bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasticity of spectrotemporal sensitivities in auditory cortex
Authors: Mercado Eduardo , Shohamy Daphna , Orduna Itzel , Gluck Mark A. , Merzenich Michael M.
Published: July 2002

Response characteristics of auditory cortex can be altered by repeatedly pairing sounds with basal forebrain stimulation [M. P. Kilgard and M. M. Merzenich, Science 279, 1714–1718 (1998)]. Although many neurons in auditory cortex respond most strongly to time-varying sounds, most studies of stimulation-induced plasticity have focused on changes in responses to tone pips. We examined stimulation-induced changes in neuronal sensitivities to frequency-modulated sweep trains (bandwidth=2–16 kHz, duration=1 s, sweep rates=4–24 octaves/s, repetition rates=2–24 sweeps/s). Adult rats received electrical stimulation of basal forebrain paired with 1–10 varieties of sweep trains, 300–500 times per day, for 9–16 days. Some sounds were presented in combination with bandlimited Gaussian noise. After stimulation, neuronal responses were recorded from 20–80 sites in the auditory cortex of each rat. The spectrotemporal sensitivities of auditory cortical neurons were dramatically altered in stimulated rats. Changes in response characteristics were not straightforwardly related to features of the sounds that had been paired with stimulation. Certain sounds that normally evoked responses correlated with sweep repetition rate in control rats tended to evoke either aperiodic or uncorrelated periodic responses from neurons of stimulated rats. Current theories of auditory cortical plasticity do not account for these results. [Work supported by MBRS, NIMH, NSF.]
Effect of shock waves on cytoskeleton of human renal cell carcinoma
Authors: Moosavi Nejad S. , Satoh Makota , Ioritani Naomasa , Orikasa Seiichi
Published: July 2002

The first clinical extracorporeal shock wave lithotripsy (ESWL) in early 1980 revolutionized the surgical management of urolithiasis. Since then, studies have been under way to discover additional uses of ESWL in other areas of medicine including treatment of cancer. However, the shock wave tissue interactions have not yet completely been understood. To analyze in vitro subsequent alteration of cell cytoskeleton, cultured human renal carcinoma cells were exposed to the underwater shock waves, generated by an experimental setup with 20 MPa overpressure at the focal region. The cultured cells provided a three-dimensional lattice work of structural proteins (actin, tubulin, and vimentin) analogous to those observed in the solid tumor. Scanning electron microscopic examination revealed morphological changes of the treated cells located in the focal region. Cells were detached from the substratum and changed from the normal fibroblast-like shape into a spherical shape. Disorganization and disassembly of the fibrillar cytoskeletal proteins were observed in the treated cells by immunofluorescence microscopy. The detached cells were collected and recultured again. After 6 h of spreading on a culture dish, reorganization of those fibers in the treated cells was compared with control cells and no significant difference was found.
Recent transmit-mode experimental results on thicker injection molded 1–3 piezocomposite
Authors: Benjamin Kim
Published: July 2002

Three transducers which utilize a new 25.4-mm (1.0-in.)-thick injection molded 1–3 piezocomposite as the active material have been fabricated and acoustically calibrated in the transmit mode. The study, which included a single, double, and quadruple layer assembly of 25.4-mm (1.0-in.)-thick composite, indicates that considerable transmit source levels are possible over a very broad frequency range using this newly developed thicker material. Furthermore, the element design can easily be packaged into various two-dimensional array configurations. For the multilayer cases, the nulls present in the untuned response were mitigated by applying appropriate phase shifts for each individual layer. Measured results compared well with model predictions for all three cases, indicating that the transducer layering scheme was properly implemented. [This work was funded by NAVSEA NUWC Code 82 and Code 21.]
An acoustic volumetric array system
Authors: Rigelsford Jonathan M. , Tennant Alan
Published: July 2002

A microphone array system based on a three-dimensional random geometry is introduced. Three-dimensional microwave volumetric array antennas have recently been investigated as potential systems for radar and communications applications [A. Tennant and A. F. Fray, ‘‘A 64 element broad band volumetric array antenna,’’ IEEE International Antenna and Propagation Symposium, Atlanta, 1998]. In a volumetric array, the elemental receivers occupy a solid region of three-dimensional space. A spherical array geometry is preferred. This provides the potential for full scan coverage. The projected aperture of a spherical array is direction independent, with the beam width and gain of the directional response being constant for all scan angles. The system developed consists of 64 omnidirectional microphones arranged at pseudorandom locations within a spherical volume. The nonperiodic element arrangement has two advantages. First, it eliminates the possibility of large grating lobes, and therefore enables wide-angle beam steering over a very large frequency bandwidth. Second, this geometry results in an array reception pattern with an average side-lobe level that is inversely proportional to the number of array elements. The potential of acoustic volumetric arrays is examined and the results of theoretical and experimental investigations presented. Applications areas include covert surveillance, imaging, and auditorium characterization.
Asking the right questions and following through: Obstacles encountered by prospective authors
Authors: Pierce Allan D.
Published: July 2002

Much of the best work in acoustics is presented at the Society’s meetings. The Journal benefits if more presenters of such work submit archival-quality manuscripts. Obstacles include writer’s block, counter-pressures from employers and others, inadequate support services, poor time organization, distrust (not necessarily unjustified) of the fairness and value of the JASA peer reviewing process, and a lack of appreciation of the long-term value of JASA publication. The Editor advocates expending the effort, gives suggestions on how authors can overcome the obstacles, and presents ideas (and pleas for suggestions from authors) as to how manuscript processing can be improved. The continued increase in quality of those papers eventually published remains the Journal’s foremost priority, and authors can help by giving more attention to the selection of questions addressed in their research and by justifying the significance of such questions in their manuscripts. Recognition of the ‘‘right question’’ is an art that can be acquired, but which requires continued effort. Stimulation comes from many sources; the Editor especially recommends extensive reading of current literature, careful listening to talks at the ‘‘right’’ meetings, and a rapport with researchers who have a knack for asking the ‘‘right questions.’’
Publishing speech papers in JASA
Authors: Lofqvist Anders
Published: July 2002

There are three sections for speech communication papers in JASA: production, perception, and processing and communication systems. In contrast to some other branches of acoustics, authors of speech-related papers have a wide variety of journals to choose from, covering several different disciplines. Among these are journals in psychology, cognitive science, linguistics, phonetics, speech and hearing science, otorhinolaryngology, neurophysiology, human movement science, and signal processing. Speech papers also cover production and perception in different human languages. In addition, papers in speech deal with both normal and clinical aspects, e.g., voice and speech disorders, and the effects of hearing impairment on speech. Papers in speech production are also concerned with analyzing articulatory movements as well as the mathematical modeling of phonation and articulation. The presentation will focus on why JASA should be a top choice for authors of papers in speech communication. Criteria for the selection of speech papers will be discussed as well as reviewing policy.
Holographic analysis of musical instruments
Authors: Rossing Thomas D.
Published: July 2002

Musical instruments, when excited by bowing, plucking, blowing, or striking, vibrate in rather complicated ways. These complicated vibrations can be described in terms of normal modes of vibration, and understanding the normal modes or eigenmodes is important to understanding sound production in the instrument. Holographic interferometry offers by far the best spatial resolution of operating deflection shapes (and hence of normal modes), since it looks at an almost infinite number of points. Holographic interferograms may be recorded on photographic film or electronically by means of TV holography. We discuss various methods for holographic interferometry and its applications to several different types of musical instruments.
A real-time/non-real-time spectrum analyzer for musical sounds
Authors: Beauchamp James W. , Madden Timothy J.
Published: July 2002

A color spectrum analyzer specialized for visualization of musical sounds has been developed for the Macintosh Power PC computer. Input samples (monaural or stereo) can be obtained from microphone or CD-ROM input in real time or from a sound file in nonreal time. Spectral analysis can be tuned specifically to the fundamental frequency of the input signal using sample rate conversion (tuned case), or it can be based on a specified window size at the input sample rate (nontuned case). In the tuned case each spectral component corresponds to a harmonic of the input. Several different displays can occur simultaneously: an oscilloscope waveform display; a 1D spectrum, where an amplitude-vs-frequency graph varies as time progresses; a spectral waterfall display; a 2D spectrum showing frequency vs time with amplitude registered as degree of display brightness; a 3D display showing amplitude vs time vs frequency at an arbitrary orientation. In addition to time-varying graphs which are available for both real and nonreal time, static plots are available for preanalyzed file input. For stereo signals it is possible to plot output/input transfer functions. Spectral time averaging is also available for cases where the instantaneous spectrum is unstable
The Nakoryakov–Pokusaev contribution to the acoustics of multiphase flow
Authors: Schreiber Isaac
Published: July 2002

Under the guidance of academician Nakoryakov and Professor Pokusaev, a cycle of theoretical and experimental studies of wave propagation in the gas–vapor bubbly liquid has been accomplished. It established the basis for the gas dynamics of gas–liquid multiphase flow. Here the main achievements will be listed. (1) The bridge was built between the modern theory of nonlinear waves and the progress in heat transfer. (2) The comprehensive picture of the dynamics and structure of the wave propagation in gas–vapor bubbly liquid was found. The main bright results are the following: discovery of oscillating and monotonic shock waves and derivation of criteria for their existence; models for sound propagation in bubbly liquid and in boiling water (Korteveg–Burgers and Klein–Gordon approximations); acoustics of the slug-plug regime; two-wave structure of shock waves with shape fronts. These results strongly influenced the modern theory of the acoustics of foams and solids saturated by bubbly liquid. This lecture is dedicated to the jubilees of Nakoryakov (65th birthday) and Pokusaev (65th birthday).
A comparative study of the scattering cross sections from incident plane wave acoustic waves on submerged evacuated and water-filled elastic shells
Authors: Uberall Herbert , Werby Michael F.
Published: July 2002

Employing the acoustic background for the case of elastic solids and elastic shells has facilitated the study of elastic resonances excited by incident acoustic signals. Once an adequate acoustic background became available it became possible to properly isolate and characterize such resonances. The recent development of an acoustic background for water-filled elastic shells allows for the characterization of water-filled shells. We present a comparative study for the elastic shell case for the evacuated and water-filled cases and thereby seek to elucidate new resonance mechanisms for the fluid-filled case.
New techniques for the characterization of materials in situ using ultrasound
Authors: Christidis Konstantinos , Gunarathne G. P. P.
Published: July 2002

Characterization of materials in situ using ultrasound is an attractive concept but has two main problems due to: (1) arbitrary geometrical shape of the target, and (2) surface roughness of the material. Some work has been previously reported in measuring the surface roughness using ultrasound [J. Stor-Pellinen and M. Luukkala, Sensors and Actuators A49, 37–40 (1995)] and also material characterization using ultrasonic feature extraction [G. P. P. Gunarathne and R. W. Keach, Ultrasonics 34, 411–419 (1996)]. However, there is no integrated approach developed to characterize materials in situ, taking into account the effects due to shape and roughness of the target. In this work a comprehensive study of the effects of target shape and roughness on ultrasonic time- and frequency-domain measurements were carried out. A mathematical model which compensates for these variables was then developed, so that the compensated signals could be used to evaluate the material properties. Using these mathematical models and practical measurements, a formula which compensates for the combined effect of curvature and target roughness was developed. This model was then used to characterize materials in situ, using stored data and artificial neural networks. Close agreement between theoretical and practical measurements has been demonstrated.
Spatial unmasking of nearby pure-tone sources in a simulated anechoic environment
Authors: Kopčo Norbert , Shinn-Cunningham Barbara G.
Published: July 2002

Spatial unmasking of nearby pure-tone sources masked by broadband noise was studied in a simulated anechoic environment. The predicted amount of binaural unmasking was calculated using interaural differences from a spherical-head model [B. G. Shinn-Cunningham, S. G. Santarelli, and N. Kopčo, J. Acoust. Soc. Am. (in press)] and the Colburn model of binaural processing [H. S. Colburn, J. Acoust. Soc. Am. 61, 525–533 (1977)]. Predictions were generated for several spatial configurations of signal and masker in the horizontal plane (varying target and masker azimuthal positions and distances) and for multiple tone frequencies. Predictions were compared with behaviorally measured detection thresholds obtained with headphone simulations using individually measured HRTFs. Results show that changes in detection threshold for free-field signals are dominated by monaural effects due to large interaural level differences. Overall, spatial unmasking effects are very large for nearby sources due to simple energy effects at the better ear. Binaural unmasking is observable only for a subset of spatial configurations where the energy of signal and/or noise at both ears is sufficient to allow binaural processing, and even for these configurations the effect is generally weaker than that observed with distant sources. [Work supported in part by AFOSR Grant F49620-98-1-0108.]
Electro-elastic laminate theory for discrete piezoelectric patches on laminated plates
Authors: Gopinathan Senthil , Varadan Vasundara , Varadan Vijay
Published: July 2002

Classical laminated plate theory (CLT) has been applied successfully in the past to laminates with discrete piezoelectric patches bonded to the surface or embedded within the layers (1–7). The basic assumptions made in the earlier models were that the strains inside the patches are assumed to be constant and hence the presence of the sensor and actuator patches were neglected while modeling the dynamic properties of the laminate. The validity of these assumptions, the effect of the size of the patches and these assumptions on the solutions obtained, has not been studied. In this paper, the CLT is applied to a laminate with surface-bonded piezoelectric patches without the above-mentioned assumptions. A detailed modeling of the patches is developed by expressing the electric potential inside the patch as a quadratic function of thickness coordinate. The equations of motion are derived for a generally orthotropic laminate and solution method for these equations. Analytical solutions are obtained for a plate bonded with one and five collocated piezoelectric actuator/sensor patches. The effect of the passive and active stiffness of the surface bonded actuator and sensor patches on the dynamic characteristics of host plate structure is studied.
Impact of piezoceramic transducer hysteresis in the hybrid structural vibration control problem
Authors: Lee Soon-Hong , Royston Thomas J.
Published: July 2002

Hybrid vibration control via passive electrical shunting and active actuation of a piezoceramic wafer bonded onto the surface of a simply supported beam is investigated theoretically and experimentally with emphasis on modeling and understanding the impact of the piezoceramic hysteresis. A nonlinear rate-independent hysteresis model is experimentally identified for the PZT wafer by itself and then integrated into the coupled dynamic equations of the overall system consisting of the beam and electrically shunted PZT wafer. Experimental studies of the system validate the theoretical model. This model is then used to investigate the impact of PZT hysteresis on its vibration control performance in passive, active, and hybrid scenarios. [Work supported by grants from ONR and NSF.]
Active vibration isolation using variable structure control strategy
Authors: Pan Jiaqiang , Pan Shuwen
Published: July 2002

In this paper, the authors present a new type of control design methodology used for active vibration isolation: Variable Structure Control (VSC) with sliding mode. VSC is a special control strategy that is capable of making a control system very robust with respect to system parameter variations and external disturbances, and providing an easy way to design the control law for a plant, linear or nonlinear. It has developed into a general control design method and been applied to a wide variety of engineering systems since the 1990s. In this study, a vibration isolation system with both active and passive isolators is designed based on Ackermann’s method. Using this method, designed control law can make system states move in a time-variant sliding mode surface in state space from initial moment. This ensures the stability and robustness of the closed-loop system. Designed feedback control law can be expressed explicitly by state variables and parameters of the nominal system without any uncertainty and is easily applied in practice. Simulation results of an active suspension of vehicles show that the control system using VSC strategy possesses good performance.
Comparative perception of voicing contrasts
Authors: Sinnott Joan M. , McArdle Laura A.
Published: July 2002

English, Spanish, and monkey listeners were compared in their perception of a synthetic labial VOT continuum (−60 to +70 ms). A go-right/go-left ID procedure was used, with food reinforcement for monkeys. In exp. 1, subjects first learned to identify the endpoints of the continuum as ‘‘BA’’ or ‘‘PA,’’ and then generalization responses were obtained for intermediate stimuli. The mean boundary for English listeners was at +25 ms, while boundaries for Spanish listeners ranged from −15 to +25 ms (mean=7.6 ms). The monkey boundary was near 0 ms and appeared to simply bisect the continuum, suggesting that the English boundary at +25 ms is not a salient feature of the ‘‘general auditory system’’ in the context of prevoiced stimuli. In exp. 2, subjects were trained to differentiate VOT contrasts that crossed either the ‘‘English’’ or the ‘‘Spanish’’ boundary. While subjects learned to reliably differentiate both contrasts, reaction times were fastest for the English contrast. These results indicate that although attentional differences between subject groups may influence their generalization responses along a VOT continuum (exp. 1), these groups have similar sensory capacities when explicitly trained to differentiate specific stimuli along a VOT continuum (exp. 2). [Work supported by NIDCD.]
Coproduction in VCV disyllables produced by children and adults
Authors: Gelfer Carole E. , Bell-Berti Fredericka
Published: July 2002

Previous studies of speech production of young children have suggested differences from adult productions. For example, developmental differences have been noted for VOT and the extent of coarticulation between vowels and fricatives. This study explores developmental trends for consonant-vowel interactions in VCVs disyllables as evidenced by spectral differences in V1 as a function of C and V2 identity, where V1 is schwa, C is one of the following: /p, t, k, b, d, g, s, sp, st, sk/, and V2 is /i/ or /u/. The children in this study are between the ages of 4 and 6. Measures of F2 at both the offset and midpoint of schwa will be used to determine (1) the extent to which interactions show developmental trends, and (2) whether the extent of these interactions for either or both groups of speakers is influenced by consonant manner of articulation, place of articulation, and/or duration.
A comparison of the vowel sequence illusion and the verbal transformation effect
Authors: Cooley Jeffrey M. , Warren Richard M. , Bashford James A.
Published: July 2002

When repeated sequences of steady-state vowels have durations of their phonetic components below the 100-ms threshold for identification of order, the phonemes lose their identity. The sequences are heard as syllables occurring in the listener’s lexicon (the Vowel-Sequence Illusion). When listening to repeating words, listeners also hear illusory syllables occurring in their lexicon (the Verbal-Transformation Illusion). Verbal transformations require the decay (satiation) of the initial veridical organization before the repetition-induced shifts in criteria permit nonveridical forms to be heard: The Vowel-Sequence Illusion does not require initial verbal satiation, and hence permits repetition-induced criteria shifts to tap directly into the lexicon-based syllabary. The intrinsic differences in the nature of the phonetic stimuli producing the two illusions result in characteristic distinctions between the organizations heard in the two illusions. Among these distinctions is the spectral splitting of the vowel sequences into two simultaneous organizations, one consisting of components above and the other below the 1500-Hz crossover frequency encountered in other contexts. This and other aspects of the two verbal illusions will be compared and contrasted, and demonstrations of both will be available. [Work supported by NIH.]
Matched-field processing in shallow water in the presence of soliton packets
Authors: Stamoulis Catherine , Orr Marshall , Dyer Ira
Published: July 2002

The performance of matched-field processing algorithms in shallow water, in the presence of soliton packets, has been investigated through analysis of data from the SWARM 95 experiment. In particular, acoustic data collected with a vertical array and a moving up-sweep source have been analyzed, in the frequency range 275–350 Hz. The source was placed below the surface mixed layer and its distance from the array varied between 2.5 and 27 km. Source localization using the conventional and minimum variance matched-field algorithms has been performed, in order to assess the robustness of these processors in the presence of environmental mismatch and their degradation as a function of range. The primary result of the analysis is that both processors fail to localize the source accurately, even at the shortest range (2.5 km). Although broadband processing and inclusion of corrections for the array tilt improved the results, the errors in source range (of the order of 1 km at short ranges and 5 to 10 km at long ranges) and depth remain significant. The performance of other matched-field processors is currently investigated.
Relating modem performance to the ocean channel properties
Authors: Porter Michael , McDonald Vincent , Rice Joseph , Baxley Paul
Published: July 2002

The ocean channel plays an important role in the performance of acoustic modems. However, the precise effects of such features as the sea surface, ocean bottom, bubble clouds, and internal waves is not well understood. In many shallow water areas the sound-speed profile varies from upward to downward refracting with the change of seasons enhancing the role of one or the other boundary. Furthermore, incoherent and coherent signaling schemes may be sensitive to different features of the propagation physics. To carefully study these issues, a series of experiments has been planned in diverse sites. The pilot experiment, ModemEx99, was conducted last May near San Diego and has revealed numerous interesting features. In particular, we see that there are strong transitions in the multipath structure with pronounced focal regions and shadow zones. These features correlate closely with areas of good and poor modem performance, respectively. This talk will interpret these results in light of the measured channel impulse response and predictions from broadband channel simulators.
Coherent underwater digital communication during LWAD 99-1 experiment: Performance and analysis
Authors: Al-Kurd Azmi
Published: July 2002

Underwater acoustic communications data using phase-modulated signals were collected during the Littoral Warfare Advanced Development (LWAD 99-1) experiment. The signals were projected from a drifting and a towed source. Data of several band rates were transmitted and used to study the temporal and spatial variation of the acoustic impulse response of the ocean and to evaluate the performance of a phase coherent digital communication algorithm. Postexperimental analysis showed that the experiment site is a harsh environment for coherent digital communication. The oceanic channel impulse response is very complex and represents a dynamic and extended multipath structure (changes in seconds). Also, the first arrival is weaker than the later arrivals (most of the time). In addition to the environmental limitations the receiver has to overcome system limitations and operate in a low signal-to-noise ratio conditions. Spatial and temporal diversity are implemented to improve the algorithm performance. The objective is to determine the characteristics of signal propagation in littoral environment, and to determine whether and how these characteristics affect the bit-error-rate. The results from this experiment and future experiments will serve as guidance in the design of a reliable coherent digital communication system.
Eliminating acoustical barriers to learning in classrooms—Case study of window ventilator noise
Authors: Brooks Bennett M.
Published: July 2002

Room ventilation systems have long been a major cause of noise in classrooms. The recent drive for energy efficiency has motivated schools to partner with utility companies to replace aging central HVAC systems with individual room heat pump window ventilator units for space heating and cooling. An unfortunate consequence is that these window ventilators are significant noise sources. A typical window unit can produce 70 dB(A), or more, at 1 m. Clearly, this is unacceptable. Either ventilator manufacturers must commit to reduce unit noise output by at least 30 dB, or school designers must abandon the wall ventilator option in favor of quiet central HVAC installations.
The acoustic characteristics of Korean traditional singing
Authors: Moon Seung-Jae
Published: July 2002

Korean traditional singing voice, called ‘‘Pansori,’’ is known for its peculiar sound quality compared to Western singing voice. It sounds very strained, yet hoarse. This study aims at investigating the acoustic characteristics of this singing voice. Singing voices of both male and female professional Pansori singers were recorded and analyzed. Also, regular conversation of one of the singers was recorded and analyzed to compare the singing vs conversational voice. From long-term average spectra of suspended vowels and from harmonic structure analysis, several things were noted. Pansori singing voice showed more gradual downslopes in spectrum envelope than normal voice. And conventional methods of measuring formant frequencies were of no use for this particular singing voice. Instead of showing regular vowel formant patterns, Pansori seemed to be characterized with irregular formant patterns such as a single prominent peak throughout the whole frequency range, especially in a strained voice. Conversation data revealed similar characteristics of the singing voice, indicating that these characteristics were the results of the permanent change of the singer’s vocal source, not the results of the mode switch. [Work supported by a Research Fund provided by the Korea Research Foundation, Support for Faculty Research Abroad.]
The effects of interfacial viscosity on the attenuation and phase speed of acoustic waves in bubbly liquids
Authors: Jankovsky Joseph C. , Roy Ronald A. , Carey William M.
Published: July 2002

The attenuation and phase speed of bubbly fluids have been shown to be highly dispersive due in part to the resonance response of individual bubbles. Surface-active materials, or surfactants, are known to dramatically alter the viscoelastic dynamics of an interface without affecting the bulk fluid properties. In this theoretical model the effects of surface viscosity on the propagation of linear pressure waves through a bubbly fluid are examined. The attenuation and phase speed are calculated for varying radii, void fraction, and interfacial viscosity for air bubbles in water. The results show an increase in attenuation for frequencies far removed from the bubble resonance for radii less than 100 microns. There is no significant increase in attenuation for larger bubbles (order 1 mm). Interestingly, near resonance, the interfacial viscous case has a lower attenuation than the clean interface, most likely due to the reduced radiation damping associated with smaller radial excursions. Likewise, resonance effects on the phase speed dispersion curve are also significantly diminished due to the interfacial viscosity. These results could be important for understanding propagation near the surface of the ocean, where surface-active materials can dramatically affect the dynamics of micron-sized bubbles and bubble distributions. [Work supported by ONR.]
Analysis of internal wave interactions with broadband acoustic signals propagating along the shelf during the SWARM’95 experiment
Authors: Mu Yongke , Badiey Mohsen , Siegmann William L. , Frank Scott , Lynch James F. , Wolf Stephen N.
Published: July 2002

A multi-institution experiment was conducted in 1995 on the New Jersey continental shelf to assess the Shallow Water Acoustic propagation in Random Media (SWARM’95). Two major source/receiver geometries were established. One was parallel to the continental shelf edge and the other was perpendicular. The orthogonal propagation consisted of two broadband sources transmitting signals perpendicular to the direction of internal wave field. The first signal was a transient airgun source (0.1-s duration), while the second was a linear frequency modulated sweep (30-s duration). Placed above and below the thermocline, these sources were transmitting signals every minute for a few hours at one location. Here we present a 2-h segment of these observations during 4 August 1995 when nonlinear internal waves were present. The transmissions were received by two vertical line arrays at different ranges and angles from the source. The dependence on the azimuth between the internal waves and the acoustic transmissions was examined. It is found that sound speed fluctuations induced by internal waves cause a 10–12-min temporal variations in the intensity of received signals. These temporal variations are azimuthally dependent since the environment is anisotropic due to internal solitary waves. [Work supported by ONR.]
Efficiency of barriers for transport noise insulation in the near-field region
Authors: Rybak S. A. , Kostarev S. A.
Published: July 2002

The efficiency of noise-insulating barriers needs to be carefully calculated in the near-field region where the Fresnel’s parameter is not valid. The correct calculative method for the diffraction across the barrier is developed, taking into account both the resonance absorption at the boundary of the barrier and its thickness for the low-frequency range. The comparison of the calculus and experiments for the barriers arranged along the transport lines was made and the agreement is sufficiently good.
The flowering of architectural acoustics in the twentieth century
Authors: Wetherill Ewart A.
Published: July 2002

Arising from a single building deficiency, the art and science of architectural acoustics came into being as a practical discipline at the start of the twentieth century through the painstaking exploration and profound intuition of Wallace Clement Sabine and other pioneers in acoustics. It now faces the dawning of the twenty-first century as a universal scientific discipline and an integral component of advanced building design. For the past 70 years of its often-fragile coexistence with the building professions, of architecture, much of the growth of understanding and education in architectural acoustics has found a focus in the Acoustical Society of America in collaboration with its companion societies throughout the world. While the understanding of building design for good hearing is still uneven and far from complete, the story of this development, as seen in the history of the Acoustical Society, indicates rich promise for the years ahead.
Scattering of sonic booms by anisotropic turbulence in the atmosphere
Authors: Kelly Mark , Raspet Richard , Bass Henry E.
Published: July 2002

An earlier paper [J. Acoust. Soc. Am. 98, 3412–3417 (1995)] reported on the comparison of rise times and overpressures of sonic booms calculated with a scattering center model of turbulence to measurements of sonic boom propagation through a well-characterized turbulent layer under moderately turbulent conditions. This detailed simulation used spherically symmetric scatterers to calculate the percentage of occurrence histograms of received overpressures and rise times. In this paper the calculation is extended to include distorted ellipsoidal turbules as scatterers and more accurately incorporates the meteorological data into a determination of the number of scatterers per unit volume. The scattering center calculation overpredicts the shifts in rise times for weak turbulence, and still underpredicts the shift under more turbulent conditions. This indicates that a single-scatter center-based model cannot completely describe sonic boom propagation through atmospheric turbulence.
Near-field–far-field measurement of loudspeaker response
Authors: Butler John L. , Sherman Charles H.
Published: July 2002

An improved method of determining the low-frequency far-field response of a loudspeaker, or other transducer, from near-field measurements is presented. The method is based on modeling the transducer as a thin disk vibrating uniformly on one side.
Scattering-induced attenuation of an ultrasonic beam in austenitic steel
Authors: Seldis Thomas , Pecorari Claudio
Published: July 2002

The scattering-induced attenuation coefficient of a beam of longitudinal waves propagating through an austenitic steel plate is measured as a function of the texture angle. The experimental data were obtained by mapping the incident and the transmitted ultrasonic field, and by evaluating the energy loss experienced by each plane wave component of the beam. Contrary to the behavior of data obtained by means of conventional techniques, that of the data reported in this work agrees qualitatively with the theoretical predictions. The reasons for the disagreement between theory and data obtained by means of conventional techniques are also discussed.
About a double-body immersion horn system to be used for quantitative sonochemical studies
Authors: Reisse J. , Bartik K. , Fabre O. , Vandercammen J.
Published: July 2002

The majority of quantitative sonochemical studies in the 20–100-kHz frequency range are performed by using an immersion horn system. The new system described in this letter consists of a double immersion horn acted on by a single pair of piezoelectric ceramics. This instrument is well adapted to the quantitative measure of effects, i.e., variations in the rate constant of a specific reaction associated to the change of an experimental parameter. The gas effect, obtained by comparing the rate of a reaction under air and under argon, illustrates the efficiency of the system.
The Recursive Theory of Slow Viscoelastic Flow Applied to Three Basic Problems of Hydrodynamics
Authors: Langlois W. E.
Published: July 2002

The flow-field and stresses, correct to the third order, are calculated for three basic problems of viscoelastic flow: the Poiseuille problem; helical flow in an annulus, and torsional flow between discs. The slow flow equations are set out in general tensor notation, then specialized to cylindrical polar coordinates and to spherical polar coordinates.
Viscoelastic Properties of Glucose Glass near Its Transition Temperature
Authors: Meyer H. H. , Ferry John D.
Published: July 2002

Storage (G′) and loss (G″) shear moduli of supercooled glucose have been measured at thirteen temperatures from 27.4 to 41.1°C in the frequency range from 0.3 to 1.8 cps. Shear creep has been measured at four temperatures from 41.1 to 47.6°C. The temperature dependence of the storage moduli and the creep compliance was described by reducing the time and frequency scales with shift factors calculated from the WLF equation, the constants corresponding to a fractional free volume of 0.026 at 41.1°C and a free volume expansion coefficient of 3.6×10−4 deg−1. The loss moduli plotted against reduced frequency did not give a single composite curve, however. Conversion of the dynamic measurements to creep compliance by approximation methods provided the latter function over ten decades of logarithmic time except for a gap of three decades in the middle of the range. At long times, the creep was indistinguishable from viscous flow; the viscosity at 41.1°C was 1.82×1010 poise. At short times, the limiting creep compliance appeared to be 0.32×10−16 cm2/dyne, and there was an additional time-dependent compliance of at least this magnitude with a broad distribution of retardation times. The relaxation and retardation spectra were calculated for this region.
Extrusion Rheology of Lubricated Polytetrafluoroethylene
Authors: Nakajima Nobuyuki , Stark Casper F. , Kim Young J.
Published: July 2002

Polytetrafluoroethylene is probably the only polymer which is commercially extruded in solid state. The polymer is provided in powder form which is lubricated by an oil. The samples of this study were powder of about 500 μ size, coagulated from latex particles of average .2–.4 μ. Naphtha was used as the lubricant at 16.5 weight percent of the composition. The pressure-output rate relation was examined with two types of capillary rheometers. A constant pressure rheometer was used to characterize the pressure range of 1000 3000 psi. The output rate at a given pressure decreased with time. A constant drive speed rheometer was used in the pressure range of 4000–14,000 psi. The recording of the force was very irregular but had an oscillating pattern. With both rheometers the extrudate diameters were equal or smaller than the die diameter. The compression experiment showed that the material behavior was dependent on not only the available free volume but the nature of powder itself. The compressive stress relaxation, however, depended on the free volume only. Recovery from compression was almost perfect.
Flow of colloidal aqueous silica dispersions
Authors: Persello J. , Magnin A. , Chang J. , Piau J. M. , Cabane B.
Published: July 2002

Concentrated dispersions of colloidal silica particles in water behave as soft solids. Under low stresses they show viscoelastic behavior, i.e., elastic response at short times and viscous creep at long times. Visualization of the deformation field shows that in this case the shear is homogeneous throughout the sample. Under large stresses they yield and accommodate any rate of shear; the dynamic yield stress follows the osmotic pressure of the dispersion. Visualization of the flow field shows that in this case the shear localizes in internal slip layers. The mechanism for localization results from release of water into fractures which let the solid regions flow past each other. At rest the solid regions reabsorb this water and heal the fractures. In this sense the flow is self-lubricating.
Rheological behavior of poly(methyl methacrylate) dispersions stabilized by a diblock copolymer: An anomalous viscosity–particle concentration dependence
Authors: Pavlı́nek Vladimı́r , Sáha Petr , Stejskal Jaroslav , Quadrat Otakar
Published: July 2002

The rheological study of dispersions of poly(methyl methacrylate) particles stabilized in decane by a steric stabilizer, polystyrene-block-poly(ethylene-co-propylene) diblock copolymer, revealed an extremely high apparent viscosity at low shear rates or even the yield stress at a relatively low volume fraction of particles (∼0.1). This behavior is due to highly interacting stabilizer macromolecules anchored to the particle surface. As the concentration of poly(methyl methacrylate) is further increased, the volume fraction of particles also increases, the particle diameter grows, the number of particles is reduced and the viscosity of the dispersion falls.
Sudden Conjunctivitis, Lymphopenia, and Rash Combined With Hemodynamic Changes (SCoRCH) After Trimethoprim-Sulfamethoxazole Use
Authors: O’Brian Madeleine , Rose Elysha K. , Mauskar Melissa M. , Dominguez Arturo R.
Published: November 2022

Importance

Trimethoprim-sulfamethoxazole (TMP-SMX) hypersensitivity reaction, ranging from circulatory shock to aseptic meningitis and respiratory failure, is a potentially life-threatening condition with dermatologic relevance.

Objective

To describe the mucocutaneous findings and clinical features of TMP-SMX hypersensitivity reaction.

Design, Setting, and Participants

This was a retrospective case series study of 7 patients who developed a characteristic rash, hemodynamic changes, and end-organ dysfunction after treatment with TMP-SMX at a large university hospital system during January 2013 to March 2022.

Exposures

Treatment with TMP-SMX within 2 weeks of the reaction.

Main Outcome and Measures

Descriptions of the condition, including the demographic information of the affected population, the reaction timeline, and mucocutaneous and clinical features.

Results

The cohort comprised 7 patients (median [range] age, 20 [15-66] years; 4 female and 3 male). The most common mucocutaneous findings were generalized sunburn-like erythema without scale, conjunctivitis, and mild facial and acral edema. Three patients had previous exposure to TMP-SMX and developed symptoms in 1 day or less, while those without prior exposure presented from 4 to 11 days after drug initiation. Among the 7 patients, 6 had fever, 7 had hypotension, and 7 had tachycardia. All patients had lymphopenia and evidence of end-organ dysfunction with either kidney or liver involvement. Median (range) time to resolution was 72 (48-96) hours.

Conclusions and Relevance

This retrospective case series indicates that SCoRCH (sudden conjunctivitis, lymphopenia, and rash combined with hemodynamic changes) should be considered in the differential diagnosis of patients presenting with acute generalized sunburn-like erythema, conjunctivitis, systemic symptoms, and hemodynamic changes in the setting of recent TMP-SMX use.
Racial and Ethnic Disparities in Buprenorphine Treatment Duration in the US
Authors: Dong Huiru , Stringfellow Erin J. , Russell W. Alton , Jalali Mohammad S.
Published: November 2022

This cohort study examines racial and ethnic differences in the duration of buprenorphine treatment for opioid use disorder in the US from 2006 to 2020.
Association of visual display terminal time with prevalence of temporomandibular disorder among Japanese workers
Authors: Zaitsu Takashi , Inoue Yuko , Oshiro Akiko , Nishiyama Akira , Kawaguchi Yoko , Aida Jun
Published: November 2022

Objectives

Visual display terminal (VDT) time has been reported to affect the development of temporomandibular disorders (TMDs). However, no study has investigated the association between VDT time at and outside of work with TMDs Adjusting for known TMJ risk factors. This study aimed to investigate whether TMDs were associated with VDT time at and outside of work after adjusting for various working conditions in Japanese workers.

Methods

This cross-sectional study was based on an internet survey of 3930 workers (2057 men and 1873 women), The TMD Screening Questionnaire (SQ-TMD), occupational factors, VDT time at and outside of work, psychosocial factors, and habits were assessed. We applied logistic regression to estimate the odds ratio (OR) of VDT time on SQ-TMD with adjustment for confounders.

Results

The mean age of the respondents was 43.3 ± 11.7 years, and 778 (19.8%) and 3152 (80.2%) subjects were at high and low TMD-related symptoms (TRS). Logistic regression analysis adjusting for all covariates (Model 2), the prevalence of high TRS was significantly higher among those with VDT time at work of 60–179 min (OR = 1.52, 95% CI 1.18–1.94), 180–359 min (OR = 1.27, 95% CI 1.00–1.62), and more than 360 min (OR = 1.44, 95% CI 1.10–1.88) compared to those with 0–59 min. However, there was no significant difference in the prevalence of high TRS for VDT time outside of work.

Conclusion

VDT time at work, but not VDT time outside of work, influences the prevalence of TRS. Since the association between VDT time at work and the prevalence of TRS was found even after adjusting for sociopsychological factors and habits generally associated with TMD, further investigation of other factors is needed.
Liquid Core Nanoparticle with High Deformability Enables Efficient Penetration across Biological Barriers
Authors: Wang Chun , Xiao Jian , Hu Xinyue , Liu Qi , Zheng Yadan , Kang Ziyao , Guo Dongsheng , Shi Linqi , Liu Yang
Published: November 2022

Biological barriers significantly limit the delivery efficiency of drug delivery systems, resulting in undesired therapeutic effects. When designing a delivery system with optimized penetration behavior across the biological barriers, mechanical properties, such as deformability, are emerging as important parameters that need to be considered, although they are usually neglected in current research. Herein, a liquid core nanoparticle (LCN) composed of a polymer‐encapsulated edible oil droplet is demonstrated. Owing to the unique structure in which the liquid oil core is encapsulated by a layer of highly hydrophilic and cross‐linked polymer, the LCN exhibits high mechanical softness, making it deformable under external forces. With high deformability, LCNs can effectively penetrate through several important biological barriers including deep tumor tissue, blood–brain barriers, mucus layers, and bacterial biofilms. Moreover, the potential of the LCN as a drug delivery system is also demonstrated by the loading and release of several clinical drugs. With the capability of penetrating biological barriers and delivering drugs, LCN provides a potential platform for disease treatments, particularly for those suffering from inadequate drug penetration.