bluuebunny/crossref_metadata_2025 huggingface dataset:
Extraction of green fluorescent proteins with sonoporation
Authors: Kaddur Kadija , Delalande Anthony , Tranquart François , Midoux Patrick , Pichon Chantal , Bouakaz Ayache
Published: May 2008

The mechanism of permeabilization with sonoporation is not understood but the recurrent hypothesis assumes the formation of pores in the cell membrane. The aim of our study is to comfort this assumption by investigating whether ultrasound (US) and microbubbles could also facilitate outward transport of molecules across the plasma membrane through these probable pore formations. Stably transfected Hela-GFP cells were used and insonified with a 1 MHz unfocused transducer in presence of BR14 microbubbles (Bracco Research, Geneva) at different acoustic parameters. The percentage of Hela-GFP cells and the mean cell fluorescence intensity (FI) were measured by flow cytometry to evaluate the GFP release. While US alone did not affect the cells, the addition of BR14 microbubbles induced a significant decrease of FI and the percentage of Hela-GFP cells. A reduction of more than 50% of FI and GFP + cells was achieved between 400-600 kPa and 40-75 % of duty cycle during 2 minutes insonation. However a progressive recovery of Hela-GFP cells percentage and FI post-insonation has been observed which indicates a viable situation of Hela-GFP permeabilized cells allowing a restoration of GFP cell content. These results comfort pore formation hypothesis allowing transmembrane transport following molecular concentration gradient.
Frequency response of bubble pulsations in tubes with arbitrary wall impedance
Authors: Hay Todd A. , Cheung Theresa Y. , Hamilton Mark F. , Ilinskii Yurii A.
Published: May 2008

A model is presented for the linear pulsation of a small bubble in a tube with locally reactive walls but with otherwise arbitrary wall impedance. The model is based on the normal mode expansion of the Green's function presented by Morse and Ingard [Theoretical Acoustics (McGraw-Hill, 1968), Eq. (9.2.10)]. The specific case of a cylindrical tube is considered. For a bubble that is located in the center of the tube and that is small compared with both tube diameter and wavelength, the radiation impedance on the bubble is given by a summation of the normal modes evaluated in the center of the tube. From the radiation impedance, the frequency response of the bubble to an applied sound field is obtained. For tube walls that are either rigid of pressure release, the solution agrees with the frequency response calculated using the method of images for a square tube having the same cross-sectional area. In tubes with hard walls the resonance frequency decreases as tube radius decreases because of radiation damping. In tubes with very soft walls the radiation damping is negligible below the cutoff frequency of the lowest mode, and the resonance frequency increases slightly as tube radius is decreased.
Non-linear extensions to shell models of ultrasound contrast agents: theory and experiment
Authors: Pelekasis Nikos A. , Tsiglifis Kostas , Dollet Benjamin , De Jong Nico , Lohse Detlef , Versluis Michel
Published: May 2008

The standard UCA models, characterized by the area dilatation modulus and viscosity of the encapsulating membrane, are extended in order to account for deviations from linear material behaviour and for non-spherical pulsations. The former effect is captured by introducing a parameter that measures the degree of membrane softness, whereas the latter is modelled by introducing a bending elasticity. Lipid shells exhibit the phenomenon of 'thresholding behavior' where excursions in the relative area dilatation are measured only beyond a critical sound amplitude. Treating the lipid shell as strain softening reproduces this non-linear behaviour which can be further optimized by controlling the shell softness parameter. Such a tuning can be used to estimate the degree of softness for the contrast agent BR-14. Stability analysis allowing for shape distortions provides an estimate for the bending elasticity that reproduces the experimentally observed threshold for growth of surface modes. Phase diagrams are constructed for BR-14, based on high-speed optical observations and stability analysis. Both experiment and numerical analysis exhibit a smaller variation between the stability threshold of subsequent shape modes in the case of UCA's, as compared to free bubbles. Numerical simulations reproduce the experimentally observed saturation of growing shape modes for pre-stressed UCA's.
Delivery of antibacterial-nanoparticles into dentinal tubules with high intensity focused ultrasound
Authors: Fong Siew Wan , Shrestha Annie , Shi Zhilong , Khoo Boo Cheong , Kishen Anil
Published: May 2008

High-Intensity-Focused-Ultrasound (HIFU) when applied clinically often result in the formation of cavitation bubbles in the nearby fluid or tissue which collapse with high-speed jets and can be utilized for particle delivery. Bacteria residing in anatomical complexities and dentinal tubules resist conventional disinfection procedures during root canal treatment. This study aims is to evaluate the efficacy of jet flow produced by collapsing cavitations to push antibacterial nanoparticles into the areas inaccessible to conventional treatment. Eight dentin blocks of 8x3x1.5mm3 were prepared from the root region of freshly extracted single rooted tooth samples and divided into two groups: (1) Control and (2) Nanoparticles. The samples were placed in sterile deionized water and nanoparticles suspension (1mg/ml) for groups 1 and 2 respectively. HIFU at 27 kHz for two minutes was employed. The samples were then sectioned to expose the dentinal tubules and viewed under field emission scanning electron microscopy and Energy Dispersive X-ray analysis to ascertain the depth of penetration of the nanoparticles. The findings from this study suggested that HIFU treatment resulted in the significant penetration and coating of the dentinal tubules with nanoparticles. HIFU can be used as a potential tool for the delivery of antibacterial nanoparticles to disinfect the root canals.
Ultrasonic method to define human serum blood total protein and protein fractions
Authors: Klemina Anna
Published: May 2008

Research of ultrasonic characteristics of biological liquids for purposes of medical diagnostics is the important task. Ultrasonic method to define total protein and protein fractions - albumin, αl -, α2 -, β -, γ - globulin's of human serum blood is discussed. This method is based on the precise measurements of velocity and absorption of ultrasonic waves in serum blood and its modified solutions under different temperatures from range (15-40)0C. The measurements of ultrasonic velocity and absorption in samples serum blood fulfils by means of method ultrasonic interferometer constant length or resonator method. The precision of relative measurements of velocity by means of this method is 10-5 and absorption is 10-3, temperature stability is the order of 10-3 0C. Protein fractions define by means of decision of linear system of equations where in the character of unknown components consider these protein fractions. Comparison of data of different patient obtained by traditional electrophoreses method with data of ultrasonic method shows very high correlation of all protein fractions and total protein. This work was supported by RFBR and Leading Scientific Schools grants.
Ultrasound elasticity assessment of in vivo human achilles tendons during a quick-release exercise
Authors: Defontaine Marielle , Bentahar Mourad , Canon Francis
Published: May 2008

An ultrasound (US) axial transmission technique has been developed to assess in vivo real time tendon biomechanical properties during calibrated exercises. The US propagation velocity changes are indeed related to the tendon visco-elasticity variations. We propose to monitor the propagation velocity changes during a very short period of time corresponding to the tendon/muscle complex release just after a sub-Maximal Voluntary isometric Contraction (MVC). This measurement is repeated for several sub-MVC amplitudes. The propagation velocity variations, linearly related to the torque measurements, allow to estimate a stiffness index, essentially due to the Series Elastic Component of the Achilles tendon. This study has been performed in collaboration with the UMR 6600 (UTC, France), and we have used the Ergometer they developed a few years ago. The US device is composed of a 1.8 MHz US probe (1 emitter, 20 receivers), and an electronic module (Althaïs Technologies, France) allowing real time and synchronous acquisitions of US RF signals and auxiliary inputs (Torque, angular position). Four healthy subjects were asked to develop several submaximal voluntary isometric contractions, and the sole was suddenly released (sub MVC to relaxed state, 2s, 2kHz). This protocol was repeated two times with foot and probe repositioning.
Thin film thermo-viscous damping in miniature condenser microphones
Authors: Le Van Suu Thierry , Honzik Petr , Durand Stephane , Joly Nicolas , Škvor Zdeněk , Bruneau Michel
Published: May 2008

The thermo-viscous damping due to the thin fluid film between the membrane and the backing electrode strongly influences both the sensitivity of the condenser microphones in the lower frequency range and the upper limit of the frequency bandwidth. Nowadays, most of the MEMs microphones use a perforated backing electrode while some authors suggest that a continuously curved backing electrode could enhance their performances (among avantages in the design when etching). The present paper provides two kinds of modeling for such microphones with a tapered fluid film: the first one lies on Kirchhoff-network analysis (neglecting cross-coupling between elements) whereas the second one is based upon the direct resolution of the set of basic equations (including heat transfer phenomena). The results are presented and discussed for both models in the cases of flat, parabolic, and stepped shapes backing electrode. Finally, the pressure field in the fluid film, computed (for an axisymmetrical configuration) using the above-mentioned models, is compared to the one computed with a new FEM formulation taking into account both viscous and thermal phenomena in the boundary layers.
Piezoelectric silicon microphones for aeroacoustics applications
Authors: Sheplak Mark
Published: May 2008

This talk presents the development of several microelectromechanical systems (MEMS)-based piezoelectric measurement microphone technologies for aeroacoustic applications. Piezoelectric MEMS microphones offer the promise of reducing cost, improving performance, and increasing mounting flexibility over existing conventional microphone technologies. Specifically, a microphone with no external power requirement has a key advantage for a large-channel count, widespread deployment. The modeling and design aspects of these devices are reviewed. First, the electroacoustic transduction is predicted via piezoelectric composite plate theory. Lumped element models are then synthesized to describe the dynamic characteristics of the microphone diaphragm and the cavity/vent structure. Constrained nonlinear design optimization using a sequential quadratic programming scheme is then performed to determine the microphone design parameters. From a fabrication perspective, the main drawback to silicon-micromachined piezoelectric devices is material integration and compatibility with standard micromachining. Several different device structures and fabrication approaches will be discussed in this talk. Representative results from a lead zirconate-titanate-based device will then be presented. Finally, unresolved technical issues are summarized for future sensor development.
Speech separation based on law of causality
Authors: Fujii Kensaku , Nakano Hirofumi , Muneyasu Mitsuji
Published: May 2008

This paper proposes a microphone array system separating speech signals, based on a different principle from independent component analysis (ICA). This system applies linear prediction error filters to microphone outputs, and using the prediction errors, adjusts the coefficients of adaptive filters. In this case, only the prediction errors satisfying the low of causality become available for the adjustment; consequently, this system can steer a null toward a direction satisfying it. The permutation problem discussed in ICA can be thereby avoided. This system also can compensate the separated speech signals by using adaptive filters, and finally, can provide high quality speech signals. This paper moreover verifies the performance of the proposed system by using speech signal data measured in an ordinary room. This result shows that the proposed system works well even in reverberation environment.
Ultrasonic Technique for the Quality Control of Water Containing Clay
Authors: Hamine Adil , Faiz Bouazza , Izbaim Driss , Moudden Ali
Published: May 2008

In this work a new method is developed to control the stopping water using an ultrasonic technique. This technique allows controlling the presence of clay grains by measuring the attenuation of the ultrasonic waves. The dimension of clay grains used in this study is about 10 μm. For slurries with different weight percent of clay 1% or less, high sensitivity is gained by analyzing attenuation measurements. At high clay concentrations, sufficient sensitivity is obtained by analyzing data from a simple transmission. The experimental results show that the sound attenuation due to particles varies linearly with mass fraction.
A lossy, one-dimensional, linear systems model for piezoelectric transducers containing opposing zones of polarization
Authors: Ramadas Sivaram Nishal
Published: May 2008

Inversion layer transducers (ILT), consisting of two or more active, piezoelectrically opposed regions along their thickness direction, have attracted considerable interest in the recent past, due to the potential for wide bandwidth and even harmonic sensitivity. However, design and manufacture of such ILT devices are not straightforward due to the large number of degree of freedom involved. This paper presents the development of a lossy, computationally efficient analytical model to design ILT configuration. The mathematical formulation for a generalized linear systems model, applicable to arbitrary ILT configurations is presented. The model describes multiple active and passive layers, including zones of variable piezoelectric polarization, matching layers and bondlines. The model is extended further to include mechanical wave absorption in both the active transducer element and the propagating channel, and the effect of such frequency dependant loss on the operational characteristics of an ILT device is reported. Several simulation results are shown to demonstrate the feasibility of the approach together with a comparisonal analysis to conventional finite modeling techniques and experimental evaluations. The results indicate clearly that such approximate analytical techniques can be used effectively to design optimal ILT configurations.
Pedal notes of brass instruments, a mysterious regime of oscillation
Authors: Gilbert Joël , Aumond Pierre
Published: May 2008

In reed and brass instruments, sound is produced by self-sustained mechanical oscillations driven by an airflow coming from a pressure supply such as the player's lungs. Most of the time, the fundamental frequency of a periodic oscillation is close to, and mainly controlled by one given acoustic mode. Even though, these oscillations are the result of a complex non-linear coupling between all the acoustic modes and the mechanical valve. The pedal note, which is the lowest note that can be sounded on a brass instrument, is well-known as a counter-example. Eighty years ago, Bouasse did an experiment by replacing the brass mouthpiece by a reed mouthpiece on a brass instrument, and obtained a pedal note a fifth below! An elementary model dedicated to both cane-reed and lip-reed instruments can be used. In order to investigate the sound production of pedal notes, a simulation method based on modal decomposition of bore and reed dynamics has been carried out. Then, the periodic solutions of this model are obtained, and the mysterious oscillation regimes of Bouasse experiment are discussed.
Nonlinear effects in the propagation of outgoing and reflected pulses inside a trombone
Authors: Rendón Pablo L , Orduña-Bustamante Felipe , Sorrentini Jacques , Pérez-López Antonio
Published: May 2008

While sound propagation in a trombone can be generally quite properly described by linear models, it is commonly acknowledged that the "brassiness" of sound produced at high amplitudes is associated to nonlinear effects. Whether these effects are due principally to propagation inside a long, narrow pipe, or to the production of sound at the mouthpiece is still unclear. We present experimental measurements taken both from a long, narrow tube, and an actual slide trombone from which it is observed that the scale of nonlinear effects seems to be greater for outgoing pulses than for the reflected pulses at the open end of the trombone or tube. A theoretical model is also proposed, based on weakly nonlinear perturbations of linear theory, and is validated both by experimental results and by numerical simulations. The results indicate that both the amplitude and the shape of the initial perturbation produced at the trombone mouthpiece have an effect on the scale of propagation nonlinearity present inside the trombone resonator, and thus also on the "brassy" quality of sound.
External sound radiation of vibrating trombone bells
Authors: Nief Guillaume , Gautier François , Dalmont Jean-Pierre , Gilbert Joël
Published: May 2008

The issue of the influence of bell vibrations on the sound of brass instruments is still debated. For such instruments, external sound field is the superposition of the sound field resulting from acoustic oscillations of the air column and the sound field resulting from direct radiation of the bell and walls. The aim of this paper is to quantify the bell contribution with respect to the air column one, and to examinate the conditions for which the former may become audible. For this purpose, the structural modes of a trombone bell are identified using an experimental modal analysis. For each mode shape, the radiation efficiency is computed using a model of the radiated sound based on a distribution of equivalent monopoles. A critical frequency is defined for the bell and allows us to determine at which condition a given structural mode is radiating. Measurements of the sound power radiated by a trombone excited by an harmonic acoustic source are carried out when the bell is free to vibrate and when bell vibrations are damped. Comparison between the two configurations is analyzed using the developed model and is used to quantify the sound power due to bell vibrations.
Tristan trumpet or English horn
Authors: Pyle Robert W. , Klaus Sabine K.
Published: May 2008

In Act III of his opera "Tristan und Isolde", Richard Wagner wrote an instrumental tune to be (apparently) played by a shepherd. This was originally scored for, and is customarily played by, an off-stage cor anglais. Wagner indicated that he would have preferred some form of wooden trumpet, similar to a small-scale alphorn. A few such instruments have been built. These are pitched in 4-foot C, with a pear-shaped bell similar to that of the cor anglais, and a single metal whole-tone valve. The Utley Collection at the National Music Museum, The University of South Dakota, has two such instruments: one made by Gebrüder Alexander (Mainz), formerly used in the National Opera in Prague (Volkstheater), the other a copy of a trumpet by Martin Lehner, Munich, in the possession of the Staatsoper Dresden, made by Andreas Schöni and Rainer Egger (Bern and Basel). We will compare sound spectra of the Tristan trumpet with that of the cor anglais. We will also compare the acoustic input impedance of the Tristan trumpet with that of an ordinary trumpet of the same pitch.
Harmonicity of trumpet modes
Authors: Hoekje Peter L. , Attaway Michael
Published: May 2008

The mouthpiece on a brass instrument is generally removable but constitutes an important part of the whole instrument. In the frequency domain, it can be considered to provide a frequency dependent equivalent length that increases with frequency up to the Helmholtz resonance frequency fpop of the mouthpiece itself. Geometrical changes that affect the total volume or the fpop of the mouthpiece will affect the harmonicity of the nearly harmonic normal modes of the instrument. Using heterodyne filter analysis, the development of the frequency components and their amplitudes were measured for low trumpet notes, both for repeated attacks of short notes and for sustained note crescendos from pianissimo to fortissimo. The measurements were repeated after the mouthpiece was modified to improve the harmonicity of the normal modes. During both attack and crescendo tests, the modified mouthpiece was associated generally with more stable frequencies of the partials and more even development of the amplitudes of the partials.
Experimental investigation of the aeroacoustic coupling of self-sustained tones to non-planar modes of a resonator
Authors: Glesser Martin , Valeau Vincent , Sakout Anas
Published: May 2008

Recent studies have shown that a jet-slot oscillator (ie, an aeroacoustic self-sustained source consisting of the impingement of the vortical structures of a plane jet on a slotted plate) can be coupled to non-planar modes of the flow-supply duct. This phenomenon occurs in the particular case where the jet-exit and the obstacle are misaligned in the spanwise direction. This paper presents an experimental investigation of the excited modes as a function of the plate inclination angle, and of the distance between the jet-exit and the slot. It is shown that: (i) the vortex-tubes spanwise morphology is governed by the nature of the transverse excited modes, and (ii) the vortices tend to impinge on the inclined obstacle almost in phase in the spanwise direction, in order to enhance the coherence of the interaction along the slot. Moreover, an elementary analytical model of the resonant acoustic field shows that the ratio between the transverse and planar modes amplitudes is tuned by the system in order to keep this coherence maximum. The existence of a so-called "opposed transverse mode" is also shown, generating vortices with an inclination angle opposed to the plate inclination angle.
Sound power level measurement of Sheng, a Chinese wind instrument
Authors: Zhao Yue Zhe , Wu Shuo Xian , Qiu Jian Zhen , Wu Li Ling , Huang Hong
Published: May 2008

Sheng is one of the Chinese traditional wind instruments. But its sound power level has never been carefully measured. In this paper, the sound power measurements of Sheng were performed for the first time in a reverberation chamber according to ISO standard and Chinese national standard. Two qualified musicians performed on their own instruments in the center of the reverberation chamber. The radiated sound energy and the dynamic ranges of the Sheng were investigated by four channel acoustic measuring equipments. Typical sound power values were obtained through averaging and the results were reported in this paper. It was showed that the mean forte sound power level can reach up to 98dB with a dynamic range of 22.5dB when music scale was performed. The method discussed here is valuable for the sound power measurements of other musical instruments. The measurement of the sound power radiated by national musical instruments lays foundations for the investigation into the acoustics of national music halls.
Investigation of clarinet reed auto-oscillations with digital Fresnel holography
Authors: Mounier Denis , Picart Pascal , Leval Julien , Piquet Francis , Boileau Jean-Pierre , Guimezanes Thomas , Dalmont Jean-Pierre
Published: May 2008

This paper describes a full field digital holographic method for studying the cinematic of the vibration of the clarinet reed in playing conditions in an artificial mouth. Since many years, LAUM is interested in studying musical instruments and particularly the clarinet. The behaviour of such an instrument is particularly complex because it depends on aerodynamics, contact between reed and beak, and interaction with the lip of the musician. Thus, visualisation of the full movement of the reed in playing conditions is necessary to better understand physics of the clarinet. However, free oscillations have high amplitude of several hundreds of micrometers, thus corresponding to several thousand times the laser wavelength. The analysis of the movement is performed by a laser tracking of the vibration. It is demonstrated that it is possible to reconstruct a synthetic high amplitude deformation of auto-oscillations encoded with digital Fresnel holograms. The setup is applied to the auto-oscillation of the clarinet reed in a synthetic mouth. Tracking of the vibration is performed by using the pressure signal delivered by the mouth. Experimental results show the four steps of the reed movement and especially emphasize the shocks of the reed on the mouthpiece.
A concise overview of present knowledge of bowed-string gestures and their acoustical consequences
Authors: Guettler Knut
Published: May 2008

During the few years of our young millennium the picture of what happens acoustically when the bow is drawn across the string has become considerably more complete. A few surprises emerged along the way: the bow's position on the string does not seem to influence the spectral envelope-and different from what Schelleng predicted-there seems to be no clear correlation between minimum bow force and the bow speed. The intention of this presentation is to give a brief survey of related studies and their results, as well as pointing out some of the blank spots still remaining on the canvas.
How whisper and croak phonation affect vocal tract resonances
Authors: Swerdlin Yoni , Smith John , Wolfe Joe
Published: May 2008

The whisper and croak modes of phonation provide convenient broad band excitation of the vocal tract and thus give relatively precise information about tract resonances. How closely do the measured resonances for these mechanisms approximate those of normal speech? We measured the frequencies of the first four resonances (R1-R4) in normal, whisper and croak phonation. Subjects produced pairs of these phonations in the same vocal gesture. Formants were used to measure the frequencies (R1-R4) for the non-periodic phonations and broad band excitation at the mouth was used to measure them with similar precision in normal speech. For R1 to R4 respectively, whispering raised the resonant frequencies by 255±90 Hz (92)*, 115±105 Hz (119)*, 125±125 Hz (109)* and 75±120 Hz (118)*, (mean ± standard deviation (n), asterisks show significance at the 5% level). These values, and their decrease with increasing frequency, are consistent with the effect of the increased glottal opening in whispering only if the increased opening is large. A supra-glottal narrowing in the tract could also help raise the frequencies of resonance. Croak phonation raises the resonant frequencies respectively by 45±50 Hz (121)*, 10±60 Hz (124), 65±120 Hz (109)* and 15±110 Hz (108).
Vocal folds and ventricular bands in interaction: comparison between 'in vivo' measurements and theoretical predictions
Authors: Bailly Lucie , Henrich Nathalie , Pelorson Xavier , Gilbert Joël
Published: May 2008

Period-doubling occurrences have been found during singing phonations such as Mongolian Kargyraa throat singing or Sardinian A Tenore Bassu singing. The combined vibrations of vocal folds and ventricular bands have been observed during the production of such low-pitch bass-type sounds. The present study aims at better understanding the physical interaction between the ventricular-bands vibration and the vocal-folds self-sustained oscillations. In this paper, the vibratory properties of both vocal folds and ventricular bands in interaction are analysed on a professional singer by means of acoustical, electroglottographic signals and synchronized glottal images obtained by high-speed cinematography. Using the detected glottal and ventricular areas, the aerodynamic behavior of the laryngeal system is simulated using a simplified aerodynamic modelling previously validated "in vitro" on vocal-folds and ventricular-bands replica. An estimate of the subglottal pressure along with the ventricular aperture extracted from the "in vivo" data allows a theoretical prediction of the glottal aperture. The "in vivo" measurements of the glottal aperture are then compared to the simulated estimations. The influence of the subglottal pressure is also discussed.
How loud is low frequency noise
Authors: Broner Norm
Published: May 2008

When it comes to assessing noise, the conventional wisdom is that the loudness of a sound will correlate well with its perceived annoyance. On this basis, the A-weighted sound pressure level is also assumed to correlate with the potential percieved annoyance of a sound. This might well be a reasonable assumption for mid range frequency sounds. But for low frequency sounds, particularly below 63 Hz, the assumption that loudness is correlated highly with perceived annoyance breaks down. Indeed, while loudness adaptation may occur for low frequency sound, the annoyance can increase with time. Thus, with time, the annoyance may keep increasing while the apparent loudness decreases!
Metric assessment of subjective annoyance due to low frequency aircraft noise
Authors: Hodgdon Kathleen , Nickerson Matthew L. , Atchley Anthony A. , Gabrielson Thomas
Published: May 2008

A low frequency noise study was conducted at the Pennsylvania State University to investigate human response to the low frequency content of aviation noise. Metric assessment included level based and loudness metrics, including time-varying loudness. Current predictive noise models and metrics may underestimate the impact of low-frequency noise produced by aviation noise. Assessing the role of low frequency noise on human response will facilitate understanding how this type of noise can impact communities. Indoor recordings of aircraft arrivals and departures at Washington Dulles International Airport made in 2004 were used to assess subjective noise annoyance. These recordings and low-frequency variants of these recordings were reproduced for subjects through the Gulfstream Supersonic Acoustic Signature Simulator II (SASS II); the signatures were then rated for annoyance. Subjective judgments were statistically analyzed and compared against objective metrics that were calculated for each signature. Results are shown that all things being equal higher levels of low-frequency content in aircraft noise can result in increased annoyance in subjects. The C-weighted sound exposure level was found to correlate well with the subjective annoyance response.
Sound character ratings by experienced and naive listeners
Authors: Weber Reinhard , Hansen Hans
Published: May 2008

In the frame of a cross-cultural study on pitch perception of tones in noise, two different groups of participants took part in the listening tests in France. Trained in psycho-acoustic evaluation tasks, members of the laboratory belonged to the first group, whereas the second one consisted of naïve students. 25 stimuli with different tone-to-noise ratios were presented via headphones and, using a semantic differential of 14 adjective pairs, the participants made their judgements on common seven step scales. For both listening groups a PCA of the results led to the same three orthogonal dimensions of the perceptual spaces. They were identified in accordance to Namba's findings as 'pleasant', 'metallic' and 'powerful' factors with an interesting difference: For the trained, the 'metallic' factor, preferably describing the sound character, explained the largest amount of total variance as first factor. The 'pleasant' factor as 'evaluation' dimension took the second place and the 'powerful' factor ranked behind. However, the order of the first two factors was reversed for the untrained listeners. For them the variance of 'pleasant' factor was a bit higher compared to the 'metallic' factor. So the variance in sound character judgements was higher for the trained compared to the untrained listeners.
Optimising the value of sound quality evaluations by observing assessors' driving strategies
Authors: Giudice Sebastiano S. , Jennings Paul , Cain Rebecca , Dunne Garry , Allman-Ward Mark , Williams Roger
Published: May 2008

Traditionally vehicle sound evaluations have been conducted either whilst driving a car or by auditioning fixed test conditions in a listening room. On-road testing provides the right context but the results are often inconsistent and unrepeatable. Furthermore it is not possible to evaluate prototype sounds or carry out back-to-back comparisons. In-room evaluations improve the statistical confidence, but the context of the assessments is unrepresentative. Interactive NVH vehicle simulators enable assessments to be performed in a setting representative of real appraisals. Accurate sounds can now be generated in real-time, and assessors can adopt a driving strategy that allows their own interpretation of the attributes. The benefits include the opportunity to understand how preferences are formed by assessors, albeit with added complexities. Different assessors may be associating their preferences on different operating conditions which have different acoustical properties. Therefore for engineers to identify the key features that influence perception they need to be able to relate the driving strategies with the subjective preferences. This paper reports on new observational methods which capture assessors' decision making strategies. It demonstrates how these help in relating subjective preferences to vehicle operating conditions and how to design a structured evaluation to reduce sources of experimental error.
Perception of simple sounds from an emotional point of view
Authors: Sköld Anders , Bergman Penny , Vastfjall Daniel , Colebring Andreas
Published: May 2008

In sound perception the focus often lies in the cognitive aspect of the sound. We argue that the emotional aspect has to be added to get a fuller picture of sound perception. By using emotions as parameter in design of auditory alerts, one can reach a more accurate reaction to the alert. In this paper we studied the emotional connection to some attributes, common in music psychology, that are possible to describe by simple parameters. Short stimuli were created from these parameters in a factorial test design. The sounds were presented over headphones, with same signal fed to both ears, to 30 participants. The participants were asked to rate level of valence and activation, using a pictorial scale (SAM). Statistical differences was mostly found in ratings of activation, but differences were also shown in valence ratings. Results will be discussed in relation to theories of sound perception as well as music psychology.
Emotional bias for the perception of rising tones
Authors: Tajadura-Jiménez Ana , Väljamäe Aleksander , Vastfjall Daniel
Published: May 2008

Sounds with rising and falling intensity are often perceived, respectively, as approaching or receding sound sources. Research has shown the existence of biases both at perceptual and neural levels towards approaching versus receding sounds. It has been suggested that these effects might be accounted to a greater biological salience of approaching sounds. In the present study we investigated whether this asymmetry could be also explained by emotional theories. Approaching and receding tones, followed by neutral, negative or positive photographs, were presented. Participants were required to make a speeded three-alternative forced choice (3AFC) task regarding their feelings towards the photographs. Reaction times (RTs) to this task, together with self-reported valence (pleasantness) and arousal (activation) ratings for the photographs were collected. In addition, participants' electrodermal activity (EDA) and facial electromyography (EMG) when listening to the sounds were measured. Participants responded faster to photographs preceded by approaching tones, especially for photographs with a negative emotional content. Both the intensity range and the period of intensity change of the sounds had a significant effect in RTs. Taken together, these results suggest that approaching sounds induce a greater emotional response on listeners, which might modulate subsequent attentional and perceptual processes.
Survey of sound quality research and applications in the information technology industry
Authors: Baird Terry
Published: May 2008

Traditionally, emission sound power level has been the key attribute measured and reported for describing IT equipment acoustic performance. More recently, designers and manufacturers of IT equipment have come to realize that customer satisfaction or annoyance is not dictated by sound power alone, but is dependent on many sound quality attributes as well. Additionally, sound power level tends to be a poor indicator of equipment condition or component degradation where other tools are required for diagnosis and characterization. This paper reviews key research and trends over the last several years using psychoacoustic principles and analyses, as well as case studies of specific applications in the IT sector.
Identification and Classification of Noise Patterns
Authors: Sottek Roland
Published: May 2008

Sound quality evaluation is a challenge due to spectral and temporal structures of noise. Tonal components, howling sounds and modulated signals are often the cause of customer complaints. Thus, besides frequency-weighted level like dB(A) or loudness, additional parameters are required. Besides time-varying loudness, other psychoacoustic parameters like sharpness and roughness can be used for sound quality evaluation. Sharpness considers the amount of high frequency components of a noise, and roughness evaluates modulation characteristics. In addition, a metric combining modulation spectral analysis with loudness calculation has been introduced. Some years ago, a "Hearing Model" was developed with the intention of explaining and describing psychoacoustic effects. Applying the Hearing Model to sound quality tasks allows evaluating the spectral and temporal patterns of a sound ("Relative Approach" analysis) where absolute level or loudness is often without significance. The Relative Approach analysis emphasizes all relevant signal components concerning human auditory perception: tonal and transient signals. For extracting and evaluating individual patterns further signal-processing steps are necessary. The paper presents different methods for effective sound quality evaluation of noise and their application to several examples.
Capturing blocked-entrance binaural signals from open-entrance recordings
Authors: Hammersho/i Dorte , Hoffmann Pablo F. , Olesen So/ren K. , Rubak Per
Published: May 2008

Binaural recordings enable us to capture all sound attributes including spatial information, room effect, and source characteristics in a given environment. It has been shown that blocked-entrance binaural recordings provide advantages over open-entrance recordings, primarily because the blocked-entrance recordings is not influenced by the ear canal acoustics of the individual for which it is recorded. However, blocking the ear canal for recoding imposes an obvious disruption to normal hearing conditions, which may be unacceptable for applications in which binaural audio capturing is desired but without interfering the individual's hearing and doing. In this work we propose a strategy for the recording of binaural audio with minimal hearing interference, and for transforming these recordings to blocked-entrance versions that are more suitable for analysis and reproduction of binaural audio in a more general context. To this purpose, equalization filters are derived from the ratio between blocked and open ear canal transfer functions. Different transfer-function measuring techniques and inverse filtering methods are evaluated.
The sound wave reflection from the corrugated plane streamlined by the low Mach number shear flow (generalized Miles mechanism)
Authors: Mironov Mikhail , Belyaev Ivan , Solntseva Vasilisa
Published: May 2008

The plane sound wave reflection from the periodically corrugated plane streamed by the parallel shear flow is studied. The incident wave scatters on corrugations and gives both the mirror reflected sound wave and two inhomogeneous nonpropagating in the normal to the plane direction waves. One of the inhomogeneous waves goes in the same direction along the plane of the flow and the second one in the opposite direction. The first inhomogeneous wave interacts with critical layer of flow according to Miles mechanism (which was originally applied to the generation of surface waves by the wind (JFM: 1957, 1959)) and reflects from this layer back to the plane. After that this inhomogeneous wave scatters from the corrugated plane and gives some additional part to the mirror reflected sound wave. The total reflection coefficient of sound wave appeared to be more than 1. The angle dependence of the reflection coefficient is analyzed. The equivalent impedance is calculated. The obtained amplification is compared with thermal and viscous surface losses
On a stability of the shear flow with a tangential discontinuity in the presence of a small scatterer
Authors: Kanev Nikolay , Mironov Mikhail
Published: May 2008

It is well known a tangential discontinuity of velocity in the shear flow is unstable. That instability is convective i.e. all disturbances of the tangential discontinuity grow exponentially but they are carried away by the flow downstream so that after all the amplitude of sound field generated by the tangential discontinuity will decrease at any fixed point. In the presented paper we consider the problem when a small scatterer is placed near the tangential discontinuity. It appears this system can be absolutely unstable under the definite position of the scatterer. It means that the appearance of any disturbance of the tangential discontinuity will result in rising of the amplitude of sound field at every point of space. The cause of absolute instability is a feedback provided by the scatterer and the type of instability does not depend on the size of the scatterer. An absolutely unstable system behaves as an autogenerator and radiates tone or multitone sound. So the obtained result explains the possible mechanism of noise generation in systems with tangential discontinuities and gives some hints about noise control in such systems.
Spectral attenuation of sound in dilute suspensions with nonlinear particle relaxation
Authors: Kandula Max , Lonergan Michael
Published: May 2008

Theoretical studies on the dissipation and dispersion of sound in two-phase suspensions have been briefly reviewed. Previous studies (theory of Temkin & Dobbins, JASA, Vol. 40, No. 2, pp. 314-324, 1966,) on the sound attenuation in particle-laden flows under Stokesian drag and conduction-controlled heat transfer have been extended to accommodate the nonlinear drag and heat transfer. It has been shown that for large particle-to-fluid density ratio, the particle Reynolds number bears a cubic relationship with {\omega}{\tau},where {\omega} is the circular frequency and {\tau}the Stokesian particle relaxation time. This dependence leads to the existence of a peak value in the linear absorption coefficient occurring at a finite value of {\omega}{\tau}. Comparison of the predictions with the test data of Norum (AIAA-2004-2976) for the spectral attenuation of sound with water injection in a perfectly expanded supersonic jet (Mach number of 1.45) shows a satisfactory trend of the proposed theory. It is found that the nonlinear particle relaxation processes (particle drag and heat transfer) are primarily responsible for reduction in the linear absorption coefficient of sound at high frequencies.
Aeroacoustic simulation of automotive ventilation outlets
Authors: Adam Jean-Luc , Ricot Denis , Dubief Flavien , Guy Christine
Published: May 2008

In this work we have numerically studied aeroacoustics of automotive ventilation outlets. Simulations are performed with the CFD software PowerFLOW based on Lattice Boltzmann method (LBM). Low dissipative LBM scheme enables to compute aeroacoustic sources generated by turbulence fluctuations and to propagate them in the same simulation. In a first step we validate the ability of LBM for propagating acoustic waves in ducts and radiating them at open end terminations. In a second step, aeroacoustic simulations on automotive vents will be presented and compared with experimental data obtained from a DoE (Design of Experiment). This DoE is based on an idealized outlet with variing parameters (number and lenght of grid blades, grids spacing ...) which gives 18 distinct geometrical configurations. All these configurations have been simulated with PowerFLOW and measured with a new test facility (built in the Renault Research Department). The large number of tested geometries and the statistical analysis of the DoE give an accurate idea of the capability of PowerFLOW, and more generally LBM, to correctly simulate the generation and propagation of aeroacoustic sources for a complex geometry. Results will be presented and discussed.
Implementation of the noise directive in music and entertainment sector in Finland
Authors: Toppila Esko , Olkinuora Pekka , Airre Pekka
Published: May 2008

In the noise directive (2003/10/EC) the member countries were obliged to develop codes of conduct for the music and entertainment sector. In Finland the code of conduct was adopted into use in February 2007. According to this code of conduct the workers in the music and entertainment sector consist of performers (musicians, singers, conductors and actors), staff exposed to music (waiters,...) and teacher who teach music in schools. Guidelines were designed based on the worker group and the type of employment. In this approach the performers, who actually produce the "noise", must be able to monitor the sound levels in real time. Restaurants and music halls design the protective actions for other staff based on the assumption that predefined sound level is not exceeded the premises. The same principle is applied to schools. For temporary staff there must be hearing protectors available. Also the need for damping and use of quieter instruments is recognised. The code of conduct give the principles for the hearing conservation, but for the music and entertainment sector direct application of the principles is too complicated. Implementation examples are needed for all exposure patterns. This work is going on now in Finland.
Two-level description of environmental sounds: comparison and generalization of 4 timbre studies
Authors: Minard Antoine , Susini Patrick , Misdariis Nicolas , Lemaitre Guillaume , McAdams Stephen , Parizet Etienne
Published: May 2008

The purpose of this study is to propose a scheme of environmental sound description based on the comparison and generalization of 4 timbre studies of diverse environmental sounds. In the medium term, the aim is to make the indexing and classification processes of this kind of sound automatic, which is essential for sound content-based searching and browsing methods using perceptual models of environmental sounds. First, we inventoried the stimuli, experiments and perceptual results of these 4 studies. Then, we experimentally identified 3 main environmental sound categories that constitute this overall sound dataset: impact sounds, motor sounds and instrument-like sounds. We developed an efficient tool that predicts these categories according to only two acoustic features calculated on the signal. However, because of the specificities of the sound production of these three categories, each of them has its own timbre space. Therefore, we finally used perceptually relevant acoustic features to explain these timbre spaces, according to the main acoustic characteristics that define each sound class. We found that timbral brightness is a common feature used to discriminate sounds in all classes, while other particular features are specifically used within each class. [Work partially supported by the SamplerOrchestrator project of the ANR program]