bluuebunny/crossref_metadata_2025 huggingface dataset:
Who Does the Public Trust? The Case of Genetically Modified Food in the United States
Authors: Lang John T. , Hallman William K.
Published: October 2005

Trust is important for the perception of many types of risk, including those relating to genetically modified (GM) food. Who the public trusts in any given circumstance, however, is not well understood. In this study of public trust regarding GM food, an exploratory factor analysis with Promax rotation reveals public classification of three common institutional types—evaluators, watchdogs, and merchants. The structure of relationships among these stakeholders can act to enable or constrain public support for this new technology. Evaluators—scientists, universities, and medical professionals—are the most trusted. Watchdogs—consumer advocacy organizations, environmental organizations, and media sources—are moderately trusted. Merchants—grocers and grocery stores, industry, and farmers—are least trusted. While the federal government is seen as closest to being an evaluator, it is not highly correlated with any of the factors. The lack of trust in the organizations with the greatest resources and responsibilities for ensuring the safety of GM food should be seen as an important obstacle to the adoption of the technology.
Risk of Bleeding Complications Is Not Increased in Patients Undergoing Rescue versus Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction
Authors: ELLIS KEITH , BOCCALANDRO FERNANDO , BURJONROPPA SUKESH , MUENCH ANDREAS , GIESLER GREGORY M. , SMALLING RICHARD W. , SDRINGOLA STEFANO
Published: October 2005

Background: Concern for major bleeding complications (MBC) may lead to withholding of anticoagulation and fibrinolytic therapy in preparation for primary percutaneous coronary intervention (PCI), potentially resulting in unacceptable delays in achieving reperfusion.

Objectives: The primary objective of this study was to evaluate MBC associated with primary and rescue PCI and how timing to revascularization affects this variable.

Methods: We evaluated 659 consecutive patients presenting within 24 hours of an acute ST elevation myocardial infarctions (MI). One hundred and eighty‐three patients presented for rescue PCI and 476 for primary PCI. Eighty‐seven rescue PCI patients were treated within 6 hours of their first dose of fibrinolytic. Demographics, procedural variables, outcomes, and major adverse cardiovascular events (MACE) were compared between the primary and rescue PCI groups and between early and late presenters in the rescue PCI group.

Results: We observed that the incidence of MBC was 8% in patients undergoing rescue PCI and 6% in primary PCI (P = 0.35). There were no significant differences in bleeding associated with GP IIb/IIIa receptor antagonist use, procedural success, or MACE. Similarly, in patients presenting for early or late rescue PCI there was no significant difference in MBC, procedural success, or MACE.

Conclusions: We concluded that early or late rescue PCI and primary PCI have similar rates of MBC and overall in‐hospital outcomes for patients presenting within 24 hours of acute MI. Delaying the timing of a rapid reperfusion strategy in an effort to decrease the incidence of MBC complications is generally not justified.
Chemical Interactions Between Cement and E‐Glass Fibers with a CaO–BaO–SiO2–TiO2 Coating
Authors: Wen Liang , Jijian Cheng , Yingjie Hu
Published: October 2005

E‐glass fibers were coated with a 15CaO–15BaO–20SiO2–50TiO2 thin film by the sol–gel method. Mechanical and chemical tests were performed on coated and uncoated fibers in cement and cement extract solutions to investigate the interactions between cement and gel‐glass film. The results show that the resistance of E‐glass fibers to the alkali cement medium is enhanced by the 15CaO–15BaO–20SiO2–50TiO2 coating. The significant roles of TiO2, CaO, and BaO in the protection fibers from the alkaline attack of cement are described. Some evidence is presented that the alkali corrosion of the coated fibers results in the formation of a thick and compact Ti film that suppresses further corrosion reaction.
Aging in Ferroelectrics
Authors: Lupascu Doru C. , Genenko Yuri A. , Balke Nina
Published: October 2005

The reorientation of defect dipoles and the drift of free charge carriers are the most prominent microscopic mechanisms under discussion to provoke the aging effect in ferroelectrics. These two mechanisms are contrasted taking into account the influence of grain boundaries in a polycrystalline material. For the drift model, clamping pressures on domain walls only depend on geometry and on the transport properties of the mobile defect charge carrier independent of its electronic or ionic nature. For a numerical example clamping pressures as a result of drift of oxygen vacancies are determined in BaTiO3. They range from 106 to 107 Pa corresponding to experimental values.
Electron Probe Micro Analysis of A‐Site Inter‐Diffusion Between LaFeO3 and NdFeO3
Authors: Smith Jens B. , Norby Truls , Fossdal Anita
Published: October 2005

The A‐site cation diffusion in LaFeO3 has been examined by inter‐diffusion experiments between LaFeO3 and NdFeO3. Dense, polycrystalline bodies were annealed in contact at temperatures between 1100° and 1300°C in ambient air. The bulk‐ and grain‐boundary inter‐diffusion coefficients were calculated from concentration profiles determined by electron probe micro analysis of cross sections. The bulk‐ and grain‐boundary inter‐diffusion coefficients showed Arrhenius‐type behavior with activation energies 610±30 and 600±100 kJ/mol, respectively. Based on the assumption of 1 nm thick grain boundaries the grain‐boundary inter‐diffusion coefficient was ∼4 orders of magnitude higher than the bulk inter‐diffusion coefficient.
Effect of CaF2 and CaO Substituted for MgO on the Phase Evolution and Mechanical Properties of K‐Fluorrichterite Glass Ceramics
Authors: Mirsaneh Mehdi , Reaney Ian M. , James Peter F. , Hatton Paul V.
Published: October 2005

Chain silicate glass ceramics based on K‐fluorrichterite (KNaCaMg5Si8O22F2, KFR) have potential for use in restorative dentistry and biomedical applications because they may be cast to shape and, when cerammed, have high biaxial flexural strength and fracture toughness. Excess CaO in canasite‐based chain silicate compositions is known to enhance their bioactivity. Therefore, two new glass ceramic compositions have been fabricated with 5 mol% CaF2 (Glass A) and 5 mol% CaO (Glass B) substituted for MgO in the KFR formula unit. The phase evolution of Glasses A and B was studied in detail using X‐ray diffraction and transmission electron microscopy. In addition, their mechanical properties were assessed. For Glass A, the fracture toughness (FT=2.66±0.02 MPa·m1/2) and biaxial flexural strength (BFS=227.3±24.5 MPa) were optimized for samples heat treated at 900°C for 4 h. In Glass B, however, the best FT (2.08±0.02 MPa·m1/2) and BFS (217.4±4.4 MPa) were obtained at 950°C. In view of their excellent mechanical properties and castability, Glasses A and B are considered potential candidates for fabrication of custom medical devices in restorative dentistry and moderate load‐bearing reconstructive bone surgery.
Phase Field Simulations of Hysteresis and Butterfly Loops in Ferroelectrics Subjected to Electro‐Mechanical Coupled Loading
Authors: Soh A. K. , Song Y. C. , Ni Y.
Published: October 2005

Two‐dimensional computer simulations of ferroelectric polarization switching have been performed using the phase field simulation model developed by employing the time‐dependent Ginsburg–Landau equations. The bulk‐free energy, polarization gradient energy, long‐range dipole–dipole electrostatic interactions, and elastic energy were taken into account in the above‐mentioned simulations. The influences of electric–mechanical coupled loading on the hysteresis and butterfly loops were studied. The results showed that the coupled electro‐mechanical loading could change both the coercive field of ferroelectric materials and the symmetry of hysteresis and butterfly loops.
Non‐syndromic multiple supernumerary teeth transmitted as an autosomal dominant trait
Authors: Batra P. , Duggal R. , Parkash H.
Published: October 2005

Supernumerary teeth are common in the general population and occur more frequently in‐patients with family history of such teeth. Multiple supernumerary teeth are associated with cleidocranial dyplasia and Gardner syndrome. However it is rare to find multiple supernumeraries in individuals with no other associated disease or syndrome. We describe the occurrence of multiple supernumerary teeth in a family occurring as a non‐syndromal trait. The autosomal dominant transmission of non‐syndromal multiple supernumerary teeth is new.
Medication Utilization Behavior in Patients Receiving Phosphodiesterase Type 5 Inhibitors for Erectile Dysfunction
Authors: Mulhall John P. , McLaughlin Trent P. , Harnett James P. , Scott Brian , Burhani Soraya , Russell David
Published: October 2005

Introduction

A number of preference studies have been conducted with phosphodiesterase type 5 (PDE5) inhibitor medications demonstrating inconsistent findings. Additionally, limited information is available regarding real-world utilization patterns of PDE5 inhibitors.

Aim

To evaluate treatment patterns using real-world data for patients initiating erectile dysfunction (ED) therapy with Viagra® (sildenafil citrate), Levitra® (vardenafil), or Cialis® (tadalafil).

Methods

Patients with an initial prescription claim for sildenafil, vardenafil, or tadalafil were identified in NDCHealth's Intelligent Health Repository. Medication refills, medication switching, and dose titration were analyzed. Logistic regression on the odds of refilling initial PDE5 medications was conducted controlling for patient age, presence of common comorbidities, initial number of tablets, and copay.

Results

A higher percentage of patients receiving sildenafil (52%) refilled their ED medication during the study period than patients receiving vardenafil (30%) or tadalafil (29%) (P < 0.001). A smaller percentage of patients in the sildenafil cohort (6.4%) switched medication than in the tadalafil (9.0%) or vardenafil (10.4%) cohorts (P < 0.001); the difference between the tadalafil and vardenafil cohorts in switching medications was also significant (P < 0.001). There were no statistically significant differences between cohorts in dose titration frequency, which was low in all three treatment cohorts. Using logistic regression, the odds of refilling initial PDE5 therapy was significantly lower for vardenafil (odds ratio [OR]: 0.39, 95% confidence interval [CI]: 0.38–0.40; P < 0.0001) and tadalafil (OR: 0.38, 95% CI: 0.37–0.40; P < 0.0001) compared with sildenafil.

Conclusions

Patients who were initially prescribed sildenafil were significantly more likely to refill their medication and significantly less likely to switch medications during the study period compared with patients who were initially prescribed vardenafil or tadalafil. These findings may indicate greater treatment satisfaction in patients receiving sildenafil, although future prospective evaluation is required.
Telemedicine: Benefits to advanced practice nursing and the communities they serve
Authors: Reed Kirby
Published: October 2005

Purpose

To review the use of telemedicine in a variety of advanced nursing practice settings, its contribution in expanding the service and role of the nurse practitioner, and the regulatory issues of reimbursement and licensure.

Data sources

Literature review of relevant journals, research articles, case examples, and web searches.

Conclusions

Although telemedicine has been utilized for many years, it has historically been used primarily by physicians. In recent years, telemedicine has been demonstrating its growing potential in advanced nursing practice in terms of economy, efficacy, and quality of care. When used appropriately, telemedicine complements advanced nursing practice in cost‐effective ways and improves healthcare access to the populations served.

Implications for practice

Incorporating telemedicine into the advanced nursing practice can be rewarding for both clinicians and their patients. Because of the high variability that exists among state regulations and payer reimbursements, clinicians are advised to verify their respective Board of Nursing Examiners, State, and payers’ policies prior to investing in the establishment of telemedicine in practice.
Complex tones with log-spaced partials
Authors: Cohen E. A. , Schubert E. D.
Published: October 2005

The importance of ratio in the chromatic scale and in the perception of musical intervals, coupled with the evidence that the cochlear transmission line exhibits logarithmic frequency spacing suggests that logarithmically spaced partials could produce exciting new musical materials. Tones with log-spaced partials were generated such that the complex tone has the same number of partials per octave as the regular harmonic series. Partial structure is of the form f1 = 2(n+m/2n)f1, with n = octave above f1 (=0, 1, 2 …); m = 0, 1, 2 … 2n − 1. In such log-spaced tones, all neighboring partials within any octave above the fundamental have the same frequency ratio. Since tones with log-spaced partials do not time lock readily, having no least common divisor, it should be difficult to separate the voices in multipart composition compared to chords composed of conventional tones. Subjects were required to identify standard intervals and were tested on hearing separate voices of simple musical phrases.
Parameters of spectral shape in speech intelligibility enhancement
Authors: Trinder J. R. , Foster J. R. , Glynn C. , Haggard M. P.
Published: October 2005

A large part of the speech intelligibility decrement in both noisy environments and in sensory hearing impairment is linked to masking, particularly of high frequencies by low, which increases as the noise or impairment becomes more severe. Considerable interest therefore attaches to optimizing intelligibility by high frequency preemphasis specific to a particular distortion. Four interrelated considerations must govern any optimization: the proximity of short term spectral peaks to discomfort level for the speech material used; the effects of gross spectral slope as such; local steepness of slope; and the (traditionally stressed) signal-to-noise ratios across the spectrum. An intelligibility enhancement experiment was conducted with normal-hearing listeners for a speech identification test presented with a noise spectrum giving masked pure tone thresholds equivalent to average hearing impaired thresholds. The conditions dissociated three of the above determinants of optimum preemphasis by using a family of filter characteristics implemented on a real-time hardware finite impulse response filter designed by the first author. With overall S/N ratio and gross spectral slope fixed, local variations in spectral slope gave only a minor degradation of intelligibility. Distinctly dichotic presentation has previously been shown not to be advantageous, but differential preemphasis may be advantageous in certain applications as it dissociates gross spectral slope from S/N ratios.
Laryngeal adjustments in the production of voiceless unaspirated, aspirated, and glottalized stops
Authors: Dent L. , Niimi S. , Lisker L.
Published: October 2005

Two talkers produced utterances that contained one of three classes of voiceless stops (unaspirated, aspirated, and glottalized stops), and simultaneous electromyographic recordings were obtained from three intrinsic laryngeal muscles (interarytenoid, lateral cricoarytenoid, and vocalis). During the production of unaspirated and aspirated stops, the interarytenoid and vocalis act in concert, inactive for the voiceless closure interval and active for voice onset following stop release. Both are markedly suppressed during closure for aspirated stops, and their activity rises (sharply in the case of the interarytenoid) for subsequent voice onset. The lateralis is uniformly inactive throughout closure and release of these two categories. By contrast, it is lateralis and vocalis that act in parallel for ejectives: a marked peak occurs in lateralis and vocalis activity during the voiceless closure interval, presumably for achievement of tight glottal closure. The interarytenoid is inactive during oral closure for ejectives and becomes active only as lateral cricoarytenoid and vocalis activity subsides following oral release. [Work supported in part by NINCDS and NIDR.]
Influences of the lower lip on upper-lip movement during speech
Authors: Folkins John W. , Linville Raymond N.
Published: October 2005

Relations between parameters of lower-lip movement and upper-lip movement were investigated during. bilabial opening and closing gestures. Upper- and lower-lip movements of five normal adults were transduced in the inferior-superior dimension with a strain gauge system. Visual feedback of lower-lip movement was employed to manipulate the displacement of the lower lip. Systematic modifications in upper-lip movement were observed as a function of the variation in lower-lip movement. The effects of lower-lip movement on upper-lip movement were larger when the jaw was fixed with a bite block. The temporal relations between lips were maintained at all lower-lip displacements both with and without the bite block. These data will be discussed relative to acoustical, mechanical, and motor control factors that may influence the interactions between lips. [Work supported by NIH.]
Individual variations in the nasal tissue vibration during speech
Authors: Horii Yoshiyuki , Lang Joan
Published: October 2005

Individual differences in the magnitude of nasal tissue vibration during sustained production of /i, a, u, m, n/ and oral reading of the “Zoo” passage (Fletcher, 1971) and “Rainbow” passage (Fairbanks, 1960) were examined using a miniature accelerometer and computerized analysis procedures. Results from eight male and eight female adults showed overall differences as large as 15 dB among the subjects. Average differences between the two passages biased with the frequency of nasal consonant occurrences ranged approximately from 6 to 10 dB. Furthermore, the relation between the nasal accelerometric level and vocal intensity level was found nonlinear and more complicated than the two-to-one power ratio reported by Garber and Moller (1979). Implications of these findings and some normalization methods (Stevens et al., 1976; Horii, 1980) are discussed. [Work supported by NIH.]
A reinterpretation of the effects of DAF on articulation
Authors: Zimmermann Gerald , Forrest Karen , Kelso J. A. Scott
Published: October 2005

The effects of delayed auditory feedback as a function of the point in the articulatory cycle at which feedback occurs was analyzed. Six subjects were exposed to two delay conditions (100 and 200 ms) and a control (no delay) condition while reading an experimental passage. Strain gauges were used to monitor lower lip and jaw movements. Preliminary analyses suggest that the specific effects of DAF (increased voice duration, increased syllable duration, movement plateaus, increased durations of movements, etc.) are related to the point in the articulatory cycle that feedback occurs. The differences in the effects of 100 and 200 ms delays may be accounted for by the probabilities that feedback will occur during different points of articulatory movement under these different delays. The DAF effect will be discussed in terms of a model of the role of auditory information in speech production rather than in terms of auditory loop times.
Notes on acoustic emission source identification
Authors: Hart S. D.
Published: October 2005

Sources of acoustic emission are often identified in the laboratory through otherwise known mechanical and material properties of the specimens. It is tempting to speculate on the possibility of identification through analysis of the signals (emissions) directly. One approach involves study of the Fourier spectra of the emissions. Recognizing that a signal must undergo any number of transformations in its passage from source to analyzer workers have sought standard or known sources which may be used to obtain the various transform functions involved through a deconvolution process. This paper will describe two proposed standard signals and results of some experiments designed to evaluate them.
In-flight crack detection via acoustic emission
Authors: Carlyle J. M.
Published: October 2005

Ultrasonic waves created by the growth of cracks are termed acoustic emissions. Triangulation techniques can be used to locate the sources of the crack emissions, but benign acoustic noise sources such as fretting bolts and chaffing plates often produce signals which are similar to crack emission signals and which hinder the positive confirmation of crack existence. A current research program is utilizing pattern recognition to distinguish between genuine crack signals and benign structural noises in an effort to develop a flyable acoustic emission integrity monitoring system. The history of the project and recent progress will be reviewed.
On-line weld monitoring with acoustic emission
Authors: Lichodziejewski W.
Published: October 2005

Detection of flaws during the welding process rather than after has many attractive features: reduction in the amount of bad weld, less costly weld repair, less repair disturbance of the welded material, etc. GARD's use of acoustic emission for flaw detection during welding (i.e., listening to acoustic signatures of flaws formed during weld solidification) has progressed significantly during the last few years —from initial attempts at simple detection of flaw presence to microprocessor-based equipment providing on-line flaw detection, flaw location, and flaw characterization (as to type and size). Interest in the technique has become prevalent enough that it is documented in a new ASTM Recommended Practice (E 749–80). This paper reviews some of the considerations in the use of the technique, presents some of the results achieved, describes some of the latest equipment developed and some of the current applications being studied.
Sound absorption in N2−H2O gas mixtures at elevated temperatures
Authors: Zuckerwar Allan J. , Meredith Roger W.
Published: October 2005

Sound absorption measurements were conducted in N2−H2O gas mixtures at 297°, 343°, and 387°K to determine the location of the vibrational relaxation peak of N2 on the frequency/pressure (f/P) axis as a function of humidity and temperature. At low humidities, the best fit of the reported data to a linear relationship between (f/P)max and humidity h yields, within experimental error, the same slope (2.00 × 104 Hz/atm mole fraction) at all three temperatures. The slope is lower than the value of 2.6 × 104 reported by Chang, Shields, and Bass at higher humidities [J. Acoust. Soc. Am. 63, 577–581 (1977)], but the two sets of data are shown to be mutually consistent by means of a model in which V-V transfer is assumed to provide the dominant relaxation path. The relationship between (f/P)max and h written into ANSI Standard S1.26/ASA23-1978 contains an excessively large slope, does not account for the observed transition between the low-humidity and high-humidity slopes, and specifies an erroneous temperature dependence. [Work supported by NASA Grant NSG 1324.]
The effects of spectral fusion on the perception of pitch for complex tones
Authors: Mc Adams Stephen
Published: October 2005

Pitch can be shown to be a perceptual attribute that is built up from the internal representation of an actual or virtual “source” rather than being derived directly from the waveform. Michael Mc Nabb and John Chowning at CCRMA, Stanford University, have developed a technique whereby several sine wave components can be made to fuse into a unitary percept by introducing parallel vibrato (combined random and periodic frequency modulation at subaudio frequencies) to all spectral components. If different subsets of components in a spectral complex are subjected to different vibrato patterns, they separately fuse into virtual sources, each with their respective pitch. Spectral fusion depends on the harmonicity and recognizability of the spectral subset, e.g., whether it resembles a voice, trumpet, etc. And the separation of subsets depends, in part, on the correlation of their vibrate functions. With inharmonic spectra, pitch changes can be made to occur by causing different parsings of the spectrum into sources. This strongly suggests that pitch is a property assigned to a source after a certain amount of perceptual and cognitive processing of the time-arying spectrum has taken place. Further, the fact that pitch depends on context, i.e., depends on the determination of the source on the basis of spectral congruity, necessitates a re-evaluation of the methodology of pitch research.
Identification of stops and vowels in truncated CV syllables
Authors: Pisoni David B. , Kewley-Port Diane
Published: October 2005

How is the information specifying place of articulation and vowel color encoded in a stop-vowel syllable? Are place cues located in just the burst, or the first 20 ms of a CV waveform as some investigators have suggested? Alternatively, are place cues encoded simultaneously (i.e., in parallel) with vowel information in the formant transitions? To answer these questions, an identification experiment was conducted using the consonants /b, d, g/ paired with the vowels /i, e, a, o, u/ produced by two male talkers. Using computer techniques, five truncated stops were edited from each original syllable. Cuts were made after the release burst, and then the burst plus 1, 3, 5, or 7 pitch pulses. On different days, naive subjects identified either the consonant or the vowel. Identification functions for /b/ and /d/ reached 95% correct within the first 20 ms. Vowels, except for /i/, were identified near chance for the shortest stimuli. The consonant /g/ needed a longer duration, 40 to 50 ms, for correct place identification, although /gi/ was never identified accurately even at the longest durations. We conclude that sufficient acoustic information for identifying the stops /b/ and /d/ can be found within the first 20 ms of a CV syllable, although information for the /g/ extends over somewhat longer durations. Formant transitions appear to carry information about the vowel although somewhat less information about the consonant, except for /g/ before front vowels. [Supported by NINCDS Grant NS-12179.]
More adaptation of speech and nonspeech
Authors: Kat Donna , Samuel Arthur G.
Published: October 2005

In a previous study [A. G. Samuel and E. L. Newport, J. Exp. Psychol.: Hum. Perc. Perf. 5(3), 563–578 (1979)], nonspeech adaptors (440 Hz sawtooth waves and white noise segments, with 0- or 80-ms rise times) caused significant labeling shifts on speech continua. In particular, the abruptly onsetting sawtooth reduced the number of [ba]'s reported (versus [wa]), and the gradually onsetting noise segment reduced responses of [sha] (versus [cha]. These results suggested that (1) speech and nonspeech are processed by the same mechanisms, and (2) these mechanisms are sensitive to the general spectral quality of the input, i.e. whether the spectrum is generally flat (aperiodic) or peaked (periodic). In the present study, the same four adaptors were used on a [dɜɑ]—[ɜɑ] continuum. These stimuli have spectra quite similar to [+∫ɑ]—[∫ɑ], but are voiced, and thus have a low-frequency periodic component. As with [cha]—[sha], only the gradually onsetting noise adaptor was effective. These results indicate that as suggested in the earlier study, overall spectral quality (“flat” versus “peaked”) is the critical determinant, not the presence or absence of glottal pulsing.
Evaluation of a spectrographic display as a speech training aid for the deaf
Authors: Houde Robert A.
Published: October 2005

A general anaysis of speech training for the deaf was carried out to identify those functions which might be served by a speech display. The primary role of a speech display was identified as that of providing the student with the means of practicing independently. A procedure was developed by which deaf students received a significant portion of their individual speech training through independent work with a real-time speech spectrographic display. The progress of children (ages 6–13) trained by independent work with the spectrographic display was compared to that of children trained by teachers within the same procedure. The principal results were: (1) the effectiveness of training by visual display was equal to that of training by teachers; (2) all of the children, including the very youngest were able to work effectively and independently with the spectrographic display.
Structural vibrations in an acoustic medium: An amateur teacher's experience
Authors: Junger M. C.
Published: October 2005

This speaker describes the experience of a consultant and researcher who spent ten years teaching this subject to mechanical, civil, and ocean engineers largely unfamiliar with acoustics. It is indicative of this gap that the acoustics branch germane to structural vibrations was founded by fluid mechanicists (Stokes, Lamb) rather than structural mechanicists. A central concept acceptable to the vibrations engineer models the fluid as a distributed load formulated in terms of an impedance. A second essential concept is that this load's nature (masslike reactance in the hydrodynamic limiting case, or resistance when fluid compressibility predominates) is determined by one dimensionless number: The ratio of acoustic to structural wavenumber. Radiation loading is finally formulated as generalized forces proportional to the structure's modal response or as a distributed load proportional to the wavenumber transform of the structural response.
Theoretical acoustics at the doctoral level
Authors: Eisler J.
Published: October 2005

A course on the radiation and scattering of acoustic waves is described as taught at the Catholic University. It is intended to serve as a foundation for other doctoral level courses with emphasis and critical scrutiny of the basic principles of acoustics. A further purpose is to introduce the mathematical methods used in theoretical acoustics with an appropriate degree of rigor. By restricting boundary conditions to idealized cases, reasonable coverage may be given both to the mathematical toolbox and to the important theories of the low and high frequency regimes. Thus the student is prepared for a critical understanding of technical problems at the research level.
Variational principles for fluid-solid interactions, with application to ship beams
Authors: Sarigül N. , Bökmeci M. C.
Published: October 2005

The purpose of this paper is threefold: (1) To derive the unconstrained variational principles which treat initial and boundary value problems of fluid-solid interactions in a unified manner, then by using it (2) to establish the one-dimensional governing equations of vibrations of ship beams immersed in an ideal fluid, and also (3) to examine the uniqueness in solutions of these equations. First, a general principle of physics (Hamilton's principle) is transformed so as to derive the variational principles through the dislocation potentials and Lagrange multipliers. Next, the variational principles together with the generalized Mindlin method of structures are used to construct the governing equations by expanding the displacement components and the hydrodynamic pressure in series. The governing equations are coupled with the pressure field and incorporate all the effects of transverse shear and normal strains and the rotatory inertia, and they accommodate all the types of extensional, flexural, and torsional motions of ship beams. Also, the uniqueness is examined, and the sufficient conditions are enumerated for it. [Work supported by TÜBİTAK.]
Ensemble averages of power flow in randomly excited coupled beams
Authors: Davies H. G. , Wahab M. A.
Published: October 2005

This paper considers the transmission of transverse vibrational energy between two coupled beams subjected to random excitation. Extensive numerical results are given for the frequency decomposition of power flow between the beams. The power flow is a function of the three nondimensional parameters describing frequency, w/w1, where w1 is the fundamental resonance frequency of beam one, length ratio, L2/L1, and damping or modal overlap ratio. Single frequency and octave band averages are shown for various values of L2/L1, and means and variances are calculated for the ensemble of systems corresponding to a uniform distribution of 1 ⩽ L2/L1 ⩽ 2. Various approximate results based on modal analysis and on SEA are compared with the exact results.
Energy transmission into shadow zone by rough surface boundary wave
Authors: Tolstoy Ivan
Published: October 2005

Biot-type rough surface boundary conditions predict the existence of a subsonic boundary wave. For a stratified fluid with sound velocity decreasing away from the surface, i.e., under shadow zone conditions, it can be shown that, for point source and receiver near this surface, the farfield of the boundary wave behaves like bor-1/2 exp(ikr − aor). The attenuation coefficient is, in the present approximation, due to a tunneling effect. The standard acoustic (volume) wave diffracted field is, under the same conditions, a sum of terms bmr-1/2 exp(ikr − amr). Calculation shows that, for many cases of interest in underwater acoustics, a0 ≪ a1where a1 corresponds to the least attenuated of the diffracted modes. The wall roughness boundary wave then transmits substantially more energy into the shadow zone than is allowed for by ordinary diffraction effects. [Work supported by ONR.]
Equivalence between 4th sound in liquid He II and the Biot slow wave in consolidated porous media
Authors: Johnson David Linton
Published: October 2005

The theory of acoustic propagation in porous fluid-filled media due to M. A. Biot is applied to the case where superfluid 4He is in the pores (T < 1.1°K). For a consolidated (fused) matrix Biot's slow compressional wave is shown to be identical to the phenomenon known as 4th sound; Rudnick's index of refraction is derived from the Biot theory. Predictions for the velocities of the fast wave, the shear wave, and the slow wave/4th sound are made for fused glass bead samples in which Plona has previously reported seeing these three waves under the condition of water saturation. These predictions for the fused glass beads are made for temperatures less than ∼ 1.1°K, where there is a negligible amount of normal He fluid.
Spatial dispersion in porous elastic media
Authors: Devaney A. J.
Published: October 2005

It is shown that according to Biot's theory, the average displacement vector in a homogeneous, isotropic porous medium propagates as though it were in a homogeneous, isotropic elastic solid whose constitutive relation (Hooke's Law) is nonlocal in both space and time. Spatially nonlocal constitutive relations are well-known in electromagnetics and systems exhibiting such behavior have been called spatially dispersive [G. S. Agarwal, D. N. Pattanayak, and E. Wolf, Phys. Rev. B10, 1447 (1974)]. Spatial dispersion in elastic systems shares many similarities to spatial dispersion in electromagnetics including the possible occurrence of a multiplicity of roots in the dispersion relation. For porous media, this multiplicity of roots causes the system to possess more than one compressional wave velocity which, in turn, introduces problems when solving for reflection and transmission coefficients from bounded porous media [J. Geertsma and D.C. Smit, Geophysics 26, 169 (1961), J. H. Rosenbaum, Geophysics 39, 13 (1974)]. One procedure for calculating these coefficients for spatially dispersive electromagnetic systems has been found to yield good agreement with experimental results and (its elastodynamic generalization) is suggested for use in the porous medium case.
A comparison of atmospheric acoustic sounder configurations versus meteorological conditions
Authors: Peterman K. Russell
Published: October 2005

The relationship of atmospheric data gathered from three-axis bistatic sounders operating at 1, 2, and 4 kHz, and a 2-kHz three-axis monostatic sounder is presented. Wind profiles are computed using the complex covariance function of the returned signal to estimate the power spectrum mean frequency. The backscatter data are presented as high quality grey scale and pseudocolor temperature structure. The data were gathered over varied terrain from Texas to Alaska and represent a sample of common and unique planetary boundary layer events including: ground radiation inversions; elevated subsidence inversions showing shear and convection stresses; gravity wave trains; and convection cells correlated with vertical winds. Several unique events are presented including an isolated large amplitude gravity wave (>600 m) associated with a frontal passage and a radiation inversion with an associated low level jet producing extreme low level shear (≈12 m s-1/150 m). The computational techniques and the associated geometry and frequency are compared to a previously published overview [E. H. Brown and F. H. Hall, Jr., Rev. Geophys. Space Phys. 16, (1) 47–110].
A reversal of lateralization, with images appearing on the side of the delay
Authors: Hafter Ervin R. , Shelton Brian R. , Green David M.
Published: October 2005

Unlike the case with tones, where sensitivity to interaural delay exists only for low frequencies, delays in the envelopes of amplitude modulated sounds are effective, regardless of the frequency of the carrier. Interestingly, for pulse-modulation of band-limited noise, the percept caused by interaural delay can be quite misleading, with the image appearing on the side of the lagging signal [Hafter and Ricard, J. Acoust. Soc. Am. 53, 335(A) (1973)]. This anomaly depends upon the frequency of the carder, with the image being on the “correct” side for low frequencies and then exhibiting a damped oscillation around the midline as the carrier is increased. A simple model which fits the data well associates the location of the image with the center of gravity (CG) of the cross-correlation function, computed from the acoustic waveforms with the signs of the correlation maintained in the computation. In this way, negative peaks in the function act to repel the CG just as positive peaks act to attract it. For localization in the free field, where interaural differences of phase are the result of pure delay, the cross-correlation function is symmetric and signed negative peaks do not affect the CG. It is only when the functions are asymmetric, as with envelope delay, that the reversal effect appears.
Intelligibility of consonants produced by dyadic rule synthesis
Authors: Olive Joseph P. , O'Connor-Dukes Kathleen , Liberman Mark Y.
Published: October 2005

In a previous experiment, J. Olive and L. Pols [J. Acoust. Soc. Am. Suppl. 1 66, S23 (1979)] reported on the intelligibility of speech generated by dyadic rule synthesis. Their analyses showed that significant improvements in intelligibility could be gained from a more optimal choice of the method of choosing both the dyads and the parameters of the dyads themselves. The present paper describes a quantitative method for choosing better dyads and results from an experiment using the improved dyad set. We measured the intelligibility of initial and final consonants in CVC words, using 11 different vowels. Two other conditions were tested for comparison; PCM-coded speech (12 bits, 10-kHz rate) and LPC-resynthesized speech (12 parameters).
Masking level difference: Evidence for contribution of superior olivary complex
Authors: Hannley Maureen , Jerger James
Published: October 2005

The masking level difference (MLD) for a 500-Hz tone in broad band noise, and the auditory brain stem response (ABR) were compared in 20 patients with multiple sclerosis. Abnormality in ABR, especially delay or absence of the Jewett wave III, was related to reduction in MLD. These results support the view that the superior olivary complex plays a major role in mediating the MLD effect.
Aerodynamic impact sound from colliding spheres for calibration of microphone systems
Authors: Nedzelnitsky Victor , Tarica Mitchell
Published: October 2005

Tentative damage-risk criteria for hearing and material design standards require measuring the peak values of impulsive sounds. However, use of current or proposed ANSI and IEC standards provides only the magnitude calibration in response to sinusoids, and does not ensure accuracy in measuring the peak values of impulsive sounds. We have used digital transient capture and FFT techniques with a 3.2-mm-diam microphone system calibrated in magnitude and phase to measure peak sound pressure levels and spectra of impact sounds produced by a prototype source. This source uses an essentially identical pair of colliding steel spheres of either 25.4- or 44.5-mm diameter to produce peak sound pressure levels within the range 100-120 dB re 0.00002 Pa with precisions (ranges of peak amplitudes of nominally identical impacts) of 0.5 dB or better, and with spectra exhibiting fairly broad maxima within the range 3-10 kHz. For some conditions, at least, the waveform of sound pressure is approximately diphasic, and of duration <0.5 ms. The results demonstrate the feasibility of a simple, robust sound source suitable for use in moderately noisy, nonanechoic environments to check the free-field response of microphone systems, and subsequent instrumentation, to impulsive sounds.
Use of glass fiber materials in industrial and commercial buildings
Authors: Harris David A.
Published: October 2005

Many types of glass fiber products, composites, and systems can be effectively employed to reduce excessive noise levels in industrial and commercial buildings. New and expanded acoustical data are presented on the best utilization of glass fiber materials in ceilings, interior and exterior walls or roofs, air distribution systems, pipe quieting, source and receiver enclosures, and related acoustical treatments.
Modern analysis procedures for multiple input/output problems
Authors: Bendat J. S.
Published: October 2005

Modern analysis procedures for solving multiple input/output problems are not only more efficient than older techniques but also provide greater engineering insight into the physical meaning of various relationships. Applications include identification of system properties and response effects, estimation of time delays and propagation velocities, determination of energy sources, and utilization of practical statistical error formulas to evaluate results. This lecture will review some of these matters to explain basic concepts on how to obtain conditioned spectral density functions, partial and multiple coherence functions to analyze random vibration and noise data representing multiple random records, where arbitrary correlations can exist among the records.
An application of coherence functions for evaluating dynamic excitation sources
Authors: Barrett S.
Published: October 2005

The feasibility of using coherence functions to evaluate the relative contributions of multiple dynamic inputs to the vibration environment of a spacecraft component was examined. Data for the study were generated by applying simultaneous vibratory and acoustic random inputs to a realistic test model consisting of an instrumentation truss from a Titan launch vehicle, with a lightly loaded panel added to provide response data. Both independent and correlated inputs were used. A digital computer program was written to analyze the test data, using a mathematical approach based on iterative computational algorithms developed by Bendat. This approach is simpler than earlier matrix methods and is thought to be more economical in terms of computer time. It was found that the coherence function technique was effective in evaluating sources of excitation, for both correlated and noncorrelated cases. To calculate coherence functions with high accuracy, it is necessary to use smoothed estimates of the associated auto and cross spectra. The effect of varying the number of data samples used in the smoothing process was briefly investigated. [Work performed under NASA Contract NASI-14370.]
Application of multiple input/output analysis techniques to industrial acoustic & vibrational problems
Authors: Wu P. T.
Published: October 2005

Multiple input/output analysis techniques are reviewed. Applications of these techniques to two acoustic and vibrational problems were suggested. The first application is for elimination of extraneous noise for in situ sound power measurement. The second application is for locating a structural vibration source within a complex mechanical system in a noisy environment. Field data for both cases are presented to illustrate the result.
Decay of sound in an enclosure with diffusely reflecting boundary
Authors: Miles R. N. , Carroll M. M.
Published: October 2005

An integral equation is derived which describes the decay of sound in an enclosure which has diffusely reflecting and non-uniformly absorbent walls. The expression is obtained by constructing the Laplace transform of the time varying sound intensity at each point on the enclosures surface. It is found that after a sufficient time has elapsed after the sound source is removed, the surface intensity and the sound energy density decay exponentially and the rate of decay depends on the distribution of the absorbent material. Numerical solutions are presented for a right rectangular parallelepiped with nonuniform absorption on the walls.
Performance of hemi-anechoic Rooms
Authors: Moreland J. B.
Published: October 2005

Because the constructive and destructive interference between a source and its image formed by the ground plane obscures the conformity of the sound field with the inverse square law, we have used a carousel method to evaluate the performance of hemi-anechoic rooms (i.e., free field rooms with acoustically hard floors). Using the carousel method, the spatial variation of the SPL in hemi-anechoic rooms having the overall shape of a rectangular parallelepiped periodically fluctuates around a mean value. The amplitude of these spatial fluctuations is a function of the room wall acoustic properties and decreases as the carousel radius decreases and as the frequency and bandwidth increases. We take the rms value of these spatial fluctuations as a measure of the room performance. We conclude that the performance of hemi-anechoic rooms having thick, fibrous glass blankets on the walls and ceiling compares favorably with anechoic rooms having wedge-lined walls and ceiling. Furthermore, since the walls and ceiling of rooms having fibrous glass blankets can be represented by a partially absorbing plane of known surface impedance, the performance of such rooms can be predicted.
The effect of a deep niche on the laboratory measured sound transmission loss
Authors: Gilbert John C.
Published: October 2005

Round robin measurements in acoustical laboratories have shown that laboratory design plays a significant role in the determination of the sound transmission loss (TL). An important factor affecting the TL is the occurrence of a so-called “deep niche.” A niche occurs when the depth of the test opening is greater than the thickness of the object under test. Mounting a specimen at one end of the test opening creates a niche which is formed by the test opening surfaces and the panel surface itself. Mounting the panel in the center of the test opening creates equal niches on each side of the panel, etc. The effect of the panel location in the test opening on the transmission loss as well as the effect of overall test opening length was studied. Under some conditions, differences as great as 8 dB were observed. Effects occurred only at frequencies below the coincidence frequency. Variation in the transmission loss as a function of position in the test opening was less for deep niches than for short niches.