Influence of water depth on the sound generated by air-bubble vibration in the water musical instrument

Science.gov (United States)

Ohuchi, Yoshito; Nakazono, Yoichi

2014-06-01

We have developed a water musical instrument that generates sound by the falling of water drops within resonance tubes. The instrument can give people who hear it the healing effect inherent in the sound of water. The sound produced by falling water drops arises from air- bubble vibrations. To investigate the impact of water depth on the air-bubble vibrations, we conducted experiments at varying values of water pressure and nozzle shape. We found that air-bubble vibration frequency does not change at a water depth of 50 mm or greater. Between 35 and 40 mm, however, the frequency decreases. At water depths of 30 mm or below, the air-bubble vibration frequency increases. In our tests, we varied the nozzle diameter from 2 to 4 mm. In addition, we discovered that the time taken for air-bubble vibration to start after the water drops start falling is constant at water depths of 40 mm or greater, but slower at depths below 40 mm.

Sound and sound sources

DEFF Research Database (Denmark)

Larsen, Ole Næsbye; Wahlberg, Magnus

2017-01-01

There is no difference in principle between the infrasonic and ultrasonic sounds, which are inaudible to humans (or other animals) and the sounds that we can hear. In all cases, sound is a wave of pressure and particle oscillations propagating through an elastic medium, such as air. This chapter...... is about the physical laws that govern how animals produce sound signals and how physical principles determine the signals’ frequency content and sound level, the nature of the sound field (sound pressure versus particle vibrations) as well as directional properties of the emitted signal. Many...... of these properties are dictated by simple physical relationships between the size of the sound emitter and the wavelength of emitted sound. The wavelengths of the signals need to be sufficiently short in relation to the size of the emitter to allow for the efficient production of propagating sound pressure waves...

Reversal to air-driven sound production revealed by a molecular phylogeny of tongueless frogs, family Pipidae

Directory of Open Access Journals (Sweden)

Glaw Frank

2011-04-01

Full Text Available Abstract Background Evolutionary novelties often appear by conferring completely new functions to pre-existing structures or by innovating the mechanism through which a particular function is performed. Sound production plays a central role in the behavior of frogs, which use their calls to delimit territories and attract mates. Therefore, frogs have evolved complex vocal structures capable of producing a wide variety of advertising sounds. It is generally acknowledged that most frogs call by moving an air column from the lungs through the glottis with the remarkable exception of the family Pipidae, whose members share a highly specialized sound production mechanism independent of air movement. Results Here, we performed behavioral observations in the poorly known African pipid genus Pseudhymenochirus and document that the sound production in this aquatic frog is almost certainly air-driven. However, morphological comparisons revealed an indisputable pipid nature of Pseudhymenochirus larynx. To place this paradoxical pattern into an evolutionary framework, we reconstructed robust molecular phylogenies of pipids based on complete mitochondrial genomes and nine nuclear protein-coding genes that coincided in placing Pseudhymenochirus nested among other pipids. Conclusions We conclude that although Pseudhymenochirus probably has evolved a reversal to the ancestral non-pipid condition of air-driven sound production, the mechanism through which it occurs is an evolutionary innovation based on the derived larynx of pipids. This strengthens the idea that evolutionary solutions to functional problems often emerge based on previous structures, and for this reason, innovations largely depend on possibilities and constraints predefined by the particular history of each lineage.

Use of Quality Controlled AIRS Temperature Soundings to Improve Forecast Skill

Science.gov (United States)

Susskind, Joel; Reale, Oreste; Iredell, Lena

2010-01-01

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. Also included are the clear column radiances used to derive these products which are representative of the radiances AIRS would have seen if there were no clouds in the field of view. All products also have error estimates. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of 1K, and layer precipitable water with an rms error of 20 percent, in cases with up to 90 percent effective cloud cover. The products are designed for data assimilation purposes for the improvement of numerical weather prediction, as well as for the study of climate and meteorological processes. With regard to data assimilation, one can use either the products themselves or the clear column radiances from which the products were derived. The AIRS Version 5 retrieval algorithm is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates for retrieved quantities and clear column radiances, and the use of these error estimates for Quality Control. The temperature profile error estimates are used to determine a case-by-case characteristic pressure pbest, down to which the profile is considered acceptable for data assimilation purposes. The characteristic pressure p(sub best) is determined by comparing the case dependent error estimate (delta)T(p) to the threshold values (Delta)T(p). The AIRS Version 5 data set provides error estimates of T(p) at all levels, and also profile dependent values of pbest based

Sound absorption and transmission through flexible micro-perforated panels backed by an air layer and a thin plate.

Science.gov (United States)

Bravo, Teresa; Maury, Cédric; Pinhède, Cédric

2012-05-01

This paper describes theoretical and experimental investigations into the sound absorption and transmission properties of micro-perforated panels (MPP) backed by an air cavity and a thin plate. A fully coupled modal approach is proposed to calculate the absorption coefficient and the transmission loss of finite-sized micro-perforated panels-cavity-panel (MPPCP) partitions with conservative boundary conditions. It is validated against infinite partition models and experimental data. A practical methodology is proposed using collocated pressure-velocity sensors to evaluate in an anechoic environment the transmission and absorption properties of conventional MPPCPs. Results show under which conditions edge scattering effects should be accounted for at low frequencies. Coupled mode analysis is also performed and analytical approximations are derived from the resonance frequencies and mode shapes of a flexible MPPCP. It is found that the Helmholtz-type resonance frequency is deduced from the one associated to the rigidly backed MPPCP absorber shifted up by the mass-air mass resonance of the flexible non-perforated double-panel. Moreover, it is shown analytically and experimentally that the absorption mechanisms at the resonances are governed by a large air-frame relative velocity over the MPP surface, with either in-phase or out-of-phase relationships, depending on the MPPCP parameters.

Effect of temporary open-air markets on the sound environment and acoustic perception based on the crowd density characteristics.

Science.gov (United States)

Meng, Qi; Sun, Yang; Kang, Jian

2017-12-01

The sound environment and acoustic perception of open-air markets, which are very common in high-density urban open spaces, play important roles in terms of the urban soundscape. Based on objective and subjective measurements of a typical temporary open-air market in Harbin city, China, the effects of the temporary open-air market on the sound environment and acoustic perception were studied, considering different crowd densities. It was observed that a temporary open-air market without zoning increases the sound pressure level and subjective loudness by 2.4dBA and 0.21dBA, respectively, compared to the absence of a temporary market. Different from the sound pressure level and subjective loudness, the relationship between crowd density and the perceived acoustic comfort is parabolic. Regarding the effect of a temporary open-air market with different zones on the sound environment and acoustic perception, when the crowd densities were the same, subjective loudness in the fruit and vegetable sales area was always higher than in the food sales area and the clothing sales area. In terms of acoustic comfort, with an increase in crowd density, acoustic comfort in the fruit and vegetable sales area decreased, and acoustic comfort in the food sales area and the clothing sales area exhibited a parabolic change trend of increase followed by decrease. Overall, acoustic comfort can be effectively improved by better planning temporary open-air markets in high-density urban open spaces. Copyright © 2017 Elsevier B.V. All rights reserved.

Sound Propagation in Saturated Gas-Vapor-Droplet Suspensions Considering the Effect of Transpiration on Droplet Evaporation

Science.gov (United States)

Kandula, Max

2012-01-01

The Sound attenuation and dispersion in saturated gas-vapor-droplet mixtures with evaporation has been investigated theoretically. The theory is based on an extension of the work of Davidson (1975) to accommodate the effects of transpiration on the linear particle relaxation processes of mass, momentum and energy transfer. It is shown that the inclusion of transpiration in the presence of mass transfer improves the agreement between the theory and the experimental data of Cole and Dobbins (1971) for sound attenuation in air-water fogs at low droplet mass concentrations. The results suggest that transpiration has an appreciable effect on both sound absorption and dispersion for both low and high droplet mass concentrations.

Sound reduction of air compressors using a systematic approach

Science.gov (United States)

Moylan, Justin Tharp

The noise emitted by portable electric air compressors can often be a nuisance or potentially hazardous to the operator or others nearby. Therefore, reducing the noise of these air compressors is desired. This research focuses on compressors with a reciprocating piston design as this is the most common type of pump design for portable compressors. An experimental setup was developed to measure the sound and vibration of the air compressors, including testing inside a semi-anechoic chamber. The design of a quiet air compressor was performed in four stages: 1) Teardown and benchmarking of air compressors, 2) Identification and isolation of noise sources, 3) Development of individual means to quiet noise sources, 4) Selection and testing of integrated solutions. The systematic approach and results for each of these stages will be discussed. Two redesigned solutions were developed and measured to be approximately 65% quieter than the previous unmodified compressor. An additional analysis was performed on the solutions selected by the participants involved in the selection process. This analysis involved determining which of the design criteria each participant considered most important when selecting solutions. The results from each participant were then compared to their educational background and experience and correlations were identified. The correlations discovered suggest that educational background and experience may be key determinants for the preference models developed.

Compressibility, zero sound, and effective mass of a fermionic dipolar gas at finite temperature

International Nuclear Information System (INIS)

Kestner, J. P.; Das Sarma, S.

2010-01-01

The compressibility, zero-sound dispersion, and effective mass of a gas of fermionic dipolar molecules is calculated at finite temperature for one-, two-, and three-dimensional uniform systems, and in a multilayer quasi-two-dimensional system. The compressibility is nonmonotonic in the reduced temperature, T/T F , exhibiting a maximum at finite temperature. This effect might be visible in a quasi-low-dimensional experiment, providing a clear signature of the onset of many-body quantum degeneracy effects. The collective mode dispersion and effective mass show similar nontrivial temperature and density dependence. In a quasi-low-dimensional system, the zero-sound mode may propagate at experimentally attainable temperatures.

The Effective Mass of a Ball in the Air

Science.gov (United States)

Messer, J.; Pantaleone, J.

2010-01-01

The air surrounding a projectile affects the projectile's motion in three very different ways: the drag force, the buoyant force, and the added mass. The added mass is an increase in the projectile's inertia from the motion of the air around it. Here we experimentally measure the added mass of a spherical projectile in air. The results agree well…

Making Sound Connections

Science.gov (United States)

Deal, Walter F., III

2007-01-01

Sound provides and offers amazing insights into the world. Sound waves may be defined as mechanical energy that moves through air or other medium as a longitudinal wave and consists of pressure fluctuations. Humans and animals alike use sound as a means of communication and a tool for survival. Mammals, such as bats, use ultrasonic sound waves to…

Effects of End CAP and Aspect Ratio on Transmission of Sound across a Truss-Like Periodic Double Panel

Science.gov (United States)

EL-RAHEB, M.; WAGNER, P.

2002-02-01

Transmission of sound across 2-D truss-like periodic double panels separated by an air gap and in contact with an acoustic fluid on the external faces is analyzed. Each panel is made of repeated cells. Combining the transfer matrices of the unit cell forms a set of equations for the overall elastic frequency response. The acoustic pressure in the fluids is expressed using a source boundary element method. Adding rigid reflecting end caps confines the air in the gap between panels which influences sound transmission. Measured values of transmission loss differ from the 2-D model by the wide low-frequency dip of the mass-spring-mass or “msm” resonance also termed the “air gap resonance”. In this case, the panels act as rigid masses and the air gap acts as an adiabatic air spring. Results from the idealized 3-D and 2-D models, incorporating rigid cavities and elastic plates, reveal that the “msm” dip is absent in 2-D models radiating into a semi-infinite medium. The dip strengthens as aspect ratio approaches unity. Even when the dip disappears in 2-D, TL rises more steeply for frequencies above the “msm” frequency.

Sound generator

NARCIS (Netherlands)

Berkhoff, Arthur P.

2008-01-01

A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

Sound generator

NARCIS (Netherlands)

Berkhoff, Arthur P.

2010-01-01

A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

Sound generator

NARCIS (Netherlands)

Berkhoff, Arthur P.

2007-01-01

A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

The use of the automation for experiments using computers: determination of sound velocity in air

International Nuclear Information System (INIS)

Valdes, R.; Valdes, P.; Clavelo, A.

1998-01-01

This article shows the use of IBM PCs joysticks in order to measure the speed of sound in the air. Electrical circuits and software are presented and both technical and methodological advantages of the proposed method are discussed. (Author) 19 refs

Sound propagation in narrow tubes including effects of viscothermal and turbulent damping with application to charge air coolers

Science.gov (United States)

Knutsson, Magnus; Åbom, Mats

2009-02-01

Charge air coolers (CACs) are used on turbocharged internal combustion engines to enhance the overall gas-exchange performance. The cooling of the charged air results in higher density and thus volumetric efficiency. It is also important for petrol engines that the knock margin increases with reduced charge air temperature. A property that is still not very well investigated is the sound transmission through a CAC. The losses, due to viscous and thermal boundary layers as well as turbulence, in the narrow cooling tubes result in frequency dependent attenuation of the transmitted sound that is significant and dependent on the flow conditions. Normally, the cross-sections of the cooling tubes are neither circular nor rectangular, which is why no analytical solution accounting for a superimposed mean flow exists. The cross-dimensions of the connecting tanks, located on each side of the cooling tubes, are large compared to the diameters of the inlet and outlet ducts. Three-dimensional effects will therefore be important at frequencies significantly lower than the cut-on frequencies of the inlet/outlet ducts. In this study the two-dimensional finite element solution scheme for sound propagation in narrow tubes, including the effect of viscous and thermal boundary layers, originally derived by Astley and Cummings [Wave propagation in catalytic converters: Formulation of the problem and finite element scheme, Journal of Sound and Vibration 188 (5) (1995) 635-657] is used to extract two-ports to represent the cooling tubes. The approximate solutions for sound propagation, accounting for viscothermal and turbulent boundary layers derived by Dokumaci [Sound transmission in narrow pipes with superimposed uniform mean flow and acoustic modelling of automobile catalytic converters, Journal of Sound and Vibration 182 (5) (1995) 799-808] and Howe [The damping of sound by wall turbulent shear layers, Journal of the Acoustical Society of America 98 (3) (1995) 1723-1730], are

A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

International Nuclear Information System (INIS)

Tao, S.; Liu, Y.N.; Lang, C.; Wang, W.T.; Yuan, H.S.; Zhang, D.Y.; Qiu, W.X.; Liu, J.M.; Liu, Z.G.; Liu, S.Z.; Yi, R.; Ji, M.; Liu, X.X.

2008-01-01

A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test. - A novel directional passive air sampler was developed and tested for monitoring PAHs in air masses from different directions

Comments for the Cape Wind Associates, LLC, Horseshoe Shoal, Nantucket Sound (Offshore Renewable Energy Project/OCS Air Permit)

Science.gov (United States)

List of comments for the Cape Wind Associates, LLC, Horseshoe Shoal, Nantucket Sound (Offshore Renewable Energy Project/OCS Air Permit: Massachusetts Plan Approval including nonattainment NSR Appendix A requirements).

Radon-222 as an indicator of continental air masses and air mass boundaries over ocean areas

International Nuclear Information System (INIS)

Larson, R.E.; Bressan, D.J.

1980-01-01

Radon ( 222 Rn) has proven to be an excellent indicator of the continental nature of over-ocean air and air mass boundaries. Radon is almost exclusively of continental origin, and low-level real-time monitoring is possible with our improved radon measurement techniques. The transition from continental to maritime air in offshore and onshore winds is rather obvious and can easily be established near large islands or continents as an order-of-magnitude change in radon concentration from a few tens of picocuries per cubic meter or more to a few picocuries per cubic meter or less. Sharply changing radon concentrations are usually associated with frontal areas. Our data have offered insights into air movements, and hence transport of continental materials and pollutants over oceanic areas

Comparison between polluted and clean air masses over Lake Michigan

International Nuclear Information System (INIS)

Alkezweeny, A.J.; Laulainen, N.S.

1981-01-01

Clean and polluted air masses, advected over Lake Michigan, were studied using instrumental aircraft during the summers of 1976 and 1978. The results show that regardless of the degree of pollution, the particle size distribution is bimodal. The concentrations of sulfate, nitrate and trace metals in a clean air mass are more than an order of magnitude lower than those in polluted air masses. Furthermore, these concentrations are comparable with those measured in remote areas of the world. In clean air the ratio of the total light scattering to Rayleigh scattering is very close to one, indicating very low concentrations of particulates in the optically active size classes

Measured anisotropic air flow resistivity and sound attenuation of glass wool

DEFF Research Database (Denmark)

Tarnow, Viggo

2002-01-01

Department of Mechanical Engineering, Technical University of Denmark, Bygning 358, DK 2800 Lyngby, Denmark The air flow resistivity of glass wool has been measured in different directions. The glass wool was delivered from the manufacturer as slabs measuring 100×600×900 mm3, where the surface 600...... 7.75 kPa s m**2. A formula for prediction of resistivity for other densities is given. By comparing measured values of sound attenuation with results calculated from resistivity data, it is demonstrated that the measured attenuation can be predicted in a simple manner. ©2002 Acoustical Society...

Normal Incidence of Sound Transmission Loss of a Double-Leaf Partition Inserted with a Microperforated Panel

Directory of Open Access Journals (Sweden)

A. Putra

2013-01-01

Full Text Available A double-leaf partition in engineering structures has been widely applied for its advantages, that is, in terms of its mechanical strength as well as its lightweight property. In noise control, the double-leaf also serves as an effective noise barrier. Unfortunately at low frequency, the sound transmission loss reduces significantly due to the coupling between the panels and the air between them. This paper studies the effect of a microperforated panel (MPP inserted inside a double-leaf partition on the sound transmission loss performance of the system. The MPP insertion is proposed to provide a hygienic double-leaf noise insulator replacing the classical abrasive porous materials between the panels. It is found that the transmission loss improves at the troublesome mass-air-mass resonant frequency if the MPP is located closer to the solid panel. The mathematical model is derived for normal incidence of acoustic loading.

Improving Forecast Skill by Assimilation of Quality Controlled AIRS Version 5 Temperature Soundings

Science.gov (United States)

Susskind, Joel; Reale, Oreste

2009-01-01

The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of cloud cleared radiances R(sub i). This approach allows for the generation of accurate values of R(sub i) and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel error estimates for R(sub i). These error estimates are used for Quality Control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of Quality Control using the NASA GEOS-5 data assimilation system. Assimilation of Quality Controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done operationally by ECMWF and NCEP. Forecast resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

Simulation of Sound Waves Using the Lattice Boltzmann Method for Fluid Flow: Benchmark Cases for Outdoor Sound Propagation.

Science.gov (United States)

Salomons, Erik M; Lohman, Walter J A; Zhou, Han

2016-01-01

Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM) for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases: free-field propagation, propagation over porous and non-porous ground, propagation over a noise barrier, and propagation in an atmosphere with wind. LBM results are compared with solutions of the equations of acoustics. It is found that the LBM works well for sound waves, but dissipation of sound waves with the LBM is generally much larger than real dissipation of sound waves in air. To circumvent this problem it is proposed here to use the LBM for assessing the excess sound level, i.e. the difference between the sound level and the free-field sound level. The effect of dissipation on the excess sound level is much smaller than the effect on the sound level, so the LBM can be used to estimate the excess sound level for a non-dissipative atmosphere, which is a useful quantity in atmospheric acoustics. To reduce dissipation in an LBM simulation two approaches are considered: i) reduction of the kinematic viscosity and ii) reduction of the lattice spacing.

Sound-proof Sandwich Panel Design via Metamaterial Concept

Science.gov (United States)

Sui, Ni

the core material maintains the mechanical property and yields a sound transmission loss that is consistently greater than 50 dB at low frequencies. Furthermore, the absorption property of the proposed honeycomb sandwich panel was experimentally studied. The honeycomb sandwich panel shows an excellent sound absorbing performance at high frequencies by using reinforced glass fiber without adding too much mass. The effect of the panel size and the stiffness of the grid-like frame effect of the honeycomb sandwich structures on sound transmission are discussed lastly. For the second sound-proof sandwich panel design, each unit cell of the sandwich panel is replaced by a Helmholtz resonator by perforating a small hole on the top face sheet. A perfect sound absorber sandwich panel with coupled Helmholtz resonators is proposed by two types: single identical Helmholtz resonator in each unit cell and dual Helmholtz resonators with different orifices, arranged in each cell arranged periodically. The soundproof sandwich panel is modelled as a panel embedded in rigid panel and assumed as a semiinfinite space with hard boundary condition. The net/mutual impedance model is first proposed and derived by solving Kirchhoff-Helmholtz integral by using the Green's function. The thermal-viscous energy dissipation at the thermal boundary layer dominates the total energy consumed. Two types of perfect sound absorber sandwich panel are designed in the last part. Two theoretical methods: the average energy and the equivalent surface impedance method are used to predict sound absorption performance. The geometry for perfect sound absorber sandwich panel at a target frequency can be obtained when the all the Helmholtz resonators are at resonance and the surface impedance of the sandwich panel matches the air impedance. The bandwidth for the identical sandwich panel mainly depends on the neck radius. The absorptive property of the dual Helmholtz resonators type of sandwich panel is studied by

The effect of isotopic mass on the velocity of sound in liquid Li

International Nuclear Information System (INIS)

McAlister, S.P.; Crozier, E.D.; Cochran, J.F.

1976-01-01

Results are presented for the velocity of ultrasound in liquid 6 Li- 7 Li alloys of composition 4.5, 49.7 and 99.9 at % Li for temperatures up to 700 0 C. At the melting point the ratio of the velocity of sound in 6 Li to that in 7 Li was found within experimental error to equal (M 7 /M 6 )sup(1/2), the result expected for classical liquids which differ only in the isotopic mass M. In the alloy of 49.7 at % 7 Li the sound velocity exceeded by 0.6% the value expected for a thermodynamically ideal alloy. This result is discussed in terms of the theoretical treatment by Parrinello et al, (J. Phys. C.: Solid St. Phys.; 7:2577 (1974)) of collective excitations in binary isotopic fluids. (author)

An Undergraduate Experiment for the Measurement of the Speed of Sound in Air: Phenomena and Discussion

Science.gov (United States)

Yang, Hujiang; Zhao, Xiaohong; Wang, Xin; Xiao, Jinghua

2012-01-01

In this paper, we present and discuss some phenomena in an undergraduate experiment for the measurement of the speed of sound in air. A square wave distorts when connected to a piezoelectric transducer. Moreover, the amplitude of the receiving signal varies with the driving frequency. Comparing with the Gibbs phenomenon, these phenomena can be…

Compressed air noise reductions from using advanced air gun nozzles in research and development environments.

Science.gov (United States)

Prieve, Kurt; Rice, Amanda; Raynor, Peter C

2017-08-01

The aims of this study were to evaluate sound levels produced by compressed air guns in research and development (R&D) environments, replace conventional air gun models with advanced noise-reducing air nozzles, and measure changes in sound levels to assess the effectiveness of the advanced nozzles as engineering controls for noise. Ten different R&D manufacturing areas that used compressed air guns were identified and included in the study. A-weighted sound level and Z-weighted octave band measurements were taken simultaneously using a single instrument. In each area, three sets of measurements, each lasting for 20 sec, were taken 1 m away and perpendicular to the air stream of the conventional air gun while a worker simulated typical air gun work use. Two different advanced noise-reducing air nozzles were then installed. Sound level and octave band data were collected for each of these nozzles using the same methods as for the original air guns. Both of the advanced nozzles provided sound level reductions of about 7 dBA, on average. The highest noise reductions measured were 17.2 dBA for one model and 17.7 dBA for the other. In two areas, the advanced nozzles yielded no sound level reduction, or they produced small increases in sound level. The octave band data showed strong similarities in sound level among all air gun nozzles within the 10-1,000 Hz frequency range. However, the advanced air nozzles generally had lower noise contributions in the 1,000-20,000 Hz range. The observed decreases at these higher frequencies caused the overall sound level reductions that were measured. Installing new advanced noise-reducing air nozzles can provide large sound level reductions in comparison to existing conventional nozzles, which has direct benefit for hearing conservation efforts.

Simulation of sound waves using the Lattice Boltzmann Method for fluid flow: Benchmark cases for outdoor sound propagation

NARCIS (Netherlands)

Salomons, E.M.; Lohman, W.J.A.; Zhou, H.

2016-01-01

Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM) for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases:

The use of acoustically tuned resonators to improve the sound transmission loss of double panel partitions

Science.gov (United States)

Mason, J. M.; Fahy, F. J.

1986-10-01

The effectiveness of tuned Helmholtz resonators connected to the partition cavity in double-leaf partitions utilized in situations requiring low weight structures with high transmission loss is investigated as a method of improving sound transmission loss. This is demonstrated by a simple theoretical model and then experimentally verified. Results show that substantial improvements may be obtained at and around the mass-air-mass frequency for a total resonator volume 15 percent of the cavity volume.

Memory for product sounds: the effect of sound and label type.

Science.gov (United States)

Ozcan, Elif; van Egmond, René

2007-11-01

The (mnemonic) interactions between auditory, visual, and the semantic systems have been investigated using structurally complex auditory stimuli (i.e., product sounds). Six types of product sounds (air, alarm, cyclic, impact, liquid, mechanical) that vary in spectral-temporal structure were presented in four label type conditions: self-generated text, text, image, and pictogram. A memory paradigm that incorporated free recall, recognition, and matching tasks was employed. The results for the sound type suggest that the amount of spectral-temporal structure in a sound can be indicative for memory performance. Findings related to label type suggest that 'self' creates a strong bias for the retrieval and the recognition of sounds that were self-labeled; the density and the complexity of the visual information (i.e., pictograms) hinders the memory performance ('visual' overshadowing effect); and image labeling has an additive effect on the recall and matching tasks (dual coding). Thus, the findings suggest that the memory performances for product sounds are task-dependent.

General analytical approach for sound transmission loss analysis through a thick metamaterial plate

International Nuclear Information System (INIS)

Oudich, Mourad; Zhou, Xiaoming; Badreddine Assouar, M.

2014-01-01

We report theoretically and numerically on the sound transmission loss performance through a thick plate-type acoustic metamaterial made of spring-mass resonators attached to the surface of a homogeneous elastic plate. Two general analytical approaches based on plane wave expansion were developed to calculate both the sound transmission loss through the metamaterial plate (thick and thin) and its band structure. The first one can be applied to thick plate systems to study the sound transmission for any normal or oblique incident sound pressure. The second approach gives the metamaterial dispersion behavior to describe the vibrational motions of the plate, which helps to understand the physics behind sound radiation through air by the structure. Computed results show that high sound transmission loss up to 72 dB at 2 kHz is reached with a thick metamaterial plate while only 23 dB can be obtained for a simple homogeneous plate with the same thickness. Such plate-type acoustic metamaterial can be a very effective solution for high performance sound insulation and structural vibration shielding in the very low-frequency range

General analytical approach for sound transmission loss analysis through a thick metamaterial plate

Energy Technology Data Exchange (ETDEWEB)

Oudich, Mourad; Zhou, Xiaoming; Badreddine Assouar, M., E-mail: Badreddine.Assouar@univ-lorraine.fr [CNRS, Institut Jean Lamour, Vandoeuvre-lès-Nancy F-54506 (France); Institut Jean Lamour, University of Lorraine, Boulevard des Aiguillettes, BP: 70239, 54506 Vandoeuvre-lès-Nancy (France)

2014-11-21

We report theoretically and numerically on the sound transmission loss performance through a thick plate-type acoustic metamaterial made of spring-mass resonators attached to the surface of a homogeneous elastic plate. Two general analytical approaches based on plane wave expansion were developed to calculate both the sound transmission loss through the metamaterial plate (thick and thin) and its band structure. The first one can be applied to thick plate systems to study the sound transmission for any normal or oblique incident sound pressure. The second approach gives the metamaterial dispersion behavior to describe the vibrational motions of the plate, which helps to understand the physics behind sound radiation through air by the structure. Computed results show that high sound transmission loss up to 72 dB at 2 kHz is reached with a thick metamaterial plate while only 23 dB can be obtained for a simple homogeneous plate with the same thickness. Such plate-type acoustic metamaterial can be a very effective solution for high performance sound insulation and structural vibration shielding in the very low-frequency range.

SOUND TRANSMISSION LOSS OF A DOUBLE-LEAF PARTITION WITH MICRO-PERFORATED PLATE INSERTION UNDER DIFFUSE FIELD INCIDENCE

Directory of Open Access Journals (Sweden)

A. Putra

2013-06-01

Full Text Available In noise control applications, a double-leaf partition has been applied widely as a lightweight structure for noise insulation, such as in car doors, train bodies, and aircraft fuselages. Unfortunately, the insulation performance deteriorates significantly at mass-air-mass resonance due to coupling between the panels and the air in the gap. This paper investigates the effect of a micro-perforated panel (MPP, inserted in the conventional double-panel partition, on sound transmission loss at troublesome resonant frequencies. It is found that the transmission loss improves at this resonance if the MPP is located at a distance of less than half that of the air gap. A mathematical model is derived for the diffuse field incidence of acoustic loading.

Air Mass Origin in the Arctic and its Response to Future Warming

Science.gov (United States)

Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

2014-01-01

We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

Air temperature measurements based on the speed of sound to compensate long distance interferometric measurements

Directory of Open Access Journals (Sweden)

Astrua Milena

2014-01-01

Full Text Available A method to measure the real time temperature distribution along an interferometer path based on the propagation of acoustic waves is presented. It exploits the high sensitivity of the speed of sound in air to the air temperature. In particular, it takes advantage of a special set-up where the generation of the acoustic waves is synchronous with the amplitude modulation of a laser source. A photodetector converts the laser light to an electronic signal considered as reference, while the incoming acoustic waves are focused on a microphone and generate a second signal. In this condition, the phase difference between the two signals substantially depends on the temperature of the air volume interposed between the sources and the receivers. The comparison with the traditional temperature sensors highlighted the limit of the latter in case of fast temperature variations and the advantage of a measurement integrated along the optical path instead of a sampling measurement. The capability of the acoustic method to compensate the interferometric distance measurements due to air temperature variations has been demonstrated for distances up to 27 m.

The velocity of sound

International Nuclear Information System (INIS)

Beyer, R.T.

1985-01-01

The paper reviews the work carried out on the velocity of sound in liquid alkali metals. The experimental methods to determine the velocity measurements are described. Tables are presented of reported data on the velocity of sound in lithium, sodium, potassium, rubidium and caesium. A formula is given for alkali metals, in which the sound velocity is a function of shear viscosity, atomic mass and atomic volume. (U.K.)

Acoustic metacages for sound shielding with steady air flow

Science.gov (United States)

Shen, Chen; Xie, Yangbo; Li, Junfei; Cummer, Steven A.; Jing, Yun

2018-03-01

Conventional sound shielding structures typically prevent fluid transport between the exterior and interior. A design of a two-dimensional acoustic metacage with subwavelength thickness which can shield acoustic waves from all directions while allowing steady fluid flow is presented in this paper. The structure is designed based on acoustic gradient-index metasurfaces composed of open channels and shunted Helmholtz resonators. In-plane sound at an arbitrary angle of incidence is reflected due to the strong parallel momentum on the metacage surface, which leads to low sound transmission through the metacage. The performance of the proposed metacage is verified by numerical simulations and measurements on a three-dimensional printed prototype. The acoustic metacage has potential applications in sound insulation where steady fluid flow is necessary or advantageous.

Device for measuring mass of air. Einrichtung zur Luftmassenmessung

Energy Technology Data Exchange (ETDEWEB)

Sass, W

1989-09-28

In a device for measuring the mass of air, particularly for vehicles with internal combustion engines, with a measurement bridge, in one branch of which an air flow resistance, particularly a hot film sensor, which has air flowing round it, is connected in series with a measuring resistance and in another branch of which a compensation resistance measuring the air temperature is connected in series with a fixed resistor, where the bridge differential voltage is measured in the zero branch of the measuring bridge and the resulting signal is used to control a transistor valve situated in the bridge supply path of a bridge supply source with an emitter connected to the bridge via the transistor base for bridge compensation and where the voltage at the measurement resistance after bridge compensation is evaluated as a measure of the air flow, the invention proposes that the transistor valve should be made as an npn transistor blocking for negative voltage peaks in the bridge supply path. This ensures that for netgative voltage peaks in the supply line, the transistor valve closes temporarily and overheating of the measurement bridge is prevented. Such overheating would lead to measurement of too great air mass flow and therefore to a dangerously too rich fuel/air mixture, for example (instead the negative voltage peaks give a safe temporary lean mixture).

The fabrication of plastic cages for suspension in mass air flow racks.

Science.gov (United States)

Nielsen, F H; Bailey, B

1979-08-01

A cage for suspension in mass air flow racks was constructed of plastic and used to house rats. Little or no difficulty was encountered with the mass air flow rack-suspended cage system during the 4 years it was used for the study of trace elements.

Pacific and Atlantic herring produce burst pulse sounds.

Science.gov (United States)

Wilson, Ben; Batty, Robert S; Dill, Lawrence M

2004-02-07

The commercial importance of Pacific and Atlantic herring (Clupea pallasii and Clupea harengus) has ensured that much of their biology has received attention. However, their sound production remains poorly studied. We describe the sounds made by captive wild-caught herring. Pacific herring produce distinctive bursts of pulses, termed Fast Repetitive Tick (FRT) sounds. These trains of broadband pulses (1.7-22 kHz) lasted between 0.6 s and 7.6 s. Most were produced at night; feeding regime did not affect their frequency, and fish produced FRT sounds without direct access to the air. Digestive gas or gulped air transfer to the swim bladder, therefore, do not appear to be responsible for FRT sound generation. Atlantic herring also produce FRT sounds, and video analysis showed an association with bubble expulsion from the anal duct region (i.e. from the gut or swim bladder). To the best of the authors' knowledge, sound production by such means has not previously been described. The function(s) of these sounds are unknown, but as the per capita rates of sound production by fish at higher densities were greater, social mediation appears likely. These sounds may have consequences for our understanding of herring behaviour and the effects of noise pollution.

Sonotropic effects of commercial air transport sound on birds.

Science.gov (United States)

1962-03-01

The Electra sound spectrum contains an audible chirp which appears identical in frequency and wave form to the chirp of field crickets. Field observations strongly indicate the sound of the taxiing Electra exerts an attraction for starlings, and poss...

Landscape seasons and air mass dynamics in Latvia

International Nuclear Information System (INIS)

Krauklis, A.; Draveniece, A.

2004-01-01

Latvia is located in the middle of an area where the boreal and nemoral zones and the regions of oceanic and continental climate meet, and it was studied as a model territory of the most typical variation of boreo-nemoral ecotone. The subject of this study was seasonal dynamics of the state of landscapes and diachronous links between seasons. It was found that landscapes undergo 12 seasonal states or seasons during the annual cycle of insulation and air mass occurrence. Each season may be distinguished by a definite amount of solar radiation, distinctive state of heat and water balance, phenological state of vegetation, and a distinctive occurrence of different air mass types and their particular 'association'. During each season these variables show a particular combination of numerical values and a distinctive landscape pattern

Sound Velocity in Soap Foams

International Nuclear Information System (INIS)

Wu Gong-Tao; Lü Yong-Jun; Liu Peng-Fei; Li Yi-Ning; Shi Qing-Fan

2012-01-01

The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration

Ultra-thin smart acoustic metasurface for low-frequency sound insulation

Science.gov (United States)

Zhang, Hao; Xiao, Yong; Wen, Jihong; Yu, Dianlong; Wen, Xisen

2016-04-01

Insulating low-frequency sound is a conventional challenge due to the high areal mass required by mass law. In this letter, we propose a smart acoustic metasurface consisting of an ultra-thin aluminum foil bonded with piezoelectric resonators. Numerical and experimental results show that the metasurface can break the conventional mass law of sound insulation by 30 dB in the low frequency regime (sound insulation performance is attributed to the infinite effective dynamic mass density produced by the smart resonators. It is also demonstrated that the excellent sound insulation property can be conveniently tuned by simply adjusting the external circuits instead of modifying the structure of the metasurface.

Total reflection x-ray fluorescence (TXRF) - a tool to obtain information about different air masses and air pollution

International Nuclear Information System (INIS)

Schmeling, M.

2000-01-01

Aerosols are solid particles dissolved in the atmosphere and have strong influence in the earth climate. Their solid surfaces are the only atmospheric medium for condensation of water leading to cloud formation and ultimately to precipitation. Besides their role in cloud formation, the elemental composition of aerosols reveals useful information about air masses and their transport patterns as well as air pollution. The elemental composition can be considered like a fingerprint of an air mass telling the story about its origin and fate. The presence of Al, Ti and Fe for instance indicates a source located in a highly exposed soil or often desert region, whereas Ni, V and Pb can be traced back to anthropogenic activities like fuel combustion or industrial processes. Other important source regions are the oceans, which emit the main aerosol constituents Na, Cl, and S. The concentrations of these elements in the atmosphere are extremely low and long sampling times are necessary to gain reliable results with most of the common analysis techniques. In contrast to this total reflection x-ray fluorescence (TXRF), as a technique capable to cope with tiny sample amounts, offers the unique possibility to reduce collection times to a minimum of minutes to hours. Such short sampling times in turn render it possible to monitor different air masses either passing through a ground based station or -in the ideal case- flown into by a small research aircraft. Different aerosol samples were taken by aircraft during the second aerosol characterization experiment (ACE-2) with sampling times ranging from 15 minutes up to one hour. These filter samples were analyzed by TXRF for trace elements subsequently. Together with background information about back trajectories and size distribution covering the time of sampling the presence of different air masses could be detected. In another project, short-term samples in the Chicago/Lake Michigan area are collected to study the air mass

The influence of surface treatment on mass transfer between air and building material

DEFF Research Database (Denmark)

Kwiatkowski, Jerzy; Rode, Carsten; Hansen, Kurt Kielsgaard

2008-01-01

for the experiments: gypsum board and calcium silicate. The wallpaper and paint were used as finishing materials. Impact of the following parameters for changes of RH was studied: coating, temperature and air movement. The measurements showed that acryl paint (diffusion open) can significantly decrease mass uptake......The processes of mass transfer between air and building structure and in the material influence not only the conditions within the material but also inside the connected air spaces. The material which absorbs and desorbs water vapour can be used to moderate the amplitude of indoor relative humidity...... and therefore to participate in the improvement of the indoor air quality and energy saving. Many parameters influence water vapour exchange between indoor air and building material. The aim of this work is to present the change of mass transfer under different climatic and material conditions. The measurements...

Water vapor mass balance method for determining air infiltration rates in houses

Science.gov (United States)

David R. DeWalle; Gordon M. Heisler

1980-01-01

A water vapor mass balance technique that includes the use of common humidity-control equipment can be used to determine average air infiltration rates in buildings. Only measurements of the humidity inside and outside the home, the mass of vapor exchanged by a humidifier/dehumidifier, and the volume of interior air space are needed. This method gives results that...

Air mass origins influencing TTL chemical composition over West Africa during 2006 summer monsoon

Directory of Open Access Journals (Sweden)

K. S. Law

2010-11-01

Full Text Available Trace gas and aerosol data collected in the tropical tropopause layer (TTL between 12–18.5 km by the M55 Geophysica aircraft as part of the SCOUT-AMMA campaign over West Africa during the summer monsoon in August 2006 have been analysed in terms of their air mass origins. Analysis of domain filling back trajectories arriving over West Africa, and in the specific region of the flights, showed that the M55 flights were generally representative of air masses arriving over West Africa during the first 2 weeks of August, 2006. Air originating from the mid-latitude lower stratosphere was under-sampled (in the mid-upper TTL whilst air masses uplifted from central Africa (into the lower TTL were over-sampled in the latter part of the campaign. Signatures of recent (previous 10 days origins were superimposed on the large-scale westward flow over West Africa. In the lower TTL, air masses were impacted by recent local deep convection over Africa at the level of main convective outflow (350 K, 200 hPa and on certain days up to 370 K (100 hPa. Estimates of the fraction of air masses influenced by local convection vary from 10 to 50% depending on the method applied and from day to day during the campaign. The analysis shows that flights on 7, 8 and 11 August were more influenced by local convection than on 4 and 13 August allowing separation of trace gas and aerosol measurements into "convective" and "non-convective" flights. Strong signatures, particularly in species with short lifetimes (relative to CO₂ like CO, NO and fine-mode aerosols were seen during flights most influenced by convection up to 350–365 K. Observed profiles were also constantly perturbed by uplift (as high as 39% of air masses from the mid to lower troposphere over Asia, India, and oceanic regions resulting in import of clean oceanic (e.g. O₃-poor or polluted air masses from Asia (high O₃, CO, CO₂ into West Africa. Thus, recent uplift of CO

Vibrometry Assessment of the External Thermal Composite Insulation Systems Influence on the Façade Airborne Sound Insulation

Directory of Open Access Journals (Sweden)

Daniel Urbán

2018-05-01

Full Text Available This paper verifies the impact of the use of an external thermal composite system (ETICS on air-borne sound insulation. For optimum accuracy over a wide frequency range, classical microphone based transmission measurements are combined with accelerometer based vibrometry measurements. Consistency is found between structural resonance frequencies and bending wave velocity dispersion curves determined by vibrometry on the one hand and spectral features of the sound reduction index, the ETICS mass-spring-mass resonance induced dip in the acoustic insulation spectrum, and the coincidence induced dip on the other hand. Scanning vibrometry proves to be an effective tool for structural assessment in the design phase of ETICS systems. The measured spectra are obtained with high resolution in wide frequency range, and yield sound insulation values are not affected by the room acoustic features of the laboratory transmission rooms. The complementarity between the microphone and accelerometer based results allows assessing the effect of ETICS on the sound insulation spectrum in an extended frequency range from 20 Hz to 10 kHz. The modified engineering ΔR prediction model for frequency range up to coincidence frequency of external plaster layer is recommended. Values for the sound reduction index obtained by a modified prediction method are consistent with the measured data.

Dusty air masses transport between Amazon Basin and Caribbean Islands

Science.gov (United States)

Euphrasie-Clotilde, Lovely; Molinie, Jack; Prospero, Joseph; Feuillard, Tony; Brute, Francenor; Jeannot, Alexis

2015-04-01

Depend on the month, African desert dust affect different parts of the North Atlantic Ocean. From December to April, Saharan dust outbreaks are often reported over the amazon basin and from May to November over the Caribbean islands and the southern regions of USA. This annual oscillation of Saharan dust presence, related to the ITCZ position, is perturbed some time, during March. Indeed, over Guadeloupe, the air quality network observed between 2007 and 2012 several dust events during March. In this paper, using HISPLIT back trajectories, we analyzed air masses trajectories for March dust events observed in Guadeloupe, from 2007 to 2012.We observed that the high pressure positions over the Atlantic Ocean allow the transport of dusty air masses from southern region of West Africa to the Caribbean Sea with a path crossing close to coastal region of French Guyana. Complementary investigations including the relationship between PM10 concentrations recorded in two sites Pointe-a-Pitre in the Caribbean, and Cayenne in French Guyana, have been done. Moreover we focus on the mean delay observed between the times arrival. All the results show a link between pathway of dusty air masses present over amazon basin and over the Caribbean region during several event of March. The next step will be the comparison of mineral dust composition for this particular month.

Influence of the relative optical air mass on ultraviolet erythemal irradiance

Science.gov (United States)

Antón, M.; Serrano, A.; Cancillo, M. L.; García, J. A.

2009-12-01

The main objective of this article is to analyze the relationship between the transmissivity for ultraviolet erythemal irradiance (UVER) and the relative optical air mass at Badajoz (Southwestern Spain). Thus, a power expression between both variables is developed, which analyses in detail how atmospheric transmission is influenced by the total ozone column (TOC) and the atmospheric clearness. The period of analysis extends from 2001 to 2005. The experimental results indicate that clearness conditions play an important role in the relationship between UVER transmissivity and the relative optical air mass, while the effect of TOC is much smaller for this data set. In addition, the results show that UVER transmissivity is more sensitive to changes in atmospheric clearness than to TOC variability. Changes in TOC values higher than 15% cause UVER trasnmissivity to vary between 14% and 22%, while changes between cloud-free and overcast conditions produce variations in UVER transmissivity between 68% and 74% depending on the relative optical air mass.

Defining Winter and Identifying Synoptic Air Mass Change in the Northeast and Northern Plains U.S. since 1950

Science.gov (United States)

Chapman, C. J.; Pennington, D.; Beitscher, M. R.; Godek, M. L.

2017-12-01

Understanding and forecasting the characteristics of winter weather change in the northern U.S. is vital to regional economy, agriculture, tourism and resident life. This is especially true in the Northeast and Northern Plains where substantial changes to the winter season have already been documented in the atmospheric science and biological literature. As there is no single established definition of `winter', this research attempts to identify the winter season in both regions utilizing a synoptic climatological approach with air mass frequencies. The Spatial Synoptic Classification is used to determine the daily air mass/ weather type conditions since 1950 at 40 locations across the two regions. Annual frequencies are first computed as a baseline reference. Then winter air mass frequencies and departures from normal are calculated to define the season along with the statistical significance. Once the synoptic winter is established, long-term regional changes to the season and significance are explored. As evident global changes have occurred after 1975, an Early period of years prior to 1975 and a Late set for all years following this date are compared. Early and Late record synoptic changes are then examined to assess any thermal and moisture condition changes of the regional winter air masses over time. Cold to moderately dry air masses dominate annually in both regions. Northeast winters are also characterized by cold to moderate dry air masses, with coastal locations experiencing more Moist Polar types. The Northern Plains winters are dominated by cold, dry air masses in the east and cold to moderate dry air masses in the west. Prior to 1975, Northeast winters are defined by an increase in cooler and wetter air masses. Dry Tropical air masses only occur in this region after 1975. Northern Plains winters are also characterized by more cold, dry air masses prior to 1975. More Dry Moderate and Moist Moderate air masses have occurred since 1975. These results

The time series variations of tritium concentration in precipitation and its relationships to the rainfall-inducing air mass

International Nuclear Information System (INIS)

Shimada, Jun

1978-01-01

The author measured the tritium concentration in precipitation of Tokyo for every ten-day period from August 1972 to May 1974. Judging from the daily synoptic weather chart, the rainfall-inducing air masses in Japan were classified into five types; polar maritime air mass (Pm), polar continental air mass (Pc), tropical maritime air mass (Tm), tropical continental air mass (Tc), and equatorial maritime air mass (Em). And the precipitation for every ten-day period sampled for tritium measurement were classified into these five types. Based on this classification, it is confirmed that there exist clear difference in the tritium concentration between the rainfall from the continental air mass and ones from the maritime air mass. It is characteristic that the tritium concentration in rainfall induced by equatorial maritime air mass such as typhoon in summer and early fall season is very low whereas the tritium concentration in rainfall and snowfall induced directly by the polar continental air mass in late winter season is very high. The regional difference of the tritium concentration in intermonthly precipitation could considerably be explained by this synoptic meteological classification of rainfall-inducing air mass. In spite of these regional difference of tritium concentration in precipitation, use of the tritium concentration of Tokyo as a representative value of Japan may be allowed because of the similarities of the changing pattern and annual mean tritium concentration. The time series variations of tritium concentration in precipitation of Tokyo from August 1972 to December 1977, Tsukuba from December 1976 to April 1978, and Nagaoka from April 1977 to March 1978 are listed. (author)

Sound Levels in East Texas Schools.

Science.gov (United States)

Turner, Aaron Lynn

A survey of sound levels was taken in several Texas schools to determine the amount of noise and sound present by size of class, type of activity, location of building, and the presence of air conditioning and large amounts of glass. The data indicate that class size and relative amounts of glass have no significant bearing on the production of…

On the Influence of Air Mass Origin on Low-Cloud Properties in the Southeast Atlantic

Science.gov (United States)

Fuchs, Julia; Cermak, Jan; Andersen, Hendrik; Hollmann, Rainer; Schwarz, Katharina

2017-10-01

This study investigates the impact of air mass origin and dynamics on cloud property changes in the Southeast Atlantic (SEA) during the biomass burning season. The understanding of clouds and their determinants at different scales is important for constraining the Earth's radiative budget and thus prominent in climate system research. In this study, the thermodynamically stable SEA stratocumulus cover is observed not only as the result of local environmental conditions but also as connected to large-scale meteorology by the often neglected but important role of spatial origins of air masses entering this region. In order to assess to what extent cloud properties are impacted by aerosol concentration, air mass history, and meteorology, a Hybrid Single-Particle Lagrangian Integrated Trajectory cluster analysis is conducted linking satellite observations of cloud properties (Spinning-Enhanced Visible and Infrared Imager), information on aerosol species (Monitoring Atmospheric Composition and Climate), and meteorological context (ERA-Interim reanalysis) to air mass clusters. It is found that a characteristic pattern of air mass origins connected to distinct synoptical conditions leads to marked cloud property changes in the southern part of the study area. Long-distance air masses are related to midlatitude weather disturbances that affect the cloud microphysics, especially in the southwestern subdomain of the study area. Changes in cloud effective radius are consistent with a boundary layer deepening and changes in lower tropospheric stability (LTS). In the southeastern subdomain cloud cover is controlled by a generally higher LTS, while air mass origin plays a minor role. This study leads to a better understanding of the dynamical drivers behind observed stratocumulus cloud properties in the SEA and frames potentially interesting conditions for aerosol-cloud interactions.

Study on heat and mass transfer characteristics of humid air-flow in a fin bundle

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong-Hwi [Air-Conditioner Research Laboratory, LG Electronics, Seoul 153-082 (Korea); Koyama, Shigeru; Kuwahara, Ken [Department of Energy and Environmental Engineering, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Kwon, Jeong-Tae [Department of Mechanical Engineering, Hoseo University, Asan, Chungnam 336-795 (Korea); Park, Byung-Duck [School of Mechanical and Automotive Engineering, Kyungpook National University, Sangju, Gyeongbuk 742-711 (Korea)

2010-11-15

This paper deals with the heat and mass transfer characteristics of humid air-flow under frosting conditions. A slit fin bundle was used for the simulation of fins of a heat exchanger. The effects of the cooling block temperature, air humidity and air velocity on the frosting characteristics were experimentally investigated. The frosted mass was affected considerably by the cooling block temperature and air humidity. However, the effect of air velocity on it was not so large. The pressure drop was affected remarkably by all experimental parameters in this study. Local heat flux distribution and frost thickness distribution on each fin were predicted from the measured fin temperatures and the mass and energy conservation equations on the frost surface and inside the frost layer. (author)

PREFACE: Aerodynamic sound Aerodynamic sound

Science.gov (United States)

Akishita, Sadao

2010-02-01

reduction of bluff-body noise. Xiaoyu Wang and Xiaofeng Sun discuss the interaction of fan stator and acoustic treatments using the transfer element method. S Saito and his colleagues in JAXA report the development of active devices for reducing helicopter noise. The paper by A Tamura and M Tsutahara proposes a brand new methodology for aerodynamic sound by applying the lattice Boltzmann finite difference method. As the method solves the fluctuation of air density directly, it has the advantage of not requiring modeling of the sound generation. M A Langthjem and M Nakano solve the hole-tone feedback cycle in jet flow by a numerical method. Y Ogami and S Akishita propose the application of a line-vortex method to the three-dimensional separated flow from a bluff body. I hope that a second issue on aerodynamic sound will be published in FDR in the not too distant future.

Sound reduction by metamaterial-based acoustic enclosure

Directory of Open Access Journals (Sweden)

Shanshan Yao

2014-12-01

Full Text Available In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of the source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.

Sound reduction by metamaterial-based acoustic enclosure

Energy Technology Data Exchange (ETDEWEB)

Yao, Shanshan; Li, Pei; Zhou, Xiaoming; Hu, Gengkai, E-mail: hugeng@bit.edu.cn [Key Laboratory of Dynamics and Control of Flight Vehicle, Ministry of Education and School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2014-12-15

In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of the source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.

Relationship between air mass type and emergency department visits for migraine headache across the Triangle region of North Carolina

Science.gov (United States)

Elcik, Christopher; Fuhrmann, Christopher M.; Mercer, Andrew E.; Davis, Robert E.

2017-12-01

An estimated 240 million people worldwide suffer from migraines. Because migraines are often debilitating, understanding the mechanisms that trigger them is crucial for effective prevention and treatment. Synoptic air mass types and emergency department (ED) visits for migraine headaches were examined over a 7-year period within a major metropolitan area of North Carolina to identify potential relationships between large-scale meteorological conditions and the incidence of migraine headaches. Barometric pressure changes associated with transitional air masses, or changing weather patterns, were also analyzed for potential relationships. Bootstrapping analysis revealed that tropical air masses (moist and dry) resulted in the greatest number of migraine ED visits over the study period, whereas polar air masses led to fewer. Moist polar air masses in particular were found to correspond with the fewest number of migraine ED visits. On transitional air mass days, the number of migraine ED visits fell between those of tropical air mass days and polar air mass days. Transitional days characterized by pressure increases exhibited a greater number of migraine ED visits than days characterized by pressure decreases. However, no relationship was found between migraine ED visits and the magnitude of barometric pressure changes associated with transitional air masses.

Gamma-ray dose rate increase at rainfall events and their air-mass origins

International Nuclear Information System (INIS)

Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

2007-01-01

The environmental γ-ray dose rate and precipitation rates were measured at our institute, in Rokkasho, Aomori, Japan. We analyzed 425 rainfall events in which the precipitation rate was over 0.5 mm from April through November during the years 2003 to 2005. Backward trajectories for 5 d starting from 1000 m above Rokkasho at the time of the maximum dose rate in a rainfall event, were calculated by using the HYSPLIT model of the NOAA Air Resources Laboratory. The trajectories for 5 d were classified by visual inspection according to the passage areas; Pacific Ocean, Asian Continent and Japan Islands. The increase of cumulative environmental γ-ray dose during a rainfall event was plotted against the precipitation in the event, and their relationship was separately examined according to the air-mass passage area, i.e. origin of the air-mass. Our results showed that the origin of air-mass was an important factor affecting the increase of environmental γ-ray dose rate by rainfall. (author)

Photoacoustic Sounds from Meteors.

Energy Technology Data Exchange (ETDEWEB)

Spalding, Richard E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tencer, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sweatt, William C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hogan, Roy E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Spurny, Pavel [Academy of Sciences of the Czech Republic (ASCR), Prague (Czech Republic)

2015-03-01

High-speed photometric observations of meteor fireballs have shown that they often produce high-amplitude light oscillations with frequency components in the kHz range, and in some cases exhibit strong millisecond flares. We built a light source with similar characteristics and illuminated various materials in the laboratory, generating audible sounds. Models suggest that light oscillations and pulses can radiatively heat dielectric materials, which in turn conductively heats the surrounding air on millisecond timescales. The sound waves can be heard if the illuminated material is sufficiently close to the observer’s ears. The mechanism described herein may explain many reports of meteors that appear to be audible while they are concurrently visible in the sky and too far away for sound to have propagated to the observer. This photoacoustic (PA) explanation provides an alternative to electrophonic (EP) sounds hypothesized to arise from electromagnetic coupling of plasma oscillation in the meteor wake to natural antennas in the vicinity of an observer.

Assessing the air pollution carrying capacity of the northern Puget Sound region: an application of TAPAS

Energy Technology Data Exchange (ETDEWEB)

Wood, M.C.; Childs J.E.; Marlatt, W.E.

1980-09-01

The technique discussed, the Topographic Air Pollution Analysis System (TAPAS), was developed to provide valid information on the dispersion capability of the lower atmosphere in areas characterized by complex terrain features. A study was undertaken to assess the air quality (SO/sub 2/) impacts associated with energy development in the region and to determine the constraints on energy development due to regulated limitations on the amount of air quality degradation allowable in the area. The emission constraint analysis for the northern Puget Sound region indicated that total SO/sub 2/ emissions in the core area (on an annual basis) are less than half of the amount that could be tolerated in the entire core region while maintaining ambient concentrations within state and federal annual average limitations. However, comparison of source characteristics with source location and grid cell emission restrictions indicated that localized areas adjacent to the major point sources are already far in excess of the SO/sub 2/ carrying capacity. This conclusion is supported by air quality monitoring data that indicate state standard violations at several receptor locations within the study area. The annual maps of wind patterns and PI-Matrix values show areas of both good and poor dispersion characteristics under the most prevalent flow conditions.

Calculation of sound propagation in fibrous materials

DEFF Research Database (Denmark)

Tarnow, Viggo

1996-01-01

Calculations of attenuation and velocity of audible sound waves in glass wools are presented. The calculations use only the diameters of fibres and the mass density of glass wools as parameters. The calculations are compared with measurements.......Calculations of attenuation and velocity of audible sound waves in glass wools are presented. The calculations use only the diameters of fibres and the mass density of glass wools as parameters. The calculations are compared with measurements....

Detailed evaluation of the natural circulation mass flow rate of water propelled by using an air injection

International Nuclear Information System (INIS)

Park, Rae-Joon; Ha, Kwang-Soon; Kim, Jae-Cheol; Hong, Seong-Wan; Kim, Sang-Baik

2008-01-01

One-dimensional (1D) air-water two-phase natural circulation flow in the thermohydraulic evaluation of reactor cooling mechanism by external self-induced flow - one-dimensional' (THERMES-1D) experiment has been verified and evaluated by using the RELAP5/MOD3 computer code. Experimental results on the 1D natural circulation mass flow rate of water propelled by using an air injection have been evaluated in detail. The RELAP5 results have shown that an increase in the air injection rate to 50% of the total heat flux leads to an increase in the water circulation mass flow rate. However, an increase in the air injection rate from 50 to 100% does not affect the water circulation mass flow rate, because of the inlet area condition. As the height increases in the air injection part, the void fraction increases. However, the void fraction in the upper part of the air injector maintains a constant value. An increase in the air injection mass flow rate leads to an increase in the local void fraction, but it has no influence on the local pressure. An increase in the coolant inlet area leads to an increase in the water circulation mass flow rate. However, the water outlet area does not have an influence on the water circulation mass flow rate. As the coolant outlet moves to a lower position, the water circulation mass flow rate decreases. (author)

A groundwater mass flux model for screening the groundwater-to-indoor-air exposure pathway

Energy Technology Data Exchange (ETDEWEB)

McHugh, T.; Blanc, P.C. de; Connor, J. [Groundwater Services Inc, Houston, TX (United States)

2003-07-01

The potential for human exposure via volatilisation of groundwater contaminants into indoor air has been a focus of increasing concern in recent years. At a small number of sites, elevated indoor vapour concentrations have been measured within buildings overlying shallow groundwater contaminated with chlorinated solvents, causing public concern over the potential for similar problems at other corrective action sites. In addition, use of the screening-levelmodel developed by Johnson and Ettinger (1991) for the groundwater-to-indoor-air exposure pathway has suggested that low microgram per litre (ug/L)-range concentrations of either chlorinated or non-chlorinated volatile organic compounds dissolved in groundwater could result in indoor vapour concentrations in excess of applicable risk-based exposure limits. As an alternative screening tool, this paper presents a groundwater mass flux model for evaluation of transport to indoor air. The mass flux model is intended to serve as a highly conservative screening tool that over-predicts groundwater-to-indoor-air mass flux, yet still provides sufficient sensitivity to identify sites for which the groundwater-to-indoor air exposure pathway is not a concern. (orig.)

Particle growth in an isoprene-rich forest: Influences of urban, wildfire, and biogenic air masses

Science.gov (United States)

Gunsch, Matthew J.; Schmidt, Stephanie A.; Gardner, Daniel J.; Bondy, Amy L.; May, Nathaniel W.; Bertman, Steven B.; Pratt, Kerri A.; Ault, Andrew P.

2018-04-01

Growth of freshly nucleated particles is an important source of cloud condensation nuclei (CCN) and has been studied within a variety of environments around the world. However, there remains uncertainty regarding the sources of the precursor gases leading to particle growth, particularly in isoprene-rich forests. In this study, particle growth events were observed from the 14 total events (31% of days) during summer measurements (June 24 - August 2, 2014) at the Program for Research on Oxidants PHotochemistry, Emissions, and Transport (PROPHET) tower within the forested University of Michigan Biological Station located in northern Michigan. Growth events were observed within long-range transported air masses from urban areas, air masses impacted by wildfires, as well as stagnant, forested/regional air masses. Growth events observed during urban-influenced air masses were prevalent, with presumably high oxidant levels, and began midday during periods of high solar radiation. This suggests that increased oxidation of biogenic volatile organic compounds (BVOCs) likely contributed to the highest observed particle growth in this study (8 ± 2 nm h-1). Growth events during wildfire-influenced air masses were observed primarily at night and had slower growth rates (3 ± 1 nm h-1). These events were likely influenced by increased SO2, O3, and NO2 transported within the smoke plumes, suggesting a role of NO3 oxidation in the production of semi-volatile compounds. Forested/regional air mass growth events likely occurred due to the oxidation of regionally emitted BVOCs, including isoprene, monoterpenes, and sesquiterpenes, which facilitated multiday growth events also with slower rates (3 ± 2 nm h-1). Intense sulfur, carbon, and oxygen signals in individual particles down to 20 nm, analyzed by transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX), suggest that H2SO4 and secondary organic aerosol contributed to particle growth. Overall, aerosol

A Comparison of Vibroacoustic Response of Isotropic Plate with Attached Discrete Patches and Point Masses Having Different Thickness Variation with Different Taper Ratios

Directory of Open Access Journals (Sweden)

Bipin Kumar

2016-01-01

Full Text Available A comparison of sound radiation behavior of plate in air medium with attached discrete patches/point masses having different thickness variations with different taper ratio of 0.3, 0.6, and 0.9 is analysed. Finite element method is used to find the vibration characteristics while Rayleigh integral is used to predict the sound radiation characteristics. Minimum peak sound power level obtained is at a taper ratio of 0.6 with parabolic increasing-decreasing thickness variation for plate with four discrete patches. At higher taper ratio, linearly increasing-decreasing thickness variation is another alternative for minimum peak sound power level suppression with discrete patches. It is found that, in low frequency range, average radiation efficiency remains almost the same, but near first peak, four patches or four point masses cause increase in average radiation efficiency; that is, redistribution of point masses/patches does have effect on average radiation efficiency at a given taper ratio.

Give Earth a Chance Series, Dirty Air, Trash Is Taking Over, Sounds and Silence, Pesticides Are Perilous, Tragedy in the Laundromat, Troublesome Tail Pipes.

Science.gov (United States)

Minneapolis Independent School District 275, Minn.

These six booklets in the "Give Earth a Chance Series" are titled, "Dirty Air,""Trash is Taking Over,""Sounds and Silence,""Pesticides are Perilous,""Tragedy in the Laundromat," and "Troublesome Tail Pipes." The booklets are suitable for elementary use, and are intended to…

Experimental investigation of sound absorption properties of perforated date palm fibers panel

International Nuclear Information System (INIS)

Elwaleed, A K; Nikabdullah, N; Nor, M J M; Tahir, M F M; Zulkifli, R

2013-01-01

This paper presents the sound absorption properties of a natural waste of date palm fiber perforated panel. A single layer of the date palm fibers was tested in this study for its sound absorption properties. The experimental measurements were carried out using impedance tube at the acoustic lab, Faculty of Engineering, Universiti Kebangsaan Malaysia. The experiment was conducted for the panel without air gap, with air gap and with perforated plate facing. Three air gap thicknesses of 10 mm, 20 mm and 30 mm were used between the date palm fiber sample and the rigid backing of the impedance tube. The results showed that when facing the palm date fiber sample with perforated plate the sound absorption coefficient improved at the higher and lower frequency ranges. This increase in sound absorption coincided with reduction in medium frequency absorption. However, this could be improved by using different densities or perforated plate with the date palm fiber panel.

Sound Insulation Property Study on Nylon 66 Scrim Reinforced PVF Laminated Membranes and their Composite Sound Proof Structure

Science.gov (United States)

Chen, Lihe; Chen, Zhaofeng; Zhang, Xinyang; Wang, Weiwei

2018-01-01

In this paper, we investigated the sound insulation property of nylon 66 scrim reinforced PVF laminated membranes and their corresponding composite structures with glass fiber felt and carbon fiber board. Sound transmission loss (STL) was measured by standing wave tube method. The results show that, with the decrease of nylon 66 gridlines spacing, STL of nylon 66 scrim reinforced PVF laminated membranes was improved. The sound insulation performance of laminated membranes with gridlines spacing of 3mm is the best, whose STL was up to 10dB at 6.3 kHz. Besides, STL was improved effectively as air layers were embedded into the composite sound proof construction consist of laminated membrane, glass fiber felt and carbon fiber board.

Mineralization of bacterial cell mass on a photocatalytic surface in air

International Nuclear Information System (INIS)

Jacoby, W.A.; Maness, P.C.; Wolfrum, E.J.; Blake, D.M.; Fennell, J.A.

1998-01-01

Whole cells deposited on a titanium dioxide-coated surface have been oxidized in air to carbon dioxide via photocatalysis. This paper provides the first evidence that the organic matter in whole cells can be completely oxidized. Three experimental techniques were employed to monitor this reaction: scanning electron microscopy, 14 C radioisotope labeling experiments establish that the carbon content of E. coli is oxidized to form carbon dioxide with substantial closure of the mass balance. The batch reactor experiments corroborate the mass balance and provide a preliminary indication of the rate of the oxidation reaction. These results provide evidence that a photocatalytic surface used for disinfection can also be self-cleaning in an air-solid system

New particle formation in air mass transported between two measurement sites in Northern Finland

Directory of Open Access Journals (Sweden)

M. Komppula

2006-01-01

Full Text Available This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events between these sites. In air masses of eastern origin almost all events were observed to start earlier at the eastern station Värriö, whereas in air masses of western origin most of the events were observed to start earlier at the western station Pallas. This demonstrates that particle formation in a certain air mass type depends not only on the diurnal variation of the parameters causing the phenomenon (such as photochemistry but also on some properties carried by the air mass itself. The correlation in growth rates between the two sites was relatively good, which suggests that the amount of condensable vapour causing the growth must have been at about the same level in both sites. The condensation sink was frequently much higher at the downwind station. It seems that secondary particle formation related to biogenic sources dominate in many cases over the particle sinks during the air mass transport between the sites. Two cases of transport from Pallas to Värriö were further analysed with an aerosol dynamics model. The model was able to reproduce the observed nucleation events 250 km down-wind at Värriö but revealed some differences between the two cases. The simulated nucleation rates were in both cases similar but the organic concentration profiles that best reproduced the observations were different in the two cases indicating that divergent formation reactions may dominate under different conditions. The simulations also suggested that organic compounds were the main contributor to new particle growth, which offers a tentative hypothesis to the distinct features of new particles at the two sites: Air masses arriving from the Atlantic Ocean typically spent approximately only ten hours over land before arriving at Pallas, and thus the time for the

climatology of air mass trajectories and aerosol optical thickness ...

African Journals Online (AJOL)

George

We present in this paper a climatological study of back trajectories of air masses ... obtained by inversion of photometric measurements of AERONET network. ... the arid Sahel region adjacent in the north to the Sahara ... the city a strategic position in the study of the .... atmospheric emergencies, diagnostic case studies and.

The beat is getting stronger : The effect of atmospheric stability on low frequency modulated sound of wind turbines

NARCIS (Netherlands)

van den Berg, G P

2005-01-01

Sound from wind turbines involves a number of sound production mechanisms related to different interactions between the turbine blades and the air. An important contribution to the low frequency part of the sound spectrum is due to the sudden variation in air flow which the blade encounters when it

Influence of drying air parameters on mass transfer characteristics of apple slices

Science.gov (United States)

Beigi, Mohsen

2016-10-01

To efficiently design both new drying process and equipment and/or to improve the existing systems, accurate values of mass transfer characteristics are necessary. The present study aimed to investigate the influence of drying air parameters (i.e. temperature, velocity and relative humidity) on effective diffusivity and convective mass transfer coefficient of apple slices. The Dincer and Dost model was used to determine the mass transfer characteristics. The obtained Biot number indicated that the moisture transfer in the apple slices was controlled by both internal and external resistance. The effective diffusivity and mass transfer coefficient values obtained to be in the ranges of 7.13 × 10-11-7.66 × 10-10 and 1.46 × 10-7-3.39 × 10-7 m s-1, respectively and the both of them increased with increasing drying air temperature and velocity, and decreasing relative humidity. The validation of the model showed that the model predicted the experimental drying curves of the samples with a good accuracy.

Vertical sounding balloons for stratospheric photochemistry

Science.gov (United States)

Pommereau, J. P.

The use of vertical sounding balloons for stratospheric photochemistry studies is illustrated by the use of a vertical piloted gas balloon for the search of NO2 diurnal variations. It is shown that the use of montgolfieres (hot air balloons) can enhance the vertical sounding technique. Particular attention is given to a sun-heated montgolfiere and to the more sophisticated infrared montgolfiere that is able to perform three to four vertical excursions per day and to remain aloft for weeks or months.

Panels with low-Q-factor resonators with theoretically infinite sound-proofing ability at a single frequency

Science.gov (United States)

Lazarev, L. A.

2015-07-01

An infinite panel with two types of resonators regularly installed on it is theoretically considered. Each resonator is an air-filled cavity hermetically closed by a plate, which executes piston vibrations. The plate and air inside the cavity play the roles of mass and elasticity, respectively. Every other resonator is reversed. At a certain ratio between the parameters of the resonators at the tuning frequency of the entire system, the acoustic-pressure force that directly affects the panel can be fully compensated by the action forces of the resonators. In this case, the sound-proofing ability (transmission loss) tends to infinity. The presented calculations show that a complete transmission-loss effect can be achieved even with low- Q resonators.

Microbial air quality in mass transport buses and work-related illness among bus drivers of Bangkok Mass Transit Authority.

Science.gov (United States)

Luksamijarulkul, Pipat; Sundhiyodhin, Viboonsri; Luksamijarulkul, Soavalug; Kaewboonchoo, Orawan

2004-06-01

The air quality in mass transport buses, especially air-conditioned buses may affect bus drivers who work full time. Bus numbers 16, 63, 67 and 166 of the Seventh Bus Zone of Bangkok Mass Transit Authority were randomly selected to investigate for microbial air quality. Nine air-conditioned buses and 2-4 open-air buses for each number of the bus (36 air-conditioned buses and 12 open-air buses) were included. Five points of in-bus air samples in each studied bus were collected by using the Millipore A ir Tester Totally, 180 and 60 air samples collected from air-conditioned buses and open-air buses were cultured for bacterial and fungal counts. The bus drivers who drove the studied buses were interviewed towards histories of work-related illness while working. The results revealed that the mean +/- SD of bacterial counts in the studied open-air buses ranged from 358.50 +/- 146.66 CFU/m3 to 506 +/- 137.62 CFU/m3; bus number 16 had the highest level. As well as the mean +/- SD of fungal counts which ranged from 93.33 +/- 44.83 CFU/m3 to 302 +/- 294.65 CFU/m3; bus number 166 had the highest level. Whereas, the mean +/- SD of bacterial counts in the studied air-conditioned buses ranged from 115.24 +/- 136.01 CFU/m3 to 244.69 +/- 234.85 CFU/m3; bus numbers 16 and 67 had the highest level. As well as the mean +/- SD of fungal counts which rangedfrom 18.84 +/- 39.42 CFU/m3 to 96.13 +/- 234.76 CFU/m3; bus number 166 had the highest level. When 180 and 60 studied air samples were analyzed in detail, it was found that 33.33% of the air samples from open-air buses and 6.11% of air samples from air-conditioned buses had a high level of bacterial counts (> 500 CFU/m3) while 6.67% of air samples from open-air buses and 2.78% of air samples from air-conditioned buses had a high level of fungal counts (> 500 CFU/m3). Data from the history of work-related illnesses among the studied bus drivers showed that 91.67% of open-air bus drivers and 57.28% of air-conditioned bus drivers had

Kinetic-sound propagation in dilute gas mixtures

International Nuclear Information System (INIS)

Campa, A.; Cohen, E.G.D.

1989-01-01

Kinetic sound is predicted in dilute disparate-mass binary gas mixtures, propagating exclusively in the light compound and much faster than ordinary sound. It should be detectable by light-scattering experiments, as an extended shoulder in the scattering cross section for large frequencies. As an example, H 2 -Ar mixtures are discussed

Evidence for direct geographic influences on linguistic sounds: the case of ejectives.

Directory of Open Access Journals (Sweden)

Caleb Everett

Full Text Available We present evidence that the geographic context in which a language is spoken may directly impact its phonological form. We examined the geographic coordinates and elevations of 567 language locations represented in a worldwide phonetic database. Languages with phonemic ejective consonants were found to occur closer to inhabitable regions of high elevation, when contrasted to languages without this class of sounds. In addition, the mean and median elevations of the locations of languages with ejectives were found to be comparatively high. The patterns uncovered surface on all major world landmasses, and are not the result of the influence of particular language families. They reflect a significant and positive worldwide correlation between elevation and the likelihood that a language employs ejective phonemes. In addition to documenting this correlation in detail, we offer two plausible motivations for its existence. We suggest that ejective sounds might be facilitated at higher elevations due to the associated decrease in ambient air pressure, which reduces the physiological effort required for the compression of air in the pharyngeal cavity--a unique articulatory component of ejective sounds. In addition, we hypothesize that ejective sounds may help to mitigate rates of water vapor loss through exhaled air. These explications demonstrate how a reduction of ambient air density could promote the usage of ejective phonemes in a given language. Our results reveal the direct influence of a geographic factor on the basic sound inventories of human languages.

Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement

Energy Technology Data Exchange (ETDEWEB)

Desantes, J.M.; Galindo, J.; Guardiola, C.; Dolz, V. [CMT - Motores Termicos, Universidad Politecnica de Valencia (Spain)

2010-01-15

Air mass flow determination is needed for the control of current internal combustion engines. Current methods are based on specific sensors (as hot wire anemometers) or indirect estimation through manifold pressure. With the availability of cylinder pressure sensors for engine control, methods based on them can be used for replacing or complementing standard methods. Present paper uses in cylinder pressure increase during the intake stroke for inferring the trapped air mass. The method is validated on two different turbocharged diesel engines and compared with the standard methods. (author)

[The application of vibrant sound bridge in microtia whose reconstructive external auditory canal occurred atresia].

Science.gov (United States)

Zhao, Shouqin; Gong, Shusheng; Han, Demin; Chen, Shubin; Li, Yi; Ma, Xiaobo; Liu, Haihong

2012-05-01

To investigate the effect of vibrant sound bridge implantation in microtia whose reconstructive external auditory canal occurred atresia. Three cases (2 males and 1 female) of microtia had underwent hearing reconstruction operation (Include the external ear canal reconstructive surgery and tympanoplasty). The age ranged from 15 to 18 years and the average age was 17 years. All the 3 cases suffered from conductive hearing loss with the air-bone gap ranging from 51.6 to 65.0 dB HL and the average value being 56. 3 dB HL. All the 3 cases underwent vibrant sound bridge implantation, including the floating mass transducer implanted in the head of stapes in 2 cases and in the niche of round window in 1 case. The postoperative hearing level improved from 21.6 to 52.5 dB HL with an average of 32.2 dB HL. There were no complications such as vertigo, tinnitus and facial paralysis. Through vibrant sound bridge implantation, the hearing level of microtia whose reconstructive external auditory canal occurred atresia was improved effectively.

Physics of thermo-acoustic sound generation

Science.gov (United States)

Daschewski, M.; Boehm, R.; Prager, J.; Kreutzbruck, M.; Harrer, A.

2013-09-01

We present a generalized analytical model of thermo-acoustic sound generation based on the analysis of thermally induced energy density fluctuations and their propagation into the adjacent matter. The model provides exact analytical prediction of the sound pressure generated in fluids and solids; consequently, it can be applied to arbitrary thermal power sources such as thermophones, plasma firings, laser beams, and chemical reactions. Unlike existing approaches, our description also includes acoustic near-field effects and sound-field attenuation. Analytical results are compared with measurements of sound pressures generated by thermo-acoustic transducers in air for frequencies up to 1 MHz. The tested transducers consist of titanium and indium tin oxide coatings on quartz glass and polycarbonate substrates. The model reveals that thermo-acoustic efficiency increases linearly with the supplied thermal power and quadratically with thermal excitation frequency. Comparison of the efficiency of our thermo-acoustic transducers with those of piezoelectric-based airborne ultrasound transducers using impulse excitation showed comparable sound pressure values. The present results show that thermo-acoustic transducers can be applied as broadband, non-resonant, high-performance ultrasound sources.

Topology optimized cloak for airborne sound

DEFF Research Database (Denmark)

Andkjær, Jacob Anders; Sigmund, Ole

2013-01-01

Directional acoustic cloaks that conceal an aluminum cylinder for airborne sound waves are presented in this paper. Subwavelength cylindrical aluminum inclusions in air constitute the cloak design to aid practical realizations. The positions and radii of the subwavelength cylinders are determined...

Enhancement of acoustical performance of hollow tube sound absorber

International Nuclear Information System (INIS)

Putra, Azma; Khair, Fazlin Abd; Nor, Mohd Jailani Mohd

2016-01-01

This paper presents acoustical performance of hollow structures utilizing the recycled lollipop sticks as acoustic absorbers. The hollow cross section of the structures is arranged facing the sound incidence. The effects of different length of the sticks and air gap on the acoustical performance are studied. The absorption coefficient was measured using impedance tube method. Here it is found that improvement on the sound absorption performance is achieved by introducing natural kapok fiber inserted into the void between the hollow structures. Results reveal that by inserting the kapok fibers, both the absorption bandwidth and the absorption coefficient increase. For test sample backed by a rigid surface, best performance of sound absorption is obtained for fibers inserted at the front and back sides of the absorber. And for the case of test sample with air gap, this is achieved for fibers introduced only at the back side of the absorber.

Enhancement of acoustical performance of hollow tube sound absorber

Energy Technology Data Exchange (ETDEWEB)

Putra, Azma, E-mail: azma.putra@utem.edu.my; Khair, Fazlin Abd, E-mail: fazlinabdkhair@student.utem.edu.my; Nor, Mohd Jailani Mohd, E-mail: jai@utem.edu.my [Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Durian Tunggal Melaka 76100 Malaysia (Malaysia)

2016-03-29

This paper presents acoustical performance of hollow structures utilizing the recycled lollipop sticks as acoustic absorbers. The hollow cross section of the structures is arranged facing the sound incidence. The effects of different length of the sticks and air gap on the acoustical performance are studied. The absorption coefficient was measured using impedance tube method. Here it is found that improvement on the sound absorption performance is achieved by introducing natural kapok fiber inserted into the void between the hollow structures. Results reveal that by inserting the kapok fibers, both the absorption bandwidth and the absorption coefficient increase. For test sample backed by a rigid surface, best performance of sound absorption is obtained for fibers inserted at the front and back sides of the absorber. And for the case of test sample with air gap, this is achieved for fibers introduced only at the back side of the absorber.

Match properties of heat transfer and coupled heat and mass transfer processes in air-conditioning system

International Nuclear Information System (INIS)

Zhang Tao; Liu Xiaohua; Zhang Lun; Jiang Yi

2012-01-01

Highlights: ► Investigates match properties of heat or mass transfer processes in HVAC system. ► Losses are caused by limited transfer ability, flow and parameter mismatching. ► Condition of flow matching is the same heat capacity of the fluids. ► Parameter matching is only reached along the saturation line in air–water system. ► Analytical solutions of heat and mass transfer resistance are derived. - Abstract: Sensible heat exchangers and coupled heat and mass transfer devices between humid air and water/desiccant are commonly used devices in air-conditioning systems. This paper focuses on the match properties of sensible heat transfer processes and coupled heat and mass transfer processes in an effort to understand the reasons for performance limitations in order to optimize system performance. Limited heat transfer capability and flow mismatching resulted in heat resistance of the sensible heat transfer process. Losses occurred during the heat and mass transfer processes due to limited transfer capability, flow mismatching, and parameter mismatching. Flow matching was achieved when the heat capacities of the fluids were identical, and parameter matching could only be reached along the saturation line in air–water systems or the iso-concentration line in air–desiccant systems. Analytical solutions of heat transfer resistance and mass transfer resistance were then derived. The heat and mass transfer process close to the saturation line is recommended, and heating sprayed water resulted in better humidification performance than heating inlet air in the air humidifier.

Sound Wave Energy Resulting from the Impact of Water Drops on the Soil Surface.

Science.gov (United States)

Ryżak, Magdalena; Bieganowski, Andrzej; Korbiel, Tomasz

2016-01-01

The splashing of water drops on a soil surface is the first step of water erosion. There have been many investigations into splashing-most are based on recording and analysing images taken with high-speed cameras, or measuring the mass of the soil moved by splashing. Here, we present a new aspect of the splash phenomenon's characterization the measurement of the sound pressure level and the sound energy of the wave that propagates in the air. The measurements were carried out for 10 consecutive water drop impacts on the soil surface. Three soils were tested (Endogleyic Umbrisol, Fluvic Endogleyic Cambisol and Haplic Chernozem) with four initial moisture levels (pressure heads: 0.1 kPa, 1 kPa, 3.16 kPa and 16 kPa). We found that the values of the sound pressure and sound wave energy were dependent on the particle size distribution of the soil, less dependent on the initial pressure head, and practically the same for subsequent water drops (from the first to the tenth drop). The highest sound pressure level (and the greatest variability) was for Endogleyic Umbrisol, which had the highest sand fraction content. The sound pressure for this soil increased from 29 dB to 42 dB with the next incidence of drops falling on the sample The smallest (and the lowest variability) was for Fluvic Endogleyic Cambisol which had the highest clay fraction. For all experiments the sound pressure level ranged from ~27 to ~42 dB and the energy emitted in the form of sound waves was within the range of 0.14 μJ to 5.26 μJ. This was from 0.03 to 1.07% of the energy of the incident drops.

Sound Wave Energy Resulting from the Impact of Water Drops on the Soil Surface.

Directory of Open Access Journals (Sweden)

Magdalena Ryżak

Full Text Available The splashing of water drops on a soil surface is the first step of water erosion. There have been many investigations into splashing-most are based on recording and analysing images taken with high-speed cameras, or measuring the mass of the soil moved by splashing. Here, we present a new aspect of the splash phenomenon's characterization the measurement of the sound pressure level and the sound energy of the wave that propagates in the air. The measurements were carried out for 10 consecutive water drop impacts on the soil surface. Three soils were tested (Endogleyic Umbrisol, Fluvic Endogleyic Cambisol and Haplic Chernozem with four initial moisture levels (pressure heads: 0.1 kPa, 1 kPa, 3.16 kPa and 16 kPa. We found that the values of the sound pressure and sound wave energy were dependent on the particle size distribution of the soil, less dependent on the initial pressure head, and practically the same for subsequent water drops (from the first to the tenth drop. The highest sound pressure level (and the greatest variability was for Endogleyic Umbrisol, which had the highest sand fraction content. The sound pressure for this soil increased from 29 dB to 42 dB with the next incidence of drops falling on the sample The smallest (and the lowest variability was for Fluvic Endogleyic Cambisol which had the highest clay fraction. For all experiments the sound pressure level ranged from ~27 to ~42 dB and the energy emitted in the form of sound waves was within the range of 0.14 μJ to 5.26 μJ. This was from 0.03 to 1.07% of the energy of the incident drops.

Urban sound energy reduction by means of sound barriers

Science.gov (United States)

Iordache, Vlad; Ionita, Mihai Vlad

2018-02-01

In urban environment, various heating ventilation and air conditioning appliances designed to maintain indoor comfort become urban acoustic pollution vectors due to the sound energy produced by these equipment. The acoustic barriers are the recommended method for the sound energy reduction in urban environment. The current sizing method of these acoustic barriers is too difficult and it is not practical for any 3D location of the noisy equipment and reception point. In this study we will develop based on the same method a new simplified tool for acoustic barriers sizing, maintaining the same precision characteristic to the classical method. Abacuses for acoustic barriers sizing are built that can be used for different 3D locations of the source and the reception points, for several frequencies and several acoustic barrier heights. The study case presented in the article represents a confirmation for the rapidity and ease of use of these abacuses in the design of the acoustic barriers.

Urban sound energy reduction by means of sound barriers

Directory of Open Access Journals (Sweden)

Iordache Vlad

2018-01-01

Full Text Available In urban environment, various heating ventilation and air conditioning appliances designed to maintain indoor comfort become urban acoustic pollution vectors due to the sound energy produced by these equipment. The acoustic barriers are the recommended method for the sound energy reduction in urban environment. The current sizing method of these acoustic barriers is too difficult and it is not practical for any 3D location of the noisy equipment and reception point. In this study we will develop based on the same method a new simplified tool for acoustic barriers sizing, maintaining the same precision characteristic to the classical method. Abacuses for acoustic barriers sizing are built that can be used for different 3D locations of the source and the reception points, for several frequencies and several acoustic barrier heights. The study case presented in the article represents a confirmation for the rapidity and ease of use of these abacuses in the design of the acoustic barriers.

The Frequency of Occurrence of Air Masses Over Twelve European Cities.

Science.gov (United States)

1983-01-01

cluster analysis technique to investigate the possibility of simplifying the European "",Oskar Essermanger, 1954, Neue Methode der Zerleang von...Masses, Streamlines, and the Boreal Forest," Geographical Bulletin, Vol 8 11 J. M. Davis, 1981, The Use of Cluster Analysis in the Identification and...Atmosphere and a Proposed Model for Frontal Analysis," Tellus, Vol 5 ’’N. S. McDonald, 1975, "Etgenvectur Analisis as an Aid to Air Mass Recognition

Evidence of mass exchange between inside and outside of sonoluminescing bubble in aqueous solution of terbium chloride

Energy Technology Data Exchange (ETDEWEB)

Liang, Jinfu, E-mail: liang.shi2007@163.com [School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001 (China); Chen, Weizhong, E-mail: wzchen@nju.edu.cn [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); Wang, Xun; Yang, Jing; Chen, Zhan [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China)

2016-12-16

Highlights: • Time-resolved spectra of SBSL were obtained for Tb{sup 3+} ions emission lines. • Mass exchange between inside and outside of SL bubble was probed via Tb{sup 3+} ions lines. • The argon rectification hypothesis was tested by time-resolved spectra of SBSL. • The rate of mass exchange inside an SBSL bubble increases with increasing sound pressure. - Abstract: Spectra of single-bubble sonoluminescence (SBSL) were obtained for Tb{sup 3+} ions emission lines from bubbles in an aqueous solution of terbium chloride (TbCl{sub 3}). The spectra provide experimental evidence to prove that an air bubble driven by strong ultrasound will not eventually become a rectified pure argon bubble, which is not as predicted by the argon rectification hypothesis. The time-resolved spectra of SBSL show a mass exchange of material such as Tb{sup 3+} ions between the inside and outside of the bubble. With increasing sound pressure, the rate of mass exchange and the SBSL intensity increases.

Characterising terrestrial influences on Antarctic air masses using Radon-222 measurements at King George Island

Science.gov (United States)

Chambers, S. D.; Hong, S.-B.; Williams, A. G.; Crawford, J.; Griffiths, A. D.; Park, S.-J.

2014-09-01

We report on one year of high-precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m-3 in late-summer to 44 mBq m-3 in late winter and early spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m-3, were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47-53° S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8-4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.

Study of mass transfer at the air-water interface by an isotopic method

International Nuclear Information System (INIS)

Merlivat, L.

1975-01-01

It is shown by analysing the hydrogen and oxygen stable isotopes distribution in liquid and water vapor, that the processes taking place on a very small scale near the liquid can be investigated. The effect of molecular mass transfer is directly obtained without having to perform difficult measurements in the air in the immediate vicinity of the water surface. Experiments are carried out in the air-water tunnel especially designed for the simulation of ocean atmosphere energy exchanges. The wind velocities vary from 0.7 to 7m/sec. The experimental results obtained do not support the classical Reynolds' analogy between momentum and mass transfer down to the interface and the theory proposed by Sheppard, but they are in agreement with Sverdrup's, Kitaigorodskiy and Volkov's and Brutsaert's theories, all of which involve a layer just above the air-water interface through which mass transfer is dominated by molecular diffusion. The thickness of this layer in the two first theories is shown to decrease with increasing wind velocity. Direct application of Brutsaert's theory for roughness Reynolds numbers smaller than one is in good agreement with the experimental data obtained [fr

Mass concentrations of BTEX inside air environment of buses in Changsha, China

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiaokai; Zhang, Guoqiang; Zhang, Quan [College of Civil Engineering, Hunan University, Changsha 410082, Hunan (China); Chen, Hong [College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan (China)

2011-02-15

In order to estimate the mass concentrations of benzene (B), toluene (T), ethylbenzene (E) and xylenes (X) inside air environment of buses and to analyze the influencing factors of the BTEX pollution levels, 22 public buses were investigated in Changsha, China. The interior air was collected through activated charcoal adsorption tubes and then the air samples were analyzed with thermally desorbed gas chromatograph. The mass concentrations ranged from 21.3 to 106.4 {mu}g/m{sup 3} for benzene, from 53.5 to 266.0 {mu}g/m{sup 3} for toluene, from 19.6 to 95.9 {mu}g/m{sup 3} for ethylbenzene and from 46.9 to 234.8 {mu}g/m{sup 3} for xylenes. Their mean values were 68.7, 179.7, 62.5 and 151.8 {mu}g/m{sup 3}, respectively. The rates of buses tested where the interior concentrations exceeded the limit levels of Chinese Indoor Air Quality Standard were 45.5% for toluene and 13.6% for xylenes. The BTEX levels increased when in-car temperature or relative humidity rose, and decreased when car age or travel distance increased. The BTEX concentrations were higher in leather trims buses than in non-leather trims ones, in air-conditioned buses than in non-air-conditioned ones, and in high-grade buses than in low-grade ones. According to the analysis of multiple linear regression equation, car age and in-car temperature were two most important factors influencing the BTEX pollution levels in the cabins of public buses. (author)

Photochemical aging of aerosol particles in different air masses arriving at Baengnyeong Island, Korea

Science.gov (United States)

Kang, Eunha; Lee, Meehye; Brune, William H.; Lee, Taehyoung; Park, Taehyun; Ahn, Joonyoung; Shang, Xiaona

2018-05-01

Atmospheric aerosol particles are a serious health risk, especially in regions like East Asia. We investigated the photochemical aging of ambient aerosols using a potential aerosol mass (PAM) reactor at Baengnyeong Island in the Yellow Sea during 4-12 August 2011. The size distributions and chemical compositions of aerosol particles were measured alternately every 6 min from the ambient air or through the highly oxidizing environment of a potential aerosol mass (PAM) reactor. Particle size and chemical composition were measured by using the combination of a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Inside the PAM reactor, O3 and OH levels were equivalent to 4.6 days of integrated OH exposure at typical atmospheric conditions. Two types of air masses were distinguished on the basis of the chemical composition and the degree of aging: air transported from China, which was more aged with a higher sulfate concentration and O : C ratio, and the air transported across the Korean Peninsula, which was less aged with more organics than sulfate and a lower O : C ratio. For both episodes, the particulate sulfate mass concentration increased in the 200-400 nm size range when sampled through the PAM reactor. A decrease in organics was responsible for the loss of mass concentration in 100-200 nm particles when sampled through the PAM reactor for the organics-dominated episode. This loss was especially evident for the m/z 43 component, which represents less oxidized organics. The m/z 44 component, which represents further oxidized organics, increased with a shift toward larger sizes for both episodes. It is not possible to quantify the maximum possible organic mass concentration for either episode because only one OH exposure of 4.6 days was used, but it is clear that SO2 was a primary precursor of secondary aerosol in northeast Asia, especially during long-range transport from China. In addition

Misconceptions About Sound Among Engineering Students

Science.gov (United States)

Pejuan, Arcadi; Bohigas, Xavier; Jaén, Xavier; Periago, Cristina

2012-12-01

Our first objective was to detect misconceptions about the microscopic nature of sound among senior university students enrolled in different engineering programmes (from chemistry to telecommunications). We sought to determine how these misconceptions are expressed (qualitative aspect) and, only very secondarily, to gain a general idea of the extent to which they are held (quantitative aspect). Our second objective was to explore other misconceptions about wave aspects of sound. We have also considered the degree of consistency in the model of sound used by each student. Forty students answered a questionnaire including open-ended questions. Based on their free, spontaneous answers, the main results were as follows: a large majority of students answered most of the questions regarding the microscopic model of sound according to the scientifically accepted model; however, only a small number answered consistently. The main model misconception found was the notion that sound is propagated through the travelling of air particles, even in solids. Misconceptions and mental-model inconsistencies tended to depend on the engineering programme in which the student was enrolled. However, students in general were inconsistent also in applying their model of sound to individual sound properties. The main conclusion is that our students have not truly internalised the scientifically accepted model that they have allegedly learnt. This implies a need to design learning activities that take these findings into account in order to be truly efficient.

Self-collimated slow sound in sonic crystals

International Nuclear Information System (INIS)

Kaya, Olgun Adem; Cicek, Ahmet; Ulug, Bulent

2012-01-01

Self-collimated slow-sound propagation in a two-dimensional rectangular sonic crystal composed of elliptical scatterers in air is numerically demonstrated. The group velocity at the centre and the edges of the fourth acoustic band is reduced to 45 m s -1 and 30 m s -1 , corresponding to 1/8 and 1/12 of the speed of sound in air, respectively. Elimination of omni-directional reflections encountered in linear waveguides and the reduction of group-velocity dispersion at the mid-band frequencies lead to preservation of pulse shape and amplitude upon traversal of the sonic crystal. Wave transmission is increased from approximately -20 to -2.5 dB, with almost an order of magnitude enhancement, via injector layers optimized through a pattern search algorithm. Self-collimating performance of the system is not degraded under oblique incidence, except for pulse broadening due to increased effective source width.

An open-structure sound insulator against low-frequency and wide-band acoustic waves

Science.gov (United States)

Chen, Zhe; Fan, Li; Zhang, Shu-yi; Zhang, Hui; Li, Xiao-juan; Ding, Jin

2015-10-01

To block sound, i.e., the vibration of air, most insulators are based on sealed structures and prevent the flow of the air. In this research, an acoustic metamaterial adopting side structures, loops, and labyrinths, arranged along a main tube, is presented. By combining the accurately designed side structures, an extremely wide forbidden band with a low cut-off frequency of 80 Hz is produced, which demonstrates a powerful low-frequency and wide-band sound insulation ability. Moreover, by virtue of the bypass arrangement, the metamaterial is based on an open structure, and thus air flow is allowed while acoustic waves can be insulated.

Physical aerosol properties and their relation to air mass origin at Monte Cimone (Italy during the first MINATROC campaign

Directory of Open Access Journals (Sweden)

R. Van Dingenen

2005-01-01

Full Text Available Aerosol physical properties were measured at the Monte Cimone Observatory (Italy from 1 June till 6 July 2000. The measurement site is located in the transition zone between the continental boundary layer and the free troposphere (FT, at the border between the Mediterranean area and Central Europe, and is exposed to a variety of air masses. Sub-μm number size distributions, aerosol hygroscopicity near 90% RH, refractory size distribution at 270°C and equivalent black carbon mass were continuously measured. Number size distributions and hygroscopic properties indicate that the site is exposed to aged continental air masses, however during daytime it is also affected by upslope winds. The mixing of this transported polluted boundary layer air masses with relatively clean FT air leads to frequent nucleation events around local noon. Night-time size distributions, including fine and coarse fractions for each air mass episode, have been parameterized by a 3-modal lognormal distribution. Number and volume concentrations in the sub-μm modes are strongly affected by the air mass origin, with highest levels in NW-European air masses, versus very clean, free tropospheric air coming from the N-European sector. During a brief but distinct dust episode, the coarse mode is clearly enhanced. The observed hygroscopic behavior of the aerosol is consistent with the chemical composition described by Putaud et al. (2004, but no closure between known chemical composition and measured hygroscopicity could be made because the hygroscopic properties of the water-soluble organic matter (WSOM are not known. The data suggest that WSOM is slightly-to-moderately hygroscopic (hygroscopic growth factor GF at 90% relative humidity between 1.05 and 1.51, and that this property may well depend on the air mass origin and history. External mixing of aerosol particles is observed in all air masses through the occurrence of two hygroscopicity modes (average GF of 1.22 and 1

Feasibility of a low-cost sounding rockoon platform

Science.gov (United States)

Okninski, Adam; Raurell, Daniel Sors; Mitre, Alberto Rodriguez

2016-10-01

This paper presents the results of analyses and simulations for the design of a small sounding platform, dedicated to conducting scientific atmospheric research and capable of reaching the von Kármán line by means of a rocket launched from it. While recent private initiatives have opted for the air launch concept to send small payloads to Low Earth Orbit, several historical projects considered the use of balloons as the first stage of orbital and suborbital platforms, known as rockoons. Both of these approaches enable the minimization of drag losses. This paper addresses the issue of utilizing stratospheric balloons as launch platforms to conduct sub-orbital rocket flights. Research and simulations have been conducted to demonstrate these capabilities and feasibility. A small sounding solid propulsion rocket using commercially-off-the-shelf hardware is proposed. Its configuration and design are analyzed with special attention given to the propulsion system and its possible mission-orientated optimization. The cost effectiveness of this approach is discussed. Performance calculation outcomes are shown. Additionally, sensitivity study results for different design parameters are given. Minimum mass rocket configurations for various payload requirements are presented. The ultimate aim is to enhance low-cost experimentation maintaining high mobility of the system and simplicity of operations. An easier and more affordable access to a space-like environment can be achieved with this system, thus allowing for widespread outreach of space science and technology knowledge. This project is based on earlier experience of the authors in LEEM Association of the Technical University of Madrid and the Polish Small Sounding Rocket Program developed at the Institute of Aviation and Warsaw University of Technology in Poland.

Hot-wire air flow meter for gasoline fuel-injection system. Calculation of air mass in cylinder during transient condition; Gasoline funsha system yo no netsusenshiki kuki ryuryokei. Kato untenji no cylinder juten kukiryo no keisan

Energy Technology Data Exchange (ETDEWEB)

Oyama, Y [Hitachi Car Engineering, Ltd., Tokyo (Japan); Nishimura, Y; Osuga, M; Yamauchi, T [Hitachi, Ltd., Tokyo (Japan)

1997-10-01

Air flow characteristics of hot-wire air flow meters for gasoline fuel-injection systems with supercharging and exhaust gas recycle during transient conditions were investigated to analyze a simple method for calculating air mass in cylinder. It was clarified that the air mass in cylinder could be calculated by compensating for the change of air mass in intake system by using aerodynamic models of intake system. 3 refs., 6 figs., 1 tab.

The impact of the microphone position on the frequency analysis of snoring sounds.

Science.gov (United States)

Herzog, Michael; Kühnel, Thomas; Bremert, Thomas; Herzog, Beatrice; Hosemann, Werner; Kaftan, Holger

2009-08-01

Frequency analysis of snoring sounds has been reported as a diagnostic tool to differentiate between different sources of snoring. Several studies have been published presenting diverging results of the frequency analyses of snoring sounds. Depending on the position of the used microphones, the results of the frequency analysis of snoring sounds vary. The present study investigated the influence of different microphone positions on the outcome of the frequency analysis of snoring sounds. Nocturnal snoring was recorded simultaneously at six positions (air-coupled: 30 cm middle, 100 cm middle, 30 cm lateral to both sides of the patients' head; body contact: neck and parasternal) in five patients. The used microphones had a flat frequency response and a similar frequency range (10/40 Hz-18 kHz). Frequency analysis was performed by fast Fourier transformation and frequency bands as well as peak intensities (Peaks 1-5) were detected. Air-coupled microphones presented a wider frequency range (60 Hz-10 kHz) compared to contact microphones. The contact microphone at cervical position presented a cut off at frequencies above 300 Hz, whereas the contact microphone at parasternal position revealed a cut off above 100 Hz. On an exemplary base, the study demonstrates that frequencies above 1,000 Hz do appear in complex snoring patterns, and it is emphasised that high frequencies are imported for the interpretation of snoring sounds with respect to the identification of the source of snoring. Contact microphones might be used in screening devices, but for a natural analysis of snoring sounds the use of air-coupled microphones is indispensable.

A Sounding-based Severe Weather Tool to Support Daily Operations at Kennedy Space Center and Cape Canaveral Air Force Station

Science.gov (United States)

Bauman, William H.; Roeder, William P.

2014-01-01

People and property at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) are at risk when severe weather occurs. Strong winds, hail and tornadoes can injure individuals and cause costly damage to structures if not properly protected. NASA's Launch Services Program and Ground Systems Development and Operations Program and other KSC programs use the daily and weekly severe weather forecasts issued by the 45th Weather Squadron (45 WS) to determine if they need to limit an activity such as working on gantries, or protect property such as a vehicle on a pad. The 45 WS requested the Applied Meteorology Unit (AMU) develop a warm season (May-September) severe weather tool for use in the Meteorological Interactive Data Display System (MIDDS) based on the late morning, 1500 UTC (1100 local time), CCAFS (XMR) sounding. The 45 WS frequently makes decisions to issue a severe weather watch and other severe weather warning support products to NASA and the 45th Space Wing in the late morning, after the 1500 UTC sounding. The results of this work indicate that certain stability indices based on the late morning XMR soundings can depict differences between days with reported severe weather and days with no reported severe weather. The AMU determined a frequency of reported severe weather for the stability indices and implemented an operational tool in MIDDS.

Foley Sounds vs Real Sounds

DEFF Research Database (Denmark)

Trento, Stefano; Götzen, Amalia De

2011-01-01

This paper is an initial attempt to study the world of sound effects for motion pictures, also known as Foley sounds. Throughout several audio and audio-video tests we have compared both Foley and real sounds originated by an identical action. The main purpose was to evaluate if sound effects...

Sound-like collective mode excitation with pion absorption in nuclear matter

International Nuclear Information System (INIS)

Qiu Xijiun; Shen Jianguo; Huang Lingfang

1985-01-01

The relativistic mean field theory consistent with bulk properties of nuclear matter is extended to study the excitations of the sound-like collective modes in nuclear matter. Corresponding relativistic mean field equations are solved numerically and self-consistently. The effective mass of nucleon, the speed of the sound and the amplitude of the sound-like solution are calculated. When the nuclear density is near or greater than the saturation density, the sound-like non-trivial solution could be found

Imperiling urban environment through varying air pollution rein in measures and mass transit policies - a case study of Lahore

International Nuclear Information System (INIS)

Aziz, A.

2015-01-01

Gargantuan expansion of big cities has increased motor vehicular tremendously. Lahore, a primitive green city is now gripped with swelling motor vehicular air pollution. Mass public transport, a back bone of city transportation network, due to erroneous running significantly contributes toward motor vehicular air pollution. Policy initiatives of the Government to curb motor vehicular air pollution are merely focused upon reduction of air pollution at source by the use of technology and clean fuel programmes. The policies for introduction of mass transit remained imprecise which lead to rise in transportation demand and increase in surfeit emission; Half-baked policies normally stem out to get political popularity which imperils urban environment. The paper highlights inconsistent policy measures and unsound air pollution control strategies adopted in big cities of Pakistan. Furthermore it gives guidance for sustainable mass transit policy measures. (author)

78 FR 13869 - Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy...

Science.gov (United States)

2013-03-01

...-123-LNG; 12-128-NG; 12-148-NG; 12- 158-NG] Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; CE FLNG, LLC; Consolidated...-NG Puget Sound Energy, Inc Order granting long- term authority to import/export natural gas from/to...

The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-convective Wind Event

Science.gov (United States)

Berndt, E. B.; Zavodsky, B. T.; Jedlovec, G. J.; Molthan, A. L.

2013-01-01

Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses.

Control of Toxic Chemicals in Puget Sound, Phase 3: Study of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

Energy Technology Data Exchange (ETDEWEB)

Brandenberger, Jill M.; Louchouarn, Patrick; Kuo, Li-Jung; Crecelius, Eric A.; Cullinan, Valerie I.; Gill, Gary A.; Garland, Charity R.; Williamson, J. B.; Dhammapala, R.

2010-07-05

The results of the Phase 1 Toxics Loading study suggested that runoff from the land surface and atmospheric deposition directly to marine waters have resulted in considerable loads of contaminants to Puget Sound (Hart Crowser et al. 2007). The limited data available for atmospheric deposition fluxes throughout Puget Sound was recognized as a significant data gap. Therefore, this study provided more recent or first reported atmospheric deposition fluxes of PAHs, PBDEs, and select trace elements for Puget Sound. Samples representing bulk atmospheric deposition were collected during 2008 and 2009 at seven stations around Puget Sound spanning from Padilla Bay south to Nisqually River including Hood Canal and the Straits of Juan de Fuca. Revised annual loading estimates for atmospheric deposition to the waters of Puget Sound were calculated for each of the toxics and demonstrated an overall decrease in the atmospheric loading estimates except for polybrominated diphenyl ethers (PBDEs) and total mercury (THg). The median atmospheric deposition flux of total PBDE (7.0 ng/m2/d) was higher than that of the Hart Crowser (2007) Phase 1 estimate (2.0 ng/m2/d). The THg was not significantly different from the original estimates. The median atmospheric deposition flux for pyrogenic PAHs (34.2 ng/m2/d; without TCB) shows a relatively narrow range across all stations (interquartile range: 21.2- 61.1 ng/m2/d) and shows no influence of season. The highest median fluxes for all parameters were measured at the industrial location in Tacoma and the lowest were recorded at the rural sites in Hood Canal and Sequim Bay. Finally, a semi-quantitative apportionment study permitted a first-order characterization of source inputs to the atmosphere of the Puget Sound. Both biomarker ratios and a principal component analysis confirmed regional data from the Puget Sound and Straits of Georgia region and pointed to the predominance of biomass and fossil fuel (mostly liquid petroleum products such

Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

Energy Technology Data Exchange (ETDEWEB)

Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

2009-03-01

In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

Analysis of acoustic sound signal for ONB measurement

International Nuclear Information System (INIS)

Park, S. J.; Kim, H. I.; Han, K. Y.; Chai, H. T.; Park, C.

2003-01-01

The onset of nucleate boiling (ONB) was measured in a test fuel bundle composed of several fuel element simulators (FES) by analysing the aquatic sound signals. In order measure ONBs, a hydrophone, a pre-amplifier, and a data acquisition system to acquire/process the aquatic signal was prepared. The acoustic signal generated in the coolant is converted to the current signal through the microphone. When the signal is analyzed in the frequency domain, each sound signal can be identified according to its origin of sound source. As the power is increased to a certain degree, a nucleate boiling is started. The frequent formation and collapse of the void bubbles produce sound signal. By measuring this sound signal one can pinpoint the ONB. Since the signal characteristics is identical for different mass flow rates, this method can be applicable for ascertaining ONB

Influence of air mass source sector on variations in CO2 mixing ratio at a boreal site in northern Finland

International Nuclear Information System (INIS)

Aalto, T.; Hatakka, J.; Viisanen, Y.

2003-01-01

CO 2 mixing ratio in air masses coming from different source sectors was studied at Pallas measurement station in Lapland. Source sectors were defined using back trajectories and wind direction measurements. Air masses from the North and West sectors showed an annual variation of 17 ppm, possibly affected by a long range transported marine air. A larger variation of 20 ppm was observed in air masses from the more continental South and East sectors. During late autumn mixing ratios in air masses from the South sector were high in comparison with the other sectors. Different methods for a source sector definition were considered for the site, located in a contoured terrain. 52%-73% of wind direction-based source sector definitions agreed with trajectory- based definitions. However, the number of cases with reliable sector definitions may remain low when considering all observations. Different definition methods can cause differences of the order of 1 ppm in sectorially selected monthly mean CO 2 mixing ratios. (orig.)

Sound field reconstruction based on the acousto-optic effect

DEFF Research Database (Denmark)

Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

2011-01-01

be measured with a laser Doppler vibrometer; furthermore, it can be exploited to characterize an arbitrary sound field using tomographic techniques. This paper briefly reviews the fundamental principles governing the acousto-optic effect in air, and presents an investigation of the tomographic reconstruction...... within the audible frequency range by means of simulations and experimental results. The good agreement observed between simulations and measurements is further confirmed with representations of the sound field obtained with traditional microphone array measurements....

Sound absorption of a new oblique-section acoustic metamaterial with nested resonator

Science.gov (United States)

Gao, Nansha; Hou, Hong; Zhang, Yanni; Wu, Jiu Hui

2018-02-01

This study designs and investigates high-efficiency sound absorption of new oblique-section nested resonators. Impedance tube experiment results show that different combinations of oblique-section nest resonators have tunable low-frequency bandwidth characteristics. The sound absorption mechanism is due to air friction losses in the slotted region and the sample structure resonance. The acousto-electric analogy model demonstrates that the sound absorption peak and bandwidth can be modulated over an even wider frequency range by changing the geometric size and combinations of structures. The proposed structure can be easily fabricated and used in low-frequency sound absorption applications.

Aerosol concentration measurements and correlations with air mass trajectories at the Pierre Auger Observatory

Science.gov (United States)

Micheletti, M. I.; Louedec, K.; Freire, M.; Vitale, P.; Piacentini, R. D.

2017-06-01

Aerosols play an important role in radiative transfer processes involved in different fields of study. In particular, their influence is crucial in the attenuation of light at astronomical and astrophysical observatories, and has to be taken into account in light transfer models employed to reconstruct the signals. The Andean Argentinean region is increasingly being considered as a good candidate to host such facilities, as well as the ones for solar-energy resources, and an adequate knowledge of aerosols characteristics there is needed, but it is not always possible due to the vast area involved and the scarce atmospheric data at ground. The aim of this work is to find correlations between aerosol data and particle trajectories that can give an insight into the origin and behaviour of aerosols in this zone and can be employed in situations in which one does not have local aerosol measurements. For this purpose, an aerosol spectrometer and dust monitor (Grimm 1.109) was installed at the Pierre Auger Observatory of ultra-high-energy cosmic rays, to record aerosol concentrations in different size intervals, at surface level. These measurements are analysed and correlated with air mass trajectories obtained from HYSPLIT (NOAA) model calculations. High aerosol concentrations are registered predominantly when air masses have travelled mostly over continental areas, mainly from the NE direction, while low aerosol concentrations are found in correspondence with air masses coming from the Pacific Ocean, from the NW direction. Different size distribution patterns were found for the aerosols depending on their origin: marine or continental. This work shows for the first time the size distribution of aerosols registered at the Pierre Auger Observatory. The correlations found between mass and particle concentrations (total and for different size ranges) and HYSPLIT air mass trajectories, confirm that the latter can be employed as a useful tool to infer the sources, evolution

Spatial variability of hailfalls in France: an analysis of air mass retro-trajectories

Science.gov (United States)

Hermida, Lucía; Merino, Andrés; Sánchez, José Luis; Berthet, Claude; Dessens, Jean; López, Laura; Fernández-González, Sergio; Gascón, Estíbaliz; García-Ortega, Eduardo

2014-05-01

Hail is the main meteorological risk in south-west France, with the strongest hailfalls being concentrated in just a few days. Specifically, this phenomenon occurs most often and with the greatest severity in the Midi-Pyrénées area. Previous studies have revealed the high spatial variability of hailfall in this part of France, even leading to different characteristics being recorded on hailpads that were relatively close together. For this reason, an analysis of the air mass trajectories was carried out at ground level and at altitude, which subsequently led to the formation of the hail recorded by these hailpads. It is already known that in the study zone, the trajectories of the storms usually stretch for long distances and are oriented towards the east, leading to hailstones with diameters in excess of 3 cm, and without any change in direction above 3 km. We analysed different days with hail precipitation where there was at least one stone with a diameter of 3 cm or larger. Using the simulations from these days, an analysis of the backward trajectories of the air masses was carried out. We used the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) to determine the origin of the air masses, and tracked them toward each of the hailpads that were hit during the day studied. The height of the final points was the height of the impacted hailpads. Similarly, the backward trajectories for different heights were also established. Finally, the results show how storms that affect neighbouring hailpads come from very different air masses; and provide a deeper understanding of the high variability that affects the characteristics of hailfalls. Acknowledgements The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2. This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22).

''Anomalous'' air showers from point sources: Mass limits and light curves

International Nuclear Information System (INIS)

Domokos, G.; Elliott, B.; Kovesi-Domokos, S.

1993-01-01

We describe a method to obtain upper limits on the mass of the primaries of air showers associated with point sources. One also obtains the UHE pulse shape of a pulsar if its period is observed in the signal. As an example, we analyze the data obtained during a recent burst of Hercules-X1

Evolution of charged species in propane/air flames: mass-spectrometric analysis and modelling

International Nuclear Information System (INIS)

Rodrigues, J M; Agneray, A; Jaffrezic, X; Bellenoue, M; Labuda, S; Leys, C; Chernukho, A P; Migoun, A N; Cenian, A; Savel'ev, A M; Titova, N S; Starik, A M

2007-01-01

Experimental and modelling studies of ion formation during combustion of propane/air mixtures are presented. The positive and negative ions mass/charge spectra in propane/air stoichiometric flame at atmospheric pressure are recorded in the range from 0 to 512 atomic mass units. The C 2 H 3 O + and HCO 2 - ions are found to be the most abundant ionic species in the flame front region. By increasing the distance from the flame front the ion composition changes significantly. In the burnt gas region the H 3 O + , NO + , CO 3 - , HCO 3 - ions are found to be the major charged species. To explain the experimental results the extended kinetic model describing the ion formation in flame and in the extraction system of the mass-spectrometer as well as ion-soot interaction is developed. It is shown that the ionic clusters, which are observed experimentally, form during the adiabatic expansion in the extraction system, and the presence of soot particles may change the total positive and negative ion concentrations in the gas phase

Reading drift in flow rate sensors caused by steady sound waves

International Nuclear Information System (INIS)

Maximiano, Celso; Nieble, Marcio D.; Migliavacca, Sylvana C.P.; Silva, Eduardo R.F.

1995-01-01

The use of thermal sensors very common for the measurement of small flows of gases. In this kind of sensor a little tube forming a bypass is heated symmetrically, then the temperature distribution in the tube modifies with the mass flow along it. When a stationary wave appears in the principal tube it causes an oscillation of pressure around the average value. The sensor, located between two points of the principal tube, indicates not only the principal mass flow, but also that one caused by the difference of pressure induced by the sound wave. When the gas flows at low pressures the equipment indicates a value that do not correspond to the real. Tests and essays were realized by generating a sound wave in the principal tube, without mass flow, and the sensor detected flux. In order to solve this problem a wave-damper was constructed, installed and tested in the system and it worked satisfactory eliminating with efficiency the sound wave. (author). 2 refs., 3 figs

33 CFR 334.770 - Gulf of Mexico and St. Andrew Sound, south of East Bay, Fla., Tyndall Drone Launch Corridor...

Science.gov (United States)

2010-07-01

... Sound, south of East Bay, Fla., Tyndall Drone Launch Corridor, Tyndall Air Force Base, Fla.; restricted.... Andrew Sound, south of East Bay, Fla., Tyndall Drone Launch Corridor, Tyndall Air Force Base, Fla... referred to as the “Tyndall Drone Launch Corridor.” (b) The regulations. (1) Military usage of areas is...

Speed of Sound in Hadronic matter using Non-extensive Statistics

CERN Document Server

Khuntia, Arvind; Garg, Prakhar; Sahoo, Raghunath; Cleymans, Jean

2016-01-01

The speed of sound ($c_s$) is studied to understand the hydrodynamical evolution of the matter created in heavy-ion collisions. The quark gluon plasma (QGP) formed in heavy-ion collisions evolves from an initial QGP to the hadronic phase via a possible mixed phase. Due to the system expansion in a first order phase transition scenario, the speed of sound reduces to zero as the specific heat diverges. We study the speed of sound for systems, which deviate from a thermalized Boltzmann distribution using non-extensive Tsallis statistics. In the present work, we calculate the speed of sound as a function of temperature for different $q$-values for a hadron resonance gas. We observe a similar mass cut-off behaviour in non-extensive case for $c^{2}_s$ by including heavier particles, as is observed in the case of a hadron resonance gas following equilibrium statistics. Also, we explicitly present that the temperature where the mass cut-off starts, varies with the $q$-parameter which hints at a relation between the d...

Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

Directory of Open Access Journals (Sweden)

J.-M. Diesch

2012-04-01

Full Text Available Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W. As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM₁ and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM₁ was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS. Gas phase analyzers monitored various trace gases (O₃, SO₂, NO, NO₂, CO₂ and a weather station provided meteorological parameters.

Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m⁻³ and 1000 cm⁻³. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM₁-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54% was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of

Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

Science.gov (United States)

Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

2012-04-01

Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM1) was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions, could be identified in the particle phase

Sound

CERN Document Server

Robertson, William C

2003-01-01

Muddled about what makes music? Stuck on the study of harmonics? Dumbfounded by how sound gets around? Now you no longer have to struggle to teach concepts you really don t grasp yourself. Sound takes an intentionally light touch to help out all those adults science teachers, parents wanting to help with homework, home-schoolers seeking necessary scientific background to teach middle school physics with confidence. The book introduces sound waves and uses that model to explain sound-related occurrences. Starting with the basics of what causes sound and how it travels, you'll learn how musical instruments work, how sound waves add and subtract, how the human ear works, and even why you can sound like a Munchkin when you inhale helium. Sound is the fourth book in the award-winning Stop Faking It! Series, published by NSTA Press. Like the other popular volumes, it is written by irreverent educator Bill Robertson, who offers this Sound recommendation: One of the coolest activities is whacking a spinning metal rod...

Thump, ring: the sound of a bouncing ball

International Nuclear Information System (INIS)

Katz, J I

2010-01-01

A basketball bounced on a stiff surface produces a characteristic loud thump, followed by a high-pitched ringing. Describing the ball as an inextensible but flexible membrane containing compressed air, I formulate an approximate theory of the generation of these sounds and predict their amplitudes and waveforms.

Thump, ring: the sound of a bouncing ball

Energy Technology Data Exchange (ETDEWEB)

Katz, J I, E-mail: katz@wuphys.wustl.ed [Department of Physics and McDonnell Center for the Space Sciences, Washington University, St Louis, MO 63130 (United States)

2010-07-15

A basketball bounced on a stiff surface produces a characteristic loud thump, followed by a high-pitched ringing. Describing the ball as an inextensible but flexible membrane containing compressed air, I formulate an approximate theory of the generation of these sounds and predict their amplitudes and waveforms.

The measurement of low air flow velocities

NARCIS (Netherlands)

Aghaei, A.; Mao, X.G.; Zanden, van der A.J.J.; Schaik, W.H.J.; Hendriks, N.A.

2005-01-01

Air flow velocity is measured with an acoustic sensor, which can be used especially for measuring low air flow velocities as well as the temperature of the air simultaneously. Two opposite transducers send a sound pulse towards each other. From the difference of the transit times, the air flow

A Comparison of the Red Green Blue (RGB) Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles and NOAA G-IV Dropsondes

Science.gov (United States)

Berndt, Emily; Folmer, Michael; Dunion, Jason

2014-01-01

RGB air mass imagery is derived from multiple channels or paired channel differences. The combination of channels and channel differences means the resulting imagery does not represent a quantity or physical parameter such as brightness temperature in conventional single channel imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles and NOAA G-IV dropsondes provide insight about the vertical structure of the air mass represented on the RGB air mass imagery and are a first step to validating the imagery.

Mass Spectrometer Sounding of the Turbopause Region on Commercial Vehicles

Science.gov (United States)

Thurairajah, B.; Bailey, S. M.; Syrstad, E. A.; Fish, C. S.; Siskind, D. E.; Russell, J. M.

2013-12-01

The turbopause region near 100 km remains one of the most poorly explored yet crucial regions of the upper atmosphere. In the vicinity of this altitude, the atmosphere reaches its lowest temperature and changes from being well mixed to being in diffusive equilibrium. Dynamical energy in the form of tides as well as gravity and planetary waves propagate from the lower atmosphere up to the ionosphere and thermosphere. Some energy and reactive chemical species are transported down across the turbopause to lower altitudes where the impact is significant. There is a significant dearth of composition observations near the turbopause. Few measurement techniques work well at this altitude, and it is too low for satellite orbits. Amazingly, major species with relatively large abundances such as O2, O, and CO2 are all poorly understood at these attitudes. While there are several experiments that measure temperature, the uncertainties in the temperature measurements are large because the techniques that are used rely on knowledge of CO2 or sometimes of O2. The lack of composition information thus hinders those observations that do occur near the turbopause and mesopause and leaves us with an overall poor understanding of this altitude region. We are soon to enter a new era in space exploration. Routine visits to the 100km region by commercial vehicles are on the verge of becoming a reality. The relevant organizations have expressed a willingness and even enthusiasm for including scientific instrumentation with their tourism and related commercial goals. We propose a major step forward in understanding the turbopause region by developing a mass spectrometer capable of being manifested on these commercial vehicles. Such an implantation could ultimately result in daily sounding of the turbopause region and greatly expand the database of measurements there. Our suggested instrument is a cryogenic time-of-flight mass Spectrometer. This technique has heritage, and our

Analysis of volatile compounds by open-air ionization mass spectrometry.

Science.gov (United States)

Meher, Anil Kumar; Chen, Yu-Chie

2017-05-08

This study demonstrates a simple method for rapid and in situ identification of volatile and endogenous compounds in culinary spice samples through mass spectrometry (MS). This method only requires a holder for solid spice sample (2-3 mm) that is placed close to a mass spectrometer inlet, which is applied with a high voltage. Volatile species responsible for the aroma of the spice samples can be readily detected by the mass spectrometer. Sample pretreatment is not required prior to MS analysis, and no solvent was used during MS analysis. The high voltage applied to the inlet of the mass spectrometer induces the ionization of volatile compounds released from the solid spice samples. Furthermore, moisture in the air also contributes to the ionization of volatile compounds. Dried spices including cinnamon and cloves are used as the model sample to demonstrate this straightforward MS analysis, which can be completed within few seconds. Furthermore, we also demonstrate the suitability of the current method for rapid screening of cinnamon quality through detection of the presence of a hepatotoxic agent, i.e. coumarin. Copyright © 2017 Elsevier B.V. All rights reserved.

Bending sound in graphene: Origin and manifestation

Energy Technology Data Exchange (ETDEWEB)

Adamyan, V.M., E-mail: vadamyan@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Bondarev, V.N., E-mail: bondvic@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Zavalniuk, V.V., E-mail: vzavalnyuk@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Department of Fundamental Sciences, Odessa Military Academy, 10 Fontanska Road, Odessa 65009 (Ukraine)

2016-11-11

Highlights: • The origin of sound-like dispersion of graphene bending mode is disclosed. • The speed of graphene bending sound is determined. • The renormalized graphene bending rigidity is derived. • The intrinsic corrugations of graphene are estimated. - Abstract: It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

Bending sound in graphene: Origin and manifestation

International Nuclear Information System (INIS)

Adamyan, V.M.; Bondarev, V.N.; Zavalniuk, V.V.

2016-01-01

Highlights: • The origin of sound-like dispersion of graphene bending mode is disclosed. • The speed of graphene bending sound is determined. • The renormalized graphene bending rigidity is derived. • The intrinsic corrugations of graphene are estimated. - Abstract: It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

Direct Measurement of the Speed of Sound Using a Microphone and a Speaker

Science.gov (United States)

Gómez-Tejedor, José A.; Castro-Palacio, Juan C.; Monsoriu, Juan A.

2014-01-01

We present a simple and accurate experiment to obtain the speed of sound in air using a conventional speaker and a microphone connected to a computer. A free open source digital audio editor and recording computer software application allows determination of the time-of-flight of the wave for different distances, from which the speed of sound is…

Measurement of the resistivity of porous materials with an alternating air-flow method.

Science.gov (United States)

Dragonetti, Raffaele; Ianniello, Carmine; Romano, Rosario A

2011-02-01

Air-flow resistivity is a main parameter governing the acoustic behavior of porous materials for sound absorption. The international standard ISO 9053 specifies two different methods to measure the air-flow resistivity, namely a steady-state air-flow method and an alternating air-flow method. The latter is realized by the measurement of the sound pressure at 2 Hz in a small rigid volume closed partially by the test sample. This cavity is excited with a known volume-velocity sound source implemented often with a motor-driven piston oscillating with prescribed area and displacement magnitude. Measurements at 2 Hz require special instrumentation and care. The authors suggest an alternating air-flow method based on the ratio of sound pressures measured at frequencies higher than 2 Hz inside two cavities coupled through a conventional loudspeaker. The basic method showed that the imaginary part of the sound pressure ratio is useful for the evaluation of the air-flow resistance. Criteria are discussed about the choice of a frequency range suitable to perform simplified calculations with respect to the basic method. These criteria depend on the sample thickness, its nonacoustic parameters, and the measurement apparatus as well. The proposed measurement method was tested successfully with various types of acoustic materials.

Variability of aerosol, gaseous pollutants and meteorological characteristics associated with continental, urban and marine air masses at the SW Atlantic coast of Iberia

Science.gov (United States)

Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

2011-12-01

Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions could be identified in the particle phase. In all

Sound transmission through double cylindrical shells lined with porous material under turbulent boundary layer excitation

Science.gov (United States)

Zhou, Jie; Bhaskar, Atul; Zhang, Xin

2015-11-01

This paper investigates sound transmission through double-walled cylindrical shell lined with poroelastic material in the core, excited by pressure fluctuations due to the exterior turbulent boundary layer (TBL). Biot's model is used to describe the sound wave propagating in the porous material. Three types of constructions, bonded-bonded, bonded-unbonded and unbonded-unbonded, are considered in this study. The power spectral density (PSD) of the inner shell kinetic energy is predicted for two turbulent boundary layer models, different air gap depths and three types of polyimide foams, respectively. The peaks of the inner shell kinetic energy due to shell resonance, hydrodynamic coincidence and acoustic coincidence are discussed. The results show that if the frequency band over the ring frequency is of interest, an air gap, even if very thin, should exist between the two elastic shells for better sound insulation. And if small density foam has a high flow resistance, a superior sound insulation can still be maintained.

An Exploratory Analysis of Sound Field Characteristics using the Impulse Response in a Car Cabin

Directory of Open Access Journals (Sweden)

Yoshiharu Soeta

2018-03-01

Full Text Available Sound environments in cars are becoming quieter and receiving attention because of the prevalence of low-noise engines such as hybrid and electric engines and the manifestation of automated driving. Although the car cabin has potential as a listening space, its acoustic quality has not been examined in detail. The present study investigated sound field characteristics in the car cabin using acoustic parameters obtained by impulse response analysis. In particular, effects of the passenger position, open windows and the use of an air conditioner on acoustic parameters were investigated. The passenger position affected the sound strength at low frequencies. Rear seats, except for the rear central seat, had lower interaural correlation than the front seats, suggesting that rear seats have more diffused sound fields. The opening of windows and use of air conditioners attenuated the ratio of early- and late-arriving energy at high frequencies, suggesting a loss of clarity for music.

Southeast Atlantic Cloud Properties in a Multivariate Statistical Model - How Relevant is Air Mass History for Local Cloud Properties?

Science.gov (United States)

Fuchs, Julia; Cermak, Jan; Andersen, Hendrik

2017-04-01

This study aims at untangling the impacts of external dynamics and local conditions on cloud properties in the Southeast Atlantic (SEA) by combining satellite and reanalysis data using multivariate statistics. The understanding of clouds and their determinants at different scales is important for constraining the Earth's radiative budget, and thus prominent in climate-system research. In this study, SEA stratocumulus cloud properties are observed not only as the result of local environmental conditions but also as affected by external dynamics and spatial origins of air masses entering the study area. In order to assess to what extent cloud properties are impacted by aerosol concentration, air mass history, and meteorology, a multivariate approach is conducted using satellite observations of aerosol and cloud properties (MODIS, SEVIRI), information on aerosol species composition (MACC) and meteorological context (ERA-Interim reanalysis). To account for the often-neglected but important role of air mass origin, information on air mass history based on HYSPLIT modeling is included in the statistical model. This multivariate approach is intended to lead to a better understanding of the physical processes behind observed stratocumulus cloud properties in the SEA.

Speed of sound in hadronic matter using non-extensive Tsallis statistics

International Nuclear Information System (INIS)

Khuntia, Arvind; Sahoo, Pragati; Garg, Prakhar; Sahoo, Raghunath; Cleymans, Jean

2016-01-01

The speed of sound (c_s) is studied to understand the hydrodynamical evolution of the matter created in heavy-ion collisions. The quark-gluon plasma (QGP) formed in heavy-ion collisions evolves from an initial QGP to the hadronic phase via a possible mixed phase. Due to the system expansion in a first-order phase transition scenario, the speed of sound reduces to zero as the specific heat diverges. We study the speed of sound for systems which deviate from a thermalized Boltzmann distribution using non-extensive Tsallis statistics. In the present work, we calculate the speed of sound as a function of temperature for different q-values for a hadron resonance gas. We observe a similar mass cut-off behaviour in the non-extensive case for c"2_s by including heavier particles, as is observed in the case of a hadron resonance gas following equilibrium statistics. Also, we explicitly show that the temperature where the mass cut-off starts varies with the q-parameter which hints at a relation between the degree of non-equilibrium and the limiting temperature of the system. It is shown that for values of q above approximately 1.13 all criticality disappears in the speed of sound, i.e. the decrease in the value of the speed of sound, observed at lower values of q, disappears completely. (orig.)

Speed of sound in hadronic matter using non-extensive Tsallis statistics

Energy Technology Data Exchange (ETDEWEB)

Khuntia, Arvind; Sahoo, Pragati; Garg, Prakhar; Sahoo, Raghunath [Indian Institute of Technology Indore, Discipline of Physics, School of Basic Science, Simrol, M.P. (India); Cleymans, Jean [University of Cape Town, UCT-CERN Research Centre and Department of Physics, Rondebosch (South Africa)

2016-09-15

The speed of sound (c{sub s}) is studied to understand the hydrodynamical evolution of the matter created in heavy-ion collisions. The quark-gluon plasma (QGP) formed in heavy-ion collisions evolves from an initial QGP to the hadronic phase via a possible mixed phase. Due to the system expansion in a first-order phase transition scenario, the speed of sound reduces to zero as the specific heat diverges. We study the speed of sound for systems which deviate from a thermalized Boltzmann distribution using non-extensive Tsallis statistics. In the present work, we calculate the speed of sound as a function of temperature for different q-values for a hadron resonance gas. We observe a similar mass cut-off behaviour in the non-extensive case for c{sup 2}{sub s} by including heavier particles, as is observed in the case of a hadron resonance gas following equilibrium statistics. Also, we explicitly show that the temperature where the mass cut-off starts varies with the q-parameter which hints at a relation between the degree of non-equilibrium and the limiting temperature of the system. It is shown that for values of q above approximately 1.13 all criticality disappears in the speed of sound, i.e. the decrease in the value of the speed of sound, observed at lower values of q, disappears completely. (orig.)

Evaluating heat-related mortality in Korea by objective classifications of 'air masses'

Czech Academy of Sciences Publication Activity Database

Kyselý, Jan; Huth, Radan; Kim, J.

2010-01-01

Roč. 30, č. 10 (2010), s. 1484-1501 ISSN 0899-8418 R&D Projects: GA ČR GC205/07/J044 Institutional research plan: CEZ:AV0Z30420517 Keywords : weather type classifications * air masses * biometeorology * human mortality * South Korea Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.479, year: 2010

Interpretation of the U.S.A. oceanographer sounding and radon data over the Arabian Sea during June 1967

International Nuclear Information System (INIS)

Rao, Y.P.; Desai, B.N.

1974-01-01

U.S.A. 'Oceanographer' sounding and radon data during June 1967 have been discussed with reference to the synoptic charts. During the period 14 to 21 June, there was above the surface layer of maritime air, less moist air with nearly saturation adiabatic lapse from the south Arabian Sea instead of the dry continental air from northeast Africa and Arabia. The 'Oceanographer' soundings compare well with those at Bombay, if one keeps in mind the effect of the Ghats for the latter location. The radon data show that there was presence of the maritime air from across the equator, which had got mixed to some extent with continental air from northeast Africa and Arabia; the high radon values off Saurashtra-Konkan were not due to vertical mixing of the lower maritime air with the upper continental air (author)

Interpretation of the U.S.A. oceanographer sounding and radon data over the Arabian Sea during June 1967

International Nuclear Information System (INIS)

Rao, Y.P.; Desai, B.N.

1974-01-01

U.S.A. 'Oceanographer' sounding and radon data during June 1967 have been discussed with reference to the synoptic charts. During the period 14 to 21 June, there was above the surface layer of maritime air, less moist air with nearly saturation adiabatic lapse from the south Arabian Sea instead of the dry continental air from northeast Africa and Arabia. The 'Oceanographer' soundings compare well with those at Bombay, if one keeps in mind the effect of the Ghats for the latter location. The radon data show that there was presence of the maritime air from across the equator, which had got mixed to some extent with continental air from northeast Africa and Arabia; the high radon values off Saurashtra-Konkan were not due to vertical mixing of the lower maritime air with the upper continental air. (author)

An IR Sounding-Based Analysis of the Saharan Air Layer in North Africa

Science.gov (United States)

Nicholls, Stephen D.; Mohr, Karen I.

2018-01-01

captured by both AIRS and model analysis, but the former favor layers than are thinner than observations. Finally, further analysis of HYSPLIT trajectories revealed that fewer than 10% and 33% of all SAL back trajectories passed through regions with notable precipitation (>100 mm accumulated along the trajectory path) or Aerosol Optical Depth (AOD greater than 0.4, 75th percentile of AOD) on average, respectively. Trajectory analysis indicated that only 57% of Saharan and 24% of non-Saharan WMLs are definitively of Saharan origin (Saharan requirement: Two consecutive days in Sahara and 24 or more of those hours within 72 hours of detection). Non-SAL WMLs either originate from local-to-regionally generated residual layers or from mid-latitude air streams that do not linger over the Sahara for a sufficient time period. Initial analysis shows these non-SAL WMLs tend to be both notably cooler and slightly moister than their SAL counter parts. Continuing analysis will address what role Saharan and non-Saharan air masses characteristics may play on local and regional environmental conditions.

Reconstruction of sound source signal by analytical passive TR in the environment with airflow

Science.gov (United States)

Wei, Long; Li, Min; Yang, Debin; Niu, Feng; Zeng, Wu

2017-03-01

In the acoustic design of air vehicles, the time-domain signals of noise sources on the surface of air vehicles can serve as data support to reveal the noise source generation mechanism, analyze acoustic fatigue, and take measures for noise insulation and reduction. To rapidly reconstruct the time-domain sound source signals in an environment with flow, a method combining the analytical passive time reversal mirror (AP-TR) with a shear flow correction is proposed. In this method, the negative influence of flow on sound wave propagation is suppressed by the shear flow correction, obtaining the corrected acoustic propagation time delay and path. Those corrected time delay and path together with the microphone array signals are then submitted to the AP-TR, reconstructing more accurate sound source signals in the environment with airflow. As an analytical method, AP-TR offers a supplementary way in 3D space to reconstruct the signal of sound source in the environment with airflow instead of the numerical TR. Experiments on the reconstruction of the sound source signals of a pair of loud speakers are conducted in an anechoic wind tunnel with subsonic airflow to validate the effectiveness and priorities of the proposed method. Moreover the comparison by theorem and experiment result between the AP-TR and the time-domain beamforming in reconstructing the sound source signal is also discussed.

Environmental Sound Perception: Metadescription and Modeling Based on Independent Primary Studies

Directory of Open Access Journals (Sweden)

Stephen McAdams

2010-01-01

Full Text Available The aim of the study is to transpose and extend to a set of environmental sounds the notion of sound descriptors usually used for musical sounds. Four separate primary studies dealing with interior car sounds, air-conditioning units, car horns, and closing car doors are considered collectively. The corpus formed by these initial stimuli is submitted to new experimental studies and analyses, both for revealing metacategories and for defining more precisely the limits of each of the resulting categories. In a second step, the new structure is modeled: common and specific dimensions within each category are derived from the initial results and new investigations of audio features are performed. Furthermore, an automatic classifier based on two audio descriptors and a multinomial logistic regression procedure is implemented and validated with the corpus.

Statistical Analysis for Subjective and Objective Evaluations of Dental Drill Sounds.

Directory of Open Access Journals (Sweden)

Tomomi Yamada

Full Text Available The sound produced by a dental air turbine handpiece (dental drill can markedly influence the sound environment in a dental clinic. Indeed, many patients report that the sound of a dental drill elicits an unpleasant feeling. Although several manufacturers have attempted to reduce the sound pressure levels produced by dental drills during idling based on ISO 14457, the sound emitted by such drills under active drilling conditions may negatively influence the dental clinic sound environment. The physical metrics related to the unpleasant impressions associated with dental drill sounds have not been determined. In the present study, psychological measurements of dental drill sounds were conducted with the aim of facilitating improvement of the sound environment at dental clinics. Specifically, we examined the impressions elicited by the sounds of 12 types of dental drills in idling and drilling conditions using a semantic differential. The analysis revealed that the impressions of dental drill sounds varied considerably between idling and drilling conditions and among the examined drills. This finding suggests that measuring the sound of a dental drill in idling conditions alone may be insufficient for evaluating the effects of the sound. We related the results of the psychological evaluations to those of measurements of the physical metrics of equivalent continuous A-weighted sound pressure levels (LAeq and sharpness. Factor analysis indicated that impressions of the dental drill sounds consisted of two factors: "metallic and unpleasant" and "powerful". LAeq had a strong relationship with "powerful impression", calculated sharpness was positively related to "metallic impression", and "unpleasant impression" was predicted by the combination of both LAeq and calculated sharpness. The present analyses indicate that, in addition to a reduction in sound pressure level, refining the frequency components of dental drill sounds is important for creating a

Mass spectrometry of solid samples in open air using combined laser ionization and ambient metastable ionization

International Nuclear Information System (INIS)

He, X.N.; Xie, Z.Q.; Gao, Y.; Hu, W.; Guo, L.B.; Jiang, L.; Lu, Y.F.

2012-01-01

Mass spectrometry of solid samples in open air was carried out using combined laser ionization and metastable ionization time-of-flight mass spectrometry (LI-MI-TOFMS) in ambient environment for qualitative and semiquantitative (relative analyte information, not absolute information) analysis. Ambient metastable ionization using a direct analysis in realtime (DART) ion source was combined with laser ionization time-of-flight mass spectrometry (LI-TOFMS) to study the effects of combining metastable and laser ionization. A series of metallic samples from the National Institute of Standards and Technology (NIST 494, 495, 498, 499, and 500) and a pure carbon target were characterized using LI-TOFMS in open air. LI-MI-TOFMS was found to be superior to laser-induced breakdown spectroscopy (LIBS). Laser pulse energies between 10 and 200 mJ at the second harmonic (532 nm) of an Nd:YAG laser were applied in the experiment to obtain a high degree of ionization in plasmas. Higher laser pulse energy improves signal intensities of trace elements (such as Fe, Cr, Mn, Ni, Ca, Al, and Ag). Data were analyzed by numerically calculating relative sensitivity coefficients (RSCs) and limit of detections (LODs) from mass spectrometry (MS) and LIBS spectra. Different parameters, such as boiling point, ionization potential, RSC, LOD, and atomic weight, were shown to analyze the ionization and MS detection processes in open air.

Variability of Atmospheric Radon-222 and Secondary Aerosol Components in Accordance with Air Mass Transport Pathways at Jeju Island, Korea, during 2011-2014

International Nuclear Information System (INIS)

Bu, Jun-Oh; Song, Jung-Min; Kim, Won-Hyung; Kang, Chang-Hee; Chambers, Scott D.; Williams, Alastair G.; Lee, Chulkyu

2016-01-01

Real-time monitoring of hourly atmospheric Radon-222 concentration and three daily monitoring of the secondary aerosol components of PM_1_0 were performed throughout 2011-2014 at Gosan station, Jeju Island, in order to characterize their background levels and temporal variation. The annual mean radon and PM_1_0 mass concentrations were 2326 ± 1198 mBq/m"3 and 37.1 ± 19.5 μg/m"3, respectively. Based on cluster analyses of air mass back trajectories, the frequencies of air masses originating from continental China, the Korean Peninsula, and North Pacific Ocean routes were 53, 28, and 19%, respectively. When the air masses were transported to Jeju Island from continental China, the concentrations of radon and secondary aerosol components (nss-SO_4"2"-, NO_3"-, NH_4"+) were relatively high: 2577 mBq/m"3 and 14.4 μg/m"3, respectively. In cases when the air masses have moved from the Korean Peninsula, the corresponding concentrations were 2247 mBq/m"3 and 11.4 μg/m"3, respectively. On the other hand, when the air masses came from the North Pacific Ocean, their radon and secondary aerosol concentrations decreased much further, 1372 mBq/m"3 and 10.5 μg/m"3, respectively. Consequently, the variability of atmospheric radon concentrations at Gosan station might be characterized by synoptic changes in air mass fetch as well as diurnal changes in atmospheric mixing depth.

A lightweight low-frequency sound insulation membrane-type acoustic metamaterial

Directory of Open Access Journals (Sweden)

Kuan Lu

2016-02-01

Full Text Available A novel membrane-type acoustic metamaterial with a high sound transmission loss (STL at low frequencies (⩽500Hz was designed and the mechanisms were investigated by using negative mass density theory. This metamaterial’s structure is like a sandwich with a thin (thickness=0.25mm lightweight flexible rubber material within two layers of honeycomb cell plates. Negative mass density was demonstrated at frequencies below the first natural frequency, which results in the excellent low-frequency sound insulation. The effects of different structural parameters of the membrane on the sound-proofed performance at low frequencies were investigated by using finite element method (FEM. The numerical results show that, the STL can be modulated to higher value by changing the structural parameters, such as the membrane surface density, the unite cell film shape, and the membrane tension. The acoustic metamaterial proposed in this study could provide a potential application in the low-frequency noise insulation.

A lightweight low-frequency sound insulation membrane-type acoustic metamaterial

Science.gov (United States)

Lu, Kuan; Wu, Jiu Hui; Guan, Dong; Gao, Nansha; Jing, Li

2016-02-01

A novel membrane-type acoustic metamaterial with a high sound transmission loss (STL) at low frequencies (⩽500Hz) was designed and the mechanisms were investigated by using negative mass density theory. This metamaterial's structure is like a sandwich with a thin (thickness=0.25mm) lightweight flexible rubber material within two layers of honeycomb cell plates. Negative mass density was demonstrated at frequencies below the first natural frequency, which results in the excellent low-frequency sound insulation. The effects of different structural parameters of the membrane on the sound-proofed performance at low frequencies were investigated by using finite element method (FEM). The numerical results show that, the STL can be modulated to higher value by changing the structural parameters, such as the membrane surface density, the unite cell film shape, and the membrane tension. The acoustic metamaterial proposed in this study could provide a potential application in the low-frequency noise insulation.

Air mass origins by back trajectory analysis for evaluating atmospheric 210Pb concentrations at Rokkasho, Aomori, Japan

International Nuclear Information System (INIS)

Akata, N.; Kawabata, H.; Hasegawa, H.; Kondo, K.; Chikuchi, Y.; Hisamatsu, S.; Inaba, J.; Sato, T.

2009-01-01

Atmospheric concentrations of 210 Pb change with various factors such as meso-scale meteorological conditions. We have already reported the biweekly atmospheric 210 Pb concentrations in Rokkasho, Japan for 5 years and found that they had clear seasonal variations: low concentrations in summer and high values in winter to spring. To study the reasons for the seasonal variations, the origins of the air mass flowing to Rokkasho were analyzed by 3-D backward air mass trajectory analysis. Routes of the calculated trajectories were classified into four regions: northeastern and southeastern Asian Continent, sea and other regions. The atmospheric 210 Pb concentrations were well correlated with the frequency of the routes through the northeastern Asian Continent. A non-linear multiple regression analysis of the 210 Pb concentrations and the relative frequencies of the four routes showed good fitting of the predicted values to the observed ones, and indicated that the atmospheric 210 Pb concentrations in Rokkasho depended on the frequency of the air mass from the northeastern Asian Continent. (author)

Discordant effect of body mass index on bone mineral density and speed of sound

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Hagag Philippe

2003-07-01

Full Text Available Abstract Background Increased BMI may affect the determination of bone mineral density (BMD by dual X-ray absorptiometry (DXA and speed of sound (SOS measured across bones. Preliminary data suggest that axial SOS is less affected by soft tissue. The purpose of this study is to evaluate the effect of body mass index (BMI on BMD and SOS measured along bones. Methods We compared axial BMD determined by DXA with SOS along the phalanx, radius and tibia in 22 overweight (BMI > 27 kg/m2, and 11 lean (BMI = 21 kg/m2 postmenopausal women. Serum bone specific alkaline phosphatase and urinary deoxypyridinoline excretion determined bone turnover. Results Mean femoral neck – but not lumbar spine BMD was higher in the overweight – as compared with the lean group (0.70 ± 0.82, -0.99 ± 0.52, P P Conclusions The high BMI of postmenopausal women may result in spuriously high BMD. SOS measured along bones may be a more appropriate means for evaluating bones of overweight women.

Audible sound treatment of the microalgae Picochlorum oklahomensis for enhancing biomass productivity.

Science.gov (United States)

Cai, Weiming; Dunford, Nurhan Turgut; Wang, Ning; Zhu, Songming; He, Huinong

2016-02-01

It has been reported in the literature that exposure of microalgae cells to audible sound could promote growth. This study examined the effect of sound waves with the frequency of 1100 Hz, 2200 Hz, and 3300 Hz to stimulate the biomass productivity of an Oklahoma native strain, Picochlorum oklahomensis (PO). The effect of the frequency of sound on biomass mass was measured. This study demonstrated that audible sound treatment of the algae cultures at 2200 Hz was the most effective in terms of biomass production and volumetric oil yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of RASS temperature profiles with other tropospheric soundings

International Nuclear Information System (INIS)

Bonino, G.; Lombardini, P.P.; Trivero, P.

1980-01-01

The vertical temperature profile of the lower troposphere can be measured with a radio-acoustic sounding system (RASS). A comparison of the thermal profiles measured with the RASS and with traditional methods shows a) RASS ability to produce vertical thermal profiles at an altitude range of 170 to 1000 m with temperature accuracy and height discrimination comparable with conventional soundings, b) advantages of remote sensing as offered by new sounder, c) applicability of RASS both in assessing evolution of thermodynamic conditions in PBL and in sensing conditions conducive to high concentrations of air pollutants at the ground level. (author)

Variability of Atmospheric Radon-222 and Secondary Aerosol Components in Accordance with Air Mass Transport Pathways at Jeju Island, Korea, during 2011-2014

Energy Technology Data Exchange (ETDEWEB)

Bu, Jun-Oh; Song, Jung-Min; Kim, Won-Hyung; Kang, Chang-Hee [Jeju National University, Jeju (Korea, Republic of); Chambers, Scott D.; Williams, Alastair G. [Australian Nuclear Science and Technology Organisation, Kirrawee DC (Australia); Lee, Chulkyu [Korea Meteorological Administration, Seoul (Korea, Republic of)

2016-06-15

Real-time monitoring of hourly atmospheric Radon-222 concentration and three daily monitoring of the secondary aerosol components of PM{sub 10} were performed throughout 2011-2014 at Gosan station, Jeju Island, in order to characterize their background levels and temporal variation. The annual mean radon and PM{sub 10} mass concentrations were 2326 ± 1198 mBq/m{sup 3} and 37.1 ± 19.5 μg/m{sup 3}, respectively. Based on cluster analyses of air mass back trajectories, the frequencies of air masses originating from continental China, the Korean Peninsula, and North Pacific Ocean routes were 53, 28, and 19%, respectively. When the air masses were transported to Jeju Island from continental China, the concentrations of radon and secondary aerosol components (nss-SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, NH{sub 4}{sup +}) were relatively high: 2577 mBq/m{sup 3} and 14.4 μg/m{sup 3}, respectively. In cases when the air masses have moved from the Korean Peninsula, the corresponding concentrations were 2247 mBq/m{sup 3} and 11.4 μg/m{sup 3}, respectively. On the other hand, when the air masses came from the North Pacific Ocean, their radon and secondary aerosol concentrations decreased much further, 1372 mBq/m{sup 3} and 10.5 μg/m{sup 3}, respectively. Consequently, the variability of atmospheric radon concentrations at Gosan station might be characterized by synoptic changes in air mass fetch as well as diurnal changes in atmospheric mixing depth.

Sound Propagation in Gas-Vapor-Droplet Suspensions with Evaporation and Nonlinear Particle Relaxation

Science.gov (United States)

Kandula, Max

2012-01-01

The Sound attenuation and dispersion in saturated gas-vapor-droplet mixture in the presence of evaporation has been investigated theoretically. The theory is based on an extension of the work of Davidson to accommodate the effects of nonlinear particle relaxation processes of mass, momentum and energy transfer on sound attenuation and dispersion. The results indicate the existence of a spectral broadening effect in the attenuation coefficient (scaled with respect to the peak value) with a decrease in droplet mass concentration. It is further shown that for large values of the droplet concentration the scaled attenuation coefficient is characterized by a universal spectrum independent of droplet mass concentration.

Development of Optophone with No Diaphragm and Application to Sound Measurement in Jet Flow

Directory of Open Access Journals (Sweden)

Yoshito Sonoda

2012-01-01

Full Text Available The optophone with no diaphragm, which can detect sound waves without disturbing flow of air and sound field, is presented as a novel sound measurement technique and the present status of development is reviewed in this paper. The method is principally based on the Fourier optics and the sound signal is obtained by detecting ultrasmall diffraction light generated from phase modulation by sounds. The principle and theory, which have been originally developed as a plasma diagnostic technique to measure electron density fluctuations in the nuclear fusion research, are briefly introduced. Based on the theoretical analysis, property and merits as a wave-optical sound detection are presented, and the fundamental experiments and results obtained so far are reviewed. It is shown that sounds from about 100 Hz to 100 kHz can be simultaneously detected by a visible laser beam, and the method is very useful to sound measurement in aeroacoustics. Finally, present main problems of the optophone for practical uses in sound and/or noise measurements and the image of technology expected in the future are shortly shown.

Sound algorithms

OpenAIRE

De Götzen , Amalia; Mion , Luca; Tache , Olivier

2007-01-01

International audience; We call sound algorithms the categories of algorithms that deal with digital sound signal. Sound algorithms appeared in the very infancy of computer. Sound algorithms present strong specificities that are the consequence of two dual considerations: the properties of the digital sound signal itself and its uses, and the properties of auditory perception.

46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island...

Mass transfer characteristics of bisporus mushroom ( Agaricus bisporus) slices during convective hot air drying

Science.gov (United States)

Ghanbarian, Davoud; Baraani Dastjerdi, Mojtaba; Torki-Harchegani, Mehdi

2016-05-01

An accurate understanding of moisture transfer parameters, including moisture diffusivity and moisture transfer coefficient, is essential for efficient mass transfer analysis and to design new dryers or improve existing drying equipments. The main objective of the present study was to carry out an experimental and theoretical investigation of mushroom slices drying and determine the mass transfer characteristics of the samples dried under different conditions. The mushroom slices with two thicknesses of 3 and 5 mm were dried at air temperatures of 40, 50 and 60 °C and air flow rates of 1 and 1.5 m s-1. The Dincer and Dost model was used to determine the moisture transfer parameters and predict the drying curves. It was observed that the entire drying process took place in the falling drying rate period. The obtained lag factor and Biot number indicated that the moisture transfer in the samples was controlled by both internal and external resistance. The effective moisture diffusivity and the moisture transfer coefficient increased with increasing air temperature, air flow rate and samples thickness and varied in the ranges of 6.5175 × 10-10 to 1.6726 × 10-9 m2 s-1 and 2.7715 × 10-7 to 3.5512 × 10-7 m s-1, respectively. The validation of the Dincer and Dost model indicated a good capability of the model to describe the drying curves of the mushroom slices.

Mass and chemically speciated size distribution of Prague aerosol using an aerosol dryer - The influence of air mass origin

Czech Academy of Sciences Publication Activity Database

Schwarz, Jaroslav; Štefancová, Lucia; Maenhaut, W.; Smolík, Jiří; Ždímal, Vladimír

2012-01-01

Roč. 437, OCT 15 (2012), s. 348-362 ISSN 0048-9697 R&D Projects: GA ČR GA205/09/2055; GA ČR GAP209/11/1342; GA MŠk ME 941 Grant - others:SRF GU(BE) 01S01306 Institutional support: RVO:67985858 Keywords : atmospheric aerosols * mass size distribution * chemical composition Subject RIV: DI - Air Pollution ; Quality Impact factor: 3.258, year: 2012

Water gun vs air gun: A comparison

Science.gov (United States)

Hutchinson, D.R.; Detrick, R. S.

1984-01-01

The water gun is a relatively new marine seismic sound source that produces an acoustic signal by an implosive rather than explosive mechanism. A comparison of the source characteristics of two different-sized water guns with those of conventional air guns shows the the water gun signature is cleaner and much shorter than that of a comparable-sized air gun: about 60-100 milliseconds (ms) for an 80-in3. (1.31-liter (I)) water gun compared with several hundred ms for an 80-in3. (1.31-1) air gun. The source spectra of water guns are richer in high frequencies (>200 Hz) than are those of air guns, but they also have less energy than those of air guns at low frequencies. A comparison between water gun and air gun reflection profiles in both shallow (Long Island Sound)-and deep (western Bermuda Rise)-water settings suggests that the water gun offers a good compromise between very high resolution, limited penetration systems (e.g. 3.5-kHz profilers and sparkers) and the large volume air guns and tuned air gun arrays generally used where significant penetration is required. ?? 1984 D. Reidel Publishing Company.

Hearing with an atympanic ear: good vibration and poor sound-pressure detection in the royal python, Python regius.

Science.gov (United States)

Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian; Madsen, Peter Teglberg

2012-01-15

Snakes lack both an outer ear and a tympanic middle ear, which in most tetrapods provide impedance matching between the air and inner ear fluids and hence improve pressure hearing in air. Snakes would therefore be expected to have very poor pressure hearing and generally be insensitive to airborne sound, whereas the connection of the middle ear bone to the jaw bones in snakes should confer acute sensitivity to substrate vibrations. Some studies have nevertheless claimed that snakes are quite sensitive to both vibration and sound pressure. Here we test the two hypotheses that: (1) snakes are sensitive to sound pressure and (2) snakes are sensitive to vibrations, but cannot hear the sound pressure per se. Vibration and sound-pressure sensitivities were quantified by measuring brainstem evoked potentials in 11 royal pythons, Python regius. Vibrograms and audiograms showed greatest sensitivity at low frequencies of 80-160 Hz, with sensitivities of -54 dB re. 1 m s(-2) and 78 dB re. 20 μPa, respectively. To investigate whether pythons detect sound pressure or sound-induced head vibrations, we measured the sound-induced head vibrations in three dimensions when snakes were exposed to sound pressure at threshold levels. In general, head vibrations induced by threshold-level sound pressure were equal to or greater than those induced by threshold-level vibrations, and therefore sound-pressure sensitivity can be explained by sound-induced head vibration. From this we conclude that pythons, and possibly all snakes, lost effective pressure hearing with the complete reduction of a functional outer and middle ear, but have an acute vibration sensitivity that may be used for communication and detection of predators and prey.

Liquid phase mass production of air-stable black phosphorus/phospholipids nanocomposite with ultralow tunneling barrier

Science.gov (United States)

Zhang, Qiankun; Liu, Yinan; Lai, Jiawei; Qi, Shaomian; An, Chunhua; Lu, Yao; Duan, Xuexin; Pang, Wei; Zhang, Daihua; Sun, Dong; Chen, Jian-Hao; Liu, Jing

2018-04-01

Few-layer black phosphorus (FLBP), a recently discovered two-dimensional semiconductor, has attracted substantial attention in the scientific and technical communities due to its great potential in electronic and optoelectronic applications. However, reactivity of FLBP flakes with ambient species limits its direct applications. Among various methods to passivate FLBP in ambient environment, nanocomposites mixing FLBP flakes with stable matrix may be one of the most promising approaches for industry applications. Here, we report a simple one-step procedure to mass produce air-stable FLBP/phospholipids nanocomposite in liquid phase. The resultant nanocomposite is found to have ultralow tunneling barrier for charge carriers which can be described by an Efros-Shklovskii variable range hopping mechanism. Devices made from such mass-produced FLBP/phospholipids nanocomposite show highly stable electrical conductivity and opto-electrical response in ambient conditions, indicating its promising applications in both electronic and optoelectronic applications. This method could also be generalized to the mass production of nanocomposites consisting of other air-sensitive 2D materials, such as FeSe, NbSe2, WTe2, etc.

Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger

International Nuclear Information System (INIS)

Mothilal, T.; Pitchandi, K.

2015-01-01

Present work elaborates the effect of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in a cyclone heat exchanger. The RNG k-ε turbulence model was adopted for modeling high turbulence flow and Discrete phase model (DPM) to track solid particles in a cyclone heat exchanger by ANSYS FLUENT software. The effect of inlet air velocity (5 to 25 m/s) and inlet solid particle feed rate of (0.2 to 2.5 g/s) at different particle diameter (300 to 500 μm) on holdup mass and heat transfer rate in cyclone heat exchanger was studied at air inlet temperature of 473 K. Results show that holdup mass and heat transfer rate increase with increase in inlet air velocity and inlet solid particle feed rate. Influence of solid particle feed rate on holdup mass has more significance. Experimental setup was built for high efficiency cyclone. Good agreement was found between experimental and simulation pressure drop. Empirical correlation was derived for dimensionless holdup mass and Nusselt number based on CFD data by regression technique. Correlation predicts dimensional holdup mass with +5% to -8% errors of experimental data and Nusselt number with +9% to -3%

Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Mothilal, T. [T. J. S. Engineering College, Gummidipoond (India); Pitchandi, K. [Sri Venkateswara College of Engineering, Sriperumbudur (India)

2015-10-15

Present work elaborates the effect of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in a cyclone heat exchanger. The RNG k-ε turbulence model was adopted for modeling high turbulence flow and Discrete phase model (DPM) to track solid particles in a cyclone heat exchanger by ANSYS FLUENT software. The effect of inlet air velocity (5 to 25 m/s) and inlet solid particle feed rate of (0.2 to 2.5 g/s) at different particle diameter (300 to 500 μm) on holdup mass and heat transfer rate in cyclone heat exchanger was studied at air inlet temperature of 473 K. Results show that holdup mass and heat transfer rate increase with increase in inlet air velocity and inlet solid particle feed rate. Influence of solid particle feed rate on holdup mass has more significance. Experimental setup was built for high efficiency cyclone. Good agreement was found between experimental and simulation pressure drop. Empirical correlation was derived for dimensionless holdup mass and Nusselt number based on CFD data by regression technique. Correlation predicts dimensional holdup mass with +5% to -8% errors of experimental data and Nusselt number with +9% to -3%.

The evolution of air resonance power efficiency in the violin and its ancestors.

Science.gov (United States)

Nia, Hadi T; Jain, Ankita D; Liu, Yuming; Alam, Mohammad-Reza; Barnas, Roman; Makris, Nicholas C

2015-03-08

The fact that acoustic radiation from a violin at air-cavity resonance is monopolar and can be determined by pure volume change is used to help explain related aspects of violin design evolution. By determining the acoustic conductance of arbitrarily shaped sound holes, it is found that air flow at the perimeter rather than the broader sound-hole area dominates acoustic conductance, and coupling between compressible air within the violin and its elastic structure lowers the Helmholtz resonance frequency from that found for a corresponding rigid instrument by roughly a semitone. As a result of the former, it is found that as sound-hole geometry of the violin's ancestors slowly evolved over centuries from simple circles to complex f-holes, the ratio of inefficient, acoustically inactive to total sound-hole area was decimated, roughly doubling air-resonance power efficiency. F-hole length then slowly increased by roughly 30% across two centuries in the renowned workshops of Amati, Stradivari and Guarneri, favouring instruments with higher air-resonance power, through a corresponding power increase of roughly 60%. By evolution-rate analysis, these changes are found to be consistent with mutations arising within the range of accidental replication fluctuations from craftsmanship limitations with subsequent selection favouring instruments with higher air-resonance power.

Atmospheric pollutants in Chiang Mai (Thailand) over a five-year period (2005-2009), their possible sources and relation to air mass movement

Science.gov (United States)

Chantara, Somporn; Sillapapiromsuk, Sopittaporn; Wiriya, Wan

2012-12-01

Monitoring and analysis of the chemical composition of air pollutants were conducted over a five-year period (2005-2009) in the sub-urban area of Chiang Mai, Thailand. This study aims to determine the seasonal variation of atmospheric ion species and gases, examine their correlations, identify possible sources and assess major air-flow patterns to the receptor. The dominant gas and particulate pollutants were NH3 (43-58%) and SO42- (39-48%), respectively. The annual mean concentrations of NH3 (μg m-3) in descending order were 4.08 (2009) > 3.32 (2007) > 2.68 (2008) > 2.47 (2006) and 1.87 (2005), while those of SO42- (μg m-3) were 2.60 (2007) > 2.20 (2006) > 1.95 (2009) > 1.75 (2008) and 1.26 (2005). Concentrations of particulate ions were analyzed by principle component analysis to find out the possible sources of air pollutants in this area. The first component of each year had a high loading of SO42- and NH4+, which probably came from fuel combustion and agricultural activity, respectively. K+, a tracer of biomass burning, also contributed to the first or the second components of each year. Concentrations of NH4+ and SO42- were well correlated (r > 0.777, p Chiang Mai from 2005 to 2009 were analyzed using the hybrid single particle langrangian integrated trajectory (HYSPLIT) model and grouped by cluster analysis. The air mass data was analyzed for the dry season (n = 18; 100%). The trajectory of air mass in 2005 mainly originated locally (67%). In 2006, the recorded data showed that 56% of air mass was emitted from the western continental region of Thailand. In 2007, the percent ratios from the western and eastern continental areas were equal (39%). In 2008, 67% originated from the western continental area. In 2009, the recorded air mass mainly came from the western continental area (72%). In conclusion, the major trajectories of air mass from 2006 to 2009 originated from the southwest direction of the receptor, but in 2005, the air mass appeared to be locally

Columnar aerosol optical and radiative properties according to season and air mass transport pattern over East Asia.

Science.gov (United States)

Noh, Young M; Müller, Detlef; Lee, Hanlim; Lee, Kwonho; Kim, Young Joon

2012-08-01

The column-integrated optical and radiative properties of aerosols in the downwind area of East Asia were investigated based on sun/sky radiometer measurements performed from February 2004 to June 2005 at Gwangju (35.23° N, 126.84° E) and Anmyeon (36.54° N, 126.33° E), Korea. The observed aerosol data were analyzed for differences among three seasons: spring (March-May), summer (June-August), and autumn/winter (September-February). The data were also categorized into five types depending on the air mass origin in arriving in the measurement sites: (a) from a northerly direction in spring (S(N)), (b) from a westerly direction in spring (S(W)), (c) cases with a low Ångström exponent (air mass origin. The forcing efficiency in summer was -131.7 and -125.6 W m(-2) at the surface in Gwangju and Anmyeon, respectively. These values are lower than those under the atmospheric conditions of spring and autumn/winter. The highest forcing efficiencies in autumn/winter were -214.3 and -255.9 W m(-2) at the surface in Gwangju and Anmyeon, respectively, when the air mass was transported from westerly directions.

Relation of air mass history to nucleation events in Po Valley, Italy, using back trajectories analysis

Directory of Open Access Journals (Sweden)

L. Sogacheva

2007-01-01

Full Text Available In this paper, we study the transport of air masses to San Pietro Capofiume (SPC in Po Valley, Italy, by means of back trajectories analysis. Our main aim is to investigate whether air masses originate over different regions on nucleation event days and on nonevent days, during three years when nucleation events have been continuously recorded at SPC. The results indicate that nucleation events occur frequently in air masses arriving from Central Europe, whereas event frequency is much lower in the air transported from southern directions and from the Atlantic Ocean. We also analyzed the behaviour of meteorological parameters during 96 h transport to SPC, and found that, on average, event trajectories undergo stronger subsidence during the last 12 h before the arrival at SPC than nonevent trajectories. This causes a reversal in the temperature and relative humidity (RH differences between event and nonevent trajectories: between 96 and 12 h back time, temperature is lower and RH is higher for event than nonevent trajectories and between 12 and 0 h vice versa. Boundary layer mixing is stronger along the event trajectories compared to nonevent trajectories. The absolute humidity (AH is similar for the event and nonevent trajectories between about 96 h and about 60 h back time, but after that, the event trajectories AH becomes lower due to stronger rain. We also studied transport of SO2 to SPC, and conclude that although sources in Po Valley most probably dominate the measured concentrations, certain Central and Eastern European sources also make a substantial contribution.

Characterization of key aerosol, trace gas and meteorological properties and particle formation and growth processes dependent on air mass origins in coastal Southern Spain

Science.gov (United States)

Diesch, J.; Drewnick, F.; Sinha, V.; Williams, J.; Borrmann, S.

2011-12-01

The chemical composition and concentration of aerosols at a certain site can vary depending on season, the air mass source region and distance from sources. Regardless of the environment, new particle formation (NPF) events are one of the major sources for ultrafine particles which are potentially hazardous to human health. Grown particles are optically active and efficient CCN resulting in important implications for visibility and climate (Zhang et al., 2004). The study presented here is intended to provide information about various aspects of continental, urban and marine air masses reflected by wind patterns of the air arriving at the measurement site. Additionally we will be focusing on NPF events associated with different types of air masses affecting their emergence and temporal evolution. Measurements of the ambient aerosol, various trace gases and meteorological parameters were performed within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from mid-November to mid-December 2008 at the atmospheric research station "El Arenosillo" located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean. Number and mass as well as PAH and black carbon concentrations were measured in PM1 and size distribution instruments covered the size range 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (AMS). In order to evaluate the characteristics of different air masses linking local and regional sources as well as NPF processes, characteristic air mass types were classified dependent on backwards trajectory pathways and local meteorology. Large nuclei mode concentrations in the number size distribution were found within continental and urban influenced air mass types due to frequently occurring NPF events. Exploring individual production and sink variables, sulfuric

The natural history of sound localization in mammals--a story of neuronal inhibition.

Science.gov (United States)

Grothe, Benedikt; Pecka, Michael

2014-01-01

Our concepts of sound localization in the vertebrate brain are widely based on the general assumption that both the ability to detect air-borne sounds and the neuronal processing are homologous in archosaurs (present day crocodiles and birds) and mammals. Yet studies repeatedly report conflicting results on the neuronal circuits and mechanisms, in particular the role of inhibition, as well as the coding strategies between avian and mammalian model systems. Here we argue that mammalian and avian phylogeny of spatial hearing is characterized by a convergent evolution of hearing air-borne sounds rather than by homology. In particular, the different evolutionary origins of tympanic ears and the different availability of binaural cues in early mammals and archosaurs imposed distinct constraints on the respective binaural processing mechanisms. The role of synaptic inhibition in generating binaural spatial sensitivity in mammals is highlighted, as it reveals a unifying principle of mammalian circuit design for encoding sound position. Together, we combine evolutionary, anatomical and physiological arguments for making a clear distinction between mammalian processing mechanisms and coding strategies and those of archosaurs. We emphasize that a consideration of the convergent nature of neuronal mechanisms will significantly increase the explanatory power of studies of spatial processing in both mammals and birds.

The effect of long-range air mass transport pathways on PM10 and NO2 concentrations at urban and rural background sites in Ireland: Quantification using clustering techniques.

Science.gov (United States)

Donnelly, Aoife A; Broderick, Brian M; Misstear, Bruce D

2015-01-01

The specific aims of this paper are to: (i) quantify the effects of various long range transport pathways nitrogen dioxide (NO2) and particulate matter with diameter less than 10μm (PM10) concentrations in Ireland and identify air mass movement corridors which may lead to incidences poor air quality for application in forecasting; (ii) compare the effects of such pathways at various sites; (iii) assess pathways associated with a period of decreased air quality in Ireland. The origin of and the regions traversed by an air mass 96h prior to reaching a receptor is modelled and k-means clustering is applied to create air-mass groups. Significant differences in air pollution levels were found between air mass cluster types at urban and rural sites. It was found that easterly or recirculated air masses lead to higher NO2 and PM10 levels with average NO2 levels varying between 124% and 239% of the seasonal mean and average PM10 levels varying between 103% and 199% of the seasonal mean at urban and rural sites. Easterly air masses are more frequent during winter months leading to higher overall concentrations. The span in relative concentrations between air mass clusters is highest at the rural site indicating that regional factors are controlling concentration levels. The methods used in this paper could be applied to assist in modelling and forecasting air quality based on long range transport pathways and forecast meteorology without the requirement for detailed emissions data over a large regional domain or the use of computationally demanding modelling techniques.

Theoretical investigation of the sound attenuation of membrane-type acoustic metamaterials

International Nuclear Information System (INIS)

Zhang, Yuguang; Wen, Jihong; Xiao, Yong; Wen, Xisen; Wang, Jianwei

2012-01-01

Membrane-type acoustic metamaterials have been recently shown to exhibit good performance of sound attenuation in a low frequency range. An analytical approach for the fast calculation of sound transmission loss of the membrane-type acoustic metamaterials is presented here. The discussion indicate that the first transmission loss valley and the transmission loss peak depend strongly on the attaching mass, while the second transmission loss valley is mainly influenced by the membrane properties. The effects of membrane tension and mass position on the transmission loss and characteristic frequencies are also discussed in detail. -- Highlights: ► An analytical approach was presented here. ► First TL valley and peak depend strongly on attaching mass. ► Second TL valley is mainly influenced by properties of membrane. ► TL peak move to low frequency at a special position keeping TL valley motionless.

Learning about the Dynamic Sun through Sounds

Science.gov (United States)

Quinn, M.; Peticolas, L. M.; Luhmann, J.; MacCallum, J.

2008-06-01

Can we hear the Sun or its solar wind? Not in the sense that they make sound. But we can take the particle, magnetic field, electric field, and image data and turn it into sound to demonstrate what the data tells us. We present work on turning data from the two-satellite NASA mission called STEREO (Solar TErrestrial RElations Observatory) into sounds and music (sonification). STEREO has two satellites orbiting the Sun near Earth's orbit to study the coronal mass ejections (CMEs) from the Corona. One sonification project aims to inspire musicians, museum patrons, and the public to learn more about CMEs by downloading STEREO data and using it to make music. We demonstrate the software and discuss the way in which it was developed. A second project aims to produce a museum exhibit using STEREO imagery and sounds from STEREO data. We demonstrate a "walk across the Sun" created for this exhibit so people can hear the features on solar images. We show how pixel intensity translates into pitches from selectable scales with selectable musical scale size and octave locations. We also share our successes and lessons learned.

Cloud Water Content Sensor for Sounding Balloons and Small UAVs

Science.gov (United States)

Bognar, John A.

2009-01-01

A lightweight, battery-powered sensor was developed for measuring cloud water content, which is the amount of liquid or solid water present in a cloud, generally expressed as grams of water per cubic meter. This sensor has near-zero power consumption and can be flown on standard sounding balloons and small, unmanned aerial vehicles (UAVs). The amount of solid or liquid water is important to the study of atmospheric processes and behavior. Previous sensing techniques relied on strongly heating the incoming air, which requires a major energy input that cannot be achieved on sounding balloons or small UAVs.

Resonant modal group theory of membrane-type acoustical metamaterials for low-frequency sound attenuation

Science.gov (United States)

Ma, Fuyin; Wu, Jiu Hui; Huang, Meng

2015-09-01

In order to overcome the influence of the structural resonance on the continuous structures and obtain a lightweight thin-layer structure which can effectively isolate the low-frequency noises, an elastic membrane structure was proposed. In the low-frequency range below 500 Hz, the sound transmission loss (STL) of this membrane type structure is greatly higher than that of the current sound insulation material EVA (ethylene-vinyl acetate copo) of vehicle, so it is possible to replace the EVA by the membrane-type metamaterial structure in practice engineering. Based on the band structure, modal shapes, as well as the sound transmission simulation, the sound insulation mechanism of the designed membrane-type acoustic metamaterials was analyzed from a new perspective, which had been validated experimentally. It is suggested that in the frequency range above 200 Hz for this membrane-mass type structure, the sound insulation effect was principally not due to the low-level locally resonant mode of the mass block, but the continuous vertical resonant modes of the localized membrane. So based on such a physical property, a resonant modal group theory is initially proposed in this paper. In addition, the sound insulation mechanism of the membrane-type structure and thin plate structure were combined by the membrane/plate resonant theory.

Research on mass transfer and actual performance of the membrane regeneration air-conditioning system

International Nuclear Information System (INIS)

Li, Xiu-Wei; Zhang, Xiao-Song; Chen, Qing

2015-01-01

Highlights: • Experimental research has been made on the membrane air-conditioning system. • We develop mass transfer models for the membrane regeneration process. • The paper exposes the actual performance of the system. • Increase of membrane pairs improves the performance. - Abstract: Absorption air-conditioning system has great advantages in energy conservation and environmental protection. To improve the performance of the traditional system, the membrane regeneration absorption system was proposed. Its COP could approach 6 by regenerating absorbent solution with the ion exchange membranes. However, the theoretical conclusion has not been supported by the experiment. This paper presents the experimental research of the membrane regeneration process. It has investigated the mass transfer process, energy efficiency and actual performance under different working conditions. Based on that, a mass transfer model has been developed and the influences of some key parameters have been exposed. It found the regeneration performance is mainly influenced by the current intensity. The calculation results with the model agree well the experimental data. The actual efficiency was lower than 50%, caused by energy loss in heat and electrochemical reactions. The actual COP is between 1 and 3, lower current intensity and more membrane pairs could improve it.

Transport Regimes of Air Masses Affecting the Tropospheric Composition of the Canadian and European Arctic During RACEPAC 2014 and NETCARE 2014/2015

Science.gov (United States)

Bozem, H.; Hoor, P. M.; Koellner, F.; Kunkel, D.; Schneider, J.; Schulz, C.; Herber, A. B.; Borrmann, S.; Wendisch, M.; Ehrlich, A.; Leaitch, W. R.; Willis, M. D.; Burkart, J.; Thomas, J. L.; Abbatt, J.

2015-12-01

The Arctic is warming much faster than any other place in the world and undergoes a rapid change dominated by a changing climate in this region. The impact of polluted air masses traveling to the Arctic from various remote sources significantly contributes to the observed climate change, in contrast there are additional local emission sources contributing to the level of pollutants (trace gases and aerosol). Processes affecting the emission and transport of these pollutants are not well understood and need to be further investigated. We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories we analyze the transport regimes prevalent during spring (RACEPAC 2014 and NETCARE 2015) and summer (NETCARE 2014) in the observed region. Whereas the eastern part of the Canadian Arctic is affected by air masses with their origin in Asia, in the central and western parts of the Canadian and European Arctic air masses from North America are predominant at the time of the measurement. In general the more northern parts of the Arctic were relatively unaffected by pollution from mid-latitudes since air masses mostly travel within the polar dome, being quite isolated. Associated mixing ratios of CO and CO2 fit into the seasonal cycle observed at NOAA ground stations throughout the Arctic, but show a more mid-latitudinal characteristic at higher altitudes. The transition is remarkably sharp and allows for a chemical definition of the polar dome. At low altitudes, synoptic disturbances transport polluted air masses from mid-latitudes into regions of the polar dome. These air masses contribute to the Arctic pollution background, but also

A numerical investigation of the influence of windscreens on measurement of sound intensity

DEFF Research Database (Denmark)

Juhl, Peter Møller; Jacobsen, Finn

2006-01-01

at low frequencies in strongly reactive sound fields. The theoretical part of this study was based on the assumption of a windscreen of infinite extent. In this paper windscreens of realistic size and shape are dealt with by means of a coupled boundary element model for the windscreen and the surrounding...... air. The error of the estimated intensity caused by the windscreen is calculated under a number of sound field conditions of varying reactivity. It is shown that the resulting error can be much larger than the intensity itself in a very reactive sound field. It is also shown that the shape and size...

Problems in nonlinear acoustics: Scattering of sound by sound, parametric receiving arrays, nonlinear effects in asymmetric sound beams and pulsed finite amplitude sound beams

Science.gov (United States)

Hamilton, Mark F.

1989-08-01

Four projects are discussed in this annual summary report, all of which involve basic research in nonlinear acoustics: Scattering of Sound by Sound, a theoretical study of two nonconlinear Gaussian beams which interact to produce sum and difference frequency sound; Parametric Receiving Arrays, a theoretical study of parametric reception in a reverberant environment; Nonlinear Effects in Asymmetric Sound Beams, a numerical study of two dimensional finite amplitude sound fields; and Pulsed Finite Amplitude Sound Beams, a numerical time domain solution of the KZK equation.

Inter-annual variability of air mass and acidified pollutants transboundary exchange in the north-eastern part of the EANET region

Science.gov (United States)

Gromov, Sergey A.; Trifonova-Yakovleva, Alisa; Gromov, Sergey S.

2016-04-01

Anthropogenic emissions, be it exhaust gases or aerosols, stem from multitude of sources and may survive long-range transport within the air masses they were emitted into. So they follow regional and global transport pathways varying under different climatological regimes. Transboundary transfer of pollutants occurs this way and has a significant impact on the ecological situation of the territories neighbouring those of emission sources, as found in a few earlier studies examining the environmental monitoring data [1]. In this study, we employ a relatively facile though robust technique for estimating the transboundary air and concomitant pollutant fluxes using actual or climatological meteorological and air pollution monitoring data. Practically, we assume pollutant transfer being proportional to the horizontal transport of air enclosed in the lower troposphere and to the concentration of the pollutant of interest. The horizontal transport, in turn, is estimated using the mean layer wind direction and strength, or their descriptive statistics at the individual transects of the boundary of interest. The domain of our interest is the segment of Russian continental border in East Asia spanning from 88° E (southern Middle Siberia) to 135° E (Far East at Pacific shore). The data on atmospheric pollutants concentration are available from the Russian monitoring sites of the region-wide Acid Deposition Monitoring Network in East Asia (EANET, http://www.eanet.asia/) Mondy (Baikal area) and Primorskaya (near Vladivostok). The data comprises multi-year continuous measurement of gas-phase and particulate species abundances in air with at least biweekly sampling rate starting from 2000. In the first phase of our study, we used climatological dataset on winds derived from the aerological soundings at Russian stations along the continental border for the 10-year period (1961-1970) by the Research Institute of Hydrometeorological Information - World Data Centre (RIHMI-WDC) [3

Analysis of the HVAC system's sound quality using the design of experiments

International Nuclear Information System (INIS)

Park, Sang Gil; Sim, Hyun Jin; Yoon, Ji Hyun; Jeong, Jae Eun; Choi, Byoung Jae; Oh, Jae Eung

2009-01-01

Human hearing is very sensitive to sound, so a subjective index of sound quality is required. Each situation of sound evaluation is composed of Sound Quality (SQ) metrics. When substituting the level of one frequency band, we could not see the tendency of substitution at the whole frequency band during SQ evaluation. In this study, the Design of Experiments (DOE) is used to analyze noise from an automotive Heating, Ventilating, and Air Conditioning (HVAC) system. The frequency domain is divided into 12 equal parts, and each level of the domain is given an increase or decrease due to the change in frequency band based on the 'loud' and 'sharp' sound of the SQ analyzed. By using DOE, the number of tests is effectively reduced by the number of experiments, and the main result is a solution at each band. SQ in terms of the 'loud' and 'sharp' sound at each band, the change in band (increase or decrease in sound pressure) or no change in band will have the most effect on the identifiable characteristics of SQ. This will enable us to select the objective frequency band. Through the results obtained, the physical level changes in arbitrary frequency domain sensitivity can be determined

Potential environmental drivers of a regional blue mussel mass mortality event (winter of 2014, Breton Sound, France)

Science.gov (United States)

Polsenaere, Pierre; Soletchnik, Patrick; Le Moine, Olivier; Gohin, Francis; Robert, Stéphane; Pépin, Jean-François; Stanisière, Jean-Yves; Dumas, Franck; Béchemin, Christian; Goulletquer, Philippe

2017-05-01

In the context of global change, increasing mariculture production has raised particular concerns regarding its environmental impact and sustainability. Molluscs and particularly blue mussel account for a significant part of this total production. Although blue mussels are considered to be pretty resilient to environmental disturbances, we report in this study an unprecedented mussel mortality event that occurred during the winter of 2014 in the Breton Sound. 9000 metric tonnes of mussels were lost and mortality rates up to 100% were recorded at some farming areas. Through a coupling approach, the present work aims to better understand the potential environmental drivers associated with those mortalities. Firstly, we analysed long-term in situ and satellite data from environmental monitoring networks (available since 1998) to characterize the variability of seawater masses of the sound during the winter of 2014. Secondly, we used modelling simulations to study the possible relationship between seawater hydrodynamics and observed spatio-temporal patterns of mussel mortalities. From January to April 2014 at the long-line culture site where mortalities started, seawater temperatures ranged from 8.3 to 13.3 °C (10.2 ± 0.8 °C). Salinity and turbidity values showed successive and short drops (below 16; 29.3 ± 2.3) and numerous peaks (above 70 NTU; 17.4 ± 13.4 NTU) respectively. Winter conditions of 2014 were encountered along the entire French Atlantic coastline and linked to the sixth highest positive North Atlantic Oscillation (NAO +) index recorded since 1865. These particular environmental variations characterized the winter of 2014 but also others whereas no comparable mussel mortality rates were reported. Exact causes of the 2014 mortality event are still unknown but we showed these environmental variations could not alone be responsible. These have likely affected the sensitivity of the blue mussel populations that were already weakened by early spawning

The natural history of sound localization in mammals – a story of neuronal inhibition

Directory of Open Access Journals (Sweden)

Benedikt eGrothe

2014-10-01

Full Text Available Our concepts of sound localization in the vertebrate brain are widely based on the general assumption that both the ability to detect air-borne sounds and the neuronal processing are homologous in archosaurs (present day crocodiles and birds and mammals. Yet studies repeatedly report conflicting results on the neuronal circuits and mechanisms, in particular the role of inhibition, as well as the coding strategies between avian and mammalian model systems.Here we argue that mammalian and avian phylogeny of spatial hearing is characterized by a convergent evolution of hearing air-borne sounds rather than by homology. In particular, the different evolutionary origins of tympanic ears and the different availability of binaural cues in early mammals and archosaurs imposed distinct constraints on the respective binaural processing mechanisms. The role of synaptic inhibition in generating binaural spatial sensitivity in mammals is highlighted, as it reveals a unifying principle of mammalian circuit design for encoding sound position. Together, we combine evolutionary, anatomical and physiological arguments for making a clear distinction between mammalian processing mechanisms and coding strategies and those of archosaurs. We emphasize that a consideration of the convergent nature of neuronal mechanisms will significantly increase the explanatory power of studies of spatial processing in both mammals and birds.

Condensation of atmospheric moisture from tropical maritime air masses as a freshwater resource.

Science.gov (United States)

Gerard, R D; Worzel, J L

1967-09-15

A method is proposed whereby potable water may be obtained by condensing moisture from the atmosphere in suitable seashore or island areas. Deep, cold, offshore seawater is used as a source of cold and is pumped to condensers set up on shore to intercept the flow of highly humid, tropical, maritime air masses. This air, when cooled, condenses moisture, which is conducted away and stored for use as a water supply. Windmill-driven generators would supply low-cost power for the operation. Side benefits are derived by using the nutritious deep water to support aquiculture in nearby lagoons or to enhance the productivity of the outfall area. Additional benefits are derived from the condenser as an air-conditioning device for nearby residents. The islands of the Caribbean are used as an example of a location in the trade-winds belt where nearly optimum conditions for the operation of this system can be found.

The propagation of sound in narrow street canyons

Science.gov (United States)

Iu, K. K.; Li, K. M.

2002-08-01

This paper addresses an important problem of predicting sound propagation in narrow street canyons with width less than 10 m, which are commonly found in a built-up urban district. Major noise sources are, for example, air conditioners installed on building facades and powered mechanical equipment for repair and construction work. Interference effects due to multiple reflections from building facades and ground surfaces are important contributions in these complex environments. Although the studies of sound transmission in urban areas can be traced back to as early as the 1960s, the resulting mathematical and numerical models are still unable to predict sound fields accurately in city streets. This is understandable because sound propagation in city streets involves many intriguing phenomena such as reflections and scattering at the building facades, diffusion effects due to recessions and protrusions of building surfaces, geometric spreading, and atmospheric absorption. This paper describes the development of a numerical model for the prediction of sound fields in city streets. To simplify the problem, a typical city street is represented by two parallel reflecting walls and a flat impedance ground. The numerical model is based on a simple ray theory that takes account of multiple reflections from the building facades. The sound fields due to the point source and its images are summed coherently such that mutual interference effects between contributing rays can be included in the analysis. Indoor experiments are conducted in an anechoic chamber. Experimental data are compared with theoretical predictions to establish the validity and usefulness of this simple model. Outdoor experimental measurements have also been conducted to further validate the model. copyright 2002 Acoustical Society of America.

Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

Science.gov (United States)

Shirley, John A.; Winter, Michael

1993-01-01

An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

In-air and underwater hearing of the cormorant

DEFF Research Database (Denmark)

Larsen, Ole Næsbye; Wahlberg, Magnus; Christensen-Dalsgaard, Jakob

Numerous studies have mapped the hearing abilities of birds in air but currently there is little or no data on how diving birds hear or react to sound under water. Therefore, it is unknown whether the ears and auditory system of diving birds are adapted to underwater hearing. In the present study...... 10 cm under water in a large water filled-tank while being artificially ventilated. ABR-responses to calibrated tone bursts produced by a woofer and an underwater speaker, respectively, were measured at different intensities and frequencies to obtain hearing threshold values in air and under water......Hz) under water. Generally, the cormorant ear was not very sensitive to sound, neither in air nor under water. The hearing abilities in water, however, were better than what would have been expected for a purely in-air adapted ear. (Supported by the Carlsberg Foundation 2009_01_0292 and the Danish Council...

Engineering Model of High Pressure Moist Air

OpenAIRE

Hyhlík Tomáš

2017-01-01

The article deals with the moist air equation of state. There are equations of state discussed in the article, i.e. the model of an ideal mixture of ideal gases, the model of an ideal mixture of real gases and the model based on the virial equation of state. The evaluation of sound speed based on the ideal mixture concept is mentioned. The sound speed calculated by the model of an ideal mixture of ideal gases is compared with the sound speed calculated by using the model based on the concept ...

Imagining Sound

DEFF Research Database (Denmark)

Grimshaw, Mark; Garner, Tom Alexander

2014-01-01

We make the case in this essay that sound that is imagined is both a perception and as much a sound as that perceived through external stimulation. To argue this, we look at the evidence from auditory science, neuroscience, and philosophy, briefly present some new conceptual thinking on sound...... that accounts for this view, and then use this to look at what the future might hold in the context of imagining sound and developing technology....

Cluster Analysis of the Organic Peaks in Bulk Mass Spectra Obtained During the 2002 New England Air Quality Study with an Aerodyne Aerosol Mass Spectrometer

Science.gov (United States)

Marcolli, C.; Canagaratna, M. R.; Worsnop, D. R.; Bahreini, R.; de Gouw, J. A.; Warneke, C.; Goldan, P. D.; Kuster, W. C.; Williams, E. J.; Lerner, B. M.; Roberts, J. M.; Meagher, J. F.; Fehsenfeld, F. C.; Marchewka, M.; Bertman, S. B.; Middlebrook, A. M.

2006-12-01

We applied hierarchical cluster analysis to an Aerodyne aerosol mass spectrometer (AMS) bulk mass spectral dataset collected aboard the NOAA research vessel R. H. Brown during the 2002 New England Air Quality Study off the east coast of the United States. Emphasizing the organic peaks, the cluster analysis yielded a series of categories that are distinguishable with respect to their mass spectra and their occurrence as a function of time. The differences between the categories mainly arise from relative intensity changes rather than from the presence or absence of specific peaks. The most frequent category exhibits a strong signal at m/z 44 and represents oxidized organic matter probably originating from both anthropogenic as well as biogenic sources. On the basis of spectral and trace gas correlations, the second most common category with strong signals at m/z 29, 43, and 44 contains contributions from isoprene oxidation products. The third through the fifth most common categories have peak patterns characteristic of monoterpene oxidation products and were most frequently observed when air masses from monoterpene rich regions were sampled. Taken together, the second through the fifth most common categories represent on average 17% of the total organic mass that stems likely from biogenic sources during the ship's cruise. These numbers have to be viewed as lower limits since the most common category was attributed to anthropogenic sources for this calculation. The cluster analysis was also very effective in identifying a few contaminated mass spectra that were not removed during pre-processing. This study demonstrates that hierarchical clustering is a useful tool to analyze the complex patterns of the organic peaks in bulk aerosol mass spectra from a field study.

Characterization of ion processes in a GC/DMS air quality monitor by integration of the instrument to a mass spectrometer.

Science.gov (United States)

Limero, T F; Nazarov, E G; Menlyadiev, M; Eiceman, G A

2015-02-07

The air quality monitor (AQM), which included a portable gas chromatograph (GC) and a detector was interfaced to a mass spectrometer (MS) by introducing flow from the GC detector to the atmospheric pressure ion source of the MS. This small GC system, with a gas recirculation loop for carrier and detector make-up gases, comprised an inlet to preconcentrate volatile organic compounds (VOCs) in air, a thermal desorber before the GC column, a differential mobility spectrometer (DMS), and another DMS as an atmospheric pressure ionization source for the MS. Return flow to the internally recirculated air system of the AQM's DMS was replenished using purified air. Although ions and unreacted neutral vapors flowed from the detector through Viton® tubing into the source of the MS, ions were not detected in the MS without the auxillary ion source, (63)Ni as in the mobility detector. The GC-DMS-MS instrument provided a 3-D measurement platform (GC, DMS, and MS analysis) to explore the gas composition inside the GC-DMS recirculation loop and provide DMS-MS measurement of the components of a complex VOC mixture with performance significantly enhanced by mass-analysis, either with mass spectral scans or with an extracted ion chromatogram. This combination of a mobility spectrometer and a mass spectrometer was possible as vapors and ions are carried together through the DMS analyzer, thereby preserving the chromatographic separation efficiency. The critical benefit of this instrument concept is that all flows in and through the thoroughly integrated GC-DMS analyzer are kept intact allowing a full measure of the ion and vapor composition in the complete system. Performance has been evaluated using a synthetic air sample and a sample of airborne vapors in a laboratory. Capabilities and performance values are described using results from AQM-MS analysis of purified air, ambient air from a research laboratory in a chemistry building, and a sample of synthetic air of known composition

Method and Apparatus of Measuring Velocity and Sound Attenuation Coefficient in Bulk Materials Based on the Analysis of the Structure of Sound-Insulation Materials on the Basis of Perlite

Science.gov (United States)

Kapranov, B. I.; Mashanov, A. P.

2017-04-01

This paper presents the results of research and describes the apparatus for measuring the acoustic characteristics of bulk materials. Ultrasound, it has passed through a layer of bulk material, is further passes through an air gap. The presence of air gap prevents from measuring tract mechanical contacts, but complicates the measurement technology Studies were conducted on the example of measuring the acoustic characteristics of the widely used perlite-based sound-proofing material.

Origin of polluted air masses in the Alps. An overview and first results for MONARPOP

International Nuclear Information System (INIS)

Kaiser, August

2009-01-01

The contribution of ZAMG to MONAROP consists of special weather forecasts to control the SOCs sampling procedure and of the analysis of the specific transport processes for SOCs, which is still in progress. In this paper, air pollutant transport into the Alps is demonstrated by examples of inorganic pollutants: Measurements of NO x and ozone provide evidence for air pollutant transport by local wind systems (valley and slope winds), especially at low elevated sites of the Alps. In addition, trajectory analyses for the high elevation sites demonstrate the importance of large scale synoptic air pollutant transport. The effects of these transport processes with different spatial and temporal scales are governed by the physical and chemical properties of the particular pollutant. First results for the high alpine MONARPOP stations show that air masses from east Europe influence mostly Sonnblick (Austria), whereas the influence of the Po basin is strongest at Weissfluhjoch (Switzerland). - Effects of meteorological transport processes on air pollution in the Alps are demonstrated by examples of inorganic pollutants and first conclusions for SOCs are drawn.

Overview of aerosol properties associated with air masses sampled by the ATR-42 during the EUCAARI campaign (2008

Directory of Open Access Journals (Sweden)

S. Crumeyrolle

2013-05-01

Full Text Available Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI project, the Météo-France aircraft ATR-42 performed 22 research flights over central Europe and the North Sea during the intensive observation period in May 2008. For the campaign, the ATR-42 was equipped to study the aerosol physical, chemical, hygroscopic and optical properties, as well as cloud microphysics. For the 22 research flights, retroplume analyses along the flight tracks were performed with FLEXPART in order to classify air masses into five sectors of origin, allowing for a qualitative evaluation of emission influence on the respective air parcel. This study shows that the extensive aerosol parameters (aerosol mass and number concentrations show vertical decreasing gradients and in some air masses maximum mass concentrations (mainly organics in an intermediate layer (1–3 km. The observed mass concentrations (in the boundary layer (BL: between 10 and 30 μg m−3; lower free troposphere (LFT: 0.8 and 14 μg m−3 are high especially in comparison with the 2015 European norms for PM2.5 (25 μg m−3 and with previous airborne studies performed over England (Morgan et al., 2009; McMeeking et al., 2012. Particle number size distributions show a larger fraction of particles in the accumulation size range in the LFT compared to BL. The chemical composition of submicron aerosol particles is dominated by organics in the BL, while ammonium sulphate dominates the submicron aerosols in the LFT, especially in the aerosol particles originated from north-eastern Europe (~ 80%, also experiencing nucleation events along the transport. As a consequence, first the particle CCN acting ability, shown by the CCN/CN ratio, and second the average values of the scattering cross sections of optically active particles (i.e. scattering coefficient divided by the optical active particle concentration are increased in the LFT compared to BL.

Modelling and optimization of the sound absorption of wood-wool cement boards

NARCIS (Netherlands)

Botterman, B.; Doudart de la Grée, G.C.H.; Hornikx, M.C.J.; Yu, Q.; Brouwers, H.J.H.

2018-01-01

The present article aims to characterize and improve the sound absorption of wood-wool cement boards (WWCB) with varying strand widths, densities, thicknesses and applied with varying air cavity thicknesses by using impedance models. Different rigid-frame impedance models were analysed to predict

Universal formula for the holographic speed of sound

Science.gov (United States)

Anabalón, Andrés; Andrade, Tomás; Astefanesei, Dumitru; Mann, Robert

2018-06-01

We consider planar hairy black holes in five dimensions with a real scalar field in the Breitenlohner-Freedman window and derive a universal formula for the holographic speed of sound for any mixed boundary conditions of the scalar field. As an example, we numerically construct the most general class of planar black holes coupled to a single scalar field in the consistent truncation of type IIB supergravity that preserves the SO (3) × SO (3) R-symmetry group of the gauge theory. For this particular family of solutions, we find that the speed of sound exceeds the conformal value. From a phenomenological point of view, the fact that the conformal bound can be violated by choosing the right mixed boundary conditions is relevant for the existence of neutron stars with a certain mass-size relationship for which a large value of the speed of sound codifies a stiff equation of state. In the way, we also shed light on a puzzle regarding the appearance of the scalar charges in the first law. Finally, we generalize the formula of the speed of sound to arbitrary dimensional scalar-metric theories whose parameters lie within the Breitenlohner-Freedman window.

Modelling absorption in porous asphalt concrete for oblique incident sound waves

NARCIS (Netherlands)

Bezemer-Krijnen, Marieke; Wijnant, Ysbrand H.; de Boer, Andries; Sas, P; Moens, D.; Denayer, H.

2014-01-01

A numerical model to predict the sound absorption of porous asphalt has been developed. The approach is a combination between a microstructural approach and a finite element approach. The model used to describe the viscothermal properties of the air inside the pores of the asphalt is the low reduced

Sound radiation contrast in MR phase images. Method for the representation of elasticity, sound damping, and sound impedance changes

International Nuclear Information System (INIS)

Radicke, Marcus

2009-01-01

The method presented in this thesis combines ultrasound techniques with the magnetic-resonance tomography (MRT). An ultrasonic wave generates in absorbing media a static force in sound-propagation direction. The force leads at sound intensities of some W/cm 2 and a sound frequency in the lower MHz range to a tissue shift in the micrometer range. This tissue shift depends on the sound power, the sound frequency, the sound absorption, and the elastic properties of the tissue. A MRT sequence of the Siemens Healthcare AG was modified so that it measures (indirectly) the tissue shift, codes as grey values, and presents as 2D picture. By means of the grey values the sound-beam slope in the tissue can be visualized, and so additionally sound obstacles (changes of the sound impedance) can be detected. By the MRT images token up spatial changes of the tissue parameters sound absorption and elasticity can be detected. In this thesis measurements are presented, which show the feasibility and future chances of this method especially for the mammary-cancer diagnostics. [de

Influence of the outlet air temperature on the thermohydraulic behaviour of air coolers

Directory of Open Access Journals (Sweden)

Đorđević Emila M.

2003-01-01

Full Text Available The determination of the optimal process conditions for the operation of air coolers demands a detailed analysis of their thermohydraulic behaviour on the one hand, and the estimation of the operating costs, on the other. One of the main parameters of the thermohydraulic behaviour of this type of equipment, is the outlet air temperature. The influence of the outlet air temperature on the performance of air coolers (heat transfer coefficient overall heat transfer coefficient, required surface area for heat transfer air-side pressure drop, fan power consumption and sound pressure level was investigated in this study. All the computations, using AirCooler software [1], were applied to cooling of the process fluid and the condensation of a multicomponent vapour mixture on two industrial devices of known geometries.

Heat and mass transfer in air-fed pressurised suits

International Nuclear Information System (INIS)

Tesch, K.; Collins, M.W.; Karayiannis, T.G.; Atherton, M.A.; Edwards, P.

2009-01-01

Air-fed pressurised suits are used to protect workers against contamination and hazardous environments. The specific application here is the necessity for regular clean-up maintenance within the torus chamber of fusion reactors. The current design of suiting has been developed empirically. It is, therefore, very desirable to formulate a thermo-fluids model, which will be able to define optimum designs and operating parameters. Two factors indicate that the modelling should be as comprehensive as possible. Firstly, the overall thermo-fluids problem is three-dimensional and includes mass as well as heat transfer. The fluid field is complex, bounded on one side by the human body and on the other by what may be distensible, porous and multi-layer clothing. In this paper, we report firstly the modelling necessary for the additional mass and heat transport processes. This involves the use of Fick's and Fourier's laws and conjugate heat transfer. The results of an initial validation study are presented. Temperatures at the outlet of the suits were obtained experimentally and compared with those predicted by the overall CFD model. Realistic three-dimensional geometries were used for the suit and human body. Calculations were for turbulent flow with single- and two-component (species) models

Effect of Poisson's loss factor of rubbery material on underwater sound absorption of anechoic coatings

Science.gov (United States)

Zhong, Jie; Zhao, Honggang; Yang, Haibin; Yin, Jianfei; Wen, Jihong

2018-06-01

Rubbery coatings embedded with air cavities are commonly used on underwater structures to reduce reflection of incoming sound waves. In this paper, the relationships between Poisson's and modulus loss factors of rubbery materials are theoretically derived, the different effects of the tiny Poisson's loss factor on characterizing the loss factors of shear and longitudinal moduli are revealed. Given complex Young's modulus and dynamic Poisson's ratio, it is found that the shear loss factor has almost invisible variation with the Poisson's loss factor and is very close to the loss factor of Young's modulus, while the longitudinal loss factor almost linearly decreases with the increase of Poisson's loss factor. Then, a finite element (FE) model is used to investigate the effect of the tiny Poisson's loss factor, which is generally neglected in some FE models, on the underwater sound absorption of rubbery coatings. Results show that the tiny Poisson's loss factor has a significant effect on the sound absorption of homogeneous coatings within the concerned frequency range, while it has both frequency- and structure-dependent influence on the sound absorption of inhomogeneous coatings with embedded air cavities. Given the material parameters and cavity dimensions, more obvious effect can be observed for the rubbery coating with a larger lattice constant and/or a thicker cover layer.

Spherical collapse in quintessence models with zero speed of sound

International Nuclear Information System (INIS)

Creminelli, Paolo; D'Amico, Guido; Noreña, Jorge; Senatore, Leonardo; Vernizzi, Filippo

2010-01-01

We study the spherical collapse model in the presence of quintessence with negligible speed of sound. This case is particularly motivated for w Q /Ω m . This gives a distinctive modification of the total mass function at low redshift

Trophic mass-balance model of Alaska's Prince William Sound ecosystem, for the post-spill period 1994-1996

International Nuclear Information System (INIS)

Okey, T.A.; Pauly, D.

1998-01-01

The Ecopath modelling approach for the Prince William Sound (PWS) ecosystem was described. The area is the site of the 1989 Exxon Valdez oil spill (EVOS), the largest spill in U.S. history. 36,000 tonnes of crude oil spread throughout the central and southwestern PWS into the Gulf of Alaska and along the Kenai and Alaska Peninsula. The initial effects of the oil spill were catastrophic. The Ecopath modelling approach discussed in this report is aimed at providing a cohesive picture of the PWS ecosystem by constructing a mass-balanced model of food-web interactions and trophic flows using information collected since the EVOS. The model includes all biotic components of the ecosystem and provides a quantitative description of food-web interactions and relationships, as well as energy flows among components. The model can provide an understanding of how ecosystems respond to disturbances, such as oil spills. 216 refs., 74 tabs., 13 figs., 8 appendices

Toward a better understanding of the impact of mass transit air pollutants on human health.

Science.gov (United States)

Kim, Ki-Hyun; Kumar, Pawan; Szulejko, Jan E; Adelodun, Adedeji A; Junaid, Muhammad Faisal; Uchimiya, Minori; Chambers, Scott

2017-05-01

Globally, modern mass transport systems whether by road, rail, water, or air generate airborne pollutants in both developing and developed nations. Air pollution is the primary human health concern originating from modern transportation, particularly in densely-populated urban areas. This review will specifically focus on the origin and the health impacts of carbonaceous traffic-related air pollutants (TRAP), including particulate matter (PM), volatile organic compounds (VOCs), and elemental carbon (EC). We conclude that the greatest current challenge regarding urban TRAP is understanding and evaluating the human health impacts well enough to set appropriate pollution control measures. Furthermore, we provide a detailed discussion regarding the effects of TRAP on local environments and pedestrian health in low and high traffic-density environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Finite element analysis of an inflatable torus considering air mass structural element

Science.gov (United States)

Gajbhiye, S. C.; Upadhyay, S. H.; Harsha, S. P.

2014-01-01

Inflatable structures, also known as gossamer structures, are at high boom in the current space technology due to their low mass and compact size comparing to the traditional spacecraft designing. Internal pressure becomes the major source of strength and rigidity, essentially stiffen the structure. However, inflatable space based membrane structure are at high risk to the vibration disturbance due to their low structural stiffness and material damping. Hence, the vibration modes of the structure should be known to a high degree of accuracy in order to provide better control authority. In the past, most of the studies conducted on the vibration analysis of gossamer structures used inaccurate or approximate theories in modeling the internal pressure. The toroidal shaped structure is one of the important key element in space application, helps to support the reflector in space application. This paper discusses the finite-element analysis of an inflated torus. The eigen-frequencies are obtained via three-dimensional small-strain elasticity theory, based on extremum energy principle. The two finite-element model (model-1 and model-2) have cases have been generated using a commercial finite-element package. The structure model-1 with shell element and model-2 with the combination of the mass of enclosed fluid (air) added to the shell elements have been taken for the study. The model-1 is computed with present analytical approach to understand the convergence rate and the accuracy. The convergence study is made available for the symmetric modes and anti-symmetric modes about the centroidal-axis plane, meeting the eigen-frequencies of an inflatable torus with the circular cross section. The structural model-2 is introduced with air mass element and analyzed its eigen-frequency with different aspect ratio and mode shape response using in-plane and out-plane loading condition are studied.

Source attribution of Bornean air masses by back trajectory analysis during the OP3 project

Directory of Open Access Journals (Sweden)

N. H. Robinson

2011-09-01

Full Text Available Atmospheric composition affects the radiative balance of the Earth through the creation of greenhouse gases and the formation of aerosols. The latter interact with incoming solar radiation, both directly and indirectly through their effects on cloud formation and lifetime. The tropics have a major influence on incoming sunlight however the tropical atmosphere is poorly characterised, especially outside Amazonia. The origins of air masses influencing a measurement site in a protected rainforest in Borneo, South East Asia, were assessed and the likely sources of a range of trace gases and particles were determined. This was conducted by interpreting in situ measurements made at the site in the context of ECMWF backwards air mass trajectories. Two different but complementary methods were employed to interpret the data: comparison of periods classified by cluster analysis of trajectories, and inspection of the dependence of mean measured values on geographical history of trajectories. Sources of aerosol particles, carbon monoxide and halocarbons were assessed. The likely source influences include: terrestrial organic biogenic emissions; long range transport of anthropogenic emissions; biomass burning; sulphurous emissions from marine phytoplankton, with a possible contribution from volcanoes; marine production of inorganic mineral aerosol; and marine production of halocarbons. Aerosol sub- and super-saturated water affinity was found to be dependent on source (and therefore composition, with more hygroscopic aerosol and higher numbers of cloud condensation nuclei measured in air masses of marine origin. The prevailing sector during the majority of measurements was south-easterly, which is from the direction of the coast closest to the site, with a significant influence inland from the south-west. This analysis shows that marine and terrestrial air masses have different dominant chemical sources. Comparison with the AMAZE-08 project in the Amazon

Radon derived air mass fetch regions during the ACE-Asia campaign

International Nuclear Information System (INIS)

Chambers, S.; Zahorowski, W.; Werczynski, S.; Wang, T.; Poon, S.; Kim, J.; Oh, S.-N.; Knag, H.; Uematsu, M.; Matsumoto, K.

2003-01-01

Seasonal variations in fetch regions for air masses exhibiting the greatest and least terrestrial influence at three sites in East Asia are discussed. Results are based on the first year of hourly atmospheric radon concentration observations made as part of the Asian Aerosol Characterisation Experiment (ACE-Asia). Fetch regions for Asian continental outflow to the Pacific Basin within the boundary layer are shown to be distinct from corresponding tropospheric outflow events. Analysis of the hourly radon time series in conjunction with back trajectory analysis indicates the presence of a large localised radon source in south eastern China

The influence of the thermo-phono-insulating glazing structure configuration of some PVC profile windows on the airborne sound insulation – case study

Directory of Open Access Journals (Sweden)

Marta Cristina ZAHARIA

2012-12-01

Full Text Available After conducting laboratory acoustic measurements of airborne sound insulation for several windows with the same type of PVC profiles, equipped with different types of phono- and thermal - insulating glazings, the influence of the window’s glazed part (glass structure configuration on airborne sound insulation was analyzed. The configuration of the structure’s glazed part requires its composition of glass sheets with different thicknesses or intermediate layers of air with different thicknesses. This configuration has an important influence on the acoustic response of windows, namely on the index of air noise sound insulation, Rw, and on the behavior of the entire measurement frequency range.

Optimization of orthotropic distributed-mode loudspeaker using attached masses and multi-exciters.

Science.gov (United States)

Lu, Guochao; Shen, Yong; Liu, Ziyun

2012-02-01

Based on the orthotropic model of the plate, the method to optimize the sound response of the distributed-mode loudspeaker (DML) using the attached masses and the multi-exciters has been investigated. The attached masses method will rebuild the modes distribution of the plate, based on which multi-exciter method will smooth the sound response. The results indicate that the method can be used to optimize the sound response of the DML. © 2012 Acoustical Society of America

Development of Prediction Tool for Sound Absorption and Sound Insulation for Sound Proof Properties

OpenAIRE

Yoshio Kurosawa; Takao Yamaguchi

2015-01-01

High frequency automotive interior noise above 500 Hz considerably affects automotive passenger comfort. To reduce this noise, sound insulation material is often laminated on body panels or interior trim panels. For a more effective noise reduction, the sound reduction properties of this laminated structure need to be estimated. We have developed a new calculate tool that can roughly calculate the sound absorption and insulation properties of laminate structure and handy ...

Parameterizing Sound: Design Considerations for an Environmental Sound Database

Science.gov (United States)

2015-04-01

associated with, or produced by, a physical event or human activity and 2) sound sources that are common in the environment. Reproductions or sound...Rogers S. Confrontation naming of environmental sounds. Journal of Clinical and Experimental Neuropsychology . 2000;22(6):830–864. 14 VanDerveer NJ

Cluster Analysis of the Organic Peaks in Bulk Mass Spectra Obtained During the 2002 New England Air Quality Study with an Aerodyne Aerosol Mass Spectrometer

Directory of Open Access Journals (Sweden)

C. Marcolli

2006-01-01

Full Text Available We applied hierarchical cluster analysis to an Aerodyne aerosol mass spectrometer (AMS bulk mass spectral dataset collected aboard the NOAA research vessel R. H. Brown during the 2002 New England Air Quality Study off the east coast of the United States. Emphasizing the organic peaks, the cluster analysis yielded a series of categories that are distinguishable with respect to their mass spectra and their occurrence as a function of time. The differences between the categories mainly arise from relative intensity changes rather than from the presence or absence of specific peaks. The most frequent category exhibits a strong signal at m/z 44 and represents oxidized organic matter probably originating from both anthropogenic as well as biogenic sources. On the basis of spectral and trace gas correlations, the second most common category with strong signals at m/z 29, 43, and 44 contains contributions from isoprene oxidation products. The third through the fifth most common categories have peak patterns characteristic of monoterpene oxidation products and were most frequently observed when air masses from monoterpene rich regions were sampled. Taken together, the second through the fifth most common categories represent on average 17% of the total organic mass that stems likely from biogenic sources during the ship's cruise. These numbers have to be viewed as lower limits since the most common category was attributed to anthropogenic sources for this calculation. The cluster analysis was also very effective in identifying a few contaminated mass spectra that were not removed during pre-processing. This study demonstrates that hierarchical clustering is a useful tool to analyze the complex patterns of the organic peaks in bulk aerosol mass spectra from a field study.

Seasonal and air mass trajectory effects on dissolved organic matter of bulk deposition at a coastal town in south-western Europe.

Science.gov (United States)

Santos, Patrícia S M; Santos, Eduarda B H; Duarte, Armando C

2013-01-01

Rainwater contains a complex mixture of organic compounds which may influence climate, terrestrial and maritime ecosystems and thus human health. In this work, the characteristics of DOM of bulk deposition at a coastal town on the southwest of Europe were assessed by UV-visible and three-dimensional excitation-emission matrix fluorescence spectroscopies and by dissolved organic carbon (DOC) content. The seasonal and air mass trajectory effects on dissolved organic matter (DOM) of bulk deposition were evaluated. The absorbance at 250 nm (UV(250 nm)) and integrated fluorescence showed to be positively correlated with each other, and they were also positively correlated to the DOC in bulk deposition, which suggest that a constant fraction of DOM is likely to fluoresce. There was more chromophoric dissolved organic matter (CDOM) present in summer and autumn seasons than in winter and spring. Bulk deposition associated with terrestrial air masses contained a higher CDOM content than bulk deposition related to marine air masses, thus highlighting the contribution of terrestrial/anthropogenic sources.

Making fictions sound real - On film sound, perceptual realism and genre

Directory of Open Access Journals (Sweden)

Birger Langkjær

2010-05-01

Full Text Available This article examines the role that sound plays in making fictions perceptually real to film audiences, whether these fictions are realist or non-realist in content and narrative form. I will argue that some aspects of film sound practices and the kind of experiences they trigger are related to basic rules of human perception, whereas others are more properly explained in relation to how aesthetic devices, including sound, are used to characterise the fiction and thereby make it perceptually real to its audience. Finally, I will argue that not all genres can be defined by a simple taxonomy of sounds. Apart from an account of the kinds of sounds that typically appear in a specific genre, a genre analysis of sound may also benefit from a functionalist approach that focuses on how sounds can make both realist and non-realist aspects of genres sound real to audiences.

Making fictions sound real - On film sound, perceptual realism and genre

Directory of Open Access Journals (Sweden)

Birger Langkjær

2009-09-01

Full Text Available This article examines the role that sound plays in making fictions perceptually real to film audiences, whether these fictions are realist or non-realist in content and narrative form. I will argue that some aspects of film sound practices and the kind of experiences they trigger are related to basic rules of human perception, whereas others are more properly explained in relation to how aesthetic devices, including sound, are used to characterise the fiction and thereby make it perceptually real to its audience. Finally, I will argue that not all genres can be defined by a simple taxonomy of sounds. Apart from an account of the kinds of sounds that typically appear in a specific genre, a genre analysis of sound may also benefit from a functionalist approach that focuses on how sounds can make both realist and non-realist aspects of genres sound real to audiences.

Energy efficiency and sound protection. In conflict; Energieeffizienz und Schallschutz. Im Konflikt

Energy Technology Data Exchange (ETDEWEB)

Sonnenschein, Udo

2013-06-06

The trend of development of lightweight bricks will go towards a minimization of thermal conductivity and bulk densities. This results to decision conflicts between thermal insulation and sound protection. Bivalve masonries can be used to combine sound protection and thermal insulation still. Bivalve masonries combine the advantages of surface-related mass (double mass) with thermal insulation. Already with a simple construction consisting of brickwork (thermal conductivity: 0.08 W / (m K)) and insulating material (thermal conductivity: 0.035 W / (m K)) heat transfer coefficients of about 0.21 W / (m{sup 2} K) can be achieved. These constructions are harmless in terms of the moisture behavior. The choice of material and the thickness is variable. Different requirements can be met.

A study on calculation method for mechanical impedance of air spring

International Nuclear Information System (INIS)

Changgeng, Shuai; Penghui, Li; Rustighi, Emiliano

2016-01-01

This paper proposes an approximate analytic method of obtaining the mechanical impedance of air spring. The sound pressure distribution in cylindrical air spring is calculated based on the linear air wave theory. The influences of different boundary conditions on the acoustic pressure field distribution in cylindrical air spring are analysed. A 1-order ordinary differential matrix equation for the state vector of revolutionary shells under internal pressure is derived based on the non-moment theory of elastic thin shell. Referring to the transfer matrix method, a kind of expanded homogeneous capacity high precision integration method is introduced to solve the non-homogeneous matrix differential equation. Combined the solved stress field of shell with the calculated sound pressure field in air spring under the displacement harmonic excitation, the approximate analytical expression of the input and transfer mechanical impedance for the air spring can be achieved. The numerical simulation with the Comsol Multiphysics software verifies the correctness of theoretical analysis result. (paper)

Sound Absorbers

Science.gov (United States)

Fuchs, H. V.; Möser, M.

Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

Relationships between summer air masses and mortality in Seoul: Comparison of weather-type classifications

Czech Academy of Sciences Publication Activity Database

Kyselý, Jan; Huth, Radan

2010-01-01

Roč. 35, 9-12 (2010), s. 536-543 ISSN 1474-7065 R&D Projects: GA ČR GC205/07/J044 Grant - others: Korea Research Foundation(KR) KRF-2006-C00005 Institutional research plan: CEZ:AV0Z30420517 Keywords : Classification of weather types * Air masses * Biometeorology * Human mortality * East Asia Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.917, year: 2010

Amplitude and frequency modulation control of sound production in a mechanical model of the avian syrinx

DEFF Research Database (Denmark)

Elemans, Coen; Muller, Mees; Larsen, Ole Næsbye

2009-01-01

membrane and generate a wide variety of ‘syllables' with simple sweeps of the control parameters. We show that the membrane exhibits high frequency, self-sustained oscillations in the audio range (>600 Hz fundamental frequency) using laser Doppler vibrometry, and systematically explore the conditions...... for sound production of the model in its control space. The fundamental frequency of the sound increases with tension in three membranes with different stiffness and mass. The lowerbound fundamental frequency increases with membrane mass. The membrane vibrations are strongly coupled to the resonance...

Mass casualty tracking with air traffic control methodologies.

Science.gov (United States)

Hoskins, Jason D; Graham, Ross F; Robinson, Duane R; Lutz, Clifford C; Folio, Les R

2009-06-01

An intrahospital casualty throughput system modeled after air traffic control (ATC) tracking procedures was tested in mass casualty exercises. ATC uses a simple tactile process involving informational progress strips representing each aircraft, which are held in bays representing each stage of flight to prioritize and manage aircraft. These strips can be reordered within the bays to indicate a change in priority of aircraft sequence. In this study, a similar system was designed for patient tracking. We compared the ATC model and traditional casualty tracking methods of paper and clipboard in 18 four-hour casualty scenarios, each with 5 to 30 mock casualties. The experimental and control groups were alternated to maximize exposure and minimize training effects. Results were analyzed with Mann-Whitney statistical analysis with p value < 0.05 (two-sided). The ATC method had significantly (p = 0.017) fewer errors in critical patient data (eg, name, social security number, diagnosis). Specifically, the ATC method better tracked the mechanism of injury, working diagnosis, and disposition of patients. The ATC method also performed considerably better with patient accountability during mass casualty scenarios. Data strips were comparable with the control method in terms of ease of use. In addition, participants preferred the ATC method to the control (p = 0.003) and preferred using the ATC method (p = 0.003) to traditional methods in the future. The ATC model more effectively tracked patient data with fewer errors when compared with the clipboard method. Application of these principles can enhance trauma management and can have application in civilian and military trauma centers and emergency rooms.

Abnormal sound detection device

International Nuclear Information System (INIS)

Yamada, Izumi; Matsui, Yuji.

1995-01-01

Only components synchronized with rotation of pumps are sampled from detected acoustic sounds, to judge the presence or absence of abnormality based on the magnitude of the synchronized components. A synchronized component sampling means can remove resonance sounds and other acoustic sounds generated at a synchronously with the rotation based on the knowledge that generated acoustic components in a normal state are a sort of resonance sounds and are not precisely synchronized with the number of rotation. On the other hand, abnormal sounds of a rotating body are often caused by compulsory force accompanying the rotation as a generation source, and the abnormal sounds can be detected by extracting only the rotation-synchronized components. Since components of normal acoustic sounds generated at present are discriminated from the detected sounds, reduction of the abnormal sounds due to a signal processing can be avoided and, as a result, abnormal sound detection sensitivity can be improved. Further, since it is adapted to discriminate the occurrence of the abnormal sound from the actually detected sounds, the other frequency components which are forecast but not generated actually are not removed, so that it is further effective for the improvement of detection sensitivity. (N.H.)

Urban Air Pollution in Taiwan before and after the Installation of a Mass Rapid Transit System.

Science.gov (United States)

Ding, Pei-Hsiou; Wang, Gen-Shuh; Chen, Bing-Yu; Wan, Gwo-Hwa

2016-09-01

Urbanization causes air pollution in metropolitan areas, coupled with meteorological factors that affect air quality. Although previous studies focused on the relationships of urbanization, air pollution, and climate change in Western countries, this study evaluated long-term variations of air quality and meteorological factors in Taiwanese metropolitan areas (Taipei area, Taichung City, and Kaohsiung City) and a rural area (Hualien County) between 1993 and 2012. The influence of a mass rapid transit (MRT) system on air quality was also evaluated. Air pollutant concentrations and meteorology data were collected from Taiwan Environmental Protection Administration (TEPA) air monitoring stations and Central Weather Bureau stations in the surveyed areas, respectively. Analyses indicate that levels of air pollution in metropolitan areas were greater than in the rural area. Kaohsiung City had the highest levels of O, SO, and particulate matter 2.5 or 10 µm in diameter (PM and PM). Clear downward trends for CO, NO, PM, PM, and especially SO concentrations were found in the surveyed areas, whereas O showed no decrease. Both O and PM concentrations showed similar bimodal seasonal distributions. Taiwan's air quality has improved significantly since 1993, indicating the effectiveness of promoting air pollution strategies and policies by the TEPA. Air pollution had an obvious improvement in Taipei area after the MRT system began operations in 1996. Because global climate may potentially affect urban air pollution in Taiwan, further study to clarify the mechanisms by which air pollution may affect human health and other biological effects is warranted. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall.

Science.gov (United States)

Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

2014-11-01

Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005-2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination.

Assessment of the uncertainties in air mass and pollutants transboundary exchange over the continental part of the EANET region

Science.gov (United States)

Gromov, Sergey S.; Trifonova-Yakovleva, Alisa; Gromov, Sergey A.

2017-04-01

In this study, we attempt to quantify the uncertainties in air mass exchange in the lower troposphere across two regions of the Russian border in Eastern Siberia and the Russian Far East in 2000-2015. We use meteorological data from long-term air sound data (ASD) on mean layer winds [1] and from the ERA INTERIM re-analysis (EIR) project [2]. Using a transboundary exchange model, we estimate the total and net amounts of air crossing the boundary segments around Irkutsk (IR) and Vladivostok (VL) aerological stations. We compare transport terms derived (i) from the long-term wind statistics based on both ASD and EIR data, and (ii) from integrating 6h meteorological winds from EIR directly over the border segments cells. We find similar wind direction statistics in both meteorological datasets, however EIR favours stronger westerly winds at VL in summer, which results in more often air export from China to Russia in the Far East. There is less agreement on the wind strengths than wind directions between the datasets, with EIR often providing slower wind speeds. The resulting climatic (ASD) and directly (from EIR 6h terms) calculated non-equilibrium (net) transport terms are comparable in orders (tens of million km3/month), however may differ substantially in temporal evolution or/and magnitude. Thus, EIR net transport over the IR segment has similar annual dynamics but is higher by a factor of ˜ 4 (maxima of 3.6 vs. 12 of 106 km3/month in December, respectively). An opposite ratio is derived for the VL segment (average ˜ 6 vs. 13 of 106 km3/month), with a distinct seasonality in the ASD but not in the EIR data. We attribute this discrepancy to the variations in wind direction with altitude, which cannot be resolved in the model fed with the ASD data. Calculated transport in the boundary layer (BL, provided by the EIR) supports this inference. Thus, the BL net transport temporal dynamics differ substantially from that within the 3 km layer, owing to the BL diurnal

New air Cherenkov light detectors to study mass composition of cosmic rays with energies above knee region

Energy Technology Data Exchange (ETDEWEB)

Tsunesada, Yoshiki, E-mail: tsunesada@cr.phys.titech.ac.jp [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8550 Japan (Japan); Katsuya, Ryoichi, E-mail: katsuya@cr.phys.titech.ac.jp [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8550 Japan (Japan); Mitsumori, Yu; Nakayama, Keisuke; Kakimoto, Fumio; Tokuno, Hisao [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8550 Japan (Japan); Tajima, Norio [RIKEN, Wako, Saitama 351-0198 (Japan); Miranda, Pedro; Salinas, Juan; Tavera, Wilfredo [Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, La Paz (Bolivia, Plurinational State of)

2014-11-01

We have installed a hybrid detection system for air showers generated by cosmic rays with energies greater than 3×10{sup 15}eV at Mount Chacaltaya (5200 m above the sea level), in order to study the mass composition of cosmic rays above the knee region. This detection system comprises an air shower array with 49 scintillation counters in an area of 500 m×650 m, and seven new Cherenkov light detectors installed in a radial direction from the center of the air shower array with a separation of 50 m. It is known that the longitudinal development of a particle cascade in the atmosphere strongly depends on the type of the primary nucleus, and an air shower initiated by a heavier nucleus develops faster than that by a lighter primary of the same energy, because of the differences in the interaction cross-section and the energy per nucleon. This can be measured by detecting the Cherenkov radiation emitted from charged particles in air showers at higher altitudes. In this paper we describe the design and performance of our new non-imaging Cherenkov light detectors at Mount Chacaltaya that are operated in conjunction with the air shower array. The arrival directions and energies of air showers are determined by the shower array, and information about the primary masses is obtained from the Cherenkov light data including the time profiles and lateral distributions. The detector consists of photomultiplier tube (PMT), high-speed ADCs, other control modules, and data storage device. The Cherenkov light signals from an air shower are typically 10–100 ns long, and the waveforms are digitized with a sampling frequency of 1 GHz and recorded in situ without long-distance analog signal transfers. All the Cherenkov light detectors record their time-series data by receiving a triggering signal transmitted from the trigger module of the air shower array, which is fired by a coincidence of shower signals in four neighboring scintillation counters. The optical characteristics of the

Slow-wave metamaterial open panels for efficient reduction of low-frequency sound transmission

Science.gov (United States)

Yang, Jieun; Lee, Joong Seok; Lee, Hyeong Rae; Kang, Yeon June; Kim, Yoon Young

2018-02-01

Sound transmission reduction is typically governed by the mass law, requiring thicker panels to handle lower frequencies. When open holes must be inserted in panels for heat transfer, ventilation, or other purposes, the efficient reduction of sound transmission through holey panels becomes difficult, especially in the low-frequency ranges. Here, we propose slow-wave metamaterial open panels that can dramatically lower the working frequencies of sound transmission loss. Global resonances originating from slow waves realized by multiply inserted, elaborately designed subwavelength rigid partitions between two thin holey plates contribute to sound transmission reductions at lower frequencies. Owing to the dispersive characteristics of the present metamaterial panels, local resonances that trap sound in the partitions also occur at higher frequencies, exhibiting negative effective bulk moduli and zero effective velocities. As a result, low-frequency broadened sound transmission reduction is realized efficiently in the present metamaterial panels. The theoretical model of the proposed metamaterial open panels is derived using an effective medium approach and verified by numerical and experimental investigations.

An anthropometric model to estimate neonatal fat mass using air displacement plethysmography

Directory of Open Access Journals (Sweden)

Deierlein Andrea L

2012-03-01

Full Text Available Abstract Background Current validated neonatal body composition methods are limited/impractical for use outside of a clinical setting because they are labor intensive, time consuming, and require expensive equipment. The purpose of this study was to develop an anthropometric model to estimate neonatal fat mass (kg using an air displacement plethysmography (PEA POD® Infant Body Composition System as the criterion. Methods A total of 128 healthy term infants, 60 females and 68 males, from a multiethnic cohort were included in the analyses. Gender, race/ethnicity, gestational age, age (in days, anthropometric measurements of weight, length, abdominal circumference, skin-fold thicknesses (triceps, biceps, sub scapular, and thigh, and body composition by PEA POD® were collected within 1-3 days of birth. Backward stepwise linear regression was used to determine the model that best predicted neonatal fat mass. Results The statistical model that best predicted neonatal fat mass (kg was: -0.012 -0.064*gender + 0.024*day of measurement post-delivery -0.150*weight (kg + 0.055*weight (kg2 + 0.046*ethnicity + 0.020*sum of three skin-fold thicknesses (triceps, sub scapular, and thigh; R2 = 0.81, MSE = 0.08 kg. Conclusions Our anthropometric model explained 81% of the variance in neonatal fat mass. Future studies with a greater variety of neonatal anthropometric measurements may provide equations that explain more of the variance.

Sound Search Engine Concept

DEFF Research Database (Denmark)

2006-01-01

Sound search is provided by the major search engines, however, indexing is text based, not sound based. We will establish a dedicated sound search services with based on sound feature indexing. The current demo shows the concept of the sound search engine. The first engine will be realased June...

Measurement of the mass energy-absorption coefficient of air for x-rays in the range from 3 to 60 keV.

Science.gov (United States)

Buhr, H; Büermann, L; Gerlach, M; Krumrey, M; Rabus, H

2012-12-21

For the first time the absolute photon mass energy-absorption coefficient of air in the energy range of 10 to 60 keV has been measured with relative standard uncertainties below 1%, considerably smaller than those of up to 2% assumed for calculated data. For monochromatized synchrotron radiation from the electron storage ring BESSY II both the radiant power and the fraction of power deposited in dry air were measured using a cryogenic electrical substitution radiometer and a free air ionization chamber, respectively. The measured absorption coefficients were compared with state-of-the art calculations and showed an average deviation of 2% from calculations by Seltzer. However, they agree within 1% with data calculated earlier by Hubbell. In the course of this work, an improvement of the data analysis of a previous experimental determination of the mass energy-absorption coefficient of air in the range of 3 to 10 keV was found to be possible and corrected values of this preceding study are given.

The sound manifesto

Science.gov (United States)

O'Donnell, Michael J.; Bisnovatyi, Ilia

2000-11-01

Computing practice today depends on visual output to drive almost all user interaction. Other senses, such as audition, may be totally neglected, or used tangentially, or used in highly restricted specialized ways. We have excellent audio rendering through D-A conversion, but we lack rich general facilities for modeling and manipulating sound comparable in quality and flexibility to graphics. We need coordinated research in several disciplines to improve the use of sound as an interactive information channel. Incremental and separate improvements in synthesis, analysis, speech processing, audiology, acoustics, music, etc. will not alone produce the radical progress that we seek in sonic practice. We also need to create a new central topic of study in digital audio research. The new topic will assimilate the contributions of different disciplines on a common foundation. The key central concept that we lack is sound as a general-purpose information channel. We must investigate the structure of this information channel, which is driven by the cooperative development of auditory perception and physical sound production. Particular audible encodings, such as speech and music, illuminate sonic information by example, but they are no more sufficient for a characterization than typography is sufficient for characterization of visual information. To develop this new conceptual topic of sonic information structure, we need to integrate insights from a number of different disciplines that deal with sound. In particular, we need to coordinate central and foundational studies of the representational models of sound with specific applications that illuminate the good and bad qualities of these models. Each natural or artificial process that generates informative sound, and each perceptual mechanism that derives information from sound, will teach us something about the right structure to attribute to the sound itself. The new Sound topic will combine the work of computer

SOUND TRANSMISSION LOSS OF A DOUBLE-LEAF SOLID-MICROPERFORATED PARTITION UNDER NORMAL INCIDENCE OF ACOUSTIC LOADING

Directory of Open Access Journals (Sweden)

Ahmad Yusuf Ismail

2011-12-01

Full Text Available 0 0 1 332 1894 International Islamic University 15 4 2222 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman";} The micro-perforated panel (MPP is recently well-known as an alternative ‘green‘ sound absorber replacing the conventional porous materials. Constructed from a solid panel which provides a non-abrassive structure and also an optically attractive surface, there gives a feasibility to implement such a panel inside a vehicle cabin. This paper is the preliminary study to investigate the sound transmission loss (TL of a solid panel coupled with a micro-perforated panel to form a doube-leaf partition which is already known as a lightweigth stucture for noise insulation in vehicles and buildings. The mathematical model for the TL subjected to normal incidence of acoustic excitation is derived. The results show that its performance substantially improves at the troublesome frequency of mass-air-mass resonance which occurs in the conventional double-leaf solid partition. This is important particularly for the noise source predominant at low frequencies. This can also be controlled by tuning the hole size and number as well as the air gap between the panels.  ABSTRAK: Panel bertebuk mikro (micro-perforated panel (MPP kebelakangan ini dikenali sebagai alternatif penyerap bunyi yang mesra alam menggantikan bahan berliang lazim. Dibina daripada satu panel padu yang memberikan satu struktur tak lelas dan juga satu permukaan yang menarik, ia memberikan kemungkinan penggunaan panel tersebut di dalam kabin kenderaan. Tesis ini merupakan kajian permulaan dalam mengkaji hilang pancaran bunyi

Sound transmission through lined, composite panel structures: Transversely isotropic poro-elastic model

Science.gov (United States)

Kim, Jeong-Woo

A joint experimental and analytical investigation of the sound transmission loss (STL) and two-dimensional free wave propagation in composite sandwich panels is presented here. An existing panel, a Nomex honeycomb sandwich panel, was studied in detail. For the purpose of understanding the typical behavior of sandwich panels, a composite structure comprising two aluminum sheets with a relatively soft, poro-elastic foam core was also constructed and studied. The cores of both panels were modeled using an anisotropic (transversely isotropic) poro-elastic material theory. Several estimation methods were used to obtain the material properties of the honeycomb core and the skin plates to be used in the numerical calculations. Appropriate values selected from among the estimates were used in the STL and free wave propagation models. The prediction model was then verified in two ways: first, the calculated wave speeds and STL of a single poro-elastic layer were numerically verified by comparison with the predictions of a previously developed isotropic model. Secondly, to physically validate the transversely isotropic model, the measured STL and the phase speeds of the sandwich panels were compared with their predicted values. To analyze the actual treatment of a fuselage structure, multi-layered configurations, including a honeycomb panel and several layers such as air gaps, acoustic blankets and membrane partitions, were formulated. Then, to find the optimal solution for improving the sound barrier performance of an actual fuselage system, air layer depth and glass fiber lining effects were investigated by using these multi-layer models. By using the free wave propagation model, the first anti-symmetric and symmetric modes of the sandwich panels were characterized to allow the identification of the coincidence frequencies of the sandwich panel. The behavior of the STL could then be clearly explained by comparison with the free wave propagation solutions. By performing a

Unsound Sound

DEFF Research Database (Denmark)

Knakkergaard, Martin

2016-01-01

This article discusses the change in premise that digitally produced sound brings about and how digital technologies more generally have changed our relationship to the musical artifact, not simply in degree but in kind. It demonstrates how our acoustical conceptions are thoroughly challenged...... by the digital production of sound and, by questioning the ontological basis for digital sound, turns our understanding of the core term substance upside down....

Application of Carbon Nanotube Assemblies for Sound Generation and Heat Dissipation

Science.gov (United States)

Kozlov, Mikhail; Haines, Carter; Oh, Jiyoung; Lima, Marcio; Fang, Shaoli

2011-03-01

Nanotech approaches were explored for the efficient transformation of an electrical signal into sound, heat, cooling action, and mechanical strain. The studies are based on the aligned arrays of multi-walled carbon nanotubes (MWNT forests) that can be grown on various substrates using a conventional CVD technique. They form a three-dimensional conductive network that possesses uncommon electrical, thermal, acoustic and mechanical properties. When heated with an alternating current or a near-IR laser modulated in 0.01--20 kHz range, the nanotube forests produce loud, audible sound. High generated sound pressure and broad frequency response (beyond 20 kHz) show that the forests act as efficient thermo-acoustic (TA) transducers. They can generate intense third and fourth TA harmonics that reveal peculiar interference-like patterns from ac-dc voltage scans. A strong dependence of the patterns on forest height can be used for characterization of carbon nanotube assemblies and for evaluation of properties of thermal interfaces. Because of good coupling with surrounding air, the forests provide excellent dissipation of heat produced by IC chips. Thermoacoustic converters based on forests can be used for thermo- and photo-acoustic sound generation, amplification and noise cancellation.

Propagation of Finite Amplitude Sound in Multiple Waveguide Modes.

Science.gov (United States)

van Doren, Thomas Walter

1993-01-01

This dissertation describes a theoretical and experimental investigation of the propagation of finite amplitude sound in multiple waveguide modes. Quasilinear analytical solutions of the full second order nonlinear wave equation, the Westervelt equation, and the KZK parabolic wave equation are obtained for the fundamental and second harmonic sound fields in a rectangular rigid-wall waveguide. It is shown that the Westervelt equation is an acceptable approximation of the full nonlinear wave equation for describing guided sound waves of finite amplitude. A system of first order equations based on both a modal and harmonic expansion of the Westervelt equation is developed for waveguides with locally reactive wall impedances. Fully nonlinear numerical solutions of the system of coupled equations are presented for waveguides formed by two parallel planes which are either both rigid, or one rigid and one pressure release. These numerical solutions are compared to finite -difference solutions of the KZK equation, and it is shown that solutions of the KZK equation are valid only at frequencies which are high compared to the cutoff frequencies of the most important modes of propagation (i.e., for which sound propagates at small grazing angles). Numerical solutions of both the Westervelt and KZK equations are compared to experiments performed in an air-filled, rigid-wall, rectangular waveguide. Solutions of the Westervelt equation are in good agreement with experiment for low source frequencies, at which sound propagates at large grazing angles, whereas solutions of the KZK equation are not valid for these cases. At higher frequencies, at which sound propagates at small grazing angles, agreement between numerical solutions of the Westervelt and KZK equations and experiment is only fair, because of problems in specifying the experimental source condition with sufficient accuracy.

Aerosol composition in a stagnant air mass impacted by dense fogs: preliminary results

Energy Technology Data Exchange (ETDEWEB)

Jacob, D.J.; Munger, J.W.; Waldman, J.M.; Hoffman, M.R.

1984-01-01

Over the last two winters, our research group has been investigating the chemical composition of fogwater and haze aerosol during wintertime stagnation episodes in the San Joaquin Valley of California. The valley is encompassed by mountain ranges. During the winter a strong subsidence inversion based below the natural boundaries of the valley restricts the ventilation of the air masses below the inversion. The residence time of an air parcel in the valley under these stagnation conditions is on the order of 8 days. Because the trapped air is very humid, stagnation episodes are associated with a persistent thick haze and frequent widespread nighttime fogs. During the winter 1982-1983 the authors sampled fog and haze at one site (Bakersfield); results from this preliminary study have been discussed in detail in a previous report. In the winter 1983-1984 the scale of the program was expanded in order to test hypotheses formulated as a result of first year data. The present paper first reports briefly on the 1982-1983 results and outlines the essential conclusions. They then describe the large-scale experiment conducted during the winter of 1983-1984, and discuss some preliminary fogwater data.

Early Sound Symbolism for Vowel Sounds

Directory of Open Access Journals (Sweden)

Ferrinne Spector

2013-06-01

Full Text Available Children and adults consistently match some words (e.g., kiki to jagged shapes and other words (e.g., bouba to rounded shapes, providing evidence for non-arbitrary sound–shape mapping. In this study, we investigated the influence of vowels on sound–shape matching in toddlers, using four contrasting pairs of nonsense words differing in vowel sound (/i/ as in feet vs. /o/ as in boat and four rounded–jagged shape pairs. Crucially, we used reduplicated syllables (e.g., kiki vs. koko rather than confounding vowel sound with consonant context and syllable variability (e.g., kiki vs. bouba. Toddlers consistently matched words with /o/ to rounded shapes and words with /i/ to jagged shapes (p < 0.01. The results suggest that there may be naturally biased correspondences between vowel sound and shape.

Experimental study on utilization of air-borne jet sound in coolant leak detector

International Nuclear Information System (INIS)

Hayamizu, Y.; Kitahara, T.; Hayashi, T.; Nishimura, M.

1975-10-01

Studies have been undertaken to develop a new coolant leak detection method by the use of a microphone to pick up jet sound generated when pressurized high temperature water is discharged from a pressure boundary into the atmosphere. Leakage was simulated in three shapes, such as two machine-made circular holes and longitudinal and transverse slits in an inlet tube of a blowdown test facility. The measured power level of the jet sound was in agreement with theoretical values calculated from Lighthill's equation. In the study of utilization, this new method has been confirmed as applicable, and to be calculated theoretically for design on 'signal to noise ratio' evaluation. Detection of a small coolant leakage of 1 kg/sec is possible in a recirculation pump room which has large background noise from the pump if a suitable isolation wall, such as hot boxes, is installed between the monitored pipes and the pump. (auth.)

Sound Art and Spatial Practices: Situating Sound Installation Art Since 1958

OpenAIRE

Ouzounian, Gascia

2008-01-01

This dissertation examines the emergence and development ofsound installation art, an under-recognized tradition that hasdeveloped between music, architecture, and media art practicessince the late 1950s. Unlike many musical works, which are concernedwith organizing sounds in time, sound installations organize sounds inspace; they thus necessitate new theoretical and analytical modelsthat take into consideration the spatial situated-ness of sound. Existingdiscourses on “spatial sound” privile...

Sound field reconstruction using acousto-optic tomography

DEFF Research Database (Denmark)

Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

2012-01-01

When sound propagates through a medium, it results in pressure fluctuations that change the instantaneous density of the medium. Under such circumstances, the refractive index that characterizes the propagation of light is not constant, but influenced by the acoustic field. This kind of interaction...... the acousto-optic effect in air, and demonstrates that it can be measured with a laser Doppler vibrometer in the audible frequency range. The tomographic reconstruction is tested by means of computer simulations and measurements. The main features observed in the simulations are also recognized...

Ultracold Fermi and Bose gases and Spinless Bose Charged Sound Particles

Directory of Open Access Journals (Sweden)

Minasyan V.

2011-10-01

Full Text Available We propose a novel approach for investigation of the motion of Bose or Fermi liquid (or gas which consists of decoupled electrons and ions in the uppermost hyperfine state. Hence, we use such a concept as the fluctuation motion of “charged fluid particles” or “charged fluid points” representing a charged longitudinal elastic wave. In turn, this elastic wave is quantized by spinless longitudinal Bose charged sound particles with the rest mass m and charge e 0 . The existence of spinless Bose charged sound particles allows us to present a new model for description of Bose or Fermi liquid via a non-ideal Bose gas of charged sound particles . In this respect, we introduce a new postulation for the superfluid component of Bose or Fermi liquid determined by means of charged sound particles in the condensate, which may explain the results of experiments connected with ultra-cold Fermi gases of spin-polarized hydrogen, 6 Li and 40 K, and such a Bose gas as 87 Rb in the uppermost hyperfine state, where the Bose- Einstein condensation of charged sound particles is realized by tuning the magnetic field.

Sustainable Acoustic Metasurfaces for Sound Control

Directory of Open Access Journals (Sweden)

Paola Gori

2016-01-01

Full Text Available Sound attenuation with conventional acoustic materials is subject to the mass law and requires massive and bulky structures at low frequencies. A possible alternative solution is provided by the use of metamaterials, which are artificial materials properly engineered to obtain properties and characteristics that it is not possible to find in natural materials. Theory and applications of metamaterials, already consolidated in electromagnetism, can be extended to acoustics; in particular, they can be applied to improve the properties of acoustical panels. The design of acoustic metasurfaces that could effectively control transmitted sound in unconventional ways appears a significant subject to be investigated, given its wide-ranging possible applications. In this contribution, we investigate the application of a metasurface-inspired technique to achieve the acoustical insulation of an environment. The designed surface has subwavelength thickness and structuring and could be realized with cheap, lightweight and sustainable materials. We present a few examples of such structures and analyze their acoustical behavior by means of full-wave simulations.

Safety of the HyperSound® Audio System in subjects with normal hearing

Directory of Open Access Journals (Sweden)

Ritvik P. Mehta

2015-11-01

Full Text Available The objective of the study was to assess the safety of the HyperSound® Audio System (HSS, a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered preexposure and post-exposure test design. We investigated primary and secondary outcome measures: i temporary threshold shift (TTS, defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs >10 dB at two or more frequencies; ii presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions.

Safety of the HyperSound® Audio System in Subjects with Normal Hearing.

Science.gov (United States)

Mehta, Ritvik P; Mattson, Sara L; Kappus, Brian A; Seitzman, Robin L

2015-06-11

The objective of the study was to assess the safety of the HyperSound® Audio System (HSS), a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered pre-exposure and post-exposure test design. We investigated primary and secondary outcome measures: i) temporary threshold shift (TTS), defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs) >10 dB at two or more frequencies; ii) presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire) followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions.

Geotechnical issues and guidelines for storage of compressed air in excavated hard rock caverns

Energy Technology Data Exchange (ETDEWEB)

Allen, R.D.; Doherty, T.J.; Fossum, A.F.

1982-04-01

The results of a literature survey on the stability of excavated hard rock caverns are presented. The objective of the study was to develop geotechnical criteria for the design of compressed air energy storage (CAES) caverns in hard rock formations. These criteria involve geologic, hydrological, geochemical, geothermal, and in situ stress state characteristics of generic rock masses. Their relevance to CAES caverns, and the identification of required research areas, are identified throughout the text. This literature survey and analysis strongly suggests that the chief geotechnical issues for the development and operation of CAES caverns in hard rock are impermeability for containment, stability for sound openings, and hydrostatic balance.

Sound a very short introduction

CERN Document Server

Goldsmith, Mike

2015-01-01

Sound is integral to how we experience the world, in the form of noise as well as music. But what is sound? What is the physical basis of pitch and harmony? And how are sound waves exploited in musical instruments? Sound: A Very Short Introduction looks at the science of sound and the behaviour of sound waves with their different frequencies. It also explores sound in different contexts, covering the audible and inaudible, sound underground and underwater, acoustic and electronic sound, and hearing in humans and animals. It concludes with the problem of sound out of place—noise and its reduction.

Neonatal Presentation of an Air-Filled Neck Mass that Enlarges with Valsalva: A Case Report

Science.gov (United States)

Patel, Jasminkumar Bharatbhai; Kilbride, Howard; Paulson, Lorien

2015-01-01

Branchial cleft cysts are common causes of congenital neck masses in the pediatric population. However, neonatal presentation of branchial cleft cysts is uncommon, but recognizable secondary to acute respiratory distress from airway compression or complications secondary to infection. We report a 1-day-old infant presenting with an air-filled neck mass that enlarged with Valsalva and was not associated with respiratory distress. The infant was found to have a third branchial cleft cyst with an internal opening into the pyriform sinus. The cyst was conservatively managed with endoscopic surgical decompression and cauterization of the tract and opening. We review the embryology of branchial cleft cysts and current management. PMID:26495186

Acoustic levitation of soap bubbles in air: Beyond the half-wavelength limit of sound

Science.gov (United States)

Zang, Duyang; Lin, Kejun; Li, Lin; Chen, Zhen; Li, Xiaoguang; Geng, Xingguo

2017-03-01

We report on the behavior of levitated soap bubbles in a single-axis acoustic field. For a single bubble, its surface in the polar regions is under compression, but in the equatorial region, it is under suction. Levitation becomes unstable when the height of the bubble approaches half the wavelength of the sound wave because horizontal fluctuations lead to a negative recovery force and a negative levitation force. Vertically stacked double bubbles notably can be stable under levitation if their total vertical length is ˜5λ/6, significantly beyond λ/2 in consequence of the formation of a toroidal high-pressure region around the waist of the two bubbles. Our results provide a deeper insight into the stability of acoustic levitation and the coupling between bubbles and sound field.

Chemical composition of air masses transported from Asia to the U.S. West Coast during ITCT 2K2: Fossil fuel combustion versus biomass-burning signatures

Science.gov (United States)

de Gouw, J. A.; Cooper, O. R.; Warneke, C.; Hudson, P. K.; Fehsenfeld, F. C.; Holloway, J. S.; Hübler, G.; Nicks, D. K., Jr.; Nowak, J. B.; Parrish, D. D.; Ryerson, T. B.; Atlas, E. L.; Donnelly, S. G.; Schauffler, S. M.; Stroud, V.; Johnson, K.; Carmichael, G. R.; Streets, D. G.

2004-12-01

As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) to propane (C3H8), and, on May 5, the percentage of particles measured by the particle analysis by laser mass spectrometry (PALMS) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast over a range of latitudes and altitudes for the entire ITCT 2K2 period, showed that air masses from Southeast Asia and China were generally observed at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for Southeast Asia. Combined with the origin of the air masses versus altitude, this qualitatively explains the increase with altitude, averaged over the whole ITCT 2K2 period, of the different biomass-burning indicators.

Sound transmission through lightweight double-leaf partitions: theoretical modelling

Science.gov (United States)

Wang, J.; Lu, T. J.; Woodhouse, J.; Langley, R. S.; Evans, J.

2005-09-01

This paper presents theoretical modelling of the sound transmission loss through double-leaf lightweight partitions stiffened with periodically placed studs. First, by assuming that the effect of the studs can be replaced with elastic springs uniformly distributed between the sheathing panels, a simple smeared model is established. Second, periodic structure theory is used to develop a more accurate model taking account of the discrete placing of the studs. Both models treat incident sound waves in the horizontal plane only, for simplicity. The predictions of the two models are compared, to reveal the physical mechanisms determining sound transmission. The smeared model predicts relatively simple behaviour, in which the only conspicuous features are associated with coincidence effects with the two types of structural wave allowed by the partition model, and internal resonances of the air between the panels. In the periodic model, many more features are evident, associated with the structure of pass- and stop-bands for structural waves in the partition. The models are used to explain the effects of incidence angle and of the various system parameters. The predictions are compared with existing test data for steel plates with wooden stiffeners, and good agreement is obtained.

Air trapping on computed tomography images of healthy individuals: effects of respiration and body mass index

International Nuclear Information System (INIS)

Hashimoto, M.; Tate, E.; Watarai, J.; Sasaki, M.

2006-01-01

Aim: To evaluate the relationships of changes in the lung area during respiration and of individual body mass index (BMI) to air trapping on expiratory computed tomography (CT) in young non-smoking adults of either gender. Methods: The volunteers were 10 women and 10 men (mean age 25.7 years) who were healthy lifelong non-smokers. We obtained both end-inspiratory and end-expiratory CT images at three levels: the upper, middle and lower lung. The ratio of cross-sectional lung area upon expiration to cross-sectional lung area upon inspiration (lung area ratio) was determined for each lung at each of the three levels. In cases showing air trapping, we calculated the percentage of area of air in relation to the total lung area in each section. BMI was calculated for each participant. Results: Air trapping was present in dependent areas of the lungs of 6 women and 5 men. The mean percentage of area of air trapped was statistically greater for men (9.8 ± 9.2%) than for women (4.9 ± 5.2%). The mean lung area ratio was 0.52 ± 0 14 among volunteers with air trapping (66 sections) and 0.69 ± 0.12 among those without air trapping (54 sections) (p < 0.001). At each lung level, the mean lung area ratio was greater in individuals with air trapping than in those without. Mean BMI was also greater in these people (p = 0.009). Conclusion: Change in the respiratory lung area and BMI contribute to development of air trapping

A study on the effects of system pressure on heat and mass transfer rates of an air cooler

International Nuclear Information System (INIS)

Jung, Hyung Ho

2002-01-01

In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements

What is Sound?

OpenAIRE

Nelson, Peter

2014-01-01

What is sound? This question is posed in contradiction to the every-day understanding that sound is a phenomenon apart from us, to be heard, made, shaped and organised. Thinking through the history of computer music, and considering the current configuration of digital communi-cations, sound is reconfigured as a type of network. This network is envisaged as non-hierarchical, in keeping with currents of thought that refuse to prioritise the human in the world. The relationship of sound to musi...

Broadcast sound technology

CERN Document Server

Talbot-Smith, Michael

1990-01-01

Broadcast Sound Technology provides an explanation of the underlying principles of modern audio technology. Organized into 21 chapters, the book first describes the basic sound; behavior of sound waves; aspects of hearing, harming, and charming the ear; room acoustics; reverberation; microphones; phantom power; loudspeakers; basic stereo; and monitoring of audio signal. Subsequent chapters explore the processing of audio signal, sockets, sound desks, and digital audio. Analogue and digital tape recording and reproduction, as well as noise reduction, are also explained.

Propagation of sound

DEFF Research Database (Denmark)

Wahlberg, Magnus; Larsen, Ole Næsbye

2017-01-01

properties can be modified by sound absorption, refraction, and interference from multi paths caused by reflections.The path from the source to the receiver may be bent due to refraction. Besides geometrical attenuation, the ground effect and turbulence are the most important mechanisms to influence...... communication sounds for airborne acoustics and bottom and surface effects for underwater sounds. Refraction becomes very important close to shadow zones. For echolocation signals, geometric attenuation and sound absorption have the largest effects on the signals....

Making fictions sound real

DEFF Research Database (Denmark)

Langkjær, Birger

2010-01-01

This article examines the role that sound plays in making fictions perceptually real to film audiences, whether these fictions are realist or non-realist in content and narrative form. I will argue that some aspects of film sound practices and the kind of experiences they trigger are related...... to basic rules of human perception, whereas others are more properly explained in relation to how aesthetic devices, including sound, are used to characterise the fiction and thereby make it perceptually real to its audience. Finally, I will argue that not all genres can be defined by a simple taxonomy...... of sounds. Apart from an account of the kinds of sounds that typically appear in a specific genre, a genre analysis of sound may also benefit from a functionalist approach that focuses on how sounds can make both realist and non-realist aspects of genres sound real to audiences....

Sonar sound groups and increased terminal buzz duration reflect task complexity in hunting bats

DEFF Research Database (Denmark)

Hulgard, K.; Ratcliffe, J. M.

2016-01-01

to prey under presumably more difficult conditions. Specifically, we found Daubenton's bats, Myotis daubentonii, produced longer buzzes when aerial-hawking versus water-trawling prey, but that bats taking revolving air- and water-borne prey produced more sonar sound groups than did the bats when taking...

Computerised respiratory sounds can differentiate smokers and non-smokers.

Science.gov (United States)

Oliveira, Ana; Sen, Ipek; Kahya, Yasemin P; Afreixo, Vera; Marques, Alda

2017-06-01

Cigarette smoking is often associated with the development of several respiratory diseases however, if diagnosed early, the changes in the lung tissue caused by smoking may be reversible. Computerised respiratory sounds have shown to be sensitive to detect changes within the lung tissue before any other measure, however it is unknown if it is able to detect changes in the lungs of healthy smokers. This study investigated the differences between computerised respiratory sounds of healthy smokers and non-smokers. Healthy smokers and non-smokers were recruited from a university campus. Respiratory sounds were recorded simultaneously at 6 chest locations (right and left anterior, lateral and posterior) using air-coupled electret microphones. Airflow (1.0-1.5 l/s) was recorded with a pneumotachograph. Breathing phases were detected using airflow signals and respiratory sounds with validated algorithms. Forty-four participants were enrolled: 18 smokers (mean age 26.2, SD = 7 years; mean FEV 1 % predicted 104.7, SD = 9) and 26 non-smokers (mean age 25.9, SD = 3.7 years; mean FEV 1 % predicted 96.8, SD = 20.2). Smokers presented significantly higher frequency at maximum sound intensity during inspiration [(M = 117, SD = 16.2 Hz vs. M = 106.4, SD = 21.6 Hz; t(43) = -2.62, p = 0.0081, d z  = 0.55)], lower expiratory sound intensities (maximum intensity: [(M = 48.2, SD = 3.8 dB vs. M = 50.9, SD = 3.2 dB; t(43) = 2.68, p = 0.001, d z  = -0.78)]; mean intensity: [(M = 31.2, SD = 3.6 dB vs. M = 33.7,SD = 3 dB; t(43) = 2.42, p = 0.001, d z  = 0.75)] and higher number of inspiratory crackles (median [interquartile range] 2.2 [1.7-3.7] vs. 1.5 [1.2-2.2], p = 0.081, U = 110, r = -0.41) than non-smokers. Significant differences between computerised respiratory sounds of smokers and non-smokers have been found. Changes in respiratory sounds are often the earliest sign of disease. Thus, computerised respiratory sounds

Sound sensitivity of neurons in rat hippocampus during performance of a sound-guided task

Science.gov (United States)

Vinnik, Ekaterina; Honey, Christian; Schnupp, Jan; Diamond, Mathew E.

2012-01-01

To investigate how hippocampal neurons encode sound stimuli, and the conjunction of sound stimuli with the animal's position in space, we recorded from neurons in the CA1 region of hippocampus in rats while they performed a sound discrimination task. Four different sounds were used, two associated with water reward on the right side of the animal and the other two with water reward on the left side. This allowed us to separate neuronal activity related to sound identity from activity related to response direction. To test the effect of spatial context on sound coding, we trained rats to carry out the task on two identical testing platforms at different locations in the same room. Twenty-one percent of the recorded neurons exhibited sensitivity to sound identity, as quantified by the difference in firing rate for the two sounds associated with the same response direction. Sensitivity to sound identity was often observed on only one of the two testing platforms, indicating an effect of spatial context on sensory responses. Forty-three percent of the neurons were sensitive to response direction, and the probability that any one neuron was sensitive to response direction was statistically independent from its sensitivity to sound identity. There was no significant coding for sound identity when the rats heard the same sounds outside the behavioral task. These results suggest that CA1 neurons encode sound stimuli, but only when those sounds are associated with actions. PMID:22219030

Experimental and theoretical sound transmission. [reduction of interior noise in aircraft

Science.gov (United States)

Roskam, J.; Muirhead, V. U.; Smith, H. W.; Durenberger, D. W.

1978-01-01

The capabilities of the Kansas University- Flight Research Center for investigating panel sound transmission as a step toward the reduction of interior noise in general aviation aircraft were discussed. Data obtained on panels with holes, on honeycomb panels, and on various panel treatments at normal incidence were documented. The design of equipment for panel transmission loss tests at nonnormal (slanted) sound incidence was described. A comprehensive theory-based prediction method was developed and shows good agreement with experimental observations of the stiffness controlled, the region, the resonance controlled region, and the mass-law region of panel vibration.

Broadband low-frequency sound isolation by lightweight adaptive metamaterials

Science.gov (United States)

Liao, Yunhong; Chen, Yangyang; Huang, Guoliang; Zhou, Xiaoming

2018-03-01

Blocking broadband low-frequency airborne noises is highly desirable in lots of engineering applications, while it is extremely difficult to be realized with lightweight materials and/or structures. Recently, a new class of lightweight adaptive metamaterials with hybrid shunting circuits has been proposed, demonstrating super broadband structure-borne bandgaps. In this study, we aim at examining their potentials in broadband sound isolation by establishing an analytical model that rigorously combines the piezoelectric dynamic couplings between adaptive metamaterials and acoustics. Sound transmission loss of the adaptive metamaterial is investigated with respect to both the frequency and angular spectrum to demonstrate their sound-insulation effects. We find that efficient sound isolation can indeed be pursued in the broadband bi-spectrum for not only the case of the small resonator's periodicity where only one mode relevant to the mass-spring resonance exists, but also for the large-periodicity scenario, so that the total weight can be even lighter, in which the multiple plate-resonator coupling modes appear. In the latter case, the negative spring stiffness provided by the piezoelectric stack has been utilized to suppress the resonance-induced high acoustic transmission. Such kinds of adaptive metamaterials could open a new approach for broadband noise isolation with extremely lightweight structures.

The French balloon and sounding rocket space program

Science.gov (United States)

Coutin/Faye, S.; Sadourny, I.

1987-08-01

Stratospheric and long duration flight balloon programs are outlined. Open stratospheric balloons up to 1 million cu m volume are used to carry astronomy, solar system, aeronomy, stratosphere, biology, space physics, and geophysics experiments. The long duration balloons can carry 50 kg payloads at 20 to 30 km altitude for 10 days to several weeks. Pressurized stratospheric balloons, and infrared hot air balloons are used. They are used to study the dynamics of stratospheric waves and atmospheric water vapor. Laboratories participating in sounding rocket programs are listed.

33 CFR 167.1702 - In Prince William Sound: Prince William Sound Traffic Separation Scheme.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false In Prince William Sound: Prince William Sound Traffic Separation Scheme. 167.1702 Section 167.1702 Navigation and Navigable Waters COAST....1702 In Prince William Sound: Prince William Sound Traffic Separation Scheme. The Prince William Sound...

A Physical Model of Mass Ejection in Failed Supernovae

Science.gov (United States)

Coughlin, Eric R.; Quataert, Eliot; Fernández, Rodrigo; Kasen, Daniel

2018-03-01

During the core collapse of massive stars, the formation of the protoneutron star is accompanied by the emission of a significant amount of mass-energy (˜0.3 M⊙) in the form of neutrinos. This mass-energy loss generates an outward-propagating pressure wave that steepens into a shock near the stellar surface, potentially powering a weak transient associated with an otherwise-failed supernova. We analytically investigate this mass-loss-induced wave generation and propagation. Heuristic arguments provide an accurate estimate of the amount of energy contained in the outgoing sound pulse. We then develop a general formalism for analyzing the response of the star to centrally concentrated mass loss in linear perturbation theory. To build intuition, we apply this formalism to polytropic stellar models, finding qualitative and quantitative agreement with simulations and heuristic arguments. We also apply our results to realistic pre-collapse massive star progenitors (both giants and compact stars). Our analytic results for the sound pulse energy, excitation radius, and steepening in the stellar envelope are in good agreement with full time-dependent hydrodynamic simulations. We show that prior to the sound pulses arrival at the stellar photosphere, the photosphere has already reached velocities ˜20 - 100% of the local sound speed, thus likely modestly decreasing the stellar effective temperature prior to the star disappearing. Our results provide important constraints on the physical properties and observational appearance of failed supernovae.

A physical model of mass ejection in failed supernovae

Science.gov (United States)

Coughlin, Eric R.; Quataert, Eliot; Fernández, Rodrigo; Kasen, Daniel

2018-06-01

During the core collapse of massive stars, the formation of the proto-neutron star is accompanied by the emission of a significant amount of mass energy (˜0.3 M⊙) in the form of neutrinos. This mass-energy loss generates an outward-propagating pressure wave that steepens into a shock near the stellar surface, potentially powering a weak transient associated with an otherwise-failed supernova. We analytically investigate this mass-loss-induced wave generation and propagation. Heuristic arguments provide an accurate estimate of the amount of energy contained in the outgoing sound pulse. We then develop a general formalism for analysing the response of the star to centrally concentrated mass loss in linear perturbation theory. To build intuition, we apply this formalism to polytropic stellar models, finding qualitative and quantitative agreement with simulations and heuristic arguments. We also apply our results to realistic pre-collapse massive star progenitors (both giants and compact stars). Our analytic results for the sound pulse energy, excitation radius, and steepening in the stellar envelope are in good agreement with full time-dependent hydrodynamic simulations. We show that prior to the sound pulses arrival at the stellar photosphere, the photosphere has already reached velocities ˜ 20-100 per cent of the local sound speed, thus likely modestly decreasing the stellar effective temperature prior to the star disappearing. Our results provide important constraints on the physical properties and observational appearance of failed supernovae.

The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

Directory of Open Access Journals (Sweden)

Gorji-Bandpy Mofid

2012-04-01

Full Text Available This paper presents a computational fluid dynamics (CFD calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

Hybrid waste filler filled bio-polymer foam composites for sound absorbent materials

Science.gov (United States)

Rus, Anika Zafiah M.; Azahari, M. Shafiq M.; Kormin, Shaharuddin; Soon, Leong Bong; Zaliran, M. Taufiq; Ahraz Sadrina M. F., L.

2017-09-01

Sound absorption materials are one of the major requirements in many industries with regards to the sound insulation developed should be efficient to reduce sound. This is also important to contribute in economically ways of producing sound absorbing materials which is cheaper and user friendly. Thus, in this research, the sound absorbent properties of bio-polymer foam filled with hybrid fillers of wood dust and waste tire rubber has been investigated. Waste cooking oil from crisp industries was converted into bio-monomer, filled with different proportion ratio of fillers and fabricated into bio-polymer foam composite. Two fabrication methods is applied which is the Close Mold Method (CMM) and Open Mold Method (OMM). A total of four bio-polymer foam composite samples were produce for each method used. The percentage of hybrid fillers; mixture of wood dust and waste tire rubber of 2.5 %, 5.0%, 7.5% and 10% weight to weight ration with bio-monomer. The sound absorption of the bio-polymer foam composites samples were tested by using the impedance tube test according to the ASTM E-1050 and Scanning Electron Microscope to determine the morphology and porosity of the samples. The sound absorption coefficient (α) at different frequency range revealed that the polymer foam of 10.0 % hybrid fillers shows highest α of 0.963. The highest hybrid filler loading contributing to smallest pore sizes but highest interconnected pores. This also revealed that when highly porous material is exposed to incident sound waves, the air molecules at the surface of the material and within the pores of the material are forced to vibrate and loses some of their original energy. This is concluded that the suitability of bio-polymer foam filled with hybrid fillers to be used in acoustic application of automotive components such as dashboards, door panels, cushion and etc.

Sounds Exaggerate Visual Shape

Science.gov (United States)

Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

2012-01-01

While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

Sound transmission through triple-panel structures lined with poroelastic materials

Science.gov (United States)

Liu, Yu

2015-03-01

In this paper, previous theories on the prediction of sound transmission loss for a double-panel structure lined with poroelastic materials are extended to address the problem of a triple-panel structure. Six typical configurations are considered for a triple-panel structure based on the method of coupling the porous layers to the facing panels which determines critically the sound insulation performance of the system. The transfer matrix method is employed to solve the system by applying appropriate types of boundary conditions for these configurations. The transmission loss of the triple-panel structures in a diffuse sound field is calculated as a function of frequency and compared with that of corresponding double-panel structures. Generally, the triple-panel structure with poroelastic linings has superior acoustic performance to the double-panel counterpart, remarkably in the mid-high frequency range and possibly at low frequencies, by selecting appropriate configurations in which those with two air gaps in the structure exhibit the best overall performance over the entire frequency range. The poroelastic lining significantly lowers the cut-on frequency above which the triple-panel structure exhibits noticeably higher transmission loss. Compared with a double-panel structure, the wider range of system parameters for a triple-panel structure due to the additional partition provides more design space for tuning the sound insulation performance. Despite the increased structural complexity, the triple-panel structure lined with poroelastic materials has the obvious advantages in sound transmission loss while without the penalties in weight and volume, and is hence a promising replacement for the widely used double-panel sandwich structure.

Sound Zones

DEFF Research Database (Denmark)

Møller, Martin Bo; Olsen, Martin

2017-01-01

Sound zones, i.e. spatially confined regions of individual audio content, can be created by appropriate filtering of the desired audio signals reproduced by an array of loudspeakers. The challenge of designing filters for sound zones is twofold: First, the filtered responses should generate...... an acoustic separation between the control regions. Secondly, the pre- and post-ringing as well as spectral deterioration introduced by the filters should be minimized. The tradeoff between acoustic separation and filter ringing is the focus of this paper. A weighted L2-norm penalty is introduced in the sound...

A description of externally recorded womb sounds in human subjects during gestation.

Science.gov (United States)

Parga, Joanna J; Daland, Robert; Kesavan, Kalpashri; Macey, Paul M; Zeltzer, Lonnie; Harper, Ronald M

2018-01-01

Reducing environmental noise benefits premature infants in neonatal intensive care units (NICU), but excessive reduction may lead to sensory deprivation, compromising development. Instead of minimal noise levels, environments that mimic intrauterine soundscapes may facilitate infant development by providing a sound environment reflecting fetal life. This soundscape may support autonomic and emotional development in preterm infants. We aimed to assess the efficacy and feasibility of external non-invasive recordings in pregnant women, endeavoring to capture intra-abdominal or womb sounds during pregnancy with electronic stethoscopes and build a womb sound library to assess sound trends with gestational development. We also compared these sounds to popular commercial womb sounds marketed to new parents. Intra-abdominal sounds from 50 mothers in their second and third trimester (13 to 40 weeks) of pregnancy were recorded for 6 minutes in a quiet clinic room with 4 electronic stethoscopes, placed in the right upper and lower quadrants, and left upper and lower quadrants of the abdomen. These recording were partitioned into 2-minute intervals in three different positions: standing, sitting and lying supine. Maternal and gestational age, Body Mass Index (BMI) and time since last meal were collected during recordings. Recordings were analyzed using long-term average spectral and waveform analysis, and compared to sounds from non-pregnant abdomens and commercially-marketed womb sounds selected for their availability, popularity, and claims they mimic the intrauterine environment. Maternal sounds shared certain common characteristics, but varied with gestational age. With fetal development, the maternal abdomen filtered high (500-5,000 Hz) and mid-frequency (100-500 Hz) energy bands, but no change appeared in contributions from low-frequency signals (10-100 Hz) with gestational age. Variation appeared between mothers, suggesting a resonant chamber role for intra

Can road traffic mask sound from wind turbines? Response to wind turbine sound at different levels of road traffic sound

International Nuclear Information System (INIS)

Pedersen, Eja; Berg, Frits van den; Bakker, Roel; Bouma, Jelte

2010-01-01

Wind turbines are favoured in the switch-over to renewable energy. Suitable sites for further developments could be difficult to find as the sound emitted from the rotor blades calls for a sufficient distance to residents to avoid negative effects. The aim of this study was to explore if road traffic sound could mask wind turbine sound or, in contrast, increases annoyance due to wind turbine noise. Annoyance of road traffic and wind turbine noise was measured in the WINDFARMperception survey in the Netherlands in 2007 (n=725) and related to calculated levels of sound. The presence of road traffic sound did not in general decrease annoyance with wind turbine noise, except when levels of wind turbine sound were moderate (35-40 dB(A) Lden) and road traffic sound level exceeded that level with at least 20 dB(A). Annoyance with both noises was intercorrelated but this correlation was probably due to the influence of individual factors. Furthermore, visibility and attitude towards wind turbines were significantly related to noise annoyance of modern wind turbines. The results can be used for the selection of suitable sites, possibly favouring already noise exposed areas if wind turbine sound levels are sufficiently low.

Fin whale sound reception mechanisms: skull vibration enables low-frequency hearing.

Directory of Open Access Journals (Sweden)

Ted W Cranford

Full Text Available Hearing mechanisms in baleen whales (Mysticeti are essentially unknown but their vocalization frequencies overlap with anthropogenic sound sources. Synthetic audiograms were generated for a fin whale by applying finite element modeling tools to X-ray computed tomography (CT scans. We CT scanned the head of a small fin whale (Balaenoptera physalus in a scanner designed for solid-fuel rocket motors. Our computer (finite element modeling toolkit allowed us to visualize what occurs when sounds interact with the anatomic geometry of the whale's head. Simulations reveal two mechanisms that excite both bony ear complexes, (1 the skull-vibration enabled bone conduction mechanism and (2 a pressure mechanism transmitted through soft tissues. Bone conduction is the predominant mechanism. The mass density of the bony ear complexes and their firmly embedded attachments to the skull are universal across the Mysticeti, suggesting that sound reception mechanisms are similar in all baleen whales. Interactions between incident sound waves and the skull cause deformations that induce motion in each bony ear complex, resulting in best hearing sensitivity for low-frequency sounds. This predominant low-frequency sensitivity has significant implications for assessing mysticete exposure levels to anthropogenic sounds. The din of man-made ocean noise has increased steadily over the past half century. Our results provide valuable data for U.S. regulatory agencies and concerned large-scale industrial users of the ocean environment. This study transforms our understanding of baleen whale hearing and provides a means to predict auditory sensitivity across a broad spectrum of sound frequencies.

Optimal design of sound absorbing systems with microperforated panels

Science.gov (United States)

Kim, Nicholas Nakjoo

As the development of technology makes economic prosperity and life more convenient, people now desire a higher quality of life. This quality of life is based not only on the convenience in their life but also on clean and eco-friendly environments. To meet that requirement, much research is being performed in many areas of eco-friendly technology, such as renewable energy, biodegradable content, and batteries for electronic vehicles. This tendency is also obvious in the acoustics area, where there are continuing attempts to replace fiber-glass sound absorbers with fiber-free materials. The combination of microperfoated panels (MPP) (one of the fiber-free sound absorbing materials), usually in the form of a thin panel with small holes, and an air backing may be one of the preferred solutions. These panels can be designed in many ways, and usually feature many small (sub-millimeter) holes and typically surface porosities on the order of 1 percent. The detailed acoustical properties of MPPs depend on their hole shape, the hole diameter, the thickness of the panel, the overall porosity of the perforated film, the film's mass per unit area, and the depth of the backing air cavity. Together, these parameters control the absorption peak location and the magnitude of the absorption coefficient (and the magnitude of the transmission loss in barrier applications). By an appropriate choice of these parameters good absorption performance can be achieved in a frequency range one or two octaves wide. That kind of solution may be adequate when it is necessary to control sound only in a specified frequency range (in the speech interference range, for example). However, in order to provide appropriate noise control solutions over a broader range of frequencies, it is necessary to design systems featuring multiple-layers of MPPs, thus creating what amounts to a multi-degree-of-freedom system and so expanding the range over which good absorption can be obtained. In this research

Structure-borne sound structural vibrations and sound radiation at audio frequencies

CERN Document Server

Cremer, L; Petersson, Björn AT

2005-01-01

Structure-Borne Sound"" is a thorough introduction to structural vibrations with emphasis on audio frequencies and the associated radiation of sound. The book presents in-depth discussions of fundamental principles and basic problems, in order to enable the reader to understand and solve his own problems. It includes chapters dealing with measurement and generation of vibrations and sound, various types of structural wave motion, structural damping and its effects, impedances and vibration responses of the important types of structures, as well as with attenuation of vibrations, and sound radi

International system of units traceable results of Hg mass concentration at saturation in air from a newly developed measurement procedure.

Science.gov (United States)

Quétel, Christophe R; Zampella, Mariavittoria; Brown, Richard J C; Ent, Hugo; Horvat, Milena; Paredes, Eduardo; Tunc, Murat

2014-08-05

Data most commonly used at present to calibrate measurements of mercury vapor concentrations in air come from a relationship known as the "Dumarey equation". It uses a fitting relationship to experimental results obtained nearly 30 years ago. The way these results relate to the international system of units (SI) is not known. This has caused difficulties for the specification and enforcement of limit values for mercury concentrations in air and in emissions to air as part of national or international legislation. Furthermore, there is a significant discrepancy (around 7% at room temperature) between the Dumarey data and data calculated from results of mercury vapor pressure measurements in the presence of only liquid mercury. As an attempt to solve some of these problems, a new measurement procedure is described for SI traceable results of gaseous Hg concentrations at saturation in milliliter samples of air. The aim was to propose a scheme as immune as possible to analytical biases. It was based on isotope dilution (ID) in the liquid phase with the (202)Hg enriched certified reference material ERM-AE640 and measurements of the mercury isotope ratios in ID blends, subsequent to a cold vapor generation step, by inductively coupled plasma mass spectrometry. The process developed involved a combination of interconnected valves and syringes operated by computer controlled pumps and ensured continuity under closed circuit conditions from the air sampling stage onward. Quantitative trapping of the gaseous mercury in the liquid phase was achieved with 11.5 μM KMnO4 in 2% HNO3. Mass concentrations at saturation found from five measurements under room temperature conditions were significantly higher (5.8% on average) than data calculated from the Dumarey equation, but in agreement (-1.2% lower on average) with data based on mercury vapor pressure measurement results. Relative expanded combined uncertainties were estimated following a model based approach. They ranged from 2

Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

Science.gov (United States)

Kahn, Ralph A.

2012-01-01

The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

In-air hearing of the great cormorant (Phalacrocorax carbo)

DEFF Research Database (Denmark)

Maxwell, Alyssa; Hansen, Kirstin Anderson; Ortiz, Sara Torres

2017-01-01

Many aquatic birds use sounds extensively for in-air communication. Regardless of this, we know very little about their hearing abilities. The in-air audiogram of a male adult great cormorant (Phalacrocorax carbo) was determined using psychophysical methods (method of constants). Hearing thresholds...... as to assess the impact of increasing in-air anthropogenic noise levels on cormorants and other aquatic birds....

InfoSound

DEFF Research Database (Denmark)

Sonnenwald, Diane H.; Gopinath, B.; Haberman, Gary O.

1990-01-01

The authors explore ways to enhance users' comprehension of complex applications using music and sound effects to present application-program events that are difficult to detect visually. A prototype system, Infosound, allows developers to create and store musical sequences and sound effects with...

The Sound of Science

Science.gov (United States)

Merwade, Venkatesh; Eichinger, David; Harriger, Bradley; Doherty, Erin; Habben, Ryan

2014-01-01

While the science of sound can be taught by explaining the concept of sound waves and vibrations, the authors of this article focused their efforts on creating a more engaging way to teach the science of sound--through engineering design. In this article they share the experience of teaching sound to third graders through an engineering challenge…

Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

Science.gov (United States)

Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

2012-01-01

During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote

Computerized Respiratory Sounds: Novel Outcomes for Pulmonary Rehabilitation in COPD.

Science.gov (United States)

Jácome, Cristina; Marques, Alda

2017-02-01

Computerized respiratory sounds are a simple and noninvasive measure to assess lung function. Nevertheless, their potential to detect changes after pulmonary rehabilitation (PR) is unknown and needs clarification if respiratory acoustics are to be used in clinical practice. Thus, this study investigated the short- and mid-term effects of PR on computerized respiratory sounds in subjects with COPD. Forty-one subjects with COPD completed a 12-week PR program and a 3-month follow-up. Secondary outcome measures included dyspnea, self-reported sputum, FEV 1 , exercise tolerance, self-reported physical activity, health-related quality of life, and peripheral muscle strength. Computerized respiratory sounds, the primary outcomes, were recorded at right/left posterior chest using 2 stethoscopes. Air flow was recorded with a pneumotachograph. Normal respiratory sounds, crackles, and wheezes were analyzed with validated algorithms. There was a significant effect over time in all secondary outcomes, with the exception of FEV 1 and of the impact domain of the St George Respiratory Questionnaire. Inspiratory and expiratory median frequencies of normal respiratory sounds in the 100-300 Hz band were significantly lower immediately (-2.3 Hz [95% CI -4 to -0.7] and -1.9 Hz [95% CI -3.3 to -0.5]) and at 3 months (-2.1 Hz [95% CI -3.6 to -0.7] and -2 Hz [95% CI -3.6 to -0.5]) post-PR. The mean number of expiratory crackles (-0.8, 95% CI -1.3 to -0.3) and inspiratory wheeze occupation rate (median 5.9 vs 0) were significantly lower immediately post-PR. Computerized respiratory sounds were sensitive to short- and mid-term effects of PR in subjects with COPD. These findings are encouraging for the clinical use of respiratory acoustics. Future research is needed to strengthen these findings and explore the potential of computerized respiratory sounds to assess the effectiveness of other clinical interventions in COPD. Copyright © 2017 by Daedalus Enterprises.

Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

Directory of Open Access Journals (Sweden)

S. Amos-Abanyie

2013-01-01

Full Text Available Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+ simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT. An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses.

Air pollution episodes in Stockholm regional background air due to sources in Europe and their effects on human population

Energy Technology Data Exchange (ETDEWEB)

Andersson, C. [Swedish Meteorological and Hydrological Inst., Norrkoping (Sweden)], E-mail: camilla.andersson@smhi.se; Joensson, O. [Stockholm Univ. (Sweden). Dept. of Applied Environmental Science; Forsberg, B. [Umea Univ. (Sweden), Occupational and Environmental Medicine; Johansson, C. [Environmental and Health Administration, Stockholm (Sweden)

2013-09-01

Using air quality measurements, we categorized air pollution according to source sectors in a rural background environment in southern Sweden based on hourly air-mass backward trajectories during 1997-2010. Concentrations of fine (PM{sub 2.5}) and sum of fine and coarse particulate matter (PM{sub 10}), accumulation mode particle number, black carbon and surface ozone were 4.0, 3.9, 4.5, 6.8 and 1.3 times higher, respectively, in air masses from the southeast as compared with those in air masses from the cleanest sector in the northwest, consistent with air-mass transport over areas with relatively high emissions of primary particulate matter (PM) and secondary PM precursors. The highest ultrafine particle numbers were associated with clean air from the northwest. We estimate that almost 7.8% and 0.6% higher premature human mortality is caused by PM{sub 2.5} and ozone exposure, respectively, when air originates from the southeast as compared with that when air originates from the northwest. Reductions of emissions in eastern Europe would reduce the highest air pollution concentrations and associated health risks. However, since air masses from the southwest are more frequent, emissions in the western part of Europe are more important for annual mean premature mortality. (orig.)

Vehicle engine sound design based on an active noise control system

Energy Technology Data Exchange (ETDEWEB)

Lewis, M. [Siemens VDO Automotive, Auburn Hills, MI (United States)

2002-07-01

A study has been carried out to identify the types of vehicle engine sounds that drivers prefer while driving at different locations and under different driving conditions. An active noise control system controlled the sound at the air intake orifice of a vehicle engine's first sixteen orders and half orders. The active noise control system was used to change the engine sound to quiet, harmonic, high harmonic, spectral shaped and growl. Videos were made of the roads traversed, binaural recording of vehicle interior sounds, and vibrations of the vehicle floor pan. Jury tapes were made up for day driving, nighttime driving and driving in the rain during the day for each of the sites. Jurors used paired comparisons to evaluate the vehicle interior sounds while sitting in a vehicle simulator developed by Siemens VDO that replicated videos of the road traversed, binaural recording of the vehicle interior sounds and vibrations of the floor pan and seat. (orig.) [German] Im Rahmen einer Studie wurden Typen von Motorgeraeuschen identifiziert, die von Fahrern unter verschiedenen Fahrbedingungen als angenehm empfunden werden. Ein System zur aktiven Geraeuschbeeinflussung am Ansauglufteinlass im Bereich des Luftfilters modifizierte den Klang des Motors bis zur 16,5ten Motorordnung, und zwar durch Bedaempfung, Verstaerkung und Filterung der Signalfrequenzen. Waehrend der Fahrt wurden Videoaufnahmen der befahrenen Strassen, Stereoaufnahmen der Fahrzeuginnengeraeusche und Aufnahmen der Vibrationsamplituden des Fahrzeugbodens erstellt; dies bei Tag- und Nachtfahrten und bei Tagfahrten im Regen. Zur Beurteilung der aufgezeichneten Geraeusche durch Versuchspersonen wurde ein Fahrzeug-Laborsimulator mit Fahrersitz, Bildschirm, Lautsprecher und mechanischer Erregung der Bodenplatte aufgebaut, um die aufgenommenen Signale moeglichst wirklichkeitsgetreu wiederzugeben. (orig.)

Fullerene Soot in Eastern China Air: Results from Soot Particle-Aerosol Mass Spectrometer

Science.gov (United States)

Wang, J.; Ge, X.; Chen, M.; Zhang, Q.; Yu, H.; Sun, Y.; Worsnop, D. R.; Collier, S.

2015-12-01

In this work, we present for the first time, the observation and quantification of fullerenes in ambient airborne particulate using an Aerodyne Soot Particle - Aerosol Mass Spectrometer (SP-AMS) deployed during 2015 winter in suburban Nanjing, a megacity in eastern China. The laser desorption and electron impact ionization techniques employed by the SP-AMS allow us to differentiate various fullerenes from other aerosol components. Mass spectrum of the identified fullerene soot is consisted by a series of high molecular weight carbon clusters (up to m/z of 2000 in this study), almost identical to the spectral features of commercially available fullerene soot, both with C70 and C60 clusters as the first and second most abundant species. This type of soot was observed throughout the entire study period, with an average mass loading of 0.18 μg/m3, accounting for 6.4% of the black carbon mass, 1.2% of the total organic mass. Temporal variation and diurnal pattern of fullerene soot are overall similar to those of black carbon, but are clearly different in some periods. Combining the positive matrix factorization, back-trajectory and analyses of the meteorological parameters, we identified the petrochemical industrial plants situating upwind from the sampling site, as the major source of fullerene soot. In this regard, our findings imply the ubiquitous presence of fullerene soot in ambient air of industry-influenced area, especially the oil and gas production regions. This study also offers new insights into the characterization of fullerenes from other environmental samples via the advanced SP-AMS technique.

Influence of Wall Surface and Air Modelling in Finite-Element Analysis of Sound Transmission Between Rooms in Lightweight Buildings

DEFF Research Database (Denmark)

Andersen, Lars Vabbersgaard; Kirkegaard, Poul Henning; Dickow, Kristoffer Ahrens

2012-01-01

Noise is a nuisance in the built environment, and to avoid undesirable transmission of sound and vibration within a building, its vibro-acoustic performance must be addressed in the design phase. For heavy structures, a reliable assessment of the sound pressure levels can be made by statistical...

Visual Representation in GENESIS as a tool for Physical Modeling, Sound Synthesis and Musical Composition

OpenAIRE

Villeneuve, Jérôme; Cadoz, Claude; Castagné, Nicolas

2015-01-01

The motivation of this paper is to highlight the importance of visual representations for artists when modeling and simulating mass-interaction physical networks in the context of sound synthesis and musical composition. GENESIS is a musician-oriented software environment for sound synthesis and musical composition. However, despite this orientation, a substantial amount of effort has been put into building a rich variety of tools based on static or dynamic visual representations of models an...

An alternative respiratory sounds classification system utilizing artificial neural networks

Directory of Open Access Journals (Sweden)

Rami J Oweis

2015-04-01

Full Text Available Background: Computerized lung sound analysis involves recording lung sound via an electronic device, followed by computer analysis and classification based on specific signal characteristics as non-linearity and nonstationarity caused by air turbulence. An automatic analysis is necessary to avoid dependence on expert skills. Methods: This work revolves around exploiting autocorrelation in the feature extraction stage. All process stages were implemented in MATLAB. The classification process was performed comparatively using both artificial neural networks (ANNs and adaptive neuro-fuzzy inference systems (ANFIS toolboxes. The methods have been applied to 10 different respiratory sounds for classification. Results: The ANN was superior to the ANFIS system and returned superior performance parameters. Its accuracy, specificity, and sensitivity were 98.6%, 100%, and 97.8%, respectively. The obtained parameters showed superiority to many recent approaches. Conclusions: The promising proposed method is an efficient fast tool for the intended purpose as manifested in the performance parameters, specifically, accuracy, specificity, and sensitivity. Furthermore, it may be added that utilizing the autocorrelation function in the feature extraction in such applications results in enhanced performance and avoids undesired computation complexities compared to other techniques.

Light and Sound

CERN Document Server

Karam, P Andrew

2010-01-01

Our world is largely defined by what we see and hear-but our uses for light and sound go far beyond simply seeing a photo or hearing a song. A concentrated beam of light, lasers are powerful tools used in industry, research, and medicine, as well as in everyday electronics like DVD and CD players. Ultrasound, sound emitted at a high frequency, helps create images of a developing baby, cleans teeth, and much more. Light and Sound teaches how light and sound work, how they are used in our day-to-day lives, and how they can be used to learn about the universe at large.

The Textile Form of Sound

DEFF Research Database (Denmark)

Bendixen, Cecilie

Sound is a part of architecture, and sound is complex. Upon this, sound is invisible. How is it then possible to design visual objects that interact with the sound? This paper addresses the problem of how to get access to the complexity of sound and how to make textile material revealing the form...... goemetry by analysing the sound pattern at a specific spot. This analysis is done theoretically with algorithmic systems and practical with waves in water. The paper describes the experiments and the findings, and explains how an analysis of sound can be catched in a textile form....

Reduction of heart sound interference from lung sound signals using empirical mode decomposition technique.

Science.gov (United States)

Mondal, Ashok; Bhattacharya, P S; Saha, Goutam

2011-01-01

During the recording time of lung sound (LS) signals from the chest wall of a subject, there is always heart sound (HS) signal interfering with it. This obscures the features of lung sound signals and creates confusion on pathological states, if any, of the lungs. A novel method based on empirical mode decomposition (EMD) technique is proposed in this paper for reducing the undesired heart sound interference from the desired lung sound signals. In this, the mixed signal is split into several components. Some of these components contain larger proportions of interfering signals like heart sound, environmental noise etc. and are filtered out. Experiments have been conducted on simulated and real-time recorded mixed signals of heart sound and lung sound. The proposed method is found to be superior in terms of time domain, frequency domain, and time-frequency domain representations and also in listening test performed by pulmonologist.

NASA Space Sounds API

Data.gov (United States)

National Aeronautics and Space Administration — NASA has released a series of space sounds via sound cloud. We have abstracted away some of the hassle in accessing these sounds, so that developers can play with...

Physiological correlates of sound localization in a parasitoid fly, Ormia ochracea

Science.gov (United States)

Oshinsky, Michael Lee

A major focus of research in the nervous system is the investigation of neural circuits. The question of how neurons connect to form functional units has driven modern neuroscience research from its inception. From the beginning, the neural circuits of the auditory system and specifically sound localization were used as a model system for investigating neural connectivity and computation. Sound localization lends itself to this task because there is no mapping of spatial information on a receptor sheet as in vision. With only one eye, an animal would still have positional information for objects. Since the receptor sheet in the ear is frequency oriented and not spatially oriented, positional information for a sound source does not exist with only one ear. The nervous system computes the location of a sound source based on differences in the physiology of the two ears. In this study, I investigated the neural circuits for sound localization in a fly, Ormia ochracea (Diptera, Tachinidae, Ormiini), which is a parasitoid of crickets. This fly possess a unique mechanically coupled hearing organ. The two ears are contained in one air sac and a cuticular bridge, that has a flexible spring-like structure at its center, connects them. This mechanical coupling preprocesses the sound before it is detected by the nervous system and provides the fly with directional information. The subject of this study is the neural coding of the location of sound stimuli by a mechanically coupled auditory system. In chapter 1, I present the natural history of an acoustic parasitoid and I review the peripheral processing of sound by the Ormian ear. In chapter 2, I describe the anatomy and physiology of the auditory afferents. I present this physiology in the context of sound localization. In chapter 3, I describe the directional dependent physiology for the thoracic local and ascending acoustic interneurons. In chapter 4, I quantify the threshold and I detail the kinematics of the phonotactic

Spherical collapse of dark energy with an arbitrary sound speed

International Nuclear Information System (INIS)

Basse, Tobias; Bjælde, Ole Eggers; Wong, Yvonne Y.Y.

2011-01-01

We consider a generic type of dark energy fluid, characterised by a constant equation of state parameter w and sound speed c s , and investigate the impact of dark energy clustering on cosmic structure formation using the spherical collapse model. Along the way, we also discuss in detail the evolution of dark energy perturbations in the linear regime. We find that the introduction of a finite sound speed into the picture necessarily induces a scale-dependence in the dark energy clustering, which in turn affects the dynamics of the spherical collapse in a scale-dependent way. As with other, more conventional fluids, we can define a Jeans scale for the dark energy clustering, and hence a Jeans mass M J for the dark matter which feels the effect of dark energy clustering via gravitational interactions. For bound objects (halos) with masses M >> M J , the effect of dark energy clustering is maximal. For those with M J , the dark energy component is effectively homogeneous, and its role in the formation of these structures is reduced to its effects on the Hubble expansion rate. To compute quantitatively the virial density and the linearly extrapolated threshold density, we use a quasi-linear approach which is expected to be valid up to around the Jeans mass. We find an interesting dependence of these quantities on the halo mass M, given some w and c s . The dependence is the strongest for masses lying in the vicinity of M ∼ M J . Observing this M-dependence will be a tell-tale sign that dark energy is dynamic, and a great leap towards pinning down its clustering properties

AIRS-only Product on Giovanni for Exploring Up-to-date AIRS Observation and Comparing with AIRS+AMSU Product

Science.gov (United States)

Ding, F.; Hearty, T. J., III; Theobald, M.; Vollmer, B.; Wei, J.

2017-12-01

The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) has been the home of processing, archiving, and distribution services for the Atmospheric Infrared Sounder (AIRS) mission since its launch in 2002 for the global observations of the atmospheric state. Giovanni, a web-based application developed by the GES DISC, provides a simple and intuitive way to visualize, analyze, and access vast amounts of Earth science remote sensing data without having to download the data. Most important variables, including temperature and humidity profiles, outgoing longwave radiation, cloud properties, and trace gases, from version 6 AIRS product are available on Giovanni. The AIRS is an instrument suite comprised of a hyperspectral infrared instrument AIRS and two multichannel microwave instruments, the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB). As the HSB ceased operation in very early stage of AIRS mission, the AIRS project operates two parallel retrieval algorithms: one using both IR and MW measurements (AIRS+AMSU) and the other using only IR measurements (AIRS-only) for the most time of the mission. The AIRS+AMSU product is better and the variables on Giovanni are from it. However, the generation of AIRS+AMSU product has been suspended since the AMSU instrument anomaly occurred in late 2016. To continue exploring up-to-date AIRS observations, the same set of variables from the AIRS-only product are added on Giovanni by the GES DSIC. This will also support the comparison of AIRS-only with AIRS+AMSU retrievals. In the presentation, we will demonstrate the visualization of AIRS-only product and the plots/statistics of comparison with AIRS+AMSU product using Giovanni.

A terrified-sound stress induced proteomic changes in adult male rat hippocampus.

Science.gov (United States)

Yang, Juan; Hu, Lili; Wu, Qiuhua; Liu, Liying; Zhao, Lingyu; Zhao, Xiaoge; Song, Tusheng; Huang, Chen

2014-04-10

In this study, we investigated the biochemical mechanisms in the adult rat hippocampus underlying the relationship between a terrified-sound induced psychological stress and spatial learning. Adult male rats were exposed to a terrified-sound stress, and the Morris water maze (MWM) has been used to evaluate changes in spatial learning and memory. The protein expression profile of the hippocampus was examined using two-dimensional gel electrophoresis (2DE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and bioinformatics analysis. The data from the MWM tests suggested that a terrified-sound stress improved spatial learning. The proteomic analysis revealed that the expression of 52 proteins was down-regulated, while that of 35 proteins were up-regulated, in the hippocampus of the stressed rats. We identified and validated six of the most significant differentially expressed proteins that demonstrated the greatest stress-induced changes. Our study provides the first evidence that a terrified-sound stress improves spatial learning in rats, and that the enhanced spatial learning coincides with changes in protein expression in rat hippocampus. Copyright © 2014 Elsevier Inc. All rights reserved.

Transformer sound level caused by core magnetostriction and winding stress displacement variation

Directory of Open Access Journals (Sweden)

Chang-Hung Hsu

2017-05-01

Full Text Available Magnetostriction caused by the exciting variation of the magnetic core and the current conducted by the winding wired to the core has a significant result impact on a power transformer. This paper presents the sound of a factory transformer before on-site delivery for no-load tests. This paper also discusses the winding characteristics from the transformer full-load tests. The simulation and the measurement for several transformers with capacities ranging from 15 to 60 MVA and high voltage 132kV to low voltage 33 kV are performed. This study compares the sound levels for transformers by no-load test (core/magnetostriction and full-load test (winding/displacement ε. The difference between the simulated and the measured sound levels is about 3dB. The results show that the sound level depends on several parameters, including winding displacement, capacity, mass of the core and windings. Comparative results of magnetic induction of cores and the electromagnetic force of windings for no-load and full-load conditions are examined.

Transfer coefficients of energy in mass for X radiation-air: the kV relation and effective energy

International Nuclear Information System (INIS)

Teixeira, G.J.; Sousa, C.H.S.; Peixoto, J.G.P.

2014-01-01

The objective was to determine, through specific software, the mass-energy transfer coefficients by X-ray beams in air between 30-150 kV. Were generated by the Spectrum Processor program, the spectra and calculated their mass coefficients. The results behaved numerically decreasing order, ranging between 0.3733 and 0.0439 cm 2 /g, inversely proportional to the voltage used and differing behavior of mono-energetic beams above 100 keV. Values align with literal definitions of the interaction of radiation with matter, being useful for dosimetry in diagnostic radiology, including for systems not using an ionization chamber. (author)

Sound Insulation between Dwellings

DEFF Research Database (Denmark)

Rasmussen, Birgit

2011-01-01

Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

Remembering that big things sound big: Sound symbolism and associative memory.

Science.gov (United States)

Preziosi, Melissa A; Coane, Jennifer H

2017-01-01

According to sound symbolism theory, individual sounds or clusters of sounds can convey meaning. To examine the role of sound symbolic effects on processing and memory for nonwords, we developed a novel set of 100 nonwords to convey largeness (nonwords containing plosive consonants and back vowels) and smallness (nonwords containing fricative consonants and front vowels). In Experiments 1A and 1B, participants rated the size of the 100 nonwords and provided definitions to them as if they were products. Nonwords composed of fricative/front vowels were rated as smaller than those composed of plosive/back vowels. In Experiment 2, participants studied sound symbolic congruent and incongruent nonword and participant-generated definition pairings. Definitions paired with nonwords that matched the size and participant-generated meanings were recalled better than those that did not match. When the participant-generated definitions were re-paired with other nonwords, this mnemonic advantage was reduced, although still reliable. In a final free association study, the possibility that plosive/back vowel and fricative/front vowel nonwords elicit sound symbolic size effects due to mediation from word neighbors was ruled out. Together, these results suggest that definitions that are sound symbolically congruent with a nonword are more memorable than incongruent definition-nonword pairings. This work has implications for the creation of brand names and how to create brand names that not only convey desired product characteristics, but also are memorable for consumers.

Investigation of tungsten mass transfer in rarefied air oxygen and water vapors

International Nuclear Information System (INIS)

Evsikov, A.S.; Makeev, A.A.; Lyubimova, L.L.; Sinyavskij, V.V.

1989-01-01

The results of experimental investigations of oxygen and water vapor effect on the rate of tungsten evaporation are presented. Methods for carrying out an experiment are presented. The experiments are carried out at the 2600 degC tungsten wire temperature and the pressure of oxygen and water vapors (2x10 -3 -5) Pa. Registration of final products of mass transfer is carried out by the DRON-2.0 diffractometer using a detachable substrate. Empirical dependence taking into account oxygen and water vapor effect on the rate of tungsten evaporation is suggested. It is marked that air oxygen and water vapor increase evaporation rate uniformly the difference is observed only in final products of interaction

An Antropologist of Sound

DEFF Research Database (Denmark)

Groth, Sanne Krogh

2015-01-01

PROFESSOR PORTRAIT: Sanne Krogh Groth met Holger Schulze, newly appointed professor in Musicology at the Department for Arts and Cultural Studies, University of Copenhagen, to a talk about anthropology of sound, sound studies, musical canons and ideology.......PROFESSOR PORTRAIT: Sanne Krogh Groth met Holger Schulze, newly appointed professor in Musicology at the Department for Arts and Cultural Studies, University of Copenhagen, to a talk about anthropology of sound, sound studies, musical canons and ideology....

Community Response to Multiple Sound Sources: Integrating Acoustic and Contextual Approaches in the Analysis

Directory of Open Access Journals (Sweden)

Peter Lercher

2017-06-01

Full Text Available Sufficient data refer to the relevant prevalence of sound exposure by mixed traffic sources in many nations. Furthermore, consideration of the potential effects of combined sound exposure is required in legal procedures such as environmental health impact assessments. Nevertheless, current practice still uses single exposure response functions. It is silently assumed that those standard exposure-response curves accommodate also for mixed exposures—although some evidence from experimental and field studies casts doubt on this practice. The ALPNAP-study population (N = 1641 shows sufficient subgroups with combinations of rail-highway, highway-main road and rail-highway-main road sound exposure. In this paper we apply a few suggested approaches of the literature to investigate exposure-response curves and its major determinants in the case of exposure to multiple traffic sources. Highly/moderate annoyance and full scale mean annoyance served as outcome. The results show several limitations of the current approaches. Even facing the inherent methodological limitations (energy equivalent summation of sound, rating of overall annoyance the consideration of main contextual factors jointly occurring with the sources (such as vibration, air pollution or coping activities and judgments of the wider area soundscape increases the variance explanation from up to 8% (bivariate, up to 15% (base adjustments up to 55% (full contextual model. The added predictors vary significantly, depending on the source combination. (e.g., significant vibration effects with main road/railway, not highway. Although no significant interactions were found, the observed additive effects are of public health importance. Especially in the case of a three source exposure situation the overall annoyance is already high at lower levels and the contribution of the acoustic indicators is small compared with the non-acoustic and contextual predictors. Noise mapping needs to go down to

Speed of sound as a function of temperature and pressure for propane derivatives

International Nuclear Information System (INIS)

Yebra, Francisco; Zemánková, Katerina; Troncoso, Jacobo

2017-01-01

Highlights: • New speed of sound data for six propane derivatives is reported. • Temperature and pressure ranges: (283.15–343.15) K and (0.1–95) MPa. • Data are compared with those available for other propane derivatives. • Temperature and pressure dependencies of sound speed are analyzed. - Abstract: The speed of sound in the temperature and pressure intervals (283.15–343.15) K and (0.1–95) MPa was measured for nitropropane, propionitrile, 1,2-dichloropropane, 1,3-dichloropropane, propylamine and propionic acid. An apparatus based on the acoustic wave time of flight determination, with a fully automatized temperature and pressure control, was used to this aim. The speed of sound derivatives against temperature and pressure, as well as the nonlinear acoustic coefficient was obtained from experimental values. The results are analyzed and compared with previously reported data for other propane derivatives: propane, 1-propanol, propanone, d-propanone, and several fluoropropanes. All obtained magnitudes are rationalized basing on the physicochemical properties of these fluids. Nearness to critical point and molar mass are revealed as key factors as regards the speed of sound behavior against temperature and pressure.

Intensive treatment with ultrasound visual feedback for speech sound errors in childhood apraxia

Directory of Open Access Journals (Sweden)

Jonathan L Preston

2016-08-01

Full Text Available Ultrasound imaging is an adjunct to traditional speech therapy that has shown to be beneficial in the remediation of speech sound errors. Ultrasound biofeedback can be utilized during therapy to provide clients additional knowledge about their tongue shapes when attempting to produce sounds that are in error. The additional feedback may assist children with childhood apraxia of speech in stabilizing motor patterns, thereby facilitating more consistent and accurate productions of sounds and syllables. However, due to its specialized nature, ultrasound visual feedback is a technology that is not widely available to clients. Short-term intensive treatment programs are one option that can be utilized to expand access to ultrasound biofeedback. Schema-based motor learning theory suggests that short-term intensive treatment programs (massed practice may assist children in acquiring more accurate motor patterns. In this case series, three participants ages 10-14 diagnosed with childhood apraxia of speech attended 16 hours of speech therapy over a two-week period to address residual speech sound errors. Two participants had distortions on rhotic sounds, while the third participant demonstrated lateralization of sibilant sounds. During therapy, cues were provided to assist participants in obtaining a tongue shape that facilitated a correct production of the erred sound. Additional practice without ultrasound was also included. Results suggested that all participants showed signs of acquisition of sounds in error. Generalization and retention results were mixed. One participant showed generalization and retention of sounds that were treated; one showed generalization but limited retention; and the third showed no evidence of generalization or retention. Individual characteristics that may facilitate generalization are discussed. Short-term intensive treatment programs using ultrasound biofeedback may result in the acquisition of more accurate motor

Ring waves as a mass transport mechanism in air-driven core-annular flows.

Science.gov (United States)

Camassa, Roberto; Forest, M Gregory; Lee, Long; Ogrosky, H Reed; Olander, Jeffrey

2012-12-01

Air-driven core-annular fluid flows occur in many situations, from lung airways to engineering applications. Here we study, experimentally and theoretically, flows where a viscous liquid film lining the inside of a tube is forced upwards against gravity by turbulent airflow up the center of the tube. We present results on the thickness and mean speed of the film and properties of the interfacial waves that develop from an instability of the air-liquid interface. We derive a long-wave asymptotic model and compare properties of its solutions with those of the experiments. Traveling wave solutions of this long-wave model exhibit evidence of different mass transport regimes: Past a certain threshold, sufficiently large-amplitude waves begin to trap cores of fluid which propagate upward at wave speeds. This theoretical result is then confirmed by a second set of experiments that show evidence of ring waves of annular fluid propagating over the underlying creeping flow. By tuning the parameters of the experiments, the strength of this phenomenon can be adjusted in a way that is predicted qualitatively by the model.

Active control of turbulent boundary layer sound transmission into a vehicle interior

International Nuclear Information System (INIS)

Caiazzo, A; Alujević, N; Pluymers, B; Desmet, W

2016-01-01

In high speed automotive, aerospace, and railway transportation, the turbulent boundary layer (TBL) is one of the most important sources of interior noise. The stochastic pressure distribution associated with the turbulence is able to excite significantly structural vibration of vehicle exterior panels. They radiate sound into the vehicle through the interior panels. Therefore, the air flow noise becomes very influential when it comes to the noise vibration and harshness assessment of a vehicle, in particular at low frequencies. Normally, passive solutions, such as sound absorbing materials, are used for reducing the TBL-induced noise transmission into a vehicle interior, which generally improve the structure sound isolation performance. These can achieve excellent isolation performance at higher frequencies, but are unable to deal with the low-frequency interior noise components. In this paper, active control of TBL noise transmission through an acoustically coupled double panel system into a rectangular cavity is examined theoretically. The Corcos model of the TBL pressure distribution is used to model the disturbance. The disturbance is rejected by an active vibration isolation unit reacting between the exterior and the interior panels. Significant reductions of the low-frequency vibrations of the interior panel and the sound pressure in the cavity are observed. (paper)

Influence of air mass origins on optical properties and PM concentrations measured at a high mountain station located in the southwestern Mediterranean

Science.gov (United States)

Castañer, R.; Nicolás, J. F.; Crespo, J.; Yubero, E.; Galindo, N.; Caballero, S.; Pastor, C.

2017-11-01

The influence of air mass origins on aerosol optical properties and particulate matter (PM) concentrations measured from January 2014 to December 2015 at a high mountain station in the southwestern Mediterranean was analyzed. Mean values of extensive aerosol optical properties (scattering, backscattering and absorption coefficients) and PM mass fractions: σsp (30.7 ± 1.1 Mm- 1), σbsp (3.9 ± 0.1 Mm- 1), σap (2.4 ± 0.1 Mm- 1), PM10 (13.1 ± 0.6 μg·m- 3) and PM1 (4.0 ± 0.1 μg·m- 3) were in the range of values reported in most studies carried out at high altitude locations. Nevertheless, a significant variation of these concentrations according to the air mass origin has been noticed. Transport from North Africa (NAF back-trajectories) and regional recirculations (REG) were the two air mass types in which the highest values of PM concentrations and optical properties were registered. Alternatively, the lowest values were recorded under Atlantic advections. Noticeable differences between NAF and REG categories were observed when intensive optical properties of aerosols were analyzed. During NAF scenarios the lowest value of SAE (0.91 ± 0.06) was obtained as well as the greatest AAE value (1.30 ± 0.02), with daily levels higher than 1.90. This result suggests that OC and hematite compounds were relevant in the absorption process during NAF events. However, during REG episodes the AAE mean value declined to 1.18 ± 0.01, since the highest mean concentration of BC was recorded under this category, and the SAE value was maximum (1.70 ± 0.05) due to the smaller size of PM. It has also been documented that during the study period a great number of REG back-trajectories occurred just after the transport of air masses from North Africa. In these situations, AAE and SAE values showed slight variations due to the persistence of mineral dust in the local atmosphere.

Size distributions of non-volatile particle residuals (Dp<800 nm at a rural site in Germany and relation to air mass origin

Directory of Open Access Journals (Sweden)

T. Tuch

2007-11-01

Full Text Available Atmospheric aerosol particle size distributions at a continental background site in Eastern Germany were examined for a one-year period. Particles were classified using a twin differential mobility particle sizer in a size range between 3 and 800 nm. As a novelty, every second measurement of this experiment involved the removal of volatile chemical compounds in a thermodenuder at 300°C. This concept allowed to quantify the number size distribution of non-volatile particle cores – primarily associated with elemental carbon, and to compare this to the original non-conditioned size distribution. As a byproduct of the volatility analysis, new particles originating from nucleation inside the thermodenuder can be observed, however, overwhelmingly at diameters below 6 nm. Within the measurement uncertainty, every particle down to particle sizes of 15 nm is concluded to contain a non-volatile core. The volume fraction of non-volatile particulate matter (non-conditioned diameter < 800 nm varied between 10 and 30% and was largely consistent with the experimentally determined mass fraction of elemental carbon. The average size of the non-volatile particle cores was estimated as a function of original non-conditioned size using a summation method, which showed that larger particles (>200 nm contained more non-volatile compounds than smaller particles (<50 nm, thus indicating a significantly different chemical composition. Two alternative air mass classification schemes based on either, synoptic chart analysis (Berliner Wetterkarte or back trajectories showed that the volume and number fraction of non-volatile cores depended less on air mass than the total particle number concentration. In all air masses, the non-volatile size distributions showed a more and a less volatile ("soot" mode, the latter being located at about 50 nm. During unstable conditions and in maritime air masses, smaller values were observed compared to stable or continental conditions

Sound specificity effects in spoken word recognition: The effect of integrality between words and sounds

DEFF Research Database (Denmark)

Strori, Dorina; Zaar, Johannes; Cooke, Martin

2017-01-01

Recent evidence has shown that nonlinguistic sounds co-occurring with spoken words may be retained in memory and affect later retrieval of the words. This sound-specificity effect shares many characteristics with the classic voice-specificity effect. In this study, we argue that the sound......-specificity effect is conditional upon the context in which the word and sound coexist. Specifically, we argue that, besides co-occurrence, integrality between words and sounds is a crucial factor in the emergence of the effect. In two recognition-memory experiments, we compared the emergence of voice and sound...... from a mere co-occurrence context effect by removing the intensity modulation. The absence of integrality led to the disappearance of the sound-specificity effect. Taken together, the results suggest that the assimilation of background sounds into memory cannot be reduced to a simple context effect...

Active sound reduction system and method

NARCIS (Netherlands)

2016-01-01

The present invention refers to an active sound reduction system and method for attenuation of sound emitted by a primary sound source, especially for attenuation of snoring sounds emitted by a human being. This system comprises a primary sound source, at least one speaker as a secondary sound

Performance Improvement of Membrane Stress Measurement Equipment through Evaluation of Added Mass of Membrane and Error Correction

Directory of Open Access Journals (Sweden)

Sang-Wook Jin

2017-01-01

Full Text Available One of the most important issues in keeping membrane structures in stable condition is to maintain the proper stress distribution over the membrane. However, it is difficult to determine the quantitative real stress level in the membrane after the completion of the structure. The stress relaxation phenomenon of the membrane and the fluttering effect due to strong wind or ponding caused by precipitation may cause severe damage to the membrane structure itself. Therefore, it is very important to know the magnitude of the existing stress in membrane structures for their maintenance. The authors have proposed a new method for separately estimating the membrane stress in two different directions using sound waves instead of directly measuring the membrane stress. The new method utilizes the resonance phenomenon of the membrane, which is induced by sound excitations given through an audio speaker. During such experiment, the effect of the surrounding air on the vibrating membrane cannot be overlooked in order to assure high measurement precision. In this paper, an evaluation scheme for the added mass of membrane with the effect of air on the vibrating membrane and the correction of measurement error is discussed. In addition, three types of membrane materials are used in the experiment in order to verify the expandability and accuracy of the membrane measurement equipment.

Forced sound transmission through a finite-sized single leaf panel subject to a point source excitation.

Science.gov (United States)

Wang, Chong

2018-03-01

In the case of a point source in front of a panel, the wavefront of the incident wave is spherical. This paper discusses spherical sound waves transmitting through a finite sized panel. The forced sound transmission performance that predominates in the frequency range below the coincidence frequency is the focus. Given the point source located along the centerline of the panel, forced sound transmission coefficient is derived through introducing the sound radiation impedance for spherical incident waves. It is found that in addition to the panel mass, forced sound transmission loss also depends on the distance from the source to the panel as determined by the radiation impedance. Unlike the case of plane incident waves, sound transmission performance of a finite sized panel does not necessarily converge to that of an infinite panel, especially when the source is away from the panel. For practical applications, the normal incidence sound transmission loss expression of plane incident waves can be used if the distance between the source and panel d and the panel surface area S satisfy d/S>0.5. When d/S ≈0.1, the diffuse field sound transmission loss expression may be a good approximation. An empirical expression for d/S=0  is also given.

Sound Symbolism in Basic Vocabulary

Directory of Open Access Journals (Sweden)

Søren Wichmann

2010-04-01

Full Text Available The relationship between meanings of words and their sound shapes is to a large extent arbitrary, but it is well known that languages exhibit sound symbolism effects violating arbitrariness. Evidence for sound symbolism is typically anecdotal, however. Here we present a systematic approach. Using a selection of basic vocabulary in nearly one half of the world’s languages we find commonalities among sound shapes for words referring to same concepts. These are interpreted as due to sound symbolism. Studying the effects of sound symbolism cross-linguistically is of key importance for the understanding of language evolution.

Interrelationships Between Walkability, Air Pollution, Greenness, and Body Mass Index.

Science.gov (United States)

James, Peter; Kioumourtzoglou, Marianthi-Anna; Hart, Jaime E; Banay, Rachel F; Kloog, Itai; Laden, Francine

2017-11-01

Recent studies have linked urban environmental factors and body mass index (BMI); however, such factors are often examined in isolation, ignoring correlations across exposures. Using data on Nurses' Health Study participants living in the Northeastern United States in 2006, we estimated associations between neighborhood walkability (a composite of population density, street connectivity, and business access), greenness (from satellite imagery), and ambient air pollution (from satellite-based spatiotemporally resolved PM2.5 predictions and weighted monthly average concentrations of NO2 from up to five nearest monitors) and self-reported BMI using generalized additive models, allowing for deviations from linearity using penalized splines. Among 23,435 women aged 60-87 years, we observed nonlinear associations between walkability and BMI and between PM2.5 and BMI in single-exposure models adjusted for age, race, and individual- and area-level socioeconomic status. When modeling all exposures simultaneously, only the association between walkability and BMI remained nonlinear and nonmonotonic. Increasing walkability was associated with increasing BMI at lower levels of walkability (walkability index walkability was linked to lower BMI in areas of higher walkability (walkability index >1.8). A 10 percentile increase in walkability, right above 1.8 was associated with a 0.84% decrease in log BMI. The relationship between walkability and BMI existed only among younger participants (walkability was nonlinearly linked to lower BMI independent of air pollution and greenness. Our findings highlight the importance of accounting for nonlinear confounding by interrelated urban environmental factors when investigating associations between the environment and BMI.

Different Structures of PVA Nanofibrous Membrane for Sound Absorption Application

Directory of Open Access Journals (Sweden)

Jana Mohrova

2012-01-01

Full Text Available The thin nanofibrous layer has different properties in the field of sound absorption in comparison with porous fibrous material which works on a principle of friction of air particles in contact with walls of pores. In case of the thin nanofibrous layer, which represents a sound absorber here, the energy of sonic waves is absorbed by the principle of membrane resonance. The structure of the membrane can play an important role in the process of converting the sonic energy to a different energy type. The vibration system acts differently depending on the presence of smooth fibers in the structure, amount of partly merged fibers, or structure of polymer foil as extreme. Polyvinyl alcohol (PVA was used as a polymer because of its good water solubility. It is possible to influence the structure of nanofibrous layer during the production process thanks to this property of polyvinyl alcohol.

Sounding the Alarm: An Introduction to Ecological Sound Art

Directory of Open Access Journals (Sweden)

Jonathan Gilmurray

2016-12-01

Full Text Available In recent years, a number of sound artists have begun engaging with ecological issues through their work, forming a growing movement of ˝ecological sound art˝. This paper traces its development, examines its influences, and provides examples of the artists whose work is currently defining this important and timely new field.

Study of noise in offices with window-type room air-conditioners

International Nuclear Information System (INIS)

Shaikh, G.H.; Hashmi, R.; Shareef, A.

2005-01-01

A Study of Noise has been carried out in 17 private offices, with window-type room air-conditioners, to assess noise levels in these offices. A-Weighted equivalent sound-pressure levels (dB(A) LAeq) and equivalent octave-band sound-pressure levels (dB Leq) were measured in each office, and Preferred Speech Interference Levels (PSIL) evaluated. The results show that the interior noise-levels in these offices vary from 59.6 to 72.2 dB(A) LAeq. which are very high and much above the interior noise limits, recommended for offices by some individual workers. Some ways and means to limit its emission of high level of noise from the air conditioners are also discussed. (author)

Sound Stuff? Naïve materialism in middle-school students' conceptions of sound

Science.gov (United States)

Eshach, Haim; Schwartz, Judah L.

2006-06-01

Few studies have dealt with students’ preconceptions of sounds. The current research employs Reiner et al. (2000) substance schema to reveal new insights about students’ difficulties in understanding this fundamental topic. It aims not only to detect whether the substance schema is present in middle school students’ thinking, but also examines how students use the schema’s properties. It asks, moreover, whether the substance schema properties are used as islands of local consistency or whether one can identify more global coherent consistencies among the properties that the students use to explain the sound phenomena. In-depth standardized open-ended interviews were conducted with ten middle school students. Consistent with the substance schema, sound was perceived by our participants as being pushable, frictional, containable, or transitional. However, sound was also viewed as a substance different from the ordinary with respect to its stability, corpuscular nature, additive properties, and inertial characteristics. In other words, students’ conceptions of sound do not seem to fit Reiner et al.’s schema in all respects. Our results also indicate that students’ conceptualization of sound lack internal consistency. Analyzing our results with respect to local and global coherence, we found students’ conception of sound is close to diSessa’s “loosely connected, fragmented collection of ideas.” The notion that sound is perceived only as a “sort of a material,” we believe, requires some revision of the substance schema as it applies to sound. The article closes with a discussion concerning the implications of the results for instruction.

Sound symbolism: the role of word sound in meaning.

Science.gov (United States)

Svantesson, Jan-Olof

2017-09-01

The question whether there is a natural connection between sound and meaning or if they are related only by convention has been debated since antiquity. In linguistics, it is usually taken for granted that 'the linguistic sign is arbitrary,' and exceptions like onomatopoeia have been regarded as marginal phenomena. However, it is becoming more and more clear that motivated relations between sound and meaning are more common and important than has been thought. There is now a large and rapidly growing literature on subjects as ideophones (or expressives), words that describe how a speaker perceives a situation with the senses, and phonaesthemes, units like English gl-, which occur in many words that share a meaning component (in this case 'light': gleam, glitter, etc.). Furthermore, psychological experiments have shown that sound symbolism in one language can be understood by speakers of other languages, suggesting that some kinds of sound symbolism are universal. WIREs Cogn Sci 2017, 8:e1441. doi: 10.1002/wcs.1441 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

Analysis of environmental sounds

Science.gov (United States)

Lee, Keansub

Environmental sound archives - casual recordings of people's daily life - are easily collected by MPS players or camcorders with low cost and high reliability, and shared in the web-sites. There are two kinds of user generated recordings we would like to be able to handle in this thesis: Continuous long-duration personal audio and Soundtracks of short consumer video clips. These environmental recordings contain a lot of useful information (semantic concepts) related with activity, location, occasion and content. As a consequence, the environment archives present many new opportunities for the automatic extraction of information that can be used in intelligent browsing systems. This thesis proposes systems for detecting these interesting concepts on a collection of these real-world recordings. The first system is to segment and label personal audio archives - continuous recordings of an individual's everyday experiences - into 'episodes' (relatively consistent acoustic situations lasting a few minutes or more) using the Bayesian Information Criterion and spectral clustering. The second system is for identifying regions of speech or music in the kinds of energetic and highly-variable noise present in this real-world sound. Motivated by psychoacoustic evidence that pitch is crucial in the perception and organization of sound, we develop a noise-robust pitch detection algorithm to locate speech or music-like regions. To avoid false alarms resulting from background noise with strong periodic components (such as air-conditioning), a new scheme is added in order to suppress these noises in the domain of autocorrelogram. In addition, the third system is to automatically detect a large set of interesting semantic concepts; which we chose for being both informative and useful to users, as well as being technically feasible. These 25 concepts are associated with people's activities, locations, occasions, objects, scenes and sounds, and are based on a large collection of

Acoustic behavior of a fibrous bulk material. [Kevlar 29 sound absorber

Science.gov (United States)

Hersh, A. S.; Walker, B.

1979-01-01

A semiempirical model is presented describing the acoustic behavior of Kevlar 29, a bulk absorbing material. The model is based on an approximate solution to the one-dimensional equations representing conservation of fluctuating mass, momentum and energy. By treating the material as a momentum sink, theoretical expressions of the material complex propagation constants and characteristic impedance were derived in terms of a single constant. Evaluating the constant at a single frequency for a particular specimen, excellent agreement between prediction and measurement was achieved for a large range of sound frequencies and material porosities and thicknesses. Results show that Kevlar 29 absorbs sound efficiently even at low frequencies. This is explained in terms of a frequency dependent material phase speed.

Sound-by-sound thalamic stimulation modulates midbrain auditory excitability and relative binaural sensitivity in frogs.

Science.gov (United States)

Ponnath, Abhilash; Farris, Hamilton E

2014-01-01

Descending circuitry can modulate auditory processing, biasing sensitivity to particular stimulus parameters and locations. Using awake in vivo single unit recordings, this study tested whether electrical stimulation of the thalamus modulates auditory excitability and relative binaural sensitivity in neurons of the amphibian midbrain. In addition, by using electrical stimuli that were either longer than the acoustic stimuli (i.e., seconds) or presented on a sound-by-sound basis (ms), experiments addressed whether the form of modulation depended on the temporal structure of the electrical stimulus. Following long duration electrical stimulation (3-10 s of 20 Hz square pulses), excitability (spikes/acoustic stimulus) to free-field noise stimuli decreased by 32%, but returned over 600 s. In contrast, sound-by-sound electrical stimulation using a single 2 ms duration electrical pulse 25 ms before each noise stimulus caused faster and varied forms of modulation: modulation lasted sound-by-sound electrical stimulation varied between different acoustic stimuli, including for different male calls, suggesting modulation is specific to certain stimulus attributes. For binaural units, modulation depended on the ear of input, as sound-by-sound electrical stimulation preceding dichotic acoustic stimulation caused asymmetric modulatory effects: sensitivity shifted for sounds at only one ear, or by different relative amounts for both ears. This caused a change in the relative difference in binaural sensitivity. Thus, sound-by-sound electrical stimulation revealed fast and ear-specific (i.e., lateralized) auditory modulation that is potentially suited to shifts in auditory attention during sound segregation in the auditory scene.

Sound specificity effects in spoken word recognition: The effect of integrality between words and sounds.

Science.gov (United States)

Strori, Dorina; Zaar, Johannes; Cooke, Martin; Mattys, Sven L

2018-01-01

Recent evidence has shown that nonlinguistic sounds co-occurring with spoken words may be retained in memory and affect later retrieval of the words. This sound-specificity effect shares many characteristics with the classic voice-specificity effect. In this study, we argue that the sound-specificity effect is conditional upon the context in which the word and sound coexist. Specifically, we argue that, besides co-occurrence, integrality between words and sounds is a crucial factor in the emergence of the effect. In two recognition-memory experiments, we compared the emergence of voice and sound specificity effects. In Experiment 1 , we examined two conditions where integrality is high. Namely, the classic voice-specificity effect (Exp. 1a) was compared with a condition in which the intensity envelope of a background sound was modulated along the intensity envelope of the accompanying spoken word (Exp. 1b). Results revealed a robust voice-specificity effect and, critically, a comparable sound-specificity effect: A change in the paired sound from exposure to test led to a decrease in word-recognition performance. In the second experiment, we sought to disentangle the contribution of integrality from a mere co-occurrence context effect by removing the intensity modulation. The absence of integrality led to the disappearance of the sound-specificity effect. Taken together, the results suggest that the assimilation of background sounds into memory cannot be reduced to a simple context effect. Rather, it is conditioned by the extent to which words and sounds are perceived as integral as opposed to distinct auditory objects.

Analysis, Synthesis, and Perception of Musical Sounds The Sound of Music

CERN Document Server

Beauchamp, James W

2007-01-01

Analysis, Synthesis, and Perception of Musical Sounds contains a detailed treatment of basic methods for analysis and synthesis of musical sounds, including the phase vocoder method, the McAulay-Quatieri frequency-tracking method, the constant-Q transform, and methods for pitch tracking with several examples shown. Various aspects of musical sound spectra such as spectral envelope, spectral centroid, spectral flux, and spectral irregularity are defined and discussed. One chapter is devoted to the control and synthesis of spectral envelopes. Two advanced methods of analysis/synthesis are given: "Sines Plus Transients Plus Noise" and "Spectrotemporal Reassignment" are covered. Methods for timbre morphing are given. The last two chapters discuss the perception of musical sounds based on discrimination and multidimensional scaling timbre models.

pH Control in Fog and Rain in East Asia: Temporal Advection of Clean Air Masses to Mt. Bamboo, Taiwan

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Otto Klemm

2015-11-01

Full Text Available Fog and rain was collected during an 18-day period in January 2011 at Mt. Bamboo, northern Taiwan. Almost 300 hourly fog samples and 16 daily rain samples were taken. One single fog sample (pH 3.17 was influenced by local volcanic activity, otherwise the pH ranged from 3.23 to 6.41 in fog and from 3.59 to 6.31 in rain. All the respective air masses arrived from the northeast, but exhibited two distinct groups: Group_1 had high concentrations of all ions (median interquartile range of total ion concentrations 3200–6200 µeq.·L−1 and low pHs (median 3.52, the respective air masses had travelled over densely populated and industrialized regions of mainland China. Group_2 was from air masses with long travel times over the ocean and relatively low total ion concentrations (80–570 µeq.·L−1 and higher pHs (median 4.80. The cleanest samples are among the cleanest reported in the literature of worldwide fog and rain. In both groups, the pH was governed by the balance of sulfate, nitrate, ammonium, and, in some cases, calcium. The variability of these ions was higher than the variability of 10−pH, which shows that the pH is a rather robust parameter in contrast to its drivers such as non-sea-salt sulfate.

Michael Jackson's Sound Stages

OpenAIRE

Morten Michelsen

2012-01-01

In order to discuss analytically spatial aspects of recorded sound William Moylan’s concept of ‘sound stage’ is developed within a musicological framework as part of a sound paradigm which includes timbre, texture and sound stage. Two Michael Jackson songs (‘The Lady in My Life’ from 1982 and ‘Scream’ from 1995) are used to: a) demonstrate the value of such a conceptualisation, and b) demonstrate that the model has its limits, as record producers in the 1990s began ignoring the conventions of...

ABOUT SOUNDS IN VIDEO GAMES

Directory of Open Access Journals (Sweden)

Denikin Anton A.

2012-12-01

Full Text Available The article considers the aesthetical and practical possibilities for sounds (sound design in video games and interactive applications. Outlines the key features of the game sound, such as simulation, representativeness, interactivity, immersion, randomization, and audio-visuality. The author defines the basic terminology in study of game audio, as well as identifies significant aesthetic differences between film sounds and sounds in video game projects. It is an attempt to determine the techniques of art analysis for the approaches in study of video games including aesthetics of their sounds. The article offers a range of research methods, considering the video game scoring as a contemporary creative practice.

Durability of air lime mortar

DEFF Research Database (Denmark)

Nielsen, Anders

2016-01-01

This contribution deals with the physical and chemical reasons why pure air lime mortars used in masonry of burned bricks exposed to outdoor climate have shown to be durable from the Middle Ages to our days. This sounds strange in modern times where pure air lime mortars are regarded as weak...... materials, which are omitted from standards for new masonry buildings, where use of hydraulic binders is prescribed. The reasons for the durability seam to be two: 1. The old mortars have high lime contents. 2. The carbonation process creates a pore structure with a fine pored outer layer and coarser pores...

”Sound [signal] noise

DEFF Research Database (Denmark)

Bjørnsten, Thomas

2012-01-01

The article discusses the intricate relationship between sound and signification through notions of noise. The emergence of new fields of sonic artistic practices has generated several questions of how to approach sound as aesthetic form and material. During the past decade an increased attention...... has been paid to, for instance, a category such as ‘sound art’ together with an equally strengthened interest in phenomena and concepts that fall outside the accepted aesthetic procedures and constructions of what we traditionally would term as musical sound – a recurring example being ‘noise’....

General Plan-Based Environmental Impact Analysis Process Environmental Assessment, Altus Air Force Base

Science.gov (United States)

2009-11-01

Level Lmax Maximum Sound Level LOP Letter of Procedure LTM Long-term monitoring MACA Mid-Air Collision Avoidance MFH Military Family Housing mgd...users. Additionally, the Air Force proactively engages in a program of public outreach to aviators, publishing Mid-Air Collision Avoidance ( MACA ...operating under VFR. The MACA contains information on preferred flight tracks, operational characteristics of high-performance military aircraft, and

Beneath sci-fi sound: primer, science fiction sound design, and American independent cinema

OpenAIRE

Johnston, Nessa

2012-01-01

Primer is a very low budget science-fiction film that deals with the subject of time travel; however, it looks and sounds quite distinctively different from other films associated with the genre. While Hollywood blockbuster sci-fi relies on “sound spectacle” as a key attraction, in contrast Primer sounds “lo-fi” and screen-centred, mixed to two channel stereo rather than the now industry-standard 5.1 surround sound. Although this is partly a consequence of the economics of its production, the...

Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

Science.gov (United States)

Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

2015-12-01

Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

Sound transmission through a double-panel construction lined with poroelastic material in the presence of mean flow

Science.gov (United States)

Zhou, Jie; Bhaskar, Atul; Zhang, Xin

2013-08-01

This paper investigates the sound transmission characteristics through a system of double-panel lined with poroelastic material in the core. The panels are surrounded by external and internal fluid media where a uniform external mean flow exists on one side. Biot's theory is used to model the porous material. Three types of constructions—bonded-bonded, bonded-unbonded and unbonded-unbonded—are considered. The effect of Mach number of the external flow on the sound transmission over a wide frequency range in a diffuse sound field is examined. External mean flow is shown to give a modest increase in transmission loss at low frequency, but a significant increase at high frequency. It is brought out that calculations based on static air on the incidence side provide a conservative estimate of sound transmission through the sandwich structure. The acoustic performance of the sandwich panel for different configurations is presented. The effect of curvature of the panel is also brought out by using shallow shell theory.

Experimental and Numerical Study of the Effects of Acoustic Sound Absorbers on the Cooling Performance of Thermally Active Building Systems

DEFF Research Database (Denmark)

Domínguez, L. Marcos; Kazanci, Ongun Berk; Rage, Nils

2017-01-01

Free-hanging horizontal and vertical sound absorbers are commonly used in buildings for room acoustic control; however, when these sound absorbers are used in combination with Thermally Active Building Systems, they will decrease the cooling performance of Thermally Active Building Systems...... and this will affect the thermal indoor environment in that space. Therefore, it is crucial to be able to quantify and model these effects in the design phase. This study quantifies experimentally the effects of horizontal and vertical free-hanging sound absorbers on the cooling performance of Thermally Active......%, respectively. With vertical sound absorbers, the decrease in cooling performance was 8%, 12%, and 14% for the corresponding cases, respectively. The numerical model predicted closely the cooling performance reduction, air temperatures and ceiling surface temperatures in most cases, while there were differences...

Sound classification of dwellings

DEFF Research Database (Denmark)

Rasmussen, Birgit

2012-01-01

National schemes for sound classification of dwellings exist in more than ten countries in Europe, typically published as national standards. The schemes define quality classes reflecting different levels of acoustical comfort. Main criteria concern airborne and impact sound insulation between...... dwellings, facade sound insulation and installation noise. The schemes have been developed, implemented and revised gradually since the early 1990s. However, due to lack of coordination between countries, there are significant discrepancies, and new standards and revisions continue to increase the diversity...... is needed, and a European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs 2009-2013, one of the main objectives being to prepare a proposal for a European sound classification scheme with a number of quality...

Vocal Imitations of Non-Vocal Sounds

Science.gov (United States)

Houix, Olivier; Voisin, Frédéric; Misdariis, Nicolas; Susini, Patrick

2016-01-01

Imitative behaviors are widespread in humans, in particular whenever two persons communicate and interact. Several tokens of spoken languages (onomatopoeias, ideophones, and phonesthemes) also display different degrees of iconicity between the sound of a word and what it refers to. Thus, it probably comes at no surprise that human speakers use a lot of imitative vocalizations and gestures when they communicate about sounds, as sounds are notably difficult to describe. What is more surprising is that vocal imitations of non-vocal everyday sounds (e.g. the sound of a car passing by) are in practice very effective: listeners identify sounds better with vocal imitations than with verbal descriptions, despite the fact that vocal imitations are inaccurate reproductions of a sound created by a particular mechanical system (e.g. a car driving by) through a different system (the voice apparatus). The present study investigated the semantic representations evoked by vocal imitations of sounds by experimentally quantifying how well listeners could match sounds to category labels. The experiment used three different types of sounds: recordings of easily identifiable sounds (sounds of human actions and manufactured products), human vocal imitations, and computational “auditory sketches” (created by algorithmic computations). The results show that performance with the best vocal imitations was similar to the best auditory sketches for most categories of sounds, and even to the referent sounds themselves in some cases. More detailed analyses showed that the acoustic distance between a vocal imitation and a referent sound is not sufficient to account for such performance. Analyses suggested that instead of trying to reproduce the referent sound as accurately as vocally possible, vocal imitations focus on a few important features, which depend on each particular sound category. These results offer perspectives for understanding how human listeners store and access long

Mass balance for lead in the California South Coast Air Basin: An update

International Nuclear Information System (INIS)

Lankey, R.L.; Davidson, C.I.; McMichael, F.C.

1998-01-01

A mass balance for lead for the year 1989 in the South Coast Air Basin has inputs to the atmosphere of 600 ± 190 kg/day and outputs of 580 ± 160 kg/day, showing rough agreement. Stationary sources are responsible for only about 5% of the total lead emissions. The bulk of the lead is emitted from vehicles using leaded gasoline (37%) and unleaded gasoline (15%), as well as from resuspension of previously deposited lead on roads (43%). Over half of the total emitted lead deposits on roads and nearby soil, while about one-third is carried out of the basin by wind. A small amount, less than 10%, is deposited on surfaces throughout the basin. These percentages are approximately the same as those in a mass balance for the same region calculated for 1972, when lead emissions from leaded gasoline were about a factor of 70 greater than leaded gas emissions in 1989. When the lead emissions re used as inputs o a simple continuously stirred flow reactor model for the basin, reasonable, agreement is obtained between calculated and measured concentrations

Sound from charged particles in liquids

International Nuclear Information System (INIS)

Askar'yan, G.A.

1980-01-01

Two directions of sound application appearing during the charged particles passing through liquid - in biology and for charged particles registration are considered. Application of this sound in radiology is determined by a contribution of its hypersound component (approximately 10 9 Hz) to radiology effect of ionizing radiation on micro-organisms and cells. Large amplitudes and pressure gradients in a hypersound wave have a pronounced destructive breaking effect on various microobjects (cells, bacteria, viruses). An essential peculiarity of these processes is the possibility of control by choosing conditions changing hypersound generation, propagation and effect. This fact may lead not only to the control by radiaiton effects but also may explain and complete the analogy of ionizing radiation and ultrasound effect on bioobjects. The second direction is acoustic registration of passing ionizing particles. It is based on the possibility of guaranteed signal reception from a shower with 10 15 -10 16 eV energy in water at distances of hundreds of meters. Usage of acoustic technique for neutrino registration in the DUMAND project permits to use a detecting volume of water with a mass of 10 9 t and higher

Sound Art Situations

DEFF Research Database (Denmark)

Krogh Groth, Sanne; Samson, Kristine

2017-01-01

and combine theories from several fields. Aspects of sound art studies, performance studies and contemporary art studies are presented in order to theoretically explore the very diverse dimensions of the two sound art pieces: Visual, auditory, performative, social, spatial and durational dimensions become......This article is an analysis of two sound art performances that took place June 2015 in outdoor public spaces in the social housing area Urbanplanen in Copenhagen, Denmark. The two performances were On the production of a poor acoustics by Brandon LaBelle and Green Interactive Biofeedback...... Environments (GIBE) by Jeremy Woodruff. In order to investigate the complex situation that arises when sound art is staged in such contexts, the authors of this article suggest exploring the events through approaching them as ‘situations’ (Doherty 2009). With this approach it becomes possible to engage...

Non-proximate mass spectrometry using a heated 1-m long PTFE tube and an air-tight APCI ion source

International Nuclear Information System (INIS)

Usmanov, Dilshadbek T.; Hiraoka, Kenzo; Wada, Hiroshi; Matsumura, Masaya; Sanada-Morimura, Sachiyo; Nonami, Hiroshi; Yamabe, Shinichi

2017-01-01

Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 °C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device. Analytes were ionized by an ac corona discharge located at 1.5 mm from the inlet of the mass spectrometer. By using the airtight ion source, all the ionized gas in the ion source was introduced into the vacuum of the mass spectrometer via only the evacuation of the mass spectrometer (1.6 l min"−"1). Sub-pg limits of detection were obtained for carbaryl and trinitrotoluene. Owing to its flexibility and high sensitivity, the sniffing tube coupled with a mass spectrometer can be used as the stethoscope for the high-sensitive gas analysis. The experimental results obtained for drugs, hydrogen peroxide and small alkanes were discussed by DFT calculations. - Highlights: • Non-proximate mass spectrometry for the trace-level gas analysis was developed. • Using a 1-m long flexible PTFE tube, it can be applicable to complicated-shape real-world samples. • By atmospheric pressure chemical ionization in the airtight ion source, sub-pg limits of detection were attained. • Adsorption of less-volatility compounds was negligible with the tube temperature at 130° C. • Novel experimental results obtained were fully examined by density functional theory calculations.

Non-proximate mass spectrometry using a heated 1-m long PTFE tube and an air-tight APCI ion source

Energy Technology Data Exchange (ETDEWEB)

Usmanov, Dilshadbek T. [Clean Energy Research Center, University of Yamanashi, Takeda-4, Kofu, Yamanashi, 400-8511 (Japan); Institute of Ion-Plasma and Laser Technologies, Durmon Yoli Street 33, 100125, Tashkent (Uzbekistan); Hiraoka, Kenzo, E-mail: hiraoka@yamanashi.ac.jp [Clean Energy Research Center, University of Yamanashi, Takeda-4, Kofu, Yamanashi, 400-8511 (Japan); Wada, Hiroshi [Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, 496 Izumi, Chikugo, Fukuoka 833-0041 (Japan); Matsumura, Masaya; Sanada-Morimura, Sachiyo [Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, Suya 2421, shiKo, Kumamoto 861-1192 (Japan); Nonami, Hiroshi [Plant Biophysics/Biochemistry Research Laboratory, Faculty of Agriculture, Ehime University, 3-5-7 T Tarumi, 790-0905, Matsuyama (Japan); Yamabe, Shinichi, E-mail: yamabesh@gmail.com [Department of Material Science, Nara Institute of Science and Technology, Takayama-cho, 8916-5, Ikoma, Nara, 630−0101 (Japan)

2017-06-22

Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 °C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device. Analytes were ionized by an ac corona discharge located at 1.5 mm from the inlet of the mass spectrometer. By using the airtight ion source, all the ionized gas in the ion source was introduced into the vacuum of the mass spectrometer via only the evacuation of the mass spectrometer (1.6 l min{sup −1}). Sub-pg limits of detection were obtained for carbaryl and trinitrotoluene. Owing to its flexibility and high sensitivity, the sniffing tube coupled with a mass spectrometer can be used as the stethoscope for the high-sensitive gas analysis. The experimental results obtained for drugs, hydrogen peroxide and small alkanes were discussed by DFT calculations. - Highlights: • Non-proximate mass spectrometry for the trace-level gas analysis was developed. • Using a 1-m long flexible PTFE tube, it can be applicable to complicated-shape real-world samples. • By atmospheric pressure chemical ionization in the airtight ion source, sub-pg limits of detection were attained. • Adsorption of less-volatility compounds was negligible with the tube temperature at 130° C. • Novel experimental results obtained were fully examined by density functional theory calculations.

75 FR 62639 - Air Ambulance and Commercial Helicopter Operations, Part 91 Helicopter Operations, and Part 135...

Science.gov (United States)

2010-10-12

... helicopter air ambulance operators implement a safety management system program that includes sound risk... partially address NTSB Safety Recommendation A-09-89 regarding the implementation of sound risk management... documents. Authority for This Rulemaking The FAA's authority to issue rules on aviation safety is found in...

Characteristic sounds facilitate visual search.

Science.gov (United States)

Iordanescu, Lucica; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

2008-06-01

In a natural environment, objects that we look for often make characteristic sounds. A hiding cat may meow, or the keys in the cluttered drawer may jingle when moved. Using a visual search paradigm, we demonstrated that characteristic sounds facilitated visual localization of objects, even when the sounds carried no location information. For example, finding a cat was faster when participants heard a meow sound. In contrast, sounds had no effect when participants searched for names rather than pictures of objects. For example, hearing "meow" did not facilitate localization of the word cat. These results suggest that characteristic sounds cross-modally enhance visual (rather than conceptual) processing of the corresponding objects. Our behavioral demonstration of object-based cross-modal enhancement complements the extensive literature on space-based cross-modal interactions. When looking for your keys next time, you might want to play jingling sounds.

Converting sunlight into audible sound by means of the photoacoustic effect: The Heliophone.

Science.gov (United States)

Roozen, N B; Glorieux, C; Liu, L; Rychtáriková, M; Van der Donck, T; Jacobs, A

2016-09-01

One hundred and thirty-five years after Alexander Graham Bell and his assistant Charles Sumner Tainter explored the photoacoustic effect, and about 40 years after Rosencwaig and Gersho modeled the effect in a photoacoustic cell configuration, the phenomenon is revisited in a "Heliophone" device that converts sunlight into sound. The light is focused on a carbon blackened copper coated Kapton foil in an acoustic cell by means of a compound parabolic collimator, and its intensity is modulated by a mechanical chopper. A horn is employed to make the sound audible without electronic amplification. The description of the photoacoustic effect that was introduced by Rosencwaig and Gersho is extended to a cell-horn configuration, in which the periodically heated air above the foil acts as an oscillating piston, driving acoustic waves in the horn. The pressure in the cavity-horn assembly is calculated by considering the air layer piston as an equivalent volume velocity source. The importance of the carbon black (soot) layer to enhance light absorption, but above all to enhance the photothermal excitation efficiency, is elucidated by means of an experimentally supported physical model.

Fluid Sounds

DEFF Research Database (Denmark)

Explorations and analysis of soundscapes have, since Canadian R. Murray Schafer's work during the early 1970's, developed into various established research - and artistic disciplines. The interest in sonic environments is today present within a broad range of contemporary art projects and in arch......Explorations and analysis of soundscapes have, since Canadian R. Murray Schafer's work during the early 1970's, developed into various established research - and artistic disciplines. The interest in sonic environments is today present within a broad range of contemporary art projects...... and in architectural design. Aesthetics, psychoacoustics, perception, and cognition are all present in this expanding field embracing such categories as soundscape composition, sound art, sonic art, sound design, sound studies and auditory culture. Of greatest significance to the overall field is the investigation...

The influence of environmental sound training on the perception of spectrally degraded speech and environmental sounds.

Science.gov (United States)

Shafiro, Valeriy; Sheft, Stanley; Gygi, Brian; Ho, Kim Thien N

2012-06-01

Perceptual training with spectrally degraded environmental sounds results in improved environmental sound identification, with benefits shown to extend to untrained speech perception as well. The present study extended those findings to examine longer-term training effects as well as effects of mere repeated exposure to sounds over time. Participants received two pretests (1 week apart) prior to a week-long environmental sound training regimen, which was followed by two posttest sessions, separated by another week without training. Spectrally degraded stimuli, processed with a four-channel vocoder, consisted of a 160-item environmental sound test, word and sentence tests, and a battery of basic auditory abilities and cognitive tests. Results indicated significant improvements in all speech and environmental sound scores between the initial pretest and the last posttest with performance increments following both exposure and training. For environmental sounds (the stimulus class that was trained), the magnitude of positive change that accompanied training was much greater than that due to exposure alone, with improvement for untrained sounds roughly comparable to the speech benefit from exposure. Additional tests of auditory and cognitive abilities showed that speech and environmental sound performance were differentially correlated with tests of spectral and temporal-fine-structure processing, whereas working memory and executive function were correlated with speech, but not environmental sound perception. These findings indicate generalizability of environmental sound training and provide a basis for implementing environmental sound training programs for cochlear implant (CI) patients.

Sound Surfing Network (SSN): Mobile Phone-based Sound Spatialization with Audience Collaboration

OpenAIRE

Park, Saebyul; Ban, Seonghoon; Hong, Dae Ryong; Yeo, Woon Seung

2013-01-01

SSN (Sound Surfing Network) is a performance system that provides a new musicalexperience by incorporating mobile phone-based spatial sound control tocollaborative music performance. SSN enables both the performer and theaudience to manipulate the spatial distribution of sound using the smartphonesof the audience as distributed speaker system. Proposing a new perspective tothe social aspect music appreciation, SSN will provide a new possibility tomobile music performances in the context of in...

Sound Exposure of Symphony Orchestra Musicians

DEFF Research Database (Denmark)

Schmidt, Jesper Hvass; Pedersen, Ellen Raben; Juhl, Peter Møller

2011-01-01

dBA and their left ear was exposed 4.6 dB more than the right ear. Percussionists were exposed to high sound peaks >115 dBC but less continuous sound exposure was observed in this group. Musicians were exposed up to LAeq8h of 92 dB and a majority of musicians were exposed to sound levels exceeding......Background: Assessment of sound exposure by noise dosimetry can be challenging especially when measuring the exposure of classical orchestra musicians where sound originate from many different instruments. A new measurement method of bilateral sound exposure of classical musicians was developed...... and used to characterize sound exposure of the left and right ear simultaneously in two different symphony orchestras.Objectives: To measure binaural sound exposure of professional classical musicians and to identify possible exposure risk factors of specific musicians.Methods: Sound exposure was measured...

A Method for Estimating Mass-Transfer Coefficients in a Biofilter from Membrane Inlet Mass Spectrometer Data

DEFF Research Database (Denmark)

Nielsen, Anders Michael; Nielsen, Lars Peter; Feilberg, Anders

2009-01-01

A membrane inlet mass spectrometer (MIMS) was used in combination with a developed computer model to study and improve management of a biofilter (BF) treating malodorous ventilation air from a meat rendering facility. The MIMS was used to determine percentage removal efficiencies (REs) of selected...... sulfur gases and to provide toluene retention profiles for the model to determine the air velocity and overall mass-transfer coefficient of toluene. The mass-transfer coefficient of toluene was used as a reference for determining the mass transfer of sulfur gases. By presenting the model to scenarios...... of a filter bed with a consortium of effective sulfur oxidizers, the most likely mechanism for incomplete removal of sulfur compounds from the exhaust air was elucidated. This was found to be insufficient mass transfer and not inadequate bacterial activity as anticipated by the manager of the BF. Thus...

Efficient techniques for wave-based sound propagation in interactive applications

Science.gov (United States)

Mehra, Ravish

Sound propagation techniques model the effect of the environment on sound waves and predict their behavior from point of emission at the source to the final point of arrival at the listener. Sound is a pressure wave produced by mechanical vibration of a surface that propagates through a medium such as air or water, and the problem of sound propagation can be formulated mathematically as a second-order partial differential equation called the wave equation. Accurate techniques based on solving the wave equation, also called the wave-based techniques, are too expensive computationally and memory-wise. Therefore, these techniques face many challenges in terms of their applicability in interactive applications including sound propagation in large environments, time-varying source and listener directivity, and high simulation cost for mid-frequencies. In this dissertation, we propose a set of efficient wave-based sound propagation techniques that solve these three challenges and enable the use of wave-based sound propagation in interactive applications. Firstly, we propose a novel equivalent source technique for interactive wave-based sound propagation in large scenes spanning hundreds of meters. It is based on the equivalent source theory used for solving radiation and scattering problems in acoustics and electromagnetics. Instead of using a volumetric or surface-based approach, this technique takes an object-centric approach to sound propagation. The proposed equivalent source technique generates realistic acoustic effects and takes orders of magnitude less runtime memory compared to prior wave-based techniques. Secondly, we present an efficient framework for handling time-varying source and listener directivity for interactive wave-based sound propagation. The source directivity is represented as a linear combination of elementary spherical harmonic sources. This spherical harmonic-based representation of source directivity can support analytical, data

Letter-Sound Reading: Teaching Preschool Children Print-to-Sound Processing

Science.gov (United States)

Wolf, Gail Marie

2016-01-01

This intervention study investigated the growth of letter sound reading and growth of consonant-vowel-consonant (CVC) word decoding abilities for a representative sample of 41 US children in preschool settings. Specifically, the study evaluated the effectiveness of a 3-step letter-sound teaching intervention in teaching preschool children to…

The Mass and Individual Terror in the Mirror of the Soviet and Russian Cinema (the Feature Films of the Sound Period and Media Literacy Education

Directory of Open Access Journals (Sweden)

Alexander Fedorov

2015-12-01

Full Text Available This article gives the way for hermeneutic analysis of the topic of the mass and individual terror in the mirror of the Soviet and Russian cinema (the feature films of the sound period. The hermeneutical analysis suggests media text comprehension through comparison with historical, cultural tradition and reality; penetration of its logic; through comparison of media images in historical and cultural context by combining historical, hermeneutical analysis of the structural, plot, ethical, ideological, iconographic / visual, media stereotypes and analysis of media text characters. An analysis of this kind of media texts, in our opinion, is particularly important for media literacy education of future historians, culture and art historians, sociologists, psychologists and educators.

THE ELABORATION OF THE OPTIMAL SYNTHESIS ALGORITHM FOR COMPLEX PROCESSING INFORMATION OF THE SPATIAL POSITION OF THE UPPER-AIR RADIOSONDE

Directory of Open Access Journals (Sweden)

2016-01-01

Full Text Available The article considers the elaboration of the problem of optimal algorithm synthesis of complex signal processing of satel- lite GLONASS/GPS systems navigation relayed from the Board of the upper-air radiosonde and the output data upper-air radar to determine the spatial coordinates of upper-air radiosonde. The upper-air sounding is performed with the help of technical means of radio sounding system of atmosphere, including the upper-air radiosonde, manufactured in free flight, and ground supporting equipment, which includes devices for signal processing of upper-air radiosonde and preparation of the operational upper-air mes- sages. The peculiarity of atmosphere radio sounding of domestic system is the measurement with method of radar slant range to upper-air radiosonde, the viewing angles of the antenna upper-air radar to determine azimuth and elevation of upper-air radiosonde. The disadvantage of the radar method of radiosonde support is the relatively low accuracy of determining the coordinates of the radiosonde and the possible disruption of automatic tracking in angular coordinates. Satellite navigation system based on the mi- crowave sensors has clear advantages in terms of efficiency, size, mobility, and use on mobile objects, however, with significant drawbacks associated primarily with the geometric factor and the error propagation of the navigation signal. The article presents a mathematical model useful incoherent GLONASS/GPS signals, relayed by the upper-air radiosonde, and interference on the input receiver ground point for complex information processing, and mathematical models of output data in upper-air radars.

Mass transfer behavior of tritium from air to water through the water surface

International Nuclear Information System (INIS)

Takata, Hiroki; Nishikawa, Masabumi; Kamimae, Kozo

2005-01-01

It is anticipated that a certain amount of tritiated water exists in the atmosphere of tritium handling facilities, and it is recognized that the hazardous potential of tritiated water is rather high. Then, it is important to grasp the behavior of tritiated water for preserving of the radiation safety. The mass transfer behavior of tritium from air to water through the water surface was discussed in this study. The evaporation rate of water and the condensation rate of water were experimentally examined from measurement of change of the weight of distilled water. The tritium transfer rate from the tritiated water in air to the distilled water was also experimentally examined by using a liquid scintillation counter. Experimental results about change of tritium level in a small beaker placed in the atmosphere with tritiated water showed that diffusion of tritium in water and gas flow in the atmosphere gives considerable effect on tritium transfer. The estimation method of the tritium transfer made in this study was applied to explain the data at The Japan Atomic Power Company second power station at Tsuruga and good agreement was obtained. (author)

Modelling Hyperboloid Sound Scattering

DEFF Research Database (Denmark)

Burry, Jane; Davis, Daniel; Peters, Brady

2011-01-01

The Responsive Acoustic Surfaces workshop project described here sought new understandings about the interaction between geometry and sound in the arena of sound scattering. This paper reports on the challenges associated with modelling, simulating, fabricating and measuring this phenomenon using...... both physical and digital models at three distinct scales. The results suggest hyperboloid geometry, while difficult to fabricate, facilitates sound scattering....

The influence of ski helmets on sound perception and sound localisation on the ski slope

Directory of Open Access Journals (Sweden)

Lana Ružić

2015-04-01

Full Text Available Objectives: The aim of the study was to investigate whether a ski helmet interferes with the sound localization and the time of sound perception in the frontal plane. Material and Methods: Twenty-three participants (age 30.7±10.2 were tested on the slope in 2 conditions, with and without wearing the ski helmet, by 6 different spatially distributed sound stimuli per each condition. Each of the subjects had to react when hearing the sound as soon as possible and to signalize the correct side of the sound arrival. Results: The results showed a significant difference in the ability to localize the specific ski sounds; 72.5±15.6% of correct answers without a helmet vs. 61.3±16.2% with a helmet (p < 0.01. However, the performance on this test did not depend on whether they were used to wearing a helmet (p = 0.89. In identifying the timing, at which the sound was firstly perceived, the results were also in favor of the subjects not wearing a helmet. The subjects reported hearing the ski sound clues at 73.4±5.56 m without a helmet vs. 60.29±6.34 m with a helmet (p < 0.001. In that case the results did depend on previously used helmets (p < 0.05, meaning that that regular usage of helmets might help to diminish the attenuation of the sound identification that occurs because of the helmets. Conclusions: Ski helmets might limit the ability of a skier to localize the direction of the sounds of danger and might interfere with the moment, in which the sound is firstly heard.

Investigation of the influence of air gap thickness and eccentricity on the noise of the rotating electrical machine

Directory of Open Access Journals (Sweden)

Donát M.

2013-12-01

Full Text Available This article deals with the numerical modelling of the dynamic response of the rotating electrical machine on the application of the magnetic forces. The special attention is paid to the modelling of the magnetic forces that act on the stator winding of the machine and the computational model of the modal properties of the stator winding. The created computational model was used to investigation of the influence of the nominal air gap thickness and the air gap eccentricity on the sound power radiated by outer surface of the stator of the machine. The obtained results show that the nominal air gap thickness has slightly greater influence on the sound power of the machine than eccentricity of the air gap.

Comparison of mass and energy balances for air blown and thermally ballasted fluidized bed gasifiers

International Nuclear Information System (INIS)

Lysenko, Steve; Sadaka, Samy; Brown, Robert C.

2012-01-01

The objective of this study was to compare the mass and energy balances for a conventional air blown fluidized bed gasifier and a ballasted fluidized bed gasifier developed at Iowa State University. The ballasted gasifier is an indirectly heated gasifier that uses a single reactor for both combustion and pyrolysis. Heat accumulated in high-temperature phase change material during the combustion phase is released during the pyrolysis phase to generate producer gas. Gas composition, tar and char contents, cold gas efficiency, carbon conversion, and hydrogen yield per unit biomass input were determined as part of these evaluation. During the pyrolysis phase of ballasted gasification, higher volumetric concentrations of hydrogen and methane were obtained than during air blown gasification. Hydrogen yield for ballasted gasification was 14 g kg −1 of biomass, which was about 20% higher than that obtained during air blown gasification. The higher heating value of the producer gas also reached higher levels during the ballasted pyrolysis phase than that of air blown gasification. Heating value for air blown gasification was 5.2 MJ m −3 whereas the heating value for the ballasted pyrolysis phase averaged 5.5 MJ m −3 , reaching a maximum of 8.0 MJ m −3 . The ballasted gasifier was expected to yield producer gas with average heating value as high as 15 MJ m −3 but excessive use of nitrogen to purge and cool the fuel feeder system greatly diluted the producer gas. Relatively simple redesign of the feeder system would greatly reduce the use of purge gas and may increase the heating values to about 17.5 MJ m −3 . Higher char production per kilogram of biomass was associated with the ballasted system, producing 140 g kg −1 of biomass compared to only 53 g kg −1 of biomass during air blown gasification. On the other hand, tar concentrations in the producer gas were 6.0 g m −3 for ballasted gasification compared to 11.7 g m −3 for air blown gasification. On

77 FR 37318 - Eighth Coast Guard District Annual Safety Zones; Sound of Independence; Santa Rosa Sound; Fort...

Science.gov (United States)

2012-06-21

...-AA00 Eighth Coast Guard District Annual Safety Zones; Sound of Independence; Santa Rosa Sound; Fort... Coast Guard will enforce a Safety Zone for the Sound of Independence event in the Santa Rosa Sound, Fort... during the Sound of Independence. During the enforcement period, entry into, transiting or anchoring in...

Material sound source localization through headphones

Science.gov (United States)

Dunai, Larisa; Peris-Fajarnes, Guillermo; Lengua, Ismael Lengua; Montaña, Ignacio Tortajada

2012-09-01

In the present paper a study of sound localization is carried out, considering two different sounds emitted from different hit materials (wood and bongo) as well as a Delta sound. The motivation of this research is to study how humans localize sounds coming from different materials, with the purpose of a future implementation of the acoustic sounds with better localization features in navigation aid systems or training audio-games suited for blind people. Wood and bongo sounds are recorded after hitting two objects made of these materials. Afterwards, they are analysed and processed. On the other hand, the Delta sound (click) is generated by using the Adobe Audition software, considering a frequency of 44.1 kHz. All sounds are analysed and convolved with previously measured non-individual Head-Related Transfer Functions both for an anechoic environment and for an environment with reverberation. The First Choice method is used in this experiment. Subjects are asked to localize the source position of the sound listened through the headphones, by using a graphic user interface. The analyses of the recorded data reveal that no significant differences are obtained either when considering the nature of the sounds (wood, bongo, Delta) or their environmental context (with or without reverberation). The localization accuracies for the anechoic sounds are: wood 90.19%, bongo 92.96% and Delta sound 89.59%, whereas for the sounds with reverberation the results are: wood 90.59%, bongo 92.63% and Delta sound 90.91%. According to these data, we can conclude that even when considering the reverberation effect, the localization accuracy does not significantly increase.

Reading drift in flow rate sensors caused by steady sound waves; Desvios de leitura em sensores de vazao provocados por ondas sonoras estacionarias

Energy Technology Data Exchange (ETDEWEB)

Maximiano, Celso; Nieble, Marcio D. [Coordenadoria para Projetos Especiais (COPESP), Sao Paulo, SP (Brazil); Migliavacca, Sylvana C.P.; Silva, Eduardo R.F. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

1995-12-31

The use of thermal sensors very common for the measurement of small flows of gases. In this kind of sensor a little tube forming a bypass is heated symmetrically, then the temperature distribution in the tube modifies with the mass flow along it. When a stationary wave appears in the principal tube it causes an oscillation of pressure around the average value. The sensor, located between two points of the principal tube, indicates not only the principal mass flow, but also that one caused by the difference of pressure induced by the sound wave. When the gas flows at low pressures the equipment indicates a value that do not correspond to the real. Tests and essays were realized by generating a sound wave in the principal tube, without mass flow, and the sensor detected flux. In order to solve this problem a wave-damper was constructed, installed and tested in the system and it worked satisfactory eliminating with efficiency the sound wave. (author). 2 refs., 3 figs.

Development of radio acoustic sounding method in Kharkov National University of Radio Electronics

International Nuclear Information System (INIS)

Proshkin, Y G; Kartashov, V M; Babkin, S I

2008-01-01

The analysis of the role of Kharkov National University of Radio Electronics in developing the atmosphere radio acoustic sounding (RAS) method within the period from 1968 to 2008 was carried out. As a part of the investigation program six experimental models of the sounding radio equipment were developed and manufactured. The atmosphere sounding methods were developed for measuring the base meteorological values. For the first time in the world practice, relevant comparative measurements of air temperature, wind velocity and direction were performed on a short base (about 150 m) using the centimetre RAS equipment and standard sensors of a high (300 m) meteorological mast. The RAS equipment was used for the purpose of meteorological support to investigations in the field of the atmosphere physics and applied problems. All instrumental, atmosphere and social factors, affecting operation the RAS systems, were generalized. It is shown that compact and mobile systems for remote monitoring of the atmospheric boundary layer with possible prompt obtaining of relevant information about base meteorological values in large volumes can be based on the RAS equipment

Waveform analysis of sound

CERN Document Server

Tohyama, Mikio

2015-01-01

What is this sound? What does that sound indicate? These are two questions frequently heard in daily conversation. Sound results from the vibrations of elastic media and in daily life provides informative signals of events happening in the surrounding environment. In interpreting auditory sensations, the human ear seems particularly good at extracting the signal signatures from sound waves. Although exploring auditory processing schemes may be beyond our capabilities, source signature analysis is a very attractive area in which signal-processing schemes can be developed using mathematical expressions. This book is inspired by such processing schemes and is oriented to signature analysis of waveforms. Most of the examples in the book are taken from data of sound and vibrations; however, the methods and theories are mostly formulated using mathematical expressions rather than by acoustical interpretation. This book might therefore be attractive and informative for scientists, engineers, researchers, and graduat...

Aerosol particle measurements at three stationary sites in the megacity of Paris during summer 2009: meteorology and air mass origin dominate aerosol particle composition and size distribution

Directory of Open Access Journals (Sweden)

F. Freutel

2013-01-01

Full Text Available During July 2009, a one-month measurement campaign was performed in the megacity of Paris. Amongst other measurement platforms, three stationary sites distributed over an area of 40 km in diameter in the greater Paris region enabled a detailed characterization of the aerosol particle and gas phase. Simulation results from the FLEXPART dispersion model were used to distinguish between different types of air masses sampled. It was found that the origin of air masses had a large influence on measured mass concentrations of the secondary species particulate sulphate, nitrate, ammonium, and oxygenated organic aerosol measured with the Aerodyne aerosol mass spectrometer in the submicron particle size range: particularly high concentrations of these species (about 4 μg m⁻³, 2 μg m⁻³, 2 μg m⁻³, and 7 μg m⁻³, respectively were measured when aged material was advected from continental Europe, while for air masses originating from the Atlantic, much lower mass concentrations of these species were observed (about 1 μg m⁻³, 0.2 μg m⁻³, 0.4 μg m⁻³, and 1–3 μg m⁻³, respectively. For the primary emission tracers hydrocarbon-like organic aerosol, black carbon, and NO_x it was found that apart from diurnal source strength variations and proximity to emission sources, local meteorology had the largest influence on measured concentrations, with higher wind speeds leading to larger dilution and therefore smaller measured concentrations. Also the shape of particle size distributions was affected by wind speed and air mass origin. Quasi-Lagrangian measurements performed under connected flow conditions between the three stationary sites were used to estimate the influence of the Paris emission plume onto its surroundings, which was found to be rather small. Rough estimates for the impact of the Paris emission plume on the suburban areas can be

Sound Settlements

DEFF Research Database (Denmark)

Mortensen, Peder Duelund; Hornyanszky, Elisabeth Dalholm; Larsen, Jacob Norvig

2013-01-01

Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice......Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice...

Different Structures of PVA Nano fibrous Membrane for Sound Absorption Application

International Nuclear Information System (INIS)

Mohrova, J.; Kalinova, K.

2012-01-01

The thin nano fibrous layer has different properties in the field of sound absorption in comparison with porous fibrous material which works on a principle of friction of air particles in contact with walls of pores. In case of the thin nano fibrous layer, which represents a sound absorber here, the energy of sonic waves is absorbed by the principle of membrane resonance. The structure of the membrane can play an important role in the process of converting the sonic energy to a different energy type. The vibration system acts differently depending on the presence of smooth fibers in the structure, amount of partly merged fibers, or structure of polymer foil as extreme. Polyvinyl alcohol (PVA) was used as a polymer because of its good water solubility. It is possible to influence the structure of nano fibrous layer during the production process thanks to this property of polyvinyl alcohol.

Sounds of silence: How to animate virtual worlds with sound

Science.gov (United States)

Astheimer, Peter

1993-01-01

Sounds are an integral and sometimes annoying part of our daily life. Virtual worlds which imitate natural environments gain a lot of authenticity from fast, high quality visualization combined with sound effects. Sounds help to increase the degree of immersion for human dwellers in imaginary worlds significantly. The virtual reality toolkit of IGD (Institute for Computer Graphics) features a broad range of standard visual and advanced real-time audio components which interpret an object-oriented definition of the scene. The virtual reality system 'Virtual Design' realized with the toolkit enables the designer of virtual worlds to create a true audiovisual environment. Several examples on video demonstrate the usage of the audio features in Virtual Design.

Thermal management of thermoacoustic sound projectors using a free-standing carbon nanotube aerogel sheet as a heat source.

Science.gov (United States)

Aliev, Ali E; Mayo, Nathanael K; Baughman, Ray H; Avirovik, Dragan; Priya, Shashank; Zarnetske, Michael R; Blottman, John B

2014-10-10

Carbon nanotube (CNT) aerogel sheets produce smooth-spectra sound over a wide frequency range (1-10(5) Hz) by means of thermoacoustic (TA) sound generation. Protective encapsulation of CNT sheets in inert gases between rigid vibrating plates provides resonant features for the TA sound projector and attractive performance at needed low frequencies. Energy conversion efficiencies in air of 2% and 10% underwater, which can be enhanced by further increasing the modulation temperature. Using a developed method for accurate temperature measurements for the thin aerogel CNT sheets, heat dissipation processes, failure mechanisms, and associated power densities are investigated for encapsulated multilayered CNT TA heaters and related to the thermal diffusivity distance when sheet layers are separated. Resulting thermal management methods for high applied power are discussed and deployed to construct efficient and tunable underwater sound projector for operation at relatively low frequencies, 10 Hz-10 kHz. The optimal design of these TA projectors for high-power SONAR arrays is discussed.

Thermal management of thermoacoustic sound projectors using a free-standing carbon nanotube aerogel sheet as a heat source

International Nuclear Information System (INIS)

Aliev, Ali E; Mayo, Nathanael K; Baughman, Ray H; Avirovik, Dragan; Priya, Shashank; Zarnetske, Michael R; Blottman, John B

2014-01-01

Carbon nanotube (CNT) aerogel sheets produce smooth-spectra sound over a wide frequency range (1–10 5 Hz) by means of thermoacoustic (TA) sound generation. Protective encapsulation of CNT sheets in inert gases between rigid vibrating plates provides resonant features for the TA sound projector and attractive performance at needed low frequencies. Energy conversion efficiencies in air of 2% and 10% underwater, which can be enhanced by further increasing the modulation temperature. Using a developed method for accurate temperature measurements for the thin aerogel CNT sheets, heat dissipation processes, failure mechanisms, and associated power densities are investigated for encapsulated multilayered CNT TA heaters and related to the thermal diffusivity distance when sheet layers are separated. Resulting thermal management methods for high applied power are discussed and deployed to construct efficient and tunable underwater sound projector for operation at relatively low frequencies, 10 Hz–10 kHz. The optimal design of these TA projectors for high-power SONAR arrays is discussed. (paper)

How Pleasant Sounds Promote and Annoying Sounds Impede Health: A Cognitive Approach

Directory of Open Access Journals (Sweden)

Tjeerd C. Andringa

2013-04-01

Full Text Available This theoretical paper addresses the cognitive functions via which quiet and in general pleasurable sounds promote and annoying sounds impede health. The article comprises a literature analysis and an interpretation of how the bidirectional influence of appraising the environment and the feelings of the perceiver can be understood in terms of core affect and motivation. This conceptual basis allows the formulation of a detailed cognitive model describing how sonic content, related to indicators of safety and danger, either allows full freedom over mind-states or forces the activation of a vigilance function with associated arousal. The model leads to a number of detailed predictions that can be used to provide existing soundscape approaches with a solid cognitive science foundation that may lead to novel approaches to soundscape design. These will take into account that louder sounds typically contribute to distal situational awareness while subtle environmental sounds provide proximal situational awareness. The role of safety indicators, mediated by proximal situational awareness and subtle sounds, should become more important in future soundscape research.

Sound synthesis and evaluation of interactive footsteps and environmental sounds rendering for virtual reality applications.

Science.gov (United States)

Nordahl, Rolf; Turchet, Luca; Serafin, Stefania

2011-09-01

We propose a system that affords real-time sound synthesis of footsteps on different materials. The system is based on microphones, which detect real footstep sounds from subjects, from which the ground reaction force (GRF) is estimated. Such GRF is used to control a sound synthesis engine based on physical models. Two experiments were conducted. In the first experiment, the ability of subjects to recognize the surface they were exposed to was assessed. In the second experiment, the sound synthesis engine was enhanced with environmental sounds. Results show that, in some conditions, adding a soundscape significantly improves the recognition of the simulated environment.

It sounds good!

CERN Multimedia

CERN Bulletin

2010-01-01

Both the atmosphere and we ourselves are hit by hundreds of particles every second and yet nobody has ever heard a sound coming from these processes. Like cosmic rays, particles interacting inside the detectors at the LHC do not make any noise…unless you've decided to use the ‘sonification’ technique, in which case you might even hear the Higgs boson sound like music. Screenshot of the first page of the "LHC sound" site. A group of particle physicists, composers, software developers and artists recently got involved in the ‘LHC sound’ project to make the particles at the LHC produce music. Yes…music! The ‘sonification’ technique converts data into sound. “In this way, if you implement the right software you can get really nice music out of the particle tracks”, says Lily Asquith, a member of the ATLAS collaboration and one of the initiators of the project. The ‘LHC...

Musical Sound, Instruments, and Equipment

Science.gov (United States)

Photinos, Panos

2017-12-01

'Musical Sound, Instruments, and Equipment' offers a basic understanding of sound, musical instruments and music equipment, geared towards a general audience and non-science majors. The book begins with an introduction of the fundamental properties of sound waves, and the perception of the characteristics of sound. The relation between intensity and loudness, and the relation between frequency and pitch are discussed. The basics of propagation of sound waves, and the interaction of sound waves with objects and structures of various sizes are introduced. Standing waves, harmonics and resonance are explained in simple terms, using graphics that provide a visual understanding. The development is focused on musical instruments and acoustics. The construction of musical scales and the frequency relations are reviewed and applied in the description of musical instruments. The frequency spectrum of selected instruments is explored using freely available sound analysis software. Sound amplification and sound recording, including analog and digital approaches, are discussed in two separate chapters. The book concludes with a chapter on acoustics, the physical factors that affect the quality of the music experience, and practical ways to improve the acoustics at home or small recording studios. A brief technical section is provided at the end of each chapter, where the interested reader can find the relevant physics and sample calculations. These quantitative sections can be skipped without affecting the comprehension of the basic material. Questions are provided to test the reader's understanding of the material. Answers are given in the appendix.

Direct in-vessel applications experiments at Harvard Air Cleaning Laboratory. Annual report, October 1, 1975--January 31, 1977

International Nuclear Information System (INIS)

Mallove, E.; Hinds, W.; First, M.W.

1977-02-01

Prototypes of direct in-vessel emergency air cleaning systems were evaluated for possible application in an LMFBR containment vessel after a hypothetical core disruptive accident. These were turbulence enhanced sedimentation, powder dispersal scavenging, acoustic agglomeration enhanced sedimentation, and combinations of turbulence with powder dispersal. The effect of turbulent agglomeration in enhancing the sedimentation of a sodum pool fire aerosol was experimentally demonstrated in a 90 m 3 test chamber, 4 meters high. Two hour dose reduction factors (DRF(2 hr)) from 7 to 56 were achieved in the 4 meter high chamber using fan-induced turbulent agglomeration on aerosols that varied in initial mass concentration from 1 to 12 gm/m 3 . In the same chamber, a prototype limestone powder dispersal scavenging system was tested and achieved DRF(2 hr)'s up to 10. The beneficial effect of combining turbulence with powder dispersal in a single system was demonstrated in a test which yielded a DRF(2 hr) of 20. This was greater than for either mechanism separately applied when initial aerosol mass concentration was 2 gm/m3. Acoustic agglomeration of sodium pool fire aerosols was tested in a smaller 0.65 m 3 , 75 cm high settling chamber, using an electronic siren which produced a sound pressure level of 145 dB in the reverberant chamber. The DRF(2 hr) in the small chamber with the siren operating was found to be from 17 to 31, 2 to 3 times greater than the DRF(2 hr) for unperturbed settling. Pulse-jet engines were found to be unsuitable for generating high sound levels for this application. Scaling each of the systems tested to a 30 m high containment vessel indicated no reason why one or more of the systems investigated could not be applied successfully as an emergency air cleaning system

OMNIDIRECTIONAL SOUND SOURCE

DEFF Research Database (Denmark)

1996-01-01

A sound source comprising a loudspeaker (6) and a hollow coupler (4) with an open inlet which communicates with and is closed by the loudspeaker (6) and an open outlet, said coupler (4) comprising rigid walls which cannot respond to the sound pressures produced by the loudspeaker (6). According...

Product sounds : Fundamentals and application

NARCIS (Netherlands)

Ozcan-Vieira, E.

2008-01-01

Products are ubiquitous, so are the sounds emitted by products. Product sounds influence our reasoning, emotional state, purchase decisions, preference, and expectations regarding the product and the product's performance. Thus, auditory experience elicited by product sounds may not be just about

Sound Transmission Properties of Mineral-filled High-Density Polyethylene (HDPE and Wood-HDPE Composites

Directory of Open Access Journals (Sweden)

Birm-June Kim

2014-11-01

Full Text Available Wood plastic composites (WPCs offer various advantages and potential as a competitive alternative to conventional noise barriers. For this purpose, the influence of composite formulation on the sound transmission loss (TL of WPCs needs to be fully understood. In TL testing, stiffness and surface density are major factors influencing the sound insulation property of filled plastics and WPCs. Experimental TL values decreased as sound frequency increased; and the TL values increased after passing a certain frequency level. The comparison of experimental TL curves among filled composites showed that the addition of fillers led to an increase in resonance frequency and TL values. However, at high filling levels, the stiffness decrease led to TL reductions. The experimental TL curves of filled composites, composed of mass law and stiffness law predictions, were well approximated with their combined TL predictions.

Békésy's contributions to our present understanding of sound conduction to the inner ear.

Science.gov (United States)

Puria, Sunil; Rosowski, John J

2012-11-01

In our daily lives we hear airborne sounds that travel primarily through the external and middle ear to the cochlear sensory epithelium. We also hear sounds that travel to the cochlea via a second sound-conduction route, bone conduction. This second pathway is excited by vibrations of the head and body that result from substrate vibrations, direct application of vibrational stimuli to the head or body, or vibrations induced by airborne sound. The sensation of bone-conducted sound is affected by the presence of the external and middle ear, but is not completely dependent upon their function. Measurements of the differential sensitivity of patients to airborne sound and direct vibration of the head are part of the routine battery of clinical tests used to separate conductive and sensorineural hearing losses. Georg von Békésy designed a careful set of experiments and pioneered many measurement techniques on human cadaver temporal bones, in physical models, and in human subjects to elucidate the basic mechanisms of air- and bone-conducted sound. Looking back one marvels at the sheer number of experiments he performed on sound conduction, mostly by himself without the aid of students or research associates. Békésy's work had a profound impact on the field of middle-ear mechanics and bone conduction fifty years ago when he received his Nobel Prize. Today many of Békésy's ideas continue to be investigated and extended, some have been supported by new evidence, some have been refuted, while others remain to be tested. Copyright © 2012 Elsevier B.V. All rights reserved.

Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

Science.gov (United States)

Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

2016-01-01

A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates over the evanescent sound field because of broadening of the wavenumber spectrum. Therefore, we calculated the optimum distribution of the particle velocity on the vibrating plate to reduce the broadening of the wavenumber spectrum. We focused on a window function that is utilized in the field of signal analysis for reducing the broadening of the frequency spectrum. The optimization calculation is necessary for the design of window function suitable for suppressing sound radiation and securing a spatial area for data communication. In addition, a wide frequency bandwidth is required to increase the data transmission speed. Therefore, we investigated a suitable method for calculating the sound pressure level at the far field to confirm the variation of the distribution of sound pressure level determined on the basis of the window shape and frequency. The distribution of the sound pressure level at a finite distance was in good agreement with that obtained at an infinite far field under the condition generating the evanescent sound field. Consequently, the window function was optimized by the method used to calculate the distribution of the sound pressure level at an infinite far field using the wavenumber spectrum on the vibrating plate. According to the result of comparing the distributions of the sound pressure level in the cases with and without the window function, it was confirmed that the area whose sound pressure level was reduced from the maximum level to -50 dB was

Distribution of air pollutants in the Inn Valley atmosphere during high concentration events in winter 2006

International Nuclear Information System (INIS)

Schnitzhofer, R.; Norman, M; Dunkl, J.; Wistaler, A.; Hansel, A.; Neininger, B.; Gohm, A.

2006-01-01

Full text: The goal of the INNOX field campaign, which took place during January and February 2006 near the town of Schwaz, was to obtain a three-dimensional picture of the spatial distribution of air pollutants in the Inn Valley during wintertime. For this purpose continuous ground based measurements and, on six chosen days, vertical profiles within the lowest 200 m above ground level (AGL) of the valley atmosphere of certain VOCs (benzene, toluene, etc.) and CO were performed using a proton-transfer-reaction mass spectrometry instrument (PTR-MS). For the soundings a 200-m long teflon line was fixed on a tethered balloon through which the air was sucked to the PTR-MS instrument and to a CO analyser. Next to the inlet on the tethered balloon meteorological data, such as air temperature, pressure, wind, were measured as well. Above the lowest 200 m AGL a research aircraft from MetAir AG (Switzerland), equipped with various instruments for in-situ measurements of air pollutants and meteorological data, was operated. A typical flight pattern consisted of five vertical cross sections between about 150 to 2500 m AGL and lasted about three hours. Altogether 25 hours of aircraft measurements were carried out on six different days. The combination of low-level balloon measurements and upper-level aircraft observations yields vertical profiles of various parameters which cover the whole valley atmosphere. Preliminary results which show strong vertical but also horizontal gradients of air pollutant concentrations will be presented. (author)

33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Albemarle Sound, Pamlico Sound... AND RESTRICTED AREA REGULATIONS § 334.410 Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations. (a) Target areas—(1) North Landing River (Currituck Sound...

Can we obtain the coefficient of restitution from the sound of a bouncing ball?

Science.gov (United States)

Heckel, Michael; Glielmo, Aldo; Gunkelmann, Nina; Pöschel, Thorsten

2016-03-01

The coefficient of restitution may be determined from the sound signal emitted by a sphere bouncing repeatedly off the ground. Although there is a large number of publications exploiting this method, so far, there is no quantitative discussion of the error related to this type of measurement. Analyzing the main error sources, we find that even tiny deviations of the shape from the perfect sphere may lead to substantial errors that dominate the overall error of the measurement. Therefore, we come to the conclusion that the well-established method to measure the coefficient of restitution through the emitted sound is applicable only for the case of nearly perfect spheres. For larger falling height, air drag may lead to considerable error, too.

Capital Improvement Program Environmental Assessment, Dyess Air Force Base, Texas

Science.gov (United States)

2010-09-01

Counsel • Air Force Office of Special Investigations • Air Force Audit Agency • Boeing Aerospace Operations Inc . • Defense Security Service...this corresponds to a factor of 10 in relative sound energy (Bolt, Beranek, and Meuman, Inc . 1973). Table 4-1 shows the dBA scale of commons...configuration for the B-47. Intact -Interior shop upgraded for Nike Hercules in 1961. 5020 Field Maintenance Hangar Large Aircraft Maintenance Dock

Effects of Exposure to the Sound from Seismic Airguns on Pallid Sturgeon and Paddlefish.

Directory of Open Access Journals (Sweden)

Arthur N Popper

Full Text Available This study examined the effects of exposure to a single acoustic pulse from a seismic airgun array on caged endangered pallid sturgeon (Scaphirhynchus albus and on paddlefish (Polyodon spathula in Lake Sakakawea (North Dakota, USA. The experiment was designed to detect the onset of physiological responses including minor to mortal injuries. Experimental fish were held in cages as close as 1 to 3 m from the guns where peak negative sound pressure levels (Peak- SPL reached 231 dB re 1 μPa (205 dB re 1 μPa2·s sound exposure level [SEL]. Additional cages were placed at greater distances in an attempt to develop a dose-response relationship. Treatment and control fish were then monitored for seven days, euthanized, and necropsied to determine injuries. Necropsy results indicated that the probability of delayed mortality associated with pulse pressure following the seven day monitoring period was the same for exposed and control fish of both species. Exposure to a single pulse from a small air gun array (10,160 cm3 was not lethal for pallid sturgeon and paddlefish. However, the risks from exposure to multiple sounds and to sound exposure levels that exceed those reported here remain to be examined.

Spherical collapse in quintessence models with zero speed of sound

CERN Document Server

Creminelli, Paolo; Noreña, Jorge; Senatore, Leonardo; Vernizzi, Filippo

2010-01-01

We study the spherical collapse model in the presence of quintessence with zero speed of sound. This case is particularly motivated for w<-1 as it is required by stability. As pressure gradients are negligible, quintessence follows dark matter during the collapse. The spherical overdensity behaves as a separate closed FLRW universe, so that its evolution can be studied exactly. We derive the critical overdensity for collapse and we use the extended Press-Schechter theory to study how the clustering of quintessence affects the dark matter mass function. The effect is dominated by the modification of the linear dark matter growth function. A larger effect occurs on the total mass function, which includes the quintessence overdensities. Indeed, here quintessence constitutes a third component of virialized objects, together with baryons and dark matter, and contributes to the total halo mass by a fraction ~ (1+w) Omega_Q / Omega_m. This gives a distinctive modification of the total mass function at low redshif...

Sounding out the logo shot

OpenAIRE

Nicolai Jørgensgaard Graakjær

2013-01-01

This article focuses on how sound in combination with visuals (i.e. ‘branding by’) may possibly affect the signifying potentials (i.e. ‘branding effect’) of products and corporate brands (i.e. ‘branding of’) during logo shots in television commercials (i.e. ‘branding through’). This particular focus adds both to the understanding of sound in television commercials and to the understanding of sound brands. The article firstly presents a typology of sounds. Secondly, this typology is applied...

Sound intensity

DEFF Research Database (Denmark)

Crocker, Malcolm J.; Jacobsen, Finn

1998-01-01

This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique.......This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique....

Sound Intensity

DEFF Research Database (Denmark)

Crocker, M.J.; Jacobsen, Finn

1997-01-01

This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique.......This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique....

SoleSound

DEFF Research Database (Denmark)

Zanotto, Damiano; Turchet, Luca; Boggs, Emily Marie

2014-01-01

This paper introduces the design of SoleSound, a wearable system designed to deliver ecological, audio-tactile, underfoot feedback. The device, which primarily targets clinical applications, uses an audio-tactile footstep synthesis engine informed by the readings of pressure and inertial sensors...... embedded in the footwear to integrate enhanced feedback modalities into the authors' previously developed instrumented footwear. The synthesis models currently implemented in the SoleSound simulate different ground surface interactions. Unlike similar devices, the system presented here is fully portable...