bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of platelet‐derived microparticles in stored apheresis platelet concentrates on polymorphonuclear leucocyte respiratory burst
Authors: Xie R. F. , Hu P. , Li W. , Ren Y. N. , Yang J. , Yang Y. M. , Wang Z. Y. , Fan H. H.
Published: October 2013

Background and Objectives

Platelet‐derived microparticles (PMPs) and other proinflammatory mediators, which are accumulated during the storage process, might induce transfusion adverse events. We hypothesized that the PMP primed polymorphonuclear neutrophil (PMN) respiratory burst after the transfusion, which could be linked to the transfusion‐related acute lung injury (TRALI).

Materials and Methods

The PMPs were isolated by centrifugation of the platelet‐free plasma from 10 apheresis platelet concentrates (A‐PLTs) at 20 000 × g for 1 h. The PMPs were counted by flow cytometric analysis, followed by Western blotting, that were performed on isolated PMPs. The soluble CD40 ligand (sCD40L, sCD154) was assayed with ELISA. The priming of the formyl‐Met‐Leu‐Phe (fMLP)‐activated PMN respiratory burst was measured with the hydrogen peroxide production.

Results

The PMP counts increased by 1·7‐folds after 3 days of storage. Meanwhile, sCD40L also significantly increased in PMP fraction isolated from the 3‐day stored A‐PLTs. Furthermore, Western blotting indicated that sCD40L was involved and concentrated in PMP. The PMPs were able to effectively prime the fMLP‐activated PMN respiratory burst, which was partly inhibited by CD154 monoclonal antibody or by filtration with 0·1 μm membrane. Significant relativity was existed between the PMP counts, sCD40L and priming activity during the A‐PLT storage.

Conclusion

The platelet‐derived microparticles, which carried the sCD40L, accumulated in the apheresis platelet concentrates during the 5 days of storage. They primed the fMLP‐activated PMN respiration burst, which might be relative to TRALI.
Mixed Convection Stagnation-Point Flow Past a Vertical Flat Plate With a Second Order Slip
Authors: Roşca Alin V. , Pop Ioan
Published: October 2013

An exact similarity solution of the steady mixed convection flow of a viscous and incompressible fluid in the vicinity of two-dimensional stagnation-point with a second-order slip condition has been investigated. Using appropriate similarity variable, the Navier–Stokes equations coupled with the energy equation governing the flow and heat transfer are reduced to a system of nonlinear ordinary (similarity) equations, which are well-posed. These equations are solved numerically in the buoyancy assisting and opposing flow regions. It is found that a reverse flow region develops in the buoyancy opposing flow case, and dual (upper and lower branch) solutions are found to exist in the case of opposing flow region for a certain range of the negative values of the mixed convection parameter. A stability analysis has been performed, which shows that the upper branch solutions are stable and physically realizable in practice, while the lower branch solutions are not stable and, therefore, not physically realizable in practice. The numerical results have been compared with those reported in the literature, the agreement being excellent.
Computational Fluid Dynamics and Particle Image Velocimetry Supported Examination of Bidirectional Velocity Probes for Measurements in Flames
Authors: Yilmaz Nadir , Hogan Brian C. , Bocanegra Humberto , Burl Donaldson A. , Gill Walt
Published: October 2013

The bidirectional velocity probe has been used in various flames to measure local velocity. The device is based on the pressure difference between a closed forward facing cavity and a closed rearward facing cavity. The probes have been noted to indicate a pressure difference greater than that which would be predicted based on Bernoulli's equation. Each device must be experimentally calibrated in a wind tunnel at similar Reynolds number to determine its “amplification factor.” This study uses PIV, flow visualization and CFD to examine the flow field around the probe, as well as an experimental study which compares various probe configurations for measurement of velocity by pressure differential. The conclusion is that the amplification factor is indeed greater than unity but use of the wind tunnel for calibration is questionable.
A Comparative Thermoeconomic Study of Hybrid Solar Gas-Turbine Power Plants
Authors: Spelling James , Laumert Björn , Fransson Torsten
Published: October 2013

The construction of the first generation of commercial hybrid solar gas-turbine power plants will present the designer with a large number of choices. To assist decision making, a thermoeconomic study has been performed for three different power plant configurations, namely, simple- and combined-cycles along with a simple-cycle with the addition of thermal energy storage. Multi-objective optimization has been used to identify Pareto-optimal designs and highlight the trade-offs between minimizing investment costs and minimizing specific CO2 emissions. The solar hybrid combined-cycle power plant provides a 60% reduction in electricity cost compared to parabolic trough power plants at annual solar shares up to 20%. The storage integrated designs can achieve much higher solar shares and provide a 7–13% reduction in electricity costs at annual solar shares up to 90%. At the same time, the water consumption of the solar gas-turbine systems is significantly lower than conventional steam-cycle based solar power plants.
The Onset of Convection in an Internally Heated Nanofluid Layer
Authors: Nield D. A. , Kuznetsov A. V.
Published: October 2013

We analytically studied the onset of convection, induced by internal heating, such as that produced by microwave heating or chemical reaction, in a horizontal layer of a nanofluid subject to Brownian motion and thermophoresis. This is a fundamentally different situation from traditionally studied heating from below. Convection, when it occurs, is now concentrated in the portion of the layer where the upward vertical gradient is negative, which is the upper portion of the layer. The situation of internal heating also allows employing more realistic boundary conditions than those hitherto used.
Turbulent Consumption Speeds of High Hydrogen Content Fuels From 1–20 atm
Authors: Venkateswaran Prabhakar , Marshall Andrew D. , Seitzman Jerry M. , Lieuwen Tim C.
Published: October 2013

This work describes measurements and analysis of the turbulent consumption speeds, ST,GC, of H2/CO fuel blends. We report measurements of ST,GC at pressures and normalized turbulence intensities, urms'/SL,0, up to 20 atm and 1800, respectively, for a variety of H2/CO mixtures and equivalence ratios. In addition, we present correlations of these data using laminar burning velocities of highly stretched flames, SL,max, derived from quasi-steady leading points models. These analyses show that SL,max can be used to correlate data over a broad range of fuel compositions but do not capture the pressure sensitivity of ST,GC. We suggest that these pressure effects are more fundamentally a manifestation of non-quasi-steady behavior in the mass burning rate at the flame leading points.
Design challenges and coordination issues in hotel projects
Authors: Saunders Melvin L. , Marsh David
Published: October 2013

The design of a Five Star hotel facility encompasses a myriad of design dilemmas. On the same note, the design of a One Star or Two Star hotel has many dilemmas of its own. The ability of an acoustical consultant, as an integral part of the design team, to recognize the differences between these types of projects can be the difference between a successful hotel project and miserable failure. Different quality hotels require different levels of design criteria. Proper coordination and timing between trades and installations, such as loudspeakers, ceiling coffers, chandeliers, sprinkler heads, and ductwork, is also very important for the success of the overall project. This paper will discuss techniques and methods to produce successful hotel projects, as well as various noise sources throughout these spaces. It will also highlight a number of tips learned through many hotel design experiences.
Nocturnal sound production by longspine squirrelfish (Holocentrus rufus) with notes on sound production by fishes on the Turneffe Atoll coral reef in Belize
Authors: Luczkovich Joseph , Stewart Christopher , Sprague Mark
Published: October 2013

Reef fishes produce sounds in response to disturbance, during agonistic encounters in defense of territories, and in spawning events. We recorded in captivity the disturbance sounds of reef fishes in the grunt family (Haemulidae), triggerfish family (Balistidae), and squirrelfish family (Holocentridae) in Belize. Using these recordings and published sonograms for reef fishes, we have identified longspine squirrelfish (Holocentrus rufus) in field recordings made on Calabash Caye, Turneffe Atoll, in Belize. We monitored the production of sound by longspine squirrelfish over the course of a transition from day to night. The calling rate of the longspine squirrelfish was greatest after sunset, suggesting that the increased activity of these fish was due to their nocturnal agonistic behavior. A sonobuoy that recorded on a timer 90 s every hour for 24 h failed to detect any longspine squirrelfish calls, perhaps due to their intermittent nature. An unknown sound of biological origin was detected on the sonobuoy recording, but it did not match any of the captive species recorded. A reef fish sound catalogue from captive individuals is being collected for use in the identification of unknown sounds and to monitor the condition of the reefs remotely.
Sound production by the toadfish Sanopus astrifer
Authors: Mann David A. , Ma Wei-Li Diana , Lobel Phillip S.
Published: October 2013

Sounds produced by the toadfish Sanopus astrifer were recorded at Glovers Atoll, Belize. These are the first recorded sounds by a toadfish in the Sanopus genus. The boatwhistle call is similar to the boatwhistle produced by Opsanus species, in that it consists of a harmonic call about 250 ms in duration with a fundamental frequency of about 180 Hz. Boatwhistles are made in bouts of 1–4 boatwhistles with an inter-boatwhistle interval of 140–170 ms. The first boatwhistle in a bout tends to be longer than subsequent boatwhistles. S. astrifer also shows the acoustic tagging phenomenon described by Fine and Thorson for Opsanus beta, in which the male produces a short grunt during calling by another male. However, instead of tagging during the boatwhistle like Opsanus, Sanopus tags between boatwhistles in a bout.
Larval orientation to reefs and reef sound
Authors: Montgomery John , Tolimieri Nicholas , Jeffs Andrew
Published: October 2013

Reef systems form a discontinuous spatial mosaic leading many reef organisms to have a dispersal phase in their early life history. At the end of this phase, the larvae must settle onto a reef. Recent evidence supports the view that both larval fish and invertebrates are more active participants in finding suitable settlement habitat than had previously been thought. Not only are they more active swimmers, but field evidence shows that they orient toward reefs from some distance away. Of the possible distance clues, sound is potentially one of the most attractive. Both abiotic and biotic sounds provide habitat-specific information that propagates well underwater and can convey directional clues. Using a combination of reef sound replay, light traps, and choice chambers, it has been shown that larval fish and invertebrates can be attracted to reef sound. Hearing in most fish is based on the otoliths of the inner ear that detect displacement in the sound field. Current theory holds that otolithic hearing is capable of detecting the axis of sound propagation, but not the direction to the source. These experiments provide evidence that fish larvae (even those without a swimbladder) can resolve this 180 degree ambiguity.
The application of passive acoustics to assess, monitor, and protect the coral reef ecosystems of the U.S. Pacific Islands
Authors: Brainard Russell E. , Wong Kevin B. , Ferguson Scott , Timmers Molly
Published: October 2013

Activities of the NOAA Fisheries Honolulu Laboratory Coral Reef Ecosystem Investigation (CREI) are presented and areas where the application of passive acoustic methods may significantly contribute to scientific, management, and operational objectives are highlighted. To understand coral reef ecosystems and to reduce adverse human impacts are two fundamental themes of The National Action Plan to Conserve Coral Reefs. The CREI was established to assess, monitor, map, restore, and protect the coral reef ecosystems of the U.S. Pacific Islands. Activities include rapid ecological assessments of fish, corals, algae, and invertebrates, digital video surveys of habitat and fish, acoustic seabed classification surveys, an in-situ collection of oceanographic conditions, and satellite remote sensing observations. Resource constraints and the large distances between the U.S. Pacific Islands often limit in-situ work to 1–2 years between site visits and prevent adequate temporal monitoring of the biological responses. We propose to develop passive acoustic techniques to monitor some aspects of the health of these remote ecosystems and to develop warning systems to elert scientists and resource managers of large changes or potential threats.
David Weston—Ocean science of invariant principles, total accuracy, and appropriate precision
Authors: Roebuck Ian
Published: October 2013

David Weston’s entire professional career was as a member of the Royal Navy Scientific Service, working in the field of ocean acoustics and its applications to maritime operations. The breadth of his interests has often been remarked upon, but because of the sensitive nature of his work at the time, it was indeed much more diverse than his published papers showed. This presentation, from the successors to the laboratories he illuminated for many years, is an attempt to fill in at least some of the gaps. The presentation also focuses on the underlying scientific philosophy of David’s work, rooted in the British tradition of applicable mathematics and physics. A deep appreciation of the role of invariants and dimensional methods, and awareness of the sensitivity of any models to changes to the input assumptions, was at the heart of his approach. The needs of the Navy kept him rigorous in requiring accuracy, and clear about the distinction between it and precision. Examples of these principles are included, still as relevant today as they were when he insisted on applying them 30 years ago.
Ten years of hydroacoustical observations of the behavior and distribution of small pelagic fish in the west coast of Baja California, Mexico
Authors: Robinson Carlos
Published: October 2013

The main goal is to present results on the behavior and distribution of small pelagic fish on the west coast of Baja California, Mexico using hydroacoustics and related to oceanographic parameters. From December 1993 to September 2002, 20 oceanographic surveys have been done off the west coast of Baja California, Mexico aboard the R/V ‘‘El Puma.’’ Two areas are covered, a Northern area from Punta Colnet to Punta Baja (30 54′, 116 40′ W to 29 26′ N 115 29′ W) and a Southern area from Punta Eugenia to Bahia Tortugas (27 29′ N 115 22′ W to 26 47′ N 113 55′ W). Results show that since 1993 echo-counting has been reduced significantly in both areas. Results are discussed in terms of oceanographic parameters and the presence of the 1997 El Niño. Before the 1997 El Niño, echo-counting was high in both areas. The behavior is reversed during El Niño. However, in the central area results from March 2000 may suggest a possible change in this tendency.
In situ acoustic estimates of the swimbladder volume of Atlantic herring, Clupea harengus
Authors: Nero Redwood W. , Thompson Charles H. , Jech J. Michael
Published: October 2013

Most marine fish maintain swimbladder volumes equivalent to 4%–5% of their body weight in order to maintain neutral buoyancy. In many fish the addition or removal of gas from the swimbladder is accomplished with the gas gland, a blood invested portion of the swimbladder wall. However, several families, including the herring family, Clupeidae, lack a gas gland. Instead, these fish possess a pneumatic duct between the esophagus and the swimbladder by which they are believed to inflate their swimbladders by ‘‘gulping’’ atmospheric air at the sea surface. Acoustic measurements at 1.5–5 kHz on fish in the Gulf of Maine showed a swimbladder resonance peak near 2.3 kHz at 180 m depth. Midwater trawls confirmed that the fish were Atlantic herring (Clupea harengus) of 19–28 cm length. Calculations using a model of swimbladder resonance gives swimbladder volumes of 1.3% at 180 m. Extrapolation using Boyle’s law suggests that at the sea surface, these herring would need to inflate their swimbladders by up to four times the volume required for neutral buoyancy. In general, swimbladders of the Clupeidae may resonate at lower frequencies than previously expected. [Work supported by ONR and NMFS.]
Tidal matched field processing inversion for water depth and source range in the Intimate96 test
Authors: Tolstoy A. , Jesus S. , Rodríguez O.
Published: October 2013

Examining Intimate96 hydrophone data (300 to 800 Hz) we see clearly the effects of tidal changes, i.e., of changing water depths. In this work we will examine Matched Field Processing (MFP) sensitivity at that range of frequencies to expected tidal changes (the depth varies ±1.0 m from the nominal of 135 m). Is it possible to invert such data to accurately and uniquely estimate water depth D as a function of time (tides)? What about accurate, unique, simultaneous estimates of source range rsou? What happens when we use multiple frequencies and when D is known to shift in a predictable fashion? Can the rsou vs D ambiguity ever be resolved for a successful, unique MFP inversion for those parameters?
A short history of acoustical microscopy
Authors: Jones Joie
Published: October 2013

Optical microscopy has a long and interesting history, going back thousands of years to discoveries made in both Assyrian and Mayan cultures. Acoustical microscopy, on the other hand, has had a much shorter but equally interesting history, going back only to the mid-20th century. This presentation traces the development of acoustical microscopy from its very beginnings to the present. Comparisons with other microscopic techniques will point out the unique features offered by acoustical microscopy. A wide range of application areas will be reviewed and future prospects and potentials discussed.
Scanning tomographic acoustic microscopy
Authors: Lee Hua
Published: October 2013

This paper provides an overview of the design and development of the scanning tomographic acoustic microscopy (STAM). This research effort spans over a period of more than 12 years, which successfully elevated the acoustic microscopy from the traditional intensity-mapping mode to the level of holographic and tomographic imaging. The tomographic imaging capability of STAM was developed on the platform of the scanning laser acoustic microscope (SLAM), which operates in a coherent transmission mode with plane-wave illumination and scanning laser wavefield detection. The image formation techniques were based on the backward propagation method implemented in the plane-to-plane format. In this paper, the key elements of the design and development, including the modification of the data-acquisition hardware, implementation of image reconstruction algorithms for multiple-frequency and multiple-angle tomography, and the high-precision phase-correction and image registration techniques for the superposition of coherent sub-images, will be discussed. Results of full-scale experiments will also be included to demonstrate the capability of holographic and tomographic image formation in microscopic scale.
Intravascular ultrasound: From the acoustic microscope into the catheterization laboratory
Authors: van der Steen Antonius F. W. , de Korte Chris L. , Slager Cornelis J.
Published: October 2013

One of the explicit goals of acoustic microscopy (AM) of biological tissues is to gain information and insights in vitro that will improve clinically used diagnostic ultrasound. This lecture will focus on the transfer of knowledge on vascular ultrasound obtained from acoustic microcopy to interventional cardiology. Spectral AM has shown that calcified atherosclerosis can be discriminated from fibrous and fatty plaques. The discrimination between fibrous and fatty plaques is less pronounced, but AM has shown these have distinct different anisotropy properties. Furthermore, it has been shown in vitro that fibrous tissues have much higher Youngs moduli than fatty tissues. AM has also shown that endothelial cells are sensitive to shear stress. In the catheterization laboratory this knowledge plays an important role in vulnerable plaque detection. A vulnerable plaque is a nonobstructing plaque consisting of a fatty pool covered by a thin fibrous cap. Breaking of the cap annually kills 225000 people in the USA. A combination of biplane angiography, 3D IVUS and computational fluid dynamics allows one to determine shear stress at the endothelium. This has proven to be a predictor for the long term outcome of interventions such as balloon angioplasty and (drug eluting) stent placement.
The acoustical Klein–Gordon equation: A time-independent perturbation analysis
Authors: Forbes Barbara J.
Published: October 2013

The acoustical Klein–Gordon equation, describing one-dimensional wave propagation in a duct of varying cross-section, is discussed. Dispersive solutions, not elucidated by the Webster equation, are examined and perturbative geometric ‘‘potentials’’ are defined. A time-independent, first-order expression for the perturbed eigenfunctions—defined as the potential energy per unit length of duct—is derived. Eigenvalue shifts are defined in terms of a sinusoidal perturbative term, and Ehrenfest’s theorem is used to obtain the first-order shifts in the duct resonances. It is found that the perturbation may be in or out of phase with the radiation pressure, thus strengthening or weakening the resonances, respectively; and that the perturbation may raise, lower, or have no effect on the resonance frequencies, depending on the interaction of the phases of the terms. The results are compared with the standard theory of pipe resonances, which assumes perturbations to the cross-section of the pipe rather than directly to the eigenvalues.
Holographic interferometry and finite element modeling of handbells
Authors: Buschert John R.
Published: October 2013

Holographic interferometry was used to map out the vibration modes of a C4 handbell. A finite element model (FEM) of the handbell was also created. The FEM program can be made to present its results in a graphic format which mimics the stripes seen in interferometry. Thus, the FEM model can easily be compared in detail to the holograms. Excellent agreement between the two has been obtained, which is evidence for the validity of the finite element model. The FEM has also been used to explore the effects of changing the shape of the bell. The effects on the overtone structure of changing the bell in some unusual ways will be presented.
Acoustic characteristics of Ekonda scrapers
Authors: Demolin Didier , Weisser Stephanie
Published: October 2013

This paper describes some acoustic characteristics of a musical instrument played with the complex vocal polyphonies of the Ekonda of the Congo. The complexity of these songs and the remarkable pitch accuracy of their intonation are striking given that there is no tuning fork or fixed pitch instrument which can account for the pitch stability. Ekonda scrapers are required to accompany the polyphonies. An acoustic study of these idiophones was made to understand their contributions to the songs. The scrapers are made in a hollow piece of a palm tree branch. The instrument is played by rubbing a piece of hard wood upon splits made on the piece of palm tree. In addition to the friction noise due to the rubbing of the piece of hard wood, there are some very distinct resonances which can be identified. An important observation is that there is always a very intense resonance at the frequency of the musical scales tonic. The relation between the pitch of the tonic and the frequency of the scrapers resonances which act as a tuning fork are detailed.
Development of a model local noise ordinance standard
Authors: Finegold Lawrence S. , Brooks Bennett M.
Published: October 2013

A comprehensive, easy to understand and enforceable local noise ordinance can be a powerful tool in the effort to manage the noise environment at the community level. At the present time, however, many communities do not have a local noise ordinance, and those that do exist can vary considerably. In order to provide guidance to government officials involved in the development of noise ordinances, the American National Standards Institute (ANSI) Standards Committee on Noise (S12), Working Group 41 is developing a Model Local Noise Ordinance. Although this effort is still in the early conceptual stages, this paper will describe some of the issues and approaches that are being considered in the development of this document. It is envisioned that Part 1 of this possible new ANSI Standard will address general community noise control issues that should be considered in the development of a noise ordinance and Part 2 will provide a sample noise ordinance with a menu of standardized language sections that can be selected to fit individual community situations. Ranges of recommended noise exposure criteria will be provided, along with a brief discussion of issues that local officials should consider in choosing these criteria.
Railroads, noise and the city: A manual for authorities
Authors: Elizondo-Garza Fernando J. , Leal-Chapa Cesar A. , Cupich-Rodriguez Miguel , Cupich-Guerrero Jorge
Published: October 2013

Trains crossing cities produce different problems and annoyances; one of them is noise, which directly affects the neighborhoods near the railroad tracks. This situation must be solved jointly by the city authorities and the railroad companies in two ways: planning, which looks to avoid future problems, and short-term solutions, which have the objective to control the present problems. In this paper a manual for authorities is presented that gives an overview of the available options that help in the decision-making process necessary to achieve a problem-free interaction between railroads and cities in relation to noise.
Assessment of adequacy of ray acoustics approach for prediction of barrier insertion loss in the presence of a reflecting ground
Authors: Pazos Daniel F. P. , Musafir Ricardo E. , Avital Eldad J.
Published: October 2013

The precision of insertion loss prediction obtained by applying Kurze–Anderson formula to each of the four possible ray paths connecting source and observer in the presence of a reflecting ground, and computing interference appropriately, is discussed. To this end, the field behind the barrier, given by the method described, is compared to that obtained by solving numerically the continuity and momentum equations simultaneously, using the appropriate boundary conditions to account for the perfectly reflecting ground and the barrier. Analysis of the agreement of the interference patterns obtained in both cases, for pure tones and for octave bands, permits determining the range in which the much simpler ray method provides sufficient results. Calculations with the Kurze–Anderson formula are performed with Mathematica 4.0, while the numerical propagation code is written in Fortran.
Measurement protocol for normalized noise maps
Authors: Viro Gabriel , Ruffa Francisco , Gavinowich Daniel , Bonello Oscar , Ciccarella Pablo , Barkasz Erica
Published: October 2013

As cities grow bigger, traffic noise gets worse. In order to help in the determination of noisy areas, the LACEAC prepared a measurement protocol to aid in this task. This protocol is the base for a recommendation to the cities’ governments. To put together this protocol, the LACEAC has analyzed different legislation together with measurements taken in several pilot areas of the city of Buenos Aires and determined the best approach based on the cultural habits of the city inhabitants. This protocol thus recommends the way that measurement locations should be determined, exposure time, the way to take the measurements, to study the results and to draw the noise maps.
Spectral information in noise-mapping: An exploratory study
Authors: Pasch Vivian , Mosconi Patricia , Yanitelli Marta , Cabanellas Susana , Vazquez Jorge , Rall Juan C. , Miyara Federico
Published: October 2013

International standards such as ISO 1996 and ISO 717 as well as noise regulations in several countries are increasingly relying on spectral information in order to assess the acoustical behavior of materials and structures and the effects of noise on people. Nevertheless, the new European Union Directive on the assessment and management of environmental noise reinforces the A-weighted equivalent level (with appropriate night and evening corrections) as the preferred indicator for noise mapping. Considering that noise maps are a powerful zoning and planning resource, the idea of reporting the mean spectrum of noise at each selected location at different times is proposed and thoroughly justified. Arguments in favor of its feasibility are given, showing that, in spite of the widespread opinion, costs and required time may be reduced considerably by the use of low-priced, new-technology auxiliary equipment. Then an exploratory study is reported, in which (a) the spectrum of traffic noise in Rosario (Argentina) is compared with the internationally standardized traffic noise spectrum, and (b) the noise spectrum at an open street is compared with the noise spectrum at a street with a U-profile owing to the same vehicles.
Evaluation of urban railways noise impact
Authors: Coppi Massimo , Grignaffini Stefano
Published: October 2013

The study of the environmental impact of urban railways mainly regards the noise generated by trains. Italian standards provide for the characterization of territorial pertinence zones (from the outer center line and for each side of the railway tracks), inside which specific absolute limit values of noise introduction produced by the same infrastructure are permitted. Therefore, according to provisions in these areas, the noise evaluation has to be performed referring only to the infrastructure contribution, without evaluating other acoustic sources in the same areas. As a consequence, in the pertinence zones the imposed limits for the infrastructure presence and the limits imposed by the acoustic municipal zoning, taking into account the acoustic impact of the other sources, are valid simultaneously but separately when evaluating the acoustic impact. However, in these areas the general acoustic climate is due to the overlap of both acoustic classes, and the noise induced on the population is determined by the contemporary presence of both sources. It is eventually very important to evaluate the effective noise dose absorbed by the population, especially when having to design mitigation interventions.
Velocity measurements in the acoustic oscillatory boundary layer with laser Doppler anemometry
Authors: Castrejón-Pita J. R. , Castrejón-Pita A. A. , Huelsz G.
Published: October 2013

Velocity measurements using laser Doppler anemometry (LDA) in the oscillatory viscous boundary layer (OVBL) produced by acoustic waves are presented. The amplitude velocity profile of acoustic standing waves in air with frequencies of 68.5, 114.5, and 343.5 Hz are reported. The results agree with the predictions of linear theories and show that the small discrepancies found in similar measurements made with hot wire anemometry (HWA) [Huelsz et al., Exp. Fluids 32, 612 (2002)] are due to the interaction of the hot wire probe with the flow and the wall. The advantages and disadvantages of the LDA technique compared with HWA are discussed for OVBL measurements. [Work supported by CONACyT Project No. 32707-U. The authors wish to thank Guillermo Hernández for his valuable technical support.]
Effective impedance of hard rough surfaces
Authors: Attenborough Keith , Boulanger Patrice
Published: October 2013

The effective impedance of hard rough surfaces insonified from a point source has been investigated through boss models, boundary element simulations, and measurements. The complex excess attenuation measured or predicted has been fitted for effective impedance by means of a formulation for the sound field above a smooth finite impedance plane. It has been found that the effective impedance plane is higher than the nominal one and that the results are very sensitive to the location of the specular reflection point. Polynomial expressions for the real and imaginary parts of the effective impedance have been derived for various types of roughnesses.
Sound propagation in a refracting atmosphere above an impedance discontinuity
Authors: Taherzadeh Shahram , Harrop Nick
Published: October 2013

de Jongs formulation of sound propagation above a ground with a single impedance change has been extended to include effects of a refracting atmosphere and atmospheric turbulence. The theory is compared with a numerical algorithm based on a hybrid Boundary Integral Equation/Fast Field Program developed for predicting the propagation of sound in a refracting atmosphere above an uneven, discontinuous terrain. By using the analogy of sound diffraction over curved surfaces to atmospheric refraction over flat ground surfaces, the effect of temperature and wind velocity gradients in the presence of flat ground surfaces can be studied. Measurements of the excess attenuation of sound from a point source over a mixed impedance curved surface are carried out in an anechoic chamber as well as outdoor measurements over a tarmac–grass discontinuity. These measurements are compared with predictions based on the extended de Jong theory and the hybrid BIE/FFP algorithm in the nonturbulent case. Results show that where there is a single discontinuity between acoustically hard and finite impedance surfaces both models are found to give satisfactory agreement with measured data except when the discontinuity is midway between the source and the detector.
Acoustical measurement system to improve agricultural implements for soil protection
Authors: Martinez Rodolfo , Diego F.
Published: October 2013

This research work is based on theoretical mechanics and agricultural mechanics theory applied to the study of the behavior of animal-pulled implements for seeding or harvesting for minimizing erosion of soil. For this purpose the pertinent acoustic measurements are presented with the objective of finding acoustical parameters useful to evaluate different designs of these kinds of implements with regard to depth and shape of the earth moving device in order to protect agriculture soil from erosion.
A hybrid finite-element formulation for analyzing systems of beams and plates in the midfrequency range
Authors: Hong Sang-Bum , Vlahopoulos Nickolas
Published: October 2013

A hybrid finite-element analysis (hybrid FEA) formulation has been developed in the past for computing the midfrequency vibration of systems that contain one type of energy. The hybrid FEA is based on characterizing as long members in a system all the members that contain a large number of wavelengths within their dimension. All the remaining members are considered as short. The Energy Finite-Element Analysis (EFEA) is employed for modeling the behavior of the long members, while the conventional FEA method is utilized for modeling the short members. In this paper the hybrid FEA formulation is extended to plate structures that are spot-welded to a frame comprised by tubular members. The new formulation is validated by comparing the hybrid FEA solution to results produced by very dense conventional FEA models in the mid-frequency range. [Research supported by the Automotive Research Center, US. Army.]
Petrov–Galerkin’s method hybrid with finite element into the Helmholtz equation solution. Part II
Authors: Rabadan Malda Itzala , Salazar Cordero Emigdio , Ortega Herrera Jose Angel
Published: October 2013

This work proposes a hybridization between Petrov–Galerkins numeric method and finite element method (FEM) to resolve Helmholtz equation when dominion is an open or semiopen tube-shaped configuration and with determinate number of holes over cylindrical surface. It’s pretended to solve these kind of cavities, thereby it allows us to obtain very important design parameters like: cavity length, quantity, size and distance between toneholes, form and size of mouthpiece or outlet. These parameters are design basis into acoustic and musical instrumentation: baffles outlet pipes, diffusers, silencers, flutes, oboes, saxophones, trumpets, quenas, and many more. In this way it’s expected to determine advantages of this numeric method above another using actually.
Nonstationary bifurcations with additive noise
Authors: Davies Huw G.
Published: October 2013

The response of nonlinear systems with slow variation of a parameter through a bifurcation may be critically affected by very-low-level noise. Examples to be discussed include passage through resonance of a periodically pumped laser, a transcritical bifurcation associated with a coupled pitch/roll model of ship motion, and a period-doubling cascade of a discrete map. In each case the original form of the response persists as the control parameter varies through the bifurcation, even though this original form is now unstable. Noise is required to trigger the bifurcated form; then there is a rapid transition with exponential growth from one form of response to another. Sinusoidal parameter variation through the bifurcation at sufficiently high frequency may effectively stabilize the original form by preventing an appreciable growth of the bifurcated form; noise is destabilizing. The two competing effects are analyzed using matched-asymptotic-expansions. The innermost of a nested set of three expansions describes how noise causes the growth of the bifurcating form from the original unstable form. Previous results for period-doubling [H. G. Davies and K. Rangavajhula, Proc R. Soc. London, Ser. A 457, 2965–2982 (2001)] are modified for the other types of bifurcation, and are extended to a higher order period-doubling cascade using renormalization.
Language-specific, hearing-related changes in vowel spaces: A study of English- and Spanish-speaking cochlear implant users
Authors: Perkell Joseph , Polak Marek , Balkany Thomas , Vick Jennell , Lane Harlan , Stockmann Ellen , Tiede Mark , Zandipour Majid
Published: October 2013

This study investigates the role of hearing in vowel productions of postlingually deafened cochlear implant (CI) users. Based on the hypothesis that competing demands of intelligibility and economy of effort influence vowel production, we predicted that speakers of a language with a more crowded vowel space, such as American English, would show an increase in average vowel spacing (AVS the average inter-vowel distance in the F1-F2 plane) with the provision of hearing from a CI; whereas speakers of a language with fewer vowels, such as Spanish, would not. Results of a preliminary on–off study supported the hypothesis: with hearing from a CI, 7 English-speaking CI users all increased AVS; however, among 7 Spanish speakers, some increased AVS and some reduced it. The current study is exploring these findings further with new groups of CI users and normal-hearing speakers of English and Spanish and an elaborated paradigm that includes different speaking rates and comparisons between pre-implant and post-implant recordings. Preliminary results will be reported. [Work supported by NIH.]
Computational models of vowel identification by English- and Spanish-speaking cochlear implant users
Authors: Svirsky Mario A. , Hadley Daniel C. , Neuburger Heidi S. , Teoh Su-Wooi , Villasuso Eloy
Published: October 2013

Cochlear implant (CI) users achieve significant levels of speech recognition on average, but cross-listener variability is very high. Unfortunately, our understanding of the speech perception mechanisms employed by CI users is still incomplete. To address this issue we have developed the multidimensional phoneme identification (MPI) model, which aims to predict phoneme identification for individual cochlear implant users based on their discrimination along specified acoustic dimensions. The MPI model was used to fit vowel confusion matrices from English- and Spanish-speaking CI users. Good agreement between predicted and observed matrices was obtained for both English and Spanish. Some of the acoustic dimensions required to obtain these fits were the same for both languages (e.g., F1 and F2), but others were not (e.g., F3 is required to obtain a good fit in English, but not in Spanish). These results are consistent with differences in the acoustic phonetics of the two languages: a low value of F3 is used in English to encode the retroflex vowel /r/, and this sound does not exist in Spanish. These results raise the possibility that the optimal stimulation strategies may differ across languages. [Work supported by NIDCD (R01-DC03937), NOHR, DRF, and BID/CONICYT (Uruguay).]
Cortical reponses to electrical stimulation from cochlear implants
Authors: Tobey Emily A. , Devous Michael D. , Roland Peter S.
Published: October 2013

In order to examine factors contributing to speech perception performance variations in cochlear implant users, single photon emission computed tomography (SPECT) was used to examine cortical activity elicited by the electrical stimulation of multichannel cochlear implants. Subjects watched a 15-min videotaped story under several conditions: (a) audio presented monaurally in the aided right or left ears; (b) audio presented binaurally with aids; (c) a visual-only presentation; and (d) signals processed through the implant. Five minutes after the start of each story, 99mTc HMPAO was injected over 30 s to insure subjects were unaware of the tracer administration. Right and left monaural stimulation in normal-hearing subjects resulted in significant bilateral activation of Brodmann areas 41, 42, 22, 21, and 38. Despite similar hearing losses to each ear, significant differences in per-operative auditory cortex activation was observed between ears across the subjects. Post-implant, individuals with relatively high levels of open-set speech perception demonstrated bilateral activation of cortex; however, the extent of activation was significantly less than that observed for normal-hearing individuals. Individuals with minimal open-set speech perception scores demonstrated unilateral activation of the cortex on the hemisphere contralateral to the ear of implantation. [Work supported by NIH.]
Rapid inversion of waveguide environmental parameters using an analytic adjoint method
Authors: Thode Aaron
Published: October 2013

A method is presented for inverting sound-speed perturbations in a stratified waveguide environment over several kilometers range. An adjoint Green’s function formalism is used to backpropagate the difference between a measured and modeled received field through the modeled waveguide environment, in a manner reminiscent of acoustic time-reversal methods. Using a set of linearized equations similar in form to the Born approximation, the backpropagated error field is converted into an estimate of an error surface gradient, or Frechet derivative [S. J. Norton, J. Acoust. Soc. Am. 106, 2653–2660]. The gradient can then be used to locate the error surface minimum via a series of iterations. The use of a normal-mode waveguide Green’s function enables a considerable analytic simplification of the equations. The similarities and differences between the adjoint approach, matched-field processing, and diffraction tomography are discussed. [Work sponsored by ONR.]
A 3D forward-look sonar simulation model
Authors: Beaujean Pierre-Philippe J. , Gazagnaire Julia , Cuschieri Joseph M.
Published: October 2013

A modeling tool for 3-D Forward-Look Sonar (3-D-FLS) or equivalent has been developed. The model replicates the entire process of a 3-D Forward-Look sonar generating a 3-D image of a target. The 3-D-FLS operates at a central frequency of 225 kHz and has a range of 100 m. The transmitted signal is a frequency-modulated chirp with 30 kHz of bandwidth. The source is a line array and the projector is a 64-element line array. Ray theory is used to calculate the trajectory of the rays. The model takes sound velocity profiles into account. The reverberation levels due to the sea bottom and sea surface are calculated using Kuos model. Targets of various shapes and sizes are modeled as a collection of reflecting data points. The target strengths of each point on a specific target are assumed equal. The final product is a modeling tool which can be used to define the sonar hardware and processing software necessary to achieve various operational needs. Simulated results are validated using 3-D-FLS data collected during several at-sea experiments.
Buried mine classification by means of higher-order spectral analysis
Authors: Montanari Monica , Schmidt Henrik
Published: October 2013

In the joint MIT/SACLANTCEN Generic Oceanographic Array Technology Sonar (GOATS) project, future missions are envisioned that employ one or more autonomous underwater vehicles (AUVs) for automated target detection and classification. The classification of buried mines after detection is important for reducing the false alarm rate of the mine hunting sonar system. Buried mine classification is pursued in this paper by employing higher-order spectral analysis. Due to the nature of the target, it is expected that there will be at least one elastic response following the specular return from the object. The elastic response is typically of very low signal to noise ratio, and the noise is correlated reverberation, so advanced spectral analysis must be employed to detect the elastic behavior of the target. Higher-order spectral analysis methods are applied to a time signal in a short temporal window following the specular return. The delay of the elastic return corresponds to the time necessary for the wave to travel around the perimeter of the object before it is reradiated toward the receiver. The effectiveness of this approach to mine/rock classification is shown by an application to at-sea data from the GOATS experiment series (1998, 2000, and 2002) as well as advanced acoustic simulations.
Identifying individual sources in matched-field processing by modifying the covariance matrix
Authors: Giddens Eric M. , Roux Philippe , Kuperman W. A.
Published: October 2013

A method for identifying multiple sources in matched-field processing (MFP) is proposed. The ambiguity surface produced by MFP may contain sidelobe structures that confound individual source identification. Data corresponding to the location of the loudest source is added to the signal and the dominant eigenvector of the covariance matrix is removed. The addition of data prevents the degenerate case where a single eigenvector describes multiple sources. The new MFP result has the source and its sidelobes removed from the ambiguity surface. The remaining sources can then be identified. This technique is applied to simulated data as well as Swell-Ex 96 data with a small number of snapshots. [Work supported by ONR.]
Tutorial on architectural acoustics
Authors: Shaw Neil , Talaske Rick , Bistafa Sylvio
Published: October 2013

This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).