henrique Rocha


    The discretization of time-dependent wave propagation is plagued with dispersion in which the wavefield is perceived to travel with an erroneous velocity. To remediate the problem, simulations are run on dense and computationally expensive grids yielding plausible approximate solutions. This work introduces an error analysis tool which can be used to obtain optimal simulation parameters that account for mesh size, orders of spatial and temporal discretizations, angles of propagation, temporal stability conditions (usually referred to as CFL conditions), and time of propagation. The classical criteria of 10-15 nodes per wavelength for second-order finite differences, and 4-5 nodes per wavelength for fourth-order spectral elements are shown to be unrealistic and overly-optimistic simulation parameters for different propagation times. This work analyzes finite differences, spectral elements, optimally-blended spectral elements, and isogeometric analysis.

  7. Inharmonicity Analysis: A Novel Physical Method for Acoustic Screening of Dysphonia (United States)

    Matteson, Sam; Lu, Fang-Ling


    In the United States 6.8% of men, women, and children report current voice problems and approximately 29% will report some problems during their lifetime. Often this dysphonia is due to pathologies of the vocal folds. The authors (a physicist and a speech pathologist) describe an interdisciplinary approach that shows promise of detecting physiological abnormalities of the vocal folds from an analysis of the Fourier spectrum of spoken ``tokens.'' The underlying principle maintains that the normal human vocal fold is a linear oscillator that emits overtones that are very nearly precise integral values of the fundamental. Physiological problems of the vocal folds, however, introduce mechanical non-linearities that manifest themselves as frequency deviations from the ideal harmonic (that is, integral) values. The authors quantify this inharmonicity, describing and illustrating how one can obtain and analyze such data. They outline, as well, a proposed program to assess the clinical sensitivity and significance of the analysis discussed in this work.

  8. Coupled Finite Element and Cellular Automata Methods for Analysis of Composite Structures in an Acoustic Domain (United States)


    core crushing, skin wrinkling , and general buckling . Debonding is the separation of the skin material from the core and delamination usually refers...or plate, for example, can be modeled with relative fidelity with just a few elements; while the analysis of air-flow over a golf ball would require...elements of a size comparable to the ball’s dimples, which could lead to an exorbitant computational cost for a domain on the order of three ball

  9. Dose response severity functions for acoustic disturbance in cetaceans using recurrent event survival analysis

    NARCIS (Netherlands)

    Harris, C.M.; Sadykova, D.; DeRuiter, S.L.; Tyack, P.L.; Miller, P.J.O.; Kvadsheim, P.H.; Lam, F.P.A.; Thomas, L.


    Behavioral response studies (BRSs) aim to enhance our understanding of the behavior changes made by animals in response to specific exposure levels of different stimuli, often presented in an increasing dosage. Here, we focus on BRSs that aim to understand behavioral responses of free-ranging whales

  10. Analysis Results for ARRA Projects: Enabling Fuel Cell Market Transformation (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, J.; Wipke, K.; Sprik, S.; Ramsden, T.; Ainscough, C.; Saur, G.


    This presentation discusses analysis results for American Recovery and Reinvestment Act early market fuel cell deployments and describes the objective of the project and its relevance to the Department of Energy Hydrogen and Fuel Cells Program; NREL's analysis approach; technical accomplishments including publication of a fourth set of composite data products; and collaborations and future work.

  11. Android application and REST server system for quasar spectrum presentation and analysis (United States)

    Wasiewicz, P.; Pietralik, K.; Hryniewicz, K.


    This paper describes the implementation of a system consisting of a mobile application and RESTful architecture server intended for the analysis and presentation of quasars' spectrum. It also depicts the quasar's characteristics and significance to the scientific community, the source for acquiring astronomical objects' spectral data, used software solutions as well as presents the aspect of Cloud Computing and various possible deployment configurations.

  12. Topology optimization of acoustic-structure interaction problems using a mixed finite element formulation

    DEFF Research Database (Denmark)

    Yoon, Gil Ho; Jensen, Jens Stissing; Sigmund, Ole


    The paper presents a gradient-based topology optimization formulation that allows to solve acoustic-structure (vibro-acoustic) interaction problems without explicit boundary interface representation. In acoustic-structure interaction problems, the pressure and displacement fields are governed...

  13. On acoustic emission for damage detection and failure prediction in fiber reinforced polymer rods using pattern recognition analysis (United States)

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


    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.

  14. Analysis of Acoustic Modeling and Sound Propagation in Aircraft Noise Prediction (United States)

    Plotkin, Kenneth J.; Shepherd, Kevin P. (Technical Monitor)


    An analysis has been performed of measured and predicted aircraft noise levels around Denver International Airport. A detailed examination was made of 90 straight-out departures that yielded good measurements on multiple monitors. Predictions were made with INM 5, INM 6 and the simulation model NMSIM. Predictions were consistently lower than measurements, less so for the simulation model than for the integrated models. Lateral directivity ("installation effect") patterns were seen which are consistent with other recent measurements. Atmospheric absorption was determined to be a significant factor in the underprediction. Calculations of atmospheric attenuation were made over a full year of upper air data at seven locations across the United States. It was found that temperature/humidity effects could cause variations of up to +/-4 dB, depending on season, for the sites examined. It was concluded that local temperature and humidity should be accounted for in aircraft noise modeling.

  15. Finite element analysis for the inhibition of electromagnetic acoustic testing (EMAT) Lamb waves multi-modes (United States)

    Liu, Suzhen; Zhang, Yanwei; Zhang, Chuang; Yang, Qingxin


    Lamb waves are widely used in nondestructive testing (NDT) and structural health monitoring (SHM) for its obvious advantages, such as good directionality, longer-range propagation and lower loss etc. However, it is difficult to analysis and to interpret the echo signals because of its multi-modes and dispersion. In this paper, the properties of single-mode Lamb waves which were excited by double EMAT were studied based on the principles of multi-modes and the characteristics of wave structure. Simulation results show that the double transducer excitation structure can stimulate single-mode Lamb waves and eliminate the extra modes, which are produced by modal conversion at ends of the specimen. The single-mode excitation of Lamb waves is beneficial to reduce the difficulty of signal processing and provide reliable information to locate the defect. The researches in this paper can be used as a theoretical basis to design double transducer excitation system.

  16. Visualizing acoustical beats with a smartphones

    CERN Document Server

    Giménez, Marcos H; Castro-Palacio, Juan C; Gómez-Tejedor, José A; Monsoriu, Juan A


    In this work, a new Physics laboratory experiment on Acoustics beats is presented. We have designed a simple experimental setup to study superposition of sound waves of slightly different frequencies (acoustic beat). The microphone of a smartphone is used to capture the sound waves emitted by two equidistant speakers from the mobile which are at the same time connected to two AC generators. The smartphone is used as a measuring instrument. By means of a simple and free AndroidTM application, the sound level (in dB) as a function of time is measured and exported to a .csv format file. Applying common graphing analysis and a fitting procedure, the frequency of the beat is obtained. The beat frequencies as obtained from the smartphone data are compared with the difference of the frequencies set at the AC generator. A very good agreement is obtained being the percentage discrepancies within 1 %.

  17. Underwater acoustic signatures of glacier calving (United States)

    Glowacki, O.; Deane, G. B.; Moskalik, M.; Blondel, Ph.; Tegowski, J.; Blaszczyk, M.


    Climate-driven ice-water interactions in the contact zone between marine-terminating glaciers and the ocean surface show a dynamic and complex nature. Tidewater glaciers lose volume through the poorly understood process of calving. A detailed description of the mechanisms controlling the course of calving is essential for the reliable estimation and prediction of mass loss from glaciers. Here we present the potential of hydroacoustic methods to investigate different modes of ice detachments. High-frequency underwater ambient noise recordings are combined with synchronized, high-resolution, time-lapse photography of the Hans Glacier cliff in Hornsund Fjord, Spitsbergen, to identify three types of calving events: typical subaerial, sliding subaerial, and submarine. A quantitative analysis of the data reveals a robust correlation between ice impact energy and acoustic emission at frequencies below 200 Hz for subaerial calving. We suggest that relatively inexpensive acoustic methods can be successfully used to provide quantitative descriptions of the various calving types.

  18. A programmable nonlinear acoustic metamaterial (United States)

    Yang, Tianzhi; Song, Zhi-Guang; Clerkin, Eoin; Zhang, Ye-Wei; Sun, Jia-He; Su, Yi-Shu; Chen, Li-Qun; Hagedorn, Peter


    Acoustic metamaterials with specifically designed lattices can manipulate acoustic/elastic waves in unprecedented ways. Whereas there are many studies that focus on passive linear lattice, with non-reconfigurable structures. In this letter, we present the design, theory and experimental demonstration of an active nonlinear acoustic metamaterial, the dynamic properties of which can be modified instantaneously with reversibility. By incorporating active and nonlinear elements in a single unit cell, a real-time tunability and switchability of the band gap is achieved. In addition, we demonstrate a dynamic "editing" capability for shaping transmission spectra, which can be used to create the desired band gap and resonance. This feature is impossible to achieve in passive metamaterials. These advantages demonstrate the versatility of the proposed device, paving the way toward smart acoustic devices, such as logic elements, diode and transistor.

  19. Analysis of forward scattering of an acoustical zeroth-order Bessel beam from rigid complicated (aspherical) structures (United States)

    Li, Wei; Chai, Yingbin; Gong, Zhixiong; Marston, Philip L.


    The forward scattering from rigid spheroids and endcapped cylinders with finite length (even with a large aspect ratio) immersed in a non-viscous fluid under the illumination of an idealized zeroth-order acoustical Bessel beam (ABB) with arbitrary angles of incidence is calculated and analyzed in the implementation of the T-matrix method (TTM). Based on the present method, the incident coefficients of expansion for the incident ABB are derived and simplifying methods are proposed for the numerical accuracy and computational efficiency according to the geometrical symmetries. A home-made MATLAB software package is constructed accordingly, and then verified and validated for the ABB scattering from rigid aspherical obstacles. Several numerical examples are computed for the forward scattering from both rigid spheroids and finite cylinder, with particular emphasis on the aspect ratios, the half-cone angles of ABBs, the incident angles and the dimensionless frequencies. The rectangular patterns of target strength in the (β, θs) domain (where β is the half-cone angle of the ABB and θs is the scattered polar angle) and local/total forward scattering versus dimensionless frequency are exhibited, which could provide new insights into the physical mechanisms of Bessel beam scattering by rigid spheroids and finite cylinders. The ray diagrams in geometrical models for the scattering in the forward half-space and the optical cross-section theorem help to interpret the scattering mechanisms of ABBs. This research work may provide an alternative for the partial wave series solution under certain circumstances interacting with ABBs for complicated obstacles and benefit some related works in optics and electromagnetics.

  20. Acoustic emission and acousto-ultrasonic signature analysis of failure mechanisms in carbon fiber reinforced polymer materials (United States)

    Carey, Shawn Allen

    Fiber reinforced polymer composite materials, particularly carbon (CFRPs), are being used for primary structural applications, particularly in the aerospace and naval industries. Advantages of CFRP materials, compared to traditional materials such as steel and aluminum, include: light weight, high strength to weight ratio, corrosion resistance, and long life expectancy. A concern with CFRPs is that despite quality control during fabrication, the material can contain many hidden internal flaws. These flaws in combination with unseen damage due to fatigue and low velocity impact have led to catastrophic failure of structures and components. Therefore a large amount of research has been conducted regarding nondestructive testing (NDT) and structural health monitoring (SHM) of CFRP materials. The principal objective of this research program was to develop methods to characterize failure mechanisms in CFRP materials used by the U.S. Army using acoustic emission (AE) and/or acousto-ultrasonic (AU) data. Failure mechanisms addressed include fiber breakage, matrix cracking, and delamination due to shear between layers. CFRP specimens were fabricated and tested in uniaxial tension to obtain AE and AU data. The specimens were designed with carbon fibers in different orientations to produce the different failure mechanisms. Some specimens were impacted with a blunt indenter prior to testing to simulate low-velocity impact. A signature analysis program was developed to characterize the AE data based on data examination using visual pattern recognition techniques. It was determined that it was important to characterize the AE event , using the location of the event as a parameter, rather than just the AE hit (signal recorded by an AE sensor). A back propagation neural network was also trained based on the results of the signature analysis program. Damage observed on the specimens visually with the aid of a scanning electron microscope agreed with the damage type assigned by the

  1. Blind Separation of Acoustic Signals Combining SIMO-Model-Based Independent Component Analysis and Binary Masking

    Directory of Open Access Journals (Sweden)

    Hiekata Takashi


    Full Text Available A new two-stage blind source separation (BSS method for convolutive mixtures of speech is proposed, in which a single-input multiple-output (SIMO-model-based independent component analysis (ICA and a new SIMO-model-based binary masking are combined. SIMO-model-based ICA enables us to separate the mixed signals, not into monaural source signals but into SIMO-model-based signals from independent sources in their original form at the microphones. Thus, the separated signals of SIMO-model-based ICA can maintain the spatial qualities of each sound source. Owing to this attractive property, our novel SIMO-model-based binary masking can be applied to efficiently remove the residual interference components after SIMO-model-based ICA. The experimental results reveal that the separation performance can be considerably improved by the proposed method compared with that achieved by conventional BSS methods. In addition, the real-time implementation of the proposed BSS is illustrated.

  2. Enhanced ion acoustic fluctuations and ion outflows

    Directory of Open Access Journals (Sweden)

    F. R. E. Forme


    Full Text Available A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acoustic lines. This spectral asymmetry and the intensity of the received signal cannot be resolved by the standard analysis procedure and often causes its failure. As a result, and in spite of a very clear spectral signature, the analysis is unable to fit the plasma parameters inside the regions of ion acoustic turbulence. We present European Incoherent Scatter radar (EISCAT observations of large ion outflows associated with the simultaneous occurrence of enhanced ion acoustic echoes. The ion fluxes can reach 1014 m-2 s-1 at 800 km altitude. From the very clear spectral signatures of these echoes, a method is presented to extract estimates of the electron temperature and the ion drift within the turbulent regions. It is shown that the electron gas is strongly heated up to 11 000 K. Also electron temperature gradients of about 0.02 K/m exist. Finally, the estimates of the electron temperature and of the ion drift are used to study the possible implications for the plasma transport inside turbulent regions. It is shown that strong electron temperature gradients cause enhancement of the ambipolar electric field and can account for the observed ion outflows.Key words. Ionosphere (auroral ionosphere; ionosphere · magnetosphere interactions; plasma waves and instabilities.

  3. Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators through Laser Acoustic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ken Telschow; John D. Larson III


    Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (~900 MHz) in an AlN thin film resonator. Plate wave modeling, taking account of material crystalline orientation, elastic and piezoelectric properties and overlayer metallic films, will be discussed in relation to direct image measurements.

  4. Analysis and presentation of experimental results with examples, problems and programs

    CERN Document Server

    Christodoulides, Costas


    This book is intended as a guide to the analysis and presentation of experimental results. It develops various techniques for the numerical processing of experimental data, using basic statistical methods and the theory of errors. After presenting basic theoretical concepts, the book describes the methods by which the results can be presented, both numerically and graphically. The book is divided into three parts, of roughly equal length, addressing the theory, the analysis of data, and the presentation of results. Examples are given and problems are solved using the Excel, Origin, Python and R software packages. In addition, programs in all four languages are made available to readers, allowing them to use them in analyzing and presenting the results of their own experiments. Subjects are treated at a level appropriate for undergraduate students in the natural sciences, but this book should also appeal to anyone whose work involves dealing with experimental results.

  5. How Native Do They Sound? An Acoustic Analysis of the Spanish Vowels of Elementary Spanish Immersion Students (United States)

    Menke, Mandy R.


    Language immersion students' lexical, syntactic, and pragmatic competencies are well documented, yet their phonological skill has remained relatively unexplored. This study investigates the Spanish vowel productions of a cross-sectional sample of 35 one-way Spanish immersion students. Learner productions were analyzed acoustically and compared to…

  6. Acoustic characteristics of Danish infant directed speech

    DEFF Research Database (Denmark)

    Bohn, Ocke-Schwen


    Danish presents several challenges for language learners, such as a very densely packed upper portion of the acoustic vowel space, and a sibilant contrast that is acoustically less distinct than in e.g. English. The present study examined whether Danish caregivers enhance Danish contrasts when sp......'s receptive vocabulary knowledge....

  7. Present status and perspective of radiochemical analysis of radionuclides in Nordic countries

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Olsson, Mattias; Togneri, Laura


    Radiochemical analysis plays a critical role in the determination of pure beta and alpha emitting radionuclides for environmental monitoring, radioecology, decommissioning, nuclear forensics and geological dating. A remarkable development on radiochemical analysis has been achieved in the past...... decades to meet the increased requirement. In the recent years, mass spectrometric techniques have been considerably improved and are widely employed for measurement of radionuclides. Analytical methods for rapid, automated and simultaneous determination of radionuclides have been extensively developed...... for emergency analysis. In Nordic countries, many laboratories are involved in the determination of radionuclides for various purposes, and a series of radiochemical analytical methods have been developed and applied. This article presents the present status and progress on radiochemical analysis...

  8. Opto-acoustic cell permeation

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S R; Heredia, N


    Optically generated acoustic waves have been used to temporarily permeate biological cells. This technique may be useful for enhancing transfection of DNA into cells or enhancing the absorption of locally delivered drugs. A diode-pumped frequency-doubled Nd:YAG laser operating at kHz repetition rates was used to produce a series of acoustic pulses. An acoustic wave was formed via thermoelastic expansion by depositing laser radiation into an absorbing dye. Generated pressures were measured with a PVDF hydrophone. The acoustic waves were transmitted to cultured and plated cells. The cell media contained a selection of normally- impermeable fluorescent-labeled dextran dyes. Following treatment with the opto-acoustic technique, cellular incorporation of dyes, up to 40,000 Molecular Weight, was noted. Control cells that did not receive opto-acoustic treatment had unremarkable dye incorporation. Uptake of dye was quantified via fluorescent microscopic analysis. Trypan Blue membrane exclusion assays and fluorescent labeling assays confirmed the vitality of cells following treatment. This method of enhanced drug delivery has the potential to dramatically reduce required drug dosages and associated side effects and enable revolutionary therapies.

  9. Acoustic transducer (United States)

    Drumheller, Douglas S.


    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  10. Use of acoustic vortices in acoustic levitation

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller


    Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without...

  11. Acoustic-mean flow interaction in solid rocket motors using Navier-Stokes equations (United States)

    Vuillot, F.; Avalon, G.


    The presented numerical solution of laminar, two-dimensional, compressible and unsteady Navier-Stokes equations is aimed at a complete description of acoustic boundary layers that develop above a burning propellant. Such acoustic boundary layers are responsible for the so-called flow turning losses and also govern the local unsteady flow conditions that are seen by the burning propellant and to which it finally responds. In those respects, a complete understanding of such acoustic boundary layers is essential to improve existing solid rocket stability prediction codes. The full numerical solution of the Navier-Stokes equations permits to naturally incorporate into the analysis all the features of two-dimensional rocket chamber mean flow field. After a standing wave pattern is established through forcing at a given frequency, a special Fourier treatment is used to put the numerical results in a form directly comparable to available linear acoustic data. The presented results indicate that the acoustic boundary layer is substantially thinner than predicted by simplified models. Moreover, its acoustic admittance is found to significantly vary along the chamber, a result that is of major importance to stability predictions. Finally, the acoustic field is found to be rotational over a significant volume of the chamber, leading to a volume flow turning loss, rather than to a pure surface effect as usually assumed.

  12. Systematic design of acoustic devices by topology optimization

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Sigmund, Ole


    We present a method to design acoustic devices with topology optimization. The general algorithm is exemplified by the design of a reflection chamber that minimizes the transmission of acoustic waves in a specified frequency range....

  13. Hidden acoustic information revealed by intentional nonlinearity (United States)

    Dowling, David R.


    Acoustic waves are omnipresent in modern life and are well described by the linearized equations of fluid dynamics. Once generated, acoustic waves carry and collect information about their source and the environment through which they propagate, respectively, and this information may be retrieved by analyzing recordings of these waves. Because of this, acoustics is the primary means for observation, surveillance, reconnaissance, and remote sensing in otherwise opaque environments, such as the Earth's oceans and crust, and the interior of the human body. For such information-retrieval tasks, acoustic fields are nearly always interrogated within their recorded frequency range or bandwidth. However, this frequency-range restriction is not general; acoustic fields may also carry (hidden) information at frequencies outside their bandwidth. Although such a claim may seem counter intuitive, hidden acoustic-field information can be revealed by re-introducing a marquee trait of fluid dynamics: nonlinearity. In particular, an intentional quadratic nonlinearity - a form of intra-signal heterodyning - can be used to obtain acoustic field information at frequencies outside a recorded acoustic field's bandwidth. This quadratic nonlinearity enables a variety of acoustic remote sensing applications that were long thought to be impossible. In particular, it allows the detrimental effects of sparse recordings and random scattering to be suppressed when the original acoustic field has sufficient bandwidth. In this presentation, the topic is developed heuristically, with a just brief exposition of the relevant mathematics. Hidden acoustic field information is then revealed from simulated and measured acoustic fields in simple and complicated acoustic environments involving frequencies from a few Hertz to more than 100 kHz, and propagation distances from tens of centimeters to hundreds of kilometers. Sponsored by ONR, NAVSEA, and NSF.

  14. Acoustics Research of Propulsion Systems (United States)

    Gao, Ximing; Houston, Janice


    The liftoff phase induces high acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are used in the prediction of the internal vibration responses of the vehicle and components. Present liftoff vehicle acoustic environment prediction methods utilize stationary data from previously conducted hold-down tests to generate 1/3 octave band Sound Pressure Level (SPL) spectra. In an effort to update the accuracy and quality of liftoff acoustic loading predictions, non-stationary flight data from the Ares I-X were processed in PC-Signal in two flight phases: simulated hold-down and liftoff. In conjunction, the Prediction of Acoustic Vehicle Environments (PAVE) program was developed in MATLAB to allow for efficient predictions of sound pressure levels (SPLs) as a function of station number along the vehicle using semi-empirical methods. This consisted of generating the Dimensionless Spectrum Function (DSF) and Dimensionless Source Location (DSL) curves from the Ares I-X flight data. These are then used in the MATLAB program to generate the 1/3 octave band SPL spectra. Concluding results show major differences in SPLs between the hold-down test data and the processed Ares I-X flight data making the Ares I-X flight data more practical for future vehicle acoustic environment predictions.

  15. Electromagnetically generated acoustic determination of delamination (United States)

    Imaino, W.


    Previous work has demonstrated a technique for acoustically detecting localized delamination of metallized patterns on insulating substrates [W. Imaino, L. Crawforth, A. C. Munce, and A. Julaiana, in Proceedings of the IEEE Ultrasonics Symposium, edited by B. R. McAvoy (IEEE, New York, 1986), p. 1065]. Employing a high-spatial-resolution permeable electromagnetic acoustic transducer to preferentially excite the metallization, the acoustic coupling between the metal foil and substrate may be probed. Scanning, then, provides a map of delaminations. To extend and generalize these results, the detailed generation mechanism and acoustic response of the substrate has been studied. A computer program developed previously [W. Imaino, J. Acoust. Soc. Am. Suppl. 1 80, S7 (1986)] was used to model the acoustic source. In this investigation, a finite-element calculation is used to provide a more detailed description of the acoustic behavior of the delaminated plate. The effects of source size relative to defect dimensions and acoustic properties of the substrate have been studied. The determination of the localized coupling is complicated by structural resonances of the substrate, which make single frequency measurements unfavorable. However, the analysis shows that the spectral acoustic behavior provides an indication of metallization to substrate coupling. A signal-processing algorithm based on this analysis has been formulated and will be described.

  16. System approach to robust acoustic echo cancellation through semi-blind source separation based on independent component analysis (United States)

    Wada, Ted S.

    In this dissertation, we build a foundation for what we refer to as the system approach to signal enhancement as we focus on the acoustic echo cancellation (AEC) problem. Such a “system” perspective aims for the integration of individual components, or algorithms, into a cohesive unit for the benefit of the system as a whole to cope with real-world enhancement problems. The standard system identification approach by minimizing the mean square error (MSE) of a linear system is sensitive to distortions that greatly affect the quality of the identification result. Therefore, we begin by examining in detail the technique of using a noise-suppressing nonlinearity in the adaptive filter error feedback-loop of the LMS algorithm when there is an interference at the near end, where the source of distortion may be linear or nonlinear. We provide a thorough derivation and analysis of the error recovery nonlinearity (ERN) that “enhances” the filter estimation error prior to the adaptation to transform the corrupted error’s distribution into a desired one, or very close to it, in order to assist the linear adaptation process. We reveal important connections of the residual echo enhancement (REE) technique to other existing AEC and signal enhancement procedures, where the technique is well-founded in the information-theoretic sense and has strong ties to independent component analysis (ICA), which is the basis for blind source separation (BSS) that permits unsupervised adaptation in the presence of multiple interfering signals. Notably, the single-channel AEC problem can be viewed as a special case of semi-blind source separation (SBSS) where one of the source signals is partially known, i.e., the far-end microphone signal that generates the near-end acoustic echo. Indeed, SBSS optimized via ICA leads to the system combination of the LMS algorithm with the ERN that allows continuous and stable adaptation even during double talk. Next, we extend the system perspective

  17. Aero-acoustics of Drag Generating Swirling Exhaust Flows (United States)

    Shah, P. N.; Mobed, D.; Spakovszky, Z. S.; Brooks, T. F.; Humphreys, W. M. Jr.


    Aircraft on approach in high-drag and high-lift configuration create unsteady flow structures which inherently generate noise. For devices such as flaps, spoilers and the undercarriage there is a strong correlation between overall noise and drag such that, in the quest for quieter aircraft, one challenge is to generate drag at low noise levels. This paper presents a rigorous aero-acoustic assessment of a novel drag concept. The idea is that a swirling exhaust flow can yield a steady, and thus relatively quiet, streamwise vortex which is supported by a radial pressure gradient responsible for pressure drag. Flows with swirl are naturally limited by instabilities such as vortex breakdown. The paper presents a first aero-acoustic assessment of ram pressure driven swirling exhaust flows and their associated instabilities. The technical approach combines an in-depth aerodynamic analysis, plausibility arguments to qualitatively describe the nature of acoustic sources, and detailed, quantitative acoustic measurements using a medium aperture directional microphone array in combination with a previously established Deconvolution Approach for Mapping of Acoustic Sources (DAMAS). A model scale engine nacelle with stationary swirl vanes was designed and tested in the NASA Langley Quiet Flow Facility at a full-scale approach Mach number of 0.17. The analysis shows that the acoustic signature is comprised of quadrupole-type turbulent mixing noise of the swirling core flow and scattering noise from vane boundary layers and turbulent eddies of the burst vortex structure near sharp edges. The exposed edges are the nacelle and pylon trailing edge and the centerbody supporting the vanes. For the highest stable swirl angle setting a nacelle area based drag coefficient of 0.8 was achieved with a full-scale Overall Sound Pressure Level (OASPL) of about 40dBA at the ICAO approach certification point.

  18. Acoustic levitation of a large solid sphere

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marco A. B., E-mail: [Institute of Physics, University of São Paulo, São Paulo 05508-090 (Brazil); Bernassau, Anne L. [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Adamowski, Julio C. [Department of Mechatronics and Mechanical Systems Engineering, Escola Politécnica, University of São Paulo, São Paulo 05508-030 (Brazil)


    We demonstrate that acoustic levitation can levitate spherical objects much larger than the acoustic wavelength in air. The acoustic levitation of an expanded polystyrene sphere of 50 mm in diameter, corresponding to 3.6 times the wavelength, is achieved by using three 25 kHz ultrasonic transducers arranged in a tripod fashion. In this configuration, a standing wave is created between the transducers and the sphere. The axial acoustic radiation force generated by each transducer on the sphere was modeled numerically as a function of the distance between the sphere and the transducer. The theoretical acoustic radiation force was verified experimentally in a setup consisting of an electronic scale and an ultrasonic transducer mounted on a motorized linear stage. The comparison between the numerical and experimental acoustic radiation forces presents a good agreement.

  19. When pacemakers fail: an analysis of clinical presentation and risk in 120 patients with failed devices. (United States)

    Nanthakumar, K; Dorian, P; Ham, M; Lam, P; Lau, C; Nishimura, S; Newman, D


    Although pacemaker recalls are common, the optimal mechanism for risk assessment and triage of patients at risk for sudden loss of device system function is unknown. A retrospective chart review of 120 patients with factory proven failed devices was performed. Logistic regression analysis was used to determine clinical correlates of emergency room versus outpatient clinic presentation at time of device failure. Twenty-two patients (18%) presented to emergency and 98 (82%) to clinic. Sixty-three devices had no device output at the time of presentation. Multivariate logistic regression analysis revealed that antiarrhythmic drug use (odds ratio: 7.4, 95% CI: 2.0-28.0), atrioventricular nodal disease as an indication for pacing (odds ratio: 2.8, 95% CI: 1.2-3.0), and female gender (odds ratio: 2.2, 95% CI: 1.0-4.5) were the only significant correlates of emergency room presentations. Pacemaker dependency (escape heart rate < 40 beats/min) did not correlate with location of presentation even though no device output at the time of presentation was associated with emergency room presentation (odds ratio: 2.5, 95% CI: 1.1-5.8). Neither the presence of structural heart disease nor symptoms at the time of device implantation (syncope or presyncope) were correlated with location of presentation upon unexpected device failure. Although there were no deaths in the 120 failed devices studied, there were 26 deaths in the total group of 227 patients with recalled devices that could not be studied. Antiarrhythmic drug use, electrocardiographic pacing indication, and female gender may be more sensitive predictors of emergency room presentation and significant symptoms in the event of unanticipated pacemaker failure. The inability of any retrospective analysis to accurately assess mortality in the setting of pacemaker system failure underscores the need for prospective databases in recall situations.

  20. Acoustic analysis of shock production by very high-altitude meteors—I: infrasonic observations, dynamics and luminosity (United States)

    Brown, P. G.; Edwards, W. N.; Revelle, D. O.; Spurny, P.


    Four very high-velocity and high-altitude meteors (a Leonid, two Perseids and a high-speed sporadic fireball) have been unambiguously detected at the ground both optically using precision all-sky cameras and acoustically via infrasound and seismic signals. Infrasound arriving from altitudes of over 100 km is not very common, but has been previously observed for re-entering spacecraft. This, however, is the first reported detection of such high-altitude infrasound unambiguously from meteors to our knowledge. These fragile meteoroids were found to generate acoustic waves at source heights ranging from 80 to 110 km, with most acoustic energy being generated near the lowest heights. Time residuals between observed acoustic onset and model predictions based on ray-tracing points along the photographically determined trajectories indicate that the upper winds given by the UK meteorological office (UKMO) model systematically produce lower residuals for first arrivals than those from the Naval Research Laboratory Horizontal Wind Model (HWM). Average source energies for three of the four events from acoustic data alone are found to be in the range of 2×108-9 J. One event, EN010803, had unusually favorable geometry for acoustic detection at the ground and therefore has the smallest photometric source energy (10-5 kt; 6×107 J) of any meteor detected infrasonically. When compared to the total optical radiation recorded by film, the results for the three events produce equivalent integral panchromatic luminous efficiencies of 3 7%, within a factor of two of the values proposed by Ceplecha and McCrosky [1976. Fireball end heights—a diagnostic for the structure of meteoric material. Journal of Geophysical Research 81, 6257 6275] for the velocity range (55 70 km s-1) appropriate to our events. Application of these findings to meteor showers in general suggest that the Geminid shower should be the most prolific producer of infrasound detectable meteors at the ground of all the

  1. Two Premises and One General Hypothesis for the Analysis of the Educational Present (United States)

    Aquino, Julio Groppa


    Contemporary research in the field of Foucauldian studies on education have pointed to a growing imbrication between educational practises and neoliberal ideas. The problematization of such scenario would lead to two premises, grounded on a general hypothesis for the analysis of the educational present. The first premise: nowadays, the educational…

  2. [The SWOT analysis and strategic considerations for the present medical devices' procurement]. (United States)

    Li, Bin; He, Meng-qiao; Cao, Jian-wen


    In this paper, the SWOT analysis method is used to find out the internal strength, weakness, exterior opportunities and threats of the present medical devices' procurements in hospitals and some strategic considerations are suggested as "one direction, two expansions, three changes and four countermeasures".

  3. Fast wideband acoustical holography. (United States)

    Hald, Jørgen


    Patch near-field acoustical holography methods like statistically optimized near-field acoustical holography and equivalent source method are limited to relatively low frequencies, where the average array-element spacing is less than half of the acoustic wavelength, while beamforming provides useful resolution only at medium-to-high frequencies. With adequate array design, both methods can be used with the same array. But for holography to provide good low-frequency resolution, a small measurement distance is needed, whereas beamforming requires a larger distance to limit sidelobe issues. The wideband holography method of the present paper was developed to overcome that practical conflict. Only a single measurement is needed at a relatively short distance and a single result is obtained covering the full frequency range. The method uses the principles of compressed sensing: A sparse sound field representation is assumed with a chosen set of basis functions, a measurement is taken with an irregular array, and the inverse problem is solved with a method that enforces sparsity in the coefficient vector. Instead of using regularization based on the 1-norm of the coefficient vector, an iterative solution procedure is used that promotes sparsity. The iterative method is shown to provide very similar results in most cases and to be computationally much more efficient.

  4. Introducing passive acoustic filter in acoustic based condition monitoring: Motor bike piston-bore fault identification (United States)

    Jena, D. P.; Panigrahi, S. N.


    Requirement of designing a sophisticated digital band-pass filter in acoustic based condition monitoring has been eliminated by introducing a passive acoustic filter in the present work. So far, no one has attempted to explore the possibility of implementing passive acoustic filters in acoustic based condition monitoring as a pre-conditioner. In order to enhance the acoustic based condition monitoring, a passive acoustic band-pass filter has been designed and deployed. Towards achieving an efficient band-pass acoustic filter, a generalized design methodology has been proposed to design and optimize the desired acoustic filter using multiple filter components in series. An appropriate objective function has been identified for genetic algorithm (GA) based optimization technique with multiple design constraints. In addition, the sturdiness of the proposed method has been demonstrated in designing a band-pass filter by using an n-branch Quincke tube, a high pass filter and multiple Helmholtz resonators. The performance of the designed acoustic band-pass filter has been shown by investigating the piston-bore defect of a motor-bike using engine noise signature. On the introducing a passive acoustic filter in acoustic based condition monitoring reveals the enhancement in machine learning based fault identification practice significantly. This is also a first attempt of its own kind.

  5. Extracting elastic properties of an atomically thin interfacial layer by time-domain analysis of femtosecond acoustics (United States)

    Chen, H.-Y.; Huang, Y.-R.; Shih, H.-Y.; Chen, M.-J.; Sheu, J.-K.; Sun, C.-K.


    Modern devices adopting denser designs and complex 3D structures have created much more interfaces than before, where atomically thin interfacial layers could form. However, fundamental information such as the elastic property of the interfacial layers is hard to measure. The elastic property of the interfacial layer is of great importance in both thermal management and nano-engineering of modern devices. Appropriate techniques to probe the elastic properties of interfacial layers as thin as only several atoms are thus critically needed. In this work, we demonstrated the feasibility of utilizing the time-resolved femtosecond acoustics technique to extract the elastic properties and mass density of a 1.85-nm-thick interfacial layer, with the aid of transmission electron microscopy. We believe that this femtosecond acoustics approach will provide a strategy to measure the absolute elastic properties of atomically thin interfacial layers.

  6. Present-day stress state analysis on the Big Island of Hawaíi, USA (United States)

    Pierdominici, Simona; Kueck, Jochem; Millett, John; Planke, Sverre; Jerram, Dougal A.; Haskins, Eric; Thomas, Donald


    We analyze and interpret the stress features from a c. 1.5 km deep fully cored borehole (PTA2) on the Big Island of Hawaíi within the Humúula saddle region, between the Mauna Kea and Mauna Loa volcanoes. The Big Island of Hawaii comprises the largest and youngest island of the Hawaiian-Emperor seamount chain and is volumetrically dominated by shield stage tholeiitic volcanic rocks. Mauna Kea is dormant whereas Mauna Loa is still active. There are also a series of normal faults on Mauna Loa's northern and western slopes, between its two major rift zones, that are believed to be the result of combined circumferential tension from the two rift zones and from added pressure due to the westward growth of the neighboring Kīlauea volcano. The PTA2 borehole was drilled in 2013 into lava dominated formation (Pahoehoe and Aā) as part of the Humúula Groundwater Research Project (HGPR) with the purpose of characterizing the groundwater resource potential in this area. In 2016 two downhole logging campaigns were performed by the Operational Support Group of the International Continental Scientific Drilling Program (ICDP) to acquire a set of geophysical data as part of the Volcanic Margin Petroleum Prospectivity (VMAPP) project. The main objective of the logging campaign was to obtain high quality wireline log data to enable a detailed core-log integration of the volcanic sequence and to improve understanding of the subsurface expression of volcanic rocks. We identify stress features (e.g. borehole breakouts) and volcanic structures (e.g. flow boundaries, vesicles and jointing) at depth using borehole images acquired with an ABI43 acoustic borehole televiewer. We analyzed and interpreted the stress indicators and compared their orientation with the regional stress pattern. We identified a set of stress indicators along the hole dominantly concentrated within the lower logged interval of the PTA2 borehole. Two primary horizontal stress indicators have been taken into account

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


    Stafford, Kathleen


    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...

  8. A spatiotemporal analysis of acoustic interactions between great reed warblers (Acrocephalus arundinaceus) using microphone arrays and robot audition software HARK. (United States)

    Suzuki, Reiji; Matsubayashi, Shiho; Saito, Fumiyuki; Murate, Tatsuyoshi; Masuda, Tomohisa; Yamamoto, Koichi; Kojima, Ryosuke; Nakadai, Kazuhiro; Okuno, Hiroshi G


    Acoustic interactions are important for understanding intra- and interspecific communication in songbird communities from the viewpoint of soundscape ecology. It has been suggested that birds may divide up sound space to increase communication efficiency in such a manner that they tend to avoid overlap with other birds when they sing. We are interested in clarifying the dynamics underlying the process as an example of complex systems based on short-term behavioral plasticity. However, it is very problematic to manually collect spatiotemporal patterns of acoustic events in natural habitats using data derived from a standard single-channel recording of several species singing simultaneously. Our purpose here was to investigate fine-scale spatiotemporal acoustic interactions of the great reed warbler. We surveyed spatial and temporal patterns of several vocalizing color-banded great reed warblers ( Acrocephalus arundinaceus ) using an open-source software for robot audition HARK (Honda Research Institute Japan Audition for Robots with Kyoto University) and three new 16-channel, stand-alone, and water-resistant microphone arrays, named DACHO spread out in the bird's habitat. We first show that our system estimated the location of two color-banded individuals' song posts with mean error distance of 5.5 ± 4.5 m from the location of observed song posts. We then evaluated the temporal localization accuracy of the songs by comparing the duration of localized songs around the song posts with those annotated by human observers, with an accuracy score of average 0.89 for one bird that stayed at one song post. We further found significant temporal overlap avoidance and an asymmetric relationship between songs of the two singing individuals, using transfer entropy. We believe that our system and analytical approach contribute to a better understanding of fine-scale acoustic interactions in time and space in bird communities.

  9. Physiological Acoustics (United States)

    Young, Eric D.

    The analysis of physiological sound in the peripheral auditory system solves three important problems. First, sound energy impinging on the head must be captured and presented to the transduction apparatus in the ear as a suitable mechanical signal; second, this mechanical signal needs to be transduced into a neural representation that can be used by the brain; third, the resulting neural representation needs to be analyzed by central neurons to extract information useful to the animal. This chapter provides an overview of some aspects of the first two of these processes. The description is entirely focused on the mammalian auditory system, primarily on human hearing and on the hearing of a few commonly used laboratory animals (mainly rodents and carnivores). Useful summaries of non-mammalian hearing are available [1]. Because of the large size of the literature, review papers are referenced wherever possible.

  10. Acoustic analysis of changes in articulation proficiency in patients with advanced head and neck cancer treated with chemoradiotherapy. (United States)

    Jacobi, Irene; van Rossum, Maya A; van der Molen, Lisette; Hilgers, Frans J M; van den Brekel, Michiel W M


    Our aim was to characterize articulation proficiency and differences between tumor sites before and after chemoradiotherapy for advanced head and neck cancer with the help of acoustic measures. Our further goal was to improve objective speech measures and gain insight into muscle functioning before and after treatment. In 34 patients with laryngeal or hypopharyngeal, nasal or nasopharyngeal, or oral or oropharyngeal cancer, we acoustically analyzed nasality, vowel space, precision, and strength of articulation in 12 speech sounds (/a/, /i/, /u/, /p/, /s/, /z/, /1/, /t/, /tj/, /k/, /x/, /r/) before treatment and 10 weeks and 1 year after treatment. Outcomes were compared between assessment points and between tumor sites. Nasality in nonlaryngeal sites was significantly reduced by treatment. Most affected in articulation were the oral or oropharyngeal cancer sites, followed by the nasal or nasopharyngeal sites. One year after treatment, vowel space had not recovered and consonant articulation had weakened. Laryngeal sites were less affected in articulation by tumor or treatment. Analyses of articulatory-acoustic features are a useful instrument for assessing articulation and speech quality objectively. Assessment of a number of sounds representing various articulation manners, places, and tongue shapes revealed patterns of speech deterioration after chemoradiotherapy. The results suggest that patients' speech could benefit from articulation exercises to address changes in muscle coordination and/or sensitivity and to counteract side effects and "underexercise" atrophy.

  11. Springer Handbook of Acoustics

    CERN Document Server

    Rossing, Thomas D


    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...

  12. Acoustic Spatiality

    Directory of Open Access Journals (Sweden)

    Brandon LaBelle


    Full Text Available Experiences of listening can be appreciated as intensely relational, bringing us into contact with surrounding events, bodies and things. Given that sound propagates and expands outwardly, as a set of oscillations from a particular source, listening carries with it a sensual intensity, whereby auditory phenomena deliver intrusive and disruptive as well as soothing and assuring experiences. The physicality characteristic of sound suggests a deeply impressionistic, locational "knowledge structure" – that is, the ways in which listening affords processes of exchange, of being in the world, and from which we extend ourselves. Sound, as physical energy reflecting and absorbing into the materiality around us, and even one's self, provides a rich platform for understanding place and emplacement. Sound is always already a trace of location.Such features of auditory experience give suggestion for what I may call an acoustical paradigm – how sound sets in motion not only the material world but also the flows of the imagination, lending to forces of signification and social structure, and figuring us in relation to each other. The relationality of sound brings us into a steady web of interferences, each of which announces the promise or problematic of being somewhere.

  13. Sonification of acoustic emission data (United States)

    Raith, Manuel; Große, Christian


    While loading different specimens, acoustic emissions appear due to micro crack formation or friction of already existing crack edges. These acoustic emissions can be recorded using suitable ultrasonic transducers and transient recorders. The analysis of acoustic emissions can be used to investigate the mechanical behavior of different specimens under load. Our working group has undertaken several experiments, monitored with acoustic emission techniques. Different materials such as natural stone, concrete, wood, steel, carbon composites and bone were investigated. Also the experimental setup has been varied. Fire-spalling experiments on ultrahigh performance concrete and pullout experiments on bonded anchors have been carried out. Furthermore uniaxial compression tests on natural stone and animal bone had been conducted. The analysis tools include not only the counting of events but the analysis of full waveforms. Powerful localization algorithms and automatic onset picking techniques (based on Akaikes Information Criterion) were established to handle the huge amount of data. Up to several thousand events were recorded during experiments of a few minutes. More sophisticated techniques like moment tensor inversion have been established on this relatively small scale as well. Problems are related to the amount of data but also to signal-to-noise quality, boundary conditions (reflections) sensor characteristics and unknown and changing Greens functions of the media. Some of the acoustic emissions recorded during these experiments had been transferred into audio range. The transformation into the audio range was done using Matlab. It is the aim of the sonification to establish a tool that is on one hand able to help controlling the experiment in-situ and probably adjust the load parameters according to the number and intensity of the acoustic emissions. On the other hand sonification can help to improve the understanding of acoustic emission techniques for training


    National Research Council Canada - National Science Library

    Francisco Nairon Monteiro Júnior; Washington Luiz Pacheco de Carvalho


      This paper presents an analysis of the content in acoustics present in physics textbooks recommended by PNLEM, which used the same criteria of evaluation from used by experts in the analysis of such books...

  15. Eliminating transducer distortion in acoustic measurements

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Torras Rosell, Antoni; McWalter, Richard Ian


    This paper investigates the in uence of nonlinear components that contaminate the linear response of acoustic transducer, and presents a method for eliminating the in uence of nonlinearities in acoustic measurements. The method is evaluated on simulated as well as experimental data, and is shown...

  16. Phase conjugation of acoustic beams (United States)

    Bunkin, F. V.; Vlasov, D. V.; Kravtsov, Iu. A.

    The paper presents a classification of methods for the phase conjugation (PC) of wave fields of various physical natures on the basis of such nonliner interactions as stimulated scattering, and three- and four-wave interactions. Among the latter, attention is given to holographic (volume and surface) and parametric PC schemes, permitting PC with amplification. The possibility of developing phase-conjugated devices using acoustic PC devices on the basis of various nonlinear effects is considered. Experimental results pertaining to the PC of sound fields are presented, and possible applications of acoustic PC devices are indicated.

  17. Acoustic-gravity nonlinear structures

    Directory of Open Access Journals (Sweden)

    D. Jovanović


    Full Text Available A catalogue of nonlinear vortex structures associated with acoustic-gravity perturbations in the Earth's atmosphere is presented. Besides the previously known Kelvin-Stewart cat's eyes, dipolar and tripolar structures, new solutions having the form of a row of counter-rotating vortices, and several weakly two-dimensional vortex chains are given. The existence conditions for these nonlinear structures are discussed with respect to the presence of inhomogeneities of the shear flows. The mode-coupling mechanism for the nonlinear generation of shear flows in the presence of linearly unstable acoustic-gravity waves, possibly also leading to intermittency and chaos, is presented.

  18. PT-Symmetric Acoustics

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhu


    Full Text Available We introduce here the concept of acoustic parity-time (PT symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT-symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT-symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

  19. The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present) (United States)

    Adler, Robert F.; Huffman, George J.; Chang, Alfred; Ferraro, Ralph; Xie, Ping-Ping; Janowiak, John; Rudolf, Bruno; Schneider, Udo; Curtis, Scott; Bolvin, David


    The Global Precipitation Climatology Project (GPCP) Version 2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.5 degrees x 2.5 degrees latitude-longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The data set is extended back into the premicrowave era (before 1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the raingauge analysis. This monthly analysis is the foundation for the GPCP suite of products including those at finer temporal resolution, satellite estimate, and error estimates for each field. The 23-year GPCP climatology is characterized, along with time and space variations of precipitation.

  20. Acoustic source for generating an acoustic beam (United States)

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian


    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.