bluuebunny/crossref_metadata_2025 huggingface dataset:
A combined platform for b-mode and real-time optoacoustic imaging based on raw data acquisition
Authors: Fournelle Marc , Maass Kirsten , Fonfara Heinrich , Welsch Hans-Joachim , Hewener Holger J. , Günther Christian , Lemor Robert M.
Published: May 2008

Optoacoustic imaging is a new promising medical imaging modality combining the benefits of optical and acoustical methods. Optoacoustics allow to make the high intrinsic optical contrast in biological tissue accessible to acoustical detection. In addition, the possibility of using nanoscaled contrast agents makes of optoacoustics an ideal candidate for molecular imaging. While optoacoustics are an emerging imaging modality with poor clinical experience, ultrasound is widely used for diagnosis. Accordingly, optoacoustic images are much harder to interpret than b-mode images. For this reason, we developed a hardware platform which allows combined b-mode and optoacoustic imaging using a 2-in-1 transducer with arrays of different frequency for the two modalities. The system supports simultaneous data acquisition of 128 channels with a sample rate of 80 MSamples allowing the usage of transducers with frequencies up to 20 MHz. The unprocessed data is transferred to a PC where the images are reconstructed with algorithms adapted to both modalities. A software for hardware control, data processing and visualization in real-time was developed. B-mode and optoacoustic images of tissue phantoms were generated and different types of nanoparticles were used as optoacoustic contrast agent. Further, first in-vivo measurements underlying the high potentials of the combined system were obtained.
A maximum likelihood method for obtaining integrated attenuation from ultrasound transmission mode measurements
Authors: Willemink Rene G. , Manohar Srirang , Slump Kees H. , Van Der Heijden Ferdi , Van Leeuwen Ton G.
Published: May 2008

In photoacoustic imaging applications an image is reconstructed of the optical absorption distribution the imaged object. The photoacoustic measurements however are also dependent on acoustic properties of the imaged object. By estimating the acoustic properties from photoacoustic measurements, we can improve the performance of the optical absorption reconstruction and allow for the imaging of separate acoustic modalities. We derive and evaluate a maximum likelihood estimator for the measurements of integrated acoustic attenuation. This estimator is applicable to media like soft tissue. In this kind of media, the attenuation due to dissipative effects obeys a frequency power law. By measuring the propagation of ultrasound signals through such a medium, the parameters that describe the attenuation can be estimated. In this paper a new method is introduced for estimating the attenuation of ultrasound media by means of transmission mode measurements. The method is based on analyzing the noise characteristics of the received signals and the formulation of a maximum likelihood estimator. The new estimator is compared to existing methods and was found to be a better estimator in terms of the RMS error than previous methods.
High-Output and High-Fidelity Microsized Driver System
Authors: Kim Keehoon , Xu Tao , Daniels Reginald
Published: May 2008

Active noise reduction (ANR) for aircrew hearing protection in harsh noise environments such as military and civilian flight operations requires a high-performance, microsized driver that provides not only high acoustic power, at least 130 dB SPL, but also high fidelity sound quality, especially in low-frequency ranges below 100 Hz. A new microsized smart material actuator (MSMA) is being developed by using high-density and direct-conversion piezoelectric exciters combined with a unique acoustic structure, unlike conventional moving coil/magnet-type drivers. The dimensions of the MSMA are 6 mm in diameter by 7 mm long, small enough for ear-canal application as an earplug driver, maximizing ANR effectiveness. The MSMA system consists of a microscale earplug driver, a protective package made of medical-grade stainless steel, and a compact actuation amplifier easily connected to or embedded in an external ANR controller. Performance tests show the system produces over 130 dB SPL in a 1 cc trapped cylindrical volume with very flat frequency responses even below 100 Hz. The total harmonic distortion of the MSMA is lower than 4% over all audible frequency ranges, without phase delay or discontinuities.
MEMS-based magnetic and electrostatic acoustic microspeakers
Authors: Pedersen Michael
Published: May 2008

Acoustic microspeakers remains a challenging application area for MEMS technology. This is mostly due to the inherently low transduction factors normally achievable in MEMS technology. While established electromagnetic transduction principles may be adapted for MEMS technology, there are also other transduction methods, such as electrostatic, with high performance potential. In this paper, the design, fabrication, and testing of two different types of MEMS microspeakers is presented. Firstly, an electromagnetic microspeaker is shown consisting of a MEMS diaphragm with integrated moving and an external rare earth permanent magnet and yoke structure. Secondly, a novel MEMS electrostatic microspeaker based on rolling contact is presented. In this device, high transduction forces are achieved by the strong electrical field over a solid insulator, and the forces are translated to a MEMS diaphragm by an integrated cantilever structure. Measurements on the electromagnetic microspeakers show a sensitivity of 83 dB SPL/mW at 1 kHz in a B&K 4153 acoustic coupler. The resonance frequency of the 6mm diameter diaphragm was 3.2 kHz. Numerical simulations suggest that simple changes to the moving coil geometry and material may increase the sensitivity to 108 dB SPL/mW.
Acoustic methods in extremely shallow water for reconstruction of ancient environments
Authors: Madricardo Fantina , Donnici Sandra , Lezziero Alberto , De Carli Federica
Published: May 2008

A large area of the Venice Lagoon was surveyed through a modified traditional echosounder. For the first time, acoustic methods together with geological analysis were used systematically to investigate natural and anthropogenic morphologies buried in the lagoonal sediments. The shallowness (with depths often < 1m) of the Venice Lagoon represents a challenge for underwater acoustic methods. The results we present in this paper show that such methods are very useful for detailed geomorphological and archaeological reconstruction and can be extended to other similar environments. In this context, a general methodology of multidisciplinary data collection was developed. As a synthesis of our acoustic and geoarchaeological investigation, maps of the ancient lagoonal environment were produced.
A surface acoustic wave impedance loaded sensor for wireless humidity measurement
Authors: Wang Rung-De , Chen Yung-Yu , Wu Tsung-Tsong
Published: May 2008

The control of humidity is required in various areas such as the smart living space, industry, agriculture, and medicine. To reduce cost and increase lifetime, a wireless humidity sensor without an additional power supply should be developed to fulfill their needs. Recently, there are more and more efforts on surface acoustic wave (SAW) based radio frequency identification (RFID) system. The RFID system primarily consists of a reader and transponders, composed of SAW tags and antennas. Due to the capabilities of passive operation and wireless connection, SAW tags are also suitable for remote sensing. Therefore, in this study, a wireless humidity sensor is accomplished by integrating a 433MHz 128°YX-LiNbO3 SAW tag with a resistive humidity sensor. The SAW tag is designed as an impedance loaded sensor. Moreover, because nanostructure sensing materials possess high surface-to-volume ratio, large penetration depth, and fast charge diffusion rate, CSA-doped polyaniline nanofibers are synthesized by the interfacial polymerization method and further deposited on the resistive humidity sensor as sensitive film to enhance the sensitivity. Finally, the humidity sensor was constructed and measured. Results indicate that our proposed sensor exhibits not only good linearity but also high sensitivity. Furthermore, it is indeed capable of passive remote sensing.
A study on the adaptive design of loudspeaker driver parameters for a given enclosure
Authors: Lee Seokjin , Noh Junguk , Sung Koeng-Mo
Published: May 2008

In the conventional methods of electro-dynamic loudspeaker design, driver units are selected first and then the enclosures are designed for the best compensation of frequency responses of the given drivers. However, in the industry of nowadays, these conventional methods are not appropriate; the enclosure design is determined first, and after that, a proper driver unit is selected by trial and error. In this paper, an adaptive design method of loudspeaker driver parameters for a given enclosure is studied. We estimated loudspeaker parameters such as diaphragm size, acoustic compliance, acoustic resistance, etc., to obtain an optimal alignment or desired response curve for a given enclosure. In the proposed method, the target frequency response curve in low-frequency range is determined first. Second, the optimal size of driver is calculated. The other driver parameters, such as driver suspension, Q of driver, etc., are designed lastly. Easier and faster design can be achieved by the proposed design method of electro-dynamic loudspeakers.
Application of Advanced Features in Computational Acoustics
Authors: Lerch Reinhard , Kaltenbacher Manfred , Meiler Martin
Published: May 2008

Modern numerical simulation tools allow the analysis of the generation and propagation of sound. However, a variety of computational features enhancing their applicability are missing in these codes. Therefore, it is sometimes cumbersome to come to practically useful results when applying such codes to real life problems. Here, some of these lacking features will be addressed and, furthermore, their implementation in a new finite element code is reported. These features are: Frequency dependent damping propagation medium, nonmatching grids for computing sound in neighbouring domains with quite different propaga-tion velocities and perfectly matched layers (for handling of open domain problems without reflections at boundaries of the computational domain). A finite element environment including pre- and post-processing has been established to support the development of electroacoustic devices. The following real life examples will be reported: electrodynamic loudspeakers, noise emission from power transformers, ultrasound devices for medical imaging such as conventional piezoceramic arrays as well as CMUTs (capacitive micromachined ultrasound transducers). It will be also shown that the code is able to handle nonlinear effects in transducing mechanisms and acoustic wave propagation, as occurring in HIFU (high intensive focused ultrasound) applications.
Computer tools for architectural acoustics education
Authors: Kang Jian
Published: May 2008

Calculating/simulating acoustic performance of architectural spaces and building elements plays an important role in architectural education. Unfortunately, architectural students often hesitate to use theoretical formulae/models commonly applied by acousticians. This study aims to develop simple calculation/simulation tools to help architectural students to understand basic acoustic principles. Focusing on the effectiveness of various key parameters, as well as on scientific visualisation way of presenting teaching materials, five tools have been developed: (1) sound distribution behind an environmental noise barrier, with parameters including barrier height, source-barrier distance, and source height; (2) sound distribution in a rectangular street canyon, with parameters including street length, width, building height, boundary absorption coefficient, air absorption, and the height of receiver plane; (3) reverberation time calculation in a rectangular space, with parameters including room dimensions and boundary absorption coefficients, where a database of absorption coefficients is also included; (4) absorption of perforated panel absorbers, especially micro-perforated panel absorbers, with parameters including hole size, hole spacing, panel thickness, and depth of airspace; (5) digital audio animation for urban soundscape design, considering idealised cross-streets and squares in a 2D environment, where the sound file with multiple sources can be played back, with reverberation effects. [Work supported by the Theodore John Schultz Grant]
Live computer-based demonstrations in musical acoustics education
Authors: Campbell Donald M. , Skulina David
Published: May 2008

Live demonstrations play a vital pedagogical role in any science education programme. For a subject as interdisciplinary as musical acoustics, embracing as it does mathematics, physics, engineering, psychology, cognitive science, neurophysiology, musicology and music technology, demonstrations of psychoacoustical phenomena and performances on musical instruments provide invaluable methods for involving and intriguing a general audience. The recent dramatic increase in the memory and speed of laptop computers has opened new possibilities for live computer-based demonstrations. This talk explores some of these possibilities, including demonstrations of the analysis and display of musical instrument sounds using real-time spectrographic programs and the explanation of important musical instrument characteristics using physical modelling synthesis.
Noise Metric - Environmental Noise Analysis Software
Authors: Stojiljković Milan , Delic Vlado
Published: May 2008

Noise Metric software suite addresses the need for a modern low-cost acquisition, post-processing and analysis system that accommodates professional grade instruments used in typical environmental noise assessments. Software is designed to comply with national and international legislation and to provide a comprehensive overview of environmental acoustics theory in an interactive help file. Educational use is emphasized by providing measurement wizards and example case histories, with included demonstration measurement files for student self study. Acknowledging tight student financial budgets, the system is not limited to use with professional grade equipment. It can be configured for less expensive and less precise operation by providing integration with standard PC sound boards and low-cost microphones. Current beta version focuses on community noise and traffic noise assessment, with future modules planned for occupational noise and basic acoustic calculations. Off line analysis module is supplemented by a real time module for recording and logging the measurements and a browser for viewing the analysis results, noise rating level calculation and report generation. Every attempt is being made to automate as many analysis tasks as possible and thus minimize the human induced errors in the assessment process. Preliminary product testing was successfully completed by comparison with proprietary software products.
Physical parameters of the violin bridge changed by active control
Authors: Boutin Henri , Besnainou Charles
Published: May 2008

The physical parameters of a violin bridge have a significant influence on the tonal colouration of its sound. The resonance peaks of the bridge shape the response of the violin body. Reinicke and Cremer developed a simple bridge model that shows a typical broad frequency peak around 2.5kHz, because it incorporates the coupling to the violin body and the soundpost. By using the same model, Jim Woodhouse revealed the effect of some parameters of the bridge (mass, stiffness and foot spacing) on the instrument frequency response. Here the parameters of the violin resonance peaks are changed in real time, by applying an active control method. Such a technique, very useful in noise reduction, enabled to change separately the position and the shape of each peak of the bridge input admittance. On the bridge, 2 actuators and an accelerometer are placed at strategic positions in order to change the peak frequency and the damping factor values. The system behaviour is controlled by a Digital Signal Processor. Some sound results achieved with a real violin back up the theoretical equations.
The guitar as an extension of the voice - Phonetic gestures underlying guitar timbre perception and description
Authors: Traube Caroline , Lavoie Maryse
Published: May 2008

The guitar is an instrument that gives the player great control over timbre. Different plucking techniques involve varying the finger position along the string and the inclination between the finger and the string. Guitarists perceive subtle variations of these parameters and have developed a rich vocabulary to describe the tones they produce on their instrument. Vocal imitations - onomatopoeias - is another way to intuitively describe instrumental tones. The data that we collected showed that guitar tones can be consistently associated with different types of vowels depending on instrumental gesture parameters, suggesting that guitar tones can evoke "phonetic gestures" as defined in the motor theory of speech perception. In addition, these phonetic gestures seem to be at the origin of a large subset of commonly used verbal descriptors: open, oval, round, thin, closed, nasal, hollow, etc. These analogies can be explained by the comb-filter shaped spectral envelope of plucked-string instruments which emphasizes energy in the region of vocal formants. We conclude that, when technical difficulties have been surmounted, performers can use their musical instrument as an extension of their voice, the musical instruments allowing a virtuosic control of sound parameters similar to those involved in the paralinguistic elements of speech.
The application of thin plate theory to the time evolution of musical instruments
Authors: Gorman Christopher , Parker David , Ballance Connor , Griffin Donald , Moore Thomas
Published: May 2008

The steady state dynamics of many musical instruments can be modeled using thin-plate theory. It has been shown that the normal-mode frequencies of systems as diverse as the orchestral crotale and piano soundboard can be accurately calculated within this approximation, and it is therefore reasonable to ask if thin-plate theory can be applied to model the time evolution of these instruments. To answer this question we have modeled a struck flat plate using finite differences and compared the decay of the eigenmodes to experimental results. We find that the time evolution of the motion of a struck thin plate is not well described under the thin-plate approximation even when the modal frequencies are predicted accurately. We propose that mode coupling between longitudinal and transverse modes requires that a full three dimensional model be used to predict the time evolution even when the plate is thin.
Categorization of guitars from bridge admittance measurements
Authors: Gautier François , Le Carrou Jean-Loic , Hol Maarten , Doutaut Vincent
Published: May 2008

The acoustical characteristics of the guitar depend on the instrument makers' choices concerning the geometry, the material and the assembly techniques. The aim of this paper is to define criteria permitting the discrimination of guitars according to their acoustic characteristics. These criteria can be used, for example, by instrument makers to test the repeatability of their making process. Evaluation of the guitars' quality from this categorization is beyond the scope of this paper. A low-cost portable system allowing bridge admittance measurements has been designed and used on 4 groups of classical guitars, each being composed of about 10 similar instruments. A statistical study shows that the tested instruments can clearly be differentiated according to (1) the modal parameters associated to the first 2 vibroacoustic modes (air mode A0 and first soundboard mode T1), and to (2) a 'merit indicator', close to the one defined by C. Barlow (Proc.I.O.A., vol 19, Pt 5, 1997, 69-78). This 'merit indicator' is computed from the mean value of the bridge admittance and an estimation of the critical frequency of the soundboard.
Sound quality of the 16'' french bagpipe: wood influence
Authors: Paquier Mathieu , Jeannin Raphaël
Published: May 2008

The most played among the bagpipes from the centre of France is the 16-inch musette, called in this way because of the length of the melodic pipe (oboe). Though these instruments are less known than the biniou from Brittany or the Great Highland Bagpipe, the number of players and makers is, nowadays, in increase because of their easy play and quasi-chromatic scale. Whereas the Breton and Scottish bagpipes are always made of very hard woods, some 16'' musettes are fabricated with softer woods. This difference is certainly related to the flexibility of the 16'' oboe double-reed. At first, we recorded some short musical sequences played on 16'' musettes made of 5 different woods (African Ebony, Santos Rosewood, Boxwood, African Blackwood and Service Tree), then some listeners (specialist and naïve) were asked to give their feedback about the quality of the recorded sounds. In a second set of experiments, we recorded some single notes played with these various bagpipes and analyzed the acoustic features of the recorded signals. At last, the perceptual results were compared with the physical parameters obtained in the second experiment.
A synthesis and analysis framework for wind instrument sounds based on the digital pulse forming principle
Authors: Oehler Michael , Reuter Christoph
Published: May 2008

A digital real-time-capable analysis- and synthesis-system for wind instrument sounds, based on the pulse forming theory, has been developed. The rediscovered model for the sound generating process of wind instruments rests upon the idea, that wind instrument sounds can basically be put down to its excitation impulses, which independently of the fundamental always behave according to the same principles. First realised in the analogue wind instrument synthesizer Realton Variophon (1975), the sound synthesis method has currently been transferred onto a digital platform [supported by the German Research Foundation]. Instrument specific algorithms control the pulse width and shape according to the applied pitch and dynamic values. That way subtle sound nuances that can be produced on acoustic wind instruments as well as real timbre modulation may be synthesized by just modifying a single parameter (i.e. breath pressure). In order to validate the performance of the developed framework, several perception experiments were conducted subsequently.
Fine tuning of guitar sounds with changed top plate, back plate and rim geometry using a whole body 3D Finite-Difference model
Authors: Bader Rolf
Published: May 2008

The change of radiated sounds from guitars is investigated in terms of the fine tuning of these sounds applying slight changes to the guitar body, instrument builders would do with their guitars. As changes of these geometries of real guitars can only be perceived when the instrument is put together, the question is mostly open how different the whole instrument would have sounded with slight changes. So here the virtual guitar can be of great use. In the model, the top plate thickness, fan bracing, rim thickness and back plate geometry were changed in a linear way. Then these results could be associated directly to a change in only one geometry parameter. It is not assumed, that the sounds fit one existing guitar perfectly. Rather th overall influence of these changes on the sounds is investigated to show an overall behaviour. As the eigenfrequencies of the guitar body are that many, that a more or less closed resonance curve is achieved (without so-called 'dead spots'), the changes in the sounds are measured in the following terms: changes in the initial transient of the sounds, its brightness using the spectral centroid, its density using a spectral entropy measurement and amplitude fluctuations of the different sound partials.
Cross-modality matching of loudness and whole-body vibration strength
Authors: Töpken Stephan , Bellmann Michael , Weber Reinhard
Published: May 2008

In every day live humans are often exposed to noise and vibration simultaneously. Regarding comfort issues inside a car, it is of interest to know, whether the simultaneous perceptions of noise and vibration interfere. Laboratory tests have been carried out with temporally overlapping, partially overlapping and non overlapping presentations of acoustic and whole-body vibration stimuli. Sitting on a rigid chair on a vibration test bench, participants are asked to judge the strength of the excited whole-body vibrations in comparison to the loudness of noise presented via closed headphones. An adaptive method is employed to determine the subjective point of equality (PSE) between both sensory channels. The acoustic stimulus is a 1/2-octave band-pass noise centred at 100 Hz with a fixed noise level, the vibration stimulus is a narrowband noise, also 1/2-octave broad with a centre frequency of 31,5 Hz. The signals have an equal duration of one second. The signal parameters are chosen with respect to specific situations in a car. The PSE's of the loudness and the vibration strength as a function of the temporal order of the acoustic and vibration stimuli exhibit no dependency on the degree of temporal overlap of the stimulus presentation.
Aural Connectivity: Enhancing sound environments in critical care settings for effective nurse auditory monitoring
Authors: Okcu Selen , Zimring Craig , Ryherd Erica
Published: May 2008

In intensive care unit (ICU) settings, the sound environment is critically important to nurses accomplishing their tasks. In earlier studies by the authors, it was found that non-amplified environmental sounds such as patient bodily sounds, patient threatening/unusual sounds, and help calls from patients and other caregivers are critically important auditory cues that nurses must listen for and respond to immediately. These sounds do not exist in isolation but matter as a pattern of aural connectivity that can support a nurse's critical monitoring abilities as she moves through her workplace. Aural connectivity is a network measure that reflects the overall pattern of where users can hear and respond to different key sounds within a setting. This paper describes the sound environments of two ICU hospital settings with similar patient acuity levels but differing layout designs. Preliminary results regarding the patterns of aural connectivity and the role that layout design might play in those patterns are discussed and potential implications for layout design are proposed.
Generic noise criterion curves for sensitive equipment
Authors: Gendreau Michael L.
Published: May 2008

Electron beam-based instruments are sensitive to the environment in which they operate. Adverse environments may limit their achievable resolution. Many equipment manufacturers provide specifications for the acceptable level of various environmental conditions, such as vibration, EMI, and acoustic noise. However, the quality of the specifications vary significantly, from well-defined to conjectural. Additionally, during the design of a facility, the specific instruments that will be used may not yet be known. Thus, it is useful to have "generic" criteria, intended to represent entire classes of instruments, to use in the design of facilities. Generic vibration criteria exist to aid in the design of laboratories, though there have been no such instrument-based generic criteria available for acoustic noise. The generic noise criteria that are currently used in lab design (NC, NR, dBA, etc.) were established to address the effect of noise on human beings. Using noise specifications for a significant number of instruments with varying resolving powers, correlation of resolution with environmental noise is demonstrated. Based on the data reviewed, generic noise criterion curves have been developed and presented for use in the design of facilities that contain noise-sensitive equipment. These are applicable when other well-defined and specific criteria are not available.
Noise exposition in the daily life
Authors: Romero José , Giménez Alicia , Cerdá Salvador , Navasquillo Joaquin , Lacatis Radu , Barba Sevillano Arturo
Published: May 2008

Nowadays, the man lives exposed in a world of sounds (pleasant - disagreeable, nonannoying - annoying) throughout the time, during the 24 hours a day. The man is exposed to the noise in his daily life, since he awakes, moves, works, entertains itself, rests, and to sleep. We have made a survey of levels of exhibition to the noise, having distinguished they are leisure, work or rest, in a amog young population of 20-35 years without hearing problems, and of both sexes. The results show us and agree with other authors, that the exhibition levels are highest in the activities chosen, like for example the leisure. In addition, the levels of exhibition, to the noise are related with the diverses activities of the population.
New vehicule noise emission values to update the French 'Guide du bruit'
Authors: Doisy Sonia , Lelong Joel , Hamet Jean-François
Published: May 2008

French traffic noise prediction models are based on vehicle noise emission values defined by the "Guide du Bruit des Transports Terrestres", issued in 1980. A research programme was established in order to update these values and take into account developments in car and road technology. The methodology followed to output emission values has been developed by successive steps, as the processing performed on the collected data went along. After several attempts the shape adopted for the emission formulas considers the vehicle pass-by LAmax as the sum of two subsource contributions: the power unit contribution which varies with acceleration and the road gradient, and the tyre/road contribution which varies with speed and the road surface type. New emission values are now completely defined, and ready to be used in noise prediction models.
Statistical energy analysis limits for acoustic radiation car: an alternative approach
Authors: Borello Gérard , Borello Alex , Primus Julien , Gagliardini Laurent
Published: May 2008

Due to a new pass-by noise regulation, Vehicle exterior noise will have to be reduced in the coming years. This may be achieved by optimizing underbody and underhood absorption and screening apertures. There is then a need for numerical techniques able to predict sound reduction related to acoustic absorption and transmission loss changes. Through a work supported by ADEME and headed by PSA, energy-based predictive techniques such as Analytical Statistical Energy Analysis (ASEA) and discretized Energy Flow Analysis (DEFA) were tested against the actual physical problem to be solved through a series of benchmarks. Both theories are compared across several simple acoustic problems. It is concluded that both methods do not fit to the initial acoustic optimization requirement due to their intrinsic assumptions that restrict their applicative range. More fitted numerical techniques are now investigated: among new candidates, the Virtual SEA (VSEA) technique that allows the creation of a numerical model of coupled acoustic cavities from the finite element global modes without the serious limitations of ASEA and a matrix approach based on Craigh-Bampton substructuration of the cavities.
Noise reduction in an operating room: A case study
Authors: West James , Busch-Vishniac Ilene , King Joseph , Levit Natalia
Published: May 2008

In our previous study reported in INTER-NOISE 2006 we found that operating rooms are among the most problematic areas in the healthcare industry. The maximum peak levels measured during various surgical procedures are extremely high - 100-120 dB, which can potentially lead to the hearing damage and interfere with the speech communication during surgery. Neurosurgery and orthopedic operating rooms are found to be among the noisiest overall. However, introduction of the acoustical materials to the operating room is very difficult due to the strict infectious control requirements. We report here a case study on using sound absorptive panels protected by DuPont Tyvek®, a unique flash spun plexifilamentary film-fibril sheet, combining excellent barrier properties with distinctive porous structure to make it acoustically transparent in the voice frequency range.
New findings on noise exposure in the construction trades
Authors: Paulsen Reimer
Published: May 2008

The degree to which employees on construction sites are exposed to noise often depends on a variety of individual activities. The calculation of the average noise exposure for different construction trades in this sector calls for an enhanced level of work analysis and measurement. Recommended here are personal measurements with simultaneous recording of the various activities and machines employed. With the subsequent assignment of average sound pressure levels and activities, it is then possible to draw conclusions about part exposures and mean exposure. At euronoise 2006 in Tampere, findings for a series of construction trades were presented. In the meantime, this series of measurements has been extended to include further trades. Furthermore subsequent measurements have been performed for individual trades, this was considered necessary because certain machines and working methods have changed in these fields in the last 20 years. The findings show that technical progress does not necessarily result in a reduction in noise exposure.
Overview of revolutionary aircraft for quiet communities workshop
Authors: Posey Joe W.
Published: May 2008

At some time in the future, technical advances, environmental imperatives, societal expectations for mobility, and economic drivers will dictate that radically different aircraft will be built and flown. Therefore, aircraft designs will change even if low noise were not one of the environmental imperatives, and acousticians must be aware of the possible directions for aircraft design and the resulting opportunities and challenges for noise control. To address this need, the National Aeronautics and Space Administration sponsored a workshop entitled Revolutionary Aircraft for Quiet Communities in Hampton, VA, 24-26 July 2007. Twenty-six talks covered aircraft design, interior noise challenges, airframe noise, propulsion, and aircraft noise prediction. Revolutionary aircraft will employ dramatically improved materials, propulsion systems, and flow control technology to improve efficiency and enhance mobility. Five hours of discussion surfaced many concerns and recommendations, including the increasing need for acousticians to be involved on highly integrated teams throughout the vehicle design process. Also, other discipline experts participating in aircraft design need some education in acoustics to increase their sensitivity to noise control issues. The National Institute of Aerospace hosted the event, and the Council of European Aerospace Societies and the American Institute of Aeronautics and Astronautics were co-sponsors.
Noise masking as a soundscaping measuring procedure
Authors: Boubezari Mohammed , Bento Coelho J. Luis
Published: May 2008

Loudness is the perceived intensity of a sound that could solve the problem of measuring a sound that is already filtered by the listening procedure. However, technically it is impossible to separate physically the sources of a noise into its components as well as human perception does. Loudness cannot be operative if a sound is merged with other noises. The principle of the proposed solution consists on gradually mixing a white noise during listening until the selected sound that one wants to measure is totally masked. The level of the masking white noise is controlled independently from the listener and measured with dB(A). The listener controls the limit of audibility of the selected sound, which is masked by the white noise. This paper describes the patent deposited around this method and shows the results obtained so far, and how this technique can be helpful in a visual translation of the sound space composition.
Adaptive Characterization of Near and Far field Elements in the Soundscape
Authors: Barclay David R.
Published: May 2008

Characterization of a soundscape through objective parameters relies on our understanding of psychoacoustics and ability to model the complex signal processing of the mind. Certain physical parameters such as loudness and timbre are easily retrieved from data while other descriptive parameters are more difficult to measure objectively. Several signal processing algorithms are presented here in the context of describing a soundscape in terms of keynote sounds (background noise) and sound signals (foreground sounds). Simulations and stereo field data recorded in San Diego are analyzed. Adaptive matched field processing is used in conjunction with conventional spectral analysis for the detection and categorization of near field events. These sounds are then removed to provide a more accurate description of keynote sounds. Spatial distribution of the soundscape is measured using conventional beamforming algorithms.
Internet and mobile technologies for a public role in noise surveying
Authors: Mydlarz Charlie , Drumm Ian , Cox Trevor J.
Published: May 2008

The traditional method of noise surveying is to use trained professionals to go to a specific site to measure and assess noise levels using dedicated and expensive equipment. This project aims to enfranchise the public by providing them with the opportunity to play an active role in noise measurement and assessment, as well as how their soundscapes are shaped. With the implementation of mobile phone, PDA and PC applications, alongside web based collation techniques; we aim to empower the public in the gathering of context specific data on soundscapes. The methodology will provide a case study for the wider research community in developing public participation-based research activities of this kind. This will provide a better understanding of the public's relationship with their soundscape and how this relationship varies with location and demographic data. Inferences will be compared from the analysis of data sets generated with other soundscape research with a view towards validating the techniques and gaining new insights into the field.
From Descriptive to Predictive Soundscape Representation
Authors: Boubezari Mohammed , Bento Coelho J. Luis
Published: May 2008

Regarding the knowledge on psychoacoustics (Zwickers), on phenomenology of perception (Gibson. J. J.) and the results obtained at CAPS-IST (Boubezari-Bento Coelho), a descriptive and qualitative sound map was drawn and a predictive procedure was developed. The method shows that the introduction of human perception during the process of analysis and signal processing makes it possible to target measurements on one or more noise sources selected separately from their background noise. Contrary to conventional measurements, which yield overall values of LAeq, without distinguishing the sources, the method presented here allows a space description of a sound space by making each sound stand out from its context. The method allows the measurement of the range of a noisy source in a given place, the testing of the range or the masking of an urban device (fountain) or contribute to the decision and the design of a specific architectural project, for example. This paper describes the method (and its limits) and the results obtained and shows how a predictive qualitative sound map with low cost is now feasible.
Wind farm aural and visual impact in the Netherlands
Authors: Van Den Berg Frits , Pedersen Eja , Bakker Roel , Bouma Jelte
Published: May 2008

The WINDFARM perception project, carried out in 2006 in the Netherlands, aimed to explore the impact of wind farms on people living close to wind farms. The study sample was selected in three types of area (countryside, countryside with major road, built up area) by means of a Geographic Information System (GIS). Each selected address was within 2.5 km of a wind turbine of at least 500 kW electric power and a similar turbine within 500 m of the first. Aural impact was calculated according to three different sound propagation models: the international ISO-9613 standard, the model legally required in the Netherlands, and a simplified model as in the New Zealand Standard NZS-6808. Visual impact was quantified in two ways: the vertical angle determined by the height of the apparently tallest turbine, and the solid angle determined by all turbines where each turbine was replaced by a vertical rectangle just enclosing the turbine. Immission sound levels from the wind farms at 1948 receiver locations varied from 21 to 54 dB(A), relative size from 0.01% to 30% of the total field of view. Results show that all impact measures are highly correlated with distance to the nearest wind turbine.
Methods for automating prominent tone evaluation and for considering variations with time or other reference quantities
Authors: Bray Wade R.
Published: May 2008

Information Technology acoustic protocols include identifying prominent tones according to likely subjective importance. Most existing methods for calculating tone-to-noise ratio (TNR) require a suspect tone to be selected by the analyst, who must also mark the width; both are potential sources of uncertainty and variability. One purpose of this paper is to present an automatic tone-detection and width-assessment methodology for more robust, less operator-intensive TNR calculation in accordance with ECMA-74. The paper will also present a process giving a complete spectral representation of the prominence ratio (a specific prominence ratio) by iterating the calculation at each frequency bin of the Fourier transform of the time-signal. The ECMA-74 tone-detection procedure for TNR is also applicable to the specific prominence ratio and is automatable, yielding tones-only prominence results without user intervention for any or all tones qualifying as prominent. The conventional average prominent tone evaluation over an operating interval can cause mis-assessment or no assessment of subjectively prominent tones which change frequency and/or level with time. We will therefore also discuss applying the described procedures as functions of time or other reference quantities, and suggest considering the subjective significance of time-domain effects such as modulation occurring from certain multiple prominent tone situations.
Dense road surfaces with small aggregate size - tyre/road noise reduction after repaving
Authors: Nilsson Nils-Åke , Ulmgren Nils
Published: May 2008

Open, porous road surfaces normally suffers from pore clogging particularly in inner city situations with low vehicle speed. After a relatively short time pore clogging could almost eliminate the noise reduction effect. A dense low noise road surface with smaller aggregate stone size could here offer substantial noise reduction due to reduced surface roughness, despite its low sound absorption factor. In this paper is presented data on the "repaving insertion loss" in dB(A) when exchanging a worn older SMA16 by a newly paved dense SMA8. Comparative results will also be shown for various types of newly paved SMA16 in comparison to the a newly paved SMA8. The technique for noise reduction mentioned above could be believed to have an "improved long term endurance" as compared to the same degree of noise reduction achieved by open graded technique particularly in city centres. For the Scandiavian countries where studded tyres are allowed, further reduction of stone size could be possible at acceptable wear rate if studded tyres are taxed or prohibited e.g. in environmental zones. This could lead to a further increased reduction of tyre/road noise in such zones. Grant from European Commission to Project Quiet City Transport (QCITY) is acknowledged.
Measurement of pavement absorption using ISO 13472-2
Authors: Seybert Andrew F. , Han Jun
Published: May 2008

This paper discusses some recent experience with ISO draft standard 13472-2 for the measurement of the absorption of pavements. The draft standard is meant to be used for the measurement of the sound absorption coefficient of "reflective" pavements, e.g., pavements of test tracks used for passby noise measurements of vehicles, tires, etc. An impedance tube has been constructed based on the requirements of the draft standard, and the device has been used in the laboratory (with pavement samples) and in situ to measure pavement absorption. The papers discusses these results and other important features of the draft standard including microphone calibration, parasitic tube absorption, and the construction features of the impedance tube and source.
Inversion of the bulk viscosity in nonequilibrium media with heat release and new acoustical properties of such media
Authors: Molevich Nonna
Published: May 2008

New acoustical properties, which are caused by the inversion of the bulk (second) viscosity in nonequilibrium media, are investigated. Negative bulk viscosity can take place due to the positive feedback between the sound perturbation and the nonequilibrium heat release. During previous years, the conditions for the negative bulk viscosity existence were found in a large number of nonequilibrium media such as a vibrationally excited gas with stationary nonequilibrium, nonisothermal plasma, chemical active mixtures with irreversible reactions, media with nonequilibrium phases, upper atmosphere layers, and earth magma with bubbles. The following phenomena are discussed for gaseous media with negative viscosity: (1) New dispersion characteristics (in particular, the low-frequency sound speed can exceed the high-frequency one); (2) Acoustically instability of nonequilibrium media, nonlinear mechanisms of the wave growth stabilization and stationary self-sustaining structures; (3) Linear and non-linear sound beam refraction including the self-focusing (due to two self-action mechanisms in acoustically active media: the gas cooling by sound and the excitation of acoustical streaming in direction opposite to sound propagation) and the anomalous reflection (with reflection coefficient R>1) on a boundary between equilibrium and nonequilibrium media; (4) The vortex and thermal wave amplification due to intensive parametric interactions in acoustically active media.
Acoustic studies of the martensite phase transition in Ti-Ni alloys
Authors: Abramovich Andrew A. , Charnaya Elena V. , Belyaev Sergei P. , Volkov Aleksander E.
Published: May 2008

Acoustic studies of elastic properties and attenuation of ultrasonic waves (longitudinal and transverse) at the martensite phase transition were carried out in the Ti-Ni based polycrystalline alloys. Measurements were carried out using a pulse ultrasonic technique within a temperature range of 190 to 440 K upon continuous warming and cooling the samples after various hardening and annealing treatment. Anomalies of ultrasound velocity and attenuation were observed through the martensite phase transition which depended on wave polarization and thermal history of the samples, peaks of attenuation were seen only for transverse waves. A pronounced thermal hysteresis of acoustic features was also observed upon warming and cooling. The obtained results were treated on the basis of the phenomenological Landau theory for the B2-B19' ferroelastic phase transition.