bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrorheological fluids and possible applications to absorbers of underwater sound
Authors: Wicker K. , Eberius C. , Guicking D.
Published: October 2005

Electrorheological fluids (ERF) show a large variation of their viscoelastic properties in a strong electric field. Applications suggested so far aim at electrically controllable clutches and hydraulic shock dampers. A new field of ERF applications is underwater sound where the construction of absorbers with electrically adjustable properties appears possible. These two fields of applications differ in the frequency and strain ranges: The mechanical (macroscopic) applications exhibit large strains at low frequencies, the acoustical systems small strain at higher frequencies. This is not a trivial difference due to the nonlinear behavior of the ERF. Experimental results will be presented on sound velocity and absorption of selected ERFs in a wide range of frequency, temperature, and electric-field strength for sound propagation parallel and perpendicular to the electric field. It turns out that, e.g., a temperature-induced shift of the absorption coefficient can be compensated, within certain limits, by an enhanced electric field. Preliminary results obtained with a laboratory setup of an absorber with transformed ERF particle velocity will also be presented.
Development of floor impact sound insulation technology in Japan
Authors: Kimura Sho
Published: October 2005

With the formulation of sound insulation performance standards by the Architectural Institute of Japan in 1979, the sound insulation ratings for floor impact sound level determined by means of the heavy and soft impact source stipulated by JIS have been used for performance orders and labeling for buildings in general. Furthermore, prediction calculation methods for sound insulation ratings based on the impedance method have also been developed. This has led to an increase in the thickness of standard floor slabs in concrete apartment houses in Japan from 110–120 mm at that time to 150–160 mm and, recently, there are many floor slabs that are as thick as 200 mm, thereby greatly contributing to an improvement in floor impact sound insulation performance. Meanwhile, there has also been progress in research dealing with the improvement of the insulation performance of heavy floor impact sound in wooden buildings. Unitizing highly rigid floor panels and beams and increasing the flexural rigidity of the overall floor cross section, while designing sound-insulated ceilings of the lower storey independent of the floor structure and the independent walls of the room below, have made it possible to achieve the performance of a concrete slab about 150 mm thick.
Assessment of low-frequency footfall noise in wood-frame multifamily construction
Authors: Blazier Warren E.
Published: October 2005

The impact insulation class (IIC) rating of floor/ceiling constructions fails to identify low-frequency footfall noise problems common in contemporary wood-frame multifamily construction. Because the IIC procedure ignores the impact noise spectrum below 100 Hz, the rating is not influenced by the low-frequency impact spectra produced by a typical live-walker, which usually peak in the region of 15 to 30 Hz and are associated with the ‘‘thuds’’ and ‘‘thumps’’ commonly observed. Data comparing the shape of the typical low-frequency impact noise spectrum produced by a live-walker and that of the standard ISO tapping machine indicate that the tapping machine might potentially be used as the basis for obtaining low-frequency impact noise ratings [W. E. Blazier, Jr. and R. B. DuPree, J. Acoust. Soc. Am. 96, 1521–1532 (1994)]. However, a comparison made between the two sources in the range above 100 Hz shows significant differences in the spectra produced by the tapping machine and a live-walker. This suggests that a more meaningful IIC rating of mid- to high-frequency impact noise might be obtained by cushioning the tips of the hammers in the standard ISO tapping machine, in order to better align the impact spectrum with that of a live-walker.
Floor research project at NRC Canada: An update on progress—Airborne sound and standard tapping machine measurements
Authors: Warnock A. C. C.
Published: October 2005

The extensive research project on sound transmission through floors is still in progress. This paper will present information on standard measurements made according to ASTM E90, ASTM E492, and ISO 140 parts III and VI. Since the last report in 1995, the effects of changing joist length, joist spacing and depth, wood I-beam type and depth, and the effect of adding concrete as a topping on the floor have been studied. Different types of subfloors and different types of gypsum board have been used in several combinations. For a given basic structure, the mass of the panels has the most effect on the single number ratings, STC and IIC, which are determined mainly by the sound transmission loss values around 125 Hz. Many structural changes have little effect around 125 Hz so STC values do not change much, although there are significant changes at other frequencies.
Prediction of heavy weight impact sound of large-spanned slabs
Authors: Koga Takashi , Tano Masanori
Published: October 2005

Adaptation of the large-spanned RC slabs, whose area corresponds to an apartment unit, is increasing in Japan. The authors measured heavy-weight impact sound and impedance of such large slabs at over 30 sites. The structural methods of slabs are: unbond, half-precast concrete, void, and the conventional framework method. There were no distinctive differences among structural methods except in case for void slabs. The impact sound level was determined by the thickness of the slab rather than the area of the slab, even if the area of the slab was over 70 m2. In the case of small slabs, where the first eigenfrequency of the slab vibration is around the 63-Hz octave band, there is a tendency of a high-impact sound level. On the other hand, the lower first eigenfrequency may be a benefit for the impact sound level. The stiffness level of the beam seem to depend on frequency.
Stimulus factors in perceptual confusability of tactile speech stimuli
Authors: Weisenberger Janet M.
Published: October 2005

One possible limiting factor in performance by users of tactile aids for speech perception is the high confusability of tactile speech stimuli. This paper summarizes results of several experiments designed to identify the physical characteristics of tactile speech signals that make two stimuli seem perceptually confusable. First, sets of nonsense syllables were recorded onto digital audiotape and presented to subjects in an identification task. These same stimuli were input to a computer simulation of a multichannel vibrotactile speech aid, the Queen’s vocoder, showing the level of activity in each of the 16 vocoder channels over the duration of the stimulus. Perceptual confusion matrices obtained from the identification task were compared to matrices of temporal and spatial coincidences of physical activity in corresponding channels for each stimulus. In further experiments, tactile reception of individual nonsense syllables was compared to degraded auditory perception of the same stimuli. Several different methods of auditory stimulus degradation were employed, including reducing the number of vocoder channels and temporal distortion (smearing). Results are discussed in terms of insights into the processing of complex, spatially distributed vibrotactile stimuli, as well as implications for modifications of tactile aid processors and displays to improve stimulus identifiability. [Work supported by NIH.]
A proposal of a new display method for the tactile voice coder: Usage of the swept convex pattern
Authors: Wada Chikamune , Ino Shuichi , Ifukube Tohru
Published: October 2005

A fingertip tactile vocoder for the deaf, has been designed, which has a vibrator matrix with 4×16 pins. A sweeping display method was proposed so that the stimuli were moved from right to left on a fingertip surface like electric news tape. From the experimental results, it was proven that an identification rate of the seven Japanese monosyllabic voices increased and reached 55% at a sweep speed of 10 cm/s. Furthermore, in order to improve identification rate, the usage of the convex pattern like Braille has been proposed, in addition to the sweeping display method. It was found that the identification rate of the seven Japanese monosyllabic voices increased by combining the convex pattern with the vibratory pattern, and the increment was about 20%, even though training period was 30 min. From the above results, it was concluded that the usage of the swept convex pattern besides the swept vibratory pattern was effective to increase the identification rate of speech. [Work supported by the Ministry of Education, Science and Culture, Grant-in-Aid for Scientific Research (A)(2) No. 06402067.]
Measurement of physiological and psychological responses during exposure to low-frequency whole-body oscillations
Authors: Takarada Naonosuke , Takesada Masashi , Hosoda Ryusuke , Arima Masakazu
Published: October 2005

Human responses to low-frequency whole-body oscillations were measured using a ship-motion simulator. An electroencephalogram (EEG), an electrocardiogram (ECG), perspiration, face-surface temperature, facial expressions, and the respiration of subjects were measured as physiological effects, and ride quality and motion sickness symptoms as the psychological effects. Before and after exposure to the oscillations, subjects were asked to reply to questionnaire surveys prepared to measure the psychological changes, to take blood samples, and to have blood pressure and sense of balance inspections. Measured results of physiological changes such as EEG, ECG, etc. have been analyzed by means of spectral analysis, wavelet analysis function analysis, and so on. The results of the questionnaire survey of the semantic differential method (SD method) were analyzed by introducing fuzzy integral and fuzzy measures as well as the traditional statistical method. Correlation analyses using all the measured results were carried out. From the results of analyses, it has been made clear that (1) subjects are classified into several types, and (2) psychological effects are important to evaluate the motion sickness incidence and ride quality, for example.
Stability of man gazing at a moving picture
Authors: Takada Hajime , Ohba Motoki
Published: October 2005

This paper is concerned with movements and stability of a man gazing at a moving picture in a darkroom. These experiments were studied to clarify the relation between visual information and postures. A worker may indirectly be exposed to vibration when the objects around him swing, for example by an earthquake. This is not only a problem for workers but also, when he operates a large plant, it is a problem for the system if he operates it erroneously. The bar picture was made with a computer and swings right and left in front of a subject in the first case, and, in the second case, the bar pictures start suddenly to the right side or to the left side and, after a constant time, they suddenly stop. As a result, one may stand more unstably under the following conditions: when the bars suddenly move or stop and when the equilibrium line of the bar vibration deviates right or left than when the line exits in the constant position. A man can stand more stably after a few trials than at the first or second trial. A man can swing his center of gravity when the bar swings in front of him. The picture is different from that which can make him unstable.
Whole body vibration on fast moving trains
Authors: Rasmussen Gunnar
Published: October 2005

A series of measurements has been carried out on trains in order to determine the comfort level for crew and passengers. Different trains and varying rail sections were evaluated at train speeds of 120 to 180 km/h. The main problem area is the comfort of standing persons and especially the crew. The measurements were carried out sampling the time varying signal from an x-y-z transducer mounted directly on the floor. The measurements were carried out from 0.1 to 100 Hz and stored directly onto a PC hard disk for later processing. The processing was carried out according to ISO 2631 and ISO 8041. Having the raw data signal available enables one to process the data using different time constants and weighting curves as well as root-mean-square and fourth-power values. A linear integrated value of the entire duration of a trip has little correlation with the perceived comfort. A subjective evaluation using a group of standing people judging their comfort level, on a 5-stage scale from very comfortable to very uncomfortable, shows good agreement with the running rms acceleration level using a 10-s time constant. The lateral exposure level in the Y direction (90° to direction of travel) for a comfortable ride was 0.4 m/s2.
Numerical and experimental study of radiated fields of high-power ultrasonic transducers for industrial applications in gases
Authors: Campos-Pozuelo C. , Lavie A. , Dubus B. , Rodriguez-Corral G. , Gallego-Juárez J. A.
Published: October 2005

Flexural axisymmetric vibrating plates with an extensive surface and stepped profile have been shown to be very useful high-power ultrasonic radiators. In fact, the stepped profile provides a highly directional or focused radiation which makes them highly efficient for gases and interphase applications. In this work we present a numerical–experimental study of the displacement distribution and the radiated field of various transducers (directional and focusing transducers working at different frequencies). The numerical model is based on a mixed finite element-boundary element method. The method basically consists of calculating the distribution of displacements of the transducers by the finite element method by using the code ATILA while the corresponding radiated field is calculated by the boundary element method by means of the code EQI. The influence of the loading medium on the displacement distribution is also calculated by the boundary element method. In this way the near and far field of the transducers is calculated as well as their directivity pattern and vibration distribution. The results obtained are compared with experimental data.
Development of bubble breaking equipment by aerial ultrasonic waves
Authors: Iwata Hisao , Nakamura Sueshige , Abe Sadahiro , Ito Yasushi
Published: October 2005

In a filling machine for carbonated drinks, many bubbles are generated, causing the vessels to overflow. As a result, only a small volume of drink is left in the vessel, and the vessel is dirtied. For breaking these bubbles, some bubble breaking methods were investigated experimentally. Finally, it was discovered that the method using aerial ultrasonic waves was the best of all for the filling machines. A bubble breaking machine utilizing aerial ultrasonic waves has been developed. It consists of an ultrasonic vibrator, a metallic horn, a rectangular plate, partition plates, and a reflection plate. The rectangular plate is designed to vibrate in the stripes mode, which is the most efficient radiation mode. The partition plates are set perpendicular to the node lines of the stripes mode, so many pistons are produced by the partition plates. The reflection plate concentrates sound radiation from one piston at one particular point. The equipment was applied to a filling machine of carbonated drinks and the desired results were obtained.
Vibroviscometer using a triangular bimorph transducer
Authors: Kobayashi Tsutomu , Tai Hidekazu , Ueha Sadayuki
Published: October 2005

A new vibroviscometer is proposed, and it was fabricated in order to prove its feasibility. The viscometer consists of a triangular bimorph transducer and a circular thin plate. The bimorph transducer consists of two piezoelectric plates and a metal shim plate, and the shim plate is sandwiched in between the piezoelectric plates so that two pairs of piezoelectric–metal-plate (unimorph) transducers can be used separately as driving and detecting transducers. The circular plate is adhered on the acute tip of the triangular transducer at a right angle to the transducer surface. As the measurement procedure, only the circular plate driven by one unimorph transducer is immersed in the liquid and the output of the other unimorph transducer is monitored to be compared with the driving signal. It was found that the difference in the electrical phase between the driving and the monitored signals appears to be in proportion to the viscosity of liquids and that the difference remarkably appears at the range of the antiresonance frequency between the first and the second resonance frequency of the triangular bimorph. The reason for this is that the viscosity of the liquid exerts a retarding force on the plate. As for the results of the experiments regarding the frequency characteristics, the temperature characteristics, and the measurement of the viscosity for many liquids, it was proved that this phase difference method using the triangular bimorph can be used successfully for precise measurements of the viscosity.
Filtration technique enhanced by electro-acoustic methods
Authors: Tuori Timo , Järvelä Eliisa , Sekki Hannu , Mursunen Hannu , Väärämäki Tuulia , Heikkinen Juha
Published: October 2005

Results from an experimental study of electric and/or ultrasonic field assisted filtration are presented. Both electric and ultrasonic fields can reduce fouling of the filtration medium and have significant influence on filtration capacity. The extent of filtration improvement is affected mostly by particle size, surface charge, acoustic frequency, and field strengths. Theoretical examinations of the use of electric field and/or ultrasonic field to enhance filtration efficiency were laid out. Some aspects regarding orthokinetic interaction in acoustic agglomeration were considered. Energy consumptions of the filtrations of different suspensions used in experiments were also determined. For pyrite suspension the best results with ultrasound were obtained when filtration was done as follows: 15-s negative pressure filtration, 15-s negative pressure filtration with 22-kHz ultrasonic burst (0.5 s) and 20-s drying with negative pressure. In this case the moisture content of cake was 7% while in the reference cake it was 14%. The cake capacity was fourfold greater than in the reference case. The best results for phosphoric acid were obtained when combined use was made of the ultrasound and the electric field. In this case the filtration capacity increased fifteenfold while the use of ultrasound on its own increased the filtration capacity tenfold.
Laser ultrasonic evaluation of solder connection in integrated chips
Authors: Smith Jerry Rosson
Published: October 2005

Currently, no on-line techniques exist for the inspection of solder connections in surface mount technology (SMT) chips or in flip chips. This research investigated the use of laser-induced ultrasound in test chip samples to determine solder joint integrity. The ultrasonic vibrations were detected interferometrically and analyzed to determine chip mounting quality. Analysis was conducted in both the time and frequency domains. A controlled sample of flip chips, several (unidentified) of which were processed in a manner that tended to create poor connections, were tested and the vibrational signatures were compared. Comparison of the vibrational signatures showed a single flip chip with an abnormal signature. Detailed visual inspection demonstrated that the suspect chip was indeed poorly connected. Tests involving SMT consisted of obtaining the signatures of chips with high-quality connections. These connections were systematically damaged to simulate poor joints. Signatures were then taken from the newly damaged chips and compared with the undamaged signatures. Physical models and interpretations concerning experimental results have been developed. Future phases of research are outlined, including other promising results and capabilities. [Work supported by PRC.]
Driving circuit of vibratory gyrosensor using damped capacitance elimination techniques
Authors: Sakurai Katsutoshi , Satoh Akira , Ohnishi Kazumasa , Tomikawa Yoshiro , Kusakabe Chiharu
Published: October 2005

In a vibratory gyrosensor, a high-quality factor and no frequency difference between driving and detecting frequencies are necessary to construct a high-sensitivity gyrosensor. In order to adjust driving and detecting frequencies and driving position of the resonator in the gyrosensor, mechanical trimming, which means the partial cutting toward the resonator, is effective; however, such a trimming is complicated. For a method of electrical changing of the resonance frequencies of the resonator, it is well known to insert a condenser between the driving circuit and the driving electrode of the resonator; however, that method is usually used for a slight adjustment of the resonance frequency. On the other hand, a method was devised to change the resonance frequency of the piezoelectric vibrator, using damped capacitance elimination techniques, and it was utilized to a driving circuit of the vibratory gyrosensor. In this paper, sensitivity characteristics of the gyrosensor, whose driving frequency is changed using the damped capacitance elimination circuit, are reported.
Piezoelectric vibratory gyrosensor using a trident tuning-fork resonator
Authors: Satoh Akira , Tomikawa Yoshiro , Sakurai Katsutoshi
Published: October 2005

A piezoelectric vibratory gyrosensor, constructed using a trident tuning-fork resonator, is characterized by superior support construction. That is, for a trident tuning-fork, the vibrational loss with its support condition becomes so small that a gyrosensor has good performance compared with other existing type resonators. First, the vibration modes of a trident tuning-fork have been investigated, and suitable clamping conditions are clarified using finite-element analysis. Then, the method of adjusting the resonance frequencies between driving and detecting vibration modes and the influences of arm imbalance were studied. Moreover, when detecting the angular rates using a prototype trident tuning-fork resonator, the leakage output signal was apparently eliminated by connecting a differential circuit. As a result, a small-sized piezoelectric vibratory gyrosensor having good gyro-characteristics could be measured.
A measure of dissimilarity for comparison of dynamics, agogics, and pedaling in several piano performances
Authors: Taguti Tomoyasu , Ohgushi Kengo , Sueoka Tomoko
Published: October 2005

Expressive performance of music is realized with local and global variations in dynamics, timing, intonation, timbre, etc., where particular profiles of these ‘‘expressive elements’’ depend on the players’ performance practices based on their musical thoughts. This paper presents a method to study the correspondence between the physical nature and the subjective effect of expressive elements in piano performances. Let f(s) be a function in musical time, wheres represents the temporal profile of physical correlates with either dynamics, agogics, or pedaling in a piano performance, and let n be the number of these performances for the same music score. The dissimilarity dij between two performances i andj is defined as the root mean square of fi(s)−fj(s) over the prescribed time spanS of the concerned music passage. The discussion focuses on: (1) the construction of f(s) for each of the above-mentioned expressive elements, and (2) the mapping ofn performances in a geometrical space with the dissimilarity matrix D=[dij], which is then related to the rating data of subjective impression obtained from a suitably designed listening session. As an example, the maps of dynamics, agogics, and pedaling are given for 24 performances for Chopin’s Waltz No. 9 rendered by eight pianists with three kinds of intended musical expressions, and the rating data from a listening session are associated with the maps.
Communicating performer intent through musical performance. I. Mapping intent to perception
Authors: Kendall Roger A. , Carterette Edward C.
Published: October 2005

Although several recent studies have involved experimental approaches to aspects of musical performance, most have focused on ‘‘emotive’’ communication or analyses of timing profiles in isolation. In this work, several frames of reference are integrated: notational (musical style), performer-generated messages (performer-intent), generator class (different instrument types), the link to the listener and listener knowledge (musician and nonmusician), and, finally, the mappings among frames. In this talk, methodological issues in the study of expressive musical performances are discussed, focusing on convergent operational definitions of variables. It is demonstrated, by experimental results, how different listener operations explicate different aspects of expressive communication. A unique feature of this work is the use of different musical style categories (baroque, classical, romantic, and early 20th century) which initiate the chain of musical communication, providing different contexts for the performer–listener mapping.
Communicating performer intent through musical performance. II. Mapping performer intent through acoustical analyses
Authors: Carterette Edward C. , Kendall Roger A.
Published: October 2005

In this phase of this research, the acoustical signals generated in expressive performance by orchestral instruments are parsed. Most studies of musical expression and performance have concentrated on the profiles that arise from MIDI timing data. Here, the signals of ordinary orchestral instruments are employed from these studies of expressive communication, and analyses are provided that map timing, amplitude, and spectral measures to performer messages. Different instruments have different combinations of drivers, resonators, and couplings, and the resultant acoustical signal contains information about these. Recently, in the laboratory, Hajda has explored spectral centroid trajectories as a means of identifying attack characteristics, and this notion is applied to the issue of legato transitions in expressive musical performance. Timing and amplitude trajectory data from these experiments suggest that, while lesser musicians have a tendency to repeat similar gestures over the range of expression, highly trained performers at a virtuoso level are capable of distinct timing profiles under stylistically appropriate conditions which communicate their intent.
Acoustic correlates of the emotional expression in vocal performance
Authors: Ohgushi Kengo , Hattori Manami
Published: October 2005

Listening experiments and physical analyses of vocal performances were made to investigate how the emotional expressions were transmitted to listeners and to find acoustic correlates of each emotional expression. Three female singers were instructed to perform a short piece of music so as to communicate five basic emotions to listeners. The five basic emotions were ‘‘happiness,’’ ‘‘sadness,’’ ‘‘anger,’’ ‘‘fear,’’ and ‘‘without expression.’’ Some listening experiments revealed that, on the whole, the singer’s intention and the listener’s impression, although there were individual discrepancies, were in general agreement. The performances were analyzed regarding physical parameters such as tempo, dynamics, agogics, intonation, vibrato, and so on. The relationships between the expressive intention of the singers and measured physical parameters were revealed.
Rhythmic interpretation of polonaise in piano performances
Authors: Ohta Kimiko , Taguti Tomoyasu
Published: October 2005

A method for analysis of rhythmic interpretation of a characteristic rythmic pattern in polonaise is presented. The pattern concerned is one 8th note followed by two 16th notes. By physical measurement of timing for this pattern as it appeared in the first beat in several performances of Chopin’s polonaise (Grande Polonaise Op. 22), the duration of this pattern was generally found to be lengthened considerably. Further, a listening experiment showed that this portion had a rhythmic stress (of lengthening accent). To characterize the expressive timing of the pattern, a pair of ratios, P=[a,b] with a=x:1 and b=1:y, was introduced, where a denotes the ratio of durations of the 8th note to the sum of two 16th notes, and b the ratio of the two 16th notes. TheP ’s from the performances by six pianists were plotted in the x-y plane. The result revealed a clear distinction among individual rhythmic interpretations of the six pianists, e.g., x<1 and y≳1 for the P’s of three pianists, which implies that they put a stress on the second 16th note.
The touch precursor of the piano tone
Authors: Naganuma Daisuke , Nakamura Isao
Published: October 2005

Recently research has discovered that sound appears before the contact of the string with the hammer in the piano tone. This sound is called the ‘‘touch precursor’’ or ‘‘early noise’’ and is observed only in a staccato type of touch [A. Askenfelt, Proc. SMAC 93, 297–301 (1993); G. W. Koornhof and A. J. van der Walt, ibid. 93, 318–324 (1993)]. In this article, analysis of the touch precursor is reported for two cases. The first case analyzed was the piano tone at three different levels (mezzoforte, forte, and fortissimo) played by a mechanical actuator. The touch precursor was observed in each sound. The results show that the lower the touch level becomes, the longer the duration time of the touch precursor becomes. The frequency of the touch precursor is almost constant, but slightly lower in the low-frequency range. The amplitude of the touch precursor gradually increases from the onset until the beginning of the string vibration. The second case analyzed was the piano tone played by a pianist using two different staccato touches, who pressed down the key by a strained finger and a relaxed finger. The results show that the duration time of the touch precursor is slightly different.
Modal decomposition results for active control of energy density
Authors: Sommerfeldt Scott D. , Parkins John W. , Tichy Jiri
Published: October 2005

In recent years, an alternative sensing approach has been developed for active control, based on minimizing the acoustic energy density at the error sensor location(s). This new approach has been tested both numerically and experimentally, with the results indicating that one can often achieve improved global attenuation of the field by minimizing the acoustic energy density, rather than the sum of the squared pressures. Previous results from minimizing the energy density at the error sensors have concentrated on investigating the control that can be achieved by looking at the global energy in the field before and after control, and also by looking at the attenuation that can be achieved as a function of frequency. However, it has also been found that additional insight can be gained by examining the acoustic field in terms of the acoustic modes contributing to the acoustic field. This paper will present some of the modal decomposition results obtained for different active control approaches. These results provide insight into the control mechanisms and provide indications as to why one can often achieve improved global attenuation by minimizing the acoustic energy density rather than the squared pressure.
Three-dimensional sound field simulation using the boundary integral equation method
Authors: Katsumata Shinichi , Hamada Hareo
Published: October 2005

Computer simulation is a useful technique for developing the active control system (referred to as the ANC system). In this paper, the technique is introduced of sound field analysis for an ANC system based on the boundary integral equation method (BIEM). Since the BIEM accounts for wave motion characteristics precisely, the dynamic behavior of the control sound field can be considered, especially in the low-frequency band. The objective of the study is to investigate a transient sound field by applying the BIEM to practical problems. In order to introduce the BIEM technique to actual situations, including boundary problems with the existing acoustic materials, a database was developed on the normal acoustic admittance ratio of the materials. The ordinary feedforward model of the ANC system was used to control the noise field in the computer simulations. The results, in which the transient sound fields controlled by the ANC system are shown, will be very useful in understanding how to build up the control sound field.
A study of visualization of a sound field
Authors: Suzuki Takeshi , Hamada Hareo
Published: October 2005

The generated noise caused by the fluid inside a duct is difficult to estimate accurately due to the difference of power between fluid and noise caused by the fluid. However, it would be required to estimate the distribution of sound pressure inside the duct to introduce the active noise control techniques effectively. The objective of this paper is to estimate the radiated acoustical energy and to visualize the distribution of the sound pressure inside an air-conditioning duct using the acoustical power balance method. This method is suitable for analyzing complicated random noise at a fairly high frequency. Also introduced was a new method of the boundary integral equation to analyze the dynamic behavior of sound fields. The analysis of sound fields controlled by an active noise control system will be shown with the dynamic time-domain visualization of the sound-pressure field.
Active vibration isolation using vibrational power as a cost function
Authors: Howard Carl Q. , Hansen Colin H.
Published: October 2005

Active isolation of a vibrating rigid mass from a flexible simply supported beam is investigated theoretically and experimentally. Results obtained using vibrational power transmission as a cost function are compared with those obtained using base acceleration and transmitted force as cost functions. One problem with using vibratory power transmission as a cost function is the lack of correlation between the reference and error signals due to the frequency doubling effect of the multiplication operation used to obtain power. This problem is addressed by heterodyning the frequency doubled-error signal with the reference signal to obtain an error signal with the same frequency components as the reference signal, but with the amplitude dependent on the frequency doubled-error signal amplitude. Theoretical results indicate that it is possible to achieve zero vibratory power transmission into the beam irrespective of whether the cost function used is vibratory power, beam acceleration at the base of the isolator, or transmitted force. Experimental results show that similar isolation efficiencies are obtained for all three types of cost function with the achievable efficiency dependent upon the accuracy of the digital control system.
Ultrasonic study of the main (α) relaxation in an epoxy resin
Authors: Matsukawa Mami , Ohtori Norikazu
Published: October 2005

The isothermal polymerization process of a common epoxy system (prepolymer: diglycidyl ether of bisphenol A, curing agent: diamine) has been characterized in the MHz range by ultrasonic pulse spectroscopy. The longitudinal wave velocity increased during polymerization. The profile of longitudinal wave velocity and attenuation depended on the curing condition (temperature and mixing ratio of the curing agent). In addition, velocity and attenuation showed clear effects of the main (α) relaxation, which can be observed during glass transition of the resin. This polymerization process was also observed in the GHz range by Brillouin-scattering measurements. In this frequency range, the polymerization process was also observed as the increase of velocity. However, the velocity values were much higher than those observed in the MHz range from the beginning of polymerization. By considering the glass transition temperature of the prepolymer (about −20 °C) used, this velocity difference indicates the possibility that the main (α) relaxation of prepolymer used situated between MHz and GHz ranges. To confirm this idea, the temperature dependences of the velocities were observed. The velocity difference became smaller as the temperature increased, which showed a smaller effect of relaxation at higher temperatures.
A general energy conservation law in dielectrics
Authors: Nelson Donald F.
Published: October 2005

To study the interaction of acoustic waves with other excitations in a dielectric crystal it is necessary to have a consistent set of coupled dynamic equations for them. A particularly important consequence of those equations is the energy conservation law. A Lagrangian-based theory has been used to produce the most general energy conservation statement yet obtained in a dielectric. It includes acoustic waves, electromagnetic waves, spin waves, and optic modes of ionic, electronic, and excitonic origin. Further, the excitations can be arbitrarily nonlinear in any field or combination of fields, can interact with any multipole order of the bound charge density and its current density, can involve any derivative of a field, and can occur in crystals of any symmetry. It is applied to a soliton that is a mixed mode (a ‘‘polariton’’) of an acoustic wave and a ‘‘soft’’ optic mode at a temperature just above a ferroelastic phase transition. Such an interaction involves the acoustic coupling to the optic mode turning the quadratic potential energy of the latter negative and so needs a quartic energy to stabilize it. Allowed soliton velocities fill the gap of linear wave velocities produced by the polaritonic interaction. [Work supported by NSF.]
Acoustic cavity resonances as a probe of the interior surface geometry of nearly spherical closed shells
Authors: Asaki Thomas J. , Hoffer James K. , Sheliak John D.
Published: October 2005

Spherical shells are used for a variety of applications ranging from fundamental gas properties measurement in large resonators to studies involving millimeter-size prototype intertial-confinement-fusion (ICF) targets. Most applications demand that either or both shell surfaces have a high degree of sphericity. Fabrication from hemishells inevitably leads to geometric imperfections and leaves the interior surface unavailable to metrological inspection. However, many common asphericities are predicted to break the degeneracy of resonator modes to first order in a boundary perturbation expansion [J. B. Mehl, J. Acoust. Soc. Am. 79, 278–285 (1985)]. Various centimeter size aluminum and beryllium shells were manufactured with artificially enhanced common fabrication errors. The resonant modes of a completely closed shell are excited and detected using a swept-sine heterodyne technique [A. Miglioriet al., Physica B 183, 1–24 (1993)] with four pinducers in contact with the exterior at the tetrahedral angles. Both shell and interior gas resonances are distinguishable, are nearly uncoupled, and display measurable mode splitting. While various gases, pressures, and temperatures are examined, primary research involves materials and conditions relevant to the manufacture of ICF targets. Experimental results are compared with the perturbation theory, and the utility of the technique is examined.
An ultrasonic-electrostatic hybrid levitator for crystal growth from a solution
Authors: Chung Sang K. , Trinh Eugene H.
Published: October 2005

A novel approach to crystal growth from a solution has been introduced by combining the electrostatic levitation technology with the sample rotation capabilities of a single-axis ultrasonic levitator. In the current implementation, a 22-kHz standing wave is used to position and to rotate an electrostatically levitated 0.4-cm-diam droplet along a horizontal axis. Current studies are investigating the specific capabilities for rotation control (rotation rate and rotation axis orientation) as well as the trajectory of an immersed liquid and solid sample within the levitated solution droplet. The physical mechanism for torque generation is currently believed to be the aerodynamic drag from acoustic streaming flows external to the levitated droplet. The results of internal and external flow visualization studies are presented. [Work funded by NASA.]
Mechanical properties of a hyperswollen lyotropic smectic liquid crystals at low frequencies
Authors: Yamamoto Jun , Tanaka Hajime
Published: October 2005

Smectic liquid crystals are unique condensed phases in that they exhibit properties of a one-dimensional solid and of a two-dimensional liquid. There exist various types of the hydrodynamic modes, propagating and diffusive modes, such as second sound or layer undulation modes, related to the existence of the internal degree of freedom in the complex fluid. Mechanical properties have been investigated of hyperswollen lyotropic smectic phases, with focus on its low dimensionality and large intrinsic fluctuations. This layer structure is supported by the microscopic long-range intermembrane interactions such as electrostatic or steric repulsion that play an important role in the hyperswollen regime. The layer compressibility measurements tell one that the layer structure is supported by entropic repulsion, which originated in the undulation fluctuation motion of the membranes. The light scattering experiments are also shown which provide information on the relation between the static structure and the dynamics of hydrodynamic fluctuation modes.
Elastic properties of single- and multidomain crystals of LiTaO3
Authors: Takanaga Izumi , Kushibiki Jun-ichi
Published: October 2005

Ferroelectric single crystals of LiNbO3 and LiTaO3 are widely used as substrates for ultrasonic and optoelectronic devices. Obtaining homogeneity in elastic and optical properties of the crystals is one of the most important problems for wafer production. Recently, inhomogeneities of commercial wafers/crystals have been investigated with data of velocity changes obtained by line-focus-beam acoustic microscopy. The variations of the elastic properties are considered to be due primarily to chemical composition changes and secondarily to residual multidomains. In this paper, a fundamental study of the differences in elastic properties between single- and multidomain crystals of LiTaO3 is conducted by measuring the longitudinal velocities forX -, Y-, and Z-cut specimens and the shear velocities for Z-cut specimens. Two sets of X-, Y-, and Z-cut specimens are prepared: One is for normal (single-domain) specimens and the other is for perfectly depoled (multidomain) specimens. For the longitudinal wave propagation directions along the Y and Z axes, the velocities for the single-domain specimens, due to the piezoelectricity, are 91.57 m/s (1.59%) and 92.70 m/s (1.50%) greater than those for the multidomain specimens, respectively. On the other hand, for the X-axis longitudinal and Z-axis shear wave propagation directions, the piezoelectricity is uncoupled, but very interesting velocity changes are found in that the longitudinal and shear velocities for the single-domain specimens are 48.45 m/s (0.87%) and 135.59 m/s (3.79%) lesser than those for the multidomain specimens, respectively.
Eighth-nerve responses to sideband-attenuated and center frequency phase-shifted three-tone complexes
Authors: Chronopoulos Michael F.
Published: October 2005

In a previous study [M. Chronopoulos and R. R. Fay, J. Acoust. Soc. Am.99 , 2583–2584 (1996)], it was shown that goldfish (Carassius auratus) perception of three-tone complexes with either reduced modulation depths or a phase shift introduced at the center frequency (CF) is independent of both fine structure and power spectra of the signals. Behavioral responses were accounted for by a single function of the signals’ normalized fourth moment of the envelope (NFME). The current experiment investigated the neurophysiological correlate of the goldfish’s auditory nerve fiber’s (saccular fiber’s) responses to previously measured behavior. Signals included a 100% sinusiodally amplitude-modulated (SAM), a 350-Hz tone modulated at 30 Hz, and three-tone complexes with reduced modulation depths (MD). Reduced MD were achieved by either attenuating the sidebands (320 and 380 Hz) or phase shifting the CF component (350 Hz). Period histograms of single auditory fibers’ responses were calculated. The histograms showed phase locking of the neural response to the envelope of the stimulus. The NFME of the histograms were measured. The NFME of the response histograms declined as a function of increasing sideband attenuation and increasing phase shift. Similar to behavioral measurements, NFME declined as a single function of the NFME of signals. [Work supported by a NIDCD Program Project Grant.]
Neuronal correlates of pitch in the inferior colliculus
Authors: Depireux Didier A. , Shamma Shihab A.
Published: October 2005

Characteristics of single neuron responses underlying possible mechanisms for the extraction of the pitch of complex tones in the inferior colliculus (ICC) of anesthetized ferrets has been studied. Sounds such as amplitude-modulated tones, trains of clicks, and other spectrally complex sounds were used. It has been observed that the fine structure of a contralaterally presented stimulus can be found, perhaps even enhanced, in the firing patterns of collicular stellate cells. Ranges of latencies, best modulation frequencies, and center frequencies in the responses were found, as found before; more importantly perhaps, very short, stimulus-independent periodicities in the response patterns were found, as by Langner [G. Langner, Hear. Res. 60, 115–142 (1992)]. The functional significance of these findings, and in particular of these ‘‘intrinsic oscillations,’’ with respect to the problem of pitch extraction by the auditory pathway, will be discussed in the context of a model. [Work supported by ONR, NIDCD, and NSF.]
On the relationship between the autocorrelation function of continuous brain waves and the subjective preference of the sound field in change of the IACC
Authors: Nishio Kazuki , Ando Yoichi
Published: October 2005

This study analyzed the range of α waves (8–13 Hz) of continuous brain waves (CBW) and compared them with the scale value of the subjective preference of the sound field in a change of the interaural cross-correlation function (IACC) [Ando, Concert Hall Acoustics (Springer-Verlag, Heidelberg, 1985)]. The source signal was Sinfonietta, Opus 48; third movement, composed by Arnold. The scale value of the subjective preference and the CBWs to a paired stimuli, i.e., reference stimuli (IACC=1.0) and test stimuli (IACC=0.3 or 0.65), which were presented alternatively were compared. It is found that the value of the effective duration (τe) of the autocorrelation function (ACF) of the α waves from only the right hemisphere corresponds well to the subjective preference. It is considered, therefore, that τe is an objective measure reflecting the subjective preference [Chen and Ando (unpublished)].
Dynamic auditory representations and statistical speech recognition
Authors: Strope Brian , Alwan Abeer
Published: October 2005

The most common spectral estimation algorithm used for automatic speech recognition incorporates rough approximations of basic aspects of auditory modeling: frequency selectivity and magnitude compression. Attempting to improve the robustness and overall performance of ASR, researchers have proposed more sophisticated auditory models as the spectral estimation front end, with generally modest success at best. One common concern throughout these efforts is that the representation derived from an auditory model may not be a good match for typical statistical recognition algorithms. Recently, a dynamic auditory model that emphasizes changing local spectral peaks and has improved recognition robustness compared to other common front ends has been derived and implemented. The present work uses specific case examples to show how the perceptual representation leads to a softening of the resulting statistical models. The works also proposes a simple mechanism to adapt dynamic spectral features into a form more suitable for segmentally static statistical characterization. The mechanism is based on approximating the temporal derivative of the frequency position of local spectra peaks. The impact of our auditory model with this processing mechanism on robust recognition performance is discussed. [Work supported by NIH Grant No. 1 R29 DC 02033-01A1, and by NSF.]