bluuebunny/crossref_metadata_2025 huggingface dataset:
Searching for the nature of motor speech control: Vowel reduction in habitually slow versus fast talkers
Authors: Tsao Ying-Chiao , Weismer Gary
Published: July 2002

Vowel reduction as a function of speaking rate within individuals has been well established (Fourakis, 1991; van Bergem, 1995; Weismer et al., 1995). This phenomenon is challenged by the finding that differences exist in the control of speech rate for both slow and fast talker groups (see Tsao, 1995). This study will therefore examine vowel reduction in the speech of individuals separated on the rate continuum (i.e., slow versus average versus fast). The hypothesis that the habitual vowel spaces and the rate-induced degree of vowel reduction is different for habitually slow versus fast talkers will be explored. Subjects will produce a reading passage, and vowel reduction will be measured based on the target frequencies for F1, F2, and F3 for the four corner vowels (e.g., /a/, /i/, /ae/, /u/). A linear ergression function will be used to demonstrate the relationship between vowel reduction of the 60 subjects (15 slow, 15 fast, and 30 average) and their habitual speech rate along the rate continuum. [Work supported by University of Nebraska—Kearney and UW—Madison Speech Acoustics Laboratory.]
Prosodic phrasal structure and lexical interpretation
Authors: Speer Shari R. , Schafer Amy
Published: July 2002

In phonological theory, phonological phrases (PPhs) and intonational phrases (IPhs) are distinct levels of prosodic phrasing, with different edge tones, different constraints on well-formedness, and different acoustic properties. Although many studies have demonstrated prosodic effects on syntactic processing, few studies have examined prosodic effects on semantic processing, and the majority of studies have not compared the effects PPhs and IPhs [but see Kjelgaard (1995)]. It is demonstrated that, with respect to the interpretation of lexical, syntactic, and semantic ambiguities, PPhs and IPhs have distinct processing effects. Results will be presented from several experiments testing lexical ambiguities of several types, using both cross-modal naming and end-of-sentence tasks. For example, it will be shown that reanalysis to the subordinate meaning of a polysemous word presented in a neutral context takes longer when the word is in a preceding IPh than in a preceding PPh, for lexically and syntactically identical materials. These results indicate that prosodic phrasing influences the ambiguity resolution process at lexical, syntactic, and semantic levels. It is argued that the sentence comprehension mechanism makes differential use of two levels of prosodic phrasing specified in phonological theory. Implications for current processing models will be discussed. [Work supported by NIMH.]
Evidence for a second laryngeal sound source
Authors: Castellanos P. F. , Elder S. A.
Published: July 2002

Sondhi reflectionless tube and strobed video have been used to investigate single glottal pulse gestures in the vocal fry range. There appear to be two sources of sound in normal VF phonation, one monopole, the other quadrupole. It is quadrupole sound, in fact, that seems to define the shape of observed pressure trace in the single glottic pulse, or SGP. This sound pulse, which lasts 10 ms or less, resembles a single cycle of negative sine wave beginning just before the closing phase, and may be recognized even in sound emissions outside the tube, where continuous tone samples can be identified as SGP wave trains, each link beginning with a characteristic downturn. Monopole sound, emitted in shorter pulses during the abrupt zipping and sometimes during unzipping phases of the SGP, shows up along the main wave trace in the Sondhi tube as a small superposed peak, followed by a string of head echoes. The source of quadrupole sound can be traced to fluctuating Bernoulli pressures during closure which produce opposing forces on the vocal folds. The quadrupole or q-wave forms the acoustic signature of the SGP.
Fluid dynamic studies of speech production
Authors: Sinder D. , Krane M. , Chennoukh S. , Richard G. , Flanagan J. , Levinson S. , Slimon S. , Davis D.
Published: July 2002

Results are presented describing an investigation of aerodynamic sources in the vocal tract. The expected contribution of this study is a new parametrization for fricative sources based on geometric and flow conditions. The flow in an idealized fricative geometry is computed numerically using a slightly compressible, Reynolds-averaged form of the Navier–Stokes equations. In this formulation, the aerodynamic sources of sound are simulated with minimal approximation. This approach has produced encouraging results for vowel sounds. Comparisons of the computational results with physical experiments using the same geometry have also been performed. The results shed light on the source mechanisms for fricative sounds and also show the need for the development of numerical boundary conditions which can simultaneously handle convective and propagative phenomena. [Research supported by NSF/ARPA IRI-9314946 and ARPA DAST 63-93-C-0064.]
Analysis of selected data from a recent Navy exercise
Authors: Chin-Bing Stanley A. , King David B. , Norton Guy V. , Novarini Jorge C.
Published: July 2002

Several ocean acoustic computer models were used to analyze shallow-water, higher-frequency (around 4-kHz) acoustic data taken during a recent Navy exercise. This effort enlisted models (EFEPE-CM, FEPE, ASTRAL, RAYMODE) and computer resources (Cray C90, SGI Challenge-8, 386 desktop PC) that spanned the RDT&E modeling spectrum, from basic research to Fleet operations. The research models were used to identify and prioritize dominant physical mechanisms. Once these were known, errors and weaknesses in the operational models were easily identified and corrected. The result was consistent with predictions from the entire suite of models that compared favorably with data. Advantages were gained in computational speed and accuracy. An acceptable shallow-water, high-frequency, acoustic prediction was obtained in 2 s using a Fleet operational model (ASTRAL) and a 386 desktop PC computer. Two important lessons were relearned: (1) Current ocean acoustic research models include the necessary physics to make accurate high-frequency predictions in shallow-water environments, even when realistic sea-surface conditions dominate; and (2) the more physics included in the models, the less knowledgeable need be the model operators. Details and examples will be presented. [Work supported by ONR/NRL, MMoDS, AUAMP, and DoD HPC.]
A moraic duration in speech processing in Japanese
Authors: Otake Takashi , Yoneyama Kiyoko
Published: July 2002

Although it is often recognized that morae per se can be defined both phonetically and phonologically in the literature, it is not well understood how they are involved with each other in Japanese speech processing. Recent off-line studies have suggested that recognition of morae in Japanese is highly involved with duration and syllable position [Otake and Yoneyama, ICSLP 94 3, 1427–1430 (1994); ICPhS 95, 2, 686–689 (1995)]. In the present study, the duration of C1V1 and V2.C3V3 segments in C1V1.C2V2.C3V3 nonsense words where C2 is a nasal with three different speech rates was manipulated in order to see whether C2, an onset nasal, can be recognized as a moraic nasal depending upon preceding and following segmental duration. The materials were presented to 15 Japanese listeners to dictate what they heard in Roman characters. The results showed that the manipulation of C1V1 duration never caused C2 to be recognized as a moraic nasal, while V2C3V3 duration did. The shorter the V2.C3V3 were, the more C2 were recognized as a maraic nasal. This suggests that a moraic duration is not absolute, but relative to following segments. [Work supported by the Japanese Ministry of Education.]
The concept of stability and expectation in tonal music
Authors: Van Egmond Rene
Published: July 2002

There are two important aspects when listening to Western tonal music: the recognition of structures and the way expectations in music are evoked. Although these two aspects are not independent it can be argued that the first aspect relates to the listener’s sense of coherence in a piece, whereas the second aspect relates to the listener’s sense of a dynamic flow. Both aspects are dependent on the underlying feature of tonality, which has its fundamentals in the acoustical properties of sounds (overtone series) and the set theoretical properties of ‘‘musical scales.’’ The primary focus will be on the expectations of listeners given a certain key (i.e., tonal expectations). In literature it is assumed that these expectations rely on the ‘‘mental stability’’ associated with tones in a certain key (represented by the so-called tonal hierarchy). It is often argued that the difference in stability relates to a tonal expectation for a listener. Problems with this approach are discussed, considering music theoretical literature and data from experimental literature, especially emphasizing the difference between the function of individual tones and the harmonic related functions. Furthermore, data will be presented from newly performed experiments that test expectations in tonal music.
Is ‘‘plasticity’’ a useful construct in behavioral studies of auditory processing?
Authors: Watson Charles S.
Published: July 2002

Recently the term ‘‘plasticity’’ has been used in discussions of certain changes in human listeners’ abilities to detect, discriminate, and identify simple and complex sounds. In some cases this appears to be merely an effort to use language appropriate to the Zeitgeist. To conclude that any specific neuroanatomical or neurophysiological change is responsible for improved or changed psychophysical performance requires that physiological measurements be made on the same subjects before and after the behavioral changes occur. That is rarely done. There are, however, useful contributions to the understanding of neural plasticity that might be made by a thorough study of the time course of auditory perceptual learning for various tasks and classes of stimuli. More relevant psychophysical data can be collected when long periods of training on a single psychophysical task are followed by tests on other tasks, making it possible to estimate the range of stimuli and tasks to which the learning has generalized. Studies meeting these criteria demonstrate great variation in the time course of auditory learning and in its specificity. [Prepared with the support of NIH/NIDCD.]
Changes in auditory localization responses are mediated by visual input
Authors: Shinn-Cunningham Barbara G. , Park John
Published: July 2002

Previous studies have shown that, with training, subjects can learn a new relationship between spatial auditory stimuli and location [Shinn-Cunningham et al., J. Acoust. Soc. Am. 92, 2334(A) (1994); 95, 2896(A) (1994)]. These earlier studies involved training in which subjects turned to face a heard and seen target source, followed by testing using a simple forced-choice identification paradigm. In the current study, subject localization was tested using a head-pointing response method. The amount of visual information available to the subject during training and testing was systematically varied. It was found that when subjects were blindfolded, they showed no changes in localization performance over time; however, if subjects were provided with a visual field, adaptation was achieved. These results are consistent with the hypothesis that the felt position of the head is not an adequate cue to allow subjects to relearn localization responses, but that the addition of the visual field provides more robust information about the instantaneous position of the head so that learning can take place. [Work supported by the AFOSR.] a)Currently at the Department of Cognitive and Neural Systems, Boston University.
Analysis of children’s speech. Pitch and formant frequency
Authors: Lee Sungbok , Potamianos Alexandros , Narayanan Shrikanth
Published: July 2002

Pitch and formant measurements were performed on ten monophthongs of American English included in a speech database collected from 436 children (ages 5–18) and 56 adults [J. D. Miller et al., ICASSP, pp. 849–852 (1996)]. After automatic segmentation and labeling of each waveform, the pitch and the first four formant frequencies of each vocalic segment were estimated using a formant-tracking program (Entropic Research Laboratory, Inc.). Median values of each pitch and formant track were computed as the representative value of the track. The raw formant data were refined based on the linear regression statistics of each formant track and manual correction. The pitch and refined formant data were analyzed as a function of vowel, age, and gender. Results indicate that the rapid change in male pitch due to puberty occurs from age 12 to age 15, lower than the range (ages 13–17) in Kent [R. D. Kent, J. Speech Hear. Res. 19, 421–447 (1976)]. Age-dependent formant changes are explained by a linear scaling of the vocal tract length. The intra-subject variation of formant and pitch decreases as a function of age, supporting the results of a previous study [S. Eguchi and I. J. Hirsh, Acta Otolaryng., Suppl. 257 (1969)]. Implications of these and other findings on speech development will be discussed. [Work supported by AT&T.]
Detection of surface defects in bearings using electromagnetic flux
Authors: Bradley Ellen , Swanson David C.
Published: July 2002

The electromagnetic flux of rotating ball bearings was measured by a gradiometer-configured inductance coil. Ball spin, and drive and slave ring frequencies are distinguishable throughout the testing. One bearing was tested for 22 h, 45 min without reaching the failure, and the second bearing test involved restarting a bearing that had already reached the failure level but showed minimal visible damage. The first test showed increased magnetization of the bearing via an increase in flux at the spin frequency by 14 dB. The second test showed a consistent level of flux at the spin frequency compared to the final level detected in the first test. As the surface of the bearing becomes damaged from skidding, an increase in the magnetic field is hypothesized to originate from the abrased ferrous surfaces. The spinning ball allows this feature to be detected easily by a simple coil of wire. [See NOISE-CON Proceedings for full paper.]
Impulse responses and effective lengths for brass instruments
Authors: Ayers R. Dean
Published: July 2002

A brass instrument has three major parts: an input segment, a cylindrical or conical central segment, and a bell. (The latter two are often treated together.) It is conceptually useful to isolate the input segment from the rest of the air column and study the acoustical behavior of that complete segment rather than its components. Features in time- and frequency-domain plots can be correlated very easily with each other and with the physical structure. Combining the input segment’s time-domain behavior with that for the rest of the air column yields some novel impulse responses for use with any model of the lip reed [R. D. Ayers, J. Acoust. Soc. Am. 100, 1190–1198 (1996)]. In the frequency domain, effective lengths for the input segment and the rest of the air column can be combined to give a useful indicator for the degree of harmonic alignment among the input impedance peaks [R. D. Ayers, J. Acoust. Soc. Am. 98, 81–87 (1995)]. Specific examples in both domains will be discussed.
Exploitation of vibration and noise signals cyclostationarity in condition based maintenance
Authors: Vokurka Karel
Published: July 2002

A traditional approach to the analysis of vibration and noise in condition based maintenance of machinery is to assume stationarity of the measured signals. However, in the case of machinery working cyclically (e.g., gearboxes, engines, turbines) the generated vibration and noise are basically nonstationary (cyclostationary). This feature, in the traditional approach partially suppressed by continuous time averaging, can be exploited to give more detailed information on the condition of the monitored machinery. To achieve this, periodic time averaging is used. In this paper, the second-order statistical characteristics of the cyclostationary signals are considered. These are double correlation functions, double autospectral densities, and instantaneous autospectra. The disadvantage of these statistical characteristics is their greater complexity. However, they yield a more detailed description of measured signals. Another advantage is a greater immunity to interfering signals. Algorithms for computation of the characteristics will be presented. Theoretical conclusions will be demonstrated on a concrete example of vibration data measured on a passenger car gearbox. [Work supported by the Grant Agency of the Czech Republic.] [See NOISE-CON Proceedings for full paper.]
Bearing cage fault detection using bandwidth-weighted demodulation
Authors: Li C. James
Published: July 2002

When faults occur in bearing cages, they generate an extremely wideband fault signature modulated by the cage rotating frequency as the defective part of the cage rotates in and out of the load zone. Current bearing fault detection methods, which were developed for race and rolling element defects, are aimed at isolating and demodulating relatively powerful high-frequency, narrow-band ringing vibrations, and therefore have difficulty detecting bearing cage faults. Bandwidth-weighted demodulation (BWD), however, is well suited to cage faults because it is more sensitive to wideband, low-power signal modulations than to narrow-band, high-power signal modulations. A bearing cage fault detection algorithm has been established based on BWD. The effectiveness of BWD compared to other methods is demonstrated in simulation and confirmed using experimental data from a failed bearing. [See NOISE-CON Proceedings for full paper.]
Investigation of an annular thermoacoustic prime mover
Authors: Lin Hsaio-Tseng , Muehleisen Ralph T. , Atchley Anthony A.
Published: July 2002

The study of an annular thermoacoustic prime mover has been presented at a previous meeting [Lin et al., J. Acoust. Soc. Am. 100, 2846(A) (1996)]. The prime mover described there was unable to reach onset. As a result of improved analysis, the design has been simplified. The resonance frequencies and quality factor of the new prime mover were measured as functions of the temperature difference imposed across the stack. The experimental work is presented and a numerical model based on an iterative method is proposed. [Work is supported by the Office of Naval Research and the American Society of Engineering Education.]
Passive low-frequency acoustical method of nondestructive testing of the energetic systems
Authors: Gelman Leonid M.
Published: July 2002

The new preventive passive low-frequency acoustical method of nondestructive testing of the energetic bladed systems is considered. The proposed method is based on reception, processing, and estimation of parameters of the energetic bladed system’s own acoustic noise in a low-frequency range (0.002–50 kHz) with the usage information about rotation frequencies of rotors. The method includes the following procedures: (1) detection of the narrow-band acoustic signals on the background of interference; (2) identification of the detected acoustic signals; and (3) estimation of testing date and decision acceptance of the state of the energetic bladed system stages. The method allows for acceptance of the state at the appropriate stage of the energetic system in maintenance when the stage is in a normal state, or when the stage is in a state before damage. Experimental results are presented. The proposed method represents one of the approaches to efficient energy use and conservation.
The long-time average spectra of newborn infant crying
Authors: Goberman Alexander M. , Robb Michael P.
Published: July 2002

The majority of research pertaining to acoustic analysis of infant crying is based on the collection of a limited number of cry segments. Far less research is based on examination of whole crying episodes. Long-time average spectrum (LTAS) analysis offers a quantitative approach to inferring the vocal source as derived from whole crying episodes. The purpose of this study was to quantitatively examine a variety of LTAS characteristics (e.g., energy concentrations, spectral tilt) in the crying episodes of ten normal full-term neonates and ten at-risk preterm neonates. Results of this analysis indicated that some but not all of the LTAS features were discriminating of normal versus at-risk infants. The discussion focuses on the application of cry analysis in the evaluation of laryngeal behavior and its potential usefulness in determining an infant’s health status.
Design procedures for synthetic aperture sonar
Authors: Kooij Theo
Published: July 2002

An engineering approach is presented for the top down design of synthetic aperture sonar (SAS) systems. The principal system parameters and the equations governing their relations will be identified. The difference between the variables and the equations determines the number of free variables, which can be selected either arbitrarily or according to the system requirements. Some simple rules will be stated, and by example it will be shown how to apply the design steps.
Space and frequency dependence in low-frequency, narrow-band bistatic reverberation: Theoretical results for variable wind speed and surface directionality
Authors: Gragg Robert F.
Published: July 2002

Analytical methods are used to express the dependence of low-frequency bistatic reverberation on the power and direction spectra of the time-dependent sea surface. The 3-D cross-spectral density (CSD) of the reverberation is obtained, to second order in the small-waveheight approximation, as a sum of dc and sideband terms. For numerical simulations, this theoretical formulation is applied to a model ocean consisting of a homogeneous half-space. The sensitivity of the CSD to the power spectrum of the source, the power and direction spectra of the surface, and bistatic source/receiver geometry are assessed for both the zero-Doppler components and the Bragg–Doppler sidebands. [Work supported by ONR.]
Categorical perception as a function of stimulus quality.
Authors: van Hessen A. J. , Schouten M. E. H.
Published: July 2002

A number of experiments were carried out in order to test the hypothesis that the degree of categorical perception of speech stimuli is a function of synthesis quality; specifically, that the greater complexity of more natural speech stimuli makes it difficult for listeners to focus on particular stimulus parameters such as psychoacoustic cues. The results show that there is some increase in categorical perception as synthesis quality improves from a simple synthesis by rule, via LPC synthesis, to a much more complex type called sine-wave generation.
Full-wave simulation of the forward scattering of sound in a structured ocean: A comparison with observations
Authors: Wolfson Michael A. , Spiesberger John L.
Published: July 2002

The propagation of a 133±16-Hz acoustic signal through the eastern North Pacific Ocean is simulated over basin-scale ranges. A high angle c0-insensitive parabolic equation model is used for the simulations. The ocean environment was constructed using CTD data or climatologically averaged data from the Levitus database, along the geodesic from Kaneohe, near Oahu to the receiver, located 3709 km to the northeast. A projection of a three-dimensional frozen internal wave field is superposed. The stable earlier arrivals measured from experimental data were used as a reference anchor, and it is demonstrated that internal wave energy in addition to mesoscale structure is responsible for vertically scattering the late ‘‘axial’’ acoustic energy over 1 km.
Numerical simulation of jagged-edge noise barriers
Authors: Ohm Won-Suk , Blackstock David T. , Busch-Vishniac Ilene J.
Published: July 2002

The performance of a jagged-edge noise barrier (thin, infinitely long) is investigated numerically. The source is a spherical N wave. The theoretical approach is to treat the incident field in the plane above the barrier as a plane piston radiator (Kirchhoff approximation). Numerical calculation gives the radiated field (pressure time waveform) at any point in the shadow zone. A discrete Fourier transform then yields the spectrum. The numerical result for a straight barrier compares favorably with the asymptotic result of U. J. Kurze [J. Acoust. Soc. Am. 55, 504–518 (1974)]. Because of the intrinsic limitation imposed by the Kirchhoff approximation, however, the numerical method does not give accurate results when the listener is deep in the shadow zone. For the jagged-edge barrier, the numerical simulation confirms the experimental findings of Ho et al. [J. Acoust. Soc. Am. 101 (to be published 1997)] in that making the barrier edge jagged (1) increases the insertion loss at high frequencies, but (2) degrades the performance somewhat at low frequencies. Suggestions for improving the insertion loss formula of Ho et al. for a jagged-edge barrier are also made. [Work supported by the Texas Advanced Technology Program.]
High-frequency bistatic scattering by sub-bottom gas bubbles
Authors: Chu Dezhang , Williams Kevin L. , Tang Dajun , Jackson Darrell R.
Published: July 2002

A previous study of high-frequency acoustic backscattering data collected at Eckernfoerde Bay, Germany revealed that scattering is mainly due to methane gas bubbles buried about a meter beneath the seafloor [Tang et al., J. Acoust. Soc. Am. 96, 2930–2936 (1994)]. A backscattering model was developed [Tang, Geo-Marine Lett. 16, 161–169 (1996)] where the gas bubbles were approximated by oblate spheroids. In this paper, a bistatic scattering model is proposed as an extension of the previously developed backscattering model. In this model, gas bubbles are again assumed to be oblate spheroids with varying aspect ratios and a single-scattering approximation is used. The model is compared to bistatic data acquired in Eckernfoerde Bay, Germany. In particular, the azimuthal dependence of the bistatic scattering strength predicted by the model is tested against experimental data and it is found that both the model and the bistatic scattering strength data exhibit a mild azimuthal dependence. Best agreement between model and data requires a 35% reduction in areal bubble density relative to that used in the backscattering model/data comparison. Possible reasons for this are discussed including multiple scattering effects.
The effects of click level, click rate, and level of background masking noise on the inferior colliculus potential (ICP) in the normal and carboplatin-treated chinchilla
Authors: Burkard Robert , Trautwein Patricia , Salvi Richard
Published: July 2002

Carboplatin produces a selective loss of inner hair cells in chinchilla, substantially reducing the amplitude of the compound action potential. A key question that arises from these experiments is: What effect does a reduction in IHC-eighth-nerve fiber input have on the central auditory nervous system? This investigation evaluated the inferior colliculus potential (ICP) in chinchillas treated with carboplatin. The left ear was surgically destroyed and a recording electrode was placed in the left inferior colliculus. Following thirteen days of recovery time, the ICP was recorded in the awake animal. Click level was varied from 10–20 to 80 dB pSPL. Click rate was varied from 10 to 1000 Hz using both conventional averaging and a cross-correlation procedure. Broadband masking noise was varied from 30 to 70 dB SPL with click level held constant at 80 dB pSPL. The dependent variables were the positive peak latency and peak-to-following trough amplitude of the evoked potential. Following baseline studies, the animals were administered carboplatin (50 mg/kg IP) and retested two weeks later. Prior to carboplatin administration, there was an increase in ICP latency and a decrease in ICP amplitude with decreasing stimulus level, increasing rate and increasing noise level. Mean ICP threshold was 30 dB pSPL. Following carboplatin administration, there was little change in threshold or peak latencies. In contrast, the amplitude of the ICP was reduced on average by one-third, although this effect varied considerably across animals. The magnitude of this amplitude decrement was not strongly dependent on click level, click rate, or the level of background noise.
Frequency-dependent enhancement of basilar membrane velocity during olivocochlear bundle stimulation
Authors: Dolan David F. , Guo Meng He , Nuttall Alfred L.
Published: July 2002

Basilar membrane (BM) velocity responses were measured in the presence of olivocochlear bundle (OCB) stimulation. Frequency threshold tuning curves (FTCs) were derived from tone-evoked input–output (I/O) functions. Efferent nerve activation produced decreases in velocity amplitude for frequencies around best frequency (BF) at low stimulus levels with little or no effect for stimuli well below the BF. A level-dependent efferent reduction/enhancement of BM velocity was found for certain stimulus frequencies above the BF. Efferent activation either had no effect or caused small reductions in the velocity response produced by low level sound, whereas, at higher stimulus levels, efferent activation increased the velocity response. The derived FTCs, therefore, showed criterion-dependent changes with efferent activation. For low BM criterion velocities, FTCs showed the classic desensitization of the tip region without a shift of BF. Some BM velocity criterion values showed FTCs with an expanded high-frequency response area, also without a shift of BF. The results suggest that the effect of OCB activation changes the gain of the voltage-dependent outer hair cell motility such that BM velocity response near BF is decreased while increasing the response for tones well above BF.
Ultrasonic wave generation by time-gated microwaves
Authors: Hosten Bernard , Bernard Pierre Alain
Published: July 2002

This paper shows how the energy transfer between electromagnetic waves and elastic waves at the surface of fluid or solid materials could constitute a new way to generate ultrasonic waves without contact for the purpose of nondestructive evaluation and control. When time-gated microwaves strike the surface of a material, there is a generation of ultrasonic waves. The times-of-flight of these elastic waves inside the material decrease when the power of the incident microwaves increases. Therefore, the diminution of the propagation path indicates that the energy transformation appears in a volume close to the surface, the depth of which is increasing along with the power of the microwaves and depends on the material properties. Consequently, the elastic wave generation is attributed to the evolution of the power of the microwave during the gate width that governs the frequency content of the ultrasonic waves. The generation of ultrasound is checked in water and polymers. If the microwaves are not too attenuated in the material, the ultrasonic waves can be generated both at input (air–solid) and output (solid–air) interfaces. These peculiarities can generate new applications in the nondestructive evaluation and control of material.
Multivariable feedback active structural acoustic control using adaptive piezoelectric sensoriactuators
Authors: Vipperman Jeffrey S. , Clark Robert L.
Published: July 2002

An experimental implementation of a multivariable feedback active structural acoustic control system is demonstrated on a piezostructure plate with pinned boundary conditions. Four adaptive piezoelectric sensoriactuators provide an array of truly colocated actuator/sensor pairs to be used as control transducers. Radiation filters are developed based on the self- and mutual-radiation efficiencies of the structure and are included into the performance cost of an H2 control law which minimizes total radiated sound power. In the cost function, control effort is balanced with reductions in radiated sound power. A similarity transform which produces generalized velocity states that are required as inputs to the radiation filters is presented. Up to 15 dB of attenuation in radiated sound power was observed at the resonant frequencies of the piezostructure.
The mobility functions and their application in calculating power flow in coupled cylindrical shells
Authors: Ming R. S. , Pan J. , Norton M. P.
Published: July 2002

The mobility functions of semi-infinite and finite cylindrical shells are useful in calculating the structural wave power flows in coupled pipeline systems. However, their expressions and characteristics are not available in the existing literature. In this paper, the mobility functions of elastic cylindrical in vacuo shells have been numerically studied and applied to estimate both the input power and the power flow in coupled finite cylindrical shell systems.
Deduction of ground impedance from measurements of excess attenuation spectra
Authors: Taherzadeh Shahram , Attenborough Keith
Published: July 2002

An efficient numerical method of deducing ground-surface impedance from measurements of short-range propagation from a point source is proposed. The method involves finding the root of a complex equation and uses the fact that the classical approximation for the spherical wave-reflection coefficient near grazing incidence is an analytic function of the impedance. Examples of fitting measured excess-attenuation spectra are given. Methods for ensuring the uniqueness of the resulting impedance fits are discussed. Subsequent deductions of parameters in a two-parameter impedance model are also considered and exemplified.
A model of auditory perception as front end for automatic speech recognition
Authors: Tchorz Jürgen , Kollmeier Birger
Published: July 2002

A front end for automatic speech recognizers is proposed and evaluated which is based on a quantitative model of the “effective” peripheral auditory processing. The model simulates both spectral and temporal properties of sound processing in the auditory system which were found in psychoacoustical and physiological experiments. The robustness of the auditory-based representation of speech was evaluated in speaker-independent, isolated word recognition experiments in different types of additive noise. The results show a higher robustness of the auditory front end in noise, compared to common mel-scale cepstral feature extraction. In a second set of experiments, different processing stages of the auditory front end were modified to study their contribution to robust speech signal representation in detail. The adaptive compression stage which enhances temporal changes of the input signal appeared to be the most important processing stage towards robust speech representation in noise. Low-pass filtering of the fast fluctuating envelope in each frequency band further reduces the influence of noise in the auditory-based representation of speech.
On a numerical truncation approximation algorithm for transfer matrix method
Authors: Balasubramaniam Krishnan
Published: July 2002

A numerical truncation technique is described for reducing the numerical instability problems associated with the utilization of the transfer matrix method, especially in cases where the frequency of ultrasound, the number of layers, or the thickness of the layers become very large. This rather simplistic modification to the numerical coding extends the transfer matrix method to a wide range of applications, without any complex and computationally intensive reformulation.
Experimental study of the liquid flow near a single sonoluminescent bubble
Authors: Verraes Tanguy , Lepoint-Mullie Françoise , Lepoint Thierry , Longuet-Higgins Michael S.
Published: July 2002

Tracers (sulphur particles produced in situ by a bubble itself, fuchsin spots and dust) were used to probe the liquid flows in the neighborhood of single sonoluminescent bubbles maintained in levitation in a resonant acoustic setup. The flows caused by the bubble were distinguished clearly from the streamings (mean Lagrangian velocity: ∼20 μm/s) associated with resonant cells in the absence of a bubble. The liquid flow due to the presence of the bubble formed around it over a few mm. The radial component of the Lagrangian velocities (maximum value measured: ∼260 μm/s) of this flow evolved as r−1, with r as the distance from the bubble, while the tangential component remained approximately constant (∼20 μm/s). In the Appendix by M. S. Longuet-Higgins, a simplified model of microstreaming involving a spherical bubble in translational and radial oscillation gives a qualitative description of the experiments. A fairly good agreement was observed between the experiments and the modeling, which involved a dipole flow enclosed in a Stokeslet.
A Modified Functional Expansion for Viscoelastic Fluids
Authors: Goddard J. D.
Published: July 2002

A rheological equation for viscoelastic fluids is derived as an expansion of Noll's functional for simple fluids. The present expansion is developed in terms of the deformation rate referred to a co-rotational material frame. The resulting series of approximations for the stress differs significantly from those proposed previously by Green and Rivlin and by Coleman and Noll. Applications to both simple-extensional and viscometric flows are considered. For viscometric flows the present model exhibits non-Newtonian effects similar to those observed in real fluids, with relatively few terms in the functional expansion. The first term in the expansion yields a “first-order” fluid similar to the model proposed by Pao. Expressions are also given for the viscometric material functions of the present “third-order” fluid. As with higher-order fluids, these functions are Fourier integrals of certain hereditary or memory functions for the fluid.
Elongational Viscosity of Nonlinear Elastic Dumbbell Suspensions
Authors: Stevenson James F. , Bird R. Byron
Published: July 2002

The Kramers method for analyzing bead-rod suspensions in potential flow has been extended to a suspension of inverse-Langevin-spring dumbbells in elongational flow. The elongational viscosity and root-mean-square bead separation for two different inverse-Langevin-spring models are calculated numerically and presented in graphical form. The numerical calculations for one model are in excellent agreement with similar, approximate calculations made by Peterlin. For linear (Hookean and Fraenkel) spring models with finite spring constants, the elongational viscosity and mean-square bead separation are unbounded, but for both inverse-Langevin-spring models these quantities approach an upper bound with increasing elongation rate.
Size effects on the shear-thickening behavior of suspensions flocculated by polymer bridging
Authors: Otsubo Yasufumi
Published: July 2002

The polymer coil whose size is comparable in solution to particle diameter makes a flexible bridge between two particles. The suspensions flocculated by the bridging mechanism show shear thickening at high shear rates when both the particle and polymer concentrations are increased above some critical levels. The boundary for appearance of shear thickening is analyzed in terms of a percolation process. The shear thickening results from the three-dimensional network structure consisting of particles bridged by flexible polymer coils. Since the intrinsic mechanism of shear thickening is the restoring forces of extended bridges in shear fields, the most important variable affecting the flow behavior is bridging conformation. The effects of particle and coil sizes on the shear-thickening behavior are examined in relation to bridging conformation. The shear thickening takes place for suspensions prepared using particles with diameters of 80–125 nm and polymers with molecular weights of 2.5×105–4.5×105. The appearance of shear thickening is determined by a delicate balance between flexibility of bridge and adsorption affinity.
Association of Pack-Years of Cigarette Smoking With Survival and Tumor Progression Among Patients Treated With Chemoradiation for Head and Neck Cancer
Authors: Ma Sung Jun , Yu Han , Yu Brian , Waldman Olivia , Khan Michael , Chatterjee Udit , Santhosh Sharon , Gill Jasmin , Iovoli Austin J. , Farrugia Mark , Shevorykin Alina , Carl Ellen , Wooten Kimberly , Gupta Vishal , McSpadden Ryan , Kuriakose Moni A. , Markiewicz Michael R. , Al-Afif Ayham , Hicks Wesley L. , Platek Mary E. , Seshadri Mukund , Sheffer Christine , Warren Graham W. , Singh Anurag K.
Published: December 2022

Importance

After 10 pack-years of smoking was initially established as a threshold for risk stratification, subsequent clinical trials incorporated it to identify candidates for treatment deintensification. However, several recent studies were unable to validate this threshold externally, and the threshold for smoking exposure remains unclear.

Objective

To estimate the threshold of pack-years of smoking associated with survival and tumor recurrence among patients with head and neck cancer.

Design, Setting, and Participants

This single-institution, cohort study included patients with nonmetastatic head and neck cancer receiving chemoradiation from January 2005 to April 2021. Data were analyzed from January to April 2022.

Exposures

Heavy vs light smoking using 22 pack-years as a threshold based on maximizing log-rank test statistic.

Main Outcomes and Measures

Overall survival (OS), progression-free survival (PFS), locoregional failure (LRF), and distant failure (DF).

Results

A total of 518 patients (427 male [82.4%]; median [IQR] age, 61 [55-66] years) were included. Median (IQR) follow-up was 44.1 (22.3-72.8) months. A nonlinear Cox regression model using restricted cubic splines showed continuous worsening of OS and PFS outcomes as pack-years of smoking increased. The threshold of pack-years to estimate OS and PFS was 22. Cox multivariable analysis (MVA) showed that more than 22 pack-years was associated with worse OS (adjusted hazard ratio [aHR] 1.57; 95% CI, 1.11-2.22; P = .01) and PFS (aHR, 1.38; 95% CI, 1.00-1.89; P = .048). On Fine-Gray MVA, heavy smokers were associated with DF (aHR, 1.71; 95% CI, 1.02-2.88; P = .04), but not LRF (aHR, 1.07; 95% CI, 0.61-1.87; P = .82). When 10 pack-years of smoking were used as a threshold, there was no association for OS (aHR, 1.23; 95% CI, 0.83-1.81; P = .30), PFS (aHR, 1.11; 95% CI, 0.78-1.57; P = .56), LRF (aHR, 1.19; 95% CI, 0.64-2.21; P = .58), and DF (aHR, 1.45; 95% CI, 0.82-2.56; P = .20). Current smoking was associated with worse OS and PFS only among human papillomavirus (HPV)-positive tumors (OS: aHR, 2.81; 95% CI, 1.26-6.29; P = .01; PFS: aHR, 2.51; 95% CI, 1.22-5.14; P = .01).

Conclusions and Relevance

In this cohort study of patients treated with definitive chemoradiation, 22 pack-years of smoking was associated with survival and distant metastasis outcomes. Current smoking status was associated with adverse outcomes only among patients with HPV-associated head and neck cancer.
Coupling of binding and differential subdomain folding of the intrinsically disordered transcription factor CREB
Authors: Bentley Emily P. , Scholl Daniel , Wright Peter E. , Deniz Ashok A.
Published: December 2022

The cyclic AMP response element binding protein (CREB) contains a basic leucine zipper motif (bZIP) that forms a coiled coil structure upon dimerization and specific DNA binding. Although this state is well characterized, key features of CREB bZIP binding and folding are not well understood. We used single‐molecule Förster resonance energy transfer (smFRET) to probe conformations of CREB bZIP subdomains. We found differential folding of the basic region and leucine zipper in response to different binding partners; a strong and previously unreported DNA‐independent dimerization affinity; folding upon binding to nonspecific DNA; and evidence of long‐range interdomain interactions in full‐length CREB that modulate DNA binding. These studies provide new insights into DNA binding and dimerization and have implications for CREB function.
X‐ray Tomography and Tomoscopy on Metals: A Review
Authors: García-Moreno Francisco , Neu Tillmann Robert , Kamm Paul Hans , Banhart John
Published: December 2022

X‐ray tomography is a versatile tool in materials research and engineering since it allows for a non‐destructive and three‐dimensional mapping of the constituents of a heterogeneous material as long as they differ in their interactions with X‐rays. Recent developments of the technique have brought down the time needed for the acquisition of a single tomogram by many orders of magnitude compared to what was needed 25 years ago. Nowadays, up to 1000 full tomograms can be recorded in a second, which enables real‐time studies of changes in samples caused by reactions or by applied processing operations. The term tomoscopy has been coined for such sequences of 3D images. We review the application of X‐ray tomography and tomoscopy on metals and describe each step required and the associated challenges. A selection of representative investigations is presented with a focus on time‐resolved phenomena in metals and alloys ranging from mechanical deformation, solidification to metals processing processes such as welding and additive manufacturing. Finally likely future developments are discussed.
Lightweight, Thermally Insulating, Fire‐Proof Graphite‐Cellulose Foam
Authors: Chen Chaoji , Zhou Yubing , Xie Weiqi , Meng Taotao , Zhao Xinpeng , Pang Zhenqian , Chen Qiongyu , Liu Dapeng , Wang Ruiliu , Yang Vina , Zhang Huilong , Xie Hua , Leiste Ulrich H. , Fourney William L. , He Shuaiming , Cai Zhiyong , Ma Zhenqiang , Li Teng , Hu Liangbing
Published: December 2022

Foam materials are widely used in packaging and buildings for thermal insulation, sound absorption, shock absorption, and other functions. They are dominated by petroleum‐based plastics, most of which, however, are not biodegradable nor fire‐proofing, leading to severe plastic pollution and safety concerns. Here, a fire‐proofing, thermally insulating, recyclable 3D graphite‐cellulose nanofiber (G‐CNF) foam fabricated from resource‐abundant graphite and cellulose is reported. A freeze‐drying‐free and scalable ionic crosslinking method is developed to fabricate Cu2+ ionic crosslinked G‐CNF (Cu‐G‐CNF) foam with a low energy consumption and cost. Moreover, the direct foam formation strategy enables local foam manufacturing to fulfil the local demand. The ionic crosslinked G‐CNF foam demonstrates excellent water stability (the foam can maintain mechanical robustness even in wet state and recover after being dried in air without deformation), fire resistance (41.7 kW m−2 vs 214.3 kW m−2 in the peak value of heat release rate) and a low thermal conductivity (0.05 W/(mK)), without compromising the recyclability, degradability, and mechanical performance of the composite foam. The demonstrated 3D G‐CNF foam can potentially replace the commercial plastic‐based foam materials, representing a sustainable solution against the “white pollution”.
Metal Oxide/Graphene/Metal Sandwich Structure for Efficient Photoelectrochemical Water Oxidation
Authors: Xie Guancai , Guo Beidou , Gong Jian Ru
Published: December 2022

Single‐layer graphene (SLG) has drawn considerable interest in photoelectrochemical (PEC) cells due to its atomically flat pinhole‐free structure and remarkable in‐plane carrier mobility. It is challenging, however, to obtain efficient SLG‐modified photoelectrodes for PEC water splitting mainly due to the inefficient charge transfer interface. Here, a transition metal oxide/SLG/transition metal sandwich structure modified n‐Si‐based model photoanode is constructed to regulate the interfacial charge transfer behavior for enhanced PEC water oxidation performance. In this sandwich configuration, SLG tailors the morphology, structure, and work function properties of surface metal electrocatalysts to obtain both higher thermodynamic photovoltage and faster kinetical charge transfer at the semiconductor/electrolyte interface. In addition, SLG promotes the surface catalytic reaction as an effective charge trap and storage layer. This study provides a new structural design to engineer the SLG interfacial properties for high‐performance energy conversion devices.