bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of continuous glucose monitoring to introduce adjunctive pramlintide therapy in a patient with type 1 diabetes: A case study
Authors: Walker Tomas C.
Published: July 2011

Purpose: To report the successful use of a continuous glucose monitoring system (CGMS) in helping a patient with type 1 diabetes initiate a new diabetes therapy, pramlintide, which improves glycemic control.

Data sources: Case report, diagnostic evidence, and scientific literature.

Conclusions: CGMS data before and 3 months after pramlintide initiation supported the changes felt by the patient. Diurnal and postprandial glucose excursions decreased with a resultant decrease in A1C from 9% to 7.4%. Additionally, body weight decreased by 8 lbs and hypoglycemic events declined markedly. No nocturnal hypoglycemic events occurred during the observation period.

Implications for practice: Given the serious and chronic nature of diabetes, it is paramount for the patient and healthcare provider to develop and modify as needed treatment regimens that help the patient achieve and maintain glycemic control over time—a difficult task even in the motivated patient. In patients with type 1 diabetes, pramlintide can further improve glycemic control and CGMS can be a beneficial tool for monitoring that change.
Sensitivity of oral fluids for detecting influenza A virus in populations of vaccinated and non‐vaccinated pigs
Authors: Romagosa Anna , Gramer Marie , Joo Han Soo , Torremorell Montserrat
Published: July 2011

Please cite this paper as: Romagosa et al. (2011) Sensitivity of oral fluids for detecting influenza A virus in populations of vaccinated and non‐vaccinated pigs. Influenza and Other Respiratory Viruses.

Background/objective  We evaluated the sensitivity of PCR on oral fluids in detecting influenza virus in vaccinated and non‐vaccinated pigs.

Methods  Three‐week‐old influenza‐free pigs were divided into three groups: (i) control, non‐vaccinated, (ii) vaccinated with a commercial, heterologous vaccine, and (iii) vaccinated with an experimental, homologous vaccine. After vaccination, an influenza‐infected pig was placed in contact with each of the groups. Individual nasal swabs and pen oral fluids were collected daily. Viral RNA was tested for the presence of influenza by RRT‐PCR and virus isolation attempted from oral fluids. A pen was considered positive if at least one nasal swab was positive.

Results  Based on nasal swab results, 43·8% of pens were detected positive but only 35% based on oral fluids. Overall sensitivity of oral fluids was 80%, and virus was isolated from 51% of RRT‐PCR‐positive oral fluids. The kappa coefficient for agreement (ĸ) between oral fluids and nasal swabs was 0·82. Among groups, ĸ was 1 (95% CI, 1–1), 0·74 (95% CI, 0·55–0·92), and 0·76 (95% CI, 0·5–1) for control, heterologous, and homologous‐vaccinated groups, respectively. There was less agreement when within pen prevalence was 10% or less. Probability of detecting influenza virus in oral fluids was 99% when within pen prevalence was higher than 18% and decreased to 69% when prevalence was 9%.

Conclusions  Results indicated that pen‐based collection of oral fluids is a sensitive method to detect influenza even when within pen prevalence is low and when pigs have been vaccinated and highlight the potential use of oral fluids for influenza surveillance.
The effect of giving intra‐operative local anaesthetic (lidocaine 2% with 1:80 000 adrenaline) on post‐operative pain in adolescents having day‐case oral surgery to facilitate orthodontic treatment: A blinded, randomised controlled trial
Authors: Murphy M.
Published: July 2011

Aim:  To elucidate the effect of giving local anaesthetic to adolescents having oral surgery carried out under day‐case general anaesthetic on their post‐operative pain.

Materials and methods:  Randomised, blinded, placebo‐controlled design. Sixty‐eight subjects aged 12–16 years randomly assigned to receive either a local anaesthetic (2% lidocaine with 1:80 000 adrenaline) or placebo (saline) infiltration at the surgical site before the start of surgery. Pain assessed by a research nurse using a visual analogue scale, firstly pre‐surgery and then at 30, 60 and 120 min post‐surgery. The time of post‐surgery rescue analgesia requirements also noted.

Results:  Mean pain scores were significantly less in the local anaesthetic group compared with the placebo group at 30 min post‐surgery (P < 0.01) and at 60 min post‐surgery (P < 0.01). There was no significant difference in mean pain scores at 120 min at which time the mean pain score in the placebo group had reduced to approach that of the local anaesthetic group. More subjects in the placebo group (21) required rescue analgesia compared with the local anaesthetic group (12). The mean time to rescue analgesia was significantly longer in the local anaesthetic group compared with the placebo group (P = 0.04).

Conclusions:  Giving local anaesthetic infiltrations at the surgical site significantly reduced post‐operative pain in the early stages following oral surgery procedures carried out under general anaesthesia in adolescent subjects. It also reduced the need for post‐surgery analgesia and significantly increased the time from surgery to any such required analgesia.
Leibniz on the Metaphysics of Color
Authors: Puryear Stephen
Published: July 2011

Drawing on remarks scattered through his writings, I argue that Leibniz has a highly distinctive and interesting theory of color. The central feature of the theory is the way in which it combines a nuanced subjectivism about color with a reductive approach of a sort usually associated with objectivist theories of color. After reconstructing Leibniz's theory and calling attention to some of its most notable attractions, I turn to the apparent incompatibility of its subjective and reductive components. I argue that this apparent tension vanishes in light of his rejection of a widely accepted doctrine concerning the nature of bodies and their geometrical qualities.
Ritz Legendre Multiwavelet Method for the Damped Generalized Regularized Long-Wave Equation
Authors: Yousefi S. A. , Barikbin Z.
Published: July 2011

In this paper, a numerical method is proposed to approximate the solution of the nonlinear damped generalized regularized long-wave (DGRLW) equation with a variable coefficient. The method is based upon Ritz Legendre multiwavelet approximations. The properties of Legendre multiwavelet are first presented. These properties together with the Galerkin method are then utilized to reduce the nonlinear DGRLW equation to the solution of algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the technique.
Use of the Non-Inertial Coordinates in the Analysis of Train Longitudinal Forces
Authors: Shabana Ahmed A. , Aboubakr Ahmed K. , Ding Lifen
Published: July 2011

In this investigation, a new three-dimensional nonlinear train car coupler model that takes into account the geometric nonlinearity due to the coupler and car body displacements is developed. The proposed nonlinear coupler model allows for arbitrary three-dimensional motion of the car bodies and captures kinematic degrees of freedom that are not captured using existing simpler models. The coupler kinematic equations are expressed in terms of the car body coordinates, as well as the relative coordinates of the coupler with respect to the car body. The virtual work is used to obtain expressions for the generalized forces associated with the car body and coupler coordinates. By assuming the inertia of the coupler components negligible compared to the inertia of the car body, the system coordinates are partitioned into two distinct sets: inertial and noninertial coordinates. The inertial coordinates that describe the car motion have inertia forces associated with them. The noninertial coupler coordinates; on the other hand, describe the coupler kinematics and have no inertia forces associated with them. The use of the principle of virtual work leads to a coupled system of differential and algebraic equations expressed in terms of the inertial and noninertial coordinates. The differential equations, which depend on the coupler noninertial coordinates, govern the motion of the train cars; whereas the algebraic force equations are the result of the quasi-static equilibrium conditions of the massless coupler components. Given the inertial coordinates and velocities, the quasi-static coupler algebraic force equations are solved iteratively for the noninertial coordinates using a Newton–Raphson algorithm. This approach leads to significant reduction in the numbers of state equations, system inertial coordinates, and constraint equations; and allows avoiding a system of stiff differential equations that can arise because of the relatively small coupler mass. The use of the concept of the noninertial coordinates and the resulting differential/algebraic equations obtained in this study is demonstrated using the knuckle coupler, which is widely used in North America. Numerical results of simple train models are presented in order to demonstrate the use of the formulation developed in this paper.
Control of a Forced Impacting Hertzian Contact Oscillator Near Sub- and Superharmonic Resonances of Order 2
Authors: Bichri Amine , Belhaq Mohamed
Published: July 2011

The effect of a fast harmonic base displacement and of a fast periodically time varying stiffness on vibroimpact dynamics of a forced single-sided Hertzian contact oscillator is investigated analytically and numerically near sub- and superharmonic resonances of order 2. The study is carried out using averaging procedure over the fast dynamic and applying a perturbation analysis on the slow dynamic. The results show that a fast harmonic base displacement shifts the location of jumps, triggering the vibroimpact response, toward lower frequencies, while a fast periodically time-varying stiffness shifts the jumps toward higher frequencies. This result has been confirmed numerically for both sub- and superharmonic resonances of order 2. It is also demonstrated that the shift toward higher frequencies produced by a fast harmonic parametric stiffness is larger than that induced by a fast base displacement.
Aerodynamic Measurements on a Vertical Axis Wind Turbine in a Large Scale Wind Tunnel
Authors: Battisti L. , Zanne L. , Dell’Anna S. , Dossena V. , Persico G. , Paradiso B.
Published: July 2011

This paper presents the first results of a wide experimental investigation on the aerodynamics of a vertical axis wind turbine. Vertical axis wind turbines have recently received particular attention, as interesting alternative for small and micro generation applications. However, the complex fluid dynamic mechanisms occurring in these machines make the aerodynamic optimization of the rotors still an open issue and detailed experimental analyses are now highly recommended to convert improved flow field comprehensions into novel design techniques. The experiments were performed in the large-scale wind tunnel of the Politecnico di Milano (Italy), where real-scale wind turbines for micro generation can be tested in full similarity conditions. Open and closed wind tunnel configurations are considered in such a way to quantify the influence of model blockage for several operational conditions. Integral torque and thrust measurements, as well as detailed aerodynamic measurements were carried out to characterize the 3D flow field downstream of the turbine. The local unsteady flow field and the streamwise turbulent component, both resolved in phase with the rotor position, were derived by hot wire measurements. The paper critically analyses the models and the correlations usually applied to correct the wind tunnel blockage effects. Results highlight that the presently available theoretical correction models do not provide accurate estimates of the blockage effect in the case of vertical axis wind turbines. The tip aerodynamic phenomena, in particular, seem to play a key role for the prediction of the turbine performance; large-scale unsteadiness is observed in that region and a simple flow model is used here to explain the different flow features with respect to horizontal axis wind turbines.
Winglet Dihedral Effect on Flow Behavior and Aerodynamic Performance of NACA0012 Wings
Authors: Yen Shun C. , Fei Yu F.
Published: July 2011

This study investigates the effects of Reynolds number, angle of attack, and winglet dihedral (δ) on the smoke-streak flow patterns, surface oil-flow configurations, and aerodynamic performance of the wingleted wings. The airfoil is NACA 0012 and the winglet dihedral varies from −30° to 135°. The smoke-wire technique was utilized to visualize the three-dimensional flow structures. Furthermore, the effect of δ on the wingtip surface vortex was examined using the surface oil-flow scheme. The wingtip surface vortex was observed on a baseline wing using the smoke-streak flow and surface-oil flow visualization schemes. Moreover, the length of wingtip surface vortex (Lb) decreases with increasing δ for δ > 15° where Lb denotes the major axis of wingtip surface vortex. The maximum Lb/C of 1.2 occurs at δ = 15° which is about 42% higher than that of a baseline wing, where C represents the wing chord length. The high flow momentum expands the wingtip surface vortex toward the winglet when δ < 15°. However, the minimum Lb/C of 0.55 occurs at δ = 90° which is about 34% lower than that of a baseline wing because the wingtip surface vortex is squeezed intensely at high δ. The aerodynamic performance was measured using a force-moment balance. The experimental data indicates that the lift-drag ratio at stalling (CL/CD)stall and maximum lift-drag ratio (CL/CD)max occurs at δ = 90°.
On the Effects of a Flexible Structure on Boundary Layer Stability and Transition
Authors: Musleh Ashraf Al , Frendi Abdelkader
Published: July 2011

Delaying the onset of boundary layer transition has become a major research area in the last few years. This delay can be achieved by either active or passive control techniques. In the present paper, the effects of flexible or compliant structures on boundary layer stability and transition is studied. The Orr-Sommerfeld equation coupled to a beam equation representing the flexible structure is solved for a Blasius type boundary layer. A parametric study consisting of the beam thickness and material properties is carried out. In addition, the effect of fluid wall shear stress on boundary layer stability is analyzed. It is found that high density and high Young modulus materials behave like rigid structures and therefore do not alter the stability characteristic of the boundary layer. Whereas low density and low Young modulus materials are found to stabilize the boundary layer. High values of fluid wall shear stress are found to destabilize the boundary layer. Our results are in good agreement with those published in the literature.
Optimized knot placement for B‐splines in deformable image registration
Authors: Jacobson Travis J. , Murphy Martin J.
Published: July 2011

Purpose: To develop an automatic knot placement algorithm to enable the use of NonUniform Rational B‐Splines (NURBS) in deformable image registration.Methods: The authors developed a two‐step approach to fit a known displacement vector field (DVF). An initial fit was made with uniform knot spacing. The error generated by this fit was then assigned as an attractive force pulling on the knots, acting against a resistive spring force in an iterative equilibration scheme. To demonstrate the accuracy gain of knot optimization over uniform knot placement, we compared the sum of the squared errors and the frequency of large errors.Results: Fits were made to a one‐dimensional DVF using 1–20 free knots. Given the same number of free knots, the optimized, nonuniform B‐spline fit produced a smaller error than the uniform B‐spline fit. The accuracy was improved by a mean factor of 4.02. The optimized B‐spline was found to greatly reduce the number of errors more than 1 standard deviation from the mean error of the uniform fit. The uniform B‐spline had 15 such errors, while the optimized B‐spline had only two. The algorithm was extended to fit a two‐dimensional DVF using control point grid sizes ranging from 8 × 8 to 15 × 15. Compared with uniform fits, the optimized B‐spline fits were again found to reduce the sum of squared errors (mean ratio = 2.61) and number of large errors (mean ratio = 4.50).Conclusions: Nonuniform B‐splines offer an attractive alternative to uniform B‐splines in modeling the DVF. They carry forward the mathematical compactness of B‐splines while simultaneously introducing new degrees of freedom. The increased adaptability of knot placement gained from the generalization to NURBS offers increased local control as well as the ability to explicitly represent topological discontinuities.
Computational methods in architectural acoustics.
Authors: Vorländer Michael
Published: July 2011

Sound field modeling and auralization have been used in architectural acoustics for many years. Today, the technique of auralization can also be implemented with real-time performance. Then it is part of the technology of virtual reality. Apparent simple scenarios of interaction, however, for instance, when a person is leaving a room and closes a door, require complex models of room acoustics and sound transmission. Otherwise the coloration, the loudness, and timbre of sound within and between rooms are not represented adequately. Still numerous approximations must be made to reach this goal. In the end, the resulting sound is not intended to be physically correct, but perceptively plausible. Knowledge about human sound perception is, therefore, a very important prerequisite to evaluate auralized sounds. In this paper the algorithms for sound field rendering and spatial reproduction are reviewed and discussed with regard to future research.
Time series simulation of underwater sound: Key issues and techniques.
Authors: Goddard Robert P.
Published: July 2011

Computer systems for generating simulated underwater sound have been in use for more than 30 years. Such systems, including the author’s sonar simulation toolset (SST), enable users to build an artificial ocean that sounds like a real ocean, as heard by a user-specified listening system. Such signals are useful for designing new acoustic systems for undersea sensing or communication, testing existing systems, predicting performance, developing tactics, training operators, planning experiments, and interpreting measurements. Signals of interest include reverberation, target echoes, discrete sound sources, and background noise. The author will describe, in broad outline, techniques for generating simulated underwater sound and criteria for choosing among them, focusing on target echoes and reverberation for active sonar systems. The characteristics of the ocean as an acoustic medium, the characteristics of the sensors, the processing and display systems behind the sensors, the purpose of the simulation, and the computational resources available for the simulation all strongly influence the choice of algorithms to achieve useful, cost-effective, simulated underwater sound. The characteristics of the human auditory system are of minor importance.
Using auditory models to study masking due to anthropogenic sound.
Authors: Mountain David C.
Published: July 2011

The mammalian auditory system is a highly evolved acoustic signal processing system that performs well even in highly reverberant and cluttered acoustic environments. In cetaceans, the auditory system is even more highly evolved than vision and is extremely important for navigation, foraging, and social communication. As humans inject more and more acoustic energies into the marine environment, these important acoustic functions may become compromised. Unfortunately little is known about the impact of anthropogenic sounds that could mask biologically significant signals. In this study a desktop simulation environment was used to study masking effects in a variety of conditions. The acoustic scenarios were created by mixing cetacean vocalizations recorded under relatively quiet conditions with scaled recordings of shipping noise. Biophysical computer models (http://earlab.bu.edu) based on physiological and behavioral experiments performed on humans were extrapolated to represent several different cetacean species. Model parameters for species of interest were estimated from behavioral audiograms and from other available data. These models were then used to predict how different types of biologically significant sounds are represented in neural firing patterns and how the neural representation degrades in the presence of anthropogenic noise.
Oceanic shipping soundscapes.
Authors: de Moustier Christian , Porter Michael
Published: July 2011

Shipping and wind are key sources in the oceanic soundscape that affects marine mammal habitats. A new method of forming such soundscapes is presented. Frequency and range dependent transmission losses are precomputed from a grid of virtual sources using fast ray computations (BELLHOP) on a specified number of radial lines. Each radial line samples the bathymetry along its bearing out to a given maximum range. A shipping soundscape is then estimated by assigning a source spectral density level (dB re 1 μ Pa2/Hz) and a shipping density (number of ships per unit area per unit time) to the various grid nodes. Such density values are obtained directly from ships carrying an automatic identification system (AIS) that transmit information such as ship type, position, heading, and speed. They can be obtained also from compiled statistics of AIS data (e.g., number of transits per year in an area). The same gridding approach is used to predict wind-generated sound levels based on maps of average wind speeds in an area for a given epoch, or on maps of forecast wind speeds.
Application of automatic identification system information to ocean soundscape modeling.
Authors: Joseph John E. , Miller Christopher
Published: July 2011

The impact of anthropogenic noise on marine life is an important issue to both the scientific community and public policy makers. Human-generated noise has potential to disrupt critical marine mammal biological functions such as foraging, communication, and navigation. Commercial shipping contributes significantly to the ocean soundscape, typically dominating the noise field at frequencies less than 500 Hz. Market conditions, trends in vessel design and propulsion, use of more economical ship routes, operational efficiency, and environmental factors are all important variables that help shape the changing soundscape. To reliably model the temporal and spatial variability of a regional soundscape, accurate characterization of the sources of noise is needed. Acoustic recordings taken at the Point Sur Ocean Acoustic Observatory (OAO) and Automatic Identification System (AIS) reports broadcast by ships passing the OAO site have been used to determine ship source levels over the 25–600 Hz band, categorized by ship class and speed. Source levels are then applied to a model used to evaluate temporal variability of the noise field at several sites along the central California coast based on AIS-reported shipping traffic transiting the region. Results of our calculations are presented and discussed. [Research supported by US Navy CNO(N45).]
Passive acoustic monitoring near Pt. Sur, California, in 2008–2009.
Authors: Margolina Tetyana , Miller Christopher , Joseph John E. , Chiu Ching-Sang , Collins Curtis A.
Published: July 2011

How sounds from human activities affect behavior of marine mammals is in focus of many ongoing research projects. An important step in this direction is to develop regional databases of marine mammal vocalizations and sounds generated by human activities and natural sources. Analysis of passive acoustic recordings collected on top of Sur Ridge, near the Point Sur Ocean Acoustic Observatory (OAO), in 2008–2009 is presented. The data have been acquired with high-frequency acoustic recording package in the 10 Hz–100 kHz frequency band at a 200 kHz sampling frequency. These recordings have been scanned to detect and identify signals from various underwater acoustic sources. Pressure spectrum level has been analyzed in time/frequency space to reveal interannual, seasonal, and diel variabilities, as well as possible correlations of different sounds, with primary focus on anthropogenic sounds and marine mammal vocalizations. [Research supported by US Navy CNO(N45).]
Acoustic characterization of pingers on Queensland Shark Control nets.
Authors: Erbe Christine , McPherson Craig , Craven Andrea
Published: July 2011

Active acoustic applications in marine bioacoustics include the use of pingers to dissuade marine mammals. Pingers are most frequently used by the fishing industry to prevent depredation and entanglement. Pingers are also used by other marine industries to dissuade animals from potentially dangerous sites, e.g., underwater turbines. The Queensland Shark Control uses pingers to prevent marine mammal entanglement in shark control nets along public beaches. We have recorded and characterized some of the most common pingers off Queensland. Sound propagation and the potential detection of pinger sounds by marine mammals were modeled. Ambient noise was recorded in the vicinity of shark nets to estimate the contribution of pingers to ambient sound budgets. [Work supported by the Australian Department of the Environment, Water, Heritage and the Arts; Australian Antarctic Division.]
Application of active acoustic techniques to studies of krill aggregation and interaction with higher predators.
Authors: Lawson Gareth L. , Lavery Andone C. , Wiebe Peter H. , Copley Nancy J.
Published: July 2011

Large aggregations of euphausiids are often observed in regions of abrupt topography such as continental shelf breaks and submarine canyons. Understanding the biological and physical factors that lead to such aggregations is an important problem as these regions often constitute key habitat for top predators. A series of three cruises was conducted to the margins of Georges Bank, sampling zooplankton with a broadband active acoustic system, a multi-frequency acoustic system, a video plankton recorder, and depth-stratified nets, and sampling seabirds and marine mammals via visual observations. A combination of coarse-scale acoustic mapping and fine-scale adaptive surveys were used to identify and track individual euphausiid aggregations and to observe how their structure and vertical position varied with changing conditions. Distinct spatial and temporal variabilities were observed in euphausiid abundance, patch structure, and community composition, along with changes in the abundance and distribution of higher predators. These cruises represent among the first uses of the broadband technology for the study of zooplankton ecology and allow for an assessment of the relative advantages and disadvantages of broadband vs multifrequency approaches and of the importance of independent ground-truthing information.
Seasonal and spatial patterns of cetacean occurrence off Oahu, HI observed acoustically.
Authors: Lammers Marc O. , Richlen Michael , Au Whitlow W. L. , Rosinski Anne E. , Perez Andujar Gadea
Published: July 2011

The seasonal occurrence and distribution of cetaceans around island archipelagos is often poorly understood. This is generally due to the variability in sea surface conditions associated with islands, which make visual surveys prohibitive along exposed areas and/or during seasonal periods of rough seas. Historically, this has been the case for many cetacean species found in Hawaiian waters. Recently, however, concerns about the impacts of anthropogenic activities have created a need to better understand the long-term, spatial and temporal distributions of cetaceans in the archipelago. To meet this need, an effort was begun in February 2009 to study cetacean occurrence around the island of Oahu using a network of passive acoustic recorders. Five ecological acoustic recorders (EARs) were deployed in waters 115–575 m deep along the perimeter of the island and refurbished approximately every 4 months. Data from these deployments are providing an unprecedented perspective on the occurrence of both odontocete and mysticete cetaceans around the island. The southeastern corner of Oahu, in particular, has emerged as a hotspot of odontocetes; diversity and abundance. This and two other sites being monitored have historically received little or no visual survey attention, but are clearly important habitats for a variety of species.
Real-time tissue change monitoring during the treatment of prostate cancer using Sonablate 500 with high intensity focused ultrasound.
Authors: Chen Wo-Hsing , Sanghvi Narendra T. , Carlson Roy F. , Schatzl Georg , Marberger Michael
Published: July 2011

Tissue change monitoring (TCM) during HIFU is an essential required feedback during the HIFU treatment. The Sonablate 500 (SB500) HIFU is enhanced with quantitative, real-time TCM software that estimate changes in tissue properties due to HIFU treatment of prostate cancer. TCM generates energy reading based on spectral analysis of the two-dimensional rf backscattered ultrasound signals acquired during HIFU. These energy changes are correlated to tissue temperature. TCM results are overlaid on the real-time ultrasound image in green, yellow, and orange to represent low, medium, and high degree of change in backscattered energy levels. To validate the TCM process five patients with histologically confirmed, organ confined prostate cancer were enrolled for the study. Needles containing three thermocouples were placed transperineally under TRUS guidance in the prostate to monitor temperatures from focal zone, posterior to the focal zone and on the lateral gland where no HIFU was applied. The measured temperatures in the HIFU treatment zones were from 70–114 °C (average 84 °C). The TCM results, estimated tissue temperatures were from 75 to 100 °C for 83% of treatment sites with an average tissue temperature of 91 °C.
Numerical simulation of bubble dynamics in deformable vessels.
Authors: Coralic Vedran , Colonius Tim
Published: July 2011

The growth and collapse of cavitation bubbles has been implicated as a potential damage mechanism leading to the rupture of blood vessels in shock wave lithotripsy (SWL) [Bailey et al., in The Fifth International Symposium on Cavitation, Osaka, Japan (2003)]. While this phenomenon has been investigated numerically, the resulting simulations have often assumed some degree of symmetry and have often failed to include a large number of influential physics, such as viscosity, compressibility, surface tension, phase change, and fluid-structure interactions (FSI). We present here our efforts to explore the role that cavitation bubbles play in the rupture of blood vessels in SWL and to improve upon the current state of the numerical approach. We have developed a 3-D, high-order accurate, shock- and interface-capturing, multicomponent flow algorithm that accounts for the effects of surface tension and FSI. The preliminary results for the case of a bubble collapse, induced by a shock wave lithotripter pulse and occurring inside a deformable vessel, are presented. [This research was supported by the NIH (Grant No. 2PO1DK043881.]
Indoor human response to blast noise measured in situ.
Authors: Swift S. Hales , Valente Dan , Nykaza Edward T. , Hodgdon Kathleen
Published: July 2011

As a result of suburban sprawl, the number of people living near military installations is drastically increasing. Coupled with an escalation of military activities and preparedness, the potential for noise generated by an installation to impact the surrounding communities has grown, especially for large amplitude impulsive events such as those generated during artillery training exercises. To assess the effect of blast noise on individuals living near installations, a large scale in situ study has been performed. The homes of study participants were instrumented and outdoor/indoor blast signature pairs of routine installation activities were captured over the course of 1 year. Participants filled out short questionnaires whenever they heard blast noise events. Measurements of single events at subjects’ homes along with their responses present unique data with which to investigate the human response to blast noise on an event-by-event basis. In this presentation, the characteristics of the noise typically experienced by residents in their own homes will be examined and used to create dose-response relationships. Comparison will be made of dose-response curves based on annoyance, interference, and loudness as a function of level-based metrics, and as a function of a variety of psychoacoustic metrics. [Work supported by the Strategic Environmental Research and Development Program.]
Comparison of subjective test methodologies for assessing human annoyance to low-amplitude sonic booms.
Authors: Miller Denise M. , Sparrow Victor W.
Published: July 2011

In a subjective test assessing human annoyance to low-amplitude sonic booms, different subjective testing methods were utilized. These included a hybrid categorical line scaling method as well as magnitude estimation with two different reference sounds. The test methods will be discussed, as well as their advantages and disadvantages. Other topics of discussion will include experimental design, data analysis, as well as subject participant preference. [Work sponsored by the NSF and the FAA through the PARTNER Center of Excellence.]
Evaluation of new indoor sonic boom subjective test facility at NASA Langley Research Center.
Authors: Loubeau Alexandra , Rathsam Jonathan , Klos Jacob
Published: July 2011

A sonic boom simulator at NASA Langley Research Center has been constructed for research on human response to low-amplitude sonic booms heard indoors. Research in this facility will ultimately lead to a psychoacoustic model for single indoor booms that will be validated by future community studies. The first subjective test was designed to explore indoor human response to variations in sonic boom rise time and amplitude. Another goal was to identify variability across listener locations within the facility. Finally, the test also served to evaluate the facility as a laboratory research tool for studying indoor human response to sonic booms. Subjects listened to test sounds and were asked to judge the annoyance relative to a reference boom. Measurements of test signals were conducted for objective analysis and correlation with subjective responses. Results confirm the functionality of the facility and effectiveness of the test methods and indicate that calculated loudness does not fully describe the indoor annoyance.
Sonic-boom loudness test using new indoor sonic-boom subjective-test facility at NASA Langley Research Center.
Authors: Rathsam Jonathan , Loubeau Alexandra , Klos Jacob
Published: July 2011

A sonic-boom simulator at NASA Langley Research Center has been constructed to research the human response to low-amplitude sonic booms heard indoors. The facility’s initial goal is the development of a psychoacoustic model for individual sonic booms to be validated by future community studies. The current test assesses the suitability of existing loudness metrics for predicting indoor human annoyance to sonic-boom waveforms. The test signals consist of synthesized and recorded sonic-boom waveforms chosen to systematically vary the low-frequency content. Some waveforms are presented with and without high-pass filtering to examine the effect of low-frequency content on annoyance. Equally annoying presentation levels are determined among the test signals by paired comparison with a reference sonic-boom waveform. A second reference waveform is also used for some signals to examine if results change with the reference sound. Loudness metrics are then calculated for each measured test signal at the subjective-equality level. Loudness metrics are thus evaluated based on their ability to predict annoyance for a wide range of sonic-boom waveforms.
A noise mapping study for heterogeneous road traffic conditions considering horn sounds.
Authors: Ramasamy Kalaiselvi , Alur Ramachandraiah
Published: July 2011

In recent years noise mapping has become an increasingly useful tool for environmental noise assessment. Noise mapping is the process of determining and visualizing noise impact on the environment. The current noise mapping softwares are typically designed for the express and freeways of other countries where the roads are widely open with the homogeneous traffic conditions and speeds of vehicles touching 100 km/h. This situation is not suitable for Indian conditions where heterogeneity of traffic and honking of vehicles are the characteristics in an urban environment. A pilot study in typical areas of a metropolitan city (Chennai city) using soundplan software shows a difference of up to 7 to 10 dB(A) in Lden values between obtained and measured noise levels. A multiple regression model has been developed taking into account the horn aspects and heterogeneity. The statistical parameters such as L10, L50, L90, and Leq are measured along with the vehicle speed. The vehicle count and number of horn events are also observed during the field measurements with the video camera. The developed multiple regression models can be used as a plug-in in any open source GIS softwares such as QGIS, GRASS, etc., for noise mapping purposes. With this background this paper explains a methodology to build 3-D noise models for urban areas to analyze and visualize the 3-D distribution.
A study of noise mitigation techniques for explosive training scenarios.
Authors: Swearingen Michelle E. , Albert Donald G. , Valente Dan
Published: July 2011

Utilizing explosives to destroy questionable munitions is a standard procedure in the military. It is critical to have teams trained to perform these activities safely. Often the training involves practice in setting up and detonating relatively small charges of explosives, but these activities can cause annoyance in surrounding civilian populations. A study was performed at one military installation to determine best practices for managing the noise generated by these activities. Three methods were investigated: burying charges with sandbags, covering charges with a rubber blast mat, and spraying water over the charges during detonation. Acoustic and seismic measurements were performed at several distances between 4 and 2500 m in two directions to investigate the relative effectiveness of each method. The study found that covering the charges with sandbags provided a reduction in noise levels of as much as 15 dB in the far field with minimal impact on the training. Use of sandbags was therefore superior to the other methods investigated in maximum reduction, ease of use, and cost. This presentation will provide an overview of the study results.
Attenuation mechanism for slurry in contact with ultrasonic diffraction grating.
Authors: Greenwood Margaret S.
Published: July 2011

Attenuation measurements for ultrasound penetrating a slurry in contact with an ultrasonic diffraction grating were presented at the Paris ASA meeting (Proceedings of Meetings on Acoustics, 4, 045017). Also, the viscous-inertial model was suggested as the mechanism, in which the attenuation is due to the dissipation in the thin boundary layer of liquid surrounding the particle. Further, it was proposed that, in order for the dissipation to occur, the circumference of the particle must be equal to or greater than 1 ultrasonic wavelength. Measurements will be reported for the following slurries in contact with a grating using a 1 MHz transducer: (1) 275-μm diameter polystyrene spheres, (2) 671-μm polystyrene spheres, and (3) 1588-μm acrylic spheres using a diffraction grating with a 1 MHz transducer. Attenuation was observed for slurry cases 2 and 3. However, no attenuation could be observed for the slurry of 275-μm diameter polystyrene spheres in water even at a volume fraction of 0.4; the signal was the same as that for water. Since the circumference for the 275-μm diameter particles was less than wavelength in water, these data provide confirmation of the proposed mechanism. Also, such measurements provide a method of exploring the viscous-inertial model.
Cochlea-scaled entropy predicts speech intelligibility when intensity is scaled as linear amplitude or as loudness, but not when scaled logarithmically.
Authors: Stilp Christian E. , Kluender Keith R.
Published: July 2011

Stilp and Kluender [Proc. Natl. Acad. Sci. 107, 12387–12392 (2010)] reported sentence intelligibility to be well-predicted by measures of sensory change over time [cochlea-scaled spectral entropy (CSE)] and not consonants, vowels, or duration of signal replaced. As greater amounts of CSE were replaced by noise, intelligibility worsened. They calculated CSE as Euclidean distances between spectra defined by linear amplitude as a function of equal rectangular bandwidth (ERB). The present experiments compare measures of speech intelligibility as a function of CSE when amplitude is measured on a linear scale as before and when log-scaled (dB) or loudness-scaled (sone). Listeners typed all words they understood after hearing sentences with 80- and 112-ms segments replaced by speech-shaped noise. Log-scaled (dB) CSE was a poor predictor of performance. Both linear-scaled and loudness-scaled measures of CSE predict intelligibility very well, replicating Stilp and Kluender. Linear and loudness scales will be discussed in the context of upward spread of masking and two-tone suppression as they relate to speech signals. These perceptual findings suggest that conventional use of spectrograms (linear frequency × dB intensity) could systematically misinform researchers concerning properties of speech signals that are most useful to listeners. [Work supported by NIDCD.]
Cues above 4 kilohertz can improve spatially separated speech recognition.
Authors: Puria Sunil , Carr Levy Suzanne , Freed Daniel J. , Nilsson Michael
Published: July 2011

There are multiple acoustic cues above 4 kHz that may be used to improve speech recognition in noisy environments. This study tests this hypothesis with spatially separated speech maskers. The reception threshold of speech (RTS) was measured in two conditions: (1) asymmetric condition with target speech at −45° and maskers at +45°, and (2) diffuse condition with speech at 0° and one masker at each of four quadrants around the listener (±45°, ±135°). HINT sentences were rerecorded using a male talker and a 22.05 kHz bandwidth while different males were recorded speaking the television and rainbow as maskers. SRTs were measured with all materials low-pass filtered at 4, 6, 8, and 10 kHz for the asymmetric and diffuse conditions. 12 normal hearing subjects (on the way to 24) were tested using free-field loudspeakers in a sound booth. The mean RTSs for the asymmetric condition were −17.43, −19.07, −19.34, and −20.65 dB for 4, 6, 8, and 10 kHz, respectively. For the diffuse condition the mean RTSs were −7.77, −9.00, −9.88, and −10.05 dB for the same frequencies. The results suggest that high-frequency acoustic cues can enhance the ability to segregate spatially separated speech.
Room reverberation and constancy in sparse noise-vocoded speech.
Authors: Watkins Anthony , Raimond Andrew , Makin Simon
Published: July 2011

Speech played several metres from the listener in a room is usually heard to have much the same phonetic content as it does when played nearby, although the different amounts of reverberation at these distances make the temporal envelopes of these signals very different. To study this “constancy” effect, listeners heard natural-speech messages and noise-excited vocoder versions of them. The vocoder used eight auditory-filter shaped noise-bands, each with the temporal envelope arising in that filter when the speech message is played. The center frequencies of the equally log-spaced bands ranged from 250 Hz to 4.24 kHz. An 11-step “sir-to-stir” continuum was formed by amplitude modulation and each step was played in the context, “next you’ll get … to click on.” Listeners identified test words appropriately, even in the eight-band conditions where the speech had a robotic quality. Constancy was assessed by comparing the influence of reverberation on the test word across conditions where the context had either the same level of reverberation (i.e., from the same, far distance), or where it had a much lower level (i.e., from nearby). Constancy effects were obtained with both the natural- and the eight-band speech, with the higher-frequency bands having more importance.
Fluid-structure interaction and inverse design simulations for highly flexible turbomachinery.
Authors: Campbell Robert L.
Published: July 2011

Highly flexible turbomachinery offers substantial advantages for biomedical implantation but can suffer from performance losses due to blade deformations during operation. The objective of this work is to develop a method to define an impeller shape that deforms into the design shape during operation, thereby making feasible a collapsible impeller for medical implantation without incurring performance losses due to blade flexibility. A fluid-structure interaction (FSI) solver is developed and validated for quasi-steady operation, capable of modeling the time-dependent deformation inherent to the impeller polymeric material. The solver is validated using experimental data for a modified NACA 66 fin at various angles of attack. Inverse design simulations are used to define blade geometry that deforms into the design shape after being subjected to quasi-steady flow at prescribed conditions for a specified amount of time. The validated FSI solver is used to confirm performance of the inverse design shape. Evaluation of the FSI solver convergence shows the fluid and structure are nearly fully converged after only a few sub-iterations for these quasi-steady simulations. Performance studies show that the flow solver consumes most of the processing time, with the mesh motion and structure solutions requiring a much smaller fraction of the total processing time.
Scattering of acoustic quasi-Gaussian beams and Bessel beams by fluid-loaded spheres: Exact solutions and physical interpretation.
Authors: Marston Philip L.
Published: July 2011

Exact solutions are available for the scattering of sound by spheres placed on the axis of certain types of acoustic beams. In the case of an acoustic Bessel beam the scattering for various elastic spheres is greatly modified relative to the standard case of plane-wave illumination [P. L. Marston, J. Acoust. Soc. Am. 122, 247–252 (2007)]. Symmetry and geometric considerations explain why selected sphere modes can be suppressed in a way that depends on the Bessel beam parameters. The quasi-Gaussian case is treated by an appropriate superposition of zero-order Bessel beams displaying the focal properties of a Gaussian beam [P. L. Marston, submitted]. This superposition, unlike the case of a paraxial Gaussian beam, is an exact solution of the Helmholtz equation. The sphere is centered on the focal point of the beam and the scattering follows by superposition from the Bessel beam case. While not prone to suppress specific modes of the sphere, the quasi-Gaussian case can also modify the scattering for a wide range of beam parameters and frequencies. Mode amplitudes are modified by a function depending on a ratio of incomplete gamma functions and the size of the focus of the beam. [Work supported by ONR.]